Presence Of Electric Potential Research Articles

Hybrid Optoelectrochemical Sensor for Superselective Detection of 2,4,6-Trinitrotoluene Based on Electrochemical Reduced Meisenheimer Complex

2,4,6-Trinitrotoluene (TNT) is known as one of the most used explosives, and its detection is significant in public security, human health, and environmental protection. The fabrication of absorbance based optical sensors for TNT is a serious challenge due to poor selectivity and sensitivity. We reported the design and fabrication of a superselective hybrid optoelectrochemical sensor based on the electrochemical reduction of Meisenheimer complex in a deep eutectic solvent (DES) modified with n-butylamine (nBA) for determination of TNT. The hybrid optoelectrochemical sensor (HOPES) that placed in DES modified with nBA and also an optical sensor (OPS) were fabricated. The electrochemical reduction of Meisenheimer complex occurred at HOPES when the potential was applied and consequently the sensing performance (sensitivity and selectivity) was dramatically enhanced compared to OPS. The both OPS and HOPES responded linearly to TNT with detection limits of 310 and 8 nmol L-1, respectively. The selectivity observed for the HOPES toward TNT compared to the other interferences was enhanced by a factor of 103-104, thus we can use the term "superselectivity" for HOPES. The mechanism of HOPES response was proved by optoelectrochemical and electrochemical impedance spectroscopy (EIS) techniques. The field emission scanning electron microscope (FESEM) was employed for the characterization of electrodeposited Meisenheimer layer. Finally, we presented a proposed model for the sensing mechanism of OPS and HOPES based on TNT complexation in the absence and presence of electric potential, respectively.

Decolorization of synthetic dye wastewater using packed bed electro-adsorption column

The present study reports the electro-adsorption of Methylene blue (MB) dye from synthetic wastewater onto activated carbon in a packed bed electro-adsorption column and the break through data was analyzed for dye adsorption. The influences of bed height, flow rate and initial dye concentration with and without the presence of electrical potential on packed bed adsorption have been investigated and the possibility of regeneration of column was studied. The parameters such as bed capacity, mass transfer zone, bed utilization and adsorbent usage were evaluated from the break through curves. The columns characteristic design parameters have been evaluated using the adsorption models such as Bed Depth Service Time (BDST), Adam-boharts, Thomas and Yoon-Nelson models. The model parameters have been derived using origin software. Out of four adsorption models, Thomas and Yoon-Nelson models were found to be ideal to analyze the column performance with R2 ≥ 0.80. From the results, it is observed that electro-adsorption is more efficient than adsorption as the adsorption capacity is 3.18 folds higher and the amount of adsorbent required was much lesser for electro-adsorption. Also the saturation capacity is 0.17 mg/g for electro-adsorption whereas it is 0.069 mg/g for conventional adsorption at optimized condition, which confirms the stability of electro-adsorption column. It has been observed that modifications in electrode played a major role in dye waste water treatment processes.

Electro-osmotic flow of power-law fluid and heat transfer in a micro-channel with effects of Joule heating and thermal radiation

A mathematical model has been developed for studying the electro-osmotic flow and heat transfer of bio-fluids in a micro-channel in the presence of Joule heating effects. The flow of bio-fluid is governed by the non-Newtonian power-law fluid model. The effects of thermal radiation and velocity slip condition have been examined in the case of hydrophobic channel. The Poisson–Boltzmann equation governing the electrical double layer field and a body force generated by the applied electric potential field are taken into consideration. The results presented here pertain to the case where the height of the channel is much greater than the thickness of electrical double layer comprising the Stern and diffuse layers. The expressions for flow characteristics such as velocity, temperature, shear stress and Nusselt number have been derived analytically under the purview of the present model. The results estimated on the basis of the data available in the existing scientific literatures are presented graphically. The effects of thermal radiation have an important bearing on the therapeutic procedure of hyperthermia, particularly in understanding the heat transfer in micro-channel in the presence of electric potential. The dimensionless Joule heating parameter has a reducing impact on Nusselt number for both pseudo-plastic and dilatant fluids, nevertheless its impact on Nusselt number is more pronounced for dilatant fluid. Furthermore, the effect of viscous dissipation has a significant role in controlling heat transfer and should not be neglected.

Visualization of Electrochemical Reactions in Battery Materials with X-ray Microscopy

In this talk, I will discuss examples of the visualization of phase transformations using a variety of modes within the general family of X-ray microscopy, tailored to suit the scales and phenomena to be probed, but focusing on single particles. Because thermodynamic pathways can be controlled by the presence of electrical potential, the harvesting of a sample from a cycled battery, while providing a useful preliminary insight, can lead to misleading results due to the relaxation of components into a different state that is more stable under open circuit conditions. Therefore, measurements performed during the electrochemical reaction will be leveraged in this discussion. The mechanisms of transformation will be related to their impact on material and architecture properties.

Two‐phase electromembrane extraction followed by gas chromatography‐mass spectrometry analysis

A two-phase electromembrane extraction (EME) was developed and directly coupled with gas chromatography mass spectrometry (GC-MS) analysis. The proposed method was successfully applied to the simultaneous determination of imipramine, desipramine, citalopram and sertraline. The model compounds were extracted from neutral aqueous sample solutions into the organic phase filled in the lumen of the hollow fiber. This method was accomplished with 1-heptanol as organic phase, by means of 60 V applied voltage and with the extraction time of 15 min. Experiments reported recoveries in the range of 69-87% from 1.2 mL neutral sample solution. The compounds were quantified by GC-MS instrument, with acceptable linearity ranging from 1 to 500 ng mL(-1) (R(2) in the range of 0.989 to 0.998), and repeatability (RSD) ranging between 7.5 and 11.5% (n = 5). The estimated detection limits (S/N ratio of 3:1) were less than 0.25 ng mL(-1). This novel approach based on two-phase EME brought advantages such as simplicity, low-costing, low detection limit and fast extraction with a total analysis time less than 25 min. These experimental findings were highly interesting and demonstrated the possibility of solving ionic species in the organic phase at the presence of electrical potential.

Solution of Time-Independent Schrodinger Equation for a Two-Dimensional Quantum Harmonic Oscillator Using He's Homotopy Perturbation Method

In this paper, time-independent Schr\{o}dinger equation for a charged particle, in the presence of electric potential and vector potential, has been solved using He's Homotopy Perturbation Method (HPM). HPM is one of the newest analytical methods to solve linear and nonlinear differential equations. In contrast to the traditional perturbation methods, the Homotopy method does not require a small parameter in the equation. In this method, according to the homotopy technique, a Homotopy with an embedding parameter $\delta \in \lbrack 0,1]$ is constructed, and the embedding parameter is considered as a small parameter. Using cylindrical coordinates, it has been found that the z-equation of the charged particle is a one-dimensional harmonic oscillator and the r equation is actually a two-dimensional harmonic oscillator. The obtained results show the evidence of simplicity, usefulness, and effectiveness of the HPM for obtaining approximate analytical solutions for the time-independent Schr\{o}dinger equation for a charged particle in parallel electric and magnetic fields.

Environmental conditions influence for real-time hologram formation on dichromated polyvinyl alcohol NiCl2·6H2O doped films

The real-time holographic gratings recording are studied by the presence of a metallic salt. The experimental process refers to analysis of diffraction efficiency by the influence of humidity in the coating solution on holograms formation in presence of electrical potential. The diffraction efficiency is measured as a function of the exposure energy until reach the saturation. The influence of the hologram parameters to get the diffraction efficiency is studied at room conditions.

Electrically enhanced ethanol fermentation by Clostridium thermocellum and Saccharomyces cerevisiae.

Ethanol production by Clostridium thermocellum ATCC 35609 and Saccharomyces cerevisiae ATCC 26603 was improved in an electrochemical bioreactor system. It was increased by 61% with Cl. thermocellum and 12% with S. cerevisiae in the presence of -1.5 V of electric potential. These increases were attributed to high production rates due to regeneration and availability of increased reduced equivalents in the presence of electric potential. The electric current caused considerable shift in the metabolite concentrations on a molar basis in Cl. thermocellum fermentation but less in S. cerevisiae fermentation. Increasing electric potential in Cl. thermocellum fermentation resulted in less acetate and more lactate production. Acetate production was also reduced with increased electric potential in S. cerevisiae fermentation. The high electric potential of -5 V adversely affected the Cl. thermocellum fermentation, but not the S. cerevisiae fermentation even at a high electric potential of -10 V.

Evaluation of an electrochemical bioreactor system in the biotransformation of 6-bromo-2-tetralone to 6-bromo-2-tetralol.

Biotransformation of 6-bromo-2-tetralone (Br-beta-tetralone) to 6-bromo-2-tetralol (Br-beta-tetralol) by yeast cells of Trichosporon capitatum (ATCC 74312) and its partially purified Br-beta-tetralone reductase was evaluated in an electrochemical bioreactor. The biotransformation rates and final product formation were significantly affected by substrate concentration, biomass and electric potential. At 2 g/l of substrate, the initial reaction rate and final product were increased by 35% and 15%, respectively, with -1.5 V of electric potential compared to without electric potential. Additional substrate (2 g/l) provided by pulse feeding to the reaction mixture at different intervals resulted in 2.1 g/l Br-beta-tetralol compared to a total of 1.2 g/l without feeding. However, the increased production was not proportionate to the amount of additionally fed substrate. Increased substrate availability by the addition of 5% (v/v) ethanol resulted in the highest reaction rate and product formation, but addition of ethanol at a concentration higher than 5% decreased the reaction rate. At low biomass, the initial reaction rates were enhanced significantly when electric potential was high, but a higher biomass was necessary to obtain a similar reaction rate when electric potential was reduced. The highest initial reaction rate (59.2 mg/l per min) was achieved with a two-fold biomass concentration of 15.6 g of dry cell weight/l, substrate at 4 g/l and electric potential at -6 V. The conversion of Br-beta-tetralone to Br-beta-tetralol with partially purified Br-beta-tetralone reductase was slow in the presence of electric potential.