Suyog A. Soni, Vikram R. Jadhav and Tushar A. Kere
Calcination, Photocatalytic Activity, IR, FTIR
|PUBLISHED DATE||06 September 2018|
|PUBLISHER||The Author(s) 2018. This article is published with open access at www.chitkara.edu.in/publications|
A successful series of CuxZn1-xO (variable x = 0.05, 0.1, 0.15 and 0.2) were characterized by thermogravimetric (TG-DTA), Fourier Transform Infra-Red (FTIR) spectroscopy, and X-ray Diffraction (XRD) techniques. The photocatalytic activity of prepared samples was accurately assessed by the photocatalytic decomposition of LASER dye in an aqueous solution under irradiation of solar light and was compared favourably to non-dope commercially available ZnO photo-catalyst. The effect of various parameters like the amount of a catalyst, the calcination temperature on photocatalytic activity is also studied. The direct effect of various photosensitizing salts like NaCl, Na2CO3, and Na2S2O3 on photocatalytic activity of ZnO and Cu0.05Zn0.95O was carefully studied.
Photocatalytic treatment of chemical pollutants using semiconductors as the photocatalyst has been important method among advanced reaction techniques. Many published studies precisely on the photocatalytic activity of a semiconductors like TiO2. TiO2 and most of the other photo-catalysts can barely respond to UV irradiation  that takes up 4% of solar energy, which limits the practical application of photo-catalysts to broad extent. Since direct sunlight typically contains favorably nothing but 4% of Ultra-Violet (UV) light as compared to visible light which is 43% of unlimited solar energy hence use of TiO2 is largely impaired . In recent years ZnO shows its unique applications in the optics, opto electronics, catalysis, pyro-electricity, and piezo-electricity. ZnO is one of the important photo-catalyst because of its unique and novel advantages, like non-toxicity, minimum price, and high photocatalytic activity . However, the disadvantages of this catalyst is that its catalytic activity is still not enough for the commercial applications. An effective and practical approach to improve the photocatalytic activity is doping by adding some hetero elements, through the presence of doping metal ions in the ZnO crystalline matrix significantly affects the photocatalytic activity charge carrier recombination rate and interfacial electron-transfer rate . Extensively speaking the metal ions used as a dopant are often the transition metal ions e.g., Co2+, Mn2+, Mn4+ etc. . In the past several years, semiconductors of ZnO doped with narrow-band-gap metals , including Fe, W, Cd and Ga have been reported. Rhodamine as shown in figure no. 1.Fluorescein, coumarin, stilbene, umbelliferone, tetracene, malachite green and many other dyes are commonly used as LASER dye.
The removal of LASER dye pollutants in waste water is an important measure in environment protection. Convention waste water treatment such as chemical, physical, biological process are not always suitable for treating moderate to high concentration waste water. Advanced Oxidation Process (AOPs) are alternative techniques for destruction of toxic compounds and many other dyestuff organics in waste water. The overall benefits of the delocalization of textile industrial waste water includes saving a huge amount of water, because textile industries, LASER dye industries are regarded as chemical intensive and water intensive. The decolorized effluent may be recycled in same industry and other applications like agriculture, other industries that required a less quality water, especially the suffer countries with water deficiency .
|ISSN||Print : 2349-7564, Online : 2349-7769|
The copper doped zinc oxides (CuxZn1-xO; where x = 0.05, 0.1, 0.15, 0.2) was synthesized by co-precipitation method. The doping was confirmed by XRD and FTIR studies. The photocatalytic degradation of LASER dye solution using CuxZn1-xO (where x = 0.05, 0.1, 0.15, 0.2) photo-catalyst showed that Cu0.05Zn0.95O shows better activity than other synthesized catalyst. The photocatalytic degradation of LASER dye solution using Cu0.05Zn0.95O photo-catalyst calcined at various temperature (400, 500 and 600 o C) showed sample calcined at 600 o C shows maximum efficiency. It is also found that the different photosensitizers shows different effect on photocatalytic degradation efficiency. NaCl and Na2CO3 shows positive effect, while Na2S2O3 shows negative effect. As amount of photosensitizer increases photocatalytic property of NaCl and Na2CO3 increases and photocatalytic property of Na2S2O3 decreases. Among the all photo-sensitizers Na2CO3 is act best photo-sensitizer for both ZnO and Cu0.05Zn0.95O.