Enhanced contaminant degradation by FeS under oxic conditions with the coexistence of cobalt and nickel

The process of FeS oxygenation is intrinsically associated with the fate of contaminants in heterogeneous aquifers, whereas the impacts of common heavy metals are poorly understood. In this study, we found that the introduction of Co2+ and Ni2+ (Me2+) resulted in a remarkable 3 to 10-fold enhancement in the degradation of bisphenol A, which stemmed from the significant increase in the generation of •OH and SO4•−. The improved production of reactive species was primarily attributed to the accelerated regeneration of Fe(II); the introduction of Me2+ manipulated the electronic structure of FeS and consequently facilitated electron transfer from S2- to Fe(III), as revealed by experimental evidence and density functional theory calculations. This study represents the first endeavor to underscore the influence of coexisting heavy metals on contaminant degradation during FeS oxygenation.