Measuring the Surface Zeta Potential of Nanofilters for Viral and Bacterial Filtration

The DelsaNano​ series is a new generation of instruments that use photon correlation spectroscopy (PCS), which determines particle size by measuring the rate of fluctuations in laser light intensity scattered by particles as they diffuse through a fluid, for size analysis measurements and/or electrophoretic light scattering (ELS), which determines electrophoretic movement of charged particles under an applied electric field from the Doppler shift of scattered light, for zeta potential determination.

This series has a broad range of capabilities, including conventional static and automatic titration measurements for both size and zeta potential distributions of suspended particles in a wide range of size and concentration. The DelsaNano also can measure zeta potential of a solid surface or film.

Comparison of Nanofilters with Ultraporous Filters

Recent progress in nanotechnology has enabled the development of a filter material capable of removing viruses and bacteria more efficiently than conventional ultraporous filters, and capable of maintaining a high filtration rate.

Applications of Nanofilters in Viral and Bacterial Filtration

Applications of this filter include: 1. Selective filtration of mixed aqueous solutions 2. Removal of microorganisms (from drinking water and other drinks, blood serum, biologics, etc.) 3. Filtration of DNA, RNA, endotoxins, etc. 4. Separation and extraction of nucleic acids and proteins.

Determination of Surface Potentials of Different Materials Used in Filters

In this study, the flat surface cell of Beckman Coulter DelsaNano​ C was used to determine surface zeta potentials of filters (A, B, C, D) made of different materials before and after filtration of organic matter to obtain purified water. The surface zeta potential of filters before and after the filtration are shown in Fig. 1. Although it depended on the material, the surface zeta potentials of the filters before use were about -60 to -120 mV. The surface zeta potentials of the respective filters after filtration of organic matter were about -40 mV. This value (-40 mV) is believed to be the zeta potential of the organic matter. This study shows that surface zeta potential determination using the flat surface cell can be applicable to the evaluation of functional membranes.

Surface zeta potentials before and after filtration.

Figure 1. Surface zeta potentials before and after filtration.
Surface zeta potentials before and after filtration.

This information has been sourced, reviewed and adapted from materials provided by Beckman Coulter, Inc. - Particle Characterization.

For more information on this source, please visit Beckman Coulter, Inc. - Particle Size Characterization.

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