Filter aid for treating oil and method of making and use thereof

Abstract

To provide compositions and methods for filtering oil, e.g., for removing free fatty acids (FFAs) from an oil used for cooking.SOLUTION: A composition may comprise a filter aid that includes an alkali silicate, and a composite material comprising a silicate mineral at least partially coated with an inorganic silica or silicate. The filter aid includes an alkali silicate, and a silicate mineral, wherein at least a portion of the alkali silicate is present as a coating on the silicate mineral, and wherein a ratio of the alkali silicate to silicate mineral in the filter aid ranges from about 1:4 to 4:1 by weight. The filter aid further includes an alkali silicate, a silicate mineral, and an adsorbent. A method of filtering an oil may include combining the oil with the filter aid, optionally heating the mixture, and separating at least a portion of the filter aid from the oil to thereby remove at least a portion of the FFAs from the oil.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Priority claim This PCT international application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 598,728, filed December 14, 2017, the subject matter of which is incorporated herein by reference in its entirety.

[0002] Embodiments of the present disclosure generally relate to compositions useful as filter aids, for example, for filtering oil. The compositions may include a filter aid comprising a composite silicate material and an alkali silicate. [Background technology]

[0003] The use of cooking oils to fry foods can result in several forms of oil contamination, for example, by hydrolysis, oxidation, and / or polymerization. During cooking, moisture present in food turns into steam, which, together with oxygen, can initiate chemical reactions to produce free fatty acids (FFA). An example of the mechanism by which FFAs are produced from triglycerides is shown below: [ka]

[0004] The amount of FFA in cooking oils tends to increase with use (repeated frying). FFAs have a negative effect on the quality of the oil, for example, reducing the oxidative stability of the oil and / or causing off-flavors in food. Therefore, the FFA content can provide an indicator of the quality of the oil. Therefore, compositions and methods that can reduce the FFA content of cooking oils may be of interest. Summary of the Invention

[0005] The present disclosure includes filter aids, methods for using the same, and methods for making the same. For example, in one example, the present disclosure includes a filter aid comprising (a) an alkali silicate and (b) a composite material comprising a silicate mineral at least partially coated with inorganic silica or silicate. In another example, the present disclosure includes a filter aid comprising (a) an alkali silicate and (b) a silicate mineral, wherein at least a portion of the alkali silicate is present as a coating on the silicate mineral, and the ratio of the alkali silicate to the silicate mineral in the filter aid ranges from about 1:4 to 4:1 by weight. In yet another example, the present disclosure includes a filter aid comprising an alkali silicate, a silicate mineral, and an adsorbent.

[0006] In one example, the present disclosure provides a filter aid comprising an alkali silicate and a composite material comprising a silicate mineral at least partially coated with inorganic silica or silicate. The alkali silicate may include, for example, sodium silicate, potassium silicate, or a mixture thereof. In some examples, the alkali silicate may include sodium metasilicate, such as sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, anhydrous sodium metasilicate, or a mixture thereof. For example, the filter aid may include about 10% to about 75% by weight of sodium metasilicate pentahydrate.

[0007] In one example, the filter aid comprises about 10% to about 70% by weight of alkali silicate. In another example, the filter aid comprises about 10% to about 60% by weight of alkali silicate, about 10% to about 60% by weight of silicate mineral, and about 10% to about 60% by weight of adsorbent.

[0008] Additionally or alternatively, the silicate mineral of the filter aid may include biogenic silica (e.g., diatomaceous earth), perlite, pumice, pumice powder, obsidian, tallow, volcanic ash, or a combination thereof. Furthermore, for example, the inorganic silica or silicate may include silica gel, sodium silicate, magnesium silicate, or a combination thereof. In at least one example, the inorganic silica or silicate is precipitated on the surface of the silicate mineral. According to some examples herein, the filter aid composite comprises about 50 wt% to about 95 wt% biogenic silica and / or about 5 wt% to about 80 wt% inorganic silica or silicate, based on the total weight of the composite. In some examples, the alkali silicate may be present as loose particles, e.g., a powder, which are mixed with the composite to form the filter aid. In some examples, the alkali silicate may comprise a compound or mixture of compounds different from the inorganic silica or silicate of the composite.

[0009] In one example, the filter aid may include at least one adsorbent. In some examples, the adsorbent may be at least partially coated on the silicate mineral. In other examples, the adsorbent may be a granular material that is not substantially bound to the silicate mineral. In many examples, the adsorbent may be magnesium silicate.

[0010] The filter aid may have a permeability in the range of about 0.05 darcy to about 10.0 darcy and / or a permeability of about 0.2 m 2 / g ~ approx. 450m 2 / g。 In some examples, the particle size distribution of the composite material in the filter aid may be in the range of about 5 μm to about 300 μm. 50 Further, in some examples, the filter aid may have a bimodal particle size distribution. In some examples, the composite material has a median pore size (4V / A) ranging from about 0.1 μm to about 10.0 μm and / or a particle size distribution of about 5 lb / ft. 3 ~30lb / ft 3 In at least one example, the filter aid comprises about 0.5% to about 10% water by weight, based on the total weight of the filter aid.

[0011] Further included herein are compositions containing the filter aids described above and elsewhere herein. For example, the compositions may contain at least 80% by weight of the filter aid and about 1.0% to about 10.0% by weight of water, based on the total weight of the composition. In some examples, the composition (e.g., an aqueous composition) has a pH ranging from about 9.0 to about 13.0. In some examples, the composition is in the form of a dry granule. In another example, the filter aid contains about 0.5% to about 20% by weight of water, for example, about 1% to about 10% by weight of water, based on the total weight of the filter aid.

[0012] The present disclosure also includes a method for filtering oil using such a filter aid and / or composition. For example, the method can include mixing oil with a filter aid to form a mixture, where the filter aid includes an alkali silicate and a composite material including a silicate mineral at least partially coated with inorganic silica or silicate. As described above, the alkali silicate can include sodium silicate, potassium silicate, or a mixture thereof. For example, the filter aid can include sodium metasilicate, such as sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, anhydrous sodium metasilicate, or a mixture thereof.

[0013] According to some embodiments of the present disclosure, the filtration method further comprises heating a mixture containing oil and a filter aid. The oil may contain free fatty acids, for example, about 0.05% to about 10.0% by weight of free fatty acids. The method may further comprise separating at least a portion of the filter aid from the oil, wherein the filter aid removes at least 50%, at least 65%, or at least 70% by weight of the free fatty acids from the oil. The oil may comprise an edible oil, such as an oil derived from an animal or / and a plant. In some examples, the mixture comprises about 0.05% to about 10.0% of the filter aid based on the weight of the oil.

[0014] The present disclosure also includes methods for making such filter aids. For example, the method may include preparing a composite material by at least partially coating a silicate mineral with inorganic silica or silicate and combining the composite material with an alkali silicate. The alkali silicate may include sodium silicate, potassium silicate, or a mixture thereof. For example, the alkali silicate may include sodium metasilicate, such as sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, anhydrous sodium metasilicate, or a mixture thereof. Additionally or alternatively, the silicate mineral may include diatomaceous earth, and preparing the composite material includes precipitating the inorganic silica or silicate on the surface of the diatomaceous earth. In at least one example, the method further includes adding water to the filter aid so that the filter aid contains about 0.5 wt. % to about 10 wt. % water based on the total weight of the filter aid.

[0015] In another example, the method for producing the filter aid comprises coating an alkali silicate on a silicate mineral substrate. In one example, the coating can be achieved using a rotary mixer or a pan pelletizer. In another example, the coating can be achieved using a spray drying process. In some examples, the method for producing the filter aid can comprise mixing an adsorbent with an alkali silicate and a silicate mineral. DETAILED DESCRIPTION OF THE INVENTION

[0016] Certain aspects of the present disclosure are described in more detail below. In the event of a conflict with terms and / or definitions incorporated herein by reference, the terms and definitions set forth herein shall control.

[0017] As used herein, the terms "comprises," "comprising," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, composition, article, or device that includes a list of elements does not include only those elements, but may also include other elements not expressly listed in or inherent to such process, method, composition, article, or device. The term "exemplary" is used in the sense of "example" rather than "ideal."

[0018] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context dictates otherwise. The terms "approximately" and "about" refer to being nearly the same as a referenced number or value. As used herein, the terms "approximately" and "about" should be understood to include ±5% of the specific amount or value.

[0019] The present disclosure includes filter aids useful for filtering oils, such as edible oils or other oils used for cooking or frying, to remove contaminants such as FFAs. The filter aids herein may include at least one silica or silicate, or a combination of multiple types of silica / silicates, which may be biogenic or inorganic.

[0020] In some examples herein, the filter aid comprises a silicate mineral at least partially or completely coated with silica or a silicate, and the substrate optionally comprises a silicate material different from the coating, such that a composite is formed. The coated silicate mineral can be further combined with another silicate compound, such as an alkali silicate, e.g., a sodium silicate such as sodium metasilicate.

[0021] In another example, the filter aid comprises a silicate mineral coated with an alkali silicate, such as sodium silicate-coated diatomite or sodium silicate-coated perlite. For example, the filter aid can comprise an alkali silicate and a silicate mineral, wherein at least a portion of the alkali silicate is present as a coating on the silicate mineral, and the ratio of the alkali silicate to the silicate mineral in the filter aid ranges from about 1:4 to 4:1 by weight.

[0022] In another example, the filter aid comprises an alkali silicate, a silicate mineral, and an adsorbent. The adsorbent can be, for example, an alkaline earth metal silicate, such as magnesium silicate.

[0023] Without intending to be bound by theory, it is believed that the combination of silicates of filter aids can provide a functional synergy, for example, by filtering oil, maintaining or improving the quality of oil used in cooking, for example, frying oil.In some examples, filtering can include mixing oil with filter aids to form a mixture.Such filtering can neutralize FFAs with the alkali silicate (e.g., sodium silicate) of the filter aid, forming salts, thereby enabling the removal of FFAs: [ka]

[0024] FFA salts (commonly referred to as soaps) can be adsorbed onto the coated silicate mineral particles of the filter aid, e.g., the FFA salts can be physically and / or chemically attached to the coated silicate mineral particles, allowing for removal of the FFAs by filtering the particles from the oil.

[0025] According to some aspects of the present disclosure, the filter aid comprises an alkali silicate, such as sodium silicate, potassium silicate, or a mixture thereof. For example, the filter aid may comprise sodium silicate (Na2SiO2) nThe alkali silicate may include sodium metasilicate (NaSiO) having a molar ratio of SiO:NaO ranging from 1.0 to 4.0. The alkali silicate may be hydrated or anhydrous. In some examples, the sodium silicate includes sodium metasilicate (NaSiO) having a molar ratio of SiO:NaO of 1.0. For example, the filter aid may include anhydrous sodium metasilicate and / or a hydrated form of sodium metasilicate, such as sodium metasilicate pentahydrate (NaSiO·5H2O), sodium metasilicate nonahydrate (NaSiO·9H2O), any other hydrated form, or a mixture thereof. In at least one example, the sodium silicate includes sodium metasilicate pentahydrate. In at least one example, the sodium silicate includes sodium metasilicate nonahydrate.

[0026] In some examples, the alkali silicate may be in powder form, and the filter aid may further comprise a granular material (e.g., silicate mineral particles at least partially or completely coated with silica or silicate), such as a composite material. Therefore, at least a portion of the alkali silicate may not be attached to the silicate mineral particles or otherwise associated with the coating of the silicate mineral particles; for example, the alkali silicate may be present in the form of free particles. For example, the filter aid may comprise particles having a bimodal distribution (e.g., corresponding to the particle size distribution of the free alkali silicate and the particle size distribution of the composite). Furthermore, for example, the alkali silicate may comprise a compound or mixture of compounds different from the inorganic silica or silicate of the composite. For example, the filter aid may comprise sodium silicate and / or potassium silicate, and the coating of the composite may comprise silica gel. In another example, the coating of the composite may comprise sodium silicate, and the alkali silicate may comprise a different sodium silicate from the coating (e.g., a different hydration form, a different molar ratio of SiO2 / Na2O, anhydrous versus hydrated, etc.).

[0027] In some examples, the filter aid may comprise about 5 wt.% to about 80 wt.%, for example, about 10 wt.% to about 75 wt.%, about 15 wt.% to about 70 wt.%, about 10 wt.% to about 20 wt.%, about 5 wt.% to about 25 wt.%, about 20 wt.% to about 60 wt.%, about 25 wt.% to about 50 wt.%, about 30 wt.% to about 65 wt.%, or about 50 wt.% to about 75 wt.% of the alkali silicate, based on the total weight of the filter aid. Without intending to be bound by theory, it is believed that alkali silicates, such as sodium metasilicate, can provide a combination of base strength and water content that is particularly useful for neutralizing FFAs in oil mixtures.

[0028] The granular composite material of the filter aid may comprise silicate minerals at least partially or completely coated with one or more of silica, silicate, and / or aluminosilicate compounds. According to some embodiments of the present disclosure, silicate minerals include mineral particles containing one or more silicates and / or aluminosilicates, including glassy minerals and materials derived from glassy minerals. Examples of silicates and aluminosilicates include, but are not limited to, diatomaceous earth, perlite, pumice, pumice powder, volcanic ash, calcined kaolin, smectite, mica, shirasu, obsidian, tartar, rice husk ash, and combinations thereof.

[0029] Diatomaceous earth (also known as "DE" or "diatomite") is a type of sediment rich in biogenic silica (silica produced or provided by living organisms), commonly in the form of siliceous frustules of diatoms. Diatoms are a diverse group of microscopic, unicellular, golden-yellow algae, generally of the class Diatomaceae, that possess diverse and complex ornate siliceous skeletons with two shells that interlock like pillboxes in living diatoms. Diatomaceous earth can be formed from the remains of aquatic diatoms, and therefore, diatomaceous earth deposits can be found near current or former bodies of water. These deposits are generally divided into two categories, freshwater and saltwater, depending on their source. Freshwater diatomaceous earth is typically mined from dry lake beds and can be characterized by low crystalline silica and high iron content. In contrast, saltwater diatomaceous earth is typically extracted from marine areas and can be characterized by high crystalline silica and low iron content.

[0030] Glassy minerals (which may also be called "volcanic glass") are formed by the rapid cooling of siliceous magma or lava. Volcanic glasses, such as perlite and pumice, tend to occur in large deposits. Volcanic ash (often called "tuff" in its consolidated form) is a form of glass and contains small particles or fragments that may also be characterized as glassy minerals.

[0031] Perlite is a hydrated glassy mineral containing silicon dioxide, aluminum oxide, and a combination of other metals or metal oxides, such as sodium oxide and iron oxide. For example, perlite may contain approximately 70% to 75% by weight SiO, approximately 12% to 15% by weight AlO, approximately 0.5% to 2% by weight FeO, approximately 3% to 5% by weight NaO, approximately 3% to 5% by weight KO, approximately 0.4% to 1.5% by weight CaO, and smaller amounts of other metals or metal oxides. Perlite can be distinguished from other glassy minerals by its relatively high water content (e.g., approximately 2% to 5% by weight), glassy, ​​pearlescent luster, and characteristic concentric or arched onion-skin-like fractures. The Mohs hardness of perlite is typically greater than about 5, e.g., in the range of about 5.5 to about 7.0.

[0032] Expanded perlite refers to perlite that has been heated and undergoes thermal expansion due to the evaporation of its internal water. For example, perlite can be heated rapidly until the glass begins to soften (approximately 750°C to 1100°C), and the water recombines and evaporates. As long as the glass is soft enough to be expanded by water vapor, the water vapor can expand, creating tiny bubbles within the glass matrix, which then breaks down into smaller pieces with sharp edges.

[0033] Pumice is a glassy mineral characterized by a mesoporous structure, e.g., possessing pores or vesicles. Pumice's porosity gives it a relatively low apparent density, often allowing it to float on the surface of water. Pumice typically contains about 60% to about 70% SiO2 by weight. Obsidian material comprises silica-rich glassy minerals. Obsidian glass can be subdivided into subcategories based on silica content, with rhyolite obsidian (typically containing about 73% SiO2 by weight) being the most common. Rice husks contain sufficient silica to be commercially incinerated into siliceous debris, a product commonly known as rice husk ash. Certain sponge bodies are also concentrated sources of silica, the remains of which can be found in geological deposits as acicular spicules.

[0034] According to some aspects of the present disclosure, the silicate mineral comprises a silicate material, such as biogenic silica. In some examples herein, the silicate mineral may comprise diatomaceous earth, perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or a combination thereof. In some examples, the silicate mineral comprises diatomaceous earth. In at least one example, the silicate mineral comprises perlite, such as expanded perlite.

[0035] The silicate mineral may be treated, for example, partially or completely coated with one or more silica, silicate, and / or aluminosilicate compounds. In some examples, the coating comprises inorganic silica and / or silicate. Examples of inorganic silica / silicates that can be used for coating include, but are not limited to, silica gel, sodium silicate, magnesium silicate, and combinations thereof. In at least one example, the inorganic silica / silicate is precipitated on the surface of the silicate mineral. For example, the filter aid herein may comprise inorganic silica / silicate or a mixture of inorganic silica / silicate precipitated on particles (e.g., particles of diatomaceous earth, perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or combinations thereof). In at least one example, the coated silicate mineral comprises diatomaceous earth particles at least partially or completely coated with sodium silicate, magnesium silicate, or a mixture of sodium silicate and magnesium silicate.

[0036] In at least one example, the composite material includes silicate particles (e.g., diatomaceous earth particles) at least partially coated with magnesium silicate, and the alkali silicate includes sodium silicate and / or potassium silicate. In at least one example, the composite material includes silicate particles (e.g., diatomaceous earth particles) at least partially coated with sodium silicate, and the alkali silicate includes a sodium silicate that is different from the sodium silicate of the coating. In yet another example, the composite material includes silicate particles (e.g., diatomaceous earth particles) at least partially coated with silica gel, and the alkali silicate includes a sodium silicate, such as sodium metasilicate.

[0037] In some examples, the silica / silicate coating can comprise about 5% to about 50% by weight of the coated silicate mineral of the composite. For example, the filter aid can include a composite material comprising about 20% to about 95% by weight of mineral particles and about 5% to about 80% by weight of inorganic silica / silicate at least partially or completely coating the mineral particles. In some examples, the composite material includes about 50% to about 95% by weight of biogenic silica (e.g., diatomaceous earth particles) or volcanic glass (e.g., perlite, pumice, pumice powder, obsidian, tartar, or volcanic ash particles) and an inorganic silicate or mixture of inorganic silicates precipitated on the biogenic silica or volcanic glass. In some examples, the composite material comprises about 5% to about 80%, about 10% to about 70%, about 15% to about 50%, or about 25% to about 40% by weight of inorganic silica / silicate or a mixture of inorganic silica / silicate, based on the total weight of the composite material, and the inorganic silica / silicate or mixture of inorganic silica / silicate at least partially coats or completely coats the biogenic silica or volcanic glass particles.

[0038] The substrate mineral particles can be subjected to one or more processing steps, such as milling and / or classification, to achieve the desired particle size distribution before coating. For example, the mineral particles can be milled so that the particles have the desired size distribution. Additionally or alternatively, the mineral particles can be subjected to one or more processing steps after coating. Particle size and other particle size characteristics referred to in this disclosure can be measured by any suitable measurement technique, such as, for example, a Sedigraph 5100 instrument supplied by Micromeritics Corporation or a Microtrac Model X-100 supplied by Leeds & Norththrup. Using such measurement equipment, the size of a given particle is expressed in terms of the diameter of a sphere of equivalent diameter, sometimes referred to as the equivalent spherical diameter, or (ESD). The median particle size, or d 50 The value is d 50 is the diameter with ESD less than the value. 90The value is d 90 is the diameter with ESD less than the value d 10 The value is d 10 The diameter having an ESD less than the value. Other methods and / or devices for determining particle size are also contemplated.

[0039] According to some embodiments of the present disclosure, the silicate mineral or composite material has a median particle size (d) in the range of about 1 μm to about 300 μm, e.g., about 5 μm to about 300 μm, about 100 μm to about 300 μm, about 150 μm to about 300 μm, about 1 μm to about 100 μm, about 5 μm to about 100 μm, about 10 μm to about 100 μm, about 50 μm to about 100 μm, about 1 μm to about 50 μm, about 5 μm to about 50 μm, about 10 μm to about 50 μm, about 1 μm to about 10 μm, about 5 μm to about 10 μm, or about 1 μm to about 5 μm. 50 For example, the composite material has a d value in the range of about 40 μm to about 300 μm, about 40 μm to about 250 μm, about 100 μm to about 250 μm, about 5 μm to about 150 μm, about 40 μm to about 140 μm, about 60 μm to about 120 μm, about 30 μm to about 60 μm, about 60 μm to about 90 μm, about 90 μm to about 120 μm, about 120 μm to about 150 μm, about 1 μm to about 40 μm, about 10 μm to about 40 μm, about 10 μm to about 30 μm, or about 15 μm to about 25 μm. 50 It may have a value.

[0040] Additionally or alternatively, the silicate mineral or composite material may have a diameter ranging from about 50 μm to about 700 μm, e.g., from about 300 μm to about 700 μm, from about 300 μm to about 500 μm, from about 100 μm to about 300 μm, from about 200 μm to about 400 μm, from about 50 μm to about 300 μm, from about 100 μm to about 200 μm, from about 200 μm to about 300 μm, from about 50 μm to about 100 μm, from about 60 μm to about 140 μm, from about 70 μm to about 120 μm, or from about 80 μm to about 110 μm. 90 It may have a value.

[0041] Additionally or alternatively, the silicate mineral or composite material may have a diameter in the range of about 1 μm to about 30 μm, e.g., about 1 μm to about 10 μm, about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 5 μm to about 15 μm, about 15 μm to about 25 μm, about 20 μm to about 25 μm, about 2 μm to about 20 μm, about 3 μm to about 15 μm, about 4 μm to about 12 μm, about 5 μm to about 10 μm, about 1 μm to about 5 μm, or about 1 μm to about 3 μm. 10 It may have a value.

[0042] A silicate mineral or composite material can have a desired pore size or pore size distribution. One technique for showing the pore size distribution in a material is mercury intrusion porosimetry, which uses mercury intrusion under an applied isostatic pressure to measure microscale pores, such as those in silicate minerals. In this method, a material is surrounded by liquid mercury in a sealed vacuum chamber, and the pressure is gradually increased. The chamber is sealed, and the pressure is reduced to a very low level before mercury intrusion begins. At low pressures, the mercury does not penetrate the sample due to the high surface tension of liquid mercury. As the pressure increases, the mercury migrates into the sample, first into the largest spaces, where the curvature of the mercury surface is minimal. As the pressure is further increased, the mercury migrates into the denser spaces of the material. Eventually, all voids are filled with mercury. The nanoporous structure can be measured by nitrogen adsorption using an ASAP™ 2460 Surface Area and Porosimetry Analyzer, available from Micromeritics Instrument Corporation (Norcross, Georgia, USA). In this way, a plot of total pore volume versus pressure can be developed. Therefore, this method can not only provide the total pore volume, but also identify the pore size distribution. Once the pore distribution is estimated, an estimate of the surface area can be calculated by inferring the shape of the pores (which can generally be assumed to be spherical) based on the pore size. An estimate of the median pore size can also be calculated based on the volume or area. The median pore size (volume) is the 50th percentile pore size in the integrated volume graph, and the median pore size (area) is the 50th percentile pore size in the integrated area graph. The average pore size (diameter) is four times the ratio of the total pore volume to the total pore area (4V / A). In some examples, the composite material can have a median pore size (4V / A) in the range of about 0.1 μm to about 10.0 μm, e.g., about 0.1 μm to about 5.0 μm, about 0.5 μm to about 5.0 μm, about 0.1 μm to about 1.0 μm, about 1.0 μm to about 10.0 μm, about 1.0 μm to about 5.0 μm, about 2.0 μm to about 5.0 μm, about 1.5 μm to about 8.0 μm, or about 5.0 μm to about 10.0 μm.

[0043] If the true density remains relatively constant, a filtration component with a lower wet density may result in a product with greater porosity and, therefore, potentially greater filtration efficiency. According to some embodiments, the composite material has a wet density of about 5 lb / ft 3 ~30lb / ft 3 in the range of (approx. 80.1 kg / m 3 ~Approx. 480.6kg / m 3 For example, the composite may have a wet density of about 10 lb / ft 3 ~approx. 20 lb / ft 3 , approximately 20 lb / ft 3 ~30lb / ft 3 , approximately 15 lb / ft 3 ~25lb / ft 3 , about 25lb / ft 3 ~35lb / ft 3 , approximately 15 lb / ft 3 ~approx. 20 lb / ft 3 , approximately 20 lb / ft 3 ~25lb / ft 3 , or about 25 lb / ft 3 ~30lb / ft 3 Since wet density reflects the void volume of the adsorbent component that traps matter during the filtration process, a lower wet density may indicate that the adsorbent component has a higher void volume and is therefore able to adsorb more elements in the fluid.

[0044] Wet density can be measured by placing a sample of known weight (approximately 1.00 g to approximately 2.00 g) in a graduated 15 mL centrifuge tube. Deionized water is then added to bring the volume to approximately 10 mL. The mixture is shaken thoroughly until the sample is completely hydrated and powder-free. Additional deionized water is added near the top of the tube to wash off any mixture that adheres to the sides of the tube after shaking. The tube is then centrifuged at 2500 RPM for 5 minutes in an IEC Centra™ MP-4R centrifuge (International Equipment Company, Needham Heights, Massachusetts, USA) equipped with a Model 221 swinging bucket rotor. After centrifugation, the tube is carefully removed without disturbing the solids, and the extent (volume) of the settled material is measured. The wet density after centrifugation is then calculated by dividing the sample weight by the measured volume, e.g., g / cm. 3 (or kg / m based on the units used during the test) 3 or lb / ft 3 Calculated in units of (e.g.,

[0045] The filter aids herein may have beneficial characteristics for filtering oils and oil mixtures. According to some examples herein, the filter aids may have a thickness of about 0.2 m 2 / g ~ approx. 450m 2 / g, for example, about 5m 2 / g~about 400m 2 / g, approx. 25m 2 / g ~ approx. 250m 2 / g, approx. 50m 2 / g~about 150m 2 / g, about 100m 2 / g~about 200m 2 / g, approx. 75m 2 / g~about 150m 2 / g, approx. 300m 2 / g ~ approx. 450m 2 / g, approx. 250m 2 / g~about 300m 2 / g, about 100m 2 / g~about 150m 2 / g, or approximately 50m 2 / g~about 300m 2 / g.

[0046] According to some examples, the filter aid can have a permeability suitable for use in filtering non-aqueous liquids, such as edible oils, or other oils or oil mixtures used in cooking or useful for cooking.Permeability is generally measured in Darcy units, i.e., Darcy.Permeability can be determined by using a device designed to form a filter cake on a septum from an aqueous suspension of the filter aid composition, and then measuring the time required for a specified volume of water to flow through a measured thickness of a filter cake with a known cross-sectional area.For example, permeability is measured by applying a pressure difference of 1 atmosphere to the filter aid composition, and then measuring the time required for a specified volume of water to flow through a measured thickness of the filter cake with a known cross-sectional area. 3 A fluid with a viscosity of 1 mPa·s flows at a flow rate of 1 / sec through a section of 1 cm high and 1 cm cross-sectional area. 2 The permeability can be measured through porous filter aid materials. The principle of permeability measurement has previously been derived for porous media by Darcy's Law (see, e.g., J. Bear, "The Equation of Motion of a Homogeneous Fluid: Derivations of Darcy's Law," in Dynamics of Fluids in Porous Media 161-177 (2nd ed. 1988)).

[0047] According to some examples, the filter aid may have a permeability ranging from about 0.05 darcy to about 10.0 darcy. For example, the filter aid may have a permeability ranging from about 0.1 darcy to about 10.0 darcy, from about 0.1 darcy to about 5.0 darcy, from about 0.1 darcy to about 3.0 darcy, from about 0.5 darcy to about 2.5 darcy, from about 0.5 darcy to about 1.5 darcy, from about 1.0 darcy to about 2.0 darcy, from about 0.1 darcy to about 1.0 darcy, from about 0.5 darcy to about 1.0 darcy, from about 1.0 darcy to about 2.5 darcy, from about 0.05 darcy to about 1.0 darcy, or from about 0.1 darcy to about 0.5 darcy.

[0048] According to some embodiments of the present disclosure, the filter aid can be provided as a composition such as an aqueous suspension or slurry. In some examples, the composition can include water, e.g., at least 75% or at least 80% by weight, and about 1.0% to about 10.0% by weight of the filter aid. For example, the composition can include about 1.0% to about 5.0% by weight, about 2.5% to about 7.5% by weight, about 5.0% to about 7.5% by weight, about 3.5% to about 8.0% by weight, or about 3.5% to about 6.5% by weight of the filter aid, based on the total weight of the composition. According to some embodiments, the composition includes an aqueous suspension or slurry containing 4.0%, 4.5%, 5.0%, 5.5%, or 6.0% by weight of the filter aid, based on the total weight of the composition. Such aqueous compositions can have a pH in the range of about 9.0 to about 13.0, such as about 10.0 to about 13.0, about 11.0 to about 12.0, or about 12.0 to about 13.0.

[0049] The filter aid herein can be prepared, for example, by preparing a composite material (particulate material) by at least partially coating a silicate mineral with inorganic silica / silicate (e.g., silicate or silica gel) and combining the composite material with an alkali silicate, e.g., sodium metasilicate.

[0050] The preparation of the filter aid composite material can include precipitating inorganic silicate on the surface of silicate mineral, for example, precipitating sodium silicate and / or magnesium silicate on particles of diatomaceous earth, perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or a combination thereof. The precipitated sodium silicate and / or magnesium silicate can form an adsorbent coating or layer that is precipitated in situ on the surface of the substrate mineral particles. In some examples, silicate mineral particles can be coated with silica gel, for example, by mixing the silicate mineral particles with water, sodium silicate, and acid (e.g., H2SO4). The composite material thus formed can retain the adsorption characteristics (e.g., for the formation of FFA salts) of the silicate coating and the filtration properties of the substrate mineral particles.

[0051] In one example, the filter aid may comprise a silicate mineral coated with an alkali silicate, such as diatomite coated with sodium silicate or perlite coated with sodium silicate. In one example, the filter aid comprises an alkali silicate and a silicate mineral, at least a portion of the alkali silicate being present as a coating on the silicate mineral, and the ratio of the alkali silicate to the silicate mineral in the filter aid is in the range of about 1:4 to 4:1 by weight.

[0052] In some examples, the alkali silicate can include, for example, sodium silicate, potassium silicate, or a mixture thereof. For example, the alkali silicate can include sodium metasilicate, such as sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, anhydrous sodium metasilicate, or a mixture thereof. In some examples, the silicate mineral can include biogenic silica (e.g., diatomite), perlite, pumice, pumice powder, obsidian, tallow rock, volcanic ash, or a combination thereof.

[0053] In some examples, the ratio of alkali silicate to silicate mineral in the coating can range from about 1:4 to about 4:1, e.g., from about 1:2 to about 1:4, from about 3:4 to about 1:4, from about 1:1 to about 1:4, from about 1:1 to about 1:3, from about 1:1 to about 1:2, or from about 1:2 to about 2:1.

[0054] In one example, coating can be achieved by using a rotary mixer or pan pelletizer.In another example, coating can be achieved by using a spray-drying process.In some examples, the method for making filter aid can include mixing adsorbent with alkali silicate and silicate mineral.In general, it is considered that the granulation method based on mixing is preferred when the ratio of alkali silicate and silicate mineral in coating is lower, and spray-drying is preferred when the ratio is higher.

[0055] In another example, the filter aid may comprise a combination of alkali silicate, silicate mineral, and adsorbent material. In this example, the silicate mineral filter does not need to be chemically modified or functionally coated. When alkali silicate and silicate mineral are used together with an adsorbent, the resulting filter aid can provide a good balance between free fatty acid removal, soap removal, filtration rate, and cost, even if the adsorbent itself has a relatively low filtration efficiency.

[0056] In one example, the sorbent can be at least partially coated on the silicate mineral. In another example, the sorbent can be a particulate material that is substantially unbound to the silicate mineral. In some examples, the sorbent can include an alkaline earth metal silicate, such as magnesium silicate.

[0057] In some examples, the filter aid comprises about 10% to about 60% by weight of alkali silicate, about 10% to about 60% by weight of silicate mineral, and about 10% to about 60% by weight of adsorbent. For example, the filter aid may comprise 10% to about 50% by weight, such as about 20% to about 50%, about 30% to about 60%, or about 30% to about 50% of alkali silicate. Also, for example, the filter aid may comprise 10% to about 50% by weight, such as about 20% to about 50%, about 30% to about 60%, or about 30% to about 50% of silicate mineral. In another example, the filter aid may comprise 10% to about 50% by weight, such as about 10% to about 40%, about 20% to about 50%, or about 20% to about 40% of adsorbent.

[0058] In some exemplary methods herein, silicate mineral particles can be mixed with water to form a suspension or slurry. Sodium silicate solution, potassium silicate solution, and / or magnesium sulfate solution (if the coating includes magnesium silicate) can be added to the suspension, and the mixture can be stirred or agitated to precipitate the silicates. The sodium silicate can include, for example, sodium orthosilicate (Na4SiO4), sodium metasilicate (Na2SiO3), and / or sodium disilicate (Na2SiO5). The magnesium sulfate can be any magnesium sulfate that reacts with the sodium silicate to precipitate the magnesium silicate. For example, the magnesium sulfate can be aqueous magnesium sulfate, which can be diluted and then combined with the sodium silicate solution to achieve the desired molarity for precipitation.

[0059] According to some embodiments of the present disclosure, a filter aid can be formed by treating a composite material with an acid and then combining the material with an alkali silicate. Without wishing to be bound by any particular theory, it is believed that the acid treatment reacts with the surface of the silicate coating, thereby improving the adsorption and / or impurity removal properties of the composite material. According to some examples, the acid treatment can alter the surface chemistry of the composite material. For example, the acid treatment can lower the surface pH of the silicate coating, which can promote adsorption of impurities such as metals, soaps, and FFAs from non-aqueous liquids such as oils and oil mixtures.

[0060] For example, the composite material can be treated with at least one weak acid, such as citric acid, acetic acid, oxalic acid, malic acid, tartaric acid, ascorbic acid, or a mixture thereof. The acid treatment can be carried out by mixing the coated silicate mineral particles with the acid or a mixture of acid and water. According to some embodiments, the acid treatment can include spraying the acid or a mixture of acid and water onto the material. In some examples herein, the acid-treated composite material can then be optionally dried at an elevated temperature, for example, a temperature above about 70°C or a temperature in the range of about 70°C to about 120°C, before combining the composite material with an alkali silicate, such as sodium metasilicate.

[0061] In some instances, the composite material is not treated with an acid before combining the material with the alkali silicate to form the filter aid.

[0062] According to some embodiments of the present disclosure, the filter aid may contain about 0.5% to about 20% by weight of water, such as about 5% to about 20% by weight, about 5% to about 15% by weight, about 10% to about 20% by weight, about 0.5% to about 10% by weight, about 2% to about 8% by weight, about 5% to about 10% by weight, about 1% to about 5% by weight, about 6% to about 9% by weight, about 2.5% to about 4.5% by weight, or about 3% to about 5% by weight of water. For example, a method for making the filter aid may include at least partially coating a silicate mineral with inorganic silica or silicate, combining the composite material with an alkali silicate, and adding about 1% to about 10% by weight of water to prepare the material. Without intending to be bound by theory, it is believed that the addition of moisture can improve the filtration performance of the filter aid through, for example, the formation of FFA salts with alkali silicates and subsequent adsorption of the FFA salts onto the composite material.

[0063] The filter aid herein can be used to filter various non-aqueous liquids. For example, the liquid can be an oil or oil mixture, including, for example, edible oils, such as oils derived from animal or plant materials useful in cooking. Suitable oils can include palm oil, palm kernel oil, butter, ghee, cocoa butter, cocoa butter substitutes, illipe butter, shea butter, canola oil, castor oil, coconut oil, coriander oil, corn oil, cottonseed oil, hazelnut oil, hempseed oil, linseed oil, mango kernel oil, olive oil, peanut oil, rapeseed oil, rice bran oil, safflower oil, soybean oil, sunflower oil, animal fats and oils (e.g., duck fat, lard, tallow, fish oil), and mixtures thereof. Before filtering, the oil can be subjected to one or more refining steps, including, for example, degumming, bleaching, deodorizing, and / or interesterification, such as by chemical or enzymatic treatment. In at least one example, the oil is refined. Prior to filtration, the oil may be subjected to other processing steps such as fractionation.

[0064] In some examples, the oil comprises one or more palm-derived oils. Palm-derived oils include palm oil, palm oil stearin, palm oil olein, palm kernel oil, palm kernel stearin, and palm kernel olein, as well as transesterification products thereof. In some examples, the vegetable oil comprises palm oil or a fraction thereof. Palm oil fractions include palm oil olein, palm oil stearin, palm mid-fractions, and transesterification products thereof. The vegetable oil may comprise refined palm oil or a fraction thereof, such as palm oil olein or palm oil stearin.

[0065] According to some embodiments of the present disclosure, the oil comprises cooking oil, such as frying oil, which may include one or more of the exemplary fats and oils listed above. The oil can be filtered according to the present disclosure before and / or after use in cooking (e.g., the oil to be filtered comprises used cooking oil). For example, the filter aid herein can be used to filter used cooking oil, for example, to improve the quality of the oil used in the subsequent cooking (e.g., frying) process. The oil to be filtered may contain FFAs and / or other components that are generally considered to be contaminants that should be removed.

[0066] According to some embodiments of the present disclosure, this method can include passing liquid through the filter aid disclosed herein or otherwise contacting liquid with the filter aid disclosed herein.In some examples, the filter aid can be directly added to the liquid to be filtered, which is generally known as body feed method.In an exemplary filtration process, oil containing FFA can be mixed with the composite filter disclosed herein to form a mixture. The oil can contain at least 0.05 wt.% FFAs, e.g., from about 0.05 wt.% to about 10.0 wt.%, from about 0.1 wt.% to about 8.0 wt.%, from about 0.5 wt.% to about 5.0 wt.%, from about 1.0 wt.% to about 5.0 wt.%, from about 5.0 wt.% to about 10.0 wt.%, from about 7.0 wt.% to about 9.0 wt.%, from about 4.0 wt.% to about 6.0 wt.%, from about 1.0 wt.% to about 3.0 wt.%, from about 1.5 wt.% to about 2.5 wt.%, from about 0.05 wt.% to about 2.0 wt.%, or from about 0.1 wt.% to about 3.0 wt.% FFAs. For example, the oil can contain about 0.5%, about 0.7%, about 1.0%, about 1.2%, about 1.4%, about 1.6%, about 1.8%, about 2.0%, about 2.2%, about 2.4%, or about 2.5% by weight of FFAs.

[0067] The mixture of oil and filter aid may contain about 0.05 wt. % to about 10.0 wt. % of the filter aid, based on the weight of the oil. In some instances, the filter aid may be mixed with the oil in a dry form, for example, as a granular filter aid. In other instances, the filter aid may be prepared as an aqueous suspension, for example, in an amount ranging from about 1.0 wt. % to about 10.0 wt. % of the filter aid, based on the total weight of the aqueous suspension.

[0068] The oil can be agitated, for example, to properly distribute the filter aid in the oil. In some examples, the oil (or oil / aqueous mixture) can be heated to or at a temperature ranging from about 50°C to about 130°C or from about 60°C to about 120°C, for example, about 70°C, about 80°C, about 90°C, about 100°C, or about 110°C. In some embodiments, the oil can be at a temperature as high as 120°C to 160°C. After a period sufficient for filtering the liquid, the particles can be recovered and removed from the liquid. For example, FFAs can be removed from the oil by removing the material from the oil upon formation of FFA salts and adsorption of the FFA salts onto the composite material. The material can be removed by any suitable technique, for example, filtration, centrifugation, etc.

[0069] In some cases, the filtration method may include pre-coating at least one filter medium with a filter aid and contacting the at least one filter medium with the liquid to be filtered. The one or more filter mediums may comprise a septum (e.g., a mesh screen, membrane, or pad) and a cylindrical tube or wafer-like structure covered with plastic or sufficiently finely textured metal fibers. In certain cases, the one or more filter mediums may comprise a porous structure with voids that allow materials of a certain size to pass through the filtration device. The filter aid may be first applied to the septum of the filter medium in a process known as pre-coating. Pre-coating generally involves mixing a slurry of water and filter aid and introducing the slurry into the stream flowing through the septum. During this process, a thin layer of filter aid, e.g., about 1.5 mm to about 3.0 mm, may be deposited on the septum to form the filtration device.

[0070] The filter aids herein may be capable of removing at least some or substantially all of the FFAs from the oil. For example, the filter aids herein may be used to remove at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99% of the FFAs from the oil. In some examples, the filter aids remove from the oil about 40% to about 99%, e.g., about 50% to about 95%, about 60% to about 90%, about 75% to about 99%, about 80% to about 95%, or about 90% to about 99% of the FFAs. Additionally or alternatively, the methods herein may remove at least 50%, e.g., at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99% of the soaps (e.g., FFA salts formed from the FFAs) from the oil. In some examples, the filter aid can remove from about 75% to about 99%, from about 80% to about 99%, from about 90% to about 99%, or from about 95% to about 99% of the soap (derived from FFAs) from the oil. In some examples, the filter aid can remove substantially all of the soap from the oil (greater than 99% soap removal).

[0071] In one aspect, the optional addition of an alkali carbonate or alkali bicarbonate to the oil before or during filtration can result in enhanced free fatty acid removal. In one aspect, the addition of the alkali carbonate or alkali bicarbonate can result in filtration at elevated temperatures, for example, above about 120°C, above about 130°C, or above about 140°C. In one aspect, the elevated temperatures can be due to residual heat from the use temperature of the frying oil, thereby reducing the need for cooling before the free fatty acid removal process. In this way, formulations that perform well at elevated temperatures can provide better user utility.

[0072] Aspects of the present disclosure are further described by reference to the following non-limiting numbered exemplary embodiments.

[0073] 1. A filter aid comprising: (a) an alkali silicate; and (b) a composite material comprising a silicate mineral at least partially coated with inorganic silica or silicate.

[0074] 2. A filter aid comprising (a) an alkali silicate and (b) a silicate mineral, wherein at least a portion of the alkali silicate is present as a coating on the silicate mineral, and wherein the ratio of the alkali silicate to the silicate mineral in the filter aid is in the range of about 1:4 to 4:1 by weight.

[0075] 3. A filter aid containing an alkali silicate, a silicate mineral, and an adsorbent.

[0076] 4. The filter aid according to paragraph 1, wherein the alkali silicate comprises about 10% to about 70% by weight of the filter aid.

[0077] 5. The filter aid of paragraph 3, comprising about 10% to about 60% by weight of the alkali silicate, about 10% to about 60% by weight of the silicate mineral, and about 10% to about 60% by weight of the adsorbent.

[0078] 6. The filter aid of paragraph 3, wherein the adsorbent is at least partially coated on a silicate mineral.

[0079] 7. The filter aid of paragraph 3, wherein the adsorbent is a particulate material that is substantially unbound with silicate minerals.

[0080] 8. The filter aid of any preceding paragraph, wherein the alkali silicate comprises sodium silicate, potassium silicate, or a mixture thereof.

[0081] 9. The filter aid of any preceding paragraph, wherein the alkali silicate comprises sodium metasilicate.

[0082] 10. The filter aid of any preceding paragraph, wherein the sodium metasilicate is sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, sodium metasilicate anhydrous, or a mixture thereof.

[0083] 11. The filter aid of any preceding paragraph, wherein the alkali silicate comprises sodium metasilicate pentahydrate.

[0084] 12. The filter aid of any preceding paragraph, wherein the silicate mineral comprises biogenic silica.

[0085] 13. The filter aid of any preceding paragraph, wherein the silicate mineral comprises diatomaceous earth.

[0086] 14. The filter aid of any preceding paragraph, wherein the silicate mineral comprises perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or a combination thereof.

[0087] 15. The filter aid of any of paragraphs 3 to 7, wherein the adsorbent is magnesium silicate.

[0088] 16. The filter aid of paragraph 1, wherein the inorganic silica or silicate comprises silica gel, sodium silicate, magnesium silicate, or a combination thereof.

[0089] 17. The filter aid of paragraph 1, wherein the inorganic silica or silicate is precipitated on the surface of the silicate mineral.

[0090] 18. The filter aid of paragraph 1, wherein the composite material comprises about 50% to about 95% by weight of biogenic silica.

[0091] 19. The filter aid of paragraph 1, wherein the composite material comprises about 5% to about 80% by weight of inorganic silica or silicate, based on the total weight of the composite material.

[0092] 20. The filter aid of any preceding paragraph having a permeability in the range of about 0.05 darcy to about 3.0 darcy.

[0093] 21.About 5m 2 / g ~ approx. 450m 2 The filter aid of any preceding paragraph having a BET surface area in the range of 1 / g.

[0094] 22. The filter aid of paragraph 1, wherein the particle size distribution of the composite material has a d50 diameter in the range of about 5 μm to about 300 μm.

[0095] 23. The filter aid of paragraph 1, wherein the composite material has a median pore size (4V / A) in the range of about 0.1 μm to about 10.0 μm.

[0096] 24. Composite materials have a strength of approximately 5 lb / ft 3 ~30lb / ft 3 2. The filter aid of paragraph 1, having a wet density in the range of

[0097] 25. A filter aid according to any preceding paragraph, comprising about 0.5% to about 20% by weight of water, for example about 1% to about 10% by weight of water, based on the total weight of the filter aid.

[0098] 26. A composition comprising the filter aid of any of the preceding paragraphs.

[0099] 27. The composition of paragraph 26, comprising at least 80% by weight of the filter aid and about 1.0% by weight to about 10.0% by weight of water, based on the total weight of the composition.

[0100] 28. The composition of paragraph 26 or 27, having a pH in the range of about 9.0 to about 13.0.

[0101] 29. Use of a filter aid according to any of paragraphs 1 to 25 or a composition according to any of paragraphs 26 to 28 for filtering oil.

[0102] 30. A method of filtering oil, comprising combining the oil with the filter aid of any of paragraphs 1-25 to form a mixture.

[0103] 31. The method of paragraph 30, further comprising heating the mixture.

[0104] 32. The method of paragraph 30 or 31, wherein the oil contains about 0.05% to about 10.0% by weight of free fatty acids.

[0105] 33. The method of paragraph 30 or 31, further comprising separating at least a portion of the filter aid from the oil, wherein the filter aid removes at least 50% by weight, at least 65% by weight, or at least 70% by weight of the free fatty acids from the oil.

[0106] 34. The method of any of paragraphs 30 to 33, wherein the oil comprises an edible oil.

[0107] 35. The method of any of paragraphs 30-34, wherein the mixture comprises about 0.05% to about 10.0% filter aid by weight of the oil.

[0108] 36. A method for making a filter aid according to any of paragraphs 1, 4, 8-14, and 16-25.

[0109] 37. The method of paragraph 36, comprising preparing a composite material by at least partially coating a silicate mineral with inorganic silica or silicate, and combining the composite material with an alkali silicate.

[0110] 38. The method of paragraph 36 or 37, wherein the silicate mineral comprises diatomaceous earth, and preparing the composite material comprises precipitating inorganic silica or silicate onto the surface of the diatomaceous earth.

[0111] 39. The method of any of paragraphs 36-38, further comprising adding water to the filter aid such that the filter aid contains about 0.5% to about 10% by weight of water based on the total weight of the filter aid.

[0112] The following examples are intended to illustrate, but not limit, the present disclosure, and it is understood that the present disclosure includes additional embodiments commensurate with the above description and examples below. [Example]

[0113] Example 1 Experiments were conducted to compare the performance of various filter aid compositions in filtering oil samples with high FFA content. The oil sample used in each case was a commercially available vegetable oil for home cooking (containing less than 0.1% FFA by weight) to which 2% oleic acid by weight had been added to mimic FFA contamination.

[0114] Four compositions were tested, as outlined in Table 1 below. Samples 1 and 2 were prepared in accordance with the present disclosure as filter aids containing sodium metasilicate pentahydrate and magnesium silicate-coated or silica gel-coated diatomaceous earth particles, with greater than 95% of the particles being less than 400 μm in size and greater than 95% of the particles being greater than 5 μm in size. Sample 1 was prepared with 30 wt% Na2SiO3·5H2O and 70 wt% DE / MgO-SiO2 composite (containing 60 wt% MgO-SiO2 (having a molar ratio SiO2 / MgO ranging from about 2.5 to about 3.2) coated on 40 wt% DE particles) (Imerys). Sample 2 was prepared with 30 wt% Na2SiO3·5H2O and 70 wt% DE / SiO2 composite (containing 60 wt% silica gel coated on 40 wt% DE particles) (Imerys). Two reference samples (Samples 3 and 4) were prepared from MAGNESOL™ 600R and MAGNESOL™ PolySorb 30 / 40, both commercially available products from Dallas Group. Sample 3 was DALSORB™ (containing 60 wt% Na2SiO3 and 40 wt% MgSiO3), and Sample 4 was a 50 / 50 mixture of MAGNESOL™ 600R and MAGNESOL™ PolySorb 30 / 40 (containing 30 wt% Na2SiO3 and 70 wt% MgSiO3).

[0115] In each case, 150 grams of oil was heated to 100°C and 3 grams of the dry composition sample (2% by weight of oil) was added. The mixture was stirred at 100°C for 60 minutes. The treated oil was then vacuum filtered through a heated Buchner funnel (100±5°C) equipped with Whatman #4 filter paper. The time required to filter the 150 gram oil sample was recorded to an accuracy of ±1 minute.

[0116] The filtered oil samples were titrated for FFA content with NaOH in isopropanol using phenolphthalein as the indicator (AOCS Official Method Aa 6-38). The percent removal of FFA was calculated according to Equation 3:

number

[0117] To determine soap removal, filtered oil samples were titrated for soap content with HCl in acetone with 2% water using bromophenol blue as the indicator (AOCS Recommended Practice Cc 17-95). Percent soap removal was calculated according to Equation 4:

number

[0118] The amount of theoretical soap produced was calculated according to Equation 5:

number

[0119] The results are shown in Table 1 below.

[0120] [Table 1]

[0121] Samples 1 and 2 were found to provide higher FFA removal, equal or higher soap (from FFA) removal, and faster filtration times compared to the commercial products.

[0122] Example 2 Using the same procedure described in Example 1, additional filter aid compositions (Samples 5, 6, and 9-14) and reference compositions (7 and 8) were prepared and tested for filtration time, % FFA removal, and % soap removal, as outlined in Table 2. For these studies, two different types of composite magnesium silicate-coated DE particles were used: 60 wt.% MgO-SiO2 (having a molar ratio of SiO2 / MgO ranging from about 2.5 to about 3.2) coated on 40 wt.% DE particles (Samples 5, 6, 9, and 11) (Imerys), or 40 wt.% MgO-SiO2 (having a molar ratio of SiO2 / MgO ranging from about 2.5 to about 3.2) coated on 60 wt.% DE particles (Samples 10 and 13) (Imerys). Silica gel-coated DE particles were used in Samples 12 and 14 (Imerys). Anhydrous sodium silicate (molar ratio SiO / NaO=2.0) and BRITESIL™ C20 sodium silicate (molar ratio SiO / NaO=2.0; 17.5% moisture) were obtained from PQ Corporation. Water was added to Sample 6 to provide approximately 8% moisture by weight.

[0123] [Table 2]

[0124] Comparing these studies with Example 1 suggests that various alkali silicates other than sodium metasilicate were successful in removing FFAs from oil. It was found that compositions containing sodium silicate with a higher SiO / NaO molar ratio generally resulted in lower FFA removal. Additionally, compositions with silicate-coated diatomaceous earth particles resulted in higher FFA removal compared to silica gel-coated particles. Furthermore, the results of Composition F suggest that adding some additional water to the filter aid can result in better FFA filtration performance.

[0125] Example 3 A sample of the silicate mineral coated with alkali silicate was assayed using the same general procedure as described in Example 1, except that the free fatty acid content of the oil used was approximately 0.82%. A sample of filter aid containing diatomite coated with sodium silicate was prepared as follows: 1600 g of sodium silicate (Oxy Chemicals, Grade 50), 560 g of diatomite, and 384 g of deionized water were mixed. The resulting mixture was spray-dried in a lab-scale spray dryer with an inlet temperature set at 320°C, an outlet temperature set at 108°C, and a pump feed rate set at 21 rpm.

[0126] The resulting spray-dried material is considered to be sodium silicate-coated DE (NaSil-DE) (approximately 10% total moisture, as determined by loss on drying at 400°C) with a NaSil:DE ratio of 1.5:1 (w / w) and approximately 15% moisture in the sodium silicate coating. BRITESIL™ C20 silica gel was used as a control in Samples 18-20. In Sample 20, 50% BRITESIL™ C20 was mixed with 60 Å pore size, 230 mesh to 400 mesh particle size, and 550 m 2 The silica gel was mixed with 50% high purity silica gel (commercially available from Sigma-Aldrich) with a BET surface area of ​​1000 s / g.

[0127] [Table 3]

[0128] As shown in Table 3 above, the composite material "NaSil-DE" achieved very good filtration time and FFA removal, as well as sufficient soap removal performance when used alone (Sample 15). The combination of 80% NaSil-DE and 20% DE / SiO2 composite (Sample 17) provided excellent soap removal and is generally considered to provide the best balance among the three performance factors. The combination of 80% NaSil-DE and 20% sodium metasilicate pentahydrate (Na2SiO3·5H2O) (Sample 16) provided nearly complete FFA removal.

[0129] Example 4 Samples were assayed as set forth in Table 4 below to evaluate the effect of using adsorptive magnesium silicate, using the same general procedure as described in Example 1, except that the free fatty acid content of the oil used was about 0.82%. The magnesium silicate (MgSil) used was precipitated magnesium silicate (particle size Dv=60 μm, Dn=9.3 μm, approximately 500 μm) commercially available from Shangyu Jiehua Co., Ltd. 2 / g BET surface area).

[0130] [Table 4]

[0131] The combination of sodium metasilicate and milli-ground expanded perlite (Sample 23) achieved very good FFA and soap removal performance. However, composites with magnesium silicate and mineral filter aids (Samples 21 and 22) achieved even better FFA and soap removal performance. A mixture of 40% sodium metasilicate and 60% MgSil was tested and found to cause filter clogging, likely due to an inability to effectively filter soap. Samples 21-23 completed filtration within 3 minutes, which corresponds to a filtration rate that is good for practical use.

[0132] Example 5: It has been found that the inclusion of sodium carbonate (e) or sodium bicarbonate (e) in the filter aid formulation has little effect on FFA reduction at low temperatures. In particular, treating vegetable oil (150 g) containing 2% oleic acid with a 2% formulation (3 g) containing a complex of 40% NaHCO3 + 60% (DE-SiO2) or 40% Na2CO3 + 60% (DE-SiO2) for 60 minutes resulted in a relative removal of approximately 10% FFA (i.e., an absolute reduction of 0.2% FFA). However, when the temperature was increased to 146°C (290°F), the FFA reduction increased to 71% (i.e., an absolute reduction of 0.85% FFA).

[0133] Other aspects and embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein.

[0134] It is intended that the specification and examples herein be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

Claims

1. 1. A method for making a filter aid comprising: (a) an alkali silicate comprising sodium metasilicate; and (b) a composite material comprising diatomaceous earth as a silicate mineral at least partially coated with inorganic silica or silicate, the method comprising: preparing the composite material by at least partially coating the diatomaceous earth with the inorganic silica or silicate; and combining the composite material with the alkali silicate.

2. The method described in claim 1, wherein preparing the composite material includes precipitating the inorganic silica or silicate on the surface of the diatomaceous earth.

3. 10. The method of claim 1, further comprising adding water to the filter aid so that the filter aid contains 0.5% to 10% by weight of water based on the total weight of the filter aid.

4. 2. The method of claim 1, wherein the ratio of the alkali silicate to the silicate mineral in the filter aid ranges from 1:4 to 4:1 by weight.

5. The method of claim 4 , wherein the alkali silicate further comprises sodium silicate, potassium silicate, or a mixture thereof.

6. 5. The method of claim 4, wherein the sodium metasilicate is sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, sodium metasilicate anhydrous, or a mixture thereof.

7. The method of claim 4 , wherein the alkali silicate comprises sodium metasilicate pentahydrate.

8. 5. The method of claim 4, wherein the silicate mineral comprises perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or a combination thereof.

9. 5. The method of claim 4, wherein the filter aid has a permeability in the range of 0.05 darcy to 10.0 darcy.

10. The filter aid is 0.2 m ２ / g~450m ２ 5. The method of claim 4, wherein the sintered body has a BET surface area in the range of 1 / g.

11. 10. Use of the filter aid made by the method of claim 4 for filtering oil.

12. A filter aid comprising an alkali silicate comprising sodium metasilicate, a silicate mineral comprising diatomaceous earth, and an adsorbent which is a particulate material substantially unbound with the silicate mineral.

13. 13. The filter aid of claim 12, comprising 10% to 60% by weight of alkali silicate, 10% to 60% by weight of silicate mineral, and 10% to 60% by weight of adsorbent.

14. 13. The filter aid of claim 12, wherein the adsorbent is at least partially coated on the silicate mineral.

15. 13. The filter aid of claim 12, wherein the alkali silicate further comprises sodium silicate, potassium silicate, or a mixture thereof.

16. 13. The filter aid of claim 12, wherein the sodium metasilicate is sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, anhydrous sodium metasilicate, or a mixture thereof.

17. 13. The filter aid of claim 12, wherein the alkali silicate comprises sodium metasilicate pentahydrate.

18. 13. The filter aid of claim 12, wherein the silicate mineral comprises perlite, pumice, pumice powder, obsidian, tartar, volcanic ash, or a combination thereof.

19. 13. The filter aid of claim 12, wherein the adsorbent is magnesium silicate.

20. 13. The filter aid of claim 12, having a permeability in the range of 0.05 darcy to 3.0 darcy.

21. 5m ２ / g~450m ２ 13. The filter aid of claim 12, having a BET surface area in the range of 1 / g.

22. 13. The filter aid of claim 12, comprising 0.5% to 20% by weight of water, for example 1% to 10% by weight of water, based on the total weight of the filter aid.

23. 13. Use of the filter aid according to claim 12 for filtering oil.

24. 13. A method of filtering oil, comprising combining the oil with the filter aid of claim 12 to form a mixture.

25. 25. The method of claim 24, further comprising heating the mixture.

26. 25. The method of claim 24, wherein the oil comprises 0.05% to 10.0% by weight of free fatty acids.

27. 25. The method of claim 24, further comprising separating at least a portion of the filter aid from the oil, wherein the filter aid removes at least 50%, at least 65%, or at least 70% by weight of the free fatty acids from the oil.

28. 25. The method of claim 24, wherein the oil comprises an edible oil.

29. 25. The method of claim 24, wherein the mixture comprises 0.05% to 10.0% of the filter aid by weight of the oil.

30. 5. The method of claim 4, further comprising combining the composite material and the alkali silicate with a sorbent, the sorbent being a particulate material substantially unbound with the silicate mineral.

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