以广西百色油茶壳为原料、磷酸为活化剂,分别采用马弗炉加热和微波加热炭化-活化一步法制备了油茶壳基中孔活性炭,测得其碘、亚甲基蓝吸附值分别为969.87mg·g^-1、279.55 mg·g^-1和1015.34mg·g^-1、225.56 mg·g^-1。使用物理吸附仪在77.4 K下测定其N2吸附-脱附等温线,相对压力在0.4~1,氮吸附曲线具有明显的脱附滞后环。采用αs-plot法研究孔结构,BET法与BJH法计算比表面积和孔径分布,结果表明两种活性炭中孔率分别为75.3%、84.3%,孔径集中分布在1.4~5 nm。探讨了微波活化对活性炭孔结构的形成的影响,认为与传统活化相比,微波活化活性炭所含口小腔大型孔更多。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)对活性炭进行表征,分析了活性炭的表面形貌和微观结构。
Using camellia oleifera shell from Guangxi Baise as raw material, mesoporous activated carbons (ACs) were prepared by one-step carbonization-activation method with H3PO4 as activator under traditional thermal heating (hAC) and microwave heating (mwAC), respectively. The iodine and methylene blue (MB) adsorption values of hAC are 969.87 mg·g^-1 and 279.55 mg·g^-1; while the iodine and MB adsorption values of mwAC are 1015.34 mg·g^-1 and 225.56 mg·g^-1. The nitrogen adsorption-desorption isotherms of the prepared ACs with a clear desorption loop at 0.4〈p/p^0〈 1 was obtained at 77.4 K by using the physical adsorber. The porous structure of the ACs was investigated by nitrogen adsorption isotherms on the bases of Q-plot and Barrett-Joyner-Halenda (BJH) methods. The results show that they have a narrow pore size distribution within 1.4-5 nm, and the mesoporous ratio of the hAC and mwAC are 75.3% and 84.3%, respectively. The effect of microwave activation on the formation of the porous structures in the mwAC was discussed. And it was found that the mwAC contains more numbers of pores with "small entrance-large body" than hAC. The scan electric microscope (SEM) and X-ray diffraction (XRD) were also used to investigate the morphology and crystallite structure characteristics of the ACs.