Facile synthesis of TiO2-PC composites for enhanced photocatalytic abatement of multiple pollutant dye mixtures: a comprehensive study on the kinetics, mechanism, and effects of environmental factors

In the recent era, the inevitable emergence of versatile micropollutants in ground and surface water has become a serious concern for the long-term sustainability of the environment. Most of the recent studies, conducted to minimize water pollution, are mainly limited to either single or binary pollutant-based analyses. Hence, photocatalytic degradation of a multicomponent pollutant dye (four components) mixture was studied in the present work. Here, the economical TiO2-processed carbon (PC) nano-/microcomposite-mediated degradation of a pollutant dye mixture in aqueous solution under continuous UV irradiation was investigated and compared with bare TiO2 photocatalysis. The overall degradation kinetics, degradation mechanism and the impact of several environmental factors on photocatalytic decomposition of pollutant dye mixtures have also been identified and addressed. It is observed that the TiO2-PC composite-mediated photocatalysis has superior degradation performance over that with bare TiO2 treatment. Consequently, the degradation kinetics parameters have also shown significant improvements for cases of TiO2-PC composite-mediated photocatalysis, for which the degradation rate constant has shown an improvement up to 22%, mainly due to the synergistic effect of the TiO2-PC composites. However, the mineralization level is barely improved. It may be noted that the catalyst reusability test has also shown the superiority of TiO2-PC composites over bare TiO2. In addition, the environmental factors such as salt concentration, pH, temperature, mixing/stirring speed and catalyst dose have shown significant influences over the degradation efficiency of these photocatalysts. It is interesting to observe that the alkaline condition (pH > 9.0) favors the improved photocatalytic performance of TiO2-PC composite.