不同活化方法对开心果壳活性炭的孔结构影响

以开心果壳为原料制备活性炭,通过在-196 ℃下测定活性炭的氮气吸附等温线,探讨ZnCl₂法、KCl法以及ZnCl₂-KCl-H₂O联合活化法对活性炭孔结构的影响.研究表明:ZnCl₂法制备的开心果果壳活性炭以微孔为主,采用40%ZnCl₂溶液浸渍,在500 ℃下活化1.5 h后得到的活性炭的比表面积为630 m²·g^-1;单独KCl活化法不能起到较好的活化效果;对于ZnCl₂活化法和KCl活化法,增加水蒸气活化都能增强活化效果,尤其对KCl活化的增强效果最为明显,使其比表面积增大近9倍,但其孔结构仍是微孔为主;ZnCl₂-KCl-H₂O联合活化法能有效增加活性炭的中孔,采用40%ZnCl₂和6%KCl溶液浸渍,在900 ℃下活化1.5 h后得到的活性炭的中孔添加量为0.10 cm³·g^-1,比表面为740 m²·g^-1,中孔孔径集中在4 nm.

Effect of Different Activation Methods on the Pore Structure of Activated Carbons Prepared from Pistachio Shells

Activated carbons were prepared from Pistachio nut shells by using ZnCl₂, KCl and ZnCl₂-KCl-H₂O as activating agents separately, and were tested at -196 ℃ to obtain the N₂ adsorption isotherms to get the pore structure properties. It showed that the pore structure of ZnCl₂-activated carbons was mainly micropore, and the max BET area of the activated carbons was 630 m²·g^-1 when impregnated with 40% ZnCl₂ and activated at 500 ℃ for 1.5 h. While using KCl as activating agent alone, it could be hardly to obtain good activation effect. The activation effect was improved by introducing vapor as the activating gas by using ZnCl₂ and KCl as activating agent, which played a much more important played a much more important role on formation of new pores, especially for the method of KCl, and its BET area increased by about 9 times, and the pore structure was mainly micropore. Mesopore was effectivlely donated by using ZnCl₂-KCl-H₂O as a mixed activating agent. Under the condition of impregnating with 40% ZnCl₂ and 6% KCl, the BET area of the activated carbons was 740 m²·g^-1, as well as the mesoporous volume was 0.10 m³·g^-1 and the major pore size of mesopores was about 4 nm when activated at 900 ℃ for 1.5 h.