Synthesize and characterization of a novel sol–gel-driven Bi2O3 semiconductor: complete degradation and fast photocatalytic activity for paracetamol

Abstract

The pollutants are getting released fluently as a waste from the pharmaceutical pollutants leading to the decrease in quality of water. The widespread occurrence of pharmaceutical pollutants poses a serious threat to the environment and human health. Besides, today carbon dioxide emissions and other forms of pollution appear to be a critical global issue. In this study, Bi₂O₃ catalyst has been prepared via co-precipitation (CP) and a facile sol–gel (SG) methods used as photocatalyst for the degradation of paracetamol (PAR) under different light sources. The preparation method has significant effect on the optical and structural properties of the catalysts. The tetragonal phase of Bi₂O₃, the presence of more surface OH groups and lower band gap energy remarkably improved the sun-light-driven photoactivity of PAR. The photocatalysts have been characterized by some structural and morphological analysis techniques and optical analysis techniques. In addition, zeta potential (ZP) measurements were performed to explain the impact of the initial pH of solution on photocatalytic degradation. Identification of PAR and the reaction intermediates was determined using Liquid Chromatography-Mass/Mass Spectrometry (LC-MS/MS) technique. Higher photocatalytic activity was obtained with the Bi₂O₃-SG (1:2) catalyst at pH 5 compared to the activity of Bi₂O₃-CP. Moreover, Bi₂O₃-SG (1:2) achieved the highest photocatalytic activity at pH 3. The photocatalytic activity was enhanced, and the time required for 100% degradation of PAR was reduced from 60 min to 30 min and 15 min under UVB irradiation and directly sun light irradiation, respectively. The highest reaction rate (0.086 (min⁻¹)) were obtained in 15 min with the Bi₂O₃-SG (1:2) catalyst. The results showed TOC removal could be achieved in 60 min 99.19 and 88.97% for Bi₂O₃-SG and Bi₂O₃-CP, respectively. In general, sol–gel-driven Bi₂O₃ as a flower and needle-like morphology, can reveal excellent opportunities in the photocatalytic technology.

Graphical Abstract