Search

Nüfus artışı ve endüstriyel gelişme nedeniyle küresel enerji ihtiyacı ve enerji tüketimi endişe verici bir oranda artmaktadır. Artan enerji talebini karşılamak için alternatif yenilenebilir enerji kaynaklarına ihtiyaç vardır. Mikrobiyal yakıt hücreleri (MYH’ler) atıklardan direk elektrik üretimi ve eş zamanlı olarak atıkların arıtımının gerçekleştirilmesinden dolayı yenilenebilir enerji üretimi açısından son yıllarda oldukça dikkat çekmektedir. Diğer taraftan mikroalgler, bünyelerinde enerji değeri yüksek bileşikleri depolaması ve fotosentez yoluyla CO2’yi uzaklaştırarak oksijen üretmesi nedeniyle yenilenebilir enerji üretimi alanında ve çevresel uygulamalarda ön plana çıkmıştır. Son yıllarda mikroalglerin MYH sistemlerinde kullanılması ile mikroalglerin MYH’nin verimliliğini artırabildiği ve biyoelektrik üretimi için uygun maliyetli ve sürdürülebilir bir yaklaşım sağlayabildiği anlaşılmıştır. Mikroalg tabanlı MYH’ler (MT-MYH) diğer MYH sistemlerine kıyasla daha fazla sürdürülebilir olmasına rağmen, şu an literatürdeki veriler yetersizdir. Bu sistemlerin verimliliğini artırmak ve büyük ölçekli uygulamaların yaygınlaşabilmesi için bu sistemler üzerine yapılan araştırmaların arttırılması gerekmektedir. Bu çalışmada sürdürülebilir bir biyoenerji üretimi için mikroalg tabanlı MYH’ler detaylı bir şekilde analiz edilerek ele alınmıştır.

This study presents research results on electricity production from waste activated sludge using MFCs during stabilization process. Different MFC configurations equipped with various electrodes were used. Voltage measurements were continuously done during 35 days of MFC operation. Experimental results showed that bioelectricity generation was linked to volatile solids (VS) and protein reductions as a fraction of extracellular polymeric substances (EPS). Double chamber MFC reactor equipped with graphite electrodes had better power and current densities as 312.98 mW/m(2) and 39.07 mu A/cm(2) while single chamber MFC equipped with titanium electrodes revealed better power and current densities as 97.60 mW/m(2) and 17.63 mu A/cm(2), respectively. Molecular results indicated that power outputs of MFCs effected by diverse microbial communities in anode biofilms. Although organic matter degradation is reported as 35%-55% VS reduction for digesters, this research provided a promising approach for sludge stabilization with enhanced degrading of organic matters up to 75% by using MFCs. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this study, the Cladophora sp. is used to provide oxygen to the cathode of the photosynthetic biocathode membrane-less microbial fuel cell (PB-MLMFC). Non-aerated (NA-MLMFC) and mechanically-aerated (MA-MLMFC) MLMFCs are operated under similar operating conditions to evaluate the performance of PB-MLMFC with the presence of Cladophora sp. The PB-MLMFC exhibits the highest dissolved oxygen (DO) concentration, which results in a more efficient oxygen reduction reaction and a significant improvement in the electricity generation performance. The maximum power density of PB-MLMFC is 619.1 mW m

Bu çalışmada, grafen kaplı nikel-titanyum (NiTi) alaşımı üretilerek mikrobiyal yakıt hücresinde (MYH) anot elektrotu olarak kullanılmıştır. Çalışmada çift bölmeli bir MYH reaktörü sürekli modda işletilmiş ve elektrik üretim performansı detaylı bir şekilde araştırılmıştır. MYH reaktörünün ürettiği maksimum güç yoğunluğu 2043 mW/m2 olarak elde edilmiştir. Sistemin toplam iç direnci 437.7 W olarak ölçülmüştür. İşletme süresi sonunda anot elektrotu yüzeyinden alınan SEM görüntülerinde biyofilm yapısında genellikle yuvarlak şekilli mikroorganizmaların mevcut olduğu tespit edilmiştir. Biyofilm numunesine uygulanan PCR-DGGE analizleri elektrot yüzeyinde Shewanella oneidensis ve Pseudomonas aeruginosa gibi elektrik üretiminde etkin mikrobiyal türlerin mevcut olduğunu göstermiştir.

Alg biyokütlesi yüksek organik içeriğinden dolayı mikrobiyal yakıt hücreleri (MYH) için eşsiz substrat kaynaklarından biridir. Fakat alg hücre duvarının kompleks yapısı biyolojik parçalanabilirliğini önemli ölçüde kısıtlamaktadır. Bu çalışmada farklı konsantrasyonlarda (5-30 ml/L aralığında) hidrojen peroksit (H2O2) kullanılarak alg biyokütlesine ön işlem uygulanmış ve MYH sisteminde elektrik üretim performansı araştırılmıştır. MYH’de maksimum güç yoğunluğu (244.64 mW/m2) 25 ml/L H2O2 konsantrasyonunda ön işlem uygulanmış alg biyokütlesi ile elde edilmiştir. Elde edilen maksimum güç miktarı kontrol reaktörüne (41.16 mW/m2) kıyasla yaklaşık olarak altı kat daha yüksektir. Moleküler analizler, ön işlem uygulanmış alg biyokütlesinin kullanıldığı MYH reaktöründe (MYH-A) b-proteobacteria grubuna ait bakteriyel türlerin oranının kontrol reaktörüne (MYH-K) kıyasla %10 arttığını göstermiştir. Ayrıca döngüsel voltametri (CV) sonuçları, MYH-A reaktörlerindeki anot biyofilminin MYH-K reaktörünün anot biofilmine kıyasla daha yüksek bir elektroaktiviteye sahip olduğunu göstermiştir. Çalışma sonuçları, H2O2’nin alg biyokütlesinin biyolojik olarak parçalanmasını desteklemek ve MYH’nin elektrik üretim performansını iyileştirmek için etkili bir ön işlem yöntemi olduğunu göstermiştir.

Bu çalışmada laboratuvar ölçekli bir biyofotovoltaik hücre (BFVH) kullanılarak Chlorella Vulgaris mikroalginin elektrik üretim kapasitesi araştırılmıştır. BFVH’de anot materyali olarak kalay oksit kaplı bakır mesh elektrot, katot materyali olarak ise platin kaplı titanyum mesh elektrot kullanılmıştır. BFVH’de üretilen maksimum güç yoğunluğu 142,28 mW/m2 olarak elde edilmiştir. Nyquist analizi sonucunda anot biyofilm direncinin 0,74 Ω olduğu belirlenmiştir. BFVH’nin işletme süresi sonunda anot elektrotu yüzeyinden alınan SEM görüntülerinde yoğun bir biyofilm yapısının mevcut olduğu tespit edilmiştir. Elde edilen sonuçlar, BFVH’nin elektrik üretim performansının literatür değerleri ile kıyaslanabilir düzeyde olduğunu göstermiştir.

The adverse effect of tetracycline antibiotics on microbial activity is one of the serious risks for the biologic wastewater treatment process. The microbial fuel cells (MFCs) are a promising technology for wastewater treatment and renewable power generation process. For this reason, the investigation of the inhibition effect of the tetracyclines on the MFCs is essential for reducing damage on the environment. This paper focused on the performance of MFCs under different antibiotic concentrations at the range of 0.25–50 mg/L. The power generation performance, microbial community and biofilm characteristics (morphology, resistance and viability) of MFCs were investigated in detail. The results indicated that the increase in the antibiotic concentration significantly affected the MFC performance and microbial community. A modified non-competitive inhibition model was used to predict the inhibition effect of tetracycline antibiotics on the MFCs.

This study aims to reduce membrane fouling in membrane photobioreactor (MPBR) through the quorum quenching (QQ) strategy. For this purpose, the QQ beads (immobilized Rhodococcus sp. BH4) were added to the MPBR, and antifouling ability was evaluated in consideration of the changes in transmembrane pressure (TMP), extracellular polymeric substance (EPS), microbial community, and cake layer morphology on the membrane surface. The results showed that the TMP of control MPBR (MPBR-C) reached 818 mbar and 912 mbar on the operation hours of 35 and 170, while the TMP of experimental MPBR (MPBR-QQ) was only 448 mbar and 676 mbar, respectively. The QQ strategy effectively reduced the EPS content in MPBR. The microscopic observations indicated that the QQ diminished the cake layer formation and pore-blocking on the membrane surface. Comparisons of 16S and 18S gene communities revealed minor differences between bacterial and eukaryotic species in MPBRs at phylum and class levels.

Özet Hücre dışı polimerik maddeler (HPM), mikroorganizmalar tarafından salgılanan, hücre parçalanmasından üretilen yüksek moleküler ağırlıklı kompleks bir polimer karışımından ve atıksudan adsorbe edilen organik maddelerden oluşmaktadır. HPM’nin başlıca bileşenleri (karbonhidratlar, proteinler, hümik maddeler ve nükleik asitler) ve karakteristikleri (adsorpsiyon, biyolojik parçalanabilirlik ve hidrofiliklik/hidrofobiklik) mikrobiyal agregaların özelliklerini önemli ölçüde etkilemektedir. HPM, çok kompleks özelliklere sahip olduğundan biyolojik atıksu arıtma tesislerindeki rollerini tam olarak anlamak için çok çalışma yapılması gerekmektedir. Bu çalışmada; HPM’nin bileşenleri ve dağılımı, HPM’nin karakteristikleri, HPM üretimine etki eden faktörler, HPM ekstraksiyonu, HPM analiz yöntemleri, mikrobiyal agregalarda HPM’nin rolü başlıkları altında HPM ayrıntılı olarak verilmiştir.

Anode biofilm thickness is a key point for high and sustainable power generation in microbial fuel cells (MFCs). Over time, the formation of a thicker biofilm on anode electrode hinders the power generation performance of MFC by causing a longer electron transfer path and the accumulation of undesirable components in anode biofilm. To overcome these limitations, we used a novel strategy named quorum quenching (QQ) for the first time in order to control the biofilm thickness on the anode surface by inactivation of signal molecules among microorganisms. For this purpose, the isolated QQ bacteria (Rhodococcus sp. BH4) were immobilized into alginate beads (20, 40, and 80 mg/10 ml sodium alginate) and added to the anode chamber of MFCs. The MFC exhibited the best electrochemical activity (1924 mW m−2) with a biofilm thickness of 26 μm at 40 mg Rhodococcus sp. BH4/10 ml sodium alginate. The inhibition of signal molecules in anode chamber reduced the production of extracellular polymeric substance (EPS) by preventing microbial communication amonganode microorganisms. Microscopic observations revealed that anode biofilm thickness and the abundance of dead bacteria significantly decreased with an increase in Rhodococcus sp. BH4 concentration in MFCs. Microbiome diversity showed an apparent difference among the microbial community structures of anode biofilms in MFCs containing vacant and Rhodococcus sp. BH4 beads. The data revealed that the QQ strategy is an efficient application for improving MFC performance and may shed light on future studies.

In the last years, increasing attention has been paid on the presence of antibiotics in aqueous environments due to their ecological damage and potential adverse effects on organisms. Membrane biofilm reactors (MBfR) have been gained a significant popularity as an advanced wastewater treatment technology in removing of organic micro-pollutants. In this study, the performance of H-2-MBfR for simultaneous removal of nitrate and chlortetracycline, formation of transformation products and community analysis of the biofilm grown on the gas permeable hollow fiber membranes was evaluated by considering effect of the hydraulic retention time, surface loadings of target pollutants and H-2 pressure. The results showed that the simultaneous chlortetracycline (96%) and nitrate removal (99%) took placed successfully under the conditions of 5 h HRT and 2 psi H-2 pressure. It has been determined that the main elimination process was biodegradation and Betaproteobacteria species was responsible for chlortetracycline degradation. (C) 2016 Elsevier B.V. All rights reserved.

Nitinols (Nickel-titanium alloys) have a good electrical conductivity and biocompatibility with human tissue and bacteria and, therefore, can be effectively used as an anode material in bioelectrochemical systems. This paper aimed to use nitinols (at different Ni/Ti ratios) as an anode material for microbial fuel cells (MFCs) in order to achieve higher power density. The maximum power densities of the MFCs using NiTi-1, NiTi-2, and NiTi-3 electrodes were 555 mW/m2, 811 mW/m(2), and 652 mW/m(2), respectively. More bacterial adhesion was observed on the NiTi-2 electrode. Electrochemical impedance spectroscopy (EIS) results showed low charge transfer resistance at MFCs fabricated with NiTi. The biofilm observations indicate that bacterial attachment is better with NiTi-2 as compared with that on NiTi-1 and NiTi-3. The resulting mesopore and macropore rich structure significantly promote microbial colonization, enabling formation of compact electroactive biofilms with additional benefit from the excellent biocompatibility and chemical stability of NiTi-2. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) results indicated that five groups of bacteria were the dominant phyla in the MFCs: environmental samples, b-proteobacteria, g-proteobacteria, d-proteobacteria, and CFB group bacteria. The high biocompatibility, electrical conductivity and stability of nitinols make them a more attractive anode material for MFCs. (C) 2019 Elsevier B.V. All rights reserved.

Tetracycline (TC) in aqueous environment could be reductively degraded by using a hydrogen-based membrane biofilm reactor (H-2-MBfR) under denitrifying conditions as it provides an appropriate environment for the antibiotic-degrading bacteria in biofilm communities. This study evaluates the performance of H-2-MBfR for simultaneous removal of nitrate and TC, formation of degradation products of TC, and community analysis of the biofilm grown on the gas-permeable hollow fiber membranes. Hence, a H-2-MBfR receiving approximately 20 mg N/l nitrate and 0.5 mg/l TC was operated under different H-2 pressures, hydraulic retention times (HRTs), and influent TC concentrations in order to provide various nitrate and TC loadings. The results showed that H-2-MBfR accomplished successfully the degradation of TC, and it reached TC removal of 80-95 % at 10 h of HRT and 6 psi (0.41 atm) of H-2 gas pressure. TC degradation took placed at increased HRT and H-2 pressures while nitrate was the preferred electron acceptor for most of the electrons generated from H-2 oxidation used for denitrification. The transformation products of TC were found at part per billion levels through all the experiments, and the concentrations decreased with the increasing HRT regardless of H-2 pressure. Analyses from clone library showed that the microbial diversity at the optimal conditions was higher than that at the other periods. The dominant species were revealed to be Betaproteobacteria, Acidovorax caeni, and Alicycliphilus denitrificans.

This study investigated organic matter (OM) and nutrient removal efficiency of mixed algal species from slaughterhouse wastewater (SWW) by using photo-bioreactor. For this purpose, different dilution multiples of 10, 4, and 2 were applied to the SWW, and pure wastewater was finally used for algal cultivation. OM and nutrient removal performance in an algal photo-bioreactor were severely affected by the dilution ratio. After 7 days of cultivation, the highest removal percentages of total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) were 89.6, 70.2, and 96.2 %, respectively. Furthermore, the changes in eukaryotic algae and cyanobacterial species in the algal photo-bioreactors were investigated using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) techniques. The results indicated that cyanobacterial species were more efficient than eukaryotic species in removing nutrients from the SWW. This study suggests that mixed algal photo-bioreactors could be used efficiently in the treatment of SWW.

In this study, electricity production from old age landfill leachate was investigated using dual chambered microbial fuel cell with Ti-TiO2 electrodes. The effect of organic loading rate on microbial fuel cell performance was examined by changing the hydraulic retention time and leachate chemical oxygen demand (COD) concentration. Microbial diversity at different conditions was studied using PCR-DGGE profiling of 16 sRNA fragments of microorganisms in the liquid media of the anode chamber and of the biofilm on the anode electrode. Both COD removal and current density were positively affected with increasing organic loading rate. The highest microbial fuel cell performance was achieved at hydraulic retention time of 0.5 day and organic loading rate of 10 g COD/L. day. The performance of the microbial fuel cell reactor decreased when hydraulic retention time was reduced to 0.25 day. The investigation of the microbial dynamics indicated that abundance of bacterial species was considerably dependent on the operational conditions. The microbial fuel cell reactor was mainly dominated by Geobacter, Shewanella, and Clostridium species, and some bacteria were easily washed out at lower hydraulic retention times.

Tetracycline antibiotics have been increasingly used in medical applications and have been found in wastewater treatment plants as a result of human and industrial activities. This study investigates the combined effects of tetracycline antibiotics on the performance of an algal photo-bioreactor operated under different antibiotic concentrations in the ranges of 0.25 to 30 mg/L and considers the inhibition of algal growth, carbon and nutrient removal rates, and eukaryotic and cyanobacterial algal community changes. The results indicated that increases in the concentration of tetracycline mixtures have adverse effects on the algal community and the performance of a photo-bioreactor, and the eukaryotic algae species were more sensitive to tetracycline antibiotics than were the cyanobacterial species. Cultivation tests showed that approximately 94 % growth inhibition of mixed algae occurred at 30 mg/L.

In the recent years, there has been considerable debate about the potential impacts of antibiotics present in various environments on the public health and ecology. Oxytetracycline (OTC) is one of tetracycline antibiotic group used for growth and treatment of animals and humans. In this study, OTC and nitrate (NO3-N) were simultaneously reduced using a hydrogen-based membrane biofilm reactor (H-2-MBfR). The system successfully accomplished OTC and nitrate removals. The fluxes of OTC and NO3-N were 8.96 mg OTC/m(2) day and 1100 mg N/m(2) day, respectively. On the other hand, the fluxes of H-2 utilized for OTC and NO3-N reductions were calculated as maximum values of 1.71 and 395 mg H-2/m(2) day, respectively. The concentrations of transformation products of OTC formed at ppb levels. The dominant species in all the experimental periods with OTC biodegradation referred to Naxibacter sp., Uncultured Beta proteobacterium, Janthinobacterium sp. and Alicycliphilus denitrificans in autotrophic biofilm community degrading OTC.

We evaluated a new electrode material for its capacity to generate electricity by using a cottonseed effluent in two microbial fuel cells (MFCs). Tin-coated copper (Sn-coating Cu) mesh and platinum-coated titanium were used as anode and cathode electrode materials, respectively. For a startup period that allowed slow-growing electro-active bacteria to form biofilms on the anode electrode, inoculums were supplied from anaerobic digester sludge (ADS) and estuary sediment (ES). The ADS-inoculated MFC successfully achieved maximum power density of 160 mW/m2, whereas ES-inoculated MFC had a maximum power density of 59 mW/m2. Maximum columbic efficiencies for ADS and ES were 12.8% and 5.6% and the corresponding COD removal efficiencies were 66.6% and 53.6%, respectively. A PCR-DGGE analysis showed that the anode surface in ADS-inoculated MFC has more groups of bacteria than that in ES-inoculated MFC. The kinetic performances of MFCs evaluated by using the Nernst–Monod equation showed that maximum current density (Jmax) increased to around 1.62 A/m2 in the ADS-inoculated MFC and 1.06 A/m2 in the ES-inoculated MFC. © 2015 American Institute of Chemical Engineers Environ Prog, 2015

This study focuses on two main aspects: developing a novel cost-effective electrode material and power production from domestic wastewater using three different mediators. Methylene blue (MB), neutral red (NR) and 2-hydroxy-1,4-naphthoquinone (HNQ) were selected as electrode mediators with different concentrations. A tin-coated copper mesh electrode was tested as anode electrode. Maximum power density of the microbial fuel cell (MFC) with 300 μM MB was 636 mW/m2. Optimal mediator concentrations with respect to the achieved maximum power output for MB, NR and HNQ were 300 μM, 200 μM and 50 μM, respectively. The results demonstrate that tin-coated copper mesh showed a higher biocompatibility and electrical conductivity.

Phenol can be oxidized to the end products when oxygen is used as an electron acceptor. This study evaluated phenol oxidation in an oxygen-based membrane biofilm reactor (MBfR). The system achieved highest oxidation of both phenol and glucose when the phenol loading and glucose loading was ∼4.7 and ∼55 g m−2 day−1, respectively. These conditions were sufficient to prove an O2 flux of at least 46 g O2 m−2 day−1. In the case of feeding solely with phenol, the MBfR accomplished the highest phenol oxidation (∼100%) when the phenol loading was about 5.6 ± 0.9 g m−2 day−1 and the O2 flux was higher than 13.4 ± 2.2 g O2 m−2 day−1. However, higher phenol loading could be compensated by a higher O2 pressure, and the best performance occurred when the phenol loading was 5.6 g m−2 day−1, the O2 pressure was ∼0.54 atm, and hydraulic retention time was 2.5 h. Membrane fouling caused a reduced O2 flux, which led to low phenol-oxidation efficiency. However, the bacterial population present in MBfR was analyzed by PCR-denaturing gradient gel electrophoresis and a low biodiversity was found.

Leachate treatment using a membrane bioreactor is an effective method. This study presents a configuration including an anaerobic bioreactor and a membrane module, called submerged anaerobic membrane bioreactor (SAnMBR), for treating influent with leachate/acetate rations (L/A), that were kept to be 10, 25, 50, 75, and 100% at a constant SRT (100 days). COD removal decreased from 85 to 75% when the L/A ratio increased from 10 to 100. To prevent membrane fouling, a SAnMBR was operated in the case of circulation of mixed liquor under continuous and intermittent suction. The average fluxes were 2.60 and 0.40 L/m2 h at the periods of intermittent and continuous suction, respectively. The methane production varied between 0.25 and 0.32 L CH4/g CODremoved.

This paper summarizes the comparison of a new tin-coated copper (t-coating Cu) mesh electrode with a graphite plate electrode for potential power generation and biocompat- ibility in a microbial fuel cell (MFC). The study, which used domestic wastewater, demon- strated that t-coating Cu mesh electrode produced a power density (271 mW/m 2 ) approxi- mately three times higher than that produced by a graphite electrode (87 mW/m 2 ). Scanning electron microscopy (SEM) results revealed that bacterial morphology on the two electrodes significantly varied. The t-coating Cu mesh electrode surface had higher bacterial diversity because the open three-dimensional macro-mesh structure allowed an excellent electro-biofilm attachment. Kinetic performances evaluated using the Nernst-Monod equation demonstrated that the t-coating Cu mesh electrode had both higher power density and good biocompatibility in a large surface area, high chemical stability, and favorable metallic conductivity.

Chlorinated ethenes in drinking water could be reductively dechlorinated to non-toxic ethene by using a hydrogen based membrane biofilm reactor (H-2-MBfR) under denitrifying conditions as it provides an appropriate environment for dechlorinating bacteria in biofilm communities. This study evaluates the reductive dechlorination of perchloroethene (PCE) to non-toxic ethene (ETH) and comparative community analysis of the biofilm grown on the gas permeable membrane fibers. For these purposes, three H-2-MBfRs receiving three different chlorinated ethenes (PCE, TCE and DCE) were operated under different hydraulic retention times (HRTs) and H-2 pressures. Among these reactors, the H-2-MBfR fed with PCE (H-2-MBfR 1) accomplished a complete dechlorination, whereas cis-DCE accumulated in the TCE receiving H-2-MBfR 2 and no dechlorination was detected in the DCE receiving H-2-MBfR 3. The results showed that 95% of PCE dechlorinated to ETH together with over 99.8% dechlorination efficiency. Nitrate was the preferred electron acceptor as the most of electrons generated from H-2 oxidation used for denitrification and dechlorination started under nitrate deficient conditions at increased H-2 pressures. PCR-DGGE analysis showed that Dehalococcoides were present in autotrophic biofilm community dechlorinating PCE to ethene, and RDase genes analysis revealed that pceA, tceA, bvcA and vcrA, responsible for complete dechlorination step, were available in Dehalococcoides strains. (C) 2014 Elsevier Ltd. All rights reserved.

Electrode materials play a key role in enhancing the electricity generation in the microbial fuel cell (MFC). In this study, a new material (Ti-TiO(2)) was used as an anode electrode and compared with a graphite electrode for electricity generation. Current densities were 476.6 and 31 mA/m(2) for Ti-TiO(2) and graphite electrodes, respectively. The PCR-DGGE analysis of enriched microbial communities from estuary revealed that MFC reactors were dominated by Shewanella haliotis, Enterococcus sp., and Enterobacter sp. Bioelectrochemical kinetic works in the MFC with Ti-TiO(2) electrode revealed that the parameters by non-linear curve fitting with the confidence bounds of 95% gave good fit with the kinetic constants of η (difference between the anode potential and anode potential giving one-half of the maximum current density) = 0.35 V, K (s) (Half-saturation constant) = 2.93 mM and J (max) = 0.39 A/m(2) for T = 298 K and F = 96.485 C/mol-e(-). From the results observed, it is clear that Ti-TiO(2) electrode is a promising candidate for electricity generation in MFC.

In this study, performance of MFC using three different mediators was investigated in terms of power density and internal resistance. Methylene blue (MB), neutral red (NR) and 2-hydroxy-1,4-naphthoquinone (HNQ)mediators were used to increase power generation in MFC with the mediator concentrations of 50, 100, 200, 300 and 400 µM. The maximum power densities were recorded as 36, 31 and 18.7 mW/m2withthe mediators of MB, NR and HNQ corresponding optimal mediator concentrations of 300, 200 and 50 µM, respectively. Further, it was observed that internal resistance changed with mediator concentration.