Adsorbent for sewage treatment and preparation method thereof

Abstract

The invention relates to the technical field of sewage treatment, in particular to an adsorbent for sewage treatment and a preparation method thereof. The adsorbent is prepared from the following raw materials in parts by weight: 50-70 parts of an additive, 20-30 parts of activated carbon, 5-10 parts of polyacrylamide, 3-8 parts of ammonium bicarbonate, 5-15 parts of a functional aid and 80-120 parts of deionized water. According to the invention, the additive takes oyster shell powder as an adsorption matrix, the oyster shell powder is compounded with a reaction material containing organic phosphonic acid, complex groups in the reaction material can fix pollutants on the surface of the additive to realize synergistic interaction of physical adsorption and chemical complexing, and the functional additive is composed of composite powder and modified nano silicon dioxide. The composite powder adsorbs pollutants through hydrogen bonds and complexation of active functional groups and strengthens capturing and fixing effects on organic pollutants, and the prepared adsorbent has physical adsorption and chemical bonding functions and can effectively remove organic matters and heavy metal ions in sewage.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an adsorbent for wastewater treatment and its preparation method. Background Technology

[0002] Adsorbents for wastewater treatment are a class of highly efficient materials that capture pollutants in water through physical or chemical processes. Common types include activated carbon, zeolite, modified clay, and emerging materials such as biochar and resin. With industrial development and the increase in domestic sewage discharge, the composition of pollutants in wastewater is becoming increasingly complex, encompassing various harmful substances such as organic pollutants and heavy metal ions, posing a serious threat to the ecological environment and human health. High-efficiency wastewater purification has become an urgent need in the environmental protection field. Adsorbents have become one of the mainstream technologies for wastewater treatment due to their ease of operation and moderate cost. However, adsorbents still face many technical bottlenecks.

[0003] In existing technologies, adsorbents mostly rely on single porous materials and primarily rely on physical adsorption. This results in insufficient targeted capture capabilities for multiple pollutants in complex systems, leading to limited adsorption capacity. While some modified adsorbents improve performance through simple doping, they suffer from uneven component dispersion. Therefore, this invention provides an adsorbent for wastewater treatment and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an adsorbent for wastewater treatment and its preparation method. The adsorbent prepared by this invention not only has good adsorption performance, but also excellent stable chemical binding performance, which effectively improves the wastewater treatment efficiency of the adsorbent.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, an adsorbent for wastewater treatment comprises the following raw materials in parts by weight: 50-70 parts additives, 20-30 parts activated carbon, 5-10 parts polyacrylamide, 3-8 parts ammonium bicarbonate, 5-15 parts functional additives, and 80-120 parts deionized water. The raw materials for the additive include oyster shell powder, citric acid solution, and reactants; The raw materials for the functional additives include composite powder and modified nano-silica.

[0006] Further, the additive is prepared by the following method: oyster shell powder is transferred to a muffle furnace and calcined at 600℃ for 1.5-2.5h, cooled, and the calcined oyster shell powder is mixed with citric acid solution at a solid-liquid ratio of 1g:(9-11)mL, reacted at 60℃ for 1.5-2.5h, filtered, and the filter residue is washed with deionized water until neutral, dried, and acid-washed oyster shell powder is obtained. The acid-washed oyster shell powder is mixed with the reaction material at a mass ratio of 1:(0.08-0.15), and 2-3 times the mass of deionized water of the acid-washed oyster shell powder is added, reacted at 70-80℃ for 2-4h, filtered, and the filter residue is washed with deionized water 3 times, dried, ground through a 200-mesh sieve to obtain the additive, wherein the concentration of the citric acid solution is 1.0mol / L.

[0007] Further, the reactant is prepared by the following method: the additive powder and deionized water are mixed at a mass ratio of 1:(3.5-4.5) to obtain a first mixture. Under nitrogen protection, the first mixture is added dropwise to a ferrous sulfate solution at 40°C. After the addition is complete, the mixture is allowed to mature for 1 hour to obtain the reactant. The volume ratio of the first mixture to the ferrous sulfate solution is 1:(2.3-2.5), and the concentration of the ferrous sulfate solution is 0.4-0.6 mol / L.

[0008] Further, the additive powder is prepared by the following method: itaconic acid and aminotrimethylenephosphonic acid are added to a reaction vessel at a molar ratio of 1:1 to obtain reactants. Deionized water, at 1-2 times the total mass of the reactants, is added, and the mixture is reacted at 80-90℃ for 4.5-5.5 hours. After the reaction is complete, the mixture is cooled to obtain a second mixture. The second mixture is poured into acetone at 4-6 times its volume, filtered, and the residue is washed twice with acetone and dried to obtain an intermediate product. Sodium alginate powder is then mixed with the intermediate product... Mix sodium alginate at a mass ratio of 1:(0.3-0.5), add 20 times the mass of deionized water, stir at 300-500 rpm for 30-60 min, add 1% of the mass of sodium alginate in potassium persulfate, and react in a water bath at 60-70℃ for 4 h to obtain a third mixture. Add the third mixture to anhydrous ethanol at 3-5 times its volume, filter and collect the residue, wash the residue three times with anhydrous ethanol, dry it, grind it through a 200-mesh sieve to obtain the additive powder.

[0009] Further, the functional additive is prepared by the following method: the composite powder and modified nano-silica are mixed at a mass ratio of (2.5-3.5):2 to obtain a mixture. The mixture is then mixed with a 50% volume concentration ethanol solution at a solid-liquid ratio of 1g:(7-9)mL and transferred to a planetary ball mill. The mixture is ball-milled at a speed of 300-500rpm for 2h to obtain a composite dispersion. The composite dispersion is then transferred to a subcritical reactor, and a mixed gas is introduced. The mixture is treated at 0.3MPa for 10min, followed by a reaction at 120℃ and 1.5MPa at a speed of 250rpm for 90min. After the reaction is completed, the mixture is cooled, depressurized, and the reaction solution is removed. The mixture is then centrifuged to separate the precipitate, which is collected. The precipitate is washed with deionized water until neutral, dried, and pulverized to 120 mesh to obtain the functional additive.

[0010] Further, the composite powder is prepared by the following method: after drying Eucommia ulmoides leaves, it is pulverized and passed through a 200-mesh sieve to obtain Eucommia ulmoides leaf powder. The Eucommia ulmoides leaf powder is mixed with lignin phenol at a mass ratio of (2.5-3.5):1. Deionized water is added, and the solid-liquid ratio is controlled at 1g:(4-6)mL. The pH is adjusted to 7.0-7.5 with 10% sodium hydroxide. The mixture is stirred at 300rpm for 2h in a water bath at 55-65℃. The mixture is then centrifuged to separate the precipitate. The precipitate is washed three times with deionized water and dried at 80℃ for 4h to obtain the composite powder.

[0011] Furthermore, the modified nano-silica is prepared by the following method: nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide are added to a supercritical reactor, carbon dioxide is introduced, and the reaction is carried out at 8 MPa and 40°C at a speed of 400 rpm for 2 hours. The pressure is then released to atmospheric pressure, the product is taken out, dried, pulverized and passed through a 200-mesh sieve to obtain modified nano-silica.

[0012] Furthermore, the mass ratio of the nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide is 100:(7-9):(0.3-0.35).

[0013] Furthermore, the mixed gas is composed of perfluorooctylethylene and nitrogen in a volume ratio of (4-5):1.

[0014] Secondly, the present invention provides a method for preparing an adsorbent for wastewater treatment, comprising the following steps: Step 1: Place the additives, activated carbon, polyacrylamide and ammonium bicarbonate in a high-speed mixer and stir at 800-1200 rpm for 10-15 minutes to obtain a premix. Add deionized water to the premix and knead to form wet granules with a particle size of 2-4 mm. Step 2: Dilute the functional additive with 50% of its volume of deionized water, spray it evenly onto the surface of the wet particles, let it stand and solidify at 60°C for 2 hours, then heat treat it at 110°C for 1 hour, and then dry it at 120°C to constant weight to obtain the adsorbent for wastewater treatment.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, the additive uses oyster shell powder as the adsorption matrix and is compounded with a reactant containing organophosphonic acid. The complexing groups in the reactant can stably fix pollutants on the surface of the additive. This is because the additive powder in the reactant is polymerized with itaconic acid and aminotrimethylenephosphonic acid and then grafted with sodium alginate. Its large number of complexing groups can form stable chemical complexes with heavy metal ions in wastewater. The ferrous ions introduced during the preparation of the reactant enhance the specificity and stability of the complexation reaction, realize the synergistic effect of physical adsorption and chemical complexation, and effectively improve the capture ability and adsorption capacity of complex pollutants.

[0016] 2. In this invention, the functional additive is composed of composite powder and modified nano-silica. The composite powder prepared from Eucommia ulmoides leaf powder and lignin phenol is rich in active functional groups such as hydroxyl and phenolic hydroxyl groups. The composite powder adsorbs pollutants through hydrogen bonding and complexation of active functional groups, thereby enhancing the capture and fixation of organic pollutants. After supercritical modification with fluorosilane and tetrabutylphosphine ammonium bromide, the surface hydrophobicity and dispersibility of the modified nano-silica are significantly improved. It can not only capture pollutants through physical adsorption, but also act as a dispersion carrier to optimize the spatial distribution of the composite powder and improve the interfacial bonding between the composite powder and the modified nano-silica. While making the components uniformly dispersed, it enhances the targeted removal ability of specific pollutants.

[0017] 3. In this invention, the additive focuses on physical adsorption and chemical complexation, emphasizing the broad-spectrum capture and stable fixation of heavy metal ions and some organic pollutants. The oyster shell powder matrix provides a macroscopic adsorption framework, and the complexing groups of the reactants ensure the stability of pollutant binding. The functional additives have advantages in adsorption by active functional groups and targeted selectivity. The hydroxyl and phenolic hydroxyl groups of the composite powder can accurately capture recalcitrant organic pollutants. The hydrophobicity and dispersibility of the modified nano-silica optimize the microstructure of the adsorption system. When the two work together, the macroscopic porous structure of the additives provides an attachment and dispersion carrier for the functional additives, avoiding the aggregation of functional additives that leads to the failure of active sites. The functional additives fill the gap in the adsorption capacity of the additives for specific recalcitrant organics. Through the complementary effect of targeted adsorption and the broad-spectrum adsorption of the additives, the overall removal efficiency and stability of the adsorbent for multiple pollutants in complex wastewater are effectively improved. Attached Figure Description

[0018] Figure 1The present invention provides a flowchart of an adsorbent for wastewater treatment and its preparation method. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0021] Example 1: Preparation of the additive powder: Itaconic acid and aminotrimethylenephosphonic acid were added to a reaction vessel at a molar ratio of 1:1 to obtain reactants. Deionized water with a mass equal to 1 times the total mass of reactants was added, and the mixture was reacted at 80℃ for 4.5 h. After the reaction was completed, the mixture was cooled to obtain a second mixture. The second mixture was poured into acetone with a volume equal to 4 times its mass, filtered, and the residue was washed twice with acetone and dried to obtain an intermediate product. Sodium alginate powder was mixed with the intermediate product at a mass ratio of 1:0.3, and deionized water with a mass equal to 20 times the mass of sodium alginate was added. The mixture was stirred at 300 rpm for 30 min, and potassium persulfate with a mass equal to 1% of sodium alginate was added. The mixture was reacted in a water bath at 60℃ for 4 h to obtain a third mixture. The third mixture was added into anhydrous ethanol with a volume equal to 3 times its mass, filtered, and the residue was collected. The residue was washed three times with anhydrous ethanol, dried, and ground through a 200-mesh sieve to obtain the additive powder.

[0022] Preparation of the reaction mixture: The additive powder and deionized water were mixed at a mass ratio of 1:3.5 to obtain the first mixture. Under nitrogen protection, the first mixture was added dropwise to the ferrous sulfate solution at 40°C. After the addition was completed, the mixture was allowed to mature for 1 hour to obtain the reaction mixture. The volume ratio of the first mixture to the ferrous sulfate solution was 1:2.3, and the concentration of the ferrous sulfate solution was 0.4 mol / L.

[0023] Preparation of the additive: Oyster shell powder was transferred to a muffle furnace and calcined at 600℃ for 1.5h. After cooling, the calcined oyster shell powder was mixed with citric acid solution at a solid-liquid ratio of 1g:9mL and reacted at 60℃ for 1.5h. After filtration, the filter residue was washed with deionized water until neutral and dried to obtain acid-washed oyster shell powder. The acid-washed oyster shell powder was mixed with the reaction material at a mass ratio of 1:0.08, and twice the mass of the acid-washed oyster shell powder with deionized water was added. The mixture was reacted at 70℃ for 2h, filtered, and the filter residue was washed three times with deionized water, dried, and ground through a 200-mesh sieve to obtain the additive. The concentration of the citric acid solution was 1.0mol / L.

[0024] Preparation of composite powder: After drying Eucommia ulmoides leaves, the powder was pulverized and passed through a 200-mesh sieve. The Eucommia ulmoides leaf powder was mixed with lignin at a mass ratio of 2.5:1. Deionized water was added, and the solid-liquid ratio was controlled at 1g:4mL. The pH was adjusted to 7.0 with 10% sodium hydroxide. The mixture was stirred at 300rpm for 2 hours in a water bath at 55℃. The mixture was then centrifuged and the precipitate was collected. The precipitate was washed three times with deionized water and dried at 80℃ for 4 hours to obtain the composite powder.

[0025] Preparation of modified nano silica: Nano silica, fluorosilane, and tetrabutylphosphine ammonium bromide were added to a supercritical reactor, carbon dioxide was introduced, and the reaction was carried out at 8 MPa and 40 °C at a speed of 400 rpm for 2 h. The pressure was released to atmospheric pressure, the product was taken out, dried, pulverized and passed through a 200-mesh sieve to obtain modified nano silica.

[0026] The mass ratio of the nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide is 100:7:0.3.

[0027] Preparation of functional additives: Composite powder and modified nano-silica were mixed at a mass ratio of 2.5:2 to obtain a mixture. The mixture was then mixed with a 50% ethanol solution at a solid-liquid ratio of 1g:7mL and transferred to a planetary ball mill. The mixture was ball-milled at 300rpm for 2h to obtain a composite dispersion. The composite dispersion was then transferred to a subcritical reactor, and a mixed gas was introduced. The reactor was treated at 0.3MPa for 10min, followed by a reaction at 120℃ and 1.5MPa at 250rpm for 90min. After the reaction was completed, the reactor was cooled, depressurized, and the reaction solution was removed. The solution was then centrifuged to separate the precipitate, which was collected. The precipitate was washed with deionized water until neutral, dried, and pulverized to 120 mesh to obtain the functional additives.

[0028] The mixed gas is composed of perfluorooctylethylene and nitrogen in a volume ratio of 4:1.

[0029] Raw material preparation: 50 parts additives, 20 parts activated carbon, 5 parts polyacrylamide, 3 parts ammonium bicarbonate, 5 parts functional additives, and 80 parts deionized water.

[0030] Preparation of adsorbents for wastewater treatment: Step 1: Place the additives, activated carbon, polyacrylamide and ammonium bicarbonate in a high-speed mixer and stir at 800 rpm for 10 minutes to obtain a premix. Add deionized water to the premix and knead to form wet granules with a particle size of 2 mm. Step 2: Dilute the functional additive with 50% of its volume of deionized water, spray it evenly onto the surface of the wet particles, let it stand and solidify at 60°C for 2 hours, then heat treat it at 110°C for 1 hour, and then dry it at 120°C to constant weight to obtain the adsorbent for wastewater treatment.

[0031] Example 2: Preparation of the reaction mixture: The additive powder and deionized water were mixed at a mass ratio of 1:4 to obtain the first mixture. Under nitrogen protection, the first mixture was added dropwise to the ferrous sulfate solution at 40°C. After the addition was completed, the mixture was allowed to mature for 1 hour to obtain the reaction mixture. The volume ratio of the first mixture to the ferrous sulfate solution was 1:2.4, and the concentration of the ferrous sulfate solution was 0.5 mol / L.

[0032] Preparation of the additive powder: Itaconic acid and aminotrimethylenephosphonic acid were added to a reaction vessel at a molar ratio of 1:1 to obtain reactants. Deionized water with a mass of 1.5 times the total mass of reactants was added, and the mixture was reacted at 85°C for 5 hours. After the reaction was completed, the mixture was cooled to obtain a second mixture. The second mixture was poured into acetone with a mass of 5 times its volume, filtered, and the residue was washed twice with acetone and dried to obtain an intermediate product. Sodium alginate powder was mixed with the intermediate product at a mass ratio of 1:0.4, and deionized water with a mass of 20 times the mass of sodium alginate was added. The mixture was stirred at 400 rpm for 45 minutes. Potassium persulfate with a mass of 1% of sodium alginate was added, and the mixture was reacted in a water bath at 65°C for 4 hours to obtain a third mixture. The third mixture was added into anhydrous ethanol with a mass of 4 times its volume, filtered, and the residue was collected. The residue was washed three times with anhydrous ethanol, dried, and ground through a 200-mesh sieve to obtain the additive powder.

[0033] Preparation of the additive: Oyster shell powder was transferred to a muffle furnace and calcined at 600℃ for 2 hours. After cooling, the calcined oyster shell powder was mixed with citric acid solution at a solid-liquid ratio of 1g:10mL and reacted at 60℃ for 2 hours. After filtration, the filter residue was washed with deionized water until neutral and dried to obtain acid-washed oyster shell powder. The acid-washed oyster shell powder was mixed with the reaction material at a mass ratio of 1:0.12, and 2.5 times the mass of deionized water was added. The mixture was reacted at 75℃ for 3 hours. After filtration, the filter residue was washed with deionized water three times, dried, and ground through a 200-mesh sieve to obtain the additive. The concentration of the citric acid solution was 1.0mol / L.

[0034] Preparation of composite powder: After drying Eucommia ulmoides leaves, they were pulverized and passed through a 200-mesh sieve to obtain Eucommia ulmoides leaf powder. The Eucommia ulmoides leaf powder was mixed with lignin at a mass ratio of 3:1, and deionized water was added to control the solid-liquid ratio at 1g:5mL. The pH was adjusted to 7.5 with 10% sodium hydroxide. The mixture was stirred at 300rpm for 2h in a 60℃ water bath and centrifuged to separate the precipitate. The precipitate was washed three times with deionized water and dried at 80℃ for 4h to obtain the composite powder.

[0035] Preparation of modified nano silica: Nano silica, fluorosilane, and tetrabutylphosphine ammonium bromide were added to a supercritical reactor, carbon dioxide was introduced, and the reaction was carried out at 8 MPa and 40 °C at a speed of 400 rpm for 2 h. The pressure was released to atmospheric pressure, the product was taken out, dried, pulverized and passed through a 200-mesh sieve to obtain modified nano silica.

[0036] The mass ratio of the nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide is 100:8:0.33.

[0037] Preparation of functional additives: The composite powder and modified nano-silica were mixed at a mass ratio of 3:2 to obtain a mixture. The mixture was then mixed with a 50% ethanol solution at a solid-liquid ratio of 1g:8mL and transferred to a planetary ball mill. The mixture was ball-milled at 400rpm for 2h to obtain a composite dispersion. The composite dispersion was then transferred to a subcritical reactor, and a mixed gas was introduced. The reactor was treated at 0.3MPa for 10min, followed by a reaction at 120℃ and 1.5MPa at 250rpm for 90min. After the reaction was completed, the reactor was cooled, depressurized, and the reaction solution was removed. The solution was then centrifuged to separate the precipitate, which was collected. The precipitate was washed with deionized water until neutral, dried, and pulverized to 120 mesh to obtain the functional additives.

[0038] The mixed gas is composed of perfluorooctylethylene and nitrogen in a volume ratio of 4.5:1.

[0039] Raw material preparation: 60 parts additives, 25 parts activated carbon, 8 parts polyacrylamide, 5 parts ammonium bicarbonate, 10 parts functional additives, and 100 parts deionized water.

[0040] Preparation of adsorbents for wastewater treatment: Step 1: Place the additives, activated carbon, polyacrylamide and ammonium bicarbonate in a high-speed mixer and stir at 1000 rpm for 12 minutes to obtain a premix. Add deionized water to the premix and knead to form wet granules with a particle size of 3 mm. Step 2: Dilute the functional additive with 50% of its volume of deionized water, spray it evenly onto the surface of the wet particles, let it stand and solidify at 60°C for 2 hours, then heat treat it at 110°C for 1 hour, and then dry it at 120°C to constant weight to obtain the adsorbent for wastewater treatment.

[0041] Example 3: Preparation of the reaction mixture: The additive powder and deionized water were mixed at a mass ratio of 1:4.5 to obtain the first mixture. Under nitrogen protection, the first mixture was added dropwise to the ferrous sulfate solution at 40°C. After the addition was completed, the mixture was allowed to mature for 1 hour to obtain the reaction mixture. The volume ratio of the first mixture to the ferrous sulfate solution was 1:2.5, and the concentration of the ferrous sulfate solution was 0.6 mol / L.

[0042] Preparation of the additive powder: Itaconic acid and aminotrimethylenephosphonic acid were added to a reaction vessel at a molar ratio of 1:1 to obtain reactants. Deionized water with a mass of 2 times the total mass of reactants was added, and the mixture was reacted at 90℃ for 5.5 h. After the reaction was completed, the mixture was cooled to obtain a second mixture. The second mixture was poured into acetone with a mass of 6 times its volume, filtered, and the residue was washed twice with acetone and dried to obtain an intermediate product. Sodium alginate powder was mixed with the intermediate product at a mass ratio of 1:0.5, and deionized water with a mass of 20 times that of sodium alginate was added. The mixture was stirred at 500 rpm for 60 min, and potassium persulfate with a mass of 1% of sodium alginate was added. The mixture was reacted in a water bath at 70℃ for 4 h to obtain a third mixture. The third mixture was added to anhydrous ethanol with a mass of 5 times its volume, filtered, and the residue was collected. The residue was washed three times with anhydrous ethanol, dried, and ground through a 200-mesh sieve to obtain the additive powder.

[0043] Preparation of the additive: Oyster shell powder was transferred to a muffle furnace and calcined at 600℃ for 2.5h. After cooling, the calcined oyster shell powder was mixed with citric acid solution at a solid-liquid ratio of 1g:11mL and reacted at 60℃ for 2.5h. After filtration, the filter residue was washed with deionized water until neutral and dried to obtain acid-washed oyster shell powder. The acid-washed oyster shell powder was mixed with the reaction material at a mass ratio of 1:0.15, and three times the mass of the acid-washed oyster shell powder was added with deionized water. The mixture was reacted at 80℃ for 4h, filtered, and the filter residue was washed three times with deionized water, dried, and ground through a 200-mesh sieve to obtain the additive. The concentration of the citric acid solution was 1.0mol / L.

[0044] Preparation of composite powder: After drying Eucommia ulmoides leaves, the powder was pulverized and passed through a 200-mesh sieve. The Eucommia ulmoides leaf powder was mixed with lignin at a mass ratio of 3.5:1. Deionized water was added, and the solid-liquid ratio was controlled at 1g:6mL. The pH was adjusted to 7.5 with 10% sodium hydroxide. The mixture was stirred at 300rpm for 2 hours in a water bath at 65℃. The mixture was then centrifuged and the precipitate was collected. The precipitate was washed three times with deionized water and dried at 80℃ for 4 hours to obtain the composite powder.

[0045] Preparation of modified nano silica: Nano silica, fluorosilane, and tetrabutylphosphine ammonium bromide were added to a supercritical reactor, carbon dioxide was introduced, and the reaction was carried out at 8 MPa and 40 °C at a speed of 400 rpm for 2 h. The pressure was released to atmospheric pressure, the product was taken out, dried, pulverized and passed through a 200-mesh sieve to obtain modified nano silica.

[0046] The mass ratio of the nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide is 100:9:0.35.

[0047] Preparation of functional additives: Composite powder and modified nano-silica were mixed at a mass ratio of 3.5:2 to obtain a mixture. The mixture was then mixed with a 50% ethanol solution at a solid-liquid ratio of 1g:9mL and transferred to a planetary ball mill. The mixture was ball-milled at 500rpm for 2h to obtain a composite dispersion. The composite dispersion was then transferred to a subcritical reactor, and a mixed gas was introduced. The reactor was treated at 0.3MPa for 10min, followed by a reaction at 120℃ and 1.5MPa at 250rpm for 90min. After the reaction was completed, the reactor was cooled, depressurized, and the reaction solution was removed. The solution was then centrifuged to separate the precipitate, which was collected. The precipitate was washed with deionized water until neutral, dried, and pulverized to 120 mesh to obtain the functional additives.

[0048] The mixed gas is composed of perfluorooctylethylene and nitrogen in a volume ratio of 5:1.

[0049] Raw material preparation: 70 parts additives, 30 parts activated carbon, 10 parts polyacrylamide, 8 parts ammonium bicarbonate, 15 parts functional additives, and 120 parts deionized water.

[0050] Preparation of adsorbents for wastewater treatment: Step 1: Place the additives, activated carbon, polyacrylamide and ammonium bicarbonate in a high-speed mixer and stir at 1200 rpm for 15 minutes to obtain a premix. Add deionized water to the premix and knead to form wet granules with a particle size of 4 mm. Step 2: Dilute the functional additive with 50% of its volume of deionized water, spray it evenly onto the surface of the wet particles, let it stand and solidify at 60°C for 2 hours, then heat treat it at 110°C for 1 hour, and then dry it at 120°C to constant weight to obtain the adsorbent for wastewater treatment.

[0051] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not contain any additives.

[0052] Comparative Example 2: The difference between this comparative example and Example 1 is that this comparative example does not contain functional additives.

[0053] Comparative Example 3 differs from Example 1 in that ordinary nano-silica without supercritical modification is used in the preparation of the functional additives in this comparative example.

[0054] Performance testing: The adsorbents for wastewater treatment prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing, and the test data are recorded in the table below: Table 1 In the performance tests, the lead ion adsorption capacity was determined as follows: Following the similarity principle of GB / T 12496.8-2015, lead-containing simulated wastewater was prepared, and the saturated adsorption capacity of a unit mass of adsorbent for lead ions was determined under specified adsorption conditions. The methylene blue removal rate was determined as follows: Referring to the kinetic testing approach of GB / T 12496.10-1999, methylene blue solution was selected as the model organic pollutant, and the removal rate of methylene blue by the adsorbent within a fixed time was determined. The BET specific surface area was determined as follows: Referring to GB / T 19587-2017, the specific surface area and pore size distribution of the adsorbent were analyzed.

[0055] The data in the table obtained from the performance tests show that the adsorbents prepared in Examples 1-3 are superior to those in Comparative Examples 1-3 in key indicators such as lead ion adsorption capacity, methylene blue removal rate, and BET specific surface area. This fully demonstrates the crucial role of the synergistic design of additives and functional auxiliaries in this invention.

[0056] By comparing and analyzing the relevant data in the table, it can be seen that the adsorbent prepared by this invention not only has a good adsorption capacity for heavy metal ions, but also good removal performance for organic pollutants. This indicates that the wastewater treatment adsorbent provided by this invention has a broader market prospect and is more suitable for widespread application.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An adsorbent for wastewater treatment, characterized in that, It includes the following raw materials by weight: 50-70 parts additives, 20-30 parts activated carbon, 5-10 parts polyacrylamide, 3-8 parts ammonium bicarbonate, 5-15 parts functional additives, and 80-120 parts deionized water; The raw materials for the additive include oyster shell powder, citric acid solution, and reactants; The raw materials for the functional additives include composite powder and modified nano-silica.

2. The adsorbent for sewage treatment according to claim 1, characterized by The additive is prepared by the following method: oyster shell powder is transferred to a muffle furnace and calcined at 600℃ for 1.5-2.5h. After cooling, the calcined oyster shell powder is mixed with citric acid solution at a solid-liquid ratio of 1g:(9-11)mL and reacted at 60℃ for 1.5-2.5h. After filtration, the filter residue is washed with deionized water until neutral and dried to obtain acid-washed oyster shell powder. The acid-washed oyster shell powder is mixed with the reaction material at a mass ratio of 1:(0.08-0.15), and 2-3 times the mass of deionized water is added. The mixture is reacted at 70-80℃ for 2-4h. After filtration, the filter residue is washed with deionized water 3 times, dried, and ground through a 200-mesh sieve to obtain the additive. The concentration of the citric acid solution is 1.0mol / L.

3. The method for producing the adsorbent for sewage treatment according to claim 2, characterized by, The reactant is prepared by the following method: the additive powder and deionized water are mixed at a mass ratio of 1:(3.5-4.5) to obtain a first mixture. Under nitrogen protection, the first mixture is added dropwise to a ferrous sulfate solution at 40°C. After the addition is complete, the mixture is allowed to mature for 1 hour to obtain the reactant. The volume ratio of the first mixture to the ferrous sulfate solution is 1:(2.3-2.5), and the concentration of the ferrous sulfate solution is 0.4-0.6 mol / L.

4. The method for producing the adsorbent for sewage treatment according to claim 3, characterized by, The additive powder is prepared by the following method: itaconic acid and aminotrimethylenephosphonic acid are added to a reaction vessel at a molar ratio of 1:1 to obtain reactants. Deionized water, at 1-2 times the total mass of the reactants, is added, and the mixture is reacted at 80-90℃ for 4.5-5.5 hours. After the reaction is complete, the mixture is cooled to obtain a second mixture. The second mixture is poured into acetone at 4-6 times its volume, filtered, and the residue is washed twice with acetone and dried to obtain an intermediate product. Sodium alginate powder and the intermediate product are then added according to mass... Mix sodium alginate in a ratio of 1:(0.3-0.5), add 20 times the mass of deionized water, stir at 300-500 rpm for 30-60 min, add 1% of the mass of sodium alginate in potassium persulfate, and react in a water bath at 60-70℃ for 4 h to obtain a third mixture. Add the third mixture to anhydrous ethanol in a volume of 3-5 times, filter and collect the residue, wash the residue three times with anhydrous ethanol, dry it, grind it through a 200-mesh sieve to obtain the additive powder.

5. The method for producing the adsorbent for sewage treatment according to claim 1, characterized by, The functional additive is prepared by the following method: the composite powder and modified nano-silica are mixed at a mass ratio of (2.5-3.5):2 to obtain a mixture. The mixture is then mixed with a 50% volume concentration ethanol solution at a solid-liquid ratio of 1g:(7-9)mL and transferred to a planetary ball mill. The mixture is ball-milled at a speed of 300-500rpm for 2h to obtain a composite dispersion. The composite dispersion is then transferred to a subcritical reactor, and a mixed gas is introduced. The mixture is treated at 0.3MPa for 10min, followed by a reaction at 120℃ and 1.5MPa at a speed of 250rpm for 90min. After the reaction is completed, the mixture is cooled, depressurized, and the reaction solution is removed. The mixture is then centrifuged to separate the precipitate, which is collected. The precipitate is washed with deionized water until neutral, dried, and pulverized to 120 mesh to obtain the functional additive.

6. The method for preparing the adsorbent for wastewater treatment according to claim 5, characterized in that, The composite powder is prepared by the following method: Eucommia ulmoides leaves are dried, pulverized and passed through a 200-mesh sieve to obtain Eucommia ulmoides leaf powder. Eucommia ulmoides leaf powder is mixed with lignin at a mass ratio of (2.5-3.5):

1. Deionized water is added, and the solid-liquid ratio is controlled at 1g:(4-6)mL. The pH is adjusted to 7.0-7.5 with 10% sodium hydroxide. The mixture is stirred at 300rpm for 2h in a water bath at 55-65℃. The mixture is then centrifuged to separate the precipitate. The precipitate is washed three times with deionized water and dried at 80℃ for 4h to obtain the composite powder.

7. The method for preparing the adsorbent for wastewater treatment according to claim 5, characterized in that, The modified nano-silica was prepared by the following method: nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide were added to a supercritical reactor, carbon dioxide was introduced, and the reaction was carried out at 8 MPa and 40°C at a speed of 400 rpm for 2 hours. The pressure was then released to atmospheric pressure, the product was taken out, dried, pulverized and passed through a 200-mesh sieve to obtain modified nano-silica.

8. The method for preparing the adsorbent for wastewater treatment according to claim 7, characterized in that, The mass ratio of the nano-silica, fluorosilane, and tetrabutylphosphine ammonium bromide is 100:(7-9):(0.3-0.35).

9. The method for preparing the adsorbent for wastewater treatment according to claim 5, characterized in that, The mixed gas consists of perfluorooctylethylene and nitrogen in a volume ratio of (4-5):

1.

10. The method for preparing the adsorbent for wastewater treatment according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Place the additives, activated carbon, polyacrylamide and ammonium bicarbonate in a high-speed mixer and stir at 800-1200 rpm for 10-15 minutes to obtain a premix. Add deionized water to the premix and knead to form wet granules with a particle size of 2-4 mm. Step 2: Dilute the functional additive with 50% of its volume of deionized water, spray it evenly onto the surface of the wet particles, let it stand and solidify at 60°C for 2 hours, then heat treat it at 110°C for 1 hour, and then dry it at 120°C to constant weight to obtain the adsorbent for wastewater treatment.

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