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This paper deals with new fouling resistant RO membranes which are made morehydrophilic and less charged or charged with the same charge as the foulants to reduce hydrophobicinteraction and charge attraction or to increase charge repulsion, respectively. The fouling resistantmembranes were recently manufactured by Saehan Industries, Inc. in Korea via coating RO membraneswith hydrophilic monomers followed by polymerization and cross-linking reaction. The fouling resistantRO membranes showed much less flux reduction than the regular RO membrane when both membraneswere subjected to 30 ppm dry milk, 50 ppm a cationic surfactant, 50 ppm a nonionic surfactant and 50ppm humic acid, respectively.The coated membranes were characterized in terms of membrane surface charge (zeta potential) andhydrophobicity (contact angle). The coated membranes showed much less negative charge than theregular uncoated membrane, but the contact angle of the coated membrane was about the same as theregular membrane. The membrane surface charge was controlled using various coating compounds. Themembranes with various surface charges were dyed with a cationic dye such as methylene blue. Theintensity of dyeing was linearly correlated with the degree of the negative charge on the membranes. Theregular uncoated membrane was dyed the most since it has the most negative charge. The membranefouling by the cationic surfactant was also linearly correlated with the degree of the negative charge onthe membranes. The membrane fouling by the nonionic surfactant and humic acid had some relationwith hydrophobic interaction between the foulants and the membranes. The membrane fouling by thedry milk appeared to be influenced by a mixture of hydrophobic effect, charge effect and some colloidaldeposits.In a field test using 8040 elements, the fouling resistant membrane maintained much higher permeabilitythan the regular membrane when both are fed with an industry wastewater at Hyundai Motor Co. forabout 40 days. The fouling resistant RO membrane has been successfully in operation for treating wastewater at Samsung Electronics Co. for about five months. Includes 5 references, tables, figures.

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Edition: Vol. - No. Published: 03/05/2003 Number of Pages: 10File Size: 1 file , 280 KB