40 research outputs found
The survey of Ultrasound – Electrocoagulation process in removal of Ciprofloxacin from aqueous through central composite design
Background and aims: Presence of antibiotics as emerging pollutants have aroused increasing concerns. The modelling of electrocoagulation process with ultrasound in the removal of Ciprofloxacin in aqueous solutions was aimed in the present study.Materials and Methods: In this study a reactor with 1000 mL volume was used. Copper and iron electrodes were exploited as cathode and anode electrodes. Electrodes were connected to a direct electrical current supply as monopolar. The optimization of pH, current density, initial concentration of CIP and reactiontime were conducted by CCD and finally suitable model was presented. In optimized conditions, the amount of electrode corrosion, COD and TOC removal, changes in the UV-Vis adsorption and FT-IR spectrum was measured. All procedures in study were conducted ethically.Results: Optimum conditions were found to occur at pH, current density, and reaction time of 7. 4, 1.5 In this situation the predicted and.A and 30 min, respectively in 15 mg CIP /L as an initial concentration actual efficiencies were 88.21 and 86.37 %, respectively. Also, a moderate COD and TOC removal, about64 and 51 percent was achieved, respectively. Result of FT-IR analysis showed considerable changes in functional groups during removal process. Synergist effect of US in electrocoagulation process was estimated to be only 14 percent.Conclusion: The results indicate that the proposed process have a good efficiency in CIP removal. It is possible to decrease the concentrations of similar pollutants before their discharge to the environment by the use of this method.Keywords: Ultrasound – Electrocoagulation process, modelling, Ciprofloxacin, Central composite design, aqueou
Adsorptive Removal of Methylene Blue in Aqueous Solutions Through Raw and Modified Cantaloupe Peel Wastes: Kinetic and Isotherm Study
Since large amounts of agricultural wastes are produced in Iran and these wastes have lignocellulosic nature, the current study was performed to survey the adsorption performance of methylene blue dye from aqueous solutions by means of raw and modified cantaloupe peel. The adsorbents used were characterized using techniques like scanning electron microscope (SEM), as well as Fourier transform infrared spectroscopy (FTIR). In this study, the effects of a few key variables including pH, reaction time, dye concentration, adsorbent dosage and temperature on the adsorption performance were investigated. Optimum values were attained at 0.04 and 0.08 g doses of modified and raw cantaloupe peel, pH of 7 after mixing for 120 and 90 minutes for raw and modified cantaloupe peel, respectively. The equilibrium information was fitted to the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich equations and the respective data for all models were tested. An increase in adsorbent dose and temperature caused the efficiency to rise. The mechanism and rate of adsorption were ascertained by analyzing the experimental data at various contact times according to traditional kinetic equations: pseudo-first-order and second order, Elovich, and intra-particle diffusion. The findings illustrated that the data accorded closely with the pseudo-second-order model. Moreover, it was found that these wastes can be applied to remove environmental pollutants, particularly methylene blue dye
بررسی فرایند سونو- الکتروکواگولاسیون در حذف سیپروفلوکساسین از محیط های آبی با طراحی ترکیبی مرکزی
Background and aims: Presence of antibiotics as emerging pollutants have aroused increasing concerns. The modelling of electrocoagulation process with ultrasound in the removal of Ciprofloxacin in aqueous solutions was aimed in the present study.Materials and Methods: In this study a reactor with 1000 mL volume was used. Copper and iron electrodes were exploited as cathode and anode electrodes. Electrodes were connected to a direct electrical current supply as monopolar. The optimization of pH, current density, initial concentration of CIP and reactiontime were conducted by CCD and finally suitable model was presented. In optimized conditions, the amount of electrode corrosion, COD and TOC removal, changes in the UV-Vis adsorption and FT-IR spectrum was measured. All procedures in study were conducted ethically.Results: Optimum conditions were found to occur at pH, current density, and reaction time of 7. 4, 1.5 In this situation the predicted and.A and 30 min, respectively in 15 mg CIP /L as an initial concentration actual efficiencies were 88.21 and 86.37 %, respectively. Also, a moderate COD and TOC removal, about64 and 51 percent was achieved, respectively. Result of FT-IR analysis showed considerable changes in functional groups during removal process. Synergist effect of US in electrocoagulation process was estimated to be only 14 percent.Conclusion: The results indicate that the proposed process have a good efficiency in CIP removal. It is possible to decrease the concentrations of similar pollutants before their discharge to the environment by the use of this method.زمینه و اهدف: حضور ترکیبات آنتیبیوتیک بعنوان آلایندههای نوظهور باعث افزایش نگرانی شده است. هدف از این مطالعه، مدلسازی فرایند الکتروکواگولاسیون در حضور امواج التراسوند در حذف سیپروفلوکساسین از محیط آبی است.
مواد و روشها: در این مطالعه، یک راکتور به حجم یک لیتر مورد استفاده قرار گرفت. الکترود مس بعنوان کاتد و الکترود آهن بعنوان آند استفاده شد. اتصال الکترودها به دستگاه تامین کننده جریان الکتریکی مستقیم بصورت تک قطبی پیوسته بود. بهینهسازی پارامترهای pH، جریان الکتریکی، غلظت اولیه سیپروفلوکساسین و زمان واکنش با استفاده از طراحی ترکیبی مرکزی انجام شد و مدل مناسب ارایه شد. در شرایط بهینه فرایند، میزان خوردگی الکترودها، میزان کاهش COD و TOC، تغییرات ایجاد شده در منحنی طیف UV-Vis و طیف سنجی FT-IR اندازهگیری شد. در کلیه مراحل انجام پژوهش، موازین اخلاقی، مراعات گردید.
یافتهها: شرایط مناسب فرایند برای حذف آنتیبیوتیک شامل pH برابر 7/4، جریان الکتریکی 1/5 آمپر، زمان واکنش برابر 30 دقیقه در غلظت اولیه 15 میلیگرم در لیتر بدست آمد. در این حالت بازده تئوریکی و عملی به ترتیب برابر 88/21و 86/37درصد بدست آمد. کاهش COD و TOC به ترتیب برابر 64 و 51 درصد بود. نتایج FT-IR نشان دهنده تغییرات گسترده گروه های عاملی در طی فرایند بود. خاصیت همافزایی حضور امواج التراسوند با توان 350 وات و 40 کیلوهرتز در فرایند الکتروکواگولاسیون 14 درصد تعیین شد.
نتیجه گیری: نتایج بیانگر کارایی نسبتا مناسب فرایند سونوالکتروکواگولاسیون در کاهش میزان سیپروفلوکساسین بود. با استفاده از این روش میتوان پساب حاوی این آلاینده را پس از کاهش غلظت، به محیط دفع نمود.
کلید واژهها: فرایند سونوالکتروکواگولاسیون، مدلسازی، سیپروفلوکساسین، طراحی ترکیبی مرکزی، محیطهای آب
Electrocoagulation Treatment of Color Solution Containing Colored Index Eriochrome Black T
The purpose of this study was to conduct an experimental investigation of decolorization of effluents by the electrocoagulation method. Removal of Eriochrome black T from solution in a batch system was investigated using different voltages (10, 20, 30 volt), electrodes (Al, Fe), electrode distances (2, 4 cm), electrolysis times (0 to 30 min.), and pH levels (3.5, 7, 11). Experimental results showed that removal efficiency depended on electrolysis time and applied current. The experiments carried out at 30V and pH=3.5 further revealed that color removal efficiencies of Fe and Al electrodes over a period of 30 minutes were 96% and 86%, respectively
Electrochemical Removal of COD from Effluents
This study aims to conduct an experimental investigation of treating effluents using the electrochemical method. Removal of COD from effluents was investigated at different electric currents, different electrodes (Al, Fe and Stainless steel), and various electrolysis times. The experimental results show that removal efficiency depends on electrolysis time, type of electrode, and the current applied. From the experiments carried out at 30V, it was found that the efficiency of COD removal over an electrolysis time of 60 minutes was 74% for Al and Fe and 53% for Stainlss steel
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Abstract The purpose of this study was to conduct an experimental investigation of decolorization of effluents by the electrocoagulation method. Removal of Eriochrome black T from solution in a batch system was investigated using different voltages (10, 20, 30 volt), electrodes (Al, Fe), electrode distances (2, 4 cm), electrolysis times (0 to 30 min.), and pH levels (3.5, 7, 11). Experimental results showed that removal efficiency depended on electrolysis time and applied current. The experiments carried out at 30V and pH=3.5 further revealed that color removal efficiencies of Fe and Al electrodes over a period of 30 minutes were 96% and 86%, respectively
Prevalence and Removal Efficiency of Enterococcal Species and Vancomycin-resistant Enterococci of a Hospital Wastewater Treatment Plant
Simultaneous presence of various antibiotics and bacteria in hospital wastewaters creates a suitable environment, in which the bacteria, such as enterococci become resistant to the antibiotics. The aim of this study was to evaluate the performance of different units of the hospital wastewater treatment plant (HWTP) to remove Enterococcus spp and Vancomycin-resistant Enterococcus (VRE). The study was performed on the 27 samples collected from HWTP in Hamedan, Iran during December 2014 to August 2015. Enterococcus spp and VRE were identified by biochemical tests and then the isolates were confirmed by PCR. Finally, the antibiotic susceptibility test was performed using disk diffusion methods. Of the 27 samples examined, 315 a total of enterococcal isolates were obtained. Of the 315 isolates of enterococci investigated, 162 (51.42%) were identified as E. faecium, 87 (27.61%) as E. hirae, 35 (11.11%) as E. faecalis, 11 (3.5%) as E. gallinarum, 7 (2.22%) as E. casseliflavus, 4 (1.26%) E. avium, and 9 (2.85%) isolates VR E. faecium.The results of antibiotic susceptibility testing showed that of the total 315 isolates, 146 (46.34%) were resistance to tetracycline, 9 (2.85%) were resistance to vancomycin and Teicoplanin. Lower antibiotic resistance was seen with Nitrofurantoin 2 (1.26%). This study indicates a high prevalence of multidrug resistance among E. faecium isolated from HWTP, thus, it could be considered as a threat to the health and safety of wastewater workers and even public health
Performance Evaluation of Magnetite Nanoparticles Modified with Sodium Alginate for the Removal of Acid Red 18 Dye from Aqueous Solutions
Background: Azo dyes have many applications in various industries. In addition to Mutagenic and carcinogenic potential to humans, these materials cause the production of toxic byproducts in the aqueous solutions. In this study, magnetite nanoparticles were synthesized with modified sodium alginate. Then their efficiencies in absorbing Acid Red 18 dye were investigated.
Methods: First, magnetite nanoparticles were synthesized by chemical co-precipitation method and then modified magnetite nanoparticles were evaluated as an adsorbent for Acid Red 18 dye adsorption. TGA test was used for proving modified magnetite nanoparticles coating.
The effects of pH, contact time, nanoparticles and Acid Red 18 dye concentrations were studied.
Residual concentration of Acid Red 18 dye was read using a spectrophotometer at a wavelength of 508 nm. Data was explained by the Langmuir isotherm and Freundlich models.
Results: In optimal conditions of operation including pH = 5, contact time =30 minutes, adsorbent dose 0/2gr/l and the initial concentration of Acid Red 18 dye= 50 mg/l, removal efficiency of the process was obtained over 95 %. These studies also showed that Acid Red 18 absorption pattern has more conformity with the Freundlich model.
Conclusion: The results showed that sodium alginate is a convenient and inexpensive coating for magnetite nanoparticles; also it has high efficiency to absorb dye Acid Red 18 in a short time
Comparing the performance of granular coral limestone and Leca in adsorbing Acid Cyanine 5R from aqueous solution
The effect of granular coral limestone and Leca as adsorbents for removing Acid Cyanine 5R (AC5R) from aqueous solution was studied. The optimum pH and adsorbent particles size in both adsorbents were determined to be 3 and 297 μm, respectively. The optimum dosages of coral limestone and granular Leca were 0.150 and 0.145 g/mg of dye, respectively. Also, results have shown that the adsorption efficiency by both coral limestone and Leca increased with the decreasing adsorbent particles size. Moreover, under similar conditions, the maximum removal efficiency by granular coral limestone and Leca was 94% and 88%, respectively. The results revealed that the performance of granular coral limestone was better in AC5R removal than that of Leca granulated under such condition. In total, granular coral limestone and Leca act as suitable adsorbents for removing dye pollutants from an aqueous solution
Removal of Cr (III) from model solutions and a real effluent by Phanerochaete chrysosporium isolated living microorganism: equilibrium and kinetics
International audienceRemoval of Cr (III) was investigated using Phanerochaete chrysosporium-isolated living microorganism; pH, contact time, temperature and nutrients addition were examined. It was found that P. chrysosporium can tolerate up to 600 mg/L chromium solution. The optimal growth conditions of the biosorbent were found to be 35°C, 26 h contact time and pH = 5. In addition, a complex nitrogen substrate, yeast powder, was shown to be most efficient than a synthetic one, like di-hydrogen ammonium phosphate. High chromium removal (98%) was observed in these optimal growth conditions. Experimental data were found to follow a Langmuir isotherm model (r 2 > 0.99). Maximum sorption capacity for the present biosorbent was 213 mg/g according to the Langmuir isotherm model, namely significantly higher than the values reported in the literature, even for activated carbon. The fitting of experimental data onto kinetic models showed the relevance of the pseudo-second-order model (r 2 > 0.99) for Cr (III) sorption by P. chrysosporium. In addition, a real effluent was obtained from tanning factory and was treated to examine process feasibility on real effluents