Sonocatalytic degradation of nitrobenzene with metal oxide clay nanocomposites

BACKGROUND: The presence of a wide range of persistent toxic organic pollutants in industrial effluents poses a serious threat to human and environmental health, emphasising the necessity for developing cost-effective methods for treating toxic effluents. This study focuses on the synthesis, characterization and evaluation of metal oxide [iron (Fe), copper (Cu) and zinc (Zn)]-doped clay composite for the sonocatalytic degradation of nitrobenzene (NB) in the presence of ultrasound. RESULTS AND CONCLUSIONS: Among the metal oxides studied, Cu and Fe oxide-modified clay performed better in the degradation of NB (similar to 99% in the presence of air) compared to a ZnO/clay composite. Process optimization studies were carried with CuO/clay composite at different pHs (2.5-11.5), feed concentrations (50-200 mg L-1) and catalyst loadings (0.25-1.0 g L-1). Neutral pH conditions and higher catalyst loadings of 1 g L-1 were found to be optimal for the efficient degradation of 50 ppm NB. Among the scavengers tested, ethylenediamine tetra acetic acid exhibited strong scavenging effects, resulting in reduced NB degradation compared to isopropyl alcohol and tin tetrachloride, regardless of the scavenger concentration (0.5 and 40 mmol L-1). The catalyst was found to be sufficiently stable for up to four cycles under identical conditions. Additionally, these materials were found to be effective in the degradation of other pollutants [Terephthalic acid, Rhodamine-B, Ciprofloxacin]. These findings contribute to the development of cost-effective strategies for the treatment of industrial effluents, reducing the risks posed to both the environment and human health. (c) 2023 Society of Chemical Industry (SCI).