It has been reported that surface modification with polydopamine -PDA- increases the hydrophilicity and the negative charge density of membrane surfaces, which improves their antifouling potential against organic foulants. Thus, in this paper, we attempted to modify a reverse osmosis -RO- membrane with PDA to improve antibiofouling potential. The deposition of PDA was confirmed by several methods, including X-ray photoelectron and Fourier-transform infrared spectroscopy. However, increases in hydrophilicity and negative charge density were not clearly observed. Nevertheless, the improvement of antibiofouling properties was confirmed by cross-flow filtration of a bacterial -Pseudomonas putida- suspension. The high antiadhesion property of the PDA-modified membrane was confirmed by scanning electron microscope surface images after 1200 minute continuous filtration of the bacterial suspension. In addition, it was confirmed by using a shake flask test with Escherichia coli that the PDA-modified membrane had a bactericidal property. Using shake flask tests in the different pH solutions, it was concluded that the antibiofouling property of PDA-modified membranes could be attributed to the bactericidal property of protonated amine groups of PDA deposited on the membrane surface.

Keywords