Journal of Nanotechnology

Research Article

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

Parameters of Weber–Morris intraparticle diffusion study on MB adsorption of BA-SiO₂, RHA-SiO₂, and pure-SiO₂.


Materials	MB initial concentration (mg·L⁻¹)	The constant related to diffusion resistance (C)			The intraparticle diffusion rate constant (k_dif)
Materials	MB initial concentration (mg·L⁻¹)	First stage (C₁)	Second stage (C₂)	Third stage (C₃)	First stage (k_dif1)	Second stage (k_dif2)	Third stage (k_dif3)

BA-SiO₂	10	0.59	2.62		0.260	0.003
	20	0.63	4.37		0.490	0.025
	30	0.43	6.08		0.744	0.015
	40	1.40	8.56		0.886	0.002
	50	1.39	9.40		0.936	0.022

RHA-SiO₂	10	0.46	3.82		0.450	0.003
	20	0.37	6.53		0.793	0.002
	30	−1.31	3.52	8.77	1.295	0.590	0.012
	40	0.66	7.30	11.50	1.513	0.470	0.015
	50	−0.43	7.19	13.13	1.868	0.681	0.020

Pure-SiO₂	10	0.42	3.91		0.510	10⁻⁵
	20	0.13	7.10		0.884	0.001
	30	−1.28	9.26		1.435	0.045
	40	−2.34	5.42	13.27	2.182	0.975	0.001
	50	−1.28	10.88	14.09	2.192	0.391	0.064