Adsorptive property of Cu 2+-loaded montmorillonite clays for Escherichia coli K 88in vitro

Abstract

The adsorption properties of Cu 2+-loaded montmorillonite clays (MMT-Cu) for Escherichia coli K 88 as a function of time, bacteria concentrations, pH, ionic strength and temperature were investigated. The results showed that the bacteria adsorption onto MMT-Cu surface reached equilibrium after 90 min. The percentages of E. coli K 88 adsorbed onto the surfaces of MMT-Cu and montmorillonite clays (MMT) at equilibrium were 88.9% and 56.5%, respectively. Scanning electron microscopy revealed that a lot of E. coli K 88 adhered to the surface of MMT-Cu. The zeta potential of MMT-Cu was relatively high as compared to that of MMT. The adsorptive ability of MMT-Cu for E. coli K 88 was higher than that of MMT ( P < 0.05). Moreover, pH, ionic strength and temperature produced a strong influence on the extent of E. coli K 88 adsorption to surface of MMT-Cu and MMT. The mechanism of adsorption of E. coli onto MMT-Cu may involve electrostatic attraction and physiochemical properties of bacterial cell walls and minerals surfaces.