Water purification from heavy metals is undoubtedlyIt is an important factor in obtaining a ready-to-use, clean and harmless to human fluid. To heavy metals include chemical elements that have metallic properties and at the same time have a significant atomic mass.
Они оказывают разрушительное действие на функции animal and human organisms, and also tend to accumulate in organs and tissues and cause irreparable harm to health. That is why it is important to install water filters from iron, copper, lead, nickel, zinc, cobalt, mercury, cadmium and silver on water treatment plants.
The need for such filtering is due tothe fact that due to the active use of water for various industries, the concentration of these metals in stock is very high. Contaminants have a different structure and properties, which means that for each of their types it is necessary to resort to different methods and devices.
Water purification from heavy metals in the form of ionsproduced by chemical means and reduced to a change in the level of acidity of the medium to the required. When the PH reaches 9.0-10.5, any metals become insoluble and precipitate, which can be easily removed.
The choice of chemicals by which industrial water treatment is performed depends on the following factors:
- the required degree of purification;
- concentration of pollutant;
- the presence or absence of impurities.
После того как вещества переведены в insoluble form, should be the stage of their separation, most often with the help of gravitational deposition of metal. The operation is performed using special precipitating tanks, from which the settled particles are pumped out for dehydration and drying. The advantage of this method is its simplicity, and the minus is highly sensitive to the presence of extraneous compounds that can interfere with the precipitation process. These can be soap, hydrogen peroxide or detergents.
Water purification from heavy metals producedalso in a different way. It is called "membrane" and is carried out using a special installation with partitions. As a rule, in water purified by membranes, the concentration of metals does not exceed 1 mg per liter, and on the other side of the filter they themselves are concentrated in the form of a gel-like mass.
It is this kind of water purification from heavy metals that is considered to be the most effective and promising. Its high quality is due to the special properties of the membranes, such as:
one.High selectivity, or, in other words, the ability to separate different in properties of substances. The partition is semi-permeable and passes only water completely free from impurities. The latter accumulate on the other side of the membranes.
2. The alloy from which the partitions are cast is distinguished by special strength and resistance to chemical attack.
3The membrane equally effectively and fully performs the required functions throughout the entire period of use. The advantage of the method is that metal impurities do not settle on the filtering surface and do not clog its pores, but are removed from the membrane in various ways.
The kind of cleaning is reverse osmosis.This method differs in that a pressure is applied to the solution (polluted water) that exceeds its own. The disadvantages of the method include high requirements to the quality of the materials from which purification plants are created and the difficulty in removing the concentration layer.
Большой объем жидкости с незначительной the concentration of heavy metals is advisable to be purified by ion exchange. As is known, its technology is based on the use of ion exchange resins, on the surface of which metal ions accumulate. Installations for these works allow operating resin for several years, excluding caking.
Наиболее же тщательным методом очистки является the most difficult technical execution cyclic processing with ultrafiltration. However, this method is used only in electrolysis and electroplating plants, the wastewater of which contains a huge percentage of waste solutions and is saturated with chelanites. For such work use special reactors.
