The transport properties of sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) in aqueous 2-butoxyethanol (mass fractions: 0.20, 0.40, and 0.60) mixtures were examined using electrical conductivity measurements at 298.15, 303.15, 308.15, and 313.15 K. The experimental conductance data were analyzed using the Fuoss conductance-concentration equation (1978) to evaluate ion association parameters and to gain insights into the ion-solvent and ion-ion interactions within the mixed solvent systems. The estimates of the individual ionic contributions to the limiting molar conductance were also made in this analysis. The calculated values of ion association parameters suggest a weak electrostatic ion solvent interaction for these two salts in aqueous 2-butoxyethanol mixture. Moreover, the electrolytes were found to exist predominantly as free ions across all solvent compositions and within the entire temperature range investigated in this study. The influence of temperature and solvent composition on the association constants and single-ion conductivities of the electrolytes was systematically examined and discussed. The Walden products of the ions exhibited significant deviations with changes in temperature and solvent composition.
Enzyme immobilization is one of the key factors in constructing high-performance bio-devices. Herein, a honeycomb-like three-dimensional nanoporous gold (3DHNPG) was electrodeposited by an one-step dynamic gas bubble template method for enzyme immobilization and enzyme-electrode fabrication. A CS/GOx/3DHNPG/Au electrode was prepared simply by cast-coating glucose oxidase (GOx) and chitosan (CS) successively on the 3DHNPG modified Au electrode and air-dried. The thus-prepared CS/GOx/3DHNPG/Au electrode responded linearly to glucose from 0.01 to 4.4 mM with a sensitivity of 166 μA mM−1 cm−2 and a limit of detection of 1.2 μM (first-generation biosensing mode). Due to the special porous structure of 3DHNPG with large specific surface area, as well as high catalytic activity for H2O2 oxidation, the sensitivity of CS/GOx/3DHNPG/Au electrode for glucose sensing is greatly enhanced, which is larger than those of CS/GOx/Auplate/Au electrode, CS/GOx/Au electrode, and most reported GOx-based enzyme electrodes. This 3DHNPG-based enzyme electrode also worked well in the second-generation biosensing mode and as a bioanode in a monopolar biofuel cell. The 3DHNPG with great convenience in synthesis, outstanding biocompatibility and electron-conductibility may be an excellent matrix choice to immobilize biomolecules for constructing high-performance biodevices with promising applications.
Equilibrium alloys of the Ag–Sn–S system in the Ag2S–SnS2–S composition range are studied by electromotive forces (EMF) measurements of concentration cells relative to a silver electrode cell with Ag4RbI5 solid electrolyte over the 300–390 K temperature range. A linear equation for the EMF temperature dependence is obtained, from which the silver partial molar functions in the alloys are calculated. Based on the solid-phase equilibria diagram of the Ag–Sn–S system, a virtual potential-determining reaction is established. This reaction is used in the calculating of the standard thermodynamic formation functions and standard entropy of the Ag8SnS6 low-temperature modification. By combining the obtained data with the phase transition thermodynamic functions of the compound, the corresponding functions for its high-temperature modification are calculated.
The ionic pairing of 1-butyl-3-methylimidazolium tetrachloroferrate [Bmim] [FeCl4] magnetic ionic liquid in two plasticizers ethylene carbonate (EC), propylene carbonate (PC) separately and combination of (EC–PC) has been studied by ATR Infrared spectroscopy. Spectra were taken in the IR range 600 to 4000 cm–1. For experimental analysis plasticizer concentration range of 0.5 to 2.0 mol was used. The interaction of [Bmim] with these plasticizers (EC, PC and EC + PC) modifies the Hydrogen bonding. The complex and broad bands in FTIR after interactions is an indication of ionic pairing.
The transport properties of sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) in aqueous 2-butoxyethanol (mass fractions: 0.20, 0.40, and 0.60) mixtures were examined using electrical conductivity measurements at 298.15, 303.15, 308.15, and 313.15 K. The experimental conductance data were analyzed using the Fuoss conductance–concentration equation (1978) to evaluate ion association parameters and to gain insights into the ion–solvent and ion–ion interactions within the mixed solvent systems. The estimates of the individual ionic contributions to the limiting molar conductance were also made in this analysis. The calculated values of ion association parameters suggest a weak electrostatic ion solvent interaction for these two salts in aqueous 2-butoxyethanol mixture. Moreover, the electrolytes were found to exist predominantly as free ions across all solvent compositions and within the entire temperature range investigated in this study. The influence of temperature and solvent composition on the association constants and single-ion conductivities of the electrolytes was systematically examined and discussed. The Walden products of the ions exhibited significant deviations with changes in temperature and solvent composition.
