Preparation and characterization of novel potassium ion conducting nanocomposite polymer electrolytes based on PEMA

Potassium ion conducting nanocomposite polymer electrolytes was prepared by employing the solvent casting technique. Poly ethyl methacrylate (PEMA), potassium thiocyanate (KSCN) and nano-strontium titanate (SrTiO3) (<100 nm) was used as a polymer host, an electrolyte and a filler, respectively. The complex formation between PEMA, KSCN and SrTiO3 was confirmed through Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis, respectively. This system exhibited two ionic conductivity maxima, but the sample, PEMA/KSCN/4 wt% SrTiO3 delivered a maximum ionic conductivity of 3.07 × 10−5 Scm−1 at room temperature, which was 102 times greater than that of PEMA/KSCN system. Truckhan model was employed to determine the diffusion coefficient, mobility and mobile ion concentration of the system. The remarkable change in surface morphology of the sample was observed through Scanning Electron Microscopy (SEM) micrograph.

Phase Studies and Efficient Recovery of Inorganic Metal Salts from the Microemulsion System Using a Sugar-Based Non-Ionic Surfactant

In the present work, the phase behaviour of the microemulsion system formulated by using water, organic solvent, and a sugar-based non-ionic surfactant was investigated in detail. We have used a sugar-based non-ionic surfactant for formulation of microemulsion, as it is a greener alternative for the formulation of a microemulsion system, owing to the following aspects: a) better physicochemical properties as compared to that of the conventional non-ionic surfactants, b) non-toxicity, and c) biodegradability. The extraction of heavy metal ions from the metal complexes as well as the recovery efficiency of heavy metal ions using a microemulsion system has been investigated. The maximum absorbance values of metal ions, after recovery from the metal complexes, were measured. Moreover, the UV-Visible spectrophotometric studies revealed that the absorbance increases with an increase in metal ion concentration in the aqueous phase while its value decreases with an increase in the concentration of potassium thiocyanate in the aqueous phase after the extraction of the metal ions from the metal complexes. Furthermore, it has also been evaluated that 4.0 mol/L potassium thiocyanate is the optimum concentration required for efficient recovery of 0.05 mol/L cobalt ion as well as nickel ions. The recovery efficiency of cobalt ions was found to be 97%, whereas that of nickel ions was determined to be 94% respectively. In addition to being an environmentally friendly approach, the present work is an economically viable option too, as it deals with the studies related to the extraction and efficient recovery of metal ions.

Competitive Ligand Binding and Photosensitivity Studies of Iron(III)-thiocyanate in presence of Glutamate ion

Addition of a chelating ligand (glutamate ion) to [Fe(SCN)]2+ solution leads to change in the colour. On increasing the glutamate ion concentration in iron thiocyanate complex solution, the colour of [Fe(SCN)]2+ disappears with the emergence of a new peak at lower wavelength due to the formation of [Fe(Glu)]2+complex. The conductance of [Fe(SCN)]2+ complex ion in solution is high while on addition of different concentrations of glutamate ion to iron thiocyanate complex, their conductance value decreases due to formation of [Fe(Glu)]2+. Photosensitivity studies of a series of solutions prepared by the addition of glutamate ion of varying concentrations to ferric chloride-ammonium thiocyanate/potassium thiocyanate solution in the short UV region demonstrate the better stability of [Fe(Glu)]2+compared to [Fe(SCN)]2+ and the rate kinetics of decomposition has been reported.

Soluble tungsten compounds Determination in workplace air

Tungsten is a transition metal which occurs in the Earth’s crust as minerals which after being mined is extracted. There is no data on chronic effects of contact with tungsten, although fine tungsten powder is flammable and can cause mechanical irritation to skin and eyes. However, there are soluble tungsten compounds, which are classified as toxic, causing damage to the eyes, and being harmful to the aquatic environment. The aim of the study was to amend Standard No. PN-Z-04221-3 determination of soluble tungsten compounds in workplace air using spectrophotometric method with potassium thiocyanate. The amendment was performed because Standard No. PN-Z-04221-3 describes a method in which the quantification is 0.25 mg/m3, according to European Standard No. EN 482 the quantification of method must be in range of 0.1 – 2 mg/m3. The method is based on depositing soluble tungsten compounds on a cellulose esters filter and then dissolving them in water. Then tungsten is reduced with tin chloride, after reaction with potassium thiocyanate, tungsten becomes a complex. Tungsten complex should be extracted with isoamyl alcohol and then absorbance should be measured on a UV-Vis spectrophotometer. The tests were performed with the UV-Vis Heλios spectrophotometer by ThermoSpectronic model Beta. The validation requirements of European Standard No. EN 482 were met. With this method soluble tungsten compounds in air can be determined at concentration of 0.1 – 2 mg/m3. The limit of quantification (LOQ) is 1.875 ng. The overall accuracy of the method is 5.06% and its relative total uncertainty is 22.09%. The method for determining tungsten has been recorded in a form of an analytical procedure (see Appendix). This article discusses problems of occupational safety and health, which are covered by health sciences and environmental engineering.