Study On Regeneration Method Of Activated Carbon Modified By Methylene Blue

Dyeing wastewater has the characteristics of deep chromaticity,high pollutant concentration,complex compositions,difficult treatment,too large quantity water and uneven discharge and so on.It is difficult to meet the national discharge standard by conventional treatments,so it is necessary to carry out advanced treatment.Activated carbon is widely used in advanced treatment of dyeing wastewater.When activated carbon is absorbed and saturated,if it is discarded directly,its value cannot be fully made use of,but even worse,it may cause environmental pollution.Therefore,it is necessary to find out an effective regeneration method of activated carbon,so as to reduce the pollution to the environment and save resources.There are many disadvantages in the single activated carbon regeneration technology,such as low regeneration degree,high loss of activated carbon and poor economic benefits,so combined regeneration has become a research hotspot.In this experiment,the adsorption properties of activated carbon were improved by modification of activated carbon,thus reducing the amount of activated carbon added,and the method of activated carbon regeneration combined with chemistry and microwave was studied,which could effectively improve the regeneration effect of activated carbon and reduce the time of regeneration.The main research content of this paper was as follows:taking methylene blue as the representative substance,and exploring:?1?The optimal regeneration conditions and regeneration efficiency of three single regeneration modes were studied:Fenton reagent oxidation regeneration,based on the regeneration of sulfate radical oxidation and microwave irradiation regeneration.?2?Activated carbon was regenerated by Fenton-microwave combined method and based on sulfate radical and microwave combined method.?3?The possibility of regeneration in a microwave continuous flow reactor was studied by applying the method based on sulfate free radical and microwave combined regeneration.The effects of microwave irradiation time and power were investigated,and multiple regeneration was carried out under optimal conditions to study its feasibility.?4?To study the practical performance of the combined method based on sulfate radical and microwave for practical printing and dyeing wastewater.?5?The regeneration mechanism of activated carbon was elucidated by means of SEM,Boehm and FTIR of raw carbon,modified carbon and various regenerated carbon.The specific results of this study were as follows:?1?In the single reproduction method,the optimum condition of Fenton method is n?H₂O₂?:n(Fe²⁺)=15:1,and the percentage of H₂O₂ was 10%,pH=3,the reaction time was 40 min,and the reaction temperature was 55?.The result showed that regeneration rate could reach 63%;The optimum conditions were as follows:the mass concentration of persulfate was 15%,the addition percentage of H₂O₂ was 10%,the reaction temperature was 50?and the reaction time was 60 min,the regeneration efficiency could reached 73%.The optimum conditions for microwave regeneration were power 595 W,irradiation time was 90 s,the result showed that regeneration rate could reach 58%.?2?In combined regeneration,when the microwave irradiation time was 45 s,the microwave irradiation power was 700 W,Fenton-microwave combined regeneration method and the free radical-microwave combined regeneration method based on sulfuric acid root reached 79.58%and 91.97%respectively.?3?In the continuous flow test,when the irradiation time was 40 s,the irradiation power was 1500 W,the highest regeneration efficiency was 85.60%,and it regenerates repeatedly under this condition,the first 3 regeneration rate is high,reaching 75%,after gradual decline,the value can still be more than 50%.The obtained adsorption penetration curve was fitted with Logistic model,and the fitting degree was more than 99%.?4?Under the optimum conditions,the saturated activated carbon adsorbed on simulated wastewater and the saturated activated carbon adsorbed on actual wastewater were regenerated by the combined regeneration method based on sulfate radical and microwave,respectively.The applicability of combined regeneration method based on sulfate radical and microwave was studied.The results showed that the regeneration effect of activated carbon adsorbed on different simulated wastewater can reach more than 86%,and the removal of COD_Cr from water by saturated activated carbon adsorbed on actual wastewater is close to the original carbon phase after regeneration.The results showed that the efficiency of joint regeneration is obviously improved on the basis of a single regeneration method.In continuous flow test,the time and power of microwave irradiation have great influence on the combined regeneration effect.The method based on the free radical-microwave combined regeneration of activated carbon has a good effect and has a certain effect on the regeneration of activated carbon in the actual printing and dyeing wastewater.