A novel cellulose hydrogel coating with nanoscale Fe0 for Cr(VI) adsorption and reduction

Yin Wang; Lan Yu; Ruotong Wang; Yun Wang; Xiaodong Zhang

doi:10.1016/j.scitotenv.2020.138625

A novel cellulose hydrogel coating with nanoscale Fe⁰ for Cr(VI) adsorption and reduction

Sci Total Environ. 2020 Jul 15:726:138625. doi: 10.1016/j.scitotenv.2020.138625. Epub 2020 Apr 13.

Authors

Yin Wang¹, Lan Yu¹, Ruotong Wang¹, Yun Wang¹, Xiaodong Zhang²

Affiliations

¹ School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
² School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address: zhangxiaodong@usst.edu.cn.

PMID: 32315860
DOI: 10.1016/j.scitotenv.2020.138625

Abstract

A novel cellulose hydrogel coating nanoscale Fe⁰ (CH@nFe⁰) was synthesized and utilized to improve the dispersibility and oxidation resistance of nFe⁰. The composition and structure of CH@nFe⁰ were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) before and after its reaction with Cr(VI). The performance of CH@nFe⁰ in the removal of Cr(VI) was evaluated through a comparative experiment between nFe⁰ and CH. The influence of the initial concentration of Cr(VI), temperature, dosage, and the initial pH of the solution were also evaluated in this reaction system. The results showed that CH@nFe⁰ allowed a higher Cr(VI) removal rate compared to nFe⁰ and CH. This might have derived from an enhanced reduction and adsorption of Cr(VI) by CH. Meanwhile, the network structure of the cellulose hydrogel served as a mass-transfer channel between Cr(VI) and nFe⁰. In addition, the increase of the initial solution pH minimized the removal of Cr(VI). This mechanism revealed that CH coating resulted in an enhancement of the adsorption capability and reducibility of CH@nFe⁰ with respect to Cr(VI). The CH@nFe⁰ composite is characterized by an advantageous mesoporous network structure and functional groups of amide and carboxylic acid, which provide additional active sites and promote mass transfer. This new three-dimensional (3-D) cellulose hydrogel coating containing nFe⁰ can be effectively used for the removal of Cr(VI) ions from aquatic environments.

Keywords: Adsorption and reduction.; Cellulose hydrogel.; Cr(VI).; Nanoscale nFe(0).