活化剂种类对生物质活性炭理化特性的影响

EFFECTS OF DIFFERENT ACTIVATORS ON PHYSICOCHMICAL PROPERTIES OF ACTIVATED CARBON FROM BIOMASS

采用KOH、K_(2)CO_(3)和ZnCl_(2)为活化剂,椰壳、竹子、杨木和棉秆为原材料制备活性炭,研究不同活化剂对生物质热解活化产物及活性炭理化特性的影响。结果表明,KOH活化时,生物质的固液气三相比例均衡,CO体积产量最高,活性炭的表面官能团稳定性最好,骨架破碎,微孔结构发达,微孔面积可达749.90 m^(2)/g。K_(2)CO_(3)活化时,生物质活化气体产率最高,可达68.96%,活性炭介孔结构发达,比表面积、总孔体积最大,分别可达1449.53 m^(2)/g和0.93 cm^(3)/g。ZnCl_(2)活化时,H2体积产量大于40%,活性炭产率最高达48.48%,活性炭的固定碳含量、C转化率、石墨化程度最高,孔洞分布整齐,比表面积和总孔体积低于K_(2)CO_(3)活性炭。

Activated carbons are prepared from poplar wood,coconut shell,cotton stalk and bamboo by using KOH,K_(2)CO_(3)and ZnCl_(2)as the activators.The effects of different activators on the physicochemical properties of pyrolysis products and activated carbons are investigated.The results show that when KOH is used as the activator,there is a balance in the proportions of three-phase products(gas,liquid,and solid)from the biomass,and the volume yield of CO is the highest;besides,the activated carbon has the highest stability of surface functional groups but with broken skeleton,and exhibits well develop microporous structures(749.90 m^(2)/g).The activation by K_(2)CO_(3),leads to the highest gas yield(up to 68.96%)of the biomass,and the activated carbon has highly developed mesoporous structures as well as the largest specific surface area(1449.53 m^(2)/g)and total pore volume(0.93 cm^(3)/g).Under the activation by ZnCl_(2),the volume yield of H_(2) can exceed 40%,and the yield of activated carbon is the highest(up to 48.48%).In addition,ZnCl_(2)activation results in the highest fixed carbon content and carbon conversion rate,the activated carbon has smaller specific surface area and total pore volume than obtained under the activation of K_(2)CO_(3),and exhibits a regular pore distribution and the highest graphitization degree.