Sensitizing Zinc Oxide Photocatalyst with Natural dye for Water Disinfection under Sun Light
Date
2011-06-01
Authors
Sondos Ateeq
Ahed Zyoud
Majdi Dweikat
Hikmat S. Hilal
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
<p>Several procedures are commonly used for water disinfection from bacteria. Examplesare chlorination, peroxide addition, ozonation and UV irradiation. Photodegradation ofmicroorganisms has also been examined. TiO2 and ZnO were examined by researchers forinactivation of Escherichia coli and some other types of bacteria using photo-degradationtechniques.ZnO is a wide band gap (3.2 ev) semiconductor, with limited photo-catalytic applications toshorter wavelengths only, and demands UV region for excitation. However, it has attractedattention as an interesting alternative to TiO2 in dye sensitized solar cells. ZnO has theadvantage of being sensitive to solar UV light.Because only about 4% of the solar spectrum falls in the UV region, ZnO semiconductoris sensitized by dye molecules. Sensitized ZnO catalysts have been investigated for organicpollutant degradation in a safe and simple manner.In this work, ZnO semiconductor nano-particles, combined with safe low cost sensitizer(natural dye anthocyanin) was used to disinfect water from bacteria by photodegrading itwith solar simulator light. The natural dye sensitized ZnO to the visible light, as the dye hassmaller band gap and absorbs in the visible region.Illumination has been constructed by a solar simulator lamp. A pre-contaminated watersample with E-Coli bacteria was treated with the catalyst (ZnO/anthocyanin) under halogenspot lamp. A noticeable decline in bacteria concentration was observed. Contaminatedsamples were treated with naked ZnO, anthocyanin dye, and light source (without anyadditions) separately in control experiments.Up to 90% degradation was achieved by the ZnO/anthocyanin catalyst system undersolar light in 90 minutes. Effect of different parameters on reaction rate and efficiency, suchas temperature, pH, concentration and others were also studied and will be presented.</p>
<p>Several procedures are commonly used for water disinfection from bacteria. Examplesare chlorination, peroxide addition, ozonation and UV irradiation. Photodegradation ofmicroorganisms has also been examined. TiO2 and ZnO were examined by researchers forinactivation of Escherichia coli and some other types of bacteria using photo-degradationtechniques.ZnO is a wide band gap (3.2 ev) semiconductor, with limited photo-catalytic applications toshorter wavelengths only, and demands UV region for excitation. However, it has attractedattention as an interesting alternative to TiO2 in dye sensitized solar cells. ZnO has theadvantage of being sensitive to solar UV light.Because only about 4% of the solar spectrum falls in the UV region, ZnO semiconductoris sensitized by dye molecules. Sensitized ZnO catalysts have been investigated for organicpollutant degradation in a safe and simple manner.In this work, ZnO semiconductor nano-particles, combined with safe low cost sensitizer(natural dye anthocyanin) was used to disinfect water from bacteria by photodegrading itwith solar simulator light. The natural dye sensitized ZnO to the visible light, as the dye hassmaller band gap and absorbs in the visible region.Illumination has been constructed by a solar simulator lamp. A pre-contaminated watersample with E-Coli bacteria was treated with the catalyst (ZnO/anthocyanin) under halogenspot lamp. A noticeable decline in bacteria concentration was observed. Contaminatedsamples were treated with naked ZnO, anthocyanin dye, and light source (without anyadditions) separately in control experiments.Up to 90% degradation was achieved by the ZnO/anthocyanin catalyst system undersolar light in 90 minutes. Effect of different parameters on reaction rate and efficiency, suchas temperature, pH, concentration and others were also studied and will be presented.</p>
<p>Several procedures are commonly used for water disinfection from bacteria. Examplesare chlorination, peroxide addition, ozonation and UV irradiation. Photodegradation ofmicroorganisms has also been examined. TiO2 and ZnO were examined by researchers forinactivation of Escherichia coli and some other types of bacteria using photo-degradationtechniques.ZnO is a wide band gap (3.2 ev) semiconductor, with limited photo-catalytic applications toshorter wavelengths only, and demands UV region for excitation. However, it has attractedattention as an interesting alternative to TiO2 in dye sensitized solar cells. ZnO has theadvantage of being sensitive to solar UV light.Because only about 4% of the solar spectrum falls in the UV region, ZnO semiconductoris sensitized by dye molecules. Sensitized ZnO catalysts have been investigated for organicpollutant degradation in a safe and simple manner.In this work, ZnO semiconductor nano-particles, combined with safe low cost sensitizer(natural dye anthocyanin) was used to disinfect water from bacteria by photodegrading itwith solar simulator light. The natural dye sensitized ZnO to the visible light, as the dye hassmaller band gap and absorbs in the visible region.Illumination has been constructed by a solar simulator lamp. A pre-contaminated watersample with E-Coli bacteria was treated with the catalyst (ZnO/anthocyanin) under halogenspot lamp. A noticeable decline in bacteria concentration was observed. Contaminatedsamples were treated with naked ZnO, anthocyanin dye, and light source (without anyadditions) separately in control experiments.Up to 90% degradation was achieved by the ZnO/anthocyanin catalyst system undersolar light in 90 minutes. Effect of different parameters on reaction rate and efficiency, suchas temperature, pH, concentration and others were also studied and will be presented.</p>