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Mladenović Nikolić N, Kljajević L, Nenadović SS, Potočnik J, Knežević S, Dolenec S, Trivunac K. Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials. Gels 2024; 10:317. [PMID: 38786234 PMCID: PMC11121154 DOI: 10.3390/gels10050317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution of solid precursors, FA, WA, and MK, by a liquid activator (Na2SiO3 and NaOH). In concentrated solutions of the activator, the formation of an aluminosilicate gel structure occurred. DRIFT spectroscopy of the AAMs indicated main vibration bands between 1036 cm-1 and 996 cm-1, corresponding to Si-O-Si/Si-O-Al bands. Shifting vibration bands were seen at 1028 cm-1 to 1021 cm-1, indicating that the Si-O-Si/Si-O-Al bond is elongating, and the bond angle is decreasing. Based on the X-ray diffraction results, alkali-activated samples consist of an amorphous phase and residual mineral phases. The characteristic "hump" of an amorphous phase in the range from 20 to 40° 2θ was observed in FA and in all AWAFA samples. By the XRD patterns of the AAMs obtained by the activation of a solid three-component system, a new crystalline phase, gehlenite, was identified. The efficiency of AAMs in removing cadmium ions from aqueous solutions was tested under various conditions. The highest values of adsorption capacity, 64.76 mg/g (AWAFA6), 67.02 mg/g (AWAFAMK6), and 72.84 mg/g mg/g (AWAMK6), were obtained for materials activated with a 6 M NaOH solution in the alkali activator. The Langmuir adsorption isotherm and pseudo-second kinetic order provided the best fit for all investigated AAMs.
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Affiliation(s)
- Nataša Mladenović Nikolić
- Department for Materials, “Vinča“ Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade, 11 000 Belgrade, Serbia; (L.K.); (S.S.N.); (S.K.)
| | - Ljiljana Kljajević
- Department for Materials, “Vinča“ Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade, 11 000 Belgrade, Serbia; (L.K.); (S.S.N.); (S.K.)
| | - Snežana S. Nenadović
- Department for Materials, “Vinča“ Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade, 11 000 Belgrade, Serbia; (L.K.); (S.S.N.); (S.K.)
| | - Jelena Potočnik
- Department of Atomic Physics, “Vinča“ Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade, 11 000 Belgrade, Serbia;
| | - Sanja Knežević
- Department for Materials, “Vinča“ Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade, 11 000 Belgrade, Serbia; (L.K.); (S.S.N.); (S.K.)
| | - Sabina Dolenec
- Slovenian National Building and Civil Engineering Institute, Dimičeva ulica 12, 1000 Ljubljana, Slovenia;
- Department of Geology, Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva ulica 12, 1000 Ljubljana, Slovenia
| | - Katarina Trivunac
- Department of Analytical Chemistry and Quality Control, Faculty of Technology and Metallurgy, University of Belgrade, 11 000 Belgrade, Serbia;
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Kashosi C, Gheni A, Gomaa E, ElGawady M. Effects of Rest Time and Curing Regime on Short- and Long-Term Strength of Class C Fly Ash-Based Alkali-Activated Mortars. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1632. [PMID: 38612146 PMCID: PMC11012440 DOI: 10.3390/ma17071632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024]
Abstract
This study investigated how different rest times affect the strength development of fly-ash-based alkali-activated mortar (AAM) over a period of 90 days. Two types of fly ash with varying calcium oxide contents of 37 and 21% were used. The rest times ranged from 2 to 36 h, and three curing methods (ambient, oven, and steam) were tested. The results showed that the rest time significantly influenced the compressive strength of the AAM. The optimal rest time was found to be between 12 and 30 h depending on the curing method and fly ash type. Beyond this range, there were only minor changes in strength. One type of fly ash (FA21) showed higher strength with longer rest times up to 30 h, while the other type (FA37) had the highest strength within a rest time range of from 12 to 24 h. Over the 90-day period, the specimens cured under ambient, oven, and steam conditions at 55 °C (131 °F) experienced increasing strength, but those steam-cured at 80 °C (176 °F) showed a decrease in strength. Analysis revealed the formation of hydration products in FA37, while FA21 showed a reduction in peaks for its main compounds. Additionally, XRD analysis revealed the formation of hydration products (CSH and CASH) in FA37, while FA21 displayed a reduction in peaks for its main compounds. EDS analysis indicated the presence of partially unreacted FA particles, highlighting the impact of curing methods on dissolving FA particles and the formation of geopolymer products (NASH and CNASH) responsible for compressive strength development.
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Affiliation(s)
- Cedric Kashosi
- Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA; (C.K.); (E.G.)
| | - Ahmed Gheni
- Civil Engineering Department, Komar University of Science and Technology, Sulaymaniyah 46001, Iraq;
| | - Eslam Gomaa
- Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA; (C.K.); (E.G.)
- Department of Structural Engineering, Faculty of Engineering, Cairo University, Giza 12613, Egypt
- Walker Consultants, New York City, NY 10018, USA
| | - Mohamed ElGawady
- Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA; (C.K.); (E.G.)
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Zhu Y, Chen D, Yu X, Liu R, Liao Y. Properties of Cementitious Materials Utilizing Seashells as Aggregate or Cement: Prospects and Challenges. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1222. [PMID: 38473694 DOI: 10.3390/ma17051222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/26/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024]
Abstract
Nowadays, the sustainable development of the construction industry has become a focus of attention. Crushing and grinding waste seashells originating from the fishery industry, such as oyster shells, cockle shells, mussel shells, and scallop shells, into different particle sizes for usage as aggregate and cement in concrete or mortar provides an effective and sustainable solution to environmental problems by reducing natural resource dependence. Numerous studies have attempted to analyze the suitability of waste seashell as a possible alternative to natural aggregates and cement in concrete or mortar. This paper presents an up-to-date review of the characteristics of different types of waste seashell, as well as the physical, mechanical, durability, and other notable functional properties of seashell concrete or mortar. From the outcome of the research, waste seashell could be an inert material, and it is important to conduct a series of proper treatment for a better-quality material. It is also seen from the results that although the mechanical properties of seashell concrete have been reduced, they all meet the required criteria set by various international standards and codes. Therefore, it is recommended that the replacement of seashells as aggregate and cement should not exceed 20% and 5%, respectively. Seashell concrete or mortar would then have sufficient workability and strength for non-structural purposes. However, there is still a lack of investigation concerning the different properties of reinforced concrete members using seashells as the replacement of aggregate or cement. Further innovative research can solidify its utilization towards sustainable development.
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Affiliation(s)
- Yunpeng Zhu
- College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China
| | - Da Chen
- College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China
- Key Laboratory of Coastal Disaster and Defense of Ministry of Education, Hohai University, Nanjing 210098, China
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, China
| | - Xiaotong Yu
- College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China
- Key Laboratory of Coastal Disaster and Defense of Ministry of Education, Hohai University, Nanjing 210098, China
| | - Ruiwen Liu
- College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China
| | - Yingdi Liao
- College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China
- Key Laboratory of Coastal Disaster and Defense of Ministry of Education, Hohai University, Nanjing 210098, China
- Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, China
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Guo L, Xu X, Wang Q, Dong X, Liu X, Lei H. Synergistic utilization of industrial waste red mud and rice husk ash for eco-friendly geopolymer preparation: enhancing strength and mitigating hazardous leaching. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:2745-2758. [PMID: 38066274 DOI: 10.1007/s11356-023-31336-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/29/2023] [Indexed: 01/18/2024]
Abstract
The prolonged stacking of substantial volumes of industrial waste red mud (RM) can have significantly hazardous effects on the environment. In order to address this critical problem, this study proposes the synergistic preparation of geopolymers utilizing RM in conjunction with another industrial waste, rice husk ash (RHA). Geopolymers with varying incorporation of RHA were prepared using sodium hydroxide and sodium silicate composite alkaline activator. The mechanical properties, microstructure, and environmental characteristics of geopolymers were investigated. The incorporation of RHA significantly enhanced the strength of RM-based geopolymers, with the highest strength of 25.40 MPa achieved at 40% incorporation. According to XRD patterns and FTIR spectra, C-(A)-S-H and N-(A)-S-H were generated during the geopolymerization, thereby enhancing the strength of geopolymers. From SEM micrographs of geopolymers, it was evident that the geopolymer matrix was constituted by the encapsulation of unreacted inert particles of RM and residual fragments of RHA with C-(A)-S-H and N-(A)-S-H. The leaching levels of trace elements and heavy metals in geopolymers are both below the regulatory thresholds, thereby effectively mitigating the presence of hazardous substances in raw materials. These findings proved that the reuse of RM and RHA for the synergistic preparation of environmentally friendly geopolymers is a promising approach to address the issue of substantial RM stacking.
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Affiliation(s)
- Lisheng Guo
- College of Construction Engineering, Jilin University, Changchun, 130026, China
| | - Xin Xu
- College of Construction Engineering, Jilin University, Changchun, 130026, China.
| | - Qing Wang
- College of Construction Engineering, Jilin University, Changchun, 130026, China
| | - Xiaoqiang Dong
- College of Civil Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xiaofeng Liu
- College of Civil Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Haomin Lei
- College of Construction Engineering, Jilin University, Changchun, 130026, China
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Xu S, Xu Z, Ji Y. Preparation and Mechanical Properties of Low Carbon Cementitious Materials with Superfine Cement Reverse Filling High-Volume Mineral Admixtures. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4814. [PMID: 37445128 DOI: 10.3390/ma16134814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023]
Abstract
In order to increase the content of mineral admixtures in cement, this study proposes a method for preparing a high-volume mineral admixture cementitious material (HMAC) using superfine cement as a reverse filling material. Firstly, superfine cement is prepared through mechanical grinding. Then, the activity of mineral admixtures (such as slag and fly ash) is enhanced by mechanical grinding, sulfate activation, and alkali activation methods. Meanwhile, the evolution of HMCM from microstructure to macroscopic mechanical behavior is studied by combining a laser particle size analyzer and a scanning electron microscope. Furthermore, the reverse filling mechanism of superfine cement on mineral admixtures under different activation conditions is proposed. Results show that superfine cement can largely improve the utilization rate of cement clinker and the compressive strength of cementitious materials. In the condition that the compressive strength is not lower than that of the control group (without mineral admixture), the content of mineral admixture can be increased to 50%, 70%, and 90% after mechanical grinding, sulfate activation, and alkali activation, respectively. Analysis indicates that the reverse filling effect of superfine cement is the main reason for improving the density of the HMCM.
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Affiliation(s)
- Shengnan Xu
- Jiangsu College of Engineering and Technology, Nantong 226006, China
- Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering, School of Mechanics & Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China
| | - Zhishan Xu
- Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering, School of Mechanics & Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China
| | - Yongsheng Ji
- Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering, School of Mechanics & Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China
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Prabhakar AK, Mohan BC, Tai MH, Yao Z, Su W, Lay-Ming Teo S, Wang CH. Green, non-toxic and efficient adsorbent from hazardous ash waste for the recovery of valuable metals and heavy metal removal from waste streams. CHEMOSPHERE 2023; 329:138524. [PMID: 37019407 DOI: 10.1016/j.chemosphere.2023.138524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 05/03/2023]
Abstract
As compared to alkali-activated geopolymers with phosphoric acid which may be used in high concentrations resulting in disposal concerns, acid-based geopolymers may have superior properties. A novel green method of converting waste ash to a geopolymer for use in adsorption applications such as water treatment is presented here. We use methanesulfonic acid, a green chemical with high acid strength and biodegradability to form geopolymers from coal and wood fly ashes. The geopolymer is characterized for its physico-chemical properties and tested for heavy metal adsorption. The material specifically adsorbs iron and lead. The geopolymer is coupled to activated carbon forming a composite, which adsorbs silver (precious metal) and manganese (hazardous metal) significantly. The adsorption pattern complies with pseudo-second order kinetics and Langmuir isotherm. Toxicity studies show while activated carbon is highly toxic, the geopolymer and the carbon-geopolymer composite have relatively less toxicity concerns.
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Affiliation(s)
- Arun Kumar Prabhakar
- Energy and Environmental Sustainability Solutions for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore; NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore
| | - Babu Cadiam Mohan
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
| | - Ming Hang Tai
- Energy and Environmental Sustainability Solutions for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore; NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore
| | - Zhiyi Yao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
| | - Weiling Su
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
| | - Serena Lay-Ming Teo
- St John's Island National Marine Laboratory, Tropical Marine Science Institute, National University of Singapore, 18 Kent Ridge Road, Singapore 119227
| | - Chi-Hwa Wang
- Energy and Environmental Sustainability Solutions for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore.
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Sun Q, Zhao S, Zhao X, Song Y, Ban X, Zhang N. Influence of different grinding degrees of fly ash on properties and reaction degrees of geopolymers. PLoS One 2023; 18:e0282927. [PMID: 36928673 PMCID: PMC10019730 DOI: 10.1371/journal.pone.0282927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/27/2023] [Indexed: 03/17/2023] Open
Abstract
This study reports the preparation of geopolymers with a mechanical performance similar to that of cement at room temperature by ground fly ash mixed with a small amount of cement. The grinding time of fly ash raw materials was 0,20,40 and 60 min, respectively. The influence of the grinding degree of the fly ash on the properties and the reaction degree of the geopolymer were investigated by XRD, SEM, EDS, and mercury compression tests. The reaction degree of the fly ash geopolymer was quantified by the selective dissolution method. Increasing the grinding degree of fly ash significantly increased the compressive strength of the geopolymer and the density of the microstructure of materials also increased. Furthermore, porosity and the average pore size decreased and the proportion of small holes in the pores gradually increased. The calculation results were in coincidence with the compressive strength test and the micro-performance test of the material, thus indicating that the selective dissolution method can reflect the influence of the grinding degree on the reaction degree of the geopolymer. Furthermore, the reaction degree of the geopolymer increased as the grinding degree of the fly ash increased. However, the growth rate of the reaction degree for the geopolymer slowed down when the fly ash was ground for more than 40 min.
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Affiliation(s)
- Qingwei Sun
- College of Civil Engineering, Liaoning Technical University, Fuxin, China
| | - Siyuan Zhao
- College of Civil Engineering, Liaoning Technical University, Fuxin, China
- * E-mail:
| | - Xuzhe Zhao
- College of Civil Engineering, Liaoning Technical University, Fuxin, China
| | - Yu Song
- College of Civil Engineering, Guangxi Key Laboratory of Mechanics and Geotechnical Engineering, Guilin University of Technology, Guilin, China
| | - Xinyu Ban
- College of Civil Engineering, Liaoning Technical University, Fuxin, China
| | - Ni Zhang
- College of Civil Engineering, Liaoning Technical University, Fuxin, China
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Xing X, Wei J, Xu W, Wang B, Luo S, Yu Q. Effect of Organic Polymers on Mechanical Property and Toughening Mechanism of Slag Geopolymer Matrix. Polymers (Basel) 2022; 14:polym14194214. [PMID: 36236162 PMCID: PMC9573140 DOI: 10.3390/polym14194214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022] Open
Abstract
In this work, two series of chemically reactive polymers, silane coupling agents (SCAs) and water-soluble polymers, were specifically designed as an additive to improve the ductility of slag geopolymer paste by vibration pressure technique. The influences of organic polymers on the fluidity, rheological behavior, mechanical property, porosity, and toughening mechanism of slag geopolymer were investigated. The polycondensation and bonding characteristics of organic-inorganic products were calculated by 1H liquid nuclear magnetic resonance (NMR) technology and Fourier transform infrared (FT-IR). The polymerization degree of composite geopolymer was evaluated by 29Si NMR and X-ray photoelectron spectroscopy (XPS). The microscopic morphology of the geopolymer matrix was analyzed using scanning electron microscopy (SEM). The results showed that the dosage of the KH570 and PAA-Na with 5 wt% behaved best in improving the flexural strength and the compressive strength of geopolymer in their corresponding organic series, respectively. The addition of polymers decreased the fluidity and the fluidity loss ratio of geopolymer slurry but reduced the harmful pores of hardened geopolymer. The organic polymers acting as bridge-fixed water molecules weakened the repulsion force, and formed a three-dimensional network through molecular interweaving in a geopolymer matrix. Methacryloxy in silane coupling agents and carboxyl group in water-soluble polymers may contribute to the improvement of hydration product structure through strong bonding with C-A-S-H. Microscopic measurements indicated that the addition of KH570 and PAA-Na in geopolymer could form 73.55% and 72.48% Si-O-Si with C-A-S-H gel, higher than the reference, and increase the polycondensation degree of C-A-S-H phase, reflected by the increased generation of Q2 and Q2(1Al) and the longer chain length, leading to a higher densified geopolymer matrix with high ductility.
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Pandey A, Kumar B. Utilization of agricultural and industrial waste as replacement of cement in pavement quality concrete: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:24504-24546. [PMID: 35064477 DOI: 10.1007/s11356-021-18189-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Over the years, supplementary cementitious materials (SCM) have been successfully utilized in concrete buildings, but they have been rarely exploited in concrete pavements. In recent years, due to the growing importance of concrete pavements, researchers have begun studying the performance of various types of SCMs from pavement perspective. The overview herein assesses the existing research associated with utilizing different kinds of silica-rich waste as SCM. For this purpose, five agricultural waste (AW) comprising rice husk ash (RHA), rice straw ash (RSA), corn cob ash (CCA), palm oil fuel ash (POFA), sugarcane bagasse ash (SBA) and three industrial by-products (IB), i.e., fly ash (FA), ground granulated blast furnace slag (GGBFS) and microsilica (MS), were selected. Their effects on various properties of concrete were exhaustively reviewed. This study also furnishes reasons for limited literature on SCMs utilization in concrete pavements. Moreover, this review accentuates the previous studies' gaps, which require further research, such as the need for dedicated standard codes for AW utilization in concrete pavements. The guidance for future research to further enhance the properties of pavement quality concrete is also given.
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Affiliation(s)
- Arunabh Pandey
- Department of Civil Engineering, IIT (BHU), Varanasi, India, 221005.
- School of Civil Engineering, MIT-World Peace University, Pune, Maharashtra, India.
| | - Brind Kumar
- Department of Civil Engineering, IIT (BHU), Varanasi, India, 221005
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Morales LF, Herrera K, López JE, Saldarriaga JF. Use of biochar from rice husk pyrolysis: assessment of reactivity in lime pastes. Heliyon 2021; 7:e08423. [PMID: 34869930 PMCID: PMC8626701 DOI: 10.1016/j.heliyon.2021.e08423] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/04/2021] [Accepted: 11/15/2021] [Indexed: 11/23/2022] Open
Abstract
Biochar has unique properties such as its porous structure, specific surface area, and stable chemical properties. The rice husk is characterized by its high content of silica, and that during the pyrolysis process it generates a considerable amount of biochar that can be used in different processes. The aim of this work is to evaluate several biochars from the pyrolysis process in the reactivity of lime pastes. For this, biochar has been obtained at four different temperatures (450, 500, 550 and 600 °C), and they have been characterized by XRF, XRD, ICP-EOS, and particle size distribution, to determine their phases and their chemical composition. Biochar has been replaced in lime pastes in different proportions (5, 10, 15, 20, 25 and 30%), and exposed to different curing times (1, 3, 7, 14, 28, 56, 90 and 180 days). It has been found that all the replacements show reactivity within the lime pastes and that the percentage of 25% in all the biochar tested could be an adequate replacement.
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Affiliation(s)
- Luisa F. Morales
- Dept. of Civil and Environmental Engineering, Universidad de Los Andes, 1Este #19A-40, 111711, Bogotá, Colombia
| | - Katherine Herrera
- Dept. of Civil and Environmental Engineering, Universidad de Los Andes, 1Este #19A-40, 111711, Bogotá, Colombia
| | - Julián E. López
- Environmental Engineering Program, Universidad de Medellín, Carrera 87 #30-65, 050026, Medellín, Colombia
| | - Juan F. Saldarriaga
- Dept. of Civil and Environmental Engineering, Universidad de Los Andes, 1Este #19A-40, 111711, Bogotá, Colombia
- Corresponding author.
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Compressive Strength of Sustainable Geopolymer Concrete Composites: A State-of-the-Art Review. SUSTAINABILITY 2021. [DOI: 10.3390/su132413502] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The building industry, which emits a significant quantity of greenhouse gases, is under tremendous pressure due to global climate change and its consequences for communities. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is an eco-friendly construction material that uses industrial or agricultural by-product ashes as the principal binder instead of Portland cement. Fly ash, ground granulated blast furnace slag, rice husk ash, metakaolin, and palm oil fuel ash were all employed as binders in geopolymer concrete, with fly ash being the most frequent. The most important engineering property for all types of concrete composites, including geopolymer concrete, is the compressive strength. It is influenced by different parameters such as the chemical composition of the binder materials, alkaline liquid to binder ratio, extra water content, superplasticizers dosages, binder content, fine and coarse aggregate content, sodium hydroxide and sodium silicate content, the ratio of sodium silicate to sodium hydroxide, the concentration of sodium hydroxide (molarity), curing temperature, curing durations inside oven, and specimen ages. In order to demonstrate the effects of these varied parameters on the compressive strength of the fly ash-based geopolymer concrete, a comprehensive dataset of 800 samples was gathered and analyzed. According to the findings, the curing temperature, sodium silicate content, and alkaline solution to binder ratio are the most significant independent parameters influencing the compressive strength of the fly ash-based geopolymer concrete (FA-BGPC) composites.
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Suresh Kumar A, Muthukannan M, Kanniga Devi R, Arunkumar K, Chithambar Ganesh A. Reduction of hazardous incinerated bio-medical waste ash and its environmental strain by utilizing in green concrete. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 84:2780-2792. [PMID: 34850693 DOI: 10.2166/wst.2021.239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Incinerated Bio-Medical Waste Ash (IBWA) is toxic waste material with broad potential (cancer, genetic risk, premature death, permanent disease) to inflict severe health damage for the atmosphere and humans. This waste is disposed of as landfill, which contaminates the underground water and environment. The effective way of disposal of IBWA is by utilizing it as a building material, which can reduce the hazardous toxic materials. The use of Geopolymer Concrete (GPC) combined with IBWA as a substitute for Ground Granulated Blast Furnace Slag (GGBS) has been researched for its ability to create a new type of Green Concrete. The physical and chemical properties were observed for the raw materials. IBWA was used at 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50% replacement by weight for GGBS. Mixing proportions were 1:2.21:3.48 respectively for GGBS, Manufacturing Sand (M-sand), and coarse aggregate. Fresh properties and mechanical properties were examined for all specimens. The findings show an increase in the setting time and flow of concrete and a decrease in density with improved utilization of IBWA. On the other hand, IBWA replacement for GGBS enhanced the mechanical properties. These results revealed that IBWA could be partially replaced as source material for Geopolymer Concrete. This research may contribute to the reduction of dangerous IBWA as a building material.
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Affiliation(s)
- A Suresh Kumar
- Department of Civil Engineering, Kalasalingam Academy of Research and Education, Krishnankoil, Tamil Nadu, India E-mail:
| | - M Muthukannan
- Department of Civil Engineering, Kalasalingam Academy of Research and Education, Krishnankoil, Tamil Nadu, India E-mail:
| | - R Kanniga Devi
- Department of Computer Science and Engineering, Kalasalingam Academy of Research and Education, Krishnankoil, Tamil Nadu, India
| | - K Arunkumar
- Department of Civil Engineering, Kalasalingam Academy of Research and Education, Krishnankoil, Tamil Nadu, India E-mail:
| | - A Chithambar Ganesh
- Department of Civil Engineering, Sree Vidyanikethan Engineering College, Tirupati, Andhra Pradesh, India
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13
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El-Wafa MA, Fukuzawa K. Optimization of Alkali-Activated Municipal Slag Composite Performance by Substituting Varying Ratios of Fly Ash for Fine Aggregate. MATERIALS 2021; 14:ma14216299. [PMID: 34771824 PMCID: PMC8585269 DOI: 10.3390/ma14216299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022]
Abstract
This study investigates the effect of varying ratios of fly ash as a partial replacement for fine aggregate on the performance of alkali-activated municipal slag composites. The strength and other properties of alkali-activated cementitious material (AACM) composites can be optimized by selecting the appropriate mix proportion. In this study, we used fly ash as a substitute for fine aggregate (FA/S) at varying ratios of 0.0, 5.0, 10.0, 15.0, 20.0, 25.0, and 30.0%, mixed with 50% water (W/SL), and 20% alkali activator (AL/SL) content instead of municipal slag (SL) as a core binder, cured in steam conditions. The effects of these substitutions on the initial mixing temperature, slump flow, compressive and splitting tensile strengths, and microstructure analysis of composites cured in steam conditions were investigated at 1, 7, 28, and 91 days. The evaluation of the experimental results revealed that increasing the ratio of fly ash substitution to fine aggregate by up to 20.0% led to a higher strength attributable to the composites, whereas when the extra substitution ratio of FA/S ranged from 25.0–30.0%, significant decreases in strength were observed. The composites’ strengths were estimated using the ACI 209 and ACI 318 design equations and compared to the measured strengths.
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Affiliation(s)
- Mahmoud Abo El-Wafa
- Department of Civil Engineering, Faculty of Engineering-Rabigh Branch, King, Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Civil Engineering, Faculty of Engineering, Aswan University, Aswan 81542, Egypt
- Correspondence:
| | - Kimio Fukuzawa
- Department of Urban and Civil Engineering, Ibaraki University, Hitachi 316-8511, Japan;
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14
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Fabrication of Low-Temperature Sintering Building Bricks Using Drilling Cutting and Geopolymeric Technology. MATERIALS 2021; 14:ma14205940. [PMID: 34683533 PMCID: PMC8540455 DOI: 10.3390/ma14205940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Abstract
This study explores the practicability of using drill cutting (DC) as raw material to fabricate building bricks through the high-temperature sintering method and low-temperature geopolymeric setting (LTGS) process. Drilling mud can be recycled and reutilized after certain treatment procedures and is considered as a non-hazardous waste. However, the treatment process is time-consuming and not cost-effective. For the sintering method, low porosity and high mechanical strength bricks can be sintered at temperatures above 800 °C and meet CNS standards. For the low-temperature geopolymeric setting process, sodium silicate was selected as an activating agent for geopolymerization of drill cutting. Several process parameters, such as Si2O/Na2O modulus of alkali solution and low-temperature geopolymeric setting temperature, were investigated. The physical and mechanical properties of the fabricated brick were evaluated. According to the test results, 72.4 MPa compressive strength building bricks with low porosity (13.9%) and water absorption (6.0%) can be fabricated with 2.0 Si2O/Na2O alkali solution at 500 °C. The drill cutting brick fabricated not only meets the CNS 382.R2002 common brick standard, but also solve its disposal problem.
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15
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Development of Waste-Based Alkali-Activated Cement Composites. MATERIALS 2021; 14:ma14195815. [PMID: 34640211 PMCID: PMC8510189 DOI: 10.3390/ma14195815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 11/17/2022]
Abstract
Nowadays, global warming and the ensuing climate change are one of the biggest problems for humanity, but environmental pollution and the low ratio of waste management and recycling are not negligible issues, either. By producing alkali-activated cements (AACs), it is possible to find an alternative way to handle the above-mentioned environmental problems. First, with a view to optimizing experimental parameters, metakaolin-based AACs were prepared, and in it, waste tire rubber was used as sand replacement (5–45 wt %). Insufficient wetting between the rubber particles and the matrix was corrected through different surface treatments of the rubber. For improving the mechanical/strength properties of the specimens, fibrous waste kaolin wool (0.5–1.5 wt %) was added to the AAC matrix. Considering the results of model experiments with metakaolin, blast-furnace-slag-based AAC composites were developed. The effects of storage conditions, specimen size and cyclic loading on the compressive strength were investigated, and the resulting figures were compared with the relevant values of classic binders. The strength (44.0 MPa) of the waste-based AAC composite significantly exceeds the required value (32.5 MPa) of clinker saving slag cement. Furthermore, following cyclic compressive loading, the residual strength of the waste-based AAC composite shows a slight increase rather than a decrease.
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16
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Effects of Mechanical Activation on Physical and Chemical Characteristics of Coal-Gasification Slag. COATINGS 2021. [DOI: 10.3390/coatings11080902] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Coal-gasification slag (CGS) was subjected to mechanical grinding by three different methods. We studied the effects of mechanical activation on various physical and chemical characteristics of the CGS, including particle-size distribution, specific surface area, mineral composition, degree of crystallinity, particle morphology, chemical bonding, surface activity and binding energy, anionic-polymerization degree and hydration properties. The results show that there are different effects on CGS characteristics depending on the type of activation applied. Mechanical activation also can increase the specific surface area and the dissolution rates of activated SiO2 and Al2O3, and the major elements (O, Si, Al, Ca) in CGS, whereas the degree of crystallinity and of polymerization of [SiO4] and [AlO6] are reduced by mechanical activation. We also found that the effects of different mechanical-activation methods on the compressive strength and activity were similar and could accelerate the hydration process.
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17
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Effect of Activating Solution Modulus on the Synthesis of Sustainable Geopolymer Binders Using Spent Oil Bleaching Earths as Precursor. SUSTAINABILITY 2021. [DOI: 10.3390/su13137501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The valorization of spent oil bleaching earths (SOBE) is crucial for the protection of the environment and the reuse of resources. In this research, alkali-activated binders were manufactured at room temperature using SOBE as a precursor by varying the mass ratio between the activating solutions of sodium silicate (Na2SiO3) and 6 M sodium hydroxide (NaOH) (activating solution modulus) (Na2SiO3/NaOH ratio = 1/1; 1/2; 1/3; 1/4) to investigate the influence on the technological properties of the materials. This process intends to evaluate the potential of SOBE, heat-treated at 550 °C (1 h), as a precursor of the reaction (source of aluminosilicates). Samples produced with higher amounts of sodium silicate developed a denser structure, with lower porosity and a higher amount of geopolymer gel. Maximum flexural (8.35 MPa) and compressive (28.4 MPa) strengths of samples cured at room temperature for 28 days were obtained with a Na2SiO3/NaOH mass ratio of 1/1. The study demonstrates that SOBE waste can be used as a precursor in the manufacture of geopolymer binders that show a good compromise between physical, mechanical and thermally insulating characteristics.
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18
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Öz HÖ, Doğan-Sağlamtimur N, Bilgil A, Tamer A, Günaydin K. Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics. MATERIALS 2021; 14:ma14112935. [PMID: 34072388 PMCID: PMC8199198 DOI: 10.3390/ma14112935] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/11/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022]
Abstract
This study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from Çatalağzı (FA) and İsken Sugözü (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 °C and 100 °C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 °C for the FB.
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Affiliation(s)
- Hatice Öznur Öz
- Department of Civil Engineering, Niğde Ömer Halisdemir University, Niğde 51240, Turkey;
- Correspondence: ; Tel.: +90-388-225-27-96
| | | | - Ahmet Bilgil
- Department of Civil Engineering, Niğde Ömer Halisdemir University, Niğde 51240, Turkey;
| | - Aykut Tamer
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK;
| | - Kadir Günaydin
- Department of Aerospace Science and Technology, Politecnico di Milano, 20156 Milano, Italy;
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19
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Shehata N, Sayed ET, Abdelkareem MA. Recent progress in environmentally friendly geopolymers: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143166. [PMID: 33190897 DOI: 10.1016/j.scitotenv.2020.143166] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 09/08/2020] [Accepted: 10/14/2020] [Indexed: 05/12/2023]
Abstract
The manufacturing of cement demand burning of huge quantities of fuel as well as significant emissions of CO2 resulting from the decomposition of limestone that consequently resulted in severe environmental impact that is estimated by one ton of CO2 per ton of cement. Geopolymerization technology is an effective method for converting wastes (containing alumina and silica) into useful products. It can reduce CO2 emissions significantly from the cement industry. The geopolymerization process usually starts with source materials based on alumina/silicate in addition to alkaline liquids. The compressive strength, setting time, and workability of the final product depends mainly on the type and proportions of the precursors, the type and strength of the activator, the mixing and curing conditions. The structural performance of a geopolymer is similar to that of ordinary Portland cement (OPC). Therefore, geopolymer can replace OPC, and thus decreasing the energy consumption, reducing the cost of the building materials, and minimizing the environmental impacts of the cement industry. This review summaries the mechanism of geopolymerization, including the controlling parameters and different raw materials (fly ash, kaolinite and metakaolin, slag, red mud, silica waste, heavy metals waste, and others) with particular focus on recent studies and challenges in this area.
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Affiliation(s)
- Nabila Shehata
- Environmental Science and Industrial Development Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University, Beni-Suef, Egypt.
| | - Enas Taha Sayed
- Center for Advanced Materials Research, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates; Chemical Engineering Department, Minia University, Elminia, Egypt
| | - Mohammad Ali Abdelkareem
- Center for Advanced Materials Research, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates; Chemical Engineering Department, Minia University, Elminia, Egypt; Department of Sustainable and Renewable Energy Engineering, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates
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20
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Ghafoor MT, Khan QS, Qazi AU, Sheikh MN, Hadi M. Influence of alkaline activators on the mechanical properties of fly ash based geopolymer concrete cured at ambient temperature. CONSTRUCTION AND BUILDING MATERIALS 2021; 273:121752. [DOI: 10.1016/j.conbuildmat.2020.121752] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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21
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Ren B, Zhao Y, Bai H, Kang S, Zhang T, Song S. Eco-friendly geopolymer prepared from solid wastes: A critical review. CHEMOSPHERE 2021; 267:128900. [PMID: 33234306 DOI: 10.1016/j.chemosphere.2020.128900] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/22/2020] [Accepted: 11/04/2020] [Indexed: 05/10/2023]
Abstract
Solid wastes are generated from human activities which could cause damage to the ecological environment and human beings. In recent years, there has been extensive research on solid wastes utilized as precursors, aggregates, fibers, etc. to prepare the geopolymers, which has invariably been a research hotspot. This review classifies the solid wastes utilized for geopolymers into three main categories: industrial waste, agricultural waste, and municipal waste. Accordingly, we systematically dissert solid wastes-based geopolymer from the perspectives of structure, properties, and application. The chemical composition, morphology, particle size, thermal conductivity, and other characteristics of solid wastes can trigger changes in the specific properties of geopolymers. On this account, solid wastes-based geopolymers have great potential in the domain of concrete, fireproof materials, impermeable materials, catalysts, adsorbents, and energy storage materials, etc. More importantly, geopolymers have obvious advantages in immobilizing heavy metals in solid wastes. Therefore, it can demonstrate geopolymer is a sustainable and environmentally friendly "green material". However, it still confronts the challenges of solid wastes utilized in geopolymer (technology, economy, administration). It requires the government, enterprises, and the public to work together for co-governance to accomplish industrialization and commercialization of solid wastes-based geopolymer.
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Affiliation(s)
- Bo Ren
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China
| | - Yunliang Zhao
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China.
| | - Haoyu Bai
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China
| | - Shichang Kang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China
| | - Tingting Zhang
- School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China
| | - Shaoxian Song
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei, 430070, China
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22
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Silva GJB, Santana VP, Wójcik M. Investigation on mechanical and microstructural properties of alkali-activated materials made of wood biomass ash and glass powder. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2020.09.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Carbonation and Chloride Ions' Penetration of Alkali-Activated Materials: A Review. MOLECULES (BASEL, SWITZERLAND) 2020; 25:molecules25215074. [PMID: 33139641 PMCID: PMC7662611 DOI: 10.3390/molecules25215074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 11/16/2022]
Abstract
Alkali-activated materials (AAMs) are widely recognized as potential alternatives to ordinary Portland cement (OPC) due to their lower carbon footprint. However, like OPC, AAMs can also generate some durable problems when exposed to aggressive environments and the mechanisms and possible improvements are still not fully clear in existing investigations. Furthermore, the corrosion mechanisms of AAMs are different from OPC due to the discrepant reaction products and pore structures. Thus, this study’s aim is to review the chemical reaction mechanisms, factors, and mitigation methods when AAMs are attacked by carbonation and chloride ions, along with a summative discussion regarding instructive insights to durable problems of AAMs.
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24
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Solouki A, Viscomi G, Lamperti R, Tataranni P. Quarry Waste as Precursors in Geopolymers for Civil Engineering Applications: A Decade in Review. MATERIALS 2020; 13:ma13143146. [PMID: 32679685 PMCID: PMC7411772 DOI: 10.3390/ma13143146] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/02/2020] [Accepted: 07/13/2020] [Indexed: 11/16/2022]
Abstract
Carbon footprint reduction of paving materials could be explored through recycling mining by-products into different applications, which will preserve natural resources and decrease environmental issues. One possible approach is to reuse quarry dust and mining ore waste as precursors in geopolymer applications. geopolymers are mineral polymers rich in aluminosilicates with an amorphous to a semi-crystalline three-dimensional structure. The current review aims to summarize the studies conducted during the past decade on geopolymers containing quarry dust and mine tailings. The first section discusses various precursors used for geopolymer cement production such as metakaolin, ground granulated blast furnace slag (GGBFS), fly ash, and quarry/mining ore wastes including silt, tungsten, vanadium, copper, gold, zinc, marble, iron, basalt, and lithium. Different calcination treatments and curing conditions have been summarized. In some cases, the precursors are required to be calcined to increase their reactivity. Both ambient temperature and elevated temperature curing conditions have been summarized. Less attention has been paid to room temperature curing, which is necessary for field and industrial implementations. Engineering properties such as compressive strength, density, durability and acid resistance, water absorption and abrasion of geopolymers containing mining waste were reviewed. One of the main barriers preventing the widespread use of waste powders, in addition to economic aspects, in geopolymers could be due to their unstable chemical structure. This was shown through extensive leachate of Na+ or K+ cations in geopolymer structures. The review of over 100 articles indicated the need for further research on different aspects of quarry waste geopolymer productions before its full industrial implementation.
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Affiliation(s)
- Abbas Solouki
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, 40136 Bologna, Italy;
- SAPABA, 40037 Pontecchio Marconi BO, Italy;
- Correspondence:
| | | | | | - Piergiorgio Tataranni
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, 40136 Bologna, Italy;
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25
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Setting and Hardening Behaviour of Alkali-Activated Landfilled Fly Ash-Slag Binder at Room Temperature. MATERIALS 2020; 13:ma13143130. [PMID: 32674297 PMCID: PMC7411941 DOI: 10.3390/ma13143130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 11/17/2022]
Abstract
A geopolymer is normally considered an environmentally friendly binder due to the utilisation of industrial wastes. This study focusses on the potential of geopolymer preparation at room temperature from landfilled fly ash (LFA) which has been discharged to the land for more than three years. To accelerate the reaction process, 20–30 wt.% LFA was replaced by ground-granulated blast-furnace slag (GGBS). The effect of water glass modulus, Na2O content, water-to-solid ratio, and GGBS content on the setting time and strength development of the binder was discussed. Results showed that to activate LFA, the optimal value of the sodium silicate modulus for alkaline solution was 1.4–1.6 with a Na2O content of 10%, and the water-to-solid ratio was 0.4. In addition, the setting time of the binder reduced with increasing content of GGBS replacement, and the compressive strength increased due to the coexistence of C–(A)–S–H and zeolite-like phases. The maximum compressive strength of the binder was 29.2 MPa after 56 days of curing. The relatively low strength was likely due to the absence of the Q4 unit with a three-dimensional structure.
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26
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Komljenović M, Tanasijević G, Džunuzović N, Provis JL. Immobilization of cesium with alkali-activated blast furnace slag. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:121765. [PMID: 31928790 DOI: 10.1016/j.jhazmat.2019.121765] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/24/2019] [Accepted: 11/27/2019] [Indexed: 06/10/2023]
Abstract
Alkali-activated binders (AABs), as a promising alternative to Portland cement, are now being used on a commercial scale in various applications around the world, including hazardous and radioactive waste immobilization. In this paper, the leaching resistance, strength, and nanostructural alteration of alkali-activated blast furnace slag (AABFS) doped with 2 % and 5 % cesium were investigated. The addition of cesium caused a significant increase in the compressive strength of AABFS, followed by mild strength reduction after leaching. AABFS can be considered a potentially efficient matrix for cesium immobilization, since the mean leachability index in both cases (2 % and 5 % of Cs added) was above the threshold value of 6. Both doping with Cs and leaching caused the transformation of the AABFS nanostructure. The majority of the aluminum that was released from the C-A-S-H gel due to leaching remained within the AABFS matrix, initiating gel reconstruction: the C-A-S-H gel was converted to C-S-H gel, and an additional N-(C)-A-S-H gel was also formed. Cesium was preferentially associated with the N-(C)-A-S-H gel rather than with the C-A-S-H gel. The results of this research seem to be in good agreement with the Cross-linked Substituted Tobermorite Model (CSTM).
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Affiliation(s)
- M Komljenović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
| | - G Tanasijević
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - N Džunuzović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
| | - J L Provis
- Department of Materials Science and Engineering, University of Sheffield, Mappin St, Sheffield S1 3JD, United Kingdom
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27
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Effect of Alkali Concentration on the Activation of Carbonate-High Illite Clay. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study explores the effect of activating solution concentration (4, 6 and 8 M NaOH) on mechanically and thermally pre-treated carbonate-high illite clay (LCR). Pastes were prepared with an alkaline solution/clay (S/B) ratio of 0.55, which were cured at room temperature and relative humidity > 90% in a climatic chamber. At two and 28 days, compressive mechanical strength was determined, and the reaction products were characterised by X-ray Powder Diffraction analysis (XRPD), Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy - Energy Dispersive X-ray spectroscopy (SEM/EDX). Results obtained showed that the presence of reactive calcium in the starting clay induces co-precipitation of a mix of gels: An aluminium-enriched C-S-H gel (C-A-S-H) and a N-A-S-H gel, in which sodium is partially replaced by calcium (N,C)-A-S-H. Pastes prepared with higher (6 or 8 M) activator concentrations exhibit a more compact matrix than the ones prepared with 4 M NaOH. The findings show that the use of a 6 M NaOH solution yields a binder with two days compressive strength >20 MPa and 28 days strength of over 30 MPa.
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28
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Bong SH, Nematollahi B, Nazari A, Xia M, Sanjayan J. Efficiency of Different Superplasticizers and Retarders on Properties of 'One-Part' Fly Ash-Slag Blended Geopolymers with Different Activators. MATERIALS 2019; 12:ma12203410. [PMID: 31635266 PMCID: PMC6829244 DOI: 10.3390/ma12203410] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/07/2019] [Accepted: 10/11/2019] [Indexed: 11/16/2022]
Abstract
Currently, there are a very limited number of studies on the effect of admixtures on properties of 'one-part' geopolymers. This paper reports the effects of different superplasticizers and retarders on fresh and hardened properties of one-part fly ash-slag blended geopolymers made by different solid activators. Two different grades of sodium silicate, namely anhydrous sodium metasilicate powder (nSiO2/nNa2O = 0.9) and GD Grade sodium silicate powder (nSiO2/nNa2O = 2.0) were used as the solid activators. Five different commercially available superplasticizers, including three modified polycarboxylate-based superplasticizers (denoted as PC1, PC2, and PC3) and two naphthalene-based superplasticizers (denoted as N1 and N2), as well as three different retarders, including sucrose, anhydrous borax and a commercially available retarder, were investigated. Workability, setting time and compressive strength of the mixtures without and with addition of each 'individual' admixture were measured. The results showed the effect of admixtures on the properties of the one-part geopolymers significantly depended on the type of solid activator and the type of admixture used. When GD Grade sodium silicate powder was used as the solid activator, all investigated admixtures not only had no positive effect on the workability and setting time, but also significantly reduced the compressive strength of the mixture. However, when anhydrous sodium metasilicate powder was used as the solid activator, the PC1 and sucrose were the best performing superplasticizer and retarder, respectively, causing no reduction in the compressive strength, but significant increase in the workability (up to + 72%) and setting time (up to + 111%), respectively as compared to the mixture with no admixture. In addition, the results also showed that addition of 'combined' admixtures (i.e., PC1 in the presence of sucrose) significantly increased the workability (up to + 39%) and setting time (up to + 141%), but slightly reduced the compressive strength (-16%) of the mixture activated by anhydrous sodium metasilicate powder, as compared to the mixture with no admixture.
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Affiliation(s)
- Shin Hau Bong
- Centre for Smart Infrastructure and Digital Construction, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
| | - Behzad Nematollahi
- Centre for Smart Infrastructure and Digital Construction, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
| | - Ali Nazari
- Centre for Smart Infrastructure and Digital Construction, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
| | - Ming Xia
- Centre for Smart Infrastructure and Digital Construction, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
| | - Jay Sanjayan
- Centre for Smart Infrastructure and Digital Construction, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
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Mix Design and Mechanical Properties of Fly Ash and GGBFS-Synthesized Alkali-Activated Concrete (AAC). INFRASTRUCTURES 2019. [DOI: 10.3390/infrastructures4020020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cement is one of the construction materials widely used around the world in order to develop infrastructure and it is also one of the factors affecting economies. The production of cement consumes a lot of raw materials like limestone, which releases CO2 into the atmosphere and thus leads to global warming. Many investigations are underway in this area, essentially focusing on the eco-accommodating environment. In the research, an alternative material to cement binder is geopolymer binder, with the same efficiency. This paper presents scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis of factory byproducts (i.e., fly ash and ground granulated blast furnace slag (GGBFS)). The mix design process for the manufacture of alkali-activated geopolymer binders synthesized by fly ash and GGBFS is presented. The mechanical properties (compression, split tensile and flexural strength, bond strength) of geopolymer concrete at different mix proportions and at dissimilar curing conditions were also investigated. Geopolymer concrete synthesized with 30% fly ash and 70% GGBFS has better properties at 14 M of NaOH and cured in an oven for 24 h at 70 °C.
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Bong SH, Nematollahi B, Nazari A, Xia M, Sanjayan J. Method of Optimisation for Ambient Temperature Cured Sustainable Geopolymers for 3D Printing Construction Applications. MATERIALS 2019; 12:ma12060902. [PMID: 30889855 PMCID: PMC6470972 DOI: 10.3390/ma12060902] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 11/16/2022]
Abstract
Since the initial introduction of geopolymers, these materials have been characterised as environmentally-friendly sustainable substitutes for ordinary Portland cement (OPC). There is a routine increase in the application of geopolymers, especially in advanced technologies. Because of its better rheological characteristics compared to OPC, geopolymers are appropriate materials for extrusion-based 3D printing technologies. This paper focuses on the optimisation of an ambient temperature cured geopolymer for 3D printing construction applications. The effects of mixture parameters, including the type of hydroxide solution (HS), the type of silicate solution (SS) and the mass ratio of SS to HS on the workability, extrudability, shape retention ability and mechanical performance of different geopolymer mixtures were investigated. Accordingly, an optimum mixture was identified for geopolymers cured at ambient temperatures. Mechanical properties of the optimised mixture, including flexural and compressive strengths, were measured in different directions with respect to the printed layers. Further, uniaxial tension tests were also conducted on the optimised mixture to measure its interlayer bond strength. The results showed that among the activators investigated, the sodium-based activator composed of sodium hydroxide and sodium silicate solutions, with a SiO₂/Na₂O ratio of 3.22, was the most effective activator, providing appropriate workability and extrudability, along with reasonable strength and a high shape retention ability. The acquired mechanical properties exhibited anisotropic behaviour in different testing direction. The strength of the interlayer bond was found to be adequate to avoid interfacial shear failure.
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Affiliation(s)
- Shin Hau Bong
- Centre for Sustainable Infrastructure, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 3122 Melbourne, Australia.
| | - Behzad Nematollahi
- Centre for Sustainable Infrastructure, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 3122 Melbourne, Australia.
| | - Ali Nazari
- Centre for Sustainable Infrastructure, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 3122 Melbourne, Australia.
| | - Ming Xia
- Centre for Sustainable Infrastructure, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 3122 Melbourne, Australia.
| | - Jay Sanjayan
- Centre for Sustainable Infrastructure, Faculty of Science, Engineering and Technology, Swinburne University of Technology, 3122 Melbourne, Australia.
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31
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Glass-Ceramic Foams from 'Weak Alkali Activation' and Gel-Casting of Waste Glass/Fly Ash Mixtures. MATERIALS 2019; 12:ma12040588. [PMID: 30781417 PMCID: PMC6416607 DOI: 10.3390/ma12040588] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/25/2019] [Accepted: 02/12/2019] [Indexed: 11/21/2022]
Abstract
A ‘weak alkali activation’ was applied to aqueous suspensions based on soda lime glass and coal fly ash. Unlike in actual geopolymers, an extensive formation of zeolite-like gels was not expected, due to the low molarity of the alkali activator (NaOH) used. In any case, the suspension underwent gelation and presented a marked pseudoplastic behavior. A significant foaming could be achieved by air incorporation, in turn resulting from intensive mechanical stirring (with the help of a surfactant), before complete hardening. Dried foams were later subjected to heat treatment at 700–900 °C. The interactions between glass and fly ash, upon firing, determined the formation of new crystal phases, particularly nepheline (sodium alumino–silicate), with remarkable crushing strength (~6 MPa, with a porosity of about 70%). The fired materials, finally, demonstrated a successful stabilization of pollutants from fly ash and a low thermal conductivity that could be exploited for building applications.
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32
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Karanac M, Đolić M, Veličković Z, Kapidžić A, Ivanovski V, Mitrić M, Marinković A. Efficient multistep arsenate removal onto magnetite modified fly ash. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 224:263-276. [PMID: 30055459 DOI: 10.1016/j.jenvman.2018.07.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/07/2018] [Accepted: 07/15/2018] [Indexed: 06/08/2023]
Abstract
The modification of the fly ash (FA) by magnetite (M) was performed to obtain FAM adsorbent with improved adsorption efficiency for arsenate removal from water. The novel low cost adsorbents are characterized by liquid nitrogen porosimetry (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MB) and Fourier transform infrared (FTIR) spectroscopy. The optimal conditions and key factors influencing the adsorbent synthesis are assessed using the response surface method (RSM). The adsorption experiment was carried out in a batch system by varying the contact time, temperature, pH, and mass of the adsorbent. The adsorption capacity of the FAM adsorbent for As(V), calculated by Langmuir model, was 19.14 mg g-1. The thermodynamic parameters showed spontaneity of adsorption with low endothermic character. The kinetic data followed the pseudo-second-order kinetic model (PSO), and Weber-Morris model indicated intra-particle diffusion as rate limiting step. Alternative to low desorption capability of the FAM was found by five consecutive adsorption/magnetite precipitation processes which gave exhausted layered adsorbent with 65.78 mg g-1 capacity. This research also has shed light on the mechanism of As(V)-ion adsorption, presenting a promising solution for the valorization of a widely abundant industrial waste.
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Affiliation(s)
- Milica Karanac
- Innovation Center of the Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia.
| | - Maja Đolić
- Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | - Zlate Veličković
- Military Academy, University of Defence, General Pavle Jurišić - Šturm 33, 11000 Belgrade, Serbia
| | - Ana Kapidžić
- Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | - Valentin Ivanovski
- Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | - Miodrag Mitrić
- Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | - Aleksandar Marinković
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia
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Yahya Z, Abdullah MMAB, Talib SZA, Razak RA. Comparative study on early strength of sodium hydroxide (NaOH) activated fly ash based geopolymer. AIP CONFERENCE PROCEEDINGS 2017. [DOI: 10.1063/1.5003542] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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34
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Sun Y, Qi G, Lei X, Xu H, Wang Y. Extraction of Uranium in Bottom Ash Derived from High-Germanium Coals. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.proenv.2016.02.096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Peng K, Yang H, Ouyang J. Tungsten tailing powders activated for use as cementitious material. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2015.09.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Shu Y, Wei X, Fang Y, Lan B, Chen H. Removal of sulfuric acid mist from lead-acid battery plants by coal fly ash-based sorbents. JOURNAL OF HAZARDOUS MATERIALS 2015; 286:517-524. [PMID: 25603301 DOI: 10.1016/j.jhazmat.2015.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 01/03/2015] [Accepted: 01/05/2015] [Indexed: 06/04/2023]
Abstract
Sorbents from coal fly ash (CFA) activated by NaOH, CaO and H2O were prepared for H2SO4 mist removal from lead-acid battery plants. The effects of parameters including temperature, time, the ratios of CFA/activator and water/solid during sorbent preparation were investigated. It is found that the synthesized sorbents exhibit much higher removal capacity for H2SO4 mist when compared with that of raw coal fly ash and CaO except for H2O activated sorbent and this sorbent was hence excluded from the study because of its low capacity. The H2SO4 mist removal efficiency increases with the increasing of preparation time length and temperature. In addition, the ratios of CFA/activator and water/solid also impact the removal efficiency, and the optimum preparation conditions are identified as: a water/solid ratio of 10:1 at 120 °C for 10h, a CFA:CaO weight ratio of 10:1, and a NaOH solution concentration of 3 mol/L. The formation of rough surface structure and an increased surface area after NaOH/CaO activation favor the sorption of H2SO4 mist and possible sorption mechanisms might be electrostatic attractions and chemical precipitation between the surface of sorbents and H2SO4 mist.
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Affiliation(s)
- Yuehong Shu
- School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
| | - Xiangyu Wei
- School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China
| | - Yu Fang
- Sirio Pharma Co., Ltd Shantou 515041, China
| | - Bingyan Lan
- School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China
| | - Hongyu Chen
- School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China
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37
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Bădănoiu AI, Abood Al-Saadi TH, Voicu G. Synthesis and properties of new materials produced by alkaline activation of glass cullet and red mud. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.minpro.2014.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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38
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Marjanović N, Komljenović M, Baščarević Z, Nikolić V. Comparison of Two Alkali-activated Systems: Mechanically Activated Fly Ash and fly Ash-blast Furnace Slag Blends. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.proeng.2015.06.142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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39
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The effect of different parameters on the development of compressive strength of oil palm shell geopolymer concrete. ScientificWorldJournal 2014; 2014:898536. [PMID: 25531006 PMCID: PMC4228731 DOI: 10.1155/2014/898536] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 08/27/2014] [Indexed: 11/17/2022] Open
Abstract
This paper presents the experimental results of an on-going research project on geopolymer lightweight concrete using two locally available waste materials--low calcium fly ash (FA) and oil palm shell (OPS)--as the binder and lightweight coarse aggregate, respectively. OPS was pretreated with three different alkaline solutions of sodium hydroxide (NaOH), potassium hydroxide, and sodium silicate as well as polyvinyl alcohol (PVA) for 30 days; afterwards, oil palm shell geopolymer lightweight concrete (OPSGPC) was cast by using both pretreated and untreated OPSs. The effect of these solutions on the water absorption of OPS, and the development of compressive strength in different curing conditions of OPSGPC produced by pretreated OPS were investigated; subsequently the influence of NaOH concentration, alkaline solution to FA ratio (A/FA), and different curing regimes on the compressive strength and density of OPSGPC produced by untreated OPS was inspected. The 24-hour water absorption value for OPS pretreated with 20% and 50% PVA solution was about 4% compared to 23% for untreated OPS. OPSGPC produced from OPS treated with 50% PVA solution produced the highest compressive strength of about 30 MPa in ambient cured condition. The pretreatment with alkaline solution did not have a significant positive effect on the water absorption of OPS aggregate and the compressive strength of OPSGPC. The result revealed that a maximum compressive strength of 32 MPa could be obtained at a temperature of 65°C and curing period of 4 days. This investigation also found that an A/FA ratio of 0.45 has the optimum amount of alkaline liquid and it resulted in the highest level of compressive strength.
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40
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Noli F, Buema G, Misaelides P, Harja M. New materials synthesized from ash under moderate conditions for removal of toxic and radioactive metals. J Radioanal Nucl Chem 2014. [DOI: 10.1007/s10967-014-3762-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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Affiliation(s)
- Y. C. Wang
- College of Materials and Mineral ResourcesXi’an University of Architecture and Technology, Xi’an, China
| | - Y. J. Zhang
- College of Materials and Mineral ResourcesXi’an University of Architecture and Technology, Xi’an, China
| | - D. L. Xu
- College of Materials and Mineral ResourcesXi’an University of Architecture and Technology, Xi’an, China
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42
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Shi XS, Collins FG, Zhao XL, Wang QY. Mechanical properties and microstructure analysis of fly ash geopolymeric recycled concrete. JOURNAL OF HAZARDOUS MATERIALS 2012; 237-238:20-29. [PMID: 22954605 DOI: 10.1016/j.jhazmat.2012.07.070] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 07/06/2012] [Accepted: 07/08/2012] [Indexed: 06/01/2023]
Abstract
Six mixtures with different recycled aggregate (RA) replacement ratios of 0%, 50% and 100% were designed to manufacture recycled aggregate concrete (RAC) and alkali-activated fly ash geopolymeric recycled concrete (GRC). The physical and mechanical properties were investigated indicating different performances from each other. Optical microscopy under transmitted light and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) were carried out in this study in order to identify the mechanism underlying the effects of the geopolymer and RA on concrete properties. The features of aggregates, paste and interfacial transition zone (ITZ) were compared and discussed. Experimental results indicate that using alkali-activated fly ash geopolymer as replacement of ordinary Portland cement (OPC) effectively improved the compressive strength. With increasing of RA contents in both RAC and GRC, the compressive strength decreased gradually. The microstructure analysis shows that, on one hand, the presence of RA weakens the strength of the aggregates and the structure of ITZs; on the other hand, due to the alkali-activated fly ash in geopolymer concrete, the contents of Portlandite (Ca(OH)(2)) and voids were reduced, as well as improved the matrix homogeneity. The microstructure of GRC was changed by different reaction products, such as aluminosilicate gel.
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Affiliation(s)
- X S Shi
- College of Architecture and Environment, Sichuan University, Chengdu, PR China
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Komljenović MM, Baščarević Z, Marjanović N, Nikolić V. Decalcification resistance of alkali-activated slag. JOURNAL OF HAZARDOUS MATERIALS 2012; 233-234:112-121. [PMID: 22818592 DOI: 10.1016/j.jhazmat.2012.06.063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 06/06/2012] [Accepted: 06/29/2012] [Indexed: 06/01/2023]
Abstract
This paper analyses the effects of decalcification in concentrated 6M NH(4)NO(3) solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si ~0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.
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44
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Discussion on Properties and Microstructure of Geopolymer Concrete Containing Fly Ash and Recycled Aggregate. ACTA ACUST UNITED AC 2012. [DOI: 10.4028/www.scientific.net/amr.450-451.1577] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Construction materials dominate the main responsibility to maintain the environmental sustainable development in human’s activities. Geopolymer concrete containing fly ash and recycled aggregate is a new concrete which can reuse the by-product of power station and waste concrete, as well as reduce the production of cement which contribute a lot of carbon dioxide emission in the manufacturing process. In this paper, experiments were carried out to investigate the mechanical properties and microstructure of geopolymer concrete with different recycled aggregate contents. Six mixtures were designed including alkali-activated fly ash geopolymeric recycled concrete and corresponding ordinary concrete as the comparison. The compressive strength of the concrete with 0%, 50% and 100% recycled aggregates was tested. The microstructure of these concrete were investigated by petrographic microscope under transmit light. According to experimental results, the strength development and failure mechanism are discussed. Furthermore, the application of such geopolymer concrete is discussed and suggested.
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45
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Ferone C, Colangelo F, Cioffi R, Montagnaro F, Santoro L. Mechanical Performances of Weathered Coal Fly Ash Based Geopolymer Bricks. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.proeng.2011.11.2073] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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