Graphene-modified pencil graphite bismuth-film electrodes for the determination of heavy metals in water samples using anodic stripping voltammetry
| dc.contributor.advisor | Jahed, N. | |
| dc.contributor.advisor | Iwuoha, Emmanuel | |
| dc.contributor.author | Pokpas, Keagan William | |
| dc.date.accessioned | 2016-03-29T13:13:00Z | |
| dc.date.accessioned | 2024-05-09T10:50:36Z | |
| dc.date.available | 2016-03-29T13:13:00Z | |
| dc.date.available | 2024-05-09T10:50:36Z | |
| dc.date.issued | 2013 | |
| dc.description | >Magister Scientiae - MSc | en_US |
| dc.description.abstract | Electrochemical platforms were developed based on pencil graphite electrodes (PGEs) modified with electrochemically deposited graphene (EG) sheets and Nafion-graphene (NG) nanocomposites in conjunction with an in situ plated bismuth-film (EG-PG-BiE and NG-PG-BiE). The EG- and NG-PG-BiEs were used as sensing platforms for determining Zn2+, Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV). EG sheets were deposited onto pencil graphite electrodes by cyclic voltammetric reduction from a graphene oxide (GO) solution, while a dip coating method was used to prepare the NG-PG-BiE. The GO and graphene, with flake thicknesses of 1.78 (2 sheets) and 2.10 nm (5 sheets) respectively, was characterized using FT-IR, HR-SEM, HR-TEM, AFM, XRD and Raman spectroscopy. Parameters influencing the electroanalytical response of the EG-PG-BiE and NG-PG-BiE such as, bismuth ion concentration, deposition potential, deposition time and rotation speed were investigated and optimized. The EG-PG-BiE gave well-defined, reproducible peaks with detection limits of 0.19 μg L-1, 0.09 μg L-1 and 0.12 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively, at a deposition time of 120 seconds. The NG-PG-BiE showed similar detection limits of 0.167 μg L-1, 0.098 μg L-1 and 0.125 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively. For real sample analysis, the enhanced voltammetric sensor proved to be suitable for the detection and quantitation of heavy metals below the US EPA prescribed drinking water standards of 5 mg L-1, 5 μg L-1 and 15 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively. | en_US |
| dc.identifier.uri | https://hdl.handle.net/10566/14538 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of the Western Cape | en_US |
| dc.rights.holder | University of the Western Cape | en_US |
| dc.subject | Heavy metal detection | en_US |
| dc.subject | Graphene | en_US |
| dc.subject | Bismuth-film | en_US |
| dc.subject | Trace metal analysis | en_US |
| dc.title | Graphene-modified pencil graphite bismuth-film electrodes for the determination of heavy metals in water samples using anodic stripping voltammetry | en_US |