Fe³⁺ ion quantification with reusable bioinspired nanopores

Excessive Fe³⁺ ion concentrations in wastewater pose a long-standing threat to human health. Achieving low-cost, high-efficiency quantification of Fe³⁺ ion concentration in unknown solutions can guide environmental management decisions and optimize water treatment processes. In this study, by leveraging the rapid, real-time detection capabilities of nanopores and the specific chemical binding affinity of tannic acid to Fe³⁺, a linear relationship between the ion current and Fe³⁺ ion concentration was established. Utilizing this linear relationship, quantification of Fe³⁺ ion concentration in unknown solutions was achieved. Furthermore, ethylenediaminetetraacetic acid disodium salt was employed to displace Fe³⁺ from the nanopores, allowing them to be restored to their initial conditions and reused for Fe³⁺ ion quantification. The reusable bioinspired nanopores remain functional over 330 days of storage. This recycling capability and the long-term stability of the nanopores contribute to a significant reduction in costs. This study provides a strategy for the quantification of unknown Fe³⁺ concentration using nanopores, with potential applications in environmental assessment, health monitoring, and so forth.