摘要
在空气、氮气和水蒸气3种气氛下,以杉木为原料分别制备了4种磷酸活化法活性炭。考察了活性炭的表面官能团和孔隙结构对亚甲基蓝吸附能力的影响。根据氮气吸附等温线分析了活性炭的孔隙结构,采用Boehm酸碱滴定方法测定了活性炭的表面官能团含量,并测定了活性炭的亚甲基蓝吸附等温线。结果表明：活性炭的孔隙越发达,其亚甲基蓝吸附能力越强。提高活性炭的表面官能团含量,一方面有利于亚甲基蓝分子以更紧密的排列方式被活性炭所吸附,促进吸附;另一方面,对活性炭中吸附亚甲基蓝分子有效的孔隙可能产生屏蔽作用,不利于吸附。当活性炭的表面官能团含量提高时,对于中孔发达的活性炭,前者占优势,亚甲基蓝吸附量增加;而对于微孔活性炭,后者则占优势,亚甲基蓝吸附量减少。
Activated carbons of China fir（Cunninghamia lanceolata） wood origin were prepared from phosphoric acid activation in atmospheres of air, nitrogen and steam respectively, and the effects of the properties of activated carbon on the adsorption capacity of methylene blue were investigated. Porous texture of activated carbon was analyzed based on the nitrogen adsorption isotherms. Surface functional groups were determined by the Boehm method, and the adsorption isotherms of methylene blue on the activated carbons were measured. The results show that activated carbon with more developed porosity has higher adsorption capacity of methylene blue. Surface functional groups on activated carbons, especially strong acid groups, play two roles in adsorbing methylene blue. Surface functional groups facilitate the arrangement of methylene blue molecules at a more compact way on activated carbon and thus produce a positive effect on the adsorption of methylene blue. On the other hand, they can screen to some degree parts of pores that are originally accessible to methylene blue molecules and thus suppress the adsorption. Consequently, an increased concentration of surface functional groups may produce an increase in the adsorption capacity of methylene blue for the activated carbon with developed mesopores because the former role predominates, on the contrary, a decrease for the microporous activated carbon because the latter role predominates.
出处
《林产化学与工业》
EI
CAS
CSCD
北大核心
2010年第4期1-6,共6页
Chemistry and Industry of Forest Products
基金
国家自然科学基金资助项目(30671651,30972317)
关键词
磷酸
活性炭
亚甲基蓝
吸附
phosphoric acid
activated carbon
methylene blue
adsorption
