Evaluation of an Adsorbent Based on Agricultural Waste (Corn Cobs) for Removal of Tyrosine and Phenylalanine from Aqueous Solutions

Table 1

Kinetic parameters for Tyr adsorption.

	Tyr initial concentration (mg L^−1)
	20	30	50	75	100
	25°C
𝑞𝑒 (experimental)	2.01	2.74	4.63	7.31	9.11
Pseudofirst-order
𝑘1 (h^−1)	6.212	3.754	1.735	1.772	1.786
𝑞𝑒 (estimated) (mg g^−1)	1.76	2.52	4.52	7.20	9.02
𝑟^2	0.881	0.897	0.912	0.955	0.955
RMS (%)	16.004	7.201	9.638	8.304	8.375
Pseudosecond-order
𝑘2 (g mg^−1 h^−1)	4.616	2.126	0.508	0.307	0.245
𝑞𝑒 (estimated) (mg g^−1)	1.92	2.72	4.94	7.93	9.95
𝑟^2	0.953	0.961	0.943	0.973	0.967
RMS (%)	3.990	4.410	7.511	5.881	6.449
	35°C
𝑞𝑒 (experimental)	2.16	2.77	4.80	6.79	8.20
Pseudofirst-order
𝑘1 (h^−1)	2.991	6.415	4.020	11.674	4.182
𝑞𝑒 (estimated) (mg g^−1)	2.06	2.51	4.55	6.14	7.87
𝑟^2	0.984	0.955	0.972	0.942	0.982
RMS (%)	7.705	3.573	3.111	3.543	3.377
Pseudosecond-order
𝑘2 (g mg^−1 h^−1)	1.791	3.375	1.068	2.601	0.720
𝑞𝑒 (estimated) (mg g^−1)	2.26	2.72	4.50	6.60	8.52
𝑟^2	0.993	0.986	0.982	0.983	0.999
RMS (%)	1.607	1.783	4.898	1.988	0.362
	45°C
𝑞𝑒 (experimental)	1.95	2.62	4.55	6.44	8.12
Pseudofirst-order
𝑘1 (h^−1)	3.831	5.204	3.701	6.713	4.456
𝑞𝑒 (estimated) (mg g^−1)	1.80	2.53	4.555	5.94	7.59
𝑟^2	0.970	0.991	0.964	0.940	0.921
RMS (%)	9.728	1.790	7.532	4.478	5.749
Pseudosecond-order
𝑘2 (g mg^−1 h^−1)	2.588	2.811	2.492	1.581	0.867
𝑞𝑒 (estimated) (mg g^−1)	1.98	2.73	4.62	6.40	8.15
𝑟^2	0.990	0.997	0.993	0.987	0.974
RMS (%)	2.569	1.345	1.588	2.147	2.994