Papers by Keyword: Preparation

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Authors: X.Q. Chen, Y.Y. Liu, K.H. Qi, X. Zhou, J.H. Xin
Abstract: Monodisperse silica particles containing available active C=C bonds were directly prepared by a simple two-step sol-gel method. In the first step the hydrolysis of vinyltrimethoxysilane (VTMS) was performed under acidic conditions in an aqueous solution. In the second step the condensation of the siloxane precursors progressed under basic conditions, resulting in production of silica nanoparticles containing available active C=C bonds. The products were characterized using SEM and FTIR.
Authors: Jun Zhang, Hua Bo Li, Yong Hua Duan
Abstract: Aluminum dross is the staple solid waste in electrolytic aluminum industry. Taking full advantage of the aluminum dross is of great significance for controlling environmental pollution and saving resource. In this work, brown fused alumina is successfully prepared using aluminum dross as raw material through different pretreatments for aluminum dross. The results show that the brown fused alumina product is comprised of α-Al2O3 (ca.95%), NaCl (ca.1~3%) and CaF2 (ca.1~3%), and contents of the other components are as follows: MgO 0.33%, SiO2 1.12%, Fe2O3 0.41%, CaO 0.58%, TiO2 0.13%, K2O 0.05%, Na2O 0.87% and V2O5 0.92%. This quality of the resulting brown fused alumina can fully meet the national standards of China (GB/T 2478-2008).
Authors: Yong Tian Wang
Abstract: In this paper we describe the synthesis of nanocrystalline boron nitride (BN) with a hollow morphology by the reaction of NH4BF4 and NaNH2 at 500 oC for 24h. Characterized by XRD, FTIR, XPS, TEM, and EDXA spectra, the composition and morphology of the products were confirmed. The possible formation mechanism was also discussed.
Authors: Shun Dong Miao, Wen Jian Weng, Kui Cheng, Chen Lu Song, Pi Yi Du, Gao Ling Zhao, Ge Shen, Jian Xun Wang, Gao Rong Han
Abstract: Nano-sized zinc containing β-tricalcium phosphate (ZnTCP) powders were synthesized by a co-precipitation method. The co-precipitation took place in an ice-water bathed beaker, after further washing, freezing, lyophilizing and calcining at 800°C, the precipitates transformed to ZnTCP powders. The XRD pattern of the ZnTCP powders demonstrated a pure β-TCP phase. TEM observation revealed the particle size is about 100-120nm, which is favorable for TCP particles to form composites, such as polymer based composite, and as well to attain a desired microstructure. It was found zinc incorporation could eventually result in the decrease of particle size, thus be beneficial for its further application.
Authors: Xi Shi Tai
Abstract: Novel schiff-base ligand and its Mg (II) complex were prepared by one-pot method after mixing salicylaldehyde, 4, 4’-Diaminodiphenylamine and MgCl2•6H2O. The luminescent properties of the Mg (II) complex material were investigated experimentally in solid state and in organic solvents. The results show that the Mg (II) complex material emits strong green fluorescence at 532 nm when excited at 393 nm even if the spit widths of excitation and emission are 2.5 nm, which may be applied as a potential fluorescent material in a wide range of new technologies.
Authors: Xu Li, Guan Zhong Lu, Yang Long Guo, Yun Guo, Yan Qin Wang
Abstract: A novel solid superbase catalyst of La2O3-ZnO/ZrO2 was prepared, and its H– value (Hammett function) of surface basic strength reaches 26.5. The catalytic activity of La2O3-ZnO/ZrO2 was evaluated for the transesterification of soybean oil (SBO) with methanol to biodiesel in a fixed bed reactor under atmospheric pressure. The results show that the chemical composition of the La2O3-ZnO/ZrO2 catalyst influences both its H– value and catalytic performance, the appropriate content of ZrO2 is 60 wt.% and the La2O3/ZnO molar ratio is 4~5/1. La2O3-ZnO/ZrO2 is an effective catalyst for the transesterification of SBO, and the SBO conversion reaches 71.3% at 70°C for 12h.
Authors: Yu Liang An, Qing Yi Hou, Xia Yuan, Gang Zhang
Abstract: A novel and practical route for preparing carbon coating metal nanomaterials using polyvinyl alcohol as the starting materials was presented. Carbon coating iron nanoparticles can be effectively synthesized by carbonizing polyvinyl alcohol using Fe as catalyst in hydrogen flow. The carbohydrate was carbonized in a controllable way that leads to a large amount of carbon coating iron nanoparticles. Transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and thermogravimetric analysis (TG) were employed to characterizing nanomaterials. The growth mechanism of carbon coating iron nanoparticles is briefly discussed in term of composition and structure of precursor.
Authors: Mao Lin Zhang, Long Feng Li
Abstract: A nanometer coupled oxide ZnO-SnO2 was prepared by the fractional homogeneous co-precipitation route using urea as the latent precipitant under boiling reflux condition. The samples prepared from different initial concentrations of urea or at different calcination temperatures were characterized by X-ray diffration (XRD) or transmission electron microscopy (TEM). It was found that the coupled oxides ZnO-SnO2 mainly consist of nanosized ZnO and SnO2, the calcination temperature had obvious effect on the phase composition and the crystal size of the samples obtained, and the precipitant concentration also had obvious effect on the oxide particles size and the production rate of ZnO. Moreover, their photocatalytic activity was investigated for the liquids-phase photocatalytic degradation of methyl orange (MO) in water under UV light irradiation.The coupled oxides showed better photocatalytic activity for the degradation of MO than the pure ZnO or SnO2.
Authors: Zheng Zhai, Qing Liu, Xing You Xu, Ju Yuan Li, Zheng Li, Xiang Chen Li
Abstract: A new type of isotope preparation system was designed with excellent accuracy, high degree automation and high security. In view of the existing equipment with automation low degree automation, poor safety, much long preparation time and low precision of the sample preparation problems, a series of improvements were introduced, such as the automatic sampling device, contact valve, vacuum auxiliary system, gas meter and digital dashboards. It was found that the instrument finely designed had the characteristics such as high accuracy, automation and security. Combined with the sample detection device, the preparated sample had excellent detection results. Meanwhile, a set of standard operating procedures had also been formed. Furthermore, the sample preparation process was briefly discussed.
Authors: He Ping Tan, Huai Ping Li, Hang Song, Wen Ping Xu, Chi Guan, Li Ping Ran
Abstract: A simple, clean and economical way of separation and preparation noncaffeine tea polyphenols from green tea waste in one-step by Sephadex LH-20 column chromatography was developed. 20% (v/v) ethanol solution was used for removing caffeine and other components in the first stepwise elution, and tea polyphenols was eluted with 60% (v/v) ethanol solution by using reversed flow in the second stepwise elution. The yield of tea polyphenols above 11% with the purity about 98% and the content of catechins more than 91%, and the content of caffeine in tea polyphenols have not been detected by high-performance liquid chromatography. The recovery of tea polyphenols by column chromatography were about 86%, and the stability of preparative way is very good. Compared with conventional extraction and decaffeination ways, this way has more excellent advantages, such as cheaper raw material, no toxic residues, higher yield, commercially feasible and environment friendly.
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