عنوان مقاله [English]
Cefazolin is a widely used antibiotic in the treatment of bacterial infections that enters the water sources in original or metabolized form through the discharge of sewage and effluents. The presence of antibiotics in the environment can affect non-target pathogens, change the structure, enrich the algae in water sources, interfere with photosynthesis in plants and cause morphological abnormalities in plants. Various methods have been studied to remove antibiotics. Among these, surface adsorption is one of the appropriate methods. Therefore, in this study, the synthesis of polyaniline-polyethylene glycol resin and its evaluation in the removal of cefazolin by the adsorption process were investigated. Polyanyylene-polyethylene glycol resin was prepared by chemical polymerization method. Transfer electron microscope, thermometer and infrared spectrometer were used to determine the properties of the synthesized resin. In this study, the effect of pH parameters in the range of 2 to 8, the amount of adsorbent 0.1 to 5 g, the initial concentration of antibiotics in the amount of 10 to 100 mg/L, contact time 15 to 120 minutes and the temperature range of 20 to 70 °C, adsorbent desorption with nitric acid and sodium hydroxide, the interfering compounds of chloride and sulfate were investigated. The adsorption isotherms of Langmuir, Freundlich, Tamkin and adsorption kinetics were determined. In all stages, spectrophotometer was used to determine the concentration of cefazolin and HPLC was used to determine the effect of interfering ions on the removal of cefazolin and to confirm the results of spectra to determine the effect of interfering ions. The contact time of 60 minutes of adsorbent and cefazolin was selected as the optimal time due to the completion of the adsorption capacity of polyaniline-polyethylene glycol resin and high removal efficiency. Due to the high removal efficiency of cefazolin at (pH = 5), cefazolin was selected as the optimal pH due to the competition between OH- ions and negatively charged molecules. Adsorbent (3 g) was selected as the optimal adsorbent due to the increase in removal efficiency with increasing adsorbent consumption and the presence of a large number of adsorption sites. Elimination of cefazolin was tested in the concentration range (10, 20, 50, 70 and 100 mg/L) and the results showed that with increasing the concentration of cefazolin, the removal efficiency decreased from 69% to 50% due to more adsorption sites on the adsorbent surface in concentrations. Low concentration of cefazolin causes to be rapidly absorbed and the removal efficiency increases. The results of experiments of the effect of disturbing compounds showed that the removal percentage of cefazolin in distilled water from 98.46% to 72.72% in municipal water despite the disturbing compounds of chloride and sulfate due to the formation of anions with the adsorbent surface and the formation of stable complexes and barriers to cefazolin uptake decreased. The results of adsorbent reduction showed that the percentage of removal of cefazolin after 6 steps by nitric acid decreased from 93.99 to 74.55% and decreased by profit from 41.25 to 21.56%.