Kinetic and mechanistic investigations on the degradation of carbamazepine by solar simulated light/N-TiO2/persulfate system

In current study, the degradation of carbamazepine (CBZ) by various advanced oxidation processes (AOPs) such as solar simulated light (SSL), SSL/N-TiO2, SSL/persulfate (SSL/PS), and SSL/N-TiO2/PS was investigated. SSL alone was not capable of sufficiently degrading CBZ, achieving only 7.3% degradation of CBZ after 180 min of light irradiation at pH 6.0. The degradation of CBZ was observed to be 41.2, 48.3, and 98.7% using SSL/PS, SSL/N-TiO2 and SSL/N-TiO2/PS systems, respectively, after 180 min, using 2 mM of PS, 6 mg L− 1 of CBZ and 0.5 g L− 1 of the photocatalyst (N-TiO2). The removal of CBZ followed pseudo-first-order kinetics with the observed rate constant (kobs) values of 0.0040, 0.0064 and 0.0220 min− 1 for SSL/PS, SSL/N-TiO2, and SSL/N-TiO2/PS systems, respectively. Additionally, the impact of various operational parameters such as initial concentration of CBZ, photocatalyst dosage, pH, temperature, and inorganic anions on the photocatalytic degradation of CBZ, using SSL/N-TiO2/PS system, was also evaluated. Moreover, four degradation products (DPs) of CBZ by SSL/N-TiO2/PS process were detected. To assess the potential toxicity of the treated water, the Ecological Structure-Activity Relationship (ECOSAR) program was employed to estimate the aquatic toxicity of CBZ and its DPs. This study provides valuable insights into optimizing AOPs for wastewater treatment, emphasizing the importance of oxidant selection and catalyst integration in achieving superior performance in terms of water contaminants degradation.