The rates of absorption of pure oxygen in alkaline aqueous solutions containing sodium salt of 1,4-naphthoquinone 2-sulfonic acid (NQS) as a catalyzer for the Takahax desulfurization process were measured at 25°C using a liquid jet column.
The kinetics of the absorption was examined based on the theory for gas absorption accompanied by an irreversible second order chemical reaction. The pH of the solution, that is, the concentration of hydroxyl ion plays an important role in a reaction of first order with respect to oxygen and to NQS. The reaction rate constant is directly proportional to pH in the range 9.8-11.5, for more alkaline solutions being found to be 4.5 × l06L/mole ? s. 相似文献
The removal behavior of toxic Pb2+ ions from aqueous and nonaqueous solutions by two synthetic hydroxyapatites (S-1 and S-2) has been investigated by using both batch and column methods.
It was found that Pb2+ ions in the both solutions were easily removed to the apatite samples mainly by cation-exchange reactions between the Pb2+ ions in the solutions and Ca2+ ions of the samples at room temperature. Further, in the system of aqueous PbF2 solutions, anion-exchange reactions between F? ions in the solutions and OH ? ions of the samples occurred simultaneously and the liberated OH ? and Ca2+ ions influenced removal behavior of Pb2+ and F? ions. The maximum removal amount of Pb2+ ions from the aqueous solutions was 400?mg per g of S-1. Pb? ions in the waste water from lead plating factories were completely removed to the apatite samples. In this manner, it was found that the apatites, especially S-1 can be employed as a new removal agent for the treatment of poisonous Pb2+ ions in waste water. 相似文献
ABSTRACT In the extraction of zinc(II) from hydrochloric acid solutions by trioctylmethylammonium chloride in various organic diluents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, m -xylene, nitrobenzene, carbon tetrachloride and 2,2-dichloroethane, the heat change associated with zinc(II) extraction has been examined by calorimetry. In the case of benzene used as diluent, it is confirmed that the heat change detected can be interpretated as the summation over the change in enthalpies for the relevant steps to the extraction of zi(II), taking the change in enthalpy obtained from the temperature-dependence of the distribution coefficient into account. Applying this approach of zinc(II) extraction for other diluents, it is found that the distribution of zinc (II) between aqueous and organic phases can be explained very well by assuming a regular solution. 相似文献
ABSTRACT The extraction of uranium(VI) from hydrochloric acid solutions by trioctylmethylammonium chloride (TOMAC) has been examined using various diluents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, m-xylene, nitrobenzene, carbon tetrachloride, chloroform and 1,2-dichloroethane. It was found that by assuming a regular solution, the distribution coefficient and the enthalpy change associated with the metal extraction can be expressed in terms of the solubility parameter of TOMAC, diluent and the complex formed in the organic phase and their molar volumes. Additionally an empirical relation holds between distribution coefficient and the viscosity of diluent. Further results for the extraction of divalent manganese, cobalt, copper, zinc and cadmium from hydrochloric acid solutions by TOMAC are investigated in comparison with those of uranium(VI). 相似文献
The emulsifying properties of bovine blood globin were compared with those of bovine serum albumin, hemoglobin and ovalbumin. Although the emulsifying activity of globin was greater than that of hemoglobin and ovalbumin, it decreased in the isoelectric zone owing to the low solubility of globin. Acetylation increased the emulsifying activity of globin in the isoelectric zone, but decreased in the acidic pH region. Pepsin digestion did not increase the emulsifying activity of globin, but addition of CMC to pepsin-digested globin improved both its emulsifying activity and the emulsion stability. 相似文献
Microscopic observation showed that a group of small air cells entrained during the early stage of mixing is the original cause of cell structure of bread. At the beginning of fermentation, about 3 × 108/m2 gas cells with diameters between 3 × 10−6 and 8 × 10−4 m were entrained in the dough. The distribution curve of cell size was approximately normal on a logarithmic scale. During fermentation and proofing, a great portion of carbon dioxide was released into cells larger than about 10−4 m in diameter that was equivalent to a few percentages of total number of gas cells. After baking, gas cells smaller than 10−4 m in diameter were not observed and the total number of cells in baked bread reduced to about 106/m2 with diameters between 10−4 and about 5 × 10−3 m. The critical cell size to expand generally agreed with the calculated value using an equation, rc'= 3s/E (re': critical radius to expand, s: surface tension, E: elasticity), and cited value of s and E. 相似文献
Background: Human heart changes its energetic substrates from lactate and glucose to fatty acids during the neonatal period. Noticing the lack of fatty acids in media for the culture of cardiomyocytes derived from human pluripotent stem cells (hiPS-CM), researchers have supplemented mixtures of fatty acids to hiPS-CM and reported the enhancement in the maturation of hiPS-CM. In our previous studies, we separately supplemented two polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA) or arachidonic acid (AA), to rat fetal cardiomyocytes and found that the supplementations upregulated the expressions of mRNAs for cardiomyocyte differentiation, fatty acid metabolism, and cellular adhesion. The enhancement in cellular contractility was attributed to the improvement in intercellular connection rather than a direct enhancement of the contractile force. Methods: This study reports the successive results of the effects of DHA or AA supplementation on hiPS-CM. In addition to the contractile force and mRNA measurements used in the previous study, we further investigated the effect of different cellular aggregations on the contractile force output by means of finite element analysis, measured glucose and fatty acids metabolites, and assessed cTNT and MLC2v expressions through immunofluorecsence evaluation. Results: It showed that the sole supplementation of albumin-conjugated DHA or AA can be taken up by hiPS-CM without other uptake-enhancing factors, and the supplementations may activate the CD36_ERRγ metabolic pathway. DHA or AA supplementation increased the cellular contractile ratio on collagen gels and AA supplementation stimulated hiPS-CM aggregation to form cellular clusters. The enhancement effect on the hiPS-CM contractile force was modest since the increase in contractile force was not significant. AA supplementation was more effective than DHA supplementation because it significantly upregulated mRNA expressions of P300 and CD36. However, finite element analysis showed that the formation of clusters on a collagen gel attenuated the contractile force exerted by the gel on its surroundings. Conclusion: DHA and AA, as having been supplemented in infant formulas, have no direct and significant enhancement effect on the performance of the hiPS-CM when they were supplemented individually, although they were able to enter the cellular metabolic system. The AA supplementation showed some auxiliary effect on the maturation of hiPS-CM, which is worthy of further investigation under the consideration of membrane composition alteration and remodeling of membrane molecules. 相似文献