CO2 Adsorption Performance and Mechanism of Biochar Derived from Various Biomass
Biochar derived from five kinds of biomass were prepared and characterized.The adsorption performance and mechanism of biochar for CO2 were investigated.The results showed that the specific surface area of biochar from coconut shell(YK)and pine wood(SM)was 1.99-2.90 times larger than that of corncob(YM),reed straw(LW)and coconut coat(YY)biochar.The adsorption capacity of YK and SM for CO2(108.78-118.89 mg/g)was also higher than those of YM,LW and YY(95.33-105.55 mg/g).In addition,the high S content(2.17%)and total basicity of YK also promoted its CO2 adsorption.The results demonstrated that the specific surface area,pore size,total basicity,and functional groups of biochar were all important factors affecting CO2 adsorption.When the pore difference is obvious,the influence of pore structure on CO2 adsorption will cover up the difference in alkalinity.Avrami model and Langmuir model fitted the adsorption well,indicating that the adsorption of CO2 on biochar was dominated by monolayer adsorption.Adsorption of CO2 by biochar was mainly a process of physical adsorption accompanied by chemical adsorption,which was greatly affected by temperature.When the temperature increased from 0℃to 65℃,the adsorption capacity of CO2 by biochar was decreased by 73.42%-77.14%.After 5 cycles of CO2 adsorption-desorption,the biochar still showed high reusability(85.26%-98.41%),which demonstrated that the biochar was a promising adsorbent for CO2 capture.
CO2 capture technologyBiocharAdsorptionGreenhouse gas removalAd-desorption cycles
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