(103d) Enzymatic Generation of Hydrogen Peroxide and Gluconic Acid Chelate for Chloro-Organic Destruction by Modified Fenton Reaction

Glucose oxidase is a well-known enzyme that catalyzes the oxidation of glucose to produce gluconic acid and hydrogen peroxide. Fenton reaction is a powerful oxidation technology used for the dechlorination of groundwater pollutants. For the application of Fenton reaction in in-situ remediation, successful operation of Fenton reaction near neutral pH is essential. Hence, Fenton reaction is carried out in the presence of chelates so that they can sequester ferrous and ferric ions, making the operation of Fenton reaction near neutral pH possible. The focus of this study was to couple the glucose oxidation reaction with chelate-based Fenton reaction. The idea was to use the hydrogen peroxide and chelate gluconic acid generated during glucose oxidation for the dechlorination of 2,4,6-trichlorophenol (TCP) by Fenton reaction. The oxidation of glucose was carried out using the enzyme in free and immobilized forms. Both random and site-directed techniques were used for the immobilization of glucose oxidase. The rate of production of hydrogen peroxide was determined for each system, and was used to estimate the time required for complete consumption of glucose during the process, thus minimizing the presence of glucose in the Fenton reaction. Separation of the enzyme was achieved before initiating the Fenton reaction. The Fenton reaction was carried out at varying ratios of gluconic acid/Fe(II) and under different pH conditions, and their effect on the decomposition of TCP and H2O2 was observed. Depending on the reagent (H2O2, chelate, and Fe(II)) concentrations one can obtain dechlorination > 99%. This research is supported by NIEHS-SBRP. The corresponding author of this paper is D. Bhattacharyya (db@engr.uky.edu).