Production Technology Of Carbon Molecular Sieve

Carbon molecular sieves (CMS) are porous materials used for gas separation and purification processes. They are typically prepared by carbonization of organic polymers or carbon precursors followed by activation to create a highly porous structure. Here's a general outline of the process:

1.Selection of Carbon Precursor: The first step is to choose a suitable carbon precursor. Common precursors include organic polymers such as phenolic resins, polyacrylonitrile (PAN), or various natural sources like coconut shells or wood.

2.Carbonization: The selected precursor material is heated in an inert atmosphere (like nitrogen or argon) at high temperatures (typically between 500°C to 1000°C) in a furnace. This process drives off volatile components and rearranges the molecular structure to form a carbon-rich material.

3.Activation: After carbonization, the resulting material is activated to create pores within the carbon structure. Activation can be done through physical or chemical methods.

a. Physical Activation: This involves exposing the carbonized material to an activating agent like steam or carbon dioxide at high temperatures. The gas reacts with the carbon surface, creating pores. Alternatively, physical activation can involve using a template material that is later removed, leaving behind pores.

b. Chemical Activation: In chemical activation, the carbonized material is treated with an activating agent, usually an oxidizing agent like phosphoric acid or potassium hydroxide. The acid or base reacts with the carbon, creating pores as well as surface functional groups.

4.Washing and Drying: After activation, the carbon material is washed thoroughly to remove any residual activating agents or byproducts. It is then dried to remove excess moisture.

5.Sizing and Shaping (Optional): Depending on the intended application, the CMS material may be crushed or ground to the desired particle size or shaped into specific forms like pellets or beads.

6.Characterization: The final CMS product is characterized using techniques such as nitrogen adsorption/desorption analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD) to determine its pore structure, surface area, and other properties.

It's important to note that the exact process parameters (such as temperature, time, and type of activating agent) can vary depending on the specific precursor material and desired properties of the carbon molecular sieve. Additionally, the choice of activation method (physical or chemical) also influences the final characteristics of the CMS material.