Cr(VI) Reduction and Sequestration by FeS Nanoparticles Formed in situ as Aquifer Material Coating to Create a Regenerable Reactive Zone

• DOI: 10.1021/acs.est.3c10637
• Publication Date: 2024-04-10T20:12:48Z
• Authors: Zhenhai Liu; Qihong Yang; Panpan Zhu; Yaqi Liu; Xin Tong; Tianchi Cao; Mason B. Tomson; Pedro J. J. Alvarez; Tong Zhang; Wei Chen
• Keywords: Groundwater Remediation; Permeable reactive barrier; Chromate conversion coating

Remediation of large and dilute plumes groundwater contaminated by oxidized pollutants such as chromate is a common difficult challenge. Herein, we show that in situ formation FeS nanoparticles (using dissolved Fe(II), S(-II), natural organic matter nucleating template) results uniform coating aquifer material to create regenerable reactive zone mitigates Cr(VI) migration. Flow-through columns packed with quartz sand are amended first an Fe2+ solution then HS– form nano-FeS on the sand, which does not hinder permeability. This effectively reduces immobilizes Cr(VI), forming Fe(III)–Cr(III) coprecipitates negligible detachment from grains. Preconditioning humic or fulvic acid (used model (NOM)) further enhances sequestration, NOM provides additional binding sites mediates both nucleation growth nanoparticles, verified spectroscopic microscopic evidence. Reactivity can be easily replenished repeating procedures used coating. These findings demonstrate enhancement attenuation capacity effective option mitigate plume migration exposure, particularly when tackling contaminant rebound post source remediation.