Table 3.

Fitting parameters of adsorption isotherm models for the adsorption of Pb²⁺ and Cd²⁺ onto BSL-BC.

Isotherm model	Fitting parameter	Pb2+	Cd2+
Langmuir	Qm (mg g−1)	302.2	32.03
	K1 (L mg−1)	0.062	0.667
	R2	0.961	0.791
Freundlich	Kf (L g−1)	62.35	12.96
	1/n	0.272	0.192
	R2	0.900	0.968
Temkin	A (L g−1)	1.260	15.91
	b (J mol−1)	21.52	247.6
	R2	0.747	0.673
Dubinin–Radushkevich	Qm (mg g−1)	217.9	28.04
	K2 (mol2 J−2)	5.040 × 10–7	6.888 × 10–8
	E (kJ mol−1)	1.000	2.694
	R2	0.713	0.437

The solutions containing 1 g/L BSL-BC and initial concentrations of 10–700 mg/L Pb²⁺ (pH 5.0) or 10–200 mg/L Cd²⁺ (pH 5.5) were mixed for 8 h at 180 rpm and 25 °C.