3D-macrocycles impregnated polybenzimidazole hollow fiber membranes with excellent organic solvent resistance for industrial solvent recovery

A new strategy to synthesize integrally skinned polybenzimidazole (PBI) hollow fiber membranes for organic solvent nanofiltration (OSN) has been developed in this study by means of covalent modification with alpha,alpha'-dibromo-p-xylene (DBX) and then ionic impregnation with 4-sulfocalix [8]arene (SCA8). This double modification strategy endows the PBI hollow fiber membranes with synergistically enhanced chemical stability, mechanical strength and molecular sieving property. The modified PBI hollow fibers have a molecular weight cut-off (MWCO) of 217 Da and a narrow pore size distribution. In addition, the newly developed PBI hollow fiber membranes display a broad-spectrum of applications in various polar, nonpolar, and aprotic polar organic solvents. 1-inch PBI hollow fiber membrane modules are also fabricated to concentrate 10 wt% oil/acetone mixtures under 10 bar for 30 days, which provide an acetone permeance of around 0.35 L m(-2) h(-1) bar(-1) and an oil rejection >99.5% after stabilization. This work may propose a feasible scheme to design OSN hollow fiber membranes and fabricate industrial-size modules with sharp molecular sieving capability to realize angstromscale separations in organic solvents.

Automated summary

A new strategy has been developed to synthesize integrally skinned polybenzimidazole (PBI) hollow fiber membranes for organic solvent nanofiltration (OSN). The double modification endows the PBI hollow fiber membranes with enhanced chemical stability, mechanical strength, and molecular sieving properties. The modified PBI hollow fiber membranes have a molecular weight cut-off (MWCO) of 217 Da and exhibit a broad-spectrum of applications in various organic solvents.