CALCULATION OF ION EXCHANGE COLUMN FOR PURIFYING OF LITHIUM HYDROXIDE SOLUTION FROM CHLORINE ANIONS

In the article possibility of water solution LiOH tertiary treatment from chlorine anions after electrolysis is viewed. Analyzing the existing purification methods, it is proposed to use the purification of lithium hydroxide in an ion exchange column. A mathematical model and a computational algorithm for ion exchange column having stationary and moving anionite layers AВ-17-08 in ОН-form are given. Relationships of the main parameters such as working cycle period, usage ratio of ionite exchange volume and specific ratio of solution being purified per 1 kg ionite for standard column have been received. The curves of the chlorine anions density in ionite depending on its layer height in the solution being purified in the middle and at the end of the working cycle period are given. In the article recommendations on prevention of ionite granules abrasion during the operation in ion exchange columns are given.

Optimized Chromatographic Determination of Naphazoline and Chlorpheniramine in Eye/Nose Drops Using Cation-exchange Column

A simple and efficient liquid chromatographic method has been developed and validated for the simultaneous determination of naphazoline and chlorpheniramine in eye/nose drops, in presence of naphazoline degradation product and naphthalene acetic acid (NAPD). The separation was achieved within 6.0 min, employing a mixture of 53.5% v/v water-acetonitrile containing 78.70 mM/L sodium dihydrogen orthophosphate adjusted to pH 5.30 as isocratic mobile phase, pumped at 1.0 mL/min through a strong cation-exchange column (10 μm particle size), the analytes were monitored at 230 nm. Statistical experimental designs and graphic representations (response surface methodology) were used for optimizing the chromatographic separation. The linearity plots were linear over concentration range up to 125% of the analytes nominal concentrations (100%) with regression coefficients (r) > 0.99, method’s accuracy (RSD < 2.0%), repeatability and intermediate precision (RSD < 2.0%) were verified. System suitability parameters were also within the acceptable range. The validated method was successfully employed for the routine analysis of eye/nose drops.

Calculation of optimal flow of ionite during water treatment in the column of continuous action

In the article an algorithm for calculating the continuous ion exchange column is proposed. By analogy with the calculation of the optimal phlegm number of the rectification column this algorithm takes into consideration depreciation charges for capital costs associated with the size of the column and working capital associated with the consumption of ionite and its regeneration. This algorithm can be used to calculate depreciation charges for capital costs related to column sizes and working capital regarded to ionite consumption and regeneration. Examples of ionite consumption calculation at typical and proposed algorithms of calculation and technological and geometric parameters used in column of water purification from sodium cations are given. Thus, in a typical calculation, when the water being purified from sodium cations moves in the ideal displacement mode and the excess of ionite is 1% of its minimum consumption. The optimal ionite consumption corresponding to the minimum of capital costs and working capital, which requires an increase in the ionite consumption by 5.6% of its minimum consumption. In this case the cost of ion exchange increases by 4.5%. It confirms the recommendations for industrial operation and design of ion exchange columns and increases the minimum ionite consumption by 1÷10%. The continuous ion exchange column was calculated including the longitudinal diffusion. Necessity of the further increase of the ionite consumption with regard to the longitudinal diffusion is shown. In the article an example of the ion exchange process calculation in comparison with the typical one, when the displacement mode for the treated water is ideal, is given. Similar equations for the dependences of the concentration of extracted ions in the purified solution and ionite granules are proposed if the equilibrium dependence is described by a linear equation. The working line is dependent on the concentration of the extracted ions in an ionite and on their concentration in the purified water, first, because of a jump in concentration at the inlet and a concave shape of the working line (the latter is usually a straight one in case of the mass-transfer processes) reduces the local and average driving forces of mass-transfer process significantly. It leads to increasing of the moving layer height of the ion exchanger in the column 2 times, and can lead to crossing the line of equilibrium by reducing the concentration jump at the entrance. Consequently, it is necessary to increase ionite consumption by more than 18% compared to its minimum consumption.

Improved ion-exchange column chromatography for Cu purification from high-Na matrices and isotopic analysis by MC-ICPMS

Measurements of Cu isotopes from low concentration and high salinity matrices require high recovery and purity prior to measurement. A new automated two-stage chromatographic procedure yields highly pure Cu separations, low procedure blanks and much-improved reproducibility.