ABSTRACT Based on the property of laminar flow through a capillary tube, the axial dispersion characteristics of the injected sample solute were investigated and an application to the measurement of molecular diffusion coefficient of both colored and colorless inorganic chemicals in liquids was developed. Two types of the experimental apparatus have been presented to measure dispersion width of breakthrough curves for the injected solutes. Both apparatus were made mainly of a syringe pump, head-space sample injection port, transparent poly(tetrafluoroethylene) tube and detection unit. One of them could obtain an ideal laminar flow and apply to determine directly the coefficients for colored samples such as iodide, permanganate and dichromate. The another was consisted of a refratometric detector for colorless ones. The coefficient of the inorganic chemical sample was calculated from the baseline-to-baseline width of the residence time distribution in each breakthrough curve. The experimental results obtained had a good agreement with the theoretical values. This research presented a rapid and useful method with precision and reproducibility for the molecular diffusivity measurement against every inorganic chemical sample dissolved in various liquids.
Buy this Article
|