scholarly journals Modified Polyaniline Nanofibres for Ascorbic Acid Detection

2011 ◽  
Vol 1312 ◽  
Author(s):  
Larisa Florea ◽  
Emer Lahiff ◽  
Dermot Diamond
Keyword(s):  
Ascorbic Acid ◽  
Carboxylic Acid ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Redox States ◽  
Sensing Applications ◽  
Ph Range ◽  
Surface Modified ◽  
Ascorbic Acid Detection

ABSTRACTPolyaniline nanofibres (PAni) can be surface modified to improve electroactivity over a broader pH range. The technique we describe here can be used to attach carboxylic acid terminated substituents. Modified nanofibres maintain their high surface area, and ability to switch between different redox states. These properties make the material suitable for sensing applications. Unlike unmodified PAni, the functionalised material is self-doping and hence more stable in higher pH solutions. Here we demonstrate how modified PAni fibres can be used for the detection of ascorbic acid.

Amine Modified Magnetic Diatomite Particles as an Effcicent Adsorbent for Pecticide Removal

2021 ◽  
Author(s):  
İhsan Alacabey
Keyword(s):  
Surface Area ◽  
Emerging Contaminants ◽  
High Surface ◽  
High Surface Area ◽  
Scan Ning Electron Microscopy ◽  
Promising Alternative ◽  
Pesticide Removal ◽  
Spin Resonance ◽  
Ft Ir ◽  
Surface Modified

Pesticides are one of the most critical emerging contaminants which are highly toxic for the environment and have potential risk to human health. In this study, surface-modified magnetic diatomite particles (m-DE-APTES) have been suc-cessfully synthesized and used as a sorbent for the removal of endosulfan from an aqueous solution. Magnetic diatomite particles with surface modification were characterized by Fourier transform-infrared spectroscopy (FT-IR), scan-ning electron microscopy (SEM), energy dispersive X-ray (EDX), electron spin resonance (ESR), and surface area measurements. Characterization results sug-gest that magnetic diatomite has a high surface area and porous structure. In addition, m-DE-APTES has higher adsorption capacity (97.2 mg/g) for en-dosulfan pesticide than unmodified diatomite particles (DE) (16.6 mg/g). The adsorption data fit the Langmuir model (R2=0.9905), and the adsorption process took place spontaneously with the values of ΔGo as -2.576. In conclusion, the surface-modified diatomite particles are promising alternative adsorbents for pesticide removal from aqueous solutions.

Fabrication of Ag/ZnO Nanoparticles Using Ascorbic Acid as Reducing Agent

2016 ◽  
Vol 1133 ◽  
pp. 462-466 ◽  
Author(s):  
Jeyashelly Andas ◽  
Nor Wahida Subri
Keyword(s):  
Ascorbic Acid ◽  
Surface Area ◽  
Zno Nanoparticles ◽  
High Surface ◽  
High Surface Area ◽  
Absorption Spectrometry ◽  
Average Diameter ◽  
Reducing Agent ◽  
Bet Surface Area ◽  
Simple Method

High surface area Ag/ZnO with an average diameter of 13.95 nm was successfully synthesized through a facile route, using ascorbic acid and silica rice husk as reducing agent and amorphous support respectively. This nanomaterial was characterized by transmission electron microscopy, N2 adsorption-desorption, atomic absorption spectrometry and particle size analyzer. This simple method resulted in the production of almost spherical Ag/ZnO nanoparticles with high BET surface area and large pore volume of 341.46 m2g-1 and 0.59 cm3g-1 respectively. This preliminary study revealed the successful inclusion of metal cations into the silica framework without damaging the mesoporosity nature of silica.

scholarly journals Potentiometric Biosensing of Ascorbic Acid, Uric Acid, and Cysteine in Microliter Volumes Using Miniaturized Nanoporous Gold Electrodes

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Christopher J. Freeman ◽  
Borkat Ullah ◽  
Md. Shafiul Islam ◽  
Maryanne M. Collinson
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Nanoporous Gold ◽  
Redox Potentials ◽  
Biologically Relevant ◽  
Redox Sensing ◽  
Redox Molecules

Potentiometric redox sensing is a relatively inexpensive and passive approach to evaluate the overall redox state of complex biological and environmental solutions. The ability to make such measurements in ultra-small volumes using high surface area, nanoporous electrodes is of particular importance as such electrodes can improve the rates of electron transfer and reduce the effects of biofouling on the electrochemical signal. This work focuses on the fabrication of miniaturized nanoporous gold (NPG) electrodes with a high surface area and a small footprint for the potentiometric redox sensing of three biologically relevant redox molecules (ascorbic acid, uric acid, and cysteine) in microliter volumes. The NPG electrodes were inexpensively made by attaching a nanoporous gold leaf prepared by dealloying 12K gold in nitric acid to a modified glass capillary (1.5 mm id) and establishing an electrode connection with copper tape. The surface area of the electrodes was ~1.5 cm2, providing a roughness factor of ~16 relative to the geometric area of 0.09 cm2. Scanning electron microscopy confirmed the nanoporous framework. A linear dependence between the open-circuit potential (OCP) and the logarithm of concentration (e.g., Nernstian-like behavior) was obtained for all three redox molecules in 100 μL buffered solutions. As a first step towards understanding a real system, the response associated with changing the concentration of one redox species in the presence of the other two was examined. These results show that at NPG, the redox potential of a solution containing biologically relevant concentrations of ascorbic acid, uric acid, and cysteine is strongly influenced by ascorbic acid. Such information is important for the measurement of redox potentials in complex biological solutions.

Amine Modified Magnetic Diatomite Particles as an Effcicent Adsorbent for Pecticide Removal

2021 ◽  
Author(s):  
İhsan Alacabey
Keyword(s):  
Surface Area ◽  
Emerging Contaminants ◽  
High Surface ◽  
High Surface Area ◽  
Scan Ning Electron Microscopy ◽  
Promising Alternative ◽  
Pesticide Removal ◽  
Spin Resonance ◽  
Ft Ir ◽  
Surface Modified

Pesticides are one of the most critical emerging contaminants which are highly toxic for the environment and have potential risk to human health. In this study, surface-modified magnetic diatomite particles (m-DE-APTES) have been suc-cessfully synthesized and used as a sorbent for the removal of endosulfan from an aqueous solution. Magnetic diatomite particles with surface modification were characterized by Fourier transform-infrared spectroscopy (FT-IR), scan-ning electron microscopy (SEM), energy dispersive X-ray (EDX), electron spin resonance (ESR), and surface area measurements. Characterization results sug-gest that magnetic diatomite has a high surface area and porous structure. In addition, m-DE-APTES has higher adsorption capacity (97.2 mg/g) for en-dosulfan pesticide than unmodified diatomite particles (DE) (16.6 mg/g). The adsorption data fit the Langmuir model (R2=0.9905), and the adsorption process took place spontaneously with the values of ΔGo as -2.576. In conclusion, the surface-modified diatomite particles are promising alternative adsorbents for pesticide removal from aqueous solutions.

scholarly journals Salt-Mediated Au-Cu Nanofoam and Au-Cu-Pd Porous Macrobeam Synthesis

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1701 ◽  
Author(s):  
Fred Burpo ◽  
Enoch Nagelli ◽  
Lauren Morris ◽  
Kamil Woronowicz ◽  
Alexander Mitropoulos
Keyword(s):  
Surface Area ◽  
Electrochemical Impedance ◽  
High Surface ◽  
Electronic Conductivity ◽  
High Surface Area ◽  
Three Dimensional ◽  
Synthesis Methods ◽  
X Ray ◽  
Sensing Applications ◽  
Metal Composition

Multi-metallic and alloy nanomaterials enable a broad range of catalytic applications with high surface area and tuning reaction specificity through the variation of metal composition. The ability to synthesize these materials as three-dimensional nanostructures enables control of surface area, pore size and mass transfer properties, electronic conductivity, and ultimately device integration. Au-Cu nanomaterials offer tunable optical and catalytic properties at reduced material cost. The synthesis methods for Au-Cu nanostructures, especially three-dimensional materials, has been limited. Here, we present Au-Cu nanofoams and Au-Cu-Pd macrobeams synthesized from salt precursors. Salt precursors formed from the precipitation of square planar ions resulted in short- and long-range ordered crystals that, when reduced in solution, form nanofoams or macrobeams that can be dried or pressed into freestanding monoliths or films. Metal composition was determined with X-ray diffraction and energy dispersive X-ray spectroscopy. Nitrogen gas adsorption indicated an Au-Cu nanofoam specific surface area of 19.4 m2/g. Specific capacitance determined with electrochemical impedance spectroscopy was 46.0 F/g and 52.5 F/g for Au-Cu nanofoams and Au-Cu-Pd macrobeams, respectively. The use of salt precursors is envisioned as a synthesis route to numerous metal and multi-metallic nanostructures for catalytic, energy storage, and sensing applications.

High surface area porous carbon for ultracapacitor application by pyrolysis of polystyrene containing pendant carboxylic acid groups prepared via click chemistry

2015 ◽  
Vol 4 ◽  
pp. 166-175 ◽  
Author(s):  
Shraddha Chhatre ◽  
Vanchiappan Aravindan ◽  
Dhanya Puthusseri ◽  
Abhik Banerjee ◽  
Srinivasan Madhavi ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Click Chemistry ◽  
Surface Area ◽  
Porous Carbon ◽  
High Surface ◽  
High Surface Area ◽  
Carboxylic Acid Groups

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

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