Ultrafiltration-electrodialysis Coupling Dehydration Of Organic Waters

Great deals of organic salty liquid wastes are discharged by industries of chemical engineering,pharmacy and paper making,which are easy to lead irreversible environmental pollution.Pharmacy and paper making,which are easy to lead irreversible environmental pollution.High concentration organic liquid wastes cannot be disposed effectively by routine treatment methods.So,development and study of organic salty liquid wastes is strigent need in this field.A new membrane separation system,the electrodialysis with ultrafiltration membranes,was put forward to treat organic salty liquid wastes in this dissertation.The electrodialysis with ultrafiltration membranes is a novel membrane separation technology in which ultrafiltration membranes are stacked or replaced partial ion exchange membranes by ultrafiltration membranes in conventional electrodialysis cell.In this paper,the electrodialysis with ultrafiltration membranes was used to separate the inorganic ions from the organic salty liquid.Firstly,by comparing with different coupled methods,the relatively more suitable stack was selected,in which anion exchange membrane was replaced by ultrafiltration membrane in conventional electrodialysis cell.And factors which have influence on ions migration,including stack voltage,feed liquid flow rate and velocity ratio were carefully examined.It was found that the voltage of 6.5 V was favorable to desalination.Oversize voltage will lead to membrane pollution.Flow rate of feed compartment has significant impact on the desalination rate.The smaller feed flow rate,the longer the retention time,the higher the desalination rate is.When the flow rate of feed compartment equals that of concentrate compartments,there is not pressure difference between the two compartments,which reduces the organic pollution of the membrane.Than the effects of different membrane materials on the desalination process were studied.It was found that ultrafiltration membrane is more difficultly to be polluted by organics,when compared with anion exchange membranes.Finally,three-stage electrodialysis was designed to achieve continuous water desalination.After 8h operating,the effluent water quality is relatively stable.Results indicate that ultrafiltration membrane was slightly contaminated.In this study,the organic water desalination membrane reactor experimental system,electrodialysis with ultrafiltration membranes,is established.,and the separation of organic and inorganic ions was conducted and good results have been achieved.Systematic analysis of the operation mode of the separation process and mass transfer process of water desalination technologies for organic development can provides new ideas and technical support.