Method for determining tobacco leaf specific surface, pore volume and pore diameter

Abstract

The invention relates to a method for determining the specific surface, pore volume and pore diameter of a tobacco leaf, belonging to the technical field of research on physical characteristics of the tobacco leaf. The method provided by the invention is carried out according to the BET (Brunauer-Emmett-Teller) test theory and comprises the following steps: a, preparing test samples and testing; b, measuring multilayer adsorption capacities of three groups of test samples under different nitrogen partial pressures according to a BET equation, taking P / P0 within the range of 0.05-0.25 as an X axis, taking a count formula (described in the specification) as a Y axis, drawing according to the BET equation and carrying out linear fitting to obtain the slope and intercept of a straight line, thus the Vm value is solved and the specific surface area of the tested sample is calculated; c, determining the pore volume, wherein single point nitrogen adsorption capacity when the P / P0 is 0.95 is namely the pore volume of material; and d, calculating the pore diameter by the specific surface area and the pore volume according to the formula (described in the specification). The method in the invention has the advantages of safety and simplicity, and the determined indexes of the specific surface, the pore volume and the pore diameter of the tobacco leaf can represent the adsorption capacity and identity of the tobacco leaf.

Description

A method for measuring specific surface, pore volume and pore diameter of tobacco leaves technical field The invention relates to a method for measuring the specific surface, pore volume and pore diameter of tobacco leaves, and belongs to the field of measuring the physical indexes of tobacco leaves. Background technique The specific surface area refers to the total area of ​​a unit mass of material, and the unit is m2 / g. Pore ​​volume refers to the total volume of pores per unit mass of porous solid, called pore volume, and the unit is cm3 / g. Pore ​​diameter refers to the shape and size of the pores in a porous solid, which is extremely irregular. It is usually regarded as a cylinder and its radius is used to represent the size of the pores, in nm. The pore size distribution with pore radius below 10nm was measured by gas adsorption method. The BET test theory is based on the multi-molecular layer adsorption model proposed by Brunauer, Emmett and Teller, and deduces th...

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