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In this work, anionic RR4 dye was used to sensitize TiO2/PVA and TiO2/PEG immobilized system in enhancing photocatalytic degradation of cationic methylene blue (MB) dye. 0.3g of TiO2 and polymer binder was coated onto a clean glass plate by using brush technique to develop optimum immobilize TiO2 system. A comparison study between immobilized TiO2/PVA (Im/TiO2/PVA) and Immobilized TiO2/PEG (Im/TiO2/PEG) system with and without RR4 sensitizer were carried out under 45 W fluorescent lamp and visible light irradiation. The photocatalytic degradation of MB was significantly enhanced for both RR4 dye sensitized Im/TiO2/PVA and Im/TiO2/PEG with 1st order rate constant was ca. 0.035 and 0.030 min-1 respectively under 45-W fluorescent lamp. Same observation as well under visible light irradiation whereby enhanced of those RR4 sensitized immobilized photocatalysts were recorded as compared with immobilized photocatalysts without RR4 as sensitizer. The photocatalytic enhancement under Im/TiO2/PVA/RR4 and Im/TiO2/PEG/RR4 are due to the ability of RR4 dye to become electron (e-) donor for conduction band (CB) of TiO2, thus making TiO2 CB riches with electron, eventually this e- is used to remove MB by producing hydroxyl radical.

In this work, photocatalytic degradation of Reactive Red 4 (RR4) using immobilized P25 and kronos were performed under fluorescent light sources. The photocatalysis activity for both catalysts was investigated under fluorescent lamp source which consist UV and Visible light. The effect of various parameters such as initial concentration, initial pH and strenght of immobilized plate were studied. The result showed that 90% of RR4 dye was degrade in 1 hr using immobilized/kronos/DSAT at 100 mg L-1 of RR4 dye while 81% degradation was achieved by immobilized/P25/DSAT at the same condition. The lowest pH showed the higher photocatalytic activity. Hence, the effect of dye concentration and pH on the photocatalysis study can be related with the behavior of environmental pollution. The low strength showed by immobilized/P25/DSAT where it remain 37 % as compared with strength of immobilized/kronos/DSAT (52 wt.%). For the future work, the polymer binder like Polyvinyl alcohol (PVA), Polyethylene glycol (PEG), and others polymers can be apply in immobilized study to overcome the strength problem.

The study on TiO2 for wastewater remediation has gained interest among researchers. However, the application of this photocatalyst is limited due to non-recyclability of conventional TiO2. Thus, immobilization technique has been developed to solve this issue. Hence, a comparison study between two types of immobilized photocatalysts namely titanium dioxide (TiO2) and TiO2 mixed with polyvinyl alcohol (PVA) has been conducted in this work to observe the significant effect of PVA polymer in photocatalysis reaction of reactive red 4 (RR4) dye. Double sided adhesive tape (DSAT) was used as thin layer binder in this immobilization system. The result shows that the photocatalytic performance of TiO2-PVA/DSAT was higher than that of TiO2/DSAT under both normal UV and visible light irradiations due to the conjugated unsaturated polymer from PVA serve as electron donor for TiO2 thus increase the photocatalysis process. Besides, TiO2-PVA/DSAT was also found to possess much better adhesion strength to the support material compared to TiO2/DSAT. Based on the findings, this TiO2 immobilization system is expected to be beneficial in the industrial wastewater treatment. Thus, further study to improve the photocatalytic activity of this immobilized TiO2 will be in our future work.

Photocatalytic degradation rate of reactive red 4 (RR4) using carbon coated nitrogen doped TiO2 (C N co-doped TiO2) in photocatalysis process is main goal on this research. The main operating the parameters such as effect of initial dye concentration, catalyst loading, aeration flow rate and initial pH on degradation of RR4 under 45 W fluorescent lamp was investigated. photocatalytic activity of RR4 dye decreased with increasing RR4 dye concentration. The optimum loading is around 0.04 g and optimum aeration rate is about 25 mL min-1 of C N co-doped TiO2. Effect of pH was conducted based on the optimum loading and conclude that the photocatalytic degradation of RR4 became faster at pH 2 - 7. For the future work, the modification of doping with others element like non-metal or metal with C N co-doped TiO2 can be enhanced toward the higher efficieny of photodegradation under visible light. Moreover, the immobilized technique can be used in future to overcome the difficulty of filtration on suspension.

Novel photocatalysts of TiO2 and TiO2/PEG were immobilized using new technique which is double sided adhesive tape (DSAT) as a thin layer binder onto glass plate. The photocatalytic activity study of immobilized/TiO2 and immobilized/TiO2/PEG were carried out by irradiating of 36 mg L-1 MB dye in the presence of normal and visible light with rate of decolourization was estimated from aliquot concentration spectrophotometrically. The high photocatalytic activity from immobilized/TiO2/PEG was observed with the rate constants of ca 0.06 and 0.02 min-1 under normal and visible light irradiation respectively. An active photocatalytic activity was observed for immobilized/TiO2/PEG sample while no photocatalytic activity detected under immobilized/TiO2. The high photoactivity was also detected under normal light for immobilized/TiO2/PEG sample. This might be due to the presence of electron conjugate in PEG that acted as electron donor for TiO2 thus increase the photocatalysis process. Moreover, this electron donor is reported to be able to become active under low energy visible light hence the immobilized/TiO2/PEG can perfomed its photoactivity under visible light irradiation.

The study gives a general overview of the CFD-simulated gas flow via the nozzle of a De Laval rocket engine. In CFD software, the mesh is generated using the nozzle’s geometry. In this work, CFD methods are used to compare a number of factors with those derived from classical theory, such as pressure, velocity, temperature, and arear ratios. The results of computational modelling of CFD simulation are comparable to those found from theoretical calculations.

Carbon doped TiO2 (C-doped TiO2) photocatalyst was prepared by using polyethylene glycol (PEG) as carbon precursor under calcination process using muffle furnace. The modified C-doped was immobilized onto a glass plate by using brush and DSAT method with the optimum C-doped TiO2 was measured by the highest photoactivity detected from photodegradation of reactive red 4 (RR4) dye. The optimum condition of C-doped TiO2 denoted as C2 consist of 0.1 g of PEG in 6.5 g TiO2 was found where the photodegradation rate of C2 was ca 0.1545 min-1 and it is 2.5 times faster as compared with unmodified TiO2. The presence of C-C bond represented as carbon element was detected in all C-doped TiO2 samples analyzed by Fourier Transform Infrared (FTIR) spectra at 933 nm. No bandgap energy of C-doped TiO2 samples changes was recorded by UV-vis DRS spectroscopy, all C-doped TiO2 except C1 have shown higher photocatalyic activity as compared with unmodified TiO2 due to the presence of carbon in which acts as electron scavenger. No significant changes in term of surface morphology between C-doped TiO2 and unmodified TiO2 sample observed by SEM images. The C-doped TiO2 immobilized sample produces a fine surface with a smooth coating, excellent photodegradation of RR4 dye and can be used in wide range solar applications. [ABSTRACT FROM AUTHOR]