CARBON CAPTURE THROUGH THE PROCESS OF ADSORPTION USING AGRICULTURAL WASTES AS THE ADSORBENT (CORN COBS)
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Abstract
Climate change driven by increasing atmospheric CO₂ concentrations calls for urgent implementation of atmospheric CO2 reduction. However, adsorbents are mostly expensive and energy-intensive, especially for developing nations. Agricultural wastes, especially corn cobs, are a sustainable alternative due to their lignocellulosic composition, natural porosity,
and abundance as underutilized biomass. This study investigated the CO₂ adsorption potential of chemically activated corn cob-derived adsorbent through packed bed column experiments. Corn cobs were collected, processed, and activated using potassium hydroxide (KOH) at temperatures between 400-600°C. CO₂ gas was generated in-situ via CaCO₃-HCl reaction and
passed through glass columns (2.1 cm diameter, 5 cm bed height) at flow rates of 0.5-2.0 L/min. Four particle size ranges (100, 250, 500, and above 500 μm) were evaluated over 60- minute contact periods at ambient temperature (29±2°C).
Characterization via SEM-EDS revealed highly porous morphology with 90.05% carbon content and oxygen-containing functional groups favorable for CO₂ binding. The 100 μm particle size achieved the highest equilibrium adsorption capacity of 5,459 ppm·L/g, while 250 μm particles demonstrated optimal removal efficiency of 48.0%. Breakthrough analysis indicated that smaller particles delayed saturation, with 100 μm maintaining effectiveness beyond 45 minutes compared to 25 minutes for above 500 μm particles. Flow rate influenced performance, with reduced rates (0.5 L/min) compensating for larger particle sizes by increasing contact time. These findings reveal that corn bobs are a viable solution for carbon capture.
and abundance as underutilized biomass. This study investigated the CO₂ adsorption potential of chemically activated corn cob-derived adsorbent through packed bed column experiments. Corn cobs were collected, processed, and activated using potassium hydroxide (KOH) at temperatures between 400-600°C. CO₂ gas was generated in-situ via CaCO₃-HCl reaction and
passed through glass columns (2.1 cm diameter, 5 cm bed height) at flow rates of 0.5-2.0 L/min. Four particle size ranges (100, 250, 500, and above 500 μm) were evaluated over 60- minute contact periods at ambient temperature (29±2°C).
Characterization via SEM-EDS revealed highly porous morphology with 90.05% carbon content and oxygen-containing functional groups favorable for CO₂ binding. The 100 μm particle size achieved the highest equilibrium adsorption capacity of 5,459 ppm·L/g, while 250 μm particles demonstrated optimal removal efficiency of 48.0%. Breakthrough analysis indicated that smaller particles delayed saturation, with 100 μm maintaining effectiveness beyond 45 minutes compared to 25 minutes for above 500 μm particles. Flow rate influenced performance, with reduced rates (0.5 L/min) compensating for larger particle sizes by increasing contact time. These findings reveal that corn bobs are a viable solution for carbon capture.
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