Highly efficient chitosan-based bio-polymeric membranes embedded with green solvent encapsulated MIL-53(Fe) for methanol/MTBE separation by pervaporation

An emerging family of solvents known as deep eutectic solvents has been heralded as a sustainable alternative to traditional solvents. Due to the low compatibility with polymeric materials, the direct use of a deep eutectic solvent (DES) as a solvent is still in the challenging phase. Therefore, we have developed a novel strategy to add DES into the polymer matrix. We have encapsulated MIL-53(Fe) using the choline chloride and ethylene glycol DES mixture and incorporated it into the chitosan polymer matrix. This study prepares chitosan-based biodegradable and sustainable membranes by adding different nanofillers such as DES, MIL-53(Fe), and DES@MIL-53(Fe) for methanol/MTBE azeotropic mixture separation. The prepared nanofillers and bio-degradable membranes are characterized using various analytical techniques such as FESEM, HRTEM, AFM, FTIR, XRD, TGA, XPS, mechanical strength, and wettability. The best separation results are found for the DES@MIL-53(Fe)/CS membranes because the membrane exhibit the characteristic of both components together. The highest total flux and methanol selectivity are observed for the F4 membrane, which is 2329 g m(-2) h(-1) and 207.06. Based on the surface characteristics and performance study, the DES@MIL-53(Fe)/CS membrane can have better potential in wastewater treatment and other membrane-based separation processes.

Automated summary

A novel strategy of adding deep eutectic solvents (DES) into the polymer matrix was developed to overcome the low compatibility issue. Choline chloride and ethylene glycol DES mixture was used to encapsulate MIL-53(Fe) and incorporate it into the chitosan polymer matrix. The DES@MIL-53(Fe)/CS membrane showed the best separation performance, with the highest total flux and methanol selectivity.