Capacitive Deionization -- defining a class of desalination technologies

Over the past decade, capacitive deionization (CDI) has realized a surge in attention in the field of water desalination and can now be considered as an important technology class, along with reverse osmosis and electrodialysis. While many of the recently developed technologies no longer use a mechanism that follows the strict definition of the term "capacitive", these methods nevertheless share many common elements that encourage treating them with similar metrics and analyses. Specifically, they all involve electrically driven removal of ions from a feed stream, storage in an electrode (i.e., ion electrosorption) and release, in charge/discharge cycles. Grouping all these methods in the technology class of CDI makes it possible to treat evolving new technologies in standardized terms and compare them to other technologies in the same class

High capacity silicon anodes enabled by MXene viscous aqueous ink

The ever-increasing demands for advanced lithium-ion batteries have greatly stimulated the quest for robust electrodes with a high areal capacity. Producing thick electrodes from a high-performance active material would maximize this parameter. However, above a critical thickness, solution-processed films typically encounter electrical/mechanical problems, limiting the achievable areal capacity and rate performance as a result. Herein, we show that two-dimensional titanium carbide or carbonitride nanosheets, known as MXenes, can be used as a conductive binder for silicon electrodes produced by a simple and scalable slurry-casting technique without the need of any other additives. The nanosheets form a continuous metallic network, enable fast charge transport and provide good mechanical reinforcement for the thick electrode (up to 450 µm). Consequently, very high areal capacity anodes (up to 23.3 mAh cm−2) have been demonstrated

Monitoring Toxicity Associated with Parenteral Sodium Stibogluconate in the Day-Case Management of Returned Travellers with New World Cutaneous Leishmaniasi

Sodium stibogluconate (SbV), a pentavalent antimonial, administered parenterally, is the recommended treatment for South American cutaneous leishmaniasis, caused by Leishmania Viannia, which is a neglected disease that affects many people resident in Central and South America, as well as travellers to the areas. Antimonials have been used for the treatment of leishmaniasis since the 1930s. We report the toxicity experienced by a series of NWCL patients receiving SbV in a resource-rich setting. This study also evaluates administration of the drug to patients without admitting them to hospital. The administration of parenteral SbV was associated with myelosuppression, derangement of markers of liver function and prolongation of the QT interval on electrocardiography, although these effects were not found to be associated with adverse clinical events, and the majority of doses of SbV were administered without cause for hospital admission. Our data shows that parenteral SbV treatment may be provided with reduced monitoring for toxicity than is currently done, and on an outpatient-basis, without endangering safety. Such practice, with reduced demands on local finances and the healthcare workforce, would be desirable in more resource-limited settings

Biological approaches to artificial photosynthesis: general discussion

Metals in Catalysis, Biomimetics & Inorganic Material

Synthetic approaches to artificial photosynthesis: general discussion

Metals in Catalysis, Biomimetics & Inorganic Material

The Role of Adventitious Carbon in Photo-catalytic Nitrogen Fixation by Titania.

Photo-catalytic fixation of nitrogen by titania catalysts at ambient conditions has been reported for decades, yet the active site capable of adsorbing an inert N2 molecule at ambient pressure and the mechanism of dissociating the strong dinitrogen triple bond at room temperature remain unknown. In this work in situ near-ambient-pressure X-ray photo-electron spectroscopy and density functional theory calculations are used to probe the active state of the rutile (110) surface. The experimental results indicate that photon-driven interaction of N2 and TiO2 is observed only if adventitious surface carbon is present, and computational results show a remarkably strong interaction between N2 and carbon substitution (C*) sites that act as surface-bound carbon radicals. A carbon-assisted nitrogen reduction mechanism is proposed and shown to be thermodynamically feasible. The findings provide a molecular-scale explanation for the long-standing mystery of photo-catalytic nitrogen fixation on titania. The results suggest that controlling and characterizing carbon-based active sites may provide a route to engineering more efficient photo(electro)-catalysts and improving experimental reproducibility

The Role of Adventitious Carbon in Photo-catalytic Nitrogen Fixation by Titania.

Photo-catalytic fixation of nitrogen by titania catalysts at ambient conditions has been reported for decades, yet the active site capable of adsorbing an inert N2 molecule at ambient pressure and the mechanism of dissociating the strong dinitrogen triple bond at room temperature remain unknown. In this work in situ near-ambient-pressure X-ray photo-electron spectroscopy and density functional theory calculations are used to probe the active state of the rutile (110) surface. The experimental results indicate that photon-driven interaction of N2 and TiO2 is observed only if adventitious surface carbon is present, and computational results show a remarkably strong interaction between N2 and carbon substitution (C*) sites that act as surface-bound carbon radicals. A carbon-assisted nitrogen reduction mechanism is proposed and shown to be thermodynamically feasible. The findings provide a molecular-scale explanation for the long-standing mystery of photo-catalytic nitrogen fixation on titania. The results suggest that controlling and characterizing carbon-based active sites may provide a route to engineering more efficient photo(electro)-catalysts and improving experimental reproducibility

Effect of Oxidation of Carbon Material on Suspension Electrodes for Flow Electrode Capacitive Deionization

Flow electrode deionization (FCDI) is an emerging area for continuous and scalable deionization, but the electrochemical and flow properties of the flow electrode need to be improved to minimize energy consumption. Chemical oxidation of granular activated carbon (AC) was examined here to study the role of surface heteroatoms on rheology and electrochemical performance of a flow electrode (carbon slurry) for deionization processes. Moreover, it was demonstrated that higher mass densities could be used without increasing energy for pumping when using oxidized active material. High mass-loaded flow electrodes (28% carbon content) based on oxidized AC displayed similar viscosities (∼21 Pa s) to lower mass-loaded flow electrodes (20% carbon content) based on nonoxidized AC. The 40% increased mass loading (from 20% to 28%) resulted in a 25% increase in flow electrode gravimetric capacitance (from 65 to 83 F g^–1) without sacrificing flowability (viscosity). The electrical energy required to remove ∼18% of the ions (desalt) from of the feed solution was observed to be significantly dependent on the mass loading and decreased (∼60%) from 92 ± 7 to 28 ± 2.7 J with increased mass densities from 5 to 23 wt %. It is shown that the surface chemistry of the active material in a flow electrode effects the electrical and pumping energy requirements of a FCDI system