Three kinds of activated carbons have been prepared by
different activated methods using coconut-shells as carbon
precursors. The activated carbons are amorphous and rarely
adsorbed organic groups on the surfaces. The CO2 and CH4
adsorption capacities of K-AC are satisfied to the requirement
of separation/concentration greenhouse gases by PSA. CH4 is
hardly adsorbed on P-AC. However, the CO2 adsorption capacity
can reach 2.55 mmol/g at 25 ◦C and 200 kPa. P-AC
may be an excellent adsorbent to purify natural gas with trace
CO2 by PSA technology.