Exploring the carbon capture and sequestration performance of biochar-artificial aggregate using a new method.

Area of Science:

• Materials Science
• Environmental Engineering
• Chemical Engineering

Background:

• Developing new carbon sequestration methods is crucial for achieving carbon neutrality.
• Municipal solid household waste incineration bottom ash (MSWIBA) can be processed into artificial lightweight coarse aggregate (ALCA).
• Biochar possesses strong carbon capture capabilities.

Purpose of the Study:

• To investigate the synergistic carbon sequestration of biochar combined with ALCA.
• To quantitatively assess the ability of biochar-ALCAs to solidify low concentrations of CO2 in natural environments.
• To evaluate the impact of carbon sequestration on the physical and mechanical properties of biochar-ALCAs.

Main Methods:

• Combining biochar with ALCA derived from MSWIBA.
• Utilizing biochar's adsorption to attract CO2 into ALCA pores.
• Quantifying total carbon sequestration and sequestration rate using a self-designed CO2 concentration change test box.
• Investigating physical and mechanical properties before and after carbon sequestration.

Main Results:

• Biochar-ALCAs demonstrated good synergistic carbon sequestration ability.
• Total carbon sequestration reached 30.58-33.06 kg/ton.
• Carbon sequestration efficiency reached 70.2% (28 days) and 84.9% (56 days) in low CO2 environments (0.05% VOL).
• Water absorption decreased by 4.3%-13.9%, apparent density increased by 0.9%-2.8%, and strength increased by 4.3%-7.0% after carbon sequestration.

Conclusions:

• Biochar-ALCAs exhibit significant synergistic carbon sequestration potential.
• The material's physical and mechanical properties are substantially improved post-carbon sequestration.
• This study advances the development of recyclable cement-type composites for capturing and solidifying atmospheric CO2.