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    • 专利摘要:
    Magnetic graphene oxide-based metal adsorbent composite material and production process. The present invention relates to a metal adsorbent composite material comprising: - a hybrid material comprising - coated magnetic nanoparticles modified with amino groups and/or hydroxyl groups on their surface, coupled to graphene oxide by physical forces and amide or ester type covalent bonds; said magnetic graphene oxide activated by the introduction of acid groups; and - an alkylpolyamine to which said activated magnetic graphene oxide is bound by covalent bond; and - a ligand comprising a chelating functional group, said ligand being bound to the hybrid material by said alkylpolyamine. The invention also relates to the process for obtaining said composite material and its use in the decontamination and treatment of spills. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2844942A1
    申请号:ES202030050
    申请日:2020-01-22
    公开日:2021-07-23
    发明作者:Leal Pablo Montoro；Mesa Juan Carlos Garcia；Guerrero María Del Mar Lopez；Alonso Elisa Isabel Vereda
    申请人:Universidad de Malaga；
    IPC主号:
    专利说明:

    [0001] Magnetic graphene oxide based metal adsorbent composite material and production process
    [0003] TECHNICAL SECTOR
    [0005] The present invention belongs to the nanotechnology sector. It is intended to provide a synthesis with which to prepare a magnetic graphene oxide and, on the other, to present a new adsorbent nanomaterial with specific functionalization that has been synthesized from it. In addition, said material offers the possibility of use in two main applications, decontamination and treatment of spills; and recycling of high-priced materials.
    [0007] BACKGROUND OF THE INVENTION
    [0009] Nanomaterials are of great interest to industry and technology due to their unique physico-chemical properties, high surface area, and highly active surface locations, which make them incredibly useful for a wide range of applications. Among them, magnetic nanoparticles (MNPs) and graphene oxide (GO) are of great interest.
    [0011] MNPs are a new type of nanometric material that are attracted to a magnetic field, however, they do not retain residual magnetism when the magnetic field disappears. In recent years, many studies have been carried out on MNPs for their potential applications as magnetic carriers in the field of medicine, decontamination of wastewater, preconcentration of both anions and cations, etc. Among the existing MNPs, those of iron oxide (magnetite, Fe3O4, and maghemite, and-Fe2O3) are those that have received the most attention, due to their biocompatibility, biodegradability, physiological and chemical stability, low toxicity and strong magnetic response. This last property allows to carry out a variant of the traditional solid phase extraction, called magnetic solid phase extraction (MSPE). Suspended superparamagnetic nanoparticles attached to the target species can be collected and separated from the matrix very quickly by using a magnetic field. This characteristic makes them very useful for separation processes (figure 1), whose advantages are a reduced analysis time, biocompatibility, require fewer reagents and allow the automation of analytical methodologies.
    [0013] Graphene is another nanomaterial that has attracted great scientific interest due to its unique graphite atomic plane, honeycomb structure, large surface area, and remarkable physical properties. Its theoretical surface area is 2,630 m2 / g, which suggests a high adsorption capacity. Graphene oxide (GO) is easily obtained from natural graphite by a chemical oxidation process, which separates the layers of C with oxygen-containing molecules, making it easily exfoliable in water. It presents a two-dimensional layered nanostructure, with a rich delocalized n-n electron system that makes it strongly interact with organic compounds with benzene rings. On the other hand, the presence of several functional groups with oxygen (carbonyls, hydroxyl and epoxy) on GO is responsible for strong van der Waals interactions and hydrogen bonds, which determines a high adsorption towards metal ions.
    [0015] The adsorption on GO is very remarkable, but tedious, slow and requires high sample volumes. To solve these problems, MNPs can be coupled on the GO sheets and the extraction can be carried out quickly by means of a magnetic field, without the need to filter or centrifuge. 1-3 GO bound to MNPs (magnetic graphene oxide, MGO) seems to be a excellent adsorbent.4,5 The combination of graphene sheets with MNPs has remarkable properties such as greater dispersion of the nanoparticles (less aggregates are formed), large surface area, strong superparamagnetism and excellent extraction capacity. However, despite the improvements provided by coupling, the resulting material would be limited in its applications as an extractant due to the lack of selectivity of both MNPs and GO. For this reason, many authors resort to their functionalization with chelating organic groups that increase the selectivity towards metal ions.
    [0017] Some examples of materials that combine graphene or graphene oxide with magnetic nanoparticles are shown in:
    [0018] • US2013099153 (A1), which discloses a hybrid material comprising graphene and iron oxide for use in wastewater treatment.
    [0019] • CN103723788 (A), which discloses a method for adsorbing heavy metals using manganese and ferrite nanoparticles and a graphene compound.
    [0020] • US2013344237 (A1), which discloses graphene nanocomposites with iron nanoparticles doubly coated with a layer of iron oxide and a layer of an amorphous compound with Si-SO bond.
    [0021] • WO2014094130 (A1), which discloses a product for fixing heavy metals. The product is graphene oxide nanoparticles alone or combined with magnetic particles.
    [0022] • CN105413647 (A), which discloses a method for preparing a material composed of graphene oxide and chitosan.
    [0024] Therefore, none of these documents mention a coupling of magnetic nanoparticles with graphene oxide and modification to obtain covalent bonds.
    [0026] To our knowledge, there is no method that combines the double covalent functionalization of the material (functionalize both MNPs and GO), in addition to the double MNPs-GO coupling (chemical -through covalent bond- and physical -by electrostatic interactions and van forces. der Waals-).
    [0028] References:
    [0029] 1. Azam, S., Mohammad, A., Microchim. Acta, 182 (2015) 257.
    [0030] 2. Wan Ibrain, W.A., Rashide Nodeh, H., Hassan, Y.A.E., Sanagi, M.M. Crit. Rev.
    [0031] Anal. Chem., 45 (2015) 270.
    [0032] 3. Yadollah, Y., Mohammad, F., Mahmaz, A., Microchim. Acta, 182 (2015) 1491. 4. Rashidic Nodeh, H., Wan Ibrain, W.A., Ali, I., Marsin Sanagi, M. Environ. Sci.
    [0033] Pollut. Res., 23 (2016) 9759.
    [0034] 5. Qi, T., Huang, C., Yan, S., Li n, X-J., Pan, S-Y. Talanta, 144 (2015) 1116.
    [0035] 6. Diagboya, P.N., Ohu-Owolabi, B.I., Abebowale, K.O. RSC Advances, vol. 5 (2015) 2536.
    [0036] 7. Islam, A., Ahmad H., Zaidi, N., Kumar, S. Microchim. Acta, vol. 183 (2016) 289.
    [0037] 8. Wierucka, M., Biziuk, M. TRAC-Trend Anal. Chem., 59 (2014) 50.
    [0038] 9. Du, D., Wang, L., Shao, Y., Wang, J., Engelhard, M.H., Lin, Y. Anal. Chem., 83 (2011) 746.
    [0040] DESCRIPTION OF THE INVENTION
    [0041] As used herein M @ GO-LG means "functionalizable magnetic graphene oxide bound to a ligand according to the definition shown below.
    [0043] LG stands for "ligand".
    [0045] The present invention relates to a composite material, M @ GO-LG, metal adsorbent comprising:
    [0046] • a hybrid material, M @ GO, comprising activated magnetic graphene oxide, MGO-A, covalently linked to at least one first coupling reagent, which is an alkylpolyamine; in which MGO-A is MGO activated by the introduction of acid groups, and MGO is magnetic GO, formed by coated MNPs, modified with at least amino groups (NH2) and / or hydroxyl groups (OH) on their surface, coupled by physical forces and covalent bonds to GO, where the covalent bond is an amide or ester bond between amino or hydroxyl groups of the modified coated MNPs and acid groups present in the GO sheets; Y
    [0047] • a ligand (LG) comprising a chelating functional group, said ligand being bound to M @ GO by at least said first coupling reagent, thus forming the composite material, M @ GO-LG, object of the invention.
    [0049] The M @ GO hybrid material can be defined as functionalizable MGO.
    [0051] GO has hydroxyl (OH) and epoxy groups, but it also has acid (COOH) groups. The latter are the ones used to form the amide or ester and couple the magnetic nanoparticles. After this coupling between GO and MNPs, by which the MGO has been obtained, the OH groups are oxidized to CH2COOH and the epoxy groups present to -O-CH2-COOH. In this way, the MGO-A is obtained, that is, MGO with additional acid groups which can be attached to the chelating ligand through the reagent of coupling.
    [0053] The material of the invention combines always covalent double functionalization (there is a covalent bond between the ligand and the MNPs, and there is also a covalent bond between the ligand and the GO), and the double coupling between MNPs and GO (covalent and dispersive).
    [0055] The fact that there are covalent bonds between the different components of the M @ GO-LG composite material increases its useful life as an extractant.
    [0057] The ligand comprises atoms with at least one lone electron pair, capable of coordinating with a metal center.
    [0059] According to particular embodiments, the ligand comprises nitrogen, oxygen, sulfur atoms or combinations of them.
    [0061] According to particular embodiments, the ligand may be selected from a compound derived from thiocarbonohydrazide, ethylenediamine tetraacetic acid -EDTA-, ammonium pyrrolidinedithiocarbamate -APDC-, methylthiosalicylate -TS- and sulfanilic acid.
    [0063] According to particular embodiments, the ligand is a compound derived from thiocarbonohydrazide selected from 1,5-bis (2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-, (1,5-bis- (di-2-pyridyl) methylene thiocarbonohydrazide -DPTH-, 1,5-bis [henyl- (2-pyridyl) methylene] thiocarbonohydrazide -BPTH- and 1,5-bis (2-pyridyl) methylene thiocarbonohydrazide -PMTH-.
    [0065] In the composite material of the invention there are n -n interactions between the electron cloud of the GO sheet and the aromatic system of the introduced chelating ligand.
    [0067] In the case of ligands with the functional group C = S, C = O, the ligand exhibits a tautomerization equilibrium of the carbon-heteroatom bond, such as C = S / C-SH. The tautomerization equilibrium shifts towards the C-SH species, which presents the most widespread electronic system. Being a more reduced form of S or O, the chelating characteristics of the ligand are improved.
    [0068] MNPs can be nanoparticles of iron, nickel, cobalt, or nanoparticles of one or more chemical compounds of these elements. According to particular embodiments, the MNPs are iron oxides obtained from their salts; among Fe (II) salts: FeCh, FeBr2, Feh FeCO3, Fe (NOs) 2, FeO, FeSO4, and among Fe (NI) compounds, for example, FeCh, FeBr3, Feh, Fe ( NO3) 3, Fe2O3, Fe2 (SO4) 3 and preferably, are magnetite. According to additional particular embodiments, the nanoparticles can be CoFe2O4; CoZnFe2O4; NiO.
    [0070] The size of the nanoparticles (before being coated and modified) can be between 10 and 25 nm, preferably between 13 and 18 nm.
    [0072] The MNPs in the composite material of the invention, M @ GO-LG, are coated with a material selected from inorganic polymers, biopolymers such as chitosan, silicon compounds and aluminas. Silicon compounds include silicas (eg, mesoporous silica, controlled pore glass, silica gel). According to a preferred embodiment, they are coated with silica, and more preferably with mesoporous silica, for which tetraethylorthosilicate -TEOS- is preferably used.
    [0074] The coated MNPs are further modified with a compound selected from silane, silanol, siloxane or polyxylosan, such that said compound has at least one nitrogen functional group. Preferably said compound is an aminoalkylalkoxysilane, preferably aminoalkyltrialkoxysilane, more preferably aminopropyltrimethoxysilane.
    [0076] The coupling reagent can be:
    [0077] - any alkylpolyamine, such as, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or
    [0078] - an alkylpolyamine linked to a polyaldehyde.
    [0080] The polyaldehyde can be, for example, glutaraldehyde, butanedial, propanedial.
    [0082] According to preferred embodiments this first coupling reagent is EDA (ethylenediamine), and, more preferably, it is EDA linked to a polyaldehyde, preferably glutaraldehyde as the second coupling reagent.
    [0083] According to a preferred embodiment, the composite material (M @ GO-LG) comprises: • a hybrid material, M @ GO, comprising activated magnetic graphene oxide (MGO-A), bound to the coupling reagents EDA and glutaraldehyde, in the that EDA is linked to glutaraldehyde; in which MGO-A is MGO activated by the introduction of acid groups, and MGO is magnetic graphene oxide, formed by magnetite MNPs coated with silica, modified with at least amino groups on their surface, coupled by physical forces and covalent bonds a GO, where the covalent bond is an amide bond between amino groups of the modified coated magnetite MNPs and acid groups present on GO sheets; Y
    [0084] • the ligand is selected from:
    [0085] or 1,5-bis (2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-;
    [0086] PSTH being linked to M @ GO by EDA and glutaraldehyde, giving rise to M @ GO-PS;
    [0087] or (1,5-bis- (di-2-pyridyl) methylene thiocarbonohydrazide -DPTH-; DPTH being linked to M @ GO via EDA and glutaraldehyde, giving rise to M @ GO-DP;
    [0088] or 1,5-bis [henyl- (2-pyridyl) methylene] thiocarbonohydrazide -BPTH- being BPTH linked to M @ GO via EDA and glutaraldehyde, giving rise to M @ GO-BP; Y
    [0089] or 1,5-bis (2-pyridyl) methylene thiocarbonohydrazide -PMTH-, PMTH being linked to M @ GO by EDA and glutaraldehyde, giving rise to M @ GO-PM.
    [0091] Especially preferably, the ligand is 1,5-bis [(2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-, and, in the resulting composite, M @ GO-PS, the PSTH is bound to M @GO using EDA and glutaraldehyde,
    [0093] The present invention also relates to a hybrid material, M @ GO, comprising activated magnetic graphene oxide (MGO-A), linked by covalent bond to at least one first coupling reagent, which is an alkylpolyamine
    [0094] • where MGO-A is MGO activated by entering groups acid, and
    [0095] • MGO is magnetic GO, formed by coated MNPs, modified with at least amino groups (NH2) and / or hydroxyl groups (OH) on their surface, coupled by physical forces and covalent bonds to GO, in which the covalent bond is a amide or ester linkage between amino or hydroxyl groups of the modified coated NMPs and acid groups present in GO sheets.
    [0097] In the M @ GO hybrid material defined, the MNPs can be selected from nanoparticles of iron, nickel, cobalt, and nanoparticles of chemical compounds of these elements. Examples of MNPs can be the same as defined above for the composite material of the invention.
    [0099] In the M @ GO hybrid material defined, the MNPs can be coated, as already defined above, with a material selected from inorganic polymers, biopolymers such as chitosan, silicon compounds and aluminas. Examples of silicon compounds can be the same as defined above for the composite material of the invention.
    [0101] In the defined M @ GO hybrid material, the coated MNPs may be modified as defined above.
    [0103] In the M @ GO hybrid material the first coupling reagent is an alkylpolyamine and preferably the alkylpolyamine is EDA.
    [0105] According to a preferred embodiment, the M @ GO hybrid material comprises activated magnetic graphene oxide (MGO-A), linked to the first EDA coupling reagent, • wherein MGO-A is MGO activated by the introduction of acid groups, and
    [0106] • MGO is magnetic GO, formed by magnetite MNPs coated with silica, modified with at least amino groups on their surface, coupled by physical forces and covalent bonds to GO, in which the covalent bond is an amide bond between amino groups of the Modified silica-coated magnetite MNPs and acid groups present in the sheets by GO.
    [0108] The present invention also relates to a precursor material, M @ GO-RA, comprising the hybrid M @ GO material defined above linked to a second coupling reagent, such as a polyaldehyde, for example, glutaraldehyde, butanedial, propanedial, and wherein the first coupling reagent, alkylpolyamine, is attached to the second coupling reagent.
    [0110] According to particular embodiments, the precursor material M @ GO-RA, comprises the hybrid material M @ GO defined above linked to glutaraldehyde, M @ GO-Glut, through alkylpolyamine, preferably EDA.
    [0112] The present invention also relates to an intermediate precursor material M @ GO-RA linked to thiocarbonohydrazide (M @ GO-Glut-THC).
    [0114] The present invention also refers to an activated magnetic graphene oxide (MGO-A) consisting of MGO activated by the introduction of acid groups where MGO is magnetic GO, formed by coated MNPs, modified with at least amino groups (NH2) and / or hydroxyl groups (OH) on their surface, coupled by physical forces and covalent bonds to GO, in which the covalent bond is an amide or ester bond between amino or hydroxyl groups of the modified coated MNPs and acid groups present in the sheets by GO.
    [0116] The MGO-A material comprises MGO and acid groups (COOH) attached to it.
    [0118] According to a preferred embodiment, activated magnetic graphene oxide, MGO-A, consists of activated MGO where MGO is magnetic GO, formed by magnetite MNPs coated with silica, modified with at least amino groups on their surface, coupled by physical forces and bonds. covalent to GO, where the covalent bond is an amide bond between amino groups of the modified coated magnetite MNPs and acid groups present on GO sheets.
    [0120] The present invention also relates to a method for preparing the M @ GO-LG composite, defined above, comprising:
    [0121] • reacting activated magnetic graphene oxide (MGO-A), with at least one first coupling reagent, which is a polyalkylamine, obtaining the product M @ GO;
    [0122] • make the product resulting from the previous step react with:
    [0123] or a ligand comprising a chelating functional group, or
    [0124] or previously, with a second coupling reagent, and then with a ligand;
    [0125] such that said ligand binds to M @ GO through at least polyalkylamine as the first coupling reagent, obtaining the composite material M @ GO-LG.
    [0127] The method comprises, more specifically:
    [0128] a) modifying MNPs coated with amino or hydroxyl functional groups, obtaining modified coated MNPs;
    [0129] b) coupling the modified coated MNPs to GO both by physical coupling (by electrostatic interactions and van der Waals forces) and by using a coupling agent that forms an amide or ester bond, obtaining MGO;
    [0130] c) activate MGO by adding acid groups to the surface of GO sheets, obtaining activated MGO, MGO-A;
    [0131] d) bind at least one first coupling reagent, which is a polyalkylamine, to acid groups found on the surface of activated MGO, transforming them into anchoring points susceptible to functionalization, obtaining the M @ GO product; Y
    [0132] e) make the product of the previous stage react (M @ GO) with
    [0133] e1) a ligand comprising a chelating functional group, or
    [0134] e2) previously, with a second coupling reagent, and then with a ligand;
    [0135] such that said ligand binds to M @ GO through at least the first coupling reagent, obtaining the composite material M @ GO-LG.
    [0137] The binding of M @ GO to the ligand occurs through functional groups of the coupling reagents, amino groups of polyalkylamine (such as EDA), and, optionally, aldehyde groups of a polyaldehyde, such as glutaraldehyde.
    [0138] According to particular embodiments, step e2) comprises (after reaction with a second coupling reagent, preferably glutaraldehyde) a reaction with thiocarbonohydrazide.
    [0140] The magnetic nanoparticles can be coated with the materials that have been defined for the composite material of the invention, M @ GO-LG, and according to a preferred embodiment they are coated with silica, preferably mesoporous silica, and for this, tetraethylorthosilicate -TEOS- is used. . The way of coating the magnetic particles is conventional.
    [0142] The coated magnetic nanoparticles can be modified with a compound selected from silane, silanol, siloxane or polysiloxane, such that said compound has at least one nitrogen functional group, preferably said compound being an aminoalkylalkoxysilane.
    [0144] According to a preferred embodiment, the modification of the coated MNPs comprises:
    [0145] • mixing the MNPs coated with an aminoalkylalkoxysilane, preferably aminoalkyltrialkoxysilane, more preferably aminopropyltrimethoxysilane in alcohol; said alcohol is preferably ethanol;
    [0146] • adjust the pH to 4.5 with acid, preferably acetic acid;
    [0147] • heating the mixture between 50 and 70 ° C, preferably at 60 ° C, for a time between 1 and 3 hours, preferably 2 hours under an inert atmosphere, obtaining modified coated nanoparticles.
    [0149] According to particular embodiments of the method of the invention, the coupling of the modified MNPs to the GO is carried out in the presence of a coupling agent, preferably said agent being N, N'-dicyclohexylcarbodiimide (DCC), which forms an amide bond.
    [0151] According to particular embodiments of the method, a coupling of modified coated magnetite nanoparticles and GO is carried out, for which the modified, coated MNPs are suspended in alcohol, preferably ethanol, in a organic solvent, preferably N, N'-dicidohexylcarbodiimide (DCC), stirring for a time between 30 and 50 hours, preferably between 40 and 50, more preferably, 48 hours, obtaining a covalent anchor in addition to the physical adsorption between GO and coated MNPs.
    [0153] MNPs can be prepared and the MNPs are coupled with GO, as well as obtaining a material with MGO bound to a ligand, using other procedures6 or functionalizing only the GO sheet through the COOH groups, synthesizing the MNPs by coprecipitation and dispersing them on the GO sheet in the same medium.7
    [0155] MGO is activated by introducing acid groups on the surface of GO, for example, by a reaction of MGO with sodium chloroacetate. Activation of MGO with additional acidic groups allows for as many anchors as possible on the surface, and subsequent reaction with a coupling reagent allows binding to the ligand.
    [0157] The preparation of the hybrid material, M @ GO, comprises:
    [0158] a) modifying MNPs coated with amino or hydroxyl functional groups, obtaining modified coated MNPs;
    [0159] b) coupling the modified coated MNPs to the GO both physically (by electrostatic interactions and van der Waals forces) and by using a coupling agent that forms an amide or ester bond, obtaining MGO;
    [0160] c) activate MGO by adding acid groups to the surface of the graphene oxide sheets, obtaining activated MGO, MGO-A; Y
    [0161] d) bind at least one first coupling reagent, which is a polyalkylamine, to acid groups found on the surface of activated MGO, transforming them into anchoring points susceptible to functionalization, obtaining the M @ GO product.
    [0163] The coating of the nanoparticles, the modification of the coated nanoparticles and the activation of the GO, is carried out with the materials that have been mentioned above in the description of the hybrid material and by reactions and / or methods known.
    [0165] The preparation of the M @ GO-RA precursor material comprises:
    [0166] • obtain the hybrid material M @ GO as defined above, and • make it react with a second coupling reagent, such as a polyaldehyde, for example glutaraldehyde, butanedial, propanedial, in an aqueous acid medium (such as, for example , in glacial acetic acid) at reflux.
    [0168] The preparation of the intermediate precursor material M @ GO-RA-THC comprises:
    [0169] • obtain the M @ GO-RA precursor material, as defined above; Y
    [0170] • make it react with thiocarbonohydrazide in an aqueous acid medium (such as, for example, in glacial acetic acid) at reflux.
    [0172] BRIEF DESCRIPTION OF THE FIGURES
    [0174] Figure 1. Scheme of extraction of an analyte (for example, metals or organic compounds) in magnetic solid phase according to the state of the art8, and using a material according to the present invention, comprising:
    [0175] 1) Dispersion of M @ GO-PS in the sample from which metals are to be extracted.
    [0176] 2) Adsorption of the analyte on the material.
    [0177] 3) Magnetic separation of the matrix material from the sample.
    [0178] 4) Elution of the analyte.
    [0179] 5) Magnetic separation of the regenerated material.
    [0181] Figure 2. Scheme showing the modification of GO with sodium chloroacetate according to the state of the art9.
    [0183] Figure 3. Schematic of functionalizable magnetic graphene oxide (M @ GO). LG = Ligand, (RA) -LG = ligand-bound coupling reagent
    [0185] Figure 4. Structure of the PSTH ligand. Tautomeric equilibrium C = S (A) / C-SH (B).
    [0187] Figure 5. Structure of the DPTH ligand. Tautomeric equilibrium C = S (A) / C-SH (B).
    [0188] Figure 6A. The surface morphology of M @ GO-PS observed by TEM at 200 nm scale.
    [0190] Figure 6B. The surface morphology of M @ GO-DP observed by TEM at 200 nm scale.
    [0192] Figure 7. Nitrogen adsorption / desorption isotherms observed for M @ GO-PS.
    [0194] Figure 8. Nitrogen adsorption / desorption isotherms observed for M @ GO-DP.
    [0196] Figure 9. XPS spectrum of sulfur in the material exhibiting the unexpected interactions (A) and XPS spectrum of "usual" sulfur of the PSTH ligand (B).
    [0198] Figure 10. XPS spectrum of sulfur in the material exhibiting the unexpected interactions (A) and the "usual" XPS spectrum of sulfur of the DPTH ligand (B).
    [0200] EXAMPLES OF EMBODIMENT OF THE INVENTION
    [0202] Example 1
    [0204] Process to chalk the functionalizable graphene oxide (M @ GO)
    [0206] Synthesis of MNPs from magnetite
    [0208] Ferric and ferrous salts (such as chlorides) are dissolved in a 2: 1 molar ratio (ferric: ferrous) in ultrapure water. This solution is placed in a three-necked round bottom flask which is placed in an ultrasound bath. The reaction is carried out under reflux and in an inert atmosphere. The ultrasound equipment is started to vigorously stir the solution and heat it to between 70 and 85 ° C. Once this temperature is reached, NH3 at 30% (V / V) is added and the inert atmosphere is reestablished. After 75 min, the reaction is stopped and the suspension obtained is allowed to cool to room temperature. The magnetite nanoparticles obtained are first washed with water, then with a 0.02 M sodium chloride solution and finally with ethanol. This washing sequence is carried out several times, always recovering the nanoparticles from the suspension with the help of a magnet placed at the bottom of the flask, decanting the supernatant liquid. After the wash, the MNPs are stored in ethanol.
    [0210] Coating with mesoporous silica
    [0212] First, 8 ml of tetraethyl orthosilicate (TEOS), whose chemical formula is Si (OC2H5) 4, is mixed with 60 ml of glycerol and 200 ml of ethanol in a 500 ml beaker using ultrasound shaking. The pH of the mixture is adjusted to 4.5 by adding acetic acid-sodium acetate buffer. This mixture is transferred to the three necked round bottom flask together with the previously prepared magnetite suspension. It is stirred with ultrasound, refluxing at 60 ° C in an inert atmosphere for two hours. Afterwards, it is allowed to cool to room temperature and the suspension is washed (decanting with the help of a magnet) sequentially as follows:
    [0214] 1. Washing with deionized water.
    [0215] 2. Washing with methanol.
    [0217] The solid obtained in the previous step is diluted in 150 ml of a 1% solution of y-aminopropyltrimethoxysilane (AP) in 95% ethanol and the pH is adjusted to 4.5 with acetic acid. This mixture is transferred to a 1 L three necked round bottom flask and heated at 60 ° C for two hours under a nitrogen atmosphere with stirring. Once this time has elapsed, the nanoparticles obtained are decanted with the help of the magnet, and washed twice with deionized water and twice with methanol. The powder obtained is left to dry in a desiccator at room temperature.
    [0219] The result of this operation is the coated and modified MNPs. The objective of the coating with silica is twofold: to protect the magnetite from ambient oxygen, in addition to providing an anchor point through the amino group of y- aminopropyltrimethoxysilane (AP).
    [0221] A way to synthesize magnetite nanoparticles is disclosed in González Moreno et al. (New J. Chem., 2017, 41.8804-8811).
    [0223] A procedure for coating nanoparticles with silica is described in Vereda Alonso et al. (Talanta 153 (2016) 228-239).
    [0225] MNPs-GO coupling
    [0227] 500 mg of GO (synthesized from graphite by the oxidation and exfoliation process of Diagboya et al. 6 ) are suspended in 50 ml of ethanol together with 500 mg of coated and modified MNPs from the previous step and 0.25 g of N , N'-dicyclohexylcarbodiimide (DCC) suspended in 50 ml of ethanol. The mixture is sonicated for 10 minutes and refluxed at 50 ° C for 48 h. In this way, part of the MNPs will be attached to the GO sheet covalently through an amide bond, which is formed by condensation between surface acid groups of GO and amino groups of the MNPs. Part of the MNPs will not be covalently anchored due to two factors: performance of the reaction or due to the depletion of the active sites of GO, so the rest will disperse on the sheet. Therefore, MNPs will be coupled to GO through two mechanisms: covalent bond by condensation with carboxylic acid groups and Van der Waals forces by interaction with the adsorbent GO sheet itself. The resulting product is called MGO.
    [0229] Activation of MGO
    [0231] The MGO solid from the previous step is taken and suspended in 50 ml of deionized water in a 500 ml beaker. The mixture is kept sonicated for 15 minutes and 5 g of NaOH (50 ml) are added. Subsequently, 5 g of sodium chloroacetate (Cl-CHsCOONa) (in 50 ml) are introduced and the mixture is kept for 2 h under ultrasound at room temperature. The suspension is separated with the use of magnets and washed by resuspending the solid up to two times in water. This modification allows the increase of the active sites on the surface of GO, by transforming the -OH groups into -CH2COOH and the epoxide groups into functionalizable -O-CH2COOH groups (Figure 2).
    [0233] EDA-MGO coupling
    [0234] The solid MGO activated (MGO-A) from the previous step is suspended in 50 ml of ethanol together with 4 ml of ethylenediamine (EDA) and 0.25 g of DCC in a 100 ml round bottom flask, and refluxed at 50 ° C for 48 h. The synthesized solid is called M @ GO. The acid groups from the previous step will condense with the amino group, giving rise to amide bonds. In this way, we have free amino groups that act as double origin anchor points, the amino group of the coated MNPs dispersed on the sheet and the remaining non-condensed amino of the EDA group. Therefore, we can functionalize both MNPs and GO.
    [0236] The synthesis yield of magnetic graphene oxide is 95%. The scheme of this material, M @ GO, is observed in figure 3. In figure 3 the M @ GO is all that is observed except the ligand ("Si" with three circles on the oxygen atoms -red circles- ).
    [0238] M @ GO functionalization process
    [0240] Starting from the magnetic graphene oxide activated in the previous step, M @ GO functionalization is carried out to introduce ligands. We introduce the functional group [1,5-bis (2-pyridyl) 3-sulfophenyl methylene] thiocarbonohydrazide (PSTH) following the reaction steps:
    [0242] Step 1, synthesis of 2-benzoyl ( 3'-sulfophenyl) pyridine. 2 g of 2-benzoylpyridine are weighed out and placed in a 100 ml round bottom flask. The flask is placed in an ice bath in an extractor hood and 20 ml of 30% fuming sulfuric acid are added until all the solid dissolves. The reaction is maintained for two hours and allowed to cool to room temperature. Finally, the contents of the flask are slowly and carefully poured into 180 ml of cold ether (4 ° C). A whitish precipitate forms which is then recrystallized from the minimum amount of ethanol / water 1: 1; obtaining whitish acicular crystals.
    [0244] Step 2, synthesis of M @ GO-Glut. 250 mg of M @ GO are weighed into a flask and 20 ml of 1% glutaraldehyde in water and 5 drops of glacial acetic acid are added. It is refluxed for 4 hours, decanted with the help of a magnet and washed with deionized water.
    [0246] Step 3, synthesis of M @ GO-Glut-THC. The synthesized M @ GO-Glut are placed in a flask and 20 ml of 0.5% thiocarbonohydrazide in water and 5 drops of glacial acetic acid are added. It is refluxed for 24 hours, decanted with the help of the magnet and washed with deionized water.
    [0248] Step 4, synthesis of M @ GO-PS. M @ GO-Glut-THC is placed in a flask and benzoyl (3'-sulfophenyl) pyridine, synthesized in the first step of this stage, dissolved at 0.25 % in ethanol / water (40/30), is added. The reaction is refluxed for 24 hours. Once this time has elapsed, it is magnetically decanted, washed with ethanol and left to dry in a desiccator for 2 days.
    [0250] The functionalization efficiency of magnetic graphene oxide with PSTH is 85%. The structure of the PSTH ligand is seen in Figure 4A. The material resulting from this process is called M @ GO-PS.
    [0252] Characterization of the adsorbent material M @ GO-PS
    [0254] Transmission electron microscopy ( TEM) and N2 adsorption isotherms
    [0256] The morphology of the M @ GO-PS surface was characterized by the adsorption / desorption isotherms of N2 and TEM. In the TEM images (figure 6A) it can be clearly observed that the Fe3O4 nanoparticles are coupled disorderly on the GO sheet with a diameter between 12-20 nm. The size of the nanoparticles was deliberately selected, since the smallest particles (<6 nm) show a rapid saturation of the magnetization and reduced magnetic susceptibility, while the large particles are difficult to disperse and have a smaller active surface. From the nitrogen adsorption experiments, it can be observed that the isotherms are of type IV (figure 7), typical of mesoporous materials (pore size between 20-500 Á). In Table 1 it can be seen that, indeed, the materials are mesoporous and have a higher surface area than the uncoupled GO (2,630 m2 / g).
    [0257] Table 1 Morphological information of the material
    [0259] Material M @ GO-PS
    [0260] Pore size ( Á) 96.36
    [0261] Surface area ( m2 / g) 19.58
    [0263] Mass spectrometry
    [0265] Table 2 Peak assignment of the MS spectrum
    [0267] Peak (m / z) Fragment
    [0271] 129
    [0273] 207
    [0275] From the MS spectra, the characteristic peaks of the PSTH ligand fragments were assigned (Table 2). The peaks m / z = 129 and m / z = 207 were found, both related to the presence of thiocarbonohydrazide, a reagent used in the synthesis by PSTH. Furthermore, peak (m / z = 64) was attributed to the loss of SO2 due to the presence of the sulfonic group in the structure.
    [0277] X-ray photoelectron spectroscopy
    [0279] Two peaks are observed in the M @ GO-PS spectrum of sulfur (Figure 9A). The first one (more energetic) is wider and corresponds to the sum of two contributions due to the presence of the sulfonic group (-SO3H) and the group C = S. The second least energetic peak is attributed to the tautomerization equilibrium of the C = S / C-SH bond. In the case of our material, the peak corresponding to the C-SH bond clearly presents a greater intensity compared to the equivalent peak in the spectrum of the ligand without anchoring to the material (Figure 9B). It can be concluded that the tautomeric equilibrium shifts preferentially towards one of the tautomeric forms (Figure 4A, 4B). The main explanation for this fact is the presence of electronic interactions between the n -n system of GO and the aromatic system of the functional group, favoring that tautomer with the most widespread electronic system.
    [0281] The chelating capacity of the ligand is directly related to the presence of N and S atoms in the structure, since the unpaired electrons of its valence shell can interact with the empty orbitals of metal cations. These unexpected interactions enhance the chelating capacity of the PSTH ligand, because the lower tautomeric form of sulfur (-C-SH versus C = S) is favored. In this way, the unpaired electrons of this atom would be more accessible in the formation of complexes.
    [0283] The XPS data were especially striking, as they revealed the presence of unexpected interactions in the M @ GO-LG material, specifically M @ GO-PS, which modifies the chemical properties of the ligand.
    [0285] Example 2
    [0287] Obtaining M @ GO-DP
    [0289] M @ GO functionalization process
    [0290] From the activated magnetic graphene oxide, obtained as described in example 1, the functionalization is carried out to introduce in this case, the ligand 1,5-bis di (2-pyridyl) methylene thiocarbonohydrazide (DPTH) following reaction steps:
    [0292] Step 1. Prepare M @ GO-Glut ( M @ GO-RA) as described in Example 1. Step 2. Prepare M @ GO-Glut-THC. as described in example 1.
    [0293] Step 3, synthesis of M @ GO-DP. Finally, the M @ GO-Glut-THC obtained was placed in a round bottom flask and a 2% solution of di-2-pyridylketone in ethanol was added, kept at reflux for 24 h. At the end of this time, the product was decanted, washed with ethanol and left to dry in a desiccator.
    [0295] The functionalization efficiency of magnetic graphene oxide with DPTH is 90%. The structure of the DPTH ligand is seen in Figure 5A. The material resulting from this process is called M @ GO-DP.
    [0297] Characterization of the adsorbent material M @ GO-DP
    [0299] Transmission electron microscopy ( TEM) and N2 adsorption isotherms
    [0301] The M @ GO-DP surface morphology was characterized by the adsorption / desorption isotherms of N2 and TEM. In the TEM images (figure 6B) it can be clearly observed that the Fe3O4 nanoparticles are coupled disorderly on the GO sheet with a diameter between 12-20 nm. The size of the nanoparticles was deliberately selected, since the smallest particles (<6 nm) show a rapid saturation of the magnetization and reduced magnetic susceptibility, while the large particles are difficult to disperse and have a smaller active surface. From nitrogen adsorption experiments, it can be observed that the isotherms are type IV (figure 8), typical of mesoporous materials (pore size between 20-500 Á). In table 3 it can be observed that, indeed, the materials are mesoporous and have a higher surface area than the uncoupled GO (2,630 m2 / g).
    [0302] Table 3 Morphological information of the material
    [0303] Material M @ GODP
    [0304] Pore size ( Á) 95.60
    [0305] Surface area ( m2 / g) 37.88
    [0307] Mass spectrometry
    [0308] Table 4 Peak assignment of the MS spectrum
    [0309] Peak (m / z) Fragment
    [0310] 129
    [0312] 184
    [0315] From the MS spectra, the characteristic peaks of the DPTH ligand fragments were assigned (Table 4). The peaks m / z = 129 and m / z = 207 were found, both related to the presence of thiocarbonohydrazide, a reagent used in the synthesis of DPTH. Furthermore, the peak (m / z = 184) was attributed to the use of di-2-pyridylketone during the synthesis of the ligand.
    [0317] X-ray photoelectron spectroscopy
    [0319] Two peaks are observed in the M @ GODP spectrum of sulfur (Figure 10A). The first of them (more energetic) corresponds to the group C = S. The second least energetic peak is attributed to the tautomerization equilibrium of the C = S / C-SH bond. In the case of our material, the peak corresponding to the C-SH bond clearly presents a higher intensity compared to the equivalent peak in the spectrum of the ligand without anchoring to the material (Figure 10B). It can be concluded that the tautomeric equilibrium shifts preferentially towards one of the tautomeric forms (Figure 10A, 10B). The main explanation for this fact is the presence of electronic interactions between the n -n system of GO and the aromatic system of the functional group, favoring that tautomer with the most widespread electronic system.
    [0321] The chelating capacity of the ligand is directly related to the presence of N and S atoms in the structure, since the unpaired electrons of its valence shell can interact with the empty orbitals of metal cations. These unexpected interactions enhance the chelating capacity of the DPTH ligand, because the lower tautomeric form of sulfur is favored (-C-SH versus C = S). In this way, the unpaired electrons of this atom would be more accessible in the formation of complexes.
    [0323] Material load capacities
    [0325] To study the adsorbent capacity of the new material, it was dispersed in a solution that contained both noble and transition metals. As a test of load capacity in the case of transition metals, e1Hg was chosen for the case of the M @ GO-PS material, or Pb for the case of the M @ GO-DP material due to the environmental interest it entails for its high toxicity, and the V for its relevance in the production of ferrovanadium alloys. Although it is true that V is very widespread in the earth's crust, it is not present at a high concentration, so the development of methodologies that allow the extraction and recovery of this element is of great interest. An example is the recovery of vanadium from biodiesel ash. On the other hand, in the case of noble metals, the adsorption capacity with Ag and Au, two highly valued elements with important applications in technology industries and jewelery, was studied.
    [0327] The metal samples were prepared by mixing 25 mg of the magnetic material and 50 ml of a solution of Hg, V, Ag and Au 10 mg / L in each metal for the case of the M @ GO-PS material, or 50 ml of a solution of Pb, V, Ag and Au 10 mg / L in each metal for the case of the M @ GO-DP material, buffered with pH 5 acetic acid / sodium acetate solution. The suspension was stirred for 10 min in ultrasound and left incubate the mixture for 24 hours. Finally, aliquots of the supernatant solution were taken after decanting with the magnet and the remaining metal concentration was measured with an inductively coupled plasma optical emission spectrometer (ICP-OES). The load capacity was calculated as the difference between what was initially added and what was found after extraction. Tables 5A and 5 B show the loading or adsorption capacity in mg / g of M @ GO-PS and M @ GO-DP, where good loading capacities are observed for the four elements tested.
    [0329] Table 5A Loading capacity (mg / g) of M @ GO-PS.
    [0331] Element mg / g of
    [0333] Hg 7.5
    [0335] Ag 9.2
    [0336] Au 18.8
    [0337] Table 5B Loading capacity (mg / g) of M @ GO-DP.
    [0339] Element mg / g of
    [0340] M @ GO-DP.
    [0341] Pb 19.2
    [0345] Ag 18.5
    [0347] Au 16.9
    [0349] Advantages of the invention
    [0351] This innovative material is proposed for the treatment of spills in order to decontaminate or recycle high-value metals. Currently, at an industrial level, two main techniques are used: Chemical precipitation (Elimination of heavy metals making them insoluble with the addition of milk of lime, sodium hydroxide or other chemical reagents that raise the pH) and electrolytic reduction (causing deposition on the electrode pollutant; it is used to recover valuable elements).
    [0352] • Advantages against chemical precipitation: The separation by gravity between the matrix and the analytes is slow and tedious, in addition to the fact that it is necessary to alter the properties of the discharge. In our case, the separation would only require seconds after the application of the external magnetic field.
    [0353] • Advantages over electrolytic reduction: This technique usually requires large amounts of energy and very specific conditions for the recovery of each metal. For example, in the case of gold, a cell voltage of 8 V, current density 20 A / dm2, temperature> 60 ° C and an anode-cathode gap of 8 to 16 cm and a minimum pH of 10 are required. , electrolysis equipment usually operates when the metal concentration is in the mg / L range, while the proposed material is also capable of working with trace and ultra-trace concentrations (^ g / L), at which several of these elements are already toxic, given their bioaccumulative nature.
    [0354] As mentioned above, there are also nanomaterials with excellent adsorptive properties for metals, such as GO and MNPs. In the case of GO, its use can be slow and tedious due to its small particle size, having to resort to traditional separation methods to separate the dispersed material from the sample matrix (filtration, centrifugation, etc.).
    [0356] Table 6 shows the results of the elemental analysis of the four nanomaterials (MNPs-PSTH, 1-PSTH, 2-PSTH (prepared according to other procedures6,7) and M @ GO-PS). It can be seen that M @ GO-PS has a higher atomic percentage of S and N, which is why it is considered the best functionalized.
    [0358] Taking into account the characterization tests, the elemental analysis showed that the magnetic graphene oxide of the invention is more functionalizable compared to uncoupled MNPs.
    [0360] Table 6 Data obtained from the elemental analysis CNHS (atomic%) and Fe (% by weight)
    [0362] Sample% C% S% N% Fe MNPs-PSTH 4,796 3,347 0.985 66
    1-PSTH 7.259 0.469 0.795 38
    2-PSTH 31,703 2,227 4,328 36
    M @ GO-PS 48,535 3,823 6,154 18
    权利要求:
    Claims (34)
    [1]
    1. A composite material, M @ GO-LG, metal adsorbent comprising:
    • a hybrid material, M @ GO, comprising activated magnetic graphene oxide (MGO-A), covalently bonded to at least one first coupling reagent, which is an alkylpolyamine; in which MGO-A is MGO activated by the introduction of acid groups, and MGO is magnetic graphene oxide, formed by coated magnetic nanoparticles, modified with at least amino groups (NH2) and / or hydroxyl groups (OH) on their surface , coupled by physical forces and covalent bonds to graphene oxide, wherein the covalent bond is an amide or ester bond between amino or hydroxyl groups of the modified coated magnetic nanoparticles and acid groups present in the graphene oxide sheets; and • a ligand comprising a chelating functional group, said ligand being linked to M @ GO via at least said first coupling reagent.
    [2]
    2. The material according to claim 1, wherein the ligand comprises atoms with at least one lone electron pair, capable of coordinating with a metal center.
    [3]
    3. The material according to claim 2, wherein the ligand comprises nitrogen, oxygen, sulfur atoms or combinations thereof.
    [4]
    4. The material according to claim 2, wherein the ligand is selected from a compound derived from thiocarbonohydrazide, ethylenediamine tetraacetic acid -EDTA-, ammonium pyrrolidinedithiocarbamate -APDC-, methylthiosalicylate -TS- and sulfanilic acid; preferably a compound derived from thiocarbonohydrazide selected from 1,5-bis (2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-, (1,5-bis- (di-2-pyridyl) methylene thiocarbonohydrazide -DPTH-, 1,5-bis [phenyl- (2-pyridyl) methylene] thiocarbonohydrazide -BPTH- and 1,5-bis (2-pyridyl) methylene thiocarbonohydrazide -PMTH-.
    [5]
    5. The material according to any one of claims 1 to 4, wherein the magnetic nanoparticles are selected from nanoparticles of iron, nickel, cobalt, and nanoparticles of one or more chemical compounds of these elements, preferably the magnetic nanoparticles are iron oxides.
    [6]
    6. The material according to any one of claims 1 to 5, wherein the magnetic nanoparticles are coated with a material selected from inorganic polymers, biopolymers, silicon compounds and aluminas.
    [7]
    The material according to claim 6, in which the coated magnetic nanoparticles are modified with a compound selected from silane, silanol, siloxane or polyxylosan, such that said compound has at least one nitrogenous functional group capable of providing amino groups to the nanoparticles , preferably said compound is an aminoalkylalkoxysilane.
    [8]
    The material according to any one of claims 1 to 7, wherein the first coupling reagent is an alkylpolyamine, which is linked to a second coupling reagent, which is a polyaldehyde.
    [9]
    9. A composite material according to any one of claims 1 to 8 having a pore size between 80 and 110 Á, preferably between 95 and 100 Á and a surface area between 15 and 25 m2 / g, preferably between 18 and 20 m2 / g.
    [10]
    The composite material according to claim 1, comprising:
    • a hybrid material, M @ GO, comprising activated magnetic graphene oxide (MGO-A), linked to the coupling reagents EDA and glutaraldehyde, in which EDA is linked to glutaraldehyde; in which MGO-A is MGO activated by the introduction of acid groups, and MGO is magnetic graphene oxide, formed by magnetic nanoparticles of magnetite coated with silica, modified with at least amino groups on their surface, coupled by physical forces and bonds covalent to graphene oxide, wherein the covalent bond is an amide bond between amino groups of the modified coated magnetite magnetic nanoparticles and acid groups present in the graphene oxide sheets; and • the ligand is selected from:
    or 1,5-bis (2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-, with PSTH being linked to M @ GO by EDA and glutaraldehyde, giving place to M @ GO-PS;
    or (1,5-bis- (di-2-pyridyl) methylene thiocarbonohydrazide -DPTH-, with DPTH being linked to M @ GO via EDA and glutaraldehyde, giving rise to M @ GO-DP;
    or 1,5-bis [phenyl- (2-pyridyl) methylene] thiocarbonohydrazide -BPTH-, with BPTH being linked to M @ GO via EDA and glutaraldehyde, giving rise to M @ GO-BP; Y
    or 1,5-bis (2-pyridyl) methylene thiocarbonohydrazide -PMTH-, PMTH being linked to M @ GO by EDA and glutaraldehyde, giving rise to M @ GO-PM.
    [11]
    11. A hybrid material, M @ GO, comprising activated magnetic graphene oxide (MGO-A), covalently bonded to at least one first coupling reagent, which is an alkylpolyamine
    • where MGO-A is MGO activated by the introduction of acid groups, and
    • MGO is magnetic graphene oxide, formed by coated magnetic nanoparticles, modified with at least amino groups (NH2) and / or hydroxyl groups (OH) on their surface, coupled by physical forces and covalent bonds to graphene oxide, in which the covalent bond is an amide or ester bond between amino or hydroxyl groups of the modified coated magnetic nanoparticles and acid groups present in the graphene oxide sheets.
    [12]
    12. The M @ GO material according to claim 11, wherein the magnetic nanoparticles are selected from nanoparticles of iron, nickel, cobalt, and nanoparticles of one or more chemical compounds of these elements, preferably the magnetic nanoparticles are iron oxides.
    [13]
    The M @ GO material according to any one of claims 11 to 12, wherein the magnetic nanoparticles are coated with a material selected from inorganic polymers, biopolymers, silicon compounds and aluminas.
    [14]
    The M @ GO material according to claim 13, wherein the nanoparticles Coated magnets are modified with a compound selected from silane, silanol, siloxane or polyxylosan, such that said compound has at least one nitrogen functional group capable of providing amino groups to the nanoparticles, preferably said compound being an aminoalkylalkoxysilane.
    [15]
    The material according to claim 11, M @ GO, comprising activated magnetic graphene oxide (MGO-A), bound to the first EDA coupling reagent,
    • where MGO-A is MGO activated by the introduction of acid groups, and
    • MGO is magnetic graphene oxide, formed by magnetic nanoparticles of magnetite coated with silica, modified with at least amino groups on their surface, coupled by physical forces and covalent bonds to graphene oxide, in which the covalent bond is an amide bond between amino groups of modified coated magnetite magnetic nanoparticles and acid groups present in graphene oxide sheets.
    [16]
    16. A precursor material, M @ GO-RA, comprising the hybrid material M @ GO defined in one of claims 11 to 15, wherein the first coupling reagent, alkylpolyamine, is linked to a second coupling reagent, preferably a polyaldehyde.
    [17]
    17. A precursor material, M @ GO-Glut, according to claim 16, wherein the second coupling reagent is glutaraldehyde.
    [18]
    18. An intermediate precursor material, M @ GO-RA-THC, comprising the precursor material defined in claim 16, M @ GO-RA, bound to thiocarbonohydrazide.
    [19]
    19. An intermediate precursor material, M @ GO-Glut-THC, according to claim 18, wherein the second coupling reagent is glutaraldehyde.
    [20]
    20. A method for preparing the M @ GO-LG composite material defined in one of claims 1 to 10, comprising:
    • react activated magnetic graphene oxide (MGO-A), with al minus a first coupling reagent, which is a polyalkylamine, obtaining the product M @ GO,
    • make the product resulting from the previous step react with:
    or a ligand comprising a chelating functional group, or
    or previously, with a second coupling reagent, and then with a ligand;
    such that said ligand binds to M @ GO through at least polyalkylamine as the first coupling reagent, obtaining the M @ GO-LG composite material.
    [21]
    21. The method according to claim 20, comprising:
    a) modify coated magnetic nanoparticles (MNPs) with amino or hydroxyl functional groups, obtaining modified coated magnetic nanoparticles;
    b) coupling the coated, modified magnetic nanoparticles to graphene oxide by using a coupling agent that forms an amide or ester bond, physical coupling will also take place (by electrostatic interactions and van der Waals forces) obtaining MGO;
    c) activate MGO by adding acid groups to the surface of the graphene oxide sheets, obtaining activated MGO, MGO-A;
    d) bind at least one first coupling reagent, which is a polyalkylamine, to acid groups found on the surface of activated MGO, transforming them into anchoring points susceptible to functionalization, obtaining the M @ GO product; Y
    e) make the product of the previous stage react (M @ GO) with
    e1) a ligand comprising a chelating functional group, or
    e2) previously, with a second coupling reagent, and then with a ligand,
    such that said ligand binds to M @ GO through at least the first coupling reagent, obtaining the composite material M @ GO-LG.
    [22]
    22. The method according to claim 21, wherein the magnetic nanoparticles are selected from nanoparticles of iron, nickel, cobalt, and nanoparticles of chemical compounds of these elements.
    [23]
    23. The method according to claim 22, wherein the magnetic nanoparticles are coated with a material selected from inorganic polymers, biopolymers, silicon compounds and aluminas.
    [24]
    24. The method according to claim 23, wherein the coated magnetic nanoparticles are modified with a compound selected from silane, silanol, siloxane or polysiloxane, such that said compound has at least one nitrogen functional group, preferably said compound being an aminoalkylalkoxysilane.
    [25]
    The method according to claim 22, wherein the coupling of the modified magnetic nanoparticles to graphene oxide is carried out in the presence of DCC as a coupling agent that forms an amide bond.
    [26]
    26. The method according to claim 20, wherein the MGO is activated by introducing acid groups on the surface of the magnetic graphene oxide.
    [27]
    27. The method according to claim 26, wherein the introduction of acid groups on the surface of the graphene oxide is carried out by a reaction of MGO with sodium chloroacetate.
    [28]
    28. The method according to any one of claims 20 to 27, wherein the ligand comprises atoms with at least one lone pair of electrons, capable of coordinating with a metal center, preferably comprising nitrogen, oxygen, sulfur atoms or combinations of they.
    [29]
    29. The method according to claim 28, wherein the ligand is selected from a compound derived from thiocarbonohydrazide, ethylenediamine tetraacetic acid -EDTA-, ammonium pyrrolidinedithiocarbamate -APDC-, methylthiosalicylate -TS- and sulfanilic acid.
    [30]
    30. The method according to claim 29, wherein the ligand is selected from 1,5-bis [(2-pyridyl) -3-sulfophenyl methylene] thiocarbonohydrazide -PSTH-, (1,5-bis- (di-2 -pyridyl) methylene thiocarbonohydrazide -DPTH-, 1,5-bis [phenyl- (2-pyridyl) methylene] thiocarbonohydrazide -BPTH- and 1,5-bis [(2-pyridyl) methylene] thiocarbonohydrazide -PMTH-.
    [31]
    31. A process for preparing the hybrid material, M @ GO, defined in one of claims 11 to 15, comprising:
    a) modify coated magnetic nanoparticles (MNPs) with amino or hydroxyl functional groups, obtaining modified coated magnetic nanoparticles;
    b) coupling the coated, modified magnetic nanoparticles to graphene oxide by using a coupling agent that forms an amide or ester bond, obtaining magnetic graphene oxide, MGO;
    c) activate MGO by adding acid groups to the surface of the graphene oxide sheets, obtaining activated MGO, MGO-A; Y
    d) bind at least one first coupling reagent, which is a polyalkylamine, to acid groups found on the surface of activated MGO, transforming them into anchoring points susceptible to functionalization, obtaining the M @ GO product.
    [32]
    32. An M @ GO-LG composite material obtained by the method defined in one of claims 21 to 30.
    [33]
    33. Use of the material defined in one of claims 1 to 10 or of the material defined in one of claims 11 to 15, 16-17, or 18-19 as a noble metal or transition metal adsorbent.
    [34]
    34. Use of the material according to claim 33, in the decontamination and treatment of spills.
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    同族专利:
    公开号 | 公开日
    WO2021148700A1|2021-07-29|
    ES2844942B2|2021-11-24|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2011082064A1|2009-12-29|2011-07-07|Montclair State University|Chelating agent modified graphene oxides, methods of preparation and use|
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    ES202030050A|ES2844942B2|2020-01-22|2020-01-22|Magnetic graphene oxide-based metal-absorbing composite material and production process|ES202030050A| ES2844942B2|2020-01-22|2020-01-22|Magnetic graphene oxide-based metal-absorbing composite material and production process|
    PCT/ES2021/070039| WO2021148700A1|2020-01-22|2021-01-22|Metal-adsorbing composite material based on magnetic graphene oxide and method for obtaining same|
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