Insights into the ion-exchange properties of Zn(ii)-incorporated MOR zeolites for the capture of multivalent cations. Issue 7 (4th February 2019)

• Record Type: Journal Article
• Authors: Wang, Bangda; Koike, Natsume; Iyoki, Kenta; Chaikittisilp, Watcharop; Wang, Yi; Wakihara, Toru; Okubo, Tatsuya
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 7(2019)
• Page Start: 4015
• Page End: 4021
• Publication Date: 2019-02-04
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp06975a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The ion exchange property of MOR zeolites for multivalent cations is improved in the presence of Zn(ii ). Abstract : Understanding the properties of zeolites for cation exchange is important because the ion-exchange performance largely determines their suitability in applications such as catalysis and adsorptive separation. We synthesized a Zn(ii )-incorporated mordenite-framework aluminosilicate zeolite (Zn, Al-MOR), in which both Zn and Al are substituted in the framework, and studied its ion-exchange behavior for multivalent cations. For comparison, the original aluminosilicate mordenite (Al-MOR) was also synthesized with a composition adjusted to ensure that its charge density was similar to that of Zn, Al-MOR. While the incorporation of Zn(ii ) led to a slower kinetic process, the selectivities and the exchange capacities toward multivalent cations (especially divalent cations) were significantly improved. Herein, we discussed the mechanism responsible for improving the ion-exchange performance in the presence of Zn(ii ) and found that the incorporation of Zn(ii ) led to a significant improvement in the ion-exchange temperature dependence of the MOR, which led to the ability to enhance ion-exchange capacity through temperature control during actual application. It was also revealed that the presence of Zn(ii ) significantly improves selectivity and spontaneity toward the exchange of multivalent cations, Ni 2+ . Moreover, XRD and nitrogen-adsorption/desorption analyses revealed that the structures of the materials are maintained during the ion exchange, which is indicative of superior structural stability and tolerance to ion exchange.