Photocatalytic Decolorization of Methylene Blue in Aqueous TiO₂ Suspension

Effect of temperature on methylene blue decolorization in aqueous medium in electrical discharge plasma reactor

“…Higher (60.7 kJ mol -1 ) and similar (14.45 kJ mol -1 ) activation energy values can be found in the literature for the photocatalytic/TiO 2 MB decolorization within different temperature ranges. 30,31 As stated by Ling et al, 32 the photocatalytic oxidation process does not require heating because it is initiated by photonic activation, and thus the activation energy may be close to zero. The authors concluded that the reported values ranging from 5 to 20 kJ mol -1 are very close to those of a hydroxyl radical reaction and suggested that organic compound decomposition through a photocatalytic reaction might be controlled by the hydroxyl radical reaction.…”

Effect of Particle Addition on Ultrasonic Degradation Reaction Rate

“…Figure 3 shows the effects of amount of TiO 2 or Al 2 O 3 particles addition on the enhancement of degradation of methylene blue at a frequency of 490 kHz and an ultrasonic power of 8 W. Here, k app and k app, 0 represents the apparent degradation rate constant and the apparent degradation rate constant in the absence of particles, respectively. The apparent degradation rate constant is proportional to the increase in amount of TiO 2 particle until amounts of particle is approximately 1.3 g. The optimal concentration of TiO 2 was 0.25 g/L in the photocatalytic irradiation system, because the UV light was hindered by the excess TiO 2 particles [23]. However, such a phenomenon is not observed in this ultrasonic irradiation system.…”

In situ hydrothermal synthesis of a novel hierarchically porous TS-1/modified-diatomite composite for methylene blue (MB) removal by the synergistic effect of adsorption and photocatalysis

“…TS-1 nanoparticles were coated in situ on the surface of a single diatom shell. The resulting TS-1/Dt composites possessed much higher specific area and micropore volume than the mechanical mixing samples of TS-1 and diatomite [32,[41][42][43], and also exhibited superior removal efficiency for MB (99.1% after 2 h) compared to pure TS-1 nanoparticles, and the conventional TiO 2 [62] and TiO 2 /diatomite photocatalyst [63], as simulated using a pseudofirst-order model. The outstanding dye removal performance of the TS-1/Dt composites was ascribed to their improved adsorption properties, which worked in conjunction with the subsequent UVphotocatalyzed reaction.…”

“…2 and Table 1. In comparison, the removal amount by TS-1/Dt 24 was almost three times higher than that of the conventional photocatalyst, TiO 2 (12.56 mg/g) [62], and much higher than that of the TiO 2 /diatomite composites (19.6 mg/g) [63]. This further underscores the excellent MB removal properties of the novelly synthesized composites via the combination of adsorption and photocatalysis.…”