The assessment of materials for crossflow nanofiltration of organic/organic liquids and the development of scale-up options

With the aqueous applications of crossflow filtration being well established, comparable developments in the field of organic/organic liquid systems remain in their infancy. Progress within the field has been hindered by the fact that there are few systems which are both robust to hydrocarbon solvents and provide good fluxes/separations under realistic operating conditions. The authors of the current paper have explored a number of materials for crossflow filtration of organic media and found that the dense organic polymer PDMS (polydimethyl siloxane) affords the best results (see Figure 1). Building on initial results, a full assessment of the membrane performance has been undertaken. Using a laboratory set-up, a range of pure and mixed hydrocarbon streams have been passed across the PDMS to assess performance with time and under variable operating conditions. Recent papers and presentations by the afore mentioned authors have considered transport mechanisms across a 2 μm PDMS membrane supported on PAN. Results from flat sheet experiments have been used to design a larger scale unit. The operation of this system has shown excellent read across in terms of flux and selectivity. It is hoped that the work detailed within this presentation will prompt other workers in the field to consider the development of novel organic polymers to build on the applicability of filtration for organic/organic separations.