Biomass-derived Porous Carbon For Selective Adsorption Of CO₂/CH₄/N₂ In Coalbed Methane

As an ideal clean energy,low-enriched coalbed methane?CBM?is abundant and widely distributed in our country.Therefore,seeking a sustainable method for CBM exploitation can not only reduce the waste of resources and optimize the allocation of resources,but also alleviate the growing climate problems.In this paper,three green environment-friendly biomass-derived porous carbon materials are introduced,including soybean-based porous carbon?SAPC-5?,bamboo-based porous carbon?NBPC?and wool-based porous carbon?N-WAPC-3?.Above porous carbons are prepared by a simple chemical activation process using soybeans,disposable bamboo chopsticks and waste wool as precursors.The research contents as follows:?1?Porous carbon SAPC-5 was prepared by using soybean as the precursor and KOH as the active agent,with the specific surface area of 1866 m² g^-1 and pore volume of 0.45 cm³ g^-1.The adsorption selectivity of CO₂/CH₄ and CH₄/N₂ on SAPC-5 were2.88 and 4.21 respectively,by using Henry's law calculated from the initial slope.According to the ideal adsorption solution theory?IAST?,the selectivity for binary mixtures of CO₂/CH₄ and CH₄/N₂ with the mixture ratio of 5/95 were 5.05 and 5.03respectively,on SAPC-5 at 25? and 1 bar.?2?Nitrogen-doped porous carbon NBPC was prepared by using disposable bamboo chopsticks as precursor,KOH as active agent and urea as nitrogen resource,whose specific surface area is 1136 m² g^-1and nitrogen content is 7.71 wt%.The adsorption selectivity of CO₂/CH₄ and CH₄/N₂ on NBPC were 4.66 and 2.00 at 25? respectively,by using Henry's law calculated from the initial slope.According to the IAST,the selectivity for binary mixtures of CO₂/CH₄ and CH₄/N₂ with the mixture ratio of 5/95 were 10.09 and 2.45 respectively,on NBPC at 25? and 1 bar.?3?The N-doped hierarchical porous carbon N-WAPC-3 was prepared by using waste wool as precursor,KOH as active agent and urea as nitrogen resource,which possessed a specific surface area is 862 m² g^-1 and nitrogen content of 14.48 wt%.The adsorption selectivity of CO₂/CH₄ and CH₄/N₂ on NWAPC-3 were 3.8 and 7.6 at 25? respectively,by using Henry's law calculated from the initial slope.According to the ideal adsorption solution theory?IAST?,the selectivity for binary mixtures of CO2/CH4and CH₄/N₂ with the mixture ratio of 5/95 were 8.66 and 13.71 respectively,on N-WAPC-3 at 25? and 1 bar.