Bismuth extracted by environment-friendly aqueous two-phase system from secondary sources applied in the development of an alternative bismuth film electrode for the simultaneous determination of cadmium and lead at water and food samples

Abstract

The reuse of materials for the development of high-performance electrochemical sensors is explored in this work. Specifically, bismuth (Bi) films were electrodeposited using Bi extracted by an aqueous two-phase system (ATPS) from discarded fusible plugs (BiSn alloy), which are used as safety valves in gas cylinders. The ATPS is an environmentally friendly strategy for liquid-liquid extraction, and its suitability for obtaining purified Bi for use in electrochemistry is demonstrated. As a proof-of-concept, the bismuth film electrodes obtained from extracted Bi (BiATPS-FE) were applied at the simultaneous voltammetric determination of heavy metal species (Cd2+ and Pb2+). By applying square-wave anodic stripping voltammetry (SWASV), the BiATPS-FE displayed a similar voltammetric response toward both the analytes compared to bismuth film electrodes prepared from standard Bi precursors (Bi-STD). Under optimized conditions, the BiATPS-FE sensor exhibited linear ranges of 0.50 to 7.0 µmol L−1 and 0.40 to 5.0 µmol L−1 for Cd2+ and Pb2+, respectively, with limits of detection of 0.044 µmol L−1 (Cd2+) and 0.019 µmol L−1 (Pb2+). The developed voltammetric method, adopting BiATPS-FE, was successfully applied to lake water and tea drink samples for the simultaneous determination of Cd2+ and Pb2+, with recovery percentages ranging from 93% to 100%. Furthermore, the proposed sensor (BiATPS-FE) showed good repeatability and reproducibility. The exciting analytical performance verified for the Bi-film electrodes emphasizes the feasibility of combining environmentally friendly materials recovery and electrochemistry strategies to propose value-added electrochemical sensors.