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Feng Y, Darma AI, Yang J, Wang X, Shakouri M. Protaetia brevitarsis larvae produce frass that can be used as an additive to immobilize Cd and improve fertility in alkaline soils. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134379. [PMID: 38733779 DOI: 10.1016/j.jhazmat.2024.134379] [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: 10/12/2023] [Revised: 04/17/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024]
Abstract
Bioconversion of agricultural waste by Protaetia brevitarsis larvae (PBL) holds significant promise for producing high-quality frass organic amendments. However, the effects and mechanisms of PBL frass on Cd immobilization in an alkaline environment remain poorly understood. In this study, three types of frass, namely maize straw frass (MF), rice straw frass (RF), and sawdust frass (SF), were produced by feeding PBL. The Cd immobilization efficiencies of three frass in alkaline solutions and soils were investigated through batch sorption and incubation experiments, and spectroscopic techniques were employed to elucidate the sorption mechanisms of Cd onto different frass at the molecular level. The results showed that MF proved to be an efficient sorbent for Cd in alkaline solutions (176.67-227.27 mg g-1). X-ray absorption near-edge structure (XANES) spectroscopy indicated that Cd immobilization in frass is primarily attributed to the association with organic matter (OM-Cd, 78-90%). And MF had more oxygen-containing functional groups than the other frass. In weakly alkaline soils, MF application (0.5-1.5%) significantly decreased Cd bioavailability (5.65-18.48%) and concurrently improved soil nutrients (2.21-56.79%). Redundancy analysis (RDA) unveiled that pH, CEC, and available P were important factors controlling Cd fractions. Path analysis demonstrated that MF application affected Cd bioavailability directly and indirectly by influencing soil chemical properties and nutrients. In summary, MF, the product of PBL-mediated conversion maize straw, demonstrated promise as an effective organic amendment for Cd immobilization and fertility improvement in alkaline soils.
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Affiliation(s)
- Ya Feng
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China; College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Aminu Inuwa Darma
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, China)
| | - Jianjun Yang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China (Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, China).
| | - Xudong Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Mohsen Shakouri
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon S7N 2V3, Canada
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Li X, Zhang M, Li S, Wei W. Humic acid-mediated transport of a typical soil passivation remediation product (chloropyromorphite) in saturated porous media. J Environ Sci (China) 2024; 141:51-62. [PMID: 38408834 DOI: 10.1016/j.jes.2023.06.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 02/28/2024]
Abstract
Conversion of labile Pb species into chloropyromorphite (CPY) using phosphorus-bearing amendments was considered to be an ideal strategy in soil passivation remediation. However, the fate and transport of CPY in the soil are poorly understood. This study aims to fill the knowledge gap by evaluating the fate and transport of CPY under environmentally relevant conditions of humic acid (HA), pH, electrolyte concentration, and species through the saturated sandy medium. Results showed that bare CPY colloids are basically immobile in sandy porous media while the co-existence of HA made the transport of CPY improved by 30%-93.5%. Facilitated transport of CPY was attributed to the increased stability of CPY and the repulsive interaction between CPY particles and sands due to HA adsorption. The mobility of CPY was also increased with increasing pH from 5.0 to 9.0. When the pH was 9 with a 10 mmol/L NaCl background solution, the stronger energy barrier between CPY and sand led to enhanced transport behavior. The divalent Ca2+ had a more dramatic effect than monovalent Na+ on the aggregation and sedimentation of CPY colloids due to its effectivescreening of the surface charge of CPY and bridging interaction with CPY particles. Derjaguin-Landau-Verwey-Overbeek theory and attachment efficiency calculation indicated that high energy barriers were responsible for the high mobility of CPY colloids, while the retention of CPY in sands was mainly caused by secondary energy minimum and physically straining. The findings of this work can help to evaluate the fate of soil passivation remediation products in natural water and soil.
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Affiliation(s)
- Xinying Li
- School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China
| | - Mengjia Zhang
- School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China
| | - Siyuan Li
- School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China
| | - Wei Wei
- School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China.
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3
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Barreto MSC, Gomes FP, de Carvalho HWP, Alleoni LRF. Desorption kinetic and sequential extraction of Pb and Zn in a contaminated soil amended with phosphate, lime, biochar, and biosolids. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:120793-120804. [PMID: 37940822 DOI: 10.1007/s11356-023-30643-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/19/2023] [Indexed: 11/10/2023]
Abstract
The mining and metallurgical industry sector activities often release potential toxic elements (PTE) surrounding exploitation area. We evaluated the addition of phosphate and lime using the dosage of 0.5:1, 1:1, and 2:1 molar ratio of PO43- and CO32- to the sum of PTE, respectively, and also, biochar and biosolids using the dosage of 2.5, 5, and 10% (m:m) to immobilize PTE in contaminated forest soil (Pb (270 mg kg-1) and Zn (858 mg kg-1)) near an abandoned mine site in Brazil. The desorption by stirred flow kinetics revealed that 15% of the total Zn and 12% Pb contents are mobile before any amendment application. Phosphate amendment decreased Pb desorption but increased Zn desorption. Biochar and biosolids immobilize high amounts of Zn and Pb because of their high cation exchange capacities and alkaline properties; however, 20% biosolid dose increased Pb desorption. X-ray absorption spectroscopy suggested Zn-kerolite as the major species in the contaminated soil, likely from mine dust. The change in Zn speciation after soil amendment addition indicated that biochar and lime kept a high proportion of Zn-Al species, whereas phosphate and biosolids led to more Zn-Fe species. Our results pointed out that lime might reduce both Pb and Zn mobilities; however, field trials are crucial to confirm the immobilization efficiency of lime and other amendments over long term.
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Affiliation(s)
- Matheus Sampaio Carneiro Barreto
- Department of Plant & Soil Sciences, University of Delaware, 476 Harker ISE Lab, Newark, DE, 19716, USA.
- Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias, 11, São Paulo, Piracicaba, 13418-900, Brazil.
| | - Frederico Prestes Gomes
- Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias, 11, São Paulo, Piracicaba, 13418-900, Brazil
| | - Hudson Wallace Pereira de Carvalho
- College for Sustainable Agriculture and Environmental Science, Mohammed VI Polytechnic University, BenGuerir, 43150, Morocco
- Centre for Nuclear Energy in Agriculture, University of São Paulo, Avenida Centenário, São Paulo, Piracicaba, 303, 13416-000, Brazil
| | - Luís Reynaldo Ferracciú Alleoni
- Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias, 11, São Paulo, Piracicaba, 13418-900, Brazil
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Lu H, Yang Y, Huang K, Huang G, Hu S, Pan D, Liu T, Li X. Transformation kinetics of exogenous lead in an acidic soil during anoxic-oxic alteration: Important roles of phosphorus and organic matter. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122271. [PMID: 37506801 DOI: 10.1016/j.envpol.2023.122271] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/26/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023]
Abstract
Lead (Pb) can enter soil environment during flooding events such as surface runoff and intensive rainfall. However, the key transformation processes of exogenous Pb during anoxic-oxic alteration remain poorly understood particularly how phosphorus and organic matter contribute to Pb immobilization/release. Here, a kinetic model was established to investigate the Pb transformation in an acidic soil with two levels of Pb contamination under alternating anoxic-oxic conditions, based on the results of seven-step sequential extraction, dissolved organic carbon, sulfate, iron, phosphorus, and surface sites. Results showed that the potentially available Pb, including dissolved, exchangeable, and specifically adsorbed fractions, was gradually transferred to the fulvic complex, Fe-Mn oxides bound, and sulfides bound Pb after 40-day incubation under anoxic conditions, while the fulvic complex Pb further increased after 20-day incubation under oxic conditions. The concentration of phosphorus that was extracted by 0.5 M HCl or 0.03 M NH4F in 0.025 M HCl increased under anoxic conditions and decreased under oxic conditions. When Pb-binding to phosphorus is considered during kinetic modeling, the simulated results of Pb transformation suggest that phosphorus is more important than organic matter for Pb immobilization under anoxic conditions, while the phosphates, Fe-Mn oxides, and sulfides immobilized Pb is slowly released and then complexed by fulvic acids during the re-immobilization of dissolved organic matter in soil under oxic conditions. The model established with low Pb level has been successfully applied to describe the Pb transformation with high Pb level. This study provides a comprehensive understanding of the roles of phosphorus and organic matter in controlling Pb transformation in soil from kinetic modeling.
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Affiliation(s)
- Hansha Lu
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China; School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Yang Yang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Kaiyi Huang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China; School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Guoyong Huang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Shiwen Hu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Dandan Pan
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China.
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He C, He X, Yuan R, Li N, Jiang J. Binding characteristics of Pb and Zn to low-temperature feces-based biochar-derived DOM revealed by EEM-PARAFAC combined with general and moving-window two-dimensional correlation analyses. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:27525-27538. [PMID: 36380180 DOI: 10.1007/s11356-022-24132-z] [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: 07/13/2022] [Accepted: 11/05/2022] [Indexed: 06/16/2023]
Abstract
Pyrolysis carbonization of human feces has shown potential for converting feces biomass into a soil amendment. However, little is known about the interactions of DOM derived from feces-based biochar produced at low-temperature with heavy metals (HMs). In this study, the binding properties of Pb(II) and Zn(II) with DOM derived from feces-based biochar produced at low pyrolysis temperatures were investigated using EEM-PARAFAC combined with general, and moving-window two-dimensional correlation analyses (2D-COS). The results revealed that DOM from biochar produced at 280 °C exhibited a higher Pb(II) and Zn(II) affinity and more binding sites than DOM produced at 380 °C. The fulvic-like and humic-like components exhibited obvious fluorescence quenching after the heavy metal addition, and the complexes formed with Pb(II) and Zn(II) were more stable. C-H groups exhibited the fastest response to Pb(II) and Zn(II) binding in the FB280 DOM, while the COO- groups of carboxylic acids in the FB380 DOM exhibited the fastest response to Pb(II) and Zn(II). Moreover, the mutation concentration range of components and functional groups in DOM, as analyzed by MW2D-COS, was greater for Zn(II) than for Pb(II). These results provide a more detailed molecular-level understanding of the interaction mechanisms between heavy metals and feces-based biochar-derived DOM and the effect of HM concentration on DOM binding. Further, these results will help to provide a reasonable reference for feces management and feces-based biochar in controlling soil HMs.
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Affiliation(s)
- Changjun He
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environment Sciences, Beijing, 100012, China
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, China
| | - Xuwen He
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, China
| | - Run Yuan
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, China
| | - Na Li
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing, 100083, China
| | - Jinyuan Jiang
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environment Sciences, Beijing, 100012, China.
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6
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Can Pressmud Improve Nickel Availability in Lead Contaminated Soils ? NATIONAL ACADEMY SCIENCE LETTERS 2022. [DOI: 10.1007/s40009-022-01160-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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7
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Wu B, Guo S, Zhang M, Chen C, Zhang Y. Coupling Effects of combined thermal desorption and stabilisation on stability of cadmium in the soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 310:119905. [PMID: 35961569 DOI: 10.1016/j.envpol.2022.119905] [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: 06/23/2022] [Revised: 07/21/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Combined thermal desorption and stabilisation is a major choice for the remediation of soil polluted by heavy metals and organic toxicants. Coupled, these processes physically and chemically affect the stability of heavy metals. For this study, polluted soil containing cadmium (Cd) around a lead-zinc smelter was chosen as the subject. To determine the coupling influence of combining thermal desorption and stabilisation to stabilise the Cd in the soil, the stability of Cd in the soil after thermal desorption, stabilisation, and combined treatment was examined based on the leaching rate, chemical speciation, and soil microstructure. The results showed that the stability of Cd was directly related to the temperature of thermal desorption and the stabilisation agent dose. The influence of the two combined stabilisation‒thermal desorption and thermal desorption‒stabilisation processes on the stability of Cd was analysed. The proportion of residual Cd of the former was 1.14 times higher than those of the latter, and the soil particles in the former process crystalized more significantly than those in the latter. Multiple regression analysis was used to construct the Cd stability model. In order to make the stabilised fraction of Cd consistent, compared with the stabilisation‒thermal desorption process, the agent dose in the thermal desorption‒stabilisation process should increase by 1.39-5.55 times higher, or the desorption temperature should increase by 28.3 °C-69.5 °C. Therefore, the combined stabilisation‒thermal desorption process is more conducive to stabilising Cd in the soil, a phenomenon that saves energy and reduces carbon emissions.
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Affiliation(s)
- Bo Wu
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, PR China
| | - Shuhai Guo
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, PR China; National-Local Joint Engineering Laboratory of Contaminated Soil Remediation By Bio-physicochemical Synergistic Process, Shenyang, 110016, PR China.
| | - Meng Zhang
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, PR China
| | - Chi Chen
- School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang, 110168, PR China
| | - Yunlong Zhang
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, PR China
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Xu DM, Fu RB. A typical case study from smelter-contaminated soil: new insights into the environmental availability of heavy metals using an integrated mineralogy characterization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:57296-57305. [PMID: 35352226 DOI: 10.1007/s11356-022-19823-6] [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: 01/27/2022] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Mineralogy was an important driver for the environmental release of heavy metals. Therefore, the present work was conducted by coupling mineral liberation analyzer (MLA) with complementary geochemical tests to evaluate the geochemical behaviors and their potential environmental risks of heavy metals in the smelter contaminated soil. MLA analysis showed that the soil contained 34.0% of quartz, 17.15% of biotite, 1.36% of metal sulfides, 19.48% of metal oxides, and 0.04% of gypsum. Moreover, As, Pb, and Zn were primarily hosted by arsenopyrite (29.29%), galena (88.41%), and limonite (24.15%), respectively. The integrated geochemical results indicated that among the studied metals, Cd, Cu, Mn, Pb, and Zn were found to be more bioavailable, bioaccessible, and mobile. Based on the combined mineralogical and geochemical results, the environmental release of smelter-driven elements such as Cd, Cu, Mn, Pb, and Zn were mainly controlled by the acidic dissolution of minerals with neutralizing potential, the reductive dissolution of Fe/Mn oxides, and the partial oxidation of metal sulfide minerals. The present study results have confirmed the great importance of mineralogy analysis and geochemical approaches to explain the contribution of smelting activities to soil pollution risks.
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Affiliation(s)
- Da-Mao Xu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China
- Centre for Environmental Risk Management and Remediation of Soil and Groundwater, Tongji University, Shanghai, 200092, People's Republic of China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China
| | - Rong-Bing Fu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
- Centre for Environmental Risk Management and Remediation of Soil and Groundwater, Tongji University, Shanghai, 200092, People's Republic of China.
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China.
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Wu Y, Yang H, Wang M, Sun L, Xu Y, Sun G, Huang Q, Liang X. Immobilization of soil Cd by sulfhydryl grafted palygorskite in wheat-rice rotation mode: A field-scale investigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 826:154156. [PMID: 35231515 DOI: 10.1016/j.scitotenv.2022.154156] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/11/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
The safe utilization of heavy metal contaminated farmland has attracted extensive attention of the whole society, and there is an urgent need to develop novel high-efficiency amendments. To clarify the actual remediation effect and potential for large-scale application of sulfhydryl grafted palygorskite (SGP) in Cd polluted soil in wheat-rice rotation mode, a field-scale experiment was conducted. SGP at the dosages of 0.5 g/kg-2.0 g/kg could reduce gain Cd contents by 27.15-59.05% and 16.16-79.47% for wheat and rice, respectively. The maximal decreases of soil available Cd figured out by DTPA extraction in wheat and rice season were 58.18% and 33.67%, respectively. The immobilization ratio for Cd was much more than that of trace elements, including Fe, Mn, Cu, and Zn, Ni. SGP showed an effective immobilization rate for soil Cd under the interference of many elements in the soil, pointing to the targeting and selectivity of its high-efficiency immobilization. It had no lifting effect on soil pH but decreased zeta potentials of soil particles. The sorption of Cd2+ on SGP amended soil could be fitted by the second-order kinetic model and Langmuir isotherm, and the changes of thermodynamic parameters showed SGP strengthened the fixation. SGP made the biological accumulation coefficient and transfer factor of rice grain drop dramatically but had no noticeable effect on these parameters of winter wheat, indicating different botanical responses. SGP as a novel immobilization amendment may provide an efficient and sustainable solution for the remediation of contaminated soil in wheat-rice rotation mode in field-scale.
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Affiliation(s)
- Yiqian Wu
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China; School of Engineering and Technology, Tianjin Agricultural University, Tianjin 300392, PR China
| | - Huimin Yang
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Miao Wang
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Lu Sun
- College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, PR China
| | - Yingming Xu
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Guohong Sun
- School of Engineering and Technology, Tianjin Agricultural University, Tianjin 300392, PR China.
| | - Qingqing Huang
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China
| | - Xuefeng Liang
- Key Laboratory of Original Environmental Pollution Control of MARA, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, PR China.
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Abstract
Coal slurry is an essential component of mining operations, accounting for more than half of operating costs. Dewatering technology is simultaneously confronted with obstacles and possibilities, and it may yet be improved as the crucial step for reducing the ultimate processing cost. Coagulation/flocculation is used as a dewatering process that is reasonably cost-effective and user-friendly. This paper reviews application of different coagulants/flocculants and their combinations in dewatering mechanisms. In this context, various polymeric flocculants are discussed in the coal slurry in depth. Many operational parameters that influence the performance of coal slurry flocculation are also presented. Furthermore, a discussion is provided on the mechanism of flocculants’ interaction, the strategy of combining flocculants, and efficient selection methods of flocculants. Finally, coagulation/flocculation remaining challenges and technological improvements for the better development of highly efficient treatment methods were highlighted, focusing on the intricate composition of slurry and its treatment difficulties.
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