Water demineralization is an important stage in water preparation for industrial purposes

Water demineralization is an important stage in water preparation for industrial purposes

There are salts in water, the presence of which under special conditions makes water electrically and chemically active. This has a negative effect on the operation of manufactured products and the functionality of certain types of equipment. An important link in production technical processes is a special stage of water treatment - water demineralization.

The process by which all mineral substances are removed from water is called the process of water demineralization. There are four methods of water demineralization: deionization, reverse osmosis, distillation and electrodialysis.

Deionization is a process that uses the ion exchange method. During deionization, water is processed in two layers of ion exchange material. This is done in order to remove all salts present in the water as efficiently as possible. Simultaneously or sequentially, cation exchange resin and anion exchange resin are used during deionization. All salts soluble in water consist of cations and anions. Then the mixture of the two resins in the demineralized water completely replaces them with hydrogen ions H+ and hydroxyl OH-. As a result of the chemical reaction, these ions combine and a water molecule is created. In this process, virtually complete desalination of water occurs. Deionized water has become very widespread in industry, the chemical and pharmaceutical industries, and in industrial leather processing. Previously, such water was used in the production of electron-ray televisions.

Electrodialysis is a method based on the ability of ions to move under the influence of an electric field in water. The concentration of salts is reduced in a volume limited by ion-exchange membranes.

The distillation method is based on evaporation followed by concentration of steam of the treated water. This method of water demineralization has not become widespread, as it is too energy-intensive, moreover, scale forms on the walls of the evaporator during the distillation process.

The most common method of water demineralization is reverse osmosis. This method of water demineralization has long been recognized as highly professional. Initially, the method of water purification by reverse osmosis was proposed for desalination of sea water. However, it was later discovered that the method of water demineralization by reverse osmosis together with filtration and ion exchange can significantly expand the possibilities of water purification.

The principle of water demineralization by the reverse osmosis method is that water is "pushed" through a thin-film semipermeable membrane. The pores of the membrane are so small that only water and low-molecular gases, including oxygen and carbon dioxide, can pass through them. As a result of such treatment, all impurities remain on the membrane and are subsequently drained into the drain.

In terms of cleaning efficiency, membrane systems have no competitors. They are capable of purifying water by 97-99.99% of any type of contaminants. As a result, when using the reverse osmosis method, distilled or highly desalinated water is obtained. The method of water treatment in industry by reverse osmosis has its own characteristics. One of the main such characteristics is that deep cleaning on the membrane can only be carried out for water that has undergone preliminary complex cleaning from sand, rust and other similar water-insoluble suspensions. It is especially important that the water prepared for demineralization is purified from chlorine and organochlorine compounds that can destroy the membrane material.

How can you tell if the water is completely demineralized?

The parameters of the water after demineralization must correspond to the following indicators: the value of specific electrical resistance must be within 3-18 Mho*cm at an aqueous medium temperature of 20°C; the pH level must be 6.5-8; the content of silicic acid - less than 20 μg/l; total hardness - less than 1 mmol/l.

When storing demineralized water in tanks, it is necessary to maintain a given pH level of water. Water tanks are constantly in operation, i.e. the tanks are constantly pumped out and filled. Pumping out and filling with demineralized water is associated with production processes. During water pumping, atmospheric air containing CO2 enters the tank. As a result of water contact with air, CO2 dissolves in water and the properties of demineralized water deteriorate. Read more about this process in the article.

In order to avoid CO2 dissolution in water, a Tank Vent CO2 (carbon dioxide) absorber manufactured by our company Alfaintek is installed on the vent nozzle of the tank. Installation of a Tank Vent CO2 (carbon dioxide) absorber manufactured by Alfaintek on the vent nozzle of the tank allows completely preventing the entry of carbon dioxide into the tank.

To prevent the formation of an oxidizer in water, it is necessary that carbon dioxide practically does not enter the storage tank, which is important in the technological processes of power equipment, in the food industry, for semiconductor and pharmaceutical production and a number of other industries.

This is provided by the Tank Vent CO2 (carbon dioxide) absorber, which is installed on the vent nozzle of the tank, and can be mounted both on the tank and on the ground.

Discover more about Alfaintek Tank Vent CO2 (carbon dioxide) absorber.