Adsorption of bacteriophages on clay minerals

The ability to predict the fate of microorganisms in soil is dependent on an understanding of the process of their sorption on soil and subsurface materials. Presently, we have focused on studying the thermodynamics of sorption of bacteriophages (T-2, MS-2, and phi X-174) on clays (hectorite, saponite, kaolinite, acid clay fraction of samples collected from a landfill site). The thermodynamic study not only determines the feasibility of the process but also provides information on the relative magnitudes of the different forces under a particular set of conditions. The total free energy of interaction during sorption of bacteriophages on clays (Delta G) has been assumed to be the summation of Delta G(H) (Delta G due to hydrophobic interactions) and Delta G(EL) (Delta G due to electrostatic interactions). The magnitude of Delta G(H) was determined from the different interfacial tensions (gamma) present in the system, while Delta G(EL) was calculated from zeta-potentials of the colloidal particles. Calculated results show that surface hydrophobicities of the selected sorbents and sorbates dictate sorption. Among the selected bacteriophages, maximum sorption was observed with T-2, while hectorite has the maximum sorption capacity. Experimental results obtained from the batch adsorption studies also corroborated those obtained from the theoretical study.