Nanoscale zero valent iron supported on MgAl-LDH-decorated reduced graphene oxide: Enhanced performance in Cr(VI) removal, mechanism and regeneration

Xiaoshu Lv; Xiaofeng Qin; Kaifeng Wang; Yiyin Peng; Peng Wang; Guangming Jiang

doi:10.1016/j.jhazmat.2019.03.091

Nanoscale zero valent iron supported on MgAl-LDH-decorated reduced graphene oxide: Enhanced performance in Cr(VI) removal, mechanism and regeneration

J Hazard Mater. 2019 Jul 5:373:176-186. doi: 10.1016/j.jhazmat.2019.03.091. Epub 2019 Mar 20.

Authors

Xiaoshu Lv¹, Xiaofeng Qin¹, Kaifeng Wang¹, Yiyin Peng¹, Peng Wang¹, Guangming Jiang²

Affiliations

¹ Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing 400067, China.
² Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing 400067, China. Electronic address: jiangguangming@zju.edu.cn.

PMID: 30921568
DOI: 10.1016/j.jhazmat.2019.03.091

Abstract

The scaled application of nanoscale zero-valent iron nanoparticles (nZVI or Fe° NPs) in environmental remediation is challenged by easy surface passivation and particle aggregation. To improve this situation and enhance their performance in Cr(VI) removal from water phase, we present one novel strategy to hybridize nZVI with layered double hydroxide (LDH) decorated reduced graphene oxide (rGO). The as-prepared ternary (Fe@LDH/rGO) composites possess better dispersibility, improved hydrophilicity and more positive surfaces that allows higher removal efficiency and capacity for Cr(VI) oxyanions. Composition proportion are optimized and influences of surroundings (solution pH, Cr(VI) concentration and temperature) are evaluated. Also, we demonstrate that Fe@LDH/rGO can be reused with suitable post-treatments, which combines alkaline solution desorption and NaBH₄ revivification possess. Cr desorption and Fe leaching ratio during regeneration should be critical indicators that determine the recovery efficiency. Synergistic effect within this ternary system not only contributes to its superiorities in stability, but also continuous iron corrosion via the formation of micro Fe-C batteries, where rGO acts as cathode and alternative electron conductor. The present work suggests great potentials of Fe@LDH/rGO composites in groundwater remediation.

Keywords: Cr(VI) removal; Graphene; Layered double hydroxide; Nanoscale zero-valent iron; Regeneration.

Publication types

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