Biofuel cells Research Papers - Academia.edu (original) (raw)

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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Biofuel cells are similar to traditional fuel cells, except the metallic electrocatalyst is replaced with a biological electrocatalyst. This paper details the development of an enzymatic biofuel cell, which employs alcohol dehydrogenase to oxidize ethanol at the anode and bilirubin oxidase to reduce oxygen at the cathode. This ethanol/oxygen biofuel cell has an active lifetime of about 30 days and shows power densities of up to 0.46 mW/cm 2 . The biocathode described in this paper is unique in that bilirubin oxidase is immobilized within a modified Nafion polymer that acts both to entrap and stabilize the enzyme, while also containing the redox mediator in concentrations large enough for self-exchange based conduction of electrons between the enzyme and the electrode. This biocathode is fuel tolerant, which leads to a unique fuel cell that employs both renewable catalysts and fuel, but does not require a separator membrane to separate anolyte from catholyte.

- by Shelley Minteer
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- Biofuel cells

ABSTRACT Enzyme catalysis: Three dehydrogenases have been engineered to self-assemble into a hydrogel that supports a synthetic metabolic network. The new catalytic biomaterial was used as an anode modification in two enzymatic... more

- by Scott Banta
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- Carbon Dioxide, Kinetics, Protein Engineering, Biocatalysis

The biofuel industry is rapidly growing with a promising role in producing renewable energy and tackling climate change. Nanotechnology has tremendous potential to achieve cost-effective and process-efficient biofuel industry. Various nanomaterials have been developed with unique properties for enhanced biofuel production/utilization. The way forward is to develop nanotechnology-based biofuel systems at industrial scale.

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Biochemistry, Environmental Science

Biomass pyrolysis is a promising renewable sustainable source of fuels and petrochemical substitutes. It may help in compensating the progressive consumption of fossil-fuel reserves. The present article outlines biomass pyrolysis. Various types of biomass used for pyrolysis are encompassed, e.g., wood, agricultural residues, sewage. Categories of pyrolysis are outlined, e.g., flash, fast, and slow. Emphasis is laid on current and future trends in biomass pyrolysis, e.g., microwave pyrolysis, solar pyrolysis, plasma pyrolysis, hydrogen production via biomass pyrolysis, co-pyrolysis of biomass with synthetic polymers and sewage, selective preparation of high-valued chemicals, pyrolysis of exotic biomass (coffee grounds and cotton shells), comparison between algal and terrestrial biomass pyrolysis. Specific future prospects are investigated, e.g., preparation of supercapacitor biochar materials by one-pot one-step pyrolysis of biomass with other ingredients, and fabricating metallic catalysts embedded on biochar for removal of environmental contaminants. The authors predict that combining solar pyrolysis with hydrogen production would be the eco-friendliest and most energetically feasible process in the future. Since hydrogen is an ideal clean fuel, this process may share in limiting climate changes due to CO 2 emissions.
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel

- by Prof Dr Yehia Fahmy and +2
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- Environmental Engineering, Environmental Science, Development Economics, Environmental Economics
- by Bren Bustamante Valles
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Diminishing fossil fuel resources, unstable/increasing prices of oil, environmental issues, global warming/climatic shifts, and allied problems have led the world to focus on alternate, environmental friendly, and renewable energy sources. Among many experimental candidates, production of biodiesel from Jatropha curcas L. has gained significant importance. More than 40 countries in the world are evaluating the potential of using this pure plant oil for manufacturing diesel. USEPA's action sets the 2013 volume at 1.28 billion gallons under the Energy Independence and Security Act of 2007. With this premise, it is imperative to identify innovative technologies to handle Jatropha biomass and its efficient oil extraction for economical biofuel production. This study is aimed to make efficient screw expeller to cater massive Jatropha biomass for its oil extraction. A computational flow dynamics (CFD) simulation is performed to estimate the pressure developed inside the barrel through screw pressing when the feedstock is Jatropha seed. This CFD study has helped to determine the optimum values of important operating variables like rotations per minute (rpm), backpressure caused by frictional forces, and effect of changing feed flow rate on the performance of the expeller. The performance of the expeller is measured by power consumption, yield, and efficiency. Experimental validation of the simulation is used to improve oil expeller for Jatropha seed by fabricating the expeller after the analysis of design by ANSYS FLUENT codes. An oil yield in excess of 98%, as compared to a maximum 75% for existing screw expellers, was achieved in practical runs which is very promising.

- by Mehran Khan
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- Engineering, Chemical Engineering, Membranes, Catalysis
- by Ahmed A Abdala
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Addressing the contemporary waste management is seeing a shift towards energy production while managing waste sustainably. Consequently, waste treatment through gasification is slowly taking over the waste incineration with multiple benefits, including simultaneous waste management and energy production while reducing landfill volumes and displacing conventional fossil fuels. Only in the UK, there are around 14 commercial plants built to operate on gasification technology. These include fixed bed and fluidized bed gasification reactors. Ultra-clean tar free gasification of waste is now the best available technique and has experienced a significant shift from two-stage gasification and combustion towards a one-stage system for gasification and syngas cleaning. Nowadays in gasification sector, more companies are developing commercial plants with tar cracking and syngas cleaning. Moreover, gasification can be a practical scheme when applying ultra-clean syngas for a gas turbine with heat recovery by steam cycle for district heating and cooling (DHC) systems. This chapter aims to examine the recent trends in gasification-based waste-to-energy technologies. Furthermore, types of gasification technologies, their challenges and future perspectives in various applications are highlighted in detail.

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Chemistry
- by ALEX IBHADON
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- Chemical Engineering, Physical Chemistry, Membranes, Catalysis
- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Energy Economics
- by Zubia Saleem
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Nanoporous gold (NPG) obtained via dealloying of Au alloys has potential applications in a range of fields, and in particular in bioelectrochemistry. NPG possesses a three dimensional bicontinuous network of interconnected pores with typical pore diameters of ca. 30-40 nm, features that are useful for the immobilisation of enzymes. This review describes the common routes of fabrication and characterization of NPG, the use of NPG as a support for oxidoreductases for applications in biosensors and biofuel cells together with recent progress in the use of NPG electrodes for applications in bioelectrochemistry.

- by xx xiao and +2
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- Bioelectrochemistry, Biofuel cells, Glucose Sensors, Nanoporous Gold

This review focuses on recent advances in micro-and nano-fabrication techniques and their applications to electrochemical power devices, specifically microfabricated Lithium-ion batteries, enzymatic and microbial fuel cells (biofuel cells), and dye-sensitized solar cells (DSSCs). Although the maturity of these three technologies ranges from market ready (batteries) to fundamental research (biofuel cells) to applied research (DSSCs), advances in MEMS (Micro-Electro-Mechanical Systems) and NEMS (Nano-Electro-Mechanical Systems) techniques, particularly modifications in surface area and surface chemistry, and novel genetic and molecular engineering techniques, significantly improve the electrochemical activity of these technologies across the board. For each of these three categories of power-MEMS devices the review covers: (1) The technical challenges facing the performance and fabrication of electrochemical power devices; (2) Current MEMS and NEMS techniques used to improve efficiency; and (3) Future outlook and suggested improvements of MEMS and NEMS for implementation in electrochemical power devices.

- by Lawrence Kulinsky
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- Dye Sensitized Solar Cells, Nanotechnology, Lithium Ion Battery, Biofuel cells

A sustainable transition is premised upon moving from a carbon energy regime to a renewable energy regime; a highly contested political-economic transformation, to say the least. In places like the United States and European Union the main form of renewable energy is bioenergy, especially biofuels. Recent policy and industry efforts are focusing on the development and implementation of what are known as ‘drop-in’ biofuels, so named because they can be incorporated into existing distribution infrastructure (e.g. pipelines) and conversion devices with relatively few, if any, technical modifications. As with carbon energy, bioenergy has particular materialities that are implicated in the political-economic possibilities and constraints facing societies around the world. These political materialities of bioenergy shape and are shaped by new energy regimes and therefore problematize the notion of a drop-in biofuel. Thus further examination of the political materialities of bioenergy, and of renewable energy more generally, is of critical importance for successful sustainable transitions.

- by Kean Birch and +1
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- Geography, Human Geography, Social Geography, Environmental Geography
- by Inam Bhatti
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Among the most pressing energy and environmental strategic challenges today is to identify and deploy viable alternatives to fossil-fuel-based energy systems The barriers to deployment are systematic, leading to a state of affairs described as ‘carbon lock-in’ (Unruh
2000; Neuhoff 2007). Simply stated, even if alternative energy systems are cost-competitive in theory, the prime movers that control their diffusion throughout society –
for example, conversion and distribution infrastructure; financing mechanisms; skilled labour force; attitudes toward particular kinds of energy production activities and energy services – exhibit a preference for incumbent carbon-intensive fossil energy resources. Carbon lock-in represents path dependencies within energy systems including sunk-cost in prevailing infrastructure and entrenched political interests along with positively reinforcing relationships with broader system dynamics, from global financial logics that continue to monetise unburned carbon through energy
futures contracts to our everyday practices and expectations about mobility, comfort, and overall
well-being that underpin regular visits to the gasoline station. All of this is to say that energy systems are sociotechnical in nature, characterised by deep and often subtle interdependencies between technological, social, political-economic, and cultural processes which operate across the energy supply chain and at all scales of energy system operation (Miller, Richter, and O’Leary 2015).

- by Kean Birch
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- Bioengineering, Geography, Human Geography, Political Geography and Geopolitics

The present study aimed to the investigation of the feasibility of the combined biohydrogen and biopolymers production from OMW (Olive oil Mill Wastewater), using a two stage system. H2 and volatile fatty acids (VFAs) were produced via anaerobic fermentation and subsequently the acidified wastewater was used as substrate for aerobic biodegradable polymer production. Two different bioreactors, one of CSTR type and a SBR were used for the anaerobic and the aerobic process respectively. The anaerobic reactor was operated at different hydraulic retention times (HRTs) with OMW, diluted 1:4 (v/v) with tap water, as feed. The main VFAs produced were acetate, butyrate and propionate, in different ratios depending on the HRT. Valerate, isovalerate and isobutyrate were also detected in small quantities. Selective effluents of the acidogenic/hydrogen producing reactor were subsequently used as feed for the aerobic reactor. The aerobic reactor was inoculated with an enriched PHAs producing bacteria culture, and was operated in sequential cycles of nitrogen offer (growth phase) and nitrogen limitation (PHAs accumulation phase). The operational program of the SBR was determined according to the results from batch test, and its performance was evaluated for a period of 100 days. During the accumulation phase butyrate was consumed preferably, indicating that the dominant PHA produced is polyhydroxybutyrate. The higher yield of PHAs observed was 8.94% (w/w) of dry biomass weight.

A B S T R A C T The integration of supercapacitors with enzymatic biofuel cells (BFCs) can be used to prepare hybrid devices in order to harvest significantly higher power output. In this study, a supercapacitor/biofuel cell hybrid device was prepared by the immobilisation of redox enzymes with electrodeposited poly(3,4-ethylenedioxythiophene) (PEDOT) and the redox polymer [Os(2,2′-bipyridine) 2 (polyvinylimidazole) 10 Cl] +/2+ (Os(bpy) 2 PVI) on dealloyed nanoporous gold. The thickness of the deposition layer can be easily controlled by tuning the deposition conditions. Once charged by the internal BFC, the device can be discharged as a supercapacitor at a current density of 2 mA cm −2 providing a maximum power density of 608.8 μW cm −2 , an increase of a factor of 468 when compared to the power output from the BFC itself. The hybrid device exhibited good operational stability for 50 charge/discharge cycles and ca. 7 h at a discharge current density of 0.2 mA cm −2. The device could be used as a pulse generator, mimicking a cardiac pacemaker delivering pulses of 10 μA for 0.5 ms at a frequency of 0.2 Hz.

- by xx xiao
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- Biofuel cells, Nanoporous Materials

The use of akernattve fuels from renewable vegetable sources has become increasingly widespread in recent yeats. In addition to other olternative fuels srch as ethanol, methanol or biogas (methane), fatty acid methyl esters are irs*v**singly being found on the market; these are eetso Imown as biodiesel or FAME (fotty acid '*aee&zyl esters). Fatty acid metlryl esters ire uswlly obtained from oil seeds and mainly used in their pureform or mixedwith corumtional dieselfuel in the transport sector. During manufacture the vegetable oil is trawesterified with methanol. This produces the metlryl esters of the fatty acids present in the oil together with glycerol as a by-pro&rct. Methanol concentrotion itself influence to some aspects in biodiesel such as conversion, yield, and quality. This paper discussed in daail. trFased on this study, as the methanol concmtration increased, which the yield of biodiesel and esther €{xrtent were also increased, while the total g€,3,cerol ond acid value were found to be decreased.

- by Oni Fariza
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- Environmental Engineering, Chemical Engineering, Membranes, Catalysis

Current separation, isolation and purification techniques to obtain highly potent purified
lactobacilli and lactococcoi bacteriocins include chemical precipitation, separation employing solvents
and chromatographic techniques. These methods are arduous, costly, with limited scalability, offering
low bacteriocin yields (<20%). To address these challenges, the alternatives of ultrafiltration and
nanofiltration, as separation methods were tested. Three promising bacteriocin producing strains,
Lactobacillus casei NCIMB 11970, Lactobacillus plantarum NCIMB 8014 and Lactococcus lactis NCIMB
8586 were selected to investigate the applicability and feasibility of the method.
To facilitate separation, the microorganisms were grown on specially developed low molecular weight
medium (LMWM) mainly containing nutritive sources up to 4 kDa molecular weight. Bacterial cells
were removed by centrifugation. The clarified broths were filtered using 4 and 1 kDa MWCO.
Bacteriocin activity was determined by an antimicrobial activity test using nisin, which has an
inhibitory effect on the growth of susceptible microorganisms. Recovery yields using filtration were
found to range between 53 to 68%, a high recovery performance.
The bacteriocin activity of crude extracts of all the three lactobacilli were between 95-105 IU ml-1.
When the substances were separated using ultrafiltration membrane (4kDa MWCO) their activity was
enhanced to 145-150 IU ml-1, achieving a total potency yield of 44% to 53%. Further enhancement of
yields up to 36% was attained employing nanofiltration (1 kDa MWCO) membranes with an activity
increased up to 200 IU ml-1.
Bacteriocin isolation from crude extracts using filtration was found to be effective, offering high
recovery yields, optimizing their activity as well as presenting a realistic option towards the
formulation of these as commercially available antibacterial agents.

- by Myrto-Panagiota Zacharof and +1
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- Engineering, Environmental Engineering, Chemical Engineering, Chemical Education

In this review, recent developments in fine chemicals synthesis, catalysis, microreactor design and applications are discussed. Specifically, new advances in continuous micro process engineering, packedbed devices and photoreactors are discussed to include recent patents in these areas. In addition, new energy sources including ultrasounds and microwaves integrated into microstructured reactors are shown accordingly. Novel progresses in materials to build these devices such as single walled nanotubes are discussed with respect to their properties and synthesis. This approach foresees developments in in the use of nanomaterials in microreactor design and the impact these will have in the synthesis and purification of different fine chemicals in continuous flow devices.

- by ALEX IBHADON
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes including microfiltration and nanofiltration to concentrate volatile fatty acids. Microfiltration was applied successfully to produce sterile, particle free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These, were further treated using a variety of nanofiltration membranes (NF270, (Dow Chemicals, USA), HL, DL, DK, (Osmonics , USA), LF10 (Nitto Denko, Japan) achieving retention ratios, up to 75% giving retentates up to 53.94 mM acetate and 28.38 mM butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions highest productivity, retention and flux was achieved at pH 7 at higher pH there was a significant reduction in flux.

- by Myrto-Panagiota Zacharof
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- Chemical Engineering, Water, Membranes, Water resources

Highly stretchable textile-based biofuel cells (BFCs), acting as effective self-powered sensors, have been fabricated using screen-printing of customized stress-enduring inks. Due to synergistic effects of nanomaterial-based engineered inks and the serpentine designs, these printable bioelectronic devices endure severe mechanical deformations, e.g., stretching, indentation, or torsional twisting. Glucose and lactate BFCs with the single enzyme and membrane-free configurations generated the maximum power density of 160 and 250 µW cm−2 with the open circuit voltages of 0.44 and 0.46 V, respectively. The textile-BFCs were able to withstand repeated severe mechanical deformations with minimal impact on its structural integrity, as was indicated from their stable power output after 100 cycles of 100% stretching. By providing power signals proportional to the sweat fuel concentration, these stretchable devices act as highly selective and stable self-powered textile sensors. Applicability to sock-based BFC and self-powered biosensor and mechanically compliant operations was demonstrated on human subjects. These stretchable skin-worn “scavenge-sense-display” devices are expected to contribute to the development of skin-worn energy harvesting systems, advanced non-invasive self-powered sensors and wearable electronics on a stretchable garment.

- by Itthipon Jeerapan and +1
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- Textiles, Biosensors, Wearable sensors, Glucose

Electricity generation in a duel chamber microbial fuel cell (MFC) consisting of graphite anode electrode, platinum cathode electrode and Nafion 117 membrane was investigated. Anaerobic sludge was used as the source of microorganisms in the anode
chamber. Acetic acid as the sole carbon source along with other nutrients was added to the anode chamber in a batch or repeated-batch modes. System curves and polarization curves were obtained in different operational conditions and the internal resistance of the system was calculated. Electricity generation by MFC in both batch and repeated-batch modes was modeled using a biofilm based hypothesis and the results were compared with experimental data.

Hardness in water, which is caused by divalent cations such as calcium and magnesium ions, presents a major water quality problem. Because hard water must be softened before use in residential applications, there is great interest in the saltless water softening process because, unlike ion exchange softeners, it does not introduce additional ions into water. In this study, a saltless hardness removal driven by bioelectrochemical energy produced through enzymatic oxidation of glucose was proposed and investigated. Glucose dehydrogenase was coated on a carbon electrode to catalyze glucose oxidation in the presence of NAD + as a cofactor/mediator and methylene green as an electrocatalyst. The results showed that electricity generation stimulated hardness removal compared with non-electricity conditions. The enzymatic water softener worked upon a 6 h batch operation per day for eight days, and achieved an average hardness removal of 46% at a high initial concentration of 800 mg/L as CaCO 3 . More hardness was removed at a lower initial concentration. For instance, at 200 mg/L as CaCO 3 the enzymatic water softener removed 76.4 ± 4.6% of total hardness. The presence of magnesium ions decreased hardness removal because of its larger hydrated radius than calcium ions. The enzymatic water softener removed 70-80% of total hardness from three actual hard water samples. These results demonstrated a proof-of-concept that enzyme catalyzed electricity generation can be used to soften hard water.

- by Shelley Minteer
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- Biofuel cells

Quaternary ammonium bromide salt-treated Nafion membranes provide an ideal environment for enzyme immobilization. Because these quaternary ammonium bromide salt-treated Nafion membranes retain the physical properties of Nafion and increase the mass transport of ions and neutral species through the membrane, they are also ideal for modifying electrodes. Therefore, high current density bioanodes are formed from poly(methylene green) (an electrocatalyst for NADH) modified electrodes that have been coated with a layer of tetrabutylammonium bromide salt-treated Nafion with dehydrogenase enzymes immobilized within the layer. Ethanol/O 2 biofuel cells employing these bioanodes have yielded power densities of 1.16 mW/cm 2 with a single-enzyme system (alcohol dehydrogenase) and 2.04 mW/cm 2 with a double-enzyme system (alcohol dehydrogenase and aldehyde dehydrogenase) in the polymer layer. Methanol/O 2 biofuel cells employing these bioanodes have yielded power densities of 1.55 mW/cm 2 and open circuit potentials of 0.71 V.

Bio-electrochemical degradation of pentachlorophenol was carried out in single as well as dual chambered microbial fuel cell (MFC) with simultaneous production of electricity. The maximum cell potential was recorded to be 787 and 1021 mV in single and dual chambered systems respectively. The results presented nearly 66 and 89% COD removal in single and dual chambered systems with corresponding power densities of 872.7 and 1468.85 mW m À2 respectively. The highest coulombic efficiency for single and dual chambered counterparts was found to be 33.9% and 58.55%. GC-MS data revealed that pentachlorophenol was more effectively degraded under aerobic conditions in dual-chambered MFC. Real-time polymerase chain reaction showed the dominance of exoelectrogenic Geobacter in the two reactor systems with a slightly higher concentration in the dual-chambered system. The findings of this work suggested that the aerobic treatment of pentachlorophenol in cathodic compartment of dual chambered MFC is better than its anaerobic treatment in single chambered MFC in terms of chemical oxygen demand (COD) removal and output power density.

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Biochemistry, Environmental Science
- by Lewis Ezeogu
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- Bioinformatics, Food Safety, Biotechnology, Food Chemistry

The regeneration of the enzymatic cofactor nicotinamide adenine dinucleotide (NADH) by rhodium-based catalysts such as [Rh(Cp * )(bpy)Cl] + (Cp * = pentamethylcyclopentadienyl, bpy = 2,2 -bipyridine) and derivatives have previously been studied extensively in solution. In this work, we report a synthetic route of a rhodium complex with a pyrene-substituted phenanthroline ligand (pyr-Rh). The immobilization of the pyr-Rh complex was accomplished on multi-walled carbon nanotubes (MWCNTs) via π-π stacking to obtain effective and durable indirect electrochemical regeneration of NADH. Cyclic voltammetry and amperometry were used to demonstrate the electrochemical activity of the surface-confined pyr-Rh complex. The loading quantity of the pyr-Rh complex was found to be 47 ± 2 nmol/mg of MWCNTs. The reusability of the electrodes modified with the pyr-Rh complex was investigated and an average turnover frequency of 3.6 ± 0.1 s −1 over ten cycles in the presence of 2 mM nicotinamide adenine dinucleotide (NAD + ) was observed. Lastly, malate dehydrogenase (MDH), a NADH-dependent enzyme, was evaluated in the presence of the immobilized pyr-Rh complex to confirm the catalyst's capability to regenerate biologically active NADH for biocatalysis.

- by Fabien Giroud
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- Materials Engineering, Electrocatalysis, Biofuel cells

Biocatalytic electrodes made of buckypaper were modified with PQQ-dependent glucose dehydrogenase on the anode and with laccase on the cathode and were assembled in a flow biofuel cell filled with serum solution mimicking the human blood circulatory system. The biofuel cell generated an open circuitry voltage, V oc , of ca. 470 mV and a short circuitry current, I sc , of ca. 5 mA (a current density of 0.83 mA cm À2 ). The power generated by the implantable biofuel cell was used to activate a pacemaker connected to the cell via a charge pump and a DC-DC converter interface circuit to adjust the voltage produced by the biofuel cell to the value required by the pacemaker. The voltage-current dependencies were analyzed for the biofuel cell connected to an Ohmic load and to the electronic loads composed of the interface circuit, or the power converter, and the pacemaker to study their operation. The correct pacemaker operation was confirmed using a medical device -an implantable loop recorder. Sustainable operation of the pacemaker was achieved with the system closely mimicking human physiological conditions using a single biofuel cell. This first demonstration of the pacemaker activated by the physiologically produced electrical energy shows promise for future electronic implantable medical devices powered by electricity harvested from the human body.

- by Lenka Halamkova
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- Biofuel cells

In this study, the flow behavior of multi-walled carbon nanotubes (CNTs) reinforced copper matrix feedstocks is presented. The solid loadings in the copper feedstock were investigated in the ranges of 55-61 Vol.% using binder. Pure copper (Cu) and Cu/CNTs feedstocks were compounded using internal mixer machine for homogenous dispersion of solids in the binder. The flow behavior were measured using a capillary rheometer in the shear rate range expected to occur during powder injection molding. An acceptable increasing trend in viscosity of the copper feedstock with powder loading was recorded. Cu/CNTs composite feedstocks showed viscosity more than 1000 Pa.s which is most probably due to the addition of CNTs and increasing trend in viscosity of Cu/CNTs was noted as well. The results also identified that the feedstock containing 59 vol.% copper was most suitable for substitution of CNTs in Cu feedstock.

- by Ali Samer
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- Chemical Engineering, Materials Science, Ergonomics, Composite Materials and Structures

Low-temperature methane and methanol steam-reforming catalysts with various loadings of Ni and Cu were prepared using a wet impregnation method. The samples were characterized using scanning electron microscope, surface area (BET) test, X-ray diffraction (XRD), infrared test, CO chemisorption test and temperature-programmed reduction tests. XRD testing showed that NiO and CuO were present. Ni-Cu-alloyed catalyst shows a significant change in the catalyst characteristics compared with those of individual metals. The results presented in this paper show the main changes in the catalyst properties using ex situ testing.

- by Marcin Khzouz
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- Chemical Engineering, Hydrogen, Membranes, Catalysis

Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approach to heavy metal ion adsorbents based on the covalent grafting of MPTMS groups to the framework pore walls of mesoporous silica molecular sieves has been developed and investigated with regard to hydroxyl group densities, channel dimensions, morphologies and reaction conditions. Results show that the ordered mesostructures of functionalized samples were retained after modification and the thiol functional group was immobilized mainly inside the mesopore channel. The relative surface coverage of the monolayer can be systematically varied up to 95%. The functionalized hybrid materials show exceptional selectivity and capacity for removing mercury from aqueous waste stream with distribution coefficients up to 435,000. The regenerated material show high mercury ion uptake capacity of 2.87 mmol/g (86.5%).

- by Inam Bhatti
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- Chemical Engineering, Membranes, Catalysis, Nanocomposites

In this work, the ultrafiltration of macromolecules was analysed using a response surface methodological approach. The behaviour of two different inorganic membranes was investigated. The membranes selected were a Carbosep M2 membrane (Orelis, France) with a molecular weight cut-off (MWCO) of 15 kDa and a Tami MSKT membrane (Tami Industries, France) with a MWCO of 5 kDa. The solute employed was polyethylene glycol of 35 kDa molecular weight. The influence of transmembrane pressure (0.1, 0.2, 0.3, 0.4 and 0.5 MPa), crossflow velocity (1, 2 and 3 m/s) and feed concentration (5, 10 and 15 g/L) on permeate flux and permeate flux decline was investigated. Analysis of variance was proved to be a useful tool to determine the effect of operating variables on both parameters. The method used demonstrated the presence of coupled effects between factors as well as squared effects that are relevant to the ultrafiltration process. The surface contours obtained from fitted models were used for the optimization of the operating conditions. The goal was to simultaneously maximize the average permeate flux and minimize the flux decline. The optimal operating conditions for the Carbosep M2 membrane were a transmembrane pressure of 0.38 MPa and a crossflow velocity of 3 m/s. The optimal operating conditions for the Tami MSKT membrane could not be determined by means of multiple response optimization due to the low accuracy of the regression model obtained for the cumulative permeate flux decline (SFD) response variable.

- by Silvia Alvarez Blanco
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- Chemical Engineering, Membrane Science, Membranes, Catalysis

Glucose substrates are successfully harnessed to generate electricity in a membraneless biofuel cell with a mesh network of carbon nanotubes pyroquinoline quinone glucose dehydrogenase-modified anode and a laccase-modified cathode. Using glucose as a substrate, this glucose-oxygen biofuel cell is able to produce a steady current density of 337.5 µA/cm² and an open circuit voltage of 524 mV in 360 mg/dL glucose solution. Interestingly, the fuel cell in combination with a capacitor as the transducer element can also be utilized as a glucose monitor while generating electricity simultaneously to power small electronic devices, such as light emitting diode (LED). Moreover, the self-powered glucose monitor exhibited a linear dynamic range of 9 mg/dL to 630 mg/dL glucose. These results and device demonstrations suggest that further research into self-powered glucose monitors can provide major benefit in developing a novel autonomous implantable glucose monitor platform to greatly improve the quality of life for individuals living with diabetes.

- by Gymama Slaughter
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- Diabetes, Glucose, Voltage Stability, Continuous Glucose Monitoring