The Li+, Na+ and K+ ion exchange reaction process on the surface of mixed oxide SiO2/TiO2/Sb2O5 surface prepared by the sol-gel processing method

Abstract

The porous mixed oxide SiO2/TiO2/Sb2O5 obtained by the sol-gel processing method presented a good ion exchange property and a high exchange capacity towards the Li+, Na+ and K+ ions. In the H+/M+ ion exchange process, the H+ / Na+ could be described as presenting an ideal character. The ion exchange equilibria of Li+ and K+ were quantitatively described with the help of the model of fixed tetradentate centers. The results of simulation evidence that for the H+ / Li+ exchange the usual situation takes place: the affinity of the material to the Li+ ions is decreased with increasing the degree of ion exchange. On the contrary, for K+ the effects of positive cooperativity, that facilitate the H+ / K+ exchange, were revealed.

Simulation of adsorption equilibria on hybrid materials: Binding of metal chlorides with 3-n-propylpyridinium silsesquioxane chloride ion exchanger

“…In general, for new kinds of hybrid materials, origins of nonideality and cooperativity are not clear enough. Thus, in contrast to the material studied in the present work, silica and cellulose/Al 2 O 3 carriers modified with pyridinium groups do not demonstrate nonideality effects when metal chlorides are adsorbed [18,23,24]. Many factors may affect the chemisorption process and the state of bound ligands and complexes, for instance, heterogeneous surface topography, porous structure of materials, peculiar conformation and accessibility of fixed reacting groups, electrostatic effects, solvation/desolvation effects, and so on.…”

“…, S. Each set θ vs included t Q corresponding to the vth model and the log β (Z) i values. The latter were uniformly distributed within ellipsoids with borders defined by condition (18). The membership functions for components of θ vs were assigned as…”

“…They were used, in particular, to get keener insight into sorption and ion exchange equilibria on surfaces of such hybrids as cellulose acetate fibers (CAF) coated with Al 2 O 3 and modified with nitrogen-containing ligands [17], sol-gel derived SiO 2 /TiO 2 /Sb 2 O 5 mixed oxide [18], CAF coated with highly dispersed aluminum [19,20] and zirconium [21] phosphates, silica gel coated with 3-n-propyl(4-methylpyridinium) silsesquioxane chloride polymer [22,23], CAF coated with n-propyl-1,4-diazabicyclo(2.2.2)octane chloride [24], SiO 2 /Nb 2 O 5 prepared by the sol-gel method and modified with phosphoric acid [25], xerogels containing aniline [26] and xylenol orange groups [27], and others. This paper discusses the simulation of sorption equilibria of metal chlorides on the surface of 3-n-propylpyridinium silsesquioxane chloride polymer from ethanol media.…”