1, solid surface adsorption refers to the interaction between the solid surface and gas or liquid molecules, resulting in the aggregation of gas or liquid molecules on the solid surface. This interaction usually includes physical adsorption and chemical adsorption.
2. Physical adsorption refers to the van der Waals force interaction between gas or liquid molecules on the solid surface, and there is no need for chemical reaction between the solid surface and gas or liquid molecules. Physical adsorption is usually non-selective, which means that different gas or liquid molecules can be adsorbed on the solid surface. Physical adsorption mainly depends on the physical properties of solid surface, such as surface roughness and polarity.
3. Chemical adsorption refers to the chemical reaction interaction of gas or liquid molecules on the solid surface, which requires a chemical reaction between the solid surface and gas or liquid molecules. Chemisorption is usually selective, which means that only molecules with specific chemical properties can be chemisorbed. Chemical adsorption mainly depends on the chemical properties of solid surface, such as surface functional groups and chemical bonds.
4. Surface energy: The free energy of the solid surface is lower than that of the bulk phase, so there is an inward pulling force, which leads to the decrease of the number of molecules near the surface layer and the formation of surface energy. Surface energy is one of the main driving forces of solid surface adsorption, which promotes the aggregation of gas or liquid molecules on solid surface, thus reducing surface energy.
5. Electronic structure: The electronic structure of the solid surface is different from the bulk phase, which makes the solid surface have unique chemical properties. The change of electronic structure can affect the adsorption properties of solid surface, such as the selectivity of chemical adsorption.
6. Intermolecular interaction: The interaction between gas or liquid molecules is also one of the important factors that affect the adsorption on the solid surface. For example, the van der Waals force interaction between different gas molecules can affect their adsorption degree and arrangement on solid surfaces.
7. Temperature and pressure: Temperature and pressure will also affect the adsorption performance of solid surface. With the increase of temperature or the decrease of pressure, the adsorption amount of gas or liquid molecules on the solid surface usually decreases.
The historical sources of chemisorption are as follows:
The historical origin of chemical adsorption can be traced back to19th century. At that time, scientists found that the solid surface had the ability to adsorb gas or liquid molecules through observation, and called it adsorption. However, there are still many puzzles about the description and explanation of adsorption phenomenon. Until the early 20th century, with the development of physical chemistry, adsorption theory was put forward and developed.
2. Chemical adsorption refers to the chemical reaction interaction of gas or liquid molecules on the solid surface, which requires the chemical reaction between the solid surface and gas or liquid molecules. Chemisorption is usually selective, which means that only molecules with specific chemical properties can be chemisorbed. Chemical adsorption mainly depends on the chemical properties of solid surface, such as surface functional groups and chemical bonds.