Combination of natural silica and alumina sources for synthesis of MCM-22 zeolite

Worapak Tanwongwan; Nuwong Chollacoop; Kajornsak Faungnawakij; Suttichai Assabumrungrat; Puritut Nakhanivej; Apiluck Eiad-Ua

doi:10.1016/j.heliyon.2023.e18772

Combination of natural silica and alumina sources for synthesis of MCM-22 zeolite

Heliyon. 2023 Jul 28;9(8):e18772. doi: 10.1016/j.heliyon.2023.e18772. eCollection 2023 Aug.

Authors

Worapak Tanwongwan¹, Nuwong Chollacoop², Kajornsak Faungnawakij³, Suttichai Assabumrungrat⁴, Puritut Nakhanivej⁵, Apiluck Eiad-Ua¹

Affiliations

¹ College of Materials Innovation and Technology, King Mongkut's Institute of Technology Ladkrabang (KMITL), Chalongkrung Rd., Ladkrabang, Bangkok, 10520, Thailand.
² National Energy Technology Center (ENTEC), National Science and Technology Development Agency (NSTDA), Phahonyothin Rd. Khlong Luang, Pathum Thani, 12120, Thailand.
³ National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Phahonyothin Rd. Khlong Luang, Pathum Thani, 12120, Thailand.
⁴ Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Rd., Phatumwan, Bangkok, 10330, Thailand.
⁵ Warwick Manufacturing Group (WMG), University of Warwick, Coventry, CV4 7AL, United Kingdom.

Abstract

Zeolite has become a promising material that can potentially play a pivotal role in resolving environmental crises. Among zeolite families, MCM-22 zeolite shows outstanding intrinsic properties associated with the topology and porous structure, offering ion-exchange advantages for catalytic activity processes. The synthesis of MCM-22 zeolite becomes challenging when concerning the cost and catalytic performance. To overcome this bottleneck, we demonstrate a sustainable route of a hydrothermal process using natural resources as starting materials. Rice husk from agricultural waste was used as a silica source while natural clays (kaolin and bentonite) were applied as alumina sources. The products from natural sources were compared with the use of commercial starting materials, e.g., NaAlO₂ (for alumina) and Na₂SiO₃ and TEOS (for silica), in points of crystal, compositional, and morphological views. We showed that the high purity of MCM-22 zeolite can be obtained from rice husk silica (RHS) and aluminosilicate gel (ASG) extracted from kaolin, while the use of ASG extracted from bentonite tended to be unsuitable to generate the zeolite formation. We also studied the effects of reaction time and the ratio of RHS/ASG on the crystallinity and surface area of MCM-22. The architecture and acidity of an optimal product were explored by Nuclear magnetic resonance spectroscopy and Temperature-programmed desorption of ammonia, demonstrating the success of achieving well acidity.

Keywords: Hydrothermal; MCM-22; Natural clays; Rice husk silica; Zeolite.