Activated Carbon Adsorption Of Quinolone Antibiotics In Water

Quinolone antibiotics(QNs)have been widely used all over the world.The application in medical and breeding industry without restriction has led to universal antibiotic remnants in natural water environments.In this paper,F-400 activated carbon was ground to powder and used to investigate adsorption of QNs.As basic technical support,HPLC-MS/MS method for QNs detecting and Solid Phase Extraction(SPE)method for QNs preconcentration were established.QNs preconcentrated by SPE could reach limit of detection(LOD)as 0.1 ng/L.For adsorption kinetics,adsorption equilibrium can be reached at 40 h.The first 6-8 h made over 70%,16-24 h made over 90%of total adsorption capacity.Four kinetic models were introduced for kinetics fitting,Pseudo second-order model had better fitting coefficient(r~2>0.97),indicated a complicated microprocess in adsorption kinetics.Six pH conditions were chosen to conduct isotherm experiments.Adsorption capacity is highest at neutral solution,followed by acidic and alkaline condition.QNs may change electric charge at diverse pH conditions,which influents PAC adsorption.Hydrophobic effect and electrostatic interaction were inferred as main mechanism for adsorption.Maximum adsorption capacity of 4 QNs is related to molecular weight and hydrophobicity of each QN.Trace level adsorption isotherms of 4 QNs was analyzed by linear fitting.Fitting results confirmed a chemical adsorption process of QNs by F-400 PAC,Chemical Adsorption Potential(CAP)is related to the density of?-electron at aromatic ring in QN molecule.Physical Adsorption Potential(PAP)is related to molecular hydrophobicity.Natural Organic Matter may hinder adsorption by integrating QNs and filling PAC pores,it can be removed by coagulating process.Two or more QNs adsorbed by PAC simultaneously obeyed parallel adsorbing process at low concentration.When concentration raises,adsorbate with higher PAP obtained higher adsorption capacity.For practical application,PAC is evaluated as an effective and controllable technology for QNs removing,which deserves further applicatory research.