Experimental Study Of Nanofiltration Membrane With Electrolysis On Treating Dye Wastewater

Dyeing wastewater has been treated as the one of main environmental problems forits great quantity, high concentration, high chromaticity and inorganic salt, complexingredients and poor biodegradability.Nanofiltration membrane technology with low energy consumption and goodremoval efficiency can be employed as advanced treatment to high-salinity dyingwastewater. However, concentration polarization and membrane fouling will decreasemembrane performance. In the system combined electrochemical oxidation andnanofilteration membrane, electrochemical oxidation can help relieve concentrationpolarization and membrane pollution for the concentration decrease on membranesurface, and nanofiltration membrane can separate inorganic salt from dyeingwastewater on the basis of its permselectivity.In order to study the variation of membrane performance, dye chroma, COD, TOCand salt concentration, reactive brilliant red RGB was treated as the object pollutant,Ti/PbO₂electrode and stainless steel net were used as anode and cathode, respectively.In this paper DL and DK membrane produced by OSMONICS company were alsoemployed.The results showed that electrophoretic, electroosmosis and electrochemicaloxidation can prevent the decline of permeate flux caused by concentration polarizationand membrane fouling. In the dying wastewater, decolorization by electrochemicaloxidation reaction through the destruction of main chromophoric groups. In addition,macromolecular organic was degraded into small molecules, H2O and CO₂. COD andTOC values were finally decreased. The separation of inorganic salt from dyeingwastewater also can be realized for the permselectivity of nanofiltration.