Date of Award

Summer 1997

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry & Biochemistry

Program/Concentration

Chemistry

Committee Director

Frank E. Scully, Jr.

Committee Member

Robert L. Ake

Committee Member

Edward J. Poziomek

Call Number for Print

Special Collections LD4331.C45 L83

Abstract

Bisulfite is commonly used to dechlorinate chlorinated municipal wastewater. However, several studies suggest that bisulfite is not effective in dechlorinating N-chlorinated amino components of wastewater. The purpose of this study was to investigate the effectiveness of an alternate dechlorinating agent, caroate (peroxysulfate), and to compare its rate of dechlorination of three different types of chloramines with that of bisulfite.

Four N-chlorinated amino compounds were investigated: N-chlorodiethylamine, N­ chloroalanylphenylalanine, N-chloroglycylphenylalanine, and N-[2-(N'-chloroimino)­ propanoyl]phenylalanine. These compounds were selected from different families of N­ chloramines to study the effect of structure on dechlorination by both caroate and bisulfite. At pH 7.0 and at 23 °C, caroate dechlorinated N-chlorodiethylamine, N-chloro­ alanylphenylalanine, N-chloroglycylphenylalanine, and N-[2-(N'-chloroimino)propanoyl]­ phenylalanine with the calculated second order rate constants of 27.7 (±0.96) M-1min-1, 2.61 (±0.01) M-1, 1.31(±0.09) M-1min-1, and 7.1 (±0.25) x 10-2M-1 min-1 respectively. Under the same conditions, the second order rate constants for the dechlorination of the same compounds by compounds by bisulfite were found to be 1.63 (±0.14) x I0'M-1 min-1, 1.86 (±0.09) x 103 M-1 min-1, 2.12 (±0.13) x 103 M-1min-1,7.8 (±1.5) x 1D2 M-1min-1, respectively using HPLC. When using amperometric titration at the same pH and temperature, the second order rate constants for these compounds were found to be 1.29 (±0.17) x 105 M·1 min·', 2.37 (±0.19) x 103 M· 1min•1, 2.01 (±0.11) x 103 M"1min·1, and 8.5 (±0.07) x 102 M·' min·', respectively.

In conclusion, caroate was found to be a very slow dechlorinating agent compared to bisulfite and it is not fast enough to replace bisulfite in the dechlorination of wastewater in treatment plants. Furthermore, the N-chloroketimines compared to the simple N-chloramines and N-chlorodipeptides studied was slowly dechlorinated by bisulfite. As a result it is likely that N-chloroketimines contribute to the pool of total residual chlorine compounds which are poorly reduced in the dechlorination of wastewater effluents by bisulfite.

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DOI

10.25777/a1yg-yy78

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