RESUMO
Wastewater treatment is becoming increasingly important due to the potential shortage of pure drinking water in many parts of the world. Adsorption offers a potential technique for the uptake of contaminants and wastewater purification. In the last two decades, several efforts have been made to remove fast green (FG) dye from wastewater via different adsorbent materials. However, adsorption capacity shown by these adsorbents is low and time-consuming. Herein, we have synthesized for the first time a new powdered adsorbent ZnOS+C, modified zinc peroxide with sulfur and activated carbon to effectively remove FG dye from wastewater. Results of batch adsorption experiments have suggested that ZnOS+C has the maximum adsorption potential of 238.28 mg/g for FG dye within 120 min of adsorption equilibrium for a wide range of pH ranging from 2 to 10 pH. The adsorption process conforms to the Freundlich isotherm model, suggesting a multilayered adsorption process on the outer surface of ZnOS+C. The adsorption kinetics study indicates that the kinetics of the reaction are the intraparticle diffusion model. Briefly, this study shows proof of the application of ZnOS+C powder as a new eco-friendly adsorbent with extremely high efficiency and high surface area for removing FG dye.
RESUMO
An exemplary vision to understand the fundamental role of metal-doped multi-components system such as Au/Ag doped CZTS (Cu2ZnSnS4) nanocrystals encourages the non-vacuum approach for the best performing photocatalyst. Hydrophilic nanoparticles (Au/Ag and CZTS) are allowed to amalgamate under NTP atmosphere, eradicating the prerequisite for high-end equipment. The potential of Au and Ag-doped CZTS nanoparticles was speculated using various optical and structural characterizations. The absorption range of CZTS nanoparticles lies in the visible range, while Au/Ag doping slightly red-shifts the absorption range, considered the desirable state for photocatalysis. The synthesized nanoparticles are highly monodispersed with â¼15-35 nm particle size for Ag, Au, and CZTS. Photocatalysis is a discernible scheme for treating wastewater containing dyes, textile effluents, chemicals, and heavy metals. Here, we strive to use these ex-situ synthesized nanomaterials as photocatalysts, where the real textile waste (collected from industrial outlets), dyes, and heavy metal (chromium (VI)) have been photo-reduced after scrutinizing the finest combination of Ag or Au doped CZTS. Au-CZTS shows superior catalytic activity with an efficiency of 99.7% with a rate constant of 0.2 min-1 (while Ag-CZTS shows 90% efficiency with a rate constant of 0.07 min-1); hence, used for real textile waste and heavy metal (Chromium VI) photo-reduction. The maximum efficiency achieved for textile-1, textile-2, and Cr (VI) reductions is 80%, 70%, and 97%, respectively. The nanocrystals are highly stable and recyclable, tested for 15 repeated cycles. These studies pave the way for developing cost-effective, environmentally-friendly, durable, and selective semiconductor-metal (Au/Ag) hybrid heterostructures as visible-light-driven photocatalysts for wastewater remediation.
