Exploring the Production Process of Carbon Molecular Sieve: From Raw Materials to High-Performance Adsorbents

Carbon molecular sieve is a carbon-based material with a microporous structure, widely used in gas separation, air purification, and industrial waste gas treatment due to its excellent adsorption properties and selective separation capabilities. Below is the typical production process of carbon molecular sieve:

1. Raw Material Selection
The raw materials for carbon molecular sieve are typically organic compounds rich in carbon, such as lignin, cellulose, polyacrylonitrile (PAN), and phenolic resin. Selecting suitable raw materials is crucial for producing high-performance carbon molecular sieve.

Lignin: Derived from plant fibers, it is cost-effective and widely available.
Polyacrylonitrile (PAN): Offers good thermal and chemical stability.
Phenolic Resin: Easy to shape with controllable pore structure.
2. Precursor Preparation
The selected organic raw materials are processed into precursors through dissolution, spinning, or molding. The shape and structure of the precursor directly influence the final properties of the carbon molecular sieve.

Spinning Method: Dissolved raw material solution is spun into fiber-shaped precursors.
Molding Method: Powdered raw materials are pressed into block or pellet-shaped precursors using molds.
3. Carbonization and Activation
The precursors undergo high-temperature carbonization and subsequent chemical or physical activation to form microporous carbon molecular sieve.

Carbonization:
Heated to 600°C–1000°C in an inert atmosphere (e.g., nitrogen or argon).
Non-carbon elements are removed at high temperatures, forming an initial carbon skeleton.
Activation:
Chemical activation (e.g., using phosphoric acid or zinc chloride) or physical activation (e.g., using carbon dioxide or steam) is performed.
Activation further opens up the pores in the carbon skeleton, creating a uniform microporous structure.
4. Shaping and Processing
Activated carbon molecular sieve is often shaped and processed to meet the requirements of various applications.

Pellet Production: Activated carbon materials are crushed and screened to produce particles of different sizes.
Honeycomb Structure: Molded or extruded into honeycomb-shaped carbon molecular sieve for gas filtration and purification.
5. Surface Modification
To enhance the adsorption performance and selectivity of the carbon molecular sieve, surface modification can be performed.

Chemical Modification: Functional groups (e.g., hydroxyl, amino, carboxyl) are introduced to improve adsorption capacity for specific gas molecules.
Physical Modification: Surface properties are altered through ion implantation or plasma treatment to improve pore structure and chemical activity.
6. Performance Testing and Quality Control
Finally, the produced carbon molecular sieve undergoes performance testing, including pore structure analysis, adsorption capacity measurement, and selective separation experiments, to ensure product quality meets standards.

Conclusion
The production process of carbon molecular sieve involves raw material selection, precursor preparation, carbonization, activation, shaping, surface modification, and performance testing. Each step requires precise control of process parameters to ensure the pore structure, adsorption performance, and stability of the final product. With technological advancements and growing market demands, the production process of carbon molecular sieve continues to evolve and innovate.