Seawater Reinforces Synthesis of Mesoporous and Microporous Zeolites from Egyptian Fly Ash for Removal Ions of Cadmium, Iron, Nickel, and Lead from Artificially Contaminated Water

Abstract

This study focuses on the production of mesoporous and microporous zeolites via fusion pre-treating fly ash with NaOH followed by hydrothermal treatment utilizing seawater. Three pretreatments for fly ash were carried out utilizing 1:1, 1.2:1, and 1.4:1 of NaOH:fly ash ratio to compare the removal efficiency for cadmium Cd(II), iron Fe(II), nickel Ni(II), and lead Pb(II) from artificially contaminated water. The impacts of several variables including concentrations, weights, pH, and contact times were examined to acquire knowledge on the adsorption rate. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Brunaauer-Emmett-Teller (BET) were utilized to investigate zeolite structures. N2 adsorption/desorption isotherms demonstrated that the synthetic zeolites were mesoporous and microporous materials with a higher specific area (347, 240, and 127 m2/g) than the values for raw fly ash (15m2/g). The X-ray diffraction outcome suggested that the synthetic products mainly belonged to phillipsite, carbonate cancrinite, and hydroxysodalite. These outcomes showed that fly ash and seawater from power plants are appropriate for synthesizing high-quality zeolites. For contaminated water treatment, the products are effective for removal Cd(II), Fe(II), Ni(II), and Pb(II) at pH 7, contact time 45 min, and dose 1 g/L. Zeolites recycling outcomes showed that the removal efficiency of investigated metal ions by Z1, Z2, and Z3 was reduced by an average of 7%, 5%, and 3% after regeneration.