ZnO Photocatalysis Using Solar Energy for the Removal of Trace Amounts of Alfa-Methylstyrene, Diquat and Indigo Carmine from Water

2014 ◽  
Vol 17 (2) ◽  
Author(s):  
O. M. Shibin ◽  
B. Rajeev ◽  
V. Veena ◽  
E. P. Yesodharan ◽  
Yesodharan Suguna
Keyword(s):  
Visible Light ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Indigo Carmine ◽  
Parent Compound ◽  
Oxygen Demand ◽  
Solar Photocatalyst ◽  
Significant Chemical ◽  
Trace Pollutants

AbstractSemiconductor photocatalysis using ZnO has been extensively investigated for the chemical and bacterial decontamination of water and air. In most of these cases, UV light is the source of energy and visible light induced photocatalytic degradation of trace pollutants in water has not received adequate attention. In the present study, ZnO is evaluated as a solar photocatalyst for the removal of trace amounts of three typical pollutants, i.e. alpha- Methylstyrene (AMS, a petrochemical), Diquat (herbicide) and Indigo carmine (IC, a dye) from water. Degradation by itself does not result in complete mineralisation and decontamination as seen from the significant Chemical Oxygen Demand even after the parent compound has disappeared. However, the intermediates also get mineralized eventually. The study indicates that solar photocatalysis can be used as a viable tool for the purification water contaminated with these chemicals. The degradation follows variable kinetics depending on the concentration of the substrates. H

Solar photocatalysis mediated by ZnO for the removal of last traces of Indigo carmine dye pollutant from water

2018 ◽  
Vol 4 (02) ◽  
Author(s):  
Veena Vijayan ◽  
Suguna Yesodharan ◽  
E. P. Yesodharan
Keyword(s):  
Indigo Carmine ◽  
Parent Compound ◽  
Oxygen Demand ◽  
Green Technology ◽  
Solar Photocatalysis ◽  
Reaction Proceeds ◽  
Transient Intermediates ◽  
Significant Chemical ◽  
Hydroxyl Free Radicals ◽  
Purification Of Water

Solar photocatalysis as a potential green technology for the removal of traces of the dye pollutant Indigo carmine (IC) from water is investigated using ZnO as the catalyst. Degradation/decolorization alone does not result in complete decontamination as seen from the significant Chemical Oxygen Demand (COD) of water even after the parent compound has disappeared completely. The degradation proceeds through many intermediates which also get mineralized eventually but slowly. Oxalic acid is identified as a stable slow mineralizing degradation product which itself is formed from other transient intermediates. Effect of various parameters such as catalyst dosage, concentration of the dye, pH, temperature, presence of contaminant salts etc. on the degradation is investigated and quantified. Oxidants such as S2O82- and H2O2 have only moderate influence on the degradation. The degradation follows variable kinetics depending on the concentration of the substrate. The reaction proceeds very slowly in the absence of O2 indicating the importance of reactive oxygen species and hydroxyl free radicals in photocatalysis. H2O2 formed insitu in the system undergoes concurrent decomposition resulting in stabilization in its concentration. The study demonstrates that solar photocatalysis can be used as a viable tool for the purification of water contaminated with traces of IC.

scholarly journals TiO2 BEADS FOR PHOTOCATALYTIC DEGRADATION OF HUMIC ACID IN PEAT WATER

2011 ◽  
Vol 11 (3) ◽  
pp. 253-257 ◽  
Author(s):  
Winarti Andayani ◽  
Agustin N M Bagyo
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Oxalic Acid ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Color Intensity ◽  
Before And After

Degradation of humic acid in aqueous solution containing TiO2 coated on ceramics beads under irradiation of 254 nm UV light has been conducted in batch reactor. The aim of this experiment was to study photocatalytic degradation of humic acid in peat water. The irradiation of the humic acid in aqueous solution was conducted in various conditions i.e solely uv, in the presence of TiO2-slurry and TiO2 beads. The color intensity, humic acid residue, conductivity and COD (chemical oxygen demand) of the solution were analyzed before and after irradiation.  The compounds produced during photodegradation were identified using HPLC. The results showed that after photocatalytic degradation, the color intensity and the COD value of the solution decreased, while the conductivity of water increased indicating mineralization of the peat water occurred. In addition, oxalic acid as the product of degradation was observed.

scholarly journals WO3/W Nanopores Sensor for Chemical Oxygen Demand (COD) Determination under Visible Light

Sensors ◽  
2014 ◽  
Vol 14 (6) ◽  
pp. 10680-10690 ◽  
Author(s):  
Xuejin Li ◽  
Jing Bai ◽  
Qiang Liu ◽  
Jianyong Li ◽  
Baoxue Zhou
Keyword(s):  
Visible Light ◽  
Chemical Oxygen Demand ◽  
Oxygen Demand

Nanoengineered CdSe quantum dot–montmorillonite composites: an efficient photocatalyst under visible light irradiation

RSC Advances ◽  
2014 ◽  
Vol 4 (68) ◽  
pp. 35997-36005 ◽  
Author(s):  
Rajeev C. Chikate ◽  
Brijesh S. Kadu ◽  
Madhura A. Damle
Keyword(s):  
Quantum Dot ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Self Assembly ◽  
Indigo Carmine ◽  
Light Irradiation ◽  
Uniform Dispersion ◽  
Cdse Quantum Dot

Intercalated CdSe–CTAB–MMT nanocomposites with uniform dispersion of CdSe QD's are fabricated by a facile self-assembly approach that significantly enhances visible light induced photocatalytic degradation of Indigo Carmine.

scholarly journals Photocatalytic Degradation of Polynitrophenols on Various Commercial Suspended or Deposited Titania Catalysts Using Artificial and Solar Light

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Hinda Lachheb ◽  
Ammar Houas ◽  
Jean-Marie Herrmann
Keyword(s):  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Degradation Rate ◽  
Oxygen Demand ◽  
Solar Light ◽  
Test Reactions ◽  
Anionic Species ◽  
Paper Fibers ◽  
Purification Of Water

Phenol (PH) and three polynitrophenols (4-nitrophenol (PNP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP)) were photocatalytically degraded by using titania under either artificial or solar light. These four reactions were chosen as test reactions to compare the efficiencies of two suspended commercial titania photocatalysts (Degussa P-25 and Millennium PC-500). It appears that P-25 has a higher initial efficiency in all nitrophenol disappearance reactions. However, for the overall degradation rate, measured by the chemical oxygen demand (COD) disappearance, the performance of PC-500 was similar to that of P25. This was attributed to a favorable textural effect since PC-500 has a much higher surface area which facilitates the readsorption of intermediates. PC-500 was subsequently supported on a special photoinert paper provided by Ahlstrom Company (38-Pont Evèque, France). The influence of the silica binder used for sticking titania particles on the paper fibers was put in evidence as an inhibitor of the coulombic adsorption of anionic species, especially 2,4,6-trinitrophenol, because of the low pzc of silica. Once validated, this supported photocatalyst was introduced in an autonomous solar pilot photoreactor identical to the several prototypes built in the European AQUACAT program. It was demonstrated that the purification of water could be efficiently obtained in a larger scale without any final tedious filtration.

scholarly journals Direct photolysis and photocatalytic degradation of 2-amino-5-chloropyridine

2003 ◽  
Vol 68 (12) ◽  
pp. 961-970 ◽  
Author(s):  
Biljana Abramovic ◽  
Vesna Anderluh ◽  
Andjelka Topalov ◽  
Ferenc Gaal
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Parent Compound ◽  
Analytical Techniques ◽  
Direct Photolysis ◽  
Pyridine Moiety ◽  
Initial Substrate ◽  
Zero Order Reaction ◽  
Degradation Reaction

The direct photolysis and photocatalytic degradation of a pyridine pesticide analogue, 2-amino-5-chloropyridine, were investigated employing different analytical techniques ? potentiometry, for monitoring the pH and chloride genera- tion, spectrophotometry, for studying the degradation of the pyridine moiety, ion chromatography, for monitoring nitrate formation, and total organic carbon analysis for investigating the efficiency of the process. The photocatalytic degradation was studied in aqueous suspensions of titanium dioxide under illumination by UV light. It was found that chloride evolution was a zero-order reaction which takes place by direct photolysis, in that way differing from the degradation of the pyridine moiety, which takes place in the presence of titanium dioxide. Changes in pH during degradation indicate the formation of acidic intermediates and nitrate in addition to chloride. The effect of the initial substrate concentration was also investigated by monitoring the reaction of chloride generation as well as the degradation reaction of the pyridine moiety. It was found that degradation of the parent compound (2.5 mmol/dm3) by direct photolysis is completed in about 20 minutes, and of the pyridine moety by photocatalytic degradation in about nine hours. Based on the obtained data a possible reaction mechanism is proposed.

scholarly journals Visible Light Induced Photocatalytic Degradation of Methyl Red with Codoped Titania

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Susmitha Thota ◽  
Siva Rao Tirukkovalluri ◽  
Sreedhar Bojja
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Anatase Phase ◽  
Sol Gel ◽  
Visible Region ◽  
Oxygen Demand ◽  
Analytical Techniques ◽  
Active Species ◽  
Methyl Red ◽  
X Ray

Photocatalysis using semiconductor oxides was being investigated extensively for the degradation of dyes in effluent water. This paper reports our findings on visible light induced photocatalytic degradation of azo dye, methyl red mediated nitrogen and manganese codoped nano-titanium dioxide (N/Mn-TiO2). The codoped samples with varying weight percentages were synthesized by sol-gel method and characterized by various analytical techniques. The X-ray diffraction data showed that the synthesized samples were in anatase phase with 2θ at 25.3°. UV-visible diffuse reflectance spectral analysis revealed that the presence of dopants in TiO2 caused a significant absorption shift towards visible region and their presence was confirmed by X-ray photoelectron spectral data. The release of hydroxyl radical (major active species in photocatalytic degradation) by the photocatalyst in aqueous solution under visible light irradiation was quantitatively investigated by the photoluminiscent technique (PL). The effect of various experimental parameters like dopant concentration, pH, catalyst dosage, and initial dye concentrations was investigated and optimum conditions were established. The extent of mineralization of methyl red was studied by chemical oxygen demand (COD) assays and the results showed complete mineralization of the dye.

scholarly journals Visible light photoelectrochemical properties of a hydrogenated TiO2 nanorod film and its application in the detection of chemical oxygen demand

RSC Advances ◽  
2015 ◽  
Vol 5 (93) ◽  
pp. 76315-76320 ◽  
Author(s):  
Xiujie Wang ◽  
Shengsen Zhang ◽  
Hongjuan Wang ◽  
Hao Yu ◽  
Haihui Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Chemical Oxygen Demand ◽  
Oxygen Demand ◽  
Good Stability ◽  
Photoelectrochemical Properties ◽  
Nanorod Arrays ◽  
Tio2 Nanorod ◽  
Photoelectrochemical Sensor

Hydrogenated TiO2 nanorod arrays as a photoelectrochemical sensor exhibit good stability and reproducibility for online COD monitoring using visible light.

scholarly journals PHOTOCATALYTIC DEGRADATION OF PARAQUAT USING N-TiO2/SiO2 UNDER VISIBLE LIGHT

2018 ◽  
Vol 55 (4C) ◽  
pp. 277 ◽  
Author(s):  
Nguyen Thi Phuong Mai
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Organic Pollutant ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Illumination Time ◽  
X Ray

In the present paper, photocatalytic degradation of paraquat using N-TiO2/SiO2 with different molar ratio of titanium: nitrogen (Ti:N) under visible light was investigated. The catalyst was prepared via immersed SiO2 in N-TiO2. N-TiO2 was synthesized by sol-gel method.  The N-TiO2/SiO2 catalyst was characterized using X-ray diffraction, UV diffuse reflectance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy. The results from characterizations indicated that N-doped anatase TiO2 had a 20-25 nm size. Degradation of paraquat, at an initial concentration of 10 mg/L was determined by UV-Vis. Chemical oxygen demand (COD) was used for process performance. Based on the COD tests, the COD values in residual paraquat was lower than that in initial paraquat concentration after 8 hours illumination of visible light. Moreover, the experiment’s results indicated that 80% of paraquat was degraded within 8 h of illumination time. These results showed that N-TiO2/SiO2 with molar Ti:N=2:1 gives the highest degradation efficiency of paraquat under visible light. This catalyst was stable and reusable suggesting it can be applied to treat organic pollutant in water. 

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