Influence of operational parameters on the TiO₂ photocatalytic degradation of Methylene blue

Abstract

Thin films of titanium oxide were obtained by dip-coating, using the sol-gel method. TiO 2 powder (Degussa, P25) and polyethylene glycol (PEG) were added to enhance the photocatalytic properties of resulting films. Effects of experimental variables on the photocatalytic properties of the coatings were evaluated based on the degradation efficiency of the reference dye (Methylene blue). The photocatalytic activity of resulting TiO 2 coatings was improved with the loading of TiO 2 powder (Degussa, P25) and PEG in the sols. The electron-hole pair photogeneration increases with the energy of irradiation and improves photocatalytic efficiency. Increasing coating thickness leads to a rough surface with more reaction sites. Photodegradation conversion of Methylene blue (Mb) decreases with an increase in the initial concentration of Mb.

Microstructure and properties of in-situ prepared cellulosic biomass carbon based diatomite composite

“…The kinetic models of MB adsorption onto the 15-DT-CMC composite are shown in Figure 4(c,d). Comparing the values of the correlation coefficients of the pseudo-first-order and pseudo-second-order kinetic model, the R 2 value ( R 2 2 =0.999) for the pseudo-second-order kinetic model ( k 2 = 0.05017 g/mg min, q 2 =155.52 mg/g) is clearly higher than the R 1 ( R 1 2 =0.965) value for the pseudo-first-order kinetic model ( k 1 =1.995 min −1 , q 1 =152.119 mg/g) [32]. The greater correlation coefficient (more than 0.99) indicates the applicability of the pseudo-second-order kinetic equation, and suggests that the adsorption mechanism of MB onto the 15-DT-CMC composite might be a chemisorption process [33,34].…”

Hydrothermally fabricated surfactant-free CuxAg1−xS composites with enhanced photocatalytic activity and stability

“…Since last two decades, extensive attempts have been made in the direction of development of more capable and strong photocatalysts working under the UV sector of electromagnetic radiation intended for the degradation of pollutant species into the harmless compounds in the process of wastewater treatment. In the process of degradation of pollutants, the various oxides [2,3], sulphides [4,5], and oxynitride [6,7] semiconductor photocatalysts have been developed. Compared to oxides and oxynitrides, most of the metal sulphides have narrow band gaps and suitable band edge positions, implying that they are good candidates for UV light-driven photocatalysts.…”