Conduction Mechanism and Dielectric Properties in Polyaniline/Titanium Dioxide Composites

The conductivity and dielectric properties of polyaniline (PANI) and PANI/TiO2 composites have been studied over a temperature range (313-393 K) and frequency range (25 Hz- 50 MHz). The nature of temperature and frequency-dependent conductivity can be explained by Jonscher’s universal power law and used to find the related parameters such as frequency exponent (s), dc conductivity (σdc), and crossover frequency (ωH). Besides, the frequency exponent analysis through a distinct model suggests that the conduction occurred through small polaron tunnelling in all compositions and at different temperatures. On the other hand, the enthalpy of migration (Hm), dissociation enthalpy of cation from its indigenous location alongside a compensating center (Hf), and the activation energy were also calculated using the Arrhenius relation. The temperature-dependent dc conductivity was examined in the framework of the theoretical model; Mott’s variable range hopping model (VRH) and experimental results were in good agreement with the 3-dimensional VRH model. As a function of temperature, dielectric constants (ε’ and ε”) increase while decreasing with an increasing dopant. Being such a high dielectric constant value, these composites can be used as frequency converters, modulators, and dielectric amplifiers

IPA-Open access -Distributed under Creative Commons Attribution License 2.0 Strategies for Management of Metal Contaminated Soil

ABSTRACT Heavy metals are inadvertently released during manufacture of various industrial products. They are serious pollutants due to their toxicity, persistence and bioaccumulation problems. Microorganisms have the potential to alter the reactivity and mobility of metals and thus facilitating the use of bioremediation as a form of treatment for metal contaminated soils. Utilizing microbes for bioremediation possesses various merits such as their natural occurrence, cheap production, easy availability and high selectivity in terms of removal and recovery of specific metals. This paper summarizes the general processes of bioremediation within the soil environment. The effect of environmental factors which governs the rate of biodegradation is addressed together with limitations and potential of ex situ and in situ bioremediation

Conduction Mechanism and Dielectric Properties in Polyaniline/Titanium Dioxide Composites

982-988The conductivity and dielectric properties of polyaniline (PANI) and PANI/TiO2 composites have been studied over a temperature range (313-393 K) and frequency range (25 Hz- 50 MHz). The nature of temperature and frequency-dependent conductivity can be explained by Jonscher’s universal power law and used to find the related parameters such as frequency exponent (s), dc conductivity (σdc), and crossover frequency (ωH). Besides, the frequency exponent analysis through a distinct model suggests that the conduction occurred through small polaron tunnelling in all compositions and at different temperatures. On the other hand, the enthalpy of migration (Hm), dissociation enthalpy of cation from its indigenous location alongside a compensating center (Hf), and the activation energy were also calculated using the Arrhenius relation. The temperature-dependent dc conductivity was examined in the framework of the theoretical model; Mott’s variable range hopping model (VRH) and experimental results were in good agreement with the 3-dimensional VRH model. As a function of temperature, dielectric constants (ε’ and ε”) increase while decreasing with an increasing dopant. Being such a high dielectric constant value, these composites can be used as frequency converters, modulators, and dielectric amplifiers

Polyaniline Chromium Nitrate Composites: Influence of Chromium Nitrate on Conductivity and Thermal Stability of Polyaniline

198-205Thermal stability and electrical conductivity are the key to the technological feasibility and sustainability of conducting polymers (CPs) and their composites in real-time applications. Notably, the impact of filler loading on above mentioned parameters of CPs needs to be examined and addressed with facile and easily accessible techniques. In the present study, Polyaniline (PANI) /chromium nitrate composites have been prepared via in situ polymerization of aniline through the chemical oxidative polymerization route. After that, the conductivity and thermal stability of PANI have been investigated at different weight percentage loadings of chromium nitrate viz 5, 10, 20, and 40 % in the composite materials. The morphological and structural analysis of the pristine and composite samples were executed with Scanning electron microscopy (SEM), Fourier transforms infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) techniques. Thermal analysis of proposed composites is carried out using the thermogravimetric analysis (TGA) method to evaluate various kinetic parameters. The TGA thermogram and different calculated parameters revealed that the composites were more thermally stable than pristine PANI and that the composite having 20 wt % of chromium nitrate is thermally the most stable. The DC electrical conductivity data shows that PANI loaded with 20% chromium nitrate has the highest conductivity. This increment in conductivity and thermal stability of the composites opens the path for many applications, such as sensors and electronics