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  1.  Pure-Light Study #1: Barley Sprouts and mold  November 2017

• Conducted by: Sustainable Lighting Solutions Christopher Rakowitz & Ken Chio

• The purpose of this experiment was to determine the effectiveness of the Pure Light coating using photocatalytic activation specifically to control mold and yeast on barley sprouts.

• Conclusion:  Pure-Light not only dramatically reduced the heavily introduced mold, but doubled the growth of the Barley sprouts. 

"The photocatalytic technique appears to be a versatile and efficient disinfection process capable of inactivating a wide range of harmful microorganisms in various media. It is a safe, nontoxic, and relatively inexpensive disinfection method whose adaptability allows it to be used for many purposes. Mold levels are very significantly reduced under very difficult conditions not normally seen in horticulture. Typical conditions would not promote mold before and during a cultivation period and therefore would never reach levels of mold found in our testing. Under normal conditions, it would be expected from our test results that mold levels would very easily be controlled by use of the Pure-Light coating."

2. Pure Light Study #2: Pure-Light Bulbs (only) Effectiveness against E-Coli, Salmonella, and MRSA. February 2018. 

• "Glass slide and laminated wood flooring coupons were inoculated in triplicate with a suspension of Escherichia coli, Salmonella enterica, and methicillin-resistant Staphylococcus aureus (MRSA). The slides and wood flooring samples were exposed to PURE-LIGHT coated LED light bulbs and tested at 24 and 72 hour intervals to determine organism survival/reduction. Control slides and coupons (not exposed to light bulbs) were also tested at 24 hour and 72 hour intervals for comparison purposes. The glass slide coupons were set on a counter approximately 5 feet from the surface of the lights. The wood flooring coupons were set on the floor of the room approximately 8 feet from the lights."

"The greatest bacterial reduction was seen after 72 hours of treatment compared to 24 hours. E. coli was reduced by 94.7% on glass and 93.3% on the wood surface after 72 hours of treatment. MRSA was reduced by 80.6% and 80.0% on glass and wood after 72 hours. S. enterica was also reduced but by a smaller degree; 47.3% on glass and 57.4% on wood after 72 hours of treatment."

....click here for full study in pdf format... ​
3.  Pure-Light Study #3: Pure-Light Bulbs + Pure-Light Sani-Light Coating against Salmonella, E-Coli, MRSA

Glass slides coated with PURE-LIGHT SANI-LIGHT® solution were inoculated in triplicate with a suspension of Escherichia coli, Salmonella enterica, and Methicillin-resistant Staphylococcus Aureus. One group of slides was exposed to PURE-LIGHT coated LED light bulbs at counter and floor levels and another group was not exposed to the light also at counter and floor levels. All slides were tested after 24 hours to determine organism survival.

Bacterial reduction of Salmonella and MRSA inoculated onto the surfaces of PURE-LIGHT SANI-LIGHT® coated slides ranged from 97 to 99.9% when compared to the same organisms inoculated at the same levels onto uncoated slides and exposed to the same conditions. The greatest reduction was observed in the organism average of the slide group exposed to the PURE-LIGHT LED light bulbs at counter height (about 5 feet below light bulbs) while the least reduction was observed in the organism average of the slide group not exposed to the PURE-LIGHT LED light bulbs at Floor level. Reduction of E. coli could not be accurately determined as the recovery of the uncoated control slides at 24 hours was below detection limits. It appears the survivability of E. coli  after 24 hours was very low regardless of the slide type the organism was inoculated on.

Click here for the full study
Studies pertaining to titanium dioxide Nano particles

Compared to Chlorine disinfection, Ozonation, irradiation using germicidal lamps which all have problems, the TiO2 photocatalytic process is Nontoxic, chemically stable, safe, nonhaxardous and ecofriendly.
Applications of Photocatalytic Disinfection - Hindawi


Applications of photocatalytic processes are widely recognized as viable solutions to environmental problems [13]. Disinfection of bacteria is of particular importance, because traditional methods such as chlorination are chemical intensive and have many associated disadvantages. For example, in water treatment applications, chlorine used for disinfection can react with organic material to generate chloro-organic compounds that are highly carcinogenic [45]. Furthermore, some pathogens such as viruses, certain bacteria such as Legionella, and protozoans such as Cryptosporidium and Giardia lamblia cysts have been known to be resistant to chlorine disinfection [67]. Other treatment alternatives such as ozonation and irradiation using germicidal lamps (254 nm) have their own problems and limitations, such as the lack of residual effect [8] and generation of small colony variants [9] for the latter and production of toxic disinfection byproducts for the former [10].

In comparison, the  semiconductor commonly used in photocatalytic processes is nontoxic, chemically stable, available at a reasonable cost, and capable of repeated use without substantial loss of catalytic ability [11]. Heterogeneous photocatalysis using titanium dioxide is a safe, nonhazardous, and ecofriendly process which does not produce any harmful byproducts. Extensive research in this field has been done in the area of photocatalytic removal of organic, inorganic, and microbial pollutants [1213].

International Journal of Photoenergy Volume 2010 (2010), Article ID 764870, 11 pages
Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

Develop Methods To Assess And Improve Poultry And Egg Quality

Interpretive Summary: Salmonella and Listeria are commonly detected in both raw and ready-to-eat meat products, and are responsible for many outbreaks of foodborne diseases in the USA. Nano-TiO2 has been demonstrate to be very effective to inhibit microbial growth under UV light, and is considered as a novel material that can be used for eliminating microbial pathogens from food. The objective of this study was to investigate the antimicrobial effects of nano-TiO2 particles on bacterial pathogens, Salmonella typhimurium and Listeria Monocytogenes, which are commonly found on raw and/or cooked poultry meat products. Our results show that nano-TiO2 effectively reduced the populations of either of the pathogens under UV light. Its effectiveness could be affected by nano-TiO2 concentrations and the initial microbial populations. L. monocytogenes was more resistant to nano-TiO2 treatment than Salmonella. Electronic microscopic images showed that under UV light, nano-TiO2 resulted in damage of bacterial cell walls, release of cell components, and subsequently the cell death. These results demonstrate that we can use nano-TiO2 to treat food products and reduce the risk of foodborne diseases by reducing pathogen populations and/or inhibiting pathogen growth.

Studies of photokilling of bacteria using titanium dioxide nanoparticles

Metal pins used to apply skeletal traction or external fixation devices protruding through skin are susceptible to the increased incidence of pin site infection. In this work, we tried to establish the photokilling effects of titanium dioxide (TiO2) nanoparticles on an orthopedic implant with an in vitro study. In these photocatalytic experiments, aqueous TiO2 was added to the tested microorganism. The time effect of TiO2 photoactivation was evaluated, and the loss of viability of five different bacteria suspensions (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus hirae, and Bacteroides fragilis) was examined by the viable count procedure. The bactericidal effect of TiO2 nanoparticle-coated metal plates was also tested. The ultraviolet (UV) dosage used in this experiment did not affect the viability of bacteria, and all bacteria survived well in the absence of TiO2 nanoparticles. The survival curve of microorganisms in the presence of TiO2 nanoparticles showed that nearly complete killing was achieved after 50 min of UV illumination. The formation of bacterial colonies above the TiO2 nanoparticle-coated metal plates also decreased significantly. In this study, we clearly demonstrated the bactericidal effects of titanium dioxide nanoparticles. In the presence of UV light, the titanium dioxide nanoparticles can be applicable to medical facilities where the potential for infection should be controlled.

Technology For Growing Plants In Space Leads To Device That Destroys Pathogens, Like Anthrax

Building miniature greenhouses for experiments on the International Space Station has led to the invention of a device that annihilates anthrax -- a bacteria that can be deadly when inhaled.
"Space-based greenhouses may seem to have little to do with the war against terrorism," said Mark Nall, director of the Space Product Development Program at NASA's Marshall Space Flight Center in Huntsville, Ala. "Yet this invention shows how commercial space research can benefit people on Earth in unexpected ways."
The anthrax-killing air scrubber, AiroCide Ti02, is a tabletop-size metal box that bolts to office ceilings or walls. Its fans draw in airborne spores and airflow forces them through a maze of tubes. Inside, hydroxyl radicals (OH-) attack and kill pathogens. Most remaining spores are destroyed by high-energy ultraviolet photons.
"Spores that pass through the box aren't filtered -- they're fried," said John Hayman, president of KES Science & Technology Inc., the Kennesaw, Ga.-company that manufactures AiroCide Ti02. "That's appealing because you don't have to change an anthrax-laden air filter."
The technology to build the anthrax killer emerged from another product, Bio-KES, which is used by grocers and florists to remove ethylene and thus extend the life of vegetables, fruits and flowers. Ethylene (C2H4) is a gas released by the leaves of growing plants -- but too much of it can build up in an enclosed plant growth chamber or produce storage facility.
Too much ethylene causes plants to mature too quickly, fruit to ripen prematurely, and it even accelerates decay. This hinders researchers' efforts to harvest healthy plants grown in space and would also be undesirable when space travelers build larger space-based greenhouses for growing fresh food.
The research that led to the invention of Bio-KES started with a crucial discovery made in the early 90's by scientists at the Wisconsin Center for Space Automation and Robotics - a NASA Commercial Space Center at the University of Wisconsin-Madison. These scientists collaborated on the discovery with Dr. Marc Anderson, a professor and chemist who also works at the university.
The research team found that ultra-thin layers of titanium dioxide (TiO2) exposed to ultraviolet light converted ethylene into carbon dioxide (CO2) and water (H2O) -- substances that are good for plants. Subsequently, they developed a coating technology that applies TiO2 layers to the surfaces of many materials.

UCL scientists develop novel approaches for killing MRSA and E.coli
Dr Sean Nair, Michael Wilson
New research from the UCL Eastman Dental Institute and UCL Chemistry, presented at the spring conference of the Society for General Microbiology (SGM), has provided a potential drug for MRSA treatment and a new antibacterial coating using Titanium Dioxide which will help fight hospital-acquired infections.
Research from the UCL Eastman Dental Institute has resulted in the development of a light-activated drug that could be used in the treatment of infections caused by the hospital bug MRSA.  Researchers attached an antimicrobial drug, which is activated by light, to a peptide (a protein fragment) that binds onto a molecule on the surface of the superbug bacteria. Such light-activated antimicrobial agents produce free radicals and an unstable form of oxygen when they are exposed to light at the right wavelength. The release of these free radicals damages and ultimately kills bacteria.   99.97% of 10 million MRSA cells were killed using this new combination, which was 1,000 times more effective at killing MRSA compared to the commercially available SnCe6 when the same quantity is used. 

UCL scientists develop Light-activated antibacterial coating against hospital-acquired infections

Ivan Parkin, Dr Charles Dunnill, Michael Wilson, Dr Jonathan Pratten, and Zoie  Aiken from the UCL Eastman Dental Institute have  developed a hard coating with antibacterial properties that has been shown to kill 99.9% of 10 million Escherichia coli (E.coli) bacteria when a white hospital light was shone on its surface.  The veneer-like surface is made of titanium dioxide with added nitrogen. When it is activated by white light, similar to those used in hospital wards and operating theatres, it produces a decrease in the number of bacteria surviving on the test surface.  The hospital environment acts as a reservoir for the microbes responsible for healthcare-associated infections (HCAI) and new ways of preventing the spread of these pathogens to patients are needed. Antibacterial coatings could be applied to frequently touched hospital surfaces to kill any bacteria present and help reduce the number of HCAI. Titanium dioxide based coatings are known to kill bacteria after activation with UV light. The addition of nitrogen to these coatings enables photons (the basic unit of light) available in visible light to be utilised to activate the surface and kill bacteria.

Bactericidal activity of photocatalytic TiO2 reaction: toward an understanding of its killing mechanism

PC Maness, S Smolinski, DM Blake… - Applied and …, 1999 - Am Soc Microbiol
When titanium dioxide (TiO2) is irradiated with near-UV light, this semiconductor exhibits strong bactericidal activity. In this paper, we present the first evidence that the lipid peroxidation reaction is the underlying mechanism of death of Escherichia coli K-12 cells that are irradiated in the presence of the TiO2 photocatalyst. Using production of malondialdehyde (MDA) as an index to assess cell membrane damage by lipid peroxidation, we observed that there was an exponential increase in the production of MDA, whose concentration reached 1.1 to 2.4 nmol z mg (dry weight) of cells21 after 30 min of illumination, and that the kinetics of this process paralleled cell death. Under these conditions, concomitant losses of 77 to 93% of the cell respiratory activity were also detected, as measured by both oxygen uptake and reduction of 2,3,5-triphenyltetrazolium chloride from succinate as the electron donor. The occurrence of lipid peroxidation and the simultaneous losses of both membrane-dependent respiratory activity and cell viability depended strictly on the presence of both light and TiO2. We concluded that TiO2 photocatalysis promoted peroxidation of the polyunsaturated phospholipid component of the lipid membrane initially and induced major disorder in the E. coli cell membrane. Subsequently, essential functions that rely on intact cell membrane architecture, such as respiratory activity, were lost, and cell death was inevitable.

Bactericidal mode of titanium dioxide photocatalysis

Z Huang, PC Maness, DM Blake, EJ Wolfrum… - … of Photochemistry and …, 2000 - Elsevier
When exposed to near-UV light, titanium dioxide (TiO2) exhibits a strong bactericidal activity. However, the killing mechanism(s) underlying the TiO2 photocatalytic reaction is not yet well understood. The aim of the present study is to investigate the cellular damage sites and their contribution to cell death. A sensitive approach using o-nitrophenol β-d–galactopyranosideside (ONPG) as the probe and Escherichia coli as model cells has been developed. This approach is used to illustrate damages to both the cell envelope and intracellular components caused by TiO2 photocatalytic reaction. Treatment of E. coli with TiO2 and near-UV light resulted in an immediate increase in permeability to small molecules such as ONPG, and the leakage of large molecules such as β-d–galactosidase after 20 min. Kinetic data showed that cell wall damage took place in less than 20 min, followed by a progressive damage of cytoplasmic membrane and intracellular components. The results from the ONPG assay correlated well with the loss of cell viability. Cell wall damage followed by cytoplasmic membrane damage leading to a direct intracellular attack has therefore been proposed as the sequence of events when microorganisms undergo TiO2photocatalytic attack. It has been found that smaller TiO2 particles cause quicker intracellular damage. Evidence has been obtained that indicated that the TiO2photocatalytic reaction results in continued bactericidal activity after the UV illumination terminates.

Titanium Dioxide: Toxic or Safe?

Titanium dioxide is the subject of new controversy, yet it is a substance as old as the earth itself. It is one of the top fifty chemicals produced worldwide. It is a white, opaque and naturally- occurring mineral found in two main forms: rutile and anatase. Both forms contain pure titanium dioxide that is bound to impurities. Titanium dioxide is chemically processed to remove these impurities, leaving the pure, white pigment available for use. Titanium dioxide has a variety of uses, as it is odorless and absorbent. This mineral can be found in many products, ranging from paint to food to cosmetics. In cosmetics, it serves several purposes. It is a white pigment, an opacifier and a sunscreen. Concern has arisen from studies that have pointed to titanium dioxide as a carcinogen and photocatalyst, thus creating fear in consumers. But are these claims true? What does the research on these allegations bear out? Would we as consumers benefit from avoiding this mineral to preserve our long-term health?

A carcinogen is a substance that causes a cellular malfunction, causing the cell to become cancerous and thus potentially lethal to the surrounding tissue and ultimately the body as these rapidly growing mutated cells take over. With the surge in cancer rates among all segments of the population, many people are attempting to reduce or eliminate their exposure to carcinogens. Titanium dioxide is regarded as an inert, non-toxic substance according to its Material Safety Data Sheet (MSDS).

Use of TiO2 photocatalytic process  for removal of airborne organic pollutants, VOCs appear to be superior to traditional technologies.
Applications of Photocatalytic Disinfection - HindawiJoanne Gamage and Zisheng Zhang

Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON, K1N6N5, Canada

The photocatalytic process is well recognized for the removal of organic pollutants in the gaseous phase such as volatile organic compounds (VOCs), having great potential applications to contaminant control in indoor environments such as residences, office buildings, factories, aircrafts, and spacecrafts [4041].

To increase the scope of the photocatalytic process in application to indoor air, the disinfection capabilities of this technique are under investigation [39]. Disinfection is of importance in indoor air applications because of the risk of exposure to harmful airborne contaminants. Bioaerosols are a major contributor to indoor air pollution, and more than 60 bacteria, viruses, and fungi are documented as infectious airborne pathogens. Diseases transmitted via bioaerosols include tuberculosis, Legionaries, influenza, colds, mumps, measles, rubella, small pox, aspergillosis, pneumonia, meningitis, diphtheria, and scarlet fever [42]. Traditional technologies to clean indoor air include the use of activated charcoal filters, HEPA filters, ozonation, air ionization, and bioguard filters. None of these technologies is completely effective [20].

In the pioneering work by Goswami et al. [4344] investigating the disinfection of indoor air by photocatalysis, a recirculating duct facility was developed to inactivate biological contaminants in air with photocatalytic techniques. Experiments using Serratia Marcescens in air achieved a 100% destruction of microorganisms in a recirculating loop in 600 minutes [43]. This time was reduced to less than 3 minutes in later experiments [45].

Photocatalytic oxidation can also inactivate infectious microorganisms which can be airborne bioterrorism weapons, such as Bacillus anthracis (Anthrax) [4648]. A photocatalytic system was investigated by Knight in 2003 to reduce the spread of severe acute respiratory syndrome (SARS) on flights [49], following the outbreak of the disease. Similarly, in 2007 the avian influenza virus A/H5N2 was shown to be inactivated from the gaseous phase using a photocatalytic prototype system [39].

 Effective Photocatalytic Disinfection of E. coli K-12 Using AgBr−Ag−Bi2WO6Nanojunction System Irradiated by Visible Light: The Role of Diffusing Hydroxyl …
LS Zhang, KH Wong, HY Yip, C Hu, JC Yu… - … science & technology, 2010 - ACS Publications
Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr−Ag−Bi2WO6 nanojunction system as a catalyst under visible light (λ ≥ 400 nm) irradiation. The visible-light-driven (VLD) AgBr−Ag−Bi2WO6 nanojunction could completely inactivate 5 × 107 cfu mL−1 E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi2WO6 superstructure, Ag−Bi2WO6 and AgBr−Ag−TiO2 composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr−Ag−Bi2WO6 nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr−Ag−Bi2WO6 nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K+) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.

Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium

The incorporation of biocidal agents into engineered polymer-based nanocomposites has led to the development of versatile antimicrobial materials that are useful for a wide variety of packaging, biomedical and general use applications1,2,3,4,5. The development of such materials is difficult because thermodynamic and kinetic barriers inhibit the dispersal of inorganic, often hydrophilic, nanoparticles in hydrophobic polymer matrixes. Antimicrobial nanocomposites based on titania (TiO2) have been actively investigated in recent years. Upon photoactivation of the oxide component, the biocidal action is a result of the modulation of charge (electron-hole) carriers at the interface of the external surface of the material, yielding potent and long-lasting capabilities when the dispersion of the inorganic phase and organic-inorganic interfacial contact are optimally achieved6,7,8,9,10,11,12. Titania has substantial advantages over both chemical (NO, H2O2, small organic molecules) and metal (typically Ag)-based systems13,14. First, titania nanoparticles have a broad spectrum of activity against microorganisms, including Gram-negative and positive-bacteria and fungi, which is of particular importance for multiple drug resistant strains13,14. Second, and more importantly, titania-polymer nanocomposites are intrinsically environmentally friendly and exert a non-contact biocidal action. Therefore, no release of potentially toxic nanoparticles (with unpredictable effects on human health) to the media is required to achieve disinfection capabilities6,7,10,11,15,16.

Additional Peer Reviewed Studies Concerning the effect of TiO2 
  1. D. M. Blake, P.-C. Maness, Z. Huang, E. J. Wolfrum, J. Huang, and W. A. Jacoby, “Application of the photocatalytic chemistry of titanium dioxide to disinfection and the killing of cancer cells,” Separation and Purification Methods, vol. 28, no. 1, pp. 1–50, 1999. View at Google Scholar
  2. K. Yogo and M. Ishikawa, “Recent progress in environmental catalytic technology,” Catalysis Surveys from Japan, vol. 4, no. 1, pp. 83–90, 2000. View at Google Scholar
  3. D. Ljubas, “Solar photocatalysis—a possible step in drinking water treatment,” Energy, vol. 30, no. 10, pp. 1699–1710, 2005. View at Publisher · View at Google Scholar
  4. H. J. Kool, C. F. Keijl, and J. Hrubec, Water Chlorination: Chemistry, Environmental Impact and Health Effects, Lewis, Chelsia, Mich, USA, 1985.
  5. P. S. M. Dunlop, J. A. Byrne, N. Manga, and B. R. Eggins, “The photocatalytic removal of bacterial pollutants from drinking water,” Journal of Photochemistry and Photobiology A, vol. 148, no. 1–3, pp. 355–363, 2002. View at Publisher · View at Google Scholar
  6. F. W. Pontis, Ed., Water Quality and Treatment, A Handbook of Community Water Supplies, Mc-Graw Hill, New York, NY, USA, 4th edition, 1990.
  7. S. Regli, “Disinfection requirements to control for microbial contamination,” in Regulating Drinking Water Quality, C. E. Gilbert and E. J. Calabrese, Eds., Lewis, Mich, USA, 1992. View at Google Scholar
  8. W. J. Masschelin, Ultraviolet Light in Water and Wastewater Sanitation, Lewis, Boca Raton, Fla, USA, 2002.
  9. J. M. C. Robertson, P. K. J. Robertson, and L. A. Lawton, “A comparison of the effectiveness of TiO2photocatalysis and UVA photolysis for the destruction of three pathogenic micro-organisms,” Journal of Photochemistry and Photobiology A, vol. 175, no. 1, pp. 51–56, 2005. View at Publisher · View at Google Scholar
  10. W.-J. Huang, G.-C. Fang, and C.-C. Wang, “The determination and fate of disinfection by-products from ozonation of polluted raw water,” Science of the Total Environment, vol. 345, no. 1-3, pp. 261–272, 2005.View at Publisher · View at Google Scholar · View at PubMed
  11. M. A. Fox, C. C. Chen, K. Park, and J. N. Younathan, in Organic Transformations in Non-Homogeneous Media, M. A. Fox, Ed., ACS Symposium Series, p. 278, 1985.
  12. A. Fujishima, T. N. Rao, and D. A. Tryk, “Titanium dioxide photocatalysis,” Journal of Photochemistry and Photobiology C, vol. 1, no. 1, pp. 1–21, 2000. View at Google Scholar
  13. A.-G. Rincón and C. Pulgarin, “Use of coaxial photocatalytic reactor (CAPHORE) in the TiO2 photo-assisted treatment of mixed E. coli and Bacillus sp. and bacterial community present in wastewater,” Catalysis Today, vol. 101, no. 3-4, pp. 331–344, 2005. View at Publisher · View at Google Scholar
  14. K. Sunada, T. Watanabe, and K. Hashimoto, “Studies on photokilling of bacteria on TiO2 thin film,” Journal of Photochemistry and Photobiology A, vol. 156, no. 1–3, pp. 227–233, 2003. View at Publisher ·View at Google Scholar
  15. T. Matsunaga, R. Tomoda, T. Nakajima, and H. Wake, “Photoelectrochemical sterilization of microbial cells by semiconductor powders,” FEMS Microbiology Letters, vol. 29, no. 1-2, pp. 211–214, 1985. View at Google Scholar
  16. C. Mccullagh, J. M. C. Robertson, D. W. Bahnemann, and P. K. J. Robertson, “The application of TiO2photocatalysis for disinfection of water contaminated with pathogenic micro-organisms: a review,” Research on Chemical Intermediates, vol. 33, no. 3-5, pp. 359–375, 2007. View at Google Scholar
  17. D. Y. Goswami and D. M. Blake, “Cleaning up with sunshine,” Mechanical Engineering, vol. 118, no. 8, pp. 56–59, 1996. View at Google Scholar
  18. D. Y. Goswami, “A review of engineering developments of aqueous phase solar photocatalytic detoxification and disinfection processes,” Journal of Solar Energy Engineering, Transactions of the ASME, vol. 119, no. 2, pp. 101–107, 1997. View at Google Scholar
  19. M. Romero, J. Blanco, B. Sánchez et al., “Solar photocatalytic degredation of water and air pollutants: challenges and perspectives,” Solar Energy, vol. 66, no. 2, pp. 169–182, 1999. View at Google Scholar
  20. D. Y. Goswami, S. Vijayaraghavan, S. Lu, and G. Tamm, “New and emerging developments in solar energy,” Solar Energy, vol. 76, no. 1-3, pp. 33–43, 2004. View at Publisher · View at Google Scholar
  21. S. Malato, J. Blanco, D. C. Alarcón, M. I. Maldonado, P. Fernández-Ibáñez, and W. Gernjak, “Photocatalytic decontamination and disinfection of water with solar collectors,” Catalysis Today, vol. 122, no. 1-2, pp. 137–149, 2007. View at Publisher · View at Google Scholar
  22. S. S. Block and D. Y. Goswami, “Chemical enhanced sunlight for killing bacteria,” in Proceedings of the ASME International Solar Energy conference, vol. 1, pp. 431–437, 1995.
  23. R. Armon, N. Laot, N. Narkis, and I. Neeman, “Photocatalytic inactivation of different bacteria and bacteriophages in drinking water at different TiO2 concentration with or without exposure to O2,” Journal of Advanced Oxidation Technologies, vol. 3, pp. 145–150, 1998. View at Google Scholar
  24. A. T. Cooper, D. Y. Goswami, and S. S. Block, “Solar photochemical detoxification and disinfection for water treatment in tropical developing countries,” Journal of Advanced Oxidation Technologies, vol. 3, no. 2, pp. 151–154, 1998. View at Google Scholar
  25. M. Biguzzi and G. Shama, “Effect of titanium dioxide concentration on the survival of Pseudomonas stutzeri during irradiation with near ultraviolet light,” Letters in Applied Microbiology, vol. 19, no. 6, pp. 458–460, 1994. View at Google Scholar
  26. H. N. Pham, T. McDowell, and E. Wilkins, “Photocatalytically-mediated disinfection of water using TiO2as a catalyst and spore-forming Bacillus pumilus as a model,” Journal of Environmental Science and Health. Part A, vol. 30, no. 3, pp. 627–636, 1995. View at Google Scholar
  27. J. C. Sjogren and R. A. Sierka, “Inactivation of phage MS2 by iron-aided titanium dioxide photocatalysis,” Applied and Environmental Microbiology, vol. 60, no. 1, pp. 344–347, 1994. View at Google Scholar
  28. R. J. Watts, S. Kong, M. P. Orr, G. C. Miller, and B. E. Henry, “Photocatalytic inactivation of coliform bacteria and viruses in secondary wastewater effluent,” Water Research, vol. 29, no. 1, pp. 95–100, 1995.View at Publisher · View at Google Scholar
  29. H. Ryu, D. Gerrity, J. C. Crittenden, and M. Abbaszadegan, “Photocatalytic inactivation of Cryptosporidium parvum with TiO2 and low-pressure ultraviolet irradiation,” Water Research, vol. 42, no. 6-7, pp. 1523–1530, 2008. View at Publisher · View at Google Scholar · View at PubMed
  30. M. Sökmen, S. Deǧerli, and A. Aslan, “Photocatalytic disinfection of Giardia intestinalis and Acanthamoeba castellani cysts in water,” Experimental Parasitology, vol. 119, no. 1, pp. 44–48, 2008. View at Publisher · View at Google Scholar · View at PubMed
  31. S. M. Karvinen, “The effects of trace element doping on the optical properties and photocatalytic activity of nanostructured titanium dioxide,” Industrial and Engineering Chemistry Research, vol. 42, no. 5, pp. 1035–1043, 2003. View at Google Scholar
  32. A. Vohra, D. Y. Goswami, D. A. Deshpande, and S. S. Block, “Enhanced photocatalytic inactivation of bacterial spores on surfaces in air,” Journal of Industrial Microbiology and Biotechnology, vol. 32, no. 8, pp. 364–370, 2005. View at Publisher · View at Google Scholar · View at PubMed
  33. E. V. Skorb, L. I. Antonouskaya, N. A. Belyasova, D. G. Shchukin, H. Möhwald, and D. V. Sviridov, “Antibacterial activity of thin-film photocatalysts based on metal-modified TiO2 and TiO2:In2O3nanocomposite,” Applied Catalysis B, vol. 84, no. 1-2, pp. 94–99, 2008. View at Publisher · View at Google Scholar
  34. J. C. Yu, W. Ho, J. Yu, H. Yip, K. W. Po, and J. Zhao, “Efficient visible-light-induced photocatalytic disinfection on sulfur-doped nanocrystalline titania,” Environmental Science and Technology, vol. 39, no. 4, pp. 1175–1179, 2005. View at Publisher · View at Google Scholar
  35. G. Li, T. An, X. Nie et al., “Mutagenicity assessment of produced water during photoelectrocatalytic degradation,” Environmental Toxicology and Chemistry, vol. 26, no. 3, pp. 416–423, 2007. View at Publisher · View at Google Scholar
  36. T. P. T. Cushnie, P. K. J. Robertson, S. Officer, P. M. Pollard, C. McCullagh, and J. M. C. Robertson, “Variables to be considered when assessing the photocatalytic destruction of bacterial pathogens,” Chemosphere, vol. 74, no. 10, pp. 1374–1378, 2009. View at Publisher · View at Google Scholar · View at PubMed
  37. Y.-S. Choi and B.-W. Kim, “Photocatalytic disinfection of E coli in a UV/TiO2-immobilised optical-fibre reactor,” Journal of Chemical Technology and Biotechnology, vol. 75, no. 12, pp. 1145–1150, 2000. View at Google Scholar
  38. M. Subrahmanyam, P. Boule, V. D. Kumari, D. N. Kumar, M. Sancelme, and A. Rachel, “Pumice stone supported titanium dioxide for removal of pathogen in drinking water and recalcitrant in wastewater,” Solar Energy, vol. 82, no. 12, pp. 1099–1106, 2008. View at Publisher · View at Google Scholar
  39. C. Guillard, T.-H. Bui, C. Felix, V. Moules, B. Lina, and P. Lejeune, “Microbiological disinfection of water and air by photocatalysis,” Comptes Rendus Chimie, vol. 11, no. 1-2, pp. 107–113, 2008. View at Publisher· View at Google Scholar
  40. D. T. Tompkins, W. A. Zeitner, B. J. Lawnicki, and M. A. Anderson, “Evaluation of photocatalysis for gas-phase air cleanin—part 1: process, technical, and sizing considerations,” ASHRAE Transactions, vol. 111, no. 2, pp. 60–84, 2005. View at Google Scholar
  41. D. F. Ollis, “Photocatalytic purification and remediation of contaminated air and water,” Comptes Rendus de l'Academie des Sciences IIC 3, vol. 3, no. 6, pp. 405–411, 2000. View at Google Scholar
  42. W. A. Jacoby, P. C. Maness, E. J. Wolfrum, D. M. Blake, and J. A. Fennell, “Mineralization of bacterial cell mass on a photocatalytic surface in air,” Environmental Science and Technology, vol. 32, no. 17, pp. 2650–2653, 1998. View at Publisher · View at Google Scholar
  43. D. Y. Goswami, D. M. Trivedi, and S. S. Block, “Photocatalytic disinfection of indoor air,” Journal of Solar Energy Engineering, Transactions of the ASME, vol. 119, no. 1, pp. 92–96, 1997. View at Google Scholar
  44. D. Y. Goswami, D. M. Trivedi, and S. S. Block, “Photocatalytic disinfection of indoor air,” Journal of Solar Energy Engineering, Transactions of the ASME, vol. 119, no. 1, pp. 92–96, 1997. View at Google Scholar
  45. T. K. Goswami, S. Hingorani, H. Griest, D. Y. Goswami, and S. S. Block, “Photocatalytic system to destroy bioaerosols in air,” Journal of Advanced Oxidation Technologies, vol. 4, no. 2, pp. 185–188, 1999.View at Google Scholar
  46. H. T. Griest, S. K. Hingorani, K. Kelly, and D. Y. Goswami, “Using scanning electron microscopy to visualize the photocatalytic mineralization of airborne microorganisms,” in Proceedings of the 9th International Conference on Indoor Air Quality and Climate, Processing of the Indoor Air, pp. 712–717, Monterey, Calif, USA, 2002.
  47. C. Lee, H. Choi, C. Lee, and H. Kim, “Photocatalytic properties of nano-structured TiO2 plasma sprayed coating,” Surface and Coatings Technology, vol. 173, no. 2-3, pp. 192–200, 2003. View at Publisher · View at Google Scholar
  48. J.-H. Kau, D.-S. Sun, H.-H. Huang, M.-S. Wong, H.-C. Lin, and H.-H. Chang, “Role of visible light-activated photocatalyst on the reduction of anthrax spore-induced mortality in mice,” PLoS ONE, vol. 4, no. 1, pp. 1–8, 2009. View at Publisher · View at Google Scholar · View at PubMed
  49. H. Knight, “Sars wars,” Engineer, vol. 292, pp. 27–35, 2003. View at Google Scholar
  50. D. Mitoraj, A. Jańczyk, M. Strus et al., “Visible light inactivation of bacteria and fungi by modified titanium dioxide,” Photochemical and Photobiological Sciences, vol. 6, no. 6, pp. 642–648, 2007. View at Publisher · View at Google Scholar · View at PubMed
  51. A. Pal, S. O. Pehkonen, L. E. Yu, and M. B. Ray, “Photocatalytic inactivation of Gram-positive and Gram-negative bacteria using fluorescent light,” Journal of Photochemistry and Photobiology A, vol. 186, no. 2-3, pp. 335–341, 2007. View at Publisher · View at Google Scholar
  52. E. J. Wolfrum, J. Huang, D. M. Blake et al., “Photocatalytic oxidation of bacteria, bacterial and fungal spores, and model biofilm components to carbon dioxide on titanium dioxide-coated surfaces,” Environmental Science and Technology, vol. 36, no. 15, pp. 3412–3419, 2002. View at Publisher · View at Google Scholar
  53. J. Kiwi and V. Nadtochenko, “New evidence for TiO2 photocatalysis during bilayer lipid peroxidation,” Journal of Physical Chemistry B, vol. 108, no. 45, pp. 17675–17684, 2004. View at Publisher · View at Google Scholar
  54. R. Basca, J. Kiwi, T. Ohno, P. Albers, and V. Nadtochenko, “Preparation, testing and characterization of doped TiO2 able to transform biomolecules under visible light irradiation by peroxidation/oxidation,” Journal Physical Chemistry B, vol. 109, pp. 5994–6003, 2005. View at Google Scholar
  55. J. Kiwi and V. Nadtochenko, “Evidence for the mechanism of photocatalytic degradation of the bacterial wall membrane at the TiO2 interface by ATR-FTIR and laser kinetic spectroscopy,” Langmuir, vol. 21, no. 10, pp. 4631–4641, 2005. View at Publisher · View at Google Scholar
  56. V. A. Nadtochenko, A. G. Rincon, S. E. Stanca, and J. Kiwi, “Dynamics of E. coli membrane cell peroxidation during TiO2 photocatalysis studied by ATR-FTIR spectroscopy and AFM microscopy,” Journal of Photochemistry and Photobiology A, vol. 169, no. 2, pp. 131–137, 2005. View at Publisher ·View at Google Scholar
  57. V. Nadtochenko, C. Pulgarin, P. Bowen, and J. Kiwi, “Laser spectroscopy of the interaction of bacterial wall membranes and E. coli with TiO2,” Journal of Photochemistry and Photobiology A, vol. 181, pp. 401–404, 2006. View at Google Scholar
  58. M. P. Paschoalino and W. F. Jardim, “Indoor air disinfection using a polyester supported TiO2 photo-reactor,” Indoor Air, vol. 18, no. 6, pp. 473–479, 2008. View at Publisher · View at Google Scholar · View at PubMed
  59. V. Krishna, S. Pumprueg, S.-H. Lee et al., “Photocatalytic disinfection with titanium dioxide coated multi-wall carbon nanotubes,” Process Safety and Environmental Protection, vol. 83, no. 4 B, pp. 393–397, 2005. View at Publisher · View at Google Scholar
  60. S. A. Grinshpun, A. Adhikari, T. Honda et al., “Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation,” Environmental Science and Technology, vol. 41, no. 2, pp. 606–612, 2007. View at Publisher · View at Google Scholar
  61. A. Pal, X. Mint, L. E. Yu, S. O. Pehkonen, and M. B. Ray, “Photocatalytic inactivation of bioaerosols by TiO2 coated membrane,” International Journal of Chemical Reactor Engineering, vol. 3, p. A45, 2005. View at Google Scholar
  62. T. Yuranova, A. G. Rincon, A. Bozzi et al., “Antibacterial textiles prepared by RF-plasma and vacuum-UV mediated deposition of silver,” Journal of Photochemistry and Photobiology A, vol. 161, no. 1, pp. 27–34, 2003. View at Publisher · View at Google Scholar
  63. T. Yuranova, A. G. Rincon, C. Pulgarin, D. Laub, N. Xantopoulos, and H.-J. Mathieu, “Bactericide cotton textiles active in E. coli abatement prepared under mild preparation conditions,” Journal of Photochemistry and Photobiology A, vol. 181, pp. 363–369, 2006. View at Google Scholar
  64. M. I. Mejia, G. Restrepo, J. M. Marin, R. Sanjines, C. Pulgarin, and E. Mielczarski, “Magnetron-sputtered Ag surfaces. New evidence for the nature of the Ag ions intervening in bacterial inactivation,” JACS Applied Materials and Interfaces, vol. 2, pp. 230–235, 2010. View at Google Scholar
  65. M. Paschoalino, N. C. Guedes, W. Jardim, E. Mielczarski, K. Mielczarski, and P. Bowen, “Photo-assisted inactivation of E. coli by high surface area CuO under light irradiation (>360 nm),” Journal of Photochemistry and Photobiology A, vol. 199, pp. 105–111, 2008. View at Google Scholar
  66. A. Moncayo-Lasso, R. A. Torres-Palma, J. Kiwi, N. Benítez, and C. Pulgarin, “Bacterial inactivation and organic oxidation via immobilized photo-Fenton reagent on structured silica surfaces,” Applied Catalysis B, vol. 84, no. 3-4, pp. 577–583, 2008. View at Publisher · View at Google Scholar
  67. F. Chen, X. Yang, and Q. Wu, “Antifungal capability of TiO2 coated film on moist wood,” Building and Environment, vol. 44, no. 5, pp. 1088–1093, 2009. View at Publisher · View at Google Scholar
  68. P. Kern, P. Schwaller, and J. Michler, “Electrolytic deposition of titania films as interference coatings on biomedical implants: microstructure, chemistry and nano-mechanical properties,” Thin Solid Films, vol. 494, no. 1-2, pp. 279–286, 2006. View at Publisher · View at Google Scholar
  69. P. Evans and D. W. Sheel, “Photoactive and antibacterial TiO2 thin films on stainless steel,” Surface and Coatings Technology, vol. 201, no. 22-23, pp. 9319–9324, 2007. View at Publisher · View at Google Scholar
  70. K. Shiraishi, H. Koseki, T. Tsurumoto et al., “Antibacterial metal implant with a TiO2-conferred photocatalytic bactericidal effect against Staphylococcus aureus,” Surface and Interface Analysis, vol. 41, no. 1, pp. 17–22, 2009. View at Publisher · View at Google Scholar
  71. Y. Kubota, T. Shuin, C. Kawasaki et al., “Photokilling of T-24 human bladder cancer cells with titanium dioxide,” British Journal of Cancer, vol. 70, no. 6, pp. 1107–1111, 1994. View at Google Scholar
  72. H. Irie, K. Sunada, and K. Hashimoto, “Recent developments in TiO2 photocatalysis: novel applications to interior ecology materials and energy saving systems,” Electrochemistry, vol. 72, no. 12, pp. 807–812, 2004. View at Google Scholar
  73. S.-H. Lee, S. Pumprueg, B. Moudgil, and W. Sigmund, “Inactivation of bacterial endospores by photocatalytic nanocomposites,” Colloids and Surfaces B, vol. 40, no. 2, pp. 93–98, 2005. View at Publisher · View at Google Scholar · View at PubMed
  74. K. P. Kühn, I. F. Chaberny, K. Massholder et al., “Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UVA light,” Chemosphere, vol. 53, no. 1, pp. 71–77, 2003. View at Publisher ·View at Google Scholar · View at PubMed
  75. Y. Kikuchi, K. Sunada, T. Iyoda, K. Hashimoto, and A. Fujishima, “Photocatalytic bactericidal effect of TiO2 thin films: dynamic view of the active oxygen species responsible for the effect,” Journal of Photochemistry and Photobiology A, vol. 106, no. 1–3, pp. 51–56, 1997. View at Google Scholar
  76. P. Evans, T. English, D. Hammond, M. E. Pemble, and D. W. Sheel, “The role of SiO2 barrier layers in determining the structure and photocatalytic activity of TiO2 films deposited on stainless steel,” Applied Catalysis A, vol. 321, no. 2, pp. 140–146, 2007. View at Publisher · View at Google Scholar
  77. L. Caballero, K. A. Whitehead, N. S. Allen, and J. Verran, “Inactivation of Escherichia coli on immobilized TiO2 using fluorescent light,” Journal of Photochemistry and Photobiology A, vol. 202, no. 2-3, pp. 92–98, 2009. View at Publisher · View at Google Scholar
  78. J. C. Yu, W. Ho, J. Lin, H. Yip, and P. K. Wong, “Photocatalytic activity, antibacterial effect, and photoinduced hydrophilicity of TiO2 films coated on a stainless steel substrate,” Environmental Science and Technology, vol. 37, no. 10, pp. 2296–2301, 2003. View at Publisher · View at Google Scholar
  79. K. Sunada, T. Watanabe, and K. Hashimoto, “Bactericidal activity of copper-deposited TiO2 thin film under weak UV light illumination,” Environmental Science and Technology, vol. 37, no. 20, pp. 4785–4789, 2003. View at Publisher · View at Google Scholar
  80. M.-S. Wong, W.-C. Chu, D.-S. Sun et al., “Visible-light-induced bactericidal activity of a nitrogen-doped titanium photocatalyst against human pathogens,” Applied and Environmental Microbiology, vol. 72, no. 9, pp. 6111–6116, 2006. View at Publisher · View at Google Scholar · View at PubMed
  81. J. A. Rengifo-Herrera, E. Mielczarski, J. Mielczarski, N. C. Castillo, J. Kiwi, and C. Pulgarin, “Escherichia coli inactivation by N, S co-doped commercial TiO2 powders under UV and visible light,” Applied Catalysis B, vol. 84, no. 3-4, pp. 448–456, 2008. View at Publisher · View at Google Scholar
  82. J. A. Rengifo-Herrera, K. Pierzchała, A. Sienkiewicz, L. Forró, J. Kiwi, and C. Pulgarin, “Abatement of organics and Escherichia coli by N, S co-doped TiO2 under UV and visible light. Implications of the formation of singlet oxygen (1O2) under visible light,” Applied Catalysis B, vol. 88, no. 3-4, pp. 398–406, 2009. View at Publisher · View at Google Scholar
  83. J. A. Rengifo-Herrera, J. Kiwi, and C. Pulgarin, “N, S co-doped and N-doped Degussa P-25 powders with visible light response prepared by mechanical mixing of thiourea and urea. Reactivity towards E. coliinactivation and phenol oxidation,” Journal of Photochemistry and Photobiology A, vol. 205, no. 2-3, pp. 109–115, 2009. View at Publisher · View at Google Scholar
  84. J. A. Renigo-Herrera, A. Sienkiewicz, L. Forro, J. Kiwi, J. E. Moser, and C. Pulgarin, “New evidence for the nature of the N, S, co-doped TiO2 sited under visible light leading to E. coli inactivation. Catalyst characterization,” Journal of Physical Chemistry, vol. 114, pp. 2717–2723, 2010. View at Google Scholar
  85. B. A. Walther and P. W. Ewald, “Pathogen survival in the external environment and the evolution of virulence,” Biological Reviews of the Cambridge Philosophical Society, vol. 79, no. 4, pp. 849–869, 2004.View at Publisher · View at Google Scholar
  86. K.-T. Chen, P.-Y. Chen, R.-B. Tang et al., “Sentinel hospital surveillance for rotavirus diarrhea in Taiwan, 2001–2003,” Journal of Infectious Diseases, vol. 192, no. 1, pp. S44–S48, 2005. View at Publisher · View at Google Scholar · View at PubMed
  87. N. Laot, N. Narkis, I. Neeman, and R. Armon, “TiO2 photocatalytic inactivation of selected microorganisms under various conditions: sunlight, intermittent and variable irradiation intensity, CdS supplementation and entrapment of TiO2 into sol-gel,” Journal of Advanced Oxidation Technologies, vol. 4, pp. 97–102, 1999. View at Google Scholar
  88. Y. W. Cheng, R. C. Y. Chan, and P. K. Wong, “Disinfection of Legionella pneumophila by photocatalytic oxidation,” Water Research, vol. 41, no. 4, pp. 842–852, 2007. View at Publisher · View at Google Scholar ·View at PubMed
  89. Centers for Disease Control and Prevention, Hospital Control Practices Advisory Committee, “Guidelines for prevention of nosocomial pneumonia,” CDC’s Morbidity and Mortality Weekly Reporter, vol. 46, pp. 1–79, 1997. View at Google Scholar
  90. C. Chawengkijwanich and Y. Hayata, “Development of TiO2 powder-coated food packaging film and its ability to inactivate Escherichia coli in vitro and in actual tests,” International Journal of Food Microbiology, vol. 123, no. 3, pp. 288–292, 2008. View at Publisher · View at Google Scholar · View at PubMed
  91. A. K. Benabbou, Z. Derriche, C. Felix, P. Lejeune, and C. Guillard, “Photocatalytic inactivation of Escherischia coli. Effect of concentration of TiO2 and microorganism, nature, and intensity of UV irradiation,” Applied Catalysis B, vol. 76, no. 3-4, pp. 257–263, 2007. View at Publisher · View at Google Scholar
  92. Y. Liu, J. Li, X. Qiu, and C. Burda, “Bactericidal activity of nitrogen-doped metal oxide nanocatalysts and the influence of bacterial extracellular polymeric substances (EPS),” Journal of Photochemistry and Photobiology A, vol. 190, no. 1, pp. 94–100, 2007. View at Publisher · View at Google Scholar
  93. H. Matsubara, M. Takada, and S. Koyama, “Research on application of photoactive TiO2 to paper,” Kinoshi Kenkyu Kaishi, vol. 34, pp. 36–39, 1996. View at Google Scholar
  94. J. Blanco, S. Malato, P. Fernández-Ibañez, D. Alarcón, W. Gernjak, and M. I. Maldonado, “Review of feasible solar energy applications to water processes,” Renewable and Sustainable Energy Reviews, vol. 13, no. 6-7, pp. 1437–1445, 2009. View at Publisher · View at Google Scholar
  95. K. S. Yao, D. Y. Wang, W. Y. Ho, J. J. Yan, and K. C. Tzeng, “Photocatalytic bactericidal effect of TiO2 thin film on plant pathogens,” Surface and Coatings Technology, vol. 201, no. 15, pp. 6886–6888, 2007. View at Publisher · View at Google Scholar
  96. K. S. Yao, D. Y. Wang, C. Y. Chang et al., “Photocatalytic disinfection of phytopathogenic bacteria by dye-sensitized TiO2 thin film activated by visible light,” Surface and Coatings Technology, vol. 202, no. 4-7, pp. 1329–1332, 2007. View at Publisher · View at Google Scholar
  97. C. Sichel, M. de Cara, J. Tello, J. Blanco, and P. Fernández-Ibáñez, “Solar photocatalytic disinfection of agricultural pathogenic fungi: Fusarium species,” Applied Catalysis B, vol. 74, no. 1-2, pp. 152–160, 2007.View at Publisher · View at Google Scholar
  98. D. Sawada, M. Ohmasa, M. Fukuda et al., “Disinfection of some pathogens of mushroom cultivation by photocatalytic treatment,” Mycoscience, vol. 46, no. 1, pp. 54–60, 2005. View at Publisher · View at Google Scholar
  99. R. Dillert, S. Vollmer, M. Schober et al., “Pilot plant studies on the photocatalytic oxidation of a pretrated industrial wastewater,” GWF Wasser Abwasser, vol. 140, no. 4, pp. 293–297, 1999. View at Google Scholar
  100. R. Dillert, S. Vollmer, E. Gross et al., “Solar-catalytic treatment of an industrial wastewater,” Zeitschrift fur Physikalische Chemie, vol. 213, no. 2, pp. 141–147, 1999. View at Google Scholar
  101. R. Dillert, S. Vollmer, M. Schober et al., “Photokatalytische behandlung eines industriabwassers im stegdoppelplattenreaktor,” Chemie Ingenieur Tecnik, vol. 71, pp. 396–399, 1999. View at Google Scholar
  102. D. Bahnemann, “Photocatalytic water treatment: solar energy applications,” Solar Energy, vol. 77, no. 5, pp. 445–459, 2004. View at Publisher · View at Google Scholar
  103. J. Blanco and S. Malato, “Solar photocatalytic mineralization of real hazardous waste water at pre-industrial level,” in Proceedings of the ASME/JSME/JSES International Solar Energy Conference, D. E. Klett, R. E. Hogan, and T. Tanaka, Eds., pp. 103–109, San Francisco, Calif, USA, 1994.
  104. M. Anhegen, D. Y. Goswami, and G. Svedberg, “Photocatalytic treatment of wastewater from 5-fluoracil manufacturing,” in Proceedings of the ASME/JSME/JSES International Solar Energy Conference, Maui, Hawaii, 1995.
  105. A. H. Zaidi, D. Y. Goswami, and A. C. Wilkie, “Solar photocatalytic post-treatment of anaerobically digested distillery effluent,” in Proceedings of the American Solar Energy Society Annual Conference, pp. 51–56, Minneapolis, Minn, USA, 1995.
  106. C. S. Turchi, L. Edmunson, and D. F. Ollis, “Application of heterogeneous photocatalysis for the destruction of organic contaminants from a paper mill alkali extraction process,” in Proceedings of the TAPPI 5th International Symposium on Wood and Pulping Chemistry, Raleigh, NC, USA, 1989.
  107. O. Seven, B. Dindar, S. Aydemir, D. Metin, M. A. Ozinel, and S. Icli, “Solar photocalytic disinfection of a group of bacteria and fungi aqueous suspensions with TiO2, ZnO and sahara desert dust,” Journal of Photochemistry and Photobiology A, vol. 165, no. 1–3, pp. 103–107, 2004. View at Publisher · View at Google Scholar
  108. M. Otaki, T. Hirata, and S. Ohgaki, “Aqueous microorganisms inactivation by photocatalytic reaction,” Water Science and Technology, vol. 42, no. 3-4, pp. 103–108, 2000. View at Google Scholar
  109. T. Kato, T. Shibata, H. Tohma, M. Tamura, and O. Miki, “Degredation of norovirus in sewage treatment water by photocatalytic ultraviolent disinfection,” Nippon Steel Technical Report, pp. 41–44, 92. View at Google Scholar
  110. R. Dillert, U. Siemon, and D. Bahnemann, “Photocatalytic disinfection of municipal wastewater,” Chemical Engineering and Technology, vol. 21, no. 4, pp. 356–358, 1998. View at Google Scholar
  111. J. A. Herrera Melián, J. M. Doña Rodríguez, A. Viera Suárez et al., “The photocatalytic disinfection of urban waste waters,” Chemosphere, vol. 41, no. 3, pp. 323–327, 2000. View at Publisher · View at Google Scholar
  112. A.-G. Rincón and C. Pulgarin, “Bactericidal action of illuminated TiO2 on pure Escherichia coli and natural bacterial consortia: post-irradiation events in the dark and assessment of the effective disinfection time,” Applied Catalysis B, vol. 49, no. 2, pp. 99–112, 2004. View at Publisher · View at Google Scholar
  113. A. G. Rincón and C. Pulgarin, “Photocatalytical inactivation of E. coli: effect of (continuous-intermittent) light intensity and of (suspended-fixed) TiO2 concentration,” Applied Catalysis B, vol. 44, no. 3, pp. 263–284, 2003. View at Publisher · View at Google Scholar
  114. Y. LI, M. Ma, X. Wang, and X. Wang, “Inactivated properties of activated carbon-supported TiO2nanoparticles for bacteria and kinetic study,” Journal of Environmental Sciences, vol. 20, no. 12, pp. 1527–1533, 2008. View at Publisher · View at Google Scholar
  115. H. Choi, A. C. Sofranko, and D. D. Dionysiou, “Nanocrystalline TiO2 photocatalytic membranes with a hierarchical mesoporous multilayer structure: synthesis, characterization, and multifunction,” Advanced Functional Materials, vol. 16, no. 8, pp. 1067–1074, 2006. View at Publisher · View at Google Scholar
  116. H. Choi, E. Stathatos, and D. D. Dionysiou, “Photocatalytic TiO2 films and membranes for the development of efficient wastewater treatment and reuse systems,” Desalination, vol. 202, no. 1-3, pp. 199–206, 2007. View at Publisher · View at Google Scholar
  117. Y. Liu, J. Li, X. Qiu, and C. Burda, “Novel TiO2 nanocatalysts for wastewater purification: tapping energy from the sun,” Water Science and Technology, vol. 54, no. 8, pp. 47–54, 2006. View at Publisher · View at Google Scholar
  118. P. H. Gleick, World’s Water 2004-2005, Island Press, Washington, DC, USA, 2004.
  119. L. Villen, F. Manjon, D. Garcia-Fresnadillo, and G. Orellana, “Solar water disinfection by photocatalytic singlet oxygen production in heterogenous medium,” Applied Catalysis B, vol. 69, pp. 1–9, 2006. View at Google Scholar
  120. I. Najm and R. R. Trussel, “New and emerging drinking water treatment technologies,” in Identifying Future Drinking Water Contaminants, p. 220, National Academy, Washington, DC, USA, 1999. View at Google Scholar
  121. M. Boyle, C. Sichel, P. Fernández-Ibáñez et al., “Bactericidal effect of solar water disinfection under real sunlight conditions,” Applied and Environmental Microbiology, vol. 74, no. 10, pp. 2997–3001, 2008. View at Publisher · View at Google Scholar · View at PubMed
  122. E. Ubomba-Jaswa, C. Navntoft, I. Polo-López, P. Fernández-Ibáñez, and K. G. McGuigan, “Solar disinfection of drinking water (SODIS): an investigation of the effect of UVA dose on inactivation efficiency,” Photochemistry and Photobiological Sciences, vol. 8, no. 5, pp. 587–595, 2009. View at Google Scholar
  123. H. Gómez-Couso, M. Fontán-Saínz, C. Sichel, P. Fernández-Ibáñez, and E. Ares-Mazás, “Solar disinfection of turbid waters experimentally contaminated with Cryptosporidium parvum oocysts under real field conditions,” Tropical Medicineand International Health, vol. 14, no. 6, pp. 1–9, 2009. View at Google Scholar
  124. E. Ubomba-Jaswa, P. Fernández-Ibáñez, C. Navntoft, M. Inmaculada Polo-Lópezb, and K. G. McGuigana, “Investigating the microbial inactivation efficiency of a 25 L batch solar disinfection (SODIS) reactor enhanced with a compound parabolic collector (CPC) for household use,” Journal of Chemical Technology and Biotechnology, vol. 85, no. 8, pp. 1028–1037, 2010. View at Publisher · View at Google Scholar
  125. O. A. McLoughlin, P. Fernández-Ibáñez, W. Gernjak, S. Malato Rodriguez, and L. W. Gill, “Photocatalytic disinfection of water using low cost compound parabolic collectors,” Solar Energy, vol. 77, no. 5, pp. 625–633, 2004. View at Publisher · View at Google Scholar
  126. A.-G. Rincón and C. Pulgarin, “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?” Solar Energy, vol. 77, no. 5, pp. 635–648, 2004. View at Publisher · View at Google Scholar
  127. C. Navntoft, P. Araujo, M. I. Litter et al., “Field tests of the solar water detoxification SOLWATER reactor in Los Pereyra, Tucumán, Argentina,” Journal of Solar Energy Engineering, Transactions of the ASME, vol. 129, no. 1, pp. 127–134, 2007. View at Publisher · View at Google Scholar
  128. E. F. Duffy, F. Al Touati, S. C. Kehoe et al., “A novel TiO2-assisted solar photocatalytic batch-process disinfection reactor for the treatment of biological and chemical contaminants in domestic drinking water in developing countries,” Solar Energy, vol. 77, no. 5, pp. 649–655, 2004. View at Publisher · View at Google Scholar
  129. F. Méndez-Hermida, E. Ares-Mazás, K. G. McGuigan, M. Boyle, C. Sichel, and P. Fernández-Ibáñez, “Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2,” Journal of Photochemistry and Photobiology B, vol. 88, no. 2-3, pp. 105–111, 2007. View at Publisher · View at Google Scholar · View at PubMed
  130. H. Gómez-Couso, M. Fontán-Sainz, J. Fernández-Alonso, and E. Ares-Mazás, “Excystation of Cryptosporidium parvum at temperatures that are reached during solar water disinfection,” Parasitology, vol. 136, no. 4, pp. 393–399, 2009. View at Publisher · View at Google Scholar · View at PubMed
  131. K. G. McGuigan, F. Méndez-Hermida, J. A. Castro-Hermida et al., “Batch solar disinfection inactivates oocysts of Cryptosporidium parvum and cysts of Giardia muris in drinking water,” Journal of Applied Microbiology, vol. 101, no. 2, pp. 453–463, 2006. View at Publisher · View at Google Scholar · View at PubMed
  132. A.-G. Rincón and C. Pulgarin, “Effect of pH, inorganic ions, organic matter and H2O2 on E. coli K12 photocatalytic inactivation by TiO2: implications in solar water disinfection,” Applied Catalysis B, vol. 51, no. 4, pp. 283–302, 2004. View at Publisher · View at Google Scholar
  133. J. Marugán, R. van Grieken, C. Sordo, and C. Cruz, “Kinetics of the photocatalytic disinfection of Escherichia coli suspensions,” Applied Catalysis B, vol. 82, no. 1-2, pp. 27–36, 2008. View at Publisher ·View at Google Scholar
  134. J. C. Ireland, P. Klostermann, E. W. Rice, and R. M. Clark, “Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation,” Applied and Environmental Microbiology, vol. 59, no. 5, pp. 1668–1670, 1993. View at Google Scholar
  135. J. Wist, J. Sanabria, C. Dierolf, W. Torres, and C. Pulgarin, “Evaluation of photocatalytic disinfection of crude water for drinking-water production,” Journal of Photochemistry and Photobiology A, vol. 147, no. 3, pp. 241–246, 2002. View at Publisher · View at Google Scholar
  136. C. A. Murray, E. H. Goslan, and S. A. Parsons, “TiO2/UV: single stage drinking water treatment for NOM removal?” Journal of Environmental Engineering and Science, vol. 6, no. 3, pp. 311–317, 2007. View at Publisher · View at Google Scholar
  137. S.-C. Kim and D.-K. Lee, “Inactivation of algal blooms in eutrophic water of drinking water supplies with the photocatalysis of TiO2 thin film on hollow glass beads,” Water Science and Technology, vol. 52, no. 9, pp. 145–152, 2005. View at Google Scholar
  138. A. J. Feitz, T. D. Waite, G. J. Jones, B. H. Boyden, and P. T. Orr, “Photocatalytic degredation of the blue-green algal toxin Microcystin-LR in a natural organic-aqueous matrix,” Environmental Science and Technology, vol. 33, no. 2, pp. 243–249, 1999. View at Google Scholar
  139. D. Y. Goswami, J. Klausner, G. D. Mathur et al., “Solar photocatalytic treatment of groundwater at Tyndall AFB, field test results,” in Proceedings of the American Solar Energy Society Annual Conference, Washington, DC, USA, 1993.
  140. P. Fernández-Ibáñez, C. Sichel, M. I. Polo-López, M. de Cara-García, and J. C. Tello, “Photocatalytic disinfection of natural well water contaminated by Fusarium solani using TiO2 slurry in solar CPC photo-reactors,” Catalysis Today, vol. 144, no. 1-2, pp. 62–68, 2009. View at Publisher · View at Google Scholar
  141. M. I. Polo-López, P. Fernández-Ibáñez, I. García-Fernández, I. Oller, I. Salgado-Tránsito, and C. Sichel, “Resistance of Fusarium sp spores to solar TiO2 photocatalysis: influence of spore type and water (scaling-up results),” Journal of Chemical Technology and Biotechnology, vol. 85, pp. 1038–1048, 2010.View at Google Scholar




This is the 3rd largest hospital company in the world with over 200 hospitals and clinics around the world! (Saudi Arabia, London, Toronto, etc.) 
Ranked #2 for care in the US!  We spent a day with many of their executive staff, Department Heads, etc.   This letter from a member of their governing board, and one of the top kidney transplant surgeons in the world, is the result. The interest is extremely high.