Removal of bacteriophages MS2 and phiX174 from aqueous solutions using a red soil

Adsorption and desorption of viruses onto and from an adsorbent may have a dominant role in evaluating removal efficiency of a material. This study evaluated the effectiveness of a red soil from south part of China to remove two viruses, MS2 and phiX174, by adsorption from dilute aqueous solutions using a set of equilibrium and kinetic batch experiments. The effect of presence/absence of autochthonous microorganisms was also investigated. The results showed that when the autochthonous microorganisms were present, the red soil adsorbed more than 99.95% of MS2 and 98.23% of phiX174, in which most of them were inactivated and/or irreversibly adsorbed. Sterilization led to an increase in MS2 adsorption, while decreased the adsorption of phiX174, indicating that sterilization-induced virus adsorption is virus type dependent. Fewer viruses could be desorbed from the sterilized soil as compared to the nonsterilized soil, probably because sterilization led to an increase in the strength of adsorption force between the soil and viruses. Though the overall virus removal efficiency by the red soil was less than the USPEA required value of 99.99%, we suggest the potential of the red soil as a starting material in removing water heavily polluted with viruses.