آب و فاضلاب (Oct 2022)
Pharmaceutical Pollutants Removal by Using Electrochemical Oxidation Technique
Abstract
Pharmaceutical industries, due to the production of a wide range of drugs, have pharmaceutical effluents and wastewater in various types of synthetic, chemical, biological drugs, etc. The entry of these substances into the cycle of the environment and human life is extremely harmful and carries serious risks. Therefore, pharmaceutical wastewater treatment is of great importance in industry. There are various methods on an industrial scale to remove contaminants and pharmaceutical effluents, among them, electrochemical and oxidation-based methods are very suitable for industrial and medical applications due to technical-economic justification. In this study, the removal of contaminants in drug effluents was investigated using the oxidation process. In order to evaluate and determine the characteristics of high-consumption drugs (aspirin, atorvastatin, metformin, metronidazole, and ibuprofen), using a potentiostat device with a three-electrode cell, a cyclic voltammetric diagram with a 100 mV/s scanning rate was performed until the initial and peak conditions were reached. Oxidation of drug samples were evaluated. Then, using the chronoamperometry process (constant potential application), the drugs were subjected to an electrochemical oxidation process (using three-electrode cells), and the drug removal process was performed for insoluble and liquid samples. At the end of the chronoamperometry method (drug removal), the samples were again subjected to cyclic voltammetry test, and the level below the oxidation peaks of the sample was calculated and compared with the level below the initial peak, thus determining the removal efficiency of the sample (removal rate). The results indicate that this method has shown about 70% efficiency for removing selected drugs with a high removal efficiency and for the atorvastatin sample specifically, it was about 100%. It should be noted that the oxidation time of each drug varies according to the type of drug and the concentration of the drug under study. About 100 to 500 seconds seems to be enough to remove the drug in most cases. The oxidation potential of selected drugs is in the range of -0.8 V. Therefore, according to the results obtained, this method has high and sufficient accuracy (RSD about 2%).
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