Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
634088 | Journal of Membrane Science | 2013 | 9 Pages |
Abstract
Monitoring the 'state of the process' is particularly useful in fouling control in the reverse osmosis (RO) industry. In this paper, a novel non-invasive method to monitor the fouling process of single and binary foulants on the RO membrane has been studied; that of electrical impedance spectroscopy (EIS). A typical RO crossflow cell was equipped with electrodes to allow in-situ EIS measurement of the fouling process during RO filtration. The EIS signals were converted to Nyquist plots of the negative imaginary impedance versus the real impedance, and used as a convenient means for characterization of fouling. Different forms of the Nyquist plot were obtained for different types of foulant. Also a significant shift in the Nyquist plots for silica, BSA and their mixtures occurred corresponding to the buildup of a foulant layer on the membrane surface. During the early stages of fouling, the Nyquist plots shifted noticeably while the transmembrane pressure (TMP) showed negligible increase. If EIS could perform on-line in plant operation, it could be a sensitive monitoring tool to detect early fouling in RO membrane filtration.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
L.N. Sim, Z.J. Wang, J. Gu, H.G.L. Coster, A.G. Fane,