Papers by Keyword: Purification

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Authors: Hui Wang, Han Sheng Gong, Xiang Chen Meng, Li Li Man
Abstract: A bacteriocin produced by Lactobacillus brevis KLDS1.0373 which was isolated from “Jiaoke”, a traditional, naturally fermented cream from Inner Mongolia in China was reported in this article. The bacteriocin was partially purified by ammonium sulfate precipitation followed by sequential gel filtration chromatography, and the apparent molecular weight of the partially purified bacteriocin was estimated at approximately 3.8 kDa.
Authors: Ji Li Zha, Shao Yong Xu, Guo Qiang You, Si Yuan Long
Abstract: In the present paper, the current state of magnesium scrap recycling via melt refinement was reviewed and the difficulties confronted in the developing fluxless techniques were highlighted. Then, the working principle of a fluxless technique newly developed in China was briefly introduced followed by chemical and light microscopy investigation of the processing quality of the recycled ingots in comparison with the commercial ingot produced with predominant flux processing to have a first insight into the difference of the two refining techniques. The results indicate that a stable, continuous and cost effective melt refinement can be achieved with the commercial Mg scraps in-house fluxless recycling system.
Authors: Wen Bin Zhang, Jia Xing Zhu, Ya Song Pu, Yan Ping Su
Abstract: . Aiming at the purification of rotor center’s orbit, a new approach was presented by using ensemble empirical mode decomposition (EEMD). Ensemble empirical mode decomposition decomposed a complicated signal into a series of intrinsic mode functions (IMFs). Then according to prior knowledge of rotating machinery, chose some interested IMFs and reconstructed the needed signal. By doing this the noises would be eliminated successfully. At last the purification of rotor center’s orbit was obtained by extracting the useful signal component. Simulation and practical results show the advantage of EEMD in noise de-noising and purification of rotor center’s orbit. This method also has simple algorithm and high calculating speed; it provides a new way for purification of rotor center’s orbit of rotating machinery.
Authors: Lei Shen, Mei Liu
Abstract: A new purification procedure was used for the purification of multiwalled carbon nanotube (MWCNTs) based on nitric acid oxidation. Using thermogravimetric analysis (TGA), and Energy dispersive X-ray analysis (EDX) to characterize the morphologies of MWCNTs oxidized under various conditions. The TGA provided clear evidence for the presence of carboxylic groups (COOH) attached to the surface of MWCNTs resulting from the acid treatment.
Authors: Jian Guo Liu, Chang Zhen Chen, Jing Liu
Abstract: The objective of this work is to develop a novel dialysis process for the isolation of phosvitin from hen egg yolk avoiding the use of organic solvents and polyvalent metals. This bioseparation process consists of NaCl precipitation, heat treatment and dialysis, which was proposed on the basis of the property difference (especially solubility and thermostability) among yolk proteins. The native molecular mass of the purified phosvitin estimated by fast protein liquid chromatography on a Superdex 75 column was about 165 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed two bands around 35 kDa. The nitrogen to phosphorus atomic ratio of the purified phosvitin was 2.8 ± 0.2, with a yield of 87.1%. The phosvitin product had α-helix of 36%, β-sheet of 28% and random coil of 36% at pH 7.0, consistent with the literature values. This shows that the purified phosvitin folded with a reasonable secondary structure.
Authors: Zhen Peng, Li Zhang, Chun Sheng Wang, Ke Fu Yao
Abstract: It is well-known that TiO2 is an environmental benign photocatalyst which can be used to decompose harmful organic compounds. Recently, many studies are concentrated on the purification of industrial wastewater due to the requirement of environmental protection. In present study, TiO2 nanomaterials supported by fine zeolite particles have been used as the photocatalyst to purify the oily wastewater. It has been found that the oil concentration in the modulated water can be reduced significantly and rapidly under the action of photocatalytic degradation and the ultraviolet light radiation. After 80 minutes, oil concentration in the modulated water can be reduced by more than 80%. The results suggest that TiO2 nanomaterials supported by fine zeolite particles are effective material for purification of oily wastewater. In addition, the present results show that the efficiency of water purification can be significantly increased by use of mechanical stirring during the photocatalytic degradation process.
Authors: Fei You, Jin Sun, Bing Teng, Lin Hua Xia, Xin Xing Jiang, Hui Xu, De Gao Zhong, Romano A Rupp
Abstract: DAST (4-dimethylamino-N-methyl-4-stilbazolium tosylate) crystal material was synthesized and purified by a relatively simple method. The synthesis process was easy to operate experimentally and the cost of raw materials can be cut down. The purification process was much easier than the previously published method. Fourier transform infrared spectrum (FTIR) was used to analyze the functional group of raw material and no extra functional groups were found. Nuclear magnetic resonance (NMR) study was performed to identify the different modes presented in the compound. The results showed that the quality of the prepared crystal raw material could meet the requirements on crystal growth. DAST crystals were grown from the synthesized raw material by slowly cooling method. The crystal structure was characterized by X-ray diffraction (XRD) study and the results showed that the crystal grown from the synthesized raw material was the same as that grown from pure DAST crystal raw material.
Authors: Yan Hong Wang, He Zhao, Y.D. Huang
Abstract: In this paper, the preparation of 2, 6-diamino-3, 5-dinitropyridine (DADNP) were systematically investigated. The optimal method was found. The key parameters have been systematically studied, such as the synthesis route, temperature, solvent, time, the reactant ratio, and the purification route. The optimal route was confirmed and would have an important reference for pilot plant scale-up.
Authors: Lin Guo, Xin Yuan Liu, Vanesa Sanchez, Charles Vaslet, Agnes B. Kane, Robert H. Hurt
Abstract: Carbon nanomaterials are among the best known and most promising products of the nanotechnology movement. Some early studies suggest that fullerenes and nanotubes may pose significant health risks, and this has given rise to an emerging literature on carbon nanotoxicology. This young field has now begun to yield insight into toxicity mechanisms and the specific material features involved in those mechanisms. This paper explores the potential to alter those material features through post-processing or reformulation with the goal of reducing or eliminating carbon nanomaterial health risks. The paper emphasizes the important roles of metal content and bioavailability, carbon surface chemistry, and nanomaterial aggregation state. The nanotechnology movement has been given a unique "window of opportunity" to systematically investigate the toxicity of nanotechnology products and to develop ways to manage health risks before large scale manufacturing becomes widespread.
Authors: Yi Min Sang
Abstract: The morphology, interspace of a novel nanofiber membrane are characterized by scanning electron microscopy (SEM). The membrane, named M-1, is prepared from chloridized polyvinyl chloride by high-voltage electrospinning process. The removals of divalent metal cations including Cu2+, Pb2+ and Cd2+ from the simulated groundwater by M-1 have been investigated. From static adsorption experiments, maximum uptakes of Cu2+, Cd2+, Pb2+ and their adsorption equilibrium time have been obtained respectively in the simulated groundwater.
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