Papers by Author: Lj.S. Čerović

Abstract: The sorption of ferric and ferrous ions from aqueous solutions on the silica powder, obtained from colloidal dispersion of silica (silica sol), was studied as a function of their concentrations and solution pH. The amount of sorbed ferric and ferrous ions increases with increasing final pH of the solution. The sorption isotherms are of high-affinity type. A sorption mechanism of ferric and ferrous ions from aqueous solutions on silica is proposed.

Abstract: It has been shown recently that small organic molecules, used as dispersants in the colloidal processing of ceramic powders to adjust the forces between the particles, are quite efficient in preparing aqueous suspensions of high solid loadings and low viscosity. One of them is 4,5-dihydroxy-1,3-benzenedisulfonic acid, disodium salt monohydrate, ((OH)2C6H2(SO3Na)2·H2O), commercially known as Tiron. The adsorption of Tiron, as a function of its concentration and solution pH, onto alumina was investigated by the solution depletion method, applying UV spectrophotometry. KNO3 (10-2 mol/l) was used as the background electrolyte. The obtained results indicate an increase in the amount of adsorbed Tiron with its increasing concentration. The maximum adsorption was recorded at pH≈7 when the Tiron molecule was uncharged, i.e. undissociated (pKa1=7.6). The experimental data were fitted with different adsorption isotherm models. The maximum amount of Tiron adsorbed, as well as the constants of adsorption process were calculated.