Synthesis of mesoporous SiO₂ from rice husk for removal of organic dyes in aqueous solution

Abstract

Mesoporous SiO2 was prepared from rice husk for removal of methylene blue (MB) from aqueous solution. Asprepared SiO2 was characterized by FE-SEM, TEM, XRD, FT-IR and N2 adsorption/desorption isotherm. The effects of SiO2 dosage and contact time on adsorption of dye were investigated. The optimal dosage of SiO2 for removing methylene blue was 0.05 g and the removal efficiency of methylene blue reached to 91.9 % after 50 min of adsorption. The adsorption kinetic of methylene blue was studied to understand the mechanism of adsorption process. The kinetic data was analyzed by pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The results showed that rate of adsorption dye followed pseudo-second-model with a good regression correlation (R 2 = 0.999), the value of rate constant for adsorption process was calculated as 0.017 (g.mg -1 .min -1 ) and film diffusion was the rate limiting step. In addition, the cyclic test for as-prepared SiO2 was investigated and the removal efficiency was remained at 80.2% at 3 rd cyclic experiment.

Determination of Sudan I and II in Food by High-Performance Liquid Chromatography after Simultaneous Adsorption on Nanosilica

“…The adsorption capacities ( q e ) and removal efficiency ( R e ) of the nanosilica for the Sudan dyes were calculated using equations ( 1 ) and ( 2 ), respectively [ 23 ]: where C 0 , C t , and C e are the initial concentrations at time t and at equilibrium process (mg·L −1 ), respectively, V is the volume of the dye solution (L), and m is the mass of the adsorbent (g).…”

“…Further, nanosilica can be easily fabricated from rice husk and is a low-cost, ecofriendly, and abundant adsorbent [ 19 – 22 ]. Concerning its use as a sorbent, nanosilica has been mainly used to adsorb hydrophilic substances such as methylene blue [ 23 , 24 ] and Rhodamine B [ 25 ], whereas the adsorption of other organic dyes by other adsorbents has been studied intensely [ 26 – 31 ]. However, to date, the adsorption of hydrophobic organic dyes onto nanosilica has not been reported.…”

Utilización de cáscara de arroz como fuente de sílice para la síntesis de materiales mesoporosos y su aplicación en la degradación de diferentes compuestos orgánicos

“…En la Figura 1.a se muestra la isoterma de la muestra RHA-SiO 2 lavada con ácido nítrico. De acuerdo a la clasificación de la IUPAC (Everett et al 1971, Thi Thu et al 2019, este material presentó una isoterma del tipo IV, con un bucle de histéresis del tipo H1. La distribución del tamaño de poro de esta muestra está en el rango de 15-65 Å aproximadamente.…”

“…Éste último (Fig.3 (a)) presenta una morfología esférica. Luego, las imágenes de los materiales sintetizados (Fig.3 (c) y (d)) indican que las partículas no poseen una morfología particular, aunque se observan pequeñas partículas con forma esférica, las cuales se segregan formando aglomerados en un amplio rango de tamaños (Thi Thu et al 2019). A pesar de que estas muestras poseen una estructura mesoporosa altamente ordenada, las partículas no presentan una morfología bien definida y existe una agregación de partículas de tamaños irregulares.…”

Synthesis of Nano-Flakes Ag•ZnO•Activated Carbon Composite from Rice Husk as A Photocatalyst under Solar Light

“…The bulk density of RH is approximately 100-122 kg/m 3 , containing about 15-28 wt% of silica and 72-85 wt% of lignocellulose [21,22]. Therefore, to utilize RH properly, the studies to convert RH into silica or activated carbon have been widely performed [1,[23][24][25]. Then, the developed porous material has been attracted for the great attention of water purification technology.…”