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Yang Z, Xia H, Guo Z, Xie Y, Liao Q, Yang W, Li Q, Dong C, Si M. Development and application of machine learning models for prediction of soil available cadmium based on soil properties and climate features. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 355:124148. [PMID: 38735457 DOI: 10.1016/j.envpol.2024.124148] [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: 03/07/2024] [Revised: 04/18/2024] [Accepted: 05/09/2024] [Indexed: 05/14/2024]
Abstract
Identifying the key influencing factors in soil available cadmium (Cd) is crucial for preventing the Cd accumulation in the food chain. However, current experimental methods and traditional prediction models for assessing available Cd are time-consuming and ineffective. In this study, machine learning (ML) models were developed to investigate the intricate interactions among soil properties, climate features, and available Cd, aiming to identify the key influencing factors. The optimal model was obtained through a combination of stratified sampling, Bayesian optimization, and 10-fold cross-validation. It was further explained through the utilization of permutation feature importance, 2D partial dependence plot, and 3D interaction plot. The findings revealed that pH, surface pressure, sensible heat net flux and organic matter content significantly influenced the Cd accumulation in the soil. By utilizing historical soil surveys and climate change data from China, this study predicted the spatial distribution trend of available Cd in the Chinese region, highlighting the primary areas with heightened Cd activity. These areas were primarily located in the eastern, southern, central, and northeastern China. This study introduces a novel methodology for comprehending the process of available Cd accumulation in soil. Furthermore, it provides recommendations and directions for the remediation and control of soil Cd pollution.
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Affiliation(s)
- Zhihui Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083, Changsha, China
| | - Hui Xia
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Ziyun Guo
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Yanyan Xie
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Qi Liao
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083, Changsha, China
| | - Weichun Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083, Changsha, China
| | - Qingzhu Li
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083, Changsha, China
| | - ChunHua Dong
- Soil and Fertilizer Institute of Hunan Province, 410125, Changsha, China
| | - Mengying Si
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, 410083, Changsha, China.
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Yuan Z, Peng A, Chu Z, Zhang X, Huang H, Mi Y, Xia D, Wu X, Ye Z, Tao Y, Yan X. Sustainable remediation of Cr(VI)-contaminated soil by soil washing and subsequent recovery of washing agents using biochar supported nanoscale zero-valent iron. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171107. [PMID: 38387560 DOI: 10.1016/j.scitotenv.2024.171107] [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: 09/30/2023] [Revised: 01/31/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
Soil contamination by Cr(VI) has attracted widespread attention globally in recent years, but it remains a significant challenge in developing an environmentally friendly and eco-sustainable technique for the disposal of Cr(VI)-contaminated soil. Herein, a sustainable cyclic soil washing system for Cr(VI)-polluted soil remediation and the recovery of washing agents using biochar supported nanoscale zero-valent iron (nZVI-BC) was established. Citric acid (CA) was initially screened to desorb Cr(VI) from contaminated soil, mobilizing Cr from the highly bioaccessible fractions. The nZVI-BC exhibited superior properties for Cr(VI) and Cr(total) removal from spent effluent, allowing effective recovery of the washing agents. The elimination mechanism of Cr(total) by nZVI-BC involved the coordinated actions of electrostatic adsorption, reduction, and co-precipitation. The contributions to Cr(VI) reduction by Fe0, surface-bound Fe(II), and soluble Fe(II) were 0.6 %, 39.8 %, and 59.6 %, respectively. Meanwhile, CA favored the activity of surface-bound Fe(II) and Fe0 in nZVI-BC, enhancing the production of soluble Fe(II) to strengthen Cr(VI) removal. Finally, the recovered washing agent was proven to be reused three times. This study showcases that the combined soil washing using biodegradable chelant CA and effluent treatment by nZVI-BC could be a sustainable and promising strategy for Cr(VI)-contaminated soil remediation.
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Affiliation(s)
- Zhe Yuan
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - Aifang Peng
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - Zhaopeng Chu
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - Xinyi Zhang
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - He Huang
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - Yuanzhu Mi
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China
| | - Dongsheng Xia
- Engineering Research Center of Ministry of Education for Clean Production of Textile Printing and Dyeing, Wuhan 430200, China
| | - Xiaogang Wu
- School of Urban Construction, Yangtze University, Jingzhou 434103, PR China
| | - Zhihong Ye
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400000, China
| | - Yufang Tao
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China.
| | - Xuemin Yan
- College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou 434023, PR China.
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Guo J, Wang D, Shi Y, Lyu H, Tang J. Minor chromium passivation of S-ZVI enhanced the long-term dechlorination performance of trichlorethylene: Effects of corrosion and passivation on the reactivity and selectivity. WATER RESEARCH 2024; 249:120973. [PMID: 38071903 DOI: 10.1016/j.watres.2023.120973] [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: 08/31/2023] [Revised: 11/14/2023] [Accepted: 12/03/2023] [Indexed: 01/03/2024]
Abstract
The corrosion and surface passivation of sulfidized zero-valent iron (S-ZVI) by common groundwater ions and contaminants are considered to be the most challenging aspects in the application of S-ZVI for remediation of chlorinated contaminants. This study investigated the impacts of corrosive chloride (Cl-) and passivation of hexavalent chromium (Cr(VI)) on the long-term reactivity, selectivity, corrosion behavior, and physicochemical properties during the 60-day aging process of S-ZVI. Although the co-existing of Cl- promoted the initial reactivity of S-ZVI, the rapid consumption of Fe° content shortened the reactive lifetime owing to the insufficient electron capacity. Severe passivation by Cr(VI) (30 mg L-1) preserved the Fe° content but significantly interfered with the reductive sulfur species, resulting in an increase in electron transfer resistance. In comparison, minor passivated S-ZVI (5.0 mg L-1 Cr(VI)) inhibited the hydrogen evolution while concurrently mitigating the further oxidation of the reductive iron and sulfur species, which significantly enhanced the long-term reactivity and selectivity of S-ZVI. Furthermore, the enhancement effect of minor passivation could be detected in the aging processes of one-step, two-step, and mechanochemically synthesized S-ZVI particles with different S/Fe ratios and precursors, which further verified the advantages of minor passivation. This observation is inspirable for the development of innovative strategies for environmental remediation by S-ZVI-based materials.
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Affiliation(s)
- Jiaming Guo
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Dong Wang
- Environmental Protection Institute, SINOPEC Beijing Research Institute of Chemical Industry, Beijing 100013, China
| | - Yinghao Shi
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Honghong Lyu
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
| | - Jingchun Tang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
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