title: Effects of pH and metal ions on oxytetracycline sorption to maize-straw-derived biochar.
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. Cu(2+) enhanced the sorption of OTC, while Pb(2+) 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 interaction and metal bridging, was the most important sorption mechanism although cation exchange might have played a role.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
authors.forename: Mingyun
authors.initials: M
authors.lastname: Jia
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Yongrong
authors.initials: Y
authors.lastname: Bian
authors.forename: Xin
authors.initials: X
authors.lastname: Jin
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Fredrick Orori
authors.initials: FO
authors.lastname: Kengara
authors.forename: Renkou
authors.initials: R
authors.lastname: Xu
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
mesh_terms: D000327:Adsorption / Q000187:drug effects; D001673:Biodegradation, Environmental / Q000187:drug effects; D002606:Charcoal / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007477:Ions; D007700:Kinetics; D008670:Metals / Q000494:pharmacology*; D009994:Osmolar Concentration; D010118:Oxytetracycline / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D014866:Waste Products; D003313:Zea mays / Q000737:chemistry*
chemical_list: D007477:Ions; D008670:Metals; D014866:Waste Products; C540010:biochar; D002606:Charcoal; D010118:Oxytetracycline