3D printed porous supramolecular sorbents

Abstract

Porous polymers known for their high surface area, tunable pore size, and adsorption capabilities were explored for cobalt recycling using a supramolecular receptor and photocurable porous polymer. A porous polymer structure includes a nanoporous polymer matrix having repeating units derived from a receptor monomer and optionally, a support monomer, wherein the nanoporous polymer matrix comprises a plurality of nanopores having an average pore diameter of 1 to 1000 nanometers. Methods for the manufacture of porous polymer structures and methods of binding a target metal species are also described.

Description

3D PRINTED POROUS SUPRAMOLECULAR SORBENTSCROSS REFERENCE TO RELATED APPLICATIONThis application claims priority to U.S. Provisional Application No. 63 / 531,908, filed on August 10, 2023, the content of which is hereby incorporated by reference in its entirety.FEDERAL RESEARCH STATEMENTThis invention was made with government support under Grant no. 2045336 awarded by the National Science Foundation, and under Grant no. DE-SC0024393 awarded by the U.S. Department of Energy Office of Basic Energy Sciences. The government has certain rights in the invention.BACKGROUND

[0001] Cobalt is an essential element required for a range of technologies such as, e.g., electric vehicles. It is also a critical material that suffers from international supply chain instability. Exacerbating the availability problem is that over 70% of cobalt production occurs in the Democratic Republic of Congo (DRC), where mining and refinement practices are detrimental to both human health and the environment. Recycling cobalt from end-of-life waste offers a possible self-sufficient and sustainable solution to these issues. Conventional metallurgical recycling approaches rely primarily on liquid-liquid extraction (LLE) using phosphorus-containing ligands, such as Cyanex 272, a dialkyl phosphinic acid. Although effective, third phase formation (i.e., emulsion), secondary waste generation, and loss of extractant limits the widespread use of LLE for cobalt recycling. Thus, alternatives to LLE that require fewer processing steps, minimize waste, and enhance extractant reuse are needed.SUMMARY

[0002] A porous polymer structure comprises a nanoporous polymer matrix comprising repeating units derived from a receptor monomer capable of bonding with a metal, and optionally, a support monomer; wherein the nanoporous polymer matrix comprises a plurality of nanopores having an average pore diameter of 1 to 1000 nanometers.

[0003] A method for the manufacture of the porous polymer structure comprises: providing a resin mixture comprising: the receptor monomer; optionally, the supportmonomer; a photoinitiator; and a porogen; and irradiating the resin mixture with light to provide the porous polymer structure.

[0004] A method of binding a target metal species comprises: contacting a fluid mixture comprising the target metal species with the porous polymer structure.

[0005] A system for removing a target metal species from a fluid mixture comprises: a feed vessel comprising the fluid mixture comprising the target metal species and having an inlet and an outlet; a pump in fluid communication with the outlet of the feed vessel wherein the pump is capable of conveying the fluid mixture to a cartridge comprising the porous polymer structure; wherein an outlet of the cartridge is fluidly connected to the inlet of the feed vessel.

[0006] The above described and other features are exemplified by the following figures and detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The following figures represent exemplary embodiments.|0008| FIG. 1 is a schematic illustration of a 3D printed structured supramolecular sorbents that can selectively bind and release C0CI2.

[0009] FIG. 2 shows chemical structures of exemplary resin components according to an aspect of the present disclosure.

[0010] FIG. 3 shows a depiction of film transmittance measurements and a ternary plot showing the resin formulations that either do or do not undergo polymerization induced phase separation (PIPS). Selected resin formulations containing 1 :1 porogens to TPGDA are indicated. Images of the films prepared with a range of cyclohexanol to 1 -decanol ratios and the no-porogen control are also shown.

[0011] FIG. 4 shows a representative image and analysis for a 0:1 cyclohexanol to 1- decanol sample using SEM and Imaged. Bar chart with average pore diameters (nm) for resins prepared with 1 :0 to 0:1 cyclohexanol to 1 -decanol ratios. Pore diameters are averages from three trials with error bars representing one standard deviation from the mean.

[0012] FIG. 5 shows a schematic representation of DLP 3D printing that contains a light emitting diode (LED), digital mirror device (DMD), vat with liquid resin, and build platform.

[0013] FIG. 6 shows representative images of printed and critical point dried (CPD) kelvin lattice, gyroid, and cube (10 mmx 10 mm x 10 mm), prepared from resins containing a0:1 cyclohexanol to 1-decanol ratio. Average compression testing elastic moduli of cubes (5 mm x 5 mm x 5 mm) prepared with different porogen ratios is shown. Moduli values are averages from three trials with one standard deviation from the mean provided. Scanning electron microscopy (SEM) images of the kelvin lattice (10 mmx 10 mm x 10 mm) prepared with 0:1 cyclohexanol to 1-decanol ratio are also shown.

[0014] FIG. 7 shows an illustration of the process used to determine ion binding via conductivity measurements.

[0015] FIG. 8 shows binding isotherms for CoCF and LiCl in various solvents, with uptake provided as millimoles of ions relative to grams of bulk sorbent. Dashed lines represent fits to a non-linear Freundlich model. Symbols represent averages from three trials with error bars representing one standard deviation from the mean.

[0016] FIG. 9 shows digital camera images of a kelvin lattice comprising 5 mol%- BDCA before and after C0CI2 binding in a 25 mM EtOH solution (top). SEM-EDX mapping images for Co and Cl on the sorbent surface (bottom).

[0017] FIG. 10 shows representative kinetic adsorption isotherms measured using UV-vis absorption spectroscopy. Symbols provided are indexed for clarity and the dashed lines represent a non-linear pseudo-first order fit. Rate constants (ki ) were determined from an average of three trials with error representing one standard deviation from the mean.

[0018] FIG. 11 shows equilibrium uptake as a function of receptor loading and pore size for kelvin lattices.

[0019] FIG. 12 shows equilibrium uptake as a function of 3D microstructure. Data provided are averages from three trials with error bars representing one standard deviation from the mean. SA:V, surface area to volume ratio.

[0020] FIG. 13 shows an illustration and experimental data for cyclic catch-and- release experiments. Release percentage is relative to the amount of C0CI2 bound in that same cycle.

[0021] FIG. 14 shows an illustration and experimental data for Co2+over Li+selectivity. All data are the averages of three independent trials with error bars representing one standard deviation from the mean.

[0022] FIG. 15 shows a schematic illustration of a flow setup for purifying and in situ monitoring of leachate from NdFeB magnets that contain Nd, Dy, and Co.DETAILED DESCRIPTION

[0023] Immobilized receptors combine ease of reuse with tunable selectivity and affinity, making them an attractive platform for critical material recycling. Furthermore, non- covalent (e.g., ionic) interactions with supramolecular receptors are highly dependent on environmental factors, such as solvent polarity, which enables on-demand bind-and-release. Recently, such an approach has been investigated for selective recovery of lithium from LiCl and LiPFe, using acetonitrile-to-methanol solvent switching to promote uptake and release. In these strategies, receptor-laden organo-gels and polystyrene beads, via direct copolymerization and post- functionalization, respectively, were synthesized. However, these fabrication methods have geometric design constraints, and the resultant materials are either mechanically weak or have low surface area-to- volume ratios and thus poor ion capacity densities. As an alternative, nanoporous inclusions in granular separation systems (i.e., beads) have been used to maximize the surface area-to-volume ratio for capturing a wide range of analytes such as Li, Na, Ca, Co, Ni, Mo, V, and Eu. However, their operation is energy intensive owing to the high pressures required for sufficient fluid flow (i.e., flux). In contrast, nanoporous flat sheet membrane structures can facilitate high flux, but at the price of generally unfavorable surface area-to-volume ratios. Thus, there exists a tradeoff between ion binding capacity per unit volume and fluid flow. Overcoming this dilemma constitutes an all- but-unmet challenge.

[0024] To date, strategies to overcome the capacity-flux paradigm have relied on clever geometric designs across the nano-to-macro-scale continuum. This includes microstructuring (e.g., corrugating), combining multiple flat sheet membranes into a single module (cartridge), and curling hollow-fiber membranes. The apparent importance of multiscale geometric control for high performance ion separations has put 3D printing in the spotlight as an attractive manufacturing tool for this application. In turn, recent studies have emerged where 3D printed scaffolds have been used in gas separations, nuclear wastewater treatment, Au, Pd, Pt, and Co electronic waste recycling, oil extractions from contaminated water, and perchlorate remediation. Despite these impressive advances, the combination of supramolecular receptors, nanoporous materials, and high-resolution 3D printing for separations to date has not been considered in the context of metal ion recognition. It is thus an open question whether such an approach can be used to produce sorbents for critical metal cation capture. As detailed below, the present inventors have now found that digital lightprocessing (DLP) 3D printing can be leveraged as a high resolution, scalable, and low-waste tool to fabricate hierarchical sorbents for cobalt recycling (FIG. 1).

[0025] The present approach relies on polymerization-induced phase separation (PIPS) from a photocurable resin that serves to install nanopores during the DLP printing process. To allow for cobalt capture, a methacrylate functionalized tetradentate bisdicyclohexyl acetamide (BDCA) ligand was synthesized and directly incorporated into the 3D prints. Based upon prior studies using glycolamide-based receptors, such as BDCA, for solvent-polarity dependent binding of lithium, it was postulated that cobalt would also bind with BDCA due to the similarities in coordination preferences between the two ions. Indeed, binding and release of cobalt chloride was demonstrated using ethanol and water as “green” solvents for polarity switching. Furthermore, the influence of nanopore size and microscopic lattice geometry were systematically examined with respect to binding capacity and rate of adsorption, showcasing the utility of structured sorbents in critical material recycling. A significant improvement in 3D printed supramolecular sorbents is therefore provided by the present disclosure.|0026| Accordingly, an aspect of the present disclosure is a porous polymer structure. The porous polymer structure comprises a nanoporous polymer matrix which comprises repeating units derived from a receptor monomer and optionally, a support monomer.

[0027] The support monomer may or may not be present. When present, the support monomer comprises at least one polymerizable group. The polymerizable group is capable of reacting with the reactive species generated from activation of the photoinitiator to provide a polymer. Accordingly, suitable monomer species will depend on the identity of the photoinitiator and the polymerization mechanism enabled by the photoinitiator. The monomer composition can therefore include a free radically polymerizable monomer (e.g., when a radical-generating initiator is used), a cationically polymerizable monomer (e.g., when a photoacid generator is used as the initiator), an anionically polymerizable monomer (e.g., when a photobase generator is used as the initiator), or a combination thereof (e.g., when a combination of photoinitiators are used which are capable of promoting different polymerization mechanisms, for example radical and cationic).

[0028] In an aspect, the polymerizable group comprises a free radically polymerizable monomer having ethylenic unsaturation. Exemplary free radically polymerizable groups can include, but are not limited to, acrylates, methacrylates, acrylamides, methacrylamides, alkenyl aromatics (e.g., styrene and derivatives thereof), vinyl groups (e.g., vinyl acetate), ora combination thereof. In a specific aspect, the polymerizable group comprises an acrylate or a methacrylate. For example, the support monomer can have the structurewherein R is an alkyl group or an alkylene glycol group. For example, in an aspect, R can be a Ci-12 alkyl group, or a Ci-6 alkyl group. In an aspect, R can be an ethylene glycol monomethyl ether group, a triethylene gycol monomethyl ether group, or a tetraethylene glycol monomethyl ether group. Other R groups are contemplated by the present disclosure and can be selected based on the desired polarity of the R group guided by the present disclosure.

[0029] hi an aspect, the support monomer can comprise a crosslinking monomer. That is, the support monomer can comprise at least two polymerizable groups, preferably at least two free radically polymerizable groups comprising ethylenic unsaturation. In some aspects, the support monomer can comprise a mixture of a monofunctional monomer and a crosslinker. In some aspects, the support monomer comprises only a monomer having at least two polymerizable groups. Exemplary free radically polymerizable groups can include, but are not limited to, acrylates, methacrylates, acrylamides, methacrylamides, alkenyl aromatics (e.g., styrene and derivatives thereof), vinyl groups (e.g., vinyl acetate), or a combination thereof. In a specific aspect, the polymerizable group comprises an acrylate or a methacrylate. For example, the support monomer having at least two polymerizable groups can have the structurewherein R’ is an alkylene group or an alkylene glycol group. For example, in an aspect R’ can be a C1-12 alkylene group, or a C2-6 alkylene group. In an aspect R' can be an alkylene glycol group such as a diethylene glycol group, a triethylene glycol group, a tetraethylene glycol group, a dipropylene glycol group, a tripropylene glycol group, a tetrapropylene glycol group, and the like. In a specific aspect, the support monomer can comprise an alkylene glycol diacrylate, for example tripropylene glycol diacrylate. Other monomers having at leasttwo polymerizable groups (e.g., crosslinkers) contemplated by the present disclosure include but are not limited to, vinylic crosslinkers, isocyanate crosslinkers, epoxide crosslinkers, thiol crosslinkers, alkynyl crosslinkers, acrylic acid esters of polyols, methacrylic acid esters of polyols and allyl ethers of polyols each of which has hydroxyl groups substituted with at least two substituents. Examples of the above polyols include ethylene glycol, propylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sucrose, sorbitol and the like. Additional examples of crosslinkers can include divinylbenzene, N,N'-methylenebis(acrylamide), N,N'- ethylenebis(acrylamide), N,N'-propylenebis(acrylamide), N,N'- butamethylenebis(acrylamide), N,N’-diallylacrylamide, N,N'-hexamethylenebisacrylamide, triallylisocyanurate, 1 ,4-diacryloylpiperazine- 1,1, 1 -trimethylolpropane diallyl ether, triethylene glycol divinyl ether, diallyl maleate, bis(acryloylamido)methane, ethyleneglycoldimethacrylate , diethyleneglycoldimethacrylate, 3-(acryloyloxy)-2- hydroxypropyl methacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, diallyl phthalate, triallyl phosphate, allyl methacrylate, tetraallyloxyethane, triallyl cyanurate, divinyl adipate, vinyl crotonate, 1,5-hexadiene, allyl glycidyl ether, and pentaerythritol tetraallyl ether.

[0030] In some aspects, the monomer composition can comprise a monomer comprising an epoxy functional group, an isocyanate functional group, an isothiocyanate group, a carbonate group, an ester group, a vinyl sulfone group, a hydroxyl group, a thiol group, an alkynyl group, or a combination thereof.

[0031] In an aspect, particularly when the photoinitiator comprises a photoacid generator, the monomer composition can comprise a cationically polymerizable group such as a cyclic ether (e.g., an epoxy group, an oxetane group, or the like), a vinyl ether, an oxetane, a spiro-orthocarbonate, a spiro-orthoester, or a combination thereof. In a specific aspect, the cationically polymerizable group can comprise a cycloalkyl ether cationically polymerizable group, preferably an epoxy.

[0032] In an aspect, particularly when the photoinitiator comprises a photobase generator, the monomer composition can comprise a first monomer including at least two hydroxyl groups, at least two thiol groups, or a combination thereof. Non-limiting examples of the first monomer comprising at least two thiol groups can include trimethylolpropane tris(3 -mercaptopropionate); trimethylolpropane tris(2-mercaptoacetate); pentaerythritol tetrakis(2-mercaptoacetate); pentaerythritol tetrakis(3 -mercaptopropionate); ethoxylatedtrimethylolpropane tri (3-mercaptopropionate), 2,2’-(ethylenedioxy)diethanethiol; 3,6-dioxa- 1,8-octane-dithiol; 1,3-propanedithiol; 1,2-ethanedithiol; 1,4-butanedithiol; ; 1,5- pentanedithiol; 1 ,6-hexanedithiol; 1,9-nonanedithiol; xylene dithiol; thiobis(benzenethiol); 1 ,4-butanediol bis(thioglycolate); l,4-bis(3-mercaptobutylyloxy)butane; tris[2-(3- mercaptopropionyloxy)ethyl] isocyanurate; 3,4-ethylenedioxythiophene; 1,10-decanedithiol; tricyclo[5.2.1.02,6]decanedithiol; benzene- 1,2-dithiol; trithiocyanuric acid; 1 -butanethiol; 1- hexanethiol; 1 -heptanethiol; 1 -octanethiol; 1 -nonanethiol; 1 -decanethiol; and 1- octadecanethiol. The monomer composition can further comprise a second monomer including at least two (meth)acrylate groups, at least two (meth) acrylamide groups, at least two vinyl sulfone groups, at least two isothiocyanate groups, at least two isocyanate groups, at least two epoxide groups, at least two carbonate groups, at least two ester groups, at least two alkynyl groups, or a combination thereof. Diisocyanates are specifically mentioned. Non-limiting examples of suitable aliphatic isocyanates include ethylene diisocyanate, trimethylene diisocyanate, 1,6-hexamethylene diisocyanate (HD I), tetramethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 1,6,11 -undecanetriisocyanate, 1,3,6-hexamethylene triisocyanate, bis(isocyanatoethyl)-carbonate, bis(isocyanatoethyl)ether. Other non-limiting examples of suitable aliphatic isocyanates include branched isocyanates such as trimethylhexane diisocyanate, trimethylhexamethylene diisocyanate (TMDI), 2,2'- dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, 2,4,4- trimethylhexamethylene diisocyanate, l ,8-diisocyanato-4-(isocyanatomethyl)octane, 2,5,7- trimethyl-l,8-diisocyanato-5-(isocyanatomethyl) octane, 2-isocyanatopropyl 2,6- diisocyanatohexanoate, lysinediisocyanate methyl ester and lysinetriisocyanate methyl ester. Non-limiting examples of suitable cycloaliphatic isocyanates include dinuclear compounds bridged by an isopropylidene group or an alkylene group of 1 to 3 carbon atoms. Nonlimiting examples of suitable cycloaliphatic isocyanates include l,T-methylene-bis-(4- isocyanatocyclohexane), 4,4'-methylene-bis-(cyclohexyl isocyanate) or 4,4'- dicyclohexylmethane diisocyanate , 4,4’-isopropylidene-bis-(cyclohexyl isocyanate), 1,4- cyclohexyl diisocyanate (CHDI), 3-isocyanato methyl-3,5,5-trimethylcyclohexyl isocyanate (a branched isocyanate also known as isophorone diisocyanate or IPDI). In an aspect, the second monomer can comprise hexamethylene diisocyanate; isophorone diisocyanate; diisocyanatobutane; diisocyanatooctane; 1, 3, 5-tris(6-isocyanatohexyl)- 1,3, 5-triazinane-2, 4,6- trione; phenylene diisocyanate; xylylene diisocyanate; tolyene diisocyanate; cyclohexylenediisocyanate; toluene diisocyanate; methylenebis (phenyl isocyanate); propyl isocyanate; 1- pentyl isocyanate; hexyl isocyanate; octyl isocyanate; nonyl isocyanate; sec -butyl isocyanate; 2-ethylhexyl isocyanate; cyclopentyl isocyanate; and 1 -isocyanato-3 -methylbutane. Use of poly(ethylene glycol) or poly(propylene glycol) diisocyanate terminated polymers are also mentioned (e.g., tolylene 2,4-diisocyanate terminated-poly(propylene glycol) having a number average molecular weight of 1,000 to 5,000 grams per mole). The first and second monomers can be selected to provide a (polyester- sulfide) (e.g., comprising -O(C=O)-L-S- linkages, wherein L is a linking group, for example a Ci-6 alkylene linking group), a poly(amide-sulfide), a poly(sulfone-sulfide), a poly(urethane) (e.g., comprising a - NH(C=O)O- linkage), a poly(thiourethane) (e.g., comprising a -NH(C=O)S- linkage), a poly(dithiourethane) (e.g., comprising a -NH(C=S)S- linkage), a poly(carbonate-sulfide) (e.g., comprising a -O(C=O)O-L-S- linkage, wherein L is a linking group, for example a Ci-6 alkylene linking group), or a poly(ether-sulfide).

[0033] Repeating units derived from the support monomer can be present in an amount of 0 to 99 weight percent, based on the total weight of the polymer network. In an aspect, the polymer structure does not comprise repeating units derived from the support monomer (i.e., repeating units derived from the support monomer are present in an amount of 0 weight percent). In an aspect, when present, repeating units derived from the support monomer can be present in an amount of 1 to 99 weight percent, or 10 to 99 weight percent, or 10 to 90 weight percent, or 20 to 99 weight percent, or 30 to 99 weight percent, or 40 to 99 weight percent, or 50 to 99 weight percent, or 10 to 95 weight percent, or 25 to 95 weight percent, or 50 to 95 weight percent, or 10 to 90 weight percent, or 25 to 90 weight percent, or 50 to 90 weight percent, each based on the total weight of the polymer network.

[0034] In addition to the support monomer (when present), the nanoporous polymer matrix comprises repeating units derived from a receptor monomer. In some aspects, the nanoporous polymer matrix consists of repeating units derived from the receptor monomer. As used herein, the term “receptor monomer” refers to a compound having a polymerizable group and a group capable of bonding with a metal. Preferably, the polymerizable group of the receptor monomer is a free radically polymerizable group comprising ethylenic unsaturation, for example an acrylate, a methacrylate, an acrylamide, a methacrylamide, an alkenyl aromatics, a vinyl group, or a combination thereof. In an aspect, the polymerizable group of the receptor monomer is a (meth) acrylate group. The receptor monomer further comprises at least one receptor group capable of bonding with a metal. Exemplary metalscan include, for example, cobalt, nickel, lithium, manganese, a lanthanide (e.g., a trivalent lanthanide, preferably neodymium ordysprosium), a group 13 element (e.g., a trivalent group 13 element, preferably gallium or indium), or arsenic. Suitable receptor groups can be selected based on the identity of the metal to be bound. Suitable receptor groups can include, but are not limited to, amide groups, calix [4]pyrrole groups, a glycolamide, chelidonic acid, dipicolinic acid, or an Fe(III) hydroxypyridinone.

[0035] In an aspect, the receptor group comprises an amide group, for example a dicyclohexyl amide receptor group. In an aspect, the receptor group capable of bonding with the metal can comprise a bis-cyclohexylamide group, for example wherein the receptor monomer has the structurewherein L is a linking group and PG is a polymerizable group. The polymerizable group PG can comprise a (meth)acrylate), a (meth)acrylamide, an alkenyl aromatic (e.g., styrenic), a vinyl group, and the like. The linking group can be a single bond, a C1-12 alkylene group, an alkylene glycol group, or the like.

[0036] In a specific aspect, the receptor monomer can have the structure

[0037] In an aspect, the receptor group capable of bonding with the metal can comprises a tris-cyclohexylamide group, for example wherein the receptor monomer has the structurewherein L is a linking group and PG is a polymerizable group. The polymerizable group PG can comprise a (meth)acrylate), a (meth)acrylamide, an alkenyl aromatic (e.g., styrenic), a vinyl group, and the like. The linking group can be a single bond, a C1-12 alkylene group, an alkylene glycol group, or the like.

[0038] In a specific aspect, the receptor monomer can have the structureOther variations of the foregoing monomer structures are also contemplated provided that the cyclohexylamide receptor groups are present. For example, other linking groups or polymerizable moieties (e.g., acrylate, (meth)acrylamide), styrenic, vinyl, and the like) arealso possible. In an aspect, the receptor group capable of bonding with a metal comprises a dicyclohexylamide receptor group and the metal comprises cobalt, nickel, or manganese.

[0039] In an aspect, the receptor group capable of bonding with the metal comprises a hemispherand or crown ether- strapped calix [4]pyrrole. For example, a receptor monomer can have the structurewherein L is a linking group and PG is a polymerizable group. The polymerizable group PG can comprise a (meth)acrylate), a (meth)acrylamide, an alkenyl aromatic (e.g., styrenic), a vinyl group, and the like. The linking group can be a single bond, a C1-12 alkylene group, an alkylene glycol group, or the like. In a specific aspect, the receptor monomer can comprise the hemispherand or crown ether-strapped calix[4]pyrrole and the metal can comprise lithium.

[0040] In an aspect, the receptor group capable of bonding with the metal can comprise a glycolamide, chelidonic acid, or dipicolinic acid. For example, the receptor monomer can have the structurewherein in the foregoing structures, PG is a polymerizable group (e.g., a (meth)acrylate), a (meth) acrylamide, an alkenyl aromatic (e.g., styrenic), a vinyl group, and the like), L is alinking group (e.g., a single bond, a C1-12 alkylene group, an alkylene glycol group, or the like), and X is cyclohexyl, phenyl, or an alkyl group such as isopropyl. In a specific aspect, the receptor monomer can comprise the glycolamide, chelidonic acid, or dipicolinic acid and the metal can comprise neodymium or dysprosium.

[0041] In an aspect, the receptor group capable of bonding with the metal can comprise a Fe(III) hydroxypyridinone. For example, the receptor monomer can have the structurewherein in the foregoing structures, PG is a polymerizable group (e.g., a (meth)acrylate), a (meth)acrylamide, an alkenyl aromatic (e.g., styrenic), a vinyl group, and the like), L is a linking group (e.g., a single bond, a C1-12 alkylene group, an alkylene glycol group, or the like). In a specific aspect, the receptor monomer can comprise the Fe(III) hydroxypyridinone and the metal can comprise arsenic.

[0042] The repeating units derived from the support monomer and the receptor monomer can generally be present in any ratio. In an aspect, polymer matrix comprises repeating units derived from the receptor monomer in an amount of 1 to 100 weight percent. In an aspect, the polymer matrix comprises repeating units derived from the receptor monomer in an amount of 100 weight percent (i.e., the polymer matrix consists of repeating units derived from the receptor monomer). In some aspects, the polymer matrix comprises repeating units derived from the receptor monomer in an amount of 1 to 99 weight percent, or 1 to 90 weight percent, or 1 to 75 weight percent, or 1 to 50 weight percent, or 1 to 20 weight percent, or 1 to 10 weight percent, or 10 to 99 weight percent, or 10 to 95 weight percent, or 10 to 75 weight percent, or 10 to 50 weight percent, each based on the total weight of the polymer network.

[0043] The nanoporous polymer matrix derived from polymerization of the support monomer and the receptor monomer comprises a plurality of nanopores having an averagepore diameter of 1 to 1000 nanometers. In an aspect, the plurality of nanopores can have an average pore size of 50 to 500 nanometers, or 80 to 280 nanometers.

[0044] In an aspect, the polymer matrix can have a three-dimensional lattice structure. The lattice structure can comprise a plurality of channels which may be interconnected. The average diameter of the channels is greater than the average diameter of the nanopores. For example, the channels can have an average diameter of 1 micrometer to 10 millimeters. In an aspect, the lattice structure can be a kelvin lattice structure or a gyroid lattice structure.

[0045] The porous polymer structure can advantageously be prepared using an additive manufacturing process, for example a digital light processing (DLP) method. In a 3D printer for a DLP method, a photocurable composition in liquid form can be provided in a vat or spread on a sheet. A predetermined area of the photocurable composition can be exposed to the selected wavelength of light (e.g., UV or visible light having a wavelength selected to activate a photoinitiator). The irradiation with light can be controlled by a digital micro-mirror device or a rotating mirror. In DLP, additional layers are repeatedly or continuously laid and each layer is cured until the desired 3D article is provided.|0046| Accordingly, another aspect of the present disclosure is a method for the manufacture of the porous polymer structure. The method comprises irradiating a resin mixture with light to provide the porous polymer structure. The resin mixture comprises the receptor monomer, a photoinitiator, a porogen, and optionally the support monomer. The support monomer and the receptor monomer can be as described above.

[0047] The photoinitiator is capable of initiating polymerization when irradiated with light, specifically visible or ultraviolet light. In an aspect, the photoinitiator can be a Type I photoinitiator. A Type I photoinitiator refers to a compound that undergoes unimolecular photolysis upon exposure to light. Type I photoinitiators can include photoacid generators, photobase generators, and initiators that form free radicals upon exposure to light. The reactive moiety that is generated by the homolytic cleavage of the photoinitiator will depend on the identity of the photoinitiator.

[0048] Exemplary radical photoinitiators can include, but are not limited to bisacylaphosphine oxides (e.g., phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide), or dialkyl germanium (e.g., bis(4-methoxybenzoyl)diethylgermanium), photoinitiators comprising titanocene derivatives, available under the tradename IRGACURE, available from Ciba Specialty Chemicals, isopropylthioxanthone, benzophenone, 2,2- azobisisobutyronitrile (AIBN), camphorquinone, diphenyltrimethylbenzoylphosphine oxide(TPO), (1 -hydroxy cyclohexylphenylketone) (HCP), bis(2,6-difluoro-3-(l-hydropyrrol-l- yl)phenyl) titanocene, and the like. Also contemplated are compounds of the structurewherein in the foregoing Formulas, X1is boron (B) or gallium (Ga); X2is independently at each occurrence hydrogen, chlorine (Cl), bromine (Br), or iodine (I); Z is carbon or nitrogen; R1is independently at each occurrence a substituted or unsubstituted Ci-6 alkyl group optionally substituted with one or more in-chain or pendent heteroatoms selected from the group consisting of oxygen and sulfur, optionally wherein each occurrence of R1(i.e., on a single X1moiety) can combine to form a cycloalkyl group; R2is a substituted or unsubstituted Ci-6 alkyl group or a substituted or unsubstituted C6-20 aryl group; R3is independently at each occurrence hydrogen, a substituted or unsubstituted C1-6 alkyl group, or a substituted or unsubstituted C6-20 aryl group; R4is independently at each occurrence hydrogen, a substituted or unsubstituted C1-6 alkyl group, or a substituted or unsubstituted C&- 20 aryl group; and Ar is a substituted or unsubstituted fused aryl group optionally substituted with one or more in-chain or pendent heteroatoms selected from the group consisting of oxygen, nitrogen, and sulfur. Such compounds are further described in International Application No. PCT / US2024 / 03 196, the contents of which are hereby incorporated by reference in their entirety.

[0049] In a specific aspect, the photoinitiator comprises a bisacylaphosphine oxide (e.g., phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide).

[0050] In an aspect, the photoinitiator can be a photoacid generator. As used herein, a “photoacid generator” refers to a polymerization initiator that can generate a cationic species when induced by light (e.g., infrared light, visible light, ultraviolet light, far-ultraviolet light, an X-ray, or a charged particle beam, such as an electron beam). Photoacid generators can therefore generate a cationic species in a chemical reaction caused by photoirradiation and initiate cationic polymerization. In an aspect, the photoacid generator may generate a Bronsted acid or a Lewis acid upon irradiation with light. In an aspect, the photoacid generator can be a triarylsulfonium salt, an aryldiazonium salt, a diaryliodonium salt, a dialkylphenacylsulfonium salt, or a sulfonic ester compound. Exemplary photoacidgenerators can include, but are not limited to bis [4- (diphenylsulfonio)phenyl] sulfide bis(hexafluoroantimonate), triphenylsulfonium hexafluoroantimonate, tris(4- methoxyphenyl)sulfonium hexafluorophosphate, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium hexafluorophosphate, 4,4'- bis(diphenylsulfonio)phenyl sulfide-bis-hexafluoroantimonate, 4,4'-bis[di([5- hydroxyethoxy)phenylsulfonio]phenyl sulfide-bis-hexafluoroantimonate, 4,4'-bis[di([3- hydroxyethoxy)phenylsulfonio]phenyl sulfide-bis-hexafluorophosphate, 4- [4'- (benzoyl)phenylthio]phenyl-di-(4-fluorophenyl)sulfonium hexafluoroantimonate, and 4-[4'- (benzoyl)phenylthio]phenyl-di-(4-fluorophenyl)sulfonium hexafluorophosphate. Combinations of photoacid generators can also be used.

[0051] In an aspect, the photoinitiator can be a photobase generator. As used herein, a “photobase generator” refers to a polymerization initiator that can generate an anionic species (e.g., an organic base) when induced by light (e.g., infrared light, visible light, ultraviolet light, far-ultraviolet light, an X-ray, or a charged particle beam, such as an electron beam). Photobase generators can therefore generate an anionic species in a chemical reaction caused by photoirradiation and initiate anionic polymerization. In an aspect, a photobase generator capable of generating an amine upon exposure to light can be used, and include, for example, an ort / zo-nitrobenzyl carbamate compound, an a,a-dimethyl-3,5-dimethoxybenzyl carbamate compound, an acyloxyimino compound and the like.

[0052] Specific examples of the orr / zo-nitrobenzyl carbamate compound include N-(2- nitrobenzyloxy)carbonyl-N-methylamine, N-(2-nitrobenzyloxy)carbonyl-N-n-propylamine, N-(2-nitrobenzyloxy)carbonyl-N-n-hexylamine, N-(2-nitrobenzyloxy)carbonyl-N- cyclohexylamine, N-(2-nitrobenzyloxy)carbonylaniline, N-(2- nitrobenzyloxy)carbonylpiperidine, N,N'-bis[(2-nitrobenzyloxy)carbonyl]-l,6- hexamethylenediamine, N,N'-bis[(2-nitrobenzyloxy)carbonyl]- 1 ,4-phenylenediamine, N,N'- bis[(2-nitrobenzyloxy)carbonyl]-2,4-tolylenediamine, N,N'-bis[(2-nitrobenzyloxy)carbonyl]- 4,4'-diaminodiphenylmethane, N,N'-bis[(2-nitrobenzyloxy)carbonyl]piperazine, N-(2,6- dinitrobenzyloxy)carbonyl-N-methylamine, N-(2,6-dinitrobenzyloxy)carbonyl-N-n- propylamine, N-(2,6-dinitrobenzyloxy)carbonyl-N-n-hexylamine, N-(2,6- dinitrobenzyloxy)carbonyl-N-cyclohexylamine, N-(2,6-dinitrobenzyloxy)carbonylaniline, N- (2,6-dinitrobenzyloxy)carbonylpiperidine, N,N'-bis[(2,6-dinitrobenzyloxy)carbonyl]-l,6- hexamethylenediamine, N,N'-bis[(2,6-dinitrobenzyloxy)carbonyl]-l,4-phenylenediamine, N,N'-bis[(2,6-dinitrobenzyloxy)carbonyl]-2,4-tolylenediamine, N,N'-bis[(2,6-dinitrobenzyloxy )carbonyl]-4,4-diaminodiphenylmethane, N,N'-bis[(2,6- dinitrobenzyloxy)carbonyl]piperazine and the like.

[0053] Specific examples of the a,a-dimethyl-3,5-dimethoxybenzyl carbamate compound include N-(a,a-dimethyl-3,5-dimethoxybenzyloxy)carbonyl-N-methylamine, N- (a,a-dimethyl-3,5-dimethoxybenzyloxy)carbonyl-N-n-propylamine, N-(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl-N-n-hexylamine, N-(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl-N-cyclohexylamine, N-(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbony]aniline, N-(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonylpiperidine, N,N'-bis[(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl]- 1 ,6-hexamethylenediamine, N,N'-bis[(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl]- 1 ,4-phenylenediamine, N,N'-bis[(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl]-2,4-tolylenediamine, N,N'-bis[(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl]-4,4'-diaminodiphenylmethane, N,N'-bis[(a,a-dimethyl-3,5- dimethoxybenzyloxy)carbonyl]piperazine and the like.

[0054] Specific examples of the acyloxyimino compound include acetophenone- O- propanoyl oxime, benzophenone-O-propanoyl oxime, acetone-O-propanoyl oxime, acetophenone-O-butanoyl oxime, benzophenone-O-butanoyl oxime, acetone-O-butanoyl oxime, bis(acetophenone)-O,O'-hexane-l,6-dioyl oxime, bis(benzophenone)-O,O'-hexane- 1,6-dioyl oxime, bis(acetone)-O,O'-hexane-l,6-dioyl oxime, acetophenone-O-acryloyl oxime, benzophenone-O- acryloyl oxime, acetone-O-acryloyl oxime and the like.

[0055] In an aspect, the photobase can be an onium salt, for example as described in co-pending U.S. Patent Application No. 63 / 563,072, filed on March 8, 2024, the contents of which is hereby incorporated by reference in its entirety.

[0056] The concentration of the photoinitiator can be expressed in terms of a molar concentration (i.e., moles per liter (M) of the photocurable composition of millimoles per liter (mM) of the photocurable composition). The photoinitiator can generally be present at any suitable amount or concentration. The photoinitiator can be present in the photocurable composition in a concentration of 0.01 to 500 millimoles per liter of the photocurable composition. Within this range, the photoinitiator can be present in a concentration of at least 0.05 millimoles per liter, or at least 0.1 millimoles per liter, or at least 0.5 millimoles per liter, or at least 1 millimole per liter, or at least 2 millimoles per liter, or at least 5 millimoles per liter of the photocurable composition. Also within this range, the photoinitiator can be present in a concentration of at most 400 millimoles per liter, or at most 300 millimoles perliter, or at most 200 millimoles per liter, or at most 100 millimoles per liter, or at most 50 millimoles per liter, or at most 40 millimoles per liter, or at most 30 millimoles per liter, or at most 25 millimoles per liter, or at most 20 millimoles per liter, or at most 15 millimoles per liter, or at most 10 millimoles per liter of the photocurable composition. For example, in an aspect, the photoinitiator can be present in a concentration of 1 to 10 millimoles per liter, or 4 to 8 millimoles per liter, or 5 to 15 millimoles per liter. Though the aforementioned concentrations may be preferred, other concentrations are also contemplated by the present disclosure. For example, the photoinitiator can be present in a concentration of at least 0.01 millimoles per liter, at least 0.05 millimoles per liter, or at least 0.1 millimoles per liter, or at least 0.5 millimoles per liter, or at least 1 millimole per liter, or at least 10 millimoles per liter, or at least 100 millimoles per liter, or at least 500 millimoles per liter, or at least 1 mole per liter, or at least 5 moles per liter. In an aspect, the photoinitiator can be present in a concentration of no more than 10 moles per liter, or no more than 5 moles per liter, or no more than 1 mole per liter, or no more than 500 millimoles per liter, or no more than 100 millimoles per liter, or no more than 50 millimoles per liter, or no more than 10 millimoles per liter, or no more than 1 millimoles per liter, or no more than 0.5 millimoles per liter, or no more than 0.1 millimoles per liter.

[0057] In addition to the support monomer (when present), the receptor monomer, and the photoinitiator, the resin mixture further comprises a porogen. A porogen refers to a compound that can be moved from the polymer matrix (e.g., during or after manufacture). Removal of the porogen leaves pores in the polymer structure and can be by, for example, diffusion, dissolution, degradation, volatilization, or a combination thereof. The porogen is preferably a liquid (e.g., at room temperature (25 °C)), for example an organic solvent. Preferably, the receptor monomer has a greater solubility in the porogen than the support monomer to provide increased surface exposure of the receptor moiety. Suitable porogens will also be initially miscible with the resin mixture, but phase separate upon polymerization (e.g., the porogen will phase separate from the polymer). Stated another way, the porogen is a relatively poor solvent for the polymer, leading to phase separation and thus the formation of the pores. Thus, the polymer derived from the receptor monomer and optionally the support monomer has a solubility in the porogen that is less than a solubility of the support monomer (when present) and the receptor monomer. In an aspect the porogen can be a high boiling point liquid. Accordingly, suitable porogens will be selected based on the identity of the receptor and support monomers, as will be recognized by a person having skill in the artguided by the present disclosure. The porogen can generally be any solvent or liquid that is capable of providing the necessary phase separation upon polymerization to provide the desired porous structure. It will be understood that not all of the porogens described hereinafter are equally effective in providing pores in polymer structures of all compositions. Rather, one of ordinary skill in the art can readily select the best porogen for a specific polymer guided by the present disclosure.

[0058] Exemplary porogens can include, but are not limited to alkanol porogens, for example a monoalcohol (e.g., a compound having a single hydroxyl group. Exemplary monoalcohols can be C1-12 alkyl monoalcohols. Suitable monoalcohols can include, but are not limited to, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, cyclohexanol, 1 -decanol, ,and the like, or a combination thereof. In some aspects, alkyl acetates (e.g., dodecyl acetate) may be used. Other porogens can include polar organic solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, tetrahydrofuran, acetone, N-methylpyrrolidone, and acetonitrile. In an aspect, the porogen can comprise an alkylene glycol or a polymer thereof, for example polyethylene glycol or polypropylene glycol, preferably having a hydroxyl end group. The weight average molecular weight of polyethylene glycol and polypropylene glycol can be 10,000 grams per mole (g / mol) or less, or 8,000 g / mol or less, or 6,000 g / mol or less, or 4,000 g / mol or less, or 1 ,000 g / mol or less, or 800 g / mol or less, or 600 g / mol or less, or 400 g / mol or less. Other suitable porogens can include aliphatic water soluble compounds having at least 3 hydroxyl groups. Typical porogens can include monosaccharides, disaccharides, and polysaccharides such as glucose, ribose, sucrose, maltose, lactose, maltotriose, and dextran, such as monosaccharides such as gluconic acid, mannitol, glucuronic acid, and glucosamine. Derivatives and polyols such as, for example, glycerol, trimethylolpropane, pentaerythritol can also be used. Aromatic solvents are also contemplated for use as porogens, for example, benzene, toluene, and substituted derivatives thereof. Aliphatic hydrocarbons are also contemplated, for example Ce- o alkanes (e.g., hexane, cyclohexane, cyclooctane, decane, dodecane, and the like).

[0059] In a specific aspect, the porogen can comprise cyclohexanol, 1 -decanol, or a combination thereof. In an aspect, the porogen can comprise cyclohexanol and 1 -decanol in a weight ratio of cylohexanol: I -decanol of 100:0 to 0: 100, or 90:10 to 10:90, or 80:20 to 20:80, or 70:30 to 30:70, or 60:40 to 40:60.

[0060] The porogen can be present in an amount of 1 to 90 weight percent, based on the total weight of the resin mixture. Within this range, the porogen can be present in an amount of at least 5 weight percent, or at least 10 weight percent, or at least 15 weight percent, or at least 20 weight percent, or at least 25 weight percent, or at least 30 weight percent, or at least 35 weight percent, or at least 40 weight percent, or at least 45 weight percent, each based on the total weight of the resin mixture. Also within this range, the porogen can be present in an amount of at most 85 weight percent, or at most 80 weight percent, or at most 75 weight percent, or at most 70 weight percent, or at most 65 weight percent, or at most 60 weight percent, or at most 55 weight percent, or at most 50 weight percent, or at most 45 weight percent, or at most 40 weight percent, or at most 35 weight percent, or at most 30 weight percent, or at most 25 weight percent, or at most 20 weight percent, or at most 15 weight percent, or at most 10 weight percent. As shown in the working examples, the amount of porogen can affect resulting pore size of the final porous polymer structure.

[0061] The resin mixture is liquid at room temperature (e.g., at 25°C). In an aspect, one or both of the support monomer and the receptor monomer are liquids at room temperature and are capable of dissolving the other components of the resin mixture. In an aspect, the resin mixture can optionally further comprise a suitable solvent. When present, the solvent is selected to sufficiently dissolve or disperse the components of the resin mixture. Suitable solvents can be selected based on the selected components and guided by the present disclosure. Exemplary solvents can include but are not limited to tetrahydrofuran, dimethylformamide, N-methylformamide, formamide, acetonitrile, dimethylacetamide, dimethylacetamide, propylene carbonate, ethylene carbonate, N-methylpyrrolidone, dimethylsulfoxide, and combinations thereof. In an aspect, the resin mixture does not include a solvent.

[0062] In an aspect, the resin mixture can optionally further comprise an additive, provided that the presence of the additive does not significantly adversely affect one or more desired properties of the resin mixture, the light-based method of curing, or the final cured composition. When present, additive(s) can be mixed with the resin mixture at any suitable time during the mixing of the components for forming the composition. In an aspect, the resin mixture can include a fdler (e.g., glass, carbon, mineral, or metal) or reinforcing agent. Additives can be used in amounts generally known to be effective. In an aspect, the resin mixture can optionally include a viscosity modifier selected to adjust the viscosity of themixture to a desired range. In an aspect, the resin mixture can include an oxygen scavenger. When present, the oxygen scavenger can comprise a phosphine, a thiol, an alkene, or a combination thereof. Exemplary oxygen scavengers can include, but are not limited to, hydrogen donors (e.g., thiols, amine, hydrogen phosphites, silanes, stannanes, benzaldehydes); n-vinyl amides; reducing agents (e.g., phosphines, phosphites, sulphites, borane-amine complexes); singlet oxygen scavengers (e.g., diphenyl furans, anthracenes); and combinations thereof. When included in the resin mixture, an oxygen scavenger can be present in a concentration of 1 to 100 millimoles per liter of the resin mixture. Other concentrations are also contemplated by the present disclosure. For example, an oxygen scavenger can be present in a concentration of at least 0.1 millimoles per liter, or at least 0.5 millimoles per liter, or at least 1 millimole per liter, or at least 10 millimoles per liter, or at least 100 millimoles per liter, or at least 500 millimoles per liter, or at least 1 mole per liter, or at least 5 moles per liter. In an aspect, the oxygen scavenger can be present in a concentration of no more than 10 moles per liter, or no more than 5 moles per liter, or no more than 1 mole per liter, or no more than 500 millimoles per liter, or no more than 100 millimoles per liter, or no more than 50 millimoles per liter, or no more than 10 millimoles per liter, or no more than 1 millimoles per liter, or no more than 0.5 millimoles per liter, or no more than 0.1 millimoles per liter. In some aspects, an additional oxygen scavenger is omitted or excluded from the resin mixture.

[0063] The method comprises irradiating the resin mixture with light. In an aspect, irradiating the resin mixture can be with light having a wavelength of 400 to 1000 nanometers, for example 400 to 800 nanometers, or 450 to 750 nanometers. Any suitable light intensity can be used. In an aspect, the light can have an intensity of less than 10 mW / cm2. In an aspect, the light intensity can be 0.1 to less than 10 mW / cm2, or 0.5 to less than 10 mW / cm2, or 1 to less than 10 mW / cm2, or 2 to 8 mW / cm2, or 3 to 7 mW / cm2, or 4 to 6 mW / cm2, or 1 to 8 mW / cm2, or 1 to 7 mW / cm2, or 1 to 6 mW / cm2, or 1 to 5 mW / cm2, or 0.5 to 8 mW / cm2, or 0.5 to 7 mW / cm2, or 0.5 to 6 mW / cm2, or 0.5 to 5 mW / cm2, or 0.1 to 8 mW / cm2, or 0.1 to 7 mW / cm2, or 0.1 to 6 mW / cm2, or 0.1 to 5 mW / cm2. Combinations of any of the above are also possible in certain aspects. In an aspect, the light source can be a light emitting diode.

[0064] The temperature of the reaction is not particularly limited as long as the reaction proceeds. For example, the method can be conducted at a temperature of 0 to 100 °C, for example 10 to 60 °C, or 20 to 40 °C. The gelation time of the photocurablecomposition can be 60 seconds or less, or 1 to 30 seconds, or 1 to 15 seconds. Such timescales (e.g., 15 seconds or less) can be particularly useful for applications of the disclosed method to lithography or 3D printing (additive manufacturing). Thus in some aspects, the method can be a three dimensional printing method, preferably a light-based additive manufacturing method, more preferably digital light processing, stereolithography, or computed axial lithography.

[0065] In an aspect, the method can be a light-based additive manufacturing method (e.g., a digital light processing method) wherein the method comprises irradiating a first portion of the resin mixture with light to induce polymerization and form a first layer on a substrate. The light can be provided by a light source comprising a light emitting diode. The light source can be an incoherent light source. The method further comprises forming at least one additional layer on the first layer by irradiating a second portion of the resin mixture to induce polymerization to form the additional layer. The method steps of irradiating and forming the layers can be repeated until a desired number of layers are formed to provide the three-dimensional structure. In an aspect, each layer can comprise a crosslinked polymer matrix derived from the support and receptor monomers. In an aspect, adjacent layers may be chemically bonded at an interface between the layers. In an aspect, the method can have a print rate of 60 second / layer or less, or 30 seconds / layer or less, 15 seconds / layer or less, or 10 seconds / layer or less. In an aspect, the method can have a print rate of 1 millisecond / layer or more, for example 50 milliseconds / layer or more, 1 second / layer or more, 5 seconds / layer or more, 10 seconds / layer or more, 15 seconds / layer or more, 20 seconds / layer or more, or 25 seconds / layer or more. The print rate can range from any of the minimum values described above to any of the maximum values described above. For example, the method can have a print rate of from 1 millisecond / layer to 30 seconds / layer, or from 1 millisecond / layer to 25 seconds / layer, from 1 millisecond / layer to 20 seconds / layer, from 1 millisecond / layer to 15 seconds / layer, from 1 millisecond / layer to 10 seconds / layer, or from 1 millisecond / layer to 5 seconds / layer.

[0066] The method can further comprise removing the porogen from the polymer structure. In an aspect removing the porogen can comprise volatilizing the porogen, for example at reduced pressure and optionally, heat. In an aspect, removing the porogen can be by critical point drying, which is believed to mitigate collapse of the pores. Critical point drying is a technique that avoids effects of surface tension on the liquid / gas interface by substantially preventing a liquid / gas interface from developing. Critical point orsupercritical drying does not cross any phase boundary, instead passing through the supercritical region, where the distinction between gas and liquid ceases to apply. As a result, materials dehydrated using critical point drying are not exposed to surface tension forces, which can damage the pore structure. When the critical point of the liquid is reached, it is possible to pass from liquid to gas without abrupt change in state.

[0067] The porous polymer structures according to the present disclosure can be particularly useful for capture (and release) of a target metal species. A method of binding a target metal species therefore represents another aspect of the present disclosure. The method comprises contacting a fluid mixture with the porous polymer structure of the present disclosure, wherein the fluid mixture comprises a target metal species. The target metal species can comprise, for example, cobalt, nickel, lithium, manganese, neodymium, dysprosium, gallium, indium, or arsenic.

[0068] The contacting is preferably conducted in the presence of a solvent. Stated another way, the fluid mixture can comprise the target metal species in a solvent. The solvent during the contacting (i.e., the solvent of the fluid mixture) is selected such that the binding efficiency of the target metal species to the receptor of the porous polymer structure is increased. In an aspect, the contacting can be in the presence of an alcoholic solvent, for example ethanol or isopropanol.

[0069] The method can further comprise releasing bound (or captured) target metal species by contacting the porous polymer structure comprising the captured target metal species with a solvent that decreases the binding efficiency of the target metal species to the receptor. Preferably the solvent for release of the target metal species has a polarity that is higher than the solvent used for capture of the target metal species. In an aspect, the solvent for release of the target metal species can comprise water.

[0070] In an aspect, the fluid mixture comprising the target metal species can be a stream derived from electronic waste. In an aspect, the fluid mixture can be a leachate from a magnet (e.g., a NdFeB magnet). In an aspect, the fluid mixture can be a leachate from a battery (e.g., comprising, Li, Co, Ni, Mn, or a combination thereof). In an aspect, the fluid mixture may comprise more than one target metal species (e.g., Li and Co or Nd, Dy, and Co) and accordingly the contacting can be with a porous polymer structure comprising more than one type of receptor group or with multiple porous polymer structures, each comprising a receptor group specific to a particular target metal species. The contacting with multiple porous polymer structures can be in series, and each porous polymer structure can beprovided in a cartridge. In some aspects, particularly when other metal species may be present (e.g., Fe), the fluid mixture can first be subjected to other purification means such as precipitation to remove metals or other components that may otherwise interfere with the adsorption of the target metal species. Once metal ion concentrations in the fluid mixture are sufficiently low (which can be determined by in situ monitoring), the solvent polarity (and / or pH) can be switched to induce release of the captured metals. Subsequent precipitation and isolation by filtration can provide the desired recycled metal species with high purity (e.g., greater than 99%), which are suitable for reuse in the manufacture of new devices (e.g., batteries, magnets, etc.).

[0071] A system for removing a target metal species from a fluid mixture represents another aspect of the present disclosure. The system can comprise a feed vessel comprising a fluid mixture comprising the target metal species. As noted above, the fluid mixture can be a leachate obtained from electronic or magnetic waste. The feed vessel is in fluid communication with a high pressure pump capable of conveying the fluid mixture to a cartridge comprising the porous polymer structure of the present disclosure, wherein the porous polymer structure is capable of binding a target metal species. Optionally, more than one cartridge may be fluidly connected in series, wherein each cartridge comprises a porous polymer structure capable of binding a different target metal species. The outlet of the cartridge is fluidly connected to the feed vessel, such that the mixture can be circulated in a closed loop until a desired concentration of metal species in the fluid mixture is obtained. The system can optionally comprise an in situ monitoring system for analyzing the concentration of the metal species in the fluid mixture over time. An exemplary system is shown in FIG. 15, where a system and process of purifying a fluid mixture derived from a leachate of a NdFeB magnet is schematically illustrated.

[0072] This disclosure is further illustrated by the following examples, which are nonlimiting.EXAMPLESReceptor Synthesis

[0073] The porous sorbents described herein were prepared from a resin mixture containing a support monomer, receptor comonomer, and porogens (FIG. 2). A copolymerization approach was chosen to install the receptor in one-step, ensuring incorporation with precise control over content via feed ratios, while mitigating the presenceof unreacted functional groups that would occur if using a post-polymerization strategy. The BDCA receptor was selected for Co2+recycling given its precedent to bind and release LiPFe with high selectivity in acetonitrile, along with the affinity of glycolamides for transition metals. To start, a polymerizable methacrylate handle was installed on the BDCA receptor to enable copolymerization with commercially available acrylate monomers commonly employed as resins for 3D printing. This was accomplished by reacting / <? / 7-buloxycarbonyl (BOC) protected 2-aminopropane-l,3-diol with 2-bromo-A, A-dicyclohexylacetamide in the presence of sodium hydride to generate the corresponding BOC-protected BDCA. Subsequent BOC deprotection with trifluoroacetic acid followed immediately by amide formation with methacryloyloxyethyl succinate (MA-OSu) provided the desired BDCA- methacrylate (BDCA-MA) monomer. Copolymerization between BDCA-MA and carbitol acrylate (model monomer) initiated by phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) upon exposure to 405 nm light provided good receptor incorporation as desired. This proved true even though NMR spectroscopic analyses revealed that BDCA-MA reacted slightly faster than the carbitol acrylate.Polymerization-Induced Phase Separation (PIPS)

[0074] Using tripropyl-ene glycol diacrylate (TPGDA) as the support material, 1- decanol (dec) and cyclohexanol (eye) as porogens, and BAPO as the photoinitiator, PIPS was evaluated for a range of monomer to porogen ratios, as well as the 1 -decanol to cyclohexanol ratios. Exemplary resin formulations are shown in Table 1.Table 1

[0075] To correlate composition to phase separation, films were cast between glass slides with 75 pm spacers, irradiated with a 405 nm LED (5.0 mW / cm2) for 120 seconds, washed with acetone to remove porogens and residual monomer, and dried in a vacuum oven overnight. The transmittance of each film was then measured and used to construct a ternaryphase separation diagram using poly(TPGDA) prepared without porogens as a baseline (FIG. 3). A reduction in transmittance was taken as an indication of phase separation due to Rayleigh scattering arising from nanoscale features. Therefore, transmittance below -unity was deemed as evidence for effective PIPS. On this basis, it was concluded that resins containing 50 wt% TPGDA relative to porogen resulted in phase separation, while higher TPGDA contents (lower porogen concentrations) did not phase separate (FIG. 3). Qualitatively, varying the cyclohexanol to 1 -decanol ratios while maintaining a constant TPGDA content of 50 wt% provided good control over the extent of PIPS, as indicated by a decrease in transmittance (increase in opacity) as the ratio decreased (i.e., more 1 -decanol; FIG. 3, images). Thus, going forward 50 wt% porogen relative to TPGDA was used. The same samples were prepared using critical point drying (CPD) instead of vacuum oven drying to mitigate pore collapse. Scanning electron microscopy (SEM) was performed to determine pore sizes following a previously reported image analysis protocol. This analysis revealed pore diameters of 100 ± 10, 122 ± 2, 115 + 1, 168 + 2, and 270 ± 30 nanometers (nm) for cyclohexanol to 1 -decanol ratios of 1 :0, 4: 1, 1:1, 1 :4, and 0:1, respectively (FIG. 4). These results served to corroborate the qualitative observation of opacity, where increasing the amount of 1 -decanol relative to cyclohexanol was found to produce larger phase separated domains and bigger pores upon removal of the porogens.

[0076] The incorporation of BDCA-MA into the polymer network using this method was next confirmed using elemental analysis and attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy. By increasing the receptor feed from 0 to 5 mol% relative to TPGDA, the resultant polymers were found to contain nitrogen contents of 0.113 ± 0.006% to 0.57 ± 0.02%, respectively, as shown in Table 2. Table 2

[0077] These findings correlate well with the theoretical loading levels (nitrogen content = 0.13 and 0.60%, respectively), and were thus taken as evidence that receptor loading had been successfully achieved. ATR-FTIR spectroscopy of the polymers further confirmed the incorporation of BDCA-MA as inferred from the presence of secondary amine and amide signatures at 3270 cm'1(N-H stretching) and 1639 cm'1(C=O stretching), respectively. On this basis, it was concluded that light-driven PIPS from resins containingBDCA-MA constitutes a viable strategy for the preparation of materials with tunable pore size and receptor content.Digital Light Processing (DLP) 3D Printing

[0078] Polymeric objects were prepared using digital light processing (DLP) 3D printing, which is a layer-by-layer stereolithography technique that provides an attractive combination of build speed, feature resolution, and isotropic mechanical properties. All objects were produced using the following print settings: Bottom-up LED exposure with a central wavelength of 405 nm, intensity of 8.6 mW / cm2, and 1 second irradiation time per 25 pm layer (FIG. 5). Printed objects were soaked in ethanol to remove residual resin components. The structures could be used directly for ion sorption experiments (i.e., without drying); however, CPD was employed to characterize structure and enable the gravimetric analyses used to quantify ion capacity (vide infra). The accessible surface areas of dried samples prepared as printed cylinders (3 mm x 22 mm) were estimated using the Brunauer- Emmett-Teller (BET) approach with N2 as the probe gas. These studies revealed a general trend of increasing surface area from 20.3 ±0.3 to 45.4 ±0.3 m2 / g as the pore size decreased from 270 ±30 nm to 122 ±2 nm for samples prepared from resins containing cyclohexanol to 1 -decanol ratios of 0:1 and 4:1, respectively. Surface areas, densities, and porosities for different porogen compositions based on nitrogen adsorption isotherms are summarized in Table 3.Table 3

[0079] Notably, the samples with the smallest pores (-100 nm as measured on the films using SEM), had a lower measured surface area relative to those having the next smallest pores (-120 nm). This finding is attributed to the presence of phase mixed regions or isolated pores. Finally, density measurements of 3D printed cubes revealed porosity values that increased from 24 ± 2 to 50.6 ± 0.9 % upon increasing the pore size from -100 to 300 nm (Table 3). To test whether the present additive manufacturing approach would allow access to complex microarchitectures, three structures were produced all having 10 mm x 10mm x 10 mm outer dimensions, namely cube, kelvin lattice, and gyroid (FIG. 6). Such geometric control has the potential to enable production of mechanically robust sorbents with improved longevity and reuse, along with the ability to maximize capacity and flux. The structures were produced with high feature fidelity, as demonstrated by hole diameters of -500 pm in the kelvin lattice and wall thicknesses of -375 pm in the gyroids. This printing process thus provided hierarchical structures that span the nanometer to millimeter length scales as determined from SEM imaging that revealed nanoporous voids, micrometer-steps analogous to those in corrugated membranes, and millimeter lattices (FIG. 6). The influence of pore size on the mechanical integrity was also examined by carrying out uniaxial compression tests on 5 mm x 5 mm x 5 mm nanoporous cubes. These studies revealed elastic moduli (E) ranging from 410 ± 60 to 72 ± 8 MPa for 100% cyclohexanol (-100 nm pores) to 100% 1-decanol (-300 nm pores), respectively (FIG. 6). Thus, it was concluded that the stiffness of the present printed structures could be tuned by controlling porosity. This ability, in turn, provides a mechanism to design sorbents appropriate to meet the demands of a particular separations process involving, e.g., specific fluid pressures.Cobalt (II) Chloride Binding

[0080] A diffraction grade BDC A-NiCF crystal was obtained via vapor diffusion from diethyl ether into an ethyl acetate solution containing BDCA-NiCF and served as a proxy. The resulting cluster-like structure revealed the presence of octahedral complexes, chloride-bridged bimetallic complexes, and a tetrachlorometallate. In solution, these coordination complexes can exist in equilibrium with multiple species. This complexity precluded the attainment of reliable binding constants for the free receptors. However, for the case of im-mobilized receptors, the relative affinities could be inferred from Freundlich constant and exponents.

[0081] The Co2+binding profiles of 3D printed sorbents were measured in so-called “green” solvents, namely ethanol (EtOH), isopropyl alcohol (IPA), and water (H2O), to determine the most selective analyte binding and release environments. Kelvin lattices (10 mm x 10 mm x 10 mm) containing 5 mol% BDC A receptor and -120 nm pores (from cyclohexanol: 1-decanol 1 : 1) were placed in a container with a defined concentration (~mM) of cobalt chloride (C0CI2) or lithium chloride (LiCl) (FIG. 7). After allowing to stand for 12 hours to reach equilibrium, the 3D printed structures were removed, the initial solvents were exchanged for water, and the conductivity values measured to determine ion concentrationsby comparison to calibration curves. The experimental binding profiles were fit to non-linear Freundlich isotherms with R2values exceeding 0.95. In these models, correction factors (n) provide insights into the ion binding interactions. Specifically, when n’1is <1 binding is favorable, while n1>1 indicates unfavorable binding. For C0CI2, strong binding in IPA and EtOH was observed, with n values of 2.80 and 2.27, respectively (FIG. 8). Conversely, weak binding of C0CI2 in H2O was observed, with an n value of 0.99. This difference allowed EtOH or IPA to be used as solvents for effective C0CI2 binding, whereas treatment with H2O could be used to effect Co2+release. Ultimately, it is believed that this solvent polarity switching in combination with appropriately 3D-printed receptor-containing materials could be used for cobalt recycling.

[0082] The BDCA ligand also has affinity for lithium salts. Given this propensity, and the presence of Li+in acid leachate from lithium-ion batteries (along with Co2+), Li+binding capabilities of the present BDCA-MA based 3D printed sorbents was also examined. These studies were further motivated by an appreciation of the difficulty in selectively separating these two ions (Co2+vs Li+) using contemporary strategies. The adsorption isotherms of LiCl in IPA and EtOH provided n values of 1.74 and 1.13, respectively, which were both lower than those for C0CI2 (FIG. 8).

[0083] The affinity of the BDCA ligand for manganese- and nickel-salts was also examined given their increasing presence in lithium-ion battery cathodes. The Freundlich isotherms revealed that BDCA had a moderately higher affinity for C0CI2 over NiCh in EtOH (n = 2.27 vs. 2.07), while a much lower affinity for MnCF in EtOH was observed (n = 1.14). These results lead us to suggest that the 3D printed sorbents can provide selectivity for Co2+over Li+and Mn2+in alcohol solvents. Based on the relatively large difference in binding affinity in EtOH, along with its reduced toxicity compared to IPA, further experiments were performed using EtOH as the solvent.

[0084] Next, the fundamental binding kinetics and capacities of the structured sorbents as a function of nanoporosity and microstructure were examined using the kelvin lattice. The blue appearance of tetrahedral cobalt complexes provides a distinct visual queue for adsorption and provides a colorimetric sensor for qualitatively assessing the extent of BDCA-C0CI2 complex formation (FIG. 9). The colored sorbent was characterized using SEM and energy dispersive X-ray (EDX) spectroscopy to determine the elemental composition. Mapping of cobalt and chlorine showed a similar homogenous spatial distribution andprovided a ratio of ~1 :2 for Co:Cl. This elemental ratio is taken as evidence that the bound cobalt is in the 2+ oxidation state.

[0085] The influence of nanopore size on the rate of cobalt uptake was also determined. It was hypothesized that increasing the pore size would lead to an increase in the rate of diffusive transport, and therefore uptake. To test this conjecture, kelvin lattices with pore sizes ranging from ~100 nm (cyclohexanol only) to ~300 nm (1 -decanol only) were prepared with 5 mol% BDCA, along with nonporous controls (Table 1). The rate of uptake was tracked hy monitoring the change in absorption at 659 nm (tetrahedral cobalt complex) of the EtOH solution containing the printed object as a function of time. Changes in the C0CI2 concentration were determined from a calibration curve. On this basis, it was confirmed that the rate of uptake increased with pore size as predicted (FIG. 10). Specifically, samples with the largest pores (-300 nm) exhibited a pseudo-first order rate constant ( ri ) of 8 ± 1 xlO-2min1. Conversely, the samples containing the smallest pores (-100 nm) displayed a k of 4 ± 2 xlO-2min1. This finding provides support for the suggestion that the C0CI2 uptake in these samples is diffusion limited.|0086| The influence of receptor loading on C0CI2 equilibrium capacity was then examined for kelvin lattices containing nanopores of intermediate size (-120 nm, from a 1 : 1 mixture of cyclohexanol: 1 -decanol). For these studies, samples were soaked in 25 mM C0CI2 solutions (EtOH) and aliquots were removed after 48 hours and the total uptake determined spectroscopically. Increasing the BDCA receptor loading from 0 to 5 mol% led to a corresponding increase in uptake, as noted by the visual increase in blue color (FIG. 11). Specifically, for 0, 1, 2.5, and 5 mol% BDCA-MA uptake values of -0.7 ± 0.9, 3.5 + 0.8, 9.5 + 0.4, and 12 + 2 mg-g’1were recorded, respectively. These uptake values correspond to 80 + 20%, 89 ± 5%, and 60 ± 8% of the theoretical maximum binding capacity. Analogous studies involving samples with the smallest nanopores (-100 nm) and 2.5 mol% BDCA-MA produced an uptake value of 5 + 1 mg-g’1, which corresponds to a 50 + 10% binding capacity (FIG. 11). As expected, increasing the nanopore size to -300 nm while maintaining 2.5 mol% BDCA led to nearly 100% binding (FIG. 11).

[0087] Finally, the influence of microstructure on the C0CI2 capacity and rate of uptake was examined (FIG. 12). Samples with cube, kelvin lattice, and gyroid geometries having nanopores of intermediate size (-120 nm, from a 1 :1 mixture of cyclohexanol and 1- decanol) along with a nonporous cube control were tested following the same soaking and UV-vis absorption spectroscopy protocols used above. Geometries with larger surface-area-to- volume ratios (gyroid > kelvin lattice > cube > nonporous kelvin lattice > nonporous cube) were found to result in higher capacity and faster uptake rates (FIG. 12). Specifically, uptake values of 94 + 7%, 91 + 4%, 75 + 3%, 32 + 8%, and 5 + 1% relative to the theoretical maximum capacity were measured for the gyroid, kelvin lattice, cube, and nonporous cube, respectively. These results demonstrate that the surface area-to-volume ratio influences the binding properties. Thus, performance can be related directly to both the nano- and microscale geometries that, in turn, are readily controllable via the present 3D printing approach.

[0088] To extend the present platform to real world critical material recycling requires both the ability to bind (“catch”) and release the desired ion, and to do so reproducibly over many cycles. This capability was tested via “green” solvent cycling between EtOH and H2O with a 5 mol% BDC A-containing kelvin lattice having ~ 120 nm pores (prepared from a 1 : 1 cyclohexanol to 1-decanol porogen mixture) (FIG. 13). Samples were placed into a stock solution of C0CI2 in EtOH (18.76 mM), allowed to bind for 12 h, and then removed. The conductivity of the stock solution was measured to determine the amount of bound C0CI2 relative to a calibration curve. This revealed a 78 ± 2% binding capacity, which was comparable to that obtained using UV-vis absorption spectroscopy on an analogous sample (5 mol% BDCA, 120 nm pores, kelvin lattice) after a 48-hour soak to allow equilibrium to be reached (60 + 8% binding). Subsequently, the Co-laden sorbent was placed in pure H2O for 12 hours and the conductivity was measured to assess the amount of released C0CI2 based on a calibration curve. Notably, 90 + 1% of the bound C0CI2 was released after the first cycle, which was further supported by a visual loss in sorbent color (i.e., blue to white) (FIG. 13). The release of C0CI2 is attributed to an increase ion-solvent interaction strength that follows the spectrochemical series for increasing polarity in going from ethanol to water. Repeating this process with the regenerated sorbent over a total of 5 cycles revealed no statistically significant change in binding or release capacity. Additionally, no change to the morphology or elastic moduli of representative samples post cycling was observed. On this basis it was concluded that the present system provides for good reproducibility when subject to repeated use.

[0089] LiCoO2 is currently the most common cathode material in portable batteries. Recycling of these batteries includes an early-stage acid (e.g., HC1) leaching step. This produces a mixture of Co2+and Li+from which it is notoriously difficult to separate out the individual ions. Thus the selectivity of the present sorbents for Co2+over Li+was determined. With this goal in mind, a simulated leachate solution containing LiCl and C0CI2 in EtOH (2mL) was prepared and placed three distinct 5 mol% BDCA-containing 3D printed kelvin lattices (230 mg sample, -120 nm pores) in the mixed ion solution (FIG. 14). Inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed an initial concentration of 27.0 mM and 21.1 mM for Li+and Co2+, respectively. After soaking the sorbents in the solution for 12 hours, the now blue samples were removed, rinsed with EtOH, and then placed in pure H2O (2 mL) for 12 hours to release the bound ions. At the end of this procedure, the initial ethanol phase was found to contain a considerably higher ratio of Li+to Co2+with concentrations of 20.7 + 0.4 mM and 7.9 ± 0.9 mM being recorded for Li+and Co2+, respectively (FIG. 14). Conversely, the final aqueous phase was found to contain 2.6 ± 0.2 mM of Li+and 11.2 ± 0. 1 mM of Co2+. This corresponds to a 5.6x reduction in the Li+to Co2+ratio, from 1.28 to 0.23. The selectivity of the 3D printed support for Co2+over Li+corresponds to the binding isotherms in ethanol previously determined and is taken as evidence that the BDCA-containing 3D printed kelvin lattices bind Co2+more strongly than Li+. More broadly, these findings suggest that 3D printed nanoporous polymer sorbents, such as those described here, may enable effective lithium-ion battery recycling with minimal secondary waste generation.

[0090] Thus, digital light processing allowed the 3D printing of objects with defined microstructures. The present results demonstrate the potential of this platform in the context of cobalt recycling from spent lithium-ion batteries. Given its modularity, low cost, and minimal waste generation, the present strategy can be generalized to allow for the beneficiation and recycling of critical materials. A significant improvement is therefore provided by the present disclosure.

[0091] Experimental details follow.

[0092] Materials: All reagents were used as received unless otherwise noted. Cobalt(II) chloride 97% (anhydrous), cyclohexanol 99%, and phenylbis(2,4,6- trimethylbenzoyl)phosphine oxide (BAPO) 97%, were purchased from Sigma-Aldrich. Tripropylene glycol diacrylate >90.0% (TPGDA) and 2-[2-(2-methoxyethoxy)ethoxy]-ethyl acrylate >95% (both stabilized with hydroquinone monomethyl ether (MEHQ)) were purchased from TCI. Note that monomers and cross-linkers were not purified prior to use, and as such any inhibitor present (e.g., phenolics) from the commercial source remained. 1- Decanol 99% was purchased from Acros Organics. Ethyl alcohol (ACS reagent grade, anhydrous) for synthesis was purchased from RICCA Chemical Company. Ethanol 200 proof was purchased from Decon Laboratories. CDCE (D 99.8%) and G e iD 99.5%) werepurchased from Cambridge Isotope Laboratories. Trifluoroacetic acid (>99%) was purchased from BeanTown Chemical. Triethylamine (>99%) was purchased from Fischer Scientific. N- hydroxy succinimide (98%) was purchased from Oakwood Chemical. l-(3- Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) (>99%) was purchased from AK Scientific. BDCA was synthesized according to the literature procedure.

[0093] Resin Preparation: The five porogen mixtures were 100:0, 80:20, 50:50, 20:80, 0: 100 wt% cyclohexanol to 1 -decanol. A nonporous resin mixture free of porogens was also made up. The resins were prepared in the dark by wrapping a 20 mL scintillation vial in aluminum foil. For formulations containing BDCA-MA, the vial was charged with BDCA- MA followed by the porogen. This was then vortexed until complete dissolution of the monomer into the porogen was achieved. Finally, a stock solution of TPGDA containing 2 wt% BAPO relative to monomer was added. This mixture was then vortexed briefly prior to printing to ensure resin homogeneity.

[0094] Synthesis of 2,5-Dioxopyrrolidin-l-yl l-{2-[(2-methylprop-2- enoyl)oxy]ethyl] butanedioate (MA-OSu). A-hydroxysuccinimide (590 mg, 5.17 mmol) and mono-2-(methacryloyloxy)ethyl succinate (1 mL, 5.17 mmol) were added to a two-neck round bottom flask equipped with a magnetic stir bar, inlet adapter, and septum and dissolved in CH2Q2 (25 mL), followed by the addition of A-(3-dimethylaminopropyl)-A'- ethylcarbodiimide hydrochloride (EDC) (1 g, 5.17 mmol) dissolved in CH2CI2 (10 mL). The solution was stirred at room temperature under nitrogen for 6 h before washing with 10% NFLCltaq) and saturated NaHCO3(aq) in a separatory funnel. The organic layer was then dried over anhydrous MgSCh, filtered, and concentrated under reduced pressure. The residue was purified using flash chromatography with silica gel as the stationary phase and 40% ethyl acetate / 60% hexanes as the eluent. Concentrating the desired band under reduced pressure provided MA-OSu as a colorless liquid (1.44 g, 85%). ’H NMR (400 MHz, CDCh): d = 6.11 (s, 1 H), 5.58 (s, 1 H), 4.40-4.29 (m, 4H), 2.82 (s, 4H), 2.80-2.73(m, 2H), 1.93 (s, 3H).13C NMR (100 MHz, CDCh): S = 170.88, 169.01, 167.73, 167.19, 135.97, 126.23, 62.86, 62.34, 28.71, 26.33, 25.66, 18.37. ESLHRMS: m / z = 345.1292 ([M+NH4]+), (calcd. 345.1292).

[0095] Synthesis of tert-Butyl (l,3-bis(2-(dicyclohexylamino)-2-oxoethoxy)propan-2- yl)carbamate (BDCA-Boc). BDCA-BOC was prepared following a previously reported procedure and characterized using 'H and ESI-HRMS.]H NMR (400 MHz, CDCI3): d= 5.68 (br, 1H), 4.12-4.02 (m, 4H), 3.85 (br, 1H), 3.74-3.51 (m, 4H), 3.31 (br, 2H), 2.91 (br, 2H),2.44 (br, 4H), 1.89-1.56 (m, 17H), 1.52-1.40 (m, 16H), 1.36-0.98 (m, 13H). ESI-HRMS: m / z = 656.4600 ([M+Na]+), (calcd. 656.4609).

[0096] Synthesis of 2-[(2-Methylprop-2-enoyl)oxy]ethyl 3-({ 1,3- bis[(dicyclohexylcarbamoyl)methoxy]propan-2-yl}carbamoyl)propanoate (BDCA-MA). BDCA-Boc was prepared following a previously reported procedure. Briefly, BDCA-Boc (200 mg, 0.316 mmol) was added to a two-neck round bottom flask equipped with a magnetic stir bar, inlet adapter, and septum containing CH2Q2 (10 mL) and allowed to dissolve. Subsequently, trifluoroacetic acid (10 mL) was slowly added to the solution. After stirring at room temperature under nitrogen for 2 h, the volatiles were removed under reduced pressure. The residue was dissolved in CH2CI2 (10 mL), neutralized with IN NaOH(aq), and then extracted with CH2CI2 (3x10 mL). The combined organic extracts were dried over anhydrous MgSCh before being filtered and concentrated under reduced pressure. The residue was redissolved in CH2Q2 (10 mL) and combined with a CH2Q2 (10 mL) solution containing MA-OSu (103 mg, 0.316 mmol) and allowed to react at room temperature for 6 h. After washing with saturated NaHCChijqi in a separatory funnel, the organic layer was dried over anhydrous MgSCU, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash chromatography using silica gel as the mobile phase and 80% ethyl acetate / 20% hexanes as the eluent. Concentrating the desired band under reduced pressure provided BDCA-MA as a colorless liquid (189 mg, 80%). ’H NMR (400 MHz, CDCI3): <5 = 8.04 (br, 1H), 6.12 (s, 1H), 5.58 (s, 1H), 4.43 (s, 4H), 4.16-4.07 (m, 5H), 3.80-3.70 (m, 2H), 3.63-3.51 (m, 2H), 3.23 (br, 2H), 2.92 (br, 2H), 2.75-2.65 (m, 2H), 2.61-2.52 (m, 2H), 2.43 (br, 4H), 1.94 (s, 3H), 1.85-1.74 (m, 9H), 1.72-1.63 (m, 3H), 1.54-1.42 (m, 8H), 1.35-1.04 (m, 13H).13C NMR (100 MHz, CDCI3): 3 = 172.23, 171.04, 167.86, 166.65, 135.52, 125.69, 70.36, 69.33, 62.05, 61.73, 56.35, 55.70, 49.23, 30.81, 30.42, 29.54, 29.09, 26.21, 25.52, 25.01, 24.83, 17.90. ESI-HRMS: m / z = 746.4947 ([M+H]+), (calcd. 746.4950).

[0097] Instrumentation and Characterization.

[0098] Nuclear Magnetic Resonance (NMR) Spectroscopy: NMR spectra were recorded on an Agilent MR 400 MHz spectrometer utilizing CDCI3 or G q as the solvent.1H NMR spectra were referenced to the signals for the residual protic impurities (observed at 7.26 ppm and 7.36 ppm respectively).13C NMR spectra were recorded in the decoupled mode and referenced to the chemical shifts of CDCI3 or CeDq, (at 77.16 ppm and 128.37 ppm respectively), as appropriate. Data are reported using the following multiplicity abbreviations: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet.

[0099] High Resolution Mass Spectrometry (HRMS): HRMS was performed on an Agilent Technologies 6530 Accurate-Mass Q-TOF LC / MS using APCI or ESI. The data was subsequently analyzed using the Agilent MassHunterQualitative Analysis Software.

[0100] Digital Light Processing (DLP) 3D Printer: amples were printed at an intensity of 8.6 mW / cnr, using a 1 second irradiation time per 25 pm layer. After printing, all samples were washed with EtOH, post-cured using 370 nm (part no. ANYCUBIC-WASH-CURE) for 6 minutes while maintaining the sample in a solution of ethanol, and then dried.

[0101] Critical Point Drier (CPD): Sample drying was carried out on a Quorum Technologies critical point drier. The solvent was exchanged with liquid carbon dioxide over the course of 40-60 minutes before the chamber was sealed and the temperature was raised to 37 °C to reach the supercritical point. This drying method preserved the integrity of the sample and prevented artifacts, such as pore collapse, that can occur during air-drying.

[0102] Scanning Electron Microscopy (SEM): SEM studies were carried out on a FEI Quanta 650 SEM / ESEM instrument at 5-10 kEv. SEM was used to examine the crosssection and surface characteristics of the 3D printed objects. For improved imaging, the samples were sputtered with Au / Pd (60:40) using an Electron Microscopy Science (EMS) sputter coater. Sputtering was conducted for 1.5 min at 40 mA. Energy dispersive X-ray spectroscopy (EDX) was carried out on Apreo 2 C LoVac SEM equipped with a Broker EDX system.

[0103] UV-Vis Absorption and Transmittance Spectroscopy: UV-vis absorption spectroscopy was performed with an optical fiber coupled spectrometer (QE PRO-ABS, Ocean Optics). Spectra were collected with a boxcar width of 5 and 5 scans to average. The spectrometer allowed measurements over the 200-950 nm spectral range, at an optical resolution of 1.7 nm, using a back-thinned, TE cooled, 1024x58 element CCD array. Tuned for absorption measurements, this system utilized a balanced deuterium-tungsten halogen light source (DH-2000-BAL) with a typical output of 194 pW (deuterium bulb) and 615 pW (tungsten bulb) through a SubMiniature version A (SMA) 905 connector, covering a range from 230 nm-2.5 pm. Multimode fiber-optic cables with SMA connectors on both ends and a 600 pm core diameter (QP600-025-SR) connected the light source to the sample holder. For solution measurements a cuvette holder (QNW QPOD 2eTM) capable of magnetic stirring and Peltier-driven temperature control from -30 °C to 105 °C was used. For thin-film absorption measurements, a reflection-transmission sample stage from Ocean Insight (STAGE-RTL-T) was used. The sample holder was coupled through a multimode fiber to aspectrometer (QE PRO-ABS) having an entrance slit of 5 pm (INTSMA-005 Interchangeable Slit). Transmittance measurements were performed directly on the polymer film using the Ocean Optics software. Measurements were taken at three places on the film and averaged. For kinetic experiments, a quartz cuvette with a stirring well (Type IMS Macro Cuvette with Magnetic Stirrer Slot, fireflysci) and modified with a septa screw-top was used.

[0104] Compression Testing was carried out using a Shimadzu Autograph AGS-X universal testing machine equipped with a 10 kN load cell. Samples were measured with calipers at three points and averaged to determine the height and contact area for analysis. Compression was carried out at 0.5 mm / min (~10% / min) until failure.

[0105] Pore Size Analysis: In order to determine the pore area and structure from the SEM images, ImageJ software was employed. The images were converted to a binary image, inverted, and the threshold of all images was adjusted to 175 / 255. To calculate the area inside the pores, the ImageJ particle analysis software was used with reference made to the image scale bar for measurements. For each composition, three images were analyzed at a magnification of ~25,000x and used to generate an average and calculate the standard deviation of the nanopore diameter. The diameter was calculated from the measured area from the ImageJ analysis assuming that the pores are, on average, geometrically circular.

[0106] Nitrogen Adsorption and Brunauer-Emmett-Teller (BET) Analysis: All samples were activated under reduced pressure at 70 °C for 15 hours prior to gas sorption experiments. All isotherms were recorded on a Quantachrome Autosorb iQ setup at 77 K. N2 (99.995+%) was purchased from Praxair. Samples for gas sorption were printed, and dried cylinders measuring with a 22 mm x 3 mm (height x diameter) geometry were selected. Surface area was determined using the BET equation with three runs of the same sample to determine an average and standard deviation.

[0107] Polymer Density: Nonporous poly(TPGDA) polymer density, pp. was measured using an Archimedes density kit at ambient conditions and calculated as:where msoiis the mass of the dry polymer submerged in an auxiliary solvent, and pSoi is the density of the auxiliary solvent at ambient conditions. Heptane (pSoi = 0.684 g / cm), a hydrophobic and non-polar solvent, was selected as the reference solvent since solvent uptake for this medium should be negligible during the associated measurements. These measurements were carried out with three individual samples to obtain an average value.Porous polymer densities were measured by 3D printing three solid 5 mm x 5 mm x 5 mm cubes and drying with CPD. The samples were measured with calipers to determine volume and an analytical balance was used to determine mass. Densities were averaged between three samples to provide a standard deviation.

[0108] Conductivity: An Oakton CON 550 replacement conductivity cell K = 1 probe was used for the conductivity measurements. Conductivity standards 84 pS / cm, 1413 pS / cm, and 12.89 84 mS / cm purchased from Oakton were used to calibrate the probe. Deionized water that has a conductivity < 1 .0 pS / cm was used.

[0109] Attenuated Total Reflectance Infrared (ATR-IR) Spectroscopy: ATR-FTIR spectra were recorded on an Infinity Gold FTIR equipped with a ZnSe crystal at the Texas Materials Institute at The University of Texas at Austin (UT Austin).

[0110] Thermogravimetric Analysis (TGA): TGA were performed on a TA Instruments TGA Q500 with a heat ramp of 5.00 °C / min to 30 °C, isothermal for 15 mins, and heat ramp of 5.00 °C / min to 800 °C.

[0111] Differential Scanning Calorimetry (DSC): DSC was performed using a TA Instruments DSC2500 using the modulated heat only method ramping at 3.00 °C / min with a range starting at -90 °C and ending at 200 °C.

[0112] Inductively Coupled Plasma Mass Spectrometry: ICP-MS analyses were made using the quadrupole ICP-MS lab at the Jackson School of Geoscience (UT Austin) using an Agilent 7500ce inductively coupled plasma mass spectrometer.

[0113] Elemental Analysis: Combustion elemental analyses were carried out by Atlantic Microlab in Norcross, GA with a Carlo Erba 1108 elemental analyzer.

[0114] X-Ray Analysis: X-ray analysis of single crystals was performed on a Rigaku Oxford Synergy-S with a HyPix6000E detector using Cu Kot radiation source (A, = 1.5418 A) with collimating mirror monochromators.

[0115] This disclosure further encompasses the following aspects.

[0116] Aspect 1 : A porous polymer structure comprising: a nanoporous polymer matrix comprising repeating units derived from a support monomer and receptor monomer capable of bonding with a metal; wherein the nanoporous polymer matrix comprises a plurality of nanopores having an average pore diameter of 1 to 1000 nanometers.

[0117] Aspect 2: The porous polymer structure of aspect 1 , wherein the support monomer comprises a crosslinker comprising at least two polymerizable groups, preferably atleast two ethylenically unsaturated polymerizable groups, more preferably (meth)acrylate groups.

[0118] Aspect 3 : The porous polymer structure of aspect 1 or 2, wherein the support monomer comprises an alkylene glycol diacrylate, preferably tripropylene glycol diacrylate.

[0119] Aspect 4: The porous polymer structure of any of aspects 1 to 3, wherein the receptor monomer comprises an ethylenically unsaturated polymerizable group, preferably a (meth) acrylate group, and at least one receptor group capable of bonding with the metal.

[0120] Aspect 5: The porous polymer structure of any of asepcts 1 to 4, wherein the metal comprises cobalt, nickel, lithium, manganese, arsenic, a trivalent lanthanide, preferably neodymium or dysprosium, or a trivalent group 13 metal, preferably, gallium, or indium.

[0121] Aspect 6: The porous polymer structure of aspect 4 or 5, wherein the at least one receptor group capable of bonding with the metal comprises a dicyclohexylamide receptor group.

[0122] Aspect 7: The porous polymer structure of any of aspects 1 to 6, wherein the receptor group capable of bonding with the metal comprises a bis-cyclohexylamide group, preferably wherein the receptor monomer has the structure

[0123] Aspect 8: The porous polymer structure of any of aspects 1 to 6, wherein the receptor group capable of bonding with the metal comprises a tris-cyclohexylamide group,preferably wherein the receptor monomer has the structure

[0124] Aspect 9: The porous polymer structure of any of aspects 1 to 6, wherein the receptor group capable of bonding with the metal comprises a hemispherand or crown ether- strapped calix[4]pyrrole.

[0125] Aspect 10: The porous polymer structure of any of aspects 1 to 6, wherein the receptor group capable of bonding with the metal comprises a glycolamide, chelidonic acid, or dipicolinic acid.

[0126] Aspect 1 1 : The porous polymer structure of any of aspects 1 to 6, wherein the receptor group capable of bonding with the metal comprises an Fe(III) hydroxypyridinone.

[0127] Aspect 12: The porous polymer structure of any of aspects 1 to 11, wherein the nanoporous polymer matrix has a three-dimensional lattice structure comprising a plurality of channels having an average channel diameter of 1 micrometer to 10 millimeters,

[0128] Aspect 13: The porous polymer structure of any of aspects 1 to 12, wherein the nanoporous polymer matrix has a kelvin lattice structure or a gyroid lattice structure.

[0129] Aspect 14: The porous polymer structure of any of aspects 1 to 13, wherein the plurality of nanopores has an average pore size of 50 to 500 nanometers, or 80 to 280 nanometers.

[0130] Aspect 15: The porous polymer structure of any of aspects 1 to 14, wherein repeating units derived from the receptor monomer are present in the polymer network in an amount of 1 to 50 weight percent, or 1 to 20 weight percent, or 1 to 10 weight percent, each based on the total weight of the polymer network.

[0131] Aspect 16: The porous polymer structure of any of aspects 1 to 15, wherein the porous polymer structure is prepared by an additive manufacturing process, preferably by digital light processing.

[0132] Aspect 17: A method for the manufacture of the porous polymer structure of any of aspects 1 to 16, the method comprising: providing a resin mixture comprising: the support monomer; the receptor monomer; a photoinitiator; and a porogen; and irradiating the resin mixture with light to provide the porous polymer structure.

[0133] Aspect 18: The method of aspect 17, wherein the porogen is present in an amount of 1 to 90 weight percent, based on the total weight of the resin mixture.

[0134] Aspect 19: The method of aspect 17 or 18, wherein the photoinitiator is capable of initiating polymerization when irradiated with visible light or ultraviolet light.

[0135] Aspect 20: The method of any of aspects 17 to 19, further comprising removing the porogen.

[0136] Aspect 21: The method of any of aspects 17 to 20, wherein the porogen comprises cyclohexanol, 1 -decanol, or a combination thereof.[0137| Aspect 22: A method of binding a target metal species, the method comprising: contacting a fluid mixture comprising the target metal species with the porous polymer structure of any of claims 1 to 16 or the porous polymer structure made by the method of any of aspects 17 to 21.

[0138] Aspect 23: The method of aspect 22, wherein the contacting is in the presence of a solvent that increases the binding efficiency of the target metal species to the receptor, preferably an alcoholic solvent, more preferably ethanol or isopropanol.

[0139] Aspect 24: The method of any of aspects 22 to 23, further comprising releasing captured target metal species by contacting the porous polymer network comprising the captured target metal species with a solvent that decreases the binding efficiency of the target metal species to the receptor, preferably water.

[0140] Aspect 25: The method of any of aspects 22 to 24, wherein the target metal species is cobalt, nickel, lithium, manganese, arsenic, a trivalent lanthanide, preferably neodymium or dysprosium, or a trivalent group 13 metal, preferably, gallium or indium.

[0141] Aspect 26: A system for removing a target metal species from a fluid mixture, the system comprising: a feed vessel comprising the fluid mixture comprising the target metal species and having an inlet and an outlet; a pump in fluid communication with the outlet of the feed vessel wherein the pump is capable of conveying the fluid mixture to a cartridgecomprising the porous polymer structure of any of aspects 1 to 16; wherein an outlet of the cartridge is fluidly connected to the inlet of the feed vessel.

[0142] Aspect 27: The system of aspect 26, further comprising an in situ monitoring loop for analyzing the concentration of metal species in the fluid mixture.

[0143] Aspect 28: The system of aspects 26 or 27, comprising one or more cartridges fluidly connected in series, wherein each cartridge comprises a porous polymer structure capable of binding a different target metal species.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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 orconflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0148] 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.

[0149] 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), C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C1-6 haloalkyl, C1-9 alkoxy, C1-6 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, C1-6 alkyl sulfonyl (-S(=O)2-alkyl), C6-12 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.

[0150] 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. A porous polymer structure comprising: a nanoporous polymer matrix comprising repeating units derived from a receptor monomer capable of bonding with a metal, and optionally, a support monomer; wherein the nanoporous polymer matrix comprises a plurality of nanopores having an average pore diameter of 1 to 1000 nanometers.

2. The porous polymer structure of claim 1 , wherein the support monomer is present and comprises a crosslinker comprising at least two polymerizable groups, preferably at least two ethylenically unsaturated polymerizable groups, more preferably (meth)acrylate groups.

3. The porous polymer structure of claim 1 , wherein the receptor monomer comprises an ethylenically unsaturated polymerizable group, preferably a (meth)acrylate group, and at least one receptor group capable of bonding with the metal.

4. The porous polymer structure of claim 1 , wherein the metal comprises cobalt, nickel, lithium, manganese, arsenic, a trivalent lanthanide, preferably neodymium or dysprosium, or a trivalent group 13 metal, preferably, gallium or indium.

5. The porous polymer structure of claim 3, wherein the at least one receptor group capable of bonding with the metal comprises a dicyclohexylamide receptor group.

6. The porous polymer structure of claim 1 , wherein the receptor group capable of bonding with the metal comprises a bis-cyclohexylamide group, preferably wherein the receptor monomer has the structurea tris-cyclohexylamide group, preferably wherein the receptor monomer has the structure7. The porous polymer structure of claim 1 , wherein the receptor group capable of bonding with the metal comprises a hemispherand or crown ether-strapped calix[4]pyrrole; or a glycolamide, chelidonic acid, or dipicolinic acid; or an Fe(III) hydroxypyridinone.

8. The porous polymer structure of claim 1 , wherein the nanoporous polymer matrix has a three-dimensional lattice structure comprising a plurality of channels having an average channel diameter of 1 micrometer to 10 millimeters,9. The porous polymer structure of claim 1 , wherein the nanoporous polymer matrix has a kelvin lattice structure or a gyroid lattice structure.

10. The porous polymer structure of claim 1 , wherein the plurality of nanopores has an average pore size of 50 to 500 nanometers, or 80 to 280 nanometers.

11. The porous polymer structure of claim 1 , wherein repeating units derived from the receptor monomer are present in the polymer network in an amount of 1 to 100 weight percent, or 1 to 99 weight percent, or 1 to 90 weight percent, or 1 to 50 weight percent, each based on the total weight of the polymer network.

12. The porous polymer structure of claim 1 , wherein the porous polymer structure is prepared by an additive manufacturing process, preferably by digital light processing.

13. A method for the manufacture of the porous polymer structure of claim 1 , the method comprising: providing a resin mixture comprising: the receptor monomer; optionally, the support monomer; a photoinitiator capable of initiating polymerization when irradiated with visible light or ultraviolet light; and a porogen; and irradiating the resin mixture with light to provide the porous polymer structure.

14. The method of claim 13, wherein the porogen is present in an amount of 1 to 90 weight percent, based on the total weight of the resin mixture.

15. The method of claim 13, further comprising removing the porogen.

16. A method of binding a target metal species, the method comprising: contacting a fluid mixture comprising the target metal species with the porous polymer structure of claim 1.

17. The method of claim 16, wherein the contacting is in the presence of a solvent that increases the binding efficiency of the target metal species to the receptor, preferably an alcoholic solvent, more preferably ethanol or isopropanol.

18. The method of claim 16, further comprising releasing captured target metal species by contacting the porous polymer network comprising the captured target metalspecies with a solvent that decreases the binding efficiency of the target metal species to the receptor, preferably water.

19. A system for removing a target metal species from a fluid mixture, the system comprising: a feed vessel comprising the fluid mixture comprising the target metal species and having an inlet and an outlet; a pump in fluid communication with the outlet of the feed vessel wherein the pump is capable of conveying the fluid mixture to a cartridge comprising the porous polymer structure of claim 1 ; wherein an outlet of the cartridge is fluidly connected to the inlet of the feed vessel; and wherein the system optionally further comprises an in situ monitoring loop for analyzing the concentration of metal species in the fluid mixture.

20. The system of claim 19, comprising one or more cartridges fluidly connected in series, wherein each cartridge comprises a porous polymer structure capable of binding a different target metal species.

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