Exceptional levofloxacin removal using biochar-derived porous carbon sheets: Mechanisms and density-functional-theory calculation

Fluoroquinolone antibiotic pollutants can irreversibly harm human health and aquatic organisms. Their removal remains an important challenge, because of the limited availability of practical adsorbents. Herein, we propose a porous carbon sheet (PCS-900) derived from waste biomass as a precursor for the decontamination of levofloxacin (LFC). Batch studies show that PCS-900 provided a high removal efficiency of 99.64% within 10 min, a maximum adsorption capacity of 754.12 mg/g, a wide applicable pH range, and a selectivity for LFC removal. The LFC can be sequestrated rapidly from different real water matrixes, indicating potentially practical application value. Micropore filling and π–π electron donor acceptor (EDA) interactions were responsible for the LFC removal mechanisms, which were confirmed by BET and FT-IR, Raman and theoretical calculation. BET analysis indicated a shrinking specific surface area and total pore volume. FT-IR and Raman spectroscopy showed a red shift of –OH stretching vibration and decreased intensity ratios of ID/IG after LFC adsorption, respectively. The theoretical simulation showed that various forms of LFC had strong interactions with the PCS-900. The closest interaction distance of LFC with PCS-900 was 2.52 Å via π–π stacking configurations. These findings could provide a reference for the fabrication of efficient antibiotic adsorbents from waste biomass in water remediation.