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Rape Straw Biochar Application Enhances Cadmium Immobilization by Promoting Formation of Sulfide and Poorly Crystallized Fe Oxide in Paddy Soils.

Authors :
Yuan, Rui
Si, Tianren
Lu, Qingquan
Liu, Cheng
Bian, Rongjun
Liu, Xiaoyu
Zhang, Xuhui
Zheng, Jufeng
Cheng, Kun
Joseph, Stephen
Wang, Yan
Li, Lianqing
Pan, Genxing
Source :
Agronomy. Nov2023, Vol. 13 Issue 11, p2693. 15p.
Publication Year :
2023

Abstract

The mechanisms of rape straw biochar that affect the fixation of cadmium (Cd) in paddy soil by influencing redox of iron and sulfur are unclear. Several anaerobic incubation experiments were carried out using Cd-contaminated paddy soils (LY and ZZ). Rape straw biochar at pyrolysis temperatures of 450 °C (LRSB) and 800 °C (HRSB) was selected as the soil remediation agent. The electron exchange capacity and electrical conductivity were higher in HRSB than those in LRSB. The lower pe + pH in HRSB enhanced Fe oxide reduction, with a maximum increase in Fe2+ of 46.0% in ZZ. Compared to treatment without biochar (CK), the poorly crystallized Fe oxide (Feo) in HRSB increased by 16.8% in ZZ. This induced Cd bound to Fe, and Mn oxides fraction (Fe-Mn Cd) increased by 42.5%. The SO42−-S content in LRSB was 4.6 times that of HRSB. LRSB addition increased acid-volatile sulfide by 46.4% and 48.9% in LY and ZZ soils, respectively, compared to CK. This resulted in an increase in sulfide's contribution to Cd fixation, with values rising from 24.2% to 37.8% in LY and 19.1% to 29.8% in ZZ. Overall, LRSB reduced Cd mobility by forming more sulfide, while HRSB increased Fe-Mn Cd by increasing Feo. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20734395
Volume :
13
Issue :
11
Database :
Academic Search Index
Journal :
Agronomy
Publication Type :
Academic Journal
Accession number :
173829470
Full Text :
https://doi.org/10.3390/agronomy13112693