Properties
| Property | Why it matters | Typical science notes |
|---|
| Stable / aromatic C | Persistence & CDR | Fused aromatic rings increase with T and time; H/C_org and O/C_org track condensation |
| Porosity / surface area | Water, nutrients, microbes, sorption | Increases generally with higher pyrolysis T (then can decline at very high T) |
| pH / liming | Acid soils, Al toxicity | Many lignocellulosic biochars are alkaline |
| H/C_org | Persistence proxy; EBC/IBI quality | Upper limit 0.7 for “biochar”; lower ≈ more condensed |
| O/C_org | Persistence proxy (Spokas) | Often <0.4 required; lower ≈ longer expected half-life |
| CEC / ash / nutrients | Agronomy | Ash-rich chars supply minerals; CEC varies widely |
Quality thresholds (standards)
- EBC/IBI: H/C_org ≤ 0.7 (sometimes stricter for feed grades); O/C_org often ≤ 0.4
- Molecular transitions with charring temperature: Keiluweit et al. (2010), Environ. Sci. Technol. DOI: 10.1021/es9031419
- O/C as half-life predictor: Spokas (2010), Carbon Management DOI: 10.4155/cmt.10.32
Primary links