利用LIBS对AlCl3溶液定量分析

本文中利用激光诱导等离子体击穿光谱方法对AlCl3溶液进行了定量分析。在实验中以Al作为内标元素,将配置好不同的浓度的AlCl3溶液以射流方式产生等离子体,利用内标法和谱线–浓度法进行定量分析发现谱线面积–浓度法效果比内标法好,尤其是浓度低自吸收强时利用谱线面积–浓度法进行定标比较精确。

Carbon dioxide reforming of methane over bimetallic catalysts of Pt-Ru/γ-Al_2O_3 for thermochemical energy storage

The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by using the wetness impregnation method. The prepared catalysts were characterized by a series of physico-chemical characterization techniques such as BET surface area, thermo-gravimetric （TG）, transmission electron microscope （TEM） and X-ray photoelectron spectroscopy （XPS）. In addition, the amount of carbon deposits on the surface of the catalysts and the type of the carbonaceous species were discussed by TG. It was found that the bimetallic Pt-Ru/7-A1203 catalysts exhibit both superior catalytic activity and remarkable stability by comparison of monometallic catalysts. During the 500 h stability test, the bimetallic catalyst showed a good performance at 800 ~C in CO2 reforming of CH4, exhibiting an excellent anti-carbon performance with the mass loss of less than 8.5%. The results also indicate that CO2 and CH4 have quite stable conversions of 96.0 % and 94.0 %, respectively. Also, the selectivity of the catalysts is excellent with the products ratio of CO/H2 maintaining at 1.02. Furthermore, it was found in TEM images that the active carbonaceous species were formed during the catalytic reaction, and well-distributed dot-shaped metallic particles with a relatively uniform size of about 3 nm as well as amorphous carbon structures were observed. Combined with BET, TG, TEM tests, it is concluded that the selected bimetallic catalysts can work continuously in a stable state at the high temperature, which has a potential to be utilized for the closed-loop cycle of the solar thermochemical energy storage in future industry applications.

Highly Active and Stable Ni_2P/SiO_2 Catalyst for Hydrogenation of C_9 Petroleum Resin

Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reduction（TPR） method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity（LHSV） was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values（250 mg Br/100g） within 300h, showing the high activity and stability of Ni2P/SiO2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction（XRD）, BET surface area（BET） analysis, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared（FTIR） pyridine adsorption, and X-ray photoelectron spectroscopy（XPS）. Compared with the traditional sulfurated-Ni W catalysts, Ni2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni2P/SiO2 catalyst. The stability of Ni2P/SiO2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni2P nanoparticles and weak surface acidity for the Ni2P/SiO2 catalyst.

Adsorption of Cholesterol on Carbon Powders

Carbon powders have the ability to remove cholesterol from solution by adsorption. Various combinations from among 12 different types of carbon powders （including two medical carbons）, having a wide range of surface area and porosity, were used to perform cholesterol adsorption experiments. The cholesterol concentration in a cyclohexane solvent （37 ~C, shaking 200 rpm） was detected at 215 nm using ultraviolet spectroscopy. Most adsorption occurred in the first 30 to 60 minutes. A Langmuir model was used to fit the amount of cholesterol adsorbed per gram of carbon. The medical carbon, Natural Elements Activated Charcoal, adsorbed 234 mg of cholesterol adsorption per gram of carbon. The experimental percentages of cholesterol removed from solution （maximum 98%） were correlated with nitrogen Branauer-Emmett-Teller （BET） surface areas and micro, meso, and macropore volume distributions. Surface area alone was not a suitable predictor of cholesterol adsorption. However, carbon powders exhibiting a large surface area along with significant meso and macropores were shown to be effective in adsorbing cholesterol from a nonpolar environment. Ingestion of a medically approved carbon powder with a large surface area and sufficient meso and macroporosity may be able to adsorb cholesterol in the intestinal tract and thereby lower cholesterol levels in the body.

Effect of Polyethylene Glycol on the Properties of γ-Al_2O_3 Formation by Polyaluminum Chloride

A polyaluminium chloride solution with high Al 13 content self-prepared was used as material for preparing the spherical γ-Al 2 O 3 by the sol-gel and oil-drop method. Polyethylene glycol with different molecular mass was used as surfactant to investigate the effect on property of γ-Al 2 O 3 . The physical property was characterized by 27 Al NMR (nuclear magnetic resonance) spectra, X-ray diffraction, FT-IR (Fourier transform infrared spectroscopy) and TG-DTA (thermogravimetric-differential thermal analysis). The results showed that surface area, pore volume and pore size of γ-Al 2 O 3 all increased with the increase of polyethylene glycol molecular mass in the experimental research range, and polyethylene glycol 10000 was the most suitable pore forming additive. γ-Al 2 O 3 with surface area of 339 m 2 ·g 1 , pore volume of 0.59 cm 3 ·g 1 and pore diameter of 6.9 nm were obtained at 450 °C.