Direct air capture of CO2 by KOH-activated bamboo biochar

Direct air capture (DAC) of CO2 is considered one of the most promising carbon capture methods to reduce ambient CO2 concentration for climate change mitigation. Biochar represents an attractive adsorbent for DAC because it is environmentally friendly and cost-effective. In this work, KOH-activated bamboo biochar shows the CO2 capture capacity of 3.49 mmol g-1 (25 degrees C, 1 bar), and it is used as an adsorbent to perform direct air capture using a fixed-bed reactor with an ambient CO2 capture capacity of up to 51.74 mu mol g-1. Furthermore, the effect of relative humidity on CO2 adsorption by biochar was investigated and exhibited promising stability under 2.7% relative humidity. However, the biochar activity for CO2 capture is reduced to 63.88% under 67.1% humidity after 50 cycles.

Automated summary

Direct air capture (DAC) of CO2 is considered a promising method for reducing carbon dioxide concentration and mitigating climate change. This study focused on using KOH-activated bamboo biochar as an adsorbent for DAC, which showed a high CO2 capture capacity and stability at low humidity. However, the biochar activity for CO2 capture decreased under high humidity conditions.