The prediction of mineral solubilities in natural waters: The Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system to high ionic strengths at 25°C

A semitheoretical approach for the ionization constant of water, KW, is used to fit the available experimental data over wide ranges of density and temperature. Statistical thermodynamics is employed to formulate a number of contributions to the standard state chemical potential of the ionic hydration process. A sorption model is developed for calculating the inner-shell term, which accounts for the ion–water interactions in the immediate ion vicinity. A new analytical expression is derived using the Bragg–Williams approximation that reproduces the dependence of a mean ion solvation number on the solvent chemical potential. The proposed model was found to be correct at the zero-density limit. The final formulation has a simple analytical form, includes seven adjustable parameters, and provides good fitting of the collected KW data, within experimental uncertainties, for a temperature range of 0–800 °C and densities of 0–1.2 g cm−3.

The Ionization Constant of Water over Wide Ranges of Temperature and Density

Electronic semiconducting oxides as pH sensors

Diabetes mellitus: biosensors for research and management.

We have developed a novel flexible pH sensor based on a polymeric substrate by low-cost sol–gel fabrication process of iridium oxide (IrOx) sensing film. A pair of miniature IrOx/AgCl electrodes on a flexible substrate generated electrical potentials in solutions by electrochemical mechanisms responding to their pH levels. Our flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response in sensitivity repeatedly and reversibly between −51.1 mV/pH and −51.7 mV/pH in the pH range between 1.5 and 12 at 25 °C. The fabrication processes including sol–gel deposition, thermal oxidation, and AgCl electro-plating on polymeric substrates were reported. The performance and characterization of the flexible pH sensors in sensitivity, response time, stability, reversibility, repeatability and selectivity were also discussed. Our IrOx pH electrodes on a deformable substrate demonstrated their sensing capability while they were conformed to a curved surface inside a limited space with distinct responding potentials at various pH levels similar to the traditional glass-rod pH electrodes.

A flexible pH sensor based on the iridium oxide sensing film

EMF measurements of cells employing metal—metal oxide electrodes in aqueous chloride and sulphate electrolytes at temperatures between 25–250°C

Stoichiometric activity coefficients of sulphuric acid and the standard potentials of the lead dioxide/lead sulphate and mercury/mercurous sulphate electrodes at 25°C

Dissociation constant of the bisulphate ion at 25°C

Determination of the ionization constant of water between 100 to 200°C by emf measurements, with some derived thermodynamic quantities

The permeability of gases through PTFE and other membranes at 25°C

J.V. Dobson

Papers

EMF measurements of cells employing metal—metal oxide electrodes in aqueous chloride and sulphate electrolytes at temperatures between 25–250°C

Stoichiometric activity coefficients of sulphuric acid and the standard potentials of the lead dioxide/lead sulphate and mercury/mercurous sulphate electrodes at 25°C

Dissociation constant of the bisulphate ion at 25°C

Determination of the ionization constant of water between 100 to 200°C by emf measurements, with some derived thermodynamic quantities

The permeability of gases through PTFE and other membranes at 25°C