Porous material adsorbent is a solid material that can effectively adsorb certain components from gas or liquid, which have large specific surface area, suitable pore structure and surface structure, and strong adsorption capacity for adsorbates.Adsorbents generally do not undergo chemical reactions with adsorbates and medium, making them convenient to manufacture and easy to regenerate. They have excellent adsorption and mechanical properties.
The adsorption capacity of an adsorbent mainly comes from its porosity and the large number of active adsorption sites generated by its high specific surface area. When all the active sites in the adsorbent are occupied, its adsorption capacity reaches saturation. If the adsorbate occupies the active sites, this process is reversible and called adsorbent saturation. It requires heating, depressurization, and other regeneration methods to restore the adsorption performance of the already saturated adsorbent; If the substance occupying the adsorption site is not the adsorbate, but other substances that are difficult to detach from the adsorption site, the adsorption is irreversible and the adsorbent cannot be used again. This phenomenon is called adsorbent poisoning.
The adsorption capacity of adsorbents has an upper limit, and different adsorbents have different water tolerance. For example, calcium chloride desiccants can absorb moisture from the environment and gradually dissolve under normal humidity conditions, but soaking directly in water will only dissolve directly and cannot “capture” the moisture; Ordinary silicone gel has a good effect in adsorbing moisture in high humidity environments, but soaking in water can cause excessive and rapid water absorption, leading to cracking; 5A molecular sieve can separate nitrogen and water vapor in the air, but it has a particularly strong adsorption capacity for water. In high humidity environments, it quickly absorbs water and saturates, seriously affecting the separation efficiency of it for other substances.
Post time: Feb-27-2024