Activated carbon from olive kernels in a two-stage process: industrial improvement

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Activated carbons are crucial adsorbents for various applications.
• Olive kernels represent an abundant, underutilized lignocellulosic waste material.
• Developing sustainable methods for activated carbon production is environmentally significant.

Purpose of the Study:

• To investigate the preparation and adsorptive properties of activated carbons derived from olive kernels.
• To compare laboratory-scale chemical activation with pilot-scale physical activation.
• To evaluate the potential of olive kernel-based activated carbons as adsorbents.

Main Methods:

• Two-stage pyrolysis-activation process: laboratory-scale with KOH (chemical activation) and pilot-scale with H2O-CO2 (physical activation).
• Pyrolysis at 800°C followed by activation at 970°C.
• Characterization using N2 adsorption (BET surface area), methyl-blue adsorption, and Scanning Electron Microscopy (SEM).

Main Results:

• Activated carbons produced showed increasing surface area and methyl-blue adsorption with burn-off.
• Maximum BET surface areas reached 1000-1200 m²/g (industrial scale, physical activation) and 3049 m²/g (laboratory scale, KOH activation).
• Pore structure evolved from micropores to a mix of micro- and mesopores with increased activation.

Conclusions:

• Olive kernels can be effectively converted into high-surface-area activated carbons.
• The adsorptive capacity, particularly for methylene blue, is comparable or superior to commercial activated carbons.
• This study highlights a sustainable route for valorizing olive waste into valuable adsorbent materials.