Decorating nanoscale FeS onto metal-organic framework for the decontamination performance and mechanism of Cr(VI) and Se(IV)

Elevated concentrations of toxic Cr(VI) and Se(IV) have been increasingly found in the natural water environment, which imposed potential harmful to human health. In this study, nanoscale FeS was decorated onto metalorganic framework (FeS/MOFs) for the effective decontamination of Cr(VI) and Se(IV) in wastewater. X-ray photoelectron spectroscopy (XPS) was employed to reveal the decontamination mechanism of Se(IV) and Cr(VI) with FeS/MOFs. The results indicated that FeS/MOFs showed an effective decontamination performance for Cr (VI) and Se(IV) via an adsorption process. The pseudo-second order kinetics model fitted the kinetic adsorption of Cr(VI) and Se(IV) on FeS/MOFs best, exhibiting chemical interaction mainly contributed to Cr(VI) adsorption on FeS/MOFs. The adsorption of Cr(VI) and Se(IV) was affected by medium pH, adsorption dosage, and temperature. The isotherm of Cr(VI) and Se(IV) adsorption on FeS/MOFs was best described with the Langmuir mode. XPS analysis revealed that both surface adsorption and reduction are responsible for decontamination of Cr(VI) and Se(IV) using FeS/MOFs. The present study suggested the promise of FeS/MOFs nanocomposite as a low-cost, and "green" adsorbent for the effective decontamination of Cr(VI) and Se(IV) from water effluents.