Meyer Zu Drewer et al. (2026): Combining biochar and basanite rock powder enhances carbon dioxide removal by carbonate alkalinity production

Johannes Meyer Zu Drewer, Maria-Elena Vorrath, Thorben Amann, Jens Hartmann, Maria Ansari, Marcela Cárcamo Pérez and Nikolas Hagemann, IN: Frontiers in Climate, https://doi.org/10.3389/fclim.2026.1853116

The combination of enhanced rock weathering (ERW) with pyrogenic carbon capture and storage (PyCCS) has been proposed to harness synergistic effects on carbon dioxide removal (CDR). This can be facilitated by co-application of silicate rock powder and biochar or co-pyrolysis of rock powder and biomass to produce rock-enhanced (RE-)biochar. While it is well documented that co-pyrolysis of biomass and silicate rock does not affect the carbon yield nor the aromaticity of RE-biochar, the effect of co-pyrolysis and co-application on alkalinity production by ERW remains poorly constrained. Here, the authors quantified the daily and cumulative production of carbonate alkalinity (TAcarb g⁻¹ basanite) in a controlled weathering experiment conducted in columns. They compared 14 treatments consisting of basanite rock powder, biochar, co-applications or RE-biochars produced at contrasting highest treatment temperatures (HTT) of 450 °C and 750 °C. The experiment was conducted under two conditions: with sandy, agricultural topsoil under ambient pCO₂ and with washed, quasi non-reactive quartz sand under elevated pCO₂ the latter designed to better isolate leachate signals originating from the amendments alone.

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