Synthesis and characterization of Linde A zeolite coated with a layered double hydoxide

Linde type A zeolite (zeolite-LTA) coated with layered double hydroxide (LDH) was synthesized by a precipitation of LDH on zeolite-LTA and a hydrothermal treatment. When aqueous solutions containing magnesium chloride, and aluminum chloride were added dropwise to zeolite-LTA suspension at the constant pH of 10 using sodium hydroxide solution and then treated at hydrothermal conditions, LDH-coated zeolite-LTA was obtained. Scanning electron micrograph confirmed that the surface of zeolite-LTA was covered completely by fine LDH particles. The crystal structure of zeolite-LTA was retained even after the hydrothermal treatment and the coating with LDH particles, showing the possible application of the present multifunctional material for simultaneous uptake of harmful cations and anions, such as ammonium and phosphorous ions from wastewater.