Activated Carbon Regeneration: How to “Recycle” Adsorption Capabilities?

Thermal Regeneration: The Established and Efficient Method

Thermal regeneration is the most widely used industrial method, capable of restoring up to 90% of the activated carbon’s original adsorption capacity.

The Process Includes Several Stages:

1. Drying and Desorption – The carbon is heated in a rotary kiln at high temperatures within an inert atmosphere, preventing oxidation and releasing the adsorbed gases.
2. Cooling and Preliminary Packaging – After heating, the carbon is cooled and inspected for quality and mechanical integrity.
3. Sieving and Final Packaging – Carbon fines and waste are separated, and the high-quality carbon is repackaged for reuse.

Advantages:

• Restores up to 90% of the carbon’s adsorption capacity in the first cycle.
• Preserves the carbon’s structure, ensuring high-quality reuse.
• Suitable for most types of activated carbon and a wide range of applications.

Disadvantages:

• High energy consumption due to extended heating periods.
• Requires advanced gas treatment systems, leading to elevated operational and investment costs.
• Efficiency diminishes with successive regenerations, primarily due to structural damage and pore blockage.

Steam Regeneration: A Cost-Effective Method with Limited Efficiency

Steam regeneration involves passing hot steam through the activated carbon, causing the release of some adsorbed contaminants.

Advantages:

• More energy and cost-efficient compared to thermal regeneration, as it requires less energy and does not need complex gas treatment facilities.
• Suitable for small systems and straightforward applications.
• More environmentally friendly, as using steam reduces pollutant emissions relative to thermal methods.

Disadvantages:

• Limited efficiency – even under ideal conditions, steam regeneration restores at most 50% of the carbon’s original adsorption capacity.
• Not suitable for applications requiring high adsorption levels.
• The heating and cooling process may cause carbon particle breakage, leading to loss of active material.
• Less appropriate for large-scale industrial use.

Biological Regeneration: Merging Science and Nature

Biological regeneration employs microorganisms to decompose organic compounds adsorbed on the carbon.

Advantages:

• Environmentally friendly and cost-effective to operate.
• Uses microorganisms to break down contaminants into water (H₂O) and carbon dioxide (CO₂).
• Suitable for small-scale and specific applications.

Disadvantages:

• A slow process, dependent on temperature and contaminant type.
• Ineffective for large-scale industrial applications or complex pollutants.
• Limited to the bacteria’s ability to act only on the carbon’s surface.

Additional Regeneration Methods

• Solvent Regeneration: Utilizes solvents to release specific contaminants. Primarily suitable for processes with high contaminant concentrations and low boiling points.
• Wet Oxidation Regeneration: Oxidizes contaminants in a liquid phase using oxygen or air at high temperatures and pressures. This method has limited efficiency (~45%) and high energy costs.

Activated Carbon Regeneration with Colligo-Tech

Regenerating activated carbon is a smart solution for environmental conservation and cost reduction. Selecting the appropriate regeneration method depends on the contaminant type, budget, and client requirements. It is crucial to ensure the regeneration process is conducted professionally and effectively.

Unfortunately, in some cases, “regenerated” carbon fails to restore the desired adsorption capabilities and may even harm the environment.

We recommend requesting analyses of the activated carbon after regeneration.

Colligo-Tech offers expert consultation and customized solutions to meet the specific needs of your system.