EXAMINING AND TUNING PERFORMANCE STABILITY OF 2D ZN-TCPP (FE) MEMBRANE IN THE NANOFILTRATION OF ORGANIC DYE SOLUTINS

Abstract

This study investigates organic solvent nanofiltration (OSN) using the membranes stacked by 2D Zn-TCPP(Fe) nanosheets. A group of organic dyes with different molecular weights, hydrophilic properties and functional groups were selected as probe solutes in ethanol, isopropanol and ethyl acetate, respectively, to examine their OSN outcomes. The intermolecular interactions of organic solvent, dye and Zn-TCPP(Fe) nanosheets profoundly influence the mass transfer in the nano channels of the lamellar membrane. Representatively, the isopropanol solution of Brilliant Blue G dye turns out to have a favorable OSN performance (> 90 % rejection with an average permenance of 175 LMHB), whereas replacement of isopropanol by ethanol results in incipient loss of rejection. But for this solution, incorporating an optimal dose of ZIF-8 nanograins into the nanosheets via co-deposition to form a particle-over-lamellae structure unveils a significant improvement on OSN.To comprehend how these factors dominating OSN, besides the experimental characterizations, both visco-molar volume and Stokes-Einstein diameter that describe dynamic properties of solute molecule in a solvent are employed to assist the analysis. Fluid dynamic sizes and solvent-solute-membrane interactions constitute dual effects mutually impacting OSN performance of the membrane.