Heavy Metal Ions Uptake by AlPO‐5 and SAPO‐5 Nanoparticles: An Experimental and Modeling Study

Synthesis of AlPO‐5 and SAPO‐5 nanoparticles was followed by applying hydrothermal method to use them as adsorbents in the removal of Fe 3+ , Pb 2+ , and Cd 2+ ions.The synthesized products were characterized using powder X‐ray diffraction, scanning electron microscope (SEM), FTIR and BET analysis. The adsorption isotherms and kinetics including Langmuir, Freundlich, pseudo‐first order, pseudo‐second order and intraparticle diffusion models have been employed. The experimental adsorption equilibrium and kinetic data nearly followed the Langmuir isotherm and pseudo‐second order kinetic model, respectively. It was found that the existence of the bridging hydroxyl group in the SAPO‐5 structure causes chemisorption of Fe 3+ , Pb 2+ , and Cd 2+ ions on SAPO‐5 which have greatly improved the performance of this adsorbent against its low external surface area. Using AlPO‐5 and SAPO‐5 as novel adsorbents in heavy metal adsorption for the first time indicated the great potential of these adsorbents in removal of heavy metal ions from water.