Influence of the nitrates in the anolyte on the mfc performance
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- INFLUENCE OF THE NITRATES IN THE ANOLYTE ON THE MFC PERFORMANCE Катерина Николова 1 , Силвия Лаврова 2 , Анатолий Ангелов 1 и Светлана Браткова 1
- ВЛИЯНИЕ НА СЪДЪРЖАНИЕТО НА НИТРАТИТЕ В АНОЛИТА ВЪРХУ МГК Катерина Николова 1 , Силвия Лаврова 2 , Анатолий Ангелов 1 , Светлана Браткова 1
- Katerina Nikolova 1 , Silvia Lavrova 2 , Anatoliy Angelov 1 and Svetlana Bratkova 1
- Figure 1. Laboratory-scaled installation of microbial fuel cell.
- h our pH Eh, mV
- Fig.ure Фигура 1 . pH dynamics in the anodic chamber of MFC at the organic compounds oxidation in the presence or absence of nitrates
- Фигура Fig.ure 2. Dynamics of nitrates concentration in the anodic chamber of MFCИзменение на концентрацията на нитрати в анодната област.
- Fig.ureФигура 3. Dynamics of the permanganate index in the anodic chamber of MFC Динамика на перманганатната окисляемост в анодната област на MFC1
- Фигура Fig.ure 4. Voltage and power density of MFC with nutrient medium without nitratesНапрежение и плътност на мощността при работа на MFC 1 с хранителна среда G1 без нитрати
- 1.2. Изследване на влиянието на нитратите върху протичането на процеса на окисление на органичните вещества в анодната област на MFC 1 при използване на реални отпадъчни води.
- Fig.ure 6. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium without nitrates.
- Fig.ure 7. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium with nitrates
- Fig.ure 8. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium with and without nitrates at a temperature 20 0 C
| ГОДИШНИК НА МИННО-ГЕОЛОЖКИЯ УНИВЕРСИТЕТ “СВ. ИВАН РИЛСКИ”, Том 57, Св. II, Добив и преработка на минерални суровини, 2014
ANNUAL OF THE UNIVERSITY OF MINING AND GEOLOGY “ST. IVAN RILSKI”, Vol. 57, Part ІI, Mining and Mineral processing, 2014 INFLUENCE OF THE NITRATES IN THE ANOLYTE ON THE MFC PERFORMANCE Катерина Николова1, Силвия Лаврова2, Анатолий Ангелов1 и Светлана Браткова1 Katerina Nikolova 1, Silvia Lavrova 2, Anatoliy Angelov 1, Svetlana Bratkova 1 1 UMG “St. Ivan Rilski”, Sofia 2 UCTM, Sofia ABSTRACT. Microbial Fuel Cells (MFCs) are considered as one of the alternative energy sources from renewable materials. For the purpose of this study it was designed a two-chambered MFC, as it was used membrane type CMI-7000S. In the anodic chamber were treated waters, containing organic compounds in high concentration in presence or in absence of nitrates. The cathodic chamber was filled up with 100 mM K3[Fe(CN)6] in 67 mM phosphate buffer with pH 7.0. It was found that the presence of nitrates in the waters resulted in a rapid consumption of a part of the donors of electrons, i.e. the denitrification had a negative effect on the performance of the fuel cell. On the other hand, this process had resulted in a higher rate of oxidation of organic substances in water and their removal of nitrate nitrogen. The data obtained showed that a significant number of physico-chemical, technological and microbiological factors had an influence on the efficiency of the process. ВЛИЯНИЕ НА СЪДЪРЖАНИЕТО НА НИТРАТИТЕ В АНОЛИТА ВЪРХУ МГК Катерина Николова1, Силвия Лаврова2, Анатолий Ангелов1, Светлана Браткова1 1 МГУ “Св. Иван Рилски”, София 2 ХТМУ, София РЕЗЮМЕ.: Микробните горивни клетки (МГК) се считат за един от алтернативните източници на енергия от възобновяеми суровини. За целите на това проучване беше проектирана двукамерна МГК, като беше използвана мембрана тип CMI-7000S. В анодната камера се третираха води с висока концентрация на органични съединения, в присъствие или в отсъствие на нитрати. Катодната камера беше запълнена с 100 mМ K3 [Fe (CN) 6] в 67 mМ фосфатен буфер с рН 7,0. Беше установено, че наличието на нитрати във водите води до бърза консумация на част от донорите на електрони, т.е. денитрификацията оказва негативно влияние върху горивната клетка. От друга страна, този процес доведе до по-висока степен на окисление на органичните съединения във водата и тяхното пречистване от нитратен азот. Получените данни показват, че значителен брой от физико-химични, технологични и микробиологични фактори имат влияние върху ефективността на процеса. Katerina Nikolova 1, Silvia Lavrova 2, Anatoliy Angelov 1 and Svetlana Bratkova 1 1 UMG “St. Ivan Rilski”, Sofia 2 UCTM, Sofia ABSTRACT: Microbial Fuel Cells (MFCs) are considered as one of the alternative energy sources from renewable materials. For the purpose of this study it was designed a two-chambered MFC, as it was used membrane type CMI-7000S. In the anodic chamber were treated waters, containing organic compounds in high concentration in presence or in absence of nitrates. The cathodic chamber was filled up with 100 mM K3[Fe(CN)6] in 67 mM phosphate buffer with pH 7.0. It was found that the presence of nitrates in the waters resulted in a rapid consumption of a part of the donors of electrons, i.e. the denitrification had a negative effect on the performance of the fuel cell. On the other hand, this process had resulted in a higher rate of oxidation of organic substances in water and their removal of nitrate nitrogen. The data obtained showed that a significant number of physico-chemical, technological and microbiological factors had an influence on the efficiency of the process. Introduction Nitrogen is one of the key containments in wastewaters because its overload can cause eutrophication of a water bodies [(Camargo, 2006Alonso. Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment. Environ Int 2006;32:831–49]). Also the groundwaters areis at risk of contamination pollution by nitrates coming from agriculture and wastewater discharges. Likewise, tThe municipal landfill leachates are often with high nitrate concentration. The nitrate pollution is regarded as one of the serious environmental problems and is significantly affected by European legislation - the Nitrates Directive (91/767/EU), the Water Framework Directive (2000/60/EC) and the Groundwater Directive (2006/118/EC) [(Puig, Coma]). Microbial fuel cells (MFCs) based on the process of microbial dissimilative nitrate reduction (denitrification) offers the opportunity of simultaneous electricity generation and nitrates removal from influents. The process is typically performed in the anodic area of the fuel elements, and it can be combined with a chemical or other biological process in the cathodic chamber. Generally, during a continuous operation of the biological fuel cell, an electroactive biofilm is forming on the anodic surface or in the space around it. On the other hand, the classical design of MFCs (sandwich-type) does not create the optimal conditions for the development of the microflora, as they occure in the bioreactors with immobilized biomass. The main objective in this study is to test different technological options of implementation of the process of classical organic compounds oxidation denitrification in the anodic chamber of MFC for waters with high nitrate concentrations.
The microbial fuel cell has beenwas designed in 2 different volumes, cathodic and anodic chambers, disposed one inside the other and separated by a cation exchange membrane. The volume of the anodic chamber with the corresponding storage tank wais 0.65 dm3. Anodic area was inoculated with activated sludge from Wastewater Treatment Plant Sofia. The volume of the cathodic section together with the second buffer tank is 0.9 dm3. To separate the anode from the cathode space is used Cation Exchange Membrane type CMI-7000S (Membrane International Inc.) with surface of 0.0008 m2. As the electrodes are used graphite rods with a diameter of 8 mm and a length of 10 cm.
The volume of the cathodic section together with the second buffer tank was 0.9 dm3. To separate the anode from the cathode space was used Cation Exchange Membrane type CMI-7000S (Membrane International Inc.) with surface of 0.0008 m2. As the electrodes were used graphite rods with a diameter of 8 mm and a length of 10 cm.  
Figure 1. Laboratory-scaled installation of microbial fuel cell. 1 and 2 – feeding solutons; 3 and 4 – buffer tanks; 5 - recirculating pumps; 6 – anodic chamber of MFC; 7 – cathodic chamber of MFC; 8 - load circuit of the fuel cell; 9 – Potentiostat connected with PC .
The volume of the cathodic section together with the second buffer tank wais 0.9 dm3. To separate the anode from the cathode space wais used Cation Exchange Membrane type CMI-7000S (Membrane International Inc.) with surface of 0.0008 m2. As the electrodes arewere used graphite rods with a diameter of 8 mm and a length of 10 cm. During these series of laboratory investigations there were used synthetic solutions (media for heterotrophic bacteria). In the anodic area In thisof the installation in the anodi area were treated water solutions containing high concentrations of organic compounds in the presence and absence of nitrates.. During the serie of laboratory investigations were used synthetic solutions (media for heterotrophic bacteria) The culture medium for heterotrophic bacteria containeds 2.5 g/l glucose, 0.5 g/l peptone, 1.0 g/l K2HPO4, 0.2 g/l CaCl2, 2.0 g/l MgSO4x7H2O. The nitrates weare added in the form of KNO3. The catholyte in the cathodic chamber wais a solution of 100 mM K3[Fe(CN)6] in 67 mM phosphate buffer with pH 7.0. The final electron acceptor wais oxygen in air, which in reduction together with the protons located in cathodic space, formeds water. For this purpose, there wais an opportunity of cathode chamber aeration by a pump with a flow rate of 0,15 dm3/60s. pH, Eh and mV were measured in some certain points of laboratory installation. The same places weae sampled for spectrophotometric determination of and nitrites. Electric parameters of MCF weae measured with a portable digital multimeter Keithley Model-175. A precise potentiometer with maximum value of 12.0 k wai used for measurement of the external resistances. For the establishing of the system electrochemical behavior was used a potentsiostat - ACM 3 connected to PC for reporting and analysis of the accumulated data. Какъв е потенциостатът? Results and discussion It was conducted an investigation of the impact of nitrates on the performance of the oxidation process of organic compounds in the anodic chamber of the MFC using a modified culture medium for heterotrophic bacteria. Table 1 presents data for some parameters for the use of a nutrient medium for culturing heterotrophic bacteria containing glucose - 2,5 g/l and peptone - 0,5 g/l with no added nitrates. In this mode of operation the microbial fuel cell works like a standard fuel cell. The oxidation of organic compounds in the nutrient medium takes place into the anodic chamber. The variation of permanganate index (PI) provides insight into the dynamics of this process. In the cathodic area is achieved a reduction of ferricyanide to ferrocyanide. Таble 1. MFC performance at a continuous mode of cultivation with a modified nutrient medium without nitrates
Table 2 presents data on the same parameters in the anodic area using the same medium in which are added nitrates with an initial concentration of 1 g/l. From Figure 2 it can be seen that the process of denitrification flows at a high rates – 88 - 103 mg NO3-/l.h. Table 2 presents data on the same parameters in the anodic area using the same medium in which are added nitrates with an initial concentration of 1 g/l. From Figure 2 it can be seen that the process of denitrification flows at a high rates - 88-103 mg NO3- / l.h. Table 2.
MFC performance at a continuous mode of cultivation with a modified nutrient medium with 1 g/l nitrates
8-103 mg NO3- /lh. Tables 1, 2 and Figure 1 show the increase of pH in the anodic chamber. This increase is much more significant when the process of denitrification occursОт таблици 1 и 2, както и от графика 1 се вижда, че с времето рН в анодната област нараства, като това изменение е по-значително при протичането на процеса денитрификация..  
Fig.ureФигура 1. pH dynamics in the anodic chamber of MFC at the organic compounds oxidation in the presence or absence of nitratesДинамика на рН в анодната област при окисление на органичните вещества в отсъствие и присъствие на нитрати  
Фигура Fig.ure 2. Dynamics of nitrates concentration in the anodic chamber of MFCИзменение на концентрацията на нитрати в анодната област. The process of denitrification in the microbial fuel cell is accompanied by a higher consumption of the organic compounds (Figure 3). From the presented data it can be concluded that the presence of nitrates in waters containing high concentrations of organic compounds, treated in the anodic chamber of a classic microbial fuel cell, will result in the consumption of the electron donor, i.e., the denitrification has a negative effect on the MFC performance. On the other hand, this process resulted in a higher rate of oxidation of organic compounds in waters and the nitrates removal.  Протичането на денитрификация в микробната горивна клетка се съпровожда с по-висока консумация на органични съединения ( фигура 3). От представените данни може да бъде направен извода, наличието на нитрати във води, съдържащи високи концентрации органични съединения, третирани в анодната област на класическата микробна горивна клетка ще доведат до консумация на част от донора на електрони, т.е. денитрификацията има негативен ефект върху работата на горивния елемент. От друга страна, този процес има като резултат по-висока скорост на окисление на органичните вещества във водите, както и пречистването им от нитратен азот.
Fig.ureФигура 3. Dynamics of the permanganate index in the anodic chamber of MFC Динамика на перманганатната окисляемост в анодната област на MFC1 Figures 4 and 5 show the efficiency of the MFC performance with the two mentioned above media in the anodic chamberФигури 4 и 5 дават представа за ефективността на горивния елемент.   
Фигура Fig.ure 4. Voltage and power density of MFC with nutrient medium without nitratesНапрежение и плътност на мощността при работа на MFC 1 с хранителна среда G1 без нитрати   
Fig.ure 5. Voltage and power density of MFC with nutrient medium with nitrates in initial concentration 1 g/lФигура 5. Напрежение и плътност на мощността при работа на MFC 1 с хранителна среда G1 с нитрати It is От получените резултати се вижда, че в присъствие на нитрати спада плътността на мощността W/m2 в диапазона на плътност на тока 44 – 118 mA/m2. obvious from the obtained results that in the presence of nitrates the power density decreased in the range of current density from about 40 to 120 mA/m2. In another series of investigations there was studied the influence of temperature on the MFC performance. It was established a significant impact of temperature on the basic electrochemical parameters. 1.2. Изследване на влиянието на нитратите върху протичането на процеса на окисление на органичните вещества в анодната област на MFC 1 при използване на реални отпадъчни води. В микробна горивна клетка 1 е направен експеримент с реални отпадъчни води (инфилтрат от депо за ТБО). Изследвани са три варианта: нетретиран инфилтрат, нитрифициран инфилтрат и нетретиран инфилтрат, към който са добавени нитрати в концентрация 1 g/l. 
Фигура 6. Изменение на напрежението в зависимост от плътността на тока при работа на горивния елемент с реални отпадъчни води 
Фигура 7. Изменение на плътността на мощността в зависимост от плътността на тока при работа на горивния елемент с реални отпадъчни води От представените резултати на фигури 6 и 7 се вижда , че има възможност за включване на микробен горивен елемент в технологични схеми за третиране на инфилтрати от депа за ТБО. Получените данни обаче са недостатъчни, за пълно охарактеризиране на процесите в анодната област, тъй като върху тях оказват влияние значителен брой физико-химични, технологични и микробиологични фактори. Повишаването на плътността на мощността при работа на микробната горивна клетка с инфилтрат, към който е добавен KNO3 като източник на нитрати в концентрация 1 g/l може да се дължи на изменение на йонната сила на разтвора в анолита, както и на евентуално преминаване на катионите на калия през мембраната. Използваната мембрана е катионопропусклива, но не е селективна по отношение на отделните катиони, т.е. освен протони е възможно да пропуска и други катиони. Най-висока плътност на мощността се получава при използване на нитрифициран инфилтрат. 
Fig.ure 6. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium without nitrates. Regarding the influence of temperature there were conducted experiments at temperatures of 10 to 300C. In both variants of the used anolyte, shown at Figure 6 and 7, was established an improvment of the the electrochemical performance of the fuel cell, as the area of the cyclic VA characteristic increased of approximately 15 to 20% at a temperature of 300C in comparison with that at 100C. 
Fig.ure 7. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium with nitrates ing thwere conducted experiments at temres of was established improe the electcal pero 20% at rature f 300C in compaison with 0C П Significant influence on the electrochemical performance of the fuel cell had the chemical composition of the anolyte. In this regard were conducted2 types of tests - with nutrient media for heterotrophc bacteria in absence or presence of nitrates, as the concentration of the nitrate ions in the second option was 1g/l. In these experiments were showing changes in the shape of the surface area of the cyclic voltammetric characteristics. The presence of nitrates affected the conductivity of the anolyte, which in turn influenced the maximum values of the current through the MFC in forward and reverse direction (Fig. 8). о отношение влиянието на температурата бяха проведени експерименти при температури 10 и 30 oC. И при двата варианта на използваните анолити показати на Фиг 6 и 7. се установява подобряване на електрохимичните показатели на горивната клетка, като площта цикличната VA характеристика нараства с около от 15 до 20 % при температура 30 oC в сравнение с 10 oC.  
Fig.ure 8. Influence of temperature on the surface area of the cyclic voltammetric characteristics with a medium with and without nitrates at a temperature 200C Съществено влияние върху електрохимичните характеристики на горивния елемент оказва хим. състав на анолита. В тази насока бяха тестове с 2 варианта – при хранителна среда K4 без нитрати и хранителна среда K4 с нитрати, като концентрацията на NO3 при втория вариант беше около.... (1g/l ?). при тези опити се установява промяна на формата на цикличната VA характериктика, като присъствието на нитрати оказва влияние върху проводимоста на анолита, което пък от своя страна оказва влияние и върху максималните стойности на тока през MFC в права и обратна посока(фиг. 8). Conclusions It is obvious from the presented results that there is a possibility for the inclusion of MFC in technological schemes for the treatment of wastewaters with high concentrations of organic matter such as leachate from municipal solid wastes landfills. The obtained data, however, is insufficient for the complete characterizaion of the processes in the anodic chamber, as they are influenced by a significant number of physico-chemical, microbiological and technological factors. The increase of the power density during the operation of the microbial fuel cell with a solution, to which was added KNO3 as a source of nitrates at a concentration of 1 g/l NO3, may be due to a change in the ionic strength of the solution in the anolyte, as well as to the possible transition of cations of potassium trough the membrane. The used membrane was cationexchange, but not selective with respect to different cations, i.e. apart from protons it is possible to let pass and other cations. атъчни, за пълно охарактеризиране на процесите в анодната област, тъй като върху тях оказват влияние значителен брой физико-химични, технологични и микробиологични фактори. Повишаването на плътността на мощноста е катионопропусклива, но не е селективна по отношение на ост на мощността се получава при използване на нитрифициран инфилтрат. Refferences Anatoliy Angelov, Svetlana Bratkova, Alexandre Loukanov, (2013), Microbial fuel cell based on electroactive sulfate-reducing biofilm, Energy Conversion and Management, Vol.67, pp 283-286, 2013, ISSN: 0196-8904. Balows A., Trilper H. G., Dworkin M., Harder W., and Schleifer K. H. (Eds.), The Prokaryotes, 2nd ed. Springer, New York, 1992. Camargo, Alonso. Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment. Environ Int 2006;32:831–49 Farabegoli G., Chiavola A., Rolle E., The biological aerated filter (BAF) as alternative treatment for domestic sewage. Optimization of plant performance, J. Hazardous Materials, 171, 2009, 1126 – 1132. Guerrero-Rangel, N., Rodriguez-de la Garza, J. A., Garza-Garcia, Y., Rios-Gonzalez, L. J., Sosa- Santillan, G. J., de la Garza-Rodriguez, I. M., Martinez-Amador, S. Y., Rodriguez-Garza M. M., & Rodriguez-Martinez, J. (2010), Comparative Study of Three Cathodic Electron Acceptors on the Performance of Medatiorless Microbial Fuel Cell. International Journal of Electrical and Power Engineering Year, 4(1), 27- 31. Habermann, W., Pommer, E.-H.(1991), Appl. Microbiol. Biotechnol. 35, 128–133. Ieropoulos, I., Greenman, J., Melhuish, C., and Hart, J. (2005). Comparative study of three types of microbial fuel cell. Enzyme Technology, 238-245. Katerina Nikolova, Anatoliy Angelov, Svetlana Bratkova and Petia Genova, 2013, Influence of various factors on the efficiency of MFC based on the process of microbial dissimilatory sulfate-reduction, "Confereng 2013”, Tg-Jiu, Romania. Puig, Sebastià, Coma, Marta, Desloover, Joachim, Boon, Nico, Colprim, Jesús and Balaguer, M. Dolors. Autotrophic Denitrification in Microbial Fuel Cells Treating Low Ionic Strength Waters, Environ. Sci. Technol., 2012, 46 (4), pp 2309–2315 Rabaey, K., & and Verstraete, W. (2005), Microbial fuel cells: novel biotechnology for energy generation. Trends in Biotechnology, 23,291-298. Renoua S., Givaudan J., Poulain S., Dirassouyan F., Moulin P., Landfill leachate treatment: Review and opportunity, Journal of Hazardous materials 150, 2008, 468-493. Zhao, F., Rahunen, N., Varcoe, J. R., Chandra, A., Avignone-Rossa, C., Thumser, A. E., & Slade, R. C. T. (2008), Activated Carbon Cloth as Anode for Sulfate Removal in a Microbial Fuel Cell. Environ. Sci. Technol., 42(13), 4971- 4976. The article has been recommended for publication by department “Engineering Geoecology”. Anatoliy Angelov, Svetlana Bratkova, Alexandre Loukanov, (2013), Microbial fuel cell based on electroactive sulfate-reducing biofilm, Energy Conversion and Management, Vol.67, pp 283-286, 2013, ISSN: 0196-8904. Balows A., Trilper H. G., Dworkin M., Harder W., and Schleifer K. H. (Eds.), The Prokaryotes, 2nd ed. Springer, New York, 1992. Guerrero-Rangel, N., Rodriguez-de la Garza, J. A., Garza-Garcia, Y., Rios-Gonzalez, L. J., Sosa- Santillan, G. J., de la Garza-Rodriguez, I. M., Martinez-Amador, S. Y., Rodriguez-Garza M. M., & Rodriguez-Martinez, J. (2010), Comparative Study of Three Cathodic Electron Acceptors on the Performance of Medatiorless Microbial Fuel Cell. International Journal of Electrical and Power Engineering Year, 4(1), 27- 31. Habermann, W., Pommer, E.-H.(1991), Appl. Microbiol. Biotechnol. 35, 128–133. Ieropoulos, I., Greenman, J., Melhuish, C., and Hart, J. (2005). Comparative study of three types of microbial fuel cell. Enzyme Technology, 238-245. Rabaey, K., & and Verstraete, W. (2005), Microbial fuel cells: novel biotechnology for energy generation. Trends in Biotechnology, 23,291-298. Zhao, F., Rahunen, N., Varcoe, J. R., Chandra, A., Avignone-Rossa, C., Thumser, A. E., & Slade, R. C. T. (2008), Activated Carbon Cloth as Anode for Sulfate Removal in a Microbial Fuel Cell. Environ. Sci. Technol., 42(13), 4971- 4976. Каталог: sessions sessions -> Изследване чистотата на слънчогледово масло за производство на експлозиви anfo sessions -> Laser “Raman” spectroscopy of anglesite and cubanite from deposit “Chelopech” Dimitar Petrov sessions -> Св иван рилски sessions -> Modeling of sessions -> Управление на риска от природни бедствия sessions -> Oценка на риска от наводнениe в елховското структурно понижение в района на гр. Елхово красимира Кършева sessions -> Гравиметрични системи използвани в република българия и оценка точността на системи igsn-71 и unigrace при точки от гравиметричните и мрежи sessions -> Toxicological assessment of photocatalytically destroyed mixed azo dyes by chlorella vulgaris sessions -> Field spectroscopy measurements of rocks in Earth observations Изтегляне 166.09 Kb. Сподели с приятели:
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