Effect of Adsorbed Carboxylates on the Dissolution of Boehmite Nanoplates in Highly Alkaline Solutions.

Autor: Zhao Y; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu Province 210023, China.; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Guo Q; Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States., Xue S; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Chen P; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Zhao Q; Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Liu L; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Hlushko H; Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States., LaVerne J; Radiation Laboratory and Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, United States., Pearce CI; Energy & Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Miao A; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu Province 210023, China., Wang Z; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Rosso KM; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Zhang X; Physical & Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
Jazyk: angličtina
Zdroj: Environmental science & technology [Environ Sci Technol] 2024 Jan 30; Vol. 58 (4), pp. 2017-2026. Date of Electronic Publication: 2024 Jan 12.
DOI: 10.1021/acs.est.3c06595
Abstrakt: Understanding the dissolution of boehmite in highly alkaline solutions is important to processing complex nuclear waste stored at the Hanford (WA) and Savannah River (SC) sites in the United States. Here, we report the adsorption of model carboxylates on boehmite nanoplates in alkaline solutions and their effects on boehmite dissolution in 3 M NaOH at 80 °C. Although expectedly lower than at circumneutral pH, adsorption of oxalate occurred at pH 13, with adsorption decreasing linearly to 3 M NaOH. Classical molecular dynamics simulations suggest that the adsorption of oxalate dianions onto the boehmite surface under high pH can occur through either inner- or outer-sphere complexation mechanisms depending on adsorption sites. However, both adsorption models indicate relatively weak binding, with an energy preference of 1.26 to 2.10 kcal/mol. By preloading boehmite nanoplates with oxalate or acetate, we observed suppression of dissolution rates by 23 or 10%, respectively, compared to pure solids. Scanning electron microscopy and transmission electron microscopy characterizations revealed no detectable difference in the morphologic evolution of the dissolving boehmite materials. We conclude that preadsorbed carboxylates can persist on boehmite surfaces, decreasing the density of dissolution-active sites and thereby adding extrinsic controls on dissolution rates.
Databáze: MEDLINE
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