چكيده به لاتين
Microfluidic systems have small fluid dimensions (microns) that provide a high surface-to-volume ratio for rapid mass and heat transfer. Due to smaller volume, faster processes, lower costs, portability, efficiency and high safety; Microfluidic systems as a process intensification tool have microchemical applications, microbiology, medicine and .... Solvent metal extraction (SX) is a potential process in which two immiscible phases (aqueous and organic) come into contact. For rapid extraction of metal (base metals, precious metals, radioisotopes, etc.) from the aquatic environment, a high surface-to-volume ratio is required, which can be achieved in a microfluidic system. Despite the mentioned advantages, low volumetric throughput has been the reason for less use of this system in industry. In addition to the parallelization method, Kriel et al. Have designed a new multi-stream system containing 49 parallel streams with very high volumetric throughput compared to previous systems. Has been paid. To investigate the transfer of platinum from aqueous to organic phase (type secondary amine), two single-phase and two-phase simulation models were investigated. In the single-phase simulation mode, the moving walls were considered as an interface with a constant equilibrium mass fraction. To simulate two-phase hydrodynamics, the periodic boundary condition and the VOF multiphase model were used to track the interface between the two immiscible organic and aqueous phases. To reduce the computational time, the problem was solved steady state. The species transport model was selected to investigate the mass fraction distribution of soluble species for both simulation modes. The mass transfer mechanism was made possible by using the first Fick’s law penetration by software coding by applying the source term for the phase fraction equations and species transport. The simulation results were validated for both cases with a maximum relative error of 12% compared to the experimental results. Numerical results show that with increasing contact time (0.4 to 1.2 sec) in a certain phase ratio (2.2), due to more interface contact; The extraction efficiency (with 5% error) improved by up to 80% and at a constant contact time (maximum 3 sec), with increasing phase ratio (0.5 to 2.2) due to increased chemical potential (solubility) of the receptor phase for the solute species; extraction efficiency is on the rise and it has maximum of 95.3%. The total volumetric mass transfer coefficient in a certain phase ratio is inversely related to the contact time and in contrast in a certain contact time, is directly related to the phase ratio value.
