Photocatalytic inactivation of viruses using titanium dioxide nanoparticles and low-pressure UV light

The carcinogenic potential of chlorine disinfection by-products and recent changes in water quality regulations have led to a greater emphasis on alternative disinfection mechanisms. In this study, the efficacy of bench-scale and pilot-scale titanium dioxide (TiO2) photocatalytic disinfection was explored using four bacteriophages (MS2, PRD1, phi-X174, and fr). The optimized bench-scale experiments indicated that 1 mg/L of Degussa P25 TiO2 irradiated by low-pressure ultraviolet (UV) light reduced the dose requirements for viral inactivation in comparison to UV light alone. The highest UV dose reductions for 4-log inactivation of PRD1, MS2, phi-X174, and fr were 19%, 15%, 6%, and 0%, respectively. Bench-scale photocatalysis was inhibited by limited adsorption of the viruses onto the TiO2 nanoparticles, as indicated by the poor results for high TiO2 concentrations. Subsequently, pilot-scale experiments were completed using the Photo-Cat Lab from Purifics. The annular reactor configuration and increased viral adsorption dramatically improved photocatalytic inactivation for samples with high TiO2 concentrations. Using the Photo-Cat Lab, 2-log inactivation of the bacteriophages was achieved with 400 mg/L of Degussa P25 TiO2 and a UV dose of approximately 34 mJ/cm2 (energy consumption of 0.33 kWh/m3)—a 700-fold decrease in energy use compared to bench-scale photocatalysis.

[1]  M. Sela,et al.  Antiviral effect on MS-2 coliphage obtained with a synthetic antigen. , 1976, Proceedings of the National Academy of Sciences of the United States of America.

[2]  L. Locascio,et al.  Cleavage of peptides and proteins using light-generated radicals from titanium dioxide. , 2007, Analytical chemistry.

[3]  Martin A. A. Schoonen,et al.  Quantifying hydrogen peroxide in iron-containing solutions using leuco crystal violet , 2005, Geochemical transactions.

[4]  A. Sclafani,et al.  Comparison of the Photoelectronic and Photocatalytic Activities of Various Anatase and Rutile Forms of Titania in Pure Liquid Organic Phases and in Aqueous Solutions , 1996 .

[5]  H. Morowitz.  Absorption effects in volume irradiation of microorganisms. , 1950, Science.

[6]  Maria Vittoria Diamanti,et al.  Photocatalytic behavior of different titanium dioxide layers , 2007 .

[7]  T. Matsunaga,et al.  Continuous-sterilization system that uses photosemiconductor powders , 1988, Applied and environmental microbiology.

[8]  J. Crittenden,et al.  Destruction of DBP precursors with catalytic oxidation , 1995 .

[9]  J. Crittenden,et al.  Photocatalytic inactivation of Cryptosporidium parvum with TiO(2) and low-pressure ultraviolet irradiation. , 2008, Water research.

[10]  A. Cassano,et al.  ABSORPTION AND SCATTERING COEFFICIENTS OF TITANIUM DIOXIDE PARTICULATE SUSPENSIONS IN WATER , 1996 .

[11]  C. Gerba,et al.  Inactivation of Feline Calicivirus and Adenovirus Type 40 by UV Radiation , 2003, Applied and Environmental Microbiology.

[12]  Seockheon Lee,et al.  Inactivation of phage Qß by 254nm UV light and titanium dioxide photocatalyst , 1998 .

[13]  Karl G. Linden,et al.  Standardization of Methods for Fluence (UV Dose) Determination in Bench-Scale UV Experiments , 2003 .

[14]  Jeyong Yoon,et al.  Different Inactivation Behaviors of MS-2 Phage and Escherichia coli in TiO2 Photocatalytic Disinfection , 2005, Applied and Environmental Microbiology.

[15]  Michio Matsumura,et al.  Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases , 2001 .

[16]  L. Liljas,et al.  Crystal structure of bacteriophage fr capsids at 3.5 A resolution. , 1994, Journal of molecular biology.

[17]  D. Stuart,et al.  Insights into assembly from structural analysis of bacteriophage PRD1 , 2004, Nature.

[18]  M. Davies,et al.  EPR studies on the selectivity of hydroxyl radical attack on amino acids and peptides , 1998 .

[19]  W. Hijnen,et al.  Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: a review. , 2006, Water research.

[20]  Cesar Pulgarin,et al.  Field solar E-coli inactivation in the absence and presence of TiO2: is UV solar dose an appropriate parameter for standardization of water solar disinfection? , 2004 .

[21]  M. Rossmann,et al.  Analysis of the single-stranded DNA bacteriophage phi X174, refined at a resolution of 3.0 A. , 1994, Journal of molecular biology.

[22]  M. Sarvas,et al.  Probing the ability of the coat and vertex protein of the membrane-containing bacteriophage PRD1 to display a meningococcal epitope. , 2003, Virology.

[23]  E. Wimmer,et al.  Pyrite-induced hydroxyl radical formation and its effect on nucleic acids , 2006, Geochemical transactions.

[24]  Brooke K. Mayer,et al.  Efficacy of removal of CCL viruses under enhanced coagulation conditions. , 2007, Environmental science & technology.

[25]  M. Yates,et al.  Effect of adenovirus resistance on UV disinfection requirements: A report on the state of adenovirus science , 2006 .