Evaluation of Porous Carbon Adsorbents Made from Rice Husks for Virus Removal in Water

Porous carbons are well-known efficient adsorbents for a variety of organic and inorganic pollutants; however, they have difficulty in virus removal. In this study, novel porous carbons (NPCs) (NPC-A, NPC-B, and NPC-C) derived from rice husks were compared with commercially available activated carbons (ACs) for their ability to remove MS2 bacteriophages (MS2) in a batch experiment. NPC-A was produced by the silica removal process. NPC-B was prepared with an additional steam activation applied to NPC-A. NPC-C was obtained with an additional acid rinse applied to NPC-B. The NPCs (particularly NPC-C) exhibited effective removal of up to 5.3 log(10) of MS2, which was greater than that of less than 2.7 log(10) obtained by other ACs under 10 g/L during the same contact time (60 min). The pore size distribution of the porous carbon adsorbents was found to influence their virus removal performance. The adsorbents with a larger proportion of pores ranging from 200-4500 nm in diameter were able to achieve higher virus removal rates. Thus, NPCs (particularly NPC-C), which had a larger volume of pores ranging from 200-4500 nm in size, demonstrated the potential for use as efficient adsorbents for removing viruses during water purification.