Influence of Synthesis Parameters on the Formation of SAPO-5 from Metakaolin

SAPO-5 molecular sieves was hydrothermally synthesized using metakaolin simultaneously as silica and aluminum sources, triethylamine as template agent, and phosphoric acid as phosphorous source. The influence of crystallization time, amount of triethylamine, hydrofluoric acid, and water on the structure and composition of crystalline phase were investigated. The structure and composition of product were analyzed by means of XRD, and BET. It was showed that the SAPO-5 molecular sieves with high crystallinity and well-defined morphology can be synthesized with a molar ratio of MK:P2O5:2.5TEA: 0.1HF:70H2O in the final reaction mixture at 200°C for 24h.