Sunlight assisted highly efficient photocatalytic remediation of organic pollutants by green biosynthesized ZnO@WO3 nanocomposite

Abstract

The widespread use of toxic plastic additives in the plastics industry and dyes in various sectors has drawn scientific attention since their ability to leak from consumer goods raises environmental concerns. Plastic additives and dyes also have endocrine disruptor, genotoxic, and persistent properties that have been demonstrated. Herein, photodegradation of bisphenol A (BPA) and Auramine O (AO) in water was investigated. Herin, the structural design of ZnO doped WO3 nanocomposite has been synthesized via facile precipitation and green synthesis methodology. Sharp PXRD peaks ensured that the spherical nanocomposite had great crystallinity and purity. XPS analysis, PXRD, and FE-SEM confirmed the effective doping of ZnO with WO3. Subsequently, ZnO@WO3 nanocatalyst was evaluated for the effective elimination of BPA and AO at variable reaction parameters (pollutant: 5–25 mgL−1; catalyst: 5–25 mg; pH: 5–9, dark-sunlight-artificial bulb). At neutral pH and in sunlight, ZnO@WO3 demonstrated maximal degradation of 5 mgL−1 of BPA (91%) and AO (96%) at a catalytic dosage of 15 mg. The yellow color of AO decolorized within 3 h, confirming the effective removal of AO. First-order kinetics followed by initial Langmuir adsorption constituted the degradation process. The presence of different radical quenchers (t-BuOH, p-BZQ, Na2EDTA) concluded that hydroxyl radical plays a significant role in the degradation of toxic BPA and AO—formation of safer metabolites after degradation of BPA and AO confirmed by LC-MS analysis. The efficiency of green fabricated ZnO@WO3 was also investigated in actual wastewater samples to remove BPA and AO. Nanocomposite demonstrated remarkable sustainability and cost-effectiveness by remaining effective for up to eight cycles without experiencing any appreciable activity reduction. A potential and different photocatalyst for industrial applications, green synthesized ZnO@WO3 nanocomposite has good surface properties.