Preparation and characterisation of activated carbon from Vitisvinifera leaf litter and its adsorption performance for aqueous phenanthrene

Applied Biological Chemistry

Table 4 Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm constants for the adsorption of phenanthrene onto activated carbons obtained from V. vinifera

Isotherm models	Parameters	ZAac	ZBac	PAac
Langmuir	R²	0.99	0.95	0.98
	q_m (mg/g)	94.12	60.07	89.13
	K_L (L/mg)	0.48	0.19	0.39
	R_L	0.94	0.98	0.83
Freundlich	R²	0.99	0.97	0.99
	K_f	1.27	1.18	1.16
	1/n	0.75	0.66	0.68
	n	1.33	1.52	1.47
Temkin	R²	0.94	0.95	0.92
	K_T (L/mg)	0.28	0.26	0.38
	b_T (kJ/mol)	4.03	4.40	3.34
Dubinin–Radushkevich	R²	0.94	0.92	0.98
	qDRB	2.80	1.13	1.06
	K_ad (mol²/kJ²)	3.00 × 10⁻⁸	9.00 × 10⁻⁹	4.0 × 10⁻⁹
	E (kJ/mol)	4.08	7.45	11.18

ZAac: activated with ZnCl₂ at 5:2 biomass to ZnCl₂ ratio, ZBac: activated with ZnCl₂ at 5:1 biomass to ZnCl₂ ratio, PAac: activated with H₃PO₄ at 5:2 biomass to H₃PO₄ ratio