Electrodeposited NiMoP catalysts on carbon felt for hydrogenation of indigo during electrocatalytically splitting water

Electrochemical hydrogenation is an environmentally favorable alternative to chemical reduction of indigo because it performs under ambient conditions using water as the donor of hydrogen. The purpose of this work is to fabricate electrocatalysts with high activity and durability for electrocatalytic hydrogenation of indigo. This work compares the performances of a series of Ni based catalysts (Ni, NiMo, NiP and NiMoP) on the substrate of carbon felt (CF) for electrolyzing water. Both the overpotential and Tafel slop are decreased as a function of the components as Ni > NiMo > NiP > NiMoP. Hence, NiMoP/CF shows the excellent performance based on the thermodynamics (η₁₀ = 239 mV) and kinetics (Tafel slope = 89.7 mV·dec^?1) for splitting water. Further, the electrode of NiMoP/CF was used for the electrocatalytic hydrogenation of indigo. The conversion efficiency and Faradic efficiency can be improved as 26.2% and 10.7% respectively. Furthermore, the dyeing behavior of the electrohydrogenated indigo is similar to that of conventional reduction methods. Thus, the present work offers foundational results and paves the way for the design of new catalytic materials for the reduction of vat dyes.     

Synthesis of manganese titanate and its precursors from xerogel

An overview of research on the synthesis of manganese titanates is presented. The xerogel of Mn–Ti–O–C–H composition was synthesized from manganese acetate and titanium tetrabutylate via liquid-phase method using organic solvents. The calcination of xerogel in air at 450 °C and 700 °C yielded manganese titanate precursors in the form of a nanostructured mixture of Mn₂O₃ and TiO₂. Annealing at 1000 °C, manganese metatitanate MnTiO₃ was obtained. Reference experiments with initial reagents included, separately, thermal decomposition of Mn(CH₃COO)₂×4H₂O and the product of Ti(OC₄H₉)₄ hydrolysis. The composition, structure, and properties of the products were studied using X-ray diffraction, scanning electron microscopy, elemental analysis, diffuse reflectance IR Fourier spectroscopy, thermogravimetry, and by measuring specific surface area. The data presented by these different techniques are basically consistent with each other (with an increase in the annealing temperature, an increase in globule size and decrease in specific surface area are observed; structuring occurs within the long- and short-range order; the size of the crystallites does not exceed that of the globules; elemental composition correlates with phase composition; the endothermic character of the reaction of MnTiO₃ formation at 900 °C is confirmed by a thermodynamic calculation). Nevertheless, some unexpected effects were revealed (based on the FTIR diffuse reflection spectra, mixed oxide Mn–Ti–O is formed in the surface layer of particles already at 450 °C and 700 °C; etc.). Application of the proposed technique for modifying Al₂O₃ powders, with the aim of implementing low-temperature sintering of corundum ceramics, is discussed.     

Manganese ferrite-polyaniline hybrid materials: Electrical and magnetic properties

Magnetic MnFe₂O₄ nanopowders were synthesized by an original solvothermal method in the absence and in the presence of tetra-n-butylammonium bromide (TBAB) and Tween 80 (TW) as surfactants. Manganese ferrite/polyaniline (PANI) hybrid materials were synthesized by in situ polymerization of aniline on the surface of MnFe₂O₄ using ammonium persulfate as oxidant. The purpose of the study was to investigate the influence of the two surfactants on the properties of the MnFe₂O₄ powders and of their composites with PANI. The specific surface area, the cumulative surface area of pores and the cumulative volume of pores are influenced by the nature of surfactant in case of MnFe₂O₄ powders and are higher by comparison to those of the MnFe₂O₄/PANI hybrid materials. The values of saturation magnetization in case of MnFe₂O₄ powders are higher than those of the hybrid materials and are not influenced by the surfactant nature. These features revealed that MnFe₂O₄ powders can be efficiently used as adsorbents for the purification of wastewaters. The values of the electrical conductivity of the composites exhibit a significant increase in comparison to the MnFe₂O₄ powders and depend on the surfactant nature. The highest value of electrical conductivity was achieved by the composite obtained using Tween 80 as surfactant (σ_DC = 54.5·10^?5S?m^?1) which was close to that of PANI (σ_DC = 61.2·10^?5 S?m^?1). The fact that the magnetic and electric properties of the synthesized MnFe₂O₄/PANI composites can be changed by design, demonstrate the high potential of these materials to be used in magneto-electric applications.     

GSM无线公话产品中的干扰研究

GSM90 0 /1 80 0固定无线公用电话桌面型话机在开发过程中遇到严重的噪音问题 ,一度成为开发工作的瓶颈。本文就这一噪音问题进行了分析与测试 ,并针对干扰源采取相应的措施 ,在产品开发中付诸应用 ,最终解决了 GSM桌面型无线公话的噪音问题     

气调库及气调库设备

分析果蔬贮藏保鲜期的生理变化，介绍气调保鲜库设计施工验收中的技术要求，保鲜工艺和主要设备。     

开关磁阻电机调速系统在煤矿井下的应用

随着开关磁阻电机的调速控制系统日臻完善，因其优越性能使得在各行业得到迅速推广，但在煤矿井下的特定环境中使用该调速系统仍存在着诸多问题有待分析研究。     

Kinetic of CO2 absorption and carbamate formation in aqueous solutions of diethanolamine

The absorption rates of CO₂ into aqueous solutions of Diethanolamine (DEA) with varying concentrations from 0.2 to 4M and temperature range from 293 to 323 K were measured by using a laboratory stirred reactor. The CO₂ partial pressure was varied in a range that the reaction would occur in pseudo first order regime. Experimental data were analyzed and the kinetic parameters associated with the reaction were determined. The activation energy for the deprotonation of the intermediate zwitterion was estimated at about 11.4 kcal/mol. The contribution of carbamate formation to the overall absorbed CO₂ was experimentally evaluated and found to be of the order of 100%.     

The treatment of waste-air containing mixed solvent using a biofilter 2. Treatment of waste-air containing ethanol and toluene in a biofilter

An experiment for five stages of a biofilter-run was performed to investigate the effect of hydrophilic ethanol and hydrophobic toluene on the biodegradation of hydrophobic toluene and hydrophilic ethanol, respectively, when waste-air containing toluene and ethanol was treated by a biofilter. Removal efficiencies of toluene and ethanol began to decrease when inlet load surpassed 90 g/m³/h and 100 g/m³/h consistent with maximum elimination capacities of toluene and ethanol, respectively. At the end of the biofilter-run, removal efficiencies for toluene and ethanol were decreased and maintained at 65% and 40%, respectively. The concentration of toluene at 1st sampling port was raised by factor of two in the 3rd stage of the biofilter run when the inlet load of ethanol co-feed was increased by 1.5 times, while the process conditions of toluene were maintained the same as those of the 2nd stage of biofilter-run. According to the result of Mohseni and Allen, it may be interpreted that removal efficiency of hydrophobic toluene was affected by the presence of hydrophilic ethanol when high load of hydrophobic toluene was applied like that of the 1st sampling port of the biofilter. However it was not the case when a low load of hydrophobic toluene was applied like those of the 2nd, 3rd and 4th sampling ports since hydrophobicity of toluene is much less that of α-pinene. Thus, it may be suggested that biodegradation of hydrophobic VOC was interfered by hydrophilic VOC dissolved in the biolayer and the degree of interference was proportional to the inlet load of hydrophobic VOC as well as that of hydrophilic VOC and was inversely proportional to the solubility of hydrophobic VOC. However, it was inferred that the existence of hydrophobic toluene from waste-air can hardly inversely hinder the removal of hydrophilic ethanol in the biofilter when timeevolutions of hydrophilic ethanol concentrations of this experiment were compared with those of the previous experiment of biofilter to treat waste-air containing ethanol only.     

Photochemical reduction of molecular weight and number of double bonds in natural rubber film

Natural rubber (NR) can be degraded depending on various factors such as heat, mechanical force, chemical reaction, and light. Light is a very interesting factor because it can cause the NR to degrade under low temperature and pressure. The photo-degradation of NR films was carried out to investigate the effects of the light and the temperature on the reduction of the weight-average molecular weight (Mw) and the double bonds in the NR films. The NR films, with and without catalysts, titanium dioxide (TiO₂), and potassium persulfate (K₂S₂O₈), were exposed to light from a mercury light bulb at 7,000 and 36,000 lux, and at the temperature of 25 °C and 80 °C for 192 hrs. After exposure, the Mw of the NR films was analyzed by gel permeation chromatography (GPC). Changes in the Mw were used to construct a kinetic model for the process, (1/Mw)=(1/Mw₀)+(kt/2M₀) where k is the rate constant, and M₀ is the Mw of the monomer unit. The linear relationship between 1/Mw and time suggested pseudo first-order processes with random scission. The Mw distribution information from the GPC was used to calculate the number of double bonds in the NR films. The trend of the double bonds reduction curves was quite similar to the result obtained from the calculation from the FTIR spectra. This indicated that this calculation method might possibly be another alternative way to obtain the number of double bonds in the NR.