Composite material with polyfunctional groups as well as preparation method and application of composite material

Abstract

The invention relates to the field of water treatment, in particular to a composite material with polyfunctional groups and a preparation method and application thereof.The composite material with the polyfunctional groups contains at least two groups including carboxyl, amino, amido and hydroxyl and at least one group including sulfo and nitro; the composite material contains a cross-linked compound of a polymer I and a polymer II, and the polymer I is a carbon chain polymer and contains at least one group including a sulfonic acid group and a nitro group; and the polymer II is at least one of chitosan and a derivative thereof, and chitin and a derivative thereof. The composite material with multiple functional groups is preferably a composite fiber, has a synergistic adsorption effect of multiple functional groups, can effectively adsorb a complex heavy metal ion system in a water body, and is a heavy metal ion adsorbent which is high in adsorption efficiency, large in adsorption quantity and wide in applicable temperature range.

Description

Technical Field

[0001] This invention relates to the field of water treatment, specifically to a composite material with multiple functional groups, its preparation method, and its application. Background Technology

[0002] With the advancement of industrialization, environmental damage has intensified. Industrial wastewater containing heavy metal ions is a serious form of environmental pollution. This wastewater mainly originates from industrial activities such as mining, electroplating, papermaking, pharmaceuticals, and fertilizer production, and often contains large amounts of phosphorus (Pb). 2+ Zn 2+ Cu 2+ and Hg 2+ Plasma, if released without treatment, can alter geological lithology, damage vegetation and farmland soil, and further harm ecosystems and human health. Adsorption methods for removing heavy metal ions are easy to operate, highly efficient, low-cost, and reusable, making them widely used in heavy metal ion treatment. Researching adsorbents with even higher adsorption efficiency has been a hot research topic in recent years.

[0003] The principle behind the adsorption of heavy metal ions by polymeric adsorbents is the chelation effect between special polymeric groups, such as carboxyl, amino, sulfonic acid, and hydroxyl groups, and heavy metal ions, thereby reducing the concentration of heavy metal ions in water. According to the type of polymer, adsorbents can be divided into natural polymeric adsorbents and synthetic polymeric adsorbents. Natural polymeric adsorbents such as chitosan and cellulose have a certain adsorption capacity for heavy metals, but due to the limitations of their inherent structure on application performance, they need to be grafted with other compounds for acylation, etherification, esterification, and other modifications to improve chemical stability. Among synthetic polymeric adsorbents, those containing anhydride groups and amino groups are commonly used. Combining different functional groups can achieve adsorption of Pb. 2+ Zn 2+ and Cu 2+ Synergistic adsorption of heavy metal ions.

[0004] Currently reported polymeric adsorbents are mostly monofunctional and difunctional. PKRoy prepared a monofunctional adsorbent, maleic anhydride-styrene crosslinked copolymer, using divinylbenzene as a crosslinking agent. They found that when the initial concentration of the metal ion solution was 10 mg / L, the removal efficiency could reach over 96.5% (Journal of Applied Physics). PolymerScience, 94(4):1771-1779, 2010); Vieira et al. prepared a monofunctional cross-linked chitosan adsorption film that can be continuously recycled and reused using glutaraldehyde as a cross-linking agent, and the adsorption rate of Hg(II) in water can reach 65% (WaterResearch, 40(8):1726-1734, 2006); Su Huihui prepared maleic anhydride grafted modified cellulose derivatives by solid-phase synthesis and liquid-phase synthesis, which have both carboxyl and hydroxyl functional groups and have a good adsorption effect on divalent metal ions (Beijing Forestry University, 2012); Multifunctional adsorbents have also been reported, such as a gallic acid and polyethyleneimine trifunctional cross-linked heavy metal ion adsorbent disclosed in patent CN109174040A, which contains amino, carboxyl and hydroxyl groups and has a good adsorption effect on heavy metal ions. However, because its final form is a solid powder, there is a problem of difficult recycling in practical applications. Summary of the Invention

[0005] To address the above problems, this invention proposes a composite material with multiple functional groups, its preparation method, and its application. Preferably, the composite material with multiple functional groups is a composite fiber containing at least two groups selected from carboxyl, amino, amide, and hydroxyl groups, and at least one group selected from sulfonic acid and nitro groups. It has the synergistic adsorption effect of multiple functional groups, which can effectively adsorb complex heavy metal ion systems in water. It is a heavy metal ion adsorbent with high adsorption efficiency, large adsorption capacity, and wide applicable temperature range.

[0006] To achieve the above objectives, a first aspect of the present invention is to provide a composite material having multiple functional groups, comprising at least two groups including carboxyl, amino, amide and hydroxyl groups, and at least one group including sulfonic acid group and nitro group.

[0007] The composite material contains a crosslinked complex of polymer one and polymer two, wherein polymer one is a carbon chain polymer and contains at least one group including sulfonic acid group and nitro group;

[0008] The polymer 2 is at least one of chitosan and its derivatives, and chitin and its derivatives.

[0009] This invention is based on natural polymer adsorbents. Unlike the common practice of grafting small molecule compounds onto them for modification, this invention uses acid anhydride polymers to react with specific functional groups of natural polymers to obtain composite materials with cross-linked structures. Preferably, a one-step solution spinning method is used to prepare composite fibers with better adsorption effects, more stable chemical properties, and easier use and recycling. This fully leverages the synergistic effect of multiple adsorption groups to obtain products with better heavy metal adsorption performance. The rich functional groups can be further modified to give the product higher use value.

[0010] According to some preferred embodiments of the present invention, the polymer is derived from at least one copolymer raw material selected from sulfonated and / or nitrated copolymers of the following: acid anhydride copolymers; preferably,

[0011] The anhydride copolymer is selected from at least one of maleic anhydride copolymer, itaconic anhydride copolymer, and citraconic anhydride copolymer.

[0012] According to some more preferred embodiments of the present invention, the structure of the copolymer raw material is as shown in formula (I), containing structural unit A and structural unit B;

[0013] Where x, y, and z are all natural numbers, x>1, y+z≥0, preferably at least one of y and z is 0; more preferably y=z=0;

[0014] The structural unit A is derived from at least one of maleic anhydride, itaconic anhydride, and citraconic anhydride, preferably maleic anhydride;

[0015] The structural unit B is derived from a monomer containing isolated carbon-carbon double bonds, preferably a monomer having the formula (II):

[0016]

[0017] The Y1 group is one of H, —CH3, —CH2CH3, and —CH(CH3)2; the Y2 group is an alkyl group having 2 to 8 carbon atoms. One of the following; the alkyl group having 2 to 8 carbon atoms is preferably one or more of —CH2CH3, —CH2CH2CH3, —CH(CH3)2, —CH2(CH3)CH2CH3, and —CH2CH2CH2CH3.

[0018] According to some more preferred embodiments of the present invention, the sulfonic acid group (-SO3H) and nitro group (-NO2) in the composite material are connected to the Y2 group of structural unit B.

[0019] According to some preferred embodiments of the present invention, the polymer is derived from at least one copolymer raw material selected from sulfonated and / or nitrated copolymers of the following:

[0020] At least one of maleic anhydride-styrene alternating copolymer, maleic anhydride-α-methylstyrene alternating copolymer, maleic anhydride-vinyl formate copolymer, maleic anhydride-vinyl acetate copolymer, maleic anhydride-vinyl propionate copolymer, maleic anhydride-vinyl butyrate copolymer, and maleic anhydride-acrylic acid copolymer, more preferably at least one of maleic anhydride-styrene alternating copolymer and maleic anhydride-α-methylstyrene alternating copolymer.

[0021] According to the present invention, the polymer 2 is selected from at least one of chitosan and / or its derivatives, chitin and / or its derivatives, preferably at least one of chitosan, chitin, carboxymethyl chitin, acylated chitosan, alkylated chitosan, and quaternized chitosan; more preferably at least one of chitosan, acylated chitosan, carboxylated chitosan, and quaternized chitosan.

[0022] The chitosan used in this invention can be selected from a wide range. Preferably, in order to facilitate obtaining a coagulation bath solution using chitosan as a raw material, chitosan with a degree of deacetylation of 50% or more is preferred, such as 50%, 55%, 60%, 65%, 70%, 80%, 90%, 95%, any two values ​​or any range of any two values, and 95% or more.

[0023] The degree of deacetylation of chitosan (DD) is the percentage of sugar residues in a chitosan molecule that have been deacetylated out of the total number of sugar residues in the chitosan molecule.

[0024] For example, acylated chitosan is selected from at least one of N-acylated chitosan and O-acylated chitosan; alkylated chitosan is selected from at least one of N-alkylated chitosan and O-alkylated chitosan.

[0025] The above-mentioned chitosan, chitin, carboxymethyl chitin, acylated chitosan, alkylated chitosan, and quaternized chitosan are all commercially available products.

[0026] According to the present invention, the composite material has a cross-linked structure and contains a cross-linked complex of polymer one and polymer two. According to some preferred embodiments of the present invention, polymer one and polymer two are separated by amide groups. Crosslinking.

[0027] According to some preferred embodiments of the present invention, the weight ratio of polymer one to polymer two in the composite material is 1:(1-10), for example, the ratio of 1 to 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10 and any two values ​​or any range of any two values, preferably 1:(1-2.5).

[0028] According to some preferred embodiments of the present invention, the total content of carboxyl, amino, amide, hydroxyl, sulfonic acid and nitro groups in each g of the composite material is 2-10 mmol.

[0029] According to the present invention, the morphology of the composite material may be, but is not limited to, composite fibers. According to some preferred embodiments of the present invention, in order to have a higher specific surface area, facilitating the adsorption of heavy metals and promoting recycling, preferably, the composite material is a composite fiber; more preferably,

[0030] The diameter of the composite fiber is less than 300 μm, more preferably less than 200 μm, and even more preferably 15-25 μm.

[0031] According to some preferred embodiments of the present invention, the composite fiber is prepared by solution spinning.

[0032] More preferably, the solution spinning method uses a coagulation bath to form fibers from the spinning solution, wherein the spinning solution is a solution containing polymer one, and the coagulation bath is a solution containing polymer two.

[0033] A second aspect of the present invention is to provide a method for preparing a composite material having multiple functional groups, preferably used in the method for preparing a composite material having multiple functional groups as described in the first aspect, comprising:

[0034] A copolymer raw material containing at least one acid anhydride copolymer is subjected to sulfonation modification and / or nitration modification to obtain polymer one;

[0035] A first solution containing polymer one and a second solution containing polymer two are reacted to remove the solvent, thereby obtaining the composite material with multiple functional groups.

[0036] The polymer 2 is at least one of chitosan and its derivatives, and chitin and its derivatives.

[0037] According to some preferred embodiments of the present invention, the reaction between the first solution and the second solution is a solution spinning method; preferably, the solution spinning method uses a coagulation bath to make the spinning solution form fibers, the first solution is used as the spinning solution, the second solution is used as the coagulation bath, the spinning solution is in contact with the coagulation bath to obtain gel fibers, and then dried to obtain fibrous composite materials.

[0038] There are no restrictions on the solution spinning method; any solution spinning method in the prior art can be used. There are also no restrictions on the solution spinning equipment used; any solution spinning equipment in the prior art can be used. Preferably, an injection pump extrusion method is used. Preferably, the conditions for solution spinning include: a spinneret diameter of 0.1–400 μm; more preferably 0.1–300 μm; more preferably 0.1–200 μm.

[0039] More preferably, the nozzle diameter of the injection pump used for injecting into the coagulation bath is preferably 0.1 to 400 μm; more preferably 0.1 to 300 μm; and most preferably 0.1 to 200 μm; the injection speed of the injection pump used for injecting into the coagulation bath is preferably 0.01 to 1.5 mL / min; more preferably 0.01 to 1.0 mL / min; and most preferably 0.01 to 0.5 mL / min.

[0040] There is no limitation on the contact reaction temperature, such as the coagulation bath temperature during spinning. The present invention preferably uses a coagulation bath temperature range of 10℃ to 100℃, more preferably 20℃ to 100℃, and even more preferably 25℃ to 90℃. There is no limitation on the coagulation time, as long as it is sufficient to obtain multifunctional heavy metal ion adsorption fibers.

[0041] There are no restrictions on the diameter of the initial fibers prepared by solution spinning, but it is preferably less than 300 μm, and more preferably less than 200 μm. The smaller the fiber diameter, the better, because the larger the fiber aspect ratio, the better the adsorption effect of heavy metal ions. During solution spinning, the initial fibers can also be drawn after being extruded from the spinneret to make the fibers even finer.

[0042] According to some preferred embodiments of the present invention, the sulfonation modification method includes contacting the copolymer raw material with a sulfonating agent, preferably, the sulfonating agent is at least one selected from concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid and SO3 gas.

[0043] According to some preferred embodiments of the present invention, the nitration modification method includes contacting the copolymer raw material with a nitrifying agent, preferably, the nitrifying agent is fuming nitric acid.

[0044] The methods for sulfonation and nitration modification of the copolymer raw materials are existing technologies, including but not limited to the modification methods described in the embodiments of this invention.

[0045] According to some preferred embodiments of the present invention, the mass ratio of polymer one to polymer two is not greater than 1:0.1, preferably 1:(0.5-10), and more preferably 1:(1-5).

[0046] According to some preferred embodiments of the present invention, the anhydride copolymer is selected from at least one of maleic anhydride copolymers, itaconic anhydride copolymers, and citraconic anhydride copolymers.

[0047] Preferably, the structure of the anhydride copolymer is as shown in formula (I), containing structural unit A and structural unit B;

[0048]

[0049] Where x, y, and z are all natural numbers, x>1, y+z≥0, preferably at least one of y and z is 0; more preferably y=z=0;

[0050] The structural unit A is derived from at least one of maleic anhydride, itaconic anhydride, and citraconic anhydride, preferably maleic anhydride;

[0051] The structural unit B is derived from a monomer containing isolated carbon-carbon double bonds, preferably a monomer having the formula (II):

[0052]

[0053] The Y1 group is one of H, —CH3, —CH2CH3, and —CH(CH3)2; the Y2 group is an alkyl group having 2 to 8 carbon atoms. One of the following; the alkyl group having 2 to 8 carbon atoms is preferably one or more of —CH2CH3, —CH2CH2CH3, —CH(CH3)2, —CH2(CH3)CH2CH3, and —CH2CH2CH2CH3.

[0054] As an example, more preferably, the anhydride copolymer is at least one copolymer raw material selected from the following copolymers:

[0055] At least one of maleic anhydride-styrene alternating copolymer, maleic anhydride-α-methylstyrene alternating copolymer, maleic anhydride-vinyl formate copolymer, maleic anhydride-vinyl acetate copolymer, maleic anhydride-vinyl propionate copolymer, maleic anhydride-vinyl butyrate copolymer, and maleic anhydride-acrylic acid copolymer, more preferably at least one of maleic anhydride-styrene alternating copolymer and maleic anhydride-α-methylstyrene alternating copolymer.

[0056] According to the present invention, the polymer 2 is selected from at least one of chitosan and / or its derivatives, chitin and / or its derivatives, preferably at least one of chitosan, chitin, carboxymethyl chitin, acylated chitosan, alkylated chitosan, and quaternized chitosan; more preferably at least one of chitosan, acylated chitosan, carboxylated chitosan, and quaternized chitosan; and even more preferably chitosan with a degree of deacetylation of 50% or more.

[0057] For example, acylated chitosan is selected from at least one of N-acylated chitosan and O-acylated chitosan; alkylated chitosan is selected from at least one of N-alkylated chitosan and O-alkylated chitosan.

[0058] According to the present invention, the polymer is dissolved in a first solvent to obtain a first solution; according to some preferred embodiments of the present invention, the first solvent is water and / or an organic solvent capable of dissolving the polymer, preferably, the organic solvent is selected from at least one of acetone, tetrahydrofuran, and N,N-dimethylformamide.

[0059] There is no specific limitation on the concentration of the spinning solution, as long as it is sufficient to fully dissolve the polymer. According to some preferred embodiments of the present invention, the mass ratio of the polymer to the first solvent in the first solution is (1-50):100, more preferably (10-30):100.

[0060] According to the present invention, polymer II is dissolved in a second solvent to obtain a second solution. According to some preferred embodiments of the present invention, the mass ratio of polymer II to the second solvent in the second solution is (1-100):100, preferably (1-50):100, and more preferably (5-30):100.

[0061] According to some preferred embodiments of the present invention, the second solvent is a mixed solvent capable of dissolving polymer II. Preferably, the mixed solvent is at least one of aqueous acetic acid, aqueous sulfuric acid, and aqueous hydrochloric acid. More preferably, the volume ratio of solute to water in the mixed solvent is (1-100):100, preferably (1-4):100, and more preferably (5-20):100.

[0062] There are no specific restrictions on the mixing method of the spinning solution, and any mixing method in the existing disclosed technology can be used. There are also no restrictions on the mixing equipment used, and any mixing equipment in the existing technology can be used. Magnetic stirring is preferred.

[0063] The solution spinning method described herein employs a solution spinning method already disclosed in the prior art. Solution spinning requires the selection of a coagulation bath to promote fiber formation from the spinning solution. For ease of understanding, as an example: the coagulation bath in this invention is a solution, the solute being the polymer II; the solvent is a mixed solvent capable of dissolving the polymer II, and this invention uses at least one of the mixed solvents: aqueous acetic acid solution, aqueous sulfuric acid solution, and aqueous hydrochloric acid solution. The volume ratio of solute to water in the mixed solvent is (1–100):100, preferably (1–4):100, more preferably (5–20):100. The concentration of the coagulation bath is such that the mass ratio of polymer II to the mixed solvent is (1–100):100, preferably (1–50):100, more preferably (5–30):100.

[0064] A third aspect of the present invention is to provide a composite material with multiple functional groups as described in the first aspect or a composite material with multiple functional groups obtained by the preparation method described in the second aspect for use in the field of water treatment, preferably for metal ion adsorption, and more preferably for heavy metal ion adsorption.

[0065] As mentioned above, the composite material with multiple functional groups provided by the present invention is preferably a composite fiber. As a heavy metal ion adsorption fiber, the present invention crosslinks synthetic polymeric acid anhydride polymers with natural polymeric polymers and produces fibers through a one-step spinning method. The fibers can simultaneously contain at least two of the following groups: carboxyl, amino, hydroxyl, and amide groups, and at least one of the following groups: sulfonic acid and nitro groups. The synthetic polymers can provide carboxyl, amino, and sulfonic acid groups or nitro groups, while the natural polymers can provide amino, amide, and hydroxyl groups. It has the synergistic adsorption effect of multiple functional groups, which can effectively adsorb complex heavy metal ion systems in water. It is a heavy metal ion adsorbent with high adsorption efficiency, large adsorption capacity, and wide applicable temperature range.

[0066] The inventors of this invention, through research, believe that the adsorption principle of the composite material described in this invention is based on the fact that the monomers of acid anhydride copolymers, such as maleic anhydride, itaconic anhydride, and citraconic anhydride, can generate carboxyl groups after hydrolysis. The unbonded electrons on the oxygen atoms can coordinate with the empty orbitals on metal ions to form coordination adsorption. However, since acid anhydride monomers and their homologues are all electron-deficient monomers, they form copolymers with electron-rich monomers to improve their application value. Through copolymerization, acid anhydride copolymers with uniformly distributed functional groups can be obtained, such as maleic anhydride-styrene alternating copolymers, maleic anhydride-α-methylstyrene alternating copolymers, and maleic anhydride-acrylic acid copolymers. Further modification of the acid anhydride copolymers by sulfonation or nitration increases the number of structural units with adsorption functional groups, which can further improve the adsorption capacity of heavy metal ions. Natural polymer adsorbents, such as chitosan, have a large number of free amino and hydroxyl groups distributed along their backbone. These amino groups can be protonated in dilute acid solutions, resulting in a large number of positive charges on the molecular chains. These charges allow them to complex with heavy metal ions to form stable complexes. They can also form hydrogen bonds, covalent bonds, and coordinate bonds with non-heavy metal ions such as proteins, amino acids, nucleic acids, phenolic compounds, quinones, and fatty acids. However, chitosan tends to form gels in relatively low pH solutions. Therefore, cross-linking and grafting modifications are necessary to improve its mechanical strength and chemical stability over a wider pH range. This invention produces multifunctional heavy metal ion adsorbent fibers. Unlike grafting or cross-linking modifications of natural polymers using small molecules, this invention uses synthetic polymeric anhydride polymers to modify natural polymers, preparing multifunctional heavy metal ion adsorbent fibers with cross-linked structures. As composite fibers, these fibers have a larger adsorption surface area and better adsorption performance.

[0067] Compared with the prior art, the present invention has the following advantages:

[0068] (1) Multifunctional composite materials, preferably composite fibers, form an adsorption synergy between different types of functional groups, which can effectively improve the adsorption capacity of heavy metal ions.

[0069] (2) The composite fiber is suitable for use in a wide temperature range and can maintain good adsorption capacity of heavy metal ions at both below room temperature and at higher temperatures (such as 0 to 95°C).

[0070] (3) Unlike the grafting or cross-linking modification of natural polymers by small molecules, this invention selects to modify natural polymers with synthetic polymers to prepare a multifunctional wide-temperature heavy metal ion adsorption fiber with cross-linking structure, which is convenient to use and recycle.

[0071] (4) Fibers are prepared by solution spinning, which have a larger adsorption specific surface area and better adsorption effect. Attached Figure Description

[0072] Figure 1 This is an electron microscope image of the composite fiber with multiple functional groups obtained in Example 4.

[0073] Depend on Figure 1 As can be seen, the prepared fibers have a uniform diameter of 20 μm.

[0074] Electron micrographs of the composite fibers obtained in other embodiments all show that the obtained fiber diameters are uniform and all within 150 μm.

[0075] Figure 2 This is the infrared spectrum of the composite material with multiple functional groups obtained in Example 4. The 1710 cm⁻¹ is shown in the image. -1 The peak at 1600 cm⁻¹ is the characteristic absorption peak of the carboxyl group. -1 The peak at 1160 cm⁻¹ is the in-plane bending vibration peak of the NH group of the amide group. -1 The characteristic absorption peak of the sulfonic acid group is at 3030 cm⁻¹. -1 The broad peak at that point is the association peak of amino groups.

[0076] It is evident that the composite material contains multiple functional groups, and chitosan is cross-linked with SSMA. The resulting multifunctional composite material is a cross-linked complex of chitosan and SSMA, rather than a blend of the two. Detailed Implementation

[0077] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0078] The experimental data in the examples were measured using the following instruments and methods:

[0079] (1) The microstructure of the adsorption fiber (i.e., composite fiber) was observed using an EM-30AX+ scanning electron microscope from COXEM Corporation of South Korea.

[0080] (2) Determination of adsorption capacity.

[0081] Preparation of 1000 mg / L Pb 2+ Standard solution. The adsorption fibers (i.e., composite fibers) of the examples and comparative examples were respectively added to Pb solutions of the same concentration. 2+ In solution, adsorption was carried out at a certain temperature for 30 minutes. After adsorption was complete, the adsorbent was removed and dried for 12 hours. The adsorption amount was measured by a thermogravimetric analyzer. The adsorption amount was calculated using the following formula:

[0082]

[0083] In the formula, q is the adsorption capacity, in mg / g; m0 is the mass of the adsorbent before adsorption, in g; m r The final residual mass after thermogravimetric analysis is expressed in grams.

[0084] (3) The main preparation conditions and parameters of the maleic anhydride-alt-styrene copolymer (SMA) used in the examples: the molar ratio of maleic anhydride and styrene was 1:1, the reaction medium was isoamyl acetate, the initiator was azobisisobutyronitrile, and the reaction was carried out at 80°C for 5 h.

[0085] The main preparation conditions and parameters of the maleic anhydride-alt-α-methylstyrene copolymer (MASC) used in the examples are as follows: the molar ratio of maleic anhydride and α-methylstyrene is 1:1, the reaction medium is isoamyl acetate, the initiator is azobisisobutyronitrile, and the reaction is carried out at 80°C for 5 hours.

[0086] All other raw materials are commercially available.

[0087] In the following examples, unless otherwise specified, all concentration percentages are mass percentages.

[0088] The degree of deacetylation of the chitosan in the following examples is 92%.

[0089] Preparation of multifunctional heavy metal ion adsorption fibers (i.e., composite fibers)

[0090] Example 1

[0091] 5g of styrene-maleic anhydride copolymer (SMA) was added to 50g of 96% concentrated sulfuric acid and reacted at room temperature with stirring for 12h. The sulfonated product was washed several times with deionized water and ethanol alternately, and then dried under vacuum for 12h to obtain sulfonated styrene-maleic anhydride copolymer (SSMA) (polymer one).

[0092] SSMA was mixed with water to obtain a spinning solution, with the mass ratio of SSMA to water controlled at 3:10. The spinning solution was injected into a coagulation bath using a syringe pump. The coagulation bath was an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 5% and an acetic acid concentration of 5% (v / v). The volume ratio of the coagulation bath to the spinning solution was controlled at 1:10 when the spinning solution came into contact with the coagulation bath, and the mass ratio of SSMA to chitosan was 18:2.5. The spinning parameters were controlled as follows: spinneret diameter of 80 μm and injection rate of 0.05 mL / min.

[0093] After solidification at 25℃ for 30 minutes and drying, multifunctional heavy metal ion adsorption fibers (i.e., composite fibers, which are composite materials with multiple functional groups) were obtained. At 25℃, for Pb... 2+ The adsorption capacity of heavy metal ions is 512 mg / g.

[0094] Example 2

[0095] Take 5g of styrene-maleic anhydride copolymer, dissolve it in DMF, slowly add 50g of chlorosulfonic acid dropwise using a dropping funnel, react at 80℃ for 2h, and then distill under reduced pressure while hot to obtain the sulfonated product. Wash with ethanol to precipitate the precipitate, and dry under vacuum for 12h to obtain SSMA.

[0096] SSMA was mixed with water to obtain a spinning solution, with the mass ratio of SSMA to water controlled at 3:10. The spinning solution was injected into a coagulation bath using a syringe pump. The coagulation bath was an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 10% and an acetic acid concentration of 5% (v / v). The volume ratio of the coagulation bath to the spinning solution was controlled at 1:10, and the mass ratio of SSMA to chitosan was 18:5. The spinning parameters were controlled as follows: spinneret diameter of 80 μm and injection rate of 0.05 mL / min. After coagulation for 30 minutes, drying yielded multifunctional heavy metal ion adsorption fibers. At 25℃, the fibers were used to adsorb Pb... 2+ The adsorption capacity of heavy metal ions is 586 mg / g.

[0097] Example 3

[0098] Take 5g of styrene-maleic anhydride copolymer, pass SO3 gas into it, and obtain SSMA after 45 minutes.

[0099] SSMA was mixed with water to obtain a spinning solution, with the mass ratio of SSMA to water controlled at 1:5. The spinning solution was injected into a coagulation bath using a syringe pump. The coagulation bath was an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 20% and an acetic acid concentration of 5% (v / v). The volume ratio of the coagulation bath to the spinning solution was controlled at 1:10, and the mass ratio of SSMA to chitosan was 18:1. The spinning parameters were controlled as follows: spinneret diameter of 80 μm and injection rate of 0.05 mL / min. After coagulation for 30 minutes, drying yielded multifunctional heavy metal ion adsorption fibers. At 25℃, the fibers were used to adsorb Pb... 2+ The adsorption capacity of heavy metal ions is 625 mg / g.

[0100] Example 4

[0101] Take 5g of SSMA from Example 1. Mix SSMA with water to obtain a spinning solution, controlling the mass ratio of SSMA to water to be 1:5. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 30% and an acetic acid concentration of 5% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, and the mass ratio of SSMA to chitosan is 9:1. The spinning parameters are controlled as follows: spinneret diameter of 80μm and injection rate of 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25℃, for Pb 2+ The adsorption capacity of heavy metal ions is 701 mg / g.

[0102] Example 5

[0103] Take 5g of SSMA from Example 1. Mix SSMA with water to obtain a spinning solution, controlling the mass ratio of SSMA to water to be 1:10. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 30% and an acetic acid concentration of 5% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, the mass ratio of SSMA to chitosan is 18:4, and the spinning parameters are controlled as follows: spinneret diameter is 80μm, and injection rate is 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25℃, for Pb 2+ The adsorption capacity of heavy metal ions is 789 mg / g.

[0104] Example 6

[0105] Take 5g of SSMA from Example 1. Mix SSMA with water to obtain a spinning solution, controlling the mass ratio of SSMA to water to be 1:10. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 40% and an acetic acid concentration of 5% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, and the mass ratio of SSMA to chitosan is 18:100. The spinning parameters are controlled as follows: spinneret diameter of 80μm and injection rate of 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25℃, for Pb 2+ The adsorption capacity of heavy metal ions is 652 mg / g.

[0106] Example 7

[0107] 5g of maleic anhydride-alt-α-methylstyrene copolymer (MASC) was added to 50g of 96% concentrated sulfuric acid and reacted at room temperature with stirring for 12h. The sulfonated product was washed several times with deionized water and ethanol alternately, and then dried under vacuum for 12h to obtain sulfonated α-styrene-maleic anhydride copolymer (SMASC).

[0108] SMASC was mixed with water to obtain a spinning solution, with the mass ratio of SMASC to water controlled at 3:10. The spinning solution was injected into a coagulation bath using a syringe pump. The coagulation bath was an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 10% and an acetic acid concentration of 1% (v / v). The volume ratio of the coagulation bath to the spinning solution was controlled at 1:10, and the mass ratio of SMASC to chitosan was 2.7:2. The spinning parameters were controlled as follows: spinneret diameter of 80 μm and injection rate of 0.05 mL / min. After coagulation for 30 minutes, drying yielded multifunctional heavy metal ion adsorption fibers. At 5℃, the fibers were used to adsorb Pb... 2+ The adsorption capacity of heavy metal ions is 485 mg / g.

[0109] Example 8

[0110] Take 5g of SMASC from Example 7. Mix SMASC with water to obtain a spinning solution, controlling the mass ratio of SMASC to water to be 3:10. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 10% and an acetic acid concentration of 20% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, the mass ratio of SMASC to chitosan is 2.7:2, and the spinning parameters are controlled as follows: spinneret diameter is 80μm, and injection rate is 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25°C, for Pb 2+ The adsorption capacity of heavy metal ions is 614 mg / g.

[0111] Example 9

[0112] Take 5g of SMASC from Example 7. Mix SMASC with water to obtain a spinning solution, controlling the mass ratio of SMASC to water to be 3:10. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 10% and an acetic acid concentration of 50% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, and the mass ratio of SMASC to chitosan is 2.7:2. The spinning parameters are controlled as follows: spinneret diameter of 80μm and injection rate of 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 95℃, for Pb 2+The adsorption capacity of heavy metal ions is 452 mg / g.

[0113] Example 10

[0114] Multifunctional heavy metal ion adsorption fibers were prepared according to the method in Example 3, except that carboxymethyl chitosan (carboxylation degree greater than 60%) was used instead of chitosan.

[0115] It has been confirmed that this multifunctional heavy metal ion adsorption fiber effectively adsorbs Pb at 25°C. 2+ The amount of heavy metal ions adsorbed is similar to that in Example 3.

[0116] Example 11

[0117] Multifunctional heavy metal ion adsorption fibers were prepared according to the method of Example 1, except that fuming nitric acid was used instead of concentrated sulfuric acid in Example 1.

[0118] The nitrated modified multifunctional heavy metal ion adsorption fiber was prepared by the following method: 5g of styrene-maleic anhydride copolymer was added to 30g of fuming nitric acid with a mass concentration of 98%, and reacted at 0℃ for 3h. The product was washed several times with deionized water and ethanol alternately, and then vacuum dried for 12h to obtain nitrated styrene-maleic anhydride copolymer (NSMA).

[0119] It has been confirmed that this multifunctional heavy metal ion adsorption fiber effectively adsorbs Pb at 25°C. 2+ The adsorption capacity of heavy metal ions is 485 mg / g.

[0120] Comparative Example 1

[0121] Take 5g of SMA from Example 1. Mix SMA with acetone to obtain a spinning solution, controlling the mass ratio of SMA to water to be 1:10. Inject the spinning solution into a coagulation bath using an injection pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 30% and an acetic acid concentration of 5% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled to be 1:10, the mass ratio of SMA to chitosan is 18:4, and the spinning parameters are controlled as follows: spinneret diameter is 80μm, and injection rate is 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25℃, for Pb 2+ The adsorption capacity of heavy metal ions is 400 mg / g.

[0122] Comparative Example 2

[0123] Take 5g of SMA from Example 1. Add SMA to an aqueous solution of sodium hydroxide and heat at 90°C for 8 hours until it becomes a transparent spinning solution. The mass ratio of SMA to sodium hydroxide is 5:1, and the mass ratio of SMA to water is controlled at 1:10. Inject the spinning solution into a coagulation bath using a syringe pump. The coagulation bath is an aqueous solution of chitosan and acetic acid, with a chitosan concentration of 30% and an acetic acid concentration of 5% (v / v). When the spinning solution is in contact with the coagulation bath, the volume ratio of the coagulation bath to the spinning solution is controlled at 1:10, the mass ratio of SMA to chitosan is 18:4, and the spinning parameters are controlled as follows: spinneret diameter is 80μm, and injection rate is 0.05mL / min. After coagulation for 30 minutes, dry to obtain multifunctional heavy metal ion adsorption fibers. At 25°C, for Pb 2+ The adsorption capacity of heavy metal ions is 360 mg / g.

[0124] Detection example

[0125] Elemental analysis of C, H, O, and N in the composite fibers confirmed that the total content of carboxyl, amino, amide, hydroxyl, and sulfonic acid or nitro groups in each g of the composite fibers in the above examples was in the range of 2-10 mmol.

[0126] Table 1

[0127] Serial Number Chitosan (g) SSMA(g) Adsorption capacity q (mg / g) Example 1 0.25 1.8 512 Example 2 0.5 1.8 586 Example 3 1 1.8 625 Example 4 2 1.8 701 Example 5 4 1.8 789 Example 6 10 1.8 652 Serial Number Chitosan (g) / SMASC (g) Concentration of acetic acid aqueous solution (%) Adsorption capacity q (mg / g) Example 7 2 / 2.7 1 485 Example 8 2 / 2.7 20 614 Example 9 2 / 2.7 50 452

[0128] As can be seen from the above embodiments, the present invention has prepared a multifunctional heavy metal ion adsorption fiber. Unlike the grafting or cross-linking modification of natural polymers by small molecules, the present invention selects synthetic polymers to modify natural polymers to prepare a multifunctional heavy metal ion adsorption fiber with a cross-linking structure. As a composite fiber, it has a larger adsorption specific surface area and a better adsorption effect.

[0129] A comparison of the examples and comparative examples shows that, in the case of composite fibers, the multifunctional heavy metal ion adsorption fiber of the present invention, compared with the composite fiber in the comparative example, has a higher adsorption capacity for Pb compared to the composite fiber in the comparative example. 2+ The adsorption capacity of heavy metal ions increased significantly. This advantage is likely due to the synergistic adsorption effect between different functional groups, which effectively enhances the adsorption capacity of heavy metal ions.

[0130] As can be seen from Examples 7, 9 and other examples, the composite fiber of the present invention is a heavy metal ion adsorption fiber that can be used in a wide temperature range, and can maintain a good adsorption capacity for heavy metal ions at both below room temperature and at higher temperatures.

[0131] A comparison of Examples 4 and 5 with Examples 1 and 2 shows that, within the preferred ratio range of chitosan and SMA in this invention, the resulting composite fibers are effective against Pb. 2+Heavy metal ions have a higher adsorption capacity.

[0132] As can be seen from the comparison between Example 8 and Examples 7 and 9, under the preferred concentration range of the acetic acid aqueous solution of the present invention, the obtained composite fibers have a better effect on Pb. 2+ Heavy metal ions have a higher adsorption capacity.

[0133] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0134] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0135] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0136] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0137] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0138] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A composite material having multiple functional groups, comprising at least two groups including carboxyl, amino, amide and hydroxyl groups, and at least one group including sulfonic acid group and nitro group; The composite material contains a crosslinked complex of polymer one and polymer two, wherein polymer one is a carbon chain polymer and contains at least one group including sulfonic acid group and nitro group; The polymer 2 is at least one of chitosan and its derivatives, and chitin and its derivatives.

2. The composite material according to claim 1, characterized in that: The polymer is derived from at least one copolymer raw material selected from sulfonated and / or nitrated copolymers of the following: acid anhydride copolymers; preferably, The anhydride copolymer is selected from at least one of maleic anhydride copolymer, itaconic anhydride copolymer, and citraconic anhydride copolymer.

3. The composite material according to claim 2, characterized in that: The structure of the copolymer raw material is shown in formula (I), containing structural unit A and structural unit B; Where x, y, and z are all natural numbers, x>1, y+z≥0, preferably at least one of y and z is 0; more preferably y=z=0; The structural unit A is derived from at least one of maleic anhydride, itaconic anhydride, and citraconic anhydride, preferably maleic anhydride; The structural unit B is derived from a monomer containing isolated carbon-carbon double bonds, preferably a monomer having the formula (II): The Y1 group is one of H, —CH3, —CH2CH3, and —CH(CH3)2; the Y2 group is an alkyl group with 2 to 8 carbon atoms. One of them; the alkyl group having 2 to 8 carbon atoms is preferably one or more of —CH2CH3, —CH2CH2CH3, —CH(CH3)2, —CH2(CH3)CH2CH3, and —CH2CH2CH2CH3; Preferably, the sulfonic acid group and nitro group in the composite material are each connected to the Y2 group of structural unit B.

4. The composite material according to claim 1, characterized in that: The polymer is derived from at least one copolymer raw material selected from sulfonated and / or nitrated copolymers of the following: At least one of the following: maleic anhydride-styrene alternating copolymer, maleic anhydride-α-methylstyrene alternating copolymer, maleic anhydride-vinyl formate copolymer, maleic anhydride-vinyl acetate copolymer, maleic anhydride-vinyl propionate copolymer, maleic anhydride-vinyl butyrate copolymer, and maleic anhydride-acrylic acid copolymer, preferably at least one of maleic anhydride-styrene alternating copolymer and maleic anhydride-α-methylstyrene alternating copolymer; and / or, The polymer 2 is selected from at least one of chitosan, chitin, carboxymethyl chitin, acylated chitosan, alkylated chitosan, and quaternized chitosan; preferably at least one of chitosan, acylated chitosan, carboxylated chitosan, and quaternized chitosan.

5. The composite material according to claim 1, characterized in that: The polymer one and polymer two are separated by amide groups. Crosslinking; and / or, The weight ratio of polymer one to polymer two in the composite material is 1:(1-10), preferably 1:(1-2.5); And / or, the total content of carboxyl, amino, amide, hydroxyl, sulfonic acid and nitro groups in each g of the composite material is 2-10 mmol.

6. The composite material according to any one of claims 1-5, characterized in that: The composite material is a composite fiber; preferably, The diameter of the composite fiber is less than 300 μm, more preferably less than 200 μm; and / or, preferably, The composite fiber was prepared by solution spinning. More preferably, the solution spinning method uses a coagulation bath to form fibers from the spinning solution, wherein the spinning solution is a solution containing polymer one, and the coagulation bath is a solution containing polymer two.

7. A method for preparing a composite material with multiple functional groups, preferably the method for preparing a composite material with multiple functional groups according to any one of claims 1-6, comprising: A copolymer raw material containing at least one acid anhydride copolymer is subjected to sulfonation modification and / or nitration modification to obtain polymer one; A first solution containing polymer one and a second solution containing polymer two are reacted to remove the solvent, thereby obtaining the composite material with multiple functional groups. The polymer 2 is at least one of chitosan and its derivatives, and chitin and its derivatives.

8. The preparation method according to claim 7, characterized in that: The reaction between the first solution and the second solution is via solution spinning; preferably, The solution spinning method uses a coagulation bath to make the spinning solution into fibers. The first solution is used as the spinning solution, and the second solution is used as the coagulation bath. The spinning solution comes into contact with the coagulation bath to obtain gel fibers, which are then dried to obtain fibrous composite materials. More preferably, the conditions for solution spinning include: The diameter of the spinneret is 0.1–400 μm, preferably 0.1–300 μm, more preferably 0.1–200 μm; and / or, the coagulation bath temperature is 10°C–100°C, preferably 20°C–100°C, more preferably 25°C–90°C.

9. The preparation method according to claim 7 or 8, characterized in that: The sulfonation modification method includes contacting the copolymer raw material with a sulfonating agent; preferably, the sulfonating agent is at least one selected from concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid, and SO3 gas; and / or, The nitration modification method includes contacting the copolymer raw material with a nitrifying agent, preferably, the nitrifying agent is fuming nitric acid.

10. The preparation method according to claim 7 or 8, characterized in that: The mass ratio of polymer one to polymer two is no greater than 1:0.1, preferably 1:(0.5-10), more preferably 1:(1-5); and / or, The anhydride copolymer is selected from at least one of maleic anhydride copolymer, itaconic anhydride copolymer, and citraconic anhydride copolymer.

11. The preparation method according to claim 7 or 8, characterized in that: The first solvent in the first solution is water and / or an organic solvent capable of dissolving the polymer one, preferably, the organic solvent is selected from at least one of acetone, tetrahydrofuran, and N,N-dimethylformamide; and / or, The mass ratio of the polymer to the first solvent in the first solution is (1-50):100, more preferably (10-30):

100.

12. The preparation method according to claim 7 or 8, characterized in that: The mass ratio of polymer II to the second solvent in the second solution is (1-100):100, preferably (1-50):100, more preferably (5-30):100; and / or, The second solvent is a mixed solvent capable of dissolving polymer II. Preferably, the mixed solvent is at least one of aqueous acetic acid, aqueous sulfuric acid, and aqueous hydrochloric acid. More preferably, the volume ratio of solute to water in the mixed solvent is (1-100):100, preferably (1-4):100, and more preferably (5-20):

100.

13. The composite material with multifunctional groups according to any one of claims 1-6 or the composite material with multifunctional groups obtained by the preparation method according to any one of claims 7-12 is used in the field of water treatment, preferably for metal ion adsorption, and more preferably for heavy metal ion adsorption.

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