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The entry of gentamicin antibiotics into the aquatic environment has raised many concerns. Today, modern nanotechnology-based approaches have been employed to overcome such problems. The present study was conducted to investigate the efficiency of the UV/ZnO photocatalytic process in removing antibiotic gentamicin from aqueous solution. So we investigated the effects of parameters, including initial gentamicin concentrations (20, 60, and 100 mg/L), zinc oxide concentrations (0, 200, 350, and 500 mg/L), contact times (10, 30, 60, and 120 min), pH (5, 6, and 7), and type of radiation (sun and UV-C). The sample size and the number of test procedures were determined to be 576, taking into account the levels of effective variables and through the full factorial. All experiments were carried out in a double-compartment reactor at laboratory temperature using a magnetic stirrer at 150 rpm. The change of gentamicin concentrations were measured using a DR5000 spectrophotometer. Data analysis and charting were done through Design Expert 8 and Excel 2010 software. Results showed that the maximum removal efficiency of gentamicin of about 93% was obtained under UV-C irradiation at pH of 5, contact time of 30 min, ZnO concentration of 200 mg/L, and initial gentamicin concentration of 20 mg/L. In addition, the maximum removal efficiency of gentamicin (84.32%) under sunlight occurred at pH 6, contact time of 60 min, ZnO concentration of 200 mg/L, and initial gentamicin concentration of 20 mg/L. The results demonstrated that the photocatalytic UV/ZnO process exposed to UV-C or natural sunlight could be an effective process for removing antibiotic gentamicin from the aqueous solution.
Insufficiencies and deficiencies in slaughterhouses could adversely affect public health. Wastewater from slaughtering, along with high microbial pollution, results in serious pollution to the surrounding environment if not treated. This study sought to investigate the efficiency of the electrocoagulation process using copper electrodes in the disinfection of poultry slaughterhouse wastewater without any initial controlling. The physical and chemical properties of samples of wastewater taken from a poultry slaughterhouse were first analyzed. Then the samples were subjected to the electrocoagulation process using copper electrodes in potential differences of 10, 20, and 30 V over a period of 60 min. Then the removal efficiency of total coliforms was examined in accordance with standard methods found in textbooks. The results obtained from this study indicated that the efficiency of the electrocoagulation process increased by an increase in process time as well as in electric potential difference. The maximum removal efficiency of total coliforms was 100% in potential difference, equal to 30 V in the reaction time of 10 min. Moreover, the results of this study revealed that the electrocoagulation process using a copper electrode was fully able to remove total coliform from poultry slaughterhouse wastewater.
Colloidal particles are the main cause of turbidity in an aquatic environment. Water turbidity maintains pathogenic microorganisms against disinfection. In addition to increasing the consumption of antiseptic substances, mainly it causes a lot of aesthetic and non-sanitary problems such as the formation of toxic and carcinogenic side constituents in the treatment of water. In this study we investigated the efficiency of the use of tragacanth of Astraglus gossypinus (Catira) on the effectiveness of the electrocoagulation process in the removal of turbidity from brackish water. In this descriptive-analytic study, direct bentonite injections of 2 to 8 g/L were used to provide opacity. In the following, the effect of applying coagulant aid of Tragacanth of Astraglus gossypinus plant with values of 0.25 to 1.5 g/L on the efficiency of the electro-coagulation process equipped with iron electrodes in the removal of opacity from brackish water samples were examined in potential difference from 5 to 30 volts, and pH from 2 to 9 over a period of 60 min. Variation of turbidity was determined using the turbidity sensor in accordance with standard reference methods. The results showed that the highest opacity removal efficiency is about 99% for each 1 kg of opacity due to the addition of 7 g/L bentonite under neutral pH conditions, Tragacanth dose of 1.5 g/L, 8 g/L dose of NaCl, and voltage of 30 V for 30 min, along with the average consumption of iron and electrical energy of 0.18 kg and 0.53 Kwh, respectively. Thus, the use of Astraglus gossypinus tragacanth for removing turbidity as a natural coagulant aid dramatically improves the electrocoagulation process efficiency in the removal of turbidity from brackish water samples and reduces current costs of the electro-coagulation process.
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