The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with TiO₂ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of TiO₂ photoelectrode were used. Thermal oxidation electrode (Th-TiO₂) was made by oxidation of titanium metal sheet; sol-gel electrode (SG-TiO₂) and powder electrode (P-TiO₂) were made by coating and then heating a layer of titania sol-gel and slurry TiO₂ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelectrodes and DSA electrodes is: Ru/Ti > Ti > SG-TiO₂ > Th-TiO₂. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. Na₂SO₄ and NaCl showed different decolirization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

The formation of ConTiOn+₂ compounds, i.e., CoTiO₃ and Co2TiO₄, in a 5 wt% CoOx/TiO2 catalyst after calcination at different temperatures has been characterized via scanning electron microscopy (SEM), Raman and X-ray photoelectron spectroscopy (XPS) measurements to verify our earlier model associated with Co3O4 nanoparticles present in the catalyst, and laboratory-synthesized ConTiOn+₂ chemicals have been employed to directly measure their activity profiles for CO oxidation at 100˚C. SEM measurements with the synthetic CoTiO₃ and Co2TiO₄ gave the respective tetragonal and rhombohedral morphology structures, in good agreement with the earlier XRD results. Weak Raman peaks at 239, 267 and 336 cm-1 appeared on 5 wt% CoOx/TiO₂ after calcination at 570oC but not on the catalyst calcined at 450˚C, and these peaks were observed for the ConTiOn+₂ compounds, particularly CoTiO3. All samples of the two cobalt titanate possessed O 1s XPS spectra comprised of strong peaks at 530.0±0.1 eV with a shoulder at a 532.2-eV binding energy. The O 1s structure at binding energies near 530.0 eV was shown for a sample of 5 wt% CoOx/TiO₂, irrespective to calcination temperature. The noticeable difference between the catalyst calcined at 450 and 570˚C is the 532.2 eV shoulder which was indicative of the formation of the ConTiOn+₂ compounds in the catalyst. No long-life activity maintenance of the synthetic ConTiOn+₂ compounds for CO oxidation at 100˚C was a good vehicle to strongly support the reason why the supported CoOx catalyst after calcination at 570˚C had been practically inactive for the oxidation reaction in our previous study; consequently, the earlier proposed model for the Co₃O₄ nanoparticles existing with the catalyst following calcination at different temperatures is very consistent with the characterization results and activity measurements with the cobalt titanates.

This study was investigated experimental condition which is able to evaluate photocatalytic activity of various commercial TiO₂. The experiments were performed for three representative substances (ethanol, phenol and methylene blue) and four kinds of commercial TiO₂, under the experimental conditions such as pH, reactant concentration, amount of TiO₂, reaction time and UV intensity. The optimum experimental conditions to evaluate photocatalytic activity were as follows : for ethanol, the initial concentration 1000 ppm, initial pH 8, TiO₂ loadings 0.1 wt%, and reaction time 90 minutes: for phenol, the initial concentration 200 ppm, initial pH 8, TiO₂loadings 1 wt%, and reaction time 60 minutes: for methylene blue, the initial concentration 200 ppm, initial pH 4, TiO₂ loadings 0.5 wt%, and reaction time 30 minutes.

The VOCs have a direct influence on indoor air pollution, and stimulate respiratory organs and eyes in human body. Also, most of VOCs are a carcinogenic substances and causes to SBS (sickness building syndrome). Therefore, this study was progressed in photocatalysis of VOCs using UV/TiO2 which was a benign process environmentally. The experiments were performed to know photodegradation characteristics as crystalline structure of TiO2 which had anatase, rutile and P-25 (anatase:rutile=70:30). The main purpose of this study was to identify photocatalytic characteristics as inlet concentration of reactants, H2O, and residence time.

Cobalt titanates (CoTiOx), such as CoTiO3 and Co2TiO4, have been synthesized via a solid-state reaction and characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) measurement techniques, prior to being used for continuous wet trichloroethylene (TCE) oxidation at 36℃, to support our earlier chemical structure model for Co species in 5 wt% CoOx/TiO2 (fresh) and (spent) catalysts. Each XRD pattern for the synthesized CoTiO3 and Co2TiO4 was very close to those obtained from the respective standard XRD data files. The two CoTiOx samples gave Co 2p XPS spectra consisting of very strong main peaks for Co 2p3/2 and 2p1/2 with corresponding satellite structures at higher binding energies. The Co 2p3/2 main structure appeared at 781.3 eV for the CoTiO3, and it was indicated at 781.1 eV with the Co2TiO4. Not only could these binding energy values be very similar to that exhibited for the 5 wt% CoOx/TiO2 (fresh), but the spin-orbit splitting (ΔE) had also no noticeable difference between the cobalt titanates and a sample of the fresh catalyst. Neither of all the CoTiOx samples were active for the wet TCE oxidation, as expected, but a sample of pure Co3O4 had a good activity for this reaction. The earlier proposed model for the surface CoOx species existing with the fresh and spent catalysts is very consistent with the XPS characterization and activity measurements for the cobalt titanates.

Small gas bubbles are used in many environmental and industrial processes for solid-liquid separations or to facilitate heat and mass transfer between phases. This study examines some of the factors that affect the bubble volume and size processed in the EF (electroflotation) process. The effect of electrode material, NaCl dosage, current and electrode distance were studied. The results showed that the generated bubble volume with electrode material lay in: Pt/Ti ≒ Ru/Ti ≒ Ir/Ti > Ti electrode. The more NaCl dosage was high, the smaller bubble was generated due to the low electric power. Bubble generation was increased with increase of current. With the increase of NaCl dosage, bubble generation was increased at same electric power (16.2 W). Generated bubble volume was not affected by electrode distance. However, no clear trends in bubble size as a function of these parameters were evident.

V2O5/TiO2 catalyst impregnated ceramic candle filters are in principle, capable of performing shallow-bed dust filtration plus a catalytic reaction, promoted by a catalytic deposited in their inner structure. Pilot-scale V2O5/TiO2 catalyst impregnated ceramic candle filters were prepared, characterized and tested for their activity towards the SCR reaction. The effect on NO conversion of operating temperature, gas hourly space velocity, amount of deposited catalyst, pressure drops and long-term experiment (life of catalytic filter) was determined. The following effects of V2O5/TiO2 catalyst impregnated ceramic candle filters in SCR reaction are observed: (1) It increases the activity and widens the temperature window for SCR. (2) When the content of V2O5 catalyst increases further from 3 to 9wt.%, activity of NO increases. (3) NO conversion at first increases with temperature and then decreases at high temperatures (above 400℃ over), possibly due to the occurrence of the ammonia oxidation reaction.

In this study, N doped TiO2 (TiO-N) thin film was prepared by DC magnetron sputtering method to show the photocatalytic activity in a visible range. Various gases (Ar, O2 and N2) were used and Ti target was impressed by 1.2 kW-5.8 kW power range. The hysteresis of TiO-N thin film as a function of discharge voltage wasn't observed in 1.2 and 2.9kW of applied power. Cross sections and surfaces of thin films by FE-SEM were tiny and dense particle sizes of both films with normal cylindrical structures. XRD pattern of TiO2 and TiO-N thin films was appeared by only anatase peak. Red shift in UV-Vis adsorption spectra was investigated TiO-N thin film. Photoactivity was evaluated by removal rate measurement of suncion yellow among reactive dyes. The photodegradation rate of TiO2 thin film on visible radiation was shown little efficiency but TiO-N was about 18%.

The phase transfer catalysis(PTC) reagent, ethyl tri-octyl ammonium bromide(ETABr), strongly catalyzes the reaction of p-nitrophenyl diphenyl phosphinate(p-NPDPIN) with benzimidazole(BI) and its anion(BI⊖). In ETABr solutions, the dephosphorylation reactions exhibit higher first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the substrate(p-NPDPIN), whereas the reaction of p-NPDPIN with OH⊖ is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is referred as 'aggregation complex model' for reaction of hydrophobic organic phosphinates with benzimidazole(BI) in hydrophobic quarternary ammonium salt(ETABr) solutions.