CO2-grabbing biochar delivers a stronger, denser cement mix

A recent study from Hefei University of Technology reveals that modified biochar, derived from corn-straw waste, can both capture CO₂ within cement and enhance the material’s strength and durability. Cement production is a major contributor to global CO₂ emissions, accounting for nearly 8%, and current carbon capture methods are often impractical or costly. The researchers focused on biochar’s internal sedimented particles (SP), which exhibit significantly higher CO₂ adsorption than untreated biochar. By applying controlled pyrolysis and alkali modification, they produced a biochar variant (notably MBC500) that promotes internal carbonation and calcite formation, densifying the cement microstructure and improving compressive strength. Extensive testing—including BET surface area analysis, FTIR, Raman spectroscopy, and mechanical tests—showed that alkali treatment refines biochar’s micropores, enhancing CO₂ adsorption sites despite reducing overall surface area. The SP component demonstrated superior adsorption capacity, with kinetic modeling indicating rapid physical adsorption combined with some