The Study On Pre-treatment Of Coking Desulfurization Wastewater By Catalytic Oxidation And Phase Equilibrium Of Studied System

The coking desulfurization wastewater is a kind of complicated composition,serious pollution industrial sewage.Usually,the coking desulfurization wastewater contains high concentrations of sulfide ion,thiocyanate ion,sulfate radical,thiosulfate anion,sodium or ammonium ion and so on.Additionally,the chemical oxygen demand(COD)and alkalinty of solution are very large for the research wastewater.In this paper,the coking desulphurization wastewater was taken as the research object,the pre-treatment of coking desulphurization wastewater by catalytic oxidation of metalloporphyrins and determination and correlation of solid-liquid equilibrium data of sodium salt and ammonium salt in oxidation reaction system of coking desulfurization wastewater,the specific research work is as follows:Firstly,the pre-treatment reaction of coking desulfurization wastewater and the analysis of coking wastewater index were established.The concentrations of sulfide ion,sulfite ion,thiosulfate anion were qualitatively analyzed by iodometric method,the concentrations of sulfate ion was qualitatively analyzed by barium ion precipitation method,SCN-was quantitatively analysed by UV spectrophotometry,COD was quantitatively analysed by potassium dichromate method;Secondly,the reaction of metallporphyrin catalytic oxidation pre-treatment coking desulfurization wastewater was studied.the removal rate of COD and SCN-as the evaluation index to sieve out the best catalyst,and screening TSPPMnCl as the optimal catalyst in the chosen metalloporphyrins.Considering the reaction time,dosage of oxidant,reaction temperature,dosage of catalyst,air flow influence on the pre-treatment of coking desulphurization wastewater by catalytic oxidation of TSPPMnCl,which had been investigate by orthogonal experiment.Base on the removal rate of COD and SCN-,the best conditions as follow:the reaction time was 6 h,the reaction temperature was 80?,dosage of catalyst was 6 cm3,dosage ofhydrogen peroxide was 6 cm3,the flow of air was 400 cm3·min-1.Under the bestexperimental conditions.the experiment was repeated two times.the removal rate of thiocyanate ion and chemical oxygen demand can reach 76.05%and 77.64%respectively.Thirdly,under experimental tamperature ranged from 278.95 to 337.65 K,thesolid-liquid equilibrium data of sodium sulfide nonahydrate,sodium thiosulfate pentahydrate,anhydrous sodium sulfite,sodium sulfate and sodium thiocyanate in sodium hydroxide + H2O solution and ethanol + H2O solution were measured respectively by using the laser dynamic device by self-designed and assembled.The Apelblat equation and empirical equation were used to correlate the experimental solubilities and the corresponding model parameters were obtained.The result showed that the relative average deviations of Apelblat equation and empirical equation were less than 6.57%and 4.23%,empirical equation could correlate the experimental solubilities better.Fourthly,under experimental tamperature ranged from 280.65 to 340.55 K,the solid-liquid equilibrium data of sodium sulfide nonahydrate,sodium thiosulfate pentahydrate,anhydrous sodium sulfite and sodium thiocyanate sodium in sodium sulfate + H20 solution were measured respectively by using the laser dynamic device.The Apelblat equation and empirical equation were used to correlate the experimental solubilities and the corresponding model parameters were obtained.The result showed that the relative average deviations of Apelblat equation and empirical equation were less than 4.50%and 1.96%,empirical equation could correlate the experimental solubilities better.Fifthly,under experimental tamperature ranged from 280.65 to 327.15 K,the solid-liquid equilibrium data of ammonium sulfate and ammonium thiocyanate in ethanol + H2O solution were measured respectively by using the laser dynamic device.The Apelblat equation and empirical equation were used to correlate the experimental solubilities and the corresponding model parameters were obtained.The result showed that the relative average deviations of Apelblat equation and empirical equation were less than 2.36%and 0.64%,Apelblat equation and empirical equation could correlate the experimental solubilities well.