Development and evaluation of a sugarcane bagasse biochar electrode for sensing and anodic oxidation of organic pollutants in soft drink industry wastewater

Abstract

Biochar derived from sugarcane bagasse was engineered and evaluated as a low-cost electrochemical material for glucose detection and for the anodic oxidation of soft drink industry wastewater. The material was modified with nickel species to enhance its redox activity and catalytic behavior. In the first part of the study, the nickel-modified biochar electrode was characterized electrochemically to assess its performance as a glucose sensor in alkaline media. Chronoamperometric measurements at 0.6 V in 0.1 M KOH revealed a linear detection range from 0.1 to 1.0 g/L, a sensitivity of 1.0843 mA·g/L, and a limit of detection of 0.18 g/L (1.021 mM). The electrode exhibited stable, reproducible responses across multiple additions and replicates, confirming its suitability for high-concentration glucose environments typical of beverage production residues. In the second part, the electrode was applied to the anodic oxidation of wastewater simulating soft drink industry effluents. Electrolysis experiments conducted at 5-7 V achieved 80–100% removal of organic carbon, as confirmed by TOC analyses and supported by an increase in inorganic carbon, demonstrating substantial mineralization. Chronoamperometric comparison with boron-doped diamond (BDD) showed that while BDD displayed rising current associated with hydroxyl radical generation, the NiO-modified biochar electrode exhibited a decreasing current profile attributed to Ni²⁺/Ni³⁺ mediation yet retained high degradation performance. Additional studies on voltage and current density revealed a direct dependence of removal efficiency on the applied electrochemical load (R² ≈ 0.99). The combined results indicate that nickel-modified biochar electrodes are an effective, sustainable, and economical alternative for both sensing and advanced oxidation processes in high-strength industrial wastewater. Their performance, derived from low-cost biomass waste, highlights their potential for scalable implementation.