Study On Photocatalytic Degradation Of Pentachlorophenol And Mathematic Simulations

Pentachlorophenol (PCP) is a typical organic chloric pesticide, which is one of the most persistent organic pollutants. It is harmful to human and the environment. The research on reducing and controlling pollutions caused by PCP has attracted wide interests in the field of chemical engineering internationally. This study focuses on the photocatalytic degradation of pentachlorophenol and the effects of photocatalytic degradation, process analysis, technique development and mathematic simulation have been investtigated.The adsorption characteristics of PCP on the surface of catalyst were determined from the adsorption isotherm experiments. The results are used to fit the absorption parameters of the Langmuir model. The kinetic equation of the photocatalytic degradation of pentachlorophenol at lower concentration, which was said as L-H equtions, has been presented. From the study of PCP's photo catalytic degradation process, three intermediate were detected: 2,3,4,5-tetrachlorophenol, 2,3,4,6- tetrachlorophenol and 2,5- dichlorophenol.The effects of of pH of the solution, quantity of catalyst, light intensity, sparging rate and dosage of potassium persulfate on the photocatalytic degradation process of PCP have been investigated. The results showed that degradation rate could be accelerated by a higher pH or a more powerful light intensity, but the quantity of catalyst, sparging rate and dosage of potassium persulfate exhibited optimal values respectively. The synergistic effect of ultrasonic to photocatalytic degradation process of PCP has been proved by mesurement of TOC and the experiments of discorloring of methylene blue.Ultrasonic, photocatalysis and membrane were combined to develop a self-style recirculated membrane ultrasonica assisted photocatalytic reactor. With the response surface method (RSM), the optimal operationing conditions of this reactor were obtained: 0.97 g of TiO₂, 0.19m³Â·h^-1 of sparging rate, 17.00 mg dosage of K₂S₂O₈, and 98.6% degradation rate.Based on the analysis of kinetic characteristics of photocatalytic degradation of PCP and the expressions of reactive equations, computational fluid dynamics simulations were done to study this photocatalytic degradation process. The simulation results agree well with the experimental data.. At last, the model of two phases was used to simulate the hydraulics and concentration field. The results showed that top inlet was better than inferior inlet, and 60°was the better choice in one inclined inlet.