Impedance Sensor for Real-Time Ammonium Detection Based on MWCNT/ZnO Nanocomposites

Area of Science:

• Environmental Science
• Materials Science
• Sensor Technology

Background:

• Aqueous ammonium (NH4+) is a critical water quality parameter.
• Accurate and real-time monitoring of NH4+ is essential for environmental protection and resource management.
• Existing monitoring methods can be complex, time-consuming, or lack field applicability.

Purpose of the Study:

• To develop a novel impedance sensor for real-time, field-specific monitoring of aqueous ammonium (NH4+).
• To fabricate and characterize a sensing element using a hybrid nanocomposite for enhanced performance.
• To integrate the sensor with an IoT system for continuous data transmission and remote access.

Main Methods:

• Fabrication of screen-printed interdigitated electrodes (IDEs) modified with a Multi-Wall Carbon Nanotube (MWCNT) and Zinc Oxide (ZnO) nanocrystal hybrid nanocomposite.
• Characterization of the sensor's impedance response to varying ammonium concentrations.
• Testing the sensor's selectivity against common interfering cations (Fe2+, Ni2+, K+, P+).
• Integration of the sensor with an IoT-enabled NodeMCU microcontroller for real-time data acquisition and transmission via web applications.

Main Results:

• The developed NH4+ sensor demonstrated a sensitivity of 67.13 Ω /mM with average correlation coefficients of 0.80.
• The sensor's impedance magnitude remained unaffected by the presence of Fe2+, Ni2+, K+, and P+ interfering cations, indicating high selectivity.
• Successful interfacing with an IoT-enabled NodeMCU microcontroller enabled continuous monitoring and real-time data reporting.
• The integrated system allows for remote user access to real-time NH4+ levels through web applications.

Conclusions:

• A robust and selective impedance sensor for aqueous ammonium (NH4+) has been successfully developed.
• The hybrid MWCNT/ZnO nanocomposite offers a promising sensing material for electrochemical applications.
• The IoT-enabled system provides a direct, real-time, and field-deployable solution for continuous water quality monitoring.
• This technology has significant potential for environmental monitoring and water resource management applications.