Synthesis of hydroxyapatite/polyethylene glycol 6000 composites by novel dissolution/precipitation method: optimization of the adsorption process using a factorial design: DFT and molecular dynamic

Table 5 Parameters obtained by the kinetic models for the composite HAp and HAp-PEG 6000

Pseudo-First-Order Kinetic Model
	HAp			HAp-PEG 6000
	K₁ (g/mg.min)	Q_cal (mg/g)	R²	K₁ (g/mg.min)	Q_cal (mg/g)	R²
Pb⁺²	0.246	90.260	0.913	0.253	100.836	0.968

The pseudo-second-order parameters for uptaking of Pb²⁺ ions HAp and HAp-PEG 6000
	HAp			HAp-PEG 6000
	K₂ (g/mg.min)	Q_cal (mg/g)	R²	K₂ (g/mg.min)	Q_cal (mg/g)	R²
Pb⁺²	1.005	3.663	0.981	0.272	3.945	0.979

Intra-particle diffusion parameters of Pb²⁺ ions(Fig. S5c) bonding onto HAp and HAp-PEG 6000
T (K)	HAp			HAp-PEG 6000
	K_id	Z	R²	K_id	Z	R²
Pb⁺²	23.1	10.618	0.934	27.269	7.431	0.951

Thermodynamics parameters values for the adsorption of Pb⁺² ions onto HAp and HAp-PEG 6000
T(K)	HAp			HAp-PEG 6000
	∆G° (KJ/mol)	∆H° (KJ/mol)	∆S° (J/K.mol)	∆G° (KJ/mol)	∆H° (KJ/mol)	∆S° (J/K.mol)
298	− 23.077	16.268	77.494	− 19.528	12.349	65.574
313	− 24.239			− 20.512
323	− 25.015			− 21.168
Liquid film diffusion model
	K_df	R²
HAp	2.094	0.918
HAp-PEG 6000	2.218	0.942

ISSN: 2661-801X