Golshan Moradi; Sirus Zinadini; Masoud Rahimi
Abstract
The research on membrane-based filtration technology for water treatment has expanded in recent years. Membrane fouling is a major challenge that decreases the permeability and decreases the lifetime and selectivity of the membrane. Recently, it was found that fouling mitigation and better control of ...
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The research on membrane-based filtration technology for water treatment has expanded in recent years. Membrane fouling is a major challenge that decreases the permeability and decreases the lifetime and selectivity of the membrane. Recently, it was found that fouling mitigation and better control of membrane fouling can be attained under the application of the electric field. This paper provides an overview of the application of the electric field to the filtration process and its antifouling mechanism. Utilization of conductive polymeric membranes and application of electric field in membrane bioreactors are reviewed as well. The presented review demonstrates that the introduction of negative charge into the membrane surface via preparing conductive membranes or applying an external electric field onto the membrane surface suggests several advantages. These are fouling alleviation, better control of membrane fouling, an increase of membrane resistance to cake deposition on the membrane surface, and superior possible applications such as better salt rejection and antibacterial activity.
Salah Meddah; Imene Djeghader; Mohamed El-Hadi Samar; Fadhel Ismail
Abstract
The objective of this work was to model and optimize the degradation of black azodye Naphthol Blue Black (NBB) by the Fenton process (advanced oxidation)using a minimum of experiments. A Plackett-Burman screening design was firstapplied to determine the main factors influencing the process. The dyediscoloration ...
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The objective of this work was to model and optimize the degradation of black azodye Naphthol Blue Black (NBB) by the Fenton process (advanced oxidation)using a minimum of experiments. A Plackett-Burman screening design was firstapplied to determine the main factors influencing the process. The dyediscoloration efficiency gave a yield approximately equal to 97 % in the bestconditions of several operating parameters used. The variance analysis (ANOVA)showed the effects of all different factors and deduced the most important ones.Subsequently, a second quadratic design of experiments central composite type(CCD) was applied using the response surface methodology (RSM) to optimizethe most important parameters deduced by the first design cited above, in order toobtain the best performance of the discoloration of NBB with this process. So from the contour plots and the response surfaces, the discoloration yield enhanced to the maximum and the optimization plot given by the Mnitab software, showed the following optimized parameters [NBB]=37.5 mg/L, [H2O2]=66.5 mg/L, [Iron]=3.5 mg/L and pH=3.4 for a yield of 100 % with a desirability of 1.0000. At last, to confirm that the discoloration was due to the degradation of the dye, the chemical oxygen demand (COD) was studied and in the optimized conditions, the degradation reached 94.78 % after 120 min of treatment. The kinetics of the dye degradation showed by the COD abatement was relatively slow compared to the kinetics of the dye discoloration.
Masumeh Heidarzadeh; Nourollah Abdi; Javad Varvani Farahani; Abbas Ahmadi; Hamid Toranjzar
Abstract
A mixture of urban and industrial wastewater is discharged into the Meighan wetland, Arak, Iran. The heavy metals containing wastewater leads to environmental hazards whereby phytoremediation can be used for removing pollutants from contaminated water. An essential native plant that is abundant in the ...
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A mixture of urban and industrial wastewater is discharged into the Meighan wetland, Arak, Iran. The heavy metals containing wastewater leads to environmental hazards whereby phytoremediation can be used for removing pollutants from contaminated water. An essential native plant that is abundant in the Meighan wetland is Typha Latifolia L. The effect of T. Latifolia L. was investigated on the removal of heavy metals (aluminum, zinc, copper, and nickel) at the inlet of Arak wastewater treatment plant into Meighan wetland. The soil (0-30 cm in depth) and plants (aerial and root biomass) were sampled in September 2019. In the laboratory, heavy metal accumulation in samples was measured via atomic absorption method. The results of analysis of variance (ANOVA) revealed that the concentrations of all four metals were significantly different across the soil, root, and aerial biomass. The results of mean comparison by Duncan's test indicated that the highest concentration of aluminum was in the soil, while the lowest in aerial parts. Copper was maximum in the root, and the minimum was found in the aerial parts. Also, the concentration of zinc was the highest in the root, and the lowest in the soil. And, nickel was maximum in the soil while being minimum in the root. Data showed that the concentrations of aluminum in the soil, root, and aerial biomass of T. Latifolia L. were multiple times higher than permissible limit. The concentration of nickel in the soil was slightly higher than the acceptable limit, but the concentrations of other heavy metals in the soil, in aerial biomass, and in the root of T. Latifolia L. were within the acceptable range. The results indicated T.Latifolia L. is a suitable plant for the phytoremediation and water treatment in the Meighan wetland.
Simin Shokrolahi; Mehrdad Farhadian; Nila Davari
Abstract
ZnO/Fe2O3/Zeolite nanophotocatalyst was synthesized by sol-gel method, and its performance in degradation of ENR, as one of the most commonly used veterinary antibiotics, is evaluated. The synthesized nanophotocatalyst is characterized by XRD, XRF, FT-IR, FE-SEM, EDX, and BET analyses. According to XRD, ...
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ZnO/Fe2O3/Zeolite nanophotocatalyst was synthesized by sol-gel method, and its performance in degradation of ENR, as one of the most commonly used veterinary antibiotics, is evaluated. The synthesized nanophotocatalyst is characterized by XRD, XRF, FT-IR, FE-SEM, EDX, and BET analyses. According to XRD, FT-IR, and EDX, presence of ZnO and Fe2O3 on the zeolite surface is confirmed. Based on XRF results, the optimal molar value of Fe3+/ZnO in the synthesized nanophotocatalyst is obtained as 0.06. The FE-SEM results confirm the deposition of ZnO/Fe2O3 on the zeolite surface and indicate the approximate size of the photocatalyst particles as 48 nm. According to BET results, the specific surface area and pore volume for the synthesized nanophotocatalyst are obtained as 280.16 m2/g and 0.35 cm3/g, respectively. The simultaneous effects of operational factors, including the concentration of pollutant (150-450 mg/l), initial pH of the solution (5-9), and H2O2 concentration (50-200 mg/L) are examined on the ENR degradation efficiency via RSM. The results demonstrate that ENR concentration, pH, and H2O2 concentration have significant impacts on the ENR degradation efficiency in turn. According to the experimental results under optimal conditions (pH, contaminant concentration, and H2O2 concentration: 9, 500 mg/l, and 90 mg/l, respectively), the ENR degradation efficiency is 97.4%. This study suggests that the synthesized nanophotocatalyst has an acceptable efficiency to degrade a non-biodegradable contaminant.
Nafiseh Aghababaei
Abstract
Reverse osmosis (RO) has proven to be an efficient technique for desalination of seawater, brackish water, and reclaimed wastewater. However, the performance of RO desalination is sensitive to its design parameters and operating conditions. The purpose of this study was to modeling the removal of total ...
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Reverse osmosis (RO) has proven to be an efficient technique for desalination of seawater, brackish water, and reclaimed wastewater. However, the performance of RO desalination is sensitive to its design parameters and operating conditions. The purpose of this study was to modeling the removal of total dissolved solids (TDS) and Rejection of different ions are reported from water of city of Bandar Abbas. The main purpose of this work was the prepared drinking water intrusion model. In this study, a design method based on a simulation technique has been developed for optimizing RO desalination systems. The design is made with the use of Hydranautics design software version 2011. In this paper main focus is on the design part with software. The desalinated water obtained from reverse osmosis at a pressure of 1.2 MPa showed rejections of approximately 88.49 % for SO4 2 −, 61.42 % for TDS, 70.34 for Cl- and 50.85 for Na+. It shows that software gives accurate design with least possible error and user friendly so world while accepted. Blended water, produced by mixing groundwater and surface, was proposed to optimize the produce drinking water with a recovery rate of 95 %. Reverse osmosis is an excellent alternative for the supply of water in Bandar Abbas.
