A two-sorbent system for fast uptake of arsenate from water: Batch and column studies

Zhengyang Wang; Xiangyu Bi; Xiaoqing He; Yunchao Xie; Jian Lin; Baolin Deng

doi:10.1016/j.watres.2022.119290

A two-sorbent system for fast uptake of arsenate from water: Batch and column studies

Water Res. 2023 Jan 1;228(Pt B):119290. doi: 10.1016/j.watres.2022.119290. Epub 2022 Oct 22.

Authors

Zhengyang Wang¹, Xiangyu Bi², Xiaoqing He³, Yunchao Xie⁴, Jian Lin⁴, Baolin Deng⁵

Affiliations

¹ Department of Civil and Environmental Engineering, The University of Missouri, Columbia, MO 65211, USA; Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA.
² Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
³ Electron Microscopy Core Facilities, The University of Missouri, Columbia, MO 65211, USA; Department of Mechanical and Aerospace Engineering, The University of Missouri, Columbia, MO 65211, USA.
⁴ Department of Mechanical and Aerospace Engineering, The University of Missouri, Columbia, MO 65211, USA.
⁵ Department of Civil and Environmental Engineering, The University of Missouri, Columbia, MO 65211, USA. Electronic address: dengb@missouri.edu.

PMID: 36434972
DOI: 10.1016/j.watres.2022.119290

Abstract

There is a critical need to use decentralized and/or point-of-use systems to address some challenging water quality issues in society. Sorption-based approaches are uniquely suitable for such applications because of their simplicity in operation; however, the sorbents must possess fast contaminant uptake kinetics to overcome short hydraulic contact times often encountered in small systems. Here we designed a two-sorbent system consisting of Fe₂O₃-coated mesoporous carbon (FeMC) and nano-Fe₂O₃-coated activated carbon (FeAC) and demonstrated its ability to remove arsenate with a < 1 min empty bed contact time (EBCT) by a capture-and-storage process. Batch experiments showed rapid capture of arsenate by FeMC, likely occurred on the rod-like structures protruding to the liquid film. The captured arsenate could subsequently be relocated to FeAC for storage, which had a higher apparent sorption capacity. Column studies, operated with a 10 h running time followed by a 14 h pump-off time, showed that with a 102 μg-As/L influent concentration and at 0.85 min EBCT, the column treated 20,022 bed volumes until the 10 μg-As/L breakthrough, corresponding to a sorption density of 2.36 mg-As/g. This capture-and-storage technique resulted in a rapid and high-capacity arsenate removal through a combined effect of facile access to sorption sites on one sorbent and dynamic equilibrium in the two-sorbent system possessing a large total sorption capacity.

Keywords: Adsorption; Arsenic; Dialysis; Extraction; Kinetics; Water treatment.

MeSH terms

Arsenates*
Biological Transport
Charcoal*
Kinetics

Substances

arsenic acid
Arsenates
Charcoal