Defect-engineered carbon-based materials as electron donor or acceptor for preferential removal of diverse emerging contaminants of opposite electronic nature

Sp 3 -type edge defects and sp 2 -type pentagonal defects were precisely engineered. • EDC prefers electron-donating ECs, while PDC favors electron-accepting ones. • π-π EDA interactions dominate the selective adsorption of ECs. • Defect configuration governs electronic matching for selective ECs removal. The persistent release of emerging contaminants (ECs) into water systems poses significant risks to human health and ecosystems. Adsorption using carbon-based materials offers a sustainable remediation strategy, yet the role of intrinsic defects in preferential contaminant removal remains poorly understood. Herein, we engineered two carbon-based materials with distinct defect configurations: one enriched with sp 3 -type edge defects (EDC) and another with sp 2 -type pentagonal ring defects (PDC), as unequivocally corroborated by aberration-corrected scanning transmission electron microscopy (ac-STEM) and complementary characterizations. Batch adsorption experiments were conducted using six ECs of opposite electronic nature, including antibiotics, DNA bases, and nanoscale plastics. Remarkably, PDC exhibited superior adsorption capacities for electron-accepting contaminants with values of 392.5 mg g −1 for norfloxacin, 249.1 mg g −1 for cytosine, and 115.3 mg g −1 for PS-COOH, while EDC showed superior adsorption capacities for electron-donating ones with values of 469.5 mg g −1 for amoxicillin, 230.5 mg g −1 for adenine, and 129.5 mg g −1 for PS-OH. Mechanistic studies, combining preferential desorption and density functional theory calculations, revealed that π-π electron donor-acceptor interactions, governed by the distinct HOMO/LUMO energies of the defects, dominate the adsorption process. Biomass-derived counterparts exhibited consistent preferential adsorption, confirming that the defect-engineering approach yields similar trends across the tested precursors. This suggests a potentially extendable strategy and offers an electronic-matching paradigm for the preferential removal of diverse ECs based on their intrinsic electronic properties. Download: Download high-res image (380KB) Download: Download full-size image