Removal of Antibiotics from Aqueous Solutions by a Carbon Adsorbent Derived from Protein-Waste-Doped Biomass

Antibiotic pollution in water is an urgent environmental problem. A novel carbon adsorbent derived from powdery puffed waterfowl feather (PPWF)-doped Phragmites australis (PA) was proposed for enhancing the removal of antibiotics from water in this study. Amoxicillin (AMX) and cephalexin (CEX) were selected as typical antibiotics. PPWF-doped (FPAC) and -undoped (PAC) carbon adsorbents were developed to test the adsorption capacities and mechanisms of AMX and CEX. Characterization techniques such as N₂ adsorption/desorption, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, elemental analysis, and Boehm titration were used to determine the properties of adsorbents. Results showed that more microporous structure and surface functional groups are exhibited in FPAC compared to PAC. The nitrogen-containing functional groups were introduced in FPAC. Adsorption capacities at different contact times, pH, and initial concentration were investigated by batch experiments. The AMX and CEX maximum adsorption capacities of FPAC are 25.2 and 30.1% higher than those of PAC, respectively. The kinetic data were well represented by the pseudo-second-order model for AMX and CEX adsorption. The equilibrium data agreed well with the Langmuir model for AMX adsorption and the Freundlich model for CEX adsorption. The adsorption mechanism of AMX and CEX was chemisorption, such as electrostatic attraction and covalent bonding.