Photocatalytic water disinfection of Cryptosporidium parvum and Giardia lamblia using a fibrous ceramic TiO2 photocatalyst

2009 ◽  
Vol 59 (4) ◽  
pp. 639-645 ◽  
Author(s):  
Sergio Navalon ◽  
Mercedes Alvaro ◽  
Hermenegildo Garcia ◽  
Daniel Escrig ◽  
Víctor Costa
Keyword(s):  
Adverse Effects ◽  
Cryptosporidium Parvum ◽  
Giardia Lamblia ◽  
Continuous Flow ◽  
Uv Light ◽  
Small Concentration ◽  
Water Disinfection ◽  
Photocatalytic Process ◽  
Tio2 Photocatalyst ◽  
Low Concentrations

Cryptosporidium parvum and Giardia lamblia are two of the most chlorine resistant microorganisms with notable adverse effects on humans. Our study shows that waters containing these two protozoa at low concentrations can be efficiently disinfected in continuous flow by using a commercial fibrous ceramic TiO2 photocatalyst. The efficiency of the photocatalytic disinfection is largely enhanced by adding a small concentration of chlorine. In this way, the residence time on the photoreactor can be considerably shortened. In contrast, under the same conditions and radiance power, UV light without any photocatalyst is significantly less efficient, particularly for G. lamblia. These results exemplify the advantages of the photocatalytic process for safe and complete water disinfection.

Excystation ofCryptosporidium parvumat temperatures that are reached during solar water disinfection

Parasitology ◽  
2009 ◽  
Vol 136 (4) ◽  
pp. 393-399 ◽  
Author(s):  
H. GÓMEZ-COUSO ◽  
M. FONTÁN-SAINZ ◽  
J. FERNÁNDEZ-ALONSO ◽  
E. ARES-MAZÁS
Keyword(s):  
Solar Radiation ◽  
Cryptosporidium Parvum ◽  
Gradual Increase ◽  
Water Disinfection ◽  
Waterborne Diseases ◽  
Pathogenic Microorganisms ◽  
Simple Method ◽  
Solar Water ◽  
Solar Water Disinfection ◽  
Notable Increase

SUMMARYSpecies belonging to the generaCryptosporidiumare recognized as waterborne pathogens. Solar water disinfection (SODIS) is a simple method that involves the use of solar radiation to destroy pathogenic microorganisms that cause waterborne diseases. A notable increase in water temperature and the existence of a large number of empty or partially excysted (i.e. unviable) oocysts have been observed in previous SODIS studies with water experimentally contaminated withCryptosporidium parvumoocysts under field conditions. The aim of the present study was to evaluate the effect of the temperatures that can be reached during exposure of water samples to natural sunlight (37–50°C), on the excystation ofC. parvumin the absence of other stimuli. In samples exposed to 40–48°C, a gradual increase in the percentage of excystation was observed as the time of exposure increased and a maximum of 53·81% of excystation was obtained on exposure of the water to a temperature of 46°C for 12 h (versus8·80% initial isolate). Under such conditions, the oocyst infectivity evaluated in a neonatal murine model decreased statistically with respect to the initial isolate (19·38%versus100%). The results demonstrate the important effect of the temperature on the excystation ofC. parvumand therefore on its viability and infectivity.

Kinetic study on degradation of gaseous acetone over thin-film TiO2 photocatalyst in a continuous flow system

2007 ◽  
Vol 90 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Sung Hyun Kim ◽  
Sang Bum Kim ◽  
Gyung Soo Kim ◽  
Hyun Tae Jang ◽  
Sung Chang Hong
Keyword(s):  
Thin Film ◽  
Kinetic Study ◽  
Continuous Flow ◽  
Flow System ◽  
Tio2 Photocatalyst ◽  
Continuous Flow System

scholarly journals Visible Light-Induced Superior Photocatalytic Activity of Ag@Nd2WO6/ZnO Nanocomposite and its Biological Activity

2019 ◽  
Vol 9 (2S2) ◽  
pp. 232-236
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Uv Light ◽  
Uv Spectroscopy ◽  
Photocatalytic Process ◽  
Spectroscopy Technique ◽  
Phase Purity ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Catalytic Material

In this work, degradation of Ciprofloxacin has been studied over the catalyst Ag@Nd2WO6/ZnO (ANWZ) synthesized via hydrothermal method. The catalysts are characterized with techniques such as X-ray diffractometer, Scanning electron microscope with EDX spectroscopy and DRS- UV spectroscopy respectively. For the results shows, the PXRD spectroscopy was confirmed a phase purity and crystalline structure of the as-synthesized catalyst. The SEM results are explained about the morphology structure of the material, the structure spherical with nanorod like clustered morphology structure was shown in SEM and the reacting elements in the catalytic material are confirmed by EDX spectroscopy. And the DRS-UV spectroscopy technique is telling about the band energy value for prepared materials and also select the suitable way (i.e: Visible or UV light irradiation) for the degradation. The photocatalytic process, Ciprofloxacin (CIP) drug are degraded under visible light within 140 minutes and the degradation efficiency are 95.54%. The reusability test explains the efficiency and stability of the ANWZ catalyst and its stable up to the fifth run. Further, the photodegradation process, the catalyst is tested antibacterial activity study against Bacillus cereus and Escherichia Coli bacterial organisms. From the result, Bacillus bacteria contain more efficient antibacterial activity than that of E.coli bacteria

scholarly journals A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1039
Author(s):  
Dafu Jiang ◽  
Tunmise Ayode Otitoju ◽  
Yuanyuan Ouyang ◽  
Noor Fazliani Shoparwe ◽  
Song Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Active Sites ◽  
Crystal Surface ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Tio2 Photocatalyst ◽  
Electron Hole ◽  
Visible Light Range ◽  
Low Toxicity ◽  
High Chemical Stability

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

scholarly journals PENGGUNAAN TABIR SURYA BAGI KESEHATAN KULIT

2019 ◽  
Vol 11 (1) ◽  
pp. 87
Author(s):  
Prima Minerva
Keyword(s):  
Skin Cancer ◽  
Adverse Effects ◽  
Uv Light ◽  
Light Exposure ◽  
Premature Aging ◽  
Negative Effects ◽  
Physical Protection ◽  
Skin Immunity ◽  
Long Time ◽  
The Right

Most activities are done outside the home often make the skin exposed to UV light. Exposure UV light excessively or in a long time can cause the occurrence of skin disorders such as Sunburn, premature aging, lowering skin immunity to skin cancer. In preventing the negative effects of UV light on the skin, various ways can be done such as by using a protector such as clothes, hats, glasses or umbrellas. But this physical protection is not sufficient because of the UV light penetrating power. Sunscreen is a skin care cosmetic that provides physical protection against UV light. Proper use of sunscreen and routine can protect the skin from the negative effects of UV light. This paper describes the effects of UV light on the skin, the function of sunscreen and the right use and compatible types sunscreen in maintaining skin health from the adverse effects of UV light.

scholarly journals Detection of UV-Induced Thymine Dimers in Individual Cryptosporidium parvum and Cryptosporidium hominis Oocysts by Immunofluorescence Microscopy

2006 ◽  
Vol 73 (3) ◽  
pp. 947-955 ◽  
Author(s):  
B. H. Al-Adhami ◽  
R. A. B. Nichols ◽  
J. R. Kusel ◽  
J. O'Grady ◽  
H. V. Smith
Keyword(s):  
Cryptosporidium Parvum ◽  
Immunofluorescence Microscopy ◽  
Uv Light ◽  
Fluorescein Isothiocyanate ◽  
Immunofluorescence Assay ◽  
Cryptosporidium Hominis ◽  
Specific Fluorescence ◽  
Thymine Dimers ◽  
Texas Red

ABSTRACT To investigate the effect of UV light on Cryptosporidium parvum and Cryptosporidium hominis oocysts in vitro, we exposed intact oocysts to 4-, 10-, 20-, and 40-mJ�cm−2 doses of UV irradiation. Thymine dimers were detected by immunofluorescence microscopy using a monoclonal antibody against cyclobutyl thymine dimers (anti-TDmAb). Dimer-specific fluorescence within sporozoite nuclei was confirmed by colocalization with the nuclear fluorogen 4′,6′-diamidino-2-phenylindole (DAPI). Oocyst walls were visualized using either commercial fluorescein isothiocyanate-labeled anti-Cryptosporidium oocyst antibodies (FITC-CmAb) or Texas Red-labeled anti-Cryptosporidium oocyst antibodies (TR-CmAb). The use of FITC-CmAb interfered with TD detection at doses below 40 mJ�cm−2. With the combination of anti-TDmAb, TR-CmAb, and DAPI, dimer-specific fluorescence was detected in sporozoite nuclei within oocysts exposed to 10 to 40 mJ�cm−2 of UV light. Similar results were obtained with C. hominis. C. parvum oocysts exposed to 10 to 40 mJ�cm−2 of UV light failed to infect neonatal mice, confirming that results of our anti-TD immunofluorescence assay paralleled the outcomes of our neonatal mouse infectivity assay. These results suggest that our immunofluorescence assay is suitable for detecting DNA damage in C. parvum and C. hominis oocysts induced following exposure to UV light.

Degradation of Pharmaceutical Pollutants under UV Light using TiO2 Nanomaterial Synthesized through Reverse Micelle Nanodomains

2021 ◽  
pp. 87-110
Keyword(s):  
Wastewater Treatment ◽  
Reverse Micelle ◽  
Uv Light ◽  
Sol Gel ◽  
Bet Surface Area ◽  
Tio2 Photocatalyst ◽  
Gel Method ◽  
Sol Gel Method ◽  
Treatment Techniques ◽  
Pharmaceutical Pollutants

Controlling water pollution are huge challenges throughout the world especially concerning pharmaceutical pollutants. Common practices at industrial wastewater treatment facilities need to be upgraded with advanced wastewater treatment techniques. TiO2 based photocatalytic processes have shown great potential for removal of these aqueous pharmaceutical pollutants. Reverse micelle based modified sol-gel method is utilized for the synthesis of TiO2 nanomaterial. Generated reverse micelle nanodomains have controlled size and particle size distribution (PSD) of synthesized TiO2 nanomaterial, as revealed by SEM and DLS analysis. Thermal behaviour of synthesized sample is characterized by TGA analysis. TiO2 photocatalyst is also characterized through XRD, BET surface area, and UV-Vis spectroscopy. TiO2 photocatalyst is used for degradation of three model pharmaceutical pollutants viz. Levofloxacin hemihydrate (LFX), Metronidazole (MNZ) and Ketorolac tromethamine (KRL) under a UV light source. Reverse micelle mediated modified sol-gel method synthesized TiO2 nanomaterial has shown excellent photocatalytical performance, where degradation efficiency of LFX, KRL and MNZ were found to be 99.6%, 98% and 91.4% respectively within a little as 60 minutes.

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