Symposium 5 Electrochemical Engineering & Technology 57th Annual Meeting of the International Society of Electrochemistry S5·KN-1 Development and Scale up of the FFC Cambridge Process I.R Buckingham1, S.J. Brewer1, A. Fones1, D.J. Fray2, D.R. Hodgson*1, D. Jackson1, L. Slevin1, S.E. Male1 1 Metalysis Ltd, Unit 2 Farfield Park, Wath upon Dearne, Rotherham, S63 5DB, UK Keynote 2 Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK *[email protected] The FFC Cambridge Process was discovered in 1997 at the University of Cambridge. The process is very elegant and environmentally friendly in that an oxide is made the cathode in a bath of a molten chloride of a very electropositive element. Under these Symposium 5 - conditions, the favoured cathodic reaction is the ionisation of the oxygen in the oxide to from oxygen ions that dissolve in the salt. The final result is a finely divided metal product. Metalysis Ltd has a world-wide exclusive license to exploit the technology for all materials containing less than 40% titanium. The process starts with a metal oxide powder that is formed into a mechnically stable, porous pellet. A collection of pellets is made the cathode in a bath of molten salt (typically CaCl2) and reduction of the oxide occurs under potential control. The process has wide applicability and a number of materials have been produced in kg quantities. This paper will describe the basics of the process, illustrate how the process is being scaled and will discuss the nature of a range of metals produced to date. Electrochemical Engineering & Technology S5·KN-2 57th Annual Meeting of the International Society of Electrochemistry Electrodeposition of nanomaterials in air and water stable ionic liquids S. Zein El Abedin and F. Endres* Keynote Faculty of Natural and Materials Sciences, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld, Germany. [email protected] [email protected] Ionic liquids, especially air and water stable, have attracted considerable attention Symposium 5 - since they have extraordinary physical properties superior to those of water or organic solvents. They have extremely large electrochemical windows, more than five volts, and hence they give access to elements which cannot be electrodeposited from aqueous solutions such as, e.g., Al, Mg, Ta, Ge and Si. Moreover, the problems associated with hydrogen ions in conventional protic solvents can be eliminated in ionic liquids because ionic liquids are normally aprotic. In this paper, we report on the electrodeposition of tantalum on different substrates such as, single crystalline gold Au(111), polycrystalline platinum, NiTi alloy and stainless steel in the water and air stable ionic liquid 1-butyl-1-methyl-pyrrolidinium bis (tri-fluoromethylsulfonyl) imide ([BMP]Tf2N) containing TaF5 as a source of tantalum. The results show that, in addition to the formation of insoluble compounds, Ta can be electrodeposited in the o ionic liquid ([BMP]Tf2N) containing 0.5 M TaF5 at 200 C. The XRD patterns of the electrodeposit show the characteristic patterns of crystalline tantalum. Moreover, it was found that the deposition of an only 500 nm thick film of Ta on NiTi alloy improves its corrosion resistance which, in turn, enhances its biocompatibility. We report also the first results of the electrodeposition of nano- and microcrystalline aluminium in some water and air stable ionic liquids namely, 1-butyl-1-methylpyrrolidinium bis(tr ifluoromethylsulfonyl) imide [BMP]Tf2N, 1-ethyl-3-methylimidazolium bis(trifluoro methylsulfonyl) imide [EMIm] Tf2N and trihexyl-tetradecyl phosphonium bis(trifluo Electrochemical Engineering & Technology romethylsulfonyl) imide (P14,6,6,6 Tf2N). 57th Annual Meeting of the International Society of Electrochemistry S5·KN-3 Electrochemical oxidation of synthetic dyes Marco Panizza*, Rico Ricotti and Giacomo Cerisola Dipartimento di Ingegneria Chimica e di Processo “G.B. Bonino”, Università degli Studi di Genova, p.le J.F. Kennedy 1 – 16129 Genova, Italy. Keynote *[email protected] The textile and paper industries require large volumes of water and produce effluents that contain large quantities of organic compounds and inorganic salts and have high COD and colour levels. In particular, due to the presence of reactive dyes, colour removal is the major problem in dealing with these effluents. In fact, synthetic dyes contain one or more functional groups and complex aromatic structures which make Symposium 5 - them very difficult to biodegrade. Commonly employed methods for colour removal are adsorption, coagulation, chemical oxidation with ozone or Fenton’s reagent and advanced oxidation processes; however these processes are quite expensive and have operational problems. For these reasons there has been increasing interest in the use of new methods such as electrochemical oxidation. Many studies have been carried out on electrochemical treatment of organic compounds and several anode materials have been tested; however several of these have demonstrated a rapid decline in activity due to surface fouling (glassy carbon, and others have performed only selective oxidation of pollutants without obtaining their complete incineration (Ti/IrO2, Pt). The complete mineralisation of the organics to CO2 has only been obtained using high oxygen overvoltage anodes such as SnO2, PbO2 and boron-doped diamond because during electrolysis at high potentials these electrodes produce hydroxyl radicals from the water discharge on their surfaces. Among these electrodes BDD anodes exhibit good chemical and electrochemical stability even in strong aggressive media, a long life and a wide potential window for water discharge, and are thus promising anodes for industrial-scale wastewater treatment. The aim of this work was to study the electrochemical oxidation of a model wastewaters containing dyes with different structures: aniline blue (C32H25N3O9S3Na2) Electrochemical Engineering & Technology a triarylmethane dye, or alizarin red (C14H7O7SNa) an anthraquinone dye. The influence of the main operating parameters, such as current density, flow-rate and temperature, affecting COD and colour removal was investigated in order to find the optimum experimental conditions. The results of the electrolysis revealed the suitability of the electrochemical process for completely removing the COD and effectively decolourising the wastewaters due to the production of hydroxyl radicals on the diamond surface. In particular, the oxidation was favoured by a low temperature, a low current density and a high flow- rate meaning that the oxidation was a diffusion-controlled process. S5·KN-4 57th Annual Meeting of the International Society of Electrochemistry Electroreduction of polychloroethanes at silver electrodes Alessandro Minguzzi, Sandra Rondinini, Alberto Vertova* Keynote The University of Milan, Department of Physical Chemistry and Electrochemistry, Milan, Italy *[email protected] Recent studies [1-2] on the electroreduction of volatile organic halides on Ag cathodes have highlighted the role of silver as powerful electrocatalyst for the hydrodehalogenation of volatile organic halides, namely polychloro-methanes and Symposium 5 - –ethanes, in non-aqueous and mixed solvents. The extended cyclic voltammetry experiments on both C1 and C2 derivatives, together with the preparative electrolyses performed on model compounds (CHCl3 and CH2Cl2), not only confirm that significant energy saving can be achieved by the use of silver as electrode material, as in all the other electroreductions of organic halides investigated so far, but also suggest that the reaction pathway(s) might once again differ from the one observed on less active materials, as in the case of glassy carbon. In the present work the investigations have been focussed on polychloro-ethanes and extended from non-aqueous to pure aqueous media to confirm the applicability of the degradation procedure to any H2O-organic solvent composition, up to 100% H2O. The results point to a preferential pathway toward the total hydrodehalogenation of the substrates Acknowledgments. The financial support of the University of Milan (FIRST) and of EC Programme Improving Human Research Potential and the Socio- economic Knowledge Base - IHP contract number HPMT-CT-2001-00314 is gratefully acknowledged. 1. 1. S. Rondinini, A. Vertova, Electrochim. Acta, 2004, 49, 4035 2. G. Fiori, S. Rondinini, G. Sello, A. Vertova, M. Cirja, L. Conti, J. Appl. Electrochem. Electrochemical Engineering & Technology 2005, 35, 363. 57th Annual Meeting of the International Society of Electrochemistry S5·KN-5 Electrochemical mass transfer modelling of a complex two phase heat transfer problem: case of a prototype slagging gasifier Keynote A.A. Wragg1*, N.P. Simpson1, M.A. Patrick1, J. Kalcikova2, J. Krysa2 1 Department of Engineering, University of Exeter, Exeter, EX4 4QF, UK 2 Department of Inorganic Technology, VSCHT , Technicka 5, 166 28 Prague 6, Czech Republic *[email protected] This paper describes the modelling of heat transfer in the hearth of a prototype slagging gasifier using the electrochemical limiting diffusion current technique and subsequent application of the Chilton-Colburn analogy between heat and mass transfer. The apparatus used was based on a quarter scale model of the Symposium 5 - British Gas Westfield gasifier and was manufactured in the form of a large conical vessel with top diameter of 0.61 m fabricated from nickel sheet. The half angle at