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Photocatalysis as an eco-friendly technology has the potential to achieve the Sustainable Development Goals (SDGs). However, an improvement of conventional photocatalysts is necessary to overcome their limitations such as slow kinetics, wavelength for excitation, and environmental restrictions. In particular, the development of a photocatalyst that can operate even in the absence of light is constantly conducted, and a photo-chargeable photocatalyst could be one of the answers. In this paper, a heterojunction composed of TiO2 and NiO-TiO2 bilayer film photocatalyst (BLF) was prepared. The effect of the synthesis conditions of the NiO-TiO2 layer on the photocatalytic properties was investigated. Photocatalytic degradation measurements were conducted with an acid orange 7 (AO7) solution under light and dark conditions. The highest degradation BLF was synthesized at a NiO loading of 52% and calcination temperature of 300 °C. The prepared sample showed about five-fold greater photocatalytic activity of 48% in AO7 degradation after 8 h compared to an ordinary TiO2 film (9%) under light conditions. Moreover, under dark conditions it exhibited 13.6% degradation, while the naked layers of TiO2 and NiO-TiO2 showed no degradation. The proposed mechanism suggested that photocatalysis in the dark was possible due to the stabilization of photogenerated holes by anionic intercalation during illumination. [ABSTRACT FROM AUTHOR]

Methane gas storage and transportation via clathrate hydrates is proposed to be a potential solution for large-scale energy storage. In this work, we study the formation and decomposition kinetics of methane hydrates (MH) in a laboratory-scale unstirred crystallizer. The present investigation demonstrates comparative studies of hydrate formation and dissociation kinetics in the presence of tetrahydrofuran (55.6 and 27.8 mmol/mol, 5.56 and 2.78 mol % THF) and sodium dodecyl sulphate (1 mg/g, 0.1 wt% SDS). Moreover, the storage capacity and hydrate formation kinetics in both the systems are discussed. In a recent work, enhanced methane hydrate growth in the presence of THF at close to atmospheric conditions was demonstrated. The emphasis of the current work is to study the stability of hydrates to understand dissociation kinetics by measuring the rate of hydrate decomposition at different temperatures. Hydrate stability measurements were performed at −8, −3, 2, 10, and 20 °C to study the decomposition rates of MH and self-preservation in presence of the two additives THF and SDS. [ABSTRACT FROM AUTHOR]

The in vitro metabolism of (-)-cis- and (-)-trans-rose oxide was investigated using human liver microsomes and recombinant cytochrome P450 (P450 or CYP) enzymes for the first time. Both isomers of rose oxide were incubated with human liver microsomes, and the formation of the respective 9-oxidized metabolite were determined using gas chromatography-mass spectrometry (GC-MS). Of 11 different recombinant human P450 enzymes used, CYP2B6 and CYP2C19 were the primary enzymes catalysing the metabolism of (-)-cis- and (-)-trans-rose oxide. CYP1A2 also efficiently oxidized (-)-cis-rose oxide at the 9-position but not (-)-trans-rose oxide. α-Naphthoflavone (a selective CYP1A2 inhibitor), thioTEPA (a CYP2B6 inhibitor) and anti-CYP2B6 antibody inhibited (-)-cis-rose oxide 9-hydroxylation catalysed by human liver microsomes. On the other hand, the metabolism of (-)-trans-rose oxide was suppressed by thioTEPA and anti-CYP2B6 at a significant level in human liver microsomes. However, omeprazole (a CYP2C19 inhibitor) had no significant effects on the metabolism of both isomers of rose oxide. Using microsomal preparations from nine different human liver samples, (-)-9-hydroxy-cis- and (-)-9-hydroxy-trans-rose oxide formations correlated with (S)-mephenytoin N-demethylase activity (CYP2B6 marker activity). These results suggest that CYP2B6 plays important roles in the metabolism of (-)-cis- and (-)-trans-rose oxide in human liver microsomes. [ABSTRACT FROM AUTHOR]

Hydrogen desorption/absorption of the LiBH/MgH mixture milled for 5 h was investigated with different initial pressures. The results showed that the initial pressure played an important role in the reversibility of the LiBH/MgH mixture. The stability of the hydrogen capacity in the subsequent desorption was improved with a higher initial pressure. A possible reason was from the increase in the formation of MgB and the lower degree in the decomposition of both LiBH to the amorphous phases of LiBH and B; and MgH to Mg, during the hydrogen desorption. However, the higher initial pressure increased the hydrogen desorption temperature. The desorption temperature was increased from 310 °C for the sample decomposing under 0.1 MPa hydrogen pressure to 360 °C for other cases. This may be due to the higher energy required to overcome the suppression of MgH and LiBH decomposition. [ABSTRACT FROM AUTHOR]

SUMMARY TiCl3 has been considered as the best catalyst for the hydrogen desorption/re-absorption of NaAlH4 in terms of kinetic enhancement. However, the formation of NaCl as a by-product leads to the decrease in the reversible hydrogen capacity of NaAlH4. In this work, TiO2 and metallic Ti were selected as catalysts for the reaction to avoid the formation of the by-product. The comparison of the catalytic activity of Ti, TiCl3, TiO2 and Ti(OBu)4 on the hydrogen desorption/absorption NaAlH4 were carried out. It was found that TiO2 doped NaAlH4 exhibits similar behavior as TiCl3 doped NaAlH4 with the reversible hydrogen capacity about 3.8 wt% (H/M). In addition, TiO2 doped NaAlH4 exhibits the superior hydrogen re-absorption rate to the one doped with TiCl3. That may be due to the Ti3+ defect sites on the surface of TiO2 would facilitate the hydrogen dissociation. Moreover, high surface area of TiO2 prevents the segregation and the morphological change of the desorbed substances (NaH and Al). This benefits to the mass transfer into the hydride system. However, doping with TiO2 also produces sodium oxide and hydroxide as by-products. Unexpectedly, metallic Ti doped NaAlH4 shows the lowest hydrogen desorption/re-absorption among the tested samples. Its hydrogen reversible capacity is around 1 wt% (H/M). The formation of TiHx (1 < x < 2) was detected in the sample after the hydrogen desorption/reabsorption. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The hydrogen desorption/absorption behaviors of LiAlH4/LiBH4 with a focus on the effects of catalysts, namely TiCl3, TiO2, VCl3, and ZrCl4, were investigated using a thermal-volumetric apparatus. The hydrogen desorption was performed from room temperature to 300 °C with a heating rate of 2 °C min-1. The LiAlH4-LiBH4 mixture with a molar ratio of 2:1 decomposed between 100 and 220 °C, and the hydrogen desorption capacity reached up to 6.6 wt %. Doping 1 mol % of a catalyst to the mixture resulted in the two-step decomposition and a decrease in the hydrogen desorption temperature. All the doped samples provided lower amountz of desorbed hydrogen than that obtained from the undoped one. No hydrogen absorption was observed under 8.5 MPa of hydrogen pressure and 300 °C for 6 h. Despite the fact each of the catalysts may affect the hydrogen storage behaviors of the mixture differently, none resulted in a change in the sample reversibility [ABSTRACT FROM AUTHOR]

The three highest hydrolysis-capacity-value isolates of Bacillus subtilis (A 002, M 015, and F 018) obtained from Thai higher termites, Microcerotermes sp., under different isolation conditions (aerobic, anaerobic, and anaerobic/aerobic) were tested for cellulase activities-FPase, endoglucanase, and β-glucosidase-at 37 °C and pH 7.2 for 24 h. Their tolerance to an ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), was also investigated. The results showed that the isolate M 015 provided the highest endoglucanase activity whereas the highest FPase and β-glucosidase activities were observed for the isolate F 018. The isolate F 018 also showed the highest tolerance to [BMIM]Cl in the range of 0.1-1.0 vol.%. In contrast, the isolate A 002 exhibited growth retardation in the presence of 0.5-1.0 vol.% [BMIM]Cl. [ABSTRACT FROM AUTHOR]

Sodium aluminum hydride or sodium alanate (NaAlH4) has been considered as a potential material for hydrogen storage. Although its theoretical hydrogen storage capacity is 5.5 wt.% at 250 °C, the material still has its drawback in the regeneration issue. With the use of certain catalysts, the regeneration problem can somewhat be alleviated with added benefits in the decrease in the hydrogen decomposition temperature and the increase in the decomposition rate. This work summarizes what we have learned from the decomposition of NaAlH4 with/without catalysts and co-dopants. The decomposition was carried out using a thermovolumetric apparatus. For the tested catalysts—HfCl4, VCl3, TiO2, TiCl3, and Ti—the decomposition temperature of the hydride decreases; however, they affect the temperature in the subsequent cycles differently and TiO2 appears to have the most positive effect on the temperature. Sample segregation and the morphological change are postulated to hinder the reversibility of the hydride. To prevent the problems, co-dopants—activated carbon, graphite, and MCM-41—were loaded. Results show that the hydrogen reabsorption capacity of HfCl4- and TiO2-doped NaAlH4 added with the co-dopants increases 10–50% compared with that without a co-dopant, and graphite is the best co-dopant in terms of reabsorption capacity. In addition, the decomposition temperature in the subsequent cycles of the co-dopant doped samples decreases about 10–15 °C as compared to the sample without a co-dopant. Porosity and large surface area of the co-dopant may decrease the segregation of bulk aluminum after the desorption and improve hydrogen diffusion in/out bulk of desorbed/reabsorbed samples. [ABSTRACT FROM AUTHOR]

Coal-based granular activated carbon (GAC) is saturated with trichloroethylene (TCE) by passing air through a fix bed adsorber. In surfactant-enhanced carbon regeneration, an aqueous solution of anionic surfactant, sodium dodecyl sulfate (SDS), is passed through the bed to induce desorption of TCE. More than 95% of the sorbed TCE was removed in the desorption operation with a 0.1 M SDS solution at a superficial flow rate of 1 cm/min. The desorption rate of TCE from pores of GAC is limited by pore diffusion and not significantly affected by either the concentration of SDS in the regenerant (when well above the critical micelle concentration) or its flow rate. From the breakthrough curve of a subsequent adsorption cycle without a flushing step following the desorption, only 7% of the virgin carbon effective adsorption capacity is observed for the regenerated carbon. With a water flushing step following the regeneration step, the effective adsorption capacity is significantly improved to about 15% of that of virgin carbon. Increased temperature of the flushing water also enhances the effective adsorption capacity of the regenerated GAC. Separate batch adsorption-desorption isotherms of SDS on GAC support the enhanced desorption of SDS at elevated temperatures. The drastic reduction in the effective adsorption capacity of regenerated GAC results from the residual SDS remaining in the pores of GAC as confirmed by thermal gravimetric analysis. Both the regeneration and water flush steps are rate limited under conditionsused here. [ABSTRACT FROM AUTHOR]

Surfactant enhanced carbon regeneration (SECR) was employed to regenerate a polymeric resin saturated with trichloroethylene (TCE), using an aqueous solution of the anionic surfactant sodium dodecyl sulfate (SDS). More than 95% of the sorbed TCE was removed in the desorption operation with a 0.1 M SDS solution at a superficial flow rate of 1 cm/min. The desorption rate of TCE from pores of the resin is limited by the concentration of SDS in the regenerant and its flow rate. From the breakthrough curve of the subsequent adsorption cycle without a flushing step following the desorption, only 40% of the effective adsorption capacity of the virgin resin is observed for the regenerated resin. With a water flushing step following the surfactant regeneration step, the effective adsorption capacity is significantly improved to about 60% of that of the virgin resin. Thermal gravimetric analysis indicates that the reduction in the effective adsorption capacity of regenerated resin resulted from the residual SDS remaining in the pores of the resin. The regeneration step is equilibrium limited whereas the water flushing step is rate limited under the studied conditions. Despite the loss of subsequent cycle adsorption capacity, SECR may still be economical as an in-situ, low temperature regeneration method. [ABSTRACT FROM AUTHOR]

Dihexyl sulfosuccinate (aerosol MA or AMA) was used to prepare microemulsion solutions in a study of the froth flotation process in batch mode to remove emulsified ethylbenzene from water. Oil removal, surfactant removal, and enrichment ratio were used to evaluate the performance of froth flotation. In this study, the effects of air flow rate, oil-to-water ratio, and equilibration time were investigated. A very high air flow rate was found to create more turbulence in the froth flotation column, resulting in low oil removal. As the oil-to-water ratio decreases, the enrichment ratio increases, whereas the oil removal slightly decreases. The froth flotation column with a feed solution in which the oil and water had been allowed to equilibrate was found to yield much higher ethylbenzene removal than that with a nonequilibrium feed solution. When the feed solution was agitated for 40 minutes to induce a state closer to equilibrium than with no mixing, the ethylbenzene removal was nearly as high as that with the equilibrium feed solution. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the relationship of the froth flotation performance in removal of emulsified ethylbenzene in water with microemulsion formation and with foam formation characteristics. The surfactant used was dihexyl sulfosuccinate (Aerosol MA or AMA) which can form microemulsions with ethylbenzene. The systems studied were designed to form Winsor Type III microemulsions with ethylbenzene, which generally correspond to ultra-low interfacial tensions between oil and water phases. By varying the surfactant concentration, NaCl concentration, and oil-to-water ratio, it was found that the lowest interfacial tension was obtained at 1 wt% AMA and 3 wt% NaCl, while the interfacial tension was not substantially influenced by the oil-to-water ratio. The highest oil removal was achieved in froth flotation with 0.3 wt% AMA and 3 wt% NaCl. No separation was experienced when the NaCl concentration exceeded 4 wt% due to the poor foamability of the froth formed under these conditions. Therefore, these results demonstrate that both interfacial tension and foam characteristics influence the efficiency of oil removal in the froth flotation process. [ABSTRACT FROM AUTHOR]

Abstract: Although hydrogen has a great potential as clean energy, safe practical storage of hydrogen for applications such as fuel cells has been a major challenge. NaAlH4 is one of the metal hydrides, which are candidates for hydrogen storage in vehicles. However, the rather slow absorption/desorption kinetics is still a significant drawback. To alleviate this problem, purified NaAlH4 was ground with TiCl3, ZrCl4, or HfCl4. Desorption kinetics and capacities were observed under TPD-like operation. Absorption efficiency was determined by raising the temperature up to 125°C. Of the three doped metals investigated for the positive effect on facilitating NaAlH4 decomposition, TiCl3 assists the best on the first reaction while ZrCl4 and HfCl4 do for the second one. Despite the kinetics enhancement directly involves with the ZrCl4 amount, there is a threshold of ZrCl4-content which affects. 6% ZrCl4 is considered as an appropriate amount to improve the hydrogen release because it simultaneously decreases the desorption temperature and gives the outstanding rate. In hydrogen desorption, ZrCl4 provides the most amount of released hydrogen, but for hydrogen absorption TiCl3-doped NaAlH4 possesses the highest capacity. It is believed that the metal size is one of the key factors resulting in such the behavior. [Copyright &y& Elsevier]

Phenol hydroxylation with TS-1 was studied in a chromatographic reactor. TS-1 not only acts as the catalyst for the reaction but also the adsorbent for the separation. The reaction/separation was carried out at 60°C with water and 0.2 wt% of aqueous H2O2 as the desorbent. Separation of hydroquinone(HQ) can be achieved in all cases. With water as the desorbent, separation of catechol(CT) depends on the phenol feed concentration, which has been confirmed from both reaction/separation in the chromatographic reactor and equilibrium competitive adsorption experiment. Some unknown by-products not commonly reported in batch experiments have been observed here. TS-1 can also be regenerated using just water. With the aqueous mixture of H2O2 as the desorbent, separation of HQ and CT is possible. Reactive separation schemes based on the simulated counter-current technology have been proposed according to the experimental results. [ABSTRACT FROM AUTHOR]

Two widely investigated methane hydrate promoters, tetra-n-butyl ammonium bromide (TBAB) and cyclopentane (CP), for methane hydrate formation and dissociation were comparatively investigated in the quiescent reactor at 2.5 °C and 8 MPa. The results indicated that the increase in the mass fraction TBAB decreased the induction time. However, it did not significantly affect the methane uptake. In the presence of CP, the increase in the CP concentration resulted in an increase in the induction time due to the increasing thicknesses of the CP layer in the unstirred reactor. Moreover, the methane uptake was varied proportionally with the CP concentration. The addition of TBAB resulted in a higher methane uptake than that of CP, since the presence of TBAB provided the cavities in the hydrate structure to accommodate the methane gas during the hydrate formation better than that of CP. On the contrary, the presence of CP significantly increased the induction time. Although the methane recovery remained relatively the same regardless of TBAB and CP concentrations, the recovery was higher in the presence of TBAB. [ABSTRACT FROM AUTHOR]

Photochemical cathodic protection (PEC) efficiency was enhanced by doping TiO2 with Cu (Cu/TiO2) through impregnation and reduction under hydrogen. The Cu loading was vaired from 0.1 to 1.0 mol% (0.1 Cu/TiO2, 0.5 Cu/TiO2, 1 Cu/TiO2). Then, up to 50 wt% Cu/TiO2 was mixed with TiO2 to form nanocomposite films. The film photocurrent and photopotential were measured under 1 mW/cm2 UV irradiation. The Cu/TiO2 film with 10 wt% of 0.5 Cu/TiO2 exhibited the highest photocurrent of 29.0 mA/g, which was three times higher than the TiO2 film. The underlying reason for the high photocurrent was the lower photopotential of film than the corrosion potential of copper for PEC. This film was also applied on copper terminal lug for anti-corrosion measurement by Tafel polarization in 3.5 wt% NaCl solution. The results showed that the photopotential of terminal lug coated with the film was −0.252 V vs. Ag/AgCl, which was lower than the corrosion potential of copper (−0.222 V vs. Ag/AgCl). Furthermore, the film can protect the corrosion of copper in the dark with 86.7% lower corrosion current (icorr) than that of bare copper. [ABSTRACT FROM AUTHOR]