Composite adsorption material based on modified biomass charcoal and degradable polymer as well as preparation method and application of composite adsorption material

Abstract

The invention provides a composite adsorption material based on modified biomass charcoal and a degradable polymer and a preparation method and application thereof, and relates to the technical field of environment-friendly adsorption materials, the composite adsorption material comprises the following components: modified biomass charcoal, polylactic acid, a cross-linking agent and a compatibilizer; wherein biomass is sequentially subjected to organic acid activation, carbonization and magnetic composite nanoparticle loading modification treatment, and the modified biomass charcoal is obtained. The composite adsorption material based on the modified biomass charcoal and the degradable polymer, provided by the invention, has high adsorption capacity and biodegradability.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly adsorption materials, and in particular to a composite adsorption material based on modified biochar and a degradable polymer, and a preparation method and application thereof. Background Art

[0002] With the growing demand for environmental pollution control, adsorption materials play an important role in the treatment of heavy metals and organic pollutants in water bodies. Activated carbon has long been used as a typical adsorption material for industrial wastewater treatment due to its well-developed porous structure and large specific surface area. Commercially available activated carbon is mainly prepared by physical or chemical activation of biomass raw materials. Its adsorption performance is significantly affected by factors such as raw material type, activation process and surface modification. 2 +) adsorption, the adsorption capacity of traditional activated carbon materials usually does not exceed 80mg / g. In the regeneration process after use, activated carbon needs to be treated by high-temperature pyrolysis or chemical elution, which not only consumes a lot of energy but also the adsorption capacity will gradually decrease. In addition, the production of activated carbon depends on non-renewable resources such as wood and coal. Therefore, traditional activated carbon adsorption materials have low adsorption capacity (such as commercial activated carbon for Pb 2+ Adsorption capacity ≤80mg / g), high regeneration cost, non-renewable raw materials and other problems.

[0003] Polymer-based adsorbents are an emerging alternative, forming a three-dimensional network structure through the polymerization of functional monomers to achieve selective adsorption of specific pollutants. Polyvinyl alcohol (PVA) gel, a typical example, achieves adsorption through the coordination of hydroxyl groups with heavy metal ions. However, insufficient cross-linking results in low mechanical strength and is prone to structural collapse in dynamic water flow. Furthermore, polymer-based adsorbents lack degradation properties, making them susceptible to secondary pollution.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] One of the objectives of the present invention is to provide a composite adsorbent material based on modified biochar and a degradable polymer to address at least one of the technical problems existing in the prior art. The composite adsorbent material based on modified biochar and a degradable polymer provided by the present invention combines high adsorption capacity with biodegradability.

[0006] A second object of the present invention is to provide a method for preparing a composite adsorption material based on modified biochar and a degradable polymer.

[0007] The third object of the present invention is to provide a composite adsorption material based on modified biochar and a degradable polymer, or the application of the composite adsorption material based on modified biochar and a degradable polymer prepared by the preparation method in industrial pollution control.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0009] In a first aspect, the present invention provides a composite adsorption material based on modified biochar and a degradable polymer, comprising the following components: modified biochar, polylactic acid, a cross-linking agent, and a compatibilizer;

[0010] The biomass is sequentially subjected to organic acid activation, carbonization and magnetic composite nanoparticle loading modification treatments to obtain the modified biomass carbon.

[0011] Further, the organic acid includes acetic acid and / or benzenesulfonic acid;

[0012] And / or, the magnetic composite nanoparticles include: one or more of Fe3O4@Au, Fe3O4@SiO2 and Fe3O4 / TiO2;

[0013] And / or, the particle size of the Fe3O4 / TiO2 is 40-100 nm, the particle size of the Fe3O4@Au is 40-90 nm, and the particle size of the Fe3O4@SiO2 is 40-95 nm.

[0014] Furthermore, in the modified biochar, the loading amount of the magnetic composite nanoparticles is 5wt%-10wt%.

[0015] Furthermore, the biomass raw materials include corn stalks and / or rice husks;

[0016] and / or, the biomass has a particle size of 100 to 200 mesh;

[0017] and / or, the polylactic acid has an Mw of 18,000-24,000;

[0018] and / or, the cross-linking agent comprises epichlorohydrin and / or methacrylic acid;

[0019] And / or, the compatibilizer includes maleic anhydride grafted polylactic acid and / or ethylene glycol carbonate.

[0020] Furthermore, the composite adsorption material comprises the following components in parts by mass:

[0021] 40 to 60 parts of modified biochar, 30 to 40 parts of polylactic acid, 5 to 8 parts of a cross-linking agent and 5 to 10 parts of a compatibilizer.

[0022] In a second aspect, the present invention provides a method for preparing a composite adsorption material based on modified biochar and a degradable polymer, comprising the following steps:

[0023] Mix the modified biomass charcoal, polylactic acid, crosslinking agent and compatibilizer in a formula amount to obtain the composite adsorption material.

[0024] Further, the preparation process of the modified biomass charcoal comprises:

[0025] (a) mixing the biomass with the organic acid and then carbonizing to obtain an organic acid activated carbon;

[0026] (b) loading the magnetic composite nanoparticles on the organic acid activated carbon;

[0027] And / or, the concentration of the organic acid is 0.4-0.6 mol / L;

[0028] And / or, in step (a), the temperature of the mixing process is 70-90℃, and the stirring time is 1-3h;

[0029] And / or, in step (a), the carbonization temperature is 550-650℃, and the carbonization time is 0.5-1.5h;

[0030] And / or, in step (b), the magnetic composite nanoparticles are loaded on the organic acid activated carbon by using a hydrothermal method, the reaction temperature is 110-130℃, and the reaction time is 5-7h.

[0031] Further, the Fe3O4 nanoparticles are used as core materials, and the Fe3O4 nanoparticles are wrapped with a coating layer outside;

[0032] And / or, the coating layer comprises one or more of Au, SiO2 and TiO2.

[0033] Further, the mixing process of the modified biomass charcoal, polylactic acid, crosslinking agent and compatibilizer comprises: melt blending at 180-200℃;

[0034] And / or, after melt blending, sequentially perform hot pressing and cutting treatment;

[0035] And / or, the pressure of the hot pressing is 9-11MPa, the temperature is 160-180℃, and the time is 8-12min.

[0036] In a third aspect, the application provides an application of a composite adsorption material based on modified biomass charcoal and degradable polymer or prepared by the preparation method in industrial pollution control.

[0037] Compared with the prior art, the application has the following beneficial effects:

[0038] The composite adsorption material based on modified biochar and degradable polymer provided by the present invention adopts organic acid to modify biochar, which, on the one hand, enhances the biodegradability of the material, and on the other hand, adopts organic acid as modification and pore expansion template agent, thereby improving the porosity and BET specific surface area of ​​biochar, and at the same time increasing the surface active sites of biochar, which is conducive to the attachment of pollutants on the surface of the adsorption material and improving the adsorption efficiency of pollutants by the material; the present invention loads magnetic composite nanoparticles on biochar, which can promote the catalytic oxidation of pollutants after the material completes the adsorption of pollutants to achieve the purpose of removing pollutants; the present invention uses degradable polylactic acid as a carrier, which improves the mechanical strength and recycling convenience of the material; in the present invention, the crosslinking agent and the compatibilizer optimize the interface bonding to prevent structural collapse during the adsorption-desorption process. The present invention solves the technical problems of low adsorption capacity, poor mechanical strength and insufficient degradation performance of adsorption materials in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 This is the SEM image of Fe3O4 / TiO2 in Example 1 of the present invention (particle size is 40-60nm);

[0041] Figure 2 This is a TEM image of Fe3O4 / TiO2 in Example 1 of the present invention, from which the distribution of magnetic particles in the material can be seen. DETAILED DESCRIPTION

[0042] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, the use of "or" means "and / or" unless otherwise stated. In addition, the use of the term "including" and other forms is non-limiting.

[0043] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] The first aspect of the present invention provides a composite adsorption material based on modified biochar and a degradable polymer, comprising the following components: modified biochar, polylactic acid (PLA), a cross-linking agent, and a compatibilizer;

[0045] The biomass is sequentially subjected to organic acid activation, carbonization and magnetic composite nanoparticle loading modification treatments to obtain the modified biomass carbon.

[0046] In the present invention, PLA-based degradable polymer is used as a carrier to improve the mechanical strength and recycling convenience (magnetic separation) of the material.

[0047] In some preferred embodiments, the organic acid comprises acetic acid and / or benzenesulfonic acid.

[0048] In the present invention, organic acids such as acetic acid and benzenesulfonic acid are used for activation to improve the porosity of biochar loaded with magnetic composite nanoparticles (BET specific surface area ≥ 800m 2 / g) and surface active sites, which are conducive to the attachment of pollutants on the surface of the adsorption material.

[0049] And / or, the magnetic composite nanoparticles include one or more of Fe3O4@Au, Fe3O4@SiO2 and Fe3O4 / TiO2.

[0050] In the present invention, the nanoparticles Fe3O4@Au (gold-coated iron), Fe3O4@SiO2 (silicon dioxide-coated), and multi-component composite particles (such as Fe3O4 / TiO2) with magnetic and photocatalytic properties are all core-shell structured nanoparticles. The core-shell structured nanoparticles are prepared by the sol-gel method, have magnetic and catalytic activity, and can promote the catalytic oxidation of pollutants after the material completes the adsorption of pollutants to achieve the purpose of removing pollutants.

[0051] And / or, the particle size of the Fe3O4 / TiO2 is 40-100 nm, the particle size of the Fe3O4@Au is 40-90 nm, and the particle size of the Fe3O4@SiO2 is 40-95 nm.

[0052] In some preferred embodiments, the loading amount of the magnetic composite nanoparticles in the modified biochar is 5wt%-10wt%, for example, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc.;

[0053] In some preferred embodiments, the biomass raw material includes corn stalks and / or rice husks.

[0054] In the present application, corn stalks and / or rice husks are used as biomass raw materials, which are not only abundant and renewable, but also can effectively reduce the accumulation of agricultural waste, avoiding environmental pollution caused by burning or piling. In addition, corn stalks and rice husks are usually by-products of agricultural production, and the cost of obtaining them is relatively low. At the same time, converting these wastes into useful biomass products can reduce the waste disposal costs of farmers and agricultural enterprises.

[0055] And / or, the particle size of the biomass is 100-200 mesh, for example, it can be 100 mesh, 150 mesh, 200 mesh, etc.

[0056] And / or, the Mw of the polylactic acid is 18,000-24,000.

[0057] And / or, the crosslinking agent includes epichlorohydrin and / or methacrylic acid.

[0058] And / or, the compatibilizer includes maleic anhydride grafted polylactic acid and / or ethylene glycol carbonate.

[0059] In some preferred embodiments, the composite adsorption material includes the following components by mass fraction:

[0060] 40-60 parts of modified biomass charcoal, 30-40 parts of polylactic acid, 5-8 parts of crosslinking agent, and 5-10 parts of compatibilizer.

[0061] In the composite adsorption material, the addition amount of modified biomass charcoal is 40-60 parts, for example, it can be 40 parts, 50 parts, 60 parts, etc.

[0062] In the composite adsorption material, the addition amount of polylactic acid is 30-40 parts, for example, it can be 30 parts, 35 parts, 40 parts, etc.

[0063] In the composite adsorption material, the addition amount of crosslinking agent is 5-8 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, etc.

[0064] In the composite adsorption material, the addition amount of compatibilizer is 5-10 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0065] The second aspect of the present application provides a preparation method of a composite adsorption material based on modified biomass charcoal and degradable polymer, which includes the following steps:

[0066] Mixing the formula amount of modified biomass charcoal, polylactic acid, crosslinking agent and compatibilizer to obtain the composite adsorption material.

[0067] In some preferred embodiments, the preparation process of the modified biomass charcoal includes:

[0068] (a) mixing biomass with an organic acid and carbonizing the mixture to obtain organic acid activated carbon;

[0069] (b) loading the magnetic composite nanoparticles on the organic acid activated carbon;

[0070] And / or, the concentration of the organic acid is 0.4-0.6 mol / L, for example, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, etc.;

[0071] And / or, in step (a), the temperature of the mixing process is 70-90° C., for example, 70° C., 80° C., 90° C., etc.; the stirring time is 1-3 h, for example, 1 h, 2 h, 3 h, etc.;

[0072] And / or, in step (a), the carbonization temperature is 550-650° C., for example, 550° C., 600° C., 650° C., etc.; the carbonization time is 0.5-1.5 h, for example, 0.5 h, 1 h, 1.5 h, etc.;

[0073] And / or, in step (b), the magnetic composite nanoparticles are loaded on the organic acid activated carbon by a hydrothermal method, the reaction temperature is 110-130°C, for example, it can be 110°C, 120°C, 130°C, etc.; the reaction time is 5-7h, for example, it can be 5h, 6h, 7h, etc.

[0074] In some preferred embodiments, Fe3O4 nanoparticles are used as the core material, and the outside of the Fe3O4 nanoparticles is coated with a coating layer;

[0075] And / or, the coating layer includes one or more of Au, SiO2 and TiO2.

[0076] In the present invention, the preparation of Fe3O4 nanoparticles comprises the following steps:

[0077] Fe3O4 nanoparticles were prepared by hydrothermal method: iron salts (such as FeCl2 and FeCl3) were dissolved in water, Fe 3+ A concentration of 0.1 mol / L is then added to an alkaline solution (such as NaOH or NH4OH) to precipitate Fe3O4 nanoparticles. The size and morphology of the nanoparticles can be adjusted by controlling the pH (12-14), temperature (60-70°C), and reaction time (6-8 hours). After the reaction is complete, the nanoparticles are collected by centrifugation or filtration and washed with water and an organic solvent to remove impurities.

[0078] Among them, the preparation process of Fe3O4@SiO2 (silicon dioxide coated) is:

[0079] a. Fe3O4 nanoparticles were prepared by the hydrothermal method described above;

[0080] b. The Fe3O4 nanoparticles were dispersed in an ethanol-water mixed solvent in a volume ratio of 1:1, and ultrasonic treatment was performed to form a uniform dispersion. A silicon source such as TEOS and sodium metasilicate was slowly added dropwise while stirring. An organic base such as tetramethylammonium hydroxide and tetraethylammonium hydroxide was then added to catalyze the polycondensation.

[0081] c. After the solution forms a gel, it is placed in a reaction condition at 100-150°C for 36-72 hours. The crude product is washed with water three times and dried at 100°C for 10 hours to obtain core-shell structured composite nanoparticles.

[0082] Among them, the preparation process of Fe3O4@Au (gold-coated iron) is:

[0083] a. Fe3O4 nanoparticles were prepared by the hydrothermal method described above;

[0084] b. Fe3O4 nanoparticles were dispersed in a 1:1 ethanol-water mixed solvent, and ultrasonic treatment was performed to form a uniform dispersion. HAuCl4 and other organic bases were slowly added dropwise while stirring. Then, strong organic bases such as sodium citrate (Na3C6H5O7), tetramethylammonium hydroxide, and tetraethylammonium hydroxide were added for reduction and condensation.

[0085] c. After the above solution forms a gel, it is placed at 100-150°C for 36-72 hours. The crude product is washed three times with water and dried at 100°C for 10 hours to obtain core-shell composite nanoparticles.

[0086] Among them, the preparation process of multi-component composite particles (Fe3O4 / TiO2) is:

[0087] a. Fe3O4 nanoparticles were prepared by the hydrothermal method described above;

[0088] b. The Fe3O4 nanoparticles were dispersed in an ethanol-water mixed solvent in a volume ratio of 1:1, and ultrasonic treatment was performed to form a uniform dispersion. A titanium source such as tetraethyl titanate and titanium tetrachloride was slowly added dropwise while stirring. An organic base such as tetramethylammonium hydroxide and tetraethylammonium hydroxide was then added to catalyze the polycondensation.

[0089] c. After the above solution forms a gel, it is placed at 100-150°C for 36-72 hours. The crude product is washed three times with water and dried at 100°C for 10 hours to obtain core-shell composite nanoparticles.

[0090] In some preferred embodiments, the mixing process of the modified biochar, polylactic acid, crosslinking agent and compatibilizer includes: melt blending at 180-200° C., for example, 180° C., 190° C., 200° C., etc.;

[0091] and / or, melt blending followed by hot pressing and cutting;

[0092] And / or, the hot pressing pressure is 9-11 MPa, for example, 9 MPa, 10 MPa, etc.; the temperature is 160-180°C, for example, 160°C, 170°C, 180°C, etc.; the time is 8-12 min, for example, 8 min, 9 min, 10 min, 11 min, 12 min, etc.

[0093] In the optional scheme of the present invention, preferably, the preparation method of the composite adsorption material based on modified biochar and degradable polymer comprises the following steps:

[0094] Step 1: Mix the modified biochar, PLA particles, cross-linking agent and compatibilizer in proportion;

[0095] Step 2: melt blending using a twin-screw extruder at a temperature of 180-200° C. and a rotation speed of 200 rpm;

[0096] Step 3: hot pressing (pressure 10 MPa, temperature 170°C, time 10 min), and then cutting into particles;

[0097] Among them, the process of biochar modification is:

[0098] (1) The raw materials were crushed into 100-200 mesh, immersed in 0.5 mol / L organic acid solution such as acetic acid and benzenesulfonic acid (solid-to-liquid ratio 1:10), and stirred at 80°C for 2 h;

[0099] (2) After washing and drying, carbonization was performed at 600°C in a nitrogen atmosphere for 1 h to obtain organic acid activated carbon;

[0100] (3) The magnetic composite nanoparticles were loaded on the carbon surface by a hydrothermal method with a reaction temperature of 120°C and a reaction time of 6 h to obtain modified biomass carbon.

[0101] The third aspect of the present invention provides a composite adsorption material based on modified biochar and a degradable polymer, or the use of the composite adsorption material based on modified biochar and a degradable polymer prepared by the preparation method in industrial pollution control.

[0102] The present invention has developed an environmentally friendly material with high adsorption capacity (target: heavy metal ion adsorption capacity ≥150mg / g), biodegradability and low cost. By modifying biomass carbon and compounding it with degradable polymer, it has high adsorption capacity (Pb 2+ It has the characteristics of adsorption capacity ≥150mg / g), visible light catalysis, magnetic easy recovery and biodegradability, and is suitable for industrial pollution control. The cost is more than 40% lower than that of traditional materials.

[0103] The composite adsorption material based on modified biochar and degradable polymer provided by the present invention is a high-adsorption performance environmentally friendly material composed of modified biochar and degradable polymer prepared from agricultural and forestry waste as raw materials. It is suitable for industrial wastewater treatment, heavy metal ion removal and organic pollutant adsorption; it can be used in the semiconductor industry. For example, in the etching and cleaning process of wafers, the chemicals used may contain heavy metal ions such as copper, aluminum, chromium, nickel, silver, cadmium, etc., which will cause serious harm to the ecosystem and human health after entering the environment.

[0104] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0105] In the examples and comparative examples of the present invention, the polylactic acid used was (NatureWorks, USA, 4032D), epichlorohydrin (Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No. 106-89-8), and maleic anhydride grafted polylactic acid PLA (Xi'an Qiyue Biological, PLA-g-St / MAH).

[0106] Example 1

[0107] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer, which includes the following components in parts by mass:

[0108] 50 parts of modified biochar, 35 parts of polylactic acid, 7 parts of epichlorohydrin and 8 parts of maleic anhydride grafted polylactic acid (PLA); wherein the Fe3O4 / TiO2 loading in the modified biochar is 8 wt%;

[0109] The preparation method of the composite adsorption material based on modified biochar and degradable polymer comprises the following steps:

[0110] Step 1: Mixing modified biochar, PLA particles, epichlorohydrin and maleic anhydride grafted polylactic acid in proportion;

[0111] Step 2: melt blending using a twin-screw extruder at a temperature of 190° C. and a rotation speed of 200 rpm;

[0112] Step 3: hot pressing (pressure 10 MPa, temperature 170°C, time 10 min), and then cutting into 3 mm particles;

[0113] Among them, the process of biochar modification is:

[0114] (1) The raw material (rice husk) was crushed to 100-200 mesh, immersed in 0.5 mol / L acetic acid solution (solid-liquid ratio 1:10), and stirred at 80°C for 2 h;

[0115] (2) After washing and drying, carbonization was performed at 600°C in a nitrogen atmosphere for 1 h to obtain organic acid activated carbon;

[0116] (3) Fe3O4 / TiO2 was loaded on the carbon surface by a hydrothermal method with a reaction temperature of 120℃ and a reaction time of 6h to obtain modified biochar.

[0117] Among them, the preparation process of Fe3O4 / TiO2 is as follows:

[0118] Among them, multi-component composite particles The preparation process is:

[0119] a. Preparation of Fe3O4 nanoparticles by hydrothermal method: dissolve iron salts (such as FeCl2 and FeCl3) in water, Fe 3+ A concentration of 0.1 mol / L was added, followed by the addition of an alkaline solution (NaOH) to precipitate Fe3O4 nanoparticles. The pH was controlled at 13, the temperature at 65°C, and the reaction time was 7 hours. After the reaction was complete, the nanoparticles were collected by filtration and washed with water and an organic solvent to remove impurities.

[0120] b 250g Fe3O4 nanoparticles were dispersed in 100mL ethanol - water volume ratio 1: 1 mixed solvent, ultrasonic treatment to form a uniform dispersion, slowly added dropwise 40g of titanium source tetraethyl titanate, while maintaining stirring, and then added 10g of organic base tetramethylammonium hydroxide catalyzed polycondensation;

[0121] c. After the solution forms a gel, it is reacted at 125°C for 48 hours. The crude product is washed with water three times and dried at 100°C for 10 hours to obtain core-shell composite nanoparticles with a particle size of 40-60 nm.

[0122] Example 2

[0123] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer, which includes the following components in parts by mass:

[0124] 40 parts of modified biochar, 40 parts of polylactic acid, 5 parts of epichlorohydrin and 10 parts of maleic anhydride grafted polylactic acid PLA;

[0125] Among them, the Fe3O4 / TiO2 loading in the modified biochar is 5wt%;

[0126] The preparation method of the composite adsorption material based on modified biochar and degradable polymer is consistent with that in Example 1.

[0127] Example 3

[0128] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer, which includes the following components in parts by mass:

[0129] 60 parts of modified biochar, 30 parts of polylactic acid, 8 parts of epichlorohydrin and 5 parts of maleic anhydride grafted polylactic acid PLA;

[0130] Among them, the Fe3O4 / TiO2 loading in the modified biochar is 10wt%;

[0131] The preparation method of the composite adsorption material based on modified biochar and degradable polymer is consistent with that in Example 1.

[0132] Example 4

[0133] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer. The difference from Example 1 is that in the modified biochar, Fe3O4@Au is loaded on the biochar;

[0134] The preparation process of Fe3O4@Au is as follows:

[0135] a. consistent with step a in Example 1;

[0136] b. 250 g of Fe3O4 nanoparticles were dispersed in 100 mL of an ethanol-water mixed solvent in a volume ratio of 1:1, and ultrasonically treated to form a uniform dispersion. 40 g of chloroauric acid (HAuCl4) was slowly added dropwise while stirring, and then 10 g of an organic base, sodium citrate (Na3C6H5O7), was added for reduction and polycondensation.

[0137] c. After the solution forms a gel, it is reacted at 125°C for 48 hours. The crude product is washed three times with water and dried at 100°C for 10 hours to obtain core-shell composite nanoparticles with a particle size of 45-70 nm.

[0138] The rest is consistent with Example 1.

[0139] Example 5

[0140] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer. The difference from Example 1 is that in the modified biochar, Fe3O4@SiO2 is loaded on the biochar;

[0141] The preparation process of Fe3O4@SiO2 is as follows:

[0142] a. consistent with step a in Example 1;

[0143] b 250g Fe3O4 nanoparticles were dispersed in 100mL ethanol - water volume ratio of 1: 1 mixed solvent, ultrasonic treatment to form a uniform dispersion, 40g of silicon source TEOS was slowly added dropwise while stirring, and then 10g of organic base tetramethylammonium hydroxide was added to catalyze the polycondensation;

[0144] c. After the solution forms a gel, it is reacted at 125°C for 48 hours. The crude product is washed with water three times and dried at 100°C for 10 hours to obtain core-shell composite nanoparticles with a particle size of 42-65 nm.

[0145] Example 6 (low-cost ratio)

[0146] This embodiment provides a composite adsorption material based on modified biochar and degradable polymer. The difference from Example 1 is: 40 parts of modified biochar, 40 parts of PLA, 5 parts of epichlorohydrin, and 5 parts of maleic anhydride-grafted PLA;

[0147] Corn straw was used as biomass raw material, and benzenesulfonic acid was used as organic acid;

[0148] The rest is consistent with Example 1.

[0149] Example 7

[0150] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer. The difference from Example 1 is:

[0151] 39 parts of modified biochar, 41 parts of polylactic acid, 4 parts of epichlorohydrin and 11 parts of maleic anhydride grafted PLA; wherein the Fe3O4 / TiO2 loading in the modified biochar is 4wt%;

[0152] The rest is consistent with Example 1.

[0153] Example 8

[0154] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer, which includes the following components in parts by mass:

[0155] 61 parts of modified biochar, 29 parts of polylactic acid, 9 parts of epichlorohydrin and 4 parts of maleic anhydride grafted PLA; wherein the Fe3O4 / TiO2 loading in the modified biochar is 11wt%;

[0156] The rest is consistent with Example 1.

[0157] Example 9

[0158] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer. The difference from Example 1 is:

[0159] In the preparation process of the composite adsorbent material: in step 2, a twin-screw extruder is used for melt blending at a temperature of 180°C and a speed of 200 rpm; in step 3, hot pressing is performed (pressure 9 MPa, temperature 180°C, time 8 min), and then cut into 3 mm particles;

[0160] Among them, the process of biochar modification is:

[0161] (1) The raw material (rice husk) was crushed to 100 mesh, immersed in 0.4 mol / L acetic acid solution (solid-to-liquid ratio 1:10), and stirred at 70°C for 3 h;

[0162] (2) After washing and drying, carbonization was performed at 550°C in a nitrogen atmosphere for 1.5 h to obtain organic acid activated carbon;

[0163] (3) Fe3O4 / TiO2 was loaded on the carbon surface by a hydrothermal method with a reaction temperature of 110℃ and a reaction time of 7h to obtain modified biochar.

[0164] The rest is consistent with Example 1.

[0165] Example 10

[0166] This embodiment provides a composite adsorption material based on modified biochar and a degradable polymer. The difference from Example 1 is:

[0167] In the preparation process of the composite adsorbent material: in step 2, a twin-screw extruder is used for melt blending at a temperature of 200°C and a speed of 200 rpm; in step 3, hot pressing is performed (pressure 11 MPa, temperature 160°C, time 12 min), and then cut into 3 mm particles;

[0168] Among them, the process of biochar modification is:

[0169] (1) The raw material (rice husk) was crushed to 200 mesh, immersed in 0.6 mol / L acetic acid solution (solid-to-liquid ratio 1:10), and stirred at 90°C for 1 h;

[0170] (2) After washing and drying, carbonization was carried out at 650°C in a nitrogen atmosphere for 0.5 h to obtain organic acid activated carbon;

[0171] (3) Fe3O4 / TiO2 was loaded on the carbon surface by a hydrothermal method with a reaction temperature of 130℃ and a reaction time of 5h to obtain modified biochar.

[0172] The rest is consistent with Example 1.

[0173] Comparative Example 1

[0174] This comparative example provides a composite adsorption material, which differs from Example 1 in that polylactic acid is not added to the formula of the composite adsorption material; the rest is consistent with Example 1.

[0175] Comparative Example 2

[0176] This comparative example provides a composite adsorption material, which differs from Example 1 in that no cross-linking agent and compatibilizer are added to the formula of the composite adsorption material; the rest is consistent with Example 1.

[0177] Comparative Example 3

[0178] This comparative example provides a composite adsorption material, which differs from Example 1 in that organic acid impregnation activation is not used during the biochar modification process; the rest is consistent with Example 1.

[0179] Comparative Example 4

[0180] This comparative example provides a composite adsorption material, which differs from Example 1 in that Fe3O4 / TiO2 is not loaded on the organic acid activated carbon during the biochar modification process; the rest is consistent with Example 1.

[0181] Comparative Example 5

[0182] This comparative example provides a composite adsorption material, which differs from Example 1 in that the biomass charcoal is not subjected to activation modification and loading modification, and pure rice husk charcoal is used. Other components and preparation methods are consistent with those of Example 1.

[0183] Comparative Example 6

[0184] This comparative example provides a composite adsorption material, which uses polyacrylamide / bentonite with a mass ratio of 1:1.

[0185] Test Case

[0186] Test samples: The composite adsorption materials prepared in Examples 1-10 and the composite adsorption materials prepared in Comparative Examples 1-6 were used as samples for testing.

[0187] Test method:

[0188] (1) Pb 2+ Adsorption. Take 100mL of a heavy metal solution of a certain concentration and place it in a 250mL conical flask, and add a certain mass of adsorption material into the flask. Place it in a constant temperature oscillator, control a certain temperature. Unless otherwise specified, the temperature is (20±1)℃, and oscillate at 140r / min for a certain time. Take a sample, filter it through a syringe filter (0.45μm), and determine the concentration of heavy metals in the filtrate. During the test, dilute hydrochloric acid and dilute NaOH solution were used to adjust the pH. Each test was repeated 3 times, and the results were averaged. Pb 2+ The concentration was analyzed by direct injection flame atomic absorption spectrometry [ASTM-D3559 (Pb)].

[0189] (2) Methyl orange adsorption rate test

[0190] Preparation: Prepare methyl orange standard solution, different adsorbents and simulated wastewater.

[0191] Adsorption experiment: Add a certain amount of simulated wastewater to a beaker and adjust the pH to the color-developing range of methyl orange. Add different adsorbents, controlling the amount and adsorption time. Place the mixture in a constant-temperature water bath for a period of time, then centrifuge. Collect the supernatant and measure the absorbance of methyl orange using a spectrophotometer.

[0192] Data processing: Calculate the concentration of methyl orange according to the standard curve, calculate the adsorption amount of the adsorbent, and analyze the adsorption effect of different adsorbents on methyl orange.

[0193] (3) Degradation rate test: The composite material was placed in a strong degradation test chamber with a temperature of 30°C and a humidity of 80% and containing biological bacteria, and the mass loss rate was recorded. The test lasted for 180 days.

[0194] (4) Vickers hardness test. A certain load is applied to the material surface, an indentation is made using a diamond pyramid indenter, and the diagonal length of the indentation is measured to calculate the hardness value. Multiple comparative tests are performed on materials of the same hardness grade.

[0195] The test results are shown in Table 1.

[0196] Table 1

[0197]

[0198]

[0199] As shown in Table 1, the composite adsorbent prepared by the present invention has a high adsorption efficiency for heavy metal ions and organic pollutants, and has a good biodegradation rate and Vickers hardness. 2+ The adsorption capacity reached 182 mg / g, the adsorption rate for methyl orange reached 98%, the degradation rate after 180 days was 70%, and the Vickers hardness reached 16.2 MPa. Data comparison shows that the material prepared by this invention has significant benefits in terms of pollutant removal rate, degradability, and strength, and is expected to be widely used in the field of environmental protection.

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite adsorption material based on modified biochar and degradable polymer, characterized in that: The invention comprises the following components: modified biochar, polylactic acid, a cross-linking agent and a compatibilizer; The biomass is sequentially subjected to organic acid activation, carbonization and magnetic composite nanoparticle loading modification treatments to obtain the modified biomass carbon.

2. The composite adsorption material based on modified biochar and degradable polymer according to claim 1, characterized in that: The organic acid includes acetic acid and / or benzenesulfonic acid; And / or, the magnetic composite nanoparticles include: one or more of Fe3O4@Au, Fe3O4@SiO2 and Fe3O4 / TiO2; And / or, the particle size of the Fe3O4 / TiO2 is 40-100 nm, the particle size of the Fe3O4@Au is 40-90 nm, and the particle size of the Fe3O4@SiO2 is 40-95 nm.

3. The composite adsorption material based on modified biochar and degradable polymer according to claim 1, characterized in that: In the modified biochar, the loading amount of the magnetic composite nanoparticles is 5 wt%-10 wt%.

4. The composite adsorption material based on modified biochar and degradable polymer according to claim 1, characterized in that: The biomass raw materials include corn stalks and / or rice husks; and / or, the biomass has a particle size of 100 to 200 mesh; and / or, the polylactic acid has an Mw of 18,000-24,000; and / or, the cross-linking agent comprises epichlorohydrin and / or methacrylic acid; And / or, the compatibilizer includes maleic anhydride grafted polylactic acid and / or ethylene glycol carbonate.

5. The composite adsorption material based on modified biochar and degradable polymer according to claim 1, characterized in that: The composite adsorption material comprises the following components in parts by mass: 40 to 60 parts of modified biochar, 30 to 40 parts of polylactic acid, 5 to 8 parts of a cross-linking agent and 5 to 10 parts of a compatibilizer.

6. The method for preparing a composite adsorption material based on modified biochar and a degradable polymer according to any one of claims 1 to 5, characterized in that: The following steps are involved: The composite adsorption material is obtained by mixing the modified biochar, polylactic acid, a cross-linking agent and a compatibilizer in a prescribed amount.

7. The preparation method according to claim 6, characterized in that The preparation process of the modified biochar includes: (a) mixing biomass with an organic acid and carbonizing the mixture to obtain organic acid activated carbon; (b) loading the magnetic composite nanoparticles on the organic acid activated carbon; and / or, the concentration of the organic acid is 0.4-0.6 mol / L; And / or, in step (a), the temperature of the mixing process is 70-90° C. and the stirring time is 1-3 h; And / or, in step (a), the carbonization temperature is 550-650° C.; the carbonization time is 0.5-1.5 h; And / or, in step (b), the magnetic composite nanoparticles are loaded on the organic acid activated carbon by a hydrothermal method, the reaction temperature is 110-130° C., and the reaction time is 5-7 hours.

8. The preparation method according to claim 7, characterized in that Fe3O4 nanoparticles are used as the core material, and the outside of the Fe3O4 nanoparticles is wrapped with a coating layer; And / or, the coating layer includes one or more of Au, SiO2 and TiO2.

9. The preparation method according to claim 6, characterized in that The mixing process of the modified biochar, polylactic acid, cross-linking agent and compatibilizer includes: melt blending at 180-200° C.; and / or, melt blending followed by hot pressing and cutting; And / or, the hot pressing molding is performed at a pressure of 9-11 MPa, a temperature of 160-180° C., and a time of 8-12 min.

10. Use of the composite adsorption material based on modified biochar and a degradable polymer according to any one of claims 1 to 5, or the composite adsorption material based on modified biochar and a degradable polymer prepared by the preparation method according to any one of claims 6 to 9 in industrial pollution control.

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