Constructing the active surface soil layer with ZVI-biochar amendment for simultaneous immobilization of As and Zn in both contaminated soil and groundwater: Continuous versus intermittent infiltration mode

Xiang Chen; Xiaoyun Xu; Yaqiang Wei; Xinbing Wang; Xinde Cao

doi:10.1016/j.jhazmat.2022.130518

Constructing the active surface soil layer with ZVI-biochar amendment for simultaneous immobilization of As and Zn in both contaminated soil and groundwater: Continuous versus intermittent infiltration mode

J Hazard Mater. 2023 Mar 5:445:130518. doi: 10.1016/j.jhazmat.2022.130518. Epub 2022 Nov 29.

Authors

Xiang Chen¹, Xiaoyun Xu², Yaqiang Wei¹, Xinbing Wang³, Xinde Cao⁴

Affiliations

¹ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
² School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: xuxiaoyun@sjtu.edu.cn.
³ Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
⁴ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Engineering Research Center of Solid Waste Treatment and Recycling, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address: xdcao@sjtu.edu.cn.

PMID: 36493652
DOI: 10.1016/j.jhazmat.2022.130518

Abstract

In this study, the zero valent iron-biochar composite (ZVI-BC) was applied to construct an active surface soil layer for the simultaneous remediation of As-Zn contaminated soil and groundwater, focusing on the influence of the infiltration mode of pumped-up groundwater into soil. The active surface soil treated more contaminated groundwater for As (4.45-5.46 L kg^-1 soil) than that for Zn (2.52-3.13 L kg^-1 soil) under both continuous and intermittent infiltration modes, with about 98% As and 95% Zn removed from groundwater and retained in the soil. As(V) precipitated with Fe(III) due to ZVI oxidation, which was responsible for the As immobilization. The soil under the intermittent infiltration mode was enriched by the Sphingomonas with arsenate reductase gene, which promoted more reduction of As(V) into As(III) and facilitated coprecipitation of As(III) with Fe(III). The Mn oxide determined the sorption of Zn in the active soil layer, where the Hyphomicrobium, one type of manganese oxidizing bacteria, was much higher under the continuous infiltration mode, which accounted for the more Zn immobilization. After the remediation, both As and Zn immobilized in the active surface soil showed high stability, with the average downward migration rate of only 0.207-0.368 cm year^-1 within 20-year rainfall exposure. Our findings indicate that this active surface soil layer is applicable for simultaneous immobilization of As and Zn in both contaminated soil and groundwater, and the groundwater intermittent infiltration could be a better option considering the remediation effectiveness, the immobilization mechanism, the long-term stability, and the energetic efficiency.

Keywords: Active soil layer; As and Zn; Groundwater; Immobilization; Soil.

Publication types

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

MeSH terms

Charcoal
Ferric Compounds
Groundwater*
Soil
Soil Pollutants* / analysis
Zinc

Substances

biochar
Soil
Ferric Compounds
Charcoal
Zinc
Soil Pollutants