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In this work, conductive-diamond electrochemical oxidation of synthetic wastes polluted with azoic dyes is studied. Results show that this advanced oxidation process is able to complete the treatment of wastes polluted with large molecules such as the dyes studied in this work. The oxidation process starts with the breakage of the azoic group, and according to the changes in the total organic carbon and chemical oxygen demand observed during the electrolyses, it deals with the accumulation of carboxylic acids in the final stages of the treatment. Negligible amounts of refractory organic matter are found in the effluent of highly loaded waste treatment. The efficiency of the conductive-diamond electrolyses of azoic dyes does not seem to depend on the molecule of the dye oxidized but only on its concentration range. From the experimental results it seems that the primary mechanisms in the oxidation of dyes are the mediated electrooxidation by hydroxyl radicals and persulfate (highly loaded wastes) and by persulfate (diluted wastes).

As an alternative to commercial Ni-and Co-based intercalation-type cathode materials, conversion-type metal fluoride (MF x ) cathodes are attracting more interest due to their promisses to increase cell-level energy density when coupled with lithium (Li) or silicon (Si)-based anodes. Among metal fluorides, iron fluorides (FeF 2 and FeF 3 ) are regarded as some of the most promising candidates due to their high capacity, moderately high potential and very low cost of Fe. In this study, we systematically investigated the impacts of electrolyte composition on the performance and stability of nanostructured FeF 2 cathodes.We discovered dramatic impacts of Li salt composition, Li salt concentration, solvent composition and cycling potential range on the cathode most critical performance parameters -stability, capacity, rate and voltage hysteresis. In contrast to previous beliefs, we observed that even if the Fe 2+ cation dissolution could be avoided, the dissolution of Fanions may still negatively affect cathode performance. Formation of the more favorable cathode solid electrolyte interface (CEI) was found to minimize both processes.

Summary The global demand for high performance and environmentally friendly energy storage systems leads to intensive research on new and advanced electrode materials that are able to satisfy the fast‐growing global market in various applications. The 2D graphene material is one of the most promising candidates for next‐generation energy storage applications, particularly supercapacitor devices due to its exceptional intrinsic properties such as highest theoretical specific surface area (2600 m2/g), high electrical charges mobility (230 000 cm2/V·s), thermal conductivity (3000 W/mK), and highest strength (130 GPa). This comprehensive review summarizes the most recent progress made on the graphene material in its different structural forms of foams (3D), thin films (2D), nano‐fibers (1D), and nano‐dotes (0D) for supercapacitor electrodes. It initiates with a brief historical introduction on graphene discovery and its current production techniques that retain its intrinsic properties ranging from mechanical exfoliation of graphene in high quality to its epitaxial growth by chemical vapor deposition on metal substrates and its derivation by chemical reduction of graphene oxide. In addition to highlighting its main characterization techniques such as Raman spectroscopy, atomic force microscopy, and transmission electron microscopy, as well as, its critical properties including electrical, optical, mechanical, and thermal properties. Its potential applications are also illustrated with emphasizing on its usage as an electrode material in supercapacitors. Finally, its main challenges and future prospects are considerably pointed out.

Highlights Hydroxychloroquine (HCQ) has the potential to be a persistent pollutant in water. Electrochemical oxidation with BDD anode (EO) degraded HCQ in all tested conditions. EO led to the release of Cl − ions and conversion of organic nitrogen to NO 3 − and NH 4 +. EO combined with UV light or ultrasound enhanced degradation kinetics and efficiency. Due to higher production of oxidants, EO combined with UV light used much less energy.