A novel in situ membrane cleaning method using periodic electrolysis

Membrane fouling is the major problem during the practical application of membrane separation processes in industry and water treatment. Therefore a search for novel efficient methods of membrane cleaning is currently of crucial importance for membrane-based technologies. The paper describes a new method of membrane cleaning, which is based on periodic electrolysis using a novel electrically conductive membrane to remove/prevent membrane fouling. The membrane consists of a thin electrically conductive layer of multi-walled carbon nanotubes (MWCNTs) deposited on the membrane׳s surface. The deposited MWCNTs allow the membrane to function as a cathode in an electrochemical system that includes the electrically conductive membrane, the salt water as an electrolyte and a stainless steel counter anode. The efficiency of the cleaning procedure in the flux recovery has been proved with typical bio- and inorganic membrane foulants such as CaCO3 and yeast suspensions. The cleaning mechanism during the electrolysis process is explained by the evolution of gases forming micro-bubbles at the membrane surface which remove the foulant material out from the membrane. The proposed method enables in situ membrane self-cleaning, thus providing a non-destructive, continuous and renewable approach for the mitigation of the different types of membrane fouling.