Effects of different zinc oxide morphologies on photocatalytic desulfurization of thiophene

Abstract

Zinc oxide (ZnO) nanoparticles are superior photocatalysts for pollutant degradation due to their stability, low hazard, and high photosensitivity. The morphology of this material is one of the key factors influencing the performance of pollutant degradation. In fact, studies on the effects of different ZnO morphologies on thiophene desulfurization via photocatalysis process are limited. Thus, this study focuses on the performance of different ZnO morphologies for thiophene desulfurization. Nine ZnO nanoparticles were synthesized and categorized into two groups, namely flower-like and non-flower-like ZnO. Flower-like ZnO included flakes, clusters, rods, and needles, while the non-flower-like ZnO comprised nanoballs, short-nanorods, nanocubes, and nanoporous. The physical properties of all ZnO morphologies were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier-transform infrared (FTIR), and compared with commercial ZnO. From the findings, flower-like ZnO flakes showed the highest performance in thiophene desulfurization (30%). High pH and turbidity reduction in the permeate confirmed that the thiophene compound in the solution was highly degraded after treatment. Moreover, all ZnO morphologies applied to pseudo-second-order models due to higher linear regression (R-2) values. Greater thiophene desulfurization was indicated by the highest Ce value of ZnO flakes (909.09 mg/g). The optimum conditions for thiophene desulfurization were at pH 7 and 0.05 g/L ZnO flakes loading for 90 min contact time.