Optimization and kinetic studies of photodegradation of Rhodamine B with immobilized Ag-, S-, and N-doped TiO2 under visible irradiation: using Box–Behnken designs (BBDs), multivariate curve resolution (MCR-ALS) and parallel factor (PARAFAC) analysis

This study is based on a two-stage approach. First, an experimental design was used in the optimization for the photodegradation of Rhodamine B dye (RhB) with Ag-, S-, N-doped TiO2, with the concentration of RhB, pH and reaction time as optimization parameters. Second, the degradation rates were estimated through a kinetic study of RhB at the optimal conditions. The kinetic analysis was performed through the measurement of fluorescence excitation-emission matrices (EEMs) coupled with chemometrics. The number of the chemical components involved in the photodegradation process and their concentration and spectra profiles was established by multivariate curve resolution (MCR-ALS) and parallel factor (PARAFAC) analysis.