Application of Gas Adsorption Technology in Tobacco Industry
Updated 2023-01-17

The modern tobacco industry uses a large number of advanced technologies in the production process. For example, the physical structure of tobacco, such as specific surface area and true density, is analyzed by gas adsorption instruments to provide technical support for the optimization of process parameters.



Gas Adsorption Analyzer in the Tobacco Industry

Tobacco, generally refers to tobacco products that are cut into shreds, grains, flakes, ends, or other shapes, then added to auxiliary materials, fermented, stored, and ready for sale for smoking without being rolled, also known as shredded tobacco. The physical moistening properties of tobacco are important factors that affect its toughness, combustibility, aroma, and smoking comfort. When the moisture loss of tobacco is fast and the moisture content is low, it is easy to cause shattering during the production process and dryness and irritation during cigarette smoking. It was found that the differences in physical moisture retention properties of tobacco exist not only between different varieties but also between different parts and grades of the same variety of tobacco. Generally speaking, for the same type of tobacco, the moistening properties of upper and middle tobacco are better, and the lower tobacco is the worst; the higher the grade, the better the moistening properties of the tobacco.


Tobacco physical moisture retention refers to the ability of tobacco leaves to regulate the inhibition of moisture loss when tobacco is exposed to low moisture conditions. The equilibrium moisture content is a common index used in the tobacco industry to evaluate the physical moistening properties of tobacco. The physical moistening property of tobacco depends largely on its physical structure. From the physical structure, tobacco is mostly a porous material containing a large number of capillaries, and the pore structure not only affects the amount of water condensed inside tobacco but also affects the diffusion characteristics of water inside tobacco; the specific surface area, true density, pore capacity and pore size distribution of tobacco are important indicators of its physical structure. The pores are large in specific surface area and can strongly absorb water from the air. In addition, some researchers have inferred the moisture absorption curve of tobacco based on its pore size distribution; all of the above provide a theoretical basis for a comprehensive understanding of the self-moisture retention properties of tobacco.


In addition, the true density measurement can provide the basic physical data required for the analysis of heat and mass transfer properties and particle flow characteristics of tobacco materials, and provide technical support for the optimization of process parameters.


Gas adsorption is one of the most important methods for characterizing the physical properties of material surfaces. Using the CIQTEK V-sorb X800 series static volumetric specific surface and pore size analyzer, the specific surface area, pore volume and pore size distribution of the material can be obtained based on physical adsorption analysis; thus, the adsorption and water diffusion of the material tobacco, as well as the physical wettability properties can be evaluated on a fundamental basis. In addition, the CIQTEK true density analyzer can characterize the true density of the material, which in turn can be used to improve the tobacco growing and processing process.


Thus, it can be seen that the specific surface and pore size distribution and true density play a crucial role in the selection of tobacco types, the manufacturing process, and the final physical and sensory moistening properties.


Application of gas adsorption analyzer in tobacco waste


In the process of tobacco production and processing, a large amount of tobacco waste is generated, such as tobacco straw, moldy tobacco, and residual tobacco, among which tobacco straw is the main waste. However, most tobacco waste is currently disposed of by discarding, directly burying, or simply burning, which not only causes inefficient use of resources, but also serious environmental pollution problems. If the effective utilization of these tobacco wastes can be realized, it will produce huge economic benefits and good ecological benefits.


  Tobacco leaves, image from the Internet


It was found that the application of tobacco waste in the field of porous materials (mainly porous biomass and porous carbon materials) mainly includes two aspects: the application of tobacco materials themselves and the research in the field of carbon materials as raw materials. Among them, the derivatization of carbon materials and the application in the field of electrochemistry (supercapacitor) are two important paths for the high-value utilization of tobacco waste in the future. The main application directions are as follows.


1. Biochar material: prepared by direct carbonization method. The pore channels are mainly microporous and macroporous, with underdeveloped pores and relatively low specific surface area (<400 m2/g). It is commonly used as a soil conditioner, not only to increase organic matter or nutrients (C, N, P, K) in the soil but also in soil humidification, the surface element composition (H/C, O/C ratio), and specific surface area of biochar are two important factors affecting its hygroscopicity.


2. Porous carbon materials: The carbon materials prepared by the activation method (including the self-activation method) have well-developed pores and are mainly microporous. It is mainly used for the adsorption of organic dyes or heavy metals in wastewater. In terms of heavy metal adsorption, the adsorption properties of biochar are mainly used to reduce the bioavailability of heavy metals in soil by tobacco plants, and thus reduce the accumulation of heavy metal elements in plants.


3. Tobacco stalk based porous carbon materials: using tobacco stalk and other wastes, the prepared porous carbon materials have a high specific surface area and multi-level pore structure characteristics, which show excellent performance in the field of gas adsorption and supercapacitors.



CIQTEK High-performance Microporous Analyzer


CIQTEK UltraSorb X800 Series High-Performance Microporous Analyzer with Static Volume Method focuses on the surface characterization of microporous materials. The equipment is based on stainless steel piping, with a breakthrough design of VCR metal surface sealed sample tube to enhance the overall sealing of the gas piping flow process, with the advantages of long-time vacuum retention, ultra-low partial pressure ratio, constant temperature control, and multiple fluxes. It is capable of performing gas adsorption tests on porous carbon materials and analyzing parameters such as BET specific surface area, microporous pore capacity, and pore size distribution of the materials, which in turn can make a fundamental evaluation of the adsorption and catalytic performance of the materials.


  CIQTEK High-performance Microporous Analyzer UltraSorb X800


The following are examples of the characterization of porous carbon materials using CIQTEK UltraSorb X800 series high-performance microporous analyzers.

Figure 1 demonstrates that the specific surface area of the BET for porous carbon materials is 1870 m2/g. For microporous materials, the adsorption of nitrogen is closer to monolayer saturation adsorption, and the specific surface area of Langmuir is generally looked at and shown to be 2105 m2/g.
The N2 adsorption-desorption isotherm in Figure 2 is a class I isotherm, indicating a more abundant microporous structure.
Combined with the analysis of the pore size distribution diagram, the HK - pore size distribution in Figure 3 shows a more concentrated distribution of one micropore pore size near 0.66 nm, indicating that its most countable pore size is 0.66 nm.


   Figure 1 BET test results of porous carbon materials


Figure 2 N2 adsorption-desorption isotherm of porous carbon material



Figure 3 HK microporous pore size distribution of porous carbon material



Application of Electron Paramagnetic Resonance (EPR) Technology in Tobacco Industry


In addition, free radicals are one of the most important harmful substances in cigarette smoke, attacking cellular components directly and indirectly, leading to the oxidation of human tissues and cells, damaging lipids and proteins on cell membranes, and causing diseases such as cancer. EPR technology is the only technology that can directly detect and analyze free radicals, and in combination with free radical capture technology, it can identify the types of harmful free radicals in cigarette smoke, achieve a breakthrough in research methods, and further identify their structures, which can guide and develop corresponding free radical scavenging technologies.


CIQTEK EPR (ESR) Spectrometer