Energy production and use account for two-thirds of the world's greenhouse-gas (GHG) emissions, In 2013, CO2 accounted for about 82% of all U, S, greenhouse gas emissions from human activities.1 Separation and capture of CO2, and its conversion to useful chemicals collectively is an important and promising way to address this urgent environmental challenge.
In 2010 the United States alone used 24.64 trillion cubic feet of natural gas. Such consumption of natural gas drives a worldwide market for new natural gas separation equipment of ˜$5 billion per year.2 In the production of natural gas, the natural gas or methane often has to be separated from other gases in order to enable the methane to be refined to a usable concentration or purity. Many different types of separation technologies are currently utilized to refine the methane from the other vases commonly produced along with methane, such as carbon dioxide.
For example, landfill gas, which is produced from municipal solid waste at landfills through microbial digestion, has been long-touted as a promising energy source. However, landfill gas is approximately 50% methane and 50% CO2, and CO2 removal from the methane remains a big hurdle to make this a potent, money-making energy source.
However, currently, amine scrubbers and cryogenic phase change processes are the most widely used technologies to separate CO2 from methane/CO2 gas mixtures. An amine scrubber uses asp alkanol amine solution in operation, which requires energy to regenerate the materials in the process and the amine solution is corrosive as well, rendering the material difficult to, handle.3 Further, the cryogenic gas-to-liquid phase change is highly energy- and capital intensive.4 
In addition, a microbial pathway of conversion of CO2 to isoprene gas has recently been developed, with isoprene being a promising energy fuel.5, 6 However, the difficulty is how to separate the unreactive CO2 from the target product, isoprene, after completion of the process.
Thus, it is highly desirable to develop a method and system for removing CO2 from other gases, such as methane and isoprene, in a manner that does not require significant energy expenditure in order to more efficiently produce a useable gas stream(s) for energy production.
Recently, porous solid sorbents have emerged as promising materials to perform CO) capture and separation, heterogeneous catalysis, and sensing applications. In 2007, separation processes utilizing a membrane had less than 5% of this gas separation equipment market, almost all of which is applied toward the removal of carbon dioxide.2 The US membrane industry alone was forecast to spend $5.4 billion in 2016 alone as membrane technology continues to compete against typical absorption processes.7 However, current membrane separation technology, systems and processes are not capable of efficiently and reliably removing CO2 from a combined gas stream in order to produce an acceptable gas stream for energy production.