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In this work, we have proposed a new approach to study the mechanism of crystal violet (CV) photodegradation on TiO2 surface using kinetic Monte Carlo simulation. The TiO2 surface was considered as a set of reactive centers, which is essential in dye photodegradation. A new variable "the effective photon concentration" (Ieff) is defined. A detailed chemical understanding of the photocatalytic reaction is provided. This approach provides a simple and effective method to find the optimal conditions of the studied system. This goal was achieved by investigating the effects of some operational parameters, including initial concentration of CV, pH, loading TiO2, light intensity and volume, on the degradation percent, and also, on the effective photon concentration. The perfect agreements between the experimental and simulated data at different conditions confirmed the proposed approach for describing the CV photodestruction. Also, the simulation results indicated that: (1) a significant fraction of the scattered UV irradiation into the reaction vessel does not lead to charge carrier generation; (2) the generation and recombination of charge carriers have crucial roles in the photodegradation. This is the first time that a method based on the reactive centers is employed to investigate the dye degradation by a photocatalyst.

This work presents a new approach and a comprehensive mechanism to study the kinetics of the photodegradation of the organic pollutants. The vital role of various operational factors on the degradation of the organic pollutants is explained using this method. The proposed approach is based on the simple strategies and a powerful computational method. Two new variables "the effective concentration of photon" (Ieff) and "the effective concentration of the reactive-centers" (RC) are defined to better understanding the effect of operational parameters on the organic pollutants photodegradation. The optimum conditions of the photocatalytic degradation can be determined with the help of this method. This approach was used to study the kinetics of photodegradation of the organic pollutants on the A − doped M x O y /B photocatalysts. The provided mechanism has been examined with the some experimental data.The high correlations between the experimental data and the fitting results under different conditions prove this mechanism could be reliable.

This work presents a new approach and a comprehensive mechanism to study the kinetics of the photodegradation of the organic pollutants. The vital role of various operational factors on the degradation of the organic pollutants is explained using this method. The proposed approach is based on the simple strategies and a powerful computational method. Two new variables “the effective concentration of photon” (Ieff) and “the effective concentration of the reactive-centers” (RC) are defined to better understanding the effect of operational parameters on the organic pollutants photodegradation. The optimum conditions of the photocatalytic degradation can be determined with the help of this method. This approach was used to study the kinetics of photodegradation of the organic pollutants on the A - doped MxOy/B photocatalysts. The provided mechanism has been examined with the some experimental data. The high correlations between the experimental data and the fitting results under different conditions prove this mechanism could be reliable.