A simple hydrothermal synthesis of zeolite X from bauxite tailings for highly efficient adsorbing CO2 at room temperature

Abstract

Abstract Zeolite X was successfully synthesized by a simple hydrothermal treatment from bauxite tailings, and the utilization rate of the bauxite tailings was reached 33.5%. The effects of the molar ratio of SiO2/Al2O3 (n(SiO2/Al2O3)), hydrothermal temperature and time on the preparation of zeolite X were systematically investigated. The CO2 adsorption capacity of the synthesized zeolite X samples were measured at room temperature over a pressure range of 0–101.325 KPa by a physical adsorption instrument. The results suggested that zeolite X, with a high crystallinity and regular octahedron morphology, was obtained at 110 °C for 16 h with the n(SiO2/Al2O3) fixed at 3.2. The N2 adsorption-desorption results showed that the produced zeolite X possessed a relatively high BET (Brunauer-Emmett-Teller) surface area of 571 m2/g with a 0.19 cm3/g micropore volume. The maximum CO2 adsorption capacity of zeolite X at 298 K was 6.4 mmol/g, which was 1.64-times that of the reported zeolite X synthesized from feldspar, indicating that the zeolite X can be synthesized from bauxite tailings and present excellent adsorption properties for greenhouse gases.