Synthesis of a silica matrix with ZnO nanoparticles for the fabrication of a recyclable photodegradation system to eliminate methylene blue dye

Abstract

In this study, a silica matrix was utilized as a substrate for zinc oxide nanoparticles (ZnO NPs) to enhance their photocatalytic activity for the degradation of methylene blue (MB) dye. The recovery of the prepared material was also investigated. To compare the performance of the prepared material with ZnO NPs and bare silica, various analyses were conducted. ZnO NPs were synthesized via a coprecipitation method and characterized using Fourier-transform infrared spectra and X-ray diffraction (XRD). The XRD results revealed highly crystalline ZnO NPs with an average crystallite size of less than 100 nm. The presence of ZnO on the silica matrix was confirmed using scanning electron microscopy (SEM) and EDX analysis. The prepared ZnO NPs showed enhanced photocatalytic activity for the degradation of MB dye, and reasonable material recovery was also observed. The silica-coated ZnO NPs degraded MB dye by 97% in just 40 min and retained their photocatalytic activity for up to 20 cycles. In comparison, bare silica exhibited effective photodegradation but lost its photodegradation capacity after five cycles. ZnO NPs without silica coating took 5 h to degrade MB dye. The significant accomplishment in this study is the development of novel materials with high recoverability, simple preparation, and efficient photocatalytic activity. In the future, ZnO NPs supported on a silica matrix can be utilized for various applications.