Phycosynthesis and Enhanced Photocatalytic Activity of Zinc Oxide Nanoparticles Toward Organosulfur Pollutants

Abstract

A novel eco-friendly procedure was developed to produce safer, stable and highly pure zinc oxide nanoparticles (ZnO NPs) using microalgae Chlorella extract. The ZnO NPs were synthesized simply using zinc nitrate and microalgae Chlorella extract which conducted at ambient conditions. In this recipe, microalgae Chlorella extract acted as the reducing agent and a stabilizing layer on fresh ZnO NPs. UV–visible spectrum was confirmed the formation of ZnO NPs showing an absorption peak at 362 nm. XRD results demonstrated that prepared ZnO NPs has a high-crystalline hexagonal (Wurtzite) structure, with average size about 19.44 nm in diameter. FT-IR spectral analysis indicated an active contribution of algae-derived biomolecules in zinc ions bioreduction. According to SEM and TEM observations, ZnO NPs are well dispersed and has a hexagonal shape with the average size of 20 ± 2.2 nm, respectively. Based on gas chromatography analyses, the optimum 0.01 g/L dosage of ZnO catalyst revealed an effective photocatalytic activity toward the degradation (97%) of Dibenzothiophene (DBT) contaminant as an organosulfur model in the neutral pH at the mild condition. Rapid separation and facile recyclability at five consecutive runs were demonstrated high efficiency and durability of green ZnO nanophotocatalyst. The possible mechanisms of green ZnO NPs formation and the photo-desulfurization of DBT were also proposed.