Microwave Sensors for In Situ Monitoring of Trace Metals in Polluted Water

Abstract

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors’ best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

Recent Progress in Micro- and Nanotechnology-Enabled Sensors for Biomedical and Environmental Challenges

“…On the other hand, in the environmental realm, these waves find applications in remote sensing, pollution monitoring, and climate research, as well as the identification and analysis of specific chemical compounds and environmental pollution detection [ 116 , 117 ]. Frau et al developed a novel technique using microwave spectroscopy and planar sensors for the real-time in situ monitoring of water quality, specifically targeting trace metals in polluted mining areas, and demonstrated the immediate response and classification of water pollution levels based on multiple resonant peaks in the GHz range, which represents a significant advancement in quantifying pollutants in water [ 116 ].…”

Low-Cost Internet-of-Things Water-Quality Monitoring System for Rural Areas

“…Another solution based on UAC and IoT for monitoring livestock was presented by Behjati et al [19]. Microwave sensors were used by Frau et al [20] to detect trace metals in polluted mining area waters. The authors described a novel technique making use of both microwave spectroscopy and planar sensors to monitor the water quality in real time.…”

Non-destructive erosive wear monitoring of multi-layer coatings using AI-enabled differential split ring resonator based system

“…Among the various classes of microwave resonator sensors, split ring resonators (SRRs) are particularly interesting due to their planar structure, ease of fabrication, passive operation, and conformability on various surfaces. SRRs have previously been used for chemical 19 – 21 and biological applications 22 – 26 , material characterization 27 , 28 , and corrosion monitoring 29 – 31 . They have also been used for real-time sensing applications including ultra-violet light detection 32 , ice sensing 33 , 34 , and gas sensing 35 .…”