Table 1. Quantitative phosphorus-31 nuclear magnetic resonance results of kraft lignin (KL) and demethylated kraft lignin (DKL)

	Aliphatic hydroxyl group (mmol/g)	Aromatic hydroxyl group (mmol/g)	Carboxyl hydroxyl group (mmol/g)	Total (mmol/g)
KL	0.98	2.43	0.18	3.58
DKL	0.31	7.11	0.83	8.25