scholarly journals Repurposing Inflatable Packaging Pillows as Bioreactors: a Convenient Synthesis of Glucosone by Whole-Cell Catalysis Under Oxygen

2020 ◽  
Author(s):  
Michael D. Mozuch ◽  
Kolby C. Hirth ◽  
Thomas J. Schwartz ◽  
Philip J. Kersten
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Preparative Synthesis ◽  
Resting Cells ◽  
Whole Cells ◽  
Convenient Synthesis ◽  
Mechanical Methods ◽  
Parallel Reactions

AbstractBiocatalysis using molecular oxygen as the electron acceptor has significant potential for selective oxidations at low cost. However, oxygen is poorly soluble in water, and its slow rate of mass transfer in the aqueous phase is a major obstacle, even for laboratory-scale syntheses. Oxygen transfer can be accelerated by vigorous mechanical methods, but these are often incompatible with biological catalysts. Gentler conditions can be achieved with shallow, high surface area bag reactors that are designed for single use and generally for specialized cell culture applications. As a less-expensive alternative to these high-end bioreactors, we describe repurposing inflatable shipping pillows with resealable valves to provide high surface area mixing under oxygen for preparative synthesis of glucosone (D-arabino-hexos-2-ulose) from D-glucose using non-growing Escherichia coli whole cells containing recombinant pyranose 2-oxidase (POX) as catalyst. Parallel reactions permitted systematic study of the effects of headspace composition (i.e., air vs 100% oxygen), cell density, exogenous catalase, and reaction volume in the oxidation of 10% glucose. Importantly, only a single charge of 100% oxygen is required for stoichiometric conversion on a multi-gram scale in 18 h with resting cells, and the conversion was successfully repeated with recycled cells.

Morphology dependent adsorption of methylene blue on trititanate nanoplates and nanotubes prepared by the hydrothermal treatment of TiO2

2016 ◽  
Vol 75 (2) ◽  
pp. 350-357
Author(s):  
Graham Dawson ◽  
Wei Chen ◽  
Luhua Lu ◽  
Kai Dai
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Pore Volume ◽  
Hydrothermal Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
High Capacity ◽  
Adsorption Properties

The adsorption properties of two nanomorphologies of trititanate, nanotubes (TiNT) and plates (TiNP), prepared by the hydrothermal reaction of concentrated NaOH with different phases of TiO2, were examined. It was found that the capacity for both morphologies towards methylene blue (MB), an ideal pollutant, was extremely high, with the TiNP having a capacity of 130 mg/g, higher than the TiNT, whose capacity was 120 mg/g at 10 mg/L MB concentration. At capacity, the well-dispersed powders deposit on the floor of the reaction vessel. The two morphologies had very different structural and adsorption properties. TiNT with high surface area and pore volume exhibited exothermic monolayer adsorption of MB. TiNP with low surface area and pore volume yielded a higher adsorption capacity through endothermic multilayer adsorption governed by pore diffusion. TiNP exhibited a higher negative surface charge of −23 mV, compared to −12 mV for TiNT. The adsorption process appears to be an electrostatic interaction, with the cationic dye attracted more strongly to the nanoplates, resulting in a higher adsorption capacity and different adsorption modes. We believe this simple, low cost production of high capacity nanostructured adsorbent material has potential uses in wastewater treatment.

Highly active mixed-valent MnOxspheres constructed by nanocrystals as efficient catalysts for long-cycle Li–O2batteries

2016 ◽  
Vol 4 (43) ◽  
pp. 17129-17137 ◽  
Author(s):  
Sanpei Zhang ◽  
Zhaoyin Wen ◽  
Yang Lu ◽  
Xiangwei Wu ◽  
Jianhua Yang
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Long Cycle ◽  
Highly Active

We demonstrate a low-cost and facile strategy to synthesize mixed-valent MnOxspheres constructed from nanocrystals (~5 nm), containing MnII, MnIII, and MnIVspecies. Such highly active mixed-valent MnOxspheres with high surface area greatly improve the performance of Li–O2batteries.

Reduction of bis(Oxalato)Borate on a High Surface Area Carbon Electrode

2008 ◽  
Vol 1127 ◽  
Author(s):  
John Flynn ◽  
Carl Schlaikjer
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Potential Range ◽  
Electrolytic Properties ◽  
Extensive Exchange ◽  
Soluble Species ◽  
Wide Potential

ABSTRACTLithium bis(oxalato)borate (LiBOB) has gained widespread interest as an electrolyte salt for lithium ion batteries because of its high conductivity, low cost, thermal stability, and adequate solubility in many organic solvents [1]. Cyclic voltammetric data taken on platinum [2] and carbon [3] indicate electrochemical stability over a wide potential range.We show that bis(oxalato)borate (BOB) can be reduced at about 1.75 volts anodic to lithium, by discharging electrolytes at low current density (0.1 mA/cm2) on high surface area carbon electrodes containing a mixture of acetylene and Ketjen carbon blacks. The evidence includes discharge profiles and 11B NMR data. The behavior of discharge plateaus indicates that BOB is reduced to a soluble species with electrolytic properties, and the appearance of a broad 11B NMR peak in the electrolyte indicates that the reduced species undergoes extensive exchange.

scholarly journals Silica Nanoparticles for Biomedical Application: Challenges and Opportunities

2020 ◽  
Author(s):  
E.A. Mun ◽  
B.A. Zhaisanbayeva
Keyword(s):  
Silica Nanoparticles ◽  
Surface Area ◽  
Biomedical Application ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Drug Carriers ◽  
High Reactivity ◽  
Diagnostic Tools ◽  
Gene Delivery Vectors

Over the past few decades, nanoparticles have been attracting significant attention of researches in chemical, biomedical, pharmaceutical sciences, due to their unique physicochemical properties. This includes ultra small size, large surface area, good biocompatibility and high reactivity. In particular, nanoparticles are promising for pharmaceutical and biomedical fields, as they can be applied as drug carriers and diagnostic tools. Among nanomaterials for biomedical application, silica nanoparticles exhibit great potential due to their straightforward synthesis and separation, low cost, safety, biocompatibility and possibility to further functionalization. Silica nanoparticles have been attractive for pharmaceutical science due to their unique properties, such as tunable size, high surface area and large pore volume, and potential in biomedical application as drug and gene delivery vectors and bioimaging agents. However, some of their properties remain poorly investigated. This short communication discusses the main routes for synthesis of silica nanoparticles, their properties and opportunities for their application in pharmaceutical and biomedical industries, as well as a few challenges in the development of silica-based systems that need to be overcome.

Low voltage electrolyte-gated organic transistors making use of high surface area activated carbon gate electrodes

2014 ◽  
Vol 2 (28) ◽  
pp. 5690-5694 ◽  
Author(s):  
J. Sayago ◽  
F. Soavi ◽  
Y. Sivalingam ◽  
F. Cicoira ◽  
C. Santato
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Low Voltage ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Reference Electrode ◽  
Organic Transistors ◽  
Gate Electrodes ◽  
External Reference

The use of high surface area, low cost, activated carbon gate electrodes enables low voltage (sub-1 V) operation in ionic liquid-gated organic transistors and renders unnecessary the presence of an external reference electrode to monitor the channel potential.

Preparation and Characterization of Rice Husk Ash for Adsorption of Phenol from Aqueous Solutions

2014 ◽  
Vol 625 ◽  
pp. 498-502
Author(s):  
Samah B. Daffalla ◽  
Hilmi Mukhtar ◽  
Maizatul S. Shaharun
Keyword(s):  
Aqueous Solutions ◽  
Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Physiochemical Properties ◽  
Pseudo Second Order

In this research, the development of three (3) low-cost adsorbent materials from abundant waste rice husk was achieved via thermal treatment. The physiochemical properties of the developed adsorbents were evaluated. Their adsorption behaviours in batch system were evaluated for the removal of phenol from aqueous solutions by varying the pH (2 to 10). It was found that, the rice husk ash burned a 400oC for 1hr ‘RHA400,1’ has the highest surface area (201.36 m2.g-1) followed by RHA300,4(87.08 m2.g-1) and RHA600,1(43.22 m2.g-1), respectively. RHA400,1had shown the highest removal efficiency followed by RHA300,4and RHA600,1, towards phenol due to high surface area and porosity. The maximum uptake of phenol was found at pH 4. The adsorption kinetics was well described by both pseudo-second order and the Elovich models.

scholarly journals Modification of Microelectrode Arrays with High Surface Area Dendritic Platinum 3D Structures: Enhanced Sensitivity for Oxygen Detection in Ionic Liquids

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 735 ◽  
Author(s):  
Ghulam Hussain ◽  
Anthony O’Mullane ◽  
Debbie Silvester
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
3D Structures ◽  
Surface Areas ◽  
Enhanced Sensitivity ◽  
Redox Active ◽  
Low Concentrations ◽  
One Step

Electrochemical gas sensors are often used for identifying and quantifying redox-active analyte gases in the atmosphere. However, for amperometric sensors, the current signal is usually dependent on the electroactive surface area, which can become small when using microelectrodes and miniaturized devices. Microarray thin-film electrodes (MATFEs) are commercially available, low-cost devices that give enhanced current densities compared to mm-sized electrodes, but still give low current responses (e.g., less than one nanoamp), when detecting low concentrations of gases. To overcome this, we have modified the surface of the MATFEs by depositing platinum into the recessed holes to create arrays of 3D structures with high surface areas. Dendritic structures have been formed using an additive, lead acetate (Pb(OAc)2) into the plating solution. One-step and two-step depositions were explored, with a total deposition time of 300 s or 420 s. The modified MATFEs were then studied for their behavior towards oxygen reduction in the room temperature ionic liquid (RTIL) [N8,2,2,2][NTf2]. Significantly enhanced currents for oxygen were observed, ranging from 9 to 16 times the current of the unmodified MATFE. The highest sensitivity was obtained using a two-step deposition with a total time of 420 s, and both steps containing Pb(OAc)2. This work shows that commercially-available microelectrodes can be favorably modified to give significantly enhanced analytical performances.

Effect of Pretreatment of Synthetic and Natural Carbons as Starting Materials for Carbon Nanotubes

2005 ◽  
Vol 23 ◽  
pp. 285-288 ◽  
Author(s):  
N. Buang ◽  
M. Aziz ◽  
S. Sanip ◽  
J.C. Tee ◽  
Z.H.Z Abidin ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Energy Storage And Conversion ◽  
Thermal Treatments ◽  
Active Materials ◽  
And Chemical Properties

Carbon are well known as active materials for energy storage and conversion. They are preferred because carbon materials have high electrical conductivity, low cost, high surface area, porosity, formability and possess good chemical and electrochemical resistivity. The most recently discovered novel carbon material is the carbon nanotubes, having unique geometrical structure and stable mechanical and chemical properties. The starting materials for carbon nanotubes production widely used are high purity graphite. Thus, two types of carbons were studied and thermal treatments were conducted at temperatures ranging from 600 – 800 °C for several hours. The effect of the pretreatment upon their morphology and surface area were looked into. It was found that significant changes occurred for the natural carbons while the synthetic carbons showed little or no changes at the particular temperature range. The thermal treatment has resulted in the exposure of fresh edge planes and microparticles as well as changes in the specific surface area and enhances their adsorption properties.

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