Asian Research Thesis Index

Abstract

Dispersion-free membrane-based Liquid-Liquid Extraction (LLE) is an emerging technique to recover a variety of solutes from aqueous streams. The process employs a Hollow Fiber Membrane Contactor (HFMC) that accomplishes the mass transfer between feed and solvent without any dispersion. Compactness of the unit, known and higher interfacial area, less solvent loss and independent control of operating flowrates are benefits of the process that make it attractive for researchers. Fluid dynamics and mass transport modeling of HFMC for dispersion free LLE process has been given the most attention in recent years. In the current study, numerical model has been developed to explore the dispersion free LLE processes. Extraction of copper (II) and aroma compounds from aqueous streams was taken as case study for the validation of the model.Copper (II) was extracted with trifluoro-acetylacetone (TFA) in commercially available HFMCs’ modules from LiquiCelTM (USA). A 2D model was developed for convection-diffusion mass and momentum transfer using continuity and Navier-Stokes equations. The model was simulated with Computational Fluid Dynamics (CFD) technique to study copper (II) extraction. The MatlabTM and COMSOL MultuphysicsTMsoftwares were used as simulation tools. The codes developed in MatlabTM were coupled with COMSOL MultiphysicsTM for recycled based dynamic system. Model was validated with experimental data and simulation was run to check effects of hydrodynamics conditions on contactor performance. Simulations were performed under various operating parameters and membrane geometrical characteristics in order to determine solute extraction efficiency, distribution profiles of copper (II) concentration, flux and velocity in 2-D. CFD model was then extended to investigate the extraction of four aroma compounds. These compounds have been recovered from aqueous solutions with hexane as an organic solvent in HFMC. Another model, which is based on resistance-in-series approach was also applied to study the extraction of copper (II). After validation with experimental results from the literature, the model was run to investigate the distribution of copper (II) at interface, transmembrane flux and height of transfer unit (HTU). The study revealed that an integrated mathematical model and numerical simulations can be effectively applied for the optimum design of membrane-based extraction processes.

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