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Review on stabilization/solidification methods and mechanism of heavy metals based on OPC-based binders.

Authors :
Chen L
Nakamura K
Hama T
Source :
Journal of environmental management [J Environ Manage] 2023 Apr 15; Vol. 332, pp. 117362. Date of Electronic Publication: 2023 Jan 28.
Publication Year :
2023

Abstract

Stabilization/solidification (S/S) with ordinary portland cement (OPC)-based binders is a suitable method to remediate heavy metal (HM)-contaminated soil and reuse resources of industrial wastes. In industrial wastes, alkaline wastes such as red mud (RM), soda residue (SR), pulverized fly ash (PFA), and alkalinity granulated blast furnace slag (GGBS) can immobilize HM ions (Pb <superscript>2+</superscript> , Zn <superscript>2+</superscript> , Cd <superscript>2+</superscript> , Cr <superscript>3+</superscript> , and Cu <superscript>2+</superscript> ) by precipitation. However, some HM ions (such as AsO <subscript>4</subscript> <superscript>3-</superscript> ) would redissolve within the strong alkali environment. In this case, PFA, GGBS, metakaolin (MK), and incinerated sewage sludge ash (ISSA) which have low pH, can be used to immobilize HM ions or added to the OPC-based binders to adjust the pH in the soil products. Moreover, the calcium silicate hydrate (CSH), calcium aluminum silicate hydrate (CASH), ettringite (AFt), and calcium monosulfoalumiante hydrates (AFm) generated during the pozzolanic reaction can also immobilize HM ions by adsorption on the surface, ion exchange, and encapsulation. SR and GGBS can be used to immobilize the HMs (such as CrO <subscript>4</subscript> <superscript>2-</superscript> and AsO <subscript>4</subscript> <superscript>3-</superscript> ), which are mainly affected by AFt and AFm. For those not affected by AFt and AFm but related to immobilization by precipitating (such as Mn <superscript>2+</superscript> ), other wastes except SR and GGBS are suitable for treating contaminated soil. Nevertheless, the formation of AFt is also instrumental for soil product strength. There are several factors affecting soil product strength. In the future, the influence of different hydration products on the S/S effects, competitive adsorption of HM ions, effects on long-term HM stabilization, and novel materials are worth being explored by researchers.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1095-8630
Volume :
332
Database :
MEDLINE
Journal :
Journal of environmental management
Publication Type :
Academic Journal
Accession number :
36716545
Full Text :
https://doi.org/10.1016/j.jenvman.2023.117362