An aluminosilicate solid waste heavy metal adsorbent, its preparation method and application

Abstract

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. By mass, the aluminosilicate solid waste heavy metal adsorbent comprises 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. Prepare a modified solution: dissolve catechol in an aqueous solution of 25% ethanol, and then add a composite solvent to obtain a modified solution; 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.

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, a preparation method thereof, and an application thereof. 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 PbO3 - , Pb(OH) 3- ) and oxygen-containing anions of arsenic (AsO3 3- , AsO4 3- ) in water are becoming increasingly prominent; these pollutants mainly come from non-ferrous metal smelting, electroplating, chemical industry, pesticide production, and mine wastewater. The oxygen-containing anions of lead and arsenic in water are easily combined with particulate matters and colloids, 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 precipitates such as Pb(OH)2 and sparingly soluble salts such as Ca3(AsO4)2, but this easily generates 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, has a high cost, and poor adaptability to complex water quality; traditional adsorption materials such as activated carbon and zeolite have problems such as 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 adsorption material has important environmental and social benefits. Summary of the Invention

[0005] This application provides an aluminosilicate solid waste heavy metal adsorbent, a preparation method thereof, and an application thereof 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:

[0007] 30 - 50 parts of modified aluminosilicate solid waste, 20 - 40 parts of modified sawdust biochar, and 1.2 - 1.6 parts of sodium alginate;

[0008] The preparation method of the modified sawdust biochar includes:

[0009] S1. Prepare a 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;

[0010] S2. Mix the sawdust biochar and the modified solution at a mass ratio of 1:15, magnetically stir for 1 h at room temperature, filter and dry to obtain the modified sawdust biochar.

[0011] Preferably, the composite solvent comprises sorbic acid, potassium sorbate and tannic acid at a mass ratio of 1:0.2:(0 - 5), and the preparation method of the composite solvent comprises:

[0012] Dissolve sorbic acid in absolute ethanol, add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water and add it to the mixed solution to obtain the composite solvent, wherein 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.

[0013] Preferably, the preparation method of the sawdust biochar comprises:

[0014] 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.

[0015] Preferably, the preparation method of the modified aluminosilicate solid waste comprises:

[0016] Mix sodium silicate, calcium hydroxide and aluminosilicate solid waste at 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, wherein the mass of cetyltrimethylammonium bromide is 3 - 8% of the mass of the aluminosilicate solid waste.

[0017] Preferably, the aluminosilicate solid waste comprises at least one of fly ash, water - quenched slag, and blast furnace slag.

[0018] Second, a preparation method of the aluminosilicate solid - waste heavy - metal adsorbent as described above is provided, which comprises the following steps:

[0019] Mix the modified aluminosilicate solid waste and the modified sawdust biochar, grind them 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.

[0020] Preferably, the drying conditions are vacuum drying at 60 - 80 °C for 6 - 12 h.

[0021] Third, 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.

[0022] The beneficial effects brought by the technical solution provided in this application include:

[0023] 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 oxygen-containing anions of arsenic. As a biomass waste, sawdust biochar obtains charge properties and coordination abilities after surface modification, and realizes the directional capture of target pollutants (oxygen-containing anions of lead and oxygen-containing anions of arsenic) through chemical coordination and electrostatic adsorption, without introducing additional pollutants. While effectively removing oxygen-containing anions of lead and oxygen-containing anions of arsenic in water, it meets the environmental protection benefits and economic value of "treating waste with waste". Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of 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.

[0025] Figure 1 It is the preparation flow chart of the modified sawdust biochar provided by this application;

[0026] Figure 2 It is the SEM photograph of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided by this application;

[0027] Figure 3 It is the Zeta potential diagram of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided by this application;

[0028] Figure 4 It is the adsorption efficiency diagram of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided by this application for PbO3 - ;

[0029] Figure 5 It is the adsorption efficiency diagram of the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1 provided by this application for AsO3 3- ; Detailed Embodiments

[0030] 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 belong to the scope protected by this application.

[0031] 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.

[0032] Among them, the preparation method of the modified sawdust biochar includes:

[0033] 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-volume ratio of catechol to the aqueous solution of 25% ethanol is 1 g:(15-20) mL;

[0034] S2. Mix the sawdust biochar and 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.

[0035] Among them, the aqueous solution of 25% ethanol means that the volume ratio of ethanol to water is 1:4.

[0036] Further, the above 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:

[0037] Dissolve sorbic acid in absolute ethanol in a mass-volume ratio of 1:20, then add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water in a mass-volume ratio of 1:40 and then add it to the mixed solution to obtain the composite solvent.

[0038] Specifically, dissolve sorbic acid in absolute ethanol, then 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-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.

[0039] Among them, the preparation method of the sawdust biochar includes:

[0040] After drying the sawdust, pyrolyze the sawdust at 400 - 600 °C under a nitrogen atmosphere for 2 h, and obtain sawdust biochar after cooling to room temperature.

[0041] In some embodiments, the preparation method of the modified aluminosilicate solid waste includes:

[0042] 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, where the mass of cetyltrimethylammonium bromide is 3 - 8% of the mass of the aluminosilicate solid waste.

[0043] In some embodiments, the aluminosilicate solid waste includes at least one of fly ash, water - quenched slag, and blast furnace slag.

[0044] The preparation method of the heavy - metal adsorbent from aluminosilicate solid waste provided in this application includes the following steps:

[0045] After mixing 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 in a mass ratio of 1:(0.8 - 2), stir for 20 min, let it stand at room temperature for 1 - 2 h, and obtain the heavy - metal adsorbent from aluminosilicate solid waste after drying.

[0046] 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.

[0047] Example 1

[0048] The heavy - metal adsorbent from 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.

[0049] The preparation method of the heavy - metal adsorbent from aluminosilicate solid waste is:

[0050] After mixing 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 obtain the heavy - metal adsorbent from aluminosilicate solid waste after vacuum drying at 60 °C for 8 h.

[0051] Among them, the preparation method of the modified sawdust biochar includes:

[0052] 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 a composite solvent to obtain the modified solution;

[0053] The preparation method of the composite solvent is as follows:

[0054] Dissolve 100 g of sorbic acid in 2 L of absolute ethanol, then 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 then add it to the mixed solution to obtain the composite solvent.

[0055] S2. Mix 400 g of sawdust biochar with 6 kg of the modified solution, magnetically stir at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0056] The preparation method of the sawdust biochar is as follows:

[0057] 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.

[0058] Among them, the preparation method of the modified aluminosilicate solid waste includes:

[0059] Mix 90 g of sodium silicate, 90 g of calcium hydroxide, 180 g of fly ash, and 120 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.

[0060] Example 2

[0061] The difference from Example 1 is that in step S1, the preparation method of the composite solvent is as follows:

[0062] Dissolve 100 g of sorbic acid in 2 L of absolute ethanol, then add 20 g of potassium sorbate and stir evenly to obtain a mixed solution. Continue to add 4 L of deionized water to the mixed solution to obtain the composite solvent.

[0063] Example 3

[0064] 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.

[0065] The preparation method of the aluminosilicate solid waste heavy metal adsorbent is as follows:

[0066] 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 2 wt% sodium alginate solution, stir for 20 min, let it 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.

[0067] Among them, the preparation method of the modified sawdust biochar includes:

[0068] S1. Preparation of modified solution: After dissolving 60 g of catechol in 900 mL of an aqueous solution of ethanol with a concentration of 25%, a composite solvent was added to obtain a modified solution;

[0069] The preparation method of the composite solvent is as follows:

[0070] After dissolving 30 g of sorbic acid in 600 mL of absolute ethanol, 6 g of potassium sorbate was added and stirred evenly to obtain a mixed solution. After dissolving 150 g of tannic acid in 6 L of deionized water, it was added to the mixed solution to obtain a composite solvent.

[0071] 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 modified sawdust biochar.

[0072] The preparation method of the sawdust biochar is as follows:

[0073] After drying the sawdust, pyrolyze the sawdust in a nitrogen atmosphere at 400 °C for 2 h, and cool to room temperature to obtain sawdust biochar.

[0074] Among them, the preparation method of the modified aluminosilicate solid waste includes:

[0075] Mix 40 g of sodium silicate, 60 g of calcium hydroxide, 100 g of fly ash, and 100 g of blast furnace slag, stir, and then add 6 g of cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain modified aluminosilicate solid waste.

[0076] Example 4

[0077] 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.

[0078] The preparation method of the aluminosilicate solid waste heavy metal adsorbent is as follows:

[0079] Mix 500 g of modified aluminosilicate solid waste with 200 g of modified sawdust biochar, grind it into a powder of 0.5 mm, mix the powder with 700 g of a sodium alginate solution with a concentration of 2 wt%, stir for 20 min, 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.

[0080] Among them, the preparation method of the modified sawdust biochar includes:

[0081] S1. Preparation of modified solution: After dissolving 70 g of catechol in 1.26 L of an aqueous solution of ethanol with a concentration of 25%, a composite solvent was added to obtain a modified solution;

[0082] The preparation method of the composite solvent is as follows:

[0083] After dissolving 35 g of sorbic acid in 700 mL of absolute ethanol, 7 g of potassium sorbate was added and stirred evenly to obtain a mixed solution. After dissolving 70 g of tannic acid in 2.8 L of deionized water, it was added to the mixed solution to obtain a composite solvent.

[0084] S2. Mix 300 g of sawdust biochar with 4.5 kg of the modified solution, magnetically stir at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

[0085] The preparation method of the sawdust biochar is as follows:

[0086] 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.

[0087] Among them, the preparation method of the modified aluminosilicate solid waste includes:

[0088] Mix 120 g of sodium silicate, 60 g of calcium hydroxide and 300 g of blast furnace slag, stir and then add 24 g of cetyltrimethylammonium bromide, and continue to stir at 60 °C for 30 min to obtain the modified aluminosilicate solid waste.

[0089] Example 5

[0090] The aluminosilicate solid waste heavy metal adsorbent provided in this example includes 400 g of modified aluminosilicate solid waste, 400 g of modified sawdust biochar and 16 g of sodium alginate.

[0091] The preparation method of the aluminosilicate solid waste heavy metal adsorbent is as follows:

[0092] After mixing 400 g of modified aluminosilicate solid waste with 400 g of modified sawdust biochar, grind it into a powder of 0.5 mm. After mixing the powder with 800 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 aluminosilicate solid waste heavy metal adsorbent.

[0093] Among them, the preparation method of the modified sawdust biochar includes:

[0094] S1. Prepare the modified solution: After dissolving 150 g of catechol in an aqueous solution of 3 L of ethanol with a concentration of 25%, add the composite solvent to obtain the modified solution;

[0095] The preparation method of the composite solvent is as follows:

[0096] After dissolving 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. After dissolving 75 g of tannic acid in 3 L of deionized water, add it to the mixed solution to obtain the composite solvent.

[0097] 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.

[0098] The preparation method of the sawdust biochar is as follows:

[0099] 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.

[0100] Among them, the preparation method of the modified aluminosilicate solid waste includes:

[0101] 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.

[0102] Comparative Example 1

[0103] The aluminosilicate solid waste heavy metal adsorbent 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.

[0104] Comparative Example 2

[0105] 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:

[0106] Mix 90 g of sodium silicate, 90 g of calcium hydroxide, 180 g of fly ash and 120 g of water quenched slag, stir evenly, and continue to stir at 60 °C for 30 min to obtain the modified aluminosilicate solid waste.

[0107] Comparative Example 3

[0108] 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.

[0109] Comparative Example 4

[0110] 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.

[0111] Test the adsorption efficiency of the adsorbents prepared in Examples 1-5 and Comparative Examples 1-4, specifically for the application of the adsorbents in the adsorption of oxygen-containing anions of lead and oxygen-containing anions of arsenic.

[0112] Prepare a PbO3 solution with a concentration of 10 mg / L - and AsO3 3- solution. The dosage of the adsorbent is 0.1 g / L, and the adsorption efficiency of each example and comparative example at 30 min is tested. The test results are shown in Table 1

[0113] Table 1

[0114]

[0115] 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 arsenite anions and lead oxyanions compared to Example 1. From the comparison between Comparative Examples 1 and 2 and Example 1, the adsorption rates of the adsorbents prepared in Comparative Examples 1 and 2 are lower than that of Example 1. In Comparative Example 3, unmodified biochar is used, and its adsorption rate for arsenite anions is less than 60% of that in Example 1. In Comparative Example 4, sodium alginate is not added, and the adsorbent prepared shows poor adsorbent formability during the adsorption process, that is, the structure is relatively loose, and at the same time, the adsorption efficiency is lower than that in Example 1, but the decrease amplitude is lower than that in Comparative Examples 1 - 3

[0116] Figure 2 is the SEM photograph of the adsorbent prepared in Example 1 Figure 3 is the Zeta potential diagram of the adsorbent prepared in Example 1. It can be known 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 arsenite and lead oxyanions

[0117] Furthermore, as shown in Figure 4 and Figure 5 the adsorbent prepared in Example 1 shows outstanding adsorption response ability and adsorption capacity for PbO3 - and AsO3 3- When the dosage of the adsorbent is 0.1 g / L and the concentrations of PbO3 - and AsO3 3- are both 10 mg / L, the adsorption rates can reach 81.96% and 95.15% respectively at 8 min, and the adsorption efficiencies are 94.47% and 97.90% respectively at 52 min

[0118] To further verify whether the adsorbent prepared in the example can still maintain a good adsorption efficiency in a relatively extreme environment, the following test is carried out: based on pH = 7, the above 10 mg / L PbO3 - and AsO3 3- solution is used as Experimental Group 1, and Experimental Group 2 in a high - salt and high - hardness environment is provided: 10 mg / L PbO3- 、AsO3 3- solution with an NaCl concentration of 2 g / L, a CaCl2 concentration of 20 mM, and a MgCl2 concentration of 10 mM, and two blank solutions as blank control groups (without adding adsorbent, and the rest of the operations are the same as those in experimental group 1 and experimental group 2, corresponding to control group 1 and control group 2 respectively), where the blank control groups are used to correct the changes in heavy metal ion concentrations caused by non-adsorption factors.

[0119] The adsorbent used is the aluminosilicate solid waste heavy metal adsorbent prepared in Example 1, and the dosage is 0.1 g / L. The test results of the adsorption efficiency at 30 min are shown in Table 2.

[0120] Table 2

[0121]

[0122] It should be noted that the error rates of the changes in the AsO3 3- and PbO3 - ion concentrations in control group 1 and control group 2 are both within 1%, that is, the change rate of the initial concentration (10 mg / L) and the concentration after 30 min is within 1%, which can exclude interferences such as container adsorption and detection errors.

[0123] As can be seen from Table 2, in the simulated high-salt and high-hardness environment, interfering ions such as Cl - , Ca 2+ , and Mg 2+ will compete with the surface active sites of the adsorbent, but the decrease in the adsorption efficiency of AsO3 3- is not significant, and the decrease in the adsorption rate of AsO3 3- is significantly lower than that of PbO3 - , indicating that the adsorption of PbO3 - is more affected by interference.

[0124] After modification treatment, the adsorbent prepared in the example 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 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, and 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.

[0125] 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 rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. An aluminosilicate solid waste heavy metal adsorbent, characterized in that, By mass parts, 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 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 aluminosilicate solid waste includes at least one of fly ash, water quenched slag, and blast furnace slag; The preparation method of the modified sawdust biochar includes: S1. Prepare the modified solution: Dissolve catechol in an aqueous solution of 25% ethanol, then add the composite solvent to obtain the modified solution. The mass - to - volume ratio of catechol to the aqueous solution of 25% ethanol is 1 g:15 - 20 mL. The composite solvent includes sorbic acid, potassium sorbate, and tannic acid in a mass ratio of 1:0.2:0 - 5. The 25% ethanol aqueous solution means the volume ratio of ethanol to water is 1:4; S2. Mix the sawdust biochar with the modified solution in a mass ratio of 1:15, magnetically stir at room temperature for 1 h, filter and dry to obtain the modified sawdust biochar.

2. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, wherein: The preparation method of the composite solvent includes: Dissolve sorbic acid in absolute ethanol, then add potassium sorbate and stir evenly to obtain a mixed solution. Dissolve tannic acid in deionized water and add it to the mixed solution to obtain the composite solvent. 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.

3. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, wherein: 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.

4. The aluminosilicate solid waste heavy metal adsorbent according to claim 1, wherein: The mass of the cetyltrimethylammonium bromide is 3 - 8% of the mass of the aluminosilicate solid waste.

5. A preparation method of the aluminosilicate solid waste heavy metal adsorbent according to any one of claims 1-4, characterized in that, It includes the following steps: Mix the modified aluminosilicate solid waste and the modified sawdust biochar, grind them 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 aluminosilicate solid waste heavy metal adsorbent.

6. The preparation method according to claim 5, wherein: The drying condition is vacuum drying at 60 - 80 °C for 6 - 12 h.

7. Application of the aluminosilicate solid waste heavy metal adsorbent according to any one of claims 1 - 4 in the adsorption of oxygen - containing anions of lead and oxygen - containing anions of arsenic.

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