Journal of Water Supply: Research and Technology—AQUA Vol 55 No 7-8 pp 461–470 © IWA Publishing 2006 doi:10.2166/aqua.2006.056
Zeta potential distributions in particle treatment processes
Jinkeun Kim, Jeffrey A. Nason and Desmond F. Lawler
Department of Civil, Architectural and Environmental Engineering, C1786, University of Texas at Austin, Austin, TX 78712, USA e-mail: dlawler@mail.utexas.edu
Present address: Water Resources Academy, Korea Water Resources Corporation, Daejeon, 306–711, Korea
ABSTRACT
Most experimental studies of particle destabilization prior to flocculation and granular media filtration characterize the surface charge of particles using the observed average zeta potential. A more complete accounting of particle–particle and particle–collector interactions can be deduced from analyzing the complete distribution of particle zeta potentials. Zeta potential distributions (ZPDs) of silica particles under chemical conditions reflective of destabilization by pH control, ionic strength adjustment, alum destabilization, and polymer destabilization were investigated. Most of the ZPDs of silica particles were broad and skewed (i.e. not normally distributed). When particle surface charge is controlled by pH control, ionic strength adjustment, and alum destabilization, the variances of the ZPDs are comparable. However, when a high-charge-density polymer is utilized as the coagulant, under-dosed and optimally dosed systems result in ZPDs that are broad and over-dosed systems result in narrow distributions.
Keywords: electrophoretic mobility; filtration; flocculation; particles; zeta potential
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