An integrated hybrid nanoplatform with polymer coating: Zinc based green nanocomposites with improved photoactivity under sunlight irradiation

Abstract

Domestic, farming, and industries required many highly persisting and low-priced pesticides. Environmental concern arose via bioaccumulation and toxicity of pesticides emphasizing for requirement of effective removal techniques based on novel nanomaterials. To substantiate this, the potential of crystalline hybrid nanocomposites of zinc oxide and zinc sulfide with urea-formaldehyde (ZnO@UF and ZnS@UF) were utilized to remove hazardous pesticides. ZnO@UF and ZnS@UF were synthesized via green methodology using Sapindus mukorossi seed extract as natural surfactant. Characterization indicated the successful formation of hybrid nanoparticles (particle size: <100 nm) with polymer coating. Zinc oxide/sulfide-resin (25 mg) proved to be highly efficient in the degradation of chlorpyrifos (89–92%) at optimum pollutant concentration (2 mg L−1) and under neutral pH conditions. The sharp decline in chlorpyrifos concentration followed by slow reduction revealed first-order kinetics initiated with Langmuir adsorption. The highest removal by hybrid nanocomposites showed their superiority attributed to enhanced surface area and narrow band gap of ZnO@UF (78.9 m2g−1; 1.3 eV) and ZnS@UF (63.8 m2g−1; 1.8 eV) as an effect of semiconducting and interactive feature. Moreover, ZnO@UF reduced the half-life of chlorpyrifos up to 3.4 h than ZnS@UF (3.5 h) and bared ZnO (4.9 h) and ZnS (6.1 h). Scavenger analysis by ethanol, benzoquinone, and triethanolamine confirms presence of hydroxyl radicals, holes, and O2.⁻, responsible for degradation of chlorpyrifos. GC-MS analysis revealed degradation of chlorpyrifos into safer and smaller bi-products. Conclusively, by virtues of high surface activity, high reusability (n = 10), stability, and greater charge separation, hybrid ZnO@UF and ZnS@UF nanocomposite may prove as an alternative catalyst for industrial application with intense scope.