Use of molybdenum disulfide nanosheets embellished nanoiron for effective capture of chromium (VI) ions from aqueous solution

A novel nanocomposite, i.e., molybdenum disulfide nanosheets embellished nanoiron (MoS2/NZVI), was synthesized by a modified NaBH4 reduction procedure, and used for the effective capture of Cr(VI) in water. The characteristic analysis implied that MoS2 could hinder the aggregation of NZVI. The batch experiments showed that Cr(VI) capture by NZVI/MoS2 (91.7%) was obviously higher than that of either bare NZVI (62.6%) or MoS2 (27.05%). The kinetics of Cr(VI) capture can be well described by the pseudo-second-order model. The effects of pH and natural organic matters were also evaluated. Solution pH was found to be significant to Cr(VI) capture, acidic environment (pH 5.0 and 6.0) was more suitable for Cr(VI) capture. However, natural organic matters demonstrated negative effects on Cr(VI) capture. The capture capacity of NZVI/MoS2 nanocomposite decreased from 126.42 mg/g to 118.48 and 121.07 mg/g when humic acid and fumic acid were present in the solution. X-ray photoelectron spectroscopy analysis of the mechanism indicated that adsorption, reduction, and precipitation were involved in the capture process. The results suggested that the NZVI/MoS2 nanocomposite may be a potential candidate for the capture of Cr(VI) from wastewater.