RU2595654C1 - Method of producing sorbent for removal of oil and oil products from water surface - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods of producing sorbents from vegetable raw material. Method of producing sorbent comprises treatment of pre-dried and ground sheet fall of low-temperature plasma of high-frequency discharge at pressure in discharge chamber 26.6 MPa, anode current 0.5 A and voltage 7.5 kV for 60 seconds. Plasma generating gas used is a mixture of argon with propane in weight ratio of gases 70:30. Sorbent recommended for removal of oil and oil products from water surface.

EFFECT: capacity of produced sorbent is 8 g/g, efficiency of cleaning from oil - 99 % with contact time of 5 minutes.

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Description

The invention relates to methods for producing sorbents from plant materials for the protection of the natural environment. Sorbent is used to remove oil and oil products from the surface of the water.

Known methods for producing sorbents based on plant materials. These types of raw materials include agricultural products. For example, unprocessed buckwheat husk (patent RU 2114064, C02F 1/28, 1998), heat-treated rice husk (patent RU 2259875, B01J 20/24, C02F 1/28, 2005) are used as such raw materials. It is known to use carbonized husk of buckwheat grains (patent RU 2031849, C02F 1/28, 1995) for removing oil and oil products from the surface of the water and from wastewater. To clean water from oil pollution, carbonized husk of rice grains is used (patent RU 2036843, C02F 1/28, 1995).

Sorbents obtained by known methods are characterized by low sorption capacity (up to 6 g / g).

As a prototype, a method for producing a sorbent for removing oil and oil products from liquid media was selected (patent RU 2259874, B01J 20/24, C02F 1/28, 2005). The method includes heat treatment of buckwheat husk at a temperature of 460-700 ° C in a plasma of a high-frequency discharge of reduced pressure.

The disadvantages of this sorbent are the low sorption capacity of 4.0-6.0 g / g and the relatively long contact time of the sorbent with the pollutant.

The claimed invention allows to solve the problem of obtaining a sorbent from plant materials with a higher sorption capacity and shorter contact time with the pollutant, which will quickly eliminate spills, preventing the dissolution of light oil fractions.

The problem is solved by the method of producing a sorbent for removing petrochemical contaminants from the surface of the water, including the treatment of pre-dried and crushed sheet litter with a low-temperature high-frequency plasma discharge at a pressure in the discharge chamber of 26.6 Pa, current strength at the anode of 0.5 A, voltage of 7.5 kV in the presence of propane in a mass ratio of plasma-forming gas argon: propane 70:30 for 60 seconds.

The technical result of the invention is to increase the sorption capacity of the resulting sorbent by 30% and reduce the contact time of the sorbent with the pollutant by three times compared with the prototype.

The invention consists in the following. Leaf litter has a porous structure and has good adsorption properties, which are due to the presence of lignin and cellulose in its composition, in addition, it is a waste when estimated from urban areas. To increase its sorption capacity, plasma treatment of dried and ground litter is carried out. For processing, a low-temperature high-frequency plasma is used at a pressure of 26.6 Pa, a current strength at the anode of 0.5 A, and a voltage of 7.5 kV. Under these conditions, the temperature in the discharge chamber of the high-frequency plasma system is 70-100 ° C. Under these conditions, a change in the structure of the material occurs without decomposition of the organic matrix. The use of propane increases the sorption capacity. The mass ratio of plasma-forming gas argon: propane equal to 70:30, respectively, is optimal for achieving a technical result. The processing time of the sorbent is 60 seconds and is optimal for the process, since with a further increase in the processing time, the sorption capacity practically does not change.

Examples of the method

Example 1. Leaf litter is dried in the open air at a temperature of at least 15 ° C to constant weight, then crushed to a size not exceeding 10 mm. The resulting material is loaded into the chamber of a high-frequency generator in fabric bags. Then create a vacuum in the chamber to a pressure of 26.6 Pa. The plasma gas is heated to a plasma state under the influence of an electromagnetic field. The plasma treatment mode is controlled by setting a voltage of 7.5 V and a current strength of 0.5 A at the plasma torch anode. Together with the plasma-forming gas, argon is fed into the chamber with propane at a gas mass ratio of 70:30, respectively. The gas flow rate is 0.06 g / s. Processing is carried out for 60 seconds.

Example 2. Similar to example 1, the processing time is 30 minutes

For comparison, the sorbent was obtained according to example 1, but without the use of propane.

The sorption capacity of the obtained sorbents was determined as follows: a brass grid was placed in Petri dishes, 20 ml of Devonian oil was poured, and the studied sorbent was applied in a continuous layer in an amount of 1 g. At certain intervals (5, 15, 30, 45, 60 min) using the grids were removed from the test sample, some of the oil was drained from the sample and weighed. Sorption capacity was determined as the ratio of the mass of absorbed oil to the mass of material spent on sorption.

Tests of the efficiency of the sorbent were carried out when collecting oil products from the surface of the water. We used Devonian oil from the Tumutukskoye field.

The test was carried out as follows. A fixed amount of oil was applied to the surface of the model water. Next, the obtained sorbent was applied to the oil slick, and after 5, 15 and 30 minutes the sorbent saturated with oil products was mechanically collected. After purification, water samples were taken and the residual oil content in it was determined by extraction.

The data obtained are given in the table.

As can be seen from the table, the sorbent obtained by the claimed method (example 1), is characterized by a higher sorption capacity in comparison with the prototype. The optimal time of sorption of oil products from the surface of the water is 5 minutes, which is 3 times less compared to the prototype with a higher cleaning efficiency.

Thus, the proposed method allows to obtain a sorbent from leaf litter with a sorption capacity exceeding the sorption capacity of the prototype by 30%. The resulting sorbent has an efficiency of 99% with a shorter contact time of the sorbent with the pollutant compared to the prototype.

Claims (1)

A method of producing a sorbent for removing petrochemical contaminants from the surface of the water, comprising treating the plant material with high-frequency plasma, characterized in that the raw material is pre-dried and ground sheet litter, and the treatment is carried out with a low-temperature plasma of a high-frequency discharge at a pressure in the discharge chamber of 26.6 Pa, when the current strength at the anode is 0.5 A and a voltage of 7.5 kV in the presence of propane, the mass ratio of plasma-forming gas is argon: propane 70:30 for 60 seconds.