Abstract
One of the environmental issues is water Pollution causing serious health related problem not only to human but also seriously affect aquatic life. Dyes are among the pollutants that pollute our water bodies. In the olden days so many methods were applied for the purification of water but recently photocatalysis shown a promising technique where the pollutants (dyes) were degraded to give clean water and carbon dioxide to be liberated as the end product. The specific surface area of the photocatalyst 243.80 m2g-1 and the PZC was found to be 8.10. Only 0.9% of the dye (MG) decolorized in the presence of light (photolysis) while 25% of the MG was adsorbs in the dark with 30 minutes of contact. The ANOVA showed an F-value of 1114.81 which suggests that the model is significant. All model terms i.e. MG initial concentration, photocatalyst dose, irradiation period and pH are all significant with Prob>” values <0.05. The predicted R-squared that has a value 0.995 was in perfect agreement reasonably with Adj R-squared that reached up to 99.8%. Adequate precision more than 4.00 by this model indicates desirable and adequate signal. The influence of MG initial concentration in removing the MG color was higher when compared to other parameters involved and this was indicated by the F-values.
Highlights
Photocatalytic decolorization of dyes using TiO2 has been studied in the past by various researchers (Behnajady et al, 2007)
Malachite green dye (MG) with molecular formula C32H16N8S2O6CuNa2 is among the most persistent compared to acidic dye, disperse dye and reactive dye especially when it was used during photocatalysis with a TiO2 (Gallo et al, 2008)
Advance Oxidation Process means that very reactive species were generated especially hydroxyl radicals and this radical usually oxidizes most of pollutants very fast and it was non-selective. (Uygur, 1997) removed azo dyes using Advance Oxidation Process. (Aplin and Waite, 2000) used this same process in photo- Fenton reaction of hydrogen peroxide, Fe2+ /H2O2 while (Moraes et al, 2000) applied UV in the photocatalysis of hydrogen peroxide, H2O2/UV and (Masten and Davies, 1994) used TiO2/UV in decomposing hydrogen peroxide
Summary
Photocatalytic decolorization of dyes using TiO2 has been studied in the past by various researchers (Behnajady et al, 2007). The process variables studied were: initial MG dye concentration (A), photocatalyst dosage (B), irradiation time (C) and the initial pH (D) This method is used in optimizing variables and the variables were considered as independent parameters while decolorization as output response variable. The surface area according to this method was calculated from below equation: Where V is the volume of the base required to raise the pH of the sample from 3- 9. This volume was measured in replicate and the average value was taken for the surface area calculation. The photocatalyst produced was characterized for its specific surface area using sear’s Method, Point of zero charge (PZC)
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