Drying enables multiple reuses of activated carbon without regeneration

Area of Science:

• Environmental Chemistry
• Materials Science
• Chemical Engineering

Background:

• Traditional activated carbon regeneration via high-temperature oxidation degrades adsorbent quality, increases costs, and harms the environment.
• Developing sustainable and cost-effective methods for activated carbon reuse is crucial for industrial adsorption processes.

Purpose of the Study:

• To propose and evaluate a simple drying process for regenerating spent activated carbon for dye removal.
• To assess the feasibility and benefits of this drying method in both batch and continuous adsorption systems.

Main Methods:

• Spent activated carbon was regenerated using a simple drying process.
• The regenerated activated carbon was tested in batch and continuous adsorption modes using methyl orange (MO) and methylene blue (MB) as adsorbates.
• Adsorption capacity, reusability, and adsorbate leaching were evaluated.

Main Results:

• Activated carbon regenerated by drying could be reused seven times in batch mode, achieving cumulative adsorption capacities of 1005.3 mg/g for MO and 954.8 mg/g for MB.
• In continuous fixed-bed column experiments, the dried activated carbon was reused over three times without significant leaching of adsorbed dye molecules.
• The drying method reduced fresh activated carbon consumption by at least 51.5% and enhanced adsorbate recovery.

Conclusions:

• A simple drying process is a viable and eco-friendly alternative to traditional high-temperature oxidation for activated carbon regeneration.
• This method significantly reduces operational costs, minimizes environmental impact, and improves the efficiency of industrial adsorption processes.
• The regenerated activated carbon demonstrates high adsorption capacity and stability, making it suitable for repeated use in dye removal applications.