Molecular dynamics simulations of coalescence in TBP/n-dodecane and water

Tri-n-butylphosphate (TBP) is regarded as the work horse of nuclear fuel cycle. The PUREX process involving the extraction of U (VI) and Pu (IV) from the dissolver solution using a solution of 1.1 M TBP in n-dodecane (n-DD). The physiochemical changes such as dispersion, coalescence and phase disengagement occurring at the interphase during the extraction of metal ion is a complex process. Understanding the phase disengagement at molecular level is essential for understanding the hydrodynamics of solvent extraction process. In this context, MD simulations of coalescence and phase disengagement of the organic phase (TBP or 1.1 M TBP/n-DD) and aqueous phase using AMBER-II (Assisted Model Building with Energy Refinement) are carried out. GAFF Amber force field was used for all energy minimization calculations. The corresponding potential energy is given by equation 1, and the significances of various terms are described elsewhere. All the simulations were carried out by applying suitable periodic boundary conditions with constant pressure coupling. The simulations were performed for 100 ns