by Damien Yiyuan Khoo, Hussein Awala, Svetlana Mintova, Eng-Poh Ng
- •AlPO-5 molecular sieve is synthesized using new diol-substituted imidazolium template.
- •Effects of synthesis conditions on AlPO-5 crystallization are investigated.
- •AlPO-5 crystals with different morphologies and sizes are synthesized.
- •An efficient technique for template removal is presented.
AlPO-5 crystals are prepared using 3-(2,3-dihydroxypropyl)-1,2-dimethylimidazolium hydroxide, [dhpdm]OH, as a new structure-directing agent. The effects of synthesis conditions and precursor compositions on crystallinity, crystallite size, morphology and phase purity have been studied. The results showed that well-defined AlPO-5 crystals with various morphology and size were synthesized by careful tuning of the synthesis conditions. Furthermore, the state of the occluded [dhpdm]OH molecules in the AlPO-5 crystals was studied. The confined [dhpdm]OH molecules contain polar diol functionality, which provoked the very strong interaction with the AlPO-5 crystals. An alternative method for template removal based on the Fenton-like oxidation assisted reaction was used, which was demonstrated to be more efficient compared to conventional calcination.