Efficient removal of cadmium(II) with SBA-15 nanoporous silica: studies on equilibrium, isotherm, kinetics and thermodynamics

Abstract

Nanomesoporous silica SBA-15 was prepared by hydrothermal method. The samples were characterized by powder X-ray diffraction and scanning electron microscopy. The fibrous particles with a diameter of 333 ± 10 nm were obtained. Nanoporous mesoporous SBA-15 was used as an adsorbent to adsorb Cd 2+ in water body. The effects of conditions such as acidity were studied, and the optimized adsorption conditions were obtained. The results showed that when the pH value was 5.0, the temperature was 25 ± 1 °C and the adsorption time was 40 min, the nanomesoporous SBA-15 had the best adsorption effect for Cd 2+ and the adsorption rate was reached 73.28% and the adsorption capacity was 9.84 mg/g. Study found that the adsorption is the quasi-second-order kinetic model, which belongs to the Freundlich adsorption type. The results of adsorption thermodynamics showed that when the temperature is 25-55 °C, the adsorption is spontaneous exothermic reaction, ∆G 0 < 0, the adsorption enthalpy change ΔH 0 = − 54.732 kJ/mol, the adsorption entropy change ∆S 0 = − 129.343 J/(mol K). The effects of nitric acid and hydrochloric acid on desorption were investigated, respectively. The results showed that the desorption effect of 0.1 mol/L nitric acid as desorbent was better than that of hydrochloric acid. At desorption for 10 h, the desorption rate was the highest, reaching 65.56%.

Enthalpies of Immersion in Caffeine and Glyphosate Aqueous Solutions of SBA-15 and Amino-Functionalized SBA-15

“… 9 − 12 In this sense, production optimization and lower cost techniques have been explored, including use of alternative silicon sources such as rice husk 13 , 14 or coal fly ash 15 and washing methods with environmentally friendly solvents to remove the template. 12 Additionally, the ability of SBA-15 to host a large series of functional groups by methods of cocondensation, isomorphic replacement, or grafting leads it to be a promising porous solid 10 that opens a tremendously valuable possibility of developing solids with very specific characteristics, for industrial applications related to adsorption processes 16 , 17 and membrane separation, 18 , 19 in pharmaceutical applications like drug delivery, 20 , 21 biosensing, 22 , 23 and for catalysis. 24 , 25 …”

Physicochemical Characterization of Santa Barbara Amorphous-15 (SBA-15) and Its Functionalization with Polyaniline for Phenol Adsorption

“…SBA-15 material (Santa Barbara Amorphous No 15) is a mesoporous silica that has been increasing in importance due to its textural properties, regular mesoporous structure, high specific surface area, thermal and mechanical stability, distribution, and pore size. Its high uniformity allows for its potential use in the removal of inorganic and organic contaminants in aqueous solutions [34]. The functionalization of the silica generates an increase in the adsorption capacity because, upon including functional groups, the active sites increase and the conditions on the chemical surface improve [29].…”

Sorption of Ce(III) by Silica SBA-15 and Titanosilicate ETS-10 from Aqueous Solution

“…However, high reagents and energy consumption, low selectivity, generation of secondary pollution, and by-products are serious limitations of the mentioned techniques [3,6]. Physical adsorption has great prospects owing to its effectiveness, environmental safety, and feasible operation [7]. The key role in the adsorption process belongs to the adsorbent.…”

“…Mesoporous material is a class of materials with high specific surface area, low relative density, high porosity, continuously adjustable pore size in a certain range, and good hydrothermal stability, which can be applied for metal removal from wastewater [7]. ETS-10 is a microporous titanosilicate which, by contrast with zeolites, consists of SiO 4 tetrahedra, TiO 6 octahedra bridged by oxygen atoms, and exchangeable charge-balancing cations (K and Na) [8,9].…”

“…SBA-15 is one of the most promising silica mesophases due to its large surface area, narrow pore size distribution, high hydrothermal, and mechanical stability [11]. The maximum adsorption capacity of Na-mesoporous silica SBA-15 toward cadmium was 9.84 mg/g [7]. N-Propylsalicylaldimino-functionalized SBA-15 mesoporous silica was applied for Cu 2+ , Co 2+ , Ni 2+ , and Zn 2+ sorption [12].…”