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Vapor-phase Transport (vapor-phase + transport)
Selected AbstractsSelf-Assembly of Phthalocyanine Nanotubes by Vapor-Phase TransportCHEMPHYSCHEM, Issue 8 2008Esther Barrena Dr. Gold-borne: Phthalocyanine (F16CuPc) assembles into multiwalled nanotubes by vapor deposition onto SiO2 surfaces functionalized by Au nanodots. Their length can be tuned over a large range. The picture shows the wall spacing d* of a F16CuPc nanotube as deduced from the first diffraction fringe of the electron diffractogram. [source] Estimating Persistent Mass Flux of Volatile Contaminants from the Vadose Zone to Ground WaterGROUND WATER MONITORING & REMEDIATION, Issue 2 2009M.J. Truex Contaminants may persist for long time periods within low permeability portions of the vadose zone where they cannot be effectively treated and are a potential continuing source of contamination to ground water. Setting appropriate vadose zone remediation goals typically requires evaluating these persistent sources in terms of their impact on meeting ground water remediation goals. Estimating the impact on ground water can be challenging at sites with low aqueous recharge rates where vapor-phase movement is the dominant transport process in the vadose zone. Existing one-dimensional approaches for simulating transport of volatile contaminants in the vadose zone are considered and compared to a new flux-continuity-based assessment of vapor-phase contaminant movement from the vadose zone to the ground water. The flux-continuity-based assessment demonstrates that the ability of the ground water to move contaminant away from the water table controls the vapor-phase mass flux from the vadose zone across the water table. Limitations of these approaches are then discussed with respect to the required assumptions and the need to incorporate three-dimensional processes when evaluating vapor-phase transport from the vadose zone to the ground water. The carbon tetrachloride plume at the U.S. Department of Energy Hanford Site is used as the example site where persistent vadose zone contamination needs to be considered in the context of ground water remediation. [source] Synthesis of Core/Shell Colloidal Magnetic Zeolite Microspheres for the Immobilization of TrypsinADVANCED MATERIALS, Issue 13 2009Yonghui Deng Magnetic zeolite microspheres are synthesized by combining sol-gel synthesis and vapor-phase transport. The microspheres, which have magnetite cores and crystalline zeolite shells (see figure), exhibit super-paramagnetism and a high adsorption capacity for trypsin. Trypsin-adsorbed microspheres digest proteins very efficiently (in only 15,s) in the presence of microwave radiation. [source] Cleaner process for synthesis of zeolite MCM-22 by vapor-phase transport methodASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Xingsheng Liu Abstract A cleaner process for synthesis of zeolite MCM-22 by vapor-phase transport method was studied in this paper. Firstly, zeolite MCM-22 was synthesized at different hexamethyleneimine (HMI) dosages by vapor-phase transport (VPT) method. It was concluded that the aluminosilicate gel was not crystallized completely and the product crystallinity was low when the HMI/gel mass ratio was <0.3. Then, the as-synthesized product and the surplus liquid, which were obtained at mass ratio 0.3 HMI : 1.0 gel, were characterized by TG-DTA and FTIR, respectively. It was found that a part of HMI did not play the role of structure-directing and remained in the surplus liquid after synthesis of zeolite MCM-22. The surplus liquid chemical properties, which have not change after synthesis of zeolite MCM-22 by VPT method, still contained only HMI and H2O. Re-adding of HMI and deionized water, the surplus liquid was reused to synthesize zeolite MCM-22 by VPT method. Based on the experimental results of surplus liquid reuse, it was known that the surplus liquid can be reused via re-adding of HMI and deionized water. It could make the VPT method become a cleaner process. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||