RU2311973C2 - Method of purification of the soils from the heavy metals - Google Patents

Abstract

FIELD: mining industry; chemical industry; other industries; methods of the soils purification from the heavy metals.

SUBSTANCE: the invention is pertaining to the field of biogeotechnology and may be used in the communal services for recultivation of the contaminated soils, in the mining industry, in the chemical industry for salvaging of the polluted sludges and settlings. The method provides for growing of the cultural plants-accumulators on the recultivated soils in compliance with the observance of the agrotechnics rules concerning the cultivated crop and with usage of the stimulating substance - the soils deoxidizer, harvesting the parts of the plants- accumulators, in which the heavy metal is accumulated. Additionally grow the plants excreting the acidifiers into the soil, and through the electrodes located in the near-roots area of the plants-accumulators or connected to the plants-accumulators give the positive and-or negative potential from 1 up to 1000 V. The method allows to recultivate the soils in 5-15 time faster. At that the invention allows to raise fertility and the cadaster value of these soils.

EFFECT: the invention ensures recultivation of the soils in 5-15 time faster, the increased fertility and the cadaster value of these soils.

7 cl, 1 dwg, 12 ex

Description

The present invention relates to biotechnology and can be used in utilities for the remediation of contaminated soils, in the mining of rare, non-ferrous and precious metals, in the chemical industry for the disposal of contaminated sludge and sediments.

A known method of phytoreclamation by growing plants, in particular barley. Barley accumulates during the growing season from 1 ha - not more than 112 g of selenium. To restore the site from selenium (MPC - 565 mg per liter), it will take five years and 4 months to achieve MPC in the soil / Kurkova T.N., Skrypnik L.N. Determination of microgram amounts of selenium in plants by atomic absorption spectroscopy with flow-injection generation of hybrids. // Chemical pollution of the environment and the problems of environmental rehabilitation of disturbed ecosystems: collection of articles. mat. II All-Russian Scientific and Practical Conference. - Penza, 2004 .-- S.100-102 /. Selenium in the soil is in the form of sediment in bound form, part of it is not accessible to plant roots, and it takes a lot of time to bioconcentrate selenium.

It is known to use agroecosystem cleansing due to the introduction of zeolites into the soil / Tsitsishvili G.V. Study of natural zeolites / Adsorbents, their preparation, properties and applications. - L .: Nauka, 1985. - P.121-125 /, the use of zeolites has a temporary effect, since heavy metals are not extracted, but only temporarily bound. Zeolites are valuable and expensive raw materials that are not always located on the territory of the agroecosystem, and therefore inaccessible for widespread use.

There is a method of reclamation of soils contaminated with oil and oil-containing products / RF Patent No. 2009626, АВВ 79/02, 03/30/1994 /, its disadvantage is the use only on soils contaminated with oil and oil-containing products. The specified method does not allow to extract petroleum products from the soil, but only contributes to leaching into the environment.

There is a method of phytoremediation of soils using plants of contaminated batteries / Kerimova Z.M., Islamova F.I. Jerusalem artichoke is a highly ecological and bioenergetic culture of rehabilitation and reclamation of contaminated lands // Chemical pollution of the habitat and problems of ecological rehabilitation of disturbed ecosystems: Sat. mat. II All-Russian Scientific and Practical Conference. - Penza, 2004 .-- P.81-83 /. Use of Oriental Goat (Galega Orientalis) on objects after the Chernobyl explosion / Jerusalem artichoke (Helianthus tuberosus) using in the intermediate trophic chain.

The disadvantage of this method is that the grown plants do not collect and their disposal does not occur, the soil remains after decaying of the plant residues. The use of eroded soils in a limited area due to the large depth of the root system, which will subsequently be a weed in the field of the next crop rotation / L. Lutsenko Agrobioenergetic and radiological assessment of perennial grasses in single-species and mixed crops on eroded soils contaminated with radionuclides. // Chemical pollution of the environment and the problems of environmental rehabilitation of disturbed ecosystems: collection of articles. mat. II All-Russian Scientific and Practical Conference. - Penza, 2004 .-- S.110-115 /.

The closest analogue is a method of inducing hyperaccumulation of metal in the shoots of a plant / RF Application No. 9811945, B09C 1/10, 2000 /, which includes planting a plant in a soil contaminated with one or more metals, cultivating a plant in a soil medium under conditions and over time sufficient for the plant to accumulate metal in its roots, the soil is manipulated to increase the supply of metals from the medium to the plant and the effect of the inducing substance on the plant under conditions and for a time sufficient to induce hyperaccumulation of the metal in the shoots of the plant by the inducing substance. Additional herbicides, additives, acids are added to an acidity of pH 3-5.

The disadvantage is that the plants are in critical conditions, and the environment is additionally polluted by leaching both herbicides and other additives, and due to pollutants in the soil, because the bioaccumulation rate is relatively low.

The objective is to create a method that allows you to remove pollutants from soils, bioaccumulate them, eliminating the ingress of pollutants into the environment, leaching pollutants in the soil of water, under the optimal range of soil composition for the life of purifier plants, shortening the time of land restoration and bioaccumulation.

The problem is achieved in that in the known method of cleaning the soil from heavy metals, including the cultivation of cultivated plants-accumulators on reclaimed soils in compliance with agricultural techniques for cultivated crops and using an inducing substance - soil acidifier, collecting parts of plants, additionally growing plants that produce acidifying substances into the soil, and through electrodes placed in the root zone of the battery plants or connected to the battery plants themselves, a positive ny and / or negative potential of 1 to 1000, contributing to the diffusion of hydrogen ions and / or hydroxyl and / or chelator to the soil, thus creating additional difference soil potentials.

The collection of parts of plant-accumulators is carried out until the concentration of metals in the soil is less than the maximum permissible.

To accelerate the process of movement of ions and complexons, voltage pulses of 1-20 kV and a duration of 1-10 ms are additionally created.

To reduce the viscosity of the aqueous medium during the movement of ions, an additional voltage is applied at a frequency of 19-21 kHz with a frequency equal to the relaxation time of water molecules in plants and / or in the soil.

Additionally, an inducing substance selected from the group comprising organic acids, including lactic, tartaric, pyruvic acid, amino acids, ammonia, urea, hydroxy acids, acetals, chlorophyll, porphyrins, in an amount not exceeding the metal content in the soil, is introduced into the soil .

Impulses are created when soil moisture exceeds 25%, and moisture is determined by soil conductivity.

At a soil moisture content of less than 25%, they saturate the air over plants with aeroions, which create the desired sign of the charge of plants through a spark gap with a voltage of at least 1000 V.

The method is as follows.

The drawing shows a diagram of the method. Plant-accumulator - 1, 2 - electrodes connected to the plant. Option "A" - the electrode is connected to the top of the plant. Option "B" - the electrode is installed directly in the basal part of the plant. 3 - power supply, 4 - grounding electrode, 5 - soil.

In the first year of phytoremediation, the substrate is slightly acidified to pH 5-6 with lactic acid using peat pots on a reclaimed dump in the presence of ion-exchange sorption in it to prevent washing and blowing from surfaces subject to erosion processes. Plants that secrete acidifying substances in the soil (acidifiers) are planted, followed by their collection and disposal. As oxidizing plants, horned lamb, wheat, barley, wormwood, and bracken fern are used.

The second year of phytoremediation includes the selection of bioaccumulative plants to which the electrode is connected, while the second is grounded. During reclamation, there is a constant supply of potential and additional impulses are also applied to increase the number of ions. When a given potential is applied to the electrodes during the growing season during the rainy season, due to the potential difference and the acidic medium in the presence of complexones, the metals diffuse and accumulate in the storage plant, thereby the plant itself becomes a source of metal extraction. Heavy metal in plants accumulates due to the potential difference, which accelerates the osmotic pressure process and moves metal ions in the plant due to osmosis and diffusion, forming it as a sorbent. When combining deoxidizing plants and batteries, the reclamation time can be halved. If the pollutant molecules are not charged, then the introduction of complexon allows you to create a complex - complexon of the pollutant with a charge, and hence the ability to electromigration under the action of electrical potentials. Additionally, to accelerate the physiological processes of accumulation in the plant, a voltage with a frequency of 19-21 kHz is applied to reduce the viscosity of water in the substrate and in the plant. Voltage pulses in a wet substrate with a value of 1-20 kV with a duration of 1-10 ms accelerate the process of movement of ions and complexones in the plant and substrate. Located power lines above the reclaimed field can serve as a means of additional alternating voltage for the electromigration of zwitterions or polar substances. Saturation with aeroions creates the desired sign of the charge of the plants through the arrester with a voltage of at least 1000 V. Power lines equipped with special arrester can also be a source of this voltage. From the experiment it follows that plants grown on the treated substrate with lactic acid and exposed through electrodes due to the potential difference to electric effects accumulated 1.5 times more heavy metals in themselves than in the control versions.

The determination of microgram amounts of substances in plants is carried out by atomic absorption spectroscopy with flow-injection generation of hybrids.

The rate of electromigration of metal ions from soil to plants is determined by the following equations.

where u is the electric mobility;

V is the migration rate, m / s;

X - electric field strength, V / m;

U is the voltage;

L is the distance between plants, m;

τ is the extraction time by the electrochemical method, s.

The bioconcentration coefficient was determined by the equation

where K is the concentration coefficient;

Cp - concentration in the plant, mcg / kg;

Sz - concentration in the soil, mcg / g.

Example 1

Triticum vulgare wheat seeds were placed in two containers containing 0.1113 mg per liter of lead; in the control sample, without creating potential, the bioconcentration coefficient was 47.74 in grain and 42.22 in straw. In the sample for which 14 V was applied to the leaf zone, during the growing season (90 days), the accumulation increased 1.5 times as compared to the control. Bioremediation time is one season.

Example 2

Triticum vulgare wheat seeds were placed in two containers containing 0.1113 mg per liter of lead; in the control sample without building potential, the bioconcentration coefficient was 47.74 in grain and 42.22 in straw. In the sample, which was applied 14 V to the leaf zone, it was additionally watered with a whey solution; during the growing season (90 days), the accumulation increased 2 times in comparison with the control. Bioremediation time is 90 days.

Example 3

Triticum vulgare wheat seeds were placed in two containers containing 0.0016 mg per liter of titanium, and the bioconcentration coefficient in the control sample without building up the potential was 1625 in grain and 15500 in straw. In the sample, 14 V was applied to the zone leaf, during the growing season (90 days), the accumulation increased compared to the control 1.5 times. Bioremediation time is one season.

Example 4

Triticum vulgare wheat seeds were placed in two containers containing 0.0016 mg per liter of titanium, and the bioconcentration coefficient in the control sample without building up the potential was 1625 in grain and 15500 in straw. In the sample, 14 V was applied to the zone leaf, additionally watered with a solution of whey, over the growing season (90 days), the accumulation increased 1.8 times compared with the control.

Example 5

Soybean seeds were placed in two containers containing 1.01 mg per liter of nickel, and the bioconcentration coefficient in the control sample without building up the potential was 2.17 in grain and 14.85 in straw. In the sample, which was applied 14 V to the leaf zone, during the growing season (70 days), the accumulation increased by 1.6 times in comparison with the control.

Example 6

Soybean seeds were placed in two containers containing 1.01 mg per liter of nickel, and the bioconcentration coefficient in the control sample without building up the potential was 2.17 in grain and 14.85 in straw. In the sample, which was fed 14 V into the leaf zone, it was additionally watered with a whey solution; over the growing season (70 days), the accumulation increased 2.0 times compared to the control.

Example 7

Soybean seeds were placed in two containers containing 4.09 mg per liter of strontium in a control sample without creating potential. The bioconcentration coefficient in grains was 3.49, in straw - 8.6. In the sample for which 14 V was applied to the leaf zone, during the growing season (70 days), the accumulation increased in comparison with the control 1.4 times.

Example 8

Soybean seeds were placed in two containers containing 4.09 mg per liter of strontium, and the bioconcentration coefficient in the control sample without potential creation was 3.49 in grain and 8.6 in straw. In the sample, which was fed 14 V into the leaf zone, it was additionally watered with a whey solution; over the growing season (70 days), the accumulation increased 2.0 times compared to the control.

Example 9

Soybean seeds were placed in the soil, in two containers containing 0.318 mg per liter of chromium, in the control sample without building up the potential, the bioconcentration coefficient was 22.95 in grain and 27.35 in straw. In the sample for which 14 V was applied to the leaf zone, during the growing season (70 days), the accumulation increased in comparison with the control 1.4 times.

Example 10

Soybean seeds were placed in the soil, in two containers containing 0.318 mg per liter of chromium, in the control sample without building up the potential, the bioconcentration coefficient was 22.95 in grain and 27.35 in straw. In the sample, which was fed 14 V into the leaf zone, it was additionally watered with a whey solution; over the growing season (70 days), the accumulation increased 2.0 times compared to the control.

Example 11

Triticum vulgare wheat seeds were placed in two containers containing 24.52 mg per liter of barium, and the bioconcentration coefficient in the control sample without building up the potential was 0.044 in grain and 0.25 in straw. In the sample for which 14 V was applied to the leaf zone, during the growing season (90 days), the accumulation increased 1.5 times as compared to the control.

Example 12

Triticum vulgare wheat seeds were placed in the soil, in two containers containing 24.52 mg per liter of barium, in the control sample, without creating potential, the bioconcentration coefficient in grain was 0.044, in straw - 0.25. In the sample, which was applied 14 V to the leaf zone, it was additionally watered with a whey solution; during the growing season (90 days), the accumulation increased 2 times in comparison with the control.

Thus, it has been shown that when creating an additional electric potential in a plant and when acidifying, introducing complexones, bioremediation occurs faster, bioconcentration is intensified. Compared with known methods, bioremediation can be accelerated by 5-15 times.

Using crop rotation with the alternation of selected crops by this method, it is possible to increase the fertility and cadastral value of land.

Claims (7)

1. The method of cleaning the soil from heavy metals, including the cultivation of cultivated plants-accumulators on cultivated soils in compliance with agricultural technology for cultivated crops and using an inducing substance - soil acidifier, collecting parts of accumulator plants in which heavy metal is accumulated, characterized in that grow plants that release acidifying substances into the soil, and through electrodes placed in the root zone of the battery plants or connected to the battery plants themselves provide a positive and / or negative potential from 1 to 1000 V, which facilitates the diffusion of hydrogen ions and / or hydroxyl and / or complexon into the soil, while additionally creating a difference in soil potentials. 2. The method according to claim 1, characterized in that the collection of parts of the plant-accumulators is carried out until the concentration of heavy metals in the soil is less than the maximum permissible. 3. The method according to claim 1, characterized in that it additionally creates voltage pulses of 1-20 kV and a duration of 1-10 ms. 4. The method according to claim 1, characterized in that they additionally apply a voltage with a frequency of 19-21 kHz with a frequency equal to the relaxation time of water molecules in plants and / or in the soil. 5. The method according to claim 1, characterized in that it additionally introduces into the soil a stimulating substance - soil acidifier selected from the group comprising organic acids, including lactic, tartaric, pyruvic acid, amino acids, ammonia, urea, hydroxy acids, acetals, chlorophyll, porphyrins, in an amount not exceeding the content of heavy metals in the soil. 6. The method according to claim 4, characterized in that the pulses are generated when the soil moisture exceeds 25%. 7. The method according to claim 1, characterized in that when the soil moisture is below 25%, they saturate the air over the plants with aero ions, creating the desired sign of the charge of the plants through the arrester with a voltage of at least 1000 V.