One-, Two-, and Three-Parameter Isotherms, Kinetics, and Thermodynamic Evaluation of Co(II) Removal from Aqueous Solution Using Dead Neem Leaves

Table 4

Kinetic parameters for Co(II) adsorption on DNL.

Models	Parameters	10 mg/L	100 mg/L	500 mg/L
Pseudofirst-order	k1 (min)	−0.031	0.0004	0.028
	qe, c (mg/g)	0.052	1.112	2.167
	qe, ex (mg/g)	8.541	90.452	487.086
	R^2	0.8281	0.0006	0.7971
Pseudosecond-order	k2 (g/mg/min)	0.269	0.139	0.055
	qe, c (mg/g)	8.157	89.286	476.190
	qe, ex (mg/g)	8.541	90.452	487.086
	R^2	0.9998	1.000	1.000
Intraparticle diffusion (Weber–Morris)	kid (mg/g/min^1/2)	0.051	0.046	0.353
	C (mg/g)	8.646	89.158	484.33
	R^2	0.6472	0.0227	0.9754

q_e, c and q_e, ex are, respectively, calculated and experimental equilibrium amounts adsorbed.