Radiotracer technique has been used for the investigation of adsorption of chromium (VI) traces on bismuth trioxide from aqueous solution. The effect of pH (2–10), concentration of chromate solution (10–6–10–2M) and temperature (303–323 K) has been thoroughly investigated. The influence of certain foreign ions has also been studied. The calculated kinetic and thermodynamic parameters indicate the first order rate law, spontaneity and exothermic nature of the adsorption process. Further, IR studies have established the chemical interaction between the sorbate and sorbent and a possible mechanism of the sorption process based on ligand exchange has been proposed.
The carrier technique has been used to concentrate Cr(VI) radiometrically by studying the carrying efficiency as a function of pH of aqueous medium, added ions, carrying capacity, amount of carrier and subsequent desorption of the activity adsorbed under optimum experimental conditions. The study shows that under optimum experimental conditions, 0.15 g of ZrO2 and 0.25 g of TiO2 carry 0.01 mg and 0.001 mg of chromium respectively. Further, the activity carried under the specified conditions can be recovered more or less quantitatively by leaching the carrier.
Sorption of chromium radionuclide has been studied in the pH range of 1–10 on titanium dioxide from aqueous solutions. The adsorption isotherm obtained is of the Freundlich type. The kinetic study of adsorption and desorption of tagged chromate ions at different temperatures show that the adsorption process is exothermic innnature. Further, the feasibility of adsorption process is confirmed by calculating the thermodynamic parameters.
The kinetics of adsorption of chromate ions has been investigated radiometrically over a wide range of concentration of chromate ions (10–6–10–2M) and temperature (303–323 K). The kinetics of the process follows essentially a first order rate law with respect to adsorptive concentration and obeys the Freundlich adsorption isotherm in the concentration range studied. In addition, the kinetics of desorption of the preadsorbed species also follows a first order rate law and the activation energy for desorption is greater than that of the adsorption process. On the basis of an adsorption kinetic study, the thermodynamic parameters have been calculated. Infrared spectroscopy has shown the chemical interaction of chromate ions on the surface of MnO2.