Reduction of substituted nitrobenzenes by anaerobic solutions of humic acid

CHED 207

Patrick David Ford, fordpd04@hendrix.edu and M. Warfield Teague, teague@hendrix.edu. Department of Chemistry, Hendrix College, 1600 Washington Avenue, Box 3255, Conway, AR 72032
Pollutant mitigation is important in determining the life cycle toxicity of a compound. This is pertinent because of the intentional design of pesticides to rapidly degrade and not accumulate in the environment. Humic substances occur in all soils, waters, and sediments of the ecosphere arising from degradation of plant and animal tissue. Humic acid can assist sulfide reduction of nitro groups to amines, transforming some pollutants to less harmful forms. In this study, a series of humic acid concentrations were prepared, mimicking the limit of naturally occurring humic acid concentrations. A bulk electron donor initially reduces the functional group on the pollutant which then reduces the pollutant from a nitro substituent to an amine substituent. The rate-order dependence of the nitro reduction was monitored using gas chromatography, and the reduction rates were compared to the humic acid concentrations present in each sample.