In Situ Electrochemical Dilatometry of Phosphate Anion Electrosorption

Here we investigate the competitive electrosorption of mono- and divalent phosphate anions through electrochemical desalination- and dilatometry-based experiments. Through in situ dilatometry, we monitor the strain at the electrode surface as anions and cations are electrosorbed. Strain measurements show that the presence of divalent ions promotes a greater than anticipated electrode expansion during cation (Na+) electrosorption. The expansion observed with Na+ equaled the expansion observed with HPO42–. Because the ionic radius of Na+ is smaller than that of HPO42–, the symmetric expansion suggests that divalent anions do not completely desorb during electrode regeneration, causing the adverse interactions with the cation during co-ion expulsion. This results in a decrease in desalination performance, indicated by a decreased salt adsorption capacity. Conversely, an expected asymmetric expansion during anion and cation electrosorption occurs with monovalent phosphate anions (H2PO4–), indicating that mono...

[1]  Kelsey B. Hatzell,et al.  Effect of oxidation of carbon material on suspension electrodes for flow electrode capacitive deionization. , 2015, Environmental science & technology.

[2]  Brooke K. Mayer,et al.  Total Value of Phosphorus Recovery. , 2016, Environmental science & technology.

[3]  T. A. Hatton,et al.  Redox-electrodes for selective electrochemical separations. , 2017, Advances in colloid and interface science.

[4]  C. Tsouris,et al.  Electrosorption selectivity of ions from mixtures of electrolytes inside nanopores. , 2008, The Journal of chemical physics.

[5]  Mark C M van Loosdrecht,et al.  Looking beyond struvite for P-recovery. , 2013, Environmental science & technology.

[6]  Sergei V. Kalinin,et al.  Bias-dependent molecular-level structure of electrical double layer in ionic liquid on graphite. , 2013, Nano letters.

[7]  Sergei V. Kalinin,et al.  Strain‐Based In Situ Study of Anion and Cation Insertion into Porous Carbon Electrodes with Different Pore Sizes , 2014 .

[8]  Marta C. Hatzell,et al.  Influence of Feed-Electrode Concentration Differences in Flow-Electrode Systems for Capacitive Deionization , 2018, Industrial & Engineering Chemistry Research.

[9]  Joseph C. Farmer,et al.  Capacitive Deionization of NaCl and NaNO3 Solutions with Carbon Aerogel Electrodes , 1996 .

[10]  Y. Huang,et al.  Capacitive deionization (CDI) for removal of phosphate from aqueous solution , 2014 .

[11]  Kelsey B. Hatzell,et al.  A Combined Heat- and Power-Driven Membrane Capacitive Deionization System , 2017 .

[12]  Jianyu Sun,et al.  A novel electrochemical reactor for nitrogen and phosphorus recovery from domestic wastewater , 2017, Frontiers of Environmental Science & Engineering.

[13]  Linda Zou,et al.  A study of the capacitive deionisation performance under various operational conditions. , 2012, Journal of hazardous materials.

[14]  M. Bazant,et al.  Thermodynamics of Ion Separation by Electrosorption. , 2018, Environmental science & technology.

[15]  M. Hatzell,et al.  Efficiency of Carnot and Conventional Capacitive Deionization Cycles , 2018, The Journal of Physical Chemistry C.

[16]  Hongtao Zhang,et al.  A study of electrosorption selectivity of anions by activated carbon electrodes in capacitive deionization. , 2015 .

[17]  Michael Stadermann,et al.  Energy breakdown in capacitive deionization. , 2016, Water research.

[18]  M. Bazant,et al.  Anisometric Charge Dependent Swelling of Porous Carbon in an Ionic Liquid , 2013, 1306.2071.