Application of surface modified polypropylene membranes to an anaerobic membrane bioreactor

In order to increase hydrophilicity and thereby to reduce membrane fouling caused by hydrophobic adsorption, the surface of a hydrophobic 0.2 mum poly propylene (PP) membrane was modified by ozone treatment followed by graft p olymerization with 2-hydroxy-ethyl methacrylate (HEMA). The modified PP (MP P) membranes were characterized in terms of contact angle, morphology and d egree of grafting (DG). The contact angle was reduced from 112 degrees for a PP membrane to nearly 0 degrees for MPP membranes by introducing function al groups such as hydroxyl (-OH) and carbonyl groups (C=O) on the membrane surface. As the DG increased, the O/C ratio and membrane resistance of the MPP membrane increased. Using the MPP membrane in the crossflow operation o f an anaerobic membrane bioreactor (MBR), the membrane permeability was enh anced although it was largely dependent on the DG of MPP.