Products for PFAS adsorption

Abstract

Disclosed is a product for adsorbing one or more PFAS from a liquid. The product can include (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, and (b) attapulgite or sepiolite surface-functionalized with a mercapto surface coating solution containing a surface coating agent containing one or more mercapto groups chemically bonded to the attapulgite or sepiolite surface. When the quaternary amine surface coating solution contains a mono-quaternary amine compound, the product does not contain a di-quaternary amine. When the quaternary amine surface coating solution contains a di-quaternary amine compound, the product does not contain a mono-quaternary amine. Also disclosed are a method for manufacturing the product and a method for adsorbing PFAS in a liquid using the product.

Description

Cross - References to Related Applications

[0001] This application claims the priority and benefit of U.S. Patent Application No. 17 / 865,721, filed on July 15, 2022, and also claims the priority and benefit of U.S. Patent Application No. 18 / 203,892, filed on May 31, 2023, which is a continuation - in - part of U.S. Patent Application No. 17 / 865,721, filed on July 15, 2022.

Technical Field

[0002] The present disclosure generally relates to products containing attapulgite or sepiolite, or products containing attapulgite and sepiolite suitable for adsorbing PFAS from liquids.

[0003] Background Per- and polyfluoroalkyl substances (conventionally referred to as PFAS, and collectively as PFAS) are a group of artificial chemicals that include, but are not limited to, perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTriA), perfluorotetradecanoic acid (PFTeA), perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluorobutanesulfonic acid (PFBS), perfluoropentanesulfonic acid (PFPeS), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanesulfonic acid (PFHpS), perfluorooctanesulfonic acid (PFOS), perfluorononanesulfonic acid, perfluorodecanesulfonic acid (PFDS), perfluorododecanesulfonic acid (PFDoS), perfluorooctanesulfonamide (FOSA), N-ethylperfluoro-1-octanesulfonamide, NMeFOSA, N-methylperfluorooctanesulfonamide acetic acid (NMeFOSAA), N-ethylperfluorooctanesulfonamide acetic acid (NEtFOSAA), 2-(N-methylperfluoro-1-octanesulfonamide) ethanol, 2-(N-ethylperfluoro-1-octanesulfonamide) ethanol, 4:2 FTS, 6:2 FTS, 8:2 FTS, 10:2 FTS, HFPO-DA, 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, 11-chloroeicosadecafluoro-3-oxaundecane-1-sulfonic acid, or similar chemicals. PFAS have been widely used in industry and consumer products to date. PFAS are considered emerging contaminants. PFAS contaminants in industrial and municipal wastewater can enter groundwater, water bodies and other water environments, posing potential health risks to humans and wildlife.PFAS are relatively stable chemicals and are known to persist over long periods. PFAS have been found in the blood of people and animals around the world. PFAS are present at low concentrations in a variety of foods and in the environment. Research has shown that some exposure to PFAS in the environment can be associated with harmful effects on human and animal health. The remediation of PFAS-contaminated water tends to be very difficult.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Commercially available removal technologies commonly include activated carbon adsorption, anion exchange resins, and high-pressure membranes. Activated carbon is a low-efficiency technology. Anion exchange resin and high-pressure membrane technologies are expensive due to high material and equipment costs.

[0005] U.S. Patent No. 9,284,201 (hereinafter, the '201 patent), issued on March 15, 2016, describes a process for a modified clay adsorbent using oleylamine and octylamine or a mixture thereof. There is a need for an effective and inexpensive removal medium capable of separating PFAS from liquids.

[0006] Summary of the Disclosure In one aspect of the present disclosure, a product for adsorbing at least one PFAS in a liquid is disclosed. The product comprises attapulgite surface-functionalized with: (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, wherein the mono-quaternary amine compound contains one or more mono-quaternary amines attached to the attapulgite surface and the di-quaternary amine compound contains one or more di-quaternary amines attached to the attapulgite surface; and (b) a surface coating agent containing one or more mercapto groups chemically bonded to the attapulgite surface. When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain di-quaternary amines. When the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain mono-quaternary amines. The product, or the surface-functionalized attapulgite, has a surface area in the range of 45 - 160 square meters per gram (m 2 / g) or 50 - 100 m 2 / g as measured by the BET method, and the product, or the surface-functionalized attapulgite, has a particle size distribution with a d50 of 6 - 30 micrometers (μm), or 10 - 25 micrometers, or 12 - 25 micrometers, or 12 - 23 micrometers.

[0007] In one embodiment, the surface coating agent may be mercaptosilane.

[0008] In any one or group of the above embodiments, the product is in powder form and / or does not have to be extruded.

[0009] In any one of the above embodiments, the product may have a PFAS removal efficiency of 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% for at least one PFAS in the liquid at a product loading of 0.5 - 2 grams (g) of product per liter of liquid over 12 - 25 hours.

[0010] In any one of the above embodiments, the product, or the surface-functionalized attapulgite, may have a porosity of 40-90% and a pore volume of 0.7-1.5 mL / g.

[0011] In any one of the above embodiments, the weight percentages of the components of the product are as follows: 85-94 wt% attapulgite; 2.5-15 wt% of the following: (i) mono-quaternary amine or (ii) di-quaternary amine; and 1-8 wt% surface coating agent.

[0012] In any one of the above embodiments, the product may not contain oleylamine and octylamine.

[0013] In any one of the above embodiments, the product may not contain residual acid.

[0014] In another aspect of the present disclosure, a method for manufacturing a product for adsorbing at least one PFAS from a liquid is disclosed. The method includes selecting attapulgite as a feedstock, wherein the attapulgite selected as the feedstock prior to surface treatment contains 7-16 wt% or 9-14 wt% moisture as measured at a temperature of 104 °C. The method further includes surface treating the attapulgite with a quaternary amine surface coating solution, the quaternary amine surface coating solution containing (i) a mono-quaternary amine compound, the mono-quaternary amine compound containing one or more mono-quaternary amines attached to the surface of the attapulgite, or (ii) a di-quaternary amine compound, the di-quaternary amine compound containing one or more di-quaternary amines attached to the surface of the attapulgite; and surface treating the attapulgite with a mercapto surface coating solution, the mercapto surface coating solution containing a surface coating agent containing one or more mercapto groups chemically bonded to the surface of the attapulgite, wherein the resulting product has a BET-measured surface area of 45-160 m 2Having a surface area in the range of / g, where when the quaternary amine surface coating solution contains a mono - quaternary amine compound, the product does not contain a di - quaternary amine, and where when the quaternary amine surface coating solution contains a di - quaternary amine compound, the product does not contain a mono - quaternary amine.

[0015] In one embodiment, the weight percentages of the components of the product may include the following: 85 - 94 wt% attapulgite; 2.5 - 15 wt% of (i) one or more mono - quaternary amines or (ii) one or more di - quaternary amines; and 1 - 8 wt% of a surface coating agent containing one or more mercapto groups, where the product does not contain oleylamine and octylamine.

[0016] In any one of the embodiments of the above - mentioned method, the quaternary amine surface coating solution may further contain water, where the mercapto surface coating solution further contains a solvent, and where the surface coating agent contains mercaptosilane.

[0017] In any one of the embodiments of the above - mentioned method, the surface treatment of attapulgite with the mercapto surface coating solution may follow the surface treatment of attapulgite with the quaternary amine surface coating solution.

[0018] In any one of the embodiments of the above - mentioned method, the quaternary amine surface coating solution may further contain water.

[0019] In any one of the embodiments of the above - mentioned method, the method may further include drying the attapulgite, where: (a) one or more mono - quaternary amines are dried on the attapulgite of the produced product, or one or more di - quaternary amines are dried on the attapulgite of the produced product, (b) the mercapto surface coating solution is dried on the attapulgite of the produced product, and (c) the produced product is in powder form or has not been extruded.

[0020] In any one embodiment of the above method, the product may have a particle size distribution with a d of 6 - 30 microns or 10 - 25 microns or 12 - 25 microns or 12 - 23 microns. 50 It may have a particle size distribution with a d of 6 - 30 microns or 10 - 25 microns or 12 - 25 microns or 12 - 23 microns.

[0021] In any one embodiment of the above method, the product may have a PFAS removal efficiency of 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% for at least one PFAS in the liquid at a product loading of 0.5 - 2 g of product per liter of liquid over 12 - 25 hours.

[0022] In yet another aspect of the present disclosure, a method for adsorbing at least one PFAS in a liquid is disclosed. The method comprises: (a) a quaternary amine surface coating solution comprising a mono - quaternary amine compound or a di - quaternary amine compound, wherein the mono - quaternary amine compound comprises one or more mono - quaternary amines attached to the attapulgite surface and the di - quaternary amine compound comprises one or more di - quaternary amines attached to the attapulgite surface; and (b) contacting a product comprising attapulgite surface - functionalized with a surface coating agent comprising one or more mercapto groups that chemically bond to the attapulgite surface with the liquid; and separating the product from the liquid to recover a liquid resulting in an amount of PFAS less than that of the liquid prior to mixing, wherein the weight percentages of the components of the product are as follows: 85 - 94 wt% attapulgite, 2.5 - 15 wt% of (i) one or more mono - quaternary amines or (ii) one or more di - quaternary amines, and 1 - 8 wt% of a surface coating agent comprising one or more mercapto groups, wherein when the quaternary amine surface coating solution comprises one or more mono - quaternary amine compounds, the product does not contain a di - quaternary amine compound, and when the quaternary amine surface coating solution comprises one or more di - quaternary amine compounds, the product does not contain a mono - quaternary amine compound, and wherein the product has a BET - measured surface area of 45 - 160 m 2It has a surface area in the range of / g, and the removal efficiency of PFAS in the product there is 10 - 100% at a product load of 0.5 - 2 g per liter of the liquid.

[0023] In any one embodiment of the above methods, the liquid may include water, edible oil, wastewater, treated water, or a combination thereof.

[0024] In any one embodiment of the above methods, the surface coating agent may include mercaptosilane.

[0025] In any one embodiment of the above methods, the contact may be 12 - 25 hours, and the PFAS removal efficiency of the product for at least one PFAS at a product load of 0.5 - 2 g per liter of the liquid is 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100 or 97 - 100%.

[0026] In another aspect of the present disclosure, a product for adsorbing at least one PFAS in a liquid is disclosed. The product may include sepiolite surface-functionalized with: (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, where the mono-quaternary amine compound contains one or more mono-quaternary amines attached to the sepiolite surface and the di-quaternary amine compound contains one or more di-quaternary amines attached to the sepiolite surface; and (b) a surface coating agent containing one or more mercapto groups chemically bonded to the sepiolite surface. When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain di-quaternary amines, and when the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain mono-quaternary amines. Wherein the product or the surface-functionalized sepiolite has a BET-measured surface area of 76 - 276 m 2 / g or 80 - 254 m 2may have a surface area in the range of / g, where the product or surface-functionalized sepiolite has a d of 10-25 microns or 11-22 microns or 12-21 microns 50 and may have a particle size distribution having. In one embodiment, the surface coating agent may be mercaptosilane. In any one or more embodiments, the product may be in powder form and / or may not be extruded. In any one or more embodiments, the product may have a PFAS removal efficiency of 70-100%, 80-100%, 90-100%, 95-100% or 97-100% for at least one PFAS in a liquid at a product loading of 0.5-2 g of product per liter of liquid over 12-25 hours. In any one or more embodiments, the product may have a porosity of 62-86% and a pore volume of 1.3-3 mL / g. In any one or more embodiments, the weight percentages of the components of the product may include 76-97 wt% sepiolite; 1-16 wt% of the following: (i) mono-quaternary amine or (ii) di-quaternary amine; and 0.5-8 wt% surface coating agent. In any one or more embodiments, the product does not contain oleylamine and octylamine. In any one or more embodiments, the product may not contain residual acid.

[0027] In another aspect of the present disclosure, a method for manufacturing a product for adsorbing at least one PFAS from a liquid is disclosed. The method comprises selecting sepiolite as a feedstock, wherein the sepiolite selected as the feedstock prior to surface treatment contains 16-20 wt% moisture as measured by loss on ignition (LOI); surface treating the sepiolite with a quaternary amine surface coating solution, wherein the quaternary amine surface coating solution is (i) a mono-quaternary amine compound, the mono-quaternary amine compound containing one or more mono-quaternary amines that adhere to the surface of the sepiolite, or (ii) a di-quaternary amine compound, the di-quaternary amine compound containing one or more di-quaternary amines that adhere to the surface of the sepiolite; and surface treating the sepiolite with a mercapto surface coating solution, the mercapto surface coating solution optionally containing a surface coating agent containing one or more mercapto groups that chemically bond to the surface of the sepiolite, wherein the resulting product has a BET surface area of 76-276 m 2It may have a surface area in the range of / g, and when the quaternary amine surface coating solution contains a mono - quaternary amine compound there, the product does not contain a di - quaternary amine, and when the quaternary amine surface coating solution contains a di - quaternary amine compound there, the product does not contain a mono - quaternary amine. In one embodiment, the weight percentages of the components of the product are as follows: 76 - 97 wt% sepiolite; 1 - 16 wt% of (i) one or more mono - quaternary amines or (ii) one or more di - quaternary amines; and 0.5 - 8 wt% of a surface coating agent containing one or more mercapto groups, where the product does not contain oleylamine and octylamine. In any one or more of the embodiments, (a) the quaternary amine surface coating solution may further contain water, (b) the mercapto surface coating solution may further contain a solvent, and (c) the surface coating agent may contain mercaptosilane. In any one or more of the embodiments, the surface treatment of sepiolite with the mercapto surface coating solution may follow the surface treatment of sepiolite with the quaternary amine surface coating solution. In the improvement, the quaternary amine surface coating solution may further contain water. In any one or more of the embodiments and / or improvements, the method further comprises drying the sepiolite, where one or more mono - quaternary amines are dried on the sepiolite of the produced product, or one or more di - quaternary amines are dried on the sepiolite of the produced product, where the mercapto surface coating solution is dried on the sepiolite of the produced product, where the produced product may be in powder form or may not be extruded. In any one or more of the embodiments and / or improvements, the product may have a particle size distribution with a d 50 in the range of 10 - 25 microns or 11 - 22 microns or 12 - 21 microns. In any one or more of the embodiments and / or improvements, the product may have a PFAS removal efficiency of 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% for at least one PFAS in a liquid at a product loading of 0.5 - 2 g of product per liter of liquid over 12 - 25 hours.

[0028] In yet another aspect of the present disclosure, a method for adsorbing at least one PFAS in a liquid is disclosed. The method comprises: (a) a quaternary amine surface coating solution comprising a mono-quaternary amine compound or a di-quaternary amine compound, wherein the mono-quaternary amine compound comprises one or more mono-quaternary amines attached to the sepiolite surface and the di-quaternary amine compound comprises one or more di-quaternary amines attached to the sepiolite surface; and (b) contacting a product comprising sepiolite surface-functionalized with a surface coating agent comprising one or more mercapto groups bonded to the sepiolite surface with the liquid; and separating the product from the liquid to recover a resulting liquid having a lower amount of PFAS than the liquid had prior to mixing, wherein the weight percentages of the components of the product are as follows: 76-97 wt% sepiolite, 1-16 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines, and 0.5-8 wt% of a surface coating agent comprising one or more mercapto groups, wherein when the quaternary amine surface coating solution comprises one or more mono-quaternary amine compounds, the product does not contain a di-quaternary amine compound, and when the quaternary amine surface coating solution comprises one or more di-quaternary amine compounds, the product does not contain a mono-quaternary amine compound, and wherein the product has a surface area in the range of 76-276 m 2 / g as measured using the BET method, and wherein the removal efficiency of the product for PFAS is 10-100% at a product loading of 0.5-2 g per liter of the liquid. In one embodiment, the liquid can include water, edible oil, wastewater, treated water, or combinations thereof. In any one or more embodiments, the surface coating agent can include mercaptosilane. In any one or more embodiments, the contacting can be for 12-25 hours, and the PFAS removal efficiency of the product for at least one PFAS at a product loading of 0.5-2 g per liter of the liquid can be 70-100%, 80-100%, 90-100%, 95-100 or 97-100%.

Brief Description of the Drawings

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[0030] Detailed Description This disclosure relates to products for PFAS adsorption from liquids. The products disclosed herein may include attapulgite or sepiolite, or both attapulgite and sepiolite. Attapulgite is sometimes called palygorskite. To avoid confusion, the term "attapulgite" as used herein means attapulgite and / or palygorskite. As is known in the art, attapulgite is a clay mineral of a chain crystal lattice type with a different structure from other clays such as montmorillonite or bentonite. That is, the tetrahedral sheet of attapulgite is divided into ribbons by inversion because the bands of adjacent tetrahedra within one type of tetrahedral sheet face in opposite directions rather than in one direction, creating a structure of ribbons of 2:1 layers joined at their edges, and the octahedral sheet is continuous only in two dimensions. Sepiolite is magnesium hydrosilicate. The structures of both attapulgite and sepiolite are similar in that tetrahedra facing the same direction form 2:1 ribbons, which extend in the a-axis direction, and sepiolite has an average b-axis width where three tetrahedral chains are connected, and attapulgite has an average b-axis width where two connected chains are joined.

[0031] Typically, activated carbon is used for PFAS adsorption. However, it is not a very efficient technique. Other techniques such as anion exchange resins and high-pressure membrane technologies are expensive due to high material and equipment costs.

[0032] Disclosed herein is a novel product that can be used as an adsorbent for at least one PFAS in a liquid. Such liquids can include, but are not limited to, water (e.g., fresh water, sea water, or other such types), edible oil, wastewater, treated water, or combinations thereof. For example, the liquid may include, or be, water-in-oil, or oil-in-water.

[0033] Such a novel product for reducing at least one PFAS in such a liquid is attapulgite, or sepiolite, or may include attapulgite and sepiolite, surface-functionalized with (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, wherein the mono-quaternary amine compound contains one or more mono-quaternary amines attached to the attapulgite / sepiolite surface and the di-quaternary amine compound contains one or more mono-quaternary amines attached to the attapulgite / sepiolite surface, and (b) a mercapto surface coating solution containing a surface coating agent containing one or more mercapto groups chemically bonded to the attapulgite / sepiolite surface.

[0034] In one embodiment, the weight percentages of the components of such a product can be as follows: 85 - 94 wt% attapulgite; 2.5 - 15 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 1 - 8 wt% of a surface coating agent containing one or more mercapto groups. When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product contains no di-quaternary amines. When the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product contains no mono-quaternary amines. The quaternary amine surface coating solution may further contain water. The mercapto surface coating solution may further contain a solvent.

[0035] Natural attapulgite (as a feedstock) may have a surface area in the range of 90 - 160 m 2 / g or 120 - 145 m 2 / g or 130 - 145 m 2 / g. In any one of the above embodiments, natural attapulgite (as a feedstock) may have a particle size distribution with a d 50 of 5 - 25 microns or 6 - 18 microns or 8 - 17 microns or 10 - 15 microns. In any one of the above embodiments, natural attapulgite (as a feedstock) may have a porosity of 50 - 90%, or 55 - 80% or 60 - 75%. In any one of the above embodiments, natural attapulgite (as a feedstock) may have a pore volume of 0.8 - 3 mL / g or 0.9 - 2 mL / g or 1 - 1.2 mL / g. In any one or more of the above embodiments or improvements, for natural attapulgite (as a feedstock), the peak position of the intrinsic pores can range from about 5 nm (nanometers) to about 25 nm, and / or the peak position of the inter pores can range from about 2 microns to about 16 microns. In the improvement, for natural attapulgite (as a feedstock), the peak position of the intrinsic pores can be in the range from about 10 nm to about 18 nm, and / or the peak position of the inter pores can be in the range from about 2.5 microns to about 10 microns.

[0036] (Surface functionalization) The product (including attapulgite) may have a surface area measured using the Brunauer - Emmett - Teller (BET) theory of 45 - 160 m 2 / g or 45 - 150 m 2 / g or 45 - 130 m 2 / g or 50 - 100 m 2It may have a surface area in the range of / g. In any one of the above embodiments, such (surface-functionalized) products (including attapulgite) may have a d of 6 - 30 microns or 10 - 25 microns or 12 - 25 microns or 12 - 23 microns 50 It may have a particle size distribution with 50 . In any one of the above embodiments, such (surface-functionalized) products (including attapulgite) may have a porosity of 40 - 90% or 40 - 80% or 50 - 75% or 55 - 70%. In any one of the above embodiments, such (surface-functionalized) products (including attapulgite) may have a pore volume of 0.7 - 1.5 mL / g or 0.9 - 1.2 mL / g or about 0.9 - 1.0 mL / g. In any one or more of the above embodiments or improvements, for such (surface-functionalized) products (including attapulgite), the peak position of the intrinsic pores can be in the range from about 5 nanometers (nm) to about 35 nm, and / or the peak position of the internal pores can be in the range from about 2 microns to about 20 microns. In the improvement, for such (surface-functionalized) products (including attapulgite), the peak position of the intrinsic pores can be in the range from about 10 nm to about 25 nm, and / or the peak position of the internal pores can be in the range from about 3 microns to about 11 microns. In any one or more of the above embodiments, such products may be in powder form or non-extruded form (without extrusion before and after surface functionalization). In any one or more of the above embodiments, attapulgite can be natural attapulgite that has not been heat-treated (at temperatures up to about 1000 °C from 300 °C) and / or fired (e.g., at temperatures above about 1000 °C) before surface functionalization, or it can contain them. In any one or more of the above embodiments, attapulgite may be in powder form. In any one or more of the above embodiments, attapulgite has not been extruded (not extruded either before or after surface functionalization).

[0037] In any one of the above embodiments, the (surface-functionalized) product containing attapulgite may have a PFAS removal efficiency of 70-100%, 80-100%, 90-100%, 95-100%, or 97-100% for PFAS in the liquid at a product loading of 0.5-2 grams (g) of the product per liter of the liquid, or at a product loading of 1-1.3 g of the product per liter of the liquid for 12-25 hours in the liquid. For example, in one embodiment, such a product may have a PFAS removal efficiency of 70%-100% at a product loading of 0.5-2 g of the product per liter of the liquid for a contact time of about 12-25 hours in the liquid; in an improvement, such a product may have a PFAS removal efficiency of 80%-100% at a product loading of 0.5-2 g of the product per liter of the liquid for a contact time of about 12-25 hours in the liquid; in an improvement, such a product may have a PFAS removal efficiency of 90%-100% at a product loading of 0.5-2 g of the product per liter of the liquid for a contact time of about 12-25 hours in the liquid; in another improvement, such a product may have a PFAS removal efficiency of 95%-100% at a product loading of 0.5-2 g of the product per liter of the liquid for a contact time of about 12-25 hours in the liquid, or such a product may have a PFAS removal efficiency of 97%-100% at a product loading of 0.5-2 g of the product per liter of the liquid for a contact time of about 12-25 hours in the liquid.

[0038] In any one of the above embodiments, the surface-functionalized product containing attapulgite may have a total PFAS removal efficiency of 10-95%, 15-95% or 18-95% for multiple PFAS in the liquid at a product loading of 0.5-2 g of the product per liter of the liquid for a contact / mixing time of 12-25 hours in the liquid.

[0039] In any one or more of the above embodiments or improvements, the attapulgite or the product containing attapulgite is not acid-activated. In any one or more of the above embodiments or improvements, the attapulgite or the product may be free of residual acid (acid-free).

[0040] In any one or more of the above embodiments or improvements, the product is free of oleylamine and octylamine.

[0041] In another embodiment, the product contains sepiolite, and the weight percentages of the components of the product are as follows: 76 - 97 wt% sepiolite; 1 - 16 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 0.5 - 8 wt% of a surface coating agent containing one or more mercapto groups. When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain any di-quaternary amines. When the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain any mono-quaternary amines. The quaternary amine surface coating solution may further contain water. The mercapto surface coating solution may further contain a solvent.

[0042] Natural sepiolite (as the feedstock) may have a surface area in the range of 200 - 300 m 2 / g or 240 - 300 m 2 / g or 258 - 285 m 2 / g or 270 - 274 m 2 / g or about 272 m 2 / g, measured using the Brunauer-Emmett-Teller (BET) theory. In any one of the above embodiments, natural sepiolite (as the feedstock) has a d of 10 - 20 microns or 12 - 16 microns or 13 - 15 microns or about 14.2 microns 50It may have a particle size distribution. In any one of the above embodiments, natural sepiolite (as a feedstock) may have a porosity of 75 - 95% or 76 - 93% or 80 - 89% or about 84.5%. In any one of the above embodiments, natural sepiolite (as a feedstock) may have a pore volume of 2.5 - 4 mL / g or 3.1 - 3.8 mL / g or 3.2 - 3.6 mL / g or 3.3 - 3.5 mL / g or about 3.45 mL / g. In any one or more of the above embodiments or improvements, for natural sepiolite (as a feedstock), the intrinsic pores can be from about 8 nm to about 25 nm, and the peak position of the intrinsic pores can be in the range from about 12 nm to about 16 nm; and / or the internal pores can be from about 40 nm to about 4 microns, and the peak position of the internal pores can be in the range from about 1.2 microns to about 1.6 microns.

[0043] (Surface functionalization) The product (including sepiolite) may have a surface area in the range of 76 - 276 m 2 / g or 86 - 254 m 2 / g or 91 - 243 m 2 / g or about 96 - 231 m 2 / g as measured using the Brunauer - Emmett - Teller (BET) theory. In any one of the above embodiments, the product (e.g., sepiolite (after surface functionalization)) has a d 50It may have a particle size distribution. In any one of the above embodiments, such (surface-functionalized) products (including sepiolite) may have a porosity of about 62 - 86%, or about 65 - 82% or about 69 - 78%. In any one of the above embodiments, such (surface-functionalized) products (including sepiolite) may have a pore volume of 1.3 - 3.0 mL / g or 1.4 - 2.8 mL / g or about 1.5 - 2.7 mL / g. In any one or more of the above embodiments or improvements, for such (surface-functionalized) products (including sepiolite), the intrinsic pores can be from about 9 to about 28 nm, and the peak position of the intrinsic pores can be in the range from about 12 nm to about 19 nm; and / or the internal pores can be from about 540 nm to about 44 microns, and the peak position of the internal pores can be in the range from about 1.8 microns to about 32 microns. In the improvement, for such (surface-functionalized) products (including sepiolite), the intrinsic pores can be from about 10 to about 25 nm, and the peak position of the intrinsic pores can be in the range from about 14 nm to about 17 nm; and / or the internal pores can be from about 600 nm to about 40 microns, and the peak position of the internal pores can be in the range from about 2 microns to about 29 microns. In any one or more of the above embodiments, such (surface-functionalized) products (including sepiolite) can be in powder form or non-extruded form (not extruded before or after surface functionalization). In any one or more of the above embodiments, sepiolite can be the following: (a) natural sepiolite that may not have been heat-treated (at temperatures from above 300°C to about 1000°C) and / or fired (e.g., at temperatures above about 1000°C) before surface functionalization, or it can include them. In any one or more of the above embodiments, sepiolite may be in powder form. In any one or more of the above embodiments, sepiolite is not extruded (not extruded either before or after surface functionalization).

[0044] In any one of the above embodiments, the (surface-functionalized) product (including sepiolite) may have a PFAS removal efficiency of 70-100%, 80-100%, 90-100%, 95-100%, or 97-100% for PFAS in the liquid at a product loading of 0.5-2 g of product per liter of liquid, or at a product loading of 1-1.3 g of product per liter of liquid for 12-25 hours in the liquid. For example, in one embodiment, such a product may have a PFAS removal efficiency of 70%-100% at a product loading of 0.5-2 g of product per liter of liquid for a contact time of about 12-25 hours in the liquid; in an improvement, such a product may have a PFAS removal efficiency of 80%-100% at a product loading of 0.5-2 g of product per liter of liquid for a contact time of about 12-25 hours in the liquid; in an improvement, such a product may have a PFAS removal efficiency of 90%-100% at a product loading of 0.5-2 g of product per liter of liquid for a contact time of about 12-25 hours in the liquid; in another improvement, such a product may have a PFAS removal efficiency of 95%-100% at a contact time of about 12-25 hours in the liquid, or such a product may have a PFAS removal efficiency of 97%-100% at a product loading of 0.5-2 g of product per liter of liquid for a contact time of about 12-25 hours in the liquid.

[0045] In any one of the above embodiments, the (surface-functionalized) product (including sepiolite) may have a total PFAS removal efficiency of 10-100%, 15-100% or 18-100% for multiple PFAS in the liquid at a product loading of 0.5-2 g of product per liter of liquid for a contact / mixing time of 12-25 hours in the liquid.

[0046] In any one or more of the above embodiments or improvements, the sepiolite or product is not acid-activated. In any one or more of the above embodiments or improvements, the sepiolite or product may be acid-free (containing no residual acid).

[0047] In any one or more of the above embodiments or improvements, the product is free of oleylamine and octylamine and is in a free state.

[0048] Preparation of the Product The method for producing the products of Examples 1-12 discussed herein may include selecting attapulgite. Attapulgite / palygorskite is a magnesium aluminum layered silicate having the chemical formula (Mg, Al)2Si4O 10 (OH)·4H2O. The percentages of the various components can vary depending on the ore deposit where the attapulgite is produced. In any one or more of the above embodiments, the attapulgite can be natural attapulgite that has not been heat-treated (at 300°C - about 1000°C) or fired (e.g., at about 1000°C or higher) before surface functionalization, or it may contain them. The selected natural attapulgite, measured by the nitrogen adsorption method based on the Brunauer-Emmett-Teller (BET) theory, may have a large surface area in the range of 90m 2 / g - 160m 2 / g, and a particle size (d50) of 5 - 25 microns (measured by a laser particle size analyzer). In the improvement, the natural attapulgite, measured by the nitrogen adsorption method based on the Brunauer-Emmett-Teller (BET) theory respectively, is 120m 2 / g - 145m 2 / g, or 130m 2 / g - 145m 2It may have a surface area in the range of / g. In a further improvement, the particle size (d50) of the feedstock can be 6 - 18 microns, 8 - 17 microns or 10 - 15 microns as measured by a laser particle size analyzer. In each of the above embodiments and improvements, attapulgite (feedstock) may contain 7 - 16 wt% or 9 - 14 wt% moisture (when measured at 104 °C (220 °F)). Figures 1A and 1B are SEM images at magnifications of 25,000 times and 200,000 times of a feedstock containing natural attapulgite. As seen in Figures 1A and 1B, the feedstock may contain attapulgite, which may contain or consist of a plurality of rod-shaped attapulgite particles. Without wishing to be bound by theory, the inventors believe that such a moisture content of the attapulgite used as the feedstock may facilitate the binding or fixation of a surface coating agent containing one or more mercapto groups (e.g., mercaptosilane) to the attapulgite surface. For example, when the surface coating agent is mercaptosilane, the silane molecules are first hydrolyzed by trace amounts of water present on the surface of the attapulgite, and then covalent bond formation with the surface of the attapulgite follows.

[0049] The method includes mixing a quaternary amine compound and water to form a quaternary amine surface coating solution for coating the surface of attapulgite. In one embodiment, the quaternary amine compound may (or may consist of) a mono-quaternary amine compound, where the resulting quaternary amine surface coating solution from the mixing does not contain a di-quaternary amine. In another embodiment, the quaternary amine compound may (or may consist of) a di-quaternary amine compound, where the resulting quaternary amine surface coating solution from the mixing does not contain a mono-quaternary amine. In other words, in the quaternary amine surface coating solution, if one or more mono-quaternary amine compounds are present, no di-quaternary amine is present. Similarly, in the quaternary amine surface coating solution, if one or more di-quaternary amine compounds are present, no mono-quaternary amine is present.

[0050] In the various exemplary embodiments described herein, the quaternary amine surface coating solution was prepared by mixing 50 wt% of a mono - quaternary amine compound (e.g., 10 g of Kemira Superfloc C - 577) and 50 wt% of water (e.g., 10 g of deionized (DI) water) in a 100 mL (milliliter) glass beaker on a magnetic stir plate for about 10 minutes, although other mixing methods known in the art could have been utilized. The exemplary mono - quaternary amine compound utilized was Kemira Superfloc C - 577 [an ethylenediamine polymer containing (chloromethyl)oxirane and N - methylmethanamine in aqueous solution and having a concentration of about 50%]. In other words, the exemplary mono - quaternary amine compound contained about 50% quaternary amine. The resulting quaternary amine surface coating solution did not contain di - quaternary amine. In other embodiments, the quaternary amine surface coating solution may be prepared by mixing other suitable amounts of mono - quaternary amine compound(s) and water (e.g., deionized water). For example, the quaternary amine surface coating solution may contain 25 - 56 wt% of a mono - quaternary amine compound and 44 - 75 wt% of water (e.g., DI water), where the resulting quaternary amine surface coating solution does not contain di - quaternary amine. In other alternative embodiments described herein, the quaternary amine surface coating solution was prepared by mixing 50 wt% of a di - quaternary amine compound (e.g., 10 g of Evonik ADOGEN (R) (Evonik Adogen, (R) which is a registered trademark indication in the United States etc.) 477, N,N,N,N',N'-pentamethyl - N'-tallowalkyltrimethylenediammonium dichloride) and 50 wt% of water (e.g., 10 g of DI water) in a 100 mL glass beaker on a magnetic stir plate until well mixed (e.g., for about 10 minutes). The exemplary di - quaternary amine compound utilized (Evonik ADOGEN (R)477) contained approximately 50% di-quaternary amine. The resulting quaternary amine surface coating solution did not contain mono-quaternary amine. In other embodiments, the quaternary amine surface coating solution may contain other suitable amounts of di-quaternary amine compound(s) and water (e.g., DI water). For example, the quaternary amine surface coating solution may contain 33 - 60 wt% di-quaternary amine compound and 40 - 67 wt% water (e.g., DI water), where the resulting quaternary amine surface coating solution does not contain mono-quaternary amine.

[0051] The method further includes surface treating the attapulgite with a quaternary amine surface coating solution to functionalize the surface of the attapulgite. In one embodiment, the surface treatment may include spraying the quaternary amine surface coating solution onto the attapulgite or alternatively adding / applying the quaternary amine surface coating solution to the attapulgite and then mixing until the quaternary amine surface coating solution is well dispersed on the attapulgite. In the various embodiments described herein, the quaternary amine surface coating solution was sprayed onto the attapulgite and then the combination of the quaternary amine surface coating solution and the attapulgite was mixed until the quaternary amine surface coating solution was well dispersed throughout the attapulgite material. For example, in the various exemplary embodiments disclosed in the table herein, the quaternary amine surface coating solution was sprayed onto the attapulgite feedstock and then the mixture was mixed at low speed for about 30 minutes with a KitchenAid 5 - quart hood mixer. In embodiments other than the exemplary embodiments, other suitable amounts of the quaternary amine surface coating solution with respect to the attapulgite may be utilized to surface functionalize the attapulgite. Figure 2 schematically illustrates the surface functionalization of the feedstock (including natural attapulgite) with the quaternary amine surface coating solution. The quaternary amine(s) of the quaternary amine surface coating solution adhere to the surface of the attapulgite of the feedstock.

[0052] The method further includes mixing a solvent and a surface coating agent to form a mercapto surface coating solution for surface coating of attapulgite. The surface coating agent includes one or more mercapto groups. For example, in one embodiment, the surface coating agent may include one or more mercapto groups and silane. In the exemplary embodiments described herein, the mercapto surface coating solution is prepared by mixing 20% by weight of the surface coating agent (e.g., 5 g of gamma-mercaptopropyltrimethoxysilane (Momentive Silquest A-189)) and 80% by weight of the solvent (e.g., 20 g of ethanol) until well mixed (e.g., for about 10 minutes in a 100 mL glass beaker on a magnetic stirring plate), although other mixing methods known in the art may be utilized). In other embodiments, the mercapto surface coating solution may include other suitable amounts of the surface coating agent and the solvent. For example, the mercapto surface coating solution may include about 5-20% by weight of the surface coating agent and about 95-80% by weight of the solvent.

[0053] The method further includes surface treating the attapulgite with the mercapto surface coating solution to surface functionalize the attapulgite. In one embodiment, the attapulgite surface functionalized with the mercapto surface coating solution may already be surface functionalized with a quaternary amine surface coating solution. Figure 2 schematically illustrates the surface functionalization of attapulgite with the mercapto surface coating solution. In the embodiment shown in Figure 2, the quaternary amine(s) of the quaternary amine surface coating solution are attached to the surface of the feedstock attapulgite prior to surface functionalization with the mercapto surface coating solution. The mercapto groups of the mercapto surface coating solution chemically bond to the surface of the feedstock attapulgite.

[0054] In one embodiment, the surface treatment may include spraying the mercapto surface coating solution onto the attapulgite or alternatively adding the mercapto surface coating solution to the attapulgite and then mixing until the mercapto surface coating solution is well dispersed on the attapulgite. In the various embodiments described herein, the mercapto surface coating solution was sprayed onto the attapulgite (which had been pre-surface functionalized with a quaternary amine surface coating solution) and then mixed until the mercapto surface coating solution was well dispersed throughout the attapulgite. For example, in the various embodiments herein, the mercapto surface coating solution was sprayed onto the attapulgite material and the combination was then mixed at low speed in a KitchenAid 5 - quart hood mixer for about 30 minutes. In an exemplary embodiment herein, after spraying / adding / applying the quaternary amine surface coating solution (which contains water (e.g., DI water) and either a mono - quaternary amine compound or a di - quaternary amine compound) onto the attapulgite, the mercapto surface coating solution was sprayed / added / applied onto the attapulgite. The inventors have found that when the attapulgite feed material is first treated with the quaternary amine surface coating solution and subsequently treated with the mercapto surface coating solution, the water (e.g., deionized water) in the quaternary amine surface coating solution promotes the mercaptosilane hydrolysis reaction and the formation of Si - O - Si - SH bonds on the attapulgite surface, such that the mercapto groups are substantially immobilized on the attapulgite surface.

[0055] This method may further include the following: treating the attapulgite with a quaternary amine surface coating solution and a mercapto surface coating solution, and then drying the surface-treated attapulgite (twice) in an oven or the like (at about 60 - 70 °C) for about 4 - 6 hours, or until the attapulgite is dry (both surface coating solutions are dry on the surface of the attapulgite particles). In the above embodiment, after mixing, the mixture was dried in an oven at 60 - 70 °C for about 4 hours. In some embodiments, the resulting product may be in powder form or in a non-extruded (not processed by extrusion) form. In some embodiments, the attapulgite particles of the resulting product may exhibit a generally rounded granular shape. In other embodiments, the attapulgite particles of the resulting product may exhibit an irregular shape. As described above, in one embodiment, the attapulgite may be composed of a plurality of rod-shaped attapulgite particles. After surface coating and drying, the quaternary amine(s) adhere to the attapulgite surface and the mercapto groups chemically bond to the attapulgite surface.

[0056] The surface coating agent may include (or may be) the following: mercaptosilane(s) or non-silane mercaptothiol compound(s), or a mixture thereof. Mercaptosilanes include, but are not limited to, the following: 3-mercaptopropyltrimethoxysilane; 3-(mercaptopropyl)triethoxysilane; 3-mercaptopropylmethyldimethoxysilane; (mercaptomethyl)dimethylethoxysilane; (mercaptomethyl)methyldiethoxysilane; 3-mercaptomethyltrimethoxysilane; 3-mercaptomethyltriethoxysilane; 11-mercaptoundecyltrimethoxysilane; or a mixture thereof. Non-silane mercaptothiol compounds include, but are not limited to, the following: 3-mercapto-1,2-propanediol; mercaptobenzothiazole; ethanethiol; 1-butanethiol; 1-propanethiol; cyclopentanethiol; or a mixture thereof. The foregoing list is exemplary. Mercaptosilanes are not limited to such listed examples. Non-silane mercaptothiol compounds are not limited to the listed examples. The solvent may include, or may be, methanol, ethanol, isopropanol, chloroform, toluene, or a mixture thereof. In one embodiment, the mercapto surface coating solution may include, or may be, gamma-mercaptopropyltrimethoxysilane and ethanol.

[0057] In the surface area measurement before and after surface-treating attapulgite with a solution, it is shown that the surface area decreases after treatment with a quaternary amine surface coating solution and a mercapto surface coating solution (see, for example, Table 5).

[0058] Similarly to the above, the method for producing the products of Examples 13-18 described herein may include selecting sepiolite. Sepiolite has the chemical formula Mg4Si6O 15It is magnesium silicate hydrate with (OH)2·6H2O. The percentages of various components can vary depending on the ore deposit where sepiolite is produced. In any one or more of the above embodiments, sepiolite can be natural sepiolite that has not been heat-treated (from about 300 °C to about 1000 °C) and has not been calcined (e.g., at about 1000 °C or higher) before surface functionalization, or it may contain them. The selected natural sepiolite, measured by the nitrogen adsorption method based on the Brunauer-Emmett-Teller (BET) theory, may have a large surface area in the range of 200 m 2 / g - 300 m 2 / g and a particle size (d50) of 10 - 20 microns (measured with a laser particle size analyzer). In the improvement, natural sepiolite, measured by the nitrogen adsorption method based on the Brunauer-Emmett-Teller (BET) theory respectively, is 240 m 2 / g - 300 m 2 / g or 258 m 2 / g - 285 m 2 / g, or 270 m 2 / g - 274 m 2It may have a surface area in the range of / g. In a further improvement, the particle size (d50) of the feedstock can be measured by a laser particle size analyzer and be 12 - 16 microns, or 13 - 15 microns, or about 14.2 microns. In each of the above embodiments and improvements, the sepiolite (feedstock) may have a loss on ignition of 16 - 22% moisture and a loss on drying of 5 - 10% moisture. The drying of moisture can be measured at around about 100°C. In each of the above embodiments and improvements, the natural sepiolite (as the feedstock) may have a porosity of 75 - 95% or 76 - 93%, or 80 - 89% or about 84.5%. In each of the above embodiments and improvements, the natural sepiolite (as the feedstock) may have a pore volume of 2.5 - 4 mL / g or 3.1 - 3.8 mL / g or 3.2 - 3.6 mL / g or 3.3 - 3.5 mL / g or about 3.45 mL / g. For natural sepiolite (as the feedstock), the intrinsic pores can be from about 8 nm to about 25 nm in one embodiment, and the peak position of the intrinsic pores can be in the range from about 12 nm to about 16 nm; and / or the internal pores can be from about 40 nm to about 4 microns, and the peak position of the internal pores can be in the range from about 1.2 microns to about 1.6 microns. FIG. 12 is a SEM image at a magnification of 10,000 times of the feedstock containing natural sepiolite. As can be seen from FIG. 12, the feedstock can contain sepiolite or can be sepiolite, which can contain or can be a plurality of fibrous sepiolite particles. Without wishing to be bound by theory, the inventors believe that such moisture content and morphology of the sepiolite used as the feedstock can facilitate the binding or fixation of a surface coating agent containing one or more mercapto groups (e.g., mercaptosilane) to the sepiolite surface. For example, when the surface coating agent is mercaptosilane, the silane molecules can first be hydrolyzed by trace amounts of water present on the surface of the sepiolite, and then the formation of covalent bonds with the sepiolite surface follows.

[0059] This method involves mixing a quaternary amine compound and water to form a quaternary amine surface coating solution for the surface coating of sepiolite. In one embodiment, the quaternary amine compound may (or may) include a mono - quaternary amine compound, and the resulting quaternary amine surface coating solution from the mixing does not contain a di - quaternary amine. In another embodiment, the quaternary amine compound may (or may) include a di - quaternary amine compound, and the resulting quaternary amine surface coating solution from the mixing does not contain a mono - quaternary amine. In other words, in the quaternary amine surface coating solution, when one or more mono - quaternary amine compounds are present, the di - quaternary amine is not present. Similarly, in the quaternary amine surface coating solution, when one or more di - quaternary amine compounds are present, the mono - quaternary amine is not present.

[0060] In various exemplary embodiments described herein, the quaternary amine surface coating solution was prepared by mixing 50 wt% of a mono - quaternary amine compound (e.g., 10 g of Kemira Superfloc C - 577) and 50 wt% of water (e.g., 10 g of deionized water (DI)) in a 100 mL glass beaker on a magnetic stir plate for about 10 minutes, although other mixing methods known in the art could have been utilized. The exemplary mono - quaternary amine compound utilized was Kemira Superfloc C - 577 [aqueous solution of 1,2 - ethanediamine polymer having (chloromethyl)oxirane and N - methylmethanamine, having a concentration of about 50%]. In other words, the exemplary mono - quaternary amine compound contained about 50% quaternary amine. The resulting quaternary amine surface coating solution did not contain di - quaternary amine. In other embodiments, the quaternary amine surface coating solution may be prepared by mixing other suitable amounts of mono - quaternary amine compound(s) and water (e.g., DI water). For example, the quaternary amine surface coating solution may contain 25 - 56 wt% of a mono - quaternary amine compound and 44 - 75 wt% of water (e.g., DI water), and the resulting quaternary amine surface coating solution does not contain di - quaternary amine. In other alternative embodiments described herein, the quaternary amine surface coating solution was prepared by mixing 50 wt% of a di - quaternary amine compound (e.g., 10 g of Evonik ADOGEN (R) 477, N,N,N,N',N' - pentamethyl - N' - tall oil alkyltrimethylenediammonium dichloride, having a concentration of about 50%) and 50 wt% of water (e.g., 10 g of DI water) in a 100 mL glass beaker on a magnetic stir plate until well mixed (e.g., for about 10 minutes). The exemplary di - quaternary amine compound utilized (Evonik ADOGEN (R)(477) contained approximately 50% di-quaternary amine. The resulting quaternary amine surface coating solution did not contain mono-quaternary amine. In other embodiments, the quaternary amine surface coating solution may contain other suitable amounts of di-quaternary amine compound(s) and water (e.g., DI water). For example, the quaternary amine surface coating solution may contain 33 - 60 wt% di-quaternary amine compound and 40 - 67 wt% water (e.g., DI water), where the resulting quaternary amine surface coating solution does not contain mono-quaternary amine.

[0061] The method further includes surface treating the sepiolite with a quaternary amine surface coating solution to surface functionalize the sepiolite. In one embodiment, the surface treatment may include spraying the quaternary amine surface coating solution onto the sepiolite, or alternatively adding / applying the quaternary amine surface coating solution to the sepiolite, and then mixing until the quaternary amine surface coating solution is well dispersed over the sepiolite. In the various embodiments described herein, the quaternary amine surface coating solution was sprayed onto the sepiolite, and then the combination of the quaternary amine surface coating solution and the sepiolite was mixed until the quaternary amine surface coating solution was well dispersed throughout the sepiolite material. For example, in the various exemplary embodiments disclosed in the tables herein, the quaternary amine surface coating solution was sprayed onto the sepiolite feed material, and the combination was then mixed in a KitchenAid 5 - quart hood mixer at low speed for about 30 minutes. In the surface functionalization of the feed material (including natural sepiolite) with the quaternary amine surface coating solution, the quaternary amine(s) of the quaternary amine surface coating solution adhere to the surface of the sepiolite of the feed material. In other embodiments, other suitable amounts of the quaternary amine surface coating solution with respect to the sepiolite may be utilized to surface functionalize the sepiolite.

[0062] This method further includes mixing a solvent and a surface coating agent to form a mercapto surface coating solution for the surface coating of sepiolite. The surface coating agent contains one or more mercapto groups. For example, in one embodiment, the surface coating agent may contain one or more mercapto groups and silane. In various exemplary embodiments described herein, the mercapto surface coating solution is prepared by mixing 20 wt% of the surface coating agent (e.g., 5 g of gamma-mercaptopropyltrimethoxysilane (Momentive Silquest A-189)) and 80 wt% of the solvent (e.g., 20 g of ethanol) until well mixed (e.g., for about 10 minutes in a 100 mL glass beaker on a magnetic stirring plate), although other mixing methods known in the art could have been utilized). In other embodiments, the mercapto surface coating solution may contain other suitable amounts of the surface coating agent and the solvent. For example, the mercapto surface coating solution may contain about 5-20 wt% of the surface coating agent and about 95-80 wt% of the solvent.

[0063] This method further includes treating the surface of sepiolite with the mercapto surface coating solution to surface-functionalize the sepiolite. In one embodiment, the sepiolite surface-functionalized with the mercapto surface coating solution may already be surface-functionalized with a quaternary amine surface coating solution. Similar to what is shown in FIG. 2 for attapulgite, the quaternary amine(s) of the quaternary amine surface coating solution adhere to the surface of the feed sepiolite prior to surface-functionalization with the mercapto surface coating solution. The mercapto groups of the mercapto surface coating solution chemically bond to the surface of the feed sepiolite.

[0064] In one embodiment, the surface treatment can include spraying a mercapto surface coating solution onto the sepiolite, or alternatively adding the mercapto surface coating solution to the sepiolite, and then mixing until the mercapto surface coating solution is well dispersed on the sepiolite. In the various embodiments described herein, the mercapto surface coating solution was sprayed onto sepiolite (previously surface-functionalized with a quaternary amine surface coating solution), and then the combination was mixed until the mercapto surface coating solution was well dispersed throughout the sepiolite. For example, in the various exemplary embodiments herein, the mercapto surface coating solution was sprayed onto the sepiolite material, and the combination was then mixed at low speed in a KitchenAid 5 - quart hood mixer for about 30 minutes. In other embodiments, other suitable amounts of the mercapto surface coating solution relative to the sepiolite can be utilized to surface - functionalize the sepiolite. In one embodiment, the mercapto surface coating solution is sprayed / added / applied onto the sepiolite following spraying / adding / applying of a quaternary amine surface coating solution (which includes water (e.g., DI water) and either a mono - quaternary amine compound or a di - quaternary amine compound) onto the sepiolite. The inventors have found that when the sepiolite feed material is first treated with the quaternary amine surface coating solution and subsequently treated with the mercapto surface coating solution, the water (e.g., DI water) in the quaternary amine surface coating solution promotes the mercaptosilane hydrolysis reaction and the formation of Si - O - Si - SH bonds on the sepiolite surface, substantially fixing the mercapto groups to the sepiolite surface.

[0065] This method can further include, after surface-treating sepiolite with a quaternary amine surface coating solution and a mercapto surface coating solution, drying the surface-treated sepiolite (twice) in an oven or something of that kind (at about 60 - 70 °C) for about 4 - 6 hours, or until the sepiolite dries (both surface coating solutions dry on the surface of the sepiolite particles). In the above embodiment, after mixing, the mixture was dried in an oven at 60 - 70 °C for about 4 hours. In some embodiments, the product produced may be in powder form or in a non-extruded (not extruded) form. In some embodiments, some or substantially all of the sepiolite particles of the resulting product may be in the form of fibrous particles. After surface coating and drying, the quaternary amine(s) adhere to the sepiolite surface and the mercapto groups chemically bond to the sepiolite surface.

[0066] The surface coating agent may include, or may be, the following: mercaptosilane(s) or non-silane mercaptothiol compound(s), or a mixture thereof. Mercaptosilanes may include, but are not limited to, the following: 3-mercaptopropyltrimethoxysilane; 3-(mercaptopropyl)triethoxysilane; 3-mercaptopropylmethyldimethoxysilane; (mercaptomethyl)dimethylethoxysilane; (mercaptomethyl)methyldiethoxysilane; 3-mercaptomethyltrimethoxysilane; 3-mercaptomethyltriethoxysilane, 11-mercaptoundecyltrimethoxysilane; or a mixture thereof. Non-silane mercaptothiol compounds may include, but are not limited to, the following: 3-mercapto-1,2-propanediol, mercaptobenzothiazole, ethanethiol, 1-butanethiol, 1-propanethiol, cyclopentanethiol; or a mixture thereof. The foregoing list is exemplary. Mercaptosilanes are not limited to such listed examples. Non-silane mercaptothiol compounds are not limited to the listed examples. The solvent may include, or may be, methanol, ethanol, isopropanol, chloroform, toluene, or a mixture thereof. In one embodiment, the mercapto surface coating solution may include, or may be, gamma-mercaptopropyltrimethoxysilane and ethanol.

[0067] In the measurement of the surface area before and after surface treatment of sepiolite with a solution, it is shown that the surface area decreases after treatment with a quaternary amine surface coating solution and a mercapto surface coating solution (see, for example, Table 5).

[0068] In the method disclosed herein, the feed material may include, or may be, attapulgite, or sepiolite, or attapulgite and sepiolite, or may be them.

[0069] Explanation of the Test Method Surface Area, Pore Volume, Pore Size Distribution, Porosity The surface area was measured by the nitrogen adsorption method of the BET (Brunauer-Emmett-Teller) method. The pore volume and pore size distribution of the material sample were measured by mercury porosimetry. Mercury porosimetry uses mercury as the intrusion fluid to measure the pore volume of a (weight-measured) material sample enclosed in the sample chamber of a penetrometer. The sample chamber evacuates air to remove the air of the sample from the pores. The sample chamber and the penetrometer are filled with mercury. Since mercury does not wet the surface of the material, it needs to be pushed into the pores by an external pressure. A gradually increasing pressure is applied so that mercury enters the pores. The equilibrium pressure required is inversely proportional to the pore size. Only a small pressure is required to make mercury invade macropores, but a much larger external pressure is required to push mercury into small pores. The penetrometer reads the volume of the intruded mercury and uses the intrusion data to calculate the pore size distribution, porosity, average pore size, and total pore volume. Micromeritics AutoPore IV 9500 was used for the analysis of the sample here.

[0070] Assuming cylindrical pores, the surface distribution can be derived from the pore volume distribution for use in calculations. An estimate of the total surface area of the material sample can be made from the pressure / volume curve (Rootare, 1967) without using a pore model as follows [Equation] as follows. where A = total surface area γ = surface tension of mercury θ = contact angle between mercury and the pore wall of the material p = externally applied pressure V = pore volume From the function V = V(p), the integration can be calculated by a numerical method.

[0071] From the relationship between the pressure and the mercury intrusion data, the apparatus is as follows: [Equation] Generate the pore volume and size distribution according to the Washburn equation (Washburn, 1921) as follows. In the equation, d i = pore diameter at equilibrium external pressure γ = surface tension of mercury θ = contact angle between mercury and the pore wall of the material P i = externally applied pressure

[0072] The average pore diameter is determined from the cumulative intrusion volume and the total surface area of the material sample as follows:

Equation

[0073] Porosity is the ratio of the total volume of the material occupied by the pore space. Porosity is calculated from mercury intrusion data. EPA Method 533 (Determination of Perfluoroalkyl and Polyfluoroalkyl Substances in Drinking Water by Isotope Dilution Anion Exchange Solid Phase Extraction and Liquid Chromatography / Tandem Mass Spectrometry)

[0074] Samples of 100 - 250 mL are fortified with an analog labeled with the isotope of the analyte of the method that functions as an isotope dilution standard. The sample is passed through a solid-phase extraction (SPE) cartridge containing polystyrene divinylbenzene with a positively charged diamino ligand such that the analyte and isotope dilution analog of the method are extracted. The cartridge is rinsed with a continuous wash of aqueous ammonium acetate, followed by methanol, and then the compounds are eluted from the solid-phase adsorbent with methanol containing ammonium hydroxide. The extract is concentrated to dryness using nitrogen in a heated water bath. The volume of the extract is adjusted to 1.0 mL with 20% water (v / v) in methanol, and three isotope performance standards labeled with isotopes are added. The extract is analyzed by liquid chromatography-tandem mass spectrometry (LC-MS / MS) in multiple reaction monitoring (MRM) detection mode. The concentration of each analyte is calculated using the isotope dilution method. For quality control (QC) purposes, the percent recovery of the isotope dilution analog is calculated using the integrated peak areas of the isotope performance standards, which are added to the final extract and function as traditional internal standards, applied exclusively to the isotope dilution analog.

[0075] EPA Method SW846 Method 3535A: Solid Phase Extraction (SPE) The sample preparation procedure varies by analyte group. For the extraction of some analyte groups, the pH of the sample is adjusted to a specified value prior to extraction. In other groups, pH adjustment is not required. After the necessary pH adjustment, the measured volume of the sample is extracted by passing it through a solid-phase extraction medium (disk or cartridge), which is held in an extraction device designed for vacuum filtration of the sample. The target analyte is eluted from the solid-phase medium using an appropriate solvent and collected in a receiving vessel. The resulting solvent extract is dried using sodium sulfate and, if necessary, concentrated. Depending on the requirements of a particular analysis, the concentrated extract may be exchanged for an extract compatible with the solvent, and then a cleanup procedure or measurement procedure may be performed for the measurement of the target analyte. Loss on Ignition (LOI) Loss on ignition (LOI) can be used to measure the water of hydration in a sample of the feed material. Such an LOI test needs to be carried out at a high temperature (e.g., 980 °C - 1200 °C, preferably 982 °C - 1000 °C) for a sufficient time (at least 1 hour) so that the chemically bound water has the opportunity to dissociate and volatilize. By accurately measuring the sample mass (up to nearly 0.1 mg) before and after this treatment, quantification of the water of hydration becomes possible.

Example

[0076] The products of Examples 1 - 12 each contain attapulgite. The products of Examples 1 - 12 were prepared from the natural attapulgite feed materials listed in Table 1.

Table 1

[0077] The natural attapulgite feed materials were prepared using natural attapulgite mined near Climax, Georgia, by Active Minerals International, LLC (Active Minerals International). The main component composition of this natural attapulgite feed material, as determined by wavelength-dispersive XRF analysis, is shown in Table 2.

Table 2

[0078] The feed material containing natural attapulgite had a large surface area of approximately 141 m 2 / g as measured by the nitrogen adsorption method based on the Brunauer-Emmett-Teller (BET) theory. The particle size (d 50) was around 13.49 microns (μm) as measured by a laser particle size analyzer. The natural attapulgite feed material was in powder form and had not been extruded. The natural attapulgite feed material had not been heat treated (at temperatures from about 300 °C to about 1000 °C) and / or fired (e.g., at temperatures above about 1000 °C). In any one or more embodiments herein, the attapulgite utilized may be in powder form.

[0079] The natural attapulgite feed material contains about 7 - 16 wt% or about 9 - 14 wt% moisture (at 104 °C (220 °F)). Without being bound by theory, the inventors believe that such moisture promotes the binding of a surface coating agent (e.g., mercaptosilane) to the attapulgite surface. For example, when the surface coating agent contains or is mercaptosilane, it is thought that the silane molecules can first be hydrolyzed by trace amounts of water present on the surface of the attapulgite, and then covalent bond formation with the attapulgite surface can follow.

[0080] Tables 3A - 3B show that Examples 1 - 12 were prepared from the natural attapulgite feed material using a surface functionalization treatment. In Tables 3A - 3B, the weight percentage of the surface coating agent (e.g., mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent. More specifically, for the mercapto surface coating solution, the solvent portion (e.g., ethanol) that evaporates upon drying is not included in the weight of the resulting adsorbent for the calculations in Table 3B. Similarly, in Tables 3A - 3B, the weight percentage of the quaternary amine (e.g., about 50% of the weight of the quaternary amine compound used) is defined as a percentage of the weight of the resulting adsorbent. For the amine surface coating solution, the DI water portion (which evaporates during drying) in which the quaternary amine compound is dispersed is not included in the weight of the resulting adsorbent for the calculations in Table 3B.

[0081] As an example, in Example 1, 5 g of mercaptosilane is 5 wt% of the total weight of the resulting adsorbent of 100 g (5 g of mercaptosilane plus 95 g of attapulgite). In Example 3, 4.73 g of mercaptosilane is 4.7 wt% of the total weight of the adsorbent of 99.73 g (4.73 g of mercaptosilane + 5 g of quaternary amine + 90 g of attapulgite), and 5 g of quaternary amine is 5 wt% of the total weight of the resulting adsorbent of 99.73 g. For clarity, in Example 3, 10 g of the mono - quaternary compound was used, of which 50% (5 g) was the quaternary amine. The weight percentage of the quaternary amine in DI water is calculated as follows: [weight of quaternary amine / (weight of quaternary amine + weight of DI water)] * 100). Similarly, the weight percentage of mercapto in the solvent is calculated as follows: [weight of mercaptosilane / (weight of mercaptosilane + weight of solvent)] * 100.

Table 3A

Table 3B

[0082] Example 1 was prepared using a mercaptosilane surface functionalization treatment. The mercapto surface coating solution for the surface coating of natural attapulgite was prepared by mixing 5 g of the surface coating agent [gamma - mercaptopropyltrimethoxysilane (Momentive Silquest A - 189)] with 20 g of the solvent (ethanol) for 10 minutes in a 100 mL glass beaker on a magnetic stirring plate. 95 g of the attapulgite feedstock was mixed with 25 g of the mercapto surface coating solution in a KitchenAid 5 - quart hood mixer. After mixing at low speed for 30 minutes, the mixture was dried in an oven at 60 - 70 °C for 4 hours. Example 2

[0083] Example 2 was prepared using a quaternary amine surface functionalization treatment. The quaternary amine surface coating solution for the surface coating of attapulgite was prepared by mixing 10 g of Kemira Superfloc C-577 (a mono-quaternary amine compound, a 1,2-ethanediamine polymer) with 10 g of DI water in a 100 mL glass beaker on a magnetic stirring plate for 10 minutes (with (chloromethyl)oxirane and N-methylmethanamine). The weight of the mono-quaternary amine in the exemplary mono-quaternary compound (Kemira Superfloc C-577) is estimated to be about 50% of the total weight of the Kemira Superfloc C-577 solution. By itself, in Example 2, the mono-quaternary amine compound (Kemira Superfloc C-577) contained about 5 g of mono-quaternary amine. 90 g of the attapulgite feedstock was mixed with 20 g of the quaternary amine surface coating solution in a KitchenAid 5-quart hood mixer. After mixing at low speed for 30 minutes, the mixture was dried in an oven at 60 - 70 °C for 4 hours. Examples 3 - 9

[0084] Examples 3 - 9 were prepared using a dual surface treatment with a quaternary amine surface coating solution and a mercapto surface coating solution. Tables 3A - 3B show the various loading levels utilized for the quaternary amine surface coating solution and for the mercapto surface coating solution to study the effect of PFAS affinity functional groups on PFAS removal.

[0085] As described above, the quaternary amine surface coating solution contains a quaternary amine compound and water (the quaternary amine compound is dispersed in DI water). In Examples 3-9, the quaternary amine surface coating solution for the surface coating of attapulgite was prepared by mixing Kemira Superfloc C-577 in deionized water in a 100 mL glass beaker on a magnetic stirring plate for 10 minutes with a mono-quaternary amine compound, 1,2-ethanediamine polymer (with (chloromethyl)oxirane and N-methylmethanamine). Then, the attapulgite feedstock was mixed with the quaternary amine surface coating solution in a KitchenAid 5-quart hood mixer at low speed for about 30 minutes. In Examples 3-9, since the quaternary amine compound contained (or was) a mono-quaternary amine compound, the quaternary amine surface coating solutions of Examples 3-9 each contained a mono-quaternary amine compound and DI water. The mono-quaternary amine in the exemplary mono-quaternary compound (Kemira Superfloc C-577) is estimated to be about 50% of the total weight of the Kemira Superfloc C-577 solution used. Further, each of the quaternary amine surface coating solutions of Examples 3-9 did not contain a di-quaternary amine and also did not contain oleylamine and octylamine.

[0086] As can be seen from Tables 3A-3B, in Examples 3-9, various loading levels of the surface coating agent and the solvent were utilized for the mercapto surface coating solution. As described above, the mercapto surface coating solution contains a surface coating agent and a solvent. The surface coating agent contains one or more mercapto groups. In Examples 3-9, the surface coating agent contained a silane and one or more mercapto groups. The surface coating agent is referred to as "mercaptosilane" in Tables 3A-3B. In each of Examples 3-9, the surface coating agent utilized was gamma-mercaptopropyltrimethoxysilane (Momentive Silquest A-189), and the solvent was ethanol.

[0087] In Example 3-9, the mercapto surface coating solution for surface coating attapulgite was prepared by mixing a surface coating agent (mercaptosilane) in a solvent (ethanol) for 10 minutes in a 100 mL glass beaker on a magnetic stirrer plate. Next, an attapulgite feedstock, which was surface-functionalized with a quaternary amine surface coating solution, was mixed with the mercapto surface coating solution in a KitchenAid 5-quart hood mixer. After mixing at low speed for 30 minutes, the mixture was dried in an oven at 60 - 70 °C for 4 hours. The resulting adsorbent was in powder form, not extruded, not acid-activated, and free of residual acid (acid-free).

[0088] Table 4 lists the pore volume, porosity, and particle size distribution (psd) of the attapulgite feedstock and Examples 4 and 7, and the sepiolite feedstock and Examples 13 - 18.

Table 4

[0089] Examples 10 through 12 were prepared using the same dual surface treatment and drying as Examples 3 through 9, except that each quaternary amine compound was composed of a di - quaternary amine compound, and thus the quaternary amine surface coating solutions of Examples 10 - 12 each contained a di - quaternary amine compound and DI water. More specifically, in Examples 10 - 12, the quaternary amine surface coating solution for surface coating attapulgite was prepared by mixing Evonik ADOGEN (R) 477, N,N,N,N',N'-pentamethyl-N'-tallow alkyltrimethylenediammonium dichloride (di - quaternary amine compound) in DI water for 10 minutes in a 100 mL glass beaker on a magnetic stir plate. A typical di - quaternary compound (Evonik ADOGEN (R)The weight of the two quaternary amines in (R) 477) is estimated to be about 50% of the total weight of the Evonik ADOGEN

[0090] The products of Examples 13 - 18 each contain sepiolite. The products of Examples 13 - 18 were prepared from the sepiolite feed materials listed in Table 1.

[0091] The feed materials for Examples 13 - 18 were prepared using natural sepiolite obtained from Sigma - Aldrich. The natural sepiolite contained about 13 wt% magnesium (Mg).

[0092] The feed materials utilized had a large surface area of about 272 m 2 / g as measured by the nitrogen adsorption method based on the Brunauer - Emmett - Teller (BET) theory. The particle size (d 50 ) of this feed material was about 14.2 microns as measured by a laser particle size analyzer. The sepiolite feed material was in powder form and had not been extrusion - processed. The natural sepiolite feed material had not been heat - treated (at temperatures from about 300 °C to about 1000 °C) and / or calcined (e.g., at temperatures above about 1000 °C).

[0093] The feedstock contains about 16 - 22 wt% moisture (as determined by loss on ignition). Without being bound by theory, the inventors believe that such moisture promotes the binding of surface coating agents (such as mercaptosilane) to the surface of sepiolite. For example, when the surface coating agent contains or is mercaptosilane, it can first be hydrolyzed by trace amounts of water present on the surface of sepiolite, and then the formation of covalent bonds with the sepiolite surface is thought to follow.

[0094] Tables 3A - 3B show that Examples 13 - 18 were prepared from natural sepiolite feedstock using surface functionalization treatments. In Tables 3A - 3B, the weight percentage of the surface coating agent (example is mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent. More specifically, for the mercapto surface coating solution, the portion of the solvent (example is ethanol) that evaporates upon drying is not included in the weight of the resulting adsorbent in the calculations of Table 3B. Similarly, in Tables 3A - 3B, the weight percentage of the quaternary amine (about 50% of the weight of the quaternary amine compound included (example is the weight of the quaternary amine compound used)) is defined as a percentage of the weight of the resulting adsorbent. For the amine surface coating solution, the portion of DI water in which the quaternary amine compound is dispersed (which evaporates during drying) is not included in the weight of the resulting adsorbent in the calculations of Table 3B.

[0095] As an example, in Example 13, 1 g of mercaptosilane is 1 wt% of the total adsorbent weight of 97.5 g (1 g of mercaptosilane + 2.5 g of quaternary amine + 94 g of sepiolite), and 2.5 g of the quaternary amine is 3 wt% of the total resulting adsorbent weight of 97.5 g. For clarity, in Example 13, 5 g of the di - quaternary compound was used, 50% (2.5 g) of which was the quaternary amine.

[0096] The weight percentage of the quaternary amine in DI water is calculated as follows: [weight of quaternary amine / (weight of quaternary amine + weight of DI water)] * 100. Similarly, the weight percentage of mercapto in the solvent is calculated as [weight of mercaptosilane / (weight of mercaptosilane + weight of solvent)] * 100. Examples 13 - 15

[0097] For each of Examples 13 to 15, it was prepared using a double surface treatment with a quaternary amine surface coating solution and a mercapto surface coating solution. Tables 3A - 3B show the various loading levels utilized for the quaternary amine surface coating solution and for the mercapto surface coating solution to examine the effect of the PFAS affinity functional group on PFAS removal.

[0098] As described above, the quaternary amine surface coating solution contains a quaternary amine compound and water (the quaternary amine compound is dispersed in deionized water). Examples 13 - 15 were prepared using double surface treatment and drying as in Examples 10 to 12. Each quaternary amine compound contains a di - quaternary amine compound, and thus, the quaternary amine surface coating solutions of Examples 13 - 15 each contained a di - quaternary amine compound and DI water. More specifically, in Examples 13 - 15, the quaternary amine surface coating solution for the surface coating of attapulgite was Evonik ADOGEN (R) 477, N,N,N',N'-pentamethyl - N'-tallowalkyltrimethylenediammonium dichloride (di - quaternary amine compound) was prepared by mixing in DI water for 10 minutes in a 100 mL glass beaker on a magnetic stir plate. The weight of the di - quaternary amine in a typical di - quaternary compound (Evonik ADOGEN (R) 477) was the weight of the Evonik ADOGEN used (R)It is estimated to be about 50% of the total weight of the 477 solution. The sepiolite feedstock was then mixed with the quaternary amine surface coating solution at low speed for about 30 minutes in a KitchenAid 5 - quart hood mixer. Each of the quaternary amine surface coating solutions of Examples 13 - 15 contained no mono - quaternary amine(s), nor oleylamine, nor octylamine. Thereafter, the amine surface - functionalized sepiolite was further surface - functionalized with a mercapto surface coating solution.

[0099] As can be seen from Tables 3A - 3B, in Examples 13 - 15, various loading levels of the surface coating agent and solvent were utilized for the mercapto surface coating solution. As described above, the mercapto surface coating solution contains a surface coating agent and a solvent. The surface coating agent contains one or more mercapto groups. In Examples 13 - 15, the surface coating agent contained silane and one or more mercapto groups. The surface coating agent is referred to as "mercaptosilane" in Tables 3A - 3B. In each of Examples 13 - 15, the surface coating agent utilized was gamma - mercaptopropyltrimethoxysilane (Momentive Silquest A - 189), and the solvent was ethanol.

[0100] In Examples 13 - 15, the mercapto surface coating solution for the surface coating of sepiolite was prepared by mixing the surface coating agent (mercaptosilane) with the solvent (ethanol) for 10 minutes in a 100 mL glass beaker on a magnetic stir plate. The sepiolite feedstock surface - functionalized with the quaternary amine surface coating solution was then mixed with the mercapto surface coating solution in a KitchenAid 5 - quart hood mixer. After mixing at low speed for 30 minutes, the mixture was dried in an oven at 60 - 70 °C for 4 hours. The resulting adsorbent was in powder form, not extruded, not acid - activated, and free of residual acid. Examples 16 - 18

[0101] For each of Examples 16 through 18, it was prepared using a double surface treatment with a quaternary amine surface coating solution and a mercapto surface coating solution. Tables 3A - 3B show the various loading levels utilized for the quaternary amine surface coating solution and for the mercapto surface coating solution to examine the effect of the PFAS affinity functional group on PFAS removal. As described above, the quaternary amine surface coating solution contains a quaternary amine compound and water (the quaternary amine compound is dispersed in DI water). In Examples 16 - 18, the quaternary amine surface coating solution for the surface coating of sepiolite was prepared by mixing Kemira Superfloc C - 577 (a mono - quaternary amine compound, a 1,2 - ethanediamine polymer) with DI water for 10 minutes in a 100 mL glass beaker on a magnetic stir plate (with (chloromethyl)oxirane and N - methylmethanamine). The sepiolite feedstock was then mixed with the quaternary amine surface coating solution at low speed in a KitchenAid 5 - quart hood mixer for about 30 minutes. In Examples 16 - 18, since the quaternary amine compound included (or was) a mono - quaternary amine compound, thus, the quaternary amine surface coating solutions of Examples 16 - 18 each contained a mono - quaternary amine compound and DI water. The weight of the mono - quaternary amine in the exemplary mono - quaternary compound (Kemira Superfloc C - 577) is estimated to be about 50% of the total weight of the Kemira Superfloc C - 577 solution used. Further, each of the quaternary amine surface coating solutions of Examples 16 - 18 did not contain di - quaternary amines (plural), and also did not contain oleylamine, and did not contain octylamine either.

[0102] As can be seen from Tables 3A - 3B, in Examples 16 - 18, various loading levels of surface coating agents and solvents were utilized for the mercapto surface coating solution. The mercapto surface coating solution contains a surface coating agent and a solvent. The surface coating agent contains one or more mercapto groups. In Examples 16 - 18, the surface coating agent contains silane and one or more mercapto groups, and such surface coating agents are referred to as "mercaptosilanes" in Tables 3A - 3B. In each of Examples 16 - 18, the surface coating agent utilized was gamma - mercaptopropyltrimethoxysilane (Momentive Silquest A - 189), and the solvent was ethanol.

[0103] In Examples 16 - 18, the mercapto surface coating solution for the surface coating of sepiolite was prepared by mixing the surface coating agent (mercaptosilane) with the solvent (ethanol) in a 100 mL glass beaker on a magnetic stirring plate for 10 minutes. Next, the sepiolite feedstock, which had been surface functionalized with a quaternary amine surface coating solution, was then mixed with the mercapto surface coating solution in a KitchenAid 5 - quart hood mixer. After mixing at low speed for 30 minutes, the mixture was dried in an oven at 60 - 70 °C for 4 hours. The resulting adsorbent was in powder form, not extruded, not acid - activated, and free of residual acid (acid - free).

[0104] Examples 3 - 18 were prepared with various amounts of loading levels of mercaptosilane and quaternary amine to examine the effect on PFAS removal. As shown in Table 5, the surface area measurements of products containing doubly surface - functionalized natural attapulgite (Examples 4 - 12) indicate that the surface coating reduces the surface area of the attapulgite used as the feedstock, and the surface area measurements of products containing doubly surface - functionalized natural sepiolite (Examples 13 - 18) indicate that the surface coating reduces the surface area of the sepiolite used as the feedstock.

Table 5

[0105] Figure 3 shows the pore size distributions (measured by mercury intrusion porosimetry) of the attapulgite feedstock and the surface-functionalized samples of Examples 4 and 7. Figure 3 shows that for the attapulgite feedstock and Examples 4 and 7, the peak positions of the small intrinsic pores were from about 10 nm to about 25 nm, and the peak positions of the large internal pores were from about 2.5 microns to about 11 microns. As used herein, "intrinsic pores" are pores that are (a) located on the surface of attapulgite particles or (b) located within the structure of attapulgite particles. As used herein, "internal pores" are pores that are located between attapulgite particles. Figure 13 shows the pore size distributions (measured by mercury intrusion porosimetry) of the sepiolite feedstock and the surface-functionalized samples of Examples 13 and 18. Figure 13 shows small intrinsic pores near 10 - 25 nm for Examples 13 and 18, with peak positions of about 14 nm (Example 13) and about 17 nm (Example 18) for the small intrinsic pores. Figure 13 also shows, for Example 13, large internal pores from 600 nm to 40 microns, with peak positions of about 2 microns (large peak), 5.7 microns (small peak), 12 microns (medium peak), and 29 microns (small peak) for the large internal pores. Figure 13 also shows, for Example 18, large internal pores from 600 nm to 22 microns, with peak positions of about 2.5 microns (large peak), 5.7 microns (small peak), and 16 microns (small peak) for the large internal pores. As shown in Table 4, surface functionalization slightly decreases the pore volume and porosity. Table 4 also shows that the particle size measured by a laser particle size analyzer can slightly increase after surface functionalization with mercaptosilane. The large surface area and unique interporous structure of the attapulgite feedstock contribute to its effectiveness as an adsorbent for various applications, including PFAS adsorption of the resulting product as it contains natural attapulgite. Similarly, the large surface area and unique pore structure of the sepiolite feedstock contribute to its effectiveness as an adsorbent for various applications, including PFAS adsorption of the resulting product as it contains natural sepiolite. PFAS Adsorption Test

[0106] The products disclosed herein can each be used to adsorb PFAS in liquids. For each of the feed materials and the PFAS adsorption tests for the adsorbents of Examples 1-3, a 20 parts per billion (ppb) PFAS standard solution containing 35 PFAS substances was spiked into DI water to bring the PFAS concentration to around 40 parts per trillion (ppt). For the PFAS adsorption tests of each adsorbent of Examples 4-18, a 20 ppb PFAS standard solution containing 35 PFAS substances was spiked into DI water to bring the PFAS concentration to around 80 ppt. The actual PFAS concentration was measured using liquid chromatography-mass spectrometry (LC-MS) according to the standard EPA method 533 (Determination of Per- and Polyfluoroalkyl Substances in Drinking Water by Isotope Dilution Anion Exchange Solid Phase Extraction and Liquid Chromatography / Tandem Mass Spectrometry).

[0107] For the PFAS adsorption test for each of Examples 1-18, 300 mg of each adsorbent (Examples 1-18) was mixed with 250 mL of the prepared PFAS solution on a shaker at room temperature for 18 hours. After the adsorption test, the adsorbent was separated from the liquid using the EPA standard solid phase extraction (SPE) method SW846 (Test Methods for Evaluating Solid Wastes, Physical / Chemical Methods). The PFAS concentration in the filtrate was measured using LC-MC based on EPA method 533.

[0108] The individual PFAS removal efficiencies were calculated as follows:

Equation

[0109] The total PFAS removal efficiency was calculated as follows: [Number]

[0110] The results of PFAS adsorption tests using a stock solution with a PFAS concentration of 40 ppt are shown in Tables 6 and 7. Figure 4 (or Table 8) shows that the sample treated with the mercapto surface coating solution of Example 1 has a significantly improved total PFAS removal efficiency compared to the untreated natural attapulgite feedstock and the sample treated with the quaternary amine surface coating solution (containing a mono - quaternary amine compound) of Example 2. Surface treatment (Example 3) with both the mercapto surface coating solution (such as mercaptosilane and ethanol) and the quaternary amine surface coating solution (containing a mono - quaternary amine compound and DI water) unexpectedly further increases the total amount of PFAS removed. This is thought to be due to the interaction of these two functional groups (the mercapto functional group and the mono - quaternary amine compound functional group) to enhance the PFAS affinity to the attapulgite surface.

[0111] Figure 5 shows the effect of surface functionalization treatment of the attapulgite feedstock with the mercapto surface coating solution of Example 1 (see Tables 3A, 3B and 6), the quaternary amine surface coating solution of Example 2 (see Tables 3A, 3B, 6), and the double surface functionalization treatment of the quaternary amine surface coating solution and the mercapto surface coating solution of Example 3 (see Tables 3A, 3B, 7) on the removal of selected PFAS substances in a 40 ppt synthetic PFAS starting solution. Similar to the removal of PFAS as a whole, treatment with both the mercapto surface coating solution (containing mercaptosilane and ethanol) and the quaternary amine surface coating solution (containing a mono - quaternary amine compound and DI water) of Example 3 enhances the removal of these selected PFAS substances compared to treatment with the mercapto surface coating solution alone (Example 1) and treatment with the quaternary amine surface coating solution alone (Example 2).

Table 6-1

Table 6-2

[0112]

Table 7-1

Table 7-2

Table 7-3

[0113] Table 8 shows a comparison of the total PFAS removal efficiency in 40 ppt PFAS solutions for Examples 1-3 prepared from the feedstock using untreated attapulgite feedstock and surface functionalization treatments. Similar to Tables 3A-3B, in Table 8, the weight percentage of the surface coating agent (example mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent, and the weight percentage of the quaternary amine is defined as a percentage of the weight of the resulting adsorbent. It is unexpected that the combination of quaternary amine and mercaptosilane surface coating on attapulgite enhances PFAS adsorption compared to quaternary amine alone or mercaptosilane surface coating on attapulgite.

Table 8

[0114] Tables 9 and 10 show the results of PFAS adsorption tests in prepared solutions with a PFAS concentration of 80 ppt, using samples (Examples 4 - 9) treated with both a mercapto surface coating solution (containing mercaptosilane and ethanol) and a quaternary amine surface coating solution (containing a quaternary amine compound and DI water). Figure 6 shows that the total removal efficiency of PFAS increases as the total loading level of mercaptosilane and quaternary amine increases. A similar trend is also observed for the selected PFAS substances (Figure 7).

[0115] Figure 8 shows, for Example 8, that among 35 PFAS substances (see Table 10), 80% or more removal was achieved for 20 PFAS substances, 85% or more removal was achieved for 18 PFAS substances, and 90% or more removal was achieved for 12 PFAS substances.

Table 9 - 1

Table 9 - 2

Table 9 - 3

[0116]

Table 10 - 1

Table 10 - 2

Table 10 - 3

[0117] Table 11 shows a comparison of the total PFAS removal efficiency in 80 ppt PFAS solutions for Examples 4 - 9 prepared from the feedstock using surface functionalization treatment. Similar to Tables 3B and 8, the weight percentage of the surface coating agent (e.g., mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent, and the percentage of the quaternary amine is defined as a percentage of the weight of the resulting adsorbent.

Table 11

[0118] Table 12 shows a comparison of the total PFAS removal efficiency in 80 ppt PFAS solutions for Examples 10 - 12 prepared from the feedstock using surface functionalization treatment. Figure 9 shows that the total PFAS removal efficiency increases as the total loading level of mercaptosilane and the quaternary amine increases. Similar to Tables 3B and 8, the weight percentage of the surface coating agent (e.g., mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent, and the percentage of the quaternary amine is defined as a percentage of the weight of the resulting adsorbent.

Table 12 - 1

Table 12 - 2

Table 12 - 3

Table 12 - 4

[0119] FIG. 10 is a graph showing the amounts of PFAS substances (out of a total of 35 PFAS substances in Table 12) for Example 11 with removal efficiencies of 90% or more, 95% or more, or 97% or more. FIG. 11 illustrates exemplary PFAS removal efficiencies of Example 11 for the most common PFAS substances (see Table 12). FIG. 11 shows that for 35 PFAS substances, removals exceeding 90% were achieved for the 35 PFAS substances tested by Example 11, removals exceeding 96% were achieved for PFOA by Example 11, removals exceeding 97% were achieved for PFOS by Example 11, removals exceeding 95% were achieved for PFHxS by the adsorbent of Example 11, and removals exceeding 98% were achieved for PFNA.

[0120] Table 13 shows a comparison of the total PFAS removal efficiencies in an 80 ppt PFAS solution for Examples 13 - 15 prepared from feed materials using surface functionalization treatments. The "ND" used here and in Table 13 means "not detectable" or "not detected". As can be seen from Table 13, for the effluent of Example 13, various PFAS were ND (not detected). The measured value of ND occurs when the effluent does not contain PFAS content or when such PFAS content in the effluent is very trace and below the amount detectable by the instrument (in other words, when such PFAS content is below the detection limit of the instrument). For example, in Table 13, PFOA was not detected in the effluent for Example 13. In Table 13, when PFAS was not detectable / not detected in the effluent, the removal efficiency (%) for such examples was in the range from over 99% to 100% depending on the detection limit for that PFAS (see Table 16 for PFAS detection limits).

Table 13 - 1

Table 13 - 2

Table 13 - 3

[0121] Table 14 shows a comparison of total PFAS removal efficiency in 80 ppt PFAS solution for Examples 16-18 prepared from feedstock using surface functionalization treatment. "ND" as used herein and in Table 14 means "not detectable" or "not detected". As can be seen from Table 14, various PFASs were ND (not detected) in the wastewater of various examples. As mentioned above, ND readings occur when the wastewater does not contain PFAS content or when it is very low such that such PFAS content is below the amount that can be detected by the instrument (when the content of such PFAS is below the detection limit of the instrument). For example, in Table 14, PFNA was not detected in the wastewater for Example 18. In Table 14, when PFAS was not detected in the wastewater for a certain example, the removal efficiency (%) of such example ranged from more than 99% to 100% depending on the detection limit for that PFAS (see Table 16 for PFAS detection limit). [Table 14-1] [Table 14-2] [Table 14-3]

[0122] Figure 14 is based on the data in Table 13. Figure 14 is a graph showing the amounts of PFAS substances (among the total 35 PFAS substances in Table 13) for Example 13 with removal efficiencies of 90% or more, 95% or more, or 97% or more. As explained above, when the selected PFAS for Example 13 was not detected in the wastewater, the removal efficiency (%) of Example 13 for that selected PFAS was in the range from 99% to 100% depending on the detection limit of that PFAS. Table 15 shows the removal efficiency of Example 13 for the most common PFAS substances. After separation in Example 13, PFOA, PFOS, PFHxS, and PFNA were not detected in the wastewater. More specifically, the instrument used to measure PFOA in the wastewater does not detect the PFOA content in the wastewater when the PFOA content is in the range from zero to less than 0.38 ppt. Thus, when the PFOA level is from zero ppt to 0.38 ppt, the removal efficiency exceeds 99.53%. Similarly, the instrument used to measure PFOS in the wastewater does not detect the PFOS content in the wastewater when the PFOS content is in the range from zero to less than 0.26 ppt. Thus, when the PFOS content is from zero ppt to less than 0.26 ppt, the removal efficiency exceeds 99.69%. The instrument used to measure PFHxS in the wastewater does not detect the PFHxS content in the wastewater when the PFHxS content is in the range from zero to less than 0.23 ppt. Thus, when the PFHxS content is from zero ppt to less than 0.23 ppt, the removal efficiency exceeds 99.69%. The instrument used to measure PFNA in the wastewater does not detect the PFNA content in the wastewater when the PFNA content is in the range from zero to less than 0.21 ppt. Thus, when the PFNA content is from zero ppt to less than 0.21 ppt, the removal efficiency exceeds 99.72%.

Table 15

[0123] Table 16 shows the detection limits for each of the various PFAS substances that were ND in Tables 13 - 14. The detection limit is the minimum amount of the selected PFAS that can be detected by the instrument used to measure the PFAS content. The instrument utilized to measure such PFAS substances in the wastewater does not detect such PFAS substances in the wastewater when the content is below the detection limit amount shown in Table 16. For example, when the PFOA content is less than 0.38 ppt from zero ppt, the PFOA content in the wastewater cannot be detected by the instrument used.

Table 16

[0124] Table 17 shows a comparison of the total PFAS removal efficiency in an 80 ppt PFAS solution for Examples 13 - 18 prepared from the feed materials using surface functionalization treatment. Similar to Table 3B, the weight percentage of the surface coating agent (example is mercaptosilane) is defined as a percentage of the weight of the resulting adsorbent, and the percentage of the quaternary amine is defined as a percentage of the weight of the resulting adsorbent.

Table 17

[0125] Disclosed herein is a method for adsorbing at least one PFAS from a liquid. The liquid includes, but is not limited to, water (e.g., fresh water, seawater, or other of that kind), edible oil, wastewater, treated water, or combinations thereof. For example, the liquid can include or be water - in - oil or oil - in - water. The method can include mixing / contacting the liquid with any one of the products disclosed herein that includes attapulgite and / or sepiolite surface - functionalized with a quaternary amine surface - coating solution and a mercapto surface - coating solution. The liquid and the product can form a slurry.

[0126] Mixing / contacting may be performed at a contact time and product loading sufficient to reduce the amount of PFAS in the liquid during the contact time, such that 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% PFAS efficiency (for removal of PFAS from the liquid) is achieved. For example, in an exemplary embodiment, the product may have a PFAS removal efficiency of 70% - 100% at a product loading of 0.5 - 2 g per liter of liquid and a contact time of about 12 - 25 hours in the liquid; in an improvement, the product may have a PFAS removal efficiency of 80% - 100% at a product loading of 0.5 - 2 g per liter of liquid and a contact time of about 12 - 25 hours in the liquid; in an improvement, the product may have a PFAS removal efficiency of 90% - 100% at a product loading of 0.5 - 2 g per liter of liquid and a contact time of about 12 - 25 hours in the liquid; in another improvement, the product may have a PFAS removal efficiency of 95% - 100% at a product loading of 0.5 - 2 g per liter of liquid and a contact time of about 12 - 25 hours in the liquid. Other loadings and contact times may also be utilized.

[0127] The quaternary amine surface coating solution may include water (e.g., DI water) and (a) a mono - quaternary amine compound containing one or more mono - quaternary amines attached to the attapulgite / sepiolite surface, or (b) a di - quaternary amine compound containing one or more di - quaternary amines attached to the attapulgite / sepiolite surface. When the quaternary amine surface coating solution includes one or more mono - quaternary amine compounds, the quaternary amine surface coating solution (and product) does not include di - quaternary amines. When the quaternary amine surface coating solution includes one or more di - quaternary amine compounds, the quaternary amine surface coating solution (and product) does not include mono - quaternary amines. The mercapto surface coating solution may include a solvent and one or more mercapto groups chemically bonded to the attapulgite or sepiolite surface.

[0128] The method may further include separating the product from the liquid to recover a liquid that results in having less PFAS than the liquid had prior to mixing. In one embodiment, the weight percentages of the components of the product may be as follows: 85 - 94 wt% attapulgite; 2.5 - 15 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 1 - 8 wt% of a surface coating agent containing one or more mercapto groups. The product may have a surface area in the range of 45 - 160 m 2 / g or 45 - 150 m 2 / g or 45 - 130 m 2 / g or 50 - 100 m 2 / g as measured using the BET method. In another embodiment, the weight percentages of the components of the product may be as follows: 76 - 97 wt% sepiolite; 1 - 16 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 0.5 - 8 wt% of a surface coating agent containing one or more mercapto groups. The product may have a surface area in the range of 76 - 276 m 2 / g or 86 - 254 m 2 / g or 91 - 243 m 2 / g or 96 - 231 m 2 / g as measured using the BET method. The resulting liquid can be recovered from the slurry by filtration or other suitable methods known to those skilled in the art. The products disclosed herein can be used in a filtration system as a body feed alone and / or as a precoat mixed with a filter aid (such as diatomaceous earth and perlite).

[0129] Other adsorption methods can also be utilized. Such other adsorption methods can include passing the PFAS-containing liquid through a column filled with the double surface-functionalized attapulgite / sepiolite disclosed herein. The contact time can be adjusted by varying process parameters such as, for example, the length of the column, the diameter of the column, the packing density of the adsorbent, and / or the flow rate of the liquid.

Industrial Applicability

[0130] Generally, the above disclosure finds utility in the removal of PFAS contained in liquids. Historically, common commercially available PFAS removal technologies include activated carbon adsorption, anion exchange resins, and high-pressure membranes. Activated carbon is a low-efficiency technology. Anion exchange resin and high-pressure membrane technologies are expensive due to high material and equipment costs.

[0131] The novel products disclosed herein can be used as adsorbents for reducing PFAS in liquids. Such products have high removal efficiency for PFAS, which significantly shortens the treatment time and provides even more removal of PFAS from the liquid. Further, compared to commercially utilized activated carbon, the products disclosed herein can be used in significantly smaller amounts, which creates even less waste to be disposed of. For example, the novel products can be used as body feed or pre-coat in a liquid filtration system for removing PFAS substances, with or without a filter aid. It can also be used to cover PFAS-contaminated sediments for PFAS soil remediation.

[0132] From the above, only specific embodiments have been described for illustrative purposes, but it will be recognized that alternatives and modifications will be apparent to those skilled in the art from the above description. These and other alternatives are equivalent and are considered to be within the spirit and scope of this disclosure and the appended claims.

Claims

1. A product for adsorbing at least one PFAS in a liquid, comprising: (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, the mono-quaternary amine compound containing one or more mono-quaternary amines attached to the attapulgite surface, and the di-quaternary amine compound containing one or more di-quaternary amines attached to the attapulgite surface; and (b) attapulgite surface-functionalized with a surface coating agent containing one or more mercapto groups chemically bonded to the attapulgite surface, When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain di-quaternary amines, When the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain mono-quaternary amines, The product is measured using the BET method and has a surface area in the range of 45 - 160 m 2 / g or 50 - 100 m 2 / g, and The product has a particle size distribution with a d of 6 - 30 microns (μm) or 10 - 25 microns or 12 - 25 microns or 12 - 23 microns 50 having The product.

2. The product according to claim 1, wherein the surface coating agent is mercaptosilane.

3. The product according to claim 1, wherein the product is in powder form and / or has not been extruded.

4. The product according to claim 1, which has a PFAS removal efficiency of 70-100%, 80-100%, 90-100%, 95-100% or 97-100% for at least one PFAS in the liquid at a product loading of 0.5-2 g of the product per liter of the liquid for 12-25 hours.

5. The product according to claim 1, which has a porosity of 40-90% and a pore volume of 0.7-1.5 mL / g.

6. The weight percentages of the components of the product are as follows: 85-94 wt% attapulgite; 2.5-15 wt% of the following: (i) mono-quaternary amine or (ii) di-quaternary amine; and 1-8 wt% surface coating agent The product according to claim 1.

7. The product according to claim 1, which does not contain oleylamine and octylamine.

8. The product according to claim 1, which does not contain residual acid.

9. A method for manufacturing a product for adsorbing at least one PFAS from a liquid, comprising: Selecting attapulgite as a feedstock, wherein the attapulgite selected as a feedstock prior to surface treatment contains 7-16 wt% or 9-14 wt% moisture as measured at a temperature of 104 °C; Surface-treating attapulgite with a quaternary amine surface coating solution, wherein the quaternary amine surface coating solution: (i) contains a mono-quaternary amine compound which contains one or more mono-quaternary amines that adhere to the surface of attapulgite, or (ii) contains a di-quaternary amine compound which contains one or more di-quaternary amines that adhere to the surface of attapulgite; and Surface-treating attapulgite with a mercapto surface coating solution, wherein the mercapto surface coating solution contains a surface coating agent which contains one or more mercapto groups that chemically bond to the surface of attapulgite comprises The resulting product has a surface area in the range of 45 - 160 m 2 / g as measured by the BET method, and When the quaternary amine surface coating solution contains a mono-quaternary amine compound, the product does not contain a di-quaternary amine, When the quaternary amine surface coating solution contains a di-quaternary amine compound, the product does not contain a mono-quaternary amine method.

10. The weight percentages of the components of the product are as follows: 85 - 94 wt% attapulgite; 2.5 - 15 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 1 - 8 wt% of a surface coating agent containing one or more mercapto groups comprises The product does not contain oleylamine and octylamine The method of Claim 9.

11. The quaternary amine surface coating solution further contains water, The mercapto surface coating solution further contains a solvent, The surface coating agent contains mercaptosilane The method of Claim 9.

12. The surface treatment of attapulgite with the mercapto surface coating solution follows the surface treatment of attapulgite with the quaternary amine surface coating solution, the method of Claim 9.

13. The quaternary amine surface coating solution further contains water, the method of Claim 12.

14. The following: Drying attapulgite is further included, and one or more mono-quaternary amines are dried on the attapulgite of the produced product, or one or more di-quaternary amines are dried on the attapulgite of the produced product, and the mercapto surface coating solution is dried on the attapulgite of the produced product, The produced product is in powder form or is not extruded The method of Claim 9.

15. The product has a particle size distribution having a d of 6 - 30 microns or 10 - 25 microns or 12 - 25 microns or 12 - 23 microns 50 The method of claim 9, having a particle size distribution having a d of

16. The product is the method of claim 9 having a PFAS removal efficiency of 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% for at least one PFAS in the liquid at a product loading of 0.5 - 2 g per liter of liquid over 12 - 25 hours.

17. A method for adsorbing at least one PFAS in a liquid, comprising: (a) a quaternary amine surface coating solution comprising a mono - quaternary amine compound or a di - quaternary amine compound, wherein the mono - quaternary amine compound comprises one or more mono - quaternary amines attached to the attapulgite surface and the di - quaternary amine compound comprises one or more di - quaternary amines attached to the attapulgite surface, and (b) contacting a product comprising attapulgite surface - functionalized with a surface coating agent containing one or more mercapto groups chemically bonded to the attapulgite surface with the liquid; and separating the product from the liquid to recover a liquid resulting in having a lower amount of PFAS than the liquid had prior to mixing comprising, the weight percentages of the components of the product are as follows: 85 - 94 wt% attapulgite, 2.5 - 15 wt% of (i) one or more mono - quaternary amines or (ii) one or more di - quaternary amines, and 1 - 8 wt% of a surface coating agent containing one or more mercapto groups, when the quaternary amine surface coating solution comprises one or more mono - quaternary amine compounds, the product does not contain a di - quaternary amine compound, when the quaternary amine surface coating solution comprises one or more di - quaternary amine compounds, the product does not contain a mono - quaternary amine compound, The product has a surface area in the range of 45 - 160 m 2 / g as measured using the BET method, and the removal efficiency of the product for PFAS is 10 - 100% at a product loading of 0.5 - 2 g per liter of liquid method.

18. The method of claim 17, wherein the liquid comprises water, cooking oil, wastewater, treated water or a combination thereof.

19. The method of claim 17, wherein the surface coating agent comprises mercaptosilane.

20. wherein the contact is for 12 - 25 hours and the PFAS removal efficiency of the product for at least one PFAS at a product loading of 0.5 - 2 g per liter of liquid is 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100%, the method of claim 17.

21. A product for adsorbing at least one PFAS in a liquid, comprising the following: (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, wherein the mono-quaternary amine compound contains one or more mono-quaternary amines attached to the surface of sepiolite, and the di-quaternary amine compound contains one or more di-quaternary amines attached to the surface of sepiolite; and (b) sepiolite surface-functionalized with a surface coating agent containing one or more mercapto groups chemically bonded to the sepiolite surface, When the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain di-quaternary amines, When the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain mono-quaternary amines, The product or surface-functionalized sepiolite has a surface area in the range of 76 - 276 m 2 / g or 80 - 254 m 2 / g as measured using the BET method, and The product or surface-functionalized sepiolite has a particle size distribution with a d of 10 - 25 microns or 11 - 22 microns or 12 - 21 microns 50 having The product.

22. The product according to claim 21, wherein the surface coating agent is mercaptosilane.

23. The product according to claim 21, wherein the product is in powder form and / or has not been extruded.

24. The product according to claim 21, which has a PFAS removal efficiency of 70 - 100%, 80 - 100%, 90 - 100%, 95 - 100% or 97 - 100% for at least one PFAS in the liquid at a product loading of 0.5 - 2 g of the product per liter of the liquid over 12 - 25 hours.

25. The product according to claim 21, which has a porosity of 62 - 86% and a pore volume of 1.3 - 3 mL / g.

26. The weight percentages of the components of the product are as follows: 76 - 97 wt% sepiolite; 1 - 16 wt% of the following: (i) mono-quaternary amine or (ii) di-quaternary amine; and 0.5 - 8 wt% surface coating agent The product according to claim 21, comprising.

27. The product according to claim 21, which does not contain oleylamine and octylamine.

28. The product according to claim 21, which does not contain residual acid.

29. A method for manufacturing a product for adsorbing at least one PFAS from a liquid, comprising the following: Selecting sepiolite as the feedstock, wherein the sepiolite selected as the feedstock prior to surface treatment contains 16 - 20 wt% moisture as measured by loss on ignition (LOI); Surface-treating sepiolite with a quaternary amine surface coating solution, wherein the quaternary amine surface coating solution is (i) a mono-quaternary amine compound containing one or more mono-quaternary amines adhering to the surface of sepiolite, or (ii) a di-quaternary amine compound containing one or more di-quaternary amines adhering to the surface of sepiolite; and Surface-treating sepiolite with a mercapto surface coating solution, wherein the mercapto surface coating solution contains a surface coating agent containing one or more mercapto groups chemically bonded to the surface of sepiolite comprising The resulting product has a surface area in the range of 76 - 276 m 2 / g as measured using the BET method, and when the quaternary amine surface coating solution contains a mono-quaternary amine compound, the product does not contain a di-quaternary amine, when the quaternary amine surface coating solution contains a di-quaternary amine compound, the product does not contain a mono-quaternary amine method.

30. The weight percentages of the components of the product are as follows: 76 - 97 wt% sepiolite; 1 - 16 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines; and 0.5 - 8 wt% of a surface coating agent containing one or more mercapto groups are included, the product does not contain oleylamine and octylamine The method of claim 29.

31. The quaternary amine surface coating solution further contains water, the mercapto surface coating solution further contains a solvent, the surface coating agent contains mercaptosilane The method of claim 29.

32. The surface treatment of sepiolite with the mercapto surface coating solution follows the surface treatment of sepiolite with the quaternary amine surface coating solution, the method of claim 29.

33. The quaternary amine surface coating solution further contains water, the method of claim 32.

34. The following: Drying sepiolite is further included, one or more mono-quaternary amines are dried on the sepiolite of the produced product, or one or more di-quaternary amines are dried on the sepiolite of the produced product, and the mercapto surface coating solution is dried on the sepiolite of the produced product, the produced product is in powder form or has not been extruded The method of claim 29.

35. The product has a particle size distribution having a d of 10-25 microns or 11-22 microns or 12-21 microns 50 The method of claim 29, having a particle size distribution having a d of 10-25 microns or 11-22 microns or 12-21 microns

36. The product is the method of claim 29, having a PFAS removal efficiency of 70-100%, 80-100%, 90-100%, 95-100% or 97-100% for at least one PFAS in the liquid at a product loading of 0.5-2 g per liter of the liquid for 12-25 hours.

37. A method for adsorbing at least one PFAS in a liquid, comprising the following: (a) a quaternary amine surface coating solution containing a mono-quaternary amine compound or a di-quaternary amine compound, the mono-quaternary amine compound containing one or more mono-quaternary amines attached to the sepiolite surface, and the di-quaternary amine compound containing one or more di-quaternary amines attached to the sepiolite surface; and (b) contacting a product containing sepiolite surface-functionalized with a surface coating agent containing one or more mercapto groups chemically bonded to the sepiolite surface with the liquid; and separating the product from the liquid to recover a liquid resulting from having a lower amount of PFAS than the liquid had prior to mixing comprising, the weight percentages of the components of the product are as follows: 76-97 wt% sepiolite, 1-16 wt% of (i) one or more mono-quaternary amines or (ii) one or more di-quaternary amines, and 0.5-8 wt% of a surface coating agent containing one or more mercapto groups, when the quaternary amine surface coating solution contains one or more mono-quaternary amine compounds, the product does not contain a di-quaternary amine compound, when the quaternary amine surface coating solution contains one or more di-quaternary amine compounds, the product does not contain a mono-quaternary amine compound, The product has a surface area in the range of 76 - 276 m 2 / g as measured using the BET method, the removal efficiency of the product for PFAS is 10-100% at a product loading of 0.5-2 g per liter of the liquid method.

38. The method of claim 37, wherein the liquid contains water, edible oil, wastewater, treated water, or a combination thereof.

39. The method of claim 37, wherein the surface coating agent contains mercaptosilane.

40. wherein the contact is for 12-25 hours, and the PFAS removal efficiency of the product for at least one PFAS at a product loading of 0.5-2 g per liter of the liquid is 70-100%, 80-100%, 90-100%, 95-100 or 97-100%, the method of claim 37.

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