Sonochemical assisted preparation of ZnS–ZnO/MCM-41 based on blast furnace slag and electric arc furnace dust for Cr (VI) photoreduction

Iron/steel making industry is a weed that produces large quantities of slag and dust. The objective of the present study was to develop a procedure for obtaining and characterizing photocatalysts derived from this waste for chromium remediation. The MCM-41 was synthesized via sodium silicate (Na2SiO3) derived from Blast Furnace Slag (BFS), and ZnO and ZnS were synthesized based on zinc extracted from Electric Arc Furnace Dust (EAFD). Subsequently, ZnO/ZnS were sono-chemically loaded on the MCM-41 and were tested for the Cr (IV) photoreduction. The resultant ZnO, ZnS, MCM-41, and composites were characterized by X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), N2adsorption–desorption isotherms, Fourier-transform infrared (FT-IR) spectrometry, Dynamic Light scattering, and Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). A regular hexagonal structure of typical mesoporous MCM-41 had been proven by small-angle XRD, HRTEM, and N2 adsorption–desorption. The photoreduction activity of ZnS–ZnO/MCM-41 nanocomposite has obvious efficiency compared to ZnO and ZnO/MCM-41, achieving a 94% photoreduction of Cr (VI) in 180 min under UV irradiation. The slight activity loss after 4 cycles (84.7%) reveals the good photoreduction properties of catalysts. Based on these results, ZnS–ZnO/MCM-41 composite material seems to be high efficiency, green, stable, environment, and economical alternative to be used as a photocatalyst for the reduction of Cr (VI).