Sub-surface H2S detection by a Surface Acoustic Wave passive wireless sensor interrogated with a ground penetrating radar

TL;DR

This paper presents a passive wireless surface acoustic wave sensor system for detecting subsurface H2S using ground penetrating radar, enhanced by a moisture-sensitive polymer coating for improved sensitivity.

Contribution

Development of a novel passive SAW sensor coated with a lead(II)-containing polymer for selective H2S detection in moist underground environments using GPR.

Findings

Signal enhancement via water absorption increases sensitivity.

Polymer coating provides selectivity for H2S detection.

Sensor effectively detects H2S in moist subsurface conditions.

Abstract

Long-term monitoring of organic pollutants in the soil is a major environmental challenge. We propose to meet this issue by the development of a polymer dedicated to selectively react with H2S, coating surface acoustic wave transducers designed as passive cooperative targets with the compound, and probing their response using Ground Penetrating RADAR, thus providing the capability to monitor the presence of H2S in the subsurface environment. The selectivity is brought by including lead(II) cation in a reticulated polymer matrix which can be deposited as a thin layer on a surface acoustic wave sensor. We demonstrate a signal enhancement mechanism in which water absorption magnifies the signal detection, making the sensor most sensitive to H2S in an underground environment saturated with moisture.