The role of surface hydroxyls on the radiolysis of gibbsite and boehmite nanoplatelets

JOURNAL OF HAZARDOUS MATERIALS

卷:398

Article

Wang, Zheming¹  Walter, Eric D.²  Sassi, Michel¹  Zhang, Xin¹  Zhang, Hailin¹  Li, Xiaohong S.³  Chen, Ying²  Cui, Wenwen¹  Tuladhar, Aashish¹  Chase, Zizwe²  Winkelman, Austin D.^3,5,6  Wang, Hong-Fei⁴  Pearce, Carolyn, I³  Clark, Sue B.^3,5,6  Rosso, Kevin M.¹ 

[1] Pacific Northwest Natl Lab, Phys Sci Div, Richland, WA 99352 USA

[2] Pacific Northwest Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA

[3] Pacific Northwest Natl Lab, Energy & Environm Div, Richland, WA 99352 USA

[4] Fudan Univ, Shanghai, Peoples R China

[5] Fudan Univ, Dept Chem, 220 Handan Rd, Shanghai 200433, Peoples R China

[6] Fudan Univ, Shanghai Key Lab Mol Catalysis & Innovat Mat, 220 Handan Rd, Shanghai 200433, Peoples R China

关键词: Nuclear waste;    Radiolysis;    Sum frequency generation;    Gibbsite;    Boehmite;   

DOI  :  10.1016/j.jhazmat.2020.122853

来源: Elsevier

【 摘 要 】

Understanding mechanistic pathways to radiolytic hydrogen generation by metal oxyhydroxide nanomaterials is challenging because of the difficulties of distinguishing key locations of OH bond scission, from structural interiors to hydroxylated surfaces to physi-sorbed water molecules. Here we exploited the interface-selectivity of vibrational sum frequency generation (VSFG) to isolate surface versus bulk hydroxyl groups for gibbsite and boehmite nanoplatelets before and after Co-60 irradiation at dose levels of approximately 7.0 and 29.6 Mrad. While high-resolution microscopy revealed no effect on particle bulk and surface structures, VSFG results clearly indicated up to 83% and 94% radiation-induced surface OH bond scission for gibbsite and boehmite, respectively, a substantially higher proportion than observed for interior OH groups by IR and Raman spectroscopy. Electron paramagnetic spectroscopy revealed that the major radiolysis products bound in the mineral structures are trapped electrons, O-center dot, O-2(-center dot) and possibly F-centers in gibbsite, and H-center dot, O-center dot and O-3(-center dot) in boehmite, which persist on the time frame of several months. The entrapped radiolysis products appear to be highly stable, enduring re-hydration of particle surfaces, and likely reflect a permanent adjustment in the thermodynamic stabilities of these nanomaterials.

【 授权许可】

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