Removal of aqueous As(III) Sb(III) by potassium ferrate (K2FeO4): The function of oxidation and flocculation

Ning Wang; Nannan Wang; Li Tan; Ru Zhang; Qian Zhao; Hongbo Wang

doi:10.1016/j.scitotenv.2020.138541

Removal of aqueous As(III) Sb(III) by potassium ferrate (K₂FeO₄): The function of oxidation and flocculation

Sci Total Environ. 2020 Jul 15:726:138541. doi: 10.1016/j.scitotenv.2020.138541. Epub 2020 Apr 7.

Authors

Ning Wang¹, Nannan Wang¹, Li Tan¹, Ru Zhang¹, Qian Zhao¹, Hongbo Wang²

Affiliations

¹ School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China.
² School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China. Electronic address: wanghongbo@sdjzu.edu.cn.

PMID: 32315853
DOI: 10.1016/j.scitotenv.2020.138541

Abstract

This study investigated the effects of potassium ferrate (K₂FeO₄) dosage, pH, and reaction time on the removal of aqueous As(III) and Sb(III), and revealed the oxidation and flocculation mechanism of K₂FeO₄. The results show that the removal efficiencies of As(III) and Sb(III) were highly related to the hydrolysate of K₂FeO₄ under acidic conditions, while the efficiencies were low under alkaline condition, owning to the electrostatic repulsion between iron nanoparticles and charged As/Sb species. The increased dosage and reaction time improved the adsorption performance. Based on the comparative experiments with FeCl₃, the simultaneous removal of As(III) and Sb(III) by K₂FeO₄ suggested that As(III) was eliminated due to the processes of oxidation, flocculation, and chemical precipitation, while Sb(III) was removed mostly by oxidation and flocculation. The generated precipitates were characterized with surface analysis and the results support that the oxidization property of K₂FeO₄ was essential during the removal of As(III) and Sb(III), and removal mechanisms between both elements were different.

Keywords: Antimony; Arsenic; Coagulation; Oxidation; Potassium ferrate.