Semester of Graduation

Summer 2021

Degree

Master of Science (MS)

Department

Chemistry

Document Type

Thesis

Abstract

Hexavalent chromium Cr(VI), a form of chromium mainly generated through industrial processes, has attracted great research interests due to its severe toxicity to biological systems. A common way to remove hexavalent chromium from industrial wastes is through reduction to the non-toxic trivalent state. To this end, methods such as chemical reduction, chemical precipitation and coagulation have been used. However, these methods are limited by poor removal efficiency, formation of secondary pollutants (sludge), and are mostly applicable to aqueous solutions. Recently, electrochemical methods have been investigated for reducing hexavalent chromium, but there is a lack of data on the reduction of hexavalent chromium in nonaqueous media. This is a challenge considering the possibility of Cr(VI)-contaminated nonaqueous industrial wastes ending up in water bodies. Therefore, it is crucial to develop methods of treating such wastes before disposal. In this research, an electrochemical method that involves the use of a nonaqueous solvent is presented. Using glassy carbon electrodes and acetonitrile-based electrolyte, a reproducible method of collecting data was established. With the aim of achieving an energy-efficient reduction and making the reduction process electrocatalytic, the effect of Brønsted acids on the reduction process was investigated. In addition, the process of finding suitable electrocatalysts was initiated. Results obtained show reproducible response of glassy carbon electrodes toward hexavalent chromium in acetonitrile and that Cr(VI) reduction proceeds via proton-coupled electron transfer processes.

Committee Chair

Elgrishi, Noemie

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