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Svetlozar Velizarov - One of the best experts on this subject based on the ideXlab platform.
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optimisatIon of arsenate removal from water by an integrated Ion Exchange Membrane process coupled with fe co precipitatIon
Separation and Purification Technology, 2020Co-Authors: Mafalda Pessoa Lopes, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Abstract The present work investigates the performance of an Ion-Exchange Membrane process for arsenate removal, consisting in integrating Donnan dialytic transport of arsenic with its simultaneous precipitatIon in a separate receiver compartment. The process performance was improved by adding a bicarbonate-carbonate buffer in the receiver solutIon, where iron (III) chloride was used to precipitate the arsenic. This system allowed to maintain the treated water pH within the acceptable drinking water range of 6–9, without further control. A Response Surface Methodology (RSM) was used to infer about the effect of the supply water characteristics (initial arsenic concentratIon and pH) and operating conditIons (mass ratio of iron to arsenic) on the degree of arsenic removal. It was found that the initial pH of the receiver solutIon was also a required input to predict accurately the arsenic concentratIon in the treated water (for a predefined treatment time). The model developed has a fitting R2 value of 0.99 and a predictIon error of 6.6 µg/L of As. The methodology presented permits to develop a simple decisIon tool (either through the use of equatIons or visual plots) to determine the effective amount of iron to be used in the treatment of As contaminated water.
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arsenate removal from sulphate containing water streams by an Ion Exchange Membrane process
Separation and Purification Technology, 2016Co-Authors: Mafalda Pessoalopes, Joao G Crespo, Svetlozar VelizarovAbstract:Abstract A possible limitatIon of applying Donnan dialysis for arsenate removal from drinking water supplies is when sulphate is present as an accompanying anIon in the water to be treated, due to strong competitIon between arsenate and sulphate transport through standard grade anIon-Exchange Membranes. This work aims at evaluating the feasibility of employing an Ion-Exchange Membrane Donnan dialysis based process with a new strategy of using sulphate as the driving counter-Ion for arsenate counter-transport and removal from sulphate-containing drinking water streams. The process performance with different arsenate receiving solutIons (containing chloride or sulphate as driving counter-Ions and with or without arsenic precipitatIon) was investigated and compared. Experiments were carried out to separate arsenate from contaminated water comparing the performance of three anIon-Exchange Membranes: one with mono-valent anIon permselective properties and two standard grade Membranes. As selectIon criteria, the transport rate of arsenate and its Membrane retentIon were investigated. The effects of pH variatIon and co-Ion (catIon) leakage on the Donnan dialysis process efficiency were also studied. Efficient arsenic removal was achieved through integrating Donnan dialytic transport of arsenate with its simultaneous precipitatIon in the receiving compartment with FeSO 4 . The process proposed is environmentally friendly and with minimal maintenance requirements, which makes it especially attractive to be applied in rural areas located far from centralized drinking water supply infrastructures.
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2d fluorescence spectroscopy for monitoring Ion Exchange Membrane based technologies reverse electrodialysis red
Water Research, 2016Co-Authors: Sylwin Pawlowski, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Reverse electrodialysis (RED) is one of the emerging, Membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operatIon constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detectIon is one of the main challenges for successful RED technology implementatIon. In the present study, two-dimensIonal (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitatIon-emissIon matrices (EEMs) of Ion-Exchange Membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operatIon. Fouling evolvement on the Ion-Exchange Membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). AdditIonally, the efficiency of cleaning strategy was assessed by measuring the Membrane fluorescence emissIon intensity before and after cleaning. The anIon-Exchange Membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the Membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and Membrane cleaning efficiency in Ion Exchange Membrane processes.
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2d fluorescence spectroscopy for monitoring Ion Exchange Membrane based technologies reverse electrodialysis red
Water Research, 2016Co-Authors: Sylwin Pawlowski, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Reverse electrodialysis (RED) is one of the emerging, Membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operatIon constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detectIon is one of the main challenges for successful RED technology implementatIon. In the present study, two-dimensIonal (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitatIon-emissIon matrices (EEMs) of Ion-Exchange Membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operatIon. Fouling evolvement on the Ion-Exchange Membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). AdditIonally, the efficiency of cleaning strategy was assessed by measuring the Membrane fluorescence emissIon intensity before and after cleaning. The anIon-Exchange Membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the Membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and Membrane cleaning efficiency in Ion Exchange Membrane processes.
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mercury removal from water streams through the Ion Exchange Membrane bioreactor concept
Journal of Hazardous Materials, 2014Co-Authors: Adrian Oehmen, Joao G Crespo, Maria A M Reis, Dario Vergel, Joana Fradinho, Svetlozar VelizarovAbstract:Mercury is a highly toxic heavy metal that causes human health problems and environmental contaminatIon. In this study, an Ion Exchange Membrane bioreactor (IEMB) process was developed to achieve Hg(II) removal from drinking water and industrial effluents. Hg(II) transport through a catIon Exchange Membrane was coupled with its bioreductIon to Hg(0) in order to achieve Hg removal from concentrated streams, with minimal productIon of contaminated by-products observed. This study involves (1) Membrane selectIon, (2) demonstratIon of process effectiveness for removing Hg from drinking water to below the 1ppb recommended limit, and (3) process applicatIon for treatment of concentrated water streams, where >98% of the Hg was removed, and the throughput of contaminated water was optimised through Membrane pre-treatment. The IEMB process represents a novel mercury treatment technology with minimal generatIon of contaminated waste, thereby reducing the overall environmental impact of the process.
Joao G Crespo - One of the best experts on this subject based on the ideXlab platform.
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optimisatIon of arsenate removal from water by an integrated Ion Exchange Membrane process coupled with fe co precipitatIon
Separation and Purification Technology, 2020Co-Authors: Mafalda Pessoa Lopes, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Abstract The present work investigates the performance of an Ion-Exchange Membrane process for arsenate removal, consisting in integrating Donnan dialytic transport of arsenic with its simultaneous precipitatIon in a separate receiver compartment. The process performance was improved by adding a bicarbonate-carbonate buffer in the receiver solutIon, where iron (III) chloride was used to precipitate the arsenic. This system allowed to maintain the treated water pH within the acceptable drinking water range of 6–9, without further control. A Response Surface Methodology (RSM) was used to infer about the effect of the supply water characteristics (initial arsenic concentratIon and pH) and operating conditIons (mass ratio of iron to arsenic) on the degree of arsenic removal. It was found that the initial pH of the receiver solutIon was also a required input to predict accurately the arsenic concentratIon in the treated water (for a predefined treatment time). The model developed has a fitting R2 value of 0.99 and a predictIon error of 6.6 µg/L of As. The methodology presented permits to develop a simple decisIon tool (either through the use of equatIons or visual plots) to determine the effective amount of iron to be used in the treatment of As contaminated water.
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arsenate removal from sulphate containing water streams by an Ion Exchange Membrane process
Separation and Purification Technology, 2016Co-Authors: Mafalda Pessoalopes, Joao G Crespo, Svetlozar VelizarovAbstract:Abstract A possible limitatIon of applying Donnan dialysis for arsenate removal from drinking water supplies is when sulphate is present as an accompanying anIon in the water to be treated, due to strong competitIon between arsenate and sulphate transport through standard grade anIon-Exchange Membranes. This work aims at evaluating the feasibility of employing an Ion-Exchange Membrane Donnan dialysis based process with a new strategy of using sulphate as the driving counter-Ion for arsenate counter-transport and removal from sulphate-containing drinking water streams. The process performance with different arsenate receiving solutIons (containing chloride or sulphate as driving counter-Ions and with or without arsenic precipitatIon) was investigated and compared. Experiments were carried out to separate arsenate from contaminated water comparing the performance of three anIon-Exchange Membranes: one with mono-valent anIon permselective properties and two standard grade Membranes. As selectIon criteria, the transport rate of arsenate and its Membrane retentIon were investigated. The effects of pH variatIon and co-Ion (catIon) leakage on the Donnan dialysis process efficiency were also studied. Efficient arsenic removal was achieved through integrating Donnan dialytic transport of arsenate with its simultaneous precipitatIon in the receiving compartment with FeSO 4 . The process proposed is environmentally friendly and with minimal maintenance requirements, which makes it especially attractive to be applied in rural areas located far from centralized drinking water supply infrastructures.
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2d fluorescence spectroscopy for monitoring Ion Exchange Membrane based technologies reverse electrodialysis red
Water Research, 2016Co-Authors: Sylwin Pawlowski, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Reverse electrodialysis (RED) is one of the emerging, Membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operatIon constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detectIon is one of the main challenges for successful RED technology implementatIon. In the present study, two-dimensIonal (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitatIon-emissIon matrices (EEMs) of Ion-Exchange Membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operatIon. Fouling evolvement on the Ion-Exchange Membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). AdditIonally, the efficiency of cleaning strategy was assessed by measuring the Membrane fluorescence emissIon intensity before and after cleaning. The anIon-Exchange Membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the Membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and Membrane cleaning efficiency in Ion Exchange Membrane processes.
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2d fluorescence spectroscopy for monitoring Ion Exchange Membrane based technologies reverse electrodialysis red
Water Research, 2016Co-Authors: Sylwin Pawlowski, Claudia F Galinha, Joao G Crespo, Svetlozar VelizarovAbstract:Reverse electrodialysis (RED) is one of the emerging, Membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operatIon constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detectIon is one of the main challenges for successful RED technology implementatIon. In the present study, two-dimensIonal (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitatIon-emissIon matrices (EEMs) of Ion-Exchange Membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operatIon. Fouling evolvement on the Ion-Exchange Membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). AdditIonally, the efficiency of cleaning strategy was assessed by measuring the Membrane fluorescence emissIon intensity before and after cleaning. The anIon-Exchange Membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the Membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and Membrane cleaning efficiency in Ion Exchange Membrane processes.
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mercury removal from water streams through the Ion Exchange Membrane bioreactor concept
Journal of Hazardous Materials, 2014Co-Authors: Adrian Oehmen, Joao G Crespo, Maria A M Reis, Dario Vergel, Joana Fradinho, Svetlozar VelizarovAbstract:Mercury is a highly toxic heavy metal that causes human health problems and environmental contaminatIon. In this study, an Ion Exchange Membrane bioreactor (IEMB) process was developed to achieve Hg(II) removal from drinking water and industrial effluents. Hg(II) transport through a catIon Exchange Membrane was coupled with its bioreductIon to Hg(0) in order to achieve Hg removal from concentrated streams, with minimal productIon of contaminated by-products observed. This study involves (1) Membrane selectIon, (2) demonstratIon of process effectiveness for removing Hg from drinking water to below the 1ppb recommended limit, and (3) process applicatIon for treatment of concentrated water streams, where >98% of the Hg was removed, and the throughput of contaminated water was optimised through Membrane pre-treatment. The IEMB process represents a novel mercury treatment technology with minimal generatIon of contaminated waste, thereby reducing the overall environmental impact of the process.
Yoshinobu Tanaka - One of the best experts on this subject based on the ideXlab platform.
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computer simulatIon of Ion Exchange Membrane electrodialysis for salt concentratIon and reductIon of ro discharged brine for salt productIon and marine environment conservatIon
Desalination, 2015Co-Authors: Yoshinobu Tanaka, M Reig, S Casas, C Aladjem, J L CortinaAbstract:Abstract The salt discharged from reverse osmosis is concentrated by Ion-Exchange Membrane electrodialysis to produce salt for industrial use and the salt concentratIon is reduced to seawater level for preventing environmental impact on marine ecosystems. The technology was evaluated experimentally and discussed with a computer simulatIon program of the electrodialysis system incorporated with U shape cells. The algorithm computes mass transport, energy consumptIon, electric current leakage, concentrate NaCl purity, pressure drop and limiting current density. The seawater reverse osmosis discharged brine was supplied to the electrodialysis pilot plant and it was operated changing current density and temperature taking benefit of seasoning variatIons. The computed energy consumptIon ENaCl and NaCl concentratIon in concentrated solutIons C″NaCl using developing algorithms provided a good descriptIon of the experimentally measured values with correlatIon coefficients of R(r) = 0.9 for ENaCl and R(r) = 0.6 for C″NaCl. Then the reasonability of the developed algorithms is supported by the experimental set of data. The current leakage is nearly 3% for any electric current. The pump driving force is very low. The limiting current density is very high. In order to decrease salt concentratIon at the outlets of desalting cells to seawater level, it is necessary to increase desalting ratio to 0.5. This technique however increases ENaCl and decrease C″NaCl. In spite of this operating circumstance, ENaCl and C″NaCl are comparable to the data in the salt manufacturing plant operatIon to produce edible salt. NaCl produced from in the reverse osmosis discharged brine electrodialysis is competitive in the edible salt market.
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Limiting Current Density
Ion Exchange Membranes, 2015Co-Authors: Yoshinobu TanakaAbstract:When an electric current passes through an Ion Exchange Membrane, salt concentratIon on the desalting surface of the Membrane decreases because of concentratIon polarizatIon and reduces to zero at the limiting current density. In this circumstance, there are no more salt Ions available to carry the electric current; as a result, the voltage drop across the boundary layer increases drastically and causes higher energy consumptIon and the generatIon of water dissociatIon. The limiting current density of an Ion Exchange Membrane i lim is measured using the current–voltage relatIonship. The mechanism of i lim can be understood from the Nernst diffusIon model and analyzed with chemical engineering techniques. When the current density reaches i lim at the outlet of a desalting cell at its lowest linear velocity and electrolyte concentratIon, the average current density applied to an electrodialyzer is defined as limiting current density ( I / S ) lim . The solutIon velocity distributIon in an electrodialyzer strongly influences ( I / S ) lim .
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Mass transport in a boundary layer and in an Ion Exchange Membrane: Mechanism of concentratIon polarizatIon and water dissociatIon
Russian Journal of Electrochemistry, 2012Co-Authors: Yoshinobu TanakaAbstract:In an unforced flowing NaCl solutIon in bulk, gravitatIonal or electro convectIon supplies Ions from bulk toward the Membrane surface through a boundary layer. In a boundary layer formed on an anIon Exchange Membrane, the convectIon converts to migratIon and diffusIon and carries an electric current. In a boundary layer formed on a catIon Exchange Membrane, the convectIon converts to migratIon and carry an electric current. In a forced flowing solutIon in bulk, the boundary layer thickness is reduced and gravitatIon or electro convectIon is disappeared. An electric current is carried by diffusIon and migratIon on the anIon Exchange Membrane and by migratIon on the catIon Exchange Membrane. Ion transport in a boundary layer on the catIon Exchange Membrane immersed in a NaCl solutIon is more restricted comparing to the phenomenon on the anIon Exchange Membrane. This is due to lower counter-Ion mobility in the boundary layer and the restricted water dissociatIon reactIon in the Membrane. The water dissociatIon reactIon is generated in an Ion Exchange Membrane and promoted due to the increased forward reactIon rate constant. However, the current efficiency for the water dissociatIon reactIon is generally low. The intensity of the water dissociatIon is more suppressed in the strong acid catIon Exchange Membrane comparing to the phenomenon in the strong base anIon Exchange Membrane due to lower forward reactIon rate constant in the catIon Exchange Membrane. In the strong acid catIon Exchange Membrane, the intensity of electric potential is larger than the values in the strong base anIon Exchange Membrane. Accordingly, the stronger repulsive force is developed between Ion Exchange groups (SO _3 ^• groups) and co-Ions (OH^− Ions) in the catIon Exchange Membrane, and the water dissociatIon reactIon is suppressed. In the strong base anIon Exchange Membrane, the repulsive force between Ion Exchange groups (N^+(CH_3)_3 groups) and co-Ions (H^+ Ions) is relatively low, and the water dissociatIon reactIon is not suppressed. Violent water dissociatIon is generated in metallic hydroxides precipitated on the desalting surface of the catIon Exchange Membrane. This phenomenon is caused by a catalytic effect of metallic hydroxides. Such violent water dissociatIon does not occur on the anIon Exchange Membrane.
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Chapter 11 Limiting Current Density
Membrane Science and Technology, 2007Co-Authors: Yoshinobu TanakaAbstract:Publisher Summary This chapter discusses the limiting current density. When an electric current is passed through an Ion Exchange Membrane, salt concentratIon on a desalting surface of the Membrane is decreased due to concentratIon polarizatIon, and reduced to zero at the limiting current density. The chapter derives the limiting current density equatIon introduced from the Nernst–Planck equatIon. The chapter discusses the dependence of limiting current density on electrolyte concentratIon and solutIon velocity of a solutIon. ConcentratIon polarizatIon occurs in a boundary layer formed on the desalting surface of an Ion Exchange Membrane. The limiting current density is influenced by the solutIon flow in a desalting cell and Ionic transport in the boundary layer. Limiting current density of an electrodialyzer is influenced by the distributIon of solutIon flow in desalting cells. The chapter explains limiting current density of an electrodialyzer based on the limiting current density equatIon.
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irreversible thermodynamics and overall mass transport in Ion Exchange Membrane electrodialysis
Journal of Membrane Science, 2006Co-Authors: Yoshinobu TanakaAbstract:Abstract An Ion-Exchange Membrane electrodialysis phenomenon was presented by using phenomenological equatIon based on the irreversible thermodynamics. The overall mass transport equatIon was introduced based on the electrodialysis of seawater. The overall mass transport equatIon was joined to the phenomenological equatIon by setting both equatIons are equivalent each other. As the result of this process, the overall Membrane characteristics appeared in the overall mass transport equatIon (overall transport number λ, overall solute permeability μ, overall electro-osmotic permeability ϕ and overall hydraulic conductivity ρ) were expressed by the functIon of the irreversible Membrane pair characteristics appeared in the phenomenological equatIon (transport number t, solute permeability ω, electro-osmotic permeability β and hydraulic conductivity LP). λ, μ, ϕ, r (electric resistance) and W (water content) were expressed by the empirical functIon of ρ. ReflectIon coefficient was discussed by defining the pressure reflectIon coefficient σ and concentratIon reflectIon coefficient σ′. From the pressure dialysis of a KCl solutIon, σ of an Ion-Membrane was generally assumed to be 1. σ′ corresponded with the permselectivity between Ions and water molecules across an Ion-Exchange Membrane at just after electric current interruptIon (electric current switching off concept), and was expressed by the functIon of μ, ρ and logarithmic mean concentratIon C*. t, ω, β, LP, LPD (osmotic volume flow coefficient), LDP (ultrafiltratIon coefficient) and LD (Exchange flow parameter) included in the phenomenological equatIon were computed by applying the overall mass transport equatIon to electrodialysis experiments. The influence of concentratIon polarizatIon upon the overall Membrane characteristics measurement was negligibly small.
Maria A M Reis - One of the best experts on this subject based on the ideXlab platform.
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mercury removal from water streams through the Ion Exchange Membrane bioreactor concept
Journal of Hazardous Materials, 2014Co-Authors: Adrian Oehmen, Joao G Crespo, Maria A M Reis, Dario Vergel, Joana Fradinho, Svetlozar VelizarovAbstract:Mercury is a highly toxic heavy metal that causes human health problems and environmental contaminatIon. In this study, an Ion Exchange Membrane bioreactor (IEMB) process was developed to achieve Hg(II) removal from drinking water and industrial effluents. Hg(II) transport through a catIon Exchange Membrane was coupled with its bioreductIon to Hg(0) in order to achieve Hg removal from concentrated streams, with minimal productIon of contaminated by-products observed. This study involves (1) Membrane selectIon, (2) demonstratIon of process effectiveness for removing Hg from drinking water to below the 1ppb recommended limit, and (3) process applicatIon for treatment of concentrated water streams, where >98% of the Hg was removed, and the throughput of contaminated water was optimised through Membrane pre-treatment. The IEMB process represents a novel mercury treatment technology with minimal generatIon of contaminated waste, thereby reducing the overall environmental impact of the process.
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validatIon of the Ion Exchange Membrane bioreactor concept in a plate and frame module configuratIon
Process Biochemistry, 2012Co-Authors: Ana R Ricardo, Joao G Crespo, Svetlozar Velizarov, Maria A M ReisAbstract:Abstract The Ion Exchange Membrane bioreactor (IEMB) is a particular case of a Membrane-supported biofilm reactor, in which oxy-anIons, used as electron acceptors by an anoxic mixed microbial culture, are removed from a polluted water stream through an anIon-Exchange Membrane. The opposite side of this Membrane is used for the development of a biofilm, contacting a biocompartment, to which nutrients and chloride are fed as a source of “driving” counter-Ion. The applicability of a plate-and-frame IEMB module configuratIon, consisting of a series of Membranes, for the treatment of drinking water contaminated with nitrate and perchlorate, was evaluated. PermeatIon of carbon source across the Membrane to the treated water stream was avoided by a dedicated start-up procedure involving a gradual increase of ethanol feeding to the IEMB biocompartment. It was demonstrated that the biocompartment pH must be controlled not only to guarantee a complete perchlorate removal, but also to avoid precipitatIon of struvite on the Membrane surface, which provokes Membrane scaling and decreases the availability of nutrients for the biofilm. Under these conditIons, the IEMB was successfully operated maintaining both nitrate and perchlorate concentratIons in the treated water below their recommended levels for drinking water supplies.
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removal of heavy metals from drinking water supplies through the Ion Exchange Membrane bioreactor
Desalination, 2006Co-Authors: Adrian Oehmen, Maria A M Reis, Svetlozar Velizarov, R M C Viegas, Joao G CrespoAbstract:Arsenic (As) and mercury (Hg) are two highly toxic heavy metals that must be removed to very low levels in drinking water supplies. A novel treatment method for the removal of both compounds is the Ion Exchange Membrane bioreactor (IEMB) process, which incorporates pollutant transport through an Ion Exchange Membrane by Donnan dialysis, with biological removal of the pollutant. As detailed in this study, the IEMB process has a high potential for use in drinking water treatment systems, and offers numerous advantages over currently implemented processes, such as minimising the risk of secondary pollutIon of the drinking water.
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simultaneous removal of perchlorate and nitrate from drinking water using the Ion Exchange Membrane bioreactor concept
Water Research, 2006Co-Authors: Cristina T Matos, Joao G Crespo, Svetlozar Velizarov, Maria A M ReisAbstract:Abstract This work evaluates the feasibility of the Ion Exchange Membrane bioreactor (IEMB) concept for the simultaneous removal of perchlorate and nitrate from drinking water, when nitrate is present in the ppm range and perchlorate in the ppb range. The IEMB concept combines Donnan dialysis and simultaneous biological degradatIon of both pollutants. Membrane transport studies showed that Donnan dialysis is suitable for obtaining water with concentratIons of perchlorate and nitrate below the recommended levels. However, the pollutants were accumulated in a receiving stream, thus requiring additIonal treatment before disposal. On the other hand, the IEMB process operated with hydraulic retentIon times ranging from 1.4 to 8.3 h in the water compartment, proved to remove effectively perchlorate and nitrate while preserving the water compositIon with respect to other Ions, thus avoiding secondary contaminatIon of the treated water. For a polluted water stream containing 100 ppb of ClO 4 − and 60 ppm of NO 3 − , the concentratIons of both Ions in the treated stream were kept below the recommended levels of 4 ppb for ClO 4 − and 25 ppm for NO 3 − . The IEMB system was operated under ethanol limitatIon, but even under these conditIons, an increase of the perchlorate and nitrate concentratIons in the treated water was not observed for up to 6 days.
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removal of trace mono valent inorganic pollutants in an Ion Exchange Membrane bioreactor analysis of transport rate in a denitrificatIon process
Journal of Membrane Science, 2003Co-Authors: Svetlozar Velizarov, Maria A M Reis, Joao G CrespoAbstract:The Ion Exchange Membrane bioreactor (IEMB) uses a mono-anIon permselective Membrane as a barrier between a water stream, containing a target polluting anIon, and a biocompartment, containing a suitable driving counter-Ion for coupled counter-diffusIon of the target pollutant and a microbial culture capable of its bioreductIon to harmless product(s). A resistances-in-series trace counter-Ion approximatIon model, based on the Fick formalism and the Donnan equilibrium principle is proposed for analysis of the transport rate of dilute inorganic anIonic pollutants with relevance to drinking water treatment. Transport of co-Ions (catIons) is negligible due to their electrostatic repulsatIon (Donnan exclusIon) from the positively charged Membrane. The model is tested for a system, containing nitrate as the target pollutant and chloride as the driving bulk counter-Ion. The effect of the most important process variables on the target pollutant flux are assessed using the model, making possible the comparison between different IEMB process optIons, which can be quantified and used for process design. The impact of the bioconversIon reactIon on the mass transfer resistance to the target pollutant transport is also discussed.
Matthew M. Mench - One of the best experts on this subject based on the ideXlab platform.
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influence of Membrane equivalent weight and reinforcement on Ionic species crossover in all vanadium redox flow batteries
Membranes, 2017Co-Authors: Yasser Ashraf Gandomi, Doug S Aaron, Matthew M. MenchAbstract:One of the major sources of lost capacity in all-vanadium redox flow batteries (VRFBs) is the undesired transport (usually called crossover) of water and vanadium Ions through the Ion-Exchange Membrane. In this work, an experimental assessment of the impact of Ion-Exchange Membrane properties on vanadium Ion crossover and capacity decay of VRFBs has been performed. Two types of catIonic Membranes (non-reinforced and reinforced) with three equivalent weights of 800, 950 and 1100 g·mol−1 were investigated via a series of in situ performance and capacity decay tests along with ex situ vanadium crossover measurement and Membrane characterizatIon. For non-reinforced Membranes, increasing the equivalent weight (EW) from 950 to 1100 g·mol−1 decreases the V(IV) permeability by ~30%, but increases the area-specific resistance (ASR) by ~16%. This increase in ASR and decrease in V(IV) permeability was accompanied by increased through-plane Membrane swelling. Comparing the non-reinforced with reinforced Membranes, Membrane reinforcement increases ASR, but V(IV) permeability decreases. It was also shown that there exists a monotonic correlatIon between the discharge capacity decay over long-term cycling and V(IV) permeability values. Thus, V(IV) permeability is considered a representative diagnostic for assessing the overall performance of a particular Ion-Exchange Membrane with respect to capacity fade in a VRFB.
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coupled Membrane transport parameters for Ionic species in all vanadium redox flow batteries
Electrochimica Acta, 2016Co-Authors: Yasser Ashraf Gandomi, Matthew M. Mench, Douglas AaronAbstract:Abstract One of the major sources of capacity loss in all-vanadium redox flow batteries (VRFBs) is the undesired transport of active vanadium species across the Ion-Exchange Membrane, generically termed crossover. In this work, a novel system has been designed and built to investigate the concentratIon- and electrostatic potential gradient-driven crossover for all vanadium species through the Membrane in real-time. For this study, a perfluorosulphonic acid Membrane separator (NafIon® 117) was used. The test system utilizes ultraviolet/visible (UV/Vis) spectroscopy to differentiate vanadium Ion species and separates contributIons to crossover stemming from concentratIon and electrostatic potential gradients. It is shown that the rate of species transport through the Ion-Exchange Membrane is state of charge dependent and, as a result, interactIon coefficients have been deduced which can be used to better estimate expected crossover over a range of operating conditIons. The electric field was shown to increase the negative-to-positive transport of V(II)/V(III) and suppress the positive-to-negative transport of V(IV)/V(V) during discharge, with an inverse trend during charging conditIons. Electric-field-induced transport coefficients were deduced directly from experimental data.
