A simple method for determining biochar condensation

The output
In the absence of ring currents, 13 C-benzene gives a peak at 128.7 ppm.
Ring currents shift that peak to lower values when sorbed to biochar
Expressed as Δδ – i.e. the difference from 128.7 ppm
Wood 250
Δδ ‐0.3
Wood 450
Δδ ‐1.5
Wood 850
Δδ ‐8.1
Grass 250
Δδ ‐0.1
Grass 450
Δδ ‐1.1
Grass 850
Δδ ‐6.5
Lab-produced
biochars – long
heating times (~2h)
Clear effect of
production
temperature – more
negative Δδ values
for higher temps
(more condensed)
Smaller effect of
starting material –
wood biochars more
condensed than
grass biochars
Δδ ‐0.7
Δδ ‐1.5
Δδ ‐1.6
Δδ ‐0.5
Δδ ‐0.3
Δδ ‐3.8
Cow manure
500°C
Green waste
500°C
Green waste
600°C
Papermill waste
500°C
Poultry litter
500°C
Rice husks
???°C
Fast pyrolysis
biochars –
shorter heating
times
Generally less
negative Δδ values
for given temps
High ash biochars
have lower
condensation
Rice husk char
(production temp
unknown)
substantially more
condensed