The performance of composite supported polymeric liquid membranes in the Membrane Aromatic Recovery System (MARS)

This study investigates the possibility of using a composite-supported polymeric liquid membrane (CSPLM) configuration for the Membrane Aromatic Recovery System (MARS). The membrane was prepared by impregnating the liquid membrane phase into the pores of a composite flat sheet membrane consisting of a microporous support and a thin non-porous layer. A polyvinylidenfluoride (PVDF) microporous support coated with a thin non-porous polydimethylsiloxane (PDMS) layer was chosen as a composite membrane due to its superior combination of mass transfer rates and chemical resistance among the membranes tested and polypropylene glycol (PPG) was used as a liquid membrane phase due to its high affinity for phenol. The resulting membrane showed uniform selectivity and operational stability under the continuous MARS operating conditions for more than two months. The mass transfer rates (7.7×10-7ms-1) were 5 times higher than those of the silicone rubber tubing (1.5×10-7ms-1) which is used in commercial scale MARS technology. The CSPLM also exhibited reduced water flux and low sodium ion transfer. The partition coefficient of phenol between PPG/water was measured as 84. A marked effect of ionic strength on partition coefficient of phenol was observed with partition coefficient increase to 134 when measured in the presence of 20 wt% KCl in phenol aqueous solution.