Studies on electrochemical dissolution of sintered molybdenum discs as a potential method for targets dissolution in 99mTc production

Electrochemical dissolution of pressed into discs and sintered metallic molybdenum powder with the mass of 712 ± 10 mg (n = 15) in potassium hydroxide solution was studied in detail. The technique was considered to apply for dissolution of irradiated 100Mo target in the 99mTc production. The effect of various parameters, e.g., the concentration of the electrolyte solution, temperature, current density, and surface area of the platinum cathode, was investigated. The shortest time for total dissolution of molybdenum target was 70 min. This result was achieved using an electrolyte solution of 5 M KOH, temperature 55 °C and the current density of 365 mA/cm2.

P.fragi/ Graphene-gold Hybrid Nanomaterial Bioanode Based Microbial Fuel Cell

A Pseudomonas fragi (P.fragi) and Graphene-gold hybrid nanomaterial included carbon felt electrode (Graphene-Au/CFE) bioanode was developed and optimized. Then this bioanode was combined with a platinum cathode and a single...

Graphite electrodes as bioanodes for enzymatic glucose biofuel cell

This study investigates the performance of pencil graphite (PG) electrodes to identify the grade of pencil most suitable as bioanode for enzymatic glucose biofuel cell. Pencils of H, 3H, 5H and B grades are selected for this study. The surfaces of different grade PGs are modified with carboxylic acid functionalized multi walled carbon nanotubes (COOH-MW­CNT/PG), followed by immobilization with glucose oxidase (GOx) to fabricate the respect­tive bioanodes (GOx/COOH-MWCNT/PG). Morphological and electrochemical characteri­zations are carried out using scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry and energy dispersive X-ray spectroscopy. All tested PG electrodes exhibited positive results with variable response characteristics towards glucose oxidation reaction. B-grade PG bioanode is found to have the highest coverage of the deposited nanobiocomposite with the fastest electron transfer rate. The half-cell electrode assembly with this grade of PG recorded the highest current density of 4.25 mA cm-2 at physiological glucose conditions (5 mM glucose, pH 7.0). Enzymatic glucose biofuel cell assembled with B-grade PG bioanode and platinum cathode generated an open circuit potential of 149 mV and maximum power density of 0.789 µW cm−2 from 5 mM glucose at ambient conditions (25 ± 3◦C). The results obtained for B-grade PG bioanode are comparable to those of conventional carbon and glassy carbon electrodes, thus demonstrating its applicability to enzymatic glucose biofuel cells.

Utilization of Dissociation Constant (pKa) Value Perspective of -CH Acid in Electrochemical Synthesis of 4H-Chromene and its Derivatives

Activation of acidic-H in C-H chemistry through imposition of proper electrode potential is a matter of concern among synthetic research community. In this study, our main aim is to get deeper insight into the dissociation constant (pKa) value perspective of -CH acid and its utilization in electro-catalytic transformation. Herein, a platinum cathode was being used to attract a covalently bonded electrons that exist between C and active-H of CH-acid (dimedone) toward itself i.e. cathodic part to form acidic-H and thus, form in-situ tautomeric enol form that acts as electro-generated base. Utilization of this notability has been accomplished by electrochemical synthesis of 4H-chromene and its derivatives by performing cathodic reduction. Due to acidic property of dimedone, cathodic platinum electrode draw the potential switched to lower side that is being recorded through the potential-cum-galvanostat which facilitates the faster transfer of electrons from -CH acid to form enolate ion of dimedone that act as electro-generated base for the reaction media which simultaneously undergoes cascade reaction (Michael addition/cyclization) on activated alkene (α-cyanocinnamonitrile derivatives). This approach offers several advantages such as good yield, mild reaction condition, easy accessible, simple work-up procedure and controlled potential selectivity at cathode. Use of no base is pivotal section of this methodology. Electro-generated base is used instead of chemical toxic bases, so the present protocol is green as electrons that acts as intrinsically sole reagent for the reaction media which is renewable, hence sustainable for the safe future.

Membrane Extraction and Electrodeposition of Zinc(II) and Lead(II) during Electrodialysis

The processes of Zn2+ and Pb2+ extraction by bulk liquid membranes containing di (2-ethylhexyl) phosphoric acid and tri-n-octylamine during galvanostatic electrodialysis accompanied by electrodeposition of the metals were studied. The effects of the current density as well as of composition of the liquid membranes and aqueous solutions on the rate of zinc (II) and lead (II) transport were determined. It was demonstrated that a practically complete removal of zinc (II) and more than 90 % extraction of lead (II) from the feed solutions containing 0.01 M ZnSO4 or 0.01 M Pb (NO3)2 was achieved during 1.0 − 5.0 h of electrodialysis. A possibility of effective transfer of zinc (II) into dilute solutions of sulphuric, hydrochloric, perchloric and acetic acids was shown. Adherent zinc and lead coatings with a fine-grained structure have been deposited on the platinum cathode. More than 75% of zinc (II) and about 60% of lead (II) was deposited from solutions of sulfuric acid and perchloric acid, respectively.