MMMs with tunable free volume for H2 purification at 150°C

by Neal, Tai-Shung, CHUNG
MMMs with tunable free volume for H2 purification at 150°C

Membranes with attractive H2/CO2 separation properties at 150°C and thermally controlled free volume are the pre-requisites for their industrial application in pre-combustion CO2-removal processes. We report the H2/CO2 separation properties of di/tri-amine vapor cross-linked mixed matrix membranes (MMMs) with tunable free volume at elevated temperatures up to 150 °C. Free volume of cross-linked MMMs was molecularly tuned by altering the degree of chain motion using ethylenediamine (EDA), diethylenetriamine and tris(2-aminoethyl)amine. Both CO2 adsorption isotherms and positron annihilation lifetime spectroscopy conducted at 35 °C and 150 °C elucidated the evolution of chain motion and molecularly tuned free volume in the cross-linked MMMs. A more restricted degree of chain motion was achieved in the cross-linked network and the resultant membrane has a lower H2 permeability but a higher H2/CO2 selectivity at 150 °C. Among the vapor cross-linked MMMs, the EDA-treated MMMs was distinguished for the best H2/CO2 separation performance with an H2 permeability of 141 Barrer and an H2/CO2 selectivity of 11.6 at 150 °C.

 

This work has been published in Adv. Mater. on November 30, 2016 (doi: 10.1002/adma.201603833)

Corresponding author(s): Tai-Shung, Chung (chencts@nus.edu.sg)
Corresponding authors(s) Webpage: http://membrane.chbe.nus.edu.sg/