WO2016154710A1 - Removal of oil spills from fresh or brine water emulsions by functionalized hydrophobic nanoparticles - Google Patents

Abstract

Adsorbents, methods for making and using adsorbents and for treatment of water contaminated with oil. Adsorbents are functionalized nanoparticles which are hydrophobic. Adsorbents are useful in methods for at least partial removal of oil from freshwater or salt water. Adsorbents are also useful for clean-up of water, particularly briny water, contaminated with oil generated during various oil extraction and processing steps. Adsorbents are also useful for oil removal from water in which stable oil in water emulsions are present. Specific adsorbents are nanoparticles comprising alumina functionalized with petroleum distillation residue.

Description

REMOVAL OF OIL SPILLS FROM FRESH OR BRINE WATER EMULSIONS BY FUNCTIONALIZED HYDROPHOBIC NANOPARTICLES

BACKGROUND OF THE INVENTION

The demand for energy is increasing rapidly worldwide, and consequently, oil production from conventional and unconventional resources is growing. Accordingly, significant amounts of produced brine waters are generated during the exploitation and production processes. Typically, these wastewaters are discharged back into the spent reservoir or into water bodies or tailing ponds. A number of conventional treatment methods to handle such effluent streams have been reported, including reinjecting produced water into spent oil wells, directly discharging it and reusing it in applications such as thermal loops. Of these methods, the reinjection technique is the most efficient way of handling produced water. However, the disposal costs, which include transportation costs, capital costs and infrastructure maintenance costs, may be as much as $4.00 per barrel of water. Also, oil spills which are the release of different types of crude oil into the environment, are a form of pollution that is facing freshwater worldwide. Despite the fact that oil spills in the freshwater bodies involved significant volumes, they do not attract the attention of local or international media as do the marine oil spills. Oil spills on freshwater can cause serious environmental and economic impacts, as they can influence the aquatic and nonaquatic life. Further, the properties and chemistry of the crude oil is strongly dependent on its origin and sources. Accordingly, its behavior in the water body is complex and cannot be easily predicted. For instance, some constituents of crude oil are noted for their tendency to float on water and vaporize; while others preferably bind to solid surfaces. Further, some hydrocarbon compounds of oil constituents can form oil-in-water (o/w) emulsion due to flow turbulence like flow in rivers and consequently the emulsions change the properties and characteristics of oil spills, and hence can become dangerous substances with different toxicological effects on aquatic life and human beings. Several physical, chemical and biological methods have been reported for removal of oil from produced water from onshore activities; including bioremediation, controlled burning, skimming, solidifying, and vacuum and centrifugation. These methods have proven to be expensive, time-consuming and/or ineffective in meeting stringent environment regulations. Owing to their simplicity and applicability at the industrial scale adsorption processes could be employed as an alternate technology for oil spill treatment and recovery. Different types of adsorbents have been widely used for water treatment and recyclability, such as activated carbon, copolymers, organoclay, zeolite and resins.

Therefore, an aim of this invention is to develop a low-cost nano-adsorbent that can be used in the adsorptive removal of oil from water, particularly oily emulsioned freshwater or saltwater (i.e., o/w stable emulsions). The following variables have been investigated to enhance the removal efficiency namely, adsorption time, loading of VR, temperature, salinity and solution pH. SUMMARY OF THE INVENTION

The invention provides adsorption materials and methods for making such materials useful for treatment of water contaminated with oil, e.g., oily water. The materials of the invention are useful in methods for at least partial removal of oil from freshwater or salt water. The materials and methods for oil removal are also useful for clean up of water, particularly briny water, contaminated with oil generated during various oil extraction and processing steps. The materials and methods for oil removal are also useful for oil removal from water in which stable oil in water emulsions are present. The invention provides nanoparticles functionalized by contact with complex hydrocarbon fractions, particularly those fractions of crude oil called residues, residuum or resid. Functionalization with such complex hydrocarbon fractions enhances adsorption of oil onto the nanoparticle. Functionalized nanoparticles of the invention are particularly useful for removal or at least partial removal of oil or oily emulsions from fresh or salt water. In specific embodiments, the nanoparticles are functionalized by contact with crude oil fractions, particularly with inexpensive waste oil fractions and more particularly with fractions that are residues from petroleum distillation. In specific embodiments, nanoparticles are functionalized by contact with petroleum atmospheric distillation residue or petroleum vacuum distillation residue. More specifically, functionalization is carried out by contacting the nanoparticles with a solution of the residue in an appropriate organic solvent, such as toluene. In a specific embodiment, the nanoparticles are contacted with a solution of the residue in the organic solvent containing from about 1 to 6 wt% of residue with respect to the weight of nanoparticles being treated. More specifically, the organic solution for functionalization contains from 1.5 to 4.5 wt% of residue with respect to the weight of nanoparticles being treated. In more specific embodiments, functionalization solutions contain from about 2 to 4 wt% of residue with respect to the weight of nanoparticles being treated. In a specific embodiment, the nanoparticle are functionalized by contact with the solution of petroleum distillation residue for 1 -2 weeks at room temperature.

Nanoparticles useful in the methods of this invention are alumina, silica and combinations thereof that are functionalized as described herein. Additionally useful are functionalized composite nanoparticles comprising magnetic nanoparticles, particular those of magnetic iron oxides, and alumina and optionally silica. Preferred nanoparticles for functionalization and adsorption processes herein are alumina nanoparticles. Composite nanoparticles comprising functionalized alumina are useful in the invention. Preferred composite nanoparticles are core/shell nanoparticles comprising magnetic iron oxide and alumina. Composite nanoparticles can be prepared employing nanoparticles that are already functionalized with hydrocarbon fractions. Alternatively, composite nanoparticles can be functionalized with hydrocarbon fractions after the composite has been formed. In a specific embodiment, core-shell nanoparticles are those where the core is alumina or functionalized alumina and the shell is magnetic iron oxide. In a specific embodiment, core-shell nanoparticles are those where the core is magnetic iron oxide and the shell is alumina or functionalized alumina. In a specific embodiment, core-shell nanoparticles have an iron oxide magnetic core coated with silica and a shell of alumina or functionalized alumina.

The invention provides methods of making nanoparticle adsorbents by functionalization of nanoparticles employing crude oil or complex hydrocarbon fractions of crude oil. In specific embodiments, the fractions employed for functionalization of nanoparticles are petroleum distillation residue fractions and more specifically are petroleum vacuum distillation residue fractions.

The invention provides methods for at least partially removing oil from water contaminated with oil. In specific embodiments, the oil contaminating the water is crude oil originating form a crude oil spill. The water may be fresh water or the water may be sea water or briny water generated by an oil extraction process. Oil in the water to be treated can at least in part be in the form of an oil in water emulsion. In these processes, contaminated water is contacted with functionalized nanoparticles or functionalized composite nanoparticles until a desired level of oil is removed or until the fuctionalized nanoparticles are saturated with oil. Contact may be over minutes, hours, days or weeks dependent upon the level of contamination, environmental conditions, and nanoparticles used. In a specific embodiment, contaminated water is passed through one or more columns containing and retaining functionalized nanoparticles therein. In a specific embodiment, functionalized nanoparticles are added to a selected amount of contaminated water and after adsorption of oil, the nanoparticles are separated from the treated water. When composite nanoparticles containing magnetic materials are employed, any method for magnetic separation of the magnetic nanoparticles from water can be employed. The process for water treatment optionally comprises regeneration of the adsorbents employed. Regeneration can be accomplished by application of heat, such as application of steam or by use of appropriate solvents, e.g., non-polar organic solvents, to remove at least a portion of adsorbed oil. Regeneration of used nanoparticles can provide value added products such as syngas or condensable hydrocarbons.

Other aspects and embodiments of the invention will be apparent to one of ordinary skill in the art on consideration of the detailed description, examples and figures which follow.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 provides graphs showing the amount of oil adsorbed onto (a) virgin alumina, (b) AI/2VR and (c) AI/4VR nanoparticles at pH 7, for initial oil concentrations of 100 (o), 300 (0), and 500 (□) mg/L in fresh water. Other experimental conditions: Adsorbent dose, 2.5 g/L; shaking rate, 600 rpm; Temperature, 298 K.

Figure 2 provides graphs showing the amount of oil adsorbed onto (a) virgin alumina, (b) AI/2VR and (c) AI/4VR nanoparticles at pH 7, for initial oil concentrations of 100 (o), 300 (0), and 500 (□) mg/L in saltwater. Other experimental conditions: Adsorbent dose, 2.5 g/L; shaking rate, 600 rpm; Temperature, 298 K.

Figure 3 provides graphs showing the effect of pH on oil adsorption from freshwater onto (a) virgin alumina, (b) AI/2VR and (c) AI/4VR nanoparticles at pH values 4 (□), 7 (o) and 10 (Δ). Other experimental conditions: Adsorbent dose, 2.5 g/L; shaking rate, 600 rpm; Temperature, 298 K.

Figure 4 provides graphs showing adsorption isotherms for adsorption of oil from saltwater onto nanoparticles of virgin alumina, AI/2VR and AI/4VR at pH (a) 4, (b) 7 and (c) 10. Shaking rate, 600 rpm; temperature, 298 K; amount of adsorbent, 2.5 g/L.

Figure 5 provides graphs showing the effect of VR content on oil adsorption onto alumina (□), AI/2VR (0) and AI/4VR nanoparticles (Δ) at (a) pH 4, (b) pH 7 and (c) pH 10. Adsorbent dose, 2.5 g/L; shaking rate, 600 rpm; temperature, 298 K.

Figure 6 provides graphs showing the effect of temperature on oil adsorption from freshwater onto (a) alumina, (b) AI/2VR and (c) AI/4VR nanoparticles at pH 7 and 283 K (o), 298 K (□), 313 K (Δ) and 328 K (0). Shaking rate, 600 rpm; amount of adsorbent, 2.5 g/L.

Figure 7 provides graphs showing the effect of temperature on oil adsorption from saltwater onto (a) alumina, (b) AI/2VR and (c) AI/4VR nanoparticles at pH 7 and 283 K (o), 298 K (□), 313 K (Δ) and 328 K (0). Shaking rate, 600 rpm; amount of adsorbent, 2.5 g/L.

Figure 8 is a graph showing the amount of NaCI adsorbed onto nanoparticles of virgin alumina, AI/2VR and AI/4VR at pH of 4, 7 and10, for initial NaCI concentration of 500 mg/L. Shaking rate, 600 rpm; temperature, 298 K; amount of adsorbent, 2.5 g/L.

Figure 9 is a graph showing oil adsorption isotherms from saltwater onto virgin alumina and silica nanoparticles at pH 7. Shaking rate, 600 rpm; temperature, 298 K; amount of adsorbent, 2.5 g/L.

Fig. 10 shows a comparison of FT-IR spectra of (a) VR, virgin alumina, AI/2VR (functionalized nanoparticles 2wt%) and AI/4VR (functionalized nanoparticles 4wt%) and (b) the difference spectra between AI/4R and virgin alumina and between AI4RV and virgin VR.

Figure 11 is a schematic illustration of the Adsorption and Subsequent Steam Catalytic Cracking of Oil Technology.

DETAILED DESCRIPTION OF THE INVENTION

The invention is based at least in part on the finding that functionalizing certain nanoparticles with petroleum distillation residue enhances the ability of the functionalized nanoparticles to adsorb oil from water contaminated with oil. More specifically, the functionalized nanoparticles contain alumina. More generally, functionalization of nanoparticles for enhanced adsorption can employ crude oil or fractions thereof generated during petroleum refining. Of particular interest are waste oil fractions and more particularly petroleum distillation residues. Crude oil can be subject to distillation at atmospheric pressure which leaves a petroleum atmospheric distillation residue. Crude oil, including atmospheric distillation residue, can be subjected to vacuum distillation which leaves a petroleum vacuum distillation residue. These residues are complex mixtures of hydrocarbons, the composition of which depends upon the crude oil source, and the temperatures at which atmospheric or vacuum distillation is stopped. Additionally, such residues can be subjected to processes to remove components, for example asphaltene can be extracted from petroleum vacuum residue (VR). Such processed residues can be employed for functionalization. Elemental composition of such residues can be measured and certain art-known methods can provide compositional information on such residues. For example, SARA (saturates, asphaltenes, resins and aromatics) in such resides can be determined. Such residues can also be characterized by predominant carbon number and approximate boiling point. Compositions of such residues can be at least partially characterized by infrared spectroscopy and mass spectrometry methods, for example FT-IR and FT-ICR methods can be employed for such characterization.

Petroleum Distillation Residue or Residuum is a blend of components derived from crude petroleum oil. Petroleum Atmospheric Distillation Residue is the fraction of petroleum that does not distill at atmospheric pressure. Typically, this residue has atmospheric boiling point of greater than about 344°C (650°F). Petroleum Vacuum Distillation Residue (VR) is generally the fraction of petroleum, heavy oil or bitumen that does not distill under vacuum and represent the bottom product in a vacuum distillation column. The composition of a given VR depends upon the source of crude oil. Vacuum Residues (petroleum) designated by CAS Registry Number 64741-56-6 is described as a complex residuum from the vacuum distillation of the residuum from atmospheric distillation of crude oil consisting of hydrocarbons having carbon numbers predominantly greater than C34 and boiling above approximately 495°C (923°F).

In addition to residues, heavy gas oil and vacuum gas oil fractions from petroleum distillation can be employed for functionalization. See: Handbook of Petroleum Processing 2008 (Jones, D.S.J, and Pujado, P, eds) Springer , New York, N.Y. for information on petroleum distillation fractions.

Nanoparticles for use in the present method can range in average size generally from 5 nm to 500 nm. More specifically, nanoparticles for use in the present invention range in average size from 10 to 100 nm. Yet more specifically, nanoparticles useful for the present invention range in average size from 20-50 nm. Preferred nanoparticles for functionalization and use as adsorbents contain alumina. Nanoparticle mixtures of alumina and silica, particularly where alumina is the predominant component of the mixture can also be used. Composite nanoparticles comprising alumina are also useful for functionalization and use herein. In particular core/shell nanoparticles in which the core or shell is alumina are useful herein for functionalization and use herein. Combinations of functionalized alumina

nanoparticles and non-functionalized alumina nanoparticles can be employed as well. More particularly, core/shell nanoparticles comprising a core or shell of magnetic material, such as magnetic iron oxides, e.g., magnetite or maghemite and a shell or core of alumina are useful for functionalization and use herein. In a specific embodiment, nanoparticles having a magnetic iron oxide core coating with silica and having an alumina shell are useful herein for functionalization and use as adsorbents.

Any art recognized method can be employed for preparation of nanoparticles for use herein. Any art recognized method can be employed for preparation of magnetic nanoparticles for use herein. Any art recognized method can be used for

preparation of core/shell nanoparticles for use herein. See: Laurent S. et al. (2008) Magnetic Iron Oxide Nanoparticles: Synthesis, Stabilization, Vectorization,

Physicochemical Characterizations, and Biological Applications, Chemical Reviews, 108, 2064-2 10, for a review of types and preparation methods for magnetic nanoparticles.

Functionalized nanoparticle adsorbents are contacted with oil-contaminated water to remove at least a portion of the oil in the water. The oil may be present in the water in the form of an emulsion, such as an oil in water emulsion. Any form of contacting can be used. Functionalized nanoparticle can be provided in a container which retains the nanoparticles, but which is porous to water and oil, and the container can be placed in contact with oil-contaminated water. The functionalized nanoparticles may be contained in a column or bed through which oil-contaminated water is passed. Treated water can be repassaged through adsorbent columns to improve adsorption. Functionalized nanoparticles can be added to contaminated water in a container for a desired contact time and then separated from the water. Magnetic nanoparticles are particularly useful for ease of separation from water by magnetic separation methods.

Functionalized nanoparticles can be provided as a coating on a substrate and contacting includes contacting the oil contaminated water with the coated substrate. It will be appreciated that the functionalized nanoparticle adsorbents herein can be combined with other materials known in the art to adsorb oil. In specific

embodiments, any such combinations of adsorbents, preferably comprise 50% or more by weight of a functionalized nanoparticle of this invention.

After use as adsorbents, functionalized nanoparticles can be disposed of as appropriate. Alternatively, used adsorbents can be treated to remove adsorbed oil components. Any art recognized method for such removal can be employed. IN an embodiment, used adsorbents can be treated by steam injection or other form of heating to remove adsorbed oil components.

In an embodiment, the invention provides a method for removing oil from water contaminated with oil which comprises contacting the contaminated water with nanoparticles comprising alumina wherein the nanoparticles are functionalized by contact with petroleum distillation residue. In an embodiment, the petroleum distillation residue is petroleum vacuum distillation residue. In an embodiment, the nanoparticles are functionalized alumina nanoparticles. In an embodiment, the nanoparticles are magnetic nanoparticles. In an embodiment, the magnetic nanoparticles further comprise alumina.

In an embodiment, the contaminated water treated is fresh water. In an embodiment, the contaminated water treated is sea water. In an embodiment, the contaminated water treated is generated by an oil extraction process. In an embodiment, the contaminated water has pH of 10 or less. In an embodiment, the contaminated water has pH of 7 or less. In an embodiment, the contaminated water has pH of 4 to 7. In an embodiment, the contaminated water has pH of 6.5 to 8.

In an embodiment, the method of treating contaminated water further comprising a step of measuring pH of the contaminated water prior to contact with the nanoparticles. In a related embodiment, the method of treating contaminated water further comprises adjusting the pH of the contaminated water to a pH of 10 or less after measurement of pH and before contacting. In a related embodiment, the method of treating contaminated water further comprises adjusting the pH of the contaminated water to a pH of 7 or less after measurement of pH and before contacting. In a related embodiment, the method of treating contaminated water further comprises adjusting the pH of the contaminated water to a pH between 4-7 after measurement of pH and before contacting. In a related embodiment, the method of treating contaminated water further comprises adjusting the pH of the contaminated water to a pH of 6 to 8 after measurement of pH and before contacting. In a related embodiment, the method of treating contaminated water further comprises adjusting the pH of the contaminated water to a pH of 6.5 to 7.5 after measurement of pH and before contacting.

In an embodiment pH of the contaminated water is adjusted to a pH of 10 or less before contacting. In an embodiment pH of the contaminated water is adjusted to a pH of 7 or less before contacting. In an embodiment pH of the contaminated water is adjusted to a pH between 4-7 before contacting. In an embodiment pH of the contaminated water is adjusted to a pH of 6 to 8 before contacting. In an embodiment pH of the contaminated water is adjusted to a pH of 6.5 to 7.5 before contacting.

In an embodiment, the temperature of the contaminated water during contact with the functionalized nanoparticles ranges from 273 K to 325K. In an embodiment, the temperature of the contaminated water during contact with the functionalized nanoparticles is ambient temperature. In an embodiment, the temperature of the contaminated water during contact with the functionalized nanoparticles ranges from 280 K to 31 OK.

In an embodiment, the nanoparticles and composite nanoparticles employed for water treatment are functionalized to contain 1 -5 wt% of components of petroleum distillate residue. In an embodiment, the nanoparticles and composite nanoparticles employed for water treatment are functionalized to contain 2-4 wt% of components of petroleum distillate residue.

The invention provides nanoparticles useful in the methods herein which are functionalized to contain 1 -5 wt% of components of petroleum distillate residue. In specific embodiments, the nanoparticles comprise alumina. In specific embodiments, the nanoparticles comprise alumina and silica. In specific embodiments, the nanoparticles comprise alumina and less than 10% by weight silica. In specific embodiments, the nanoparticles consist of alumina. IN specific embodiments, the petroleum distillate residue used for nanoparticle functionalization is petroleum vacuum distillate residue. In specific embodiments, the functionalized nanoparticles comprise components of petroleum distillate residue in addition to asphaltene. In specific embodiments, the components of petroleum distillate residue functionalized on the nanoparticle are less than 15% by weight asphaltene.

In specific embodiments, the functionalized nanoparticles are core/shell nanoparticles. In specific embodiments the core/shell nanoparticles have a core containing magnetic iron oxide. In a specific embodiment, the core/shell nanoparticles have a core containing alumina. In specific embodiments, the functionalized nanoparticles have a magnetic iron oxide core and an alumina shell. In an embodiment, the core/shell nanoparticles have a core that is magnetic iron oxide coated with silica and the shell is alumina.

The invention provides a method for functionalizing nanoparticles to enhance adsorption of oil which comprises contacting the nanoparticle with a crude oil fraction. In an embodiment, the crude oil fraction is a petroleum distillate residue. In an embodiment, the crude oil fraction is a petroleum atmospheric distillation residue. In an embodiment, the crude oil fraction is a petroleum vacuum distillation residue. In an embodiment, the nanoparticles functionalized are an alumina nanoparticles. In an embodiment, the nanoparticles functionalized are a mixture of alumina and silica nanoparticles. In an embodiment, the nanoparticles functionalized are core/shell nanoparticles. In an embodiment, the nanoparticle comprises alumina and magnetic iron oxide. In an embodiment, the nanoparticle consists of alumina and magnetic iron oxide. In an embodiment, the nanoparticle comprises alumina, silica and magnetic iron oxide. . In an embodiment, the nanoparticle consists of alumina, silica and magnetic iron oxide.

In an embodiment, the method for functionalizing the nanoparticles comprises contacted the nanoparticle with a solution of a petroleum distillate residue in a non- polar organic solvent. In a specific embodiment, the non-polar organic solvent is cyclohexane, toluene or xylene. In an embodiment, the solution of a petroleum distillate contains residue in the amount of 1-5wt% with respect to the weight of nanoparticles to be treated. In an embodiment, functionalization is carried out by contacting the nanoparticles for at least one day. In an embodiment, the contacting is carried out for at least one week. In an embodiment, the contacting is carried out between about 280 K to 310 K. In an embodiment, the method further comprises washing the contacted nanoparticle with a non-polar organic solvent which does not absorb in the UV until the wash solvent exhibits no UV absorption. In an embodiment, the wash solvent is toluene or xylene.

Certain details of the present invention have been provided in Franco et al. 2014a and Franco et al. 2014b^{10, 11}. With respect to Franco et al. 2014a details of surface area measurements, particle size measurements and estimation of point of zero charge measurements for nanoparticles are specifically incorporated by reference herein. FT-IR analysis of functionalized nanoparticles and thermogravimetric analysis of nanoparticles are incorporated by reference herein. Details on estimation of VR and Al in the supernatant are incorporated by reference herein. Discussions and details of the Adsorption isotherm model, values of kinetic parameters as provided in Table 3 and values of the estimated parameter of the Dubinin-Ashtakhov model for oil adsorption are incorporated by reference herein. With respect to Franco et al. 2014a, details of the simplex-centroid mixture design for adsorption experiments (page 60) are incorporated by reference herein. Details of alumina and VR leaching tests are incorporated by reference herein as well as the calculated parameters of the cubic model in Table 3. Details of conductivity and absorbance measurements are incorporated by reference herein. The discussions of kinetic models and the Brunauer-Emmet-Teller model are incorporated by reference herein, Discussions of adsorption kinetic and the effect of VR loading are incorporated by reference herein. The estimated parameters of Tables 4 and 5 and discussions of such parameters are incorporated by reference herein. Each of these references is incorporated by reference herein in its entirety for such details, but particularly as specifically described above.

All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and nonpatent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference. All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art, in some cases as of their filing date, and it is intended that this information can be employed herein, if needed, to exclude (for example, to disclaim) specific embodiments that are in the prior art. For example, when a compound is claimed, it should be understood that compounds known in the prior art, including certain compounds disclosed in the references disclosed herein (particularly in referenced patent documents), are not intended to be included in the claim.

When a group is disclosed herein, it is understood that all individual members of those groups and all subgroups, including any isomers and enantiomers of the group members, and classes of compounds that can be formed using the substituents are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure. Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included as individual values in the disclosure.

Every formulation or combination of components described or exemplified can be used to practice the invention, unless otherwise stated. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently. When a compound is described herein such that a particular isomer or enantiomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomers and enantiomer of the compound described individual or in any combination.

One of ordinary skill in the art will appreciate that methods, device elements, starting materials, reagents and synthetic methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such methods, device elements, starting materials, and synthetic methods are intended to be included in this invention.

As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term "comprising", particularly in a description of components of a composition or in a description of elements of a device, is understood to encompass those compositions and methods consisting essentially of and consisting of the recited components or elements. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

Without wishing to be bound by any particular theory, there can be discussion herein of beliefs or understandings of underlying principles relating to the invention. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of the invention can nonetheless be operative and useful.

The term "a" is used herein to describe "one or more than one" items. The term "one" is used herein to refer to one item. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

THE EXAMPLES EXAMPLE 1 :

MATERIALS

A Colombian light crude oil (33°API) and deionized water were used for preparing oil in freshwater emulsions. Oil in saltwater emulsions were prepared using NaCI (99%, Merck KGaA, Germany). HNO₃ (65%, CARLO ERBA Reactifs-SDS, Italy) and NaOH pellets (anhydrous, 98%, Sigma Aldrich, USA) were used for pH adjustment. Alumina nanoparticles purchased from Petroraza, Colombia were used as adsorbent. Silica nanoparticles purchased from Sigma Aldrich was used as adsorbent as well for comparison. A petroleum vacuum residue (VR), with an approximate content of 15 wt% of asphaltenes, supplied by a a refinery (Barrancabermeja-Colombia) was used to functionalize the alumina nanoparticles aiming at increasing their affinity for non-polar components, and improving kinetic and adsorptive capacities in comparison with conventional materials. Elemental analysis showed that virgin VR sample has 78.28 wt% carbon, 14.32 wt% hydrogen, 1.14 wt% sulfur, 4.37 wt% nitrogen and 1.82 wt% oxygen. Toluene (99.5%, Merck KGaA, Germany) was used for washing the alumina nanoparticles functionalized with the VR. All chemicals were used as received without further purifications.

EMULSION PREPARATION

The oil in water (o/w) emulsions were prepared using a Colombian crude oil (33°API) and freshwater. The emulsions were prepared by mixing the oil and freshwater at 16000 rpm for 20 min at 298 K. The mixture pH was around 7. To adjust the pH of the mixture, HNO₃ or NaOH, was used to adjust pH in a range from 4 to 10. The stability of the emulsions was monitored by the size of the oil drop using a RPL3B optical microscope with Rotating Stage Bertrand Lens Mica and Gypsum Plates (Microscopes INDIA, India) and the absorbance using UV-vis spectrophotometer Genesys 10S (Thermoscientific, USA). Stability measurements were performed for 36 h, which was the time for having constant size of oil drop. For the salinity effect studies, NaCI was added to the prepared emulsion to obtain a concentration of 500 mg/L. The properties of the oil freshwater and salt-water emulsions are shown in Table 1.

Table 1. Crude oil, neutral brines and emulsion properties at 298 K.

Sample Density Viscosity PH

(g mL) (cP)

Crude oil 0.860 3.020 7.88

Oil in freshwater emulsion (500 1.017 1.475 7.38 ppm)

Oil in saltwater emulsion (500 1.034 1.500 7.32

PP^m)

NANOPARTICLE PREPARATION

Alumina nanoparticles were washed and posteriorly dried at 393 K for 3 h. To enhance their surface functionality and hydrophobicity, the alumina nanoparticles were functionalized using a solution of VR (vacuum residue) in toluene at selected concentration (e.g., 2 wt% or 4 wt% of VR with regard to the amount of nanoparticles to be treated) for two weeks at 298 K and constant stirring at 200 rpm. During the functionalization process, it is believed that diffusion and physical adsorption of VR occurs on the alumina nanoparticle surface forming an egg-shell profile.^1"4 This adsorption process is fast because the alumina nanoparticles are non-porous and hence there should be no intraparticle diffusion limitation. Because the alumina surface can be considered an array of Bronsted acid-base sites,⁵' ⁶ other mechanisms of VR anchoring on the alumina surface could be due to strong ionic interactions (i.e., Bronsted acid-base interactions) between the organic compounds present in the VR and the surface of alumina nanoparticles. · ⁵· ⁷ After the functionalization process, functionalized alumina nanoparticles were collected after decanting the supernatant. After that, the nanoparticle functionalized with VR were left to dry for a period of 6 h at 393 K to eliminate any remaining solvent and allow the dissolved VR transportation throughout the alumina surface.² Then, the functionalized nanoparticles were washed with toluene several times until the UV-vis absorbance of effluent matched the blank. The resultant functionalized nanoparticles were left to dry at 298 K until no change in mass was observed.

EXAMPLE 2:

PREPARATION OF CORE-SHELL-TYPE PARTICLES

1. Core-shell type particles where the core is composed of alumina nanoparticles functionalized with VR (e.g., 2 wt% or 4 wt%), and the shell is Fe₃0₄ nanoparticles. Fe₃0 nanoparticles are prepared by co-precipitation of ferric and ferrous salts under N₂ gas.⁸ For this purpose, 16.25 g of FeCI₃ and 6.35 g of FeCI₂ are dissolved in 200 ml_ of deoxygenated distilled water. After stirring for 60 minutes, chemical precipitation is achieved at 303 K under vigorous stirring by adding a stoichiometric solution of 2M NaOH under N₂ gas. The reaction system is kept at 343 K for 5 h with solution pH of about 12. Completed precipitation of Fe₃0₄ is expected at pH between 8 and 14.⁹ After the system is cooled to room temperature, the nanoparticles are separated from solution using a permanent magnet and washed with distilled water until the pH of the wash is neutral. Finally Fe₃0₄ particles are washed with acetone and dried in an oven at 333-343 K. This process provides magnetite particles which exhibit super paramagnetic properties.⁸ Functionalized alumina nanoparticles as described above are placed in a solution of deionized water, ethanol and NH₄OH 0.1 -0.5 M at ratio of 1 :1 :0.19 per gram of nanoparticles, this mixture is stirred for 2 hours at room temperature. Fe₃0₄ nanoparticles as synthetized above are then added in the desired amount (1 to 5 wt%) relative to the functionalized alumina nanoparticles and stirred for 4 hours at room temperature. Core-shell nanoparticles are then washed 3 times with ethanol and centrifuged at 4500 rpm for 4 minutes in between each washing. Finally, the resultant core-shell particles are dried in oven at 343 K for 10 hours.⁸

Alternatively, the core-shell nanoparticles can be formed employing alumina nanoparticles that have not been functionalized. In this case, the core-shell nanoparticles are functionalized as described above after they are prepared.

Preparation of Core-Shell Nanoparticles (Fe₃0₄ core/Alumina shell)

2. Fe₃0₄ core/Alumina shell nanoparticles are prepared essentially as in Liu et al. (2008)¹² Fe₃0₄ nanoparticles prepared as above are suspended in deionized water (0.2 g/40ml_) by sonication under nitrogen atmosphere. To this suspension, aqueous sodium silicate solution (0.6% by wt, pH 9, 40 mL) is added, and the resulting mixture is stirred for 24 h at 37 °C to provide a silica coating on the surface of the magnetic nanoparticles. The magnetic nanoparticles are rinsed with deionized water (3 x 40 mL) and resuspended in deionized water (40 mL). Aluminum isopropoxide (alumina precursor, 20 mg) is then added to the suspension which is then sonicated for 30 min at room temperature. The mixture is heated in a closed vial at 80 °C with vigorous stirring for 1 h. The vial is then opened to release 2-propanol gas and the opened vial is then heated at 90 °C for 30 min. The vial is loosely capped and heated at 90 °C for another 2.5 h. The mixture is cooled to room temperature and the core/shell nanoparticles are collected by magnetic collection. Particles are rinsed with water several times and collected. These core/shell nanoparticles are functionalized with hydrocarbons (e.g., VR) as described above.

Example 3:

CHARACTERIZATION OF NANOPARTICLES

Nanoparticles and functionalized nanoparticles were characterized by specific surface (S_BET), particle size, point of zero charge (pH_pzc) and the rmogravi metric analyses. The BET surface of the nanomaterials was measured by N 2 physisorption at 77 K using an Autosorb-1 from Quanta crome. BET surface area (SBET) values were calculated using the model of Brunauer, Emmet and Teller (BET), and the mean crystallite size of the nanoparticles (dp) was estimated by applying Scherrer's equation to the main diffraction peak using a X^' Pert PRO MPD X-ray diffractometer (PANalytical, Almelo, Netherlands) with Cu Ka radiation operating at 60 kV and 40 mA with a Θ/2Θ goniometer. The solid addition method was used to determine pH_pzc. To determine the amount of VR on the nanoparticle surface, thermogravimetric analyses were conducted with a TGA analyzer (Q50, TA Instruments, Inc., New Castle, DE) by heating the nanoparticles containing VR and the virgin alumina nanoparticles from 303 to 973 K at a rate of 288 K/min. Table 2 lists the specifications and surface properties of the nanoparticles used in this study.

Table 2. Specifications and surface properties of selected adsorbents.

Material SBET (m²/g) dp (nm) pHpzc VR loading - TGA

(wt%)

Virgin alumina 132.2 35 9.9 NA

AI/2VR 8 35 9.3 1 .9

AI/4VR 5 35 8.5 3.6

Virgin silica 1 19.1 7 NA NA

The functionalized nanoparticles were characterized by FT-IR, Panels a and b of Fig. 10 show (a) the FT-R spectra of virgin VR, virgin alumina nanoparticles, AI/2VR and AI/4VR nanoparticles and (b) the difference spectra between AI/4VR and virgin alumina nanoparticles and between AI/4VR and virgin VR. For virgin alumina, AI/2VR and AI/4VR nanoparticles one can easily see the characteristic absorption signals of alumina, particularly around 3400 cm^"1 where there is a big band corresponding to the presence of hydroxyl groups. As expected, this broad band is attributed to bonded hydroxyl groups, isolated OH groups and vibrations of adsorbed water. The big absorption band appears between 00 cm ¹ and 400 cm^"1 corresponds to Al- O-AI vibration, the broadening of this band is believed due to the different vacancies in the octahedral and tetrahedral sites of alumina.

Further, the FT-IR spectrum shows bands in the region of functional groups and the finger print region. In the region of functional groups, three bands are observed at 2926, 2850 and 1600 cm^"1. The first two bands correspond to the region of hydrogen's stretching and are assigned to symmetric and asymmetric stretching vibration of the aliphatic CH₃- and CH₂-groups. The third band, at 1600 cm^"1, corresponds to weak alkene C=C bonding. Adsorbed water molecules also generate absorption around 1600 cm^"1 due to bending of those adsorbed molecules. Also, in the IR region of OH or NH group free stretching, a band centered at 3456 cm^"1 is observed and may corresponds to water adsorption on the sample surface or remaining toluene after the functionalization process. In the finger print region four bands are observed at 1450, 1380, 1020 and 868 cm^"1 corresponding to alkane C-H bending, symmetric (medium) nitro compounds, C-N single bond and meta aromatic out-of-plane (oop) C-H bending, respectively. Bands between 1700 and 1000 cm^"1 suggest the presence of various functional groups in the sample. For the FT-IR spectra of the virgin VR, two bands at 1744 and 1690 cm^"1 are observed; suggesting the presence of carbonyl groups due to the 1.82 wt% of oxygen in the sample according to the elemental analysis. However, in the AI/2VR and AI/4VR samples these bands could not be observed. This could be due to the low amount of VR, which makes it difficult for detecting the carbonyl groups. Fig. 10, panel b shows that incorporating VR onto the surface of alumina nanoparticles produces just small differences in the spectra, especially between 2900 and 3000 cm^"1 which correspond to the stretching of C-H bonds in the VR. Also it is possible to see that C-H stretching signal remains and a strong absorption band between 1100 and 1200 cm^"1, this signal is originated in the spectrum difference due to the narrower signal in AI/4VR compared to virgin alumina spectra probably due to changes in the vacancies in the alumina after deposition of VR. FT-IR results show a high presence of non-polar compounds that have affinity with the non-polar molecules present in the oil-fresh water emulsion. Accordingly, a higher content of VR on the alumina surface is expected to increase the surface affinity to non-polar compounds.

Example 4:

ADSORPTION EXPERIMENTS

Adsorption experiments were conducted at 283, 298, 313 and 328 K using a 50-mL glass beaker. The batch adsorption isotherm experiments were performed at different initial concentrations of oil ranging from 100 to 500 mg/L and an initial NaCI concentration of 500 mg/L. Solutions were prepared by diluting stock emulsions of oil at 500 mg/L and of NaCI at 500 mg/L. A total of 25 mg of nanoparticles was added to each emulsion sample (10 mL). A higher proportion of adsorbent and adsorbate could not be used because the high rates of oil removal made the determination of the adsorption isotherms impossible. Emulsions were stirred at 600 rpm for 2 h to reach adsorption equilibrium. Immediately following adsorption of the oil and salt onto the nanoparticles, absorbance and conductivity were measured. Conductivity was measured with a pH/conductivity meter Horiba D-54 (Horiba Instruments Inc., United States). Absorbance was measured using a UV-vis spectrophotometer (Thermo scientific, Waltham, MA) at the same wavelength used in the leaching test. The amount of adsorbed oil or salt " q ", in terms of mg of adsorbate/g of nanoparticles, was determined from the material balance q = (C₀ - C_E)- V /W where C₀ is the initial concentration of the adsorbate in the saltwater (mg/L); C_E is the equilibrium concentration of the adsorbate in the supernatant (mg/L); v is the solution volume (L); and W is the amount of dry nanoparticles added to the brine emulsion or the oil in freshwater emulsion (g).

EFFECT OF CONTACT TIME

Time dependent experiments were performed at 298 K and pH of 7 to determine the oil removal rate from the oily emulsion at oil initial concentrations of 100, 300 and 500 mg/L for virgin alumina nanoparticles and functionalized alumina nanoparticles with different loadings of VR. Panels a-c of Fig. 1 show the amount adsorbed as a function of contact time for (a) virgin alumina nanoparticles, (b) AI/2VR and (c) AI/4VR samples. As seen in Fig. 1 , the adsorbed amount of oil increased with time and leveled off after approximately 25 min of shaking. This time-invariant concentration was considered as the equilibrium time for adsorption. However, for the subsequent experiments a 24-h shaking time was considered sufficient to ensure attaining the adsorption equilibrium. Further, adsorption was roughly dependent on the initial concentration of oil and VR loadings. Increasing the initial concentration of oil slows down the adsorption process; while increasing the VR loading on the nanoparticle surface increases the speed of the adsorption process, owing to the increase in surface hydrophobicity. It is worth noting here that this fast adsorption kinetic could be attributed to the good dispersability of nanoparticles and the high availability of external surface area, as the considered alumina nanoparticles are a non-porous material. Thus, it takes a very short time for the oil molecules to be adsorbed due to the absence of intra-particle diffusion that limits the adsorption rate. The same situation is observed in Figure 2 for oil adsorption from saltwater on the selected nanoparticles.

EFFECT OF SOLUTION PH

The solution pH plays a significant role in adsorption as it affects the functional groups present in both oil molecules and nanoparticle surfaces. Adsorption of oil as a function of pH was studied at pH of 4, 7 and 10 and a temperature of 298 K. Adsorption isotherms of oil from fresh and saltwater by three nanoparticles (i.e., virgin alumina, AI/2VR and AI/4VR) for pH values of 4, 7 and 10 are presented in panels a-c of Fig. 3 and Fig. 4, respectively. As seen in both Figs. 3 and 4, oil adsorption is pH dependent and adsorption isotherms exhibited Type III behavior according to the lUPAC. These types of isotherms are characteristic of systems with low affinity between the adsorbate and the adsorbent, which leads the formation of a multilayer of oil on the nanoparticle surface mainly at high concentration. In this study, for virgin alumina, AI/2VR and AI/4VR nanoparticles, the estimated pH_pzc were 9.9, 9.3 and 8.5, respectively, indicating that as the VR loading increased, the pH_pzc value decreased and stable ionic bonds between the hydroxyls and acid compounds on the VR sample could be formed. Accordingly, nanoparticles in a solution with a pH higher than pH_pzc were negatively charged, and nanoparticles in a solution with a pH lower than pH_pzc were positively charged; i.e., the cationic behavior of nanoparticles became stronger as the pH of a solution decreased. It should be noted here that there could be aromatic nitrogen compounds in the VR structure of pyrrolic and pyridinic type and structures having carbonyl groups that can be altered with pH changes according to their acidity constant. Also, based on the high content of asphaltene in the VR (15 wt%), which are considered to be a molecular structures based on one polycyclic aromatic hydrocarbon (PAH) or many cross-linked PAHs with alkyl side chains and heteroatoms incorporated into many of the cyclic structures, functional groups as carboxyl, ketones, aldehydes, benzothiophenes, dibenzothiophenes, naftenobenzotiophenes, alkyl sulfides, aryl alkyl sulfides and aryl sulfides may be found. The changes of the possible functional groups present on the VR as the system pH is changed could result in the modification of the nanoparticles pHpzc. Thus, the amount of oil adsorbed at pH values lower than pH_pzc increased because the nanoparticles have less cationic behavior. For the three materials, the highest amount adsorbed was found at pH 7 and the lowest at pH 10. Accordingly, one would anticipate that reducing the point of zero charge of the nanoparticle surface would favor the adsorption of oil.

EFFECT OF VR LOADINGS

The effect of VR content on the oil adsorptive removal was determined at 298 K. Panels a-c of Fig. 5 show the adsorption isotherms of oil from freshwater on virgin alumina nanoparticles and alumina functionalized with 2 wt% and 4 wt% VR at (a) pH 4, (b) pH 7 and (c) pH 10. Clearly, adsorption increased as the amount of VR loading on nanoparticle surface increased. This indicates that increasing the VR on the alumina surface favors the affinity of the nanoparticles to the non-polar compounds in the emulsioned water. The oil adsorption process onto the virgin alumina nanoparticles and rapidly adsorption rate is due to the small particle size and the non-porous structure, where there is no intraparticle diffusion and the external adsorption was enhanced. When the VR is loaded onto the alumina surface, besides the synergistic effect with the support, the enhanced adsorption capacity could be explained due aromatic compounds present on the VR that lead to ττ-π interactions with the aromatics present in the oil spills. As seen, clearly the isotherm curves shift to the left upon incorporating VR into alumina surfaces, indicating that the amount of oil adsorbed increased as the VR molecules anchored into nanoalumina surfaces. This is not surprising, as the presence of VR on the nanoparticle surface would increase the surface hydrophobicity and, subsequently, the affinity toward oil molecules. These results also re-affirm that a synergistic effect is achieved upon attaching VR molecules onto the alumina nanoparticle surface. This synergism plays an important role in the overall oil spill sequestration.

EFFECT OF THE TEMPERATURE

The effect of the temperature on the oil adsorptive removal was evaluated at different temperatures of 283, 298, 313 and 328 K. Solution pH was set at 7.0. Panels a-c of Figs. 6 and 7 show the adsorption isotherms of oil from fresh and saltwater, respectively, on virgin alumina, AI/2VR and AI/4VR at different temperatures. For the three nanoparticles, the amount adsorbed decreased as the solution temperature increased. This suggests that temperature has an impact on the interactions forces, and the adsorption is exothermic. Further, temperature can impact the size of oil droplet in the o/w emulsion and subsequently impact the spatial disposition of other oil droplets onto adsorbent surface.

EFFECT OF NaCI

Na⁺ and CI^" can compete with oil molecules and interfere with the adsorption efficiency. Therefore, the effect of NaCI on oil removal was studied for different initial concentrations of oil and a fixed initial concentration of NaCI of 500 mg/L at pH values of 4, 7 and 10. The amount of NaCI adsorbed onto the nanoparticle surface was independent of the initial oil concentration, but highly dependent on the solution pH. Fig. 8 shows the amount of NaCI adsorbed onto alumina, AI/2VR and AI/4VR at pH values of 4, 7 and 10 and an initial NaCI concentration of 500 mg/L. The amount of NaCI adsorbed also increased as the amount of VR on the alumina surface increased. For virgin alumina and AI/2VR, the adsorbed amount of NaCI increased as the solution pH decreased. However, for AI/4VR, the amount adsorbed was similar at pH values of 4 and 10, with the highest occurring at a pH of 7. The amount of NaCI adsorbed was always significantly lower than the amount of oil adsorbed, which shows that the presence of NaCI does not impact the adsorption capacity of the nanoparticles.

EFFECT OF SUPPORT

Virgin alumina and silica nanoparticles were compared for crude oil adsorption. Fig. 9 shows the oil adsorption isotherms onto virgin alumina and silica nanoparticles at 298 K and a pH of 7. Both materials exhibited Type III behavior. Clearly, the alumina nanoparticles had a greater affinity toward the crude oil than the silica nanoparticles. For instance, at equilibrium concentration of 15 mg/L the amount of alumina nanoparticles adsorbed was 13 mg/g, whereas the silica did not show any uptake of oil. EXAMPLE 5:

THE ADSORPTION AND SUBSEQUENT STEAM CATALYTIC CRACKING OF OIL TECHNOLOGY (ASSCCOT)

ASSCCOT is a highly efficient system and process for cleaning of wastewater from the petroleum industry. Figure 11 shows a scheme of ASSCCOT. The system (10) has at least two columns, for example a first column (11 ) and a second column (12). The system also has at least two column positions C1 for water cleaning based on the adsorptive removal of oil, particularly using functionalized alumina nanoparticles, and C2 for the regeneration of the adsorbent and steam catalytic cracking of the adsorbed oil to generate syngas (exiting at 15). This system allows cleaning the water in a continuous flow by operating the at least two columns between the at least two column positions. For this purpose, a first column 11 is charged with functionalized adsorbent and positioned at C1 , oily water enters C1 at inlet 13 (with column 11 functioning as the adsorption column) at a desired inlet hydraulic loading (1.4-6.8 LJm².s) from bottom to top and at desired pressure and temperature, preferably atmospheric pressure and temperatures lower than 673 K. The amount of oil remaining in the water as it passes through the column at C1 will be monitored continually at the column outlet (14). When the adsorbent in the column at C1 is saturated, the column (11 ) swings to the regeneration process position C2 which is set up for oil removal. Column 11 at the regeneration position C2 will operate at selected temperature (lower than 673 K, e.g., 523 to 673K) in order to perform catalytic decomposition of the crude oil adsorbed. The decomposition is instituted by injecting hot steam into the column at the regenerating position C2, for example via heat source 18 resulting in generation of syngas. During adsorbent regeneration, syngas (at outlet 15) is generated and can optionally be used for feeding (via conduit 16) the heat source (18) or generated as a by-product of the process. When Column 11 swings into the C2 position, column 12 charged with functionalized adsorbent swings into the C1 position to receive oily water from inlet 13. When column 12 adsorbent is saturated and when the regeneration of column 11 is finished, the columns swing again between the two positions, so that column 12 is subjected to regeneration at C2 and regenerated adsorbent in column 11 to C1 to again receive oily water. In the swing step, the clean water coming out of the column at C1 (14) is optionally used to cool the regenerating column at C2 until reaching the desired temperature for the adsorption process. Simultaneously, this water is heated by contact with the column at C2 in the cooling process and as heat exchanger is used for inducing heat in the new regeneration column. The process is repeated with the at least two columns switching between C1 and C2 for any selected time, for example for the useful lifetime of the adsorbent. A given system can be implemented with additional columns, e.g., a third and a fourth, etc., swinging between positions C1 and C2. It will also be appreciated that a given system can be implemented with multiple C1 and C2 positions. A given system may have the same or different number of C1 and C2 positions.

Additionally, the ASSCCOT technology can optionally be implemented as ASSTCCOT (Adsorption and Subsequent Steam Catalytic Cracking of Oil Technology) by submitting the swing process to an inert atmosphere (e.g., N₂) in order to obtain condensable hydrocarbons as the product of the regeneration process.

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Removal Procion Dye. International Journal of Environmental Science and Development 2013, 4, (3), 336-340.

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Magnetic Nanoparticles, Anal. Chem. 2008, 80, 5425-5432

Claims

THE CLAIMS

I . A method for removing oil from water contaminated with oil which comprises contacting the contaminated water with nanoparticles comprising alumina wherein the nanoparticles are functionalized by contact with petroleum distillation residue.

2. The method of claim 1 wherein the petroleum distillation residue is petroleum vacuum distillation residue.

3. The method of claim 1 or 2 wherein the nanoparticles are functionalized alumina nanoparticles.

4. The method of claim 1 or 2 wherein the nanoparticles are magnetic nanoparticles comprising alumina.

5. The method of any one of claims 1 -4 wherein the contaminated water is fresh water.

6. The method of any one of claims 1 -4 wherein the contaminated water is sea water.

7. The method of any one of claims 1 -4 wherein the contaminated water is generated by an oil extraction process.

8. The method of any one of claims 1 -7 wherein the contaminated water has pH of 7 or less.

9. The method of any one of claims 1 -7 wherein the contaminated water has pH of 4 to 7.

10. The method of any one of claims 1 -7 wherein the contaminated water has pH of 10 or less.

I I . The method of any one of claims 1 -7 further comprising a step of adjusting the pH of the contaminated water to a pH of 4 to 7.

12. The method of any one of claims 1 -7 further comprising a step of measuring the pH of the contaminated water and adjusting the pH of the contaminated water to a pH of 4 to 7 if necessary.

13. The method of any one of claims 1 -12 wherein the temperature of the contaminated water during contact with the functionalized nanoparticles ranges from 273 K to 325K.

14. The method of any one of claims 1 -13 wherein the functionalized nanoparticles are functionalized with 1 -5 wt% of components of petroleum distillate residue.

15. The method of any one of claims 1 -13 wherein the functionalized nanoparticles are functionalized with 2 to 4 wt% of components of petroleum distillate residue.

16. The method of any one of claims 1 -15 wherein functionalized nanoparticles used for oil adsorption are regenerated by removal of adsorbed oil.

17. The method of claim 16 wherein the used functionalized nanoparticles are treated with stream to at least in part remove adsorbed oil.

18. The method of claim 17 wherein treatment of used functionalized nanoparticles with stream is conducted in the presence of oxygen and syngas is generated.

19. The method of claim 17 wherein treatment of used functionalized nanoparticles with stream is conducted in an inert atmosphere and condensable hydrocarbons are generated.

20. The method of claim 16 wherein the used functionalized nanoparticles are treated with organic solvent to at least in part remove adsorbed oil.

21. The method of any one of claims 16-20 wherein functionalized nanoparticles are provided in at least one column and contaminated water is passed through the at least one column for a selected time and thereafter the at least one column containing used functionalized nanoparticles is subjected to injected steam to provide reusable nanoparticles.

22 A nanoparticle comprising alumina which is functionalized to contain from 1 -5 wt% of components of petroleum distillate residue.

23. The functionalized nanoparticle of claim 22 wherein the petroleum distillate residue is petroleum vacuum distillate residue.

24. The functionalized nanoparticle of claim 22 consisting of alumina.

25. The functionalized nanoparticle of any one of claims 22-24 which comprises components of petroleum distillate residue in addition to asphaltene.

26. The functionalized nanoparticle of claim 22 or 23 which is a core/shell nanoparticle.

27. The functionalized nanoparticle of claim 22 or 23 which is a core/shell nanoparticle wherein the core of the nanoparticle contains magnetic material.

28. The functionalized nanoparticle of claim 22 or 23 which is a core/shell nanoparticle wherein the core of the nanoparticle contains alumina.

29. The functionalized nanoparticle of claim 22 or 23 which is a core/shell nanoparticle wherein the core is magnetic iron oxide coated with silica and the shell is alumina.

30. A method for functionalizing a nanoparticle to enhance adsorption of oil which comprises contacting the nanoparticle with a petroleum distillate residue.

31. The method of claim 30 wherein the nanoparticle comprises alumina.

32. The method of claim 30 wherein the nanoparticle consists of alumina, silica and magnetic iron oxide.

33. The method of claim 30 wherein the nanoparticle consists of alumina and magnetic iron oxide.

34. The method of any one of claims 30-33 wherein the petroleum distillate residue is a petroleum vacuum distillate residue.

35. The method of any one of claims 30-34 wherein the nanoparticle is contacted with a solution of a petroleum distillate residue in a non-polar organic solvent.

36. The method of claim 35 where the non-polar organic solvent is cyclohexane, toluene or xylene.

37. The method of claim 35 or 36 wherein the solution of a petroleum distillate contains residue in the amount of 1 -5wt% with respect to the weight of nanoparticles to be treated.

38. The method of any one of claims 30-37 wherein the contacting is carried out for at least one day.

39. The method of any one of claims 30-37 wherein the contacting is carried out for at least one week.

40. The method of any one of claims 30-39 wherein the contacting is carried out between about 280 K to 310 K.

41. The method of any one of claims 30-40 further comprising washing the contacted nanoparticle with a non-polar organic solvent which does not absorb in the UV-vis until the wash solvent exhibits no UV-vis absorption.