GB2406853A

GB2406853A - A saponin-containing composition and its use in a method of separating liquid mixtures

Info

Publication number: GB2406853A
Application number: GB0323346A
Authority: GB
Inventors: Peter Whitton
Original assignee: PHYTO RES Ltd
Current assignee: PHYTO RES Ltd
Priority date: 2003-10-06
Filing date: 2003-10-06
Publication date: 2005-04-13
Also published as: GB0323346D0; WO2005035942A1

Abstract

A composition for the separation of a liquid mixture into an aqueous and one or more non-aqueous phases, said mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals. The composition comprises an acid component, a salt component and a saponin. The acid may comprise or consist of one or more of hydrochloric acid, nitric acid, sulphuric acid, citric acid, malic acid, formic acid and hydrofluoric acid. The salt is a metal halide, preferably sodium chloride. The composition comprises an aescin-containing extract, preferably a triterpenoid saponin derived from Aesculus hippocastanum seeds. The composition may be in a dry or substantially dry form, or a liquid in the form of an aqueous or ethanolic solution. The use of the composition as a de-emulsification agent is claimed, as is a method of separating a liquid mixture into an aqueous and one or more non-aqueous phases, said mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals by contacting the composition and the mixture. The composition may be formed in situ in the mixture.

Description

Saponin-containing Composition and its Uses

Field of the Invention

The present invention relates to a composition comprising saponins and a method of separating a liquid mixture of non-miscible aqueous and nonaqueous components into their respective phases using said composition.

Introduction

When drilling for oil through geological strata, a liquid composition commonly know as a 'drilling mud' is used in conjunction with the drilling apparatus. As the drill bit of the apparatus cuts progressively through the rock strata, the cut rock must be removed. This cut rock is normally removed by pumping the drilling mud down to the drill bit, releasing the drilling mud into the area near the drill bit, and then allowing the mixture of cut rock and drilling mud to return to the surface (of the seabed, if the well is offshore, or the ground, if the well is on land) in the gap between the 'drilling string' and the borehole. The drilling mud is then recycled and/or disposed of.

The drilling mud serves a number of purposes in addition to removing the cut rock, which include stabilising the drilled hole to prevent it collapsing under the weight of the surrounding rock, cooling and lubricating the drill bit and controlling corrosion of the metal components of drilling tool.

Drilling mud does not have a 'standard' composition because the most ideal composition varies depending on a number of factors, which include local health, safety and environmental legislation, economic considerations, the depth to which the hole is being drilled and whether the hole is being drilled onshore or offshore.

A drilling mud generally comprises a base fluid, which at the time of writing may be classified into one of three types: water-based muds, synthetic/pseudo-oil based muds and oil-based muds.

Water-based muds may be formed with fresh or sea water or a brine such as aqueous potassium or sodium chloride.

Water-based muds are generally used at shallower depths than oil-based or synthetic/pseudo-oil based muds.

Oil-based muds now generally comprise mineral (paraffinic) oils, as opposed to the formerly used, environmentally harmful diesel oils. These are used typically in the deeper portions of a drill hole and have the advantages over water-based muds of having a lower frictional constant and are stable at higher temperatures than water-based muds.

Synthetic oil-based muds were developed to provide an environmentally acceptable, well performing alternative to oil-based muds. The base liquid may be esters, ethers, poly alpha olefins or linear alpha olefins.

Drilling muds generally contain a number of other components such as inorganic weighting materials (most commonly barite), viscosifiers (e.g. bentonite clay), fluid loss control agents, emulsifiers, brines (for water-based muds), alkaline chemicals (such as Ca(OH) 2, NaOH, KOH, etc. to prevent corrosion of metal components) and lubricants and detergents (for water based muds).

Drilling for oil produces an immense amount of waste 'mud', some of which may be recycled once the solids content has been substantially removed. It has been estimated that a single oil well may lead to 6000 m3 of rock cuttings and mud discharge. When the mud is no longer suitable for drilling, for instance after a number of recyclings, it must be disposed of. Environmental legislation in many countries prevents disposal of oil-based muds into the sea and hence the mud must shipped to, and then be disposed of, on land.

Generally, because of the prolonged amount of physical agitation, combined with the surfactants that may be present in the drilling mud, water that combines with the oil-based mud forms an emulsion or dispersion.

Oil and water emulsions/dispersions, which the present invention aims to assist in separating, may be that produced during drilling of an oil well as described above, or in other areas of industry, such as in industrial waste streams, e.g. in the canning industry, and in the clean-up of industrial oil spills.

Separation of the oil and water components would allow the recycling of components of the emulsions; and easy removal and transport from site of the residual solid matter for disposal elsewhere.

The present invention also relates to the removal of metals (particularly heavy metals) both in the form of suspended metals and dissolved metals from oil/water emulsions.

Prior methods of separating oil and water emulsions and dispersions include filtration, the use of liquorice extracts which are expensive and extremely variable in their action, and the treatment of the emulsion with a strong alkali that saponifies the oil content so that it can be removed by filtration. Waste is often taken offsite to a location where it can be incinerated, and inert ash deposited in landfill. Prior solutions in relation to heavy metals have involved the use of trivalent metal ions e.g. Chromium or Iron in their trivalent form. Trivalent metals can remove other metal ions from solution by acting as a chelating agent and binding the salts together through electrostatic interaction. This leads to the salts precipitating out of solution.

The above solutions to the problem of separating oil and water mixtures into the aqueous and non-aqueous components have a number of disadvantages: (i)They do not allow consistent reclamation of reusable oil and/or other materials from the waste.

(ii)Prior solutions for de-emulsification do not remove heavy metals at the same time as de-emulsification; (iii)Prior solutions for the removal of solutions/emulsions from heavy metals require the use of materials which cause environmental problems, and/or are difficult to transport, and/or are unstable in the required form; and (iv) The quantity of waste is relatively high, with the consequently relatively high cost of transporting the waste to a safer location for disposal.

Summary of the Invention

The present invention thus seeks to address at least some of the problems associated with the methods of the

prior art.

Accordingly, in a first aspect, the present invention provides a composition comprising an acid component, a salt component, and a saponin.

In a second aspect, the present invention provides a method for the separation of a liquid mixture into an aqueous and one or more nonaqueous phases, said mixture comprising an aqueous component and one or more non-water miscible hydrocarbon chemicals, said method comprising providing a composition of the present invention providing a liquid mixture comprising an aqueous component and one or more non-watermiscible hydrocarbon chemicals, contacting the composition and the liquid mixture, and allowing the aqueous phase and the one or more non-aqueous phases to separate whereby the resultant phases form separate layers.

In a third aspect, the present invention provides a method for the removal of hydrocarbon deposits from the surface of, or interior of, a substrate comprising: providing a composition of the present invention in the form of a liquid solution, providing the substrate, contacting the liquid solution of the composition with the substrate and allowing the hydrocarbon deposits to be removed from surface of, or interior of, the substrate.

Brief description of the drawings

Figure 1 shows major glycosides of aescin, with R being either Tiglic acid or Angelic Acid.

Figure 2 shows a chromatogram of the analysis by gas chromatography and mass spectrometry of drilling oil used in the Examples (prior to separation).

Figure 3 shows a chromatogram of the analysis by gas chromatography and mass spectrometry of drilling oil used in the Examples (after separation).

Detailed description of the Invention

The composition of the present invention comprises an acid component. The acid may be a mineral acid or an organic acid. The acid preferably comprises or consists of one or more of hydrochloric acid, nitric acid, sulphuric acid, citric acid, malic acid, formic acid and hydrofluoric acid. Combinations of the above acids could be used. The most preferred acid on the grounds of effectiveness in the present invention is citric acid.

Preferably, the salt component comprises a metal ion and/or a halide ion, oxide, sulphide, nitrate or other ion.

Suitable salts include, but are not limited to, sodium chloride and potassium chloride. Further suitable salts may comprise a metal component from groups 1 (alkali metals) or 2 (alkali-earth metals) of the periodic table. The most preferable salt for use in the present invention is sodium chloride on the grounds of its ready availability, low cost and effectiveness in assisting the other components of the composition to separate the aqueous and non-aqueous components of a mixture.

The composition of the present invention comprises a Saponin. Saponins are types of glycosides. Glycoside molecules consist of a carbohydrate residue, termed an "glycone" component/residue, and a non-carbohydrate residue, termed an "aglycone" component/residue. Saponins are plant glycosides of a high molecular weight that consist of aglycone residues which may be triterpenoid, steroid or steroidal glycoalkaloid moieties chemically, linked to a sugar moiety (the glycone residue) [Hostettmann. K., Hostettmann. M. and Marston. A, (1991) Saponins, Methods in Plant Chemistry 7. 435-471]. The sugar moiety may be, for example, a glucose, an arabinose, a xylose or glucuronic moiety. Saponins are characterized by their bio-surfactant properties and produce a foam when shaken with water. The detergent action of saponins was recognised hundreds of years ago when extracts of Saponaria officinalis, a high saponin-bearing plant, were used to make soap [Osbourn. A, (1996) Saponins and Plant Defence - A Soap Story. Trends in Plant Science. Vol. 1, No. 1. 4-9.] Saponin is a kind of bio surfactant that is produced naturally by various plants and micro organisms. They have both hydrophobic and hydrophilic moieties. The advantages of using saponins are that they are biodegradable, environmentally safe, have a low toxicity and are easy to produce. Therefore, the separation of a mixture into aqueous and non-aqueous phases using saponin is an attractive, cost- effective process.

The saponin component may be present as a plant extract, or a purified compound. The saponins may be 'man- made', i.e. synthesized rather than being extracted from plant materials.

Preferably, the saponin is a triterpenoid saponin.

Triterpenoid saponins suitable for use in the present invention may be derived from the horse chestnut tree. The horse chestnut tree (Aesculus hippocastanum) is a plant that is widely distributed all over the world. It has a resistance to a range of climates, exemplified by the fact that the horse chestnut can grow from the Balkans to the Caucasus [Fournier P. Le Livre des Plantes Medicinales et Veneneuses de France, Tome 2. Paris: P. Lechevalier, 1948: 475-9.]. The part of the plant used in medicine is the seeds. The main constituent of the seeds of Aesculus hippocastanum is a saponin called aescin. Aescin is a natural mixture of triterpene saponins [Costantini A. Escin in pharmaceutical oral dosage forms: quantitative densitometric HPTLC determination. I1 Farmaco 1999; 54: 72832. ] . The aglicones are derivatives of protoascigenin, acylated by acetic acid at C-22 and by either angelic or tiglic acids at C-21 (see Figure 1).

Aescin is well tolerated by many living organisms, including humans. Reports of poisoning with horse chestnut seeds are due to the presence of the toxic principle esculoside and not to aescin [Supplementary drugs and other substances: Aesculus. In: Martin-dale. The Complete Drug Reference, 32nd edn. Pharmaceutical Press, 1999: 1543-4] . Preferably, the triterpenoid Saponin comprises an aescin compound (which is sometimes termed an escin in the literature). Figure 1 shows the chemical structure of a aescin. All forms of aescin are found to work with the present invention, which includes a-aescin [CAS registry number 66795-86-6] and p-aescin [CAS registry number 11072- 93-8]. It has been found that triterpenoid saponins with tiglic or angelic acid component chemically attached to the triterpene moiety of the aescin molecule may be used in the present invention.

In a preferred embodiment of the present invention, the composition comprises an aescin-containing extract of Aesculus hippocastanum L. seeds. The CAS registry number of an aescin-containing extract is (8053-39-2). Such an extract is obtainable from Hammer Pharma S.p.A. The extract may be extracted from the plant material using 80% V/V methanol. The Hammer Pharma specification for the extract indicates that the ratio of vegetable matter to final aescin extract is about 6-8:1.

Preferably, the composition comprises, relative to 1 part by weight of the salt component, 2 to 40 parts by weight of the acid component, more preferably, 10 to 30 parts by weight of the acid component and even more preferably 15 to 25 parts by weight of the acid component.

Ideally, the composition comprises from 18 to 22 parts by weight of the acid component, relative to 1 part by weight of the salt component. If the composition is in liquid form, the weight of the acid component is calculated, for a given volume of liquid, by multiplying the molarity of the acid by the volume of the liquid by the molecular weight of the acid. E.g. lL of 1 molar aqueous hydrochloric acid contains 36.4g of acid compound (on the basis that the molecular weight of HCl is 36.4g).

Preferably, the composition comprises, relative to 1 part by weight of the salt component, 1 to 40 parts by weight of the saponin, more preferably 5 to 20 parts by weight of the saponin and even more preferably 9 to 11 parts by weight of the saponin.

The ratio of the weight of acid component to weight of the saponin in the composition is preferably 1:0.5 to 1:3, and more preferably about 1:2.

It has been found that only a very small percentage of the composition is required to effectively expedite the separation of the aqueous and nonaqueous layers of the liquid mixture. It has been found that the composition will effectively separate the aqueous and non-aqueous layers when the composition is present in amounts of from 0.001 to 0.1 percent by weight of the liquid mixture. In experiments, it was nevertheless found that larger percentages of the composition may be used, indeed up to 20% by weight of the liquid mixture. Preferably, however, on grounds of costs smaller percentages are preferred, that is percentages less than 0.1% of the liquid mixture being separated into aqueous and non-aqueous components. It is demonstrated for a particular composition in the Examples that a smaller percentage of composition (present in an amount of 0.3% by weight of the liquid mixture) separated the aqueous and nonaqueous components of a mixture approximately as well as a moderate amount of the composition (present in an amount of 13% by weight of the liquid mixture).

The composition of the present invention may consist essentially of the salt component, the acid component, the saponin and, optionally, water.

The composition may further comprises water and be in solution form. When in the form of a liquid composition, the preferred molarity of the salt in the solution is from O.1M to 1M, or more preferably from 0.12M to 0.5M, or most preferably from 0.15M to 0.2M. When in solution form, the relative proportions of the acid component, salt component and saponin are as above.

The composition may be in dry or substantially dry form. This may be desirable if there is a need to keep storage and transport costs at a minimum because a dry composition would take up less volume and weigh less than the composition in solution form.

The liquid mixture containing the aqueous and non- aqueous components to be separated may comprise salt water, that is water containing dissolved mineral salts, which may include sodium chloride. The composition of the present invention may be then be formed 'in-situ' in the liquid mixture by adding the acid component and saponin components to the mixture. The present invention also provides a composition comprising a saponin and an acid component. The saponin and acid component are as described in connection with the other composition of the present invention. This composition may be used to add a liquid mixture as described above that further comprises a salt component, in order to form the composition 'in-situ'. Preferably, the ratio of the weight of acid component to weight of the saponin in the composition is preferably 1:0.5 to 1:3, and more preferably about 1:2.

The method of the present invention of separating the aqueous and nonaqueous components of a liquid mixture has been described briefly above. In the context of this document, the word 'immiscible' includes 'immiscible' and substantially immiscible' within its scope. It should be appreciated that some hydrocarbon chemicals may be partially miscible with water at certain temperatures and pressures, i.e. the liquids do not mix in all proportions and at all temperatures and pressures. At certain proportions (of the water and hydrocarbon chemicals), temperatures and pressures, the water and the hydrocarbon chemicals will form two separate phases (layers). At these proportions, temperatures and pressures, the water and hydrocarbon chemicals shall be considered to be immiscible in the context of this document.

Preferably, after contacting the composition of the present invention with the liquid mixture of an aqueous solution/component and non-watermiscible hydrocarbon chemicals, the resulting mixture is physically agitated to ensure distribution of the composition throughout the emulsion/dispersion. Physical agitation includes, but is not limited to, stirring and vibration of the mixing vessel.

The liquid mixture containing the composition is allowed to stand until the aqueous layer and the non-aqueous layer(s) have separated, i.e. separated into the immiscible phases. It may be that two immiscible nonaqueous layers form from the liquid mixture. Commonly, the non-aqueous layers, if composed of hydrocarbons, will be less dense than water and hence 'float' on the aqueous layer.

The non-aqueous layer may then be removed from the mixture, by means known to those skilled in the art, for example, siphoning, centrifugation, draining away the lower layer to leave the top layer.

The non-aqueous liquid may be 'washed' after the removal from the mixture by mixing the non-aqueous liquid with a pure hydrocarbon solvent, e.g. hexane. The hydrocarbon solvent and non-aqueous liquid are then agitated. This hydrocarbon solvent is then removed from the non-aqueous liquid by, for example, centrifugation or other processes known to those skilled in the art.

It is a surprising feature of the present invention that the saponins, particularly the triterpenoid saponins, cause heavy metals present in the liquid mixture to precipitate out of the liquid mixture. This particular aspect of the invention is particularly desirable in the separation of waste drilling muds in the oil industry into aqueous and non aqueous phases. Drilling muds often contain heavy metals as part of their initial composition, or the heavy metals may derive from the rock strata which is being cut and form part of the waste drilling mud. Heavy metals are also derived from the fluids used to counter the pressures that build up in the drilling process.

The present invention also provides the use of a composition of the present invention as a de-emulsification agent. A de-emulsification agent assists in the separation of an emulsion into the separate layers or phases of its components. By "emulsion", this encompasses stable emulsions and also dispersions of one liquid within another, wherein the two liquids are non-miscible.

In the third aspect of the present invention, i.e. the removal of hydrocarbon deposits from a substrate, the substrate may comprise any one or more of rock, clay, sand, soil, earth and wood. An advantage over prior art methods of removal of oil from such substrates is that the end product is not an emulsion. The present invention allows the hydrocarbon deposits and the liquid solution, if the liquid solution is aqueous, to separate into layers.

Embodiments of the present invention will now be described further with reference to the following examples.

The present invention ought not to be construed to be limited only to the following examples.

Examples

The compositions in the following Examples comprise some or all of the following ingredients: Chemical Name CAS Number EINECS Number Sodium Chloride 7647-14-5 231-598-3 Citric Acid 77-92-9 201-069-1 Aesculus Hippocastanum extract 8053-39-2 232-497-7 Method Oil-based waste drilling mud was used to show the effectiveness of the composition. The drilling mud comprised a diesel-type oil and an amide-treated bentonite clay.

The oil-based waste drilling mud was treated by Solid Phase Micro Extraction and its composition analysed by Gas Chromatography with a Mass Spectrometric detector. This analysis of the drilling mud was carried out without the addition of the composition of the present invention, to provide a reference chromatogram with which to compare the oil that has been treated with the composition. This ensures that there was no degradation of the oil by the separation process (see Figure 2 for the resultant chromatogram for drilling mud that has not been treated with the composition). The analysis of the drilling mud is given on the next two pages. The following data corresponds to the chromatogram in Figure 2.

Information from Data File: File: C:\MSDCHEM\1\DATA\JUNE\17070301.D Operator: Peter Date Acquired: 17 Jul 2003 9:47 Method File: SPME Sample Name: gery gunk Misc Info: Vial Number: 1 Search Libraries: C:\Database\NIST02.L Minimum Quality: 90 Unknown Spectrum: Apex Integration Events: Chemstation Integrator - autointl.e Pk# RT Areat Library/ID Ret# CAS' Qual 10.380.03 C:\Database\NIST02.L cis,cis-7,10,-Hexadecadienal 79960 056829- 23-3 95 21.420.01 C:\Database\NIST02.L (7R,8S)-cis-anti-cis-7,8-Epoxyt 41301 073285-35-5 87..

3 1.69 0.07 C:\Database\NIST02.L 2-Azetidinone, 3,3-dimethyl- 3439 007486-91-1 42 4 2.40 0.14 C:\Database\NIST02.L 2,5-Furandione, 3-chloro13712 000096-02-6 25 2.65 0.04 C:\Database\NIST02 L alpha.-d-Lyxopyranoside, methy 60576 002876-90-6 37 6 3.70 0.79 C:\Database\NIST02.L Cyclotrisilaxane, hexamethyl- 71177 000541-05-9 91 7 3.94 0.22 C:\Database\NIST02.L Cyclotrisilaxane, hexamethyl- 71177 000541-05-9 91 8 5.35 0.04 C:\Database\NIST02.L Oxime-, methoxy-phenyl-_ 23717 1000222- 86-6 87 9 6.75 0.02 C:\Database\NIST02.L 2-Anthracenamine 51229 000613-13-8 47 7.10 0.02 C:\Database\NIST02.L Benzene, 1-ethyl-4-methyl- 9135 000622-96- 8 64 11 7.91 0.39 C:\Database\NIST02.L Cyclotetrasilaxane, octamethyl- 115617 000556-67-2 91 12 8.69 0.02 C:\Database\NIST02.L 1-Propane, 3,35-thiobis[2-methyl- 19074 023973-54-8 94 13 8.89 0.03 C:\Database\NIST02.L Benzene, 1,2,4-trimethyl- , 9124 000095- 63-6 95 14 9.09 0.03 C:\Database\NIST02.L l-Hexanol, 2-ethyl13219 000104-76-7 72 9.61 0.02 C:\Database\NIST02.L Butane, 1,3-dimethoxy8563 010143-66-5 27 16 10.18 0.02 C:\Database\NIST02.L Benzene, 1-ethyl-3,5-dimethyl- 14372 000934-74-7 95 17 10.40 0.03 C:\Datobase\NIST02.L Benzene, l-ethenyl-3-methyl- 8702 000100-80-1 64 18 10.91 0.02 C:\Database\NIST02.L Benzene, 1-ethyl-2,3-dimethyl- 14369 000933-98-2 64 17070301.D TEST.x Tue Jul 29 10:53:52 2003 19 11.26 0.07 C:\Database\NIST02.L 2-Ethylacridine 60942 055751-83-2 43 11.69 0.02 C:\Database\NIST02.L Undecane 27120 001120-21-4 90 21 12.33 0.02 C:\Database\NIST02.L 3-Hydroxymandelic acid, ethyl e 136970 1000071-88-9 50 22 12.47 0.07 C:\Database\NIST02.L 13H-Dibenzoa,i]carbazole 98703 000239-64-5 47 23 12.B3 0.15 C:\Database\NIST02.L 1-Octanethiol 21207 000111-88-6 87 24 13.99 0.50 C:\Database\NIST02.L Cyclopentasiloxane, decamethyl- 148041 000541-02-6 50 14.40 0.70 C:\Database\NIST02.L 1,2,4-Trithiolane, 3,5-dimethyl- 24409 023654-92-4 42 26 14.80 0.03 C:\Database\NIST02.L Cyclooctane, methyl- 11173 001502-38-1 64 27 15.30 0.09 C:\Database\NIST02.L Octanoic Acid 19983 000124-07-2 53 28 15.88 0.06 C:\Database\NIST02.L Dodecane 36159 000112-40-3 97 29 16.11 0.05 C:\Database\NIST02.L Pentanoic acid, 4-methyl-, meth 13103 002412-80-8 35 16.27 0.04 C:\Database\NIST02.L 1,2,4-Triazole, 3,5-dithioxo- 14071 005650-03-3 50 31 16.43 0.11 C:\Database\NIST02.L dl-Homoserine 8753 001927-25-9 22 32 17.01 0.11 C:\Database\NIST02.L Silane, (cyclohexyloxy)trimethyl- 38066 013871-89-1 35 33 17.21 0.01 C:\Database\NIST02.L 1,3-Methanopentalene, 1,2,3,5-t 8705 128600-88-4 25 34 17.37 0.04 C:\Database\NIST02.L 2-Cyclopentene-l-carboxylic aci 26483 006894-69-5 27 17.52 0.04 C:\Database\NIST02.L 2-Propanol' 1-(cyclohexylamino)- 28112 000103-00-4 53 36 17.94 0.19 C:\Database\NIST02.L Heptanoic acid, ethyl ester 28787 000106-30-9 22 37 18.43 0.29 C:\Database\NIST02.L Butanoic acid, 2-methyl-, methy 7994 053955-81-0 14 38 18.75 0.18 C:\Database\NIST02.L Butanoic acid, 2-ethyl-2,3,3-tr 28853 038541-67-2 38 39 19.00 0.04 C:\Database\NIST02.L 2,4-Pentanedione, 3-butyl- 27647 001540-36-9 55 19.14 0.07 C:\Database\NIST02.L Dibutyrylamine 28034 004494-12-6 47 41 19.47 0.12 C:\Database\NIST02 L Hydrazine, 1,1-diethyl-2-1-met.,. 13165 067398-39-4 43 42 19.66 0.07 C:\Database\NIST02.L Neodecanoic acid 37194 026896-20-8 53 17070301.D TEST.M Tue Ju1 29 10:53:56 2003 Protocol: First, the amount of composition required for effective separation of the aqueous and nonaqueous components of the liquid mixture was determined by setting up a series of known concentrations. The 'initial composition' consisted of an aqueous solution containing 1M Citric acid, 0.15M Sodium chloride with 10%, by weight, of Aesculus hippocastanum extract. Example 1 had the same composition as the initial composition. The initial composition was then diluted, for Examples 2 to 6, with saline solution, containing 0.9% by weight of sodium chloride, thus forming the Example compositions used to separate the aqueous and non-aqueous components of the drilling mud into layers/phases. The volume of the initial composition and saline solution in each Example added to the drilling mud is shown in Table 1. As can be seen from Table 1, 2 ml of each Example composition was added to 4ml of the drilling mud. Each resultant mixture was then stirred to ensure distribution of the Example composition throughout the mixture.

Table 1. Dilutions used for the separation

Example

Composition 1 2 3 4 5 6 Number Initial Composition 2.00 1.50 0.50 0.25 0. 10 0.05 Saline solution O 0.50 1.50 1.75 1.90 1.95 (0.9%)/ml Volume of Resultant 2.00 2.00 2.00 2.00 2.00 2.00 Composition/ ml Drilling 4.0 4.0 4.0 4.0 4.0 4.0 Mud/ml _ _ After the mixtures containing the drilling mud and the Example compositions were mixed, they were left over night at room temperature to separate each mixture into two fractions (oil/water). The amount of oils collected for each dilution was measured after centrifugation at 4000 rpm for 5 minutes.

Testing: After the effective working concentration of the composition had been determined, it was necessary to show that the separating of the mixtures into aqueous and non aqueous phases was due to a combination of all the ingredients in the composition (i.e. an acid component, a salt component and a triterpenoid saponin component). A series of tests using (1) citric acid, (2) a composition comprising citric acid and horse chestnut extract, and (3) a composition comprising citric acid, horse chestnut extract and sodium chloride was carried out as shown in Table 2. The concentrations of each of these reagents is given in Table 3.

Table 2. Contents of Test Reagents Sample Citric Aesculus Sodium No. Acid hippocastanum chloride 2 + + _ Results The data collected from the protocol test above show that using 0.05 ml of the initial composition (made up to 2ml with 1.95 ml of 0.9% saline solution) for treating a fixed amount of drilling waste (4.0 ml) showed the same amount of oil fraction collected as using 2.0 ml of the initial composition with the same amount of drilling waste. Therefore, it was determined that an Example composition containing 0.05

ml of the initial composition and 1.95 ml of 0.9% saline solution would contain the ideal quantities of the salt component, acid component, and triterpenoid saponin (i.e. Example composition 6) to use for further testing.

In order to prove that the cleaning effect is due to the combination of all of the ingredients, each ingredient used was tested and the amount of oil fraction recovered was measured after mixing 4.0 ml of drilling waste with 2.0 ml of each sample given in Table 3.

Table 3: Results of test performed Vol of Sample oil Refractive Reagents No fractions Index 2ml Citric acid solution aqueous, having a 1 concentration of 0.4% 3.25 1.6506 weight/volume of citric 2ml aqueous solution made from 0.05ml Citric acid solution (concentration as 2 1.25 1.6484 in Sample no. 1) + 1.95 ml of 0.9% Sodium chloride solution 2ml of Example solution 6 3.25 1.6470 Table 3 above clearly show that Sample number 3 (i.e. Example composition number 6) proved the most effective composition as a significant fraction of oil was collected compared to that without the horse chestnut extract, whilst requiring a smaller volume of acid. GC-MS showed that the oil was not degraded by the de-emulsification process (see Figure 3 for the chromatogram).

The oil fractions (layers) of the separated mixtures were very viscous with grey appearance. To these an equal volume of hexane was added to each fraction and placed into a centrifuge at 4000 rpm for 15 minutes. The hexane was removed and the oil fractions were treated by Solid Phase Micro Extraction and analysed by Gas Chromatography. The chromatograms collected for these oil fractions showed they all have the same properties, compared to that of the standard. Figure 3 shows an Example chromatogram for the oil fractions. The data for each peak in this chromatogram is given below on the following two pages.

Inforfflation' from Data Pile: File: C:\MSDCHEM\l\DATA\june\21070307.D Operaeor: P.Whitton Date Acquired: 21 Jul 2003 14:59 Method File: ESSOIL Sample Name: oil fraction Citric acid 0.5 + saponin + NaC1 Misc Info: Vial Number: 63 Search Libraries: C:\Database\NIST02.L Minimum Quality: 90 Unknown Spectrum: Apex Integration Events: Chemstation Integrator autointl.e Pk' RT Area% Library/ID Reft CASt Qual 1 3.17 5.08 C:\Database\NIST02.L Cyclotrisilaxane, hexamethyl- 71177 000541-05-9 91 2,4,6-Cycloheptatrien-l-one, 3, 88Z46 1000161-21-8 78 1,3-Bis(trimethylsilyl)benzene 70584 002060-89-1 64 2 5.46 1.55 C:\Database\NIST02.L Benzene, 1,2,3-trimethyl- 9123 000526-73- B 90 Benzene, 1,3,5-trimethyl- 9121 000108-67-8 89 Benzene, 1,2,4- trimethyl9126 000095-63-6 89 3 8.09 7.58 C:\Database\NIST02.L 1.2,4-Trithiolane, 3,5-dimethyl- 24409 023654-92-4 47 1,2,5-Trithiepane 24403 006576-93-8 38 trans-O-Dithiane-4,5-diol 24396 014193-38-5 25 4 8.72 4.08 C:\Database\NIST02.L lH-Indole-6-carboxylic acid, 2, 60767 056783-99-4 38 1-(p-Tolyl)-2-imidazolidinone 39633 090917-76-3 30 Furanol3,2-b]pyrrole-2carboxhy 60630 155445-47-9 27 11.13 -4.60 C:\Database\NIST02.L Octadecane 91036 000593-45-3 83 Tetradecane 55008 000629-59-4 83 Tetradecane 55009 000629-59-4 83 6 12.23 1.99 C:\Database\NIST02.L 3-(O-Nitrophenyl)-2-oxo-1,3-oxa 62031 090417-72-4 56 Theabromine ethyl 61955 007464-74-6 25 1,10-Phenanthroline, 2,9-dimethyl- 61586 000484-11-7 25 7 12.44 3.85 C:\Database\NIST02.L Nonadecane, 1-chloro- 118727 062016-76- 6 92 1-Chloroeicosane 126142 042217-02-7 92 Docosane 123096 000629-97-0 86 8 13.71 7.22 C.\Database\NIST02.L Octadecane 91037 000593-45-3 92 1-Chloroeicosane 126142 042217-02-7 90 Eicosane 107654 000112-95-8 89 9 14.87 26.17 C:\Database\NIST02.L Heptadecane 82608 000629-78-7 91 Eicosane 107654 000112-95-8 90 Trcosane 130016 000638-67-5 90 15.67 14.81 C:\Database\NIST02.L 1-Hexacosene 146452 018835-33-1 95 1-Bromo-ll-iodoundecane 144636 139123-69-6 78 Tetrapentacontane, 1.54dibromo- 174828 1000156-09-4 76 11 16.00 23.65 C:\Database\NIST02.L Hexacosane 147091 000630-01-3 95 Eicosane 107654 000112-95-8 95 Tricosane 130015 000638-67-5 95 21070307.D ESSOIL.M Mon Jul 21 15:17:54 2003 12,17.25 B.62 C:\Database\NIST02.L l-Hexacosanol 152037 000506-52-5 87 1-Hexacosene 146452 018835-33-1 89 Octacosanol 158478 000557-61-9 78 21070307.D ESSOIL.M Mon Jul 21 15:17:54 2003 The composition and methods of using the composition of the present invention provide cost effective, environmentally acceptable ways of separating the aqueous and non-aqueous compounds of a mixtures or removal of hydrocarbon deposits from a substrate.

Our results show that the composition of the present invention is effective at recovering the lubricating oil fraction from the drilling mud waste. The resultant suspended mixture requires minimal further treatment, for example, with hexane, to purify it to a high enough standard for re-use. GC-MS showed that the lubricating oil was not degraded by the separation process of the present invention.

It has been found that the oil reclaimed by using the method of the present invention is reusable, the water reclaimed is sufficiently pure to be disposed of without special precautions and the quantity of solid waste is relatively small and is easily transportable for disposal off site. In addition, the acid, salt and saponin components of the present invention are chemically stable for extended periods and inexpensive. The components are solid and thus easy to handle and transport. The method of the present invention allows for a one-step process that both separates aqueous and non-aqueous components of a liquid mixture and removes heavy metals from the mixture.

Furthermore, tests have shown that the water phase containing the composition can be re-used to remove further oil from the drilling waste. The hexane, which may be used for washing the recovered oil fraction, may also be re-used after the washing stage. The method is economical, simple to use and safe.

The potential use of the composition of the present invention can extend into cleaning oil spillages. The composition of the present invention can also be used on water-only soluble clays by wetting the oil prior to mixing the oil/powder.

Claims

Claims: 1. A composition for the separation of a liquid mixture into an

aqueous and one or more non-aqueous phases, said mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals, said composition comprising an acid component; a salt component; and a saponin.
2. A composition as claimed in claim 1, wherein the acid component comprises or consists of one or more of hydrochloric acid, nitric acid, sulphuric acid, citric acid, malic acid, formic acid and hydrofluoric acid.
3. A composition as claimed in claim 1 or claim 2, wherein the salt comprises a metal ion.
4. A composition as claimed in claim 3, wherein the metal ion is an alkali metal ion, an alkali-earth metal ion, or a transition metal ion.
5. A composition as claimed in any one of the preceding claims wherein the salt component comprises a halide ion.
6. A composition as claimed in any one of the preceding claims, wherein the salt is sodium chloride.
7.

A composition as claimed in any one of the preceding claims, wherein the saponin is a triterpenoid saponin.
8. A composition as claimed in claim 7, wherein the triterpenoid saponin is a triterpenoid saponin glycoside.
9. A composition as claimed in any one of the preceding claims, wherein the composition comprises a triterpenoid saponin derived from Aesulus hippocastanum seeds.
10. A composition as claimed in any one of the preceding claims, wherein the composition comprises an aescin containing extract.
11. A composition as claimed in claim 10, wherein the aescin-containing extract is derived from Aesulus hippocastanum seeds.
12. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 2 to 40 parts by weight of the acid component.
13. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 10 to 30 parts by weight of the acid component.
14. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 15 to 25 parts by weight of the acid component.
15. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 18 to 22 parts by weight of the acid component.
16. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 1 to 40 parts by weight of saponin component.
17. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 5 to 20 parts by weight of saponin component.
18. A composition as claimed in any one of the preceding claims, wherein the composition comprises, relative to 1 part by weight of the salt component, 9 to 11 parts by weight of saponin component.
19. A composition as claimed in any one of the preceding claims, wherein the ratio of the weight of the acid component to weight of the saponin component is from 1:0.5 to 1:3.
20. A composition as claimed in any one of the preceding claims, wherein the composition is in a dry or substantially dry form.
21. A composition as claimed in any one of claims 1 to 19, wherein the composition is in liquid form.
22. A composition as claimed in claim 21, wherein the liquid is a solution.
23. A composition as claimed in claim 22, wherein the solution is an aqueous or ethanolic solution.
24. A composition as claimed in any one of claims 1 to 19, wherein the composition is formed 'in-situ' in the liquid mixture to be separated into an aqueous and one or more non-aqueous phases.
25. A method as claimed in claim 24, wherein the aqueous component in the liquid mixture comprises a dissolved salt and the composition is formed 'in-situ' by contacting the liquid mixture with the saponin and the acid component.
26. A composition as claimed in any one of claims 1 to 23, further comprising a liquid mixture of an aqueous solution/component and nonwater-miscible hydrocarbon chemicals.
27. Use of a composition as defined in any one of claims 1 to 25 as a deemulsification agent.
28. A method for the separation of a liquid mixture into an aqueous and one or more non-aqueous phases, said mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals, said method comprising providing a composition as claimed in any one of claims 1 to 23, providing a liquid mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals, contacting the composition and the liquid mixture, allowing the aqueous phase and the one or more non-aqueous phases to separate whereby the resultant phases form separate layers.
29. A method for the separation of a liquid mixture into an aqueous and one or more non aqueous phases, said mixture comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals, said method comprising: providing a liquid mixture, comprising an aqueous component and one or more non-water-miscible hydrocarbon chemicals, forming 'in-situ' a composition as defined in any one of claims 1 to 19 in said liquid mixture and allowing the aqueous phase and one or more nonaqueous phases to separate, whereby the resultant phases form separate layers.
30. A method as claimed in claim 29, wherein the aqueous component in the liquid mixture comprises a dissolved salt and the composition is formed 'in-situ' by contacting the liquid mixture with the saponin and the acid component.
31. A method as claimed in any one of claims 28 to 30, wherein the liquid mixture of the aqueous solution and the one or more non-water-miscible hydrocarbon chemicals is in the form of an emulsion or dispersion.
32. A method as claimed in any one of claims 28 to 31, wherein the liquid mixture comprises or consists of drilling mud produced during the drilling of an oil well.
33. A method as claimed in any one of claims 28 to 32, wherein the weight of the composition used to separate the liquid mixture is from 0.001% to 0.1% of the weight of the liquid mixture.
34. A method of preparing a composition as claimed in any one of claims 1 to 24 comprising contacting the acid component, the salt component and the saponin.
35. A method for the removal of hydrocarbon deposits from the surface of, or interior of, a substrate comprising: providing a composition as claimed in any one of claims 1 to 19, in the form of a liquid solution, providing the substrate, contacting the liquid solution of the composition with the substrate, thereby removing the hydrocarbon deposits from the surface of, or interior of, the substrate.
36. A method as claimed in claim 35, wherein the substrate comprises one or more of rock, clay, sand, soil, earth,
37. A method as claimed in claim 35 or 36 wherein the liquid solution comprises water and the hydrocarbon deposits, subsequent to their removal from the substrate, form a separate non-water-miscible layer on or below the aqueous layer.
38. A composition for the separation of a liquid mixture into an aqueous and one or more non-aqueous phases comprising, said mixture comprising an aqueous component and non-water-miscible hydrocarbon chemicals and said composition comprising an acid component; and a saponin.