Photocatalytic inactivation of Cryptosporidium parvum with TiO(2) and low-pressure ultraviolet irradiation

Water Res. 2008 Mar;42(6-7):1523-30. doi: 10.1016/j.watres.2007.10.037. Epub 2007 Nov 4.


This study investigated the efficacy of low-pressure ultraviolet (UV) irradiation and the synergistic effect of UV/titanium dioxide (TiO(2)) photocatalysis on Cryptosporidium parvum oocyst inactivation. At UV doses of 2.7, 8.0, and 40mJ/cm(2), oocyst inactivation was 1.3, 2.6, and 3.3log(10), respectively. Reactive oxygen species (ROS) generated by longwave UV radiation (>315nm) and TiO(2) achieved less than 0.28-log inactivation. However, the synergistic effect of germicidal (254nm) UV and TiO(2) resulted in 2-log and 3-log oocyst inactivation with 4.0 and 11.0mJ/cm(2), respectively. Therefore, using TiO(2) in combination with UV reduced the dose requirement for 3-log inactivation by 56%. An approximate 1-log decrease in inactivation of oocysts was observed with nanopure water in comparison to buffered water, whereas changes in pH from 6 to 8 had little effect on the photocatalytic inactivation of oocysts in either matrix (P>0.1).

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Catalysis
  • Cell Line, Tumor
  • Cryptosporidium parvum / drug effects*
  • Cryptosporidium parvum / radiation effects*
  • Humans
  • Photochemistry
  • Titanium / pharmacology*
  • Ultraviolet Rays*


  • titanium dioxide
  • Titanium