Research Of Photo-Electric Coupling Catalytic Oxidation For The Refractory Organic Wastewater With High Chloride Treatment

As a new pollution treatment technology,photocatalysis and electric catalytic oxidation has been very popular in recent years due to its thorough degradation of organic matter,mild reaction condition,low equipment investment,no secondary pollution and so on.In this paper,the photo-electric coupling catalytic oxidation on refractory organic wastewater with high chlorine ion was investigated.Firstly,the TiO₂ photocatalyst with catalytic activity was composed using the common laboratory sol-gel method,and subsequently XRD characterization and aniline degradation experiment were conducted to test the photocatalytic performance of the produced TiO2 photocatalyst.Result showed that the prepared TiO2photocatalyst has good photocatalytic activity.Additionally,through the single factor experiment,the impact of initial pH of experimental samples,initial organic matter concentration,reaction time,catalyst dosage,load voltage of electrode and oxidant on degradation of organic matter by photocatalysis and electric catalytic oxidation was studied.Experiment results were as following:when the initial pH of water samples was alkaline,the organic matter degradation rate was much higher than water samples of which the initial pH was acid.The highest degradation rate of aniline appeared when the initial organic concentration of aniline was 2000 mg/L.After 2.5 h light reaction,organic matter degradation rate of water samples had reached 80%,however the organic matter degradation rate increased finitely even continuing to increase the system reaction time.The organic matter degradation rate increased continuously with light catalyst dosing quantity increasing from 0.5 g/L to 2.0 g/L,but organic matter degradation rate began to reduce when the light catalyst dosing amount reached 3 g/L.When the load voltage on both ends of catalytic electrodes increased from 4 v to 20 v,the organic matter degradation rate contributed by system increased also,and when the load voltage continued to increase,the organic matter degradation rate contributed by system tended to be stable.The added oxidant H2O2 could obviously promote the effect of photocatalysis and electric catalytic oxidation to degrade organic matter,but excessive dose started to reduce the system efficiency of the organic matter degradation.Then the synergy effect and the synergistic reaction mechanism the light-electricity coupling catalytic oxidation system were explored and analyzed through experiments,and the influence of chlorine ion on the synergy effect of light-electric coupling catalytic oxidation system and the change of chloride ion content before and after reaction were observed.It was found that the existence of chlorine ion had a promoting effect on light-electricity coupling catalytic oxidation system in a certain range,and the system of organic matter degradation rate increased with the increasing of chloride ion concentration,but when the concentration of chloride ion increased to more than 9000 mg/L,organic matter degradation rate decreased.As experiment progressed,the content of chloride ions was decreasing.When the initial chloride ion concentration was 5000 mg/L,it could decrease to about 2600 mg/L after 2.5 h reaction,which could confirm that light-electricity coupling catalytic oxidation also had the effect of synchronous desalting simultaneously in the degradation of organic matter,.It was found that hydroxyl radicals produced by light-electricity coupling synergy system were more than by single photocatalytic system and catalytic oxidation effect was better by hydroxyl free radical inhibitor experiment.