Preparation of high-performance polymer sensitive membrane for rapid and sensitive detection of ammonium ions in aqueous solution

Abstract

Polymer sensitive membrane is a key component of the ammonium ion selective electrode (ISE). Developing a high-performance ammonium ion polymer sensitive membrane can promote production and application of the electrode, reducing costs and simplifying ammonia nitrogen detection. In this study, we modified the surface of the ammonium ion selective membrane and synthesized a low-cost antimicrobial material by anchoring the broad-spectrum antimicrobial agent, silver nanoparticles (AgNPs), on the surface of two-dimensional transition metal car- bides (Ti₃C₂Tx MXene). This material can be used as a carrier to avoid the release of AgNPs. The inorganic antimicrobial agent AgNPs@MXene was adhered to the surface of the ammonium ion-selective membrane by polydopamine, forming an antimicrobial coating. The modified ammonium ion-selective electrode had a rapid response time of 12 s, with an average response time of 12.4 s. After repeated tests, a lower detection limit of 5.89 × 10⁻⁷ (10^−6.23) mol/L was achieved in ammonium chloride solution. These results indicate that the ammonium ion monitoring electrode we prepared can effectively monitor ammonia nitrogen concentration in sewage and wastewater over a long period of time. This also enhances the service life of the ammonium ISE and reduces maintenance costs for the sensor.