Research Information System
Microchemical Journal, vol.220, 2026 (SCI-Expanded, Scopus)
This study presents the synthesis and electrochemical evaluation of chemically activated carbon (AC) derived from waste wheat biomass, as well as its application in electroanalytical sensing. The AC was prepared via a two-step carbonisation process, followed by FeCl3 modification, yielding a graphite-like structure with high porosity and conductivity. The obtained Fe-modified AC was used to fabricate a carbon paste electrode (CPE) for potentiometric and voltammetric analyses. Comprehensive characterisation (BET, XRD, FTIR, Raman spectroscopy, SEM-EDX, and TEM) confirmed the structural and surface properties of the synthesised material. Electrochemical measurements demonstrated a linear response over the concentration range of 1.0·10−6–1.0·10−1 mol·L-1, with a near-Nernstian slope of 54.35 mV·decade−1 and a response time of up to 20 s. Cyclic voltammetry (electrode's response to ferricyanide in potassium chloride solution) revealed a single anodic peak at approximately +340 mV (vs Ag/AgCl), attributed to the Fe2+ → Fe3+ oxidation, confirming the irreversible nature of the redox process and the stability of the electrode surface during repeated cycling. Based on this electrochemical performance of CPE recorded for the Fe3+-containing solution as an analyte and the anodic current at approximately 620 mV (vs Ag/AgCl), which increases as the scan rate rises, it has been suggested that the sensing mechanism of CPE is most likely based on a predominantly diffusion-controlled one-electron transfer process (Fe2+/Fe3+). A comparative study showed that the CPE achieved a low relative error of 0.775 % in redox titration (H2O2 with KMnO4). In comparison, a higher error of 15.25 % was obtained in complexometric titration (Fe3+ with EDTA), emphasising its superior performance in redox-based systems. Kinetic analysis of the redox titration revealed rapid electron transfer and a consistent current response, further validating the electrode's electrochemical reliability. Additionally, the use of agricultural waste and paraffin binder aligns with green chemistry principles, underscoring the sustainability of the proposed approach. Overall, the Fe-modified AC-based CPE offers a cost-effective, eco-friendly, and high-performance platform for electroanalytical applications, particularly in redox titration, kinetic studies, and environmental monitoring.