Evaluation of eosin Y removal from aqueous solution using nano-mesoporous material MCFs: adsorption equilibrium, kinetics, and adsorption isotherms

Abstract

Mesocellular foams (MCFs) silica was successfully synthesized using hydrothermal method. The mesoporous material was characterized by X-ray diffraction, infrared spectroscopy, low temperature nitrogen adsorption–desorption, scanning electron microscopy, transmission electron microscopy. The low temperature nitrogen adsorption–desorption results showed that the synthesized MCFs has a diameter of 12 nm. Transmission electron microscopy revealed that the MCFs synthesized had a good honeycomb structure aperture and is conducive to the adsorption of dye macromolecule. This paper carried out the study on the adsorption of eosin Y by MCFs. The adsorption conditions of eosin Y by MCFs were optimized and the optimum adsorption conditions obtained were: MCFs:(eosin Y) = 250:1, pH 2.0, contact time 10 min at a room temperature of 22 ± 1 °C. Under the conditions, the adsorption effect was the best, the adsorption rate reached 97.95% and the adsorption capacity reached 3.96 mg/g. The research results of adsorption kinetics for the adsorption system displayed that the adsorption is the pseudo-second-order adsorption. The research results of adsorption thermodynamics showed that △G0 < 0, ΔH0 = − 40.08 kJ/mol, ΔS0 = − 51.11 J/(mol K), and the adsorption is an exothermic, spontaneous and entropy reduction reaction process. This adsorption conforms to the isothermal adsorption equation of Langmuir, belonging to a single molecular layer adsorption. All the linear correlation coefficients of the Langmuir isotherm equations fitting (R2) were greater than 0.999.