Search

Low-fouling polyvinylidene fluoride microfiltration membranes were first developed by grafting a carboxybetaine polymer (PCMB) onto the surface and pore walls. Two grafting procedures were investigated. One was atom transfer radical polymerization (ATRP), and the other was activator generated by electron transfer ATRP (AGET-ATRP). In both methods, the Fenton reaction followed by the initiator immobilization was carried out prior to ATRP or AGET-ATRP. Although there was a difference in the grafting rate, it was possible to control the grafting amount by governing the grafting time in both methods. The grafting of PCMB had two opposite effects on the performance of the membrane: it increased its low-fouling property and decreased its pure water permeability. Pure water permeability measurements and filtration tests using aqueous solution containing BSA revealed that the optimum grafting amount that achieved excellent low-fouling while retaining high pure water permeability was 0.17–0.2 mg cm–2. We also investigated cleaning the fouled membrane with a sodium hydroxide solution at pH 11. The treated membrane indicated the recovery of pure water permeability and the preservation of the low-fouling property.