Oxidation-controlled graphene oxide for adsorptive removal of neutral and ionic micropollutants: Experimental characterization and predictive modeling

초록

Graphene oxide (GO) is increasingly applied as an adsorbent and as a functional component in composite materials, making it essential to understand how its adsorption properties of raw GO vary with its oxidation level and the structure of the target substances. In this study, GO flakes with controlled oxidation levels were synthesized and systematically characterized. The sample with the highest adsorption performance was selected for detailed evaluation against 54 micropollutants, including neutral, cationic, and anionic species, across varying concentrations. Kinetic and isotherm experiments confirmed the broad adsorption capacity of optimized GO flakes. Compared with commercial granular activated carbon, GO showed markedly higher adsorption toward cationic pollutants, while its performance for anionic and neutral compounds was comparable or slightly lower. Mechanistic insights and predictive capability were gained by developing a quantitative structure-activity relationship (QSAR) model based on a linear free energy relationship framework. This model incorporated molecular activity degree as a key parameter and successfully predicted adsorption partitioning coefficients with high accuracy (R2 = 0.86, validated at R2 = 0.88). The integration of experimental characterization with predictive modeling provides a practical tool for guiding the rational design of GO-based systems in environmental remediation and advanced water treatment.

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