LU83961A1 - COMPOSITIONS AND METHOD FOR REMOVAL OF OIL PATCHES FROM THE SURFACE OF WATERS - Google Patents

Description

. L-z · **] with DESCRIPTIVE MEMORY filed in support of a

PATENT INVENTION APPLICATION

formed by the so-called Company: LABOFINA S.A.

for "Compositions and method for removing oil slicks from the surface of water." (Inventors: Messrs. A. Lepain and R. Bronchart)

The present invention relates to new compositions intended for eliminating the layers of oils polluting water, in particular sea water. It also relates to an effective process for combating and eliminating these layers of oils.

Oil pollution of seawater (this term including crude oil as well as crude oil fractions), caused by accidents - - drilling operations at sea, discharge of ballast water or overflows from oil tankers, leads to the formation of a continuous film or oil slick which tends to spread over the surface of. seawater. On the high seas, this water table is harmful because it prevents the transfer, from the atmosphere, of air and light which are essential to marine flora and fauna. In coastal waters, it is responsible for the degradation of beaches and crustacean farms.

A technique widely used to combat oil layers ~ * consists in using dispersing compositions based on surfactants which are applied to these oil layers, most often by spraying. These compositions disintegrate the oil slick into oil droplets and disperse them in the water column below the sea surface to a depth of a few meters. The oil thus treated no longer prevents the transfer of air and light from the atmosphere. In addition, it no longer risks engulfing the solid structures near the coast.

The droplets of oils dispersed under the surface of the sea are then biodegraded by certain microorganisms contained in sea water and which are capable of metabolizing the oil. But this biological degradation is a fairly slow process, so that, by sedimentation, non-degraded oil droplets settle on the seabed of shallow water.

The slowness of this process is explained by the fact that biodegradation requires the presence in very large numbers of microorganisms concentrated at the water-oil interface. At the outset, these microorganisms are few in number and must therefore multiply. To do this, they need not only oxygen, present in water, and carbon, taken from the oil, but also nitrogen and phosphorus. Generally, the concentration of these last two elements is clearly insufficient in seawater.

In order to speed up this process, it has therefore been proposed to add to the seawater the nutrients necessary for the development of microorganisms.

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In particular, mineral salts have been used, such as ammonium salts, nitrates, phosphates. However, these mineral salts are too soluble in water and have almost no affinity for oils. They are too quickly dissolved and diluted in seawater and therefore do not maintain themselves at the water-oil interface, where their presence is required.

It has also been proposed to use, as nitrogen source, organic compounds soluble in hydrocarbons, such as condensation products of urea or melamine with aldehydes. But the problem of i ‘solubility in water also arises. These organic compounds dissociate from the oily medium and are lost in the aqueous phase. Some methods have been proposed to remedy this drawback. Thus, to obtain less soluble products, the condensation products of urea with an aldehyde containing less than four carbon atoms are absorbed by an inert support, then are made lipophilic by coating treatment with using a paraffin or any other protective colloid. These treatments, which require special equipment, increase the cost price of nutrients. In addition, the latter cannot be suspended in the surfactant composition used to disperse the layers of oils, so that two successive treatments are necessary for the separate application of the surfactant composition and the nutritive agents. . Finally, the coating product can be quickly dissolved if the pollutant contains aromatic hydrocarbons, which is always the case when processing “fresh crude oil”.

Other techniques used to reduce the water solubility of nutrients lead to compositions that float on the surface of the water. However, the droplets of dispersed oils are found in the first meters of water below the surface of the sea and, therefore, the nutrient compositions are of no use in promoting the development of microorganisms at the water- oil.

It can therefore be seen that the problem of eliminating the layers of oils which - Μ - drift on the surface of sea water requires the development of new nutritive agents Hposolubles for the microorganisms present in these waters and capable of metabolizing mineral oils. These new agents must provide accelerated and more complete biodegradation of oils, in an economical manner.

In order to meet these two criteria - increased activity and economy - these new nutrients must meet the following conditions:. '- relatively easy preparation from inexpensive materials, - reduced solubility in water, - stability with respect to water (non-hydrolysable, for example), - lipophilic nature, ensuring adsorption on the oil, - low toxicity vis-à-vis marine flora and fauna, - easy dispersion in the surfactant compositions used to combat the oil layers.

The present invention relates to surfactant compositions containing nutritive agents which meet this set of conditions.

The liquid compositions of the invention for dispersing the layers of oils from the surface of sea waters and for promoting the microbiological degradation of these oils by microorganisms living in these waters, essentially contain, as nitrogen source assimilable by microorganisms, a monoalkylguanidinium salt of general formula:

, NH

/

R - NH - C

^ νη2.ηχ, where R is an alkyl radical, saturated or unsaturated, containing from 8 to 20 carbon atoms and X is a halogen or an acid anion.

The monoalkylguanidinium salts can be prepared in a simple and known manner by reaction between the cyanamide H ^ N - C = N and a primary amine salt R - NH2 - HX, where R and X have the meaning given above. May use an amine salt or a mixture of amine salts. After purification, alkylguanidinium salts are obtained, the nitrogen content of which depends on the nature of the radical R and on X, but which is generally around 6.5 to 25% approximately.

The radical R, as well as X, are chosen with a view to obtaining guanidinium salts insoluble in water, having a lipophilic character, soluble or at least easily dispersed in the solvents contained in the compositions for treating oil layers , and stable vis-à-vis these solvents and water. For these reasons, monoalkylguanidinium salts are used in which the alkyl radical R contains between 8 and 20 carbon atoms, most often between about 12 and 18 carbon atoms. On the other hand, X is preferably a halogen or an acid anion, such as CH ^ SO ^, C ^ SO ^, NO ^, HSO ^ or R1 - CgH ^ SO ^, with R representing H or an alkyl radical containing from 1 to 12 carbon atoms.

For economic reasons, we mainly use salts where X represents chlorine or NO ^.

In order to promote the development of microorganisms at the water-oil interface, the monoalkylguanidinium salts, acting as a source of nitrogen, are advantageously used in admixture with a phosphorus compound also acting as a nutritive agent by adding phosphorus. The phosphorus compound can be an alkaline or alkaline earth salt of fatty alcohol phosphoric ester, a salt or an ester of organophosphoric acid, a phosphatide or other similar phosphon compound having a low toxicity with respect to the flora and marine fauna

The esters obtained by neutralization of hexamethylene diamine tetra (methylene phosphonic) acid of formula (H ^ PO ^ Cl · ^) ^ - N (CR ^) gN - () 2 with an amine, eg monoethanolamine or fatty amine at 12-18 carbon atoms, have given interesting results. Phosphatides or phospholipids, including in particular lecithin or kephalin, have the advantage of providing phosphorus and nitrogen at the same time and consequently of strengthening the action of the monoalkylguanidinium salts.

The compositions of the invention comprise at least one surfactant chosen for its low toxicity vis-à-vis marine flora and fauna

Among these surface-active agents, mention may be made of ethoxylated tall oil, mono-or polyesters of polyhydric alcohols, in particular esters of aliphatic carboxylic acids, saturated or not, containing from 12 to 20 carbon atoms, and d alcohols, such as sorbitan, glycerol or polyethylene glycol. Mixtures of two or more of these esters can be used, to which other surfactant compounds can be added, such as, for example, ethoxylated higher aliphatic alcohols, alkaline salts of dialkyl sulfosuccinate or condensation products of oxide of ethylene or propylene oxide on the esters mentioned above.

For the preparation of the compositions of the invention in liquid form, the active constituents are dissolved in a solvent or a solvent mixture which is chosen in particular according to its low toxicity for marine flora and fauna. Examples of solvents that may be mentioned include hydrocarbon liquids containing less than 5%, and preferably less than 3% of aromatic compounds.

Liquid hydrocarbons having 5 to 20 carbon atoms, in particular paraffins, in particular those having 6 to 12 carbon atoms, cycloparaffins, such as cyclopentane and cyclohexane, alkylcycloparaffins and naphthenic hydrocarbons, are used in particular. Aliphatic alcohols having from 1 to 8 carbon atoms and in particular ethyl, propyl and isopropyl alcohols can also be used as solvents. Monoethers of glycols, in particular monoalkyl ethers (where the alkyl radical contains from 1 to! Carbon atoms) of glycols such as mono- or di-ethylene glycol and mono-or di-propylene glycol also constitute interesting solvents. The organic solvent may contain water in an amount which does not exceed that of the organic solvent and which is most often between about 10 and 50%, calculated on the weight of organic solvent.

The role of the solvent is twofold: it facilitates the handling and dispersion of surfactants and, moreover, thanks to its affinity, it promotes the penetration of the final composition into the oil layer. Also, it is advantageous to use a composition where the amount of water (provided that water is present) does not exceed about 25% of the total weight of the organic solvent and water.

The weight ratio between the quantity of surfactants and that of solvent can also vary within wide limits. It is obviously advantageous to use compositions as concentrated as possible, but the amount of solvent present in the composition must be sufficient to dissolve the surface-active compounds and the nutritive agents, as well as to allow the application of the compositions at low temperature. .

It has been observed that compositions containing more than approximately 85% * of surface-active agents and nutritive agents are too viscous at low temperatures and, moreover, lose part of their effectiveness, due to their less good penetration. in the oil layers. On the other hand, compositions containing less than about 30% of surfactants and nutrients are not very effective.

The amount of monoalkylguanidinium salt in the compositions of the invention can vary within fairly wide limits and it can reach or even exceed 35% of the total weight of the composition. This quantity depends on many factors, including in particular the type of guanidinium salt and its nitrogen content, the possible presence of other agents promoting the development of microorganisms, the type of solvent used, etc. compositions containing from 2 to 20%, and in particular from 5 to 15%, by weight of monoalkylguanidinium salt are very effective with regard to the biological degradation of the oil droplets dispersed in sea water.

The compositions of the invention may also contain other constituents providing elements useful for the development of microorganisms. Magnesium and calcium are examples of such elements. 0i introduces them into the compositions in the form of organic salt, in particular in the form of magnesium or calcium alkylbenzenesulfonate. The amount of these additives generally does not exceed 3% of the total weight of the composition.

The application of the dispersing compositions of the present invention to the oil slicks can be carried out by various methods. They can be used as is or after dilution with water. They are sprayed onto the oil slicks, either from planes or from boats, fitted with appropriate devices for distributing the dispersing compositions.

The compositions of the invention meet the specifications currently in force for the dispersing compositions used to remove the oil slicks and they in particular meet the criteria of toxicity, effectiveness. dispersing city and biological degradation.

The toxicity tests consist in subjecting the species Daphnia magna and Artemia salina to increasing doses of the dispersing composition and in determining the quantity of composition leaving alive, after 2> i hours, 50% of the species tested (determination of the LC 50 - 2¾ h).

| The dispersing efficiency is determined according to the MIL method, which consists in pouring 100 cc of crude oil into a tank containing 133 liters of water. 100 cc of a 10% aqueous solution of the dispersing composition to be tested is then added to the crude oil sheet tested and left to act for 1 * 30. The treated oil is dispersed with stirring for 10 minutes. Samples are then taken from the dispersion formed and the oil contained therein is extracted. The dispersing power is given by the percentage of petroleum thus extracted compared to the total quantity of petroleum used.

To determine the evolution of the biological degradation process of the polluting oil, the composition of the invention (200 ppm) is added to unsterilized seawater (700 ml) supplemented with topped crude oil (5000 ppm). The mixture thus obtained is incubated for ^ 41 days at 25 ° C, while stirring (air bubbling), then the residual petroleum is extracted with methylene chloride and subjected to gas chromatography.

Results of these determinations are given in the examples below, which are only illustrative and therefore have no limiting character. 'r ’

Example 1.

Monodododyl guanidinium chloride was prepared from dodecylamine hydrochloride and cyanamide.

A dispersant composition comprising 13 parts (by weight) of sorbitan monolaurate, 47 parts of polyethylene glycol monooleate (molecular weight of glycol = 400), 15 parts of diethylene glycol monobutyl ether, 5 parts of water, was then prepared. parts of the guanidinium salt above, 5 parts of ester of hexamethylene diamine tetra acid (methylene phosphonic) and dodecylamine.

vs

This composition had the following characteristics: t · - toxicity (ppm): daphnia magna 850 ppm artemia salina 1000 ppm - effectiveness (%) 72 - biological degradation: 2.4 higher than a similar composition free of guanidinium salt and phosphorus compound.

Example 2. '

A composition was prepared as in Example 1, but using a guanidinium salt obtained from the hydrochloride of a mixture of primary amines containing from 12 to 18 carbon atoms. ·

The characteristics of this composition, concerning toxicity,; the effectiveness and the biological degradation, were the same as those of the! ··· composition of Example 1.

Example 3.

Mono-decyl-guanidinium nitrate was prepared from decylamine nitrate and cyanamide.

*

A dispersing composition was then prepared comprising 16.75 parts (by weight) of sorbitan mono-oleate, 13.50 parts of sorbitan mono-oleate ethoxylated to about 20 moles of ethylene oxide, 24 parts of sodium salt di-ethylhexyl sulfosuccinate (in 75% aqueous solution), 11.25 parts of water, 12 parts of monoethylene glycol monobutyl ether,

Claims (11)

2.5 parts of diethylene glycol, 15 parts of mono-decyl-guanidinium nitrate and 5 parts of ester of hexamethylene diaminetetra acid (methylene phosphonic) and monoethanolamine. i - 1U - The biological degradation obtained with this composition was 1.8 times higher than with a similar composition free of nutritive agents. 1. Dispersing compositions for eliminating the layers of oils polluting water, in particular sea water, characterized in that these compositions based on surfactant and solvent also contain, as a source of nitrogen assimilable by oil biodegradation microorganisms, a monoalkylguanidinium salt of the general formula, NH R - NH -, where R is an alkyl radical, saturated or not, containing nh2.hx of 8 to 20 carbon atoms, and X is a halogen or an acid anion. 2. Compositions according to claim 1, characterized in that the radical R contains from 12 to 18 carbon atoms. i 3. Compositions according to claim 1, characterized in that X is CH ^ SO ^, 1 1 C ^ j-SOjj, NO ^, HSOjj or R - C ^ H ^ SO ^, where R represents H or an alkyl radical containing from 1 to 12 carbon atoms. t!)) Compositions according to any one of Claims 1 to 3, characterized in that X is Cl or N0 ^. 5. Compositions according to any one of claims 1 to M, characterized in that they contain up to 35% of monoalkylguanidinium salt, based on the total weight of the composition. 6. Compositions according to claim 5, characterized in that they contain “from 2 to 20%, in particular from 5 to 15%, of monoalkylguanidinium salt, based on the total weight of composition. 6. Compositions according to one of claims 1 to 5 characterized in that it: also contains a phosphorus compound acting as a nutritive agent for I * - -11-. i for microorganisms. 7. Compositions according to any one of claims 1 to 6, characterized in that they contain from 30 to 85%, based on the total weight of composition, surfactant, monoalkylguanidinium salt and of phosphorus compound. ! 8. Compositions according to any one of claims 1 to 7> characterized * in that they also contain an alkylbenzenesulfonate of magnesium or calcium, in an amount not exceeding 3% of the total weight of the composition. 9. Compositions according to claim 1, characterized in that the tensi (active agent is chosen from the group comprising ethoxylated tall oil, mono-oi polyesters of polyhydric alcohols, the condensation products of these esters with ethylene oxide or propylene oxide, higher ethoxylated aliphatic alcohols, alkaline salts of dialkyl sulfosuccinates and mixtures thereof. 10. A method for removing oil slicks from the surface of seawater, characterized in that a dispersing composition * according to any one of claims 1 to 9 is sprayed onto the oil slick. 9 Brussels, By proxy from the so-called LABOFINA Company. / \ qyÿowA l i