High-performance water treatment agent, preparation method thereof and application of high-performance water treatment agent in treatment of phosphorus-containing wastewater

Abstract

The invention discloses a high-performance water treatment agent and a preparation method and application thereof.The high-performance water treatment agent comprises a modified zeolite imidazate framework structure material and a modified biochar material, and the modified zeolite imidazate framework structure material is a zeolite imidazate framework structure material modified through acid etching; the modified biochar material is prepared by modifying biological activated carbon prepared by taking sludge as a raw material with reticular lanthanum carbonate. The high-performance water treatment agent provided by the invention not only is simple to prepare, but also can effectively remove organic phosphorus and inorganic phosphorus in wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a high-performance water treatment agent and a preparation method thereof, as well as application in treating phosphorus-containing wastewater. Background Art

[0002] As we all know, phosphorus is an essential element for life in nature and affects the primary productivity of aquatic ecosystems. Phosphorus is also a controlling factor for eutrophication of most water bodies, so it is particularly important to control the phosphorus concentration in sewage. Phosphorus usually exists in water bodies in the form of low-concentration phosphates. Currently, there are strict restrictions on the phosphorus concentration in discharged sewage around the world. Phosphorus removal treatment of industrial wastewater can not only reduce the amount of phosphorus discharged.

[0003] At present, the main treatment methods for phosphorus-containing wastewater include biological method, chemical precipitation method, adsorption method, crystallization method, ion exchange method and the combined use of the above methods. Phosphorus removal technology is to remove phosphorus from wastewater by converting phosphorus in wastewater into insoluble phosphate precipitates, or by using crystallization and adsorption, or by cellular synthesis to absorb phosphorus into sludge cells, and then separating solid and liquid by precipitation, filtration and other means.

[0004] Patent No. 201310266649.3 provides an energy-saving adsorption treatment material for phosphorus-containing industrial wastewater, characterized in that it includes the following substances in weight: 8-16 parts of graphite, 2-4 parts of ethanol, 3-8 parts of iron oxide, 10-35 parts of wood fiber (100-500 mesh), 21-34 parts of diatomaceous earth (200-300 mesh), 20-36 parts of open-pore expanded perlite (10-150 mesh), 10-34 parts of hollow glass microspheres (120-200 mesh), 10-16 parts of cement ash aqueous solution, and 9-15 parts of iron oxide. Although the above materials have certain adsorption properties, they have poor removal effects on organic phosphorus in wastewater, and the cost of the above adsorption materials is relatively high. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a high-performance water treatment agent and a preparation method thereof and application in phosphorus-containing wastewater are provided. The high-performance water treatment agent provided by the present invention is not only simple to prepare, but also can effectively remove organic phosphorus and inorganic phosphorus in wastewater.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: A high-performance water treatment agent comprises a modified zeolite imidazolate framework structure material and a modified biochar material. The modified zeolite imidazolate framework structure material is a zeolite imidazolate framework structure material modified by acid etching, and the modified biochar material is biological activated carbon prepared by using sludge as raw material and modified by using reticulated lanthanum carbonate.

[0007] In order to better solve the above technical problems, the present invention provides the following technical solutions: A method for preparing a high-performance water treatment agent comprises the following steps: (1) adding the zinc salt solution dropwise to the organic ligand solution, mixing and stirring to react, centrifuging the reaction solution after the reaction is completed, and drying the centrifugal precipitation to obtain a zeolite imidazole ester framework structure material; (2) dispersing the above-mentioned zeolite imidazolate framework structure material in deionized water, then adding sulfuric acid solution, stirring at room temperature, centrifuging after completion, washing the centrifugal precipitate and drying to obtain a modified zeolite imidazolate framework structure material; (3) dissolving polyethylene glycol, lanthanum salt, and dehydrated sludge in deionized water to obtain a mixed solution, freezing the mixed solution, then performing vacuum freeze drying, and finally calcining to obtain a modified biochar material; (4) The modified zeolite imidazolate skeleton structure material and the modified biochar material are mixed and ground to obtain a high-performance water treatment agent.

[0008] Preferably, in step (1), the zinc salt solution is a zinc nitrate hexahydrate solution with a concentration of 0.01-0.015 g / ml; and / or the organic ligand solution is a 2-methylimidazole solution with a concentration of 0.03-0.04 g / ml; and / or the stirring speed of the mixed stirring reaction is 2000-3000 rpm, the stirring temperature is room temperature, and the stirring time is 3-5 h.

[0009] Preferably, in step (2), the pH of the sulfuric acid solution is 2-3; and / or the dosage ratio of the zeolite imidazolate framework material and the sulfuric acid solution is 5 mg: (30-50) ml; and / or the stirring speed of the stirring treatment is 2000-3000 rpm, and the stirring time is 6-10 h.

[0010] Preferably, in step (3), the lanthanum salt is lanthanum nitrate hexahydrate, the polyethylene glycol is polyethylene glycol 2000, and the mass ratio of the polyethylene glycol, the lanthanum salt and the sewage sludge is 1:1:(1-2).

[0011] Preferably, in step (3), the freezing condition is -15 to -20°C for 8 to 10 hours; and / or the freeze-drying temperature is -60 to -70°C, the vacuum degree is 0.1 to 0.2 Pa, and the time is 24 to 30 hours.

[0012] Preferably, in step (3), the calcination time is 500-600° C. and the time is 1-3 h.

[0013] Preferably, in step (4), the mass ratio of the modified zeolite imidazolate framework structure material to the modified biochar material is 1:(1-5). In order to better solve the above technical problems, the present invention also provides the following technical solutions: Application of a high-performance water treatment agent in the treatment of phosphorus-containing wastewater comprises the following steps: After the phosphorus-containing wastewater is initially precipitated, a high-performance water treatment agent is added to the supernatant, and the mixture is stirred and adsorbed at room temperature, and then filtered to obtain phosphorus-removed wastewater.

[0014] Preferably, the addition amount of the high-performance water treatment agent is 0.5-2 g / L; the stirring speed of the stirring adsorption treatment is 100-200 rpm, and the time is 10-15 h.

[0015] Due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention uses an acid-etched zeolite imidazolate skeleton structure material and a mesh lanthanum carbonate modified biochar material as a water treatment agent, which can not only effectively adsorb phosphates in wastewater, but also effectively adsorb organic phosphorus in wastewater, thereby improving the wastewater treatment effect. The preparation method of the water treatment agent is simple and has low equipment requirements.

[0016] 2. The present invention performs acid etching on the zeolite imidazolate framework structure material, and by effectively optimizing the treatment conditions, the obtained modified zeolite imidazolate framework structure material has more zinc-rich sites and a higher surface positive zeta potential, which can better specifically bind to inorganic phosphorus and organic phosphorus, thereby improving the wastewater treatment effect.

[0017] 3. The present invention uses dewatered sludge as a carbon source, polyethylene glycol as a porogen, and lanthanum nitrate hexahydrate as a lanthanum source. Through freezing and vacuum freeze-drying technology combined with calcination treatment, lanthanum carbonate is distributed on the porous biochar skeleton to achieve modification. This structure not only has many active sites, but also lanthanum carbonate has a strong binding force for phosphorus, thereby improving the phosphorus removal effect. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] In the following examples and comparative examples, unless otherwise specified, the raw materials are all commercially available and the conditions are all conventional conditions in the art. Example 1

[0021] A high-performance water 1 is dissolved in 100 ml of deionized water to obtain a hexahydrate zinc nitrate solution, 3.25 g of 2-methylimidazole is dissolved in 100 ml of deionized water to obtain a 2-methylimidazole solution, the hexahydrate zinc nitrate solution and the 2-methylimidazole solution are mixed in a volume ratio of 1:1, stirred at a speed of 2000 rpm for 3 hours at room temperature, and after the reaction is completed, the reaction solution is centrifuged at a speed of 8000 rpm for 5 minutes, and the centrifugal precipitation is dried to obtain a zeolite imidazole ester framework structure material; (2) Dispersing 5 mg of zeolite imidazolate framework material into 5 ml of deionized water, adding 30 ml of sulfuric acid solution with a pH of 2, stirring at 2000 rpm for 8 h at room temperature, and then centrifuging at 5000 rpm. After centrifugal precipitation and drying, a modified zeolite imidazolate framework material was obtained; (3) 2 g of polyethylene glycol, 2 g of lanthanum nitrate hexahydrate, 2 g of dehydrated sludge and 100 ml of deionized water were mixed, and the resulting mixed solution was frozen at -20 °C for 8 h, and then vacuum freeze-dried at a temperature of -65 °C and a vacuum degree of 0.1 Pa for 24 h, and finally taken out and calcined at 5500 °C for 1 h in an inert atmosphere to obtain a modified biochar material; (4) The modified zeolite imidazolate framework structure material and the modified biochar material are mixed and ground in a mass ratio of 1:1 to obtain a high-performance water treatment agent. Example 2

[0022] A method for preparing a high-performance water treatment agent comprises the following steps: (1) Dissolving 1.42 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate hexahydrate solution, dissolving 3.25 g of 2-methylimidazole in 100 ml of deionized water to obtain a 2-methylimidazole solution, mixing the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in a volume ratio of 1:1, stirring at 2500 rpm for 4 hours at room temperature, and after the reaction is completed, centrifuging the reaction solution at 8000 rpm for 6 minutes, centrifuging and drying the precipitate to obtain a zeolite imidazole framework material; (2) Dispersing 5 mg of zeolite imidazolate framework material into 5 ml of deionized water, adding 40 ml of sulfuric acid solution with a pH of 2, stirring at 2500 rpm for 7 h at room temperature, and then centrifuging at 5000 rpm. After centrifugal precipitation and drying, a modified zeolite imidazolate framework material was obtained; (3) 2 g of polyethylene glycol, 2 g of lanthanum nitrate hexahydrate, 3 g of dehydrated sludge and 100 ml of deionized water were mixed, and the resulting mixed solution was frozen at -20 °C for 8 h, and then vacuum freeze-dried at a temperature of -65 °C and a vacuum degree of 0.1 Pa for 24 h, and finally taken out and calcined at 550 °C for 2 h in an inert atmosphere to obtain a modified biochar material; (4) The modified zeolite imidazolate framework structure material and the modified biochar material are mixed and ground in a mass ratio of 1:3 to obtain a high-performance water treatment agent. Example 3

[0023] A method for preparing a high-performance water treatment agent comprises the following steps: (1) Dissolve 1.45 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate hexahydrate solution, dissolve 3.25 g of 2-methylimidazole in 100 ml of deionized water to obtain a 2-methylimidazole solution, mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in a volume ratio of 1:1, stir at room temperature at a speed of 2500 rpm for 4 hours, centrifuge the reaction solution at a speed of 8000 rpm for 5 minutes after the reaction is completed, and centrifuge the precipitate to dry to obtain a zeolite imidazole framework structure material; (2) Dispersing 5 mg of zeolite imidazolate framework material into 5 ml of deionized water, adding 50 ml of sulfuric acid solution with a pH of 2, stirring at 2500 rpm for 8 h at room temperature, and then centrifuging at 5000 rpm. After centrifugal precipitation and drying, the modified zeolite imidazolate framework material was obtained; (3) 2 g of polyethylene glycol, 2 g of lanthanum nitrate hexahydrate, 3 g of dehydrated sludge and 100 ml of deionized water were mixed, and the resulting mixed solution was frozen at -20 °C for 8 h, and then vacuum freeze-dried at a temperature of -65 °C and a vacuum degree of 0.1 Pa for 24 h, and finally taken out and calcined at 550 °C for 2 h in an inert atmosphere to obtain a modified biochar material; (4) The modified zeolite imidazolate framework structure material and the modified biochar material are mixed and ground in a mass ratio of 1:4 to obtain a high-performance water treatment agent. Example 4

[0024] A method for preparing a high-performance water treatment agent comprises the following steps: (1) Dissolve 1.45 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate hexahydrate solution, dissolve 3.3 g of 2-methylimidazole in 100 ml of deionized water to obtain a 2-methylimidazole solution, mix the zinc nitrate hexahydrate solution and the 2-methylimidazole solution in a volume ratio of 1:1, stir at room temperature at a speed of 3000 rpm for 4 hours, and after the reaction is completed, centrifuge the reaction solution at a speed of 8000 rpm for 10 minutes, centrifuge and dry the precipitate to obtain a zeolite imidazole framework structure material; (2) Dispersing 5 mg of zeolite imidazolate framework material into 5 ml of deionized water, adding 50 ml of sulfuric acid solution with a pH of 2, stirring at 3000 rpm for 8 h at room temperature, and then centrifuging at 5000 rpm. After centrifugal precipitation and drying, a modified zeolite imidazolate framework material was obtained; (3) 2 g of polyethylene glycol 2000, 2 g of lanthanum nitrate hexahydrate, 3.5 g of dehydrated sludge and 100 ml of deionized water were mixed, and the resulting mixed solution was frozen at -20 °C for 8 h, and then vacuum freeze-dried at a temperature of -65 °C and a vacuum degree of 0.1 Pa for 24 h, and finally taken out and calcined at 550 °C for 2 h in an inert atmosphere to obtain a modified biochar material; (4) The modified zeolite imidazolate framework structure material and the modified biochar material are mixed and ground in a mass ratio of 1:3 to obtain a high-performance water treatment agent.

[0025] In order to further verify the effect of the present invention, the present invention is further described in detail below with reference to Example 1 and in combination with a plurality of comparative examples.

[0026] Comparative Example 1 Compared with Example 1, the difference is that the high-performance water treatment agent only includes the modified zeolite imidazolate framework structure material, and does not include the modified biochar material. Other conditions are the same as those in Example 1.

[0027] Comparative Example 2 Compared with Example 1, the difference is that the high-performance water treatment agent only includes modified biochar material, and does not include modified zeolite imidazolate framework structure material, and other conditions are the same as Example 1.

[0028] Comparative Example 3 Compared with Example 1, the difference is that step (2) is not included, and other conditions are the same as those in Example 1.

[0029] Comparative Example 4 Compared with Example 1, the difference is that lanthanum nitrate hexahydrate is not added in step (3), and other conditions are the same as those in Example 1.

[0030] Comparative Example 5 Compared with Example 1, the difference is that polyethylene glycol 2000 is not added in step (3), and the other conditions are the same as those in Example 1.

[0031] Comparative Example 6 Compared with Example 1, the difference is that in step (2), the stirring time is 15 hours, and the other conditions are the same as in Example 1.

[0032] Comparative Example 7 Compared with Example 1, the difference is that in step (2), the stirring time is 4 hours, and the other conditions are the same as in Example 1. Application Examples

[0033] After the phosphorus-containing wastewater (glyphosate concentration of 50 mg / L, phosphate concentration of 50 mg / L) was initially precipitated, the water treatment agents prepared in the above embodiments and comparative examples (added amount of 0.5 g / L) were added to the supernatant, respectively, and adsorbed at 120 rpm for 12 hours, filtered, and the concentrations of glyphosate and phosphate in the filtrate were detected, and then the removal rates of glyphosate and phosphate were calculated. The results are shown in Table 1.

[0034] Table 1

[0036] It can be seen from the test results in Table 1 that, compared with the comparative example, the present invention adopts a compound of modified zeolite imidazolate framework structure material and modified biochar material as a high-performance water treatment agent, which can simultaneously remove organic phosphorus and inorganic phosphorus in wastewater with a removal efficiency of more than 95%.

[0037] In Comparative Examples 1 and 2, only modified zeolite imidazolate skeleton structure materials or modified biochar materials are added, and the removal effects of organic phosphorus and inorganic phosphorus are reduced. In Comparative Example 3, the prepared zeolite imidazolate skeleton structure material is not modified, and the removal effects of organic phosphorus and inorganic phosphorus are also reduced, mainly because after acid etching, the active sites of the material are greatly increased, which can produce stronger electrostatic attraction and more hydroxyls to form hydrogen bonds with glyphosate and phosphate in the wastewater. In Comparative Example 4, the biochar material is not modified with lanthanum, and in Comparative Example 5, polyethylene glycol 2000 is not added for modification, and the treatment effect of phosphorus-containing wastewater is reduced, because there is a strong binding ability between La ions and phosphates, which can effectively improve the phosphorus removal effect, and polyethylene glycol as a porogen can effectively improve the porosity of water treatment, thereby improving its adsorption.

[0038] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A high performance water treatment agent, Features: It includes a modified zeolite imidazolate skeleton structure material and a modified biochar material. The modified zeolite imidazolate skeleton structure material is a zeolite imidazolate skeleton structure material modified by acid etching. The modified biochar material is biological activated carbon prepared by using sludge as raw material and modified by using lanthanum carbonate reticulate.

2. A method for preparing a high-performance water treatment agent according to claim 1, It is characterized in that The following steps are involved: (1) adding the zinc salt solution dropwise to the organic ligand solution, mixing and stirring to react, centrifuging the reaction solution after the reaction is completed, and drying the centrifugal precipitation to obtain a zeolite imidazole ester framework structure material; (2) dispersing the above-mentioned zeolite imidazolate framework structure material in deionized water, then adding sulfuric acid solution, stirring at room temperature, centrifuging after completion, washing the centrifugal precipitate and drying to obtain a modified zeolite imidazolate framework structure material; (3) dissolving polyethylene glycol, lanthanum salt, and dehydrated sludge in deionized water to obtain a mixed solution, freezing the mixed solution, then performing vacuum freeze drying, and finally calcining to obtain a modified biochar material; (4) The modified zeolite imidazolate framework material and the modified biochar material are mixed and ground to obtain a high-performance water treatment agent.

3. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (1), the zinc salt solution is a zinc nitrate hexahydrate solution with a concentration of 0.01-0.015 g / ml; and / or the organic ligand solution is a 2-methylimidazole solution with a concentration of 0.03-0.04 g / ml; and / or the stirring speed of the mixed stirring reaction is 2000-3000 rpm, the stirring temperature is room temperature, and the stirring time is 3-5 h.

4. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (2), the pH of the sulfuric acid solution is 2-3; and / or the dosage ratio of the zeolite imidazolate framework material to the sulfuric acid solution is 5 mg: (30-50) ml; and / or the stirring speed of the stirring treatment is 2000-3000 rpm, and the stirring time is 6-10 h.

5. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (3), the lanthanum salt is lanthanum nitrate hexahydrate, the polyethylene glycol is polyethylene glycol 2000, and the mass ratio of the polyethylene glycol, the lanthanum salt and the sewage sludge is 1:1:(1-2).

6. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (3), the freezing condition is -15 to -20°C for 8 to 10 hours; and / or the freeze-drying temperature is -60 to -70°C, the vacuum degree is 0.1 to 0.2 Pa, and the time is 24 to 30 hours.

7. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (3), the calcination time is 500-600°C for 1-3 hours.

8. A method for preparing a high-performance water treatment agent according to claim 2, Features: In step (4), the mass ratio of the modified zeolite imidazolate framework structure material to the modified biochar material is 1:(1-5).

9. Use of a high-performance water treatment agent according to claim 1, It is characterized in that The following steps are involved: After the phosphorus-containing wastewater is initially precipitated, a high-performance water treatment agent is added to the supernatant, and the mixture is stirred and adsorbed at room temperature, and then filtered to obtain phosphorus-removed wastewater.

10. Use of a high-performance water treatment agent according to claim 9, It is characterized in that The addition amount of the high-performance water treatment agent is 0.5-2 g / L; the stirring speed of the stirring adsorption treatment is 100-200 rpm, and the time is 10-15 hours.

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