Biomass-based polydopamine / nano oxide water body heavy metal adsorption material as well as preparation method and application thereof

Abstract

The invention discloses a biomass-based polydopamine / nano oxide water body heavy metal adsorption material and a preparation method and application thereof, and belongs to the technical field of environmental functional materials, the preparation method comprises the following steps: adding a crushed biomass raw material into an acetone-water solution, stirring, and filtering for later use; preparing a periodate solution, adding a Tris solution and soluble dopamine hydrochloride to enable the concentration of dopamine to be 10-200mM, then adding the biomass raw material subjected to acetone-water treatment, stirring and reacting at room temperature, washing and drying to obtain a solid; and finally, adding zirconium oxychloride octahydrate into water, then adding the dried solid, carrying out oscillation reaction at room temperature, filtering, drying, further treating with a mixed solution of sodium hydroxide and sodium chloride, washing, and drying to obtain the biomass-based polydopamine / nano oxide water body heavy metal adsorption material. According to the invention, the problems of small particle size, easy agglomeration, difficult separation, difficult regeneration and the like of the nano adsorbent are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental functional materials, and in particular relates to a biomass-based polydopamine / nano-oxide water body heavy metal adsorption material and a preparation method and application thereof. Background Art

[0002] Heavy metal pollution in water bodies has become a pressing environmental issue. Highly toxic, non-degradable, and bioaccumulative, heavy metals can accumulate through the food chain, ultimately harming human health and causing various illnesses and even death. Industrial wastewater discharge, mining, agricultural non-point source pollution, and urban runoff are the primary sources. The long-term retention of heavy metal pollutants such as cadmium, lead, mercury, and arsenic in aquatic environments not only leads to the degradation of aquatic ecosystems but can also cause Minamata disease and Itai-itai disease, leading to hereditary genetic defects. Deep purification of heavy metal-contaminated water bodies has become a top priority in the environmental protection field.

[0003] Currently, methods for removing heavy metals from water primarily include chemical precipitation, redox, electrochemical, membrane separation, and ion exchange. However, most of these methods lack deep treatment capabilities, suffer from poor selectivity, or have high operating costs. Adsorption, due to its advantages such as simplicity, economic feasibility, high selectivity, stable deep treatment performance, and the potential for waste resource utilization, has become a research hotspot in the field of deep heavy metal treatment.

[0004] Nanomaterials are favored by researchers due to their large adsorption capacity and high adsorption selectivity. However, most nanomaterials are in powder form and easily agglomerate in water, preventing them from performing well. Chinese patent publication CN103301819A discloses a method for preparing a nano-adsorbent for removing heavy metals from wastewater. The invention first pre-treats a macroporous cation exchange resin, soaking the pre-treated resin in solutions of manganese (II) salt, cerium (III) salt, and titanium (III) salt, followed by soaking and oxidation with a mixed solution of sodium persulfate and NaOH. A chemical reaction occurs within the macroporous resin to produce well-dispersed nano-hydrated manganese oxide and hydrated titanium oxide precipitates. The mixture is then dried and dehydrated at 50°C for 3 hours to produce an adsorbent loaded with nano-hydrated manganese oxide and hydrated titanium oxide. Chinese patent publication CN114225897A discloses a modified attapulgite-loaded nano-zero-valent iron composite material, its preparation method, and application. The invention involves calcining attapulgite, dispersing the calcined attapulgite and a surfactant in deionized water, and then sonicating and stirring to obtain a mixed solution. Iron salt and ethanol are added to the mixed solution, followed by continued sonication and stirring. Under an inert gas atmosphere, a borohydride salt solution is added dropwise to the resulting mixed solution. The solution is then rinsed, centrifuged, and vacuum-dried to obtain the modified attapulgite-loaded nano-zero-valent iron composite material. While these inventions enhance the dispersibility of nanomaterials through the use of carriers, they may pose a risk of nanomaterial shedding or dissolution.

[0005] Therefore, there is an urgent need to develop an environmental functional material with good stability, low risk of nanomaterial shedding and dissolution, and strong adsorption affinity for heavy metals. Summary of the Invention

[0006] In order to address the problems of small particle size of nano-adsorbents, easy agglomeration in practical applications resulting in loss of adsorption sites, difficulty in separation, and difficulty in regeneration, the present invention provides a biomass-based polydopamine / nano-oxide water body heavy metal adsorption material, which has a simple preparation method, can be repeatedly regenerated, has strong heavy metal adsorption capacity, and has significant specific adsorption of heavy metals in contaminated water bodies containing strong competing ions.

[0007] The specific technical solutions adopted are as follows:

[0008] A method for preparing a biomass-based polydopamine / nano-oxide water body heavy metal adsorption material comprises the following steps:

[0009] (1) adding the crushed biomass raw material into an acetone-water solution, stirring, filtering and setting aside;

[0010] (2) preparing a periodate solution, adding a Tris solution and adjusting the pH to 8-10, then adding soluble dopamine hydrochloride to adjust the dopamine concentration to 10-200 mM, adding the biomass raw material treated in step (1) to the above solution, stirring at room temperature for 8-15 hours, washing, and drying;

[0011] (3) adding zirconium oxychloride octahydrate to water, and then adding the material obtained in step (2), shaking the reaction at room temperature for 2 to 12 hours, filtering, and adding the solid obtained after natural drying to a mixed solution of sodium hydroxide and sodium chloride, shaking the reaction at room temperature for 2 to 12 hours, washing, and drying to obtain the biomass-based polydopamine / nanooxide water-based heavy metal adsorption material.

[0012] The present invention uses biomass raw materials, represented by agricultural waste, as a starting point. By coating the surface of the pretreated biomass raw materials with a dopamine polymer and then grafting nano-zirconia, an environmentally friendly, uniformly sized, excellent adsorption performance, and easily separable and regenerated biomass-based polydopamine / nano-oxide water-based heavy metal adsorption material is produced. The biomass raw materials are environmentally friendly and low-cost. The active groups on the surface of the acetone-water-treated biomass raw materials can bind to functional groups such as o-quinone, amino, imine, and phenolic hydroxyl groups contained in the polydopamine structure through hydrogen bonding or covalent bonding. The highly negatively charged surface of the polydopamine greatly promotes the uniform dispersion of nanoparticles on the carrier surface, significantly improving the utilization rate of the active sites of the nano-zirconia, effectively unleashing the adsorption potential of nano-zirconia for heavy metals, and resolving the technical bottleneck of its easy aggregation and difficulty in separation.

[0013] Optionally, the biomass raw materials include but are not limited to bayberry kernels, walnut shells, coconut shells, peanut shells or wheat straw, and the particle size after crushing is 0.5 to 2 mm.

[0014] Preferably, in step (1), the volume ratio of the crushed biomass raw material to the acetone-water solution is 1 g: 20-100 mL, and the volume fraction of acetone in the acetone-water solution is 10-50%. The acetone-water solution treatment has a modification effect, improving the binding ability of the biomass raw material with dopamine and affecting its microstructure.

[0015] Furthermore, the periodate is NaIO4, the concentration of the periodate solution is 20-500 mM, and the volume ratio of the biomass raw material added after the treatment in step (1) to the solution is 1 g:40-200 mL.

[0016] Furthermore, the ratio of zirconium oxychloride octahydrate, water and the material obtained in step (2) is 0.05-0.2 mol:100 mL:0.5-2.5 g.

[0017] Furthermore, in the mixed solution of sodium hydroxide and sodium chloride, the mass fraction of sodium hydroxide is 8-12 wt %, and the mass fraction of sodium chloride is 3-7 wt %.

[0018] The present invention also provides a biomass-based polydopamine / nano-oxide water body heavy metal adsorption material prepared by the preparation method of the biomass-based polydopamine / nano-oxide water body heavy metal adsorption material.

[0019] The biomass-based polydopamine / nano oxide water heavy metal adsorption material contains nano zirconium oxide with a specific surface area of 80 to 200 m 2 / g, a zero charge point of 3 to 4, wherein the size of the nano-zirconia is between 20 and 200 nm, and the solid loading is 15 to 35 wt%.

[0020] The biomass-based polydopamine / nano-oxide water heavy metal adsorption material can be desorbed and regenerated through a salt-alcohol three-system mixed solution, wherein the alcohol in the salt-alcohol three-system mixed solution is ethanol, the acid is HCl or HNO3, and the salt is NaCl, and the mass concentrations of the acid and the salt are both 1-5wt%, and the volume fraction of ethanol is 5-15%.

[0021] Experimental verification shows that when the biomass-based polydopamine / nano-oxide water body heavy metal adsorption material is used to treat heavy metal-contaminated water, the adsorption capacity for lead, copper, and cadmium can reach 80-150 mg / g, 20-50 mg / g, and 30-60 mg / g, respectively, with good adsorption effect.

[0022] The present invention also provides a method for treating heavy metal-contaminated water bodies, which utilizes the biomass-based polydopamine / nano-oxide water body heavy metal adsorption material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention has developed a biomass-based polydopamine / nano-oxide water body heavy metal adsorption material with good stability. The preparation process is simple and fast, the conditions are mild, it is environmentally friendly, there is no secondary pollution, and the cost is low. It can be mass-produced. The biomass-based polydopamine / nano-oxide water body heavy metal adsorption material has a strong adsorption capacity for heavy metals. The adsorption capacity for lead, copper, and cadmium can reach 80-150 mg / g, 20-50 mg / g, and 30-60 mg / g, respectively. After being reused 4 times, the adsorption capacity can still be guaranteed to be above 80% of the initial adsorption amount.

[0025] (2) The present invention solves the problem that the active substances of the existing composite materials are easy to fall off and unstable by coating the surface of the pretreated biomass raw materials with dopamine polymer and then grafting nano-zirconia. The binding force between the biomass raw materials after acetone-water treatment and polydopamine is strong. The high negative charge property of the polydopamine surface can greatly promote the uniform dispersion of nanoparticles on the carrier surface, significantly improve the utilization rate of the active sites of nano-zirconia, and can effectively exert the adsorption potential of nano-zirconia for heavy metals, solving the technical bottleneck of its easy agglomeration and difficult separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope image of the biomass-based polydopamine / nano-oxide water heavy metal adsorption material in Example 5.

[0027] Figure 2 This is the Zeta potential analysis diagram of the biomass-based polydopamine / nanooxide water heavy metal adsorption material in Example 5.

[0028] Figure 3 This is the Pb(II) adsorption isotherm of the biomass-based polydopamine / nano-oxide water heavy metal adsorption material in Example 5. DETAILED DESCRIPTION

[0029] In order to make the objects, features and advantages of the present invention more clearly understood, a detailed description is given below using specific embodiments. In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in the various embodiments of the present invention can be combined accordingly without conflicting with each other.

[0030] The procedures for the following examples, in which specific conditions are not specified, generally follow conventional conditions or those recommended by the manufacturer. Any material not described in detail in this specification belongs to the prior art known to those skilled in the art. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0031] Example 1

[0032] (1) Add 0.5 g of crushed bayberry seeds (particle size of about 1 mm) into 50 mL of acetone-water solution (acetone volume fraction of 10%), stir at room temperature for 30 min, and filter for later use.

[0033] (2) Prepare 100 mL of 30 mM periodate (NaIO4), add 50 mM tris (hydroxymethylaminomethane) (Tris) solution and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to a dopamine concentration of 15 mM. Slowly add 0.5 g of the material obtained in step (1) to the above solution (about 40 mL), and stir at 150 rpm at room temperature for 12 h. Filter and wash with water until neutral, and dry in a vacuum at 30°C for 24 h.

[0034] (3) 0.05 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 0.5 g of the material obtained in step (2) was added. The mixture was placed in a shaker for 3 h at room temperature and then filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 8 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 3 h, washed with water until neutral, and vacuum dried at 30 ° C for 24 h to prepare the bayberry core-based polydopamine / nanooxide aqueous heavy metal adsorption material.

[0035] The size of the nano zirconium oxide in the prepared bayberry core-based polydopamine / nano oxide water heavy metal adsorption material is between 160 and 180 nm, the solid loading is 15%, and the specific surface area is 80 m 2 / g, with a zero charge point of 3.8. It was applied to the treatment of lead pollution in water. The initial concentration of Pb(II) in the water was 30mg / L, the adsorbent dosage was 0.5g / L, and the adsorption capacity of Pb(II) was 60mg / g at room temperature and a solution pH of 5.

[0036] Example 2

[0037] (1) Add 1 g of crushed walnut shells (particle size of about 1.2 mm) to 50 mL of acetone-water solution (acetone volume fraction of 20%), stir at room temperature for 30 min, and filter for later use.

[0038] (2) Prepare 100 mM periodate (NaIO4) solution, add 50 mM tris (hydroxymethylaminomethane) (Tris) solution and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 50 mM. Slowly add 1 g of the material obtained in step (1) to the above solution (about 80 mL) and stir at 150 rpm at room temperature for 12 h. Filter and wash with water until neutral, and dry in a vacuum at 40°C for 24 h.

[0039] (3) 0.08 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 1 g of the material obtained in step (2) was added. The mixture was placed in a shaker at room temperature for 5 h and then filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 10 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 5 h, washed with water until neutral, and vacuum dried at 40 ° C for 24 h to prepare a walnut shell-based polydopamine / nano oxide aqueous heavy metal adsorption material.

[0040] The size of the nano-zirconia in the walnut shell-based polydopamine / nano-oxide water heavy metal adsorption material prepared above is between 140 and 165 nm, the solid loading is 19.2%, and the specific surface area is 96.5 m 2 / g, and its zero charge point is 3.6. It was applied to the treatment of copper pollution in water. The initial concentration of Cu(II) in the water was 30mg / L, and the adsorbent dosage was 1g / L. At room temperature and a solution pH of 5, the material adsorbed 42mg / g of Cu(II).

[0041] Example 3

[0042] (1) Add 1.5 g of crushed coconut shell (particle size is about 1 mm) into 50 mL of acetone-water solution (acetone volume fraction is 30%), stir at room temperature for 30 min, and filter for later use.

[0043] (2) Prepare 100 mL of 200 mM periodate (NaIO4), add 100 mM tris (hydroxymethylaminomethane) (Tris) solution and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 100 mM. Slowly add 1 g of the material obtained in step (1) to the above solution (about 80 mL) and stir at 150 rpm at room temperature for 12 hours. Filter and wash with water until neutral, and vacuum dry at 50°C for 24 hours.

[0044] (3) 0.13 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 1 g of the material obtained in step (2) was added. The mixture was placed in a shaker for 6 h at room temperature and filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 12 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 6 h, washed with water until neutral, and vacuum dried at 50 ° C for 24 h to prepare the coconut shell-based polydopamine / nano oxide aqueous heavy metal adsorption material.

[0045] The size of the nano-zirconia in the coconut shell-based polydopamine / nano-oxide water heavy metal adsorption material prepared above is between 120 and 140 nm, the solid loading is 22.7%, and the specific surface area is 109.5 m 2 / g, and its zero charge point is 3.3. It was applied to the treatment of chromium pollution in water. The initial concentration of Cd(II) in the water was 60mg / L, and the adsorbent dosage was 0.5g / L. At room temperature and a solution pH of 5.8, the material adsorbed 51mg / g of Cd(II).

[0046] Example 4

[0047] (1) Add 2 g of crushed peanut shells (particle size of about 1 mm) to 50 mL of acetone-water solution (acetone volume fraction of 40%), stir at room temperature for 30 min, and filter for later use.

[0048] (2) Prepare 100 mL of 300 mM periodate (NaIO4), add 50 mM tris (hydroxymethylaminomethane) (Tris) solution and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 200 mM. Slowly add 1 g of the material obtained in step (1) to the above solution (about 80 mL) and stir at 150 rpm at room temperature for 12 h. Filter and wash with water until neutral, and vacuum dry at 50°C for 24 h.

[0049] (3) 0.15 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 0.5 g of the material obtained in step (2) was added. The mixture was placed in a shaker at room temperature for 8 h and then filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 10 wt% (NaOH) + 6 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 8 h, washed with water until neutral, and vacuum dried at 50 ° C for 24 h to prepare a peanut shell-based polydopamine / nano oxide aqueous heavy metal adsorption material.

[0050] The size of the nano-zirconia in the peanut shell-based polydopamine / nano-oxide water heavy metal adsorption material prepared above is between 100 and 130 nm, the solid loading is 25%, and the specific surface area is 112 m 2 / g, and its zero charge point is 3.4. It was applied to the treatment of lead pollution in water. The initial concentration of Pb(II) in the water was 100mg / L, the adsorbent dosage was 0.5g / L, and at room temperature and a solution pH of 5.5, the material adsorbed 78mg / g of Pb(II).

[0051] Example 5

[0052] (1) Add 2.5 g of crushed wheat straw (particle size of about 2 mm) into 50 mL of acetone-water solution (acetone volume fraction of 50%), stir at room temperature for 30 min, and filter for later use.

[0053] (2) Prepare 100 mL of 500 mM periodate (NaIO4), add 100 mM tris (hydroxymethylaminomethane) (Tris) solution and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 200 mM. Slowly add 1 g of the material obtained in step (1) to the above solution (about 80 mL) and stir at 150 rpm at room temperature for 12 hours. Filter and wash with water until neutral, then dry in a vacuum at 60°C for 24 hours.

[0054] (3) 0.1 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 0.5 g of the material obtained in step (2) was added. The mixture was placed in a shaker for 12 h at room temperature and filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 10 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 12 h, washed with water until neutral, and vacuum dried at 60 ° C for 24 h to prepare the straw-based polydopamine / nanooxide aqueous heavy metal adsorption material.

[0055] The size of the nano-zirconia in the straw-based polydopamine / nano-oxide water heavy metal adsorption material prepared above is between 20 and 50 nm (SEM image as shown in FIG Figure 1 The solid loading is 30.2%, and its specific surface area is 117.4m 2 / g, the zero charge point is 3.1 (such as Figure 2 It was applied to the treatment of lead, copper and chromium pollution in water. The initial concentrations of Pb(II), Cu(II) and Cd(II) in water were all 100 mg / L, and the adsorbent dosage was 0.5 g / L. At room temperature and a solution pH of 5.5, the adsorption capacities of the material for Pb(II), Cu(II) and Cd(II) were 100 mg / g, 45 mg / g and 56 mg / g, respectively. The representative Pb(II) adsorption isotherms are shown in Figure 2. Figure 3 shown.

[0056] After the above material is saturated with adsorption, it is placed in a mixed solution of 5wt% HCl+5wt% NaCl+5% (V / V) ethanol for elution, and the desorption effect can reach more than 80%. The desorbed straw-based polydopamine / nano-oxide water heavy metal adsorption material can continue to be used for the next cyclic adsorption, and the next adsorption can still maintain more than 80% of the initial adsorption amount.

[0057] Example 6

[0058] (1) Add 2 g of crushed wheat straw (particle size of about 2 mm) to 50 mL of acetone-water solution (acetone volume fraction of 20%), stir at room temperature for 30 min, and filter for later use.

[0059] (2) Prepare 100 mL of 100 mM periodate (NaIO4), add 50 mM tris (hydroxymethylaminomethane) (Tris) solution, and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 100 mM. Slowly add 1.2 g of the material obtained in step (1) to the above solution (about 100 mL) and stir at 150 rpm at room temperature for 12 hours. Filter and wash with water until neutral, and vacuum dry at 40°C for 24 hours.

[0060] (3) 0.15 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 2 g of the material obtained in step (2) was added. The mixture was placed in a shaker for 10 h at room temperature and filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 10 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 10 h, washed with water until neutral, and vacuum dried at 40 ° C for 24 h to prepare the straw-based polydopamine / nano oxide aqueous heavy metal adsorption material.

[0061] The size of the nano-zirconia in the straw-based polydopamine / nano-oxide water heavy metal adsorption material prepared above is between 60 and 80 nm, the solid loading is 27.6%, and the specific surface area is 113.8 m 2 / g, and its zero charge point is 3.2. It was applied to the treatment of lead pollution in water. The initial concentration of Pb(II) in the water was 90mg / L, and the adsorbent dosage was 0.5g / L. At room temperature and a solution pH of 5.5, the material adsorbed 82mg / g of Pb(II).

[0062] Comparative Example 1

[0063] (1) Add 2 g of crushed wheat straw (particle size is about 1 mm) into 50 mL of aqueous solution, stir at room temperature for 30 min, and filter for later use.

[0064] (2) Prepare 100 mL of 100 mM periodate (NaIO4), add 50 mM tris (hydroxymethylaminomethane) (Tris) solution, and adjust the pH of the solution to 8-10. Add soluble dopamine hydrochloride (DA-HCl) to the solution to maintain the dopamine concentration at 100 mM. Slowly add 1.2 g of the material obtained in step (1) to the above solution (about 100 mL) and stir at 150 rpm at room temperature for 12 hours. Filter and wash with water until neutral, and vacuum dry at 40°C for 24 hours.

[0065] (3) 0.15 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added to 100 mL of water, and then 2 g of the material obtained in step (2) was added. The mixture was placed in a shaker for 10 h at room temperature and filtered. The dry solid obtained after natural sun drying / air drying was added to 100 mL of 10 wt% (NaOH) + 5 wt% (NaCl) NaOH + NaCl solution, shaken at room temperature for 10 h, washed with water until neutral, and vacuum dried at 40 ° C for 24 h to prepare a water-based heavy metal adsorption material.

[0066] The size of the nano zirconium oxide in the heavy metal adsorption material prepared above is between 300 and 500 nm, the solid loading is 10%, and the specific surface area is 30 m 2 / g, and the material's zero charge point is 5. It was applied to the treatment of lead pollution in water. The initial concentration of Pb(II) in the water was 90mg / L, the adsorbent dosage was 0.5g / L, and the material adsorbed 12mg / g of Pb(II) at room temperature and a solution pH of 5.5.

[0067] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a biomass-based polydopamine / nano-oxide water-based heavy metal adsorption material, characterized in that: The following steps are involved: (1) adding the crushed biomass raw material into an acetone-water solution, stirring, filtering and setting aside; (2) preparing a periodate solution, adding a Tris solution and adjusting the pH to 8-10, then adding soluble dopamine hydrochloride to adjust the dopamine concentration to 10-200 mM, adding the biomass raw material treated in step (1) to the above solution, stirring at room temperature for 8-15 hours, washing, and drying; (3) adding zirconium oxychloride octahydrate to water, and then adding the material obtained in step (2), shaking the reaction at room temperature for 2 to 12 hours, filtering, and adding the solid obtained after natural drying to a mixed solution of sodium hydroxide and sodium chloride, shaking the reaction at room temperature for 2 to 12 hours, washing, and drying to obtain the biomass-based polydopamine / nanooxide water-based heavy metal adsorption material.

2. The method for preparing the biomass-based polydopamine / nano-oxide water heavy metal adsorption material according to claim 1, characterized in that: The biomass raw materials include bayberry kernels, walnut shells, coconut shells, peanut shells or wheat straws, and the particle size after crushing is 0.5-2 mm.

3. The method for preparing the biomass-based polydopamine / nano-oxide water heavy metal adsorption material according to claim 1, characterized in that: In step (1), the volume ratio of the added amount of the crushed biomass raw material to the acetone-water solution is 1 g: 20-100 mL, and the volume fraction of acetone in the acetone-water solution is 10-50%.

4. The method for preparing the biomass-based polydopamine / nano-oxide water-based heavy metal adsorption material according to claim 1, characterized in that: The periodate is NaIO4, and the volume ratio of the biomass raw material added after the treatment in step (1) to the solution is 1g:40-200mL.

5. The method for preparing the biomass-based polydopamine / nano-oxide water-based heavy metal adsorption material according to claim 1, characterized in that: The ratio of zirconium oxychloride octahydrate, water and the material obtained in step (2) is 0.05-0.2 mol:100 mL:0.5-2.5 g.

6. The method for preparing the biomass-based polydopamine / nano-oxide water-based heavy metal adsorption material according to claim 1, characterized in that: In the mixed solution of sodium hydroxide and sodium chloride, the mass fraction of sodium hydroxide is 8-12wt%, and the mass fraction of sodium chloride is 3-7wt%.

7. The biomass-based polydopamine / nano-oxide water body heavy metal adsorption material prepared by the preparation method of the biomass-based polydopamine / nano-oxide water body heavy metal adsorption material according to any one of claims 1 to 6.

8. The biomass-based polydopamine / nano-oxide water heavy metal adsorption material according to claim 7, characterized in that: The biomass-based polydopamine / nano oxide water heavy metal adsorption material contains nano zirconium oxide with a specific surface area of 80 to 200 m 2 / g, a zero charge point of 3 to 4, wherein the size of the nano-zirconia is between 20 and 200 nm, and the solid loading is 15 to 35 wt%.

9. The biomass-based polydopamine / nano-oxide water heavy metal adsorption material according to claim 7, characterized in that: The biomass-based polydopamine / nano-oxide water heavy metal adsorption material is desorbed and regenerated through a salt-alcohol three-system mixed solution, wherein the alcohol in the salt-alcohol three-system mixed solution is ethanol, the acid is HCl or HNO3, and the salt is NaCl, and the mass concentrations of the acid and the salt are both 1-5wt%, and the volume fraction of ethanol is 5-15%.

10. A method for treating heavy metal contaminated water, characterized in that: Utilize the biomass-based polydopamine / nano-oxide water heavy metal adsorption material described in any one of claims 7 to 9.

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