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Zhu G, Wang X, Yin X, Zhu M, Li J, Cao L, Sun Z, Zeng H. Influence of inherent minerals on metalworking fluids sludge pyrolysis: Products characterization and heavy metals behavior. Heliyon 2024; 10:e26256. [PMID: 38380051 PMCID: PMC10877409 DOI: 10.1016/j.heliyon.2024.e26256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 01/26/2024] [Accepted: 02/08/2024] [Indexed: 02/22/2024] Open
Abstract
Safely and appropriately disposing of metalworking fluids sludge (MFS) remains a challenge owing to its highly hazardous properties, this work investigated MFS pyrolysis at various temperatures (500, 600, 700, 800, and 900 °C) for energy recovery and safety treatment of MFS. The experimental results indicated that inherent minerals at higher temperatures could enhance the gas yields and promote the qualities of oil and gas from MFS pyrolysis. The highest pyrolysis gas yield was achieved at 18.86 wt% after MFS pyrolysis at 900 °C. GC-MS analysis revealed that the inherent minerals facilitated a decrease in oxygenated and nitrogenated compounds within the oil, while simultaneously leading to a substantial increase in hydrocarbon contents. Notably, the highest content of aromatics (61.16%) was attained during pyrolysis at 900 °C. Moreover, inherent minerals improved carbon sequestration and the characteristics of biochar during the MFS pyrolysis. The leaching contents of heavy metals in biochars were reduced, thereby reducing the heavy metals associated environmental risk. This research suggests that the pyrolysis process was a promising approach for simultaneous energy recovery and MFS disposal with low environmental risk.
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Affiliation(s)
- Guidan Zhu
- School of Chemistry and Chemical Engineering, Changji University, Changji, 831100, China
| | - Xingdong Wang
- Department of Civil Engineering, 23 College Walk, Monash University, Victoria, 3800, Australia
| | - Xuan Yin
- College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Mengmeng Zhu
- Xinjiang Qinghua Energy Group Co., Ltd., Yining, 835100, China
| | - Jiaying Li
- School of Chemistry and Chemical Engineering, Changji University, Changji, 831100, China
| | - Ling Cao
- School of Chemistry and Chemical Engineering, Changji University, Changji, 831100, China
| | - Zhiyang Sun
- School of Chemistry and Chemical Engineering, Changji University, Changji, 831100, China
| | - Hehua Zeng
- School of Chemistry and Chemical Engineering, Changji University, Changji, 831100, China
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2
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Zhang W, Song Q, Wang X, Wang X, Li H, Yang Z. Experimental study and modeling analysis of sewage sludge smoldering combustion at different airflow rates. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 168:126-136. [PMID: 37290341 DOI: 10.1016/j.wasman.2023.06.001] [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: 03/07/2023] [Revised: 05/29/2023] [Accepted: 06/02/2023] [Indexed: 06/10/2023]
Abstract
Sewage sludge is a major by-product of wastewater treatment, and its unfavorable properties are frequently a key restriction of disposal technologies, resulting in high costs and ineffective waste management. Smoldering combustion is a new technique for disposing of organic solid waste with high moisture content, which efficiently recovers energy with minimal igniting energy requirements. The objective of this study is to investigate the effects of airflow rate on sewage sludge (SS) smoldering combustion by combining experimental and modeling analyses. Results show that air channeling easily forms at the reactor's edge, intensifying the smoldering reaction and forming a concave smoldering front. The minimum airflow rate required for self-sustaining smoldering is 0.3 cm/s. As the airflow rate increases, convective heat transfer becomes dominant over conduction and radiation, resulting in a surge in smoldering temperature and velocity at 0.6 cm/s, followed by a linear increase. The maximum airflow rate at which the smoldering process can propagate stably during SS disposal is 8 cm/s. The expressions of the smoldering characteristics are obtained by using the activation energy asymptotic approach, and the calculated and experimental values show the same trend of variation, with good agreement at low airflow rate conditions. Sensitivity analysis shows that porosity φ is the most crucial parameter affecting smoldering temperature and velocity.
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Affiliation(s)
- Wei Zhang
- School of Energy Science and Engineering, University of Science and Technology of China, Jinzhai Road, Hefei 230026, China; Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Road, Guangzhou 510640, China
| | - Qianshi Song
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Road, Guangzhou 510640, China.
| | - Xiaohan Wang
- School of Energy Science and Engineering, University of Science and Technology of China, Jinzhai Road, Hefei 230026, China; Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Road, Guangzhou 510640, China.
| | - Xiaowei Wang
- School of Mechanical and Power Engineering, Guangdong Ocean University, Haida Road, Zhanjiang 524088, China
| | - Haowen Li
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Road, Guangzhou 510640, China
| | - Zixin Yang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Road, Guangzhou 510640, China
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Yuan Z, Ma W, Zhu N, Zhu Y, Wu S, Lou Z. Identifying the fate of nitrogenous species during sewage sludge pyrolysis via in-situ tracing of protein-sludge inherent components interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160437. [PMID: 36427709 DOI: 10.1016/j.scitotenv.2022.160437] [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: 09/17/2022] [Revised: 11/10/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
The effect of interactions between different components in sewage sludge on the thermochemical transformation of nitrogenous species is usually neglected, which is important to explain the generation mechanism of some key nitrogenous by-products. Here, we investigated the distribution, form, and chemical properties of the products from sludge-extracted protein (PR) under different pyrolysis scenarios using several in-situ probe techniques, to elucidate the critical role of typical sludge organics/inorganics on the evolution of nitrogenous intermediates and by-products. The results suggested that Ca/Fe/Si/Al-containing inorganics significantly affected the pyrolytic behavior of PR and the thermal transformation of nitrogenous species, while sludge organics, including humic acids and polysaccharides, had limited effects on the temperature-dependent evolution of nitrogenous species in PR. Among them, calcium oxide catalyzed the ring-opening reaction of heterocyclic-N with aromatic-like structures, resulting in a 21.1 %-68.8 % reduction in nitrogen fixation efficiency in the char. At lower temperatures (350-450 °C), calcium oxide caused more nitrogen to be transferred to the gas/tar phases in the form of NH3 and heterocyclic-N, and it also enhanced the conversion of nitrile-N → HCN → NO at temperatures above 450 °C. In contrast, polyferric salts inhibited the devolatilization of mono-heterocyclic-N and enhanced the thermal stability of poly-heterocyclic-N, resulting in a maximum increase of 18.5 mg·g-1 of nitrogen content in the char, while reducing the release of NH3 and HCN by 71.1 % and 32.0 %. This work elucidated the interaction between PR and inherent components in sludge, providing key information for the control of nitrogenous volatiles and NOx.
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Affiliation(s)
- Zhihang Yuan
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Wenchao Ma
- School of Environmental Science and Engineering, Tianjin Key Lab of Biomass/Wastes Utilization, Tianjin University, Tianjin 300072, China
| | - Nanwen Zhu
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Ying Zhu
- Advanced Materials Institute, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250014, China
| | - Shaolin Wu
- Shanghai Solid Waste Management Center, Shanghai 200235, China
| | - Ziyang Lou
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; China Institute for Urban Governance, Shanghai Jiao Tong University, Shanghai 200240, China.
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4
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Valorization of Fourth-Range Wastes: Evaluating Pyrolytic Behavior of Fresh and Digested Wastes. FERMENTATION 2022. [DOI: 10.3390/fermentation8120744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Changes in daily habits and a stressful lifestyle create modifications in consumer preferences and open opportunities to new market products. This is the case of fourth-range products in which the industrial sector generates a waste stream of high quality. Valorization of this type of waste as a single stream is desirable to avoid lowering quality with other low-grade materials. Anaerobic digestion of fourth-range wastes was studied under discontinuous and semi-continuous conditions. A high carbon content characterizes the organic material composed of fruit and vegetable wastes. The fast degradation of the substrate indicated no limitations associated with the hydrolysis stage, as observed from kinetic parameters estimated from batch assays. However, the easiness of degradation did not translate into short hydraulic retention times when operating under semi-continuous conditions. Additionally, the insufficient amount of nutrients prevented the development of a well-balanced digestion process. Specific methane production was 325 mL CH4/g VS added at a hydraulic retention time of 30 days. However, solid accumulation was observed at the end of the experiment, indicating that conditions established did not allow for the complete conversion of the organic material. Digestate evaluation using thermal analysis under inert conditions showed a thermal profile evidencing the presence of complex components and a high tendency to char formation.
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Cao C, Cheng Y, Hu H, Wang H, Liu S, Hu M, Li X, Yao H. Products distribution and sulfur fixation during the pyrolysis of CaO conditioned textile dyeing sludge: Effects of pyrolysis temperature and heating rate. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 153:367-375. [PMID: 36191497 DOI: 10.1016/j.wasman.2022.09.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 09/02/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Textile dyeing sludge (TDS) is a typical industrial solid waste whose amount surged with the textile industry's development. Pyrolysis treatment is a promising technique for TDS to realize harmless disposal and resource reuse. However, the high content of organic compounds would cause sulfurous pollutants emission, reducing the economic feasibility during pyrolysis. This study aimed to fill the knowledge gaps about the thermal behavior, products distribution, kinetics, and sulfur transformation during TDS pyrolysis in 350-575 ℃ with the heating rate of 60, 600, and 6000 ℃/min, then investigate the sulfur fixation effect of CaO under representative conditions (350 ℃, 650 ℃ with 60 ℃/min, 6000 ℃/min). The primary decomposition stage of TDS is observed in 127-557 ℃, following the Avrami-Erofeev (n = 3) model, while the activation energy presents a convergent tendency with the increased heating rate. The pyrolysis temperature and heating rates impact the cracking of organic compounds, while a weakening effect is found for the sulfur distribution. CaO addition could efficiently realize sulfur fixation in char by absorbing sulfurous gas products, but SO2 escape appeared with the increased CaO fraction. Pyrolysis condition at 650 ℃-60 ℃/min with 10 wt% CaO addition is recommended to achieve high sulfur retention, and the sulfur transformation mechanism in char during the TDS pyrolysis with and without CaO is proposed. Our findings provide novel and fundamental insights into the efficient disposal and pollution control during TDS pyrolysis.
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Affiliation(s)
- Chengyang Cao
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yetao Cheng
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hongyun Hu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Hao Wang
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shuai Liu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ming Hu
- Everbright Envirotech (Nanjing) Ltd, Nanjing 211106, China
| | - Xian Li
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hong Yao
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
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Chen C, Ling H, Qiu S, Huang X, Fan D, Zhao J. Microwave catalytic co-pyrolysis of chlorella vulgaris and oily sludge: Characteristics and bio-oil analysis. BIORESOURCE TECHNOLOGY 2022; 360:127550. [PMID: 35779745 DOI: 10.1016/j.biortech.2022.127550] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Co-pyrolysis of Chlorella vulgaris (CV) and Oily sludge (OS) under different mixing ratios were investigated by microwave furnace. NiO, activated carbon (AC) and their 1:1 compound (N1A1) with different additions (5%, 10%, 15% and 20%) were selected as microwave additives to study the effects on optimum mixing ratio of co-pyrolysis. The results indicated that mixing ratio of CV/OS = 1:1 (C1O1) was optimum for co-pyrolysis. Besides, 10% AC was optimal on improving pyrolysis characteristics of the C1O1 group. The most significant synergistic interaction of NiO and AC occurred in the 10% N1A1 group. Moreover, hydrocarbons in bio-oil of the C1O1 group increased by 31.84% compared with theoretical values, while nitrogenous, oxygenated compounds decreased by 74.18% and 19.01%. Addition of 10% N1A1 in the C1O1 group increased aliphatic hydrocarbons by 22.44%, and decreased nitrogenous, oxygenated compounds by 41.79% and 36.58%. Overall, 10% N1A1 was conducive for the C1O1 group to obtain high-quality bio-oil.
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Affiliation(s)
- Chunxiang Chen
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China; Guangxi Key Laboratory of Petrochemical Resources Processing and Process Intensification Technology, Nanning City 530004, PR China; Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization, Guangzhou City 510640, PR China.
| | - Hongjian Ling
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China
| | - Song Qiu
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China
| | - Xiaodong Huang
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China
| | - Dianzhao Fan
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China
| | - Jian Zhao
- College of Mechanical Engineering, Guangxi University, University Road 100, Xixiangtang District, Nanning City 530004, PR China
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Zhou X, Chen X, Han W, Han Y, Guo M, Peng Z, Fan Z, Shi Y, Wan S. Tetracycline Removal by Hercynite-Biochar from the Co-Pyrolysis of Red Mud-Steel Slag-Sludge. NANOMATERIALS 2022; 12:nano12152595. [PMID: 35957024 PMCID: PMC9370334 DOI: 10.3390/nano12152595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/21/2022] [Accepted: 07/23/2022] [Indexed: 12/10/2022]
Abstract
The sludge-derived biochar is considered an effective emerging contaminants adsorbent for wastewater treatment. In this paper, red mud and steel slag (RMSS) was used for improving sludge dewaterability and enhancing the sludge-derived biochar adsorption capacity. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscope (SEM) were employed to comprehensively characterize the mineral composition, functional group, and morphology of the adsorbent. RMSS was able to improve the sludge dewatering performance by providing a skeleton structure to promote drainage and Fe(III) to decrease the Zeta potential. The dosage of 20 mg/g RMSS was able to reduce the specific resistance to filtration (SRF) and the Zeta potential of sludge from 1.57 × 1013 m/kg and −19.56 mV to 0.79 × 1013 m/kg and −9.10 mV, respectively. The co-pyrolysis of RMSS and sludge (2:8) induced the formation of biochar containing FeAl2O4 (PS80). The PS80 exhibited a large surface area (46.40 m2/g) and high tetracycline (TC) removal capacity (98.87 mg/g) when combined with H2O2 (PS80-H2O2). The adsorption process of TC onto PS80 and PS80-H2O2 was well described by the pseudo-first-order and pseudo-second-order kinetic model, indicating physisorption and chemisorption behavior. The results indicated that co-pyrolysis of RMSS sludge PS80-H2O2 could enhance the biochar adsorption capacity of TC, attributable to the degradation by ·OH generated by the heterogeneous Fenton reaction of FeAl2O4 and H2O2, the release of adsorbed sites, and the improvement of the biochar pore structure. This study proposed a novel method for the use of RMSS to dewater sludge as well as to induce the formation of FeAl2O4 in biochar with effective TC removal by providing a Fe and Al source, achieving a waste-to-resource strategy for the integrated management of industrial solid waste and sewage sludge.
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Affiliation(s)
- Xian Zhou
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Xia Chen
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Wei Han
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Yi Han
- College of Resources and Environment, Anqing Normal University, Anqing 246011, China;
- Correspondence:
| | - Mengxin Guo
- College of Resources and Environment, Anqing Normal University, Anqing 246011, China;
| | - Ziling Peng
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Zeyu Fan
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Yan Shi
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
| | - Sha Wan
- Changjiang River Scientific Research Institute, Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China; (X.Z.); (X.C.); (W.H.); (Z.P.); (Z.F.); (Y.S.); (S.W.)
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8
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Zuhara S, Mackey HR, Al-Ansari T, McKay G. A review of prospects and current scenarios of biomass co-pyrolysis for water treatment. BIOMASS CONVERSION AND BIOREFINERY 2022:1-30. [PMID: 35855911 PMCID: PMC9277991 DOI: 10.1007/s13399-022-03011-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
With ever-growing population comes an increase in waste and wastewater generated. There is ongoing research to not only reduce the waste but also to increase its value commercially. One method is pyrolysis, a process that converts wastes, at temperatures usually above 300 °C in a pyrolysis unit, to carbon-rich biochars among with other useful products. These chars are known to be beneficial as they can be used for water treatment applications; certain studies also reveal improvements in the biochar quality especially on the surface area and pore volume by imparting thermal and chemical activation methods, which eventually improves the uptake of pollutants during the removal of inorganic and organic contaminants in water. Research based on single waste valorisation into biochar applications for water treatment has been extended and applied to the pyrolysis of two or more feedstocks, termed co-pyrolysis, and its implementation for water treatment. The co-pyrolysis research mainly covers activation, applications, predictive calculations, and modelling studies, including isotherm, kinetic, and thermodynamic adsorption analyses. This paper focuses on the copyrolysis biochar production studies for activated adsorbents, adsorption mechanisms, pollutant removal capacities, regeneration, and real water treatment studies to understand the implementation of these co-pyrolyzed chars in water treatment applications. Finally, some prospects to identify the future progress and opportunities in this area of research are also described. This review provides a way to manage solid waste in a sustainable manner, while developing materials that can be utilized for water treatment, providing a double target approach to pollution management.
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Affiliation(s)
- Shifa Zuhara
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Hamish R. Mackey
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Tareq Al-Ansari
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
- Division of Engineering Management and Decision Sciences, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Gordon McKay
- Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
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9
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Bentley MJ, Kearns JP, Murphy BM, Summers RS. Pre-pyrolysis metal and base addition catalyzes pore development and improves organic micropollutant adsorption to pine biochar. CHEMOSPHERE 2022; 286:131949. [PMID: 34426297 DOI: 10.1016/j.chemosphere.2021.131949] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Biochars were produced from pine feedstock pretreated with aqueous base, NaOH, at pH 9 and 11, and alkali and alkaline earth metals (AAEMs) Na, K, Ca, and Mg at 10-3 and 1 M. The effects of base and AAEM feedstock pretreatment on biochar surface area, pore size distribution, and adsorption capacity of two organic micropollutants (OMPs), 2,4-dichlorophenoxyacetic acid and sulfamethoxazole, from surface water with background dissolved organic matter (DOM) were evaluated. Base pretreatment significantly increased surface area within micropores (<2 nm diameter). AAEM pretreatment caused pore widening, increasing surface area within pores >2 nm in diameter. The catalytic activity of AAEMs, assessed by generation of non-micropore surface area, decreased in the following order: Ca > K > Na > Mg. All pretreated biochars outperformed untreated biochar for OMP adsorption. Biochar pretreated by aqueous base at pH 11 showed over an order of magnitude increase in OMP adsorption, nearly matching the performance of commercial activated carbon. OMP adsorption from surface water was positively correlated with biochar micropore surface area and negatively correlated with non-micropore surface area, which was linked to higher levels of DOM competition. Base and AAEM pretreatment of biochar feedstocks can increase OMP adsorption for water treatment applications by tuning pore structure and surface area.
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Affiliation(s)
- Matthew J Bentley
- University of Colorado Boulder, Environmental Engineering, 4001 Discovery Drive - 607 UCB, Boulder, CO, 80309, USA.
| | - Joshua P Kearns
- Aqueous Solutions, 1935 Pike Rd, Moravian Falls, NC, 28654, USA.
| | - Benjamin M Murphy
- Carollo Engineers, 390 Interlocken Crescent, Suite 800, Broomfield, CO, 80021, USA.
| | - R Scott Summers
- University of Colorado Boulder, Environmental Engineering, 4001 Discovery Drive - 607 UCB, Boulder, CO, 80309, USA
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10
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Wang B, Xu X, Cao X, Liu Y. Pyrolysis of predried dyeing sludge: Weight loss characteristics, surface morphology, functional groups and kinetic analysis. CAN J CHEM ENG 2021. [DOI: 10.1002/cjce.24048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bo Wang
- State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China
| | - Xiang Xu
- Guangzhou Shincci Energy Equipment Co. Ltd Guangzhou China
| | - Xiu Cao
- State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China
| | - Yinhe Liu
- State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China
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11
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Zhang H, Wang Z, Du C, Liu W, Gerson AR, Pi K. Properties and heavy metal leaching characteristics of leachate sludge-derived biochar. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:3064-3074. [PMID: 34731909 DOI: 10.1002/wer.1658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 10/07/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Heavy metals and metalloids, in sludge and sediments, are environmental pollutants of concern with long-term negative effects on human and ecological health. In this study, sludge from biological treatment of municipal waste leachate was pyrolyzed into leachate sludge-derived biochar (LSDB) at 300°C to 900°C, comprising complex organic and inorganic (particularly heavy metals) species formed from heterogeneous chemical reactions. Based on different advanced material analyses, that is, Thermogravimetric Analysis (TGA), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis, this study revealed that mass loss and microstructural changes of LSDBs occurred primarily due to decomposition of volatiles, aromatic rings, carbonates, and hydroxides. The leaching behaviors of heavy metals from LSDBs were evaluated using the Synthetic Precipitation Leaching Procedure (SPLP). The final pH in SPLP increased from 7.5 to 12.5 with pyrolysis temperature. The pH increase favored the retention of heavy metals in the LSDBs due to the formation of low soluble precipitates at alkaline pH. The heavy metals and metalloids in the LSDBs were present as surface precipitates due to precipitation and cation exchange rather than surface complexation. The leaching contents of metals and metalloids, such as Cr, Cd, Ni, Pb, and As, were all below their respective maximum discharge standards for the first priority pollutants in China.
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Affiliation(s)
- Huiqin Zhang
- Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan, China
| | - Zixian Wang
- Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan, China
| | - Chenyu Du
- Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan, China
| | - Wenlong Liu
- Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan, China
| | - Andrea R Gerson
- Acid and Metalliferous Mine Drainage, Blue Minerals Consultancy, Wattle Grove, Tasmania, Australia
| | - Kewu Pi
- Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan, China
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Ghodke PK, Sharma AK, Pandey JK, Chen WH, Patel A, Ashokkumar V. Pyrolysis of sewage sludge for sustainable biofuels and value-added biochar production. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 298:113450. [PMID: 34388542 DOI: 10.1016/j.jenvman.2021.113450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
The study deals with the pyrolysis of sewage sludge to produce eco-friendly and sustainable fuels along with value-added biochar products. The experiments were conducted in a fixed-bed cylindrical glass reactor in the temperature range of 250-700 °C and achieved the product yield of 22.4 wt% bio-oil, 18.9 wt % pyrolysis gases, and 58.7 wt% biochar at 500 °C optimum temperature. The chemical composition of bio-oil was investigated by gas chromatograph-mass spectroscopy and fourier transformation infrared techniques. The ASTM standard procedures were used to assess the fuel qualities of bio-oil, and they were found to be satisfactory. Bio-oil has a greater H/C ratio (3.49) and a lower O/C ratio (1.10), indicating that it is suitable for engine use. The gas chromatographic analysis of pyrolysis gases confirmed the presence of 41.16 wt % combustible gases, making it suitable for use in spark-ignition engines. X-ray fluorescence analysis of biochar showed that it had a good amount of carbon, nitrogen, phosphorus, and potassium along with some micro-and macro-nutrient which proves its potential to utilize as organic manure in the agriculture sector. In addition, the data obtained from the TGA analysis during the pyrolysis of sewage sludge was applied to calculate kinetic parameters via the Coats-Redfern method.
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Affiliation(s)
- Praveen Kumar Ghodke
- Department of Chemical Engineering, National Institute of Technology Calicut, Kozhikode, 673601, Kerala, India
| | - Amit Kumar Sharma
- Department of Chemistry, Centre for Alternate and Renewable Energy Research, R&D, University of Petroleum & Energy Studies (UPES), School of Engineering, Energy Acres Building, Bidholi, Dehradun, 248007, Uttarakhand, India.
| | - J K Pandey
- Department of Chemistry, School of Basic and Applied Sciences, Adamas University, Kolkata, 700 126, India
| | - Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung, 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung, 411, Taiwan
| | - Alok Patel
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-971 87, Luleå, Sweden
| | - Veeramuthu Ashokkumar
- Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Department of Energy and Environmental Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, 600077, India
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13
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Preparation and Characterization of Activated Carbon Obtained from Water Treatment Plant Sludge for Removal of Cationic Dye from Wastewater. Processes (Basel) 2020. [DOI: 10.3390/pr8121549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The proposal of this work was the preparation and characterization of activated carbons obtained from water treatment plant sludge (WTS) to apply as adsorbents in the removal of organic dye contaminants from wastewater. The activated carbons were produced with a combination of chemical activation and pyrolysis processes. The textural characteristics of both adsorbents presented a satisfactory superficial area and mesoporous structure. The presence of phenolic and carboxylic groups in the surface indicated a better adsorption of cationic adsorbates. When applied as adsorbents in the removal of methylene blue (MB) from wastewater, the maximum removal values obtained were up to 96%. The adsorption results showed that the adsorption was faster in the beginning and reached maximum around 30 min. The Elovich kinetic model and the Sips isotherm model presented the best fit to experimental data, which was checked by analysis of variance (ANOVA). The production of activated carbons from WTS is a sustainable and effective option in the removal of MB dye.
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Luo J, Lin J, Ma R, Chen X, Sun S, Zhang P, Liu X. Effect of different ash/organics and C/H/O ratios on characteristics and reaction mechanisms of sludge microwave pyrolysis to generate bio-fuels. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 117:188-197. [PMID: 32861081 DOI: 10.1016/j.wasman.2020.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/17/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
To study the effects of different ash/organics and C/H/O ratios on bio-fuel characteristics and energy efficiency, four kinds of sludge with different properties were used for microwave pyrolysis (800 °C). Moreover, the microwave pyrolysis reaction mechanisms of different sludge were also explored. The results showed that high-ash sludge could accelerate the frequency of polar molecule rotation in the microwave field due to the presence of oxides with dielectric properties in ash, thereby achieving faster heating rates and higher temperatures. However, compared with high-organic sludge, high-ash sludge exhibited lower bio-gas yield and higher bio-char yield. As the H/C ratio increased from 0.127 to 0.148, the bio-gas yield increased from 15.41% to 40.01%, and the content of H2 in bio-gas and aliphatics in bio-oil increased to 36.69 vol% and 26.54 wt%, respectively. When the O/C ratio was reduced to 1.31, the content of CO and oxygenated compound in bio-oil increased to 31.25 vol% and 40.04 wt%, which lowered the quality of the bio-oil. Those consequences also determined that a mixture of sludge with different ash/organic ratios could be pyrolyzed to obtain high-quality bio-fuels and high energy efficiency. Differences in C/H/O ratios in the mixed sludge greatly affected the microwave pyrolysis heating process, which affected the pyrolysis reactions and the quality of the bio-fuels. Therefore, this study provides a theoretical basis to elevate the quality of bio-fuels and reduce microwave pyrolysis costs.
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Affiliation(s)
- Juan Luo
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Junhao Lin
- School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Rui Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xing Chen
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Shichang Sun
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China; Research Center for Water Science and Environmental Engineering, Shenzhen University, 518055, China.
| | - Peixin Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiangli Liu
- Shenzhen Engineering Laboratory of Aerospace Detection and Imaging, Department of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
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15
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Liu Y, Ran C, Siyal AA, Song Y, Jiang Z, Dai J, Chtaeva P, Fu J, Ao W, Deng Z, Zhang T. Comparative study for fluidized bed pyrolysis of textile dyeing sludge and municipal sewage sludge. JOURNAL OF HAZARDOUS MATERIALS 2020; 396:122619. [PMID: 32361128 DOI: 10.1016/j.jhazmat.2020.122619] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/28/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
A comparative research was performed to evaluate the products yields and chars properties for pyrolysis of textile dyeing sludge (TDS) and municipal sewage sludge (MSS). The high fixed carbon (19.36 wt%) and low volatile (23.66 wt%) contents of TDS resulted in higher char yields and lower condensate yields. TDS char (TC) had a higher sulfur (S) retention efficiency than MSS char (MC) and CaO exhibited a great S retention effect in MC. More alkali and alkaline earth metals (e.g. Na, K, Mg and Ca) in MSS contributed to enhanced catalytic pyrolysis. In comparison to non-catalytic pyrolysis, chars from catalytic pyrolysis had lower iodine number and higher methylene blue (MB) adsorption value. MB adsorption values of MC (212.28-414.20 mg/g) were much higher than those of TC (84.32-156.07 mg/g). In contrast, heavy metals risk degrees of MC (4.20-7.56) were lower than those of TC (7.55-12.87), and heavy metals in TC and MC showed slight risks to environment.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chunmei Ran
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Asif Ali Siyal
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yongmeng Song
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Zhihui Jiang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianjun Dai
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Polina Chtaeva
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jie Fu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wenya Ao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Zeyu Deng
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Tianhao Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China; College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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Gong W, Zhou Z, Liu Y, Wang Q, Guo L. Catalytic Gasification of Sewage Sludge in Supercritical Water: Influence of K 2CO 3 and H 2O 2 on Hydrogen Production and Phosphorus Yield. ACS OMEGA 2020; 5:3389-3396. [PMID: 32118153 PMCID: PMC7045557 DOI: 10.1021/acsomega.9b03608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
In this work, the catalytic gasification of sewage sludge in supercritical water was investigated in a batch reactor (460 °C, 27 MPa, 6 min), and the separate and combined effects of the catalyst on the H2 production and phosphorus yield were investigated. The experimental results indicated that K2CO3 alone improved the H2 yield, gasification efficiency (GE), and carbon gasification efficiency (CE). The largest H2 yield of 54.28 mol/kg was achieved, which was approximately three times that without a catalyst. Furthermore, the inorganic phosphorus (IP) yield increased with the addition of K2CO3. However, when H2O2 was added, the H2 yield quickly decreased with increasing H2O2 coefficient, and more than 97.8% of organic phosphorus (OP) was converted into IP. The H2 yield increased with the addition of various K2CO3/H2O2 ratios, whereas the IP yield decreased.
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Affiliation(s)
- Weijin Gong
- School of Energy & Environmental
Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Zizheng Zhou
- School of Energy & Environmental
Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Yue Liu
- School of Energy & Environmental
Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Qingyu Wang
- School of Energy & Environmental
Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Lina Guo
- School of Energy & Environmental
Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
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17
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Meng HS, Chen C, Yan ZR, Li XY, Xu J, Sheng GP. Co-doping polymethyl methacrylate and copper tailings to improve the performances of sludge-derived particle electrode. WATER RESEARCH 2019; 165:115016. [PMID: 31470283 DOI: 10.1016/j.watres.2019.115016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 08/09/2019] [Accepted: 08/19/2019] [Indexed: 06/10/2023]
Abstract
Three-dimensional electrochemical reactor (3DER) is a highly efficient technology for refractory wastewater treatment. Particle electrodes filled between anode and cathode are the core units of 3DER, determining the treatment efficiency of wastewater. However, particle electrodes deactivation due to catalytic sites coverage seriously impedes the continuous operation of 3DER. In this work, granular sludge carbon (GSC) particle electrodes being resistant to deactivation are fabricated by pyrolyzing the mixture of waste sludge, polymethyl methacrylate (PMMA), and copper tailings, whose performances are evaluated by degrading rhodamine B (RhB) wastewater in a continuous-flow 3DER. Results indicate that hierarchical-pore structure comprising macro-, meso-, and micropores is developed in GSC-10-CTs by doping 10 g PMMA and 5 g copper tailings into 100 g waste sludge. PMMA contributes to construct macropores, which is essential for the mass transfer of RhB into GSC particle electrodes of centimeter-size. Copper tailings promote the formation of meso- and micro-pores in GSCs, as well as improving the electrochemical properties. Consequently, GSC-10-CTs packed 3DER exhibits the highest removal efficiency and lowest energy consumption for RhB treatment. In addition, the compressive strength of GSC-10-CTs is enhanced by copper tails, that is crucial to fill into 3DER as particle electrodes. The high-efficient and cost-effective GSC-10-CTs fabricated by waste materials have the potential of substituting commercial granular activated carbon catalysts in the future, consequently promoting the application of 3DER in wastewater treatment.
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Affiliation(s)
- Hui-Shan Meng
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Chen Chen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Zi-Run Yan
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Xiu-Yan Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Juan Xu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China; Institute of Eco-Chongming (IEC), No.20 Cuiniao Road, ChenJiazhen, Shanghai, 202162, China.
| | - Guo-Ping Sheng
- CAS Key Laboratory of Urban Pollutant Conversion, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, China
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18
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Li X, Lin S, Hao T, Khanal SK, Chen G. Elucidating pyrolysis behaviour of activated sludge in granular and flocculent form: Reaction kinetics and mechanism. WATER RESEARCH 2019; 162:409-419. [PMID: 31299428 DOI: 10.1016/j.watres.2019.06.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/06/2019] [Accepted: 06/30/2019] [Indexed: 06/10/2023]
Abstract
The pyrolysis kinetics of sewage sludge was studied to determine the constituent of sludge and explore the feasibility of pyrolytic post-treatment. Both flocculent sludge and granular sludge were pyrolysed in a thermogravimetric analyser under inert atmospheric conditions. The pyrolysis of granular sludge and flocculent sludge were described by three parallel reactions model with three individual pseudo-components. The decomposition activation energy values of the three pseudo-components were determined by iso-conversional methods to be 263.97 kJ/mol, 257.18 kJ/mol and 153.61 kJ/mol in flocculent sludge and 139.89 kJ/mol, 228.78 kJ/mol and 142.78 kJ/mol in granular sludge, respectively. Granular sludge exhibited better thermal stability but lower devolatilisation activation energy than flocculent sludge, which could be attributed by enriched alkali and alkaline metals during granulation. Master plots of experimental data sets suggested that the decomposition of all organic pseudo-components of flocculent sludge followed the nth-order mechanism while the pyrolytic mechanism of the first organic fraction in granular sludge coincided with random nucleation and nuclei growth. By investigating the pyrolytic behaviour, this study sheds light on the composition of granular sludge and the impact of sludge components on granular sludge pyrolysis, and lays the foundation for the treatment of waste granular sludge with potential for resource and energy recovery in the near future.
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Affiliation(s)
- Xiling Li
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Sen Lin
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Tianwei Hao
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, China; Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
| | - Samir Kumar Khanal
- Department of Molecular Biosciences and Bioengineering, University of Hawai᾽i at Mānoa, 1995 East-West Road, Honolulu, HI, 96822, USA
| | - Guanghao Chen
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Treatment Laboratory, FYT Graduate School, The Hong Kong University of Science and Technology, Nansha, Guangzhou, China
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Weijin G, Zizheng Z, Yue L, Qingyu W, Lina G. Hydrogen production and phosphorus recovery via supercritical water gasification of sewage sludge in a batch reactor. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 96:198-205. [PMID: 31376965 DOI: 10.1016/j.wasman.2019.07.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 07/08/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
In this study, gasification of sewage sludge in supercritical water using a batch reactor was investigated. The effects of temperature, retention time, and the oxidation coefficient on gas composition, gas yield, total organic carbon removal efficiency (XTOC), gasification efficiency (GE), carbon gasification efficiency (CE), and phosphorus release rate (Xp) were investigated. The experimental results indicated that the yields for hydrogen, methane, and carbon dioxide increased with the increase in temperature from 380 °C to 460 °C. A maximum hydrogen molar fraction of 55.72% and a yield of 19.86 mol/kg were obtained at 460 °C and 27 MPa after 6 min. The GE, CE, XTOC, and Xp also increased with the increase in temperature. An extension of the retention time promoted the gasification of sludge, thereby resulting in an increase in the hydrogen and methane molar fraction, yield, GE, CE, XTOC, and Xp. Under the conditions of 420 °C and 27 MPa after 6 min, with an increase in the oxidation coefficient from 1.5 to 2.5, the oxidation reaction became dominant in the supercritical water. Hydrogen and methane were converted to carbon dioxide and water with an excess of hydrogen peroxide, which resulted in a lower hydrogen yield. However, the decomposition of organic compounds in the sludge was promoted with the addition of hydrogen peroxide, thereby resulting in an increase in the GE, CE, XTOC, and Xp. When the oxidation coefficient reached 2.5, a maximum GE of 131.6% and Xp of 98.74% were obtained.
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Affiliation(s)
- Gong Weijin
- School of Energy & Environmental Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China.
| | - Zhou Zizheng
- School of Energy & Environmental Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Liu Yue
- School of Energy & Environmental Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Wang Qingyu
- School of Energy & Environmental Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Guo Lina
- School of Energy & Environmental Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
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Abstract
We propose a ‘Waste to Carbon’ thermal transformation of sewage sludge (SS) via torrefaction to a valuable product (fuel) with a high content of carbon. One important, technological aspect to develop this concept is the determination of activation energy needed for torrefaction. Thus, this research aimed to evaluate the kinetics of SS torrefaction and determine the effects of process temperature on fuel properties of torrefied products (biochars). Torrefaction was performed using high ash content SS at six (200~300 °C) temperatures and 60 min residence (process) time. Mass loss during torrefaction ranged from 10~20%. The resulting activation energy for SS torrefaction was ~12.007 kJ·mol−1. Initial (unprocessed) SS higher heating value (HHV) was 13.5 MJ·kg−1. However, the increase of torrefaction temperature decreased HHV from 13.4 to 3.8 MJ·kg−1. Elemental analysis showed a significant decrease of the H/C ratio that occurred during torrefaction, while the O/C ratio fluctuated with much smaller differences. Although the activation energy was significantly lower compared with lignocellulosic materials, low-temperature SS torrefaction technology could be explored for further SS stabilization and utilization (e.g., dewatering and hygienization).
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