Effect of indoor contamination on carbon dioxide adsorption of wood-based biochar – Lessons for direct air capture

Mixed wood sawdust is a common waste material in many parts of the world. This study characterized biochar that was produced from locally available mixed wood sawdust with respect to its capability to perform Direct Air Capture of ambient carbon dioxide. Specifically, the impact that pyrolysis temperature, heating rate and ambience carbon dioxide concentration have on the carbon capture and sequestration capability of this biochar is evaluated. In addition, the reduction in this capability due to contamination by indoor particulate matter was studied. Results showed that pyrolysis temperature is the only significant factor that determines the carbon capture and sequestration capability of the biochar produced. Furthermore, by exposing biochar samples to an indoor environment containing particulate matter with a minimum size of 0.35 μm, carbon capture and sequestration capability of the biochar was shown to be reduced by about 8.33 times, under an ambient environment of 600 ppm of carbon dioxide. These findings hold important lessons on how biochar can be deployed for Direct Air Capture in the field, and as a mean for enhancing indoor air quality in buildings.