Influencing Factors on the Performance of Nabok Molecular Sieve Rotating Wheels - The Effects of Adsorbate and Adsorbent

The molecular sieve rotor is a honeycomb corrugated structure made of ceramic fiber paper as the carrier, and different adsorbents are loaded to adsorb and concentrate VOCs, thereby achieving the purpose of organic waste gas treatment. The performance of the molecular sieve rotor is mainly affected by the adsorbate, the adsorbent, and the operating parameters of the molecular sieve rotor. This article mainly analyzes the influence of the adsorbate and the adsorbent on the performance of the molecular sieve rotor.

1. Influence of Adsorbate

1.1 Boiling Point

The boiling point of the adsorbate is mainly reflected in the vapor pressure. Since adsorption is mainly a condensation phenomenon at the surface of the micropores, the higher the boiling point, the easier the condensation occurs and the greater the potential energy of adsorption. 

1.2 Molecular Size

If the gas molecule is too large, it may not be able to diffuse into the pores or the diffusion rate is too slow, which may affect the adsorption effect, especially in low-pressure adsorption. However, from another perspective, if the adsorbate molecule can enter the pores of the adsorbent, the larger the molecule, the greater the adsorption force with the adsorbent, and the stronger the adsorption capacity. 

1.3 Adsorbate Concentration

The higher the concentration of the adsorbate in the gas phase, the greater the adsorption amount, but an increase in concentration will inevitably cause the adsorbent to reach saturation earlier and make the regeneration operation more troublesome. 

1.4 Polarity or Molecular Structure

The functional groups and polarity of the adsorbate will affect the adsorption situation. The functional groups are likely to react with the adsorbent, resulting in chemical adsorption, and an irreversible phenomenon. The size of the molecular dipole moment is used to measure the polarity of the molecule. The larger the dipole moment, the greater the polarity of the molecule, and a dipole moment of zero indicates a non-polar molecule. 

2. Influence of Adsorbent

2.1 Specific Surface Area

Specific surface area is the first factor in judging the quality of the adsorbent. Since adsorption is a surface effect, the larger the specific surface area, the more adsorption sites it can provide, and thus the higher the saturated adsorption capacity. 

2.2 Size Distribution of Pores

The size and distribution of pores also have a significant impact on the adsorption capacity of the adsorbent. Theoretically, small pores have a greater effect on the condensation of vapor, and the influence of pore size distribution is manifested in both high and low-pressure adsorption. In high-pressure adsorption, multi-layer adsorption can be caused, and pores with larger sizes play an important role. In low-pressure adsorption, the adsorption of micropores is more obvious. 

2.3 Physical and Chemical Properties

The polarity of the adsorbent has a certain influence on the adsorption capacity. Non-polar adsorbents have a higher affinity for non-polar organic molecules, while polar adsorbents have a higher affinity for polar molecules. Since the surface of the molecular sieve is polar, it has a better adsorption effect on polar adsorbates.