Investigating Methylene Blue Removal from Aqueous Solution by Cysteine-Functionalized Mesoporous Silica

Table 4

Coefficient of pseudo-first-order and pseudo-second-order reactions for MB removal by MSNs-Cys at 150 ppm and 25°C.

	Parameters	pH
		1.5	7	8.5
Pseudo-first-order	qe, cal (mg/g)	6.59	6.27	2.78
	kl (min^−1)	0.0003	0.0148	0.0002
	R^2	0.94	0.83	0.75
Pseudo-second-order	qe, cal (mg/g)	80.64	86.95	140.84
	k2 (min^−1)	0.0004	0.0004	0.17
	R^2	1	0.93	0.99