The Study Of Photocatalytic Degradation Of Dyestuff Wastewater With TiO₂ By Photoreactor

Photocatalytic oxidation is a technique for removal of pollutants from aqueous and ail-streams by semiconductors such as TiO2, ZnO. Its has become a new advanced oxidation processes (AOPs) and has widely used because of high- efficiency, low- power, wide-safety. Therefore, it is important that photocatalytic oxidation be developed.According to work principle and configuration of the photocatalytic reactor, inner-circulation photoreactor was made in this article. The photocatalytic degradation of methyl orange with titanium dioxide in self-made inner-circulation photoreactor was investigated and got a successful removal in this work. In the best performance, color removal was 92.1% and basic rose red was decomposed completely. Experiment indicated that suspended TiO2 has higher radio than supported TiO2. The parameters such as the ratio between inter-diameter and outer-diameter, state of titanium dioxide, good transmission in G-L-S three phase systems, initial chroma of waste water has great influence in the photoreaction. The best condition is: ratio between inter-diameter and outer-diameter is 9/15, air bubbling flow is 0.015m/s. Without air bubbling, the degradation is very slow. Air bubbling can accelerate the decomposition reaction notable. Through the analysis of the experiment data, the apparent reaction of heterogeneous photocatalytic reaction of methyl orange in water under air bubbling is known to be one. The apparent kinetic in different conditions constants were calculated and the preliminary kinetic model was built.Through the analysis of Total Organic Carbon (TOC), UV-VIS and Chemical Oxygen Demand (COD), the process of basic rose red degradation was determined and mechanism of photocatalysis was deduced. Studies illustrated that the strong oxydic free radicals attacked the conjugated radical first. The process of decolor and the removal of TOC is not simultaneous. Firstly, the reaction is decolor process. Secondly, intermediate is decomposed. Basic rose red changed into colourless and steady intermediate because TOC degraded little in initial stages. Through the analysis of the degradation process of methyl orange and Basic Rose Red, Basic Rose Red was much vivacious than methyl range. Basic Rose Red can make specific reaction.Otherwise methyl orange has retardarce in initial stages.