Novel Material for Advanced Environmental Applications

Date of Award

8-2020

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

Dr. Ekkehard Sinn

Second Advisor

Dr. Yirong Mo

Third Advisor

Dr. David Huffman

Fourth Advisor

Dr. Sherine Obare

Keywords

Copper Sensor, FMN, PFOA, chlorinated solvents, MV

Abstract

This work is focused around synthesis and designing novel material for environmental application, centered in fundamental studies to identify materials that reduce common organic environmental pollutants and detect the toxic metals. Chapter 1 represents the overview of three widespread water contaminants: perfluoroalkyl substances, organohalides compounds, and and toxic metal ions. Due to continuous usage of these compounds as well as their toxicity, reliable and sensitive methods for their detection and degradation are urgently needed. Chapter 2 describes of molecular sensors designed with high sensitivity and selectivity to detect copper ion among many metal ions. These sensors provide dual optical, fluoro, and electrochemical signals for detection, which minimizes false-positives. The signal transduction occurs in real time with detection limits in the ppm range. Chapter 3 describes the reduction of perfluoroactanoic acid (PFOA). In this chapter, Flavin mononucleotide (FMN) was used as a catalyst to aid in the reduction process. FMN was attached to TiO2 nanoparticles, band gap irradiation was used to induce electron transfer from the TiO2 conduction band to FMN, thus yielding FMNH2. The FMNH2 generated in methanol on the TiO2 surface showed a high reductant efficiency toward PFOA. The products of the reduction process was analyzed using mass spectrometery and the results showed that more florine atoms were removed with increasing the temprature. This chapter reports that FMN is capable of storing and shuttling multiple electrons, which are desirable for potential applications including energy conversion. Also, to elucidate the mechanism of electrons transfer, we demonstrate the ability to photochemically modulate the reduction of FMN and we investigated its reactivity toward methyl viologen dichloride which acts as an electron acceptor. Chapter 4 describes the charge transfer between electron donating species (FMN) and methyl viologen (MV2+). The electron transfer from photochemically generated FMNH2 with MV2+ is monitored through absorption spectrometry. This charge transfer interaction results in the reduction of MV2+ to MV·+ as well as storage of electrons in MV+·. In Chapter 5, we report that FMN/TiO2 hybrid catalyst is effective toward the degradation of the following chlorinated solvents: carbon tetrachloride (CT), chloroform (CF), trichloroethylene (TCE), 1,2-dichloroethane (1,2-DA) and chlorobenzene (CB). The reactivity of the catalyst with the chlorinated compounds occurs at mild conditions in organic solvents.

Access Setting

Dissertation-Abstract Only

Restricted to Campus until

8-31-2030

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