Influence of Salts on Virus Adsorption to Microporous Filters

ABSTRACT We investigated the direct and indirect effects of mono-, di-, and trivalent salts (NaCl, MgCl2, and AlCl3) on the adsorption of several viruses (MS2, PRD-1, φX174, and poliovirus 1) to microporous filters at different pH values. The filters studied included Millipore HA (nitrocellulose), Filterite (fiberglass), Whatman (cellulose), and 1MDS (charged-modified fiber) filters. Each of these filters except the Whatman cellulose filters has been used in virus removal and recovery procedures. The direct effects of added salts were considered to be the effects associated with the presence of the soluble salts. The indirect effects of the added salts were considered to be (i) changes in the pH values of solutions and (ii) the formation of insoluble precipitates that could adsorb viruses and be removed by filtration. When direct effects alone were considered, the salts used in this study promoted virus adsorption, interfered with virus adsorption, or had little or no effect on virus adsorption, depending on the filter, the virus, and the salt. Although we were able to confirm previous reports that the addition of aluminum chloride to water enhances virus adsorption to microporous filters, we found that the enhanced adsorption was associated with indirect effects rather than direct effects. The increase in viral adsorption observed when aluminum chloride was added to water was related to the decrease in the pH of the water. Similar results could be obtained by adding HCl. The increased adsorption of viruses in water at pH 7 following addition of aluminum chloride was probably due to flocculation of aluminum, since removal of flocs by filtration greatly reduced the enhancement observed. The only direct effect of aluminum chloride on virus adsorption that we observed was interference with adsorption to microporous filters. Under conditions under which hydrophobic interactions were minimal, aluminum chloride interfered with virus adsorption to Millipore, Filterite, and 1MDS filters. In most cases, less than 10% of the viruses adsorbed to filters in the presence of a multivalent salt and a compound that interfered with hydrophobic interactions (0.1% Tween 80 or 4 M urea).

[1]  M. Sobsey,et al.  Poliovirus concentration from tap water with electropositive adsorbent filters , 1980, Applied and environmental microbiology.

[2]  K. Stana-Kleinschek,et al.  Electrokinetic properties of processed cellulose fibers , 1998 .

[3]  C. Gerba,et al.  Concentration of poliovirus from tap water onto membrane filters with aluminum chloride at ambient pH levels , 1978, Applied and environmental microbiology.

[4]  C. Gerba,et al.  Methods for concentrating viruses from large volumes of estuarine water on pleated membranes , 1976 .

[5]  J. Morel,et al.  Novel approach for modifying microporous filters for virus concentration from water , 1988, Applied and environmental microbiology.

[6]  S. Farrah.  Chemical factors influencing adsorption of bacteriophage MS2 to membrane filters , 1982, Applied and environmental microbiology.

[7]  S. Farrah,et al.  Influence of salts on electrostatic interactions between poliovirus and membrane filters , 1983, Applied and environmental microbiology.

[8]  L. Ingram,et al.  Effects of chaotropic and antichaotropic agents on elution of poliovirus adsorbed on membrane filters. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[9]  C. Gerba,et al.  Concentration of viruses from large volumes of tap water using pleated membrane filters , 1976, Applied and environmental microbiology.

[10]  G. Bitton,et al.  Elution of poliovirus adsorbed to membrane filters , 1978, Applied and environmental microbiology.

[11]  Neil Blumberg,et al.  Genetics Experiments with Bacterial Viruses , 1972, The Yale Journal of Biology and Medicine.

[12]  C. Gerba,et al.  Concentration of viruses from water by membrane chromatography. , 1979, Annual review of microbiology.

[13]  C. Wallis,et al.  Enterovirus concentration on cellulose membranes. , 1972, Applied microbiology.

[14]  M. Myers,et al.  Virus Passage through Track-Etch Membranes Modified by Salinity and a Nonionic Surfactant , 1999, Applied and Environmental Microbiology.

[15]  M. A. Kessick,et al.  Electrophoretic mobilities of virus adsorbing filter materials , 1978 .

[16]  C. Gerba.  Applied and theoretical aspects of virus adsorption to surfaces. , 1984, Advances in applied microbiology.

[17]  C. Gerba,et al.  Methods in environmental virology , 1982 .

[18]  G. Berg.  Methods For Recovering Viruses From The Environment , 1987 .

[19]  C. Gerba,et al.  Characteristics of humic acid and organic compounds concentrated from tapwater using the aquella virus concentrator , 1976 .

[20]  Awwa,et al.  Standard Methods for the examination of water and wastewater , 1999 .

[21]  S. Farrah,et al.  Concentration of viruses from water by using cellulose filters modified by in situ precipitation of ferric and aluminum hydroxides , 1985, Applied and environmental microbiology.

[22]  M. Sobsey,et al.  Influence of water quality on enteric virus concentration by microporous filter methods , 1984, Applied and environmental microbiology.

[23]  D. Shah,et al.  Comparison of positively charged membrane filters and their use in concentrating bacteriophages in water , 1986 .