Dunnivant, Frank M. 4 0
A pollutant transformation laboratory exercise for environmental chemistry. 6 6 - - - - - - - - . - . - 0 . - . - 0 .
ABSTRACT : 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.
5
5
2 = =
2
2 --0------
6 --0-- 2 --------
0 2 --
--20------
Environmental chemistry.;Chemistry - Study and teaching.;Chemical laboratories.;Reduction (Chemistry).;Nitrobenzene.;Humic acid. --------20--
--------20--
----2
QD1 .J826ce / 2
/ 2
/
/
A pollutant transformation laboratory exercise for environmental chemistry. 6 6 - - - - - - - - . - . - 0 . - . - 0 .
ABSTRACT : 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.
5
5
2 = =
2
2 --0------
6 --0-- 2 --------
0 2 --
--20------
Environmental chemistry.;Chemistry - Study and teaching.;Chemical laboratories.;Reduction (Chemistry).;Nitrobenzene.;Humic acid. --------20--
--------20--
----2
QD1 .J826ce / 2
/ 2
/
/