Study On Regeneration Of Powdered Activated Carbon Used For Reverse Osmosis Concentrate Treatment

With the development of the reverse osmosis(RO)membrane,RO technology has found an increasingly wide utilization in water reclamation.While a large number of RO can be reclaimed,a RO concentrate(ROC)containing all of the constituents rejected by the RO membrane is also generated.After the pre-processing,the organic pollutant have enriched,it usually includes small molecule compounds and nonbiodegradable organics.If the ROC is discharged directly without any treatment,it would cause severe pollution to the water environment.Therefore,the removal of organic matter from the ROC becomes a hot topic.Among the treatment methods,activated carbon(AC)adsorption is one of the feasible technologies.However,the adsorption of AC just only transferred the organics to the solid AC,without proper disposal,it would not only generate a large amount of solid waste,but remains a threat to environmental safety.Wet oxidation(WO)regeneration of AC was conduct in mild conditions,to a certain extent,it can not only recover AC,and can also oxidize or convert most of the adsorbed organic matters to biodegradable organic acid,reduce the impact on the environment.The two main factors for the regeneration,i.e.regeneration temperature and time were investigated.The optimum condition of regeneration for this experiment was the regeneration temperature of 200?,the regeneration time of 60 min,oxygen pressure of 0.1 MPa.In addition,the successive adsorption-regeneration under optimum conditions was conduct,the stability of the PAC was verified,and the characters of regenerated PAC were analyzed after the experiment.Because of its mature technique,and the operation is relatively simple,solvent regeneration of AC is also an important research in the regeneration of AC.On the basis of previous work,two kinds of regeneration solvent(methanol and ethanol)were studied on the regeneration of PAC,the relationship between equilibrium concentration and adsorption amount was investigated,the characteristic of the regenerated PAC after one stage and two stage regeneration,and the relationship between the regeneration rate and microporous were also analyzed.At the same time,the successive adsorption and regeneration on different ratio of solid-liquid was studied,in order to explore the change of regeneration rate and the characteristics of PAC after different regeneration times.The results showed that the methanol and ethanol could achieve better regeneration effect for one stage when solid-liquid ratio was 100 g/L.At this condition,it could get higher regeneration rate,have less damage of PAC,and performance well in the successive cycle of adsorption and regeneration.In the view of the regeneration effect and economic analysis,the results show that ethanol has advantage in the price,but there are re-pollution problem for the environment.Although the pre investment of the WO is larger,it has the advantages of good regeneration effect and no re-pollution etc.With the progress of technology,it would have broad prospect in the practical application.