Synthesis of Fe3O4/ZrO2/ZnO nanoparticle for enhancing visible light photocatalytic and antibacterial activity

Nitroaromatic (especially nitrophenols) compounds, dyes, drugs, pesticides, and photographic chemicals are widely used in industries. Para-nitrophenol (4-NP) is one of the nitroaromatic compounds that was found in wastewater from pharmaceutical and other industrial sources. Also, the presence of microbial contamination in water leads to irreversible damage to human health. Thus, the treatment of bacteria and the effective elimination of 4-NP are both significant issues to human health. The preparation of easily recyclable photocatalytic compounds with high-performance activity for degradation of the hazardous aromatic compounds and antimicrobial activity (Gram-negative and Gram-positive bacteria) are highly desirable for different practical applications. In this study, a novel magnetic photocatalyst, Fe3O4/ZrO2/ZnO nanoparticle (NP), was synthesized via an inexpensive protocol at mild conditions. The surface morphology and chemical composition of Fe3O4/ZrO2/ZnO NP were studied by FE-SEM, TEM, EDS, VSM, XRD, UV-DRS, PL, XPS and ICP. Fe3O4/ZrO2/ZnO NP exhibited high activity in photocatalytic degrading para-nitrophenol (4-NP) of about 90 % after 38 min under solar light irradiation. The antibacterial activity of Fe3O4/ZrO2/ZnO NP against E. coli, and S. aureus was evaluated by calculation of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). MIC and MBC values for E. coli were determined to be 0.125 and 1.25 (µg/mL), respectively. Also, these amounts for S. aureus were evaluated and equal to 1.25 and 12.5 (µg/mL), respectively. The reusability of the nanoparticle was shown by the high performance of the photocatalyst in the degradation of 4-NP after five runs (>80 %). Also, the Fe3O4/ZrO2/ZnO NP demonstrated high antibacterial activity in the low dosage of the nanoparticle. Therefore, the ZrO2/ZnO NP supported by Fe3O4 perform well in antibacterial activity and degradation of 4-NP.