Mechanistic insights into manganese oxide impacting the oxidation and transport of Cr(III) immobilized by nano-zero valent charged ion particles in water-saturated porous media.
J Hazard Mater
; 469: 134050, 2024 May 05.
Article
em En
| MEDLINE
| ID: mdl-38493629
ABSTRACT
The presence of manganese oxide (MnO2) could influence the stability of green-synthesized nano-zero valent iron (nZVI@GT) associated with trivalent chromium (Cr(III)) after its excess application in the in situ remediation of hexachromium (Cr(VI)) contaminated soil. The research findings revealed that the co-transport of the remaining nZVI@GT with Cr(III) was substantially inhibited by high δ-MnO2 concentrations due to the formation of hetero-aggregates between nZVI@GT and δ-MnO2, resulting in an increased irreversible attachment parameter at second-site in a two-site kinetic attachment model. Simultaneously, the Cr(III) complex immobilized on nZVI@GT could be oxidized leading to high levels of Cr(VI) leaching at high δ-MnO2 concentrations. During this process, Mn(IV) was converted to Mn(III)/Mn(II). Subsequently, leachate containing a partial amount of Cr(VI) preferentially adsorbed onto the nZVI@GT surface, enhancing the dispersion of the nZVI@GT and δ-MnO2 agglomerates. Thereafter, nZVI@GT transportability was enhanced with a decreased second-site attachment parameter and the flow content of dissolved Cr(VI) was increased to double, also increasing the potential risk of Cr(VI) being carried by nZVI@GT to underground water systems. This study provides theoretical support for preserving the long-term stability of nZVI@GT after the in situ remediation of heavy metal-contaminated sites in the presence of δ-MnO2.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Hazard Mater
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China
País de publicação:
Holanda