The contamination of water bodies with organic pollutants has emerged as one of the most pressing environmental and public health challenges of the modern era. The continuous discharge of dyes, pesticides, agricultural runoff, and pharmaceutical residues into the aquatic ecosystem degrades water quality. Long-term exposure to these organic pollutants poses a severe risk to human and aquatic life. ZnO and TiO₂ have emerged as promising photocatalysts, particularly for degrading organic waste in wastewater. However, their photocatalytic activity is limited to the UV region due to their wide band gaps. To improve nanoparticle efficiency, polydopamine (PDA) is incorporated as a modifying agent. PDA-modified ZnO and TiO₂ nanocomposites exhibit enhanced photocatalytic activity in the degradation of various organic pollutants under visible light, compared with their unmodified counterparts. Furthermore, they exhibit improved antibacterial activity against a variety of waterborne pathogens; this is advantageous as wastewater contains both chemical pollutants and microorganisms. Thus, the combined photocatalytic and antibacterial properties of PDA-modified ZnO and TiO₂ make them promising materials for next-generation wastewater treatment.

This study investigated the influence of zinc oxide (ZnO), titanium dioxide (TiO₂), and calcium carbonate (CaCO₃) on the material properties of PLA processed by melt compounding in a twin-screw extruder. The results demonstrated that the incorporation of ZnO and CaCO₃ reduced the thermal stability of PLA. Furthermore, ZnO reduced the complex viscosity and tensile strength of PLA. In contrast, the addition of TiO₂ maintained the thermal stability, complex viscosity, and mechanical properties of PLA. Moreover, it was observed that combining ZnO with TiO₂ and CaCO₃ preserved the mechanical properties of PLA. The findings underscore the significance of hybridization, as it enhanced the properties of PLA/ZnO nanocomposites. Among all the developed composites, ZnO/TiO₂ demonstrated better performance, which could be attributed to the finer dispersion of the fillers observed by scanning electron microscopy. Overall, the findings demonstrate the potential of maintaining the properties of PLA in PLA/ZnO composites through the hybridization of inorganic fillers, particularly when prepared using melt processing.