期刊
ACS APPLIED NANO MATERIALS
卷 -, 期 -, 页码 -出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsanm.2c01741
关键词
iodine capture; xerogels; silver-based sorbents; X-ray absorption spectroscopy; X-ray photoelectron spectroscopy; thiolation
资金
- Department of Energy (DOE) [DE-AC05-76RL01830]
- Department of EnergyOffice of Nuclear Energy
- Office of Biological and Environmental Research at PNNL
- DOE Office of Science [DE-AC02-06CH11357]
- Division of Chemistry (CHE), National Science Foundation [NSF/CHE-1834750]
- Division of Materials Research (DMR), National Science Foundation [NSF/CHE-1834750]
- DOE Office of Science through the National Virtual Biotechnology Laboratory
- Coronavirus CARES Act
This study investigated thiolated and unthiolated Ag-Al-Si-O xerogels for iodine gas capture, with thiolated Ag0-xerogels showing one of the highest iodine-loading capacities reported to date in saturated conditions.
This paper describes the development and provides comparisons of thiolated (-SH) and unthiolated Ag-Al-Si-O xerogels for iodine gas capture. These xerogels were produced from alkoxides and then heat-treated at 350 degrees C to provide mechanical strength for subsequent processing steps. Then, a portion of the xerogels was thiolated using (3-mercaptopropyl)trimethoxysilane. Next, thiolated and unthiolated batches were ion-exchanged in AgNO3 solutions where Ag+ replaced Na+ in the gel network on a near 1:1 molar basis. Subsamples of the Ag-exchanged xerogels were subjected to a reduction step in H2/Ar to convert Ag+ to Ag0 where the rest of the Ag-exchanged (Ag+) were not reduced. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy revealed nanoscale Ag0 in the Ag+ samples despite no active reduction where actively reduced samples had bimodal Ag0 distribution of-,2-3 nm hexagonal and-,6-7 nm cubic crystallites. Synchrotron X-ray absorption spectroscopy was used to assess the oxidization states of Ag, S, and I within the different xerogel samples. The specific surface areas of the base xerogels decreased as subsequent treatments were performed on the as-made samples, albeit the decreases were smaller than aerogel equivalents of these samples from a previous study. All iodine-loaded Ag-based samples showed a mixture of beta-AgI and gamma-AgI. Comparisons of iodine-loading results with other Ag-based iodine sorbents show that the thiolated Ag0-xerogels in this work have one of the highest iodine-loading capacities (qe) reported to date in saturated conditions with the thiolated Ag0-xerogel showing 522 mg iodine per g of the sorbent.
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