Natural gas is a homogenous liquid of low viscosity and low density or it may also be defined as a complex mixture of combustible hydrocarbon gases and impurities such as carbon dioxide, vapour, sulfur, hydrogen, and nitrogen. In order to fulfill the pipeline and environmental standards, these impurities must be removed. The major cause of climate change is carbon and sulphur emissions such as CO2 and H2S. For these impurities, the pipeline requirements are: <2% CO2, <4ppm H2S and <0.1g/m3 H2O. Based on disadvantages in conventional processes, such as high energy consumption, complex processing and high capital cost, the development of membrane separation technique is highly compact, energetic, environmentally friendly, flexible, and possibly cost-effective than already well-established technologies. This study recommends the separation of CO2 from CH4 through membrane technology and introduces the cellulose acetate (CA) membrane in comparison with other established separation techniques including as absorption, adsorption, and cryogenic techniques and also suggests some ideas about current signs of progress in CA membranes such as enhanced permeability and selectivity. This study also emphasizes the modification of the cellulose acetate membrane and also outlines the essential distinctions, characteristics, and conditions of operation for the membrane process and other CO2 removal approaches.