Amine-functionalized cellulose/UiO-66 composite membrane for facilitated CO2 transport

In this work, Amine-functionalized CNF/UiO-66 (CNF–NH2/UiO-66) composite membranes were fabricated by incorporating UiO-66 nanoparticles in the CNF–NH2 matrix. The CO2-facilitated transfer channels can be constructed in the CNF–NH2/UiO-66 composite membrane. As a natural polymer material, CNF–NH2 would absorb water and form a gel-like structure under humidification. The adsorbed water can convert CO2 into bicarbonate ions (HCO3−) through the catalysis of amino groups on CNF–NH2. Moreover, in CNF–NH2/UiO-66 composite membranes, HCO3− could quickly migrate to the permeate side promoted by the porous UiO-66, facilitating CO2 transport. The optimum membrane gave a CO2 permeability of 257.0 Barrer with a CO2/CH4 ideal selectivity of 71.3. [Display omitted] •Hydrogel material CNF–NH2 was selected as membrane matrix for gas separation.•Adsorbed water molecules can act as fast moving carriers of CO2.•Porous UiO-66 was incorporated in CNF–NH2 matrix as a highway for CO2 transport.•Significantly higher CO2 permeability was observed for membranes in a humid state.