Enhanced photo-Fenton assisted photocatalytic degradation of atenolol using a novel rGO embedded double Z-scheme nano-heterojunction: Mechanism, kinetics and toxicity studies

Abstract

In this work, rGO-based ternary dual Z-scheme heterojunction (rGO/CuFe2O4/CdS/Bi2S3 QDs) was formulated for the effective photo-Fenton assisted photocatalytic degradation of a β-blocker, atenolol. The catalyst was synthesised via a simple co-precipitation/hydrothermal method and was characterized using XRD, XPS, FT-IR, SEM, TEM, PL, EIS, ESR, Raman and DRS. It exhibited about 76.5% degradation of atenolol in 360 min under visible light irradiation with a rate constant of 0.004 min−1 wherein the mechanism of enhanced activity was attributed to the formation of OH, h+ and photo-Fenton reaction; a possible mechanism was drafted. The intermediates were determined using GC–MS analysis delineating a plausible degradation pathway, the mineralization of atenolol being confirmed by TOC analysis. The catalyst was reusable and highly stable up to six cycles of degradation, as affirmed via XRD and XPS analysis. Further, the toxicity of the catalyst has been studied using the root cells of Allium cepa, and the degraded product and intermediates were assessed deploying ECOSAR software. Thus, the proposed work has potential which can be implemented in future for the large-scale purification of wastewater.