Electrophoretic Deposition of Zeolites Focused on Attendant Electrodecantation and Subsequent Growth of Electric Current

0504558 - ÚFCH JH 2020 RIV DE eng J - Journal Article
Brabec, Libor - Plšek, Jan - Kočiřík, Milan
Electrophoretic Deposition of Zeolites Focused on Attendant Electrodecantation and Subsequent Growth of Electric Current.
ChemistrySelect. Roč. 4, č. 11 (2019), s. 3185-3190. ISSN 2365-6549. E-ISSN 2365-6549
Institutional support: RVO:61388955
Keywords : silica * electrodeposition * electrosedimentation * ion exchange * stratification * zeolite cations
OECD category: Physical chemistry
Impact factor: 1.811, year: 2019
Method of publishing: Limited access

During electrophoretic deposition (EPD) a significant amount of high-silica MFI zeolite or silica does not deposit onto the vertical anode because it undergoes fast electrodecantation e.g. in ethanol(96%). The velocity of electrodecantation is high particularly for small silica spheres which do not sediment by gravitation. The other part of dispersed particles is deposited onto the anode and forms a layer whose thickness increases along the depth of immersion. The multiple increase of electric current comes after EPD of a zeolite. Zeolite cations are expelled to the liquid phase by excess protons occurring near the anode by electrolysis of traces of water. The liquid-phase conductivity prevails over the electrical resistance of the deposited layer. In order to deposit the dispersed zeolite quantitatively, EPD cell with horizontal electrodes is employed. The fraction of Na+ cations expelled from deposited MFI zeolite reaches even 90%. The current increases much more after EPD of Al-rich zeolite *BEA containing more Na+ cations. The gradient of Na+ concentration across the cut of the zeolite layer is demonstrated.
Permanent Link: http://hdl.handle.net/11104/0296164