Aluminosilicate solid waste heavy metal adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of preparation of metal adsorbents by utilizing solid wastes, in particular to an aluminosilicate solid waste heavy metal adsorbent as well as a preparation method and application thereof. The aluminosilicate solid waste heavy metal adsorbent is prepared from the following components in parts by mass: 30 to 50 parts of modified aluminosilicate solid waste, 20 to 40 parts of modified sawdust biochar and 1.2 to 1.6 parts of sodium alginate, the preparation method of the modified sawdust biochar comprises the following steps: S1, preparing a modified solution: dissolving catechol in an aqueous solution of 25% ethanol, and adding a composite solvent to obtain the modified solution; and S2, mixing the sawdust biochar with the modified solution according to a mass ratio of 1: 15, magnetically stirring at room temperature for 1 hour, filtering and drying to obtain the modified sawdust biochar.

Description

Technical Field

[0001] This application relates to the technical field of solid waste utilization for preparing metal adsorbents, and particularly relates to an aluminosilicate solid waste heavy metal adsorbent, its preparation method and application. Background Art

[0002] With the development of industrial production and mining, water pollution is relatively obvious. Among them, the pollution problems of oxygen-containing anions of lead (such as PbO 3 - , Pb(OH) 3- ) and oxygen-containing anions of arsenic (AsO 3 3- , AsO 4 3- ) are becoming increasingly prominent; these pollutants mainly come from non-ferrous metal smelting, electroplating, chemical industry, pesticide production and mine wastewater. Oxygen-containing anions of lead and oxygen-containing anions of arsenic are easily combined with particulate matter and colloids in water, migrate with the water flow or deposit in the sediment, forming long-term pollution sources, which are characterized by strong toxicity, easy migration and difficult natural degradation.

[0003] In the prior art, common treatment methods include ion exchange method, chemical precipitation and adsorption method. However, the chemical precipitation method usually adjusts the pH by adding a large amount of alkali to form Pb(OH) 2 precipitate and Ca 3 (AsO 4 ) 2 and other insoluble salts, but this is likely to produce a large amount of heavy metal sludge and has a low removal efficiency for low-concentration pollutants; the ion exchange method relies on resin materials, with high costs and poor adaptability to complex water quality; traditional adsorbent materials such as activated carbon and zeolite have problems of low adsorption capacity and insufficient selectivity, and it is particularly difficult to efficiently remove lead and arsenic in anionic form.

[0004] Therefore, developing an environmentally friendly and efficient adsorbent material has important environmental and social benefits. Summary of the Invention

[0005] This application provides an aluminosilicate solid waste heavy metal adsorbent, its preparation method and application to solve the problems mentioned in the background art.

[0006] In the first aspect, an aluminosilicate solid waste heavy metal adsorbent is provided, which includes: 30 - 50 parts of modified aluminosilicate solid waste, 20 - 40 parts of modified sawdust biochar and 1.2 - 1.6 parts of sodium alginate; The preparation method of the modified sawdust biochar includes: S1. Preparation of modified solution: Dissolve catechol in an aqueous solution of 25% ethanol, and then add a composite solvent to obtain a modified solution, where the mass-volume ratio of catechol to the aqueous solution of 25% ethanol is 1 g:(15 - 20) mL; S2. Mix the sawdust biochar with the modified solution at a mass ratio of 1:15, stir magnetically at room temperature for 1 h, filter and dry to obtain modified sawdust biochar.

[0007] Preferably, the composite solvent includes sorbic acid, potassium sorbate and tannic acid with a mass ratio of 1:0.2:(0 - 5), and the preparation method of the composite solvent includes: Dissolve sorbic acid in absolute ethanol, add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water and then add it to the mixed solution to obtain a composite solvent, where the mass-volume ratio of sorbic acid to absolute ethanol is 1 g:20 mL, and the mass-volume ratio of tannic acid to deionized water is 1 g:40 mL.

[0008] Preferably, the preparation method of the sawdust biochar includes: Dry the sawdust, pyrolyze the sawdust at 400 - 600 °C under a nitrogen atmosphere for 2 h, and cool to room temperature to obtain sawdust biochar.

[0009] Preferably, the preparation method of the modified aluminosilicate solid waste includes: Mix sodium silicate, calcium hydroxide and aluminosilicate solid waste in a mass ratio of (0.2 - 0.4):(0.2 - 0.4):1, stir, then add cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain modified aluminosilicate solid waste, where the mass of cetyltrimethylammonium bromide is 3 - 8% of the mass of aluminosilicate solid waste.

[0010] Preferably, the aluminosilicate solid waste includes at least one of fly ash, water quenching slag and blast furnace slag.

[0011] In the second aspect, a preparation method of the above aluminosilicate solid waste heavy metal adsorbent is provided, which includes the following steps: Mix the modified aluminosilicate solid waste with the modified sawdust biochar, grind it into 0.5 mm powder, mix the powder with a 2 wt% sodium alginate solution, stir for 20 min, stand at room temperature for 1 - 2 h, and dry to obtain the aluminosilicate solid waste heavy metal adsorbent.

[0012] Preferably, the drying conditions are vacuum drying at 60 - 80 °C for 6 - 12 h.

[0013] In the third aspect, an application of the above aluminosilicate solid waste heavy metal adsorbent in the adsorption of oxygen-containing anions of lead and oxygen-containing anions of arsenic is provided.

[0014] The beneficial effects brought by the technical solution provided in this application include: This application provides an aluminosilicate solid waste heavy metal adsorbent, its preparation method and application. Its main raw materials include aluminosilicate solid waste and sawdust biochar. As an industrial by-product, aluminosilicate solid waste contains abundant silicon-aluminum active sites. Through modification, its porous structure and ion exchange characteristics effectively improve the adsorption capacity of the prepared adsorbent for oxygen-containing anions of lead and arsenic. As a biomass waste, sawdust biochar obtains charge properties and coordination ability after surface modification, and realizes the directional capture of target pollutants (oxygen-containing anions of lead and arsenic) through chemical coordination and electrostatic adsorption, without introducing additional pollutants. While effectively removing oxygen-containing anions of lead and arsenic in water, it meets the environmental protection benefits and economic value of "treating waste with waste". Brief Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is the preparation flow chart of the modified sawdust biochar provided in this application; Figure 2 It is the SEM photograph of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided in this application; Figure 3 It is the Zeta potential diagram of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided in this application; Figure 4 It is for the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided in this application for PbO 3 - Adsorption efficiency schematic diagram; Figure 5 It is for the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided in this application for AsO 3 3- Adsorption efficiency schematic diagram. Detailed Description of the Embodiments

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0018] See Figures 1 to 5 As shown, this application provides an aluminosilicate solid waste heavy metal adsorbent (hereinafter referred to as the adsorbent), which includes: 30 - 50 parts of modified aluminosilicate solid waste, 20 - 40 parts of modified sawdust biochar, and 1.2 - 1.6 parts of sodium alginate.

[0019] Among them, the preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve catechol in an aqueous solution of 25% ethanol, and then add a composite solvent to obtain the modified solution, where the mass - to - volume ratio of catechol to the aqueous solution of 25% ethanol is 1 g:(15 - 20) mL; S2. Mix the sawdust biochar with the modified solution in a mass ratio of 1:15, stir magnetically at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0020] Among them, the aqueous solution of 25% ethanol means that the volume ratio of ethanol to water is 1:4.

[0021] Further, the above - mentioned composite solvent includes sorbic acid, potassium sorbate, and tannic acid in a mass ratio of 1:0.2:(0 - 5), and the preparation method of the composite solvent includes: Dissolve sorbic acid in absolute ethanol in a mass - to - volume ratio of 1:20, add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water in a mass - to - volume ratio of 1:40 and then add it to the mixed solution to obtain the composite solvent.

[0022] Specifically, dissolve sorbic acid in absolute ethanol, add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water and then add it to the mixed solution to obtain the composite solvent, where the mass - to - volume ratio of sorbic acid to absolute ethanol is 1 g:20 mL, and the mass - to - volume ratio of tannic acid to deionized water is 1 g:40 mL.

[0023] Among them, the preparation method of the sawdust biochar includes: Dry the sawdust, pyrolyze the sawdust at 400 - 600 °C under a nitrogen atmosphere for 2 h, and cool to room temperature to obtain the sawdust biochar.

[0024] In some embodiments, the preparation method of the modified aluminosilicate solid waste includes: Mix sodium silicate, calcium hydroxide and aluminosilicate solid waste in a mass ratio of (0.2~0.4):(0.2~0.4):1, stir, then add cetyltrimethylammonium bromide, and continue to stir at 60°C for 30 min to obtain the modified aluminosilicate solid waste. The mass of the cetyltrimethylammonium bromide is 3~8% of the mass of the aluminosilicate solid waste.

[0025] In some embodiments, the aluminosilicate solid waste includes at least one of fly ash, water quenching slag, and blast furnace slag.

[0026] The preparation method of the heavy metal adsorbent for aluminosilicate solid waste provided by this application includes the following steps: Mix the modified aluminosilicate solid waste with the modified sawdust biochar and grind it into 0.5 mm powder. Mix the powder with a 2 wt% sodium alginate solution in a mass ratio of 1:(0.8~2), stir for 20 min, let it stand at room temperature for 1~2 h, and dry to obtain the heavy metal adsorbent for aluminosilicate solid waste.

[0027] Furthermore, the drying conditions are vacuum drying at 60~80°C for 6~12 h, reducing the contact between the modified part of the adsorbent and air to ensure activity, and low-temperature drying helps to retain the pore structure of the adsorbent.

[0028] Example 1 The heavy metal adsorbent for aluminosilicate solid waste provided in this example includes 400 g of modified aluminosilicate solid waste, 300 g of modified sawdust biochar, and 12 g of sodium alginate.

[0029] The preparation method of the heavy metal adsorbent for aluminosilicate solid waste is: Mix 400 g of modified aluminosilicate solid waste with 300 g of modified sawdust biochar, grind it into 0.5 mm powder, mix the powder with 600 g of a 2 wt% sodium alginate solution, stir for 20 min, let it stand at room temperature for 1 h, and vacuum dry at 60°C for 8 h to obtain the heavy metal adsorbent for aluminosilicate solid waste.

[0030] Among them, the preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve 25 g of catechol in 500 mL of an aqueous solution of 25% ethanol, and then add 6 L of the composite solvent to obtain the modified solution; The preparation method of the composite solvent is: Dissolve 100 g of sorbic acid in 2 L of absolute ethanol, add 20 g of potassium sorbate and stir evenly to obtain a mixed solution. Dissolve 100 g of tannic acid in 4 L of deionized water and add it to the mixed solution to obtain the composite solvent.

[0031] S2. Mix 400 g of sawdust biochar with 6 kg of the modified solution, stir magnetically at room temperature for 1 h, filter and dry to obtain modified sawdust biochar.

[0032] The preparation method of the sawdust biochar is as follows: After drying the sawdust, pyrolyze the sawdust in a nitrogen atmosphere at 500 °C for 2 h, and cool to room temperature to obtain sawdust biochar.

[0033] Among them, the preparation method of the modified aluminosilicate solid waste includes: Mix 90 g of sodium silicate, 90 g of calcium hydroxide, 180 g of fly ash, and 120 g of water quenched slag, stir, and then add 15 g of cetyltrimethylammonium bromide. Continue to stir at 60 °C for 30 min to obtain modified aluminosilicate solid waste.

[0034] Example 2 The difference from Example 1 is that in step S1, the preparation method of the composite solvent is as follows: Dissolve 100 g of sorbic acid in 2 L of absolute ethanol, add 20 g of potassium sorbate and stir evenly to obtain a mixed solution. Then continue to add 4 L of deionized water to the mixed solution to obtain the composite solvent.

[0035] Example 3 The aluminosilicate solid waste heavy metal adsorbent provided in this example includes 300 g of modified aluminosilicate solid waste, 400 g of modified sawdust biochar, and 14 g of sodium alginate.

[0036] The preparation method of the aluminosilicate solid waste heavy metal adsorbent is as follows: Mix 300 g of modified aluminosilicate solid waste with 400 g of modified sawdust biochar, grind them into 0.5 mm powder, mix the powder with 700 g of a 2 wt% sodium alginate solution, stir for 20 min, let stand at room temperature for 1 h, and vacuum dry at 70 °C for 12 h to obtain the aluminosilicate solid waste heavy metal adsorbent.

[0037] Among them, the preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve 60 g of catechol in 900 mL of an aqueous solution of 25% ethanol, and then add the composite solvent to obtain the modified solution; The preparation method of the composite solvent is as follows: Dissolve 30 g of sorbic acid in 600 mL of absolute ethanol, add 6 g of potassium sorbate and stir evenly to obtain a mixed solution. Dissolve 150 g of tannic acid in 6 L of deionized water and add it to the mixed solution to obtain the composite solvent.

[0038] S2. Mix 500 g of sawdust biochar with 7.5 kg of the modified solution, stir magnetically at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0039] The preparation method of the sawdust biochar is as follows: After drying the sawdust, pyrolyze the sawdust in a nitrogen atmosphere at 400 °C for 2 h, and cool to room temperature to obtain the sawdust biochar.

[0040] Among them, the preparation method of the modified aluminosilicate solid waste includes: Mix 40 g of sodium silicate, 60 g of calcium hydroxide, 100 g of fly ash, and 100 g of blast furnace slag, stir, then add 6 g of cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain the modified aluminosilicate solid waste.

[0041] Example 4 The aluminosilicate solid waste heavy metal adsorbent provided in this example includes 500 g of modified aluminosilicate solid waste, 200 g of modified sawdust biochar, and 14 g of sodium alginate.

[0042] The preparation method of the aluminosilicate solid waste heavy metal adsorbent is as follows: Mix 500 g of modified aluminosilicate solid waste with 200 g of modified sawdust biochar, grind them into 0.5 mm powder, mix the powder with 700 g of 2 wt% sodium alginate solution, stir for 20 min, let it stand at room temperature for 1 h, and vacuum dry at 80 °C for 6 h to obtain the aluminosilicate solid waste heavy metal adsorbent.

[0043] Among them, the preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve 70 g of catechol in 1.26 L of an aqueous solution of 25% ethanol, and then add the composite solvent to obtain the modified solution; The preparation method of the composite solvent is as follows: Dissolve 35 g of sorbic acid in 700 mL of absolute ethanol, add 7 g of potassium sorbate and stir evenly to obtain a mixed solution. Dissolve 70 g of tannic acid in 2.8 L of deionized water and then add it to the mixed solution to obtain the composite solvent.

[0044] S2. Mix 300 g of sawdust biochar with 4.5 kg of the modified solution, stir magnetically at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0045] The preparation method of the sawdust biochar is as follows: After drying the sawdust, pyrolyze the sawdust in a nitrogen atmosphere at 600 °C for 2 h, and cool to room temperature to obtain the sawdust biochar.

[0046] Among them, the preparation method of the modified aluminosilicate solid waste includes: Mix 120 g of sodium silicate, 60 g of calcium hydroxide and 300 g of blast furnace slag, stir, then add 24 g of cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain modified aluminosilicate solid waste.

[0047] Example 5 The heavy metal adsorbent of aluminosilicate solid waste provided in this example comprises 400 g of modified aluminosilicate solid waste, 400 g of modified sawdust biochar and 16 g of sodium alginate.

[0048] The preparation method of the heavy metal adsorbent of aluminosilicate solid waste is as follows: Mix 400 g of modified aluminosilicate solid waste with 400 g of modified sawdust biochar, grind them into 0.5 mm powder, mix the powder with 800 g of sodium alginate solution with a concentration of 2 wt%, stir for 20 min, let it stand at room temperature for 1 h, and vacuum dry at 60 °C for 8 h to obtain the heavy metal adsorbent of aluminosilicate solid waste.

[0049] Among them, the preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve 150 g of catechol in 3 L of an aqueous solution of ethanol with a concentration of 25%, then add the composite solvent to obtain the modified solution; The preparation method of the composite solvent is as follows: Dissolve 75 g of sorbic acid in 1.5 L of absolute ethanol, add 15 g of potassium sorbate and stir evenly to obtain a mixed solution, dissolve 75 g of tannic acid in 3 L of deionized water and then add it to the mixed solution to obtain the composite solvent.

[0050] S2. Mix 500 g of sawdust biochar with 7.5 kg of the modified solution, magnetically stir at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0051] Among them, the preparation method of the sawdust biochar is as follows: Dry the sawdust, pyrolyze the sawdust in a nitrogen atmosphere at 500 °C for 2 h, and cool to room temperature to obtain the sawdust biochar.

[0052] Among them, the preparation method of the modified aluminosilicate solid waste includes: Mix 60 g of sodium silicate, 120 g of calcium hydroxide and 300 g of water quenched slag, stir, then add 15 g of cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain the modified aluminosilicate solid waste.

[0053] Comparative Example 1 The heavy metal adsorbent of aluminosilicate solid waste provided in this comparative example is different from that in Example 1 in that the modified aluminosilicate solid waste in the raw materials is replaced with 240 g of untreated fly ash and 160 g of water quenched slag.

[0054] Comparative Example 2 The aluminosilicate solid waste heavy metal adsorbent provided in this comparative example is different from that in Example 1 in that the preparation method of the modified aluminosilicate solid waste includes: Mix 90 g of sodium silicate, 90 g of calcium hydroxide, 180 g of fly ash, and 120 g of water quenched slag, and continue to stir at 60 °C for 30 min after stirring evenly to obtain the modified aluminosilicate solid waste.

[0055] Comparative Example 3 The aluminosilicate solid waste heavy metal adsorbent provided in this comparative example is different from that in Example 1 in that the modified sawdust biochar is replaced with an equal amount of sawdust biochar, that is, it is not modified.

[0056] Comparative Example 4 The aluminosilicate solid waste heavy metal adsorbent provided in this comparative example is different from that in Example 1 in that it includes 400 g of modified aluminosilicate solid waste and 300 g of modified sawdust biochar, that is, sodium alginate is not added in this comparative example.

[0057] The adsorption efficiency of the adsorbents prepared in Examples 1-5 and Comparative Examples 1-4 was tested, specifically for the application of the adsorbents in the adsorption of oxygen-containing anions of lead and oxygen-containing anions of arsenic.

[0058] Prepare a 10 mg / L solution of PbO 3 - , AsO 3 3- solution, the adsorbent dosage is 0.1 g / L, and the adsorption efficiency of each example and comparative example at 30 min was tested. The test results are shown in Table 1.

[0059] Table 1

[0060] From the comparison between Examples 4 and 5 and Example 1, the adsorbents prepared in Examples 4 and 5 have a lower adsorption rate for arsenic oxygen anions and lead negative oxygen ions compared to Example 1. From the comparison between Comparative Examples 1 and 2 and Example 1, the adsorption rate of the adsorbents prepared in Comparative Examples 1 and 2 decreased compared to Example 1; Comparative Example 3 used unmodified biochar, and its adsorption rate for arsenic oxygen anions was less than 60% of that in Example 1; in Comparative Example 4, sodium alginate was not added, and the prepared adsorbent showed poor formability during the adsorption process, that is, the structure was relatively loose, and at the same time, the adsorption efficiency decreased compared to Example 1, but the decrease amplitude was lower than that of Comparative Examples 1-3.

[0061] Figure 2 SEM photograph of the adsorbent prepared for Example 1Figure 3 The Zeta potential diagram of the adsorbent prepared in Example 1 shows that after modification, the isoelectric point of the adsorbent rises above pH 11, showing a high surface positive charge density in a wide pH range, laying a foundation for the efficient adsorption of arsenic and lead anionic oxygen ions.

[0062] Furthermore, as shown in Figure 4 and Figure 5 the adsorbent prepared in Example 1 shows outstanding adsorption response ability and adsorption capacity for PbO 3 - and AsO 3 3- When the dosage of the adsorbent is 0.1 g / L and the concentrations of PbO 3 - and AsO 3 3- are both 10 mg / L, the adsorption rates can reach 81.96% and 95.15% respectively in 8 min, and the adsorption efficiencies are 94.47% and 97.90% respectively in 52 min.

[0063] To further verify whether the adsorbent prepared in the example can still maintain good adsorption efficiency in a relatively extreme environment, the following tests were carried out: on the basis of pH 7, the above 10 mg / L PbO 3 - , AsO 3 3- solution was used as experimental group 1, and experimental group 2 in a high-salt and high-hardness environment was provided: 10 mg / L PbO 3 - , AsO 3 3- solution, the NaCl concentration was 2 g / L, the CaCl 2 concentration was 20 mM, the MgCl 2 concentration was 10 mM, and two blank solutions were used as blank control groups (without adding the adsorbent, and the rest of the operations were the same as those of experimental group 1 and experimental group 2 respectively, corresponding to control group 1 and control group 2). The blank control groups were used to correct the changes in heavy metal ion concentrations caused by non-adsorption factors.

[0064] The adsorbent used was the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1, and the dosage was 0.1 g / L. The test results of the adsorption efficiency at 30 min are shown in Table 2.

[0065] Table 2

[0066] It should be noted that the AsO 33- and PbO 3 - The error rate of the change in ion concentration is within 1%, that is, the change rate of the initial concentration (10 mg / L) and the concentration after 30 min is within 1%, and interferences such as container adsorption and detection error can be excluded.

[0067] As can be seen from Table 2, in the simulated high-salt and high-hardness environment, interfering ions such as Cl - and Ca 2+ and Mg 2+ will compete with the surface active sites of the adsorbent, but the adsorption efficiency of AsO 3 3- does not decrease significantly, and the decrease in the adsorption rate of AsO 3 3- is significantly lower than the adsorption rate of PbO 3 - , indicating that the adsorption of PbO 3 - is greatly affected by interferences.

[0068] After modification treatment, the adsorbent prepared in the embodiment has the characteristics of strong adsorption response ability, can efficiently treat trace-concentration and high-concentration polluted water bodies, has low cost, can maintain high-efficiency adsorption performance within a wide pH range (3 - 10), and has no risk of dissolution, ensuring long-term stable operation; in a complex water quality environment (such as high-salt and high-hardness water bodies), it can still preferentially adsorb arsenic ions, has strong anti-interference ability, can be applied to industrial wastewater treatment and heavy metal contaminated site remediation and other fields, and is suitable for the advanced treatment of complex water bodies such as mine drainage, metallurgical wastewater, and electroplating wastewater.

[0069] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An aluminosilicate solid waste heavy metal adsorbent, characterized in that: In terms of mass fraction, it includes: 30-50 parts of modified aluminosilicate solid waste, 20-40 parts of modified sawdust biochar and 1.2-1.6 parts of sodium alginate; The preparation method of the modified sawdust biochar comprises: S1. preparing a modified solution: dissolving catechol in a 25% ethanol aqueous solution, and adding a composite solvent to obtain a modified solution, wherein the mass volume ratio of catechol to the 25% ethanol aqueous solution is 1 g: (15-20) mL; S2. Mix the sawdust biochar and the modified solution in a mass ratio of 1:15, stir magnetically at room temperature for 1 hour, and obtain the modified sawdust biochar after filtering and drying.

2. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, characterized in that: The composite solvent comprises sorbic acid, potassium sorbate and tannic acid in a mass ratio of 1:0.2:(0-5), and the preparation method of the composite solvent comprises: After dissolving sorbic acid in anhydrous ethanol, potassium sorbate is added and stirred evenly to obtain a mixed solution, and tannic acid is dissolved in deionized water and added to the mixed solution to obtain a composite solvent, wherein the mass volume ratio of sorbic acid to anhydrous ethanol is 1g:20mL, and the mass volume ratio of tannic acid to deionized water is 1g:40mL.

3. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, characterized in that: The method for preparing the sawdust biochar comprises: After drying the sawdust, the sawdust was pyrolyzed at 400-600°C in a nitrogen atmosphere for 2 h, and then cooled to room temperature to obtain sawdust biochar.

4. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, characterized in that: The preparation method of the modified aluminosilicate solid waste comprises: Sodium silicate, calcium hydroxide and aluminosilicate solid waste are mixed in a mass ratio of (0.2-0.4):(0.2-0.4):1, and then cetyltrimethylammonium bromide is added after stirring. After continuing to stir at 60°C for 30 minutes, modified aluminosilicate solid waste is obtained, and the mass of the cetyltrimethylammonium bromide is 3-8% of the mass of the aluminosilicate solid waste.

5. The aluminosilicate solid waste heavy metal adsorbent according to claim 4, characterized in that: The aluminosilicate solid waste includes at least one of fly ash, water-quenched slag and blast furnace slag.

6. A method for preparing an aluminosilicate solid waste heavy metal adsorbent according to any one of claims 1 to 5, characterized in that: It includes the following steps: The modified aluminosilicate solid waste and the modified sawdust biochar were mixed and ground into 0.5 mm powder. The powder was mixed with 2 wt % sodium alginate solution in a mass ratio of 1:(0.8~2), stirred for 20 min, allowed to stand at room temperature for 1~2 h, and dried to obtain an aluminosilicate solid waste heavy metal adsorbent.

7. The preparation method according to claim 6, characterized in that: The drying conditions are vacuum drying at 60-80° C. for 6-12 hours.

8. Use of the aluminosilicate solid waste heavy metal adsorbent as claimed in any one of claims 1 to 5 in the adsorption of oxygen-containing anions of lead and arsenic.

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