Invention for Separation of oil-water mixtures by nanotechnology

Invented by Jamie Lead, University of South Carolina

The separation of oil and water mixtures is a critical process in many industries, including oil and gas, chemical, and wastewater treatment. Traditional methods of separation, such as gravity settling and filtration, have limitations in terms of efficiency and cost-effectiveness. However, with the advent of nanotechnology, new and innovative solutions have emerged to address these challenges. Nanotechnology involves the manipulation of materials at the nanoscale level, which is typically between 1 and 100 nanometers. This technology has enabled the development of advanced materials and devices that can separate oil and water mixtures more efficiently and effectively than traditional methods. One of the most promising applications of nanotechnology in the separation of oil and water mixtures is the use of nanofibers. Nanofibers are ultrafine fibers with diameters in the range of nanometers. These fibers can be made from a variety of materials, including polymers, ceramics, and metals. Nanofiber-based membranes have been developed for the separation of oil and water mixtures. These membranes have high surface area-to-volume ratios, which allows for efficient separation of oil and water. Additionally, the small pore size of the nanofibers prevents the passage of oil droplets, while allowing water to pass through. Another application of nanotechnology in the separation of oil and water mixtures is the use of nanoparticles. Nanoparticles are tiny particles with diameters in the range of nanometers. These particles can be made from a variety of materials, including metals, ceramics, and polymers. Nanoparticles can be used to create coatings on surfaces that repel oil and attract water. This property is known as superhydrophilicity. When a surface is superhydrophilic, water spreads out evenly across the surface, while oil beads up and rolls off. This property can be used to separate oil and water mixtures by allowing the water to pass through while retaining the oil. The market for the separation of oil and water mixtures by nanotechnology is growing rapidly. The demand for efficient and cost-effective separation methods is driving the development of new and innovative solutions. The oil and gas industry is one of the largest markets for these technologies, as the separation of oil and water is a critical process in the production and refining of oil. Other industries, such as chemical and wastewater treatment, are also adopting nanotechnology-based separation methods. The use of nanofiber-based membranes and nanoparticle coatings is expected to increase in these industries as the technology becomes more widely available and cost-effective. In conclusion, nanotechnology is revolutionizing the separation of oil and water mixtures. The development of advanced materials and devices is enabling more efficient and cost-effective separation methods. The market for these technologies is growing rapidly, driven by the demand for innovative solutions in industries such as oil and gas, chemical, and wastewater treatment.

The University of South Carolina invention works as follows

Methods are provided for extracting oil out of a multiphasic fluid. The method may include introducing a multiphasic fluid to a number of nanoparticles and allowing the oil within the multiphasic to be absorbed by the polymeric layer. Nanoparticles consist of a core and polymeric shell. The method may also include removing the particles from the liquid and/or recovering oil adsorbed on the polymeric surface after removing them from the liquid. The multiphasic fluid can include oil and water (e.g. oil and seawater, such as in the case of an oil spill), stomach liquid and food-grade oils (e.g. olive oil, vegetable or canola oil or a combination thereof), or any other multiphasics liquids that contain an oil component.

Background for Separation of oil-water mixtures by nanotechnology

Recent catastrophic oil spills such as the Deepwater Horizon (2010), 210,000,000 gallons, first Gulf War 1990, 420,000,000 gallons, Exxon Valdez 1989, 11,000,000 gallons, and IXTOC 1 1979, 140,000,000 gallons, are major environmental hazards. The marine ecosystem has been severely damaged by dead seabirds, otters and sea turtles, as well as contaminated planktons and corals. Pollution is also caused by oil spills in bilge waters, from repairs to facilities, and the daily operation. Fracking waste water is another potential environmental threat. Natural gas is often extracted from shale deposits using modern extraction techniques such as directional drilling or hydraulic fracking. Hydrocarbon-mixed water used in shale gas extraction has a significant impact on the contamination level of nearby wells and underground aquifers. Oil contamination of the food chain can have a long-term negative impact. Rapid removal of oil from water surfaces is essential to mitigate the damaging environmental effects of oil spills that spread quickly. To achieve this, different oil spill cleanup methods have been employed, including physical sorption using porous sorbents and skimmers; in situ burning; dispersant-mediated physical diffusion; and biodegradation. The existing methods of cleanup are challenged by the fluidity of the oil in the ocean water, costs, and the time. Moreover, methods such as the floating booms and dispersants made of non-renewable material are more harmful to the environment. “These limitations have inspired recent scientific efforts to develop new nanomaterials that are more efficient at removing oil.

Magnetic nanocomposites, for example, were developed to overcome the difficulties in collecting conventional activated-carbon adsorbents. For enhanced selectivity, polysiloxane-coated Fe2O3@C nanoparticles with a core-shell were used. Recently reported iron oxide-collagen composites used collagen from industrial wastes as an oil absorbent agent, while the iron oxide core was used to provide magnetic actuation. Calcagnile et. al. incorporated weakly bound iron oxide NPs into a polyurethane foam modified with a hydrophobic polytetrafluoroethylene surface to facilitate oil absorption. Magnetite nanofillers in natural rubber with low epoxidation showed high oil absorption. Iron oxide nanoparticles in a biopolymer alky resin with a high concentration increased oil absorption. These studies demonstrate the potential for iron oxide NPs to remove oil. It is especially attractive because iron dioxide NPs have been widely used for bio-applications. They are also known to be low in toxicity due to their chemically stable oxide coat.

However most studies were based upon homogenous oil samples, and the hydrophobic material would not be suitable for submerged oil as they are toxic. To overcome these limitations, polyacrylic-polystyrene-co-polymer encapsulated amphiphilic ferr oxide nanoparticles have been developed for the treatment of crude oils. In most of these studies, iron oxide NPs were synthesized at high temperatures and without air, requiring expensive, complex and environmentally burdensome protocols. To make the hydrophobic NPs more biocompatible, additional ligand-exchange steps were needed.

To minimize environmental impact and to facilitate a simple scale-up of oil remediation applications it is necessary to generate directly stable, water-soluble iron oxide nanoparticles.

The following description will include the main features and benefits of the invention. These may also be evident from the description or can be discovered by using the invention.

Methods for extracting oil are provided in general to remove oil from multiphasic fluids. In one embodiment, a method is provided that involves introducing a multiphasic fluid to a plurality nanoparticles and allowing the oil within the multiphasic to be absorbed by the polymeric layer. The nanoparticles generally have a polymeric core and a shell. In certain embodiments, the method also includes removing the particles from the liquid multiphasic (e.g. using a magnetic force or flowing through a filtration device). The method may also include, in certain embodiments of the invention, recovering the oil adsorbed on the polymeric surface after removing the particles from the liquid.

In one embodiment, the multiphasic fluid is introduced to a number of nanoparticles by flowing it through a cartridge that contains the nanoparticles.

The multiphase liquid can be a combination of oil and water (e.g. oil and seawater, as in the case of an oil spill), stomach liquid and food-grade oils (e.g. olive oil, vegetable or canola oil or a mix thereof), or any other multiphase liquid containing an oil component.

Below, we discuss in more detail the other features and aspects of this invention.

Reference will now be made to embodiments of the present invention, of which one or more examples are given below. Each example is given to explain the invention and not as a limitation. It will be obvious to those of skill in the art that the invention can be modified and varied without departing from its scope or spirit. Features that are illustrated or described in one embodiment may be applied to another embodiment, resulting in a new embodiment. The present invention is intended to cover all modifications and variations that fall within the scope and equivalents of the appended claim. The present discussion should be understood by a person of ordinary skill to the art as only describing exemplary embodiments, and not intended to limit the broader aspects, which are embodied in exemplary constructions.

Methods for quantitatively removing oil from multiphasic fluids (e.g. an oil-water mix) are provided in general.” This application could be used to recover oil after spills or discharges, and remove oils from other liquids such as water. The application is suitable for removing edible oils from gastrointestinal fluids. The oil can be recovered later. “There are also methods for forming nanoparticles which are designed to remove oil quantitatively from oil-water mixes.

These methods, which are aimed at oil removal and not oil dispersion and have the potential to recover oil, use low-toxicity nanomaterials, which can be produced through an easy, inexpensive synthesis process that requires low inputs of energy and materials. The disclosed methods are effective at oil concentrations that correspond to spills and under conditions such as seawater salinity, or the presence of organic macromolecules like humic substances. In certain embodiments, the disclosed methods can remove nearly 100% of the oil within 40-60 mins after contact with the mixture. The methods are also resistant to environmental changes due to oxidation and sulfidation.

The nanoparticles in general are formed by a polymeric core and a shell. Each of these is discussed below. Referring to FIG. In FIG. The nanoparticle 10 is shown as a sphere, but it can be any shape that suits the application (e.g. nanoflake or nanorod .).

I. Nanoparticle core

The methods disclosed here can be used on different types of cores for nanoparticles. The nanoparticle can be made up of, for instance, natural or artificial nanoclays, inorganic metal oxidations, nanolatexes or organic nanoparticles. Inorganic nanoparticles such as iron oxides, silicas, aluminas, titanium oxides, indium-tin oxides (ITO), or CdSe are particularly suitable for nanoparticle cores. Organic nanoparticles that are suitable include polymer, graphite or graphene nanoparticles.

In one embodiment, the nanoparticle core is a core-shell particle. The nanoparticle core, for example, can consist of a core made of a first material (e.g. an Au core) and a shell made of a different metal (e.g. a silvershell).

In one embodiment, the core of the nanoparticle can be made up of a metal oxide. Examples include iron oxides (e.g. alumina), silicas, aluminum oxides (e.g. alumina), copper oxides, zinc oxides indium tin oxidations, titanium oxides, nickel oxides and cobalt oxides. These metal oxides may be any combination of metal, oxygen and an optional element (e.g. another metal). For example, suitable iron oxides can include iron(II) oxide (FeO), iron(II,III) oxide (Fe3O4 or Fe4O5), iron(III) oxide (Fe2O3), etc. Similarly, suitable titanium oxides can include titanium dioxide (TiO2), titanium(II) oxide (TiO), titanium(III) oxide (Ti2O3), etc. Copper oxides that are suitable include cupric oxide (CuO), cuprous oxide (Cu2O), and others.

The core of the coated nanoparticle can be made from iron oxide nanoparticles that are primarily formed by maghemite and magnetite. These iron oxide cores can have superparamagnetic characteristics (also known as SPIONs), which are particularly suitable for some embodiments.

In one particular embodiment, the core can be magnetic (e.g., a magnetite iron oxide core) to allow for separation/removal/extraction of the nanoparticle from the multiphasic liquid utilizing a magnetic force. Other magnetic materials, such as cobalt oxides or nickel oxides can also be used.

In certain embodiments, the core can have an average size of 100 nm, or less. For example, it could be between 15 nm and 50 nm. This small size ensures a large surface area of the polymer shell, which is necessary to achieve sufficient oil absorption.

The core can be made up of a single nanoparticle or an agglomeration/aggregation of nanoparticles. The core can have a diameter of 15 nm or 50 nm if only a few nanoparticles are used (e.g. 1 to 10 nanoparticles), but it can also be larger if the core is made up of a large agglomeration (e.g. a core of 50 nm-500 nm from a number of nanoparticles). Oil and high-ionic strength solutions can increase agglomeration. The core can also be composed of particles (single or multiple crystals), agglomerates (weakly or strongly bound), or a single crystal.

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