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Microbial fuel cell (MFC) is used to remove organic pollutants while generating electricity. Biocathode plays as an efficient electrocatalyst for accelerating the Oxidation Reduction Reaction (ORR) of oxygen in MFC. This study integrated biocathode into a single-chamber microbial fuel cell (BSCMFC) to produce electricity from an organic substrate using aerobic activated sludge to gain more insights into anodic and cathodic biofilms. The maximum power density, current density, chemical oxygen demand (COD) removal, and coulombic efficiency were 0.593 W m−3, 2.6 A m−3, 83 ± 8.4%, and 22 ± 2.5%, respectively. Extracellular polymeric substances (EPS) produced by biofilm from the biocathode were higher than the bioanode. Infrared spectroscopy and Scanning Electron Microscope (SEM) examined confirmed the presence of biofilm by the adhesion on electrodes. The dominant phyla in bioanode were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, while the dominant phylum in the biocathode was Proteobacteria. Therefore, this study demonstrates the applicable use of BSCMFC for bioelectricity generation and pollution control.

Microbial electrochemical cells (MXCs) have been developed as promising devices mainly for energy generation and wastewater treatment. Among the well-defined electroactive bacteria, Pseudomonas aeruginosa has been demonstrated for its electroactivity through mediated electron transfer in MXCs. In addition to phenazine pigments that mediate external electron transfer (EET), biofilm formation and rhamnolipid production are considered important factors affecting electricity generation by P. aeruginosa in MXCs. In the present study, a local electroactive strain of P. aeruginosa was isolated. Bacterial identification was done by Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and 16S rDNA as P. aeruginosa FA17. Cyclic voltammetric studies showed the appearance of oxidation peaks which contributes to pyocyanin. Plackett-Burman designs were employed to optimize the composition of artificial wastewater (AWW) media for current generation (represented the mediated electron transfer), biofilm formation and rhamnolipid production by FA17. Ammonium chloride was the significant variable affecting electron transfer of FA17 for current generation in three-electrode set-up by using cyclic voltammetry analyses. While phosphate, Sodium dodecyl sulfate (SDS) and chlorides were the major factors influencing biofilm formation by FA17, phosphate, inoculum size, MgSO4.7H2O, pH, and SDS were the significant variables for rhamnolipid production. This study provides knowledge about the electrochemical behavior of mediated electron transfer catalyzed by P. aeruginosa FA17, biofilm formation, and rhamnolipid production in response to medium composition, which leads to the possibility for the future development of power produced by MXCs using the electroactive FA17.

Background The development of powerful and flexible management addresses is due to the improvement of deeply reliable gadgets and the advancement of the concept of cellular. The cellular principle was a major way of solving the wavelength crowding problem and the user capacity. It offered high capacity without major technological changes with limited allocation in spectrum. Wireless communication is an innovation in media transmission that allows remote transmission in all types of terrain between convenient gadgets. For estimating a transmitter 's radio coverage area, propagation models that anticipate the mean signal strength for an arbitrary transmitter–receiver separation distance are crucial as they are called large-scale propagation models so even though they define the average signal strength over long periods of time and large distances from the transmitter. Results Developed propagation models are presented according to the measured path loss values in exemplary urban and suburban areas at the operating frequency of 3.5 ghz by using the regression analysis. The measurements are implemented by using a spectrum analyzer FSH6 to get the channel response as shown in the stated tables and graphs. Based on the obtained results, it was observed that the path loss could be calculated as a function of distance and during the practical measurements 32 m was precise as a presumption for the break point distance. The values of path loss exponent (n) are defined and calculated for both of urban and suburban regions. Measurements results are analyzed and compared in order to study their influence for every specific environment. It was noticed that any radio signal will suffer attenuation when it travels from the transmitter to the receiver as a variety of various phenomena give rise to this radio path loss. Conclusions The interaction between both the electromagnetic radiation and the environment tends to decrease the quality of the signal being sent from the transmitter to the destination which causes the loss of the path. Propagation models are the basis for channel estimation, as they attempt to identify how a radio transmission changes from the transmitter to the receiver throughout its path. The gained results from this research will be supportive for the arrangement of network planners and researchers as proof and directory materials before future location establishment.

Microbial fuel cells (MFCs) represent a new approach that can simultaneously enhance the treatment of waste streams and generate electricity. Although MFCs represent a promising technology for renewable energy production, they have not been successfully scaled-up mainly due to the relatively-low electricity generation and high cost associated with MFCs operation. Here, we investigated whether graphitic mesoporous carbon (GMC) decoration of carbon felt would improve the conductivity and biocompatibility of carbon felt anodes, leading to higher biomass attachment and electricity generation in MFCs fed with an organic substrate. To test this hypothesis, we applied 3 different GMC loading (i.e., 2, 5, and 10 mg/cm2 of anode surface area) in MFCs compared to control MFCs (with pristine carbon felt electrodes). We observed that the internal resistances of modified anodes with GMC were 1.2–2.3-order of magnitude less than pristine carbon felt anode, leading to maximum power densities of 70.3, 33.3, and 9.8 mW/m2 for 10, 5, and 2 mg/cm2-doped anode, respectively compared to only 3.8 mW/m2 for the untreated carbon felt. High-throughput sequencing revealed that increasing the GMC loading rate was associated with enriching more robust anode-respiring bacteria (ARB) biofilm community. These results demonstrate that 3-D GMC-doped carbon felt anodes could be a potential alternative to other expensive metal-based electrodes for achieving high electric current densities in MFCs fed with organic substrates, such as wastewater. Most importantly, high electron transfer capability, strong chemical stability, low cost, and excellent mechanical strength of 3-D GMC-doped carbon felt open up new opportunities for scaling-up of MFCs using cheap and high-performance anodes.

Background Microalgae cells can be identified as a potential source for new and renewable energy. The economic investigation for biodiesel and bio-active compound production from the microalgae community (Bloom), which are collected from the high rate algal pond (HRAP) constructed to treat municipal wastewater at Zenin wastewater treatment plant, Giza, was the main target of study. Results The microscopical examination showed that Scenedesmus obliquus is the dominant species. The total carotenoids were extracted using jojoba oil and determined by high-performance liquid chromatography (HPLC) to reach 81.44 μg/g. The biodiesel production through acid transesterification reaction recorded 70.6% of fatty acid methyl ester content with high cetane number (44) and low acid value. Such results prove that the obtained biodiesel has better ignition quality. The total phenolic and flavonoid compounds have been derived from the remaining biomass to give 5.36 ± 0.03 and 1.50 ± 0.19 mg/g respectively. Finally, total proteins and carbohydrates content in algal cells were recorded 54.3 and 1.5 mg/g successively Conclusion The preliminary economic evaluation showed that the production of biodiesel and carotenoids from the microalgae growing in municipal wastewater can be considered, as a techno-economic feasible process.

The economic feasibility of growing Nannochloropsis sp. at the commercial scale was evaluated for the production of biodiesel and co-products. A local isolate of Nannochoropsis was grown in (6) 200-L raceway ponds at Alexandria University wherein cultures reached maximum cell concentrations ~ 4–6 × 107 cells/mL (0.63–0.88 g/L dry weight) and a peak biomass productivity of 0.09 g/L/day during mid- to late-log growth. Areal productivity was estimated at 17.65 g/m2/day when ponds were operated on a semi-batch schedule, harvesting 50% every 2 days and recycling 60% of the media. Areal productivity was estimated around 10.3 g/m2/day for batch schedules. Late-log cultures harvested from all ponds yielded 10 kg of wet algal paste, which was reduced to 1.05 kg of dried algal powder. The biomass was composed of valuable co-products approx. 14.0% carbohydrate, 37.3% protein, 0.01% chlorophyll-a, and 0.02% carotenoids (w/w). Total lipid made up 38% of the biomass (w/w); 34% of the biomass was determined to be neutral lipid which are transesterified to biodiesel and 4% are polar lipid. Fatty acids from glycerolipids were quantified by gas chromatography-flame-ionization detector (GC-FID) as fatty acid methyl esters (FAMEs) revealing carbon-chain lengths from C6 to C22. A preliminary economic evaluation was conducted to determine the feasibility of constructing commercial-scale algae biodiesel production facilities in Egypt. The return on investment (ROI) of the current economic feasibility study for biofuel production alone was 22% after considering the market prices of the biodiesel, cake, and glycerol by-products. Based on this assessment, additional high-value products are needed to improve the ROI. Noting that the valuable co-products are considered as added cost in the biomass left after biodiesel production.

In the present work, Water Hyacinth Biochar (WHB) was produced by pyrolysis at 900 °C and then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX-SEM, Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area and particle size analyses. The results indicate that WHB has Oxygen Reduction Reaction (ORR) catalytic activity, with an average of 2.58 electrons per oxygen molecule transferred from WHB for ORR. The ORR catalytic activity of WHB is attributed to its physical and chemical surface properties. The maximum power density produced from an air cathode single chamber microbial fuel cell (ACSC-MFC) with WHB as the ORR catalyst versus the Pt/C catalyst were 24.7 and 12.3 mWm−2, respectively. This study demonstrates that Water Hyacinth Biochar can be used as an inexpensive catalyst for the ORR in microbial fuel cells.

La 0.8 Sr0.2MnO3 (LSM) polycrystalline powder was synthesized using hydrothermal method at 900 °C. High Resolution Transmission Electron Microscope (HR-TEM) showed that the particles were uniform with average particle size of 657 nm. X-ray Diffraction (XRD) and lattice fringes indicated rhombohedral structure of LSM particles. Thin LSM films were successfully grown on cleaned Si (100) substrate by pulsed laser deposition (PLD). Annealing of LSM films in air affected structure, morphology and electrical properties that films where crystallization of the LSM films was started at 600 °C and enhanced by further annealing as indicated by XRD. Field Emission Scanning Electron Microscope (FESEM) revealed that the grain size increases by increasing annealing temperature and at temperature of 1000 °C cracks were seen. Average roughness and root mean square roughness decreased with further annealing (up to 800 °C) then increased at 1000 °C that were verified by atomic force microscope (AFM). Moreover, Raman scattering was enhanced and all major bands were revealed at 800 °C. Resistivity of LSM films decreases with increasing temperature (from 25 °C to 200 °C) and all films underwent a semiconductor behavior in the most of applied temperatures. The lowest resistivity of LSM films was reached at annealing temperature of 800 °C with low activation energy value (Ea) of about 0.1 eV.

Carbon supported platinum nanoparticles are commonly used as anode catalysts in low temperature fuel cells. Platinum exhibits an enhanced activity towards hydrogen oxidation reaction; however, its performance during low molecular weight alcohols oxidation is poor. Accordingly, this work presents a trial to improve the electrocatalytic performance of platinum-based electrocatalysts by developing core-shell structured M@Pt [M = Zn, Mn or Sn] nanoparticles supported on activated Vulcan XC-72R carbon black [M@Pt/AC]. They were fabricated using ethylene glycol as a reducing agent with the aid of microwave irradiation. The electrocatalytic activity of different M@Pt/AC electrocatalysts for oxidizing methanol molecules in 0.5 M H2SO4 solution was investigated using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. These prepared nanomaterials displayed enhanced electrocatalytic behavior towards methanol oxidation reaction. The alcohol oxidation current density was arranged in an ascending order as: Zn@Pt/AC

In this research we present the measured path loss values in typical urban and suburban areas at the operating frequency of 3.5 GHz. The measurements are carried out using the spectrum analyzer FSH6 in order to record the channel response. The values of path loss exponent n are calculated for urban and suburban environments. We also compare and analyze the path loss predictions with the measured data. The results of this research confirm that in urban areas the path loss estimation is influenced according to the greater distances. At the beginning of the measurements in urban environment the losses are equal 23 dB after 18 m from the measurement survey. The analysis of measurements centers on anticipating the normal signal quality at the collector set at the given remove from the transmitter as well as the changeability of the signal quality in the specific environment. The acquired from this work results are salutary for planning and installation of any base station with similar to the thoughtful locations environments in order to supply rules for cell arranging of remote communication frameworks as path loss could be a key in calculations within the plan of any radio communications framework system.

Mixed transition metal (Ni & Cu) oxides supported on graphene (NiO-CuO/G) electrocatalyst was fabricated and tested as an efficient and cost-effective cathode for oxygen reduction reaction (ORR) in microbial fuel cells (MFCs). The electrocatalytic activity and selectivity of the NiO-CuO/G for ORR were examined using linear sweep voltammetry measurements (LSV) on a rotating disc electrode (RDE) in pH-neutral electrolyte. In comparison with a benchmark platinum cathode, the NiO-CuO/G showed high selectivity towards the ORR. The analysis of Koutecky-Levich relationship suggests that the electrocatalyst follows the four-electron ORR pathway. NiO-CuO/G cathode in an air-cathode MFC exhibited a slightly lower power density 21.25 mWm− 2 compared to 50.4 mW m− 2 for Pt/C. Both scanning and transmission electron microscope analyses of anodic biofilm showed that a thick biofilm was successfully developed with a rod-like shape. Biochemical characterization of the communities showed that four genera named Escherichia coli (E-coli), Shewanella putrefaciens, Bacillus cereus and Bacillus Thuringiensis/mycoides, which belonging to GammaProteobacteria and Firmicutesphylathatwerethe most abundant bacteria in the anodic biofilm. Our results revealed that NiO-CuO/G cathode demonstrates an enhanced electrocatalytic activity toward ORR in a pH-neutral solution; thus, the newly developed mixed transition metal oxides electrocatalyst can replace other expensive Pt-based catalysts for MFC application.

The effect of adding a transition metal (M) to the core structure of M@Pt/C electrocatalyst on its electrocatalytic activity towards ethanol oxidation reaction in alkaline medium was studied. Copper or nickel or cobalt was reduced on Vulcan XC-72R carbon black surface using sodium borohydride followed by introducing platinum ions in the shell structure. The crystalline nature and the electrocatalyst morphology were investigated using XRD and TEM analysis techniques. Cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry were applied to evaluate the electrocatalytic characteristics of prepared nanocatalysts during alcohol electro-oxidation. The electrocatalytic activity showed an ascending behavior as Cu@Pt/C

Core-shell nanoparticles of Ni@Pt/C electrocatalysts have been prepared in different Pt:Ni atomic ratios ranging from 1:0.25 to 1:3 through a two-step strategy using ethylene glycol as a reducing agent. Their electrocatalytic activity for ethanol oxidation was investigated in alkaline medium. X-ray diffraction and transmission electron microscopy were employed to evaluate crystal structure and surface morphology. Highly dispersed Pt nanoparticles were distributed in all prepared Ni@Pt/C electrocatalysts. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy have been applied to examine the electrochemical performance of Ni@Pt/C electrocatalysts. Increasing nickel content was found to enhance the resultant electrocatalytic activity towards ethanol oxidation. Ni@Pt/C containing Pt:Ni atomic ratio of 1:3 exhibited the highest oxidation current density and stability when contrasted to Pt/C and other Ni@Pt/C electrocatalysts.

This study investigates the performance of acetate feed membrane less single chamber microbial fuel cell and physical characterization of the bio film present on the anode surface using Scanning Electron Microscope (SEM) and 16S rRNA analyzer. The performance has been investigated using Teflon treated carbon paper with 0.3 mg/cm 2 Pt/C loaded as a cathode and carbon paper as an anode. The maximum open circuit potential is noticed as 791 mV, the system successfully revealed a maximum power density of 86.1 mW m −2 at stable current density of 354 mA m −2 with high coulombic efficiency of 65% at maximum degradation rate of 96%. SEM showed the dense adherence of microorganisms on the anode. 16S rRNA sequencing results indicates phylogenetic mixture in the communities of anodic biofilm and there is no single dominant bacterial species. The dominant phyla are Firmicutes , Gamma Proteobacteria , Alpha Proteobacteria , Actinobacteria , with ten dominant microbial strains: Bacillus firmus , Shewanella profunda , Bacillus isronensis , Brevundimonas bullata , Pseudomonas putida , Planococcus citreus , Micrococcus endophyticus , Acinetobacter tandoii , Bacillus safensis and Shewanella xiamenensis .

Core–shell nanoparticles of Cu@Pt/C electrocatalysts were synthesized using various Pt:Cu atomic ratios with NaBH4 as a reducing agent. The crystal structure and surface morphology were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The incorporation of copper in Cu@Pt/C electrocatalysts was found to shift all Pt diffraction planes in the negative direction with expanding the crystal lattice dimensions. The electrocatalytic activity of various Cu@Pt/C electrocatalysts was investigated using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Cu@Pt/C electrocatalysts containing Pt:Cu atomic ratios of 1:0.5 and 1:2 showed an enhanced electrochemical performance for ethanol oxidation when related to Pt/C.

Biodiesel is one of those renewable fuel sources developed to fuel transportation sector to replace conventional petroleum based fuels. In the present work the key concentration is directed towards highlighting engineering and biological issues to resolve the production of biofuels from microalgae to become an economic reality. This study discusses the unit processes required for algal biofuels production in municipal wastewater (i.e. growing the algae, harvesting, dewatering, extraction and conversion to biofuel) and their scalability. The economic estimation in this article is classified as a ‘‘study estimate’’ which had a range of expected accuracy from +30% to −20%. The comparison between Microcystis aeruginosa grown in lab scale and microalgae grown in the oxidation pond system demonstrated that a mixed culture of algae species could successfully be grown on wastewater nutrients and potentially scaled to commercial production. Spirulina maxima was the most dominant species of microalgae in samples collected from Matrouh wastewater treatment plant, and responsible for the over growth detected in the maturation bond. Extracted oil from both Spirulina maxima and Microcystis aeruginosa was transesterified to evaluate the fatty acid methyl ester produced and to identify the purity of the biodiesel. Complete process simulation was carried out using a process simulation software. Assuming that the rate of biodiesel production needed was 10,000 t/year, all process units required have been sized. Total capital investment, total manufacturing cost and return on investment (ROI) were all estimated. The ROI of Spirulina maxima case equaled to 86.92%, while in case of Microcystis aeruginosa was −56.5%. So, the biofuel production from Spirulina maxima grown in wastewater treatment plants is being economically feasible.

Pt-CeO2 /C, Pt-TiO2 /C, and Pt-ZrO2 /C electrocatalysts were prepared by using a modified microwave-assisted polyol process. Physical characterization was performed by using XRD, TEM, and EDX analyses. The incorporation of different metal oxides increased the dispersion degree of Pt nanoparticles and reduced their diameter to 2.50 and 2.33 nm when TiO2 and ZrO2 were introduced to Pt/C, respectively. The electrocatalytic activity of various electrocatalysts was examined towards methanol oxidation in H2 SO4 solution by using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Among the studied composites, Pt-ZrO2 /C was selected to be a candidate electrocatalyst for better electrochemical performance in direct methanol fuel cells.

Different carbon supports are considered to prepare Pt–ZrO 2 /XC-72R carbon black, Pt–ZrO 2 /SWCNTs and Pt–ZrO 2 /MWCNTs electrocatalysts by a solid–state reaction under intermittent microwave heating method using ethylene glycol and NaBH 4 as mixed reducing agents. The prepared electrocatalysts are physically characterized using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). Pt particle size decreases in the order: Pt–ZrO 2 /C > Pt–ZrO 2 /MWCNTs > Pt–ZrO 2 /SWCNTs. Cyclic voltammetry, chronoamperometry, chronopotentiometry and electrochemical impedance spectroscopy are applied to investigate the electrochemical performance of the three electrocatalysts for methanol oxidation in H 2 SO 4 solution. CNTs supported electrocatalysts achieve increased methanol oxidation current density and improved stability behaviour during long-time operation when compared to the one containing carbon black. Pt–ZrO 2 /CNTs electrocatalyst also displays lower resistance and higher electrolyte diffusion rate to infer a faster charge transfer process and better electrode accessibility for methanol oxidation. Therefore, carbon nanotubes are suggested as ideal anode electrocatalyst supporting material for the practical application of direct methanol fuel cells.

The modification of Pt/C by incorporating metal oxides for electrocatalytic oxidation of methanol has gained major attention because of the efficiency loss during the course of long-time operation. This work describes the preparation of Pt–MnO2/C electrocatalysts through a chemical route using ethylene glycol or a mixture of ethylene glycol and sodium borohydride as a reducing agent. The crystallite structure and particle size of synthesized electrocatalysts are determined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The addition of MnO2 improves the dispersion of Pt nanoparticles. The electrocatalytic activity of Pt–MnO2/C towards methanol oxidation in H2SO4 solution is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The onset potential value of methanol oxidation peak is negatively shifted by 169 mV when MnO2 is introduced to Pt/C. Moreover, the charge transfer resistance value at Pt–MnO2/C is about 10 times as low as that at Pt/C. Chronoamperometry and chronopotentiometry show that CO tolerance is greatly improved at Pt–MnO2/C. The increased electrocatalytic activity and enhanced ability to clean platinum surface elect manganese oxide as a suitable promoter for the anode performance in direct methanol fuel cells (DMFCs).

The corrosion resistance of electroless Ni–P coating on pure Al, Al 6061, Al 3004 and Al 1050 is examined in an environment simulated to PEM fuel cell. Potentiodynamic polarization techniques, Interfacial contact resistance, surface morphology, chemical composition of coated substrates and EIS measurements have been investigated. Modified Al 1050 showed reduction in its corrosion current density by 44.69 times. It also showed the best stability of all modified Al substrates. The formed Ni–P layer on Al 1050 is thicker by about 3 times, relative to that on Al 6061 and has higher E a value of 135.68 kJ mol −1 supporting its lower corrosion rate.

Graphical abstract Jet fuel production using thermal cracking of biodiesel., Distillate of upgraded palm biodiesel was blended in different volume percentages (5, 10, 15, and 20%) with jet A-1. The mixture can be used as a replacement for petroleum Jet fuel. Physical properties of blends were measured and compared with those of jet A-1. Empirical equations were developed to predict the properties of blended fuel, including density, kinematic viscosity, freezing point, H/C ratio, and acid value. The statistical analysis indicated that the proposed equations predictions agree well with the experimental data. The predicted model shows an (R2) between 0.99–0.98, indicating good fitting between the experimental data and proposed model. The distillate of upgraded palm biodiesel was miscible with the kerosene jet A-1 in all volume fractions under study 5–20%. The economic analysis shows that the production cost per unit of the produced bio jet fuel was much higher than the selling price of the petroleum jet fuel. This price difference is due to the raw materials cost; as the palm oil used is nearly three times that of crude oil. The economic evaluation study reveals that the operating cost of prepared bio jet equals to 2360 $/ton, which is a promising result.

Pt-MOx/C (M = Ti, Ce or Zr) electrocatalysts was prepared for the purpose of developing a cheap and efficient electrocatalysts for oxygen reduction reaction (ORR) using a mixture of ethylene glycol and sodium borohydride (EG + NaBH4) as a reducing agent. Pt/C was studied for estimation of metal oxides effect.Pt-CeO2/C-1 was prepared through single reducing agent ethylene glycol for studying the effect of changing the reducing agent on the activity of electrocatalysts toward ORR and for studying ORR kinetics. The electrocatalytic activity of the prepared electrocatalysts towards (ORR) was evaluated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) on a rotating disc electrode (RDE). Pt-ZrO2 /C shows the best activity towards ORR among the studied electrocatalysts; the oxygen reduction current density for it is about 5 times; (5.84 mAcm-2) as that of Pt/C (1.26 mAcm-2). Pt-CeO2/C showed better ORR activity (2.24 mAcm-2) than Pt-CeO2/C-1(1.58 mAcm-2) indicating the great effect of changing the reducing agent not only on the electrocatalyst behavior towards ORR but also its particle size and the metal content of the resultant electrocatalysts. Oxygen reduction mechanism for Pt-CeO2/C and Pt-CeO2/C-1 was evaluated using through Koutecky-Levich, they showed first-order kinetics with ORR not controlled solely by diffusion. XRD, EDX and TEM analyses were used to characterize the prepared electrocatalyst.

Noble metal oxides (IrO x , RuO x ) and valve metal oxides (SnO x and VO x ) have been investigated as promoters of Pt electrocatalyst for methanol oxidation in acidic environment. Pt modification was made using low oxide content (5 wt%) in order to evaluate the possibility of using such oxide promoter in a multifunctional catalyst. At this low level of oxide content, IrO x provided a larger promoting effect than RuO x . This occurred in the absence of specific alloying with Pt and also in the presence of lower catalyst dispersion. The electrocatalytic enhancement produced by the valve metal oxides was significantly lower than IrO x and RuO x . These results are interpreted in terms of the different water displacement mechanism for the various oxides. Such evidences seem to indicate that a multifunctional catalyst may represent a valid route to enhance methanol electro-oxidation.

Pd, Ni and Pd–Ni nanoparticles uniformly dispersed on Vulcan XC-72R carbon black are prepared by microwave-irradiation using NaBH 4 as a reducing agent. Pd/C, Ni/C and Pd–Ni/C electrocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). Pd–Ni alloy was formed with an average particle size of 3 nm. Kinetic parameters such as the electron transfer coefficient value ( α ) and electron transfer rate constant of Ni/C and Pd–Ni/C electrocatalysts in 0.5 M KOH solution were calculated. The prepared electrocatalysts were examined for methanol oxidation in alkaline medium. The long-term stability of electrocatalysts in (0.6 M MeOH + 0.5 M KOH) solution was studied using repeated cyclic voltammetry and chronoamperometry. Two methanol oxidation peaks were observed at Pd–Ni/C at 0 and +913 mV. Their current density values are higher than those at Pd/C and Ni/C electrocatalysts by 3.84 and 1.43 times, respectively. The catalytic rate constant at Ni/C and Pd–Ni/C was estimated using double-step chronoamperometry as 1.80 × 10 3 and 5.88 × 10 3 cm 3 mol −1 s −1 , respectively. Pd–Ni/C showed better stability performance when compared to Pd/C and Ni/C electrocatalysts.

Ni and Pd–Ni nanoparticles were chemically deposited on Vulcan XC-72R carbon black by impregnation method using NaBH4 as a reducing agent. The prepared electrocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The electrocatalytic activity of Ni/C and Pd–Ni/C electrocatalysts towards methanol oxidation in 0.5 M KOH solution was examined using cyclic voltammetry and chronoamperometry. Two methanol oxidation peaks were observed on the Pd–Ni/C at 0 and +860 mV. Their current density values are higher than those at Pd/C and Ni/C electrocatalysts by 1.92 and 1.68 times, respectively. The catalytic rate constant of methanol oxidation reaction at Ni/C and Pd–Ni/C electrocatalysts in (0.2 M MeOH + 0.5 M KOH) solution was estimated using double-step chronoamperometry as 5.64 × 103 and 6.25 × 103 cm3 mol−1 s−1, respectively. Pd–Ni/C is more stable than Pd/C and Ni/C electrocatalysts. Therefore, Pd–Ni/C is a suitable as a less expensive electrocatalyst for methanol oxidation in alkaline medium.

Aluminium alloy 6061 (AA6061) is coated with Ni–P and Ni–Mo–P using electroless and electroplating techniques. Coated substrates were characterized using scanning electron microscopy and energy dispersive X-ray analysis. Potentiodynamic polarization technique is applied to investigate the corrosion resistance characteristics of coated AA6061 in (0.5 M H 2 SO 4 + 2 ppm HF) solution. Coating AA6061 with Ni–P and Ni–Mo–P shifts its corrosion potential towards more positive values and lowers the corresponding current density values. The stability of prepared coatings under simulated cathode condition in PEM fuel cells is tested in air-saturated solution at +160 mV versus (mercury/mercury sulphate electrode (MMS)) for 5 h. After 40 min from starting the polarization test, Ni–P coating is found to be more stable than Ni–Mo–P. Ni–P and Ni–Mo–P coated AA6061 show a lowered ICR value at a compaction force of 140 N cm −2 by 2.22 and 1.88 times, respectively when compared to bare aluminium alloy.

In the present work the alkali in-situ transesterification of rapeseed with methanol for the production of biodiesel fuel was studied. Experiments were designed to determine how variations in molar ratio of methanol to oil in seeds, amount of alkali catalyst, time and temperature affected the yield. Good results (90%) conversion of seed lipid to fatty acid methyl ester was obtained at 0.02 N catalyst concentration, 720/1 methanol to rapeseed oil molar ratio, 1 h reaction time and 65 degrees C reaction temperature. The results were in agreement with the values measured by H-1 NMR spectroscopy. A mass balance and a preliminary feasibility study were investigated. A techno-economic analysis of the process for production of biodiesel from rapeseed with a capacity of 50,000 t/yr was presented to investigate the profitability indicators of the production capacity. The techno-economic indicators showed that total capital investment of $16,065,000, gross profit/year of $14,630,300, and percentage simple rate of return (%SRR) was 79.5% for a constant estimated price of $945/t while the specific biodiesel prices for SRR% of 10 and 50 were $722 and $850 respectively. (C) 2012 Elsevier Ltd. All rights reserved.

Nano PtCuO particles were deposited on Vulcan XC-72R carbon black using the impregnation and microwave irradiation methods. The prepared catalysts were characterized by XRD, TEM and EDX analyses. TEM images indicated that the microwave method provides homogeneously distributed catalyst particles in smaller size, compared to the one prepared by the impregnation method. The electrocatalytic activity of Pt‒CuO/C electrocatalysts was investigated to oxidize methanol in 0.5 M H2SO4 solution by applying cyclic voltammetry and chronoamperometry techniques. The oxidation current density of Pt‒CuO/C electrocatalyst, prepared by the microwave method, showed two folds increment with a potential shift in the negative direction by 69 and 36 mV at the first and second oxidation peaks, respectively, relative to those at the catalyst prepared by the impregnation method. The effect of varying methanol concentration on the resulting oxidation current density of Pt‒CuO/C electrocatalysts was studied. Some kinetic information about the reaction order with respect to methanol and Tafel slope values was calculated. Slower current density decay was observed in the chronoamperogram of Pt‒CuO/C electrocatalyst, prepared by the microwave method, reflecting a lower degree of surface poisoning.

Pure Al and some of its alloys [Al alloy 6061 (AA6061), Al alloy 3004 (AA3004) and Al alloy 1050 (AA1050)] were coated with Ni–Co–P using electroplating power supply technique. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were applied to study the surface morphology and chemical composition of coated aluminum substrates. Their performance against corrosion was examined using potentiodynamic polarization technique in (0.5 M H2SO4 + 2 ppm HF) solution. Corrosion potential values were shifted in the positive direction at all aluminum substrates after their coating with Ni–Co–P. Corrosion current density values at coated pure Al and AA1050 were decreased by ∼18.6 times, compared to those at bare substrates. The stability of coated aluminum alloys was investigated during long-time operation under cathodic environment in PEMFCs using potentiostatic polarization test at +160 mV (MMS) in air-saturated solution. Ni–Co–P/AA3004 substrate showed a high corrosion rate after short time, while coated AA6061 one slowly corroded. Interfacial contact resistance (ICR) values between metallic bipolar plates and gas diffusion layer were measured. Coating AA1050 with Ni–Co–P reduces its ICR value by 13 times. Accordingly, electroplated Ni–Co–P/AA1050 substrate can be chosen as an efficient bipolar plate material in PEMFCs.

This study is aimed to replace graphite bipolar plates in PEM fuel cells with surface modified aluminum alloy. To improve the surface characteristics of aluminum alloy 5251 (AA5251) substrate, Ni–P and Ni–Co–P coatings were deposited using electroless and electroplating deposition techniques [power supply and chronoamperometry]. Surface morphology and chemical composition of prepared coatings have been investigated using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The corrosion behaviour of Ni–P and Ni–Co–P coated AA5251 was studied in (0.5 M H2SO4 + 2 ppm HF) solution by potentiodynamic polarization technique. Lower corrosion current densities and more positive corrosion potentials were gained after coating AA5251 with Ni–P and Ni–Co–P deposits. Much better corrosion resistance was shown by coatings containing cobalt. Potentiostatic tests were carried out at +160 mV (MMS) in air-saturated solution to simulate cathode environment in PEM fuel cells. The current density of Ni–Co–P (1:1)/AA5251 was stabilized at a value lowered by 4 times relative to that at bare AA5251 substrate. Interfacial contact resistance values between coated substrates and carbon paper were measured. Ni–P and Ni–Co–P coatings prepared by electroless method showed ICR values, twice that at ones prepared by electroplating power supply technique.

Pt catalyst was supported on Vulcan XC-72R containing 5 wt.% NiO using NaBH 4 as a reducing agent. The prepared catalyst was heat-treated at 400 °C. XRD, TEM and EDX analyses were applied to characterize Pt–NiO/C electrocatalyst. The introduction of NiO reduces the particle size of Pt crystallites. The electrocatalytic activity of Pt–NiO/C electrocatalysts was examined towards methanol oxidation reaction in 0.5 M H 2 SO 4 solution using cyclic voltammetry and chronoamperometry techniques. A three fold increment in the oxidation current density was gained at Pt–NiO/C electrocatalyst compared to Pt/C one. The corresponding chronoamperograms showed high steady state current density values suggesting better stability of Pt–NiO/C electrocatalyst towards the carbonaceous poisoning species. The enhanced electrocatalytic performance and the long-term cycle durability of Pt–NiO/C electrocatalyst are attributed to the strong interaction between Pt and NiO and the formation of small Pt crystals.

Pt and Pt–Co supported on MWCNTs were synthesized by the impregnation method using NaBH 4 as the reducing agent. The effect of varying NaBH 4 concentration on particle size, morphology and chemical composition of Pt–Co/MWCNTs was studied. A homogeneous distribution of Pt–Co nanodeposits with particle size of 2–5 nm was attained in TEM images at Pt–Co/MWCNTs “×70” powder. EDX analysis confirmed the reduction of higher amount of Co in Pt–Co/MWCNTs “×40” electrocatalyst. The electrochemical activity of Pt/MWCNTs and Pt–Co/MWCNTs electrocatalysts was examined towards methanol oxidation reaction in 0.5 M H 2 SO 4 solution by employing the cyclic voltammetry and the chronoamperometry techniques. The lowest onset potential and the highest oxidation current density were gained at Pt–Co/MWCNTs “×70” electrocatalyst. Its good stability over the long-term performance study elects it as a promising candidate for the DMFCs applications.

This study focused on the use of spinel manganese–cobalt (Mn–Co) oxide, prepared by a solid state reaction, as a cathode catalyst to replace platinum in microbial fuel cells (MFCs) applications. Spinel Mn–Co oxides, with an Mn/Co atomic ratios of 0.5, 1, and 2, were prepared and examined in an air cathode MFCs which was fed with a molasses-laden synthetic wastewater and operated in batch mode. Among the three Mn–Co oxide cathodes and after 300 h of operation, the Mn–Co oxide catalyst with Mn/Co atomic ratio of 2 (MnCo-2) exhibited the highest power generation 113 mW/m2 at cell potential of 279 mV, which were lower than those for the Pt catalyst (148 mW/m2 and 325 mV, respectively). This study indicated that using spinel Mn–Co oxide to replace platinum as a cathodic catalyst enhances power generation, increases contaminant removal, and substantially reduces the cost of MFCs.

This work concerns preparation of acid-base polyelectrolyte membranes for fuel-cell applications from cellulosic backbones for the first time. Grafted cellophane-phosphoric acid-doped membranes for direct oxidation methanol fuel cells (DMFC) were prepared following three steps. The first two steps were conducted to have the basic polymers. The first step was introducing of epoxy groups to its chemical structure through grafting process with poly(glycidylmethacrylate) (PGMA). The second step was converting the introduced epoxy groups to imides groups followed by phosphoric acid (PO3H) doping as the last step. This step significantly contributes to induce ion exchange capacity (IEC) and ionic conductivity (IC). Chemical changes of the cellophane composition and morphology characters were followed using FTIR, TGA, and SEM analysis. Different factors affecting the membranes characters especially IEC, methanol permeability, and thermal stability were investigated and optimized to have the best preparation conditions. Compared to Nafion 117 membrane, cellophane-modified membranes show a better IEC, less methanol permeability, and better mechanical and thermal stability. IEC in the range of 1–2.3 meq/g compared to 0.9 meq/g per Nafion was obtained, and methanol permeability has been reduced by one-order magnitude. However, the maximum obtained IC for cellophane-PGMA-grafted membrane doped with phosphoric acid was found 2.33 × 10−3 (S cm−1) compared to 3.88 × 10−2 (S cm−1) for Nafion 117. The obtained results are very promising for conducting further investigations taking into consideration the very low price of cellophane compared to Nafion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Novel poly(glycidyl methacrylate)-grafted Nafion–phosphoric acid membranes for direct-oxidation methanol fuel cells were prepared with a potassium persulfate chemical initiation system for the first time. The introduced epoxy groups were converted to amine groups through a reaction with ethylenediamine, which consequently doped with phosphoric acid (APO3H) groups. The latter significantly contributed to enhancing the ionexchange capacity, mechanical properties, and thermal stability. Factors affecting the modification steps were studied. Changes in the chemical and morphological structure were verified through Fourier transform infrared spectroscopy, TGA, and scanning electron microscopy characterization. Various grafting percentages (GP%’s) up to 32.31% were obtained. As a result, the thickness of the grafted membranes increased. Furthermore, the methanol permeability of the modified membranes was reduced with increasing grafted polymer content compared with that of the Nafion membrane. An 83.64% reduction in the methanol permeability was obtained with a polymer grafted content of 18.27%. Finally, the efficiency factor for all of the modified Nafion membranes was enhanced compared with that of Nafion. A fourfold improvement was obtained with membranes with a GP% of 18.27% as a maximum value. Such promising results nominate the used technique as a one for the improvement of Nafion membrane efficiency. VC 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 120–133, 2011

The electrocatalytic oxidation of methanol was studied on Ni–P and Ni–Cu–P supported over commercial carbon electrodes in 0.1 M KOH solution. Cyclic voltammetry and chronoamperometry techniques were employed. Electroless deposition technique was adopted for the preparation of these catalysts. The effect of the electroless deposition parameters on the catalytic activity of the formed samples was examined. They involve the variation of the deposition time, pH and temperature. The scanning electron micrography showed a compact Ni–P surface with a smooth and low porous structure. A decreased amount of nickel and phosphorus was detected by EDX analysis in the formed catalyst after adding copper to the deposition solution. However, an improvement in the catalytic performance of Ni–Cu–P/C samples was noticed. This is attributed to the presence of copper hydroxide/nickel oxyhydroxide species. It suppresses the formation of γ-NiOOH phase and stabilizes β-NiOOH form. Linear dependence of the oxidation current density on the square root of the scan rate reveals the diffusion controlled behaviour.

Biomass to biofuels production technologies are promising to reduce CO2 emissions. Complementing the fuel-production technologies is improvement in their end use, wherein efforts are underway to maximize fuel cell efficiency. In the polymer electrolyte membrane (PEM) fuel cell research and development (R&D), the metallic bipolar plate concept looks promising, but issues such as cost, corrosion resistance, interfacial contact resistance (ICR), and reactant gases impurities still need to be resolved. Of these, bipolar plate material and impurities in oxygen or hydrogen extracted from biomass gasification can have considerable influence on fuel cell performance. In this paper, measurements of the ICR between the gas diffusion layer (GDL) and a number of bipolar plate materials were obtained and analyzed. The ICR data showed a significant effect on the electric power output of the fuel cell. Additionally, typical impurities in oxygen gas were found to have an adverse effect on throughput of the fuel cell due ...

A comparative study of an integrated hybrid membrane –based system with an earlier locally designed RO unit, such system comprises of Nanofiltration (NF), Reverse osmosis (RO) and Membrane Distillation (MD) subsystems. The comparison is essentially based on using the NF technique in pretreatment section, while the MD was contributed to concentrate the two brine streams from both NF and RO. The proposed system was economically evaluated and compared with the RO unit.

Corrosion resistant metal treated bipolar plates with higher rigidity and electrical conductivity than graphite were developed and tested for polymer electrolyte membrane (PEM) fuel cell applications. Four replicas of single cells were fabricated; two of graphite composites bipolar plates and the other two were coated aluminum. An E-TEK Series 14-W MEA with carbon cloth GDL, Nafion 112, 1.0 mg cm−2 platinum loading (anode and cathode) and 6.45 cm2 active electrode areas, was fitted to each cell and operated under identical conditions. The obtained data from the two graphite cells were averaged and plotted and the other two aluminum cells’ data were similarly treated and plotted on the same graph for comparison. Generally, the treated metallic bipolar plate provided at least a 22% savings in hydrogen consumption in comparison to graphite. This is attributed to the lower bulk and surface contact resistance of the coated aluminum plates used in this study in relation to graphite. The results of the lifetime testing conducted at 70 °C cell temperature under cyclic loading condition showed no indication of power degradation due to metal corrosion for at least 1000 h.

Desalination is a highly complex process, which requires an efficient and accurate control system in the plant to maintain operation at optimum conditions that result in energy savings and in preventing scale formation. A study of a multi-input multi-output (MIMO) control of mechanical vapour compression desalination systems is presented. A transient model was developed to describe the significant dynamics of a vapour compression desalination system. A dynamic model was simulated using the Matlab program to provide physical insight into the system's dynamic behavior. Two efficient PID controllers for both distillate and evaporation temperature were developed to attain good performance.

This study investigated the corrosion stability of high velocity oxy‐fuel (HVOF) spray SUS316L coatings on aluminium substrate as lightweight bipolar plate materials for proton exchange membrane fuel cells (PEMFC). Contact resistance, microhardness and structure of the coatings were characterised using a four‐point probe, pneumatic microhardness, XRD and scanning electron microscope techniques. Preliminary electrochemical results indicate that the SUS316L coated plates significantly lowered the corrosion current of the aluminium substrate by more than one order of magnitude. Corrosion stability in relation to the coating thickness is discussed in terms of the structure composition and transpassivity of chromium.

A multifunctional catalyst may represent a valid route to enhance methanol electro-oxidation. Ternary catalysts based on Pt modified with both Ru and Ir oxides show better performance for methanol electro-oxidation than bi-metallic Pt-Ru catalysts. This journal is © the Partner Organisations 2014.

Electro-catalytic oxidation of methanol is known to be promoted on Pt-Ru and Pt-Sn surfaces. Whilst Ru addition to Pt has been unambiguously acknowledged to enhance the methanol-oxidation reaction, the effect of Sn in the Pt-Sn alloy remains shrouded with inconsistencies. In order to further elucidate this problem, an X-ray photoelectron spectroscopic study is carried out on various carbon-supported Pt-Ru and Pt-Sn catalysts. It is argued that while Sn produces a modification in electronic environment around Pt-sites through a charge transfer in the Pt-Sn alloy, Ru-sites in the Pt-Ru system promote the formation of labile-bonded oxygenated species in the vicinity of methanolic residues adsorbed on Pt-sites facilitating them to oxidise as carbon-di-oxide.