Modelling the ion-exchange equilibrium in nanoporous materials

• Дата: 2012
• Автори: Lukšič, M., Vlachy, V., Hribar-Lee, B.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики конденсованих систем НАН України 2012
• Назва видання: Condensed Matter Physics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/120288
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Modelling the ion-exchange equilibrium in nanoporous materials / M. Lukšič, V. Vlachy, B. Hribar-Lee // Condensed Matter Physics. — 2012. — Т. 15, № 2. — С. 23802:1-12. — Бібліогр.: 46 назв. — англ.

Distribution of a two component electrolyte mixture between the model adsorbent and a bulk aqueous electrolyte solution was studied using the replica Ornstein-Zernike theory and the grand canonical Monte Carlo method. The electrolyte components were modelled to mimic the HCl/NaCl and HCl/CaCl₂ mixtures, respectively. The matrix, invaded by the primitive model electrolyte mixture, was formed from monovalent negatively charged spherical obstacles. The solution was treated as a continuous dielectric with the properties of pure water. Comparison of the pair distribution functions (obtained by the two methods) between the various ionic species indicated a good agreement between the replica Ornstein-Zernike results and machine calculations. Among thermodynamic properties, the mean activity coefficient of the invaded electrolyte components was calculated. Simple model for the ion-exchange resin was proposed. The selectivity calculations yielded qualitative agreement with the following experimental observations: (i) selectivity increases with the increasing capacity of the adsorbent (matrix concentration), (ii) the adsorbent is more selective for the ion having higher charge density if its fraction in mixture is smaller.