Principle and function of EDI desalinated water
EDI equipment, as many people who have used it, know that it is a kind of equipment specially used for demineralization. There are no ionic components other than oxygen ions. Today, the editor will tell you about the principle and function of EDI desalination.
Why EDI is needed for desalting
Usually groundwater or tap water contains various substances, including some trace solid particles, colloids, metals, minerals, salts, compounds, etc. Most of the substances can be removed through the previous process of industrial circulating water treatment. The filter can remove the impurities visible to the naked eye. The first-stage and second-stage reverse osmosis can remove minerals, compounds and 99% of salts, and there are 1% of salts left. Because the ion diameter is too small, reverse osmosis cannot be removed. EDI equipment is required for desalination. These salts are usually dissolved salts of sodium, calcium, magnesium, chlorine, nitrate, silicon, etc.
The principle of EDI desalination
All salts are composed of negative and positive ions. The key technology of EDI equipment is ion exchange. When all substances are split into various cations and anions, various ions can be replaced.
The traditional ion exchange is to use ion exchange resin for exchange, but the hydroxide ions in the resin are limited. After all the hydroxide ions in the resin are exchanged, the resin can no longer be exchanged. At this time, it is necessary to add a chemical regenerant, so that the hydroxide ions are regenerated in the resin and exchanged again. However, this method requires a lot of manpower first. Every time it is necessary to check whether the resin needs to be added with a regenerant, the operation time is long, the exchange efficiency is low, and it is easy to produce secondary pollution. The ion exchange resin is placed in the EDI equipment, and the electrodialysis technology is used to separate the water molecule H2O into H+ and OH-, which can generate a steady stream of hydroxide ions for the resin to carry out uninterrupted ion exchange. High efficiency, low pollution and stable water quality. It is an ideal product for the preparation of industrial pure water.
The role of EDI in demineralized water
1. Preparation of ultrapure water in electronics, semiconductor, precision machinery and chip industries
2. Desalination and purification of sea water and brackish water
3. Preparation of ultrapure water in pharmaceutical industry
4. Water for fine chemicals and advanced disciplines
The function and efficacy of EDI desalination are related to the purity of the influent water. The higher the purity of the influent water, the better the EDI desalination effect, and the purer the deionized product water produced, otherwise the worse the water quality. Therefore, when the EDI equipment is in use, it must go through a primary or secondary reverse osmosis to purify and filter the water quality. finally achieve the effect of industrial use
