抄録
Liquid-liquid extraction of titanium(IV) from sulfuric acid solution using 2-ethyl hexyl phosphonic acid mono 2-ethyl hexyl ester (PC-88A) in toluene has been studied. The extraction of titanium(IV) was found to be quantitative with 0.03 M PC-88A in toluene in the acidic range of 0.01–0.3 M and 12.0–14.0 M H2SO4. Titanium(IV) extracted in the organic phase was stripped with the mixture of 2.0–3.5 M H2SO4 and 3% H2O2. Effect of reagent concentration on the extraction of titanium(IV) was studied.
The stoichiometry of the extracted species of titanium(IV) was determined on the basis of slope analysis method. The extraction reaction proceeds with cation exchange mechanism in the range of 0.01 M–0.3 M H2SO4 and the extracted species is in the TiOR2·2HR form and at higher acidty (12.0 M–14.0 M H2SO4) it proceeds by solvation, the extracted species is Ti(OH)3HSO4·4HR. Temperature dependence of the extraction equilibrium constants was examined to estimate the apparent thermodynamic functions (ΔH, ΔS and ΔG) for extraction reaction.
