Their results indicated that the
highest adsorbance of CH4 (1 mmol/g) could be obtained over
a carbon sieve at 30 ◦C and 200 kPa. Shen and co-workers
studied the separation of a trace amount of CO2 from mixed
gases systematically and they reported that the activated carbons
with high specific surface area can solve this problem
successfully [10,11]. Ottiger and co-workers investigated the
competitive adsorption of CO2 and CH4 on the activated carbons
prepared by dry coals and found that the activated carbons
possessed high CO2 adsorption capacity [12]. The main
factor affecting the adsorption capacities of CO2 and CH4 on
activated carbons is the textural properties of the activated
carbons. Meanwhile, the textural properties of the activated
carbons can be regulated by the preparation conditions and
the carbon precursors [13]. To our knowledge, there are few
reports on the application of activated carbons, prepared by
coconut-shells, to separate/concentrate greenhouse gases.