A Study of Silver Species on Silver-Exchanged ETS-10 and Mordenite by XRD, SEM and Solid-State ¹⁰⁹Ag, ²⁹Si and ²⁷Al NMR Spectroscopy

Abstract

Silver zeolites, especially Ag-ETS-10 and Ag-mordenite, actively bind xenon and iodine, two prime contaminants common to nuclear accidents. The evolution of silver species on silver exchanged ETS-10 (Ag/ETS-10) and mordenite (Ag/Mor) has been investigated by exposing the materials to a series of activation conditions in Ar, air and H2. The samples were characterized by XRD, SEM and solid-state 109Ag, 29Si and 27AI MAS NMR. The silver reduction and structural evolution have been illustrated by those techniques. The effectiveness of one sample of each type of sieve was tested for its ability to trap mercury from a gas stream. However, the results from this study demonstrate that the adsorption characteristics of silver-loaded sieves cannot necessarily be predicted using a full complement of structural characterization techniques, which highlights the importance of understanding the formation and nature of silver species on molecular sieves.

Transition metal-promoted hierarchical ETS-10 solid base for glycerol transesterification

“…48 Typically, there are two types of silicon chemical environments derived from ve different crystallographic Si sites, among which the Si [(OSi) 3 (OTi) 1 ] site especially exhibits four resonance peaks in the region of À94 to À97 ppm. [49][50][51] Obviously, compared with previous work, Ni/METS-10 gives rather different resonance pattern with only two peaks observed, indicating the discernible distortion of silicon sites and the presence of defects. This could be due to the incorporation of Ni species that are substituted for Si atoms at (3Si) sites and the introduction of hierarchical pores into ETS-10 framework.…”

Towards understanding of the mechanism of stepwise zeolite recrystallization into micro/mesoporous materials

“…MAS NMR spectra of the solids were recorded on a Bruker AVANCE II 400WB using a 4 mm MAS NMR probe. The 1 H, 13 C, 29 Si, 23 Na and 27 Al chemical shis are reported relative to TMS, Na(H 2 O) 6…”

“…1) shows an intense broad peak at ca. À112 ppm, corresponding to silicon atoms in Q 4 , Si(OSi) 4 positions of the mordenite framework 23,24 and two small peaks at ca. À106 and À103 ppm.…”

“…À106 and À103 ppm. The former indicates the presence of silicon atoms neighboring to Al (Q 4 , Si(OSi) 4 OAl), 23,24 while the latter corresponds to Q 3 , Si(OSi) 3 OH defects in the mordenite framework. The 29 Si CP MAS NMR spectrum of MOR conrms this assignment.…”

A Solvent Free Approach for the Preparation of Silver Modified Mesoporous Silica for Iodine Entrapment

“…3,4,5,6 Although not radioactive or inherently toxic these iodides can interact with other products during the drinking water treatment processes to create harmful by products. 7 The idea of a silver functionalized supports for iodine extraction is hardly new, 8,9,10 Ag-zeolites are typically used in nuclear industry, 1,11,12,13,14 whereas, as radiation is not a concern, in drinking water management Ag functionalized polymers can be used. 3,15,16 Here we expand on showed a silver content of 6.4% (weight %).…”