Electrochemical preparation of solid ferrates(VI)

The electrochemical methodologies for synthesis of BaFeO4 and Ag2FeO4 are presented in this article. The first step was to prepare a solution of the K2FeO4 as starting reagent by anodic dissolution in the transpassive potential region of the electrical steel in 10M KOH. The current density applied was fixed at 20 mA/cm2 at 55°C. Solid BaFeO4 and Ag2FeO4 were precipitated from K2FeO4 solution by the addition of Ba(OH)2 8H2O and AgNO3 solutions, respectively. The yield of solid salt synthesized was calculated by the hromitne titration, while their phase composition was determined by XRD analysis. Significant decomposition for BaFeO4 stored in dry conditions was not observed. Solid phase synthesized Ag2FeO4 is less stable than BaFeO4 due to its high sensitivity to light and susceptibility in such conditions to degradation to Ag2O, and AgO

Investigation of electrochemical synthesis of ferrate, Part I: Electrochemical behavior of iron and its several alloys in concentrated alkaline solutions

In recent years, considerable attention has been paid to various applications of Fe(VI) due to its unique properties such as oxidizing power, selective reactivity, stability of the salt, and non-toxic decomposition by-products of ferric ion. In environmental remediation processes, Fe(VI) has been proposed as green oxidant, coagulant, disinfectant, and antifoulant. Therefore, it is considered as a promising multi-purpose water treatment chemical. Fe(VI) has also potential applications in electrochemical energy source, as 'green cathode'. The effectiveness of ferrate as a powerful oxidant in the entire pH range, and its use in environmental applications for the removal of wide range of contaminants has been well documented by several researchers. There is scientific evidence that ferrate can effectively remove arsenic, algae, viruses, pharmaceutical waste, and other toxic heavy metals. Although Fe(VI) was first discovered in early eighteen century, detailed studies on physical and chemical properties of Fe(VI) had to wait until efficient synthetic and analytical methods of Fe(VI) were developed by Schreyer et al. in the 1950s. Actually, there have been developed three ways for the preparation of Fe(VI) compounds : the wet oxidation of Fe(II) and Fe(III) compounds, the dry oxidation of the same, and the electrochemistry method, mainly based on the trans passive oxidation of iron. High purity ferrates Fe(VI) can be generated when electrode of the pure iron metal or its alloys are anodized in concentrated alkaline solution. It is known that the efficiency of electrochemical process of Fe(VI) production depends on many factors such as current density, composition of anode material, types of electrolyte etc. In this paper, the electrochemical synthesis of ferrate(VI) solution by the anodic dissolution of iron and its alloys in concentrated water solution of NaOH and KOH is investigated. The process of transpassive dissolution of iron to ferrate(VI) was studied by cyclic voltammetry, galvanostatic and potentiostatic pulse method. Cyclic voltammetry gave useful data on potential regions where ferrate(VI) formation is to be expected in the course of transpassive anodic oxidation of iron and some of its alloys, and its stability in the electrolytes of different composition. In addition, step-wise oxidation of iron in anodic oxidation is confirmed. Galvanostatic pulse experiments confirmed the character of successive anodic oxidation of iron, as the three-step process of ferrate(VI) formation is clearly observed. In the cathodic pulse complex reduction of ferrate (VI), firstly to Fe(III) species and then to mixed Fe(II) and Fe(III) compounds and finally to elementary iron is confirmed. The significant difference between the mechanisms of anodic oxidation of pure iron and low carbon steel at the one side and electrical ferrous-silicon steel at the other is observed. The influence of material chemical composition on the electrochemical behavior of electrode in course of anodic polarization in strong alkaline solutions is discussed in terms of composition of passivating layer formed on the electrode. On the base of the experimental data, efficient synthesis of ferrate(VI) can be expected in the region of anodic potentials between + 0,55 and + 0,75 V against Hg|HgO reference electrode in the same solution, depending on the anode materials composition, in the alkaline electrolytes concentration between 10 and 15 M

Environmentally friendly disinfectant: Production, disinfectant action and efficiency

Silver is a known disinfectant from ancient times, and it has been widely used for various purposes: for food and water disinfection, curing of wounds and as a universal antibiotic for a wide spectrum of diseases - until the Second World War and the discovery of penicillin. Until recently, it was assumed that silver, being a heavy metal, was toxic for humans and living beings. However, the newest research provides facts that the usage of silver, even for drinking water disinfection, is benign if it is added in small concentrations (in parts per billion). It has been shown in the newer scientific and technical literature that silver in colloidal form is a powerful (secondary) disinfectant for drinking water, that it can be effectively used for the disinfection of water containers including swimming pools, installations in food industry, medicine, etc. Particularly, it has been shown that colloidal silver combined with hydrogen peroxide shows synergism having strong bactericidal and antiviral effects. The combination can be successfully used as a disinfectant in agriculture, food production and medicine. The original electrochemical process of production, the mechanism of physical-chemical reactions in that process and the mechanism of the antiseptic affect of the environmentally friendly disinfectant, based on the synergism of colloidal silver and hydrogen peroxide and the activity of electrochemically activated water, is shown. The starting solution was anolyte, obtained in electrochemical activation by water electrolysis of a highly diluted solution of K-tartarate in demineralized water (5.5-1CT4 M). The problem of electrolysis of very dilute aqueous solutions in membrane cells was particularly treated. It was shown that the efficiency of the electrolysis depends on the competition between the two processes: the rates of the processes of hydrogen and oxygen generation at the electrodes and the process of diffusion of hydrogen and hydroxyl ions through the cell membrane. Relatively strong disinfectant and sterilization action on standard races of gram-positive and gram-negative bacteria, blast spores and spores, as well as the safety of implementation of an environmentally friendly disinfectant was certified in a relevant institution, the Military Academy of Medicine in Belgrade

The effect of the COVID-19 pandemic on severe asthma care in Europe: Will care change for good?

peer reviewedBackground The coronavirus disease 2019 (COVID-19) pandemic has put pressure on healthcare services, forcing the reorganisation of traditional care pathways. We investigated how physicians taking care of severe asthma patients in Europe reorganised care, and how these changes affected patient satisfaction, asthma control and future care. Methods In this European-wide cross-sectional study, patient surveys were sent to patients with a physician-diagnosis of severe asthma, and physician surveys to severe asthma specialists between November 2020 and May 2021. Results 1101 patients and 268 physicians from 16 European countries contributed to the study. Common physician-reported changes in severe asthma care included use of video/phone consultations (46%), reduced availability of physicians (43%) and change to home-administered biologics (38%). Change to phone/video consultations was reported in 45% of patients, of whom 79% were satisfied or very satisfied with this change. Of 709 patients on biologics, 24% experienced changes in biologic care, of whom 92% were changed to home-administered biologics and of these 62% were satisfied or very satisfied with this change. Only 2% reported worsening asthma symptoms associated with changes in biologic care. Many physicians expect continued implementation of video/phone consultations (41%) and home administration of biologics (52%). Conclusions Change to video/phone consultations and home administration of biologics was common in severe asthma care during the COVID-19 pandemic and was associated with high satisfaction levels in most but not all cases. Many physicians expect these changes to continue in future severe asthma care, though satisfaction levels may change after the pandemic. © The authors 2022