SnO2 and CuO anchored on zeolite as an efficient heterojunction photocatalyst for sunlight-assisted degradation of cefixime

The fabrication of heterojunction nanocomposites has been proven as a highly efficient strategy to achieve promising photocatalysts. In this study, tin oxide (SnO2) and copper oxide (CuO) nanoparticles (NPs) were synthesized in situ using Rosmarinus officinalis and simultaneously anchored on zeolite for the fabrication of zeolite/SnO2/CuO as a novel heterojunction photocatalyst. The performance of zeolite/SnO2/CuO was assessed against photodegradation of cefixime as a model pharmaceutical contaminant. A good catalytic potential and synergistic effect was obtained for zeolite/SnO2/ CuO compared to pure SnO2 and CuO NPs. Under optimum conditions, 89.65% of cefixime was degraded after 2.5 h under natural sunlight. Based on radical quenching experiments, the importance of involved oxidizing species in the photodegradation of cefixime using zeolite/SnO2/CuO was in order of h(+) > (OH)-O-center dot > O-2(center dot-). Among studied anions, the highest inhibitory effect was observed for nitrate ion. Also, the main intermediates of the photodegradation process of cefixime in zeolite/SnO2/CuO system were determined by HPLC-MS and the possible pathways were suggested. More than 83% cefixime was removed after three catalyst reuse cycles, indicating a cost-effectiveness potential in the reusability of zeolite/ SnO2/CuO. Also, the toxicity and plant growth tests revealed the feasibility of discharging the treated cefixime solutions to irrigate agricultural crops. Overall, the obtained results provide a promising technique with a synergistic feature for the efficient removal of organic pollutants.

Automated summary

The fabrication of heterojunction nanocomposites using Rosmarinus officinalis as a catalyst has led to the successful synthesis of zeolite/SnO2/CuO, a novel photocatalyst with enhanced performance for the photodegradation of cefixime. The study demonstrates the importance of involved oxidizing species and identifies the inhibitory effect of nitrate ion in the degradation process. Furthermore, the research shows the potential for the reuse of zeolite/SnO2/CuO and the feasibility of discharging the treated cefixime solutions for agricultural irrigation.