This is a SHORT, LIGHT and SIMPLE newsletter. Its purpose is to rekindle, in the initiated, terminology they have once learned and enlighten the uninitiated on terms they may have heard but never knew the meaning of.

Oxidation and Reduction aka Redox

When a substance combines with oxygen, it is “oxidized.” The dome in the picture is made of copper plates that have been exposed to atmospheric oxygen; the exposed exterior changed to copper oxide and turned green in the process.

Oxidized iron is red. We see it everywhere.

On the atomic level, when an element joins with oxygen, it loses electrons to the oxygen. Elemental oxygen is “electron-hungry” and certain elements do not hold strong to some of the electrons they natively posses. The oxygen snatches one or two electrons; however, the electron “donor” does not let go and the two elements get hooked in a tug-o-war.

We expand the concept and say that any time a substance loses electrons; it is “oxidized,” regardless of whether it lost the electrons to oxygen or to another element or compound.

For example, chlorine is a strong oxidizer. It reacts with many organic materials, and it reacts explosively with many metal powders. Chlorine easily pulls electrons off of many other chemicals in much the same way that oxygen does during burning. A lot of heat energy is released during the process. Sometimes the energy is released explosively.

Oxidation also results in the breaking up of complex compounds.  A common example is aerobic digestion of sanitary sewage: a breakdown of organic matter in liquid through the addition of oxygen or air.

Another, close-to-heart example is the cleanup of soil and groundwater that have been contaminated with petroleum products. Mother Nature has been doing it for ages but her speed of progress is too slow in relation to our needs. We accelerate the process through the injection of oxidizing chemicals.  The oxidation breaks down the complex petroleum molecules into harmless carbon dioxide and water.

Reduction is the reverse of oxidation. It is a reaction in which atoms or molecules either lose oxygen or gain hydrogen or electrons.

Oxidation and reduction always happen together: an oxidizer is being reduced and a reductant (reducing agent) is getting oxidized. In the bleaching of hair, the chlorine is reduced and the hair is oxidized.

The combination of chlorine with sodium gives us sodium chloride (table salt), where the chlorine is the oxidizer and sodium is the reductant.

Redox is an abbreviation of Reduction-Oxidation, which often occur together; these are reactions involving electron transfers; the reductant donates electrons to an oxidant. None survives alone (Law of Affinity). The oxidant needs a reductant, the reductant needs and oxidant. Applies also to life.
 

You can find past issues of "Environmental Enlightenment" at www.amiadini.com Wealth of information about environmental site assessments in the real estate transactions and issues concerning assessment and cleanup of contamination in the subsurface soil and groundwater.

Call me if you have any questions. There are no obligations.

Ami Adini
Ami Adini & Associates, Inc.
Environmental Consultants
Underground Storage Tank Experts
323-913-4073; 323-667-2336 fax
mail@amiadini.com
www.amiadini.com

Ami Adini is a mechanical engineer, California Registered Environmental Assessor, Level II, and president of AMI ADINI & ASSOCIATES, INC. (AA&A), an environmental consulting firm specializing in all phases of environmental site assessments, rehabilitation of contaminated sites and upgrading of underground storage tank facilities. AA&A specializes in practical solutions to environmental concerns using the highest standards of ethics and integrity while providing its clients with maximum return on their investments.