Yang, Danxing and Fang, Wen and Zhang, Hao and Sun, Haitao and Gu, Xueyuan and Chen, Haiyi and Luo, Jun (2024) Effects of nZVI on the migration and availability of Cr(VI) in soils under simulated acid rain leaching conditions. Journal of Hazardous Materials, 476: 134985. ISSN 0304-3894
Full text not available from this repository.Abstract
Hexavalent chromium, Cr(VI), is a ubiquitous toxic metal that can be reduced to Cr(III) by nano-zero-valent iron (nZVI). Finding out effects of continuous rainfall leaching on the Cr(VI) release and availability remains a problem, needing to be addressed. Whether the Cr(VI) reduction by nZVI and continuous rainfall leaching lead to localized heterogeneity in soil is unclear. Therefore, two in situ high-resolution (HR) techniques of the diffusive gradients in thin-films (DGT) and planar optode were combined with ex situ sampling experiments here. Results demonstrate that nZVI decreased Cr(VI) leaching by 5.60–8.50 % compared to control soils. DGT-measured concentrations of Cr(VI), C DGT-Cr(VI), ranged from 7.31 to 19.4 μg L-1 in the control soils, increasing with depth while C DGT-Cr(VI) in nZVI-treated soils (2.41–6.18 μg L-1) decreased or remained stable with depth. However, simulated acid-rain leaching increases C DGT-Cr(VI) by 1.61-fold in nZVI-treated soils, negatively affecting the remediation. DGT measurements in bulk soils using disc devices are better at capturing the change of Cr(VI) availability at different conditions, whereas 2D-HR DGT mappings did not characterize significant mobilization of Cr(VI) at the micro-scale. These findings emphasize the importance of monitoring Cr(VI) release and availability in remediated soil under acid-rain leaching conditions for effective environment management.