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- ItemMXene as a novel intercalation-type pseudocapacitive cathode and anode for capacitive deionization(London [u.a.] : RSC, 2016) Srimuk, Pattarachai; Kaasik, Friedrich; Krüner, Benjamin; Tolosa, Aura; Fleischmann, Simon; Jäckel, Nicolas; Tekeli, Mehmet C.; Aslan, Mesut; Suss, Matthew E.; Presser, VolkerIn this proof-of-concept study, we introduce and demonstrate MXene as a novel type of intercalation electrode for desalination via capacitive deionization (CDI). Traditional CDI cells employ nanoporous carbon electrodes with significant pore volume to achieve a large desalination capacity via ion electrosorption. By contrast, MXene stores charge by ion intercalation between the sheets of its two-dimensional nanolamellar structure. By this virtue, it behaves as an ideal pseudocapacitor, that is, showing capacitive electric response while intercalating both anions and cations. We synthesized Ti3C2-MXene by the conventional process of etching ternary titanium aluminum carbide i.e., the MAX phase (Ti3AlC2) with hydrofluoric acid. The MXene material was cast directly onto the porous separator of the CDI cell without added binder, and exhibited very stable performance over 30 CDI cycles with an average salt adsorption capacity of 13 ± 2 mg g−1.
- ItemDual-Zinc Electrode Electrochemical Desalination(Weinheim : Wiley-VCH Verlag, 2020) Dai, J.; Wang, J.; Hou, X.; Ru, Q.; He, Q.; Srimuk, P.; Presser, V.; Chen, F.Continuous and low-energy desalination technologies are in high demand to enable sustainable water remediation. Our work introduces a continuous desalination process based on the redox reaction of a dual-zinc electrode. The system consists of two zinc foils as redox electrodes with flowing ZnCl2 electrolyte, concentrated and diluted salt streams with three anion- and cation-exchange membranes (AEM and CEM) separated configuration (AEM|CEM|AEM). If a constant current is applied, the negative zinc electrode is oxidized, and electrons are released to the external circuit, whereas the positive zinc electrode is reduced, causing salt removal in the dilution stream. The results showed that brackish water can be directly desalted to 380.6 ppm during a continuous batch-mode process. The energy consumption can be as low as 35.30 kJ mol−1 at a current density of 0.25 mA cm−2, which is comparable to reverse osmosis. In addition, the dual-zinc electrode electrochemical desalination demonstrates excellent rate performance, reversibility, and batch cyclability through electrode exchange regeneration. Our research provides a route for continuous low-energy desalination based on metal redox mediators.
- ItemHigh-performance ion removal via zinc–air desalination(Amsterdam : Elsevier, 2020) Srimuk, P.; Wang, L.; Budak, Ö.; Presser, V.Electrochemical processes enable a new generation of energy-efficient desalination technologies. While ion electrosorption via capacitive deionization is only suitable for brackish water with low molar strength, the use of Faradaic materials capable of reversible ion intercalation or conversion reactions allows energy-efficient removal of ions from seawater. However, the limited charge transfer/storage capacity of Faradaic materials indicates an upper limit for their desalination applications. Therefore, a new electrochemical concept must be explored to exceed the current state-of-the-art results and to push the desalination capacity beyond 100–200 mgNaCl/gelectrode. In this proof-of-concept work, we introduce the new concept of using metal–air battery technology for desalination. We do so by presenting performance data for zinc–air desalination (ZAD) in 600 mM NaCl. The ZAD cell provides a desalination capacity of 0.9–1.0 mgNaCl/cm2 (normalized to the membrane area; corresponding to 1300 mgNaCl/gZn) with a charge efficiency of 70% when charging/discharging the cell at 1 mA/cm2. The energy consumption of ZAD is 68–92 kJ/mol.
- ItemEmerging, hydrogen-driven electrochemical water purification(Amsterdam [u.a.] : Elsevier Science, 2022) Suss, M.E.; Zhang, Y.; Atlas, I.; Gendel, Y.; Ruck, E.B.; Presser, V.Energy-efficient technologies for the remediation of water and generation of drinking water is a key towards sustainable technologies. Electrochemical desalination technologies are promising alternatives towards established methods, such as reverse osmosis or nanofiltration. In the last few years, hydrogen-driven electrochemical water purification has emerged. This review article explores the concept of desalination fuel cells and capacitive-Faradaic fuel cells for ion separation.
- ItemHigh performance stability of titania decorated carbon for desalination with capacitive deionization in oxygenated water(London : RSC Publishing, 2016) Srimuk, Pattarachai; Ries, Lucie; Zeiger, Marco; Fleischmann, Simon; Jäckel, Nicolas; Tolosa, Aura; Krüner, Benjamin; Aslan, Mesut; Presser, VolkerPerformance stability in capacitive deionization (CDI) is particularly challenging in systems with a high amount of dissolved oxygen due to rapid oxidation of the carbon anode and peroxide formation. For example, carbon electrodes show a fast performance decay, leading to just 15% of the initial performance after 50 CDI cycles in oxygenated saline solution (5 mM NaCl). We present a novel strategy to overcome this severe limitation by employing nanocarbon particles hybridized with sol–gel-derived titania. In our proof-of-concept study, we demonstrate very stable performance in low molar saline electrolyte (5 mM NaCl) with saturated oxygen for the carbon/metal oxide hybrid (90% of the initial salt adsorption capacity after 100 cycles). The electrochemical analysis using a rotating disk electrode (RDE) confirms the oxygen reduction reaction (ORR) catalytic effect of FW200/TiO2, preventing local peroxide formation by locally modifying the oxygen reduction reaction.
- ItemLow voltage operation of a silver/silver chloride battery with high desalination capacity in seawater(London : Royal Society of Chemistry, 2019) Srimuk, P.; Husmann, S.; Presser, V.Technologies for the effective and energy efficient removal of salt from saline media for advanced water remediation are in high demand. Capacitive deionization using carbon electrodes is limited to highly diluted salt water. Our work demonstrates the high desalination performance of the silver/silver chloride conversion reaction by a chloride ion rocking-chair desalination mechanism. Silver nanoparticles are used as positive electrodes while their chlorination into AgCl particles produces the negative electrode in such a combination that enables a very low cell voltage of only Δ200 mV. We used a chloride-ion desalination cell with two flow channels separated by a polymeric cation exchange membrane. The optimized electrode paring between Ag and AgCl achieves a low energy consumption of 2.5 kT per ion when performing treatment with highly saline feed (600 mM NaCl). The cell affords a stable desalination capacity of 115 mg g-1 at a charge efficiency of 98%. This performance aligns with a charge capacity of 110 mA h g-1. © The Royal Society of Chemistry.