The Removal of Chromium(VI) from Aqueous Solution by Amine-Functionalized Zeolite: Kinetics, Thermodynamics, and Equilibrium Study

Abstract

In this study, the removal of Cr(VI) from aqueous solution by modified zeolite with 3-aminopropyltriethoxysilane was investigated. The effect of various parameters such as pH, contact time, temperature, initial concentration of Cr(VI) ion, common cations, and anions on the adsorption of Cr(VI) was studied. The modified zeolite was characterized by following instrumental analysis of XRD, SEM/EDS, BET, and FT-IR. Based on calculated thermodynamic parameters values (∆G 0 < 0, ∆H 0 > 0, and ∆S 0 > 0) and kinetic properties of the adsorption of Cr(VI) by modified zeolite, it was concluded that the ratelimiting step of the process is a second-order chemical reaction. The results of the adsorption isotherm study confirmed that the adsorption follows the Langmuir isotherm model. The maximum adsorption capacity was 13.5 mg/g.

Kinetic, Isotherm, and Equilibrium Investigation of Cr(VI) Ion Adsorption on Amine-Functionalized Porous Silica Beads

“…In addition, the Cr(VI) ion adsorption capacity of the NH-silica beads obtained in this study was compared with those of various particles functionalized by silane coupling reactions in Table 9 [ 8 , 11 , 12 , 13 , 46 , 47 , 48 , 49 , 50 , 51 ]. First, we should bear in mind that the experimental conditions, such as the initial pH value, temperature, dose of the adsorbent sample, and initial concentration and volume of the aqueous K 2 Cr 2 O 7 solution, vary from article to article.…”

Efficient adsorption of cesium cations and chromate anions by one-step process using surfactant-modified zeolite

“…The spectrum of CTAB-zeolite, in contrast to natural zeolite, exhibits new absorption peaks located at 2919, 2853, and 1481 cm −1 . The first and the second peaks correspond to the C-H asymmetric and symmetric stretching vibration modes of the methylene group of the surfactant (Nasanjargal et al 2021). These two peaks together with that at 1481 cm −1 , due to the C-N stretching vibrations of the quaternary ammonium group of the surfactant, testify that the natural zeolite's surface is successfully covered by cetyltrimethylammonium bromide surfactant.…”

“…It can be noticed that both of the compared materials exhibited absorption peaks at 3628, 3425, 1642, 1032, 789, and 468 cm −1 . The peak at 3628 cm −1 corresponds to the stretching vibration of Si-OH, whereas the broad band centered at 3425 cm −1 and that at 1642 cm −1 are corresponding to water molecules associated with exchangeable cations in zeolite structure (Nasanjargal et al 2021;Wang et al 2018). The peak at 1032 cm −1 is assigned to the asymmetric stretching vibrations of M-O bonds (M = Si and Al) in MO 4 tetrahedral (Nasanjargal et al 2021).…”

“…The peak at 3628 cm −1 corresponds to the stretching vibration of Si-OH, whereas the broad band centered at 3425 cm −1 and that at 1642 cm −1 are corresponding to water molecules associated with exchangeable cations in zeolite structure (Nasanjargal et al 2021;Wang et al 2018). The peak at 1032 cm −1 is assigned to the asymmetric stretching vibrations of M-O bonds (M = Si and Al) in MO 4 tetrahedral (Nasanjargal et al 2021). The peaks at 789 and 468 cm −1 are ascribed to the stretching vibrations of M-O groups and the bending vibrations of O-M-O groups, respectively (Hommaid and Hamdo 2014).…”

“…This arrangement resulted in the formation of a positively charged surface as the polar groups of the surfactant, which carry a positive charge, are directed to the liquid phase. Therefore, cationic surfactant-modified zeolites are known for their ability to adsorb anionic contaminants from aqueous solutions via anion exchange with the counter ion of the surfactant (Nasanjargal et al 2021;Szala et al 2015;Hommaid and Hamdo 2014;Swarnkar and Radha 2011;Zeng et al 2010;Warchol et al 2006;Ghiaci et al 2004;Haggerty and Bowman 1994). In reviewing these previous publications, it is found that the researchers are mainly concerned with the adsorption of anionic contaminants only and few studies are reported on simultaneous adsorption of cationic and anionic species.…”