Highly efficient removal of Cr(VI) from water based on graphene oxide incorporated flower-like MoS2 nanocomposite prepared in situ hydrothermal synthesis.

An efficient adsorbent for the treatment of Cr(VI) was simply fabricated by combining graphene oxide with MoS2 nanosheets via in situ hydrothermal process with CTAB as the surfactant. The experimental results indicated that the agglomeration of the MoS2 nanosheets are reduced and uniformly grown on the graphene sheet during the in situ hydrothermal process, and the introduction of graphene oxide provided higher specific surface area and abundant oxygenic groups. Based on this, the removal efficiency of Cr(VI) onto MoS2/rGO was 75.9% at pH 2.0, which was higher than that of bulk MoS2 (61.0%). On account of Sips adsorption isotherm model, the highest uptake capacity of MoS2/rGO toward Cr(VI) reached 80.8 mg g-1. The adsorption kinetic consequences showed that the chemisorption process was the control step, and the removal mechanism for Cr(VI) is redox and adsorption; in this way, the adsorbed Cr(VI) was partially reduced to Cr(III). Furthermore, this as-prepared adsorbent also presented satisfying reusability for removal of Cr(VI) and can be used for the selective removal of Cr(VI) in the presence of NO3-. In short, it may provide a potential route to enhance the adsorption property of MoS2 toward heavy metals through incorporating with GO, which would expand the applications of MoS2 in the field of treatment of the heavy metal wastewater.