Microwave and Functional Materials: A Novel Strategy for Detecting Toxic Metals in Polluted Freshwater

• Main Author: Frau, Ilaria
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2020
• Subjects: Adsorption; Analytical chemistry; Cables; Chemistry; Computer science; Hydration; Information Technology; Metals; Mining; Optics; Polymer chemistry; Polymers; Reproducibility; Sensors; Smartphones; Software; Spectrum analysis
• ISBN: 9798374427554

Worldwide, thousands of pollutants threaten freshwater and environmental health. Therefore, toxic metals from point and diffuse sources in abandoned mining areas need to be efficiently managed and monitored.As of yet, no method can measure toxic metals in water, in situ and in real-time, guaranteeing a clear picture of water quality continuously. Microwave spectroscopy has been shown to give a real-time response dependent on the sample composition as soon as a water sample interacts with the electromagnetic waves.Consequently, this work aims to specialise microwave sensors to monitor toxic metals in mining-impacted water. Planar microwave sensors have been integrated with mixtures of materials (such as metal oxides and chelating polymers) using screen-printing technology. These novel sensing structures are defined as functionalised electromagnetic sensors (f-EM sensors). F-EM sensors, compared with uncoated sensors, were able to qualify with higher sensitivity and selectivity toxic metals (Zn and Cu) in simple lab-prepared solutions at various concentrations.F-EM sensors were then adapted to directly probe water samples and tested in the laboratory with collected freshwater samples using the standard addition method. Data were analysed using a novel approach based on multiple peak analysis at selected frequencies. Subsequently, f-EM sensors were tested in situ in mining-impacted water in four polluted mining areas in the UK. The results were compared and the possibility to qualify and differentiate in situ polluted water was assessed.In conclusion, a combination of various f-EM sensors, defined as an f-EM sensor array, is a valuable solution for monitoring and managing contaminated freshwater resources, by providing practical, rapid, in situ and low-cost measurements for evaluating unexpected variations in water composition.