TY - JOUR

T1 - Preparation of a silicon-iron amendment from acid-extracted copper tailings for remediating multi-metal-contaminated soils

AU - Mu, Jing

AU - Hu, Zhengyi

AU - Huang, Lijuan

AU - Xie, Zijian

AU - Holm, Peter E.

PY - 2020

Y1 - 2020

N2 - Industrial by-products provide materials for remediation measures. In this study, a silicon-iron amendment was prepared from residue originating from acid-extracted copper (Cu) tailings based on thermal activation at temperatures ranging from 550 degrees C to 1150 degrees C for 30 min with the use of additives (CaO, Na2CO3, NaOH). The remediation performance of the amendment was evaluated through soil incubation and greenhouse pot experiments with vetiver (Vetiveria zizanioides). The results showed that the highest levels of soluble Si (6.11% of the total Si) and Fe (2.3% of the total Fe) in the amendment were achieved with thermal activation at 1150 degrees C for 30 min using an optimal ratio between residue and additives (residue: CaO: Na2CO3: NaOH =1: 0.4: 0.4: 0.2). Heavy metal release indicated that the amendment could be safely used for soil remediation. The incubation experiments showed that the DTPA-extractable Cd, Cr and Pb in contaminated soils decreased with increasing amendment rate, which was not observed for As. The amendment-induced decrease in the Cd, Cr and Pb availability in contaminated soils could be explained by pH-change induced immobilization, Fe-induced chemisorption, Si-induced co-precipitation, and Ca-induced ion exchange. Correlation analysis suggested that there were significant negative correlations between DTPA-extractable Cd, Cr and Pb and the pH, Fe, Si, and Ca in soil pore water and soil. The most suitable amendment rate was determined to be 1% by balancing the efficacy and wise utilization of the amendment. The pot experiment demonstrated that the amendment promoted the vetiver growth and stimulated the accumulation of Cd and Cr in the roots. The amendment was proved to be promising for the phytostabilization of Cd, Cr and Pb in contaminated soils. Further investigations are required to determine whether the amendment is a tool for the long-term remediation of multi-metal-contaminated soils at the field scale. (C) 2019 Elsevier Ltd. All rights reserved.

AB - Industrial by-products provide materials for remediation measures. In this study, a silicon-iron amendment was prepared from residue originating from acid-extracted copper (Cu) tailings based on thermal activation at temperatures ranging from 550 degrees C to 1150 degrees C for 30 min with the use of additives (CaO, Na2CO3, NaOH). The remediation performance of the amendment was evaluated through soil incubation and greenhouse pot experiments with vetiver (Vetiveria zizanioides). The results showed that the highest levels of soluble Si (6.11% of the total Si) and Fe (2.3% of the total Fe) in the amendment were achieved with thermal activation at 1150 degrees C for 30 min using an optimal ratio between residue and additives (residue: CaO: Na2CO3: NaOH =1: 0.4: 0.4: 0.2). Heavy metal release indicated that the amendment could be safely used for soil remediation. The incubation experiments showed that the DTPA-extractable Cd, Cr and Pb in contaminated soils decreased with increasing amendment rate, which was not observed for As. The amendment-induced decrease in the Cd, Cr and Pb availability in contaminated soils could be explained by pH-change induced immobilization, Fe-induced chemisorption, Si-induced co-precipitation, and Ca-induced ion exchange. Correlation analysis suggested that there were significant negative correlations between DTPA-extractable Cd, Cr and Pb and the pH, Fe, Si, and Ca in soil pore water and soil. The most suitable amendment rate was determined to be 1% by balancing the efficacy and wise utilization of the amendment. The pot experiment demonstrated that the amendment promoted the vetiver growth and stimulated the accumulation of Cd and Cr in the roots. The amendment was proved to be promising for the phytostabilization of Cd, Cr and Pb in contaminated soils. Further investigations are required to determine whether the amendment is a tool for the long-term remediation of multi-metal-contaminated soils at the field scale. (C) 2019 Elsevier Ltd. All rights reserved.

KW - Silicon-iron amendment

KW - Thermal activation

KW - Multi-metal-contaminated soils

KW - Remediation

KW - HEAVY-METALS

KW - VETIVERIA-ZIZANIOIDES

KW - PB

KW - ZN

KW - CD

KW - PHYTOREMEDIATION

KW - ACCUMULATION

KW - CU

KW - IMMOBILIZATION

KW - AVAILABILITY

U2 - 10.1016/j.envpol.2019.113565

DO - 10.1016/j.envpol.2019.113565

M3 - Journal article

C2 - 31733972

VL - 257

JO - Environmental Pollution

JF - Environmental Pollution

SN - 0269-7491

M1 - 113565

ER -