Assessment of the Use of Epicarp and Mesocarp of Green Coconut for Removal of Fluoride Ions in Aqueous Solution

Table 2

Kinetics parameters for adsorption of fluoride ions by epicarp and mesocarp of green coconut.

Model	Epicarp			Mesocarp
Pseudo-first-order	25°C	35°C	45°C	25°C	35°C	45°C
(mg·g^−1)	0.1629	0.1742	0.1857	0.2358	0.2273	0.2323
(min^−1)	0.0107	0.0145	0.0194	0.0072	0.0111	0.0125
	0.9920	0.9850	0.9515	0.9952	0.9840	0.9821
	−174.2137	−164.7537	−145.9986	−171.3698	−153.7335	−151.5198
Pseudo-second-order
(mg·g^−1)	0.2070	0.2082	0.2120	0.3212	0.2309	0.2801
(g·mg^−1·min^−1)	0.0490	0.0758	0.1120	0.0187	0.0408	0.0512
	0.9876	0.9891	0.9761	0.9927	0.9927	0.9920
	−166.7448	−170.2651	−158.0703	−164.2642	−167.0878	−165.1528
Elovich model
(mg·g^−1·min^−1)	0.0054	0.0091	0.0149	0.0061	0.0092	0.0109
(g·mg^−1)	23.8895	24.8819	25.6593	17.1782	18.4377	18.2533
	0.9733	0.9650	0.9725	0.9591	0.9767	0.9800
	−153.7335	−150.3733	−155.6375	−135.0571	−147.3355	−149.5615
Intraparticle diffusion model
(mg·g^−1·min^−0.5)	0.0092	0.0089	0.0086	0.0131	0.0121	0.0121
(mg·g^−1)	−0.0043	0.0177	0.0379	−0.0222	0.0073	0.0172
	0.9396	0.9394	0.9419	0.9750	0.9697	0.9550
	−139.8852	−140.0723	−142.9349	−143.4189	−142.8754	−135.8247