| A static adsorption experiment was conducted to investigate influence of equilibrium time,initial concentration,pH value,and cation species on adsorption of two kinds of quinolone antibiotics (norfloxacin and ciprofloxacin) to kaolin.Results showed that the adsorption process of norfloxacin and ciprofloxacin followed pseudo-second-order kinetic equation,with adsorption rate of 0.021 kg/(mg·h)and 0.156 kg/(mg·h) respectively.Norfloxacin and ciprofloxacin can be divided into the initial fast adsorption stage and the slow adsorption stage; Adsorption isotherms of norfloxacin and ciprofloxacin to kaolin were well described by both Freundlich equation and Langmuir equation,with the adsorption capacity (lgKf) of 2.026 and 2.273 respectively,and the maximum adsorption (Qm) of 135.14 and 142.86 mg/kg respectively; The maximum adsorption of norfloxacin and ciprofloxacin to kaolin can be obtained when the pH value was 5,followed by pH value from 6 to 8; The influence of different cations on norfloxacin and ciprofloxacin adsorption to kaolin varied greatly,the higher valence the more influence; Adsorption of norfloxacin and ciprofloxacin to kaolin decreased with the increase of Ca2+ concentration,decreasing from 92.07 mg/kg to 58.12 mg/kg for norfloxacin,and from 96.71 mg/kg to 58.85 mg·kg-1 for ciprofloxacin when Ca2+ concentration decreased from 0.01 mg/L to 0.1mg/L.The results provided with a treatment approach for antibiotics containing wastewater. |
