Coupled sorptive and oxidative antimony(III) removal by iron-modified biochar: Mechanisms of electron-donating capacity and reactive Fe species

Yurong Gao, Hanbo Chen, Zheng Fang, Nabeel Khan Niazi, Kwasi Adusei-Fosu, Jianhong Li, Xing Yang, Zhongzhen Liu, Nanthi S Bolan, Bin Gao, Deyi Hou, Chenghua Sun, Jun Meng, Wenfu Chen, Bert F Quin, Hailong Wang

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Abstract

Sorption and oxidation are two potential pathways for the decontamination of trivalent antimony (Sb(III))-bearing water, using iron (Fe)-modified biochar (FeBC). Here we investigated the sorption and oxidation behavior of FeBC for Sb(III) in aqueous solutions. Results revealed that Sb(III) removal by FeBC was significantly improved showing the maximum Sb(III) sorption (64.0 mg g -1). Density functional theory (DFT) calculations indicated that magnetite (Fe 3O 4) in FeBC offered a sorption energy of -0.22 eV, which is 5 times that of non-modified biochar. With the addition of peroxymonosulfate (PMS), the sorption of Sb(III) on FeBC was 7 times higher than that on BC, indicating the sorption capacity of FeBC for Sb(III) could be substantially increased by adding oxidizing agents. Electrochemical analysis showed that Fe modification imparted FeBC higher electron-donating capacity than that of BC (0.045 v. s. 0.023 mmol e - (g biochar) -1), which might be the reason for the strong Sb(III) oxidation (63.6%) on the surface of FeBC. This study provides new information that is key for the development of effective biochar-based composite materials for the removal of Sb(III) from drinking water and wastewater. The findings from this study have important implications for protecting human health and agriculture.

Original languageEnglish
Article number122637
JournalEnvironmental Pollution
Volume337
DOIs
Publication statusPublished - 15 Nov 2023

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