Enhanced carbon dioxide mineralization of industrial alkaline wastes through date palm waste-derived activated biochar

This study presents a sustainable approach for synthesizing activated biochar (BC) from date palm waste and enhancing its carbon dioxide (CO₂) capture capacity through integration with industrial alkaline waste, particularly ladle furnace slag (AW-LF). BC was produced via pyrolysis at 450 °C, 600 °C, and 750 °C and chemically activated using potassium carbonate (K₂CO₃) and hydrogen peroxide (H₂O₂). The materials were tested under CO₂ gas flow (10 % CO₂, 0.6 L/min, 1–2 bar, 22–25 °C) using a fluidized bed reactor. The highest CO₂ capture capacity reached 0.94 mmol/g with H₂O₂-modified BC at a 10 % BC-to-AW-LF ratio. The cumulative CO₂ uptake reached a maximum of 13.4 mol/L with K₂CO₃-activated BC, demonstrating approximately a 380 % increase compared to the performance of unmodified AW-LF slag. Kinetic analysis confirmed the modified Avrami model as the best fit (R² > 0.99), with the highest rate constant (K_ma = 0.0118) observed for H₂O₂-treated samples. The findings were validated through X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA), confirming stable CaCO₃ formation and enhanced porosity. Preliminary TGA results suggest up to 8 % weight loss due to CO₂ binding, confirming carbonation. The developed adsorbent is cost-effective, scalable, and derived from abundant agricultural and industrial wastes, supporting the circular economy and low-carbon technologies. A preliminary economic assessment estimated the cost of producing 100 g of hydrogen peroxide-modified BC at 6.6 AED (∼1.80 USD), highlighting its feasibility for large-scale applications.