Recyclable nanocomposites for carbon dioxide fixation and membrane separation using waste polycarbonate

•Robust PU/SiO2 nanohybrids with a tensile strength of 35.5 MPa and over 700 % elongation at break.•Nanohybrids prepared from polymer waste conversion process with an approximately 98% functional group selectivity.•Nanohybrids exhibiting particle sizes ranging from 100 to 500 nm.•PU/SiO2 membrane involving CO2 reuse with a PCO2 of 24.02 barrer, and a selectivity of 32.85 (αCO2/N2).•Gas separation membranes for CO2 capture and storage from post-consumption materials.