Abstract:
Biochars produced from biomass residues have been recognized as effective sorbents to
hydrophobic compounds, but knowledge on sorption of antibiotics to biochar and its
mechanisms are still inadequate. Sorption of oxytetracycline (OTC) in aqueous solution to
maize-straw-derived biochar, and the effect of pH and metal ions, was investigated in batch
experiments, and the main sorption mechanisms were elucidated using FTIR and zeta
potential measurements. The results showed that sorption of OTC on biochar was highly pH-
dependant. The amount of sorbed OTC first increased and then decreased with increasing
pH, and maximum sorption was achieved at pH 5.5. Cu2+ enhanced the sorption of OTC,
while Pb2+ slightly reduced the sorption under acidic conditions. Other metal ions had no
significant effect on the sorption of OTC to biochar. Surface complexation, through π–π …