| The research took the three different kinds of wastewater treatment process of Haikou as the research object, and took the2kinds of quinolones (ofloxacin, ciprofloxacin) and4kinds of sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfamethoxazole) antibiotics used more in the hospital as the detection object, and established a method for determination of the above6kinds of antibiotics in hospital wastewater. Through detecting the content of the antibiotics in each unit of the hospital wastewater treatment to evaluate the removal effect of the current hospital wastewater treatment. The research also studied the adsorption effect of the activated carbon, kaolin and macroporous resin to the6kinds of antibiotics, and investigated the effects of pH value, temperature, reaction time, dosage on the adsorption. The main conclusions are as follows:1. A solid phase extraction-high performance liquid chromatography (SPE-HPLC) method has been established for simultaneous determination of6kinds of typical antibiotics in the hospital wastewater. According to the optimization result of the chromatographic conditions (detector wavelength, column temperature, mobile phase buffer, buffer concentration, flow rate of mobile phase) and the eluent (species, ratio),It identified when the detector wavelength was285nm, column temperature was30℃, mobile phase was0.1%formic acid solution, the flow rate of mobile phase was1mL/min, the eluent was pure methanol, the correlation coefficient of the6antibiotics regression equation was more than0.99, and the linear range was among0.01μg/L to50.0μg/L while the linear relationship was well. As to the6antibiotics, the limit of detection (LOD) was1.42～6.15ng/L, and the limit of quantitation (LOQ) was4.12～18.54ng/L,while the instrument detection limit (IDL) was0.138～0.278μg/L, and the instrument quantity limit (IQL) was0.462～0.904μg/L. It also showed that the recovery of the6antibiotics was75.4%～94.3%, and the correlation coefficients was4.2%～7.5%(n=5).2. The results of the6antibiotics removed by the current hospital wastewater treatment process and each unit link were as fellows.(1) The treatment capacity of the6antibiotics by existing hospital wastewater treatment process was between10.8%to100%. There was a trend that the removal capacity of wastewater treatment process was’anaerobic pondâ†'aerobic pondâ†'sedimentation tankâ†'chlorination’>’aeration tankâ†'sedimentation tankâ†'chlorination’>’septic tankâ†'chlorination’.(2) The removal rate of sulfadiazine and sulfamethoxazole by the process of ’anaerobic pondâ†'aerobic pondâ†'sedimentation tankâ†'chlorination’ reached to100%, the removal rate of ofloxacin, ciprofloxacin and precipitation were92.5%,95.5%and45.5%, respectively. The removal rate of sulfamerazine by the process of’aeration tankâ†'sedimentation tankâ†'chlorination’ reached to100%, the removal rate of ofloxacin, ciprofloxacin and sulfamethoxazole were59.5%,10.8%and52.4%, respectively. The removal rate of sulfamerazine and sulfamethoxazole by the process of’septic tankâ†'chlorination’reached to100%, the removal rate of ofloxacin, ciprofloxacin, sulfadiazine and sulfamethazine were97.6%,74.6%,58.7%,51.5%, respectively.(3) The anaerobic pond had poor removal effect on sulfadiazine while had better removal effect on sulfadiazine. The removal rate of ciprofloxacin, sulfamerazine, sulfamethazine, sulfamethoxazole and ofloxacin by the aerobic pond were75.9%,62.3%,77.3%,69.6%and13.9%,respectively.The removal effect of chlorination on the sulfamethazine was poor but on the sulfamethoxazole was well, and the chlorination can make the other4antibiotics removed above50%. The aeration tank had little removal effect on the6antibiotics, because the sediment can release some antibiotics into the water.3. The experiment results of the6antibiotics adsorbed by the activated carbon, kaolin and macroporous resin were as fellows.(1) The adsorption of the6antibiotics by the activated carbon was affected by the initial pH value, temperature, reaction time and the amount of activated carbon. When the pH value was5.5, the activated carbon had the best adsorption effect on the6antibiotics. When the pH value was smaller than5.5, the adsorption effect got up with the increased of the pH value, but when the pH value is bigger than5.5, the adsorption effect decreased with the increased of the pH value. The adsorption effect of pH on ofloxacin and ciprofloxacin by the activated carbon was less than the effect on the other4sulfonamide antibiotics. Under the condition of room temperature, the activated carbon had the better adsorption effect on the6antibiotics, the higher the temperature, the more the active carbon was not conducive to adsorb the antibiotics. The adsorption effect of the active carbon to the antibiotic had experienced three stages, the adsorption was faster before the first30min, then slowly, and130min later, the adsorption got to equilibrium. The dosage of activated carbon had obvious effect on the antibiotic. When the optimum pH was5.5, the optimum temperature was28℃, the dosage of the activated carbon was0.02g, the activated carbon can adsorb the all antibiotics in130min.(2) The kaolin made different adsorption effect on the6antibiotics because of the different species of the antibiotics, compared to the sulfonamide antibiotics, the quinolones antibiotics can be absorbed easier by the kaolin. The adsorption effect of kaolin to2quinolones antibiotics was more influenced by the pH value, temperature, reaction time and the dosage. When the pH value was5.5, the kaolin had the best adsorption effect on the2quinolones antibiotics, and the higher the temperature, the adsorption rate decreased. The adsorption was faster before the first5min, then took adsorption and desorption continuously,130min later, the adsorption got to equilibrium. When the dosage of kaolin was1.0g, the adsorption rate of ofloxacin and ciprofloxacin were both99.9%, the adsorption effect was quite good. The adsorption of kaolin to4sulfonamide antibiotics was less affected by the pH value, temperature, reaction time and dosage, and the adsorption capacity was limited, even when the dosage of kaolin was1.0g, the2quinolone antibiotics were basically absorbed completely, the adsorption rate of4sulfonamide antibiotics remained lowly, the adsorption rate was less than40%.(3) The adsorption of macroporous resins to6antibiotics was not influenced consistently by the pH value, temperature, reaction time and the resin dosage. The pH value had greater effect on the adsorption rate of macroporous resin to quinolone antibiotics, under the condition of pH=9.5, the adsorption rate reached the maximum value, at the same time, The pH value can influence the adsorption of macroporous resins to sulfamethoxazole. When the pH value was5.5, the adsorption rate reached the maximum. In addition, The pH value had little effect on the adsorption of macroporous resins to other3sulfonamide antibiotics, the adsorption rate were not vary with the changed of pH value. The temperature had little effect on the adsorption of macroporous resins to ofloxacin, sulfadiazine and sulfamerazine, but the temperature had great effect on the adsorption of macroporous resins to ciprofloxacin, sulfamethazine and sulfamethoxazole, and the adsorption effect decreased with the increased of temperature, and with the increased of temperature, the adsorption rate decreased. With the time fly, the adsorption of macroporous resins to ofloxacin, ciprofloxacin and sulfamethoxazole took adsorption and desorption continuously, but the adsorption to the other3sulfonamide antibiotics was maintained, the adsorption got to equilibrium after30min. With the increased of the macroporous resins dosage, the adsorption of macroporous resins to6antibiotics had little increased, the adsorption effect was not ideal.(4) Through the effect of the6antibiotics adsorbed by the activated carbon, kaolin and macroporous resin, it was concluded that the active carbon was the ideal adsorbent, which can adsorb the all6antibiotics at a low dosage. |
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