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PHYSICOCHEMICAL INTERACTION OF ESCHERICHIA COLI CELL ENVELOPES AND BACILLUS SUBTILIS CELL WALLS WITH TWO CLAYS AND ABILITY OF THE COMPOSITE TO IMMOBILIZE HEAVY METALS FROM SOLUTION
Citation:
Walker, S., C. Flemming, F. Ferris, T. Beveridgel, AND G. Bailey. PHYSICOCHEMICAL INTERACTION OF ESCHERICHIA COLI CELL ENVELOPES AND BACILLUS SUBTILIS CELL WALLS WITH TWO CLAYS AND ABILITY OF THE COMPOSITE TO IMMOBILIZE HEAVY METALS FROM SOLUTION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/251 (NTIS PB90135500), 1989.
Description:
Isolated Escherichia coli K-l2 cell envelopes or Bacillus subtilis 168 cell walls were reacted with smectite or kaolinite clay in distilled deionized water (pH 6.0); unbound envelopes or walls were separated by sucrose density gradient centrifugation, and the extent of adsorption was calculated. t saturation, both clays adsorbed approximately 1.0 mg(dry weight) of envelopes or walls per mg (dry weight) of clay. lays showed a preference for edge-on orientation with both walls and envelopes, which was indicative of an aluminum polynuclear bridging mechanism between the wall or envelope surface and the clay edge. he addition of heavy metals increased the incidence of planar surface orientations, which suggested that multivalent metal cation bridging was coming into play and was of increasing importance. n a dry-weight basis, the envelope-clay and wall-clay mixtures bound 20 to 90% less metal than equal amounts of the individual components did. his reduction in metal-binding capacity indicates that the adsorption of the wall or envelope to clay has masked or neutralized chemically reactive adsorption sites normally available to metal ions. ransmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed these results and gave high spatial resolution to the regions of high binding density.
