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   https://doi.org/10.1021/acs.chemmater.1c04061  

   Wang, Louis S.; Patel, Sawankumar V.; Truong, Erica; Hu, Yan-Yan; Haile, Sossina M. (February 2022, Chemistry of Materials)
2. Transient Struvite Formation during Stoichiometric (1:1) NH ₄ ⁺ and PO ₄ ^3– Adsorption/Reaction on Magnesium Oxide (MgO) Particles

   https://doi.org/10.1021/acssuschemeng.8b05318  

   Kiani, Daniyal; Sheng, Yiying; Lu, Baoying; Barauskas, Dovydas; Honer, Kenneth; Jiang, Zhe; Baltrusaitis, Jonas (November 2018, ACS Sustainable Chemistry & Engineering)
3. Spatially Resolved Product Speciation during Struvite Synthesis from Magnesite (MgCO ₃ ) Particles in Ammonium (NH ₄ ⁺ ) and Phosphate (PO ₄ ^3– ) Aqueous Solutions

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4. A Non‐aqueous H ₃ PO ₄ Electrolyte Enables Stable Cycling of Proton Electrodes

   https://doi.org/10.1002/anie.202010554  

   Xu, Yunkai; Wu, Xianyong; Jiang, Heng; Tang, Longteng; Koga, Kenneth Y.; Fang, Chong; Lu, Jun; Ji, Xiulei (September 2020, Angewandte Chemie International Edition)

   Abstract A non‐aqueous proton electrolyte is devised by dissolving H₃PO₄into acetonitrile. The electrolyte exhibits unique vibrational signatures from stimulated Raman spectroscopy. Such an electrolyte exhibits unique characteristics compared to aqueous acidic electrolytes: 1) higher (de)protonation potential for a lower desolvation energy of protons, 2) better cycling stability by dissolution suppression, and 3) higher Coulombic efficiency owing to the lack of oxygen evolution reaction. Two non‐aqueous proton full cells exhibit better cycling stability, higher Coulombic efficiency, and less self‐discharge compared to the aqueous counterpart. 

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5. Removal of Aqueous Uranyl and Arsenate Mixtures after Reaction with Limestone, PO ₄ ^3– , and Ca ²⁺

   https://doi.org/10.1021/acs.est.3c03809  

   Meza, Isabel; Hua, Han; Gagnon, Kaelin; Mulchandani, Anjali; Gonzalez-Estrella, Jorge; Burns, Peter C.; Ali, Abdul-Mehdi S.; Spilde, Michael; Peterson, Eric; Lichtner, Peter; et al (December 2023, Environmental Science & Technology)

   The co-occurrence of uranyl and arsenate in contaminated water caused by natural processes and mining is a concern for impacted communities, including in Native American lands in the U.S. Southwest. We investigated the simultaneous removal of aqueous uranyl and arsenate after the reaction with limestone and precipitated hydroxyapatite (HAp, Ca10(PO4)6(OH)2). In benchtop experiments with an initial pH of 3.0 and initial concentrations of 1 mM U and As, uranyl and arsenate coprecipitated in the presence of 1 g L−1 limestone. However, related experiments initiated under circumneutral pH conditions showed that uranyl and arsenate remained soluble. Upon addition of 1 mM PO43− and 3 mM Ca2+ in solution (initial concentration of 0.05 mM U and As) resulted in the rapid removal of over 97% of U via Ca−U−P precipitation. In experiments with 2 mM PO4 3− and 10 mM Ca2+ at pH rising from 7.0 to 11.0, aqueous concentrations of As decreased (between 30 and 98%) circa pH 9. HAp precipitation in solids was confirmed by powder X-ray diffraction and scanning electron microscopy/energy dispersive X-ray. Electron microprobe analysis indicated U was coprecipitated with Ca and P, while As was mainly immobilized through HAp adsorption. The results indicate that natural materials, such as HAp and limestone, can effectively remove uranyl and arsenate mixtures. 

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