The Research Of Organic Solvent-Regenerated Activated Carbon During The Coking Wastewater Treatment

In most cases the coking wastewater which was treated by biochemical process could not meet the criteria.Activaed carbon adsorption was an effective method to resolve this problem,but the prominent problems of this method is that the regeneration method is complex and the adsorbed chemical substances can not be recycled resources. However, in case of taking out the activated carbon which was used to absorb coking wastewater, it would cause environment pollution and wasting of resources.Therefore,to find a reasonable and effective regeneration of activated carbon has theoretical and practical significance.Selecting organic solvents to regenerat actived carbon which was adsorbed coking wastewater, the choice of organic solvents,effect and effect factor of the regeneration of actived carbon have been studied in this paper.Using the GC-MS analyzed the mechanism of regeneration of actived carbon. On the basis of this, activated carbon-SBR-zeolitea,A2-O2-activated carbon-zeolite technology were seleced to treat coking wastewater.Then the analysis of effect on the treatment of coking wastewater by that technology.Using the raw coking wastewater and coking wastewater in biochemical technology as research object. The removel rate of COD in coking wastewater by activated carbon dosage and activated carbon adsorption time have been studued and the analysis of variation of organic matter type and content in wastewater by GC-MS. The results show that activated carbon dosage and activated carbon adsorption time was respectively 9g/100ml,20min,25℃, under this codition,the removel efficiency of organic matter in wasterwater by activated carbon adsorption was best.The result of GC-MS analysis showed that refractory organic such as phenol and benzene and their homologue,heterocyclic compounds and aromatic compounds in coking wastewater was adsorbed well by activated carbon. The heterocyclic compounds, benzene and their homologue, nalidixic and n-position of phenylurea in effluent of coking wastewater was treated byA2-O2 bio filter technology was adsorbed well by activated carbon,and the concentration of organis substance fall below the detection limits of apparatus.The removal ratios of hydrocarbon substance which was adsorbed by activated carbon was weak.Using activated carbon adsorbing coking wastewater and the effluent of coking wastewater was treated by A2-O2 bio filter technology as research object.The ability of activated carbon regeneration by n-pentane, dichloromethane, ether and dodecylbenzene sulphonic acid sodium salt (SDBS) solution and the effect of regeneration rate on actived carbon by n-pentane under the different condition have been investigated. Then, GC/MS were used to analyse the reason of different regeneration rate on activated carbon by different organic solvents.The results showed that activated carbon regeneration by organic solvent process is very feasible. Actived carbon regenerated with SDBS aqueous solution had the worst regereration rate in the three organic solvent and an anionic surfactants,but,the other three organic solvent could regenerat actived carbon many times and have a good effect on actived carbon regeneration (85%) which adsorbed raw coking wasterwater after three regeneration. When the actived carbon which adsorbed coking wastewater in biochemical process was regenerated three times,the regeneration rate of actived carbon which was regenerated by n-pentane increased with the regeneration time and can achieve 90%.The regeneration rate of actived carbon which was regenerated by dichloromethane and ether with the regeneration time increased with the regeneration time is decreased,the final regeneration rate was 73.44%,61.98% respectively.The result of mechamism analysis on activated carbon regeneration showed that the aromatic compounds, naphthalene compounds, heterocyclic compounds, phenol and their homologue on the surface of activated carbon was eluted by n-pentane, dichloromethane, ether and SDBS solution,which on elution capability of hydrocarbon substance and halogenated hydrocarbon was poor.Becase differenr organic solvents have different chemical property and solubility, the eluting capacity of some organic matter which adsorbed on activated carbon was different.When the wastewater was adsorbed by regeneration of activated carbon, it will bring in some new substance induce the concentration of COD in wastewater by activated carbon adsorption was different.On the basis of actived carbon was regenerated by organic solvents,using the actived carbon as adsorbent to treat coking wastewater Selecting activated carbon-SBR- zeolite andA2-O2- activated carbon-zeolite technology to treat coking wastewater. The operation effects of actived carbon as SBR pre-treatment and A2-O2 post-treatment to treat the coking wastewater have been investigated. The result of experiment showed, The removal capacity of COD in coking wastewater by A2-O2-activated carbon-zeolite technology is greater than activated carbon -SBR- zeolite technology,and the effluent of coking wastewater in A2-O2-activated carbon-zeolite technology could meet the national emission standard. The analysis of economic feasibility on this system and n-pentane-regenerated actived carbon showed that the economics of this system and regeneration method were better.