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- ItemBest practice for electrochemical water desalination data generation and analysis(Maryland Heights, MO : Cell Press, 2023) Torkamanzadeh, Mohammad; Kök, Cansu; Burger, Peter Rolf; Ren, Panyu; Zhang, Yuan; Lee, Juhan; Kim, Choonsoo; Presser, VolkerElectrochemical desalination shows promise for ion-selective, energy-efficient water desalination. This work reviews performance metrics commonly used for electrochemical desalination. We provide a step-by-step guide on acquiring, processing, and calculating raw desalination data, emphasizing informative and reliable figures of merit. A typical experiment uses calibrated conductivity probes to relate measured conductivity to concentration. Using a standard electrochemical desalination cell with activated carbon electrodes, we demonstrate the calculation of desalination capacity, charge efficiency, energy consumption, and ion selectivity metrics. We address potential pitfalls in performance metric calculations, including leakage current (charge) considerations and aging of conductivity probes, which can lead to inaccurate results. The relationships between pH, temperature, and conductivity are explored, highlighting their influence on final concentrations. Finally, we provide a checklist for calculating performance metrics and planning electrochemical desalination tests to ensure accuracy and reliability. Additionally, we offer simplified spreadsheet tools to aid data processing, system design, estimations, and upscaling.
- ItemSelective Pb2+ removal and electrochemical regeneration of fresh and recycled FeOOH([Erscheinungsort nicht ermittelbar] : Tsinghua Press, 2023) Wang, Lei; Deligniere, Lexane; Husmann, Samantha; Leiner, Regina; Bahr, Carsten; Zhang, Shengjie; Dun, Chaochao; Montemore, Matthew M.; Gallei, Markus; Urban, Jeffrey J.; Kim, Choonsoo; Presser, VolkerHeavy metal pollution is a key environmental problem. Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously. Adsorption is a promising approach with a facile process, adaptability for the broad concentration of feed water, and high selectivity. However, the adsorption method faces challenges in synthesizing high-performance sorbents and regenerating adsorbents effectively. FeOOH is an environmentally friendly sorbent with low-cost production on a large scale. Nevertheless, the selectivity behavior and regeneration of FeOOH are seldom studied. Therefore, we investigated the selectivity of FeOOH in a mixed solution of Co2+, Ni2+, and Pb2+ and proposed to enhance the capacity of FeOOH and regenerate it by using external charges. Without charge, the FeOOH electrode shows a Pb2+ uptake capacity of 20 mg/g. After applying a voltage of −0.2/+0.8 V, the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%–80%. In 35 cycles, FeOOH shows a superior selectivity towards Pb2+ compared with Co2+ and Ni2+, with a purity of 97% ± 3% in the extracts. The high selectivity is attributed to the lower activation energy for Pb2+ sorption. The capacity retentions at the 5th and the 35th cycles are ca. 80% and ca. 50%, respectively, comparable to the chemical regeneration method. With industrially exhausted granular ferric hydroxide as the electrode material, the system exhibits a Pb2+ uptake capacity of 37.4 mg/g with high selectivity. Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent. [Figure not available: see fulltext.]