Frau, I, Wylie, S, Byrne, PA, Cullen, J, Korostynska, O and Mason, A (2019) Functionalised microwave sensors for real-time monitoring of copper and zinc concentration in mining-impacted water. International Journal of Environmental Science and Technology, 17. pp. 1861-1876. ISSN 1735-1472

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Abstract

Microwave spectroscopy has been identified as a novel and inexpensive method for the monitoring of water pollutants. Integrating microwave sensors with developed coatings is a novel strategy to make the sensing system more specific for a target contaminant. This study describes the determination of copper and zinc concentration in water in both lab-prepared and acquired mine-water samples from two abandoned mining areas in Wales, UK. Uncoated sensors immersed in samples spiked with 1.25 mg/L concentrations of copper and zinc, using the standard addition method, were able to quantify the concentration at 0.44 GHz with a strong linear correlation (R2=0.99) for the reflection coefficient magnitude (|S11|). Functionalised microwave sensors with l-cysteine, chitosan and bismuth-zinc-cobalt oxide based coatings have shown improvement in the sensing performance. Specifically, the linear correlation at 0.91-1.00 GHz between |S11| and a polluted sample spiked with Cu showed a higher R2 (=0.98), sensitivity (1.65ΔdB/mg/L) and quality factor (135) compared with uncoated sensors (R2=0.88, sensitivity of 0.82 ΔdB/mg/L and Q-factor 30.7). A Lorentzian-peak fitting function was applied for performing advanced multiple peak analysis and identifying the changes in the resonant frequency peaks which are related to the change in metal ion content. This novel sensor platform offers the possibility of in situ monitoring of toxic metal concentrations in mining-impacted water and multiple peak features, such as area, full-width half maximum, centre, and height of the peaks have the possibility to offer higher specificity for similar toxic metals, as between copper and zinc ions.

Item Type:	Article
Uncontrolled Keywords:	planar electromagnetic sensors; coatings; standard addition method; chelating polymers; Lorentzian peak-curve fitting; heavy metals
Subjects:	T Technology > TD Environmental technology. Sanitary engineering T Technology > TN Mining engineering. Metallurgy
Divisions:	Civil Engineering (merged with Built Env 10 Aug 20)
Publisher:	Springer Verlag
Date Deposited:	13 Nov 2019 09:59
Last Modified:	13 Jan 2022 16:00
DOI or ID number:	10.1007/s13762-019-02588-w
Editors:	Abbaspour, M
URI:	https://researchonline.ljmu.ac.uk/id/eprint/11761

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