Table 2 Band assignments in FTIR spectra of biochar.

3400–3320

–OH stretching

Chen et al.²⁵; Hu et al.²⁴

3000–2800

Aliphatic CH stretching

Cui et al.²²

1630–1700

Aromatic carbonyl/carboxyl C=O/C=C stretching

Cimo et al.²⁷

1430–1420

Aromatic C=C stretching

Cui et al.⁹

1000–1157

C–O–C

Fan et al.¹³

840–880

Glucoside CH₂ deformation

Mia et al.²⁰

750–820

Aromatic rings

Li et al.²⁶