The crystal structures of zeolite Y Ni2+ exchanged at pH 4.9, fully dehydrated (|Ni29.7(Ni4AlO4)1.1H12.3|[Si117Al75O384]-FAU) and partially dehydrated (|Ni14.1(NiOH2)16.4(Ni4AlO4)1.1(H3O)9.6|[Si117Al75O384]-FAU), were determined by single-crystal synchrotron X-ray diffraction techniques. They were refined to the final error indices R1/wR2 = 0.044/0.115 and 0.052/0.153, respectively, in the cubic space group Fd-3m. Some dealumination of the zeolite framework occurred during Ni2+ exchange. In the fully dehydrated structure, Ni2+ ions primarily occupy sites I and II, with additional Ni2+ ions at site I', site II', and a second site II. In the partially dehydrated structure, Ni2+ occupies six different sites: I, I', a second site I', II, a second site II, and III'. Because of the low pH of the Ni2+ exchange solution, some H3O+ ions are observed in partially dehydrated Ni2+-Y; correspondingly some H+ ions are required for charge balance in fully dehydrated Ni2+-Y. The nonframework oxygen atoms in water and orthoaluminate coordinate to some of the Ni2+ ions. Upon full dehydration, a substantial Ni2+ migration from I' sites to site I is seen. Unlike the situation at pH 6.2, no hydrolyzed Ni2+ ions (NiOH+, Ni2OH3+, Ni4(OH)44+) appear to have exchanged into the zeolite.

Preparation and single-crystals of fully and partially dehydrated zeolite Y (FAU, Si/Al = 1.56) Ni<sup>2+</sup> exchanged at a low pH 4.9

245th National Meeting (2013)

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Preparation and single-crystals of fully and partially dehydrated zeolite Y (FAU, Si/Al = 1.56) Ni2+ exchanged at a low pH 4.9

Preparation and single-crystals of fully and partially dehydrated zeolite Y (FAU, Si/Al = 1.56) Ni²⁺ exchanged at a low pH 4.9