Mesoporous silica thin films incorporated chitosan mixed matrix nanofiltration membranes for textile wastewater treatment

The demand of nanofiltration (NF) membranes for practical and cost-effective environmental treatment is exploding. Mixed matrix membranes (MMMs) have attracted tremendous interest on account of combining the benefits of polymer and inorganic fillers. In this study, mesoporous silica thin films with perpendicular nanochannels (SBA-15(perpendicular to)) incorporated in chitosan (CS) were fabricated for dye wastewater purification. Functional groups, such as amino or epoxy groups were introduced into SBA-15(perpendicular to) (SBA-15(perpendicular to)-NH2, SBA-15(perpendicular to)-Epo) for forming covalent bonds with chitosan matrix to improve their compatibility. The excellent performance in dye/salt fractionation in aqueous solution was demonstrated by SBA-15(perpendicular to)-Epo/CS MMMs, which realized a cut off of 585 g/mol, 99.9% rejection of Congo red, while maintaining 85% permeation of NaCl. In addition, the separation mechanism of the resulting membrane was explored. The efficient NF performance of SBA-15(perpendicular to)-Epo/CS membrane was attributed to its better compatibility between SBA-15(perpendicular to)-Epo and chitosan matrix by virtue of the formation of covalent bonds thus to ensure the high dye rejection, and the vertically oriented nanochannels arrangement facilitated the molecule transportation. This work will inspire feasible synthesis of a new generation of MMMs membranes for dye wastewater purification.

Automated summary

The study successfully fabricated mixed matrix membranes for dye wastewater purification by incorporating mesoporous silica thin films with perpendicular nanochannels into chitosan. Introducing different functional groups and forming covalent bonds improved the compatibility and performance of the membrane.