Separation of Spherical Nanosilica from Agricultural Wastes in Vietnam via Ultrasonic-Assisted Precipitation and Application for Effective Removal of Methylene Blue from Aqueous Solution

Table 2

Isotherm parameters calculated from the Langmuir and Freundlich models of MB adsorption onto BA-SiO₂, RHA-SiO₂, and pure-SiO₂.

Materials		BA-SiO2	RHA-SiO2	Pure-SiO2
Langmuir model	qm (mg·g^−1)	214.97	169.21	196.78
	KL	0.23	0.29	0.40
	R^2	0.821	0.868	0.882
Freundlich model	1/n	0.37	0.38	0.37
	KF	63.09	52.18	69.46
	R^2	0.933	0.984	0.969