Sustainable Rice Husk-derived Porous Carbon as an Electrode Modifier for Electrochemical Lead Detection

Abstract

Heavy metal contamination poses serious threats to public health and ecosystems, with lead (Pb-2(+)) being among the most hazardous owing to its persistence and toxicity. Rapid, cost-effective, and portable Pb-2(+) detection is therefore essential for environmental monitoring. In this study, rice husk-derived porous carbon (RHPC) was synthesized at three carbonization temperatures (350, 450, and 550 degrees C) and applied as a modifier for screen-printed electrodes (SPEs). RHPC suspensions were drop-cast on SPE surfaces and evaluated by square-wave anodic stripping voltammetry (SWASV). Structural characterization revealed increased porosity, higher surface area, and enhanced conductivity with rising carbonization temperature, with RHPC-550 showing the most favorable properties. Electrochemical measurements confirmed that RHPC-550-SPE achieved a markedly improved electrochemically active surface area (0.030 cm(2)) compared with the bare SPE (0.009 cm(2)). As a result, RHPC-550-SPE exhibited a higher sensitivity (0.037 mu A/mu g<middle dot>L--(1)), a lower detection limit (1.6 mu g/L vs. 6.2 mu g/L for bare SPE), and an excellent linearity (R-2 > 0.999) across 0-200 mu g/L. Furthermore, negligible interference from common ions was observed, confirming reliable selectivity. These findings demonstrate that RHPC-modified SPEs provide a sustainable and low-cost sensing platform for trace Pb-2(+) monitoring in environmental applications.