Probing waste-derived chars for the simultaneous determination of cadmium and lead ions

This research investigates the feasibility of utilizing waste-derived materials for the simultaneous electrochemical detection of cadmium (II) and lead (II) through differential pulse anodic stripping voltammetry (DPASV). Diverse chars were synthesized from distinct waste precursors, each chosen for its specific chemical characteristics. Waste tires were selected due to their elevated carbon content, shrimp-derived chitosan was chosen for its stable nitrogen content, while lemon peels, alkali lignin, and citrus pectin were included for their oxygen-rich composition. Chemical and structural analyses, such as CHN elemental composition, SEM-EDS analysis, infrared spectroscopy, electrochemical characterization, and contact angle measurements, showed that the properties of the chars were very different from each other. Electrochemical studies showed that these chars were useful in measuring Cd and Pb ions at micromolar concentrations under optimal conditions. The differences in performance were due to changes in the chemistry of the char surface. Of all the materials tested, WT-char was the best choice for making Nafion/GCE systems. It had well-separated peaks at-0.73 and-0.48 V vs. Ag/AgCl and low detection limits of 0.027 mu M for Cd(II) (2-50 mu M) and 0.0069 mu M for Pb(II) (2-8 mu M). The effective use of WT-char-Nafion/GCE in a real sample analysis also showed that it may be used to detect heavy metals in the environment. In contrast to hybrid biochar-nanomaterial sensors requiring complex fabrication, the proposed pristine waste char approach emphasizes simplicity and sustainability, offering a practical balance between cost, scalability, and analytical performance. This study highlights the potential of waste-derived materials as sustainable and economical solutions for environmental monitoring, underscoring the essential importance of feedstock selection and surface functionalization in maximizing electrochemical performance.