Table 1.

R² and constant values for the different adsorption kinetics models of Ni(II). (Adsorption experiments—sample dosage: 0.05 g; initial Ni(II) concentration: 700 mg/L; pH value: 5.5; temperature: 50 °C; adsorption time: 40 min).

Metal	Parameters	Pseudo-First-Order		Pseudo-Second-Order		Intraparticle Diffusion		Elovich Model
Ni(II)	R2	0.9883		0.9991		0.6781		0.7025
	Constants	k1	0.0059 min−1	k2	0.0779 min−1	ki	9.274 mg/(g min0.5)	α	22.51 mg/(g min)
		qe	943.02 mg/g	qe	1109.84 mg/g			β	0.0097 g/mg