Solvothermal reduction of graphene oxide for carbon paste electrode and its application in trace lead detection

• Main Author: Kok, Alvin Wei Jie
• Other Authors: Liu Erjia
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Nanotechnology
• Online Access: http://hdl.handle.net/10356/60871
• Institution: Nanyang Technological University

Industries’ failure to manage waste responsibly has led to contamination of water resources with heavy metals such as lead (Pb), cadmium and copper into the environment. These heavy metals have gained considerable interest as they can accumulate in the kidney, lung and liver, allowing sub-toxic exposure levels to pile up to toxic levels over time. Hence, fast detection of trace heavy metals in aqueous solution is essential to reduce fatal incidents that were caused by the consumption of polluted water. Hence, the objective of this project was to fabricate an enhanced carbon paste electrode (CPE) for detection of trace Pb. Reduced graphene oxide (r-GO) has drawn considerable interest because of its potential in applications such as electronic devices, circuits and sensors. This is primarily due to its similarity to pristine graphene which exhibits low resistivity, good chemical stability and high charge-carrier mobilities. Therefore, this project investigates the possibility of reducing graphene oxide (GO) under solvothermal reduction using ethylene glycol and constant heating of 270 °C. The reduced products were found to exhibit higher carbon atomic percentage ratio as compared to GO. In addition, the reduced products produce a higher ID/IG ratio than GO, which is a commonly reported behaviour of graphene oxide after chemical reduction in literatures. Square-wave anodic stripping voltammetry was utilised in this project to test the fabricated electrode’s capability in detecting trace Pb. The addition of r-GO to CPE indicates an enhancement as the modified CPE is able to detect Pb2+ at concentrations as low as 10-8 M.