چكيده به لاتين
In this study, facile and cost-effective modification methods, including alkali treatment and acid treatment, were evaluated to improve the adsorption capacity of NaY zeolite for diclofenac sodium elimination. The performance of unmodified NaY, sodium hydroxide treated zeolite, hydrochloric acid treated zeolite, and sulfuric acid treated zeolite was compared, followed by optimization of sulfuric acid concentration since sulfuric acid was recognized as the preferred modifying agent and concentration of 0.1 M was obtained as the optimized point. Modification of NaY zeolite with sulfuric acid with a concentration of 0.1 M increased adsorption capacity from 23.07 mg/g to 69.23 mg/g. Analyses of FE-SEM, EDS, FTIR, BET and XRD were used to determine the characteristics of NaY and treated zeolites. According to the results of EDS analysis, the Si/Al ratio is 1.9014 for NaY, and the ratio reached 1.9633, 2.0218, and 2.250 after sodium hydroxide, hydrochloric acid, and sulfuric acid treatment, respectively. The effect of major factors on the diclofenac sodium adsorption process, including adsorbent dosage, contact time, solution pH, and initial concentration of diclofenac sodium were investigated and optimized in detail. The maximum adsorption capacity was obtained at a pH of 11. From the results of kinetic studies, the Elovich model has better agreement with experimental data, suggesting that the adsorbent surface is energetically heterogeneous and chemisorption leads the diclofenac sodium uptake onto the adsorbent. In accordance with the equilibrium modelling results, the Sips isotherm better expresses the diclofenac sodium adsorption mechanism onto the surface of the modified zeolite. According to the Langmuir isotherm model, the maximum adsorption capacity obtained for 0.2 g/L of treated zeolite was 117.77 mg/g. Eventually, sulfuric acid treatment was found as an effective and facile method for enhancing zeolite performance in DFS removal from aqueous solution.
