by Derek Pletcher

The need to protect the environment from further contamination by transition and heavy metal ions is well established and universally reinforced by legislation which sets limits on the levels in effluents which may be discharged into sewers and local waters. All chemical plants, factories and other facilities employing solutions of such metals should therefore be treating their wastewater before discharge. Electrochemical methods compete with a number of other technologies including evaporation, precipitation, ion exchange and solvent extraction to offer solutions to the needs of the many industries involved.

Electrochemical methods, however, are uniquely capable of recovering pure metal for recycle. Although electrochemical technology for metal ion removal has been available for some time [1-3], it continues to develop to meet the challenges of lower consent levels and more complex effluent compositions. Moreover, the technology now on the market is based on diverse electrochemical concepts.

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by Guillermo Daniel Zappi

New applications for fluorinated compounds are continuously being found. In areas such as agrochemicals, pharmaceuticals and fine chemicals, the enhanced activity of compounds in which one or more hydrogen atoms have been replaced by fluorine is the subject of a large body of research in universities and companies around the world.

It is estimated that between 40 and 45% of all new agrochemicals being developed contain fluorine. The physical, chemical and biological properties of chemical compounds, including boiling points, surface energies, polarity, acidity and reactivity can be greatly altered by substitution with one or more fluorine atoms.

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by Emory S. De Castro

Electrochemistry on gases originated in 1839 with Grove’s “gaseous voltaic battery”. Over 90 years later, Bacon built a demonstration fuel cell consisting of porous nickel electrodes. He is credited with creating a stable three phase reaction zone of electrode, gas, and electrolyte. Today’s fuel cell electrodes are far more sophisticated and lend themselves to other important electrochemical processes.

For example, the electrolytic production of pure hydrogen and oxygen is possible through an SPE® (solid polymer electrolyte) stack where DuPont’s Nafion® cation exchange membrane is the electrolyte. Other processes include gas purification, inorganic salt splitting (caustic from soda ash), or even synthetic applications (electrocatalytic oxidation of ethylene and methane). This review will show how the three-phase region of fuel cells can be exploited to create electrochemical gas sensors.

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