Abstract
Boehmite has been widely used in theoretical research and industry, especially for hazardous material processing. For the liquid-phase treating process, the interfacial properties of boehmite are believed to be affected by pH conditions, which change its physicochemical behavior. However, molecular-level detection on cluster ions is challenging when using bulk approaches. Herein we employ in situ vacuum ultraviolet single-photon ionization mass spectrometry (VUV SPI-MS) coupled with a vacuum-compatible microreactor system for analysis at the liquid–vacuum interface (SALVI) to investigate the solute molecular composition of boehmite under different pH conditions for the first time. The mass spectral results show that more complex clustering of solute molecules exists at the solid–liquid (s–l) interface than conventionally perceived in a “simple” aqueous solution. Besides solute ions, such as boehmite molecules and fragments, the composition and appearance energies of these newly discovered solvated cluster ions are determined by VUV SPI-MS in different pH solutions. We offer new results for the pH-dependent effect of boehmite and provide insights into a more detailed solvation mechanism at the s–l interface. By comparing the key products under different pH conditions, fundamental understanding of boehmite dissolution is revealed to assist the engineering design of waste processing and storage solutions.
| Original language | English |
|---|---|
| Article number | 7254 |
| Journal | International Journal of Molecular Sciences |
| Volume | 26 |
| Issue number | 15 |
| DOIs | |
| State | Published - Aug 2025 |
Funding
ORNL is managed by UT-Battelle, LLC, for the U.S. Department of Energy (DOE) under contract number DE-AC05-00OR22725 in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan , accessed on 1 June 2025). This research used resources of the Advanced Light Source (ALS), a DOE Office of Science User Facility under con-tract no. DE-AC02-05CH11231. The authors thank Musahid Ahmed, Oleg Kostko, Rachel Komorek, Jiachao Yu, and Tyler Troy for their assistance in sample preparation and data acquisition. Funding for experiments was supported by the strategic Laboratory Directed Research and Development (LDRD) of the Physical Sciences Directorate of the Oak Ridge National Laboratory (ORNL). Data analysis and paper writing for X.-Y.Y. were supported by the Office of Environmental Management (EM), U.S. Department of Energy (DOE), through the DOE National Laboratory Program Announcement Number LAB 23-EM001, Hanford Tank Waste Cleanup Research & Development (project 277636). Funding for X.S. was provided by Shandong Provincial Natural Science Foundation, grant number ZR2022QB137.
Keywords
- SALVI
- VUV SPI-MS
- appearance energy (AE)
- boehmite
- pH dependence
- water cluster