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Environmental Engineering Research 1998;3(2): 97-104.
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Surface Charge Effects on Particulate Retention by Microporous Membrane Filters in Liquid Filtration |
Jae-Keun Lee† |
School of Mechanical Engineering Research Institute of Mechanical Engineering Pusan National University, Pusan, 609-735, Korea |
Corresponding Author:
Jae-Keun Lee , |
Received: March 6, 1998; Accepted: May 6, 1998. |
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ABSTRACT |
Surface charge effects in particulate retention by microporous membrane filters have been investigated by measuring the zeta potential of the particles and filters, and the particle retention characteristics of the membrane using a liquid-bome laser particle counter and latex spheres. Particle retention tests were conducted with 0.45μm rated polyvinylidence difluoride(PVDF) membrane filters and latex spheres ranging in diameters from 0.1 to 0.741μm. Both negatively and positively charged particles and filters were used. The measured zeta potential values of latex spheres, silicon, and alumina particles in deionized (DI) water were found to be -40.5, -26.0 and -10-lmV, respectively. The zeta potential of latex spheres was always negative and was found to be nearly constant, at -35 mV, over the entire pH range. For the negatively charged, 0.45μm rated filter, retention of the negatively charged 0.204μm diameter spheres was found to be 74%. Particle retention of negatively charged 0.193»m latex particles by a positively charged, 0.45μm rated filter media was )99.99999%, due to the combination of electrostatic adsorption with mechanical sieving. The experimental study showed that colloidal particles have been attracted to the pore surface of the filters due to electrokinetic adsorption, if the filter and the contaminant are oppositely charged. |
Keywords:
liquid filtration | membrane filter | zeta potential | electrophoresis | sieving | electrostatic adsorption | pore size |
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