Fossil fuels continue to be the primary energy source, at least for this century. There are many technical options for separation and/or capture of CO2 from combustion flue gas and other industrial effluents. Other than geological injecting and direct ocean dump, forestation and ocean fertilization can be utilized to avoid or delay the carbon emission into atmosphere. Mineral carbonation should have limited applications. Amine absorption process is mature but has large room of improvement. Adsorption provides another option although it has many problems need to be addressed. Membrane separation processes provide several advantages over other conventional sepa- ration techniques; a membrane combining high flux, high selectivity and high stability is not realistic at this stage but mixed-matrix membranes provide hopes.
Although emerging technologies, such as zero-emission power plant, significantly reduce the complexity of sep- arating CO2 , many other industrial processes still emit substantial amounts of carbon dioxide which needs to be separated; CO2 separation and capture technologies will continue to evolve. Membrane process as energy- saving, space-saving, easy to scale-up, could be the future technology for CO2 separation.