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Liu G, Tu C, Li Y, Yang S, Wang Q, Wu X, Zhou T, Luo Y. Rapidly reducing cadmium from contaminated farmland soil by novel magnetic recyclable Fe 3O 4/mercapto-functionalized attapulgite beads. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 351:124056. [PMID: 38677464 DOI: 10.1016/j.envpol.2024.124056] [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: 12/31/2023] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
Reducing cadmium (Cd) content from contaminated farmland soils remains a major challenge due to the difficulty in separating commonly used adsorbents from soils. This study synthesized novel millimeter-sized magnetic Fe3O4/mercapto-functionalized attapulgite beads (MFBs) through a facile one-step gelation process incorporating alginate. The MFBs inherit the environmental stability of alginate and enhance its mechanical strength by hybridizing Fe3O4 and clay mineral components. MFBs can be easily separated from flooded soils by magnets. When applied to 12 Cd-polluted paddy soils and 14 Cd-polluted upland soils, MFBs achieved Cd(II) removal rates ranging from 16.9% to 62.2% and 9.8%-54.6%, respectively, within a 12-h period. The MFBs predominantly targeted the exchangeable and acid soluble, and reducible fractions of Cd, with significantly enhanced removal efficiencies in paddy soils compared to upland soils. Notably, MFBs exhibited superior adsorption performance in soils with lower pH and organic matter (OM) content, where the bioavailability and mobility of Cd are heightened. The reduction of Cd content by MFBs is a sustainable and safe method, as it permanently removes the bioavailable Cd from soil, rather than temporarily reducing its bioavailability. The functional groups such as -SH, -OH, present in attapulgite and alginate of MFBs, played a crucial role in Cd(II) adsorption. Additionally, attapulgite and zeolite provided a porous matrix structure that further enhanced Cd(II) adsorption. The results of X-ray photoelectron spectroscopy suggested that both chemical precipitation and surface complexation contributed to Cd(II) removal. The MFBs maintained 87.6% Cd removal efficiency after 5 regeneration cycles. The surface of the MFBs exposed new adsorption sites and increased the specific surface area during multiple cycles with Cd-contaminated soil. This suggests that MFBs treatment with magnetic retrieval is a potentially effective pathway for the rapid removal of Cd from contaminated farmland soils.
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Affiliation(s)
- Guoming Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Chen Tu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yuan Li
- CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences, Yantai 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, China
| | - Shuai Yang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Qihao Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xinyou Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tong Zhou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yongming Luo
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
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Sun Y, Chen S, Jiang H, Qin B, Li D, Jia K, Wang C. Towards interpretable machine learning for observational quantification of soil heavy metal concentrations under environmental constraints. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171931. [PMID: 38531447 DOI: 10.1016/j.scitotenv.2024.171931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/18/2024] [Accepted: 03/21/2024] [Indexed: 03/28/2024]
Abstract
Monitoring heavy metal concentrations in soils is central to assessing agricultural production safety. Satellite observations permit inferring concentrations from spectrum, thereby contributing to the prevention and control of soil heavy metal pollution. However, heavy metals exhibit weak spectral responses, particularly at low and medium concentrations, and are predominantly influenced by other soil components. Machine learning (ML)-driven modelling can produce predictions but lacks interpretability. Here, we present an interpretable ML framework for concentration quantification modelling and investigated the contributions of spectral and environmental factors-pH and organic carbon-to the estimation of metals with multiple concentration gradients, as analysed through SHAP (SHapley Additive exPlanations) data derived from four learning-based scenarios. The results indicated that scenarios SHC (spectral, pH, and organic carbon) and SH (spectral and pH) were the most optimal for chromium (Cr) [RPD = 1.42, Adj R2 = 0.62], and cadmium (Cd) [RPD = 1.80, Adj R2 = 0.80]. Under environmental constraints, the spectral predictability for Cr and Cd was improved by 67 % and 87 %, respectively. We concluded that interpretable modelling, utilising both spectral and soil environmental factors, holds significant potential for estimating heavy metals across concentration gradients. It is recommended that samples with higher organic carbon content and lower pH be selected to enhance Cr and Cd predictions. An advanced grasp of interpretable predictions facilitates earlier warning of heavy metal contamination and guides the formulation of robust sampling strategies.
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Affiliation(s)
- Yishan Sun
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuisen Chen
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China; Joint Laboratory on Low-carbon Digital Monitoring, Guangdong Institute of Carbon Neutrality (Shaoguan), Shaoguan ShenBay Low Carbon Digital Technology Co., Ltd., Shaoguan 512026, China.
| | - Hao Jiang
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China
| | - Boxiong Qin
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China; Joint Laboratory on Low-carbon Digital Monitoring, Guangdong Institute of Carbon Neutrality (Shaoguan), Shaoguan ShenBay Low Carbon Digital Technology Co., Ltd., Shaoguan 512026, China
| | - Dan Li
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China; Joint Laboratory on Low-carbon Digital Monitoring, Guangdong Institute of Carbon Neutrality (Shaoguan), Shaoguan ShenBay Low Carbon Digital Technology Co., Ltd., Shaoguan 512026, China
| | - Kai Jia
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China; Joint Laboratory on Low-carbon Digital Monitoring, Guangdong Institute of Carbon Neutrality (Shaoguan), Shaoguan ShenBay Low Carbon Digital Technology Co., Ltd., Shaoguan 512026, China
| | - Chongyang Wang
- Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System, Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangdong Engineering Technology Research Center of Remote Sensing Big Data Application, Guangzhou Institute of Geography, Guangdong Academy of Science, Guangzhou 510070, China
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Li H, Yao J, Sunahara G, Min N, Li C, Duran R. Quantifying ecological and human health risks of metal(loid)s pollution from non-ferrous metal mining and smelting activities in Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162364. [PMID: 36828070 DOI: 10.1016/j.scitotenv.2023.162364] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
The environmental release and transfer of heavy metal(loids) from natural and anthropogenic sources to neighboring habitats can pose an ecological threat to the exposed biota and habitat, as well as a human health risk to the residents. However, analytical tools to identify the potential contamination source(s) and assess the impact of this transfer have not been well described. Soil samples were collected from affected areas proximal to non-ferrous metal(loid)s mining and smelting facilities. Two integrated assessment methods, based on soil total metal(loid) content, included: (1) the potential ecological risk index combined with positive matrix factorization (PMF) and (2) human health risk assessment combined with PMF. Results indicated that there were four generic sources of pollution (based on PMF analyses of 115 replicated samples collected from four study areas): agricultural and industrial activities, traffic emissions, and natural sources. For ecological risk, the contribution of these metal(loid)s pollution sources were industrial activities (20.34-70.76 %), traffic emissions (18.73-56.93 %), natural sources (3.69-27.02 %), and agricultural activities (3.79-21.43 %). Health risks were higher for children than for adults. Industrial activity was a major source of non-carcinogenic risk to children (32.10-74.62 %) and adults (31.33-73.78 %), and carcinogenic risk to children (22.53-67.27 %) and adults (20.69-64.76 %). Total metal analysis indicated that As and Cd were highly enriched in the soil, but chemical fractionation revealed low As mobility. Total Cd and possibly As were the main pollutants causing the ecological risks at these contaminated sites. This study demonstrates that ecological and human health risks could be quantified to prioritize the pollution sources for reasonable contaminated site risk management.
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Affiliation(s)
- Hao Li
- School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China
| | - Jun Yao
- School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China.
| | - Geoffrey Sunahara
- School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China; Department of Natural Resource Sciences, McGill University, 21111, Lakeshore Drive, Ste-Anne-de-Bellevue, Quebec H9X 3V9, Canada
| | - Ning Min
- School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China
| | - Chenchen Li
- Faculty of Metallurgy and Energy Engineering, National and Local Joint Engineering Laboratory for Lithium-ion Batteries and Materials Preparation Technology, Key Laboratory of Advanced Battery Materials or Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China
| | - Robert Duran
- School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China; Equipe Environnement et Microbiologie, MELODY group, Université de Pau et des Pays de l'Adour, E2S-UPPA, IPREM UMR CNRS 5254, BP 1155, 64013 Pau Cedex, France
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Gao Y, Duan Z, Zhang L, Sun D, Li X. The Status and Research Progress of Cadmium Pollution in Rice- ( Oryza sativa L.) and Wheat- ( Triticum aestivum L.) Cropping Systems in China: A Critical Review. TOXICS 2022; 10:794. [PMID: 36548627 PMCID: PMC9783001 DOI: 10.3390/toxics10120794] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/07/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
The accumulation of cadmium in rice (Oryza sativa L.) and wheat (Triticum aestivum L.) is a serious threat to the safe use of farmland and to the health of the human diet that has attracted extensive attention from researchers. In this review, a bibliometric analysis was performed using a VOS viewer (1.6.18, Netherlands) to investigate the status of cadmium contamination in rice and wheat growing systems, human health risks, mechanisms of Cd uptake and transport, and the corresponding research hotspots. It has a certain reference value for the prevention and control of cadmium pollution in rice and wheat planting systems in China and abroad. The results showed that the Cd content in rice and wheat planting systems in the Yangtze River Basin was significantly higher than that in other areas of China, and the Cd content in rice and wheat grains and the hazard quotient (HQ) in Hunan Province was the highest. The average Cd concentration exceeded the recommended limit by about 62% for rice and 81% for wheat. The main reasons for the high Cd pollution in rice and wheat growing areas in Hunan are mining activities, phosphate fertilizer application, sewage irrigation, and electronic equipment manufacturing. In this review, we demonstrate that cadmium toxicity reduces the uptake and transport of essential elements in rice and wheat. Cadmium stress seriously affected the growth and morphology of plant roots. In the shoots, Cd toxicity was manifested by a series of physiological injuries, such as decreased photosynthesis, soluble protein, sugar, and antioxidant enzyme activity. Cadmium that accumulates in the shoots is transferred to grains and then passes up the food chain to people and animals. Therefore, methods for reducing cadmium content in grains of rice and wheat are urgently needed, especially in Cd-contaminated soil. Current research on Cd pollution in rice and wheat planting systems focuses on the bioavailability of Cd, soil rhizosphere changes in wheat and rice, and the role of antioxidant enzyme systems in alleviating heavy metal stress in rice and wheat.
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Affiliation(s)
- Yue Gao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zengqiang Duan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingxiao Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Da Sun
- Technology Extension Station of Agriculture and Fisheries of Nanhu District of Jiaxing, Jiaxing 314051, China
| | - Xun Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Pan H, Huang W, Wu L, Hong Q, Hu Z, Wang M, Zhang F. A pH Dual-Responsive Multifunctional Nanoparticle Based on Mesoporous Silica with Metal-Polymethacrylic Acid Gatekeeper for Improving Plant Protection and Nutrition. NANOMATERIALS 2022; 12:nano12040687. [PMID: 35215015 PMCID: PMC8875777 DOI: 10.3390/nano12040687] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 12/16/2022]
Abstract
Integrating pesticides and mineral elements into a multi-functional stimuli-responsive nanocarrier can have a synergistic effect on protecting plants from pesticides and the supply of nutrients. Herein, a pH dual-responsive multifunctional nanosystem regulated by coordination bonding using bimodal mesoporous silica (BMMs) as a carrier and coordination complexes of ferric ion and polymethacrylic acid (PMAA/Fe3+) as the gatekeeper was constructed to deliver prochloraz (Pro) for the smart treatment of wilt disease (Pro@BMMs−PMAA/Fe3+). The loading capacity of Pro@BMMs−PMAA/Fe3+ nanoparticles (Nps) was 24.0% and the “PMMA/Fe3+” complexes deposited on the BMMs surface could effectively protect Pro against photodegradation. The nanoparticles possessed an excellent pH dual-responsive release behavior and better inhibition efficacy against Rhizoctonia solani. Fluorescence tracking experiments showed that Nps could be taken up and transported in fungi and plants, implying that non-systemic pesticides could be successfully delivered into target organisms. Furthermore, BMMS−PMAA/Fe3+ nanocarriers could effectively promote the growth of crop seedlings and had no obvious toxicological influence on the cell viability and the growth of bacteria. This study provides a novel strategy for enhancing plant protection against diseases and reducing the risk to the environment.
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Zou M, Zhou S, Zhou Y, Jia Z, Guo T, Wang J. Cadmium pollution of soil-rice ecosystems in rice cultivation dominated regions in China: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 280:116965. [PMID: 33774546 DOI: 10.1016/j.envpol.2021.116965] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 05/22/2023]
Abstract
Cd accumulation in paddy soils and its subsequent transfer to the food chain are widespread environmental issues, which has been extensively investigated in China. However, most studies focused on regional scales and these results may not be applicable to present the Cd contamination status in soil-rice ecosystems at a national scale. Therefore, based on collected data from China's rice cultivation dominated regions, this study provides the Cd pollution level of paddy soils and rice grains in China. Results indicates that the Yangtze River basin, especially Hunan, required more attention due to the elevated Cd concentrations in soil-rice ecosystems. Moreover, this review summarizes the significant natural and anthropogenic sources, transport and accumulation mechanism as well as the influencing factors of Cd in soil-rice ecosystems. The wide occurrence of Cd contamination in paddy soils derived primarily from mining activities, intensive application of phosphates fertilizers and e-waste. Physicochemical characteristics of soil, soil microorganisms, temperature as well as the physiological features of rice plants all contribute to Cd accumulation in rice grains, which can be controlled to mitigate Cd accumulation in rice grains. This review will provide a scientific reference for Cd pollution control and management with respect to paddy field ecosystems in China and other countries.
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Affiliation(s)
- Mengmeng Zou
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China
| | - Shenglu Zhou
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China.
| | - Yujie Zhou
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China
| | - Zhenyi Jia
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China
| | - Tianwei Guo
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China
| | - Junxiao Wang
- School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; Key Laboratory of Coastal Zone Exploitation and Protection, Ministry of Natural Resources, Nanjing, 210024, China
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Dong H, Yoneda M, Feng L. Risk dynamic evolution index based on fraction transformation and its application to site risk assessment. JOURNAL OF HAZARDOUS MATERIALS 2021; 412:125210. [PMID: 33529833 DOI: 10.1016/j.jhazmat.2021.125210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
In this study, a potential ecological risk index for site dynamic risk evolution was proposed with the development trend of the Hakanson approach. The possibility factor Pi was attached to the contamination factor Cfi, representing the burst probability factor of dynamic risk arising from the transformation of metal(loid) fractions, ascertained by the delayed geochemical hazard (DGH) methodology. The toxic effects of different elements were explored through a meta-analysis. The effects of soil pH and soil organic matter on the mobile fraction of elements were examined, and the toxic factors (Tri) of six elements (arsenic, cadmium, chromium, copper, lead, and zinc) were modified for the site application. A total of 16 case studies representing four soil types (agricultural soil, industrial zone, mining area, and soil of river basin) were tested, and the results indicated that the proposed index could provide an early warning of site risk dynamics.
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Affiliation(s)
- Haochen Dong
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan; Department of Environmental Sciences and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Minoru Yoneda
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan
| | - Liu Feng
- Department of Environmental Sciences and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
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Mao Y, Fan W, Yan Y, Xiang W, Hu S, Yan S. Cd Adsorption by Iron-Organic Associations: Implications for Cd Mobility and Fate in Natural and Contaminated Environments. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 106:109-114. [PMID: 32789673 DOI: 10.1007/s00128-020-02962-2] [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: 01/18/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
The mobility and fate of Cd in soil are mainly controlled by active substances such as iron minerals and organic matter. Iron minerals and organic matter often coexist in the form of iron-organic associations (IOA), which have large specific surface areas and many functional groups, potentially affecting Cd adsorption. However, little is known about Cd adsorption by IOA. This study investigated Cd adsorption by the synthetic IOA under different conditions. The results indicate Cd adsorption increased with the increasing amount of IOA, while the adsorption efficiency decreased gradually. pH significantly affects Cd adsorption, because the Cd speciation and the surface charge of IOA changed under different pH conditions. Under alkaline condition, part of Cd would form hydroxide precipitate, facilitating Cd adsorption by IOA. The composition of organic matter in IOA didn't significantly affect Cd adsorption.
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Affiliation(s)
- Yijie Mao
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
| | - Weiguo Fan
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
| | - Yaxin Yan
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
| | - Wu Xiang
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
| | - Shenghong Hu
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
| | - Sen Yan
- Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China.
- Zhejiang Institute, China University of Geosciences, Hangzhou, 311305, China.
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