(536i) In-Situ Studies on Anion Electroadsorption Mechanisms

Phosphorus is present in many agricultural waste streams, and is appearing in water in an increasing concentration. The increased presence in surface water can contribute to eutrophication and be harmful to ecosystems. Thus, it is desirable to treat these water sources to either remove or recover the phosphorus. While there are many methods for separation, herein, we examine how materials can be engineered for electric field driven (electrochemical) recovery of phosphate anions from aqueous solutions[1]. This work will present a fundmental study using electrochemical atomic force microscopy to understand how electroadsorption processes are altered by varying phosphate anion charges (𝑃𝑂43−, 𝐻𝑃𝑂42−, 𝑎𝑛𝑑 𝐻3𝑃𝑂4−) [1,2,3]. The overarching goal of this work is to understand how phosphate anions electrostatically interact with porous materials exposed to an electrical bias in the formation of an electric double layer. Fundamental electrochemistry experiments will be presented on the effect of phosphate adsorption for energy storage in concentrated electrolytes as well as phosphate removal applications (dilute solutions). In-situ dilatometry experiments will be presented in order to quanitfy mechanical stresses due to the electroadsorption processes.

[1] Xie, Jie, et al. "Removal and recovery of phosphate from water by activated aluminum oxide and lanthanum oxide." Powder Technology 269 (2015): 351-357.

[2] Alliata, D., et al. "In situ AFM study of interlayer spacing during anion intercalation into HOPG in aqueous electrolyte." Langmuir 15.24 (1999): 8483-8489.

[3] Black, Jennifer M., et al. "Strain‐Based In Situ Study of Anion and Cation Insertion into Porous Carbon Electrodes with Different Pore Sizes." Advanced Energy Materials 4.3 (2014).