Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave-Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni²⁺ Ions from Aqueous Solution

Table 5

Comparison of the correlation coefficients of kinetic parameters for the adsorption of Ni²⁺ ions onto ZLRC.

Models	Parameters
	𝑘1 (min^−1)	0.0253
Pseudo-first-order model	𝑞𝑒 (mg/g)	181.130
	𝑅^2	0.821
	𝑘2 (g/mg/min)	0.0207
Pseudo-second-order model	𝑞𝑒 (mg/g)	250.0
	ℎ	5.1800
	𝑅^2	0.9020
	𝑘dif (mg/(g·min^1/2))	17.11
Intra-particle diffusion model	𝐶	5.2520
	𝑅^2	0.960
	𝐴𝐸 (mg (g/min))	0.0217
Elovich model	𝑏 (g/mg)	4.0768
	𝑅^2	0.8750