Electrocatalytic detection and adsorptive removal of rose bengal dye from wastewater

Abstract A novel nanomaterial-based strategy is introduced that serves a dual purpose: the detection and removal of a hazardous dye Rose Bengal (RB) from wastewater. This approach aligns with the critical objective of promoting sustainable water management. Zinc oxide nanoparticles doped with 4% Fe (Fe–ZnO NPs), synthesized via a sol–gel method and characterized by UV–Vis, XRD, and FTIR, were integrated with multi-walled carbon nanotubes (MWCNTs) to modify a glassy carbon electrode, forming an electrochemical nanosensor for RB detection. The sensor demonstrated excellent sensitivity, selectivity, and reproducibility, achieving a detection limit as low as 70 pM under optimized conditions (10 s deposition time, 0 V deposition potential, and 0.2 M NaOH as the electrolyte). Electrochemical impedance spectroscopy confirmed efficient charge transport on the sensing platform. For dye removal, BiOCl NPs exhibited high adsorption efficiency, removing up to 95.5% of RB within 360 min at pH 5.4, with a maximum adsorption capacity (qm) of 37.73 mg/g. The adsorption followed Langmuir isotherm behavior at low concentrations and Freundlich behavior at higher concentrations, with kinetics conforming to a pseudo-second-order model. This work highlights the integrated use of nanomaterials for simultaneous monitoring and remediation of dye pollutants, offering a cost-effective and environmentally friendly strategy for wastewater treatment.