Valorization of Moroccan Alfa Grass through Pyrolytic Conversion to Biochar for Atmospheric CO₂ Capture

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Valorization of agricultural waste like Alfa grass is crucial for sustainable material development.
• Biochar production offers a pathway for carbon sequestration and environmental remediation.
• Optimizing biochar properties for specific applications, such as CO2 capture, requires detailed investigation.

Purpose of the Study:

• To investigate the production of biochar from Alfa grass for CO2 capture.
• To correlate biochar properties with preparation conditions (temperature, atmosphere).
• To evaluate the CO2 adsorption performance and kinetics of the produced biochar.

Main Methods:

• Alfa grass biochar was produced via slow pyrolysis in tubular (N2) and muffle (air) furnaces at 300, 400, and 500 °C.
• Comprehensive characterization included FTIR, Raman, SEM, TGA, BET, elemental analysis, and density measurements.
• CO2 adsorption experiments were conducted at 30 °C and 1 bar, followed by kinetic analysis.

Main Results:

• Biochar produced under N2 atmosphere exhibited significantly higher CO2 uptake (approx. 34% increase) compared to air-treated biochar.
• Optimal adsorption performance was linked to the interplay of micropores, mesopores, and surface chemistry, rather than solely surface area.
• Kinetic analysis indicated that selected biochar samples followed a pseudo-second-order adsorption model (R2 ≈ 0.99), signifying fast adsorption.

Conclusions:

• Slow pyrolysis under nitrogen is an effective method for producing high-performance CO2 capture biochar from Alfa grass.
• The structural and chemical properties influenced by pyrolysis conditions are key determinants of CO2 adsorption capacity.
• Alfa grass-derived biochar shows promise for efficient and rapid CO2 capture applications.