The Functionalization of PES/SAPO-34 Mixed Matrix Membrane with [emim][Tf 2 N] Ionic Liquid to Improve CO 2 /N 2 Separation Properties.

The use of ionic liquid [emim][Tf₂N] as an additive in polyethersulphone (PES) and nano-sized silico-aluminophosphate-34 (SAPO-34) mixed matrix membrane was studied through the incorporation of different amounts of [emim][Tf₂N] in the membrane composition, as presented in this work, varying from 10 to 40 wt%. Through gas permeation tests using CO₂ and N₂, the membrane composition containing 20 wt% [emim][Tf₂N] led to the highest increase in CO₂ permeability and CO₂/N₂ selectivity. The use of low concentrations of additive (10–20 wt%) promoted a state called antiplasticization; in this state, the permeability was even more regulated by the kinetic diameter of the species which, in this work, permitted achieving a higher CO₂/N₂ selectivity while increasing the CO₂ permeability until an optimal condition. [emim][Tf₂N] also promoted a better dispersion of SAPO-34 particles and an increase in the flexibility of the polymeric matrix when compared to a film with the same composition without [emim][Tf₂N]. Moreover, the characterizations corroborated that the inclusion of [emim][Tf₂N] increased the zeolite dispersion and improved the polymer/zeolite compatibility and membrane flexibility, characterized by a decrease in glass transition temperature, which helped in the fabrication process while presenting a similar thermal resistance and hydrophilicity as neat PES membrane, without affecting the membrane structure, as indicated by FTIR and a contact angle analysis. [ABSTRACT FROM AUTHOR]