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2007
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February
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In the Laboratory
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A Pollutant Transformation Laboratory Exercise for Environmental Chemistry: The Reduction of Nitrobenzenes by Anaerobic Solutions of Humic Acid
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Frank M. Dunnivant and Mark-Cody Reynolds
Department of Chemistry, Whitman College, Walla Walla, WA 99362
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February 2007 Vol. 84 No. 2 p. 315
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| Abstract |
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This article presents a laboratory exercise for advanced undergraduate- or graduate-level environmental chemistry in which the student studies the chemical transformation (reduction) of substituted nitrobenzenes by natural organic matter under anaerobic conditions. The exercise uses a reference humic acid (Fluka) prepared in a standardized way yielding reproducible experimental conditions (pH, EH, etc.) and results that allow easy adoption in the teaching laboratory. Instead of focusing on a simple chemical concept, as might be common in lower-level laboratories, this exercise combines multiple concepts such as solution preparation, pH buffers, EH buffers, organic reaction mechanisms, reaction kinetics, and instrumental analysis. Data showing the dependence of the reaction on experimental parameters such as solution pH, solution EH, concentration of bulk electron donors (sulfide), concentration of natural organic matter (the electron mediator), and nitrobenzene substituent are presented. In addition, three journal articles are recommended to tie this laboratory exercise to the lecture portion of an environmental chemistry class.
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| Supplement |
List of the material and supplies, instructions for solution preparation, instrument conditions, and detailed procedures for the basic and advanced experiments are available.
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| More Information |
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Citation |
Dunnivant, Frank M.; Reynolds, Mark-Cody. J. Chem. Educ. 2007 84 315.
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Keywords |
Environmental Chemistry; Laboratory Instruction
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History |
Created:
Last Updated: |
1/9/2007
2/16/2007
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Caution!  | | Experiments, laboratory exercises, lecture demonstrations, and other descriptions of the use of chemicals, apparatus, instruments, computers, and computer interfaces are presented in the Journal of Chemical Education as illustrative of new or improved ideas or concepts in chemistry instruction and are directed at qualified teachers. Although every effort is made to assure and encourage safe practices and safe use of chemicals, the Journal of Chemical Education cannot assume responsibility for uses made of its published materials. Many chemicals are hazardous. Precautions for the safe use of hazardous chemicals and directions for their proper disposal are described in the Material Safety Data Sheets and on the labels. We strongly urge all those planning to use materials from our pages to make choices and to develop procedures for laboratory and classroom safety in accordance with local needs and situations. |
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| Home > JCE Print > Journal of Chemical Education > Issues >
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February
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