Experimental Study of Influencing Factors and Kinetics in Catalytic Removal of Methylene Blue with TiO2 Nanopowder

Abstract

In this research, degradation of methylene blue as a dye pollutant was investigated in the presence of TiO 2 nanopowders using photolysis and sonolysis systems separately and simultaneously. Effect of different parameters such as catalyst dosage, initial concentration of dye, UV power, pH and type of catalyst on the removal efficiency was ascertained. The results showed that basic pH is proper for the photocatalytic removal of the dye. Furthermore higher UV power and lower initial concentration of dye leads to higher removal percent. Moreover TiO 2 showed more photocatalytic activity than ZnO in the nanopowder form. The experimental kinetic data followed the pseudo-first order model in both photocatlytic and sonophotocatalytic processes but the rate constant of sonophotocatalysis is higher than it at photocatalysis process. Finally the reaction order of the rate law respect to nanocatalyst dosage in photocatalysis process is obtained 1.45. High activation energy of this process shows its high sensitivity to temperature.

141 Induction Heating of TiO 2 Coating on SS Substrate for Photocatalysis 2016 60 3 Induction Heating Consolidation of TiO 2 Sol-Gel Coating on Stainless Steel Support for Photocatalysis Applications

“…11. The MB solution without a catalyst exhibited a slight UV light degradation, as reported in the literature for this type of azo dye [31][32][33]. Therefore, this does not affect the performance of the photocatalysts and it may be negligible.…”

“…The pH of the solution was set to 10, which previous studies [31][32][33] report to be the best condition for achieving higher methylene blue degradation due to the high TiO 2 adsorption. This adsorption is promoted by a negative charge on the catalyst surface, which is obtained in a basic medium [31,33,34]. Regarding the adsorption-desorption equilibrium of methylene blue on the photocatalysts, the first solution sample was obtained after 2 h in the dark and the UV illumination of the systems began.…”

Influence of Dissolved Ions on the Water Purification Performance of TiO2-Impregnated Porous Silica Tubes

“…• concentrations [10]. However, in this study, it appeared that the reaction rate constant did not exhibit a large decrease even at high methylene blue concentrations, likely due to the water passing through the tube forming a thin film, which subsequently underwent UV irradiation.…”

Investigating the Water Sealing Capability of Polymer Concrete

“…The high efficiency of the FeCl 2 as catalyst could be due to the high solubility of this catalyst with respect to Fe 2 O 3 NWs. The photocatalytic activity was quantitatively evaluated by calculating the pseudo first-order rate constants (k) according to the following equation (Wang et al, 2006;Asiri et al, 2011;Salehi et al, 2012):…”

“…In the boom of the eco-conservation and the eco-friendly techniques to degrade the pollutants in water and wastewater, the Advance Oxidation Processes or AOPs are seen as alternative techniques (Gupta et al, 2004) to the traditional processes. The AOPs use chemical procedures based on the use of catalysts or photochemical compounds which generate highly reactive transient species as the hydroxyl radical which possesses high efficiency for the oxidation of organic compounds (Marin et al, 2007;Mohabansi et al, 2011;Salehi et al, 2012;Samet et al, 2012). AOPs have many advantages such as complete mineralization of the pollutant, are non-selective processes, are used in low concentration of contaminants and can be combined with other methods (Garriga I Cabo, 2007).…”