Interfacial coupling effects of chitosan integrated ZrO2/Bi2O3/CeO2 quaternary composite for efficient wastewater treatment and antimicrobial activity

There is an urgent need for efficient and sustainable solutions to tackle the escalating issues of wastewater pollution and microbial resistance. To this end, a novel quaternary chitosan-incorporated CeO₂/ZrO₂/Bi₂O₃ (CS-TMO) composite was made using a co-precipitation approach and assessed for its dual functionalities in wastewater treatment and antibacterial efficacy. The structural and chemical properties of the composite were analyzed using XRD, XPS, SEM, and BET studies which revealed that CS-TMO exhibited nanoflake morphology with surface area of 27.77 m²/g, and a pore volume of 0.003 cc/g. The composite photocatalytically degraded 95% of malachite green (MG) in 180 min and 92% of Acid Blue 113 (AB 113) in 240 min when illuminated with solar light. The degradation process was greatly improved under ideal conditions, which included a catalyst dosage of 9 mg, a pH of 7 for MG and 9 for AB113, and the presence of electrolytes based on carbonates. Complete mineralization into CO₂ and H₂O was confirmed using ESI–MS analysis, which explained the breakdown mechanisms. Three cycles of reusability testing revealed that the material maintained its integrity with no loss of efficiency. Additionally, antimicrobial experiments showed that it effectively killed Escherichia coli bacteria and Aspergillus niger and Candida albicans fungi. These results highlight the possibility of CS-TMO composites as environmentally friendly materials for controlling microbes and restoring wastewater.