Global warming and climate change caused by combustion of fossil fuels and other human activities which emit carbon dioxide into the atmosphere have raised concerns over carbon dioxide composition in the atmosphere and there have been calls to reduce carbon dioxide emission into the atmosphere. Conventional methods used for carbon dioxide separation from flue gas streams include adsorption, absorption, and cryogenics. However, these existing processes have become less attractive due to increase in the cost of energy, hence some flexible and reliable alternative processes with lower energy consumption and simple designs have to be developed. These properties are offered by membranes and have therefore drawn more attention for adoption in carbon dioxide and other gas separation processes. In this work CO2 separation performance of a single layer Pebax composite membrane have been enhanced by coating a layer of Polyethyleneoxide-block-Polysulfone-block-Polyethyleneoxide on Pebax composite membranes. This work presents helpful information which could be referenced by university students, graduate students and professionals in the field of natural gas sweeting and gas separations.