The examination of the extraction of lanthanum in the aqueous solutions with trioctylamine fixed on the support material

In this study, the separation of lanthanım (III) from aqueous solutions was investigated by extraction chromatography technique. Extraction chromatography is a special type of liquid-liquid chromatography and it is advantageous being a simple method useful in the removal of lanthanides and actinides. In this technique, stationary phase is formed by coating the organic solution upon the available support material. In our study, a tertiary amine TOA which has shown a selectivity to actinides and lanthanides was coated on the diatome earth as a support material. Diatome earth have been selected on account of its light, high porosity, chemical stability, hardy,absorbency. In the first part of the work, the adsorption behaviours of lanthanum (III) onto diatome earth were investigated. The adsorption isotherms were obtained from the equilibrium data and hence this proses was found multilayer. Freundlich, D-R, BET, Langmuir and Temkin adsorption constant and the adsorption energy were calculated. The adsorption data were fitted Freundlich (KF= 0.0084 L/g, n= 1.448) and BET (Q= 26.87x10-7 mol/g, B= 96.15) isotherms. The adsorption experiments were verified at varying temperature and the results showed that the adsorption decrease as a solution temperature increase. Adsorption enthalpy (7H), entropy (7S) were calculated respect to 7H0= -4.378 kJ/mol, 7S0= 18.1 J/molK, and free energy (7G0) values was found negative. In the second part of the work, the extraction of lanthanum on the stationary phase which coated tri-n-octyl amine was investigated by batch technique. The parameters effecting the efficiency of lanthanum extraction; pH of the solution, initial lanthanum concentration, TNOA concentration, H2SO4 concentration, shaking time, shaking speed and temperature were studied and optimum conditions were determined. Under the optimum conditions maximum lanthanum extraction was %79.69±2.07. In addition, extraction of lanthanum with diatome earth which coated TNOA was investigated in presence of some other ions. For this purpose, suitable synthetic solutions were prepared and this processes were applied sample solutions. Key Words: Adsorption, Diatome earth, Extraction Chromatography, Lanthanum, Tri-n-octyl amine