Processing carbon for pollutant removal.

Abstract

The present invention relates to a method for treating carbon to improve its ability to capture and retain pollutants, and to treated carbon produced by such a method. The treatment of carbon includes treating the carbon with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ The method includes contacting the compound with one or more cations selected from the group consisting of:

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 290,074, filed December 16, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to methods of treating carbon to improve its ability to capture and retain pollutants, and to treated carbon produced by such methods. [Background technology]

[0003] This section provides background information related to the present disclosure and is not necessarily prior art.

[0004] Water purification technology is of fundamental importance with regard to daily life. To use water for drinking or other purposes, it must be purified to an acceptable level by removing contaminants. Per- and polyfluoroalkyl substances (PFAS) are of particular concern and are particularly important to remove from water. Existing technologies for water purification by removing contaminants, including PFAS, have problems with efficiency and environmental sustainability. For example, technologies that capture contaminants such as PFAS with ion exchange resins or carbon beds currently require replacement of the beds and disposal of used beds in landfills. Air purification is another important technology that removes harmful contaminants from the air to improve our health and protect the environment. There is also a need for purification technologies for other liquids and gases.

[0005] Thus, although technologies already exist for the removal of pollutants, such as water purification and air purification, there remains a need for improved technologies that provide more effective removal of pollutants. Summary of the Invention [Means for solving the problem]

[0006] In one aspect, disclosed herein is a method for treating carbon to improve its pollutant removal capacity. The method includes treating carbon with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ The method includes contacting the compound with one or more cations selected from the group consisting of:

[0007] In some embodiments, (a) hydroxide and / or peroxide and (b) one or more cations are provided in a single aqueous liquid or in two or more separate aqueous liquids for contacting the carbon. In some embodiments, the (a) hydroxide and / or peroxide comprises sodium hydroxide. In some embodiments, the (a) hydroxide and / or peroxide comprises hydrogen peroxide. Also, in some embodiments, the (a) hydroxide and / or peroxide comprises sodium peroxide.

[0008] In some embodiments, (b) the one or more cations are Ca 2+ For example, Ca 2+ may be provided as calcium hydroxide.

[0009] In some embodiments, (b) the one or more cations are Al 3+ For example, Al 3+ may be provided as aluminum sulfate, aluminum hydroxide, or sodium aluminate.

[0010] In some embodiments, (a) hydroxide and / or peroxide are provided in a first aqueous liquid and (b) one or more cations are provided in a second aqueous liquid. In some embodiments, the first aqueous liquid is contacted with one or more ionic contaminants prior to the second aqueous liquid. In other embodiments, the method includes contacting carbon with (a) sodium hydroxide and / or hydrogen peroxide, and (b) calcium hydroxide, aluminum hydroxide, and / or aluminum sulfate.

[0011] In some embodiments, the method further comprises rinsing the carbon with an acidic aqueous solution. In some embodiments, the acidic aqueous solution comprises hydrochloric acid, citric acid, sulfuric acid, nitric acid, or any combination thereof. For example, the acidic aqueous solution may comprise hydrochloric acid. In other embodiments, the acidic aqueous solution comprises an acid salt. For example, the acidic aqueous solution may comprise FeCl2, FeCl3, or a combination thereof. Also, in some embodiments, the acid rinse occurs after the carbon has been contacted with (a) hydroxides and / or peroxides, and (b) one or more cations.

[0012] In some embodiments, the method further includes rinsing the carbon with water, in some embodiments, the water is substantially free of additives, and in some embodiments, the water rinse occurs after the carbon has been contacted with (a) hydroxide and / or peroxide, and (b) one or more cations, and optionally after the acid rinse.

[0013] In some embodiments, the method further comprises contacting the carbon with a surfactant. In some embodiments, the surfactant is selected from a fatty acid, a sulfone, a phosphate, a polyether, a sulfate, a polyol, or any combination thereof. For example, the surfactant may be selected from a fatty acid, a sulfone, or a phosphate. In some embodiments, the surfactant is selected from sodium dodecyl sulfate (SDS), sorbitan monolaurate, polyethylene glycol (PEG), or any combination thereof. In some embodiments, (a) the surfactant is contacted with the carbon before the hydroxide and / or peroxide is contacted with the carbon. Also, in some embodiments, (a) the surfactant is contacted with the carbon after the hydroxide and / or peroxide is contacted with the carbon.

[0014] In some embodiments, the method further comprises contacting the carbon with an antifreeze agent. For example, the antifreeze agent may be selected from the group consisting of propylene glycol, polypropylene glycol, polyethylene glycol, glycerol, polyvinyl alcohol, carboxymethyl cellulose, ribose, sucrose, glucose, rhamnose, xylose, fructose, raffinose, stachyose, low molecular weight hydroxyethyl starch, maltodextrin, cellodextrin, and combinations thereof. In some embodiments, the antifreeze agent comprises glycerol. In some embodiments, (a) the antifreeze agent contacts the carbon before the hydroxide and / or peroxide contacts the carbon. Also, in some embodiments, (a) the antifreeze agent contacts the carbon after the hydroxide and / or peroxide contacts the carbon.

[0015] In some embodiments, the carbon is activated carbon. In some embodiments, the activated carbon is granular activated carbon. In some embodiments, the carbon comprises a powder, granules, beads, pellets, fabric, felt, non-woven fabric, or composite comprising a material selected from carbon, nitrogen-doped carbon, silicon-doped carbon, boron-doped carbon, charcoal, graphite, biochar, coke, carbon black, or any combination thereof. For example, the carbon comprises activated charcoal powder, granules, pellets, beads, or any combination thereof. Also, in some embodiments, the carbon comprises sintered carbon.

[0016] In some embodiments, carbon is treated with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ and then drying.

[0017] In another aspect, disclosed herein is a treated carbon. The treated carbon is a carbon-containing solution that is prepared by treating carbon with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ with one or more cations selected from the group consisting of:

[0018] Other features and advantages of the invention will become apparent from the following detailed description, the drawings, and the claims.

[0019] The following figures are provided as examples and are not intended to limit the scope of the claimed invention. [Brief description of the drawings]

[0020] [Figure 1] 1 is a plot showing PFOA concentration in effluent for treated and untreated GAC according to Example 1.

[0021] [Diagram 2] 1 is a chart showing adsorption isotherms. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] I. Definition

[0023] The terms used herein are for the purpose of describing particular example configurations only and are not intended to be limiting. As used herein, the singular articles "a," "an," and "the" may be intended to include the plural unless the context clearly dictates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring their execution in the particular order described or illustrated, unless specifically identified as an order of execution. Additional or alternative steps may be employed.

[0024] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as "first", "second", and other numerical terms do not imply an arrangement or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section described below may be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary configuration.

[0025] The terms before and after refer to a process step or other event that occurs before or after in time but allows for intermediate process steps or events to occur between them. Immediately before or immediately after refers to a process step or other event that occurs before or after in time without an intermediate process step or event occurring. In some embodiments, steps described herein as before or after occur immediately before or after the step or steps they refer to. In other embodiments, intermediate steps occur.

[0026] Terms such as above, below, top, bottom, right, left, etc. may be used herein to describe the location of various elements relative to other elements. These terms represent the location of elements in an exemplary configuration. However, as would be apparent to one of ordinary skill in the art, elements can be spatially rotated without departing from the present disclosure, and therefore these terms should not be used to limit the scope of the present disclosure.

[0027] As used herein, when an element is "adjacent," "engaged," "connected," "attached," or "coupled" to another element, it may be directly adjacent, engaged, connected, attached, or coupled to the other element, or there may be intervening elements. In contrast, when an element is "directly adjacent," "directly engaged," "directly connected," "directly attached," or "directly coupled" to another element, there may be no intervening elements or layers. Other words used to describe relationships between elements should be interpreted similarly (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0028] As used herein, the term "activated carbon" refers to a form of carbon that has been processed to have small pores that increase its available surface area.

[0029] As used herein, "polyfluoroalkyl ion" refers to an ionic compound containing an alkyl chain that has multiple fluoro substitutions and is optionally further substituted with ethers, alcohols, amines (including substituted amines), carboxylic acid groups, and the like.

[0030] "Perfluoroalkyl and polyfluoroalkyl substances" or "PFAS" includes, but is not limited to, the following substances: perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid, perfluorononanesulfonic acid, perfluorodecanesulfonic acid, perfluorododecanesulfonic acid, perfluorooctanesulfonamide, and N-methylperfluoro-1-octanesulfonamide. perfluorohexanesulfonic acid (4:2), 1H,1H,2H,2H-perfluorooctanesulfonic acid (6:2), 1H,1H,2H,2H-perfluorodecanesulfonic acid (8:2), 1H,1H,2H,2H-perfluorododecanesulfonic acid (10:2), N-methylperfluorooctanesulfonamideacetic acid, N-ethylperfluorooctanesulfonamide Amidoacetic acid, 2-(N-methylperfluoro-1-octanesulfonamido)-ethanol, 2-(N-ethylperfluoro-1-octanesulfonamido)-ethanol, tetrafluoro-2-(heptafluoropropoxy)propanoic acid ("GenX"), 4,8-dioxa-3H-perfluorononanoic acid, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, or 9-chlorohexadecafluoro-2-oxanone-1-sulfonic acid. PFAS also include partially fluorinated acids. The conjugate bases of these acids are examples of polyfluoroalkyl ions. Trapping PFAS includes trapping the conjugate bases of the PFAS.

[0031] "PFOS" refers to perfluorooctanesulfonic acid. Capture / release of PFOS includes capture / release of its conjugate base, perfluorooctanesulfonate.

[0032] "PFOA" refers to perfluorooctanoic acid. Capture / release of PFOA includes capture / release of its conjugate base, perfluorooctanoate.

[0033] II. Methods of Treating Carbon

[0034] In one aspect, provided herein is a method for treating carbon to improve its pollutant removal capacity. The method comprises treating carbon with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ The method includes contacting the compound with one or more cations selected from the group consisting of:

[0035] In some embodiments, (a) hydroxide and / or peroxide and (b) one or more cations are provided in a single aqueous liquid or two or more separate aqueous liquids for contacting the carbon. For example, the carbon can be placed in a vessel such as a column, and the aqueous liquid(s) can be passed through the vessel to contact the carbon with (a) hydroxide and / or peroxide and (b) one or more cations present in the liquid(s). The carbon can be a carbon bed and can have any shape.

[0036] In some embodiments, the (a) hydroxide and / or peroxide comprises sodium hydroxide. In some embodiments, the (a) hydroxide and / or peroxide comprises hydrogen peroxide. In some embodiments, the (a) hydroxide and / or peroxide comprises sodium peroxide.

[0037] In some embodiments, (b) the one or more cations are Ca 2+In some embodiments, Ca 2+ is provided as calcium hydroxide. In some embodiments, Ca 2+ is provided as calcium chloride. In some embodiments, (b) the one or more cations are Al 3+ In some embodiments, Al 3+ is provided as aluminum sulfate. In some embodiments, Al 3+ is provided as sodium aluminate. In some embodiments, Al 3+ is provided as aluminum hydroxide. In some embodiments, aluminum hydroxide is used in conjunction with sodium hydroxide.

[0038] In some embodiments, (a) the hydroxide and / or peroxide are provided in a first aqueous liquid and (b) the one or more cations are provided in a second aqueous liquid. In some embodiments, the first aqueous liquid is contacted with one or more ionic contaminants prior to the second aqueous liquid. In other embodiments, the second aqueous liquid is contacted with one or more ionic contaminants prior to the first aqueous liquid.

[0039] In some embodiments, the second aqueous liquid further comprises an antifreeze agent and a surfactant. The antifreeze agent and surfactant may be any antifreeze agent and surfactant described herein. In some embodiments, (a) hydroxide and / or peroxide, and (b) one or more cations are provided in a single aqueous liquid.

[0040] Certain methods according to the invention include contacting carbon with (a) sodium hydroxide and / or hydrogen peroxide, and (b) calcium hydroxide, aluminum hydroxide, and / or aluminum sulfate.

[0041] Without wishing to be bound by theory, it is believed that, among other possible advantages, (a) the hydroxides and / or peroxides facilitate the breakdown of biofilms on the carbon, which allows for efficient removal of ionic contaminants from the carbon.

[0042] In some embodiments, the method of treating the carbon further comprises rinsing the carbon with an acidic aqueous solution. In some embodiments, the acidic aqueous solution comprises hydrochloric acid, citric acid, sulfuric acid, nitric acid, or any combination thereof. For example, the acidic aqueous solution may comprise hydrochloric acid. In some embodiments, the acidic aqueous solution comprises an acid salt. For example, the acidic aqueous solution may comprise FeCl2, FeCl3, or a combination thereof. In some embodiments, the acid rinse occurs after the carbon has been contacted with (a) hydroxides and / or peroxides, and (b) one or more cations.

[0043] In some embodiments, the method of treating carbon further comprises rinsing the carbon with water. In some embodiments, the water is substantially free of additives. In some embodiments, the water rinse occurs after the carbon has been contacted with (a) hydroxide and / or peroxide, and (b) one or more cations, and optionally after an acid rinse.

[0044] In some embodiments, the method of treating the carbon further comprises contacting the carbon with a surfactant. The surfactant can be an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or any combination thereof. In some embodiments, the surfactant is selected from a fatty acid, a sulfone, or a phosphate. In some embodiments, the surfactant is selected from a fatty acid, a sulfone, a phosphate, a polyether, a sulfate, a polyol, or any combination thereof. For example, the surfactant can comprise a fatty acid. In some embodiments, the surfactant comprises a sulfone. In other embodiments, the surfactant comprises a phosphate. In some embodiments, the surfactant comprises a polyether. In some embodiments, the surfactant comprises a sulfate (e.g., sodium dodecyl sulfate (SDS)). In some embodiments, the surfactant comprises a polyol.

[0045] Suitable polyethers include, by way of non-limiting example, polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), or any combination thereof. In some embodiments, the polyether comprises PEG. The PEG may have an average molecular weight of less than about 1,000 g / mol, less than about 750 g / mol, less than about 600 g / mol, or less than about 550 g / mol. In some embodiments, the PEG is PEG500, PEG400, PEG300, or any combination thereof. For example, the PEG may be PEG300.

[0046] In some embodiments, the surfactant is selected from sodium dodecyl sulfate (SDS), sorbitan monolaurate, PEG, or any combination thereof.

[0047] In some embodiments, (a) the carbon is contacted with a surfactant before the hydroxide and / or peroxide is contacted with the carbon, in some embodiments, (a) the carbon is contacted with a surfactant after the hydroxide and / or peroxide is contacted with the carbon, and in some embodiments, the carbon is contacted with a surfactant simultaneously with the hydroxide and / or peroxide.

[0048] In some embodiments, the carbon is contacted with a surfactant before (a) the hydroxide and / or peroxide, and / or (b) one or more cations are contacted with the carbon. In other embodiments, the carbon is contacted with a surfactant after (a) the hydroxide and / or peroxide, and / or (b) one or more cations are contacted with the carbon. Also, in some embodiments, the carbon is contacted with a surfactant simultaneously with (a) the hydroxide and / or peroxide, and / or (b) one or more cations (e.g., a single aqueous liquid or two or more aqueous liquids include a surfactant).

[0049] In some embodiments, the method of treating carbon further comprises contacting the carbon with an antifreeze agent. In some embodiments, the antifreeze agent is selected from the group consisting of propylene glycol, polypropylene glycol, polyethylene glycol, glycerol, polyvinyl alcohol, carboxymethyl cellulose, ribose, sucrose, glucose, rhamnose, xylose, fructose, raffinose, stachyose, low molecular weight hydroxyethyl starch, maltodextrin, cellodextrin, and combinations thereof. For example, the antifreeze agent can include glycerol.

[0050] In some embodiments, (a) the carbon is contacted with the antifreeze agent before the hydroxide and / or peroxide is contacted with the carbon, in some embodiments, (a) the carbon is contacted with the antifreeze agent after the hydroxide and / or peroxide is contacted with the carbon, and in some embodiments, the carbon is contacted with the antifreeze agent simultaneously with the hydroxide and / or peroxide.

[0051] In some embodiments, the carbon is contacted with the antifreeze agent before the (a) hydroxide and / or peroxide, and / or (b) one or more cations are contacted with the carbon. In other embodiments, the carbon is contacted with the antifreeze agent after the (a) hydroxide and / or peroxide, and / or (b) one or more cations are contacted with the carbon. Also, in some embodiments, the carbon is contacted with the antifreeze agent simultaneously with the (a) hydroxide and / or peroxide, and / or (b) one or more cations (e.g., a single aqueous liquid or two or more aqueous liquids contain antifreeze agents).

[0052] In some embodiments, carbon is treated with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+ and then drying.

[0053] The carbon treated according to the present method can be any carbon material having any shape and size. The carbon treated according to the present invention is advantageously a carbon suitable for capturing pollutants, such as in water or air purification applications. A specific description of the carbon is provided in more detail below.

[0054] III. Treated Carbon

[0055] In one aspect, provided herein is a treated carbon. The carbon is treated with (a) hydroxides and / or peroxides, and (b) Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , and Fe 3+The carbon is treated by a method comprising contacting the carbon with one or more cations selected from the group consisting of:

[0056] The treated carbon can be any carbon material having any shape and size. In some embodiments, the carbon is activated carbon. A variety of carbon and activated carbon materials are commercially available, and methods of activating carbon are known in the art, such as by physical activation (carbonization and activation / oxidation) or chemical activation.

[0057] In some embodiments, the activated carbon is granular activated carbon (GAC). The GAC can be of mesh sizes such as 60×80, 8×20, 20×40, 8×30, 4×6, 4×8, or 4×10.

[0058] In some embodiments, the carbon comprises a powder, granules, beads, pellets, fabric, felt, non-woven fabric, or composite comprising a material selected from carbon, nitrogen-doped carbon, silicon-doped carbon, boron-doped carbon, charcoal, graphite, biochar, coke, carbon black, or any combination thereof. In some embodiments, the carbon comprises activated charcoal powder, granules, pellets, beads, or any combination thereof. In some embodiments, the carbon comprises sintered carbon. In some embodiments, the carbon is FILTRASORB® activated carbon bed by Calgon Carbon. In some embodiments, the carbon comprises BLACK PEARLS® 2000 (activated graphite) by Cabot corporation. In some embodiments, the carbon comprises PBX51 (activated graphite) by Cabot corporation. In some embodiments, the carbon comprises F400 granular activated carbon by Calgon Carbon.

[0059] In some embodiments, the carbon is porous. In some embodiments, the carbon has a porosity of about 30% to about 95%. In some embodiments, the carbon is an activated carbon metal oxide composite. In some embodiments, the carbon is activated graphite. In some embodiments, the carbon is activated charcoal. In some embodiments, the carbon is activated coal. In some embodiments, the carbon is activated coke. In some embodiments, the carbon is about 100 m 2 / g~about 2000m 2 In some embodiments, the carbon comprises an activated carbon having an average surface area of ​​about 2000 m / g. 2 / g~about 5000m 2 The activated carbon has an average surface area of ​​about 0.01 S / cm to about 100 S / cm.

[0060] In some embodiments, the carbon bed further comprises a binder dispersed therein. In some embodiments, the binder comprises a wax, a starch, a sugar, a polysaccharide, or any combination thereof. In some embodiments, the wax is a polyethylene wax. In some embodiments, the wax is a carnauba wax.

[0061] IV. Use of Treated Carbon

[0062] The treated carbon of the present invention is useful for capturing pollutants. For example, the treated carbon can be used to capture pollutants from water or air sources, i.e., in water purification or air purification applications. Other purification applications may also be suitable for the treated carbon.

[0063] Applications of the treated carbon of the present invention include removing pollutants (or pollutants) from air or water streams in both on-site and industrial processes such as spill cleanup, ground water remediation, drinking water filtration, air purification, and capture of VOCs from painting, dry cleaning, gasoline distribution, and other processes.

[0064] The treated carbon described herein is particularly useful for capturing perfluoroalkyl and polyfluoroalkyl substances (PFAS). For example, it is particularly useful for capturing PFAS from contaminated water sources. The inventors have observed that polyfluorinated compounds possess extremely hydrophobic moieties and therefore are not believed to adsorb to activated carbon by a conventional isothermal mechanism. They are believed to follow a nucleation, growth, and aggregation mechanism in which hydrophobic moieties aggregate together. These domains appear as micelles attached to the surface of activated carbon at high solution concentrations. To form, a few molecules of the perfluorocompound first find an adsorption site on the activated carbon with some initial affinity. Subsequent perfluorocompounds then preferentially adsorb to the previously adsorbed perfluorocompound. As the hydrophobic domains grow, the available surface area for adsorption increases until the micelles are too large to remain attached to the carbon surface. This adsorption mechanism results in an adsorbed amount vs. solution concentration curve that looks like a traditional Langmuir or Freundlich adsorption isotherm, but is different enough to be evident when fitting experimental data (Figure 2). The nucleation and growth model fits the experimental data better and predicts the behavior of macroscopic columns better. This description of the adsorption mechanism is useful for predicting the exhaustion behavior of activated carbon beds or columns when treating natural water sources. There is confusion in the literature regarding these compounds because most researchers perform brute force fitting to isotherms / surface coverage mechanisms obtained over a small concentration range. However, the nucleation and growth model fits and predicts the behavior better over many orders of magnitude of concentration.

[0065] Without being bound by theory, it is believed that the addition of divalent and trivalent metal salts to PFAS solutions causes the stabilization of these micelles. This is because most perfluorinated compounds found in water also contain hydrophilic moieties that usually form insoluble salts with the perfluorinated compounds. The effect of these insoluble salts is to increase the effective hydrophobicity of the perfluorinated compounds and stabilize both free and surface micelle formation. The size of these stabilized micelles can reach tens of microns. These insoluble salts can also be generated by non-fluorinated compounds. These insoluble hydrophobic salts can also be used to stabilize the micelles of perfluorinated compounds. Once these micelles form on the carbon, other organic compounds can become adsorbed into these micellar domains. These insoluble salts of perfluorinated compounds, fatty acids, sulfonic acids, or phosphoric acids are useful for pretreating the carbon surface to provide stabilization of nucleation and micelle formation on the carbon surface. They may be applied to the micelles of the metal salts and the precipitated compounds together with the carbon, or they may be applied sequentially to the carbon. It does not matter whether the metal salt is applied first and then the compound, or the compound is applied first and then the metal salt. Pretreatment of the carbon in this manner can increase the adsorption capacity of the carbon by up to 70-fold (e.g., 2-10-fold) for perfluorinated compounds found in natural or industrial water sources. This pretreatment may also improve the adsorption kinetics, which may reduce treatment times.

[0066] The treatment of the carbon according to the invention may occur prior to the process / application and may therefore be referred to as "pretreatment". Pretreatment may be followed by a process to capture contaminants on the carbon, followed by a regeneration process to remove and sequester the contaminants captured on the carbon so that the carbon can be used again to capture contaminants. Pretreatment according to the invention may improve the contaminant capture capacity, contaminant retention capacity, and / or regeneration capacity of the carbon.

[0067] In some embodiments, the pretreated carbon is useful for removing ionic contaminants from aqueous liquids, for example, water purification. Examples of ionic contaminants include those with organic ends bearing ionic moieties. Specific examples of ionic contaminants include polyfluoroalkyl ions, borates, phosphates, polyphosphates, sulfates, organic acids, fatty acids, humic substances, short chain PFAS, water soluble pharmaceuticals, detergents, water soluble insecticides, water soluble fungicides, water soluble bactericides, and any combination thereof. Another example of an ionic contaminant is a polyfluoroalkyl ion, such as perfluorooctane sulfonate or perfluorooctanoate. Perfluorooctane sulfonate is the conjugate base of perfluorooctane sulfonic acid (PFOS). Perfluorooctanoate is the conjugate base of perfluorooctanoic acid (PFOA). Other polyfluoroalkyl ions are perfluorobutane sulfonate and perfluorobutanoate. Perfluorobutanesulfonate is the conjugate base of perfluorobutanesulfonic acid (PFBS). Perfluorobutanoate is the conjugate base of perfluorobutanoic acid (PFBA). EXAMPLES

[0068] V. Working Examples

[0069] Example 1: Treatment of granular activated carbon

[0070] Two columns loaded with granular activated carbon (GAC) were prepared for breakthrough testing. The first column was loaded with untreated GAC ("No Pre-Treatment Lab F400" or "No Pre-Treatment GAC"). The second column was loaded with GAC that had been contacted with sodium hydroxide, hydrogen peroxide, aluminum hydroxide, calcium hydroxide, HCl, and DI water according to the protocol described below ("Pre-Treatment Lab F400" or "Pre-Treatment GAC").

[0071] Materials: Calgon F400 GAC was used in this study. GAC was sieved through 60×80 mesh. A column was equipped with a carbon bed made from GAC. The flow rate was set at 2.9 mL / min. Column ID: 1 cm. Bed height: 3-3.2 cm. Bed weight: 1.1-1.15 g.

[0072] Pretreated GAC was produced according to the following protocol: Take an Econo-Column and rinse with 50% ethanol and DI water. Rinse with DI water. Ensure that the bottom filter is intact. Fill the column with water and close the bottom valve. Pour 0.5 mm zirconia / silica beads into the bottom of the column, allowing the beads to spread 2-3 cm above the bottom filter. Tap gently to ensure the beads are well packed, then open the valve at the bottom of the column and drain the water. Rinse the blender with ethanol and water and fill it with fresh F400 GAC. Blend the GAC and wet sieve it through ASTM 60 and 80 mesh sieves. Dry the 80 mesh sieve to obtain 60 x 80 mesh fresh F400. Add approximately 1.1 g of 60 x 80 mesh fresh F400 to the column (use a spatula rinsed with ethanol). The column height should be 3 cm. Use a syringe to push water up from the bottom of the column and tap to ensure the GAC is well packed. Continue tapping and flushing with water until no air bubbles remain. Push the water up to 2 cm above the GAC. Add enough 0.5 mm zirconia / silica beads to fill to 1-2 cm above the PAC. Tap gently to ensure the beads are well packed. Add a piece of damp glass wool on top of the zirconia / silica beads, then attach a flow adapter to hold the contents of the column in place. Pump DI water through the column and allow the F400 to wet for several hours. Pump 250 mL of 1 M NaOH fluid through the column at 2.8 mL / min, followed by 250 mL of 12% food grade H2O2. Next, 2.5 L of 20 g / l Al(OH)3 / 10 g / L NaOH fluid is pumped through the column at 2.9 mL / min, followed by 2.5 L of 4 g / L Ca(OH)2 solution in the same ratio. Next, 0.5 L of 0.1 M HCl solution is pumped through the column at 2.9 mL / min. Finally, 2.5 L of DI water is pumped through the column at 2.9 mL / min. The regeneration rinse (Al(OH)3, NaOH, and Ca(OH)2), HCl rinse, and DI water rinse are repeated. The amount of DI water in the final rinse is increased to 6 L.

[0073] Approximately 20,000 BV of facility water was pumped through the columns of GAC without pretreatment and GAC with pretreatment, and samples were taken every approximately 1,000 BV (approximately 2500 mL).

[0074] Figure 1 shows the performance of an F400 GAC column with pretreatment versus an F400 GAC column without pretreatment when using PFOA as a representative PFAS compound.

[0075] The pretreated column showed breakthrough at approximately 7400 BV, whereas the non-pretreated column showed breakthrough at 1150 BV.

[0076] Other embodiments While the invention has been described in conjunction with its detailed description, it is to be understood that the foregoing description is illustrative and not limiting of the scope of the invention, which is defined by the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

1. 1. A method for treating carbon to improve its pollutant removal capacity, comprising: Carbon is dissolved in (a) hydroxide and / or peroxide, and (b) Ca ２＋ , Mg ２＋ , Zn ２＋ , Sr ２＋ , Al ３＋ , B ３＋ , and Fe ３＋ with one or more cations selected from: rinsing the carbon with an acidic aqueous solution, the acidic aqueous solution comprising hydrochloric acid, citric acid, sulfuric acid, or any combination thereof; The method comprising:

2. 10. The method of claim 1, wherein the (a) hydroxide and / or peroxide and the (b) one or more cations are provided in a single aqueous liquid or two or more separate aqueous liquids for contacting the carbon.

3. The method of claim 1 , wherein the (a) hydroxide and / or peroxide comprises sodium hydroxide or hydrogen peroxide.

4. The method of claim 1 , wherein the (a) hydroxide and / or peroxide comprises sodium peroxide.

5. The (b) one or more cations are Ca ２＋ The method of claim 1 , comprising:

6. The Ca ２＋ The method of claim 5 wherein is provided as calcium hydroxide.

7. The (b) one or more cations are Al ３＋ The method of claim 1 , comprising:

8. The Al ３＋ The method of claim 7, wherein is provided as aluminum sulfate, aluminum hydroxide, or sodium aluminate.

9. 2. The method of claim 1, wherein the (a) hydroxide and / or peroxide is provided in a first aqueous liquid and the (b) one or more cations are provided in a second aqueous liquid.

10. 10. The method of claim 9, wherein the first aqueous liquid is contacted with the one or more ionic contaminants before the second aqueous liquid, or the second aqueous liquid is contacted with the one or more ionic contaminants before the first aqueous liquid.

11. 10. The method of claim 1, further comprising contacting the carbon with (a) sodium hydroxide and / or hydrogen peroxide, and (b) calcium hydroxide, aluminum hydroxide, and / or aluminum sulfate.

12. 10. The method of claim 1, wherein the acid rinse occurs after the carbon has contacted the (a) hydroxide and / or peroxide and the (b) one or more cations.

13. The method of claim 1, further comprising rinsing the carbon with water, the water optionally being substantially free of additives.

14. 14. The method of claim 13, wherein the water rinse occurs after the carbon has contacted the (a) hydroxide and / or peroxide and the (b) one or more cations, and optionally after the acid rinse.

15. The method further comprising contacting the carbon with a surfactant; The surfactant is (i) a fatty acid, a sulfone, a phosphate, a polyether, a sulfate, a polyol, or any combination thereof; or (ii) sodium decyl sulfate (SDS), sorbitan monolaurate, polyethylene glycol (PEG), or any combination thereof The method of claim 1 , wherein the compound is selected from the group consisting of:

16. (i) before the (a) hydroxide and / or peroxide contacts the carbon, or (ii) after the (a) hydroxide and / or peroxide contacts the carbon; or (iii) while the (a) hydroxide and / or peroxide contacts the carbon, The method of claim 15 , wherein the surfactant contacts the carbon.

17. The method of claim 1, further comprising contacting the carbon with an antifreeze agent, wherein the antifreeze agent is selected from the group consisting of propylene glycol, polypropylene glycol, polyethylene glycol, glycerol, polyvinyl alcohol, carboxymethyl cellulose, ribose, sucrose, glucose, rhamnose, xylose, fructose, raffinose, stachyose, low molecular weight hydroxyethyl starch, maltodextrin, cellodextrin, and combinations thereof.

18. (i) before the (a) hydroxide and / or peroxide contacts the carbon, or (ii) after the (a) hydroxide and / or peroxide contacts the carbon; or (iii) while the (a) hydroxide and / or peroxide contacts the carbon, 18. The method of claim 17, wherein the antifreeze agent contacts the carbon.

19. The carbon is (i) is activated carbon, or (ii) comprises a powder, granule, bead, pellet, fabric, felt, nonwoven, or composite comprising a material selected from carbon, nitrogen-doped carbon, silicon-doped carbon, boron-doped carbon, charcoal, graphite, biochar, coke, carbon black, or any combination thereof; or (iii) comprising activated charcoal powder, granules, pellets, beads, or any combination thereof; or (iv) comprises sintered carbon; The method of claim 1.

20. The carbon is mixed with the (a) hydroxide and / or peroxide, and the (b) Ca ２＋ , Mg ２＋ , Zn ２＋ , Sr ２＋ , Al ３＋ , B ３＋ , and Fe ３＋ 10. The method of claim 1, wherein the compound is contacted with one or more cations selected from the group consisting of:

21. A treated carbon produced by the method of any one of claims 1 to 20.

22. The treated carbon of claim 21, wherein the carbon is porous.

23. The treated carbon of claim 22, wherein the carbon has a porosity of about 30% to about 95%.

24. The treated carbon of claim 21, further comprising a binder, the binder being selected from the group consisting of wax, starch, sugar, polysaccharide, or any combination thereof.

25. The treated carbon of claim 24, wherein the binder is a wax.

26. The treated carbon of claim 25, wherein the wax is polyethylene wax or carnauba wax.

27. Use of the treated carbon of claim 21 for capturing perfluoroalkyl and polyfluoroalkyl substances.

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