▎ 摘　　要

NOVELTY - Preparation of highly stable graphene oxide (GO)-ionic liquid supported liquid membrane involves (1) adding graphene oxide nanosheets into deionized water, ultrasonically dispersing to obtain 0.01-0.05 g/L graphene oxide dispersion liquid, centrifuging for 20-30 minutes at 3000-5000 rpm, and separating the supernatant liquid, (2) fixing alpha-alumina substrate in a vacuum filtration device, vacuum filtering the supernatant liquid, and obtaining two-dimensional GO wet film, and (3) vacuum degassing an ionic liquid, adding into a reaction device, fixing the GO wet film 2 cm away from the bottom cavity, placing at 100-120degrees Celsius environment, at a pressure of 0.05 MPa for 1-5 hours, and vacuum drying for 10-12 hours at 40degrees Celsius. USE - Preparation of highly stable graphene oxide-ionic liquid supported liquid membrane for separating carbon dioxide and methane (claimed) in marsh gas purification to obtain biogas. ADVANTAGE - The method enables economical preparation of thin-liquid graphene membrane having high stability, excellent gas permeability and pressure resistance using minimum ionic liquid.