Poly(amidoamine) dendrimer/poly(vinyl alcohol) hybrid membranes for CO2 capture

Poly(amidoamine) (PAMAM) dendrimers were incorporated into a cross-linked poly(vinyl alcohol) (PVA) matrix to improve CO2 separation performance at elevated pressures. An organic metal compound was selected as a cross-linker of PVA. The resulting self-standing PAMAM/ cross-linked PVA membrane containing 41.6 wt% of PAMAM dendrimer had both good pressure tolerance and CO2 permeance. The CO2/H2 selectivity was almost constant when the CO2 partial pressure in feed gas was from 80 to 560 kPa at 40 °C. CO2/H2 selectivity and CO2 permeance of the membrane were 32 and 1.6×10−12 m3(STP)/(m2 s Pa), respectively, at 560 kPa CO2 partial pressure in the feed gas. Both CO2 permeance and CO2/H2 selectivity increased as the operation temperature of the membrane was increased from 25 to 60 °C. A membrane containing 63.3 wt% of the dendrimer showed CO2/H2 selectivity and CO2 permeance of 42 and 1.2×10−11 m3(STP)/(m2 s Pa), respectively, at 560 kPa of CO2 partial pressure and 60 °C. The PAMAM/ cross-linked PVA hybrid membranes are durable under high pressure operation and thus show promise for applications requiring the separation of CO2 from H2 under pressurized conditions, such as in the integrated coal gasification combined cycle (IGCC) processes.