Kinetics of Photocatalytic Decomposition of Methylene Blue

Abstract

To treat dyeing and finishing industrial wastewater effluents by an advanced oxidation process, the decomposition kinetics of methylene blue by nanofine sol TiO 2 /UV was systematically studied in two batch slurry reactors. The factors of study include agitation speed, recirculation flow rate, initial dissolved oxygen concentration, initial methylene blue concentration, reaction temperature, TiO 2 dosage, and UV light intensity. By using the network reduction technique, the general rate equation has been developed from considering the reaction mechanism. The rate equation uses a systematic reaction network reduction technique to avoid the need of more restrictive assumptions commonly used, such as a rate-determining step or equilibrium steps. The resulting rate equation is applicable to a wider range of reaction conditions. After applying the resulting rate equation to predict the transient concentrations of other dye compounds, we expect it can be applied for the kinetics of photodecomposition of other organic compounds.

Photocatalytic Behavior of Water-Based Styrene-Acrylic Coatings Containing TiO2 Sensitized with Metal-Phthalocyanine Tetracarboxylic Acids

“…As was reported by other authors [43], MB decomposition rate usually increases with the photocatalyst concentration up to a limit. In the case of the coatings containing P25-MnPcTC, as it can be observed from Figure 6c, the rate of MB photodecomposition is influenced by the catalyst concentration.…”

Synthesis, optical, photocatalytic, and electrochemical studies on Ag2S/ZnS and ZnS/Ag2S nanocomposites

“…The control over nanoparticle size, size distribution, and dispersity is very important for the synthesis of high-performance nanocomposites. Different combinations of metal oxides and metal sulfide have been extensively examined as potential photocatalysts for the degradation of organic dyes (Reddy et al 2007;Wu and Chern 2006). Heterogeneous photocatalysis is a good method for the decontamination and mineralization of organic pollutants because of its high efficiency, low-energy consumption, and satisfactory environmental compatibility (Su et al 2008;Ž ukauskas et al 2010).…”

Fabrication of Photocatalyst Composite Coatings of Cr-TiO2 by Mechanical Coating Technique and Oxidation Process

“…When changing the oxidation temperature (Figure 7b) or the oxidation time (Figure 7c), the photocatalytic activity firstly increases, then decreases, when adding a higher content of Cr. The MB-occupied accessible surface area of TiO2 coatings is excited to generate hydroxyl radical and superoxide radical that both decomposed the adsorbed MB solution [33,34]. The structurally-defective morphology of Cr-TiO2 coatings is affected with adding Cr, as reported by references [35,36].…”