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

Abstract

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(⊥)) incorporated in chitosan (CS) were fabricated for dye wastewater purification. Functional groups, such as amino or epoxy groups were introduced into SBA-15(⊥) (SBA-15(⊥)-NH 2 , SBA-15(⊥)-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(⊥)-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(⊥)-Epo/CS membrane was attributed to its better compatibility between SBA-15(⊥)-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.

Boosting brackish water treatment via integration of mesoporous γ-Al2O3NPs with thin-film nanofiltration membranes

“…They reported a higher rejection rate from the bare nanofiltration membrane (up to 64% for CaCl 2 and 95% for Na 2 SO 4 ), increased flux permeability to 20.11 kg/(m 2 .h), and higher rejection values for various dyes (up to 90%). Lai and co-workers also fabricated chitosan-based mesoporous silica thin films with superior nano-filtration membranes for the purification of dye wastewater 16 . They stated that the rejection of Congo Red dye was more than 98% with the superior performance of the used membrane.…”