Mohammad Ansarizadeh; Tayebeh Tabatabaei; Mohammad Reza Samaei; Mostafa Leili; Mohammad Mehdi Baneshi
Abstract
Background: Discharging antibiotics into the environment could cause great concern for scientists. In the present study, tetracycline (TC) antibiotic was photodegraded with titanium dioxide (TiO2) and zinc oxide (ZnO) fixed on the polyurethane (PU) in the presence of ultraviolet (UV) irradiation and ...
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Background: Discharging antibiotics into the environment could cause great concern for scientists. In the present study, tetracycline (TC) antibiotic was photodegraded with titanium dioxide (TiO2) and zinc oxide (ZnO) fixed on the polyurethane (PU) in the presence of ultraviolet (UV) irradiation and optimized through response surface methodology (RSM).
Methods: This experimental study was conducted on the most effective variables (pH, contact time, TC concentration, and catalyst doses) for experimental design. The experiments of degradation with the process of PU/UV/nanocatalyst composite were conducted with a reactor glass vessel (1000 mL) as batch mode.
Results: The results showed that the quadratic model can be used for the interpretation of experiments. The results of the model represented that all parameters had a significant effect on the tetracycline removal, and the degradation of antibiotics was obtained at the optimum condition that was 95% for ZnO/UV/PU and 97% for TiO2/UV/PU. The main radical for the degradation of TC was hydroxyl ions based on the scavenger study and the first-order kinetic model was best fitted with data. The highest removal efficiency was obtained at pH of 5.2, catalyst dose of 2.64g/m2, TC concentration of 25.21, reaction time of 82 min using ZnO/UV/PU and pH of 5.8, catalyst dose of 2.9 g/m2, TC concentration of 25.12, and reaction time of 90 min using TiO2/UV/PU.
Conclusion: It could be concluded that the process of nanocatalyst fixed on polyurethane can significantly eliminate the antibiotic in the presence of ultraviolet irradiation from the effluent of the wastewater treatment plant.
Mohammad Ansarizadeh; Tayebeh Tahamtan; Mostafa Leili; Masoud Yousefi; Ehsan Gharehchahi; Mohsen Kalantari
Abstract
Background: Among chemical dyes, Azo dyes, as environmental synthetic pollutants, are most commonly used in a bunch of different colors in different industries, especially in textile industry to a large extent. Methods: Due to some limitation and difficulties to remove these pollutants from the environment, ...
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Background: Among chemical dyes, Azo dyes, as environmental synthetic pollutants, are most commonly used in a bunch of different colors in different industries, especially in textile industry to a large extent. Methods: Due to some limitation and difficulties to remove these pollutants from the environment, the biological filtering method, as the economically and optimal methods, are preferred. Using the Taguchi method and evaluation of such factors in the environment as temperature pH, color density and concentration of salt, we studied the optimal condition of Halomunas PTCC1132 bacteria decolorization in order to compare it with the Aryapress dye removal from aquatic environment. Therefore, 16 experiments were designed according to Array Table in 4 factors and 4 levels. The results were then analyzed using a computer the program named Qualitek-4. Results: The results showed that this salt, loving bacterium Halomonas strain PTCC1714, has the ability of bleaching in a wide range of salts till 20%, pH (5-9) and dye tolerance up to 5 gr/lit (500 ppm), and has the highest rate of decolorization in 100 ppm. Conclusions: According to the results with an optimal growth condition- the temperature of 40c, pH of 7.5, and the salt concentration of 10% up to 93% - the strain was capable of removing the Azo dye Aryapress color with the concentration of 100 ppm which is a considerable amount and can be used in biological treatment of industrial textile sewage.