Electrochemical regeneration of catechol-fouled graphene: A theoretical and experimental study

Electrochemical regeneration has attracted considerable attention as a sustainable alternative to conventional thermal and chemical regeneration methods for restoring the adsorption performance of carbon-based adsorbents. However, the molecular mechanisms governing contaminant desorption and their relationship to experimentally achievable regeneration performance remain poorly understood. In this study, we combined MD simulations, umbrella-sampling-based potential of mean force calculations, DFT, and experiments to establish a multiscale framework for understanding and validating electrochemical regeneration of catechol-contaminated carbons. MD simulations revealed that catechol desorption is strongly governed by surface chemistry, hydration structure, and electric-field direction. DFT analysis further revealed that surface oxidation induces localized charge redistribution and polarization-driven adsorption channels that enhance catechol retention on GO surfaces. These molecular-level predictions were experimentally validated using graphene-, GO-, and reduced GO-modified electrodes. Quantitative adsorption–desorption analysis showed that GO exhibited the highest catechol adsorption capacity, whereas graphene achieved the highest electrochemical regeneration efficiency (87.96 ± 10.67%). Adsorption isotherm, kinetic, Raman, XPS, and LC–MS analyses consistently supported the simulation-derived retention and desorption trends. Furthermore, the graphene platform maintained approximately 69.6% of its initial adsorption capacity after five regeneration cycles and demonstrated low regeneration-energy consumption (0.206 ± 0.016 kWh kg⁻¹-catechol recovered), while remaining effective under varying pH, ionic-strength, competitive-organic, and realistic water conditions. By directly linking atomistic desorption mechanisms with experimentally validated regeneration performance, this study provides a mechanistic foundation for the rational design of electrochemically regenerable carbon adsorbents and establishes a transferable strategy for the removal and regeneration of strongly adsorbed phenolic contaminants in water-treatment systems.