The inorganic membrane MCM-41 (Mobile Compound Material) is introduced as a purification method for biogas. In this experiment, the tertiary ammonium surfactant, cethyltrimethylammonium bromide (CTAB) as an organic template, tetraethylortosilicate (TEOS) as a source of silica, hydrochloric acid (HCl) as a catalyst, deionized water (H2O), and ethanol (C2H5OH) were used to create the MCM-41 membrane. X-ray diffraction (XRD), scanning electron microscopy (SEM), gas permeability, physisorption, pore size distribution, and BET (Brunauer-Emmett-Teller) surface area were used to describe the produced membrane. This membrane has excellent thermal stability, a small pore size distribution, pores that are on average around 2 nm in size, a large specific surface area of 1200 m 2 /g, and pores that are 1.08 cm 3 /g in volume. The gas separation mechanism in membrane showed the Knudsen flow, indicating the existence of mesoporous structure. This membrane is recommended for biogas plant in separation of CH4 and CO2.