Novel magnetic adsorbents based on oyster and clam shells for the removal of cadmium in soil.

Autor: Wang H; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China., Fu Y; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China., Guo K; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China., Li X; School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, PR China., Jin X; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China., Huang Y; Guangdong Yuegang Water Supply Co. Ltd., Shenzhen 518021, PR China., Wang X; Guangdong Yuegang Water Supply Co. Ltd., Shenzhen 518021, PR China., Lu G; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China., Yi X; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China. Electronic address: xyyi@scut.edu.cn., Dang Z; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Dec 10; Vol. 955, pp. 177083. Date of Electronic Publication: 2024 Oct 31.
DOI: 10.1016/j.scitotenv.2024.177083
Abstrakt: Magnetic adsorbents can effectively remove heavy metals from soil. However, the magnetization process may reduce availability of adsorption sites, making it challenging to balance magnetic and adsorption properties. In this study, oyster shell (OS) and clam shell (CS) material was magnetized by an improved chemical co-precipitation method. The organic matter in the shells was destroyed by calcination modification to expose new active sites, and calcinated ferro-magnetic adsorbent was produced with either ferrosodium EDTA (giving CEOS and CECS) or with iron citrate (for CCOS and CCCS). All four modified adsorbents reached adsorption equilibrium for Cd 2+ in solution within 120 min, with maximum adsorption capacities ranging from 115.5 to 266.5 mg/g, giving high removal efficiencies for Cd 2+ . Adsorption by precipitation and cation exchange mechanisms was dominant, together contributing >60 % of all adsorption capacity, followed by complexation. When used for remediation of Cd-contaminated soil, CEOS demonstrated the best Cd removal efficiency, achieving removal rates of 46 % and 58 % for total and available Cd, respectively. This was mainly because CEOS had the highest magnetic recovery rate, of 98 %. CEOS maintained removal rates of 34 % for total Cd after regeneration and reuse three cycles, with recovery rates remaining above 90 %. Contaminated soil was treated with the novel adsorbents and in pot experiments with water spinach cultivation it was shown that both CEOS and CECS treatment significantly reduced Cd content (by up to 56 %). The magnetic adsorbents presented here demonstrate excellent performance to remove Cd from water and soil, and have promising application prospects.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier B.V.)
Databáze: MEDLINE
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