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The removal efficiency of the emerging antibiotic waste, amoxicillin, from aqueous media was investigated using the electro-Fenton method with an aluminum anode through the one-factor-at-a-time method, and all the experiments were performed in a useful volume of 750 ml. While the optimum conditions were achieved, the removal kinetic of the contaminant from the environment was investigated. Optimal values of the process parameters including the concentration of the contaminant, process time, initial pH of the samples, electrolyte concentration, electrode distance, and the applied current density were determined as 100 mg. l− 1, 90 min, neutral pH, 0.02 M Na 2 SO 4, 5.5 cm, and 5.5 mA. cm− 2, respectively. In order to find the optimum con
In this study, electro-coagulation-flotation process was investigated in the new baffled reactor to use the advantage of simultaneous flotation in an individual compartment to eliminate the need of separate chamber for flotation. The middle baffle led to the production of larger and denser flocs and consequently, settling velocity, sludge volume index, and floc density increased by 63%, 13%, and 14%, respectively. Effective parameters of electro-coagulation-flotation process in the proposed reactor were optimized due to treatment of Direct Blue 71. In the optimal condition ([dye]=200 mg/L, electrical conductivity=6.7 mS/cm, current density=3.54 mA/cm 2, and pH=8 in 60 min), the removal efficiency of dye, naphthalene ring, COD, and TOC, aver
This study aimed to improve the speed of the electrochemical process by graphene oxide nanoparticle as a current accelerator in Acid Blue 25 removal from aqueous solutions. To do so, the effect of different parameters including pH, dye concentration, sodium persulfate concentration, the ratio of sodium persulfate to iron (II) sulfate concentration, current density, and the distance between electrodes was investigated on dye removal. Under optimal conditions of pH = 5, dye concentration = 200 mg/L, sodium persulfate concentration = 500 mg/L, iron (II) sulfate concentration = 100 mg/L, current density = 16.67 mA/cm2, and electrode distance = 2 cm, 95% of dye was removed after 60 minutes in the electro-activated persulfate process; wh
Phosphate removal is an important measure to control eutrophication in aquatic environments, as it inhibits algal bloom. Salinity exists in these media along with high phosphate and currently available phosphate removal methods function poorly under this condition. In this study, the main objective is to fabricate a nanocomposite to improve and accelerate phosphate removal from saline solutions. To achieve this goal, Fe3O4/ZnO and a novel nanoadsorbent, Fe3O4/ZnO/CuO, were synthesized. Their characteristics were determined using FE-SEM, EDX, FT-IR, and XRD analyses, and their capability to adsorb phosphate from saline solutions was investigated and compared. The overall results suggest that the trimetallic oxide nanocomposite has a
In this study, numerical simulation of hydrodynamic and dye concentration changes using a novel electro-peroxone process was performed using a new baffled reactor. The effects of three different electrode arrangements and three flow rates were investigated to optimize dye removal efficiency and mass transfer rate; and also to evaluate a fundamental relationship between the mass transfer coefficients and the reactor's characteristics. Based on the results, the electrodes' arrangement had a significant effect on the fluid's maximum velocity and increased it at the electrode surface by more than 50%. It was also observed that changing the electrodes' number and position from the first to the third arrangement (increasing the number of the elec
The hydrogen peroxide role in photocatalytic degradation of an anionic azo dye, Acid Orange 7 (AO7), was investigated in a slurry reactor. Commercial ZnO nanoparticles with an average size between 10 to 30 nm were used as catalysts. Optimum conditions for different parameters, including dye concentration (10–100 mg/L), catalyst concentration (0.1–0.5 g/L), and pH (5–10), were determined first in the absence of H2O2. Changes in the COD were measured for the optimum condition. The impact of adding hydrogen peroxide at different concentrations to the system operating at optimum conditions was investigated. It was observed that 0.416 mM hydrogen peroxide increased the system's efficiency and decreased reaction time by 40 min. The
The textile industry wastewater causes serious environmental problems due to its high toxicity and color. Therefore, it is necessary to find an effective treatment technology for removing organic dyes from wastewater. Cavitation is one such modern technique which has been considered for the treatment of complex pollutants because of its ability to generate highly reactive free radicals. Up to now, researchers have mostly focused on qualitative interpretations and related scientific techniques, and there has been no quantitative cost analysis for pollutant control in textile industries for decision making purposes. Future studies need to focus on the cost analysis of more processes in textile wastewater treatment, such as advanced oxidation
In recent decades the electro-Fenton process has widely been utilized for removing recalcitrant compounds. However, this process is accompanied by several problems such as limited working pH range, production of significant amount of iron sludge, and incapability in reusing used iron ions. Hence, the heterogeneous electro-Fenton process is a convenient way to address these problems. One of the shortcomings of this method, in comparison with the homogeneous electro-Fenton process, is its lower reaction rate. In the first phase of this study, a heterogeneous Fe-based nanocatalyst was prepared. After optimizing the affecting parameters, three transition metals (M: Cu, Co and, Cr) were used in the second phase of the study to improve the perfor
In this study, a modified electro Fenton system, a heterogeneous nanocatalyst Fe-ZSM-5, and an innovative reactor with orbiting graphite electrodes were used to remove the acid blue 25. Heterogeneous nanocatalysts are divided into natural and synthetic categories, which have advantages such as increasing the working pH range, reducing the leakage of transition metal into the solution, reducing the sludge volume, and reusability in several cycles. In this study, Fe-ZSM-5 nanocatalyst was synthesized by ZSM-5 nano zeolite, iron ion, using the wet impregnation method. After its characterization by XRD, FTIR, and FESEM analyses, the capability of the nanocatalyst in electro Fenton process for dye removal was investigated by the OFAT method. Und
Electro-peroxone system is a novel environmental friendly technology which attracts so much attention. This process is based on reaction of hydrogen peroxide generated through electrochemical process with ozone to produce hydroxyl radicals. In this study effects of electrode arrangement, anode surface area and position compare to cathode electrodes were investigated for the first time on dye removal efficiency of electro-peroxone in a baffled reactor. Oxidation state was also used to investigate degradation of Acid Orange 7 by-products. According to the results, electrodes arrangement and increasing the ratio of the anode to cathode surface area improved the performance of the electro-peroxone process. However placing anode electrode before
The aim of this study was to investigate the removal of acid orange 7 from aqueous solution using a new triple nanocomposite biochar/ZnO/SnO 2. In this experimental study, weight percentages of ZnO, weight percentages of SnO 2, pH, dye concentration and nanocomposite dosage as effective parameters on removal of acid orange 7 using one factorial method were analyzed. The maximum dye removal efficiency of 96.92% obtained at optimum conditions, 20% weight ratio for ZnO, 5% weight ratio for SnO 2, pH= 7.1, 250 ppm dye concentration, 0.5 g/L nanocomposite dose after 60 minute. One of the highlights of the nanocomposite was its high power to remove dyes in a very short time. As after 2 minutes of testing, most of the dye (about 86%) was removed.
Petroleum is the major source of energy and the activities related to the petroleum industry leading to high volumes of wastewater and emissions different pollutants to water systems. According to studies, world oil demand will increase to about 107 million barrels a day over the next two decades, and about 32 percent of global energy will be provided from Petroleum by 2030. Thus wastewater resulting from oil and refinery industry is increasingly rising and discharges into the environment, which is a serious threat to the world's water resources. A large amount of water is used to extract and to refine the petroleum in oil refineries, thus produce the large amounts of wastewater. The wastewaters containing various kinds of pollutants with d
Electro-peroxone is a novel advanced oxidation process that surpasses ozonation or peroxone because of its advantages. In this technology, combining ozone and hydrogen peroxide generated electrochemically leads to the production of hydroxyl radicals, which are the strongest oxidizing agents. In this study, a cylindrical reactor with a continuous circular flow using novel arrangements of electrodes was used to examine the effects of variant parameters on dye removal efficiency. Acid Orange 7 (C16H11N2NaO4S) served as an indicator pollutant. Based on overall energy consumption and energy consumption per dye removed weight, electro-peroxone not only has proper efficiency at high dye concentrations, it also has the least energy consumption per
A large quantity of water is used at oil refineries; Consequently, high amounts of wastewater are produced. The main aim of this study is to evaluate COD removal rate using an electrocoagulation process as well as a photocatalytic process with ZnO nanoparticles. Subsequently, the combined treatment was also implemented to reach energy savings and higher performance. At the optimum condition of the EC process (COD concentration of 900 m/L, current density of 20 mA/cm2, pH of 8.5 and NaCl concentration of 0.5 g/L), COD removal rate was 94% after 60 min. For the photocatalytic process at optimum conditions (COD concentration of 600 mg/L, ZnO concentration of 80 g/m2, pH of 5 and irradiation power of 32 W), 76% of COD removal effi
This study assessed the role of a new Acinetobacter calcoaceticus strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3-gfp strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07? 10 7 more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3-gfp in R2 were unab