ZVI impregnation altered arsenic sorption by ordered mesoporous carbon in presence of Cr(Ⅵ): A mechanistic investigation

Ni Zhang; Munyabugingo Eric; Changai Zhang; Jian Zhang; Ke Feng; Yuncong Li; Shengsen Wang

doi:10.1016/j.jhazmat.2021.125507

ZVI impregnation altered arsenic sorption by ordered mesoporous carbon in presence of Cr(Ⅵ): A mechanistic investigation

J Hazard Mater. 2021 Jul 15:414:125507. doi: 10.1016/j.jhazmat.2021.125507. Epub 2021 Feb 24.

Authors

Ni Zhang¹, Munyabugingo Eric², Changai Zhang³, Jian Zhang², Ke Feng¹, Yuncong Li⁴, Shengsen Wang⁵

Affiliations

¹ College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225127, PR China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, PR China.
² College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, PR China.
³ School of Environmental and Natural Resources, Zhejiang University of Science & Technology, Hangzhou 310023, PR China.
⁴ Soil and Water Sciences Department, Tropical Research and Education Center, IFAS, University of Florida, Homestead FL 33031, USA.
⁵ College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, PR China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225127, PR China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, PR China. Electronic address: wangss@yzu.edu.cn.

PMID: 34030402
DOI: 10.1016/j.jhazmat.2021.125507

Abstract

It is challenging to efficiently remove arsenate (As(Ⅴ)) and chromate (Cr(Ⅵ)) simultaneously. Herein, ordered mesoporous carbon (OMC) was fabricated with averaged pore diameter of 6.5 nm and surface area of 997 m² g^-1. Zerovalent iron (ZVI) impregnation reduced surface area of ZVI/OMC (432 m² g^-1) and increased I_D/I_G ratio by 13%. Maximal Cr(Ⅵ) and As(Ⅴ) sorption capacities at pH 3 were 0.66 and 0.019 mmol g^-1 by OMC, and 0.71 and 0.39 mmol g^-1 by ZVI/OMC, respectively. Reduction accounted for over 55% for Cr(Ⅵ) and As(Ⅴ) removal followed by complexation and precipitation. Better ZVI/OMC performance was ascribed to higher electron transfer rate and lower electrical resistance than OMC as per electrochemical analysis. Upon Cr(Ⅵ) introduction, As(Ⅴ) removal increased to 0.28 mmol g^-1 by OMC, but decreased to 0.16 mmol g^-1 by ZVI/OMC. OMC could preferably reduce CrO₄^2- to Cr³⁺ by hydroxyl group, which enhanced its zeta potential facilitating As(Ⅴ) sorption. Regarding ZVI/OMC, Fe⁰ and Fe oxide in ZVI/OMC exhibited better affinity to As(Ⅴ), but the competition for the similar active sites resulted in compromised As(Ⅴ) and Cr(Ⅵ) removal. Thus, the novel OMC is advantageous for removal of binary As(Ⅴ) and Cr(Ⅵ), but ZVI/OMC is robust to detoxify single heavy metal.

Keywords: Cr(Ⅵ) and As(Ⅴ); Electron transfer; Ordered mesoporous carbon; Zerovalent iron.

Publication types

Research Support, Non-U.S. Gov't