Sub-micro porous thin polymer membranes for discriminating H2 and CO2.

Polymeric membranes with high permeance and remarkable selectivity for simultaneous H2 purification and CO2 capture under industry-relevant conditions are absent. Herein, sub-micro pores with precise molecular sieving capability are created in ultra-thin (13-30 nm) polymer membranes via controllable transformation of amine-linked polymer (ALP) films into benzimidazole-and-amine-linked polymer (BIALP) layers. The BIALP membranes exhibit stable unprecedented H2/CO2 selectivity of 120 with a H2 permeance of 315 GPU. Furthermore, high pressure (up to 11 bar) and thermal (up to 300 °C) resistance is delivered. This work provides a concept on designing porous polymeric membranes for precise molecular discrimination.

Effects of Operating Parameters on Ionic Liquid Membrane to Remove Humidity in a Green Continuous Process.

Membrane processes are promising methods to separate gases from feed streams without phase changing. A hybrid process, the combination of ionic liquids with a ceramic membrane (ILM), has been developed for humidity removal in a green continuous process. This new concept provides a more efficient and available ionic liquid (IL)-based membrane regeneration process, which just switches the moist feed stream to dry air. Furthermore, the ILM presents high stability and mechanical resistance during long-time operation. In addition, the influences of several operating parameters, including flow rate, temperature, absolute pressure, and feed concentration on process efficiency were investigated. The lower inlet flow rate was found to be favorable for drying humid air. Moreover, when the pressure increased, the mass of absorbed water was increased, while the feed concentration had no significant effects on the membrane separation performance. However, the operating temperature had a great effect on humidity removal. It is necessary to note that the processes at room temperature can limit the energy consumption. The absorbing process of ILM remained efficient after several absorption desorption cycles. Therefore, the new ILM hybrid process that has been developed has great potential for consecutive humidity removal processes.