Abstract
The paper presents methods of preparation and applications of hydrophobic platinum catalysts in nuclear field and environmental protection. These catalysts allow the transport of gaseous reactants and reaction products to and from catalytic active centers since the pore blocking by water is avoided. Hence the activity and stability of the catalysts increase and isotopic exchange columns with simpler internal structure can be achieved. The aim of the paper is: 1. to give a data base regarding the preparation methods of the optimal catalyst type; 2. to indicate the utilization and operation procedures of hydrophobic catalysts with mixed and simple packings; 3. to evaluate the performances and applications of hydrophobic catalysts. Over one hundred of hydrophobic catalysts of the active metal/support type were prepared in our laboratory. Hydrophobic features were obtained by different methods like these: - coating a hydrophilic conventional catalyst with a hydrophobic agent such as silicone or teflon; - supporting the active metal directly into the pores of a hydrophobic support; - mixing the teflon powder with a hydrophilic conventional catalyst; coating the support with teflon followed by the impregnation with the precursor of the active metal. The most important application of these catalysts is detritiation of the
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Ionita, Gheorghe;
Popescu, Irina;
Stefanescu, Ioan;
Varlam, Carmen
[1]
- National Institute of Research-Development for Cryogenics and Isotopic Technologies, ICSI, PO Box 10, Str. Uzinei nr. 4, OP4, RO-240050 Rm. Valcea (Romania)
Citation Formats
Ionita, Gheorghe, Popescu, Irina, Stefanescu, Ioan, and Varlam, Carmen.
Hydrophobic catalyst applications in the nuclear field and in environmental studies; Evaluarea aplicatiilor catalizatori hidrofobi in domeniu nuclear si al mediului inconjurator.
Romania: N. p.,
2002.
Web.
Ionita, Gheorghe, Popescu, Irina, Stefanescu, Ioan, & Varlam, Carmen.
Hydrophobic catalyst applications in the nuclear field and in environmental studies; Evaluarea aplicatiilor catalizatori hidrofobi in domeniu nuclear si al mediului inconjurator.
Romania.
Ionita, Gheorghe, Popescu, Irina, Stefanescu, Ioan, and Varlam, Carmen.
2002.
"Hydrophobic catalyst applications in the nuclear field and in environmental studies; Evaluarea aplicatiilor catalizatori hidrofobi in domeniu nuclear si al mediului inconjurator."
Romania.
@misc{etde_20620580,
title = {Hydrophobic catalyst applications in the nuclear field and in environmental studies; Evaluarea aplicatiilor catalizatori hidrofobi in domeniu nuclear si al mediului inconjurator}
author = {Ionita, Gheorghe, Popescu, Irina, Stefanescu, Ioan, and Varlam, Carmen}
abstractNote = {The paper presents methods of preparation and applications of hydrophobic platinum catalysts in nuclear field and environmental protection. These catalysts allow the transport of gaseous reactants and reaction products to and from catalytic active centers since the pore blocking by water is avoided. Hence the activity and stability of the catalysts increase and isotopic exchange columns with simpler internal structure can be achieved. The aim of the paper is: 1. to give a data base regarding the preparation methods of the optimal catalyst type; 2. to indicate the utilization and operation procedures of hydrophobic catalysts with mixed and simple packings; 3. to evaluate the performances and applications of hydrophobic catalysts. Over one hundred of hydrophobic catalysts of the active metal/support type were prepared in our laboratory. Hydrophobic features were obtained by different methods like these: - coating a hydrophilic conventional catalyst with a hydrophobic agent such as silicone or teflon; - supporting the active metal directly into the pores of a hydrophobic support; - mixing the teflon powder with a hydrophilic conventional catalyst; coating the support with teflon followed by the impregnation with the precursor of the active metal. The most important application of these catalysts is detritiation of the heavy water used as moderator and coolant in CANDU type reactors. Build-up of tritium in heavy water following the neutron capture by deuterium leads to a reduction in the moderating properties and at the same time leads to a contamination hazard for both operation personnel and environment. Tritium recovery leads this way to both improving the moderating qualities of the heavy water and obtaining valuable pure tritium of high importance in fusion research and other laboratory studies. One gram of tritium costs about USD 10,000. The physical chemical process is water-hydrogen catalyzed isotopic exchange. Also discussed in the paper is the separation of tritium from liquid wastes resulting from the spent fuel reprocessing. The following conclusions are drawn: the hydrophobic catalyst using platinum and teflon offers the highest activity and stability; using the catalyst as mixed ordered packing was demonstrated as most efficient in tritium separation from heavy water; extending the use of this catalyst for reactions in liquid or vapor water appears to be also possible.}
place = {Romania}
year = {2002}
month = {Jul}
}
title = {Hydrophobic catalyst applications in the nuclear field and in environmental studies; Evaluarea aplicatiilor catalizatori hidrofobi in domeniu nuclear si al mediului inconjurator}
author = {Ionita, Gheorghe, Popescu, Irina, Stefanescu, Ioan, and Varlam, Carmen}
abstractNote = {The paper presents methods of preparation and applications of hydrophobic platinum catalysts in nuclear field and environmental protection. These catalysts allow the transport of gaseous reactants and reaction products to and from catalytic active centers since the pore blocking by water is avoided. Hence the activity and stability of the catalysts increase and isotopic exchange columns with simpler internal structure can be achieved. The aim of the paper is: 1. to give a data base regarding the preparation methods of the optimal catalyst type; 2. to indicate the utilization and operation procedures of hydrophobic catalysts with mixed and simple packings; 3. to evaluate the performances and applications of hydrophobic catalysts. Over one hundred of hydrophobic catalysts of the active metal/support type were prepared in our laboratory. Hydrophobic features were obtained by different methods like these: - coating a hydrophilic conventional catalyst with a hydrophobic agent such as silicone or teflon; - supporting the active metal directly into the pores of a hydrophobic support; - mixing the teflon powder with a hydrophilic conventional catalyst; coating the support with teflon followed by the impregnation with the precursor of the active metal. The most important application of these catalysts is detritiation of the heavy water used as moderator and coolant in CANDU type reactors. Build-up of tritium in heavy water following the neutron capture by deuterium leads to a reduction in the moderating properties and at the same time leads to a contamination hazard for both operation personnel and environment. Tritium recovery leads this way to both improving the moderating qualities of the heavy water and obtaining valuable pure tritium of high importance in fusion research and other laboratory studies. One gram of tritium costs about USD 10,000. The physical chemical process is water-hydrogen catalyzed isotopic exchange. Also discussed in the paper is the separation of tritium from liquid wastes resulting from the spent fuel reprocessing. The following conclusions are drawn: the hydrophobic catalyst using platinum and teflon offers the highest activity and stability; using the catalyst as mixed ordered packing was demonstrated as most efficient in tritium separation from heavy water; extending the use of this catalyst for reactions in liquid or vapor water appears to be also possible.}
place = {Romania}
year = {2002}
month = {Jul}
}