Advances in mixed-matrix membranes for biorefining of biogas from anaerobic digestion.

This article provides a comprehensive review of the state-of-the-art technology of polymeric mixed-matrix membranes for CO/CH separation that can be applied in medium, small, and domestic biogas systems operating at low pressures (0.2-6 kPa). Critical data from the latest publications of CO/CH separation membranes were analyzed, considering the ratio of CO/CH permeabilities, the CO selectivity, the operating pressures at which the membranes were tested, the chemistry of the polymers studied and their gas separation mechanisms.