Investigating the Effect of Various Oxidizing Agents on the Surface Functionalization of Microporous Polypropylene Membranes

Wet chemical functionalization is an easy and efficient method, which connects the polar functional groups to the surface of polymeric membranes. In this work, KClO3, K2Cr2O7 and KMnO4 were dissolved in sulfuric acid and used to functionalize microporous polypropylene (PP) membranes, fabricated via thermally induced phase separation (TIPS) method. The optimum concentration of oxidizing agents and sulfuric acid as well as the membrane immersion time in oxidizing solutions were determined. The percentage of re-construction phenomenon was about 3.1%, 24% and 34.7% for PP membrane treated by KClO3, K2C2O7 and KMnO4, respectively. The results showed that the absorbance intensities of -OH and C=O peaks as well as the variety of functional groups in the samples treated by KClO3 are remarkably higher than that of the samples treated by K2Cr2O7 and KMnO4. BSA filtration experiments revealed that the total fouling ratio (TFR) and irreversible fouling ratio (IFR) decreased from 75% and 63.6% for pristine membrane to 50.3%, 53.4%, 55.6% and 27.6%, 27.6%, 27.3% for modified membranes by KClO3, K2Cr2O7 and KMnO4, respectively. The flux recovery (FR) of treated membranes was about twice higher than that of the nascent membrane. The results indicated that incorporation of hydrophilic functional groups on the surface of PP membranes improves the fouling resistance behavior.