Magnetically Separable MoS2/Fe3O4/nZVI Nanocomposites for the Treatment of Wastewater Containing Cr(VI) and 4-Chlorophenol

Abstract

With a large specific surface area, high reactivity, and excellent adsorption properties, nano zerovalent iron (nZVI) can degrade a wide variety of contaminants in wastewater. However, aggregation, oxidation, and separation issues greatly impede its wide application. In this study, MoS2/Fe3O4/nZVI nanocomposites were successfully synthesized by a facile step-by-step approach to overcome these problems. MoS2 nanosheets (MNs) acted as an efficient support for nZVI and enriched the organic pollutants nearby, leading to an enhanced removal efficiency. Fe3O4 nanoparticles (NPs) could not only suppress the agglomeration and restacking of MNs, but also facilitate easy separation and recovery of the nanocomposites. The synergistic effect between MNs and Fe3O4 NPs effectively enhanced the reactivity and efficiency of nZVI. In the system, Cr(VI) was reduced to Cr(III) by nZVI in the nanocomposites, and Fe2+ produced in the process was combined with H2O2 to further remove 4-Chlorophenol (4-CP) through a Fenton reaction. Furthermore, the nanocomposites could be easily separated from wastewater by a magnet and be reused for at least five consecutive runs, revealing good reusability. The results demonstrate that the novel nanocomposites are highly efficient and promising for the simultaneous removal of Cr(VI) and 4-CP in wastewater.

Molybdenum‐based heterogeneous catalysts for the control of environmental pollutants

“…Traditional adsorption method for the treatment of heavy metal ions is usually achieved by activated carbon and graphene materials 129 . Although the adsorption surface area of them is large, the adsorption of heavy metal ions is not selective due to the existence of competitive adsorption 130 …”

Spherical Bi2WO6/Bi2S3/MoS2 n-p Heterojunction with Excellent Visible-Light Photocatalytic Reduction Cr(VI) Activity

“…Water-soluble, non-biodegradable hexavalent chromium Cr(VI), which easily penetrates through food chain enrichment, can induce cellular oxidative stress, leading to DNA damage, gene mutation, fetal malformation, and carcinogenesis, is one of the most dangerous heavy metals [ 4 , 5 ]. Cr(VI) is widely applied in smelting, electroplating, painting, chemical manufacturing, and tanned leather [ 6 , 7 , 8 ]. The World Health Organization stipulates that the maximum limit of pollutants in surface water is 0.1 mg L −1 .…”

Application of N‐Doped MoS2 Nanocrystals for Removal of Azo Dyes in Wastewater

“…To examine the controlling mechanisms of the adsorption process, pseudo-first-order and pseudo-secondorder models were used to fit the experimental data, expressed by Eqs. (3) and (4), respectively [22]. They were tested for the adsorption of MO on NDMN in this study.…”