煤基活性炭比表面积与碘吸附值相关性研究

Research on the correlation between specific surface area and iodine adsorption value of coal-based activated carbon

为快速测量煤基活性炭比表面积和孔隙结构等性能指标,通过分析活性炭的碘吸附值与比表面积、孔结构之间的关系,明确BET与碘吸附值之间的相关性。结果表明,碘吸附值在50~800 mg/g时,碘吸附值与比表面积之间具有良好的线性关系,拟合度达0.933,利用碘吸附值可快速高效估算比表面积和微孔结构,还可用来预测BET,但相对吸附压力(P/P0)和常数C选择不当,将导致比表面积测量不准确;碘吸附值的大小主要表征了活性炭微孔0.8~1.2 nm孔隙的发达程度;碘分子在微孔中进行单层吸附符合由致密堆积的六方晶格组成的表面覆盖模型。碘吸附值能够实现煤基活性炭比表面积和孔结构的快速分析。

in order to achieve the rapid measurement of specific surface area and pore structure of coal-based activated carbon, the rela- tionship between iodine value and specific surface area, pore structure of activated carbon were analyzed. The correlation between BET and iodine value were determined. The results show that there is a good linear relationship between iodine adsorption and specific surface area when the iodine adsorption value ranges from 50 to 800 mg/g. It is a fast and efficient method to estimate specific surface area and micro- pore structure by using iodine adsorption value, and it can be used to predict the BET. However, the improper selection of relative adsorp- tion pressure（ P/Po ） and C constant will lead to inaccurate measurement of specific surface area. The iodine adsorption value mainly char- acterizes the development pores of O. 8-1.2 nm of activated carbon. The iodine molecules are monolayer adsorbed in microporous, which is in line with a surface-covered model consisting of a hexagonal lattice of dense packing. Therefore,iodine adsorption value can be used to rapidly analyze the specific surface area and pore structure of coal-based activated carbon.