Microwave - Activated Carbon Co-processing Of Coking Wastewater Process Research

Coking industry occuping a important position in industry developing position of China.A large amount of coking waste water containing pernicious compounds was brought following the production of fine cokes,which contain pernicious compound.In this paper,on basis of a brief summarization of the disposal of coking waste water,a new method which is analogous with wet catalytic oxidation(WCA)was put forward by adopting microwave-activated carbon to dispose the coking waste water.The coking waste water before and after biochemical treatment was treated by microwave(MW)heating and by using coconut shell activated carbon and spent carbon as catalyst.The purpose of this work is to try to improve the biodegradability of the coking waste water before biochemical treatment and the degradability of the some organism,resolve the problem of the pollutant beyond the standard in the coking waste water after biochemical treatment.After the exploration of the effect of each factor on CODcr wipe ratio,the optimal technique parameters were obtained.1.The optimal technique parameters of the coking waste water systems before biochemical treatment disposed by two kind of MW carbons were obtained as follows:1)for microwave-coconut shell activated carbon system:MW power was 700W;radiation time was 120S;ventilate was 2L/min;initial PH was 7.2)for microwave-spent carbon system:MW power was 700W,radiation time was 120S,ventilate was 2L/min,initial PH was 7 or 3.The increase of carbon can approve the wipe ratio of the two systems, but along with the increase of the cost.When the carbon is 2.5g,the wipe ratio of COD_crreaches 40%for MW coconut shell activated carbon system and 50%for MW spent carbon system.2.The optimal technique parameters of the coking waste water systems after biochemical treatment disposed by two kind of MW carbons were obtained as follows:1)for microwave-coconut shell activated carbon system:MV power was 700W;radiation time was 120S;ventilate was 1L/min;initial PH was 7;the AC was 5.0g.2)for microwave-spent carbon system:MV power was 700W;radiation time was 120S;ventilate was 1L/min;initial PH was 7 or 3;the spent carbon was 2.5g.The increase of carbon can approve the wipe ratio for two systems.When the carbon is 2.5g, the wipe ratio of COD_crreaches 60%for MW coconut shell activated carbon system and 70%for MW spent carbon system.3.In comparison of the effect of both microwave-coconut shell activated carbon and microwave-spent carbon on COD wipe ratio of the coking water before and after biochemical treatment,the result indicates that the microwave-spent carbon was more effective than coconut shell activated carbon.For the coking waste water system before biochemical treatment, the different microwave absorption of two kinds of carbon was the reason for the different results of treatment.Under the microwave field,the average heating temperature of coconut shell activated carbon increased as 67℃/min,while the spent carbon increase as 95.8℃/min.For the coking waste water system after biochemical treatment,on the one hand,the biochemical treatment led to the break of carbon chains and the open of rings in long chain and heterocyclic compounds,and most residual organic compounds are small molecules.A part of macromolecular organic compounds were decomposed in the pre-adsorption and pre-treatment of MW-AC.Along with the MW-AC treatment,the absorption and degradation of small molecules become the main contribution to the change of COD. The different pore structures of two kinds of carbon were the primary reason for the different effect of both disposal systems.The spent carbon has more micropores and larger pore volumes than coconut shell activated carbon.On the other hand,the spent carbon has better "homothetic photocatalytic degradation" effect and "heat point" effect than coconut shell activated carbon.Therefore,the treatment of coking waste water by microwave-spent carbon is more effective than that by microwave-coconut shell activated carbon.Therefore,This thesis carried out a actively explore for coking waster water treatment,and open up a new way for microwave application.