Tuning the antimicrobial and photocatalytic activity of nano-ZnO by metal doping

Abstract

The uncontrolled discharge of hospital and pharmaceutical waste pollutes aquatic ecosystems by introducing diverse microorganisms and drug-resistant pathogens that later affect human health, while the release of toxic dyes from textile industries further harms the ecosystem. Nanomaterials, with their multifunctional properties, provide effective solutions for degrading dyes and eliminating harmful microorganisms. In this work, an inexpensive and simple chemical precipitation method was adopted to prepare pure ZnO and Zn1-xMxO nanoparticles doped with metals where M = Ag, Cu, Co, Fe, and Ca, with x set at 0.5. The produced materials were evaluated using a variety of techniques, including XRD, TEM, SEM, and DLS. The results showed that the particle sizes ranged from 92 to 129 nm for all samples, with hydrodynamic diameters of 293 nm for PZO and 383 nm for AgZO. FTIR analysis was used to confirm the formation of Zn-O bonds and assess the purity of the samples. AgZO exhibited significant antibacterial activity among all samples, targeting Gram-positive strains such as B. cereus, L. monocytogenes, and S. aureus, along with Gram-negative E. coli, producing inhibition zones of 10.2±0.35 mm, 11.2±0.29 mm, 10.2±0.29 mm, and 20.8±0.80 mm, respectively. The photocatalytic efficiency in degrading 10 ppm Congo Red (CR) dye reached approximately 95.17%, 94.81%, and 94.81% for CuZO, AgZO, and PZO samples, respectively. The nearly identical band gap energy indicates that the photocatalytic activity of PZO and AgZO NPs is comparable.