DEVELOPMENT AND EVALUATION OF PHOTOCATALYTIC AND ANTIMICROBIAL NANOPARTICLES FOR ENHANCED REMOVAL OF PATHOGENS AND ORGANIC POLLUTANTS IN ADVANCED WATER TREATMENT SYSTEMS

Abstract

Access to safe and clean water remains a critical global challenge due to the increasing presence of organic pollutants and pathogenic microorganisms in water sources. Conventional treatment methods often fail to completely remove these contaminants, necessitating the development of innovative, efficient, and sustainable solutions. This study focuses on the development and evaluation of multifunctional nanoparticles combining photocatalytic and antimicrobial properties for enhanced water treatment. Titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles were synthesized via sol–gel methods, while metallic nanoparticles such as silver (Ag) were prepared through chemical reduction and integrated with metal oxides to form stable nanocomposites. Characterization using SEM, TEM, XRD, FTIR, UV–Vis spectroscopy, and BET analysis confirmed favorable morphology, crystallinity, surface functionalization, and extended light absorption in the visible range. Photocatalytic studies demonstrated that composite nanoparticles achieved up to 90% degradation of model organic pollutants such as methylene blue and rhodamine B under UV and visible light, significantly outperforming pure metal oxides. Antimicrobial evaluation against E. coli, S. aureus, and P. aeruginosa showed substantial inhibition and bacterial inactivation through reactive oxygen species generation and membrane disruption. Bench-scale water treatment tests revealed significant reductions in COD, BOD, turbidity, and microbial load, with immobilized nanoparticles retaining high performance over multiple cycles. The synergistic combination of photocatalytic and antimicrobial functions in these nanocomposites presents a promising, sustainable, and energy-efficient strategy for simultaneous chemical and biological water purification.