Application of nanosilica-based adsorbent for the removal of rhodamine B and methylene blue from aqueous solutions

Abstract

a b s t r a c tIn this study, an adsorbent based on nanosilica molecules was synthesized by chemical activation and changing the structure of a sodium silicate )Na 2 SiO 3 (. The adsorbent was characterized by scanning electron microscope/energy-dispersive X-ray spectroscope, X-ray diffraction analysis, transmission electron microscope, and Brunauer-Emmett-Teller analysis for morphologic properties and determination of specific surface area. Sorption experiments were carried out to evaluate the effects of variables, such as initial dye concentration, contact time, and pH on the dye removal. Different isotherm and kinetic models were used to evaluate the sorption equilibrium and describe the sorption process. More than 75% removal efficiency was obtained within 15 min at adsorbent dose of 10 g/L for initial dye concentration of 150 mg/L. The maximum sorption capacity was found to be 92.9 mg/g at pH 10 and 70.9 mg/g at pH 9 for RB and MB, respectively. The best fit was achieved by the Langmuir isotherm equation (R 2 values = 0.99 and 0.98) for RB and MB, respectively. The kinetic studies showed that the RB and MB dye sorption onto the nanoadsorbent was best described by the pseudo-second-order kinetic model. This study showed that the sodium silicate nanoadsorbent can be an ideal adsorbent for dye removal and may also be used in environmental research in other fields.

Novel Hybrid Adsorption-Electrodialysis (AdED) System for Removal of Boron from Geothermal Brine

“…Boron uptake of the adsorbent in the first minute was found as 66.2%; therefore, the fast kinetic nature of the adsorbent was observed. Linearized forms of the pseudo-first-order kinetic model (eq ) and the pseudo-second-order kinetic model (eq ) were applied to experimental data Log ( q e − q t ) = log ( q e ) − k 1 t 2.303 t q normale = 1 k 2 q normale 2 + t q normale where q e (mg/g) is the boron adsorbed in equilibrium and q t (mg/g) is the boron adsorbed at a certain time, while t is time (min –1 ) with k the rate constants for the models.…”

“…Linearized forms of the pseudo-first-order kinetic model ( eq 4 ) and the pseudo-second-order kinetic model ( eq 5 ) were applied to experimental data. 31 where q e (mg/g) is the boron adsorbed in equilibrium and q t (mg/g) is the boron adsorbed at a certain time, while t is time (min –1 ) with k the rate constants for the models. The results of the pseudo-first-order model and the pseudo-second-order model were given in Figure 4 b and Figure 4 c, respectively.…”

“…Linearized forms of the pseudo-first-order kinetic model (eq 4) and the pseudo-second-order kinetic model (eq 5) were applied to experimental data. 31 = q q q k t Log( ) log( ) 2.303…”

Removal of acetaminophen (ACT) from aqueous solution by using nanosilica adsorbent: experimental study, kinetic and isotherm modeling

“…The nanosilica-based adsorbent is a novel alternative and eco-friendly method widely accepted for efficient adsorption of organic compounds such as PPCPs (Ali et al , 2016; Shanker et al , 2017). Nanosilica-based adsorbent has given considerable attention between these materials due to its features such as scavenger of for adsorptive removal of pollutants compared to other synthesis adsorbents (Eslami et al , 2018). Owing to a large number of pores in the nanosilica-based adsorbent, it can adsorb pollutants through its stacking interaction.…”

“…The precipitated SiO 2 was separated and washed with distilled water. The precipitated SiO 2 was dried in a cyclone dryer based on Eslami et al (2018) method. The formation of nanosilica-based adsorbent placed in polyethylene for further characterization using XRD, SEM and BET analysis.…”