Adsorbent material, method for manufacture thereof, method of purifying a fluid mixture, and systems comprising adsorbent material

Abstract

An adsorbent material includes a plurality of polymer nanoparticles in the form of a network including inter-particle crosslinks. The polymer nanoparticles are formed from a block copolymer having a core-forming block and a shell-forming block, wherein the shell-forming block is capable of interacting with a target species and the core-forming block can facilitate phase separation to provide the polymer nanoparticle. The adsorbent material can be particularly useful for adsorption of a target species and subsequent regeneration due to the presence of dynamic covalent bonds in the network.

Description

ADSORBENT MATERIAL, METHOD FOR MANUFACTURE THEREOF, METHOD OF PURIFYING A FLUID MIXTURE, AND SYSTEMS COMPRISING THE ADSORBENT MATERIALCROSS-REFERENCE TO RELATED APPLICATIONThis application claims priority to U.S. Provisional Patent Application No. 63 / 700,103, filed on September 27, 2024, the contents of which are hereby incorporated by reference herein in their entirety.BACKGROUND

[0001] The global availability of clean drinking water has reached crisis levels especially in under-developed parts of the world with an estimated 844 million people lacking access to safe drinking water. Novel, sustainable approaches to water purification are now critical to combat this global issue. Traditionally, natural raw water is processed to decrease the concentration of natural and man-made pollutants to legal limits at centralized municipal plants and / or by the users at the point-of-use. Both centralized and point-of-use treatment rely on the same physicochemical principles to remove suspended and soluble constituents of the pollutants. One of the main premises of water treatment is concentrating pollutants on highly charged, high surface area solid surfaces (e.g., activated carbon, membrane, ion exchange resin). Since these adsorptive materials have a certain removal capacity, they exhaust their treatment ability in time. However, regeneration and reuse can minimize cost and environmental impact of water treatment.

[0002] Accordingly, there remains a continuing need in the art for new strategies for water purification. It would be particularly advantageous to provide a material which can be regenerated and reused.SUMMARY

[0003] An aspect of the present disclosure is an adsorbent material comprising a plurality of polymer nanoparticles, wherein the polymer nanoparticle comprises a block copolymer comprising a core-forming block and a shell-forming block, wherein the coreforming block is capable of phase separating from the shell-forming block; and the shellforming block is capable of interacting with a target species; and wherein the adsorbent materialfurther comprises inter-particle crosslinks comprising a dynamic covalent bond.

[0004] Another aspect is a method of making the adsorbent material, the method comprising: polymerization-induced self-assembly using light mediated atom transfer radical polymerization of a core-forming monomer from a shell-forming macroinitiator to provide a plurality of polymer nanoparticles; and curing of the polymer nanoparticles in the presence of a crosslinker to provide the adsorbent materials.

[0005] Another aspect is a method of purifying a fluid mixture comprising a target species, the method comprising: contacting the fluid mixture with the adsorbent material.

[0006] Another aspect is a filter cartridge assembly comprising: a cartridge comprising: a fluid inlet; a fluid outlet, and the adsorbent material positioned between the fluid inlet and the fluid outlet; and a housing surrounding the cartridge, the housing comprising a UV light source or sonication chamber.

[0007] The above described and other features are exemplified by the following figures and detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following figures are exemplary embodiments.

[0009] FIG. 1 shows one-pot synthesis of Nanoparticle Covalent Adaptable Network (NanoCAN) adsorbent materials combining nanoparticle formation and rapid, dynamic photocuring. A scanning electron microscope image (SEM image) is also shown.

[0010] FIG. 2 shows SEM images of exemplary adsorbents synthesized with cationic shell-forming blocks for the electrostatic removal of PFAS.

[0011] FIG. 3 shows PFOA adsorption isotherms for exemplary adsorbents fit to Langmuir (solid line) and Freundlich (dotted line) isotherm models.

[0012] FIG. 4 shows pseudo-second order kinetics of PFOA adsorption for exemplary adsorbents .

[0013] FIG. 5A shows removal of PS-MPs from aqueous solutions using an exemplary adsorbent with and without quatemized ammonium pendant groups showing less efficient removal kinetics.

[0014] FIG. 5B shows removal of PS-MPs from aqueous solutions using an exemplary adsorbent with and without quatemized ammonium pendant groups showing less efficient capacity.

[0015] FIG. 5C shows SEM imaging of the exemplary adsorbents post removal with the surface decorated with PS-MPs.

[0016] FIG. 6 shows simultaneous removal of PFOA and PS-MPs (c = 0.25 - 50 ppm) using exemplary adsorbents at constant adsorbent loading = 400 mg / L.

[0017] FIG. 7 shows regeneration protocols using UV-LED irradiation during water flushes and preliminary PFOA release experiments from saturated exemplary adsorbents compared to saturated, static materials with and without irradiation with UV-LED light strips (UV output power = 0.7 W / ft.; X = 365 mn).

[0018] FIG. 8 shows a schematic illustration of a filter cartridge according to an aspect of the present disclosure.

[0019] FIG. 9 shows a schematic illustration of a filter cartridge assembly and use for point-of-entry purification on a water faucet according to an aspect of the present disclosure.DETAILED DESCRIPTION

[0020] Domestic and municipal water treatment have been utilizing porous, high-surface area granular activated carbon (GAC) to remove pollutants from natural water sources. Once exhausted, spent GAC can be recovered to expand their life cycle and promote sustainable water treatment. At the municipal level, GACs can be regenerated after saturation via high temperature pyrolysis (-800 °C) followed by reactivation with oxidizing agents in controlled atmosphere to desorb and ideally decompose organic pollutants. This method, however, cannot be implemented for point-of-use (POU) or point-of-entry (POE) water treatment systems domestically or industrially causing the current commercial POU / POE adsorbents to be singleuse, disposable units. Thus, the development of regenerable adsorptive materials that can be safely regenerated after pollutant saturation using user-friendly procedures is in high demand towards benefiting water utilities and offering potential for use in POU / POE devices.

[0021] Per- and polyfluoroalkyl substances (PFAS) are a diverse class of 3,000+ anthropogenic compounds which are known for their unique amphiphilic properties and are used in applications ranging from stain and water repellents to fire suppressants. Their resistance to environmental, physiochemical and biochemical degradation instigated one of the most pronounced environmental concerns of the decade. In the U.S., the number of confirmed, contaminated public drinking water sources and military sites impacted by PFAS has more than tripled in the past 3-5 years mostly owing to the increased testing nationwide. U.S.Environmental Protection Agency (EP A) installed the Third Unregulated Contaminant Monitoring Rule (UCMR3) drawing attention to six PEAS species including PFOS, PFOA, PFNA, PFHxS, PFHpA and PFBS. Beyond these six species, so-called “GenX” derivatives of PFAS with perfluoroether functionalities have garnered attention recently. This contemporary water emergency has provided a need for the development of materials that can effectively remediate PFAS affected drinking water sources.

[0022] The present inventor has discovered that intrinsic self-healing of porous, adsorbent polymer networks can facilitate regeneration through stimuli-triggered pollutant desorption. This is accomplished using materials design combining in situ synthesis of morphology and chemically tunable polymer nanoparticles with one-pot, dynamic photo-curing procedures. For example, using bismethacrylate derivatives containing disulfide dynamic covalent bonds (DCBs), chemically tunable Nanoparticle Covalent Adaptable Network (NanoCAN) materials with interstitial porosity are provided, and are capable of disulfide metathesis in response to UV-A light irradiation (e.g., X = 365 nm) thereby facilitating adsorbent regeneration. In another advantageous feature, these materials can uniquely and efficiently remove PFAS contaminants using ion-exchange and are hypothesized to facilitate degradation of PFAS through UV- or ultrasound-induced thiol-radical formation allowing for on-resin deconstruction of the so-called “forever chemicals”. The described materials can address significant challenges that exist today related to disposal of PFAS-laden filter media (e.g, activated carbon) which pose a massive environmental hazard. A significant improvement is therefore provided by the present disclosure.

[0023] Accordingly, an aspect of the present disclosure is an adsorbent material. The adsorbent material comprises a plurality of polymer nanoparticles. The polymer nanoparticles are formed from assembly of block copolymers in solution. The block copolymer comprises a core-forming block and a shell-forming block. In an aspect, the block copolymer is a diblock copolymer comprising one core-forming block and one shell-forming block. Other block copolymer arrangements are also contemplated by the present disclosure (i.e., triblock copolymers, tetrablock copolymers, etc.).

[0024] The shell-forming block of the block copolymer is capable of interacting with a target species. In an aspect, the target species can be a pollutant in a fluid mixture, for example a per- or polyfluoroalkyl substance, microplastics, heavy metals, dyes, hydrophobic compounds, taste and odor affecting contaminants (e.g., 2-methylisobomeol (2-MIB) and geosmin) and thelike. In some aspects, the fluid mixture can comprise water.

[0025] In some aspects, the shell-forming block can be capable of interacting with a cationic target species, an anionic target species, or a hydrophobic target species. In an aspect, the shell-forming block can comprise cationic repeating units capable of interacting with an anionic species. For example, the shell-forming block can comprise repeating units comprising an ammonium group. In an aspect, the shell-forming block can comprise anionic repeating units capable of interacting with a cationic target species. For example, the shell-forming block can comprise repeating units comprising a sulfonate group. In an aspect, the shell-forming block can comprise hydrophobic repeating units capable of interacting with a hydrophobic target species. For example, the hydrophobic repeating units can comprise aromatic hydrocarbyl groups which are capable of pi-pi stacking with hydrophobic, aromatic-containing target species (e.g., polycyclic aromatic hydrocarbons such as naphthalene, 2-naphthol, phenanthrene, pyrene, and the like). For example, the shell-forming block can comprise repeating units comprising a naphthenyl group.

[0026] The shell-forming block can generally have a stronger affinity for the liquid in which they are formed (e.g., water) relative to the core-forming block in order to facilitate nanoparticle formation. In some aspects, the shell-forming block is a polar block or a hydrophilic block.

[0027] The core-forming block is selected such that it is capable of phase separation from the shell-forming block to facilitate formation of the polymer nanoparticles. In some aspects, the core-forming block can be further selected based on ability to interact with a selected target species. Without wishing to be bound by theory, it is believed that including a core-forming block that can further interact with the target species can provide improved adsorption of the target species in the adsorbent material. Exemplary core-forming block which can further interact with the target species can include, for example, repeating units capable of binding metals, or fluorinated groups for adsorption of fluorinated contaminants.

[0028] In some aspects, the core-forming block can comprise repeating units derived from a fluorinated monomer (e.g., a fluorinated aromatic group such as a pentafluorophenyl group) or a hydrophobic monomer (e.g., comprising a hydrocarbyl group, for example an aromatic group such as a benzyl group). In a specific aspect, the core-forming block can be derived from a monomer such as benzyl (meth)acrylate.

[0029] In a specific aspect, the core-forming block is derived from benzyl methacrylate;and the shell-forming block is derived from a monomer comprising an ammonium group, preferably poly(tetramethyl ammonium) ethyl methacrylate. Such a block copolymer may be particularly useful for adsorption of per- or polyfluoroalkyl substances, for example perfluorooctanesulfonic acid (PFOS), perfluorooctanesulfonic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), or a combination thereof.

[0030] The molar ratio of the core-forming block and the shell-forming block can be selected to provide a polymer nanoparticle having a desired morphology or size. In an aspect, the block copolymer can have a molar ratio of repeating units of the shell-forming block to repeating units of the core-forming block of 1 : 1 to 1 : 10, preferably 1 : 1.1 to 1 : 9, more preferably, 1 : 1.2 to 1 :8. Other molar ratios are also contemplated.

[0031] The block copolymer is capable of assembling into polymer nanoparticles. The polymer nanoparticles can vary in size, shape, and morphology, and such parameters can be tuned by varying molecular weight of the block copolymer, ratios of the core-forming block and the shell-forming block, and chemical identity of the core-forming block and the shell-forming block. For example, the polymer nanoparticles can be spherical, vesicles, worm-like micelles, or the like. In a specific aspect, the polymer nanoparticles are spherical.

[0032] In an aspect, the polymer nanoparticles can have an average size (e.g., diameter) of 0.05 to 10 micrometers, or 0.05 to 5 micrometers, or 0.05 to 1 micrometer, or 0.05 to 0.5 micrometers, or 0.1 to 10 micrometers, or 0.1 to 5 micrometers, or 0.1 to 1 micrometers, or 0.1 to 0.5 micrometers, or 0.5 to 10 micrometers, or 0.5 to 5 micrometers. It will be understood that when the polymer nanoparticles are non-spherical, average size or diameter refers to an average length of the longest dimension of the nanoparticle. Particle size can be determined using various techniques that are generally known. For example, particle size can be determined using imaging techniques such as scanning electron microscopy (SEM).

[0033] The polymer nanoparticles of the adsorbent material are crosslinked via interparticle crosslinks to form a network material. The network material can comprise a particular porosity. Advantageously, the inter-particle crosslinks comprise a dynamic covalent bond. As used herein, the term “dynamic covalent bond” refers to a covalent bond which can be broken or exchanged in response to a particular stimuli. Exemplary stimuli can include, but are not limited to, heat, ultra-violet (UV) light, sonication, and the like.

[0034] The dynamic covalent bond can be, for example, a disulfide bond, a Diels Alderadduct (e.g., derived from reaction of a maleimide and a furan), a coumarin dimer, or the like, or a combination thereof. In a specific aspect, the dynamic covalent bond can be a disulfide bond. Selection of a disulfide dynamic covalent linkage can be advantageous as full de-crosslinking is not required to regenerate the adsorbent material. Rather, the disulfide bonds are susceptible to exchange, and thus the integrity of the adsorbent material can be maintained during regeneration. Disulfide bonds can be further advantageous as they are multi-responsive. Stated another way, disulfide bonds can be susceptible to various stimuli including heat, ultra-violet irradiation, and sonication.

[0035] The inter-particle crosslinks can be formed by curing the polymer nanoparticles in the presence of a crosslinker which is capable of reacting with the polymer nanoparticles. For example, the crosslinker can comprise at least two reactive groups such as (meth)acrylates. In an aspect, the crosslinker can be a di(meth)acrylate. In a specific aspect, the crosslinker can be a di(meth)acrylate comprising a disulfide bond. For example, the crosslinker can be of the structure

[0036] The crosslinker can be present, for example, in an amount of 1 to 50 mole percent, or 1 to 30 mole percent, or 1 to 25 mole percent, or 1 to 20 mole percent, each based on moles of repeating units of the polymer nanoparticle (e.g., total of core-forming block, shellforming block, and crosslinker).

[0037] In a further advantageous feature, the present inventor has found that the particle morphology of the as-formed particles can be maintained even after inter-particle crosslinking. For example, spherical nanoparticles are generally maintained in their original spherical form even after crosslinking. This allows for the formation of a porous network structure, facilitating adsorption with high surface area capable of interacting with the target species.

[0038] A method for making the adsorbent material represents another aspect of the present disclosure. The method can comprise preparation of the block copolymer by polymerization induced self-assembly using light mediated atom transfer radical polymerization of a core-forming monomer from a shell-forming macroinitiator to provide a plurality of polymer nanoparticles. Exemplary polymerization conditions are further described in the working examples below.

[0039] In some aspects, the shell-forming macroinitiator can have a functional group at one chain end (i.e., at the terminal end of the shell-forming block which does not participate in formation of the core-forming block). The functional group, when present, can be selected to further functionalized the periphery of the polymer nanoparticles, if desired. For example, in a specific aspect, the polymer nanoparticles can comprise an alkyne group at the periphery of the nanoparticle due to use of an alkyne-terminated shell-forming block. The polymer nanoparticle comprising an alkyne group can be further functionalized, for example using click chemistry. Other functional groups are also contemplated by the present disclosure.

[0040] Preferably, the polymerization is conducted at high solids content in order to facilitate assembly and crosslinking of the polymer nanoparticles. The polymerization can also be conducted in a solvent which is selective for the shell- forming block to facilitate the desired formation of the core-shell nanoparticle.

[0041] The method further comprises curing of the polymer nanoparticles in the presence of a crosslinker to provide the adsorbent material. The curing can be under conditions effective to crosslink the nanoparticles. In an aspect, the curing can be a photocuring process comprising irradiating a mixture of the nanoparticles in the presence of the crosslinker. The irradiating can be using a wavelength of light effective to initiate crosslinking and can be selected by the skilled person based on the chemical identity of the block copolymer and the crosslinker.

[0042] The adsorbent material described herein can be particularly useful for purifying fluid mixtures, for example water purification. A method of purifying a fluid mixture can comprise contacting the fluid mixture comprising a target species (i.e., a pollutant) with the adsorbent material. The target species can be as described above, for example a PFAS, a heavy metal, microplastics, and the like. In some aspects, the contacting can be for a time effective to remove at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95% of the target species from the fluid mixture.

[0043] Advantageously, the adsorbent material can be regenerated after adsorption of the target species. Stated another way, the adsorbent material comprising adsorbed target species can be subjected to conditions effective to desorb the target species from the adsorbent material. For example, the adsorbent material can be heated (e.g., to a temperature of 100 °C or less), exposed to ultra-violet light, or exposed to sonication. The particular trigger to cause desorption can be selected based on the identity of the particular dynamic covalent bonds present in theadsorbent material.

[0044] In a specific aspect, when the dynamic covalent bonds of the adsorbent material comprise disulfide bonds, removing the target species from can comprise exposing the adsorbent material comprising adsorbed target species to ultraviolet irradiation or sonication to effect disulfide bond scission and provide thiol radicals in the adsorbent material. A fluid (e.g., water) can be passed through the adsorbent material to remove the target species. Passage of the fluid can be concurrent with or subsequent to the exposure to ultraviolet irradiation or sonication. Advantageously, high temperatures are not required for desorption using the adsorbent material according to the present disclosure.

[0045] The adsorbent material described herein can be particularly useful for water purification, for example in point-of-entry (POE) or point-of-use (POU) water purification in commercial and domestic settings using a cartridge-based filter assembly. Accordingly, a filter cartridge assembly represents another aspect of the present disclosure.

[0046] The filter cartridge assembly comprises a cartridge comprising a fluid inlet, a fluid outlet, and the adsorbent material of the present disclosure positioned between the fluid inlet and the fluid outlet. The adsorbent material can be provided within a contained that is optically transparent (e.g., transparent to ultraviolet irradiation, such as at a wavelength of 365 nanometers). The fluid inlet, the fluid outlet, or both can comprise a porous membrane for further filtration of larger particulates. An exemplary cartridge is shown in FIG. 8. It will be understood that the fluid inlet porous membrane is depicted with 450 nanometer pores, however other pore sizes are contemplated by the present disclosure and can be selected appropriately based on the specific application of the cartridge.

[0047] The filter cartridge assembly further comprises a housing surrounding the cartridge. The housing comprises an ultraviolet light source, a sonication chamber, or both. The housing can further comprise a power source, such as a battery. An exemplary assembly including the housing is depicted in FIG. 9. The fluid inlet of the cartridge can be capable of attaching to a home water inlet, a faucet, a pitcher, or a refrigerator for water filtration.

[0048] This disclosure is further illustrated by the following examples, which are nonlimiting.EXAMPLES

[0049] In the synthesis of the materials of the present disclosure, one-pot polymerization,self-assembly, and in situ core and inter-nanoparticle crosslinking provides a scalable and tunable methodology for various adsorbents. These adsorbent materials possess unique interstitial porosity for pollutant capture and can be synthesized in a divergent manner altering the shell-forming methacrylate (MA) monomers, core-forming MAs, molecular weight (MW) of both block copolymer segments (to alter the nanoparticle morphology in situ), and crosslink density to generate a family of adsorbent materials. Incorporation of shell- or core-forming monomers with complementary functionalities can facilitate targeted adsorption properties via tailored intermolecular interactions between adsorbent and different classes of structurally related and environmentally significant adsorbates (e.g., PFAS, heavy metals, or hydrophobic pollutants). The responsive nature of disulfide crosslinks has been shown to imbue regenerability through UV-induced network reconfiguration.

[0050] The following examples describe synthesis of adsorbents, assessment of the efficacy of the adsorbents with and without complementary functional groups in the adsorption of five different PFAS pollutants with different chain lengths (z.e., 4 - 8 carbons) and polar functionalities (z.e., carboxylic acids, sulfonic acids, perfluoroether), and investigation of the stimuli-induced degradation and release of PFAS using UV or ultrasound (z.e., sonochemical) treatments coupled with water washes.

[0051] A one-pot synthesis of adsorbent materials according to an aspect of the present disclosure is depicted in FIG. 1. Synthesis of the adsorbents is accomplished via divergent synthetic pathways in two, one-pot steps using commercially available MA monomers starting with PhotoATR-PISA fabrication of polymer nanoparticles with different morphologies. Corecrosslinking (CCL) of nanoparticles is accomplished simultaneously with inter-nanoparticle crosslinking and gel formation providing a streamlined, rapid methodology for adsorbent fabrication.

[0052] The divergent synthesis for these materials starts with macroinitiator formation allowing for tunable shell chemistries using different monomers with polar pendant groups. Furthermore, different macroinitiator MW can be implemented for subsequent steps. Growth of solvophobic second blocks from macroinitiators using functional, hydrophobic MA monomers provides scalable, in situ formation of polymer nanoparticles with tunable morphologies at high solids contents. These are then photo-cured with bismethacrylate crosslinkers to form adsorbents. PFAS-targeting adsorbents have been fabricated with varied incorporation of complementary, basic shell-forming monomers (z.e., 7V,7V-dimethylaminoethylmethacrylate orDAMA) and fluorinated core-forming monomers (i.e., heptafluorobutylmethacrylate or FBMA) into adsorbent materials to investigate their influence on adsorption of perfluorooctanoic acid(PFOA). These functional monomers can be replaced with non-compl ementary shell- and coreforming monomers such as oligo(ethylene glycol)methacrylate (OEGMA) and benzyl methacrylate (BMA), respectively, allowing for detailed mechanistic investigations into their influence on tailored adsorption properties. Furthermore, the degree of polymerization (i.e., number of repeat units; DP) for shell and core forming blocks can be systematically altered to investigate the influence of core-to-shell ratio and nanoparticle morphology on adsorption properties for adsorption optimization. Table 1 shows MA monomers to be incorporated into functional, cationic (+), anionic (-) and hydrophobic (H) adsorbents with complementary (C) and non-complementary (NC) pendant groups and varied block copolymer degree of polymerization(DP) for targeted removal of pollutants (CL = crosslinker).Table 1

[0053] The DP was altered for preliminary core-forming blocks starting with eitherPDAMA or POEGMA macroinitiators showing clear alterations to nanoparticle morphology and size when visualized using scanning electron microscopy (SEM). This morphological tunabilityis hypothesized to provide variable porosity within adsorbent materials. The installation of disulfide crosslinks using disulfide dimethacrylate (DSDMA) provides dynamic network characteristics which are utilized for adsorbent regeneration. Finally, the basic amines in PDAMA blocks have also been methylated using methyl iodide following adsorbent synthesis forming permanently, cationic ion-exchange adsorbents (z.e., NanoCAN(+)). NanoCAN-1 - 6(+) have been successfully synthesized and implemented for adsorption experiments. The analogous control adsorbents have also been fabricated using crosslinkers without disulfides (z.e., hexanediol dimethacrylate or HDDMA) to demonstrate the role of network reconfiguration on regeneration.

[0054] The divergent synthetic approach for all NanoCANs allows for facile alterations in shell copolymer MW (ca. DP(x) = 40 - 80), core copolymer MW (ca. DP(y) = 100 - 300) and crosslink density (ca. DP(z) = 10 - 30) allowing for detailed mechanistic investigations into structure-property relationships in the context of adsorption. Like before, the incorporation of complementary, shell- and core-forming MA monomers for targeted adsorption will be altered using non-complementary monomers (z.e., OEGMA, BMA) to ascertain their influence on adsorption properties.

[0055] The adsorbents of the present disclosure can be chemically designed to tailor adsorption properties via targeted intermolecular interactions (e.g., electrostatics, metal complexation, K-K interactions) allowing for the enhanced removal of anionic, fluorous, cationic, and hydrophobic pollutants with high adsorption capacities. Three specific classes of pollutants will be studied including anionic (e.g, PFAS), cationic (e.g., heavy metals) and hydrophobic (e.g., PAHs, 2-M1B, geosmin). Combining NanoCAN materials in mixed-bed columns will also be investigated using mixtures of contaminants under realistic water treatment conditions.

[0056] To quantify PFAS removal, an optical assay to measure PFAS concentration efficiently using UV-Vis spectroscopy was developed. This method uses methyl violet (MV) as a reporter molecule for PFAS via charge complexation between the positively charged MV dye and negatively charged PFAS molecules. Upon complexation, the charge paired adduct can transfer phases from aqueous to ethyl acetate (organic) layers allowing for facile quantification of PFAS concentration. Calibration curves for the MV-UV assay were conducted for 4 PFAS derivatives (PFOA, PFOS, PFBA and GenX) to ascertain the limits of detection and quantification (LOD and LOQ, respectively) possible with the described assay. Overall, with the exception of PFBA, all PFAS derivatives displayed nice linear fits for calibration curves inconcentration ranges from 10 ppb to 2.5 ppm and were conducted in triplicate showing excellent coherence and reproducibility amongst runs. Furthermore, the MV-UV assay proved relatively sensitive with LOD = 150 ppb and LOQ = 500 ppb, respectively.

[0057] Four adsorbent materials were synthesized: NanoCAN-1 (n=80, m=l 00; see FIG. 1); NanoCAN-2 (n=80, m=300, see FIG. 1); NanoCAN-3 (n=40, m=100; see FIG. 1); and NanoCAN-4 (n=40, m=300; see FIG. 1). The SEM images of the four synthesized NanoCAN derivatives are displayed in FIG. 2. Altering the degree of polymerization (DP) in either the shell-forming (z.e., ionic, poly(tetramethyl ammonium ethyl methacrylate) block) or hydrophobic, core-forming (z.e., poly(benzyl methacrylate) block) copolymer segments lead to changes in polymer nanoparticle size as evidenced by microscopy analysis. This leads to alterations in porosity and surface area for the NanoCAN derivatives, with additional implications in adsorption capabilities. In all cases, the observed materials via SEM appeared to have significant porosity leading to their hypothesized adsorption properties.

[0058] Using the described MV-UV assay, perfluorooctanoic acid (PFOA) adsorption experiments using NanoCAN-1 and NanoCAN-3 were performed, investigating adsorption kinetics (adsorbent loading = 180 mg / L; [PFOA] = 1 - 200 ppm) and constructing adsorption isotherms to quantify adsorption capacity (Qmax based on Langmuir-isotherm data fits). At all concentrations, equilibrium was reach within 2 hours and, in many cases, within 45 minutes demonstrating the speed of removal. Based on these experiments, NanoCAN-1, with greater positive charge character, displayed vastly enhanced adsorption capacity with Qmax = 320 mg / g compared to Qmax = 84.6 mg / g for NanoCAN-3. Kinetic analysis for PFOA removal comparing these same two NanoCAN derivatives was performed at two concentrations (ca. 1.0 ppm and 155 ppm) and also demonstrated superior performance for NanoCAN-1. NanoCAN-1 showed ~1 lx faster adsorption rates with fit to pseudo-second order rate laws. This provides clear evidence that that increasing the DP of cationic, shell-forming blocks (z.e., increasing the total quantity of cationic groups) can provide substantial increases in PFOA adsorption capabilities. The PFOA adsorption isotherms for NanoCAN-1 and -3 are shown in FIG. 3 and 4.

[0059] The cationic nature of these derivatives also led to investigation of a dual-use of such gels in the removal of microplastic and nanoplastic derivatives, which typically have negative surface charges after natural weathering processes. Furthermore, the simultaneous removal of PFOA and microplastics from spiked aqueous solutions was investigated with NanoCAN-1. To study this, fluorescently-labelled polystyrene microspheres with carboxylatefunctionalities decorated on the surface (PS-MP) were used as microplastic mimics and their removal from aqueous solutions was monitored by fluorescence spectroscopy. Overall, the effect of quatemization for pendant amines in adsorbent materials was first investigated for the removal of microplastics alone, both by kinetic and isotherm analysis (FIG. 5). The neutral NanoCAN- l(n) prior to quatemization showed lesser capabilities in removing PS-MPs (c = 100 ppm; NanoCAN loading = 180 mg / L) leading to modest equilibrium removal efficiencies (RE) = ~63% within 1 h. In contrast, after quatemization, NanoCAN-1, with permanently cationic functional groups, was highly effective at removing PS-MPs from aqueous dispersions leading to RE = 98% after only 30 minutes. This observation is further translated to the overall adsorption capacity of the NanoCAN derivatives with ultra-high removal capabilities for NanoCAN- 1 (ca. Qmax = 1111 mg / g). It should be noted that this capacity was calculated using Langmuir isotherm fits which may not be strictly appropriate for such adsorption mechanisms but at least can provide some estimation of removal capacities in the context of PS-MPs. Uniquely, even at very high concentrations of PS-MPs (ca. 1000 ppm), the removal efficiencies remained at values >95% exemplifying the ultra-high capacities of these gels for removing MPs. When imaging the gels post removal experiments with ca. 1000 ppm dispersions of PS-MPs using scanning electron microscopy (SEM), the adhesion of PS-MPs to NanoCAN surfaces is highly apparent demonstrating the strong interactions between the adsorbents and MPs.

[0060] Additional experiments were also conducted to demonstrate the simultaneous removal of PS-MPs and PFOA over a range of concentrations (ca. 0.25 - 50 ppm for each) to demonstrate dual-use capabilities (FIG. 6). The cationic nature of NanoCAN derivatives allows for the successful capture of microplastics via NanoCAN surface interactions and PFAS via pore-capture and electrostatic complexation. This was demonstrated over a range of pollutant concentrations in mixed systems showing efficient removal of PS-MPs (ca. RE = 88 - 99%) and PFOA (ca. RE = 50 - 87%) over the range of concentrations studied.

[0061] PFAS adsorption kinetics experiments were conducted for PFOS, GenX and PFBA, compared to PFOA (all at c = 1.0 ppm; adsorbent loading = 400 mg / L), to ascertain the generality of these materials for PFAS remediation (Table 2). PFOA and PFOS were both effectively adsorbed using NanoCAN- 1 adsorbents showing RE > 90% after 60 min and 45 min, respectively. GenX and PFBA, having shorter fluorocarbon chains and higher water solubility showed lower removal efficiencies. For GenX, adsorption was still relatively efficient leading to RE = 69% after 45 min. PFBA proved far more challenging for removal with only RE = 8.1%after 45 min.Table 2PFOA* Time (min) Cone. (mg / L) % RemovalT1 0 0.896T2 30 0.150 83.25T3 60 0.092 89.69PFOS Time (min) Cone. (mg / L) % RemovalT1 0 2.356T2 15 0.333 85.84T3 45 0.137 94.19GenX Time (min) Cone. (mg / L) % RemovalT1 0 2.139T2 15 0.823 61.53T3 45 0.663 68.98HFBA Time (min) Cone. (mg / L) % RemovalT1 0 2.101T2 15 1.962 6.61T3 45 1.930 8.12

[0062] Finally, the UV-induced release of PFOA from saturated NanoCAN-1 gels was accomplished and compared to control gels synthesized in the same fashion as NanoCANs but without disulfide DCBs (FIG. 7). For this experiment, saturated gels were added to a small glass column wrapped with UV-LED strips (UV output power = 0.7 W / ft; Xmax = 365 nm). These materials were irradiated for short durations (ca. 2 min) during D.I. water flushes and the eluent was analyzed by MV-UV assays. Further, as another control, the same process was repeated in the absence of UV light to demonstrate the role of light on initiating dynamic disulfide metathesis. Overall, only this process proved successful with the only gel that demonstrated release being the dynamic NanoCAN-1 gel under irradiation.

[0063] The present inventor has demonstrated capabilities of PFAS removal for three different PFAS derivatives with different chemical functionalities (z.e., PFOA, PFOS, GenX). Adsorption isotherms were measured for PFOA removal using two NanoCAN derivatives showing enhanced removal for NanoCAN-1 materials with larger numbers of cationic ammonium groups. This same observation was also observed when applying these NanoCAN materials for removal of PS-MPs from aqueous solutions. NanoCAN-1 showed highly effective removal of PS-MPs with negative surface charge demonstrating ultra-high adsorption capacities (ca. Qmax = 1111 mg / g). Further, simultaneous removal of PS-MPs and PFOA was demonstrated over a range of contaminant concentrations. This is hypothesized to be facilitated by the strongsurface and electrostatic interactions between both PFOA and PS-MPs with NanoCAN materials. Finally, experiments on UV-induced release of PFOA from saturated NanoCAN gels were conducted providing clear evidence that the UV-A light irradiation does facilitate release. A significant improvement is therefore provided by the present disclosure.

[0064] This disclosure further encompasses the following aspects.

[0065] Aspect 1 : An adsorbent material comprising a plurality of polymer nanoparticles, wherein the polymer nanoparticle comprises a block copolymer comprising a core-forming block and a shell-forming block, wherein the core-forming block is capable of phase separating from the shell-forming block; and the shell-forming block is capable of interacting with a target species; and wherein the adsorbent material further comprises inter-particle crosslinks comprising a dynamic covalent bond.

[0066] Aspect 2: The adsorbent material of aspect 1, wherein the core-forming block is derived from a fluorinated monomer or a hydrophobic monomer.

[0067] Aspect 3: The adsorbent material of aspect 1 or 2, wherein the core-forming block is derived from benzyl methacrylate.

[0068] Aspect 4: The adsorbent material of any of aspects 1 to 3, wherein the coreforming block is further capable of interacting with the target species.

[0069] Aspect 5: The adsorbent material of any of aspects 1 to 4, wherein the shellforming block is capable of interacting with a cationic target species, an anionic target species, or a hydrophobic target species.

[0070] Aspect 6: The adsorbent material of any of aspects 1 to 5, wherein the shellforming block is derived from a monomer comprise an ammonium group, a sulfonate group, or a naphthenyl group.

[0071] Aspect 7: The adsorbent material of any of aspects 1 to 6, wherein the interparticle crosslinks comprising a dynamic covalent bond comprise disulfide bonds.

[0072] Aspect 8: The adsorbent material of any of aspects 1 to 7, wherein the interparticle crosslinks are formed using a crosslinker comprising a disulfide bond.

[0073] Aspect 9: The adsorbent material of aspect 8, wherein crosslinker is a di(meth)acrylate comprising a disulfide bond.

[0074] Aspect 10: The adsorbent material of aspect 8 or 9, wherein the crosslinker is of the structure

[0075] Aspect 11 : The adsorbent material of aspect 1, wherein the core-forming block is derived from benzyl methacrylate; and the shell-forming block is derived from a monomer comprising an ammonium group, preferably poly(tetramethyl ammonium) ethyl methacrylate.

[0076] Aspect 12: The adsorbent material of any of aspects 1 to 11, wherein the target species is a per- or polyfluoroalkyl substance, preferably perfluorooctanesulfonic acid (PFOS), perfluorooctanesulfonic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), or a combination thereof.

[0077] Aspect 13: The adsorbent material of any of aspects 1 to 12, wherein each of the plurality of nanoparticles has an average diameter of 0.05 to 10 micrometers.

[0078] Aspect 14: The adsorbent material of any of aspects 1 to 13, wherein the block copolymer comprises a molar ratio of repeating units of the shell-forming block to repeating units of the core-forming block of 1 : 1 to 1 : 10, preferably 1 : 1.1 to 1 : 9, more preferably, 1 : 1.2 to 1:8.

[0079] Aspect 15: A method of making the adsorbent material of any of aspects 1 to 14, the method comprising: polymerization induced self-assembly using light mediated atom transfer radical polymerization of a core-forming monomer from a shell-forming macroinitiator to provide a plurality of polymer nanoparticles; and curing of the polymer nanoparticles in the presence of a crosslinker to provide the adsorbent materials.

[0080] Aspect 16: A method of purifying a fluid mixture comprising a target species, the method comprising: contacting the fluid mixture with the adsorbent material of any of aspects 1 to 14.

[0081] Aspect 17: The method of aspect 16, further comprising removing the target species from the adsorbent material to regenerate the adsorbent material.

[0082] Aspect 18: The method of aspect 17, wherein removing the target species comprises exposing the adsorbent material comprising adsorbed target species to ultraviolet irradiation or sonication to effect disulfide bond scission and provide thiol radicals in the adsorbent material, and passing a fluid through the adsorbent material to remove the target species.

[0083] Aspect 19: A filter cartridge assembly comprising: a cartridge comprising: a fluid inlet; a fluid outlet, and the adsorbent material of any of aspects 1 to 14 positioned between the fluid inlet and the fluid outlet; and a housing surrounding the cartridge, the housing comprising a UV light source or sonication chamber.

[0084] Aspect 20: The filter cartridge assembly of aspect 19, wherein the fluid inlet is capable of attaching to a home water inlet, a faucet, a pitcher, or a refrigerator

[0085] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles.

[0086] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. “Combinations” is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms “first,” “second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” and “the” do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and / or” unless clearly stated otherwise. Reference throughout the specification to “an aspect” means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term “combination thereof’ as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements not named. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0087] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0088] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflictswith a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0089] Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency filled by a bond as indicated, or a hydrogen atom. A dash that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -CHO is attached through carbon of the carbonyl group.

[0090] Unless substituents are otherwise specifically indicated, each of the foregoing groups can be unsubstituted or substituted, provided that the substitution does not significantly adversely affect synthesis, stability, or use of the compound. “Substituted” means that the compound, group, or atom is substituted with at least one (e.g., 1, 2, 3, or 4) substituents instead of hydrogen, where each substituent is independently nitro (-NO2), cyano (-CN), hydroxy (-OH), halogen, thiol (-SH), thiocyano (-SCN), Ci-e alkyl, C2-6 alkenyl, C2-6 alkynyl, C1-6 haloalkyl, C1.9 alkoxy, Ci-e haloalkoxy, C3-12 cycloalkyl, C5-18 cycloalkenyl, Ce-12 aryl, C7-13 arylalkylene (e.g., benzyl), C7-12 alkylarylene (e.g, toluyl), C4-12 heterocycloalkyl, C3-12 heteroaryl, Ci-e alkyl sulfonyl (-S(=O)2-alkyl), Ce-i2 arylsulfonyl (-S(=O)2-aryl), or tosyl (CH3C6H4SO2-), provided that the substituted atom’s normal valence is not exceeded, and that the substitution does not significantly adversely affect the manufacture, stability, or desired property of the compound. When a compound is substituted, the indicated number of carbon atoms is the total number of carbon atoms in the compound or group, including those of any substituents.

[0091] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

Claims

CLAIMS1. An adsorbent material comprising a plurality of polymer nanoparticles, wherein the polymer nanoparticle comprises a block copolymer comprising a core-forming block and a shell-forming block, wherein the core-forming block is capable of phase separating from the shell-forming block; and the shell-forming block is capable of interacting with a target species; and wherein the adsorbent material further comprises inter-particle crosslinks comprising a dynamic covalent bond.

2. The adsorbent material of claim 1 , wherein the core-forming block is derived from a fluorinated monomer or a hydrophobic monomer.

3. The adsorbent material of claim 1 , wherein the core-forming block is derived from benzyl methacrylate.

4. The adsorbent material of claim 1 , wherein the core-forming block is further capable of interacting with the target species.

5. The adsorbent material of claim 1 , wherein the shell-forming block is capable of interacting with a cationic target species, an anionic target species, or a hydrophobic target species.

6. The adsorbent material of claim 1 , wherein the shell-forming block is derived from a monomer comprise an ammonium group, a sulfonate group, or a naphthenyl group.

7. The adsorbent material of claim 1 , wherein the inter-particle crosslinks comprising a dynamic covalent bond comprise disulfide bonds.

8. The adsorbent material of claim 1 , wherein the inter-particle crosslinks are formed using a crosslinker comprising a disulfide bond.

9. The adsorbent material of claim 8, wherein crosslinker is a di(meth)acrylate comprising a disulfide bond.

10. The adsorbent material of claim 8, wherein the crosslinker is of the structure11. The adsorbent material of claim 1 , wherein the core-forming block is derived from benzyl methacrylate; and the shell-forming block is derived from a monomer comprising an ammonium group, preferably poly(tetramethyl ammonium) ethyl methacrylate.

12. The adsorbent material of claim 1 , wherein the target species is a per- or polyfluoroalkyl substance, preferably perfluorooctanesulfonic acid (PFOS), perfluorooctanesulfonic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), or a combination thereof.

13. The adsorbent material of claim 1 , wherein each of the plurality of nanoparticles has an average diameter of 0.05 to 10 micrometers.

14. The adsorbent material of claim 1 , wherein the block copolymer comprises a molar ratio of repeating units of the shell-forming block to repeating units of the core-forming block of 1 : 1 to 1 : 10, preferably 1 : 1.1 to 1 :9, more preferably, 1 : 1.2 to 1 :8.

15. A method of making the adsorbent material of claim 1, the method comprising: polymerization induced self-assembly using light mediated atom transfer radical polymerization of a core-forming monomer from a shell-forming macroinitiator to provide a plurality of polymer nanoparticles; and curing of the polymer nanoparticles in the presence of a crosslinker to provide the adsorbent materials.

16. A method of purifying a fluid mixture comprising a target species, the method comprising: contacting the fluid mixture with the adsorbent material of claim 1.

17. The method of claim 16, further comprising removing the target species from the adsorbent material to regenerate the adsorbent material.

18. The method of claim 17, wherein removing the target species comprises exposing the adsorbent material comprising adsorbed target species to ultraviolet irradiation or sonication to effect disulfide bond scission and provide thiol radicals in the adsorbent material, and passing a fluid through the adsorbent material to remove the target species.

19. A filter cartridge assembly comprising: a cartridge comprising: a fluid inlet; a fluid outlet, and the adsorbent material of claim 1 positioned between the fluid inlet and the fluid outlet; and a housing surrounding the cartridge, the housing comprising a UV light source or sonication chamber.

20. The filter cartridge assembly of claim 19, wherein the fluid inlet is capable of attaching to a home water inlet, a faucet, a pitcher, or a refrigerator.

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