Insight into the enhanced removal of dimethoate by ferrate(Ⅵ)/biochar system: Contributions of adsorption and active oxidants

Lijia Qiu; Rongfang Yuan; Huilun Chen; Zongyu Zhang; Beihai Zhou; Shuai Luo

doi:10.1016/j.jhazmat.2024.136980

Insight into the enhanced removal of dimethoate by ferrate(Ⅵ)/biochar system: Contributions of adsorption and active oxidants

J Hazard Mater. 2024 Dec 24:486:136980. doi: 10.1016/j.jhazmat.2024.136980. Online ahead of print.

Authors

Lijia Qiu¹, Rongfang Yuan², Huilun Chen³, Zongyu Zhang⁴, Beihai Zhou³, Shuai Luo³

Affiliations

¹ Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Haidian District, Beijing 100083, China; Beijing City University, Shunyi District, Beijing 101309, China.
² Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Haidian District, Beijing 100083, China. Electronic address: yuanrongfang@ustb.edu.cn.
³ Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Haidian District, Beijing 100083, China.
⁴ Beijing City University, Shunyi District, Beijing 101309, China.

PMID: 39731889
DOI: 10.1016/j.jhazmat.2024.136980

Abstract

Dimethoate is a toxic organophosphorus insecticide and its contamination of water poses a threat to the surrounding ecosystem. In order to enhance the removal effect of ferrate (Fe(VI)) on dimethoate, modified graphene-like biochar (SIZBC) with reduction and adsorption properties was prepared in this study. Compared with Fe(VI) alone, the removal of dimethoate by Fe(VI)/SIZBC increased from 26 % to more than 97 %, and the reaction rate was accelerated by 34 times. The oxidizing property of Fe(VI) was enhanced by the reducing groups loaded on SIZBC, and more active species were produced with the contributions ranked as SO₄^•¯ > ∙OH > Fe(V). And the contributions of adsorption and active oxidants in the reaction process accounted for 25 % and 75 %, respectively. Enlarging the sulfite solution concentration of modified biochar, the transformation from ∙OH/Fe(V) to SO₄^•¯ was promoted in the system. As the concentration of Fe(Ⅵ) increased, the contributions of ∙OH and SO₄^•¯ gradually decreased and Fe(V) became the main active oxidant. Fe(VI)-induced core/shell nanoparticles exhibited in situ adsorption of phosphate which was a mineralization product of dimethoate, thus total phosphorus (TP) removal was increased by 27 %. Through the three degradation pathways, dimethoate and its toxic intermediates were further mineralized to inorganic substances. Finally, the Fe(VI)/SIZBC system was proven to be feasible for actual water treatment and was able to reduce water toxicity.

Keywords: Dimethoate; Ferrate(Ⅵ); Free radicals; Graphene-like biochar; Intermediate iron species.