Date of Submission

6-2019

Document Type

Thesis

Degree Name

Master of Science in Environmental Engineering

Department

Civil Engineering

Advisor

Emese Hadnagy

Committee Member

Stanley Menacherry

Committee Member

Agamemnon Koutsospyros

LCSH

Atrazine, Herbicides--Environmental aspects, Dechlorination

Abstract

Atrazine is one of the most common herbicides used in the United States, contaminating ground and surface water, and when used for drinking water poses a threat to human health. An innovative technology to alleviate atrazine contamination in drinking water is treatment with a bimetallic reagent that is comprised of a base metal (typically Mg or Fe) and a catalytic metal (for example Pd). Atrazine has chlorine bond which increases its persistence in the environment. This research studied the potency of a Mg/Pd bimetallic system to dechlorinate atrazine in water. Experiments were carried out to determine the impact of reagent dose, base metal to catalyst ratio, temperature, and initial pH adjustment on the reaction in order to obtain the optimum conditions for dechlorination. Results indicate that Mg/Pd is highly effective in reducing atrazine; 99% of atrazine was degraded in 30 min when using a 0.5% solid to liquid (S/L) ratio (the dose). The main degradation product formed was dechlorinated atrazine (almost 100%). When the reagent dose was reduced, the removal efficiency also decreased. In general, as the catalyst amount was reduced for a given reagent dose, longer reaction times were required to achieve the same level of removal. Complete degradation of atrazine occurred in the first 5 min when the temperature of the reaction solution was increased to 45ºC (compared to 20 ºC at 0.5% S/L). The activation energy of atrazine dechlorination in the presence of Mg/Pd was calculated to be 81.8 KJ/mol. Finally, lowering the initial pH of the reaction solution from 9 – approximately 3 or 4 resulted in increased removal efficiencies. Overall, results show that the Mg/Pd bimetallic system is a promising technology for the treatment of atrazine residues in water.

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