Removal of dissolved tri-n-butyl phosphate from aqueous nitric acid solutions: kinetic studies

The present work deals with the kinetic study for the removal of dissolved TBP from aqueous nitric acid solutions using Normal Paraffin Hydrocarbon (NPH) as the solvent. Effect of different parameters like type of solvent, concentration of organic phase, concentration of aqueous phase, organic to aqueous phase (O/A) ratio and temperature on the extraction of TBP, has been successfully optimized. Around 62% of dissolved TBP was extracted from aqueous feed solution containing 0.3M HNO3 with 3% TBP in NPH as the solvent and O/A ratio of 1:1 in only 5 min at 35°C. The graphical representation of the kinetic expressions for different parameters predicted that the extraction of TBP follows the first-order behaviour. The rate constants values obtained from the first-order equation have also verified the optimized parameters. This study will provide an aid in development of a robust and effective process for removal of dissolved TBP with minimum waste generation.