Achieving anodic stripping voltammetric detection of aluminum via Zn-assisted g-C₃N₄-modified sensor system

Due to its natural presence and extensive application in water treatment, aluminum ion (Al³⁺) contamination in water has become a pressing environmental challenge, necessitating the development of a facile yet sensitive analytical method. The current application of voltammetric detection of Al³⁺ has been limited to cathodic adsorptive stripping voltammetry, requiring a chelating agent for complexation. In this work, we proposed a zinc-assisted graphite carbon nitride-modified screen-printed carbon electrode method (Zn-assisted g-C₃N₄/SPCE) to carry out the anodic stripping voltammetry (ASV) detection of Al³⁺. By using zinc ions as a co-deposition species, we shifted the reductive potential of Al³⁺ to a less negative voltage (i.e., from -1.90 to -1.571 V), preventing severe hydrogen evolution during electrodeposition. Additionally, the g-C₃N₄ coating increases sensitivity by offering a substantial increase in Al³⁺ ion adsorption sites and regulating a more alleviated Al³⁺ nucleation process. The developed method has a detection limit of 8.9 ppb, excellent reproducibility, and strong resistance to interference. Field tests showed high consistency with the conventional atomic absorption spectroscopy method. The proposed method has excellent sensitivity and practicality and can be adapted to other metals that have the same technological issues when using ASV for quantitative detection.