Tailored pc@zro₂@cellulose fiber composites as versatile materials for photocatalytic metal ion reduction and microbial deactivation

Water scarcity and contamination pose significant challenges to public health globally. Addressing these issues requires innovative and sustainable water purification technologies. This study investigates novel fixed bed photocatalysts composed of ZrO₂@cellulose fibers, combined with various photocatalytic materials (PCs), including ZnO, V₂O₅, Bi₂S₃, MoS₂, and PANI, for the reduction of heavy metal ions and microbial deactivation in water. The composite materials were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N₂ adsorption/desorption isotherms, and diffuse reflectance spectroscopy (DRS). The results revealed successful integration of the PCs with the ZrO₂-cellulose matrix, facilitating efficient charge transfer and enhanced photocatalytic performance. The photocatalytic activity was evaluated through the reduction of Cr (VI) and Cu (II) ions in simulated wastewater under simulated sunlight irradiation. ZnO-4%@ZrO₂@cellulose and Bi₂S₃-4%@ZrO₂@cellulose demonstrated excellent performance, achieving high reduction rates of Cr (VI) and Cu (III) ions. Kinetic studies showed that the Cr (VI) and Cu (III) ions reduction followed first-order kinetics. The reduction rates were significantly higher for the ZnO, Bi₂S₃, MoS₂, and PANI composites compared to the ZrO₂-cellulose control. Proposed mechanisms elucidate the role of reactive oxygen species in damaging microbial structures. Overall, the results suggest that the developed fixed bed photocatalysts hold promise for efficient water purification.