60 KB453 KB56 KB199820252006Lukšič, MihaPizio, OrestVlachy, Vojko14 straništevilka:3letnik:53str. 292-305ISSN:1318-0207COBISSID:27965189URN:URN:NBN:SI:doc-6AID3Y3SenSlovensko kemijsko društvoActa chimica slovenicaadsorpcijaelektrolitifizikalna kemijaionimetoda Monte CarlomodeliMonte Carlo methodračunalniške simulacijeraztopinetermodinamikaModelling electrolyte adsorption in nanoporous materials|The structural and thermodynamic properties of a model electrolyte solution confined in disordered matrices with charged obstacles were studied by means of the grand canonical Monte Carlo simulation. A disordered nanoporous medium was modelled as i) an equilibrium distribution of ions in a +1:-1 primitive model electrolyte; ii) a system of dipolar hard spheresč iii) a collection of chain like molecules with alternating charge on the beads (polyampholyte): and iv) as a system of charged chainlike molecules (oligoelectrolyte) with the pertaining counterions. The confined electrolyte was assumed to be in thermodynamic equilibrium with the obstacles forming the nanoporous matrix andan external electrolyte of the same chemical composition. The solvent in all these cases was treated as a dielectric continuum. In the present study we were interested in effects of the distribu-tion of charged obstacles on the mean activity coefficient of the confined electrolyte. The computer simulations were performed for a set of values of the model parameters such as the concentration of matrix ions and of the annealed electrolyte, pre-quenching conditions and the conditions of observation. The results confirmed our previous findings that the properties of an annealed electrolytedepend strongly on the conditions of observation (temperature and dielectric constant of solvent), as well as on the concentrations of all components. The effect of the matrix-charge distribution, investigated in this work, was found to be significant and more important for higher Coulomb couplingsS pomočjo velekanonične Monte Carlo simulacije smo proučevali strukturne in termodinamske lastnosti raztopin modelnega elektrolita v neurejeni porozni snovi, ki vsebuje elektronevtralno kombinacijo nabojev. Porozno snov (adsorbent) smo si zamislili kot i) ravnotežno razporeditev ionov v +1: -1 elektrolitu pri neki koncentraciji c0, ii) kot sistem dipolov (delec sestavljata pozitivno in negativno nabiti kroglici), iii) kot zbir verig, sestavljenih iz togih kroglic z alternirajočim nabojem (poliamfolit), ter iv) kot sistem pozitivno nabitih verigastih molekul (oligoelektrolit) s pripadajočimi protiioni. Modelni elektrolit (adsorbat) je bil v termodinamskemravnotezju z adsorbentom (delci adsorbenta so bili zamrznjeni v prostoru) ter zunanjo raztopino enake kemijske sestave. Topilo smo v vseh primerih obravnavali kot dielektrični kontinuum. Zanimalo nas je, kakšen vpliv ima razporeditev nabojev v porozni snovi na srednji koeficient aktivnosti adsorbiranega modelnega +1:-1 elektrolita. Izvedli smo računalniško simulacijo za niz parametrov, ki doloeajo stanje modela; spreminjali smo koncentracijo in razporeditev nabojev nanoporozne snovi ter koncentracijo modelnega elektrolita, pogoje priprave adsorbenta ter pogoje pri katerih sistem opazujemo. Računi so potrdili nasa pretekla dognanja, da termodinamične lastnosti adsorbata močno zavisijo od temperature in dielektrične konstante topila, kakor tudi od koncentracije delcev adsorbenta ter adsorbata. Vpliv razporeditve nabojev adsorbenta na adsorpcijo elektrolita je pomemben, in še zlasti izrazit pri močnejših Coulombskih interakcijahTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaSlovensko kemijsko društvo