Reduced Graphene Oxide-Zinc Sulfide Nanocomposite Decorated with Silver Nanoparticles for Wastewater Treatment by Adsorption, Photocatalysis and Antimicrobial Action

Abstract

Reduced graphene oxide nanosheets decorated with ZnS and ZnS-Ag nanoparticles are successfully prepared via a facile one-step chemical approach consisting of reducing the metal precursors on a rGO surface. Prepared rGO-ZnS nanocomposite is employed as an adsorbent material against two model dyes: malachite green (MG) and ethyl violet (EV). The adsorptive behavior of the nanocomposite was tuned by monitoring some parameters, such as the time of contact between the dye and the adsorbent, and the adsorbent dose. Experimental data were also simulated with kinetic models to evaluate the adsorption behavior, and the results confirmed that the adsorption of both dyes followed a pseudo 2nd order kinetic mode. Moreover, the adsorbent was also regenerated in a suitable media for both dyes (HCl for MG and ethanol for EV), without any significant loss in removal efficiency. Ag doped rGO-ZnS nanocomposite was also utilized as a photocatalyst for the degradation of the selected organic contaminant, resorcinol. The complete degradation of the phenolic compound was achieved after 60 min with 200 mg of rGO-ZnS-Ag nanocomposite under natural sunlight irradiation. The photocatalytic activity was studied considering some parameters, such as the initial phenol concentration, the photocatalyst loading, and the pH of the solution. The degradation kinetics of resorcinol was carefully studied and found to follow a linear Langmuir–Hinshelwood model. An additional advantage of rGO-ZnS and rGO-ZnS-Ag nanocomposites was antibacterial activity against Gram-negative bacterium, E. coli, and the results confirmed the significant performance of the nanocomposites in destroying harmful pathogens.

Water chemical treatment by photocatalytic activity of reduced graphene oxide-decorated zinc sulfide nanocomposite

“…Thus, the prepared catalyst tends to lose its activity, and the efficiency of the degradation process decreases. Similar results was also observed by Naeem et al [48].…”

Synthesis of iron oxide nanoparticles encapsulated poly(styrene‐co‐4‐vinyl pyridine) nanocomposites for column adsorption and photocatalytic degradation of para nitrophenol from water

“…Accordingly, based on Equation (18a), from the Figure 9A, the photo‐degradation % or efficiency is observed to be around 52% after 30 min, 94.5% after 60 min and almost complete degradation (>98%) after 70 min. Because of low concentration of PNP, the degradation kinetics show a good fitting to the 1st order Langmuir–Hinshelwood (Equation (18b)) 45 with a rate constant k of 0.029 min −1 . In contrast, there is no measurable photocatalytic degradation of the PNP solution of same concentration under similar condition with the unfilled CP polymer containing 0% ION as observed in Figure 9B which indicates that the IONs present in the polymer is responsible for the photocatalytic degradation of PNP.…”

Hydrophilicity and Pore Structure Enhancement in Polyurethane/Silk Protein–Bismuth Halide Oxide Composite Films for Photocatalytic Degradation of Dye

“…Consequently, during the film-forming process, the presence of SF promotes phase separation between SF and PU, ultimately leading to the formation of larger, more porous structures with improved connectivity. This not only increases the loading capacity for active species but also enhances the diffusion rate of pollutants in the aqueous phase within the film and improves contact efficiency with photocatalysts [ 25 , 26 ]. When various types of BiOX (X=Cl, Br, I) are incorporated into the film, the internal cavities of the film become filled, resulting in the formation of nanosheet-like structures of varying sizes on the surface of SF, as shown in Figure 3 (c 2 ,c 3 ,d 2 ,d 3 ,e 2 ,e 3 ).…”