Developing Methods for Producing Hydrophobized Platinum Catalysts of Different Types
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ISTRY AND TECHNOLOGY OF RARE, TRACE, AND RADIOACTIVE ELEMENTS
Developing Methods for Producing Hydrophobized Platinum Catalysts of Different Types A. N. Bukina, *, V. S. Moseevaa, and S. A. Marunicha aMendeleev
University of Chemical Technology of Russia, Moscow, 125047 Russia *e-mail: [email protected]
Received February 18, 2019; revised February 20, 2019; accepted March 13, 2019
Abstract—The development of a thermostable hydrophobic platinum catalyst is an important scientific and practical problem. The purpose of this work is to study methods for the hydrophobization of γ-Al2O3 granules with solutions of organic silanes. It has been shown that the thermostability of a hydrophobic coating with surface modifiers is no less than 500°C. Samples of classic and eggshell catalysts are synthesized on the basis of the supports that are obtained. Keywords: hydrophobized catalyst, eggshell catalyst, hydrogen isotope exchange DOI: 10.1134/S0040579520050085
INTRODUCTION The development of nuclear power engineering and the atomic industry is a priority for modern Russia, the success of which depends on solving a number of concrete technologic and environmental problems. In particular, one important problem for research and industrial heavy-water nuclear reactors are maintaining the quality of the heavy-water moderator by means of removing protium and tritium contaminations from them. The most promising method to normalize the isotope composition of heavy water is the chemical isotopic exchange (ChIE) of hydrogen with water. The key component of the given technology is the hydrophobic catalyst. In Russia, an RCTU-3SM hydrophobic platinized catalyst is used based on styrol-divinylbenzene (SDVB) copolymer [1]. The RCTU-3SM catalyst has rather high activity in the hydrogen isotope exchange (HIE) reaction with water and demonstrates a 20-year operation resource of the unit for the deprotiation and detritiation of heavy water at the Petersburg Nuclear Physics Institute in Gatchina [2]. Around the world, hydrophobic catalysts on Teflon are also used with carbon coating on a carbon substrate on inorganic supports modified with hydrophobizing solutions [3]. Developing such catalysts is an important goal of investigations when problems of molecular hydrogen activation are solved in systems containing liquid water.
Main Directions of Investigations The physical properties of organic supports limit their application on some steps of the ChIE process within the water–hydrogen system. 1. Utilizing Waste Hydrogen This problem is currently solved by dumping waste hydrogen into environment, and the alternative is converting hydrogen into water vapor in a low-temperature catalytic convertor (LCC) [4, 5], where the direct contact of water and reaction gases occurs. Despite the fact that the process is carried out at the temperature of water as a heat-transfer agent in the LCC of no higher than 95°C, local heating of the catalyst grain can reach hundreds of degrees. Therefore, the application of RCTU-3SM is unacceptable because of the
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