Vanadium Electrolyte for All-Vanadium Redox-Flow Batteries: The Effect of the Counter Ion

In this study, 1.6 M vanadium electrolytes in the oxidation forms V(III) and V(V) were prepared from V(IV) in sulfuric (4.7 M total sulphate), V(IV) in hydrochloric (6.1 M total chloride) acids, as well as from 1:1 mol mixture of V(III) and V(IV) (denoted as V3.5+) in hydrochloric (7.6 M total chloride) acid. These electrolyte solutions were investigated in terms of performance in vanadium redox flow battery (VRFB). The half-wave potentials of the V(III)/V(II) and V(V)/V(IV) couples, determined by cyclic voltammetry, and the electronic spectra of V(III) and V(IV) electrolyte samples, are discussed to reveal the effect of electrolyte matrix on charge-discharge behavior of a 40 cm2 cell operated with 1.6 M V3.5+ electrolytes in sulfuric and hydrochloric acids. Provided that the total vanadium concentration and the conductivity of electrolytes are comparable for both acids, respective energy efficiencies of 77% and 72–75% were attained at a current density of 50 mA∙cm−2. All electrolytes in the oxidation state V(V) were examined for chemical stability at room temperature and +45 °C by titrimetric determination of the molar ratio V(V):V(IV) and total vanadium concentration.

Contactless, probeless and non-titrimetric determination of acid–base reactions using broadband acoustic resonance dissolution spectroscopy (BARDS)

Carbon dioxide production due to an acid–base reaction.

Preparation and Antimicrobial Evaluation of Neem Oil Alkyd Resin and Its Application as Binder in Oil-Based Paint

<p class="1Body">Neem oil Alkyd resin (NOAR) was synthesized by alcoholysis and polycondensation using glycerol and phthalic anhydride respectively at 230-250°C. The alkyd resin was characterized by FT-IR spectroscopy, viscometry, solubility in various solvents and antimicrobial activity against some selected bacterial species. FT-IR analyses indicated the successful synthesis of alkyd resin as also evident from titrimetric determination of acid number of the mixture which decreases as the reaction progresses. Microbiological analyses of the resin show that it is active against some selected bacterial specie particularly at concentrations of 100 and 50mg/ml in DMSO. The synthesized resin was used as binder in the formulation of oil-based paints using varying resin concentration i.e. 0, 10, and 20% w/v. The prepared paints were found to have excellent fastness properties to light, water, alkali but poor to xylene. The results obtained suggested that NOAR can serve as binder with potential applications in the production of antimicrobial paints.</p>