Ion exchange technology, principle and application scope
Ion exchange technology of ion exchange refers to the water by ion exchange column, the cation and the anion in the water in the water,
HCO - plasma)
With the Yang resin exchange column of H + ions and Yin OH - ion exchange resin, so as to achieve the purpose of desalination.
Ion exchange resin is a kind of insoluble polymers with functional groups, the structure of the ion exchange resin by polymer scaffold, ion exchange group and holes of three parts.
Its on the exchange of material adsorption, ion exchange, and achieve separation of the material, the displacement, purification, concentration, and concentration effect.
Ion exchange resin is the most precious is the nature of the ion exchange reaction reversibility, resin after application failure, acid, alkali or other available regenerant for regeneration, to restore its exchange capacity, repeated use of ion exchange resin in the long-term.
The classification of the ion exchange resin ion exchange resin can be divided into styrene type according to the types of the matrix resin and acrylic resin.
Resin in the chemical reactive species determines the main properties of the resin and categories.
First divided into two kinds of cationic resin and anion resin, they respectively with the solution of cationic and anionic ion exchange.
Cation resin is divided into two categories, strong acid and weak acid, anion resin is divided into two categories, strong alkaline and the weak alkaline (
Or separated in strong acid and strong alkali in class)
Ion exchange operation principle of the actual chemical desalination process, ion exchange reaction is conducted on ion exchanger, referred to as the 'post operation.
When water flow through ion exchange layer, after a period of time, the resin can be divided into three layers, the failure of the upper resin as 'failure' layer, middle is exchanged for 'exchange layer', lower level has not been exchanged for 'protection'.
With the extension of switch operation time, the failure layer increases gradually, declining work layer, when work layer down to cover limit, began to appear ion leakage, until the work layer of complete failure, ion exchange need to regenerate.
In the influencing factors of ion exchange work 1.
The water flow rate, the greater the working layer is thick.
High velocity, the water contact time is short, with the resin layer to keep the ion in the water to a certain degree, must be finished in a thick layer of work.
In general, the flow velocity under 60 m/h, water flow in the laminar flow state, for a little effects on the working exchange capacity of the resin, but more than the velocity will cause obvious thickening work layer, reduced working exchange capacity.
At present, the fixed bed level chemistry in addition to salt making machine operating velocity generally selected as the 10 -
30 m/h, top 40 m/h.
The choice of operating velocity and inlet water quality and running cycle and resin exchange capacity.
The thicker the resin particles, the greater the working layer.
The higher the ion concentration in water, the thicker the work layer.
Ion, the more the longer reaction time exchange, exchange layer is thick.
Related to the exchanger gap and water temperature.
Generally speaking, temperature rise, can reduce resin particles web of film thickness, favorable exchange reaction, but the water temperature rise, resin adsorption capacity decreases, even affecting the service life of resins, 20 - normally suggest water temperature
To remove silicon, the best water temperature 12 ℃)
Some other factors.
In thermal power plants (
Water and air quality standards)
, clear stipulation: conductivity is not greater than 5 us - level in addition to the brine
Is not higher than 100 cm, Sio2 content standard of ug/L.
Ion exchange technology in addition to the application scope of salt water, soften water, hydrometallurgy, separation and purification of precious metals medicine applications such as vitamins, terramycin, drink syrup decolorization, and nuclear power industry for nuclear grade resin absorption of radioactive element, etc.
Food and beverage, pharmaceutical, surface treatment, industrial pure water and pure water making machine.
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