Chemical Engineering Journal, Vol.343, 95-107, 2018
A new approach in sono-photocatalytic degradation of recalcitrant textile wastewater using MgO@Zeolite nanostructure under UVA irradiation
Dyes are hazardous for aquatic environment and human health, due to their adverse effects on human health such as toxicity, mutagenic, skin irritation and carcinogenic. Therefore, it is necessary to efficiently remove dyes from wastewater, before discharging into the environment. The most principal objective of this research was evaluation of the capability of sono-photocatalytic process over MgO supported by zeolite heterogeneous nano-composite (MgO@Z), as a first study, to treat textile wastewaters. The influence of different experimental factors such as, solution pH, reaction time, catalyst loading, irradiation intensity and ultrasonic power on the system efficiency was studied. A plausible oxidation mechanism was also proposed. The catalytic performance of MgO@Z in degradation of organic matters was improved substantially, in the presence of UVA and US irradiations. Results showed that with decreasing pH from 11 to 3, the removal efficiency increased and under optimized conditions the removal rates of COD was 76% within 240 min reaction. A remarkable synergistic effect was observed between MgO@Z and US and UVA irradiations in degrading pollutants. Under optimum conditions, the mineralization degree of higher than 97% was obtained at longer reaction times of around 10 h. Recycling tests demonstrated that the degradation efficiency dropped only by 14%, after four successive runs. In conclusion, coupling of MgO@Z with US and UV irradiations can be utilized as a novel and promising approach to treat textile wastewaters in practical applications.