From agro-waste to advanced electrochemical interface: Selective detection of hydroquinone and catechol using sunflower-derived carbon

In this study, an ultrasensitive, cost-effective, and environmentally sustainable electrochemical sensor was developed using porous carbon derived from sunflower seed shells for the simultaneous detection of hydroquinone (HQ) and catechol (CC), two toxic phenolic pollutants frequently present in industrial effluents. The carbon material was synthesized through a direct, single-step pyrolysis process that required no chemical activation or metal additives, aligning with the principles of green chemistry and resource valorization. The structural and surface chemical properties of the carbon were comprehensively characterized using SEM, EDS, XRD, FTIR, and Raman spectroscopy. The presence of abundant oxygen-containing functional groups and naturally retained KCl contributed to the enhanced surface reactivity and electrical conductivity of the resulting carbons. The fabricated electrode exhibited excellent performance in simultaneously detecting HQ and CC, with distinct redox peak separation, high sensitivity, rapid response, and strong anti-interference capability. Under optimized conditions, the sensor achieved wide linear detection range of 0.5–400 μM for both analytes and ultralow detection limits of 3.24 nM for HQ and 1.95 nM for CC. The practical applicability of the sensor was validated using river and tap water samples, yielding recovery rates between 97.25 % and 106.42 %, which were in excellent agreement with high-performance liquid chromatography (HPLC) results. This work underscores the feasibility of converting agricultural waste into high-performance carbon-based sensing platforms for real-time environmental pollutant monitoring