Feasible H₂S Sensing in Water with a Printed Amperometric Microsensor

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Growing concerns about pollution necessitate advanced wastewater treatment systems.
• Hydrogen sulfide (H2S) is a toxic gas prevalent in industrial and urban effluents, requiring constant monitoring.
• Existing monitoring methods often lack the speed, durability, or cost-effectiveness needed for real-time wastewater analysis.

Purpose of the Study:

• To develop a fast, durable, and economical electrochemical sensor for on-line hydrogen sulfide (H2S) detection.
• To utilize digital printing for reproducible fabrication of miniaturized H2S sensors.
• To enhance sensor performance through material modification for complex matrix analysis.

Main Methods:

• Fabrication of a 2 mm² graphite electrode modified with single-walled carbon nanotubes (SWCNTs), poly(vinyl alcohol), poly(diallyl dimethylammonium chloride), and polylactic acid (PLA) using digital printing.
• Characterization of the electrochemical sensor's performance, including optimal pH range, limit of detection, and stability.
• Testing the sensor's efficacy in complex matrices for H2S contamination detection.

Main Results:

• The digitally printed microsensor demonstrated high sensitivity and reduced sulfur poisoning due to SWCNTs.
• Incorporation of PLA improved the sensor's mechanical stability and overall electrochemical performance.
• An optimal working pH range of 7.5-11.0 was identified, with a limit of detection as low as 4.3 μM.
• The sensor proved capable of operating effectively in complex matrices for H2S detection.

Conclusions:

• Digital printing offers a viable method for mass-producing cost-effective and reproducible electrochemical H2S sensors.
• The developed SWCNT-modified microsensor provides a promising analytical tool for real-time monitoring of H2S in wastewater treatment.
• This technology contributes to improved environmental monitoring and pollution control strategies.