Table 2. Adsorption Equilibrium Isotherm Parameters for Tannin Adsorption onto OPT-Derived AC Obtained from Nonlinear Fitting and Reliability Indicators.

		Langmuir			Freundlich
adsorbate	pH	qmax (mg g–1)	KL (L mg–1)	Adj R2	n–1	Kf (mg g–1) (L mg–1)1/n	Adj R2
tannin	2	1047.47	0.0783	0.9953	0.7248	85.6352	0.9989
	4	1087.28	0.0082	0.9942	0.7762	14.2409	0.9855
	6	681.41	0.0293	0.9866	0.6106	34.1891	0.9563