Kinetic study for adsorption of chromium tri-Oxide CrO3 on kaolinite surface

الملخص EN

The removal of 3CrO by using kaolinite has been investigated, as a function of initial concentration, pH and temperatures.

Adsorption process was attained to equilibrium within 60 minutes which indicated by uv-visible absorption spectroscopy technique at wave length 390 nm.

The best results which are used in this study were achieved at pH of 4, and 290 K, in this range of pH and temperature, the chromium tri oxide transformation hydro-chromate into bi-chromate takes place.

The equilibrium data for adsorption are fitted to the Freundlich, Langmuir and Dubinin Radushkevich (D-R) isotherm equations.

Values of parameters for theses isotherms equations were calculated.

The mean energy of adsorption Eads, was also calculated from the adsorption energy constant King, its value determined from the D-R isotherm equation.

The temperature thermodynamic parameters like ΔG, ΔH and ΔS have been calculated.

Values of enthalpy ΔH showed that the adsorption process is exothermic.