Treatment of dairy wastewaters by electrocoagulation using mild steel electrodes

The removal of COD and oil-grease from dairy wastewater was experimentally investigated using direct current (DC) electrocoagulation (EC). In the EC of dairy wastewater, the effects of initial pH, electrolysis time, initial concentration of COD, conductivity and current density were examined. The COD and oil-grease in the aqueous phase were effectively removed when iron was used as sacrificial anode. The optimum operating range for each operating variable was experimentally determined. The batch experimental results revealed that COD and oil-grease in aqueous phase was effectively removed. The overall COD and oil-grease removal efficiencies reached 98 and 99%, respectively. The optimum current density, pH and electrolysis time for 18,300 mg COD/L and 4570 mg oil-grease/L were 0.6 mA/cm2, 7 and 1 min, respectively. Mean energy consumption was 0.003 kWh/kg of COD.     

A novel two‐part interconnector for solid oxide fuel cells

A two‐part interconnector is developed for solid oxide fuel cell stacks to reduce cost and to improve sealing. The novel interconnector involves a metallic core for current collection and gas distribution and a ceramic support to house the metallic core and to separate two short stacks. The new interconnector reduces usage of expensive metallic alloys and substantially reduce mismatch between stack components due to higher expansion coefficient of metals. The new interconnectors also improve sealing with glass–ceramics eliminating chromium evaporation which is a major reason for sealing failure in fully metallic interconnectors. A proof of concept short stack is manufactured and tested in this study. A comparable performance with a convectional interconnector is obtained with new interconnector, while substantially improving the sealing quality. Copyright © 2014 John Wiley & Sons, Ltd.     

Investigation of the electro-oxidation of artificial Black Sea water using cyclic voltammetry on metal sulfide electrodes (I)

Black Seawater is an alternative hydrogen source because it has hydrogen sulfide content. Seawater electrolysis is a promising method to produce hydrogen. The anodic oxidation of hydrogen sulfide is a novel approach for directly generating electricity via fuel cells. Therefore, four materials (Cu, Stainless Steel 304 (SS), V₂O₅ and Ni) were examined in artificial seawater containing hydrogen sulfide (HS⁻). We developed active metal sulfide electrodes for oxidizing HS⁻. Alongside the corrosion potentials, the progression of the oxidation and reduction reactions was obtained by the cyclic voltammetry method. The active behaviors of the metal sulfide (MS_x) layers were determined by applying Electrochemical Impedance Spectroscopy (EIS). Although the Cu₂S electrode acts as the active catalyst during HS⁻ ion oxidation, NiS is the most suitable metal sulfide because it exhibits a higher corrosion resistance than Cu₂S. While V₂O₅ demonstrates catalytic activity at high temperatures (≥30 °C), FeS layers corrode easily in the artificial seawater environment.