Wireless, Accurate and Long-term Nitrogen Monitoring in Wastewater by Solid-State Ion-Selective Membrane (S-ISM) Sensors

摘要

In the 21st century, a pivotal requirement for treating wastewater is the availability of low-cost, real-time in situ, accurate and long-term water quality monitoring. This study develops state-of-the-art wireless solid-state, ion-selective membrane (WS-ISM) sensors targeting nitrogen contaminants including ammonium and nitrate in wastewater. The mm-sized S-ISM sensors were made by precisely embedding liquid-state ionophore in a well-crafted matrix consisting of Polyvinyl chloride (PVC) and plasticizers for enhanced adhesion to the electrode surface. The S-ISM sensors were then couple to a wireless gateway as a WS-ISM prototype and examined in continuous-flow rigorous field tests using municipal wastewater for 7 days. Test results indicated that the WS-ISM nitrogen sensors possessed excellent accuracy and precision, high selectivity, and multi-day stability. In summary, the compact mm-sized WS-ISM nitrogen sensing technology developed in this study enables an unprecedented accuracy and durability for continuous wastewater monitoring, and thus pose a great potential toward data-driven wastewater infrastructure.