ITMI20102062A1 - PROCEDURE FOR THE TREATMENT OF CONTAMINATED WATER INCLUDING DISSOLVED ORGANIC COMPOUNDS AND OIL DELIVERED OR IN EMULSION - Google Patents

Description

PROCEDURE FOR THE TREATMENT OF CONTAMINATED WATER INCLUDING DISSOLVED ORGANIC COMPOUNDS AND DISPERSED OR EMULSIONED OIL

DESCRIPTION

The present invention relates to a process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil.

More particularly, the present invention relates to a process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil which comprises contacting said water with at least one mesoporous material.

Industrial wastewater that must be treated prior to its disposal or reuse often includes contaminated water including dissolved organic compounds and dispersed or emulsified oil. These waters can come from a variety of industries such as, for example, aluminum and steel manufacturing industries, chemical and / or petrochemical industries, automotive industries, oil industries.

In particular, the oil industries, both during extraction and refining, produce considerable quantities of water. For example, during the extraction both the production water is produced which is extracted together with the oil, and the injection water deriving from the return to the surface together with the hydrocarbons of the water pumped into the well to maintain values of pressure at adequate levels. Said waters generally contain salts; heavy metals; dissolved organic compounds such as, for example, aliphatic and / or aromatic compounds such as, for example, benzene, toluene, ethylbenzene, xylenes (known as BTEX); or their mixtures.

Generally, the production water also includes traces of the chemical additives usually used during well drilling.

Generally, the waters deriving from refining also include methyl-t-butyl ether (MTBE), a chemical additive usually added to gasoline to increase its octane number.

In addition, the petrochemical industries also produce large quantities of contaminated water. Said water generally contains specific organic compounds such as, for example, tetrachlorethylene (PCE), trichlorethylene (TCE), dichlorethylene (DCE), vinyl chloride (VC), or their mixtures.

Both in the waters deriving from the petroleum industries (extraction and refining), and in the waters deriving from the petrochemical industries, it is generally present, given their petroleum origin, dispersed oil or in emulsion.

The oil present in these waters is generally a complex mixture comprising: aliphatic, linear, branched, or cyclic hydrocarbons, such as, for example, n-heptane, 2,4,4-trimethyl-1-pentane, 2 -methylhexane, n-octane, 2,4-dimethylhexane, methylcyclohexane, methylcyclohexene; aromatic hydrocarbons such as, for example, benzene, toluene, ethylbenzene and xylenes (known as BTEX), phenols, alkyl-phenols; polycyclic aromatic hydrocarbons (known as IPAs or PAHs) such as, for example, naphthalene, phenanthrene, pyrene, benzopyrene, benzoanthracene. Furthermore, in said oil, sulfur compounds are generally present (for example, sulphides, disulfides, benzothiophene, dibenzothiophene), nitrogen compounds (for example, quinolines, pyridines), oxygenated compounds (for example, fatty acids, naphthenic acids), in addition to traces of metals (for example, nickel, vanadium, cobalt, chromium, cadmium, lead, arsenic, mercury). Due to the complexity of the mixture described above, the presence of compounds that are not very soluble or insoluble in water and the intermolecular interactions that can occur between the various compounds present in it, molecular aggregates can form which constitute the droplets of oil whose dimensions, varying in depending both on the composition of said mixture and on the concentration of the compounds present in said mixture, they give rise to the so-called oil-in-water emulsion (small droplets), or to dispersed oil (larger droplets).

Consequently, generally, oil is found in these waters in three forms: as a dispersed oil which is present in the form of droplets suspended on the surface of the water; as an oil in emulsion in the form of droplets generally having a size of less than 20 µm, which are dispersed in water; as oil dissolved in water (water-soluble organic compounds present in the above mixture). The quantity of dissolved oil depends on various factors such as, for example: the composition of the oil; the pH, salinity and temperature of the water; the oil / water ratio.

Procedures for removing the organic substances dissolved in these waters are known in the art.

For example, the American patent US 4,648,977 describes a cyclic process for purifying aqueous media containing dissolved organic impurities which comprises contacting a water containing from about 10 ppb (by weight) to about 20,000 ppm (by weight) of dissolved organic compounds with an adsorbent material consisting of an organophilic zeolitic molecular sieve, said zeolitic molecular sieve having pores with a diameter of such size as to allow the adsorption of at least some of said organic compounds, so as to obtain purified water; remove said zeolitic molecular sieve with the organic compounds absorbed by the purified water and at the same time regenerate said molecular sieve and destroy by oxidation at least a part of the adsorbed organic compounds by contacting said molecular sieve with an aqueous solution of a compound having an oxidation potential standard of at least 0.25 volts; and, subsequently, contact the regenerated molecular sieve as described above with the water to be purified. The above procedure is said to be able to avoid secondary pollution problems due to the disposal of the organic compounds removed.

The American patent application US 2004/0206705 describes a process for the treatment of water contaminated by non-polar compounds characterized by the fact that the treatment is carried out on contaminated groundwater and consists in making the water pass through a reactive permeable barrier ( PRB), placed in situ perpendicular to the groundwater flow, whose reactive medium consists of one or more apolar zeolites having a silica / alumina ratio greater than 50 and having structural channels (i.e. pores) of similar size to those of molecules of contaminating compounds. The above procedure is said to be able to remove the non-polar contaminating compounds effectively and selectively with respect to the mineral salts normally dissolved in water.

The American patent US 7,341,665 describes a process for the treatment of water contaminated by non-polar organic compounds and / or heavy metals which consists in circulating the water through a system comprising at least two types of zeolites having a silica / alumina ratio greater than 50, placed in succession, in which the first zeolite through which the water is passed is characterized by a high adsorption capacity and by structural channels (i.e. pores) with dimensions between 7 Ã ... and 50 Ã ..., and the second zeolite is characterized by a high removal capacity and by structural channels (ie pores) with dimensions between 5 Ã… and 7 Ã…. The aforementioned procedure is said to be able to effectively remove the contaminating non-polar organic compounds, both in the case in which they are present in low quantities, and in the case in which they are present in high quantities, thanks to the synergistic effect of the two zeolites.

However, the above-reported processes may have some drawbacks, in particular, in the case of contaminated water in which, in addition to the dissolved organic compounds, dispersed or emulsified oil is also present. In fact, the droplets of dispersed or emulsified oil can obstruct or even block the structural channels (i.e. pores) of the zeolites used, thus leading to a gradual reduction in the efficiency of said processes.

Efforts have therefore been made in the art in order to remove dispersed or emulsified oil from water coming from industrial waste.

For example, Sokolovic and others in the article â € œOily water treatment using a new steady-state fiber-bed coalescerâ €, published in â € œJournal of Hazardous Materialsâ € (2009), Vol. 162, pg. 410-415, describe a process for separating oil from highly contaminated water such as, for example, production water deriving from the oil industry or water deriving from the metal hardening industry (â € œhardening shopâ €) through the use of a coalescing bed. A special configuration of said coalescing bed and the use of two filters are said to ensure good results are obtained.

Zhou and others in the article â € œModified Resin Coalescer for Oil-in-Water Emulsion Treatment: Effect of Operating Conditions on Oil Removal Performanceâ €, published in â € œIndustrial & Engineering Chemistry Researchâ € (2009), Vol. 48 (3 ), pg. 1660-1664, describe a process for separating oil from an oil-in-water emulsion using a modified polystyrene-based resin grafted with cetyltrimethylammonium bromide as the coalescing material. The use of said modified resin is said to be advantageous in the treatment of oil-in-water emulsions thanks to its ability to act both as a demulsifying agent and as a coalescing material.

Ahmadun and others in the review â € œReview of technologies for oil and gas produced water treatmentâ €, published in â € œJournal of Hazardous Materialsâ € (2009), Vol. 170, pg. 530-551, show different techniques for the treatment of production water deriving from the oil and gas industry. In fact, various physical, chemical and / or biological methods of treating said production water are described. However, said review underlines the fact that currently known methods are not able to effectively remove small suspended oil particles and dissolved elements.

However, the processes described above may also have some drawbacks. In fact, as also pointed out in the review reported above, said procedures are not always able to give the desired results, in particular in the treatment of contaminated water including dissolved organic compounds and dispersed or emulsified oil. Furthermore, said processes are generally expensive and unable to ensure the removal of the dispersed or emulsified oil.

The Applicant has therefore posed the problem of finding a process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil capable of effectively removing said dispersed or emulsified oil.

The Applicant has now found that by carrying out said treatment in the presence of at least one mesoporous material, it is possible to effectively remove said dispersed or emulsified oil. Furthermore, the use of said mesoporous material also allows to treat contaminated water containing high quantities of both dissolved organic compounds (i.e. quantity of dissolved organic compounds up to 400 ppm), and dispersed oil or emulsion (i.e. quantity of dispersed oil or in emulsion up to 500 ppm). Furthermore, the use of said mesoporous material allows to remove said dispersed or emulsion oil in quantities greater than or equal to 80% by weight with respect to the total weight of the dispersed or emulsion oil present in said contaminated water.

Therefore, the subject of the present invention is a process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion which comprises putting said water in contact with at least one mesoporous material having an average pore diameter between 25 Ã ... and 500 Ã …, Preferably between 30 Ã… and 200 Ã…, more preferably between 60 Ã… and 100 Ã….

For the purpose of the present description and of the following claims, the definitions of the numerical ranges always include the extremes unless otherwise specified.

In accordance with a preferred embodiment of the present invention, said contaminated water can be chosen from: production water deriving from oil or gas wells; injection water deriving from the return to the surface together with the hydrocarbons of the water pumped into the well to maintain pressure values at adequate levels; water deriving from refining; water from the petrochemical industries; groundwater from refining and / or petrochemical industries.

According to a further embodiment of the present invention, said contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion is groundwater deriving from refining and / or petrochemical industries, and said groundwater is put in contact with at least one mesoporous material by passing it through a reactive permeable barrier (PRB), called reactive permeable membrane (PRB) comprising at least one mesoporous material having an average pore diameter between 25 Ã ... and 500 Ã ..., preferably between 30 Ã ... and 200 Ã…, more preferably between 60 Ã… and 100 Ã….

In accordance with a preferred embodiment of the present invention, said dissolved organic compounds can be: halogenated solvents such as, for example, tetrachlorethylene (PCE), trichlorethylene (TCE), dichloroethylene (DCE), vinyl chloride (VC); aliphatic and / or aromatic compounds such as, for example, methyl-t-butyl ether (MTBE), benzene, toluene, ethylbenzene, xylenes (known as BTEX); or their mixtures.

In accordance with a further embodiment of the present invention, said contaminated water can comprise inorganic compounds such as, for example, salts; heavy metals; chemical additives usually used during well drilling; or their mixtures.

In accordance with a preferred embodiment of the present invention, said dissolved organic compounds can be present in said contaminated water in quantities ranging from 10 ppm to 400 ppm, more preferably between 100 ppm and 300 ppm.

Said dispersed or emulsion oil is a complex mixture comprising: aliphatic, linear, branched, or cyclic hydrocarbons, such as, for example, n-heptane, 2,4,4-trimethyl-1-pentane, 2-methylhexane, n- octane, 2,4-dimethylhexane, methylcyclohexane, methylcyclohexene; aromatic hydrocarbons such as, for example, benzene, toluene, ethylbenzene and xylenes (known as BTEX), phenols, alkyl-phenols; polycyclic aromatic hydrocarbons (known as IPAs or PAHs) such as, for example, naphthalene, phenanthrene, pyrene, benzopyrene, benzoanthracene. Furthermore, in said oil, sulfur compounds are generally present (for example, sulphides, disulfides, benzothiophene, dibenzothiophene), nitrogen compounds (for example, quinolines, pyridines), oxygenated compounds (for example, fatty acids, naphthenic acids), in addition to traces of metals (for example, nickel, vanadium, cobalt, chromium, cadmium, lead, arsenic, mercury).

In accordance with a preferred embodiment of the present invention, said dispersed or emulsion oil can be present in said contaminated water in quantities between 50 ppm and 500 ppm, preferably between 100 ppm and 400 ppm.

In accordance with a preferred embodiment of the present invention, said water can be kept in contact with said mesoporous material for a time between 1 hour and 100 hours, preferably between 4 hours and 80 hours.

It should be noted that the temperature at which the process object of the present invention is conducted is not a critical factor. Generally, this procedure can be carried out at room, groundwater, or water extraction temperatures from the oil well.

In accordance with a preferred embodiment of the present invention, said mesoporous material can have a silica / alumina molar ratio (SAR) between 30 and infinite, preferably greater than or equal to 100.

According to a preferred embodiment of the present invention, said mesoporous material can have a pore volume ranging from 0.3 ml / g to 1.3 ml / g, preferably between 0.5 ml / g and 1.1 ml / g.

According to a preferred embodiment of the present invention, said mesoporous material can have a specific surface area (SBET) greater than or equal to 500 m <2> / g, preferably between 600 m <2> / g and 1200 m <2> / g.

According to a preferred embodiment of the present invention, said mesoporous material can have a completely amorphous structure.

In accordance with a further preferred embodiment of the present invention, said mesoporous material can have a substantially amorphous structure.

For the purpose of the present description and of the following claims, the term â € œsubstantially amorphous structureâ € means a mesoporous material which, despite being composed of amorphous silica, has an ordered structure with uniform pores organized in a hexagonal network having a nest-like structure dâ € ™ ape (â € œhoneycomb-like structureâ €).

Completely amorphous mesoporous materials which can be advantageously used for the purpose of the present invention, can be selected from the mesoporous silico-aluminas of the MSA type described, for example, in the European patents EP 659,478 and EP 812,804 and in the American patent US 5,049,536. Their XRD spectrum (â € œX-ray diffractometryâ €) from powders shows a completely amorphous structure. In the aforesaid patents various processes are also described for the preparation of said mesoporous silico-aluminas, in particular mesoporous silico-aluminas having an average pore diameter less than or equal to 40 Ã….

If you want to obtain a silico-alumina having an average diameter of the pores greater than 40 Ã…, it is possible to operate according to a procedure comprising:

- prepare a mixture starting from a tetraalkylorthosilicate, an alcohol or a C3-C6 alkyl alcohol dialcool, a tetraalkylammonium hydroxide having formula R1 (R2) 3NOH in which R1Ã ̈ a C3-C7 alkyl and R2Ã ̈ a C1o C3-C7 alkyl, in presence of a hydrolysable compound of aluminum, in which the molar ratios are included in the following ranges:

- alcohol / SiO2 = 5 - 12;

- R1 (R2) 3NOH = 0.04 - 0.10;

- H2O / SiO2 = 5 - 10;

- Al2O3 / SiO2 = 0 - 0.01;

- subjecting this mixture to hydrolysis and subsequent gelling at a temperature close to the boiling temperature of the alcohol or of the mixture of alcohols present;

- subject the gel obtained to drying and calcination.

Alternatively, completely amorphous mesoporous materials which can be advantageously used for the purpose of the present invention, can be selected from the mesoporous silico-aluminas of the type:

- MSU described, for example, by Bagshaw and others in: â € œScienceâ € (1995), Vol.

269, pg. 1242-1244;

- KIT-1 described, for example, by Ryoo and others in: â € œStudies in Surface Science and Catalysisâ € (1997), Vol. 105, pg. 45-52.

Substantially amorphous mesoporous materials which can be advantageously used for the purpose of the present invention, can be selected from the mesoporous silico-aluminas of the M41-S type described, for example, by Beck J. S. and others in: â € œJournal of American Chemical Societyâ € ( 1992), Vol. 114, pg. 10834-10843. In particular, among the mesoporous silico-aluminas of the M41-S type, those of the MCM type described, for example, in the international patent application WO 91/11390, can be chosen. Their XRD spectrum (â € œX-ray diffractometryâ €) from powders shows an ordered structure with uniform pores organized in a hexagonal network having a honeycomb-like structure. Preferred is the mesoporous silico-alumina called MCM-41.

Alternatively, substantially amorphous mesoporous materials which can be advantageously used for the purpose of the present invention, can be selected from the mesoporous silico-aluminas called:

- FSM-16 described, for example, by Inagaki S. and others in: â € œJournal of Chemical Societyâ €, â € œChemical Communicationâ € (1993), pg. 680-682;

- HMS-3 described, for example, by Tuel and others in: â € œChemistry of Materialsâ € (1996), Vol. 8, pg. 114-122;

- SBA described, for example, by Huo and others in: â € œChemistry of Materialsâ € (1996), Vol. 8, pg. 1147-1160.

For the purpose of the present invention, said mesoporous material can be used in various forms. In particular, said mesoporous material can be formed by operating according to any process of extrusion, spherulation, tableting, granulation, known in the art. For the purpose of the present invention, said mesoporous material can be in the form of an extrusion containing traditional binders such as, for example, aluminum oxide, bohemite, pseudobohemite. Extrusion generally also involves the use of a peptizing agent that can be mixed with the mesoporous material and the binder before extrusion, until a homogeneous mixture is obtained. At the end of this extrusion, â € œpelletsâ € of different sizes will be obtained. At the end of the extrusion, the â € œpelletsâ € obtained are generally subjected to a calcination stage, for example, at a temperature of 550 ° C, in an air flow, for 10 hours. More details relating to said extrusion can be found, for example, in European patents EP 550,922 and EP 665,055.

As mentioned above, the process object of the present invention allows to treat contaminated water containing high quantities of both dissolved organic compounds (i.e. quantity of dissolved organic compounds up to 400 ppm), and dispersed oil or emulsion (i.e. quantity of dispersed oil or in emulsion up to 500 ppm). Furthermore, the process object of the present invention allows to remove said dispersed or emulsion oil in quantities greater than or equal to 80% by weight, up to 100% by weight, with respect to the total weight of the dispersed or emulsion oil present. in said water.

In order to obtain the removal of dissolved organic compounds at levels defined by the regulatory limits provided for by Legislative Decree 152/2006, the water obtained from the aforementioned treatment can be subjected to further treatment with at least one zeolite.

In accordance with a preferred embodiment of the present invention, said process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil comprises contacting the water obtained from the treatment with at least one mesoporous material with at least one zeolite .

In accordance with a preferred embodiment of the present invention, said zeolite can be chosen from among the zeolites having an average pore diameter between 4.5 Ã… and 7.5 Ã…, preferably between 5 Ã… and 7 Ã… .

According to a preferred embodiment of the present invention, said zeolite can have a silica / alumina molar ratio (SAR) greater than or equal to 200.

In accordance with a preferred embodiment of the present invention, said zeolite can be selected from silicalite, ZSM-5 zeolite, mordenite. Favorite is the ZSM-5 zeolite.

In the case of the use of the reactive permeable barrier (PRB) comprising at least one mesoporous material, the groundwater obtained by passing through said barrier can be made to pass through a reactive pemeable barrier (PRB) comprising at least one zeolite, called zeolite being chosen from one of those described above.

In order to better understand the present invention and to put it into practice, some illustrative and non-limiting examples thereof are reported below.

EXAMPLE 1

Preparation of the MSA mesoporous material with an average pore diameter of 32 Ã…

1.36 g of aluminum triisopropoxide [Al (OC3H7) 3] were dissolved in 162.30 g of an aqueous solution at 11.3% by weight of tetrapropylammonium hydroxide (TPAOH). Subsequently, 208.33 g of tetraethylorthosilicate [Si (OC2H5) 4] diluted in 368 g of ethanol were added.

The solution was left under stirring, at room temperature (25 ° C), until a homogeneous gel was obtained which was left to age at room temperature (25 ° C), for 15 hours, then dried, at 100 ° C, for 1 hour, and finally calcined, at 550 ° C, in air, for 8 hours.

The XRD spectrum (â € œX-ray diffractometryâ €) from powders conducted through a Philips Vertical Diffractometer equipped with a proportional pulse counter and operating with a Cu K-Î ± radiation (lambda = 1.54178 Ã ...), indicates that the product obtained is amorphous.

The product obtained has a SiO2 / Al2O3 molar ratio (SAR) equal to 300. The SiO2 content was measured gravimetrically and the Al2O3 content was determined by ICP-AES spectroscopy (â € œInduced Coupled Plasma-Atomic Emission Spectroscopyâ €) .

0.2 g of the product obtained was degassed, for 16 hours, at 350 ° C, under reduced pressure, by means of adsorption-desorption isotherms of nitrogen (N2) at the temperature of liquid nitrogen (N2), using an ASAP instrument 2010 (Micromeritics), and used for the determination of the morphological properties [i.e. specific surface area (SBET), total specific pore volume (VP), mean pore diameter].

The specific surface area (SBET), evaluated by the linear 2-parameter BET plot in the range p / p ° = 0.01 - 0.15 (C> 0), was found to be equal to 835 m < 2> / g.

Subsequently, the total specific volume of pores (VP) was determined, calculated using the Gurvitsch method at p / p ° = 0.995, which was found to be equal to 0.67 ml / g.

Finally, the average diameter of the pores was determined, operating in accordance with the DFT (â € œDensity Functional Theoryâ €) method, which was found to be equal to 32 Ã….

EXAMPLE 2

Preparation of the mesoporous MSA material with an average pore diameter of 43 Ã…

4.08 g of aluminum triisopropoxide [Al (OC3H7) 3] were dissolved in 162.30 g of an aqueous solution at 11.3% by weight of tetrapropylammonium hydroxide (TPAOH). Subsequently, 208.33 g of tetraethylorthosilicate [Si (OC2H5) 4] diluted in 480 g of n-propanol were added.

The solution was left under stirring, at room temperature (25 ° C), until a homogeneous gel was obtained which was left to age at room temperature (25 ° C), for 15 hours, then dried, at 100 ° C, for 1 hour, and finally calcined, at 550 ° C, in air, for 8 hours.

The XRD spectrum (â € œX-ray diffractometryâ €) from powders conducted through a Philips Vertical Diffractometer equipped with a proportional pulse counter and operating with a Cu K-Î ± radiation (lambda = 1.54178 Ã ...), indicates that the product obtained is amorphous.

The product obtained has a SiO2 / Al2O3 molar ratio (SAR) equal to 100. The SiO2 content was measured gravimetrically and the Al2O3 content was determined by ICP-AES spectroscopy (â € œInduced Coupled Plasma-Atomic Emission Spectroscopyâ €) .

0.2 g of the product obtained was degassed, for 16 hours, at 350 ° C, under reduced pressure, by means of adsorption-desorption isotherms of nitrogen (N2) at the temperature of liquid nitrogen (N2), using an ASAP instrument 2010 (Micromeritics), and used for the determination of the morphological properties [i.e. specific surface area (SBET), total specific pore volume (VP), mean pore diameter +.

The specific surface area (SBET), evaluated by the linear 2-parameter BET plot in the range p / p ° = 0.01 - 0.15 (C> 0), was found to be equal to 993 m < 2> / g.

Subsequently, the total specific volume of pores (VP) was determined, calculated using the Gurvitsch method at p / p ° = 0.995, which was found to be equal to 1.01 ml / g.

Finally, the average diameter of the pores was determined, operating in accordance with the DFT method (â € œDensity Functional Theoryâ €), which was found to be equal to 43 Ã….

EXAMPLE 3

Preparation of the MSA mesoporous material with an average pore diameter of 72 Ã…

208.33 g of tetraethylorthosilicate [Si (OC2H5) 4] diluted in 480 g of n-propanol were added to 162.30 g of an aqueous solution at 11.3% by weight of tetrapropylammonium hydroxide (TPAOH).

The solution was left under stirring, at room temperature (25 ° C), until a homogeneous gel was obtained which was left to age at room temperature (25 ° C), for 15 hours, then dried, at 100 ° C, for 1 hour and finally calcined, at 550 ° C, in air, for 8 hours.

The XRD spectrum (â € œX-ray diffractometryâ €) from powders conducted through a Philips Vertical Diffractometer equipped with a proportional pulse counter and operating with a Cu K-Î ± radiation (lambda = 1.54178 Ã ...), indicates that the product obtained is amorphous.

The product obtained consists of silica alone (molar ratio SiO2 / Al2O3 (SAR) equal to infinity).

0.2 g of the product obtained was degassed, for 16 hours, at 350 ° C, under reduced pressure, by means of adsorption-desorption isotherms of nitrogen (N2) at the temperature of liquid nitrogen (N2), using an ASAP instrument 2010 (Micromeritics), and used for the determination of morphological properties [i.e. specific surface area (SBET), total specific pore volume (VP), mean pore diameter].

The specific surface area (SBET), evaluated by the linear 2-parameter BET plot in the range p / p ° = 0.01 - 0.15 (C> 0), was found to be equal to 667 m < 2> / g.

Subsequently, the total specific volume of pores (VP) was determined, calculated using the Gurvitsch method at p / p ° = 0.995, which was found to be equal to 1.0 ml / g.

Finally, the average diameter of the pores was determined, operating in accordance with the DFT (â € œDensity Functional Theoryâ €) method, which was found to be equal to 72 Ã….

EXAMPLE 4

Contaminated water treatment including dissolved organic compounds and oil in emulsion with MSA mesoporous material having an average pore diameter equal to 72 Ã ...

40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater was placed in contact with 30 mg of mesoporous MSA material having an average pore diameter equal to 72 Ã ... obtained as described in the Example 3, at room temperature (25 ° C), for a period of 24 hours.

Before and after the treatment, the water was subjected to gas chromatography / mass spectrometry (GC-MS) in order to highlight the dissolved organic compounds and the oil in emulsion present in the contaminated water before of the treatment and after the treatment.

Said gas chromatography / mass spectrometry (GC-MS) was carried out using a gas chromatograph â € œPurge and Trapâ €, mod. 4460A, by OI Analytic, equipped with a DB 5MS column with a length of 60 m and an internal diameter of 0.25 mm, and a FID detector (â € œFlame Ionization Detectorâ €) operating under the following conditions:

- carrier gas: helium;

- FID detector temperature: 300 ° C;

- oven temperature: 40 ° C (starting); temperature increase 5 ° C / min up to 300 ° C; permanence at 300 ° C for 10 min.

Figure 1 shows the chromatogram [on the abscissa the analysis time (â € œtimeâ €) is reported (in minutes) and the ordinate shows the abundance (â € œabundanceâ €)] of the dissolved organic compounds and of the oil in emulsion present in the contaminated water as it is, or before treatment with said MSA mesoporous material.

On the other hand, Figure 2 shows the chromatogram [the analysis time (â € œtimeâ €) (in minutes) is shown in the abscissa and the abundance (â € œabundanceâ €)] of dissolved organic compounds is shown in the ordinate and of the oil in emulsion present in the contaminated water after treatment with said mesoporous material MSA.

The comparison of the two chromatograms shows that the treatment with a mesoporous material in accordance with the present invention allows to eliminate the oil in emulsion.

EXAMPLE 5

Contaminated water treatment including dissolved organic compounds and oil in emulsion with MSA mesoporous material having an average pore diameter equal to 72 Ã ...

40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater was placed in contact with 30 mg of mesoporous MSA material having an average pore diameter equal to 72 Ã ... obtained as described in the Example 3, at room temperature (25 ° C), for a period of 24 hours.

Before and after the treatment, the water was subjected to gas chromatographic analysis in order to highlight the dissolved organic compounds and the oil in emulsion present in the contaminated water before the treatment and after the treatment.

This gas chromatographic analysis was carried out in accordance with the UNI 10833-1999 standard: â € œDetermination of highly volatile halogenated and aromatic hydrocarbons - Gas chromatographic method using dynamic headspace (Gas extraction and trapping technique) â €.

Figure 3 shows the chromatogram (A) [the analysis time (in minutes) is shown in the abscissa and the abundance (â € œabundanceâ €)] of dissolved organic compounds and oil in emulsion present in contaminated water as it is, or before treatment with said mesoporous material MSA.

Figure 3 also shows the chromatogram (B) [the analysis time (in minutes) is shown in the abscissa and the abundance (â € œabundanceâ €)] of dissolved organic compounds and Oil in emulsion present in contaminated water after treatment with said MSA mesoporous material.

The comparison of the two chromatograms shows that the treatment with a mesoporous material according to the present invention allows to reduce or even eliminate the characteristic compounds of the oil [circled in the chromatogram (A)].

EXAMPLE 6

Variation of the total organic carbon content (â € œTotal Organic Carbonâ € â € “TOC) in the contaminated water including dissolved organic compounds and oil in emulsion after treatment with MSA mesoporous material having an average pore diameter equal to 72 Ã ...

40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater was placed in contact with 30 mg of mesoporous MSA material having an average pore diameter equal to 72 Ã ... obtained as described in the Example 3, at room temperature (25 ° C), for different times (times shown in Table 1).

Said total organic carbon (â € œTotal Organic Carbonâ € â € “TOC) was determined by combustion using a â € œTOC analyzerâ € capable of determining the total carbon content (â € œtotal carbonâ € â €“ TC) and the content of inorganic carbon (â € œinorganic carbonâ € â € “IC) from which the total organic carbon content (â € œTotal Organic Carbonâ € â €“ TOC) is calculated by difference: the values obtained are shown in Table 1.

TABLE 1

TOC TREATMENT TIMES

(hours) (mg / l)

0 465

24 138

48 83

72 50

From Table 1 it can be seen that after 72 hours of treatment with a mesoporous material in accordance with the present invention, the total organic carbon (â € œTotal Organic Carbonâ € â € “TOC) undergoes a decrease equal to about 90%.

EXAMPLE 7

Change in absorbance in contaminated water including dissolved organic compounds and oil in emulsion after treatment with different materials For this purpose the following samples were prepared:

- 40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater were placed in contact with 30 mg of mordenite, at room temperature (25 ° C), for different times: 5 hours and 24 hours (MOR);

- 40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater were placed in contact with 30 mg of mesoporous MSA material having an average pore diameter equal to 32 Ã ... obtained as described in the Example 1, at room temperature (25 ° C), for different times: 5 hours and 24 hours (32 Ã…); - 40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater were placed in contact with 30 mg mesoporous material MSA having an average pore diameter equal to 43 Ã ... obtained as described in Example 2 , at room temperature (25 ° C), for different times: 5 hours and 24 hours (43 Ã…);

- 40 ml of contaminated water comprising dissolved organic compounds and oil in emulsion deriving from refinery groundwater were placed in contact with 30 mg mesoporous material MSA having an average pore diameter equal to 72 Ã ... obtained as described in Example 3 , at room temperature (25 ° C), for different times: 5 hours and 24 hours (72 Ã…).

The samples thus treated and a sample of water as it is, or not subjected to treatment, were subjected to spectroscopic analysis.

The absorption spectra in ultraviolet and visible (300 nm - 850 nm) shown in Figure 4, were recorded with a double beam UV-Vis-NIR spectrophotometer and double monochromator Perkin Elmer Î »950, with passband of 2.0 nm and steps of 1 nm.

Figure 4 demonstrates how the treatment of water with a microporous material, i.e. mordenite having both pores of 8 atoms with dimensions of 2.6 x 5.7 Ã ..., and pores of 12 atoms with dimensions of 7.0 x 6.6 Ã ..., has a very little effect on the removal of oil in emulsion even after 24 hours of treatment.

Claims (30)

CLAIMS 1. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion which comprises putting said water in contact with at least one mesoporous material having an average pore diameter between 25 Ã… and 500 Ã…. 2. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 1, wherein said mesoporous material has an average pore diameter comprised between 30 Ã… and 200 Ã…. 3. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 2, wherein said mesoporous material has an average pore diameter comprised between 60 Ã… and 100 Ã…. 4. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil according to any one of the preceding claims, in which said contaminated water is chosen from: production water deriving from oil or gas wells; injection water deriving from the return to the surface together with the hydrocarbons of the water pumped into the well to maintain pressure values at adequate levels; water from refining, water from petrochemical industries; groundwater from refining and / or petrochemical industries. 5. Process for treating contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of claims 1 to 3, wherein said contaminated water is groundwater and said groundwater is contacted with at least a mesoporous material by passing it through a reactive permeable barrier (PRB), called reactive permeable membrane (PRB) comprising at least one mesoporous material. 6. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, in which said dissolved organic compounds are: halogenated solvents such as tetrachlorethylene (PCE), trichlorethylene (TCE), dichloroethylene (DCE ), vinyl chloride (VC); aliphatic and / or aromatic compounds such as methyl-t-butyl ether (MTBE), benzene, toluene, ethylbenzene, xylenes (known as BTEX); or their mixtures. 7. Process for treating contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said contaminated water comprises inorganic compounds such as salts; heavy metals; chemical additives usually used during well drilling; or their mixtures. 8. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil according to any one of the preceding claims, in which said dissolved organic compounds are present in said contaminated water in quantities ranging from 10 ppm to 400 ppm. 9. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion according to claim 8, wherein said dissolved organic compounds are present in said contaminated water in quantities ranging from 100 ppm to 300 ppm. 10. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said dispersed or emulsified oil is a complex mixture comprising: aliphatic, linear, branched, or cyclic hydrocarbons , such as n-heptane, 2,4,4-trimethyl-1-pentane, 2-methylhexane, n-octane, 2,4-dimethylhexane, methylcyclohexane, methylcyclohexene; aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylenes (known as BTEX), phenols, alkyl phenols; polycyclic aromatic hydrocarbons (known as IPAs or PAHs) such as naphthalene, phenanthrene, pyrene, benzopyrene, benzoanthracene. 11. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 10, wherein said dispersed or emulsion oil comprises sulfur compounds, nitrogen compounds, oxygenated compounds, traces of metals. 12. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said dispersed or emulsified oil is present in said contaminated water in a quantity comprised between 50 ppm and 500 ppm . 13. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 12, wherein said dispersed or emulsified oil is present in said contaminated water in a quantity comprised between 100 ppm and 400 ppm. 14. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said water is kept in contact with said mesoporous material for a time ranging from 1 hour to 100 hours. 15. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion according to claim 14, wherein said water is kept in contact with said mesoporous material for a time ranging from 4 hours to 80 hours. 16. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil according to any one of the preceding claims, wherein said mesoporous material has a silica / alumina molar ratio (SAR) between 30 and infinite. 17. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 16, wherein said mesoporous material has a silica / alumina molar ratio (SAR) greater than or equal to 100. 18. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said mesoporous material has a pore volume comprised between 0.3 ml / g and 1.3 ml / g . 19. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 18, wherein said mesoporous material has a pore volume comprised between 0.5 ml / g and 1.1 ml / g. 20. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, wherein said mesoporous material has a specific surface area (SBET) greater than or equal to 500 m <2> / g. 21. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 20, wherein said mesoporous material has a specific surface area (SBET) between 600 m <2> / g and 1200 m <2> / g. 22. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsified oil according to any one of the preceding claims, wherein said mesoporous material has a completely amorphous structure. 23. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of claims 1 to 21, wherein said mesoporous material has a substantially amorphous structure. 24. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of the preceding claims, in which the water obtained from the treatment with at least one mesoporous material is put in contact with at least one zeolite. 25. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion according to claim 24, wherein said zeolite is chosen from among zeolites having an average pore diameter between 4.5 Ã ... and 7, 5 Ã…. 26. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion according to claim 25, wherein said zeolite is selected from among zeolites having an average pore diameter comprised between 5 Ã… and 7 Ã…. 27. Process for treating contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of claims 26 to 28, wherein said zeolite has a silica / alumina molar ratio (SAR) greater than or equal to 200. 28. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to any one of claims 24 to 27, wherein said zeolite is selected from silicalite, ZSM-5 zeolite, mordenite. 29. Process for treating contaminated water comprising dissolved organic compounds and dispersed or emulsion oil according to claim 28, wherein said zeolite is ZSM-5 zeolite. 30. Process for the treatment of contaminated water comprising dissolved organic compounds and dispersed oil or in emulsion according to claim 5, in which the groundwater obtained by passing through said reactive permeable barrier (PRB) comprising at least one mesoporous material, is passed through a reactive permeable barrier (PRB) comprising at least one zeolite, said zeolite being defined in accordance with any one of claims 25 to 29.