Sorption Studies of Divalent Metal Ions on ZnO

Abstract

The sorption of Zn2+, Ni2+, and Co2+ on ZnO was studied as a function of pH, temperature, and concentration of the metal cations. The extent of sorption was found to increase with the increase in pH and concentration and decrease with the increase in temperature. The potentiometric titrations data showed that the sorption mechanism of the transition metal cations changed from adsorption to precipitation with the increase in pH. The sorption and precipitation of the metal cations were explained with the help of a new equation derived from the law of mass action. FTIR studies revealed the formation of a double hydroxide of Zn and metal ions concerned on the surface of the solid. The dissolution studies of the ZnO were also employed to evaluate the sorption mechanism of the metal cations on the ZnO. The decrease in the extent of adsorption of the metal cations with temperature was due to an increase in dissolution of the ZnO.

Kinetic and thermodynamic study of Cd(II), Co(II) and Zn(II) adsorption from aqueous solution by NiO

“…1 reveals that NiO has ball shape with a porous structure. The point of zero charge (PZC) of NiO is observed to be 8.45 at 303 ± 1 K, which is similar to the one reported for ZnO [22]. The isoelectric point (IEP) of NiO was also determined at 303 K using the Zeta potentiometer model CAD Nikon Eclipse 50i.…”

Temperature effect on xanthate sorption by chalcopyrite

“…2-4. These figures show that xanthate ion sorption increase with increases in temperature at all the pH values in the range 8-10, which may be due to an increase in the solubility of xanthate ion with a rise in temperature and activation of certain inactive sites on the surface of the ore [28]. Further, these figures show that the temperature effect is more significant when the initial concentration of xanthate in solution is high.…”

Surface charge properties of Fe2O3 in aqueous and alcoholic mixed solvents

“…Metal oxides/hydrous oxides are naturally occurring discrete minerals or in the form of coatings on other particles and exist in various amorphous and crystalline forms [1][2][3][4][5]. In aqueous suspensions they develop surface electrical charges from the dissociation of the surface hydroxyl groups and complexation of the background electrolyte ions.…”