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Cao W, Lv X, Ban J, Lu JX, Liu Z, Chen Z, Poon CS. High-efficient stabilization and solidification of municipal solid waste incineration fly ash by synergy of alkali treatment and supersulfated cement. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 355:124261. [PMID: 38815891 DOI: 10.1016/j.envpol.2024.124261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/05/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
Municipal solid waste incineration fly ash (IFA) designated as hazardous waste poses risks to environment and human health. This study introduces a novel approach for the stabilization and solidification (S/S) of IFA: a combined approach involving alkali treatment and immobilization in low-carbon supersulfated cement (SSC). The impact of varying temperatures of alkali solution on the chemical and mineralogical compositions, as well as the pozzolanic reactivity of IFA, and the removal efficiency of heavy metals and metallic aluminum (Al) were examined. The physical characteristics, hydration kinetics and effectiveness of SSC in immobilizing IFA were also analyzed. Results showed that alkali treatment at 25 °C effectively eliminated heavy metals like manganese (Mn), barium (Ba), nickel (Ni), and chromium (Cr) to safe levels and totally removed the metallic Al, while enhancing the pozzolanic reactivity of IFA. By incorporating the alkali-treated IFA and filtrate, the density, compressive strength and hydration reaction of SSC were improved, resulting in higher hydration degree, finer pore structure, and denser microstructure compared to untreated IFA. The rich presence of calcium-aluminosilicate-hydrate (C-(A)-S-H) and ettringite (AFt) in SSC facilitated the efficient stabilization and solidification of heavy metals, leading to a significant decrease in their leaching potential. The use of SSC for treating Ca(OH)2- and 25°C-treated IFA could achieve high strength and high-efficient immobilization.
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Affiliation(s)
- Wenxiang Cao
- Department of Civil and Environment Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xuesen Lv
- Department of Civil and Environment Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jiaxing Ban
- Department of Civil and Environment Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jian-Xin Lu
- Department of Civil and Environment Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Ze Liu
- School of Chemical and Environmental Engineering, China University of Mining & Technology, Beijing, 100083, China
| | - Zhen Chen
- State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Chi Sun Poon
- Department of Civil and Environment Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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Guo J, Lu X, Tian M. Modified phosphogypsum whiskers for decontamination of mercury tailings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:32416-32427. [PMID: 38649609 DOI: 10.1007/s11356-024-33385-9] [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: 11/22/2023] [Accepted: 04/15/2024] [Indexed: 04/25/2024]
Abstract
Mercury (Hg) tailings are hazardous solid wastes because of their high Hg concentrations. Modified phosphogypsum (PG) can decrease the bioactivity and mobility of heavy metals through chemisorption or electrostatic interactions. In this study, PG whiskers were modified by ZnCl2 and S, chitosan-hydrochloric acid, and thioglycolic materials; the resulting modified whiskers were used to decontaminate Hg tailings. Leaching tests and orthogonal experiments were conducted to optimize the modification parameters, including modifier quantity, pH, reaction temperature, and reaction time. The structure and physicochemical properties of the whiskers before and after modification were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The stabilization efficiency of the modified PG whiskers ranged from 93.05 to 97.50%, demonstrating excellent stabilization effects. The stabilization was achieved through chemisorption or complexation. The decontamination process using modified whiskers reduced the pH and total nitrogen of the tailings; increased the cation exchange, total phosphorus, organic carbon, and total carbon; and made the tailings suitable for planting. In addition, the modified PG promoted the morphological transformation of Hg in the tailings, thereby significantly decreasing the Hg content in the effective states and mitigating the risk of Hg contamination.
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Affiliation(s)
- Jinfa Guo
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Xuan Lu
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, 550025, People's Republic of China
| | - Mengkui Tian
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, 550025, People's Republic of China.
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Zhang Y, Fu P, Ni W, Zhang S, Li S, Deng W, Hu W, Li J, Pei F, Du L, Wang Y. A review of solid wastes-based stabilizers for remediating heavy metals co-contaminated soil: Applications and challenges. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170667. [PMID: 38331289 DOI: 10.1016/j.scitotenv.2024.170667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/27/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
The remediation of heavy metals/metalloids (HMs) co-contaminated soil by solid wastes-based stabilizers (SWBS) has received major concern recently. Based on the literature reported in the latest years (2010-2023), this review systematically summarizes the different types of solid wastes (e.g., steel slag, coal fly ash, red mud, and sewage sludge, etc.) employed to stabilize HMs contaminated soil, and presents results from laboratory and field experiments. Firstly, the suitable solid wastes for soil remediation are reviewed, and the pros and cons are presented. Thereafter, the technical feasibility and economic benefit are evaluated for field application. Moreover, evaluation methods for remediation of different types of HMs-contaminated soil and the effects of SWBS on soil properties are summarized. Finally, due to the large specific surface, porous structure, and high reactivity, the SWBS can effectively stabilize HMs via adsorption, complexation, co/precipitation, ion exchange, electrostatic interaction, redox, and hydration process. Importantly, the environmental implications and long-term effectiveness associated with the utilization of solid wastes are highlighted, which are challenges for practical implementation of soil stabilization using SWBS, because the aging of soil/solid wastes has not been thoroughly investigated. Future attention should focus on modifying the SWBS and establishing an integrated long-term stability evaluation method.
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Affiliation(s)
- Yuliang Zhang
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Pingfeng Fu
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of the Ministry of Education for Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China.
| | - Wen Ni
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of the Ministry of Education for Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China
| | - Siqi Zhang
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of the Ministry of Education for Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China
| | - Sheng Li
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wei Deng
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wentao Hu
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of the Ministry of Education for Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China
| | - Jia Li
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Fuyun Pei
- CECEP Tech and Ecology & Environment Co., Ltd., Shenzhen 518017, China
| | - Linfeng Du
- CECEP Tech and Ecology & Environment Co., Ltd., Shenzhen 518017, China
| | - Yueling Wang
- CECEP Tech and Ecology & Environment Co., Ltd., Shenzhen 518017, China
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Tang P, Javadi AA, Vinai R. Sustainable utilisation of calcium-rich industrial wastes in soil stabilisation: Potential use of calcium carbide residue. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 357:120800. [PMID: 38579471 DOI: 10.1016/j.jenvman.2024.120800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/07/2024]
Abstract
Calcium carbide residue (CCR), a by-product of the acetylene industry, is generated at a rate of 136 million tonnes per year, posing significant environmental risks. This review examines the potential utilisation of CCR in soil stabilisation, focusing on its stabilisation mechanism, performance in improving mechanical properties, environmental safety, and sustainability. The aim is to identify future research directions for CCR-based stabilisation to promote its broader application, and to provide references for managing similar Ca-rich wastes. CCR-based materials demonstrate promising benefits in enhancing various soil properties, such as uniaxial strength, swelling properties, triaxial shear behaviour, compressibility, and dynamic responses, while also reducing the mobility of contaminants. Compared to conventional stabilisers, CCR-based materials exhibit comparable performance in soil improvement, environmental impact and safety, and economic feasibility. However, further research is required to delve deeper into stabilisation mechanisms, mechanical properties, and stability of contaminants for the soil treated with CCR-based materials under diverse conditions.
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Affiliation(s)
- Panpan Tang
- Department of Engineering, University of Exeter, Exeter, United Kingdom.
| | - Akbar A Javadi
- Department of Engineering, University of Exeter, Exeter, United Kingdom
| | - Raffaele Vinai
- Department of Engineering, University of Exeter, Exeter, United Kingdom
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Sun C, Ge W, Zhang Y, Wang L, Xia Y, Lin X, Huang Q, Lu S, Tsang DCW, Yan J. Designing low-carbon cement-free binders for stabilization/solidification of MSWI fly ash. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 339:117938. [PMID: 37080097 DOI: 10.1016/j.jenvman.2023.117938] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Low-carbon and high-efficiency binder is desirable for sustainable treatment of municipal solid waste incineration fly ash (MSWI FA). In this study, CaO or MgO was used to activate ground granulated blast furnace slag (GGBS) to form calcium silicate hydrate and magnesium silica hydrate gel for stabilization/solidification of hazardous MSWI FA. Experimental results showed that potential toxic elements (PTEs), such as Pb and Zn, significantly inhibited the formation of reaction products in CaO-GGBS system due to the complexation between Ca(OH)2 and PTEs, whereas PTEs only had insignificant inhibition on transformation from MgO to Mg(OH)2 in MgO-GGBS system, resulting in lower leachabilities of PTEs and higher mechanical strengths. Stabilization/solidification experiments demonstrated that MSWI FA (70 wt%) could be recycled by MgO-GGBS binder (30 wt%) into blocks with desirable 28-day compressive strengths (3.9 MPa) and PTEs immobilization efficiencies (99.8% for Zn and 99.7% for Pb). This work provides mechanistic insights on the immobilization mechanisms of PTEs in CaO/MgO-GGBS systems and suggests a promising MgO-GGBS binder for low-carbon treatment of MSWI FA.
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Affiliation(s)
- Chen Sun
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Weizhe Ge
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Yuying Zhang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Lei Wang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.
| | - Yan Xia
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China; School of Civil Engineering, Harbin Institute of Technology, Harbin, 150090, China
| | - Xiaoqing Lin
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Qunxing Huang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Shengyong Lu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
| | - Daniel C W Tsang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China
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Liu J, Wu D, Tan X, Yu P, Xu L. Review of the Interactions between Conventional Cementitious Materials and Heavy Metal Ions in Stabilization/Solidification Processing. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093444. [PMID: 37176327 PMCID: PMC10179848 DOI: 10.3390/ma16093444] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023]
Abstract
In the past few decades, solidification/stabilization (S/S) technology has been put forward for the purpose of improving soil strength and inhibiting contaminant migration in the remediation of heavy metal-contaminated sites. Cement, lime, and fly ash are among the most common and effective binders to treat contaminated soils. During S/S processing, the main interactions that are responsible for improving the soil's behaviors can be summarized as gelification, self-hardening, and aggregation. Currently, precipitation, incorporation, and substitution have been commonly accepted as the predominant immobilization mechanisms for heavy metal ions and have been directly verified by some micro-testing techniques. While replacement of Ca2+/Si4+ in the cementitious products and physical encapsulation remain controversial, which is proposed dependent on the indirect results. Lead and zinc can retard both the initial and final setting times of cement hydration, while chromium can accelerate the initial cement hydration. Though cadmium can shorten the initial setting time, further cement hydration will be inhibited. While for mercury, the interference impact is closely associated with its adapted anion. It should be pointed out that obtaining a better understanding of the remediation mechanism involved in S/S processing will contribute to facilitating technical improvement, further extension, and application.
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Affiliation(s)
- Jingjing Liu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Dongbiao Wu
- Anhui Urban Construction Design Institute Corp., Ltd., Hefei 230051, China
| | - Xiaohui Tan
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Peng Yu
- Anhui Urban Construction Design Institute Corp., Ltd., Hefei 230051, China
| | - Long Xu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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