Simultaneous removals of cadmium(II) ions and reactive yellow 4 dye from aqueous solution by bone meal-derived apatite: kinetics, equilibrium and thermodynamic evaluations

Journal of Analytical Science and Technology

Table 2 Isotherm constants for the adsorption of Cd(II) ions and RY4 dye onto BMDA

Isotherms	Parameter	Cd(II)	RY4
Langmuir	Q_max (mg g⁻¹)	116.16	94.85
	b (L mg⁻¹)	0.167	0.035
	R_L	0.056	0.209
	R²	0.986	0.988
Freundlich	K_F × 10² ((mol g⁻¹) (mol L⁻¹)- ^1/n	36.15	16.32
	N	3.96	3.03
	R²	0.964	0.985
Tempkin	a_T (L mg⁻¹)	117.76	138.99
	b_T	2.25	0.604
	R²	0.975	0.987
Dubinin-Radushkevich	Q_s (mg g⁻¹)	103.43	65.95
	β × 10⁶ (mol J⁻¹)²	2.97	7.51
	E (kJ mol⁻¹)	410.30	258.03
	R²	0.998	0.971