About Tripoli

Mosin O. - Ph.D.

Diatomaceous earth - a natural mineral sediment similar diatomite containing 80% active silica SiO2, but containing little organic residue. Chemical composition and diatomaceous earth diatomite is almost the same, but different microstructure. This is explained by the difference in the geological age of the deposits. Diatomite refer to later, and diatomaceous earth - to earlier deposits.

Diatomite consist of fragments of shells of diatoms protozoa preserved their structure in the mineral. Diatomaceous earth - more dense rock in which the starting material completely lost its original shape. Diatomite more porous than diatomaceous earth. Depending on the amount of organic impurities and the presence of iron oxides and diatomaceous earth diatomite color ranges from white to pale yellow.

Diatomaceous earth consists of small spherical opal, chalcedony sometimes globules size 0.01-0.02 mm. Usually a small amount diatomaceous earth contains clayey material grains of glauconite, quartz, feldspars. Plasticity diatomaceous earth depends on the content of clay impurities. Average density diatomaceous earth depending on the field ranges from 2000-3000 kg / m3; 60,2-64% porosity; hardness 1-3. Russia's largest Zikeevskoe deposit located in diatomaceous earth Zhizdrinsky District of Kaluga region. A relatively high porosity and low average density of these species (porosity diatomite piece 85% porosity diatomaceous earth below) determined using diatomaceous earth and diatomite as insulation, filter, building materials, and as absorbents, catalysts, fillers and adsorbents.

Chemical composition in diatomaceous earth (%): SiO2 - 42-67, A12O3 - 5-8, Fe2O3 - 2-3, CaO -11-24, MgO - 0,6-1,2, other components - 11-21. The chemical composition of this mineral, its structure and adsorption properties allow the use of diatomaceous earth as a sorbent for wastewater from oil, petroleum, oils, suspended solids, and others.

Experiments on using diatomaceous earth water treatment indicate a high retention efficiency of suspended solids in the filter on the basis of diatomaceous earth. Preliminary data of water clearing diatomaceous earth shown that it can be used as effectively as carbon sorbents to purify water. For example, there is a patent for water purification from oil products via diatomaceous earth. The invention relates to the field of ecology and is designed to combat pollution by oil products.

A method of purifying water comprises preparing a porous sorption material based on natural minerals (shungite, perlite, diatomaceous earth, diatomaceous earth, flask) with a particle size less than 500 microns, and the thermoplastic hydrophobic polymers having a particle size less than 300 microns. Natural mineral is mixed with a thermoplastic polymer in a ratio of 100 wt. h. The mineral is 25-130 parts by weight polymer obtained mixture is filled molds specific configuration (disks, cylinders, bands, plates), and subjected to heat treatment at the melting point of the polymer for 5-40 min.

For carrying out the method disks, cylinders or ribbon is rotated in an aqueous medium, contaminated with petroleum products, during the rotation of oil adhering to the surface of the continuously removed by scraper devices. Sorbent material in the form of plates are immersed in water contaminated oil, and kept as long as the concentration of oil in the water reaches the allowable value (0.05 mg / l).

After saturation of sorbent oil sorbent material is removed by evacuation or centrifugation, after which the sorption material is used again. The effectiveness of a continuous process of water purification from oil products is 99,6-99,8%. It was also determined the sorption capacity of diatomaceous earth on ions: Ca2 +, Ni2 +, Fe3 +, Pb2 +, F--. It is established that an effective sorbent diatomaceous earth phenol and benzopyrene from aqueous media. We studied ways of modifying diatomaceous earth to improve its sorption properties. Also measured was the maximum adsorption of iron ions (III), manganese (II), copper (II) sulphate-ions to diatomaceous earth.

It is found that in the case of adsorption of iron ions diatomaceous earth (III) and Cu (II) proceeds in the same - the maximum adsorption is 2,88 ± 0,02 mg / g and 2,17 ± 0,03 g / g, respectively. The latter fact allows the use of diatomaceous earth as a sorbent for removal of iron. However, there is one major drawback of diatomaceous earth. Having a well-developed outer surface, diatomaceous earth is characterized by low porosity and low ion-exchange properties.

Therefore, before using natural diatomaceous earth, it must be activated in order to increase its adsorption and ion exchange properties. This can be achieved, for example, diatomaceous earth irradiating ionizing radiation. Developing new ways of modifying diatomaceous earth to produce high quality based on it is an urgent task of sorbents for water purification.