We all know that activated carbon can adsorb toxic gases because of its well-developed pores. One important indicator that determines whether its pores are well-developed is the specific surface area. How many square meters of internal pores does it represent per gram of activated carbon?

From the perspective of testing principles, specific surface area testing methods can be divided into two categories: dynamic chromatography and static volumetric methods. Dynamic chromatography is a method of measuring the adsorption peak area (adsorption amount) of the sample to adsorbate molecules (N2) by placing the powder sample in a U-shaped sample tube and allowing a mixed gas containing a certain proportion of adsorbate gas to flow through the sample cell. The TCD thermal conductivity cell is used to detect the changes in gas concentration before and after adsorption, and the specific surface area value of the sample is calculated by comparing it with the adsorption peak area of a standard sample; The static capacity method is to place the powder sample to be tested in a sealed sample tube of a certain volume, inject a certain pressure of adsorbate gas into the sample tube, and calculate the adsorption amount of adsorbate molecules (N2) by the tested sample based on the pressure change before and after adsorption. Based on the adsorption amount and the relative pressure at adsorption equilibrium, the adsorption desorption isotherm is accurately obtained, and the specific surface area and external specific surface area of the sample are calculated using theoretical models such as multi-point BET, Langemuir, t-polt, etc. Bamboo charcoal without activation treatment has a very low specific surface area, only about 200m2 per gram. Ordinary coconut shell activated carbon can reach around 800m2. And for high-quality coconut shell activated carbon, this indicator can exceed 1000m2. This means that as long as the activated carbon is the size of a coin, the internal adsorption area can reach the size of a standard foot field.