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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.

The porous mixed oxide SiO 2 /TiO 2 /Sb 2 O 5 obtained by the sol-gel processing method presenteda 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 ionexchange equilibria of Li + and K + were quantitatively described with the help of the model of fixedtetradentate centers. The results of simulation evidence that for the H + / Li + exchange the usual situationtakes place: the affinity of the material to the Li + ions is decreased with increasing the degree of ionexchange. On the contrary, for K + the effects of positive cooperativity, that facilitate the H + / K + exchange,were revealed.