Table 2. Composition Ratio, Basicity, and CO₂ Uptake Data of the Parent Chitosan and HTC Materials.

	H/C	O/C	N/C	basicity (mmol·g–1)	CO2 uptake (mmol·g–1)	ΔG° (kJ·mol–1)
CHIT	0.17	1.15	0.18	5.9	0.10	–6.43
CHIT-HTC-12	0.16	1.06	0.18	5.0	0.10	–2.41
CHIT-HTC-24	0.15	0.97	0.16	3.6	0.30	–3.63
CHIT-HTC-48	0.13	0.77	0.15	2.6	0.45	–3.15

	Langmuir			Freundlich
	KL (bar–1)	qm (mmol·g–1)	R2	KF (mmol1–(1/n)·g1/n·g–1)	n	R2
CHIT	13.4	0.13	0.994	0.12	3.6	0.880
CHIT-HTC-12	2.6	0.17	0.928	0.13	2.4	0.954
CHIT-HTC-24	4.3	0.40	0.974	0.34	3.1	0.980
CHIT-HTC-48	3.6	0.55	0.978	0.44	2.6	0.995

	pseudo-first order			pseudo-second order
	qe (mmol g–1)	k1 (min–1)	R2	qe (mmol·g–1)	k2 (g·mmol–1·min–1)	R2
CHIT	0.10	0.78	0.992	0.11	15.3	0.999
CHIT-HTC-12	0.16	0.76	0.991	0.14	6.8	0.996
CHIT-HTC-24	0.33	0.76	0.991	0.34	3.7	0.997
CHIT-HTC-48	0.44	0.77	0.992	0.47	3.2	0.999