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 pi-pi electron donor acceptor (EDA) interactions were responsible for the LFC removal mechanisms, which were confirmed by BEF and FT-IR, Raman and theoretical calculation. BEF 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 I-D/I-G 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 angstrom via pi-pi stacking configurations. These findings could provide a reference for the fabrication of efficient antibiotic adsorbents from waste biomass in water remediation.