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Dordanihaghighi, Sara

University of British Columbia

Rapid growth in industry and the improper disposal of pollutants have led to the contamination of the environment and humans’ food chains by heavy metal ions. The accumulation of heavy metal ions in living organisms results in lethal diseases such as cardiovascular diseases, heart failure, and cancer. Therefore, sensing and eliminating heavy metal ions have attracted researchers’ attention in recent years. Graphene Quantum Dots (GQDs) have emerged as one of the unique materials in fluorescence sensing of heavy metal ions due to their unique properties such as tunable bandgap, high solubility, large surface area, and absorptivity. In this work, novel amine-functionalized Graphene Quantum Dots (FGQDs) and nitrogen-doped Graphene Quantum Dots (DGQDs) were developed via a bottom-up chemical synthesis procedure. FGQDs and DGQDs were synthesized using citric acid as the carbon precursor and 3-aminobenzylamine as the surface modifier and dopant material. FGQDs and DGQDs were studied using different characterization techniques, including PL, FTIR, XPS, XRD, and TEM, to determine the fluorescence quenching of GQDs-based materials in the presence of heavy metal ions. The prepared nanostructures showed a uniform size of 5-6 nm, and a high content of amine groups and nitrogen doping. The FGQDs and DGQDs illustrate a quantum yield of 13.78% and 14.01%, respectively. The FGQDs showed an effective fluorescence quenching towards Fe³⁺ ions with a detection limit of 2.43 ppm with high selectivity and sensitivity among other heavy metal ions. On the other hand, the DGQDs samples showed effective fluorescence quenching towards Hg²⁺ ions with a detection limit of 1.99 ppm.

Text

2021-07-26

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/79106

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/