Capacitive deionization (CDI) technologies have the potential to become cost-competitive alternatives to reverse osmosis for the treatment of brackish waters. In this study, we report our findings on the effect of co-ion sorption and faradaic side reactions on our ion exchange resin functionalized desalination electrodes which passively capture salt and reject it upon charging. This system, which we previously reported on and refer to as electrically regenerated ion exchange (ERI), avoids the use of expensive ion exchange membranes in an effort to save costs. Surprisingly, we find that, compared to a reference CDI system, ERI electrodes capture salt most effectively at low applied voltages (0.5 mg/cm3 at 0.8 V). Both CDI and ERI systems also seem to suffer from co-ion sorption effects which negatively impact salt adsorption. However, Faradaic side reactions at higher voltages (1 V and 1.2 V) which we track via pH measurements, serve as a detriment to CDI but seem to facilitate the functionality of ERI.

Demand for lithium for batteries and other green technologies is exploding. The industry must develop sustainable methods to remove and process the element from ores and brines to avoid environmental damage. [Figure not available: see fulltext.]

For the sake of water and energy conservation, development of latent heat cooling and thermal storage systems that minimize water consumption and operate with higher efficacy than their water-driven counterparts is a crucial task. Phase change materials (PCMs) present a potential solution, but their integration into real-world systems abounds with scientific challenges such as material toxicity, flammability, low thermal performance and lack of tunable phase-change temperatures. In this study we report on a first-in-class nanocomposite PCM that leverages non-flammable, non-toxic, high latent heat sugar alcohols (SAs) encapsulated within easy-to-synthesize zeolitic imidazolate framework (ZIF) crystals. We also outline a practical route for surface functionalization with hydrophilic and hydrophobic moieties. The SA@ZIF composites display suppressed phase-change temperatures which, together with alterable surface functionality, broadens their applicability to a plethora of working environments. Direct synthesis of the SA@ZIF composite generates nanoconfined SAs with phase-change temperatures as low as 19.8 °C and latent heats as high as 285 J g-1. This nanoconfinement-induced thermal phenomenon is conserved even after functionalization of the SA@ZIF crystal surface. We believe this study will lay the groundwork as a platform for next generation high performing, tunable PCMs to aid in the realization of waterless cooling systems.