Composite treatment agent for sewage treatment and preparation method thereof

Abstract

The present invention discloses a composite treatment agent for sewage treatment and a preparation method thereof. The composite treatment agent comprises the following raw materials, by weight: 50-60 parts of modified diatomaceous earth, 10-20 parts of zeolite powder, 10-20 parts of polyaluminium chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide, and 4-8 parts of sodium lauryl sulfate. The composite treatment agent is prepared by mixing modified diatomaceous earth, zeolite powder, polyaluminium chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate in a specific ratio, so that the obtained composite treatment agent has good adsorption properties, can quickly and efficiently adsorb heavy metal ions in sewage, and can also complex organic pollutants in sewage, thus having good application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and particularly relates to a composite treatment agent for sewage treatment and a preparation method thereof. Background Art

[0002] Water is a precious natural resource and essential for human survival. Currently, organic wastewater, dye wastewater, and heavy metal wastewater account for a significant proportion of industrial wastewater, necessitating the use of efficient and reliable wastewater treatment methods to address these issues.

[0003] Industrial wastewater is a significant component of modern wastewater. With the development of industry, the discharge and recycling of more and more industrial wastewater requires our attention. Unlike domestic wastewater, industrial wastewater contains many heavy metals, causing more severe environmental pollution and posing a threat to human health. Therefore, the treatment of industrial wastewater is even more critical than that of domestic wastewater.

[0004] At present, the common sewage treatment methods mainly include flocculation sedimentation, chemical oxidation, biodegradation and adsorption. Among them, the adsorption method has been proven to be able to quickly reduce the content of heavy metals and organic pollutants in sewage. The adsorption method is widely used in the treatment of dye sewage, petrochemical sewage, oil and gas field sewage, heavy metal sewage, and dye sewage. The adsorption method generally uses porous adsorbents to remove organic pollutants, heavy metal ions, dye pollutants, etc. in sewage; because the porous adsorbents used are solid substances, in sewage treatment, they can adsorb and separate pollutants in sewage at a lower sewage treatment energy consumption, and will not introduce new pollutants into the sewage; and after sewage treatment, it is easy to perform solid-liquid separation, will not cause secondary pollution to the environment, and has a good effect on the deep treatment of wastewater. Therefore, the adsorption method has always been one of the mainstream methods for industrial wastewater treatment.

[0005] Chinese patent application CN114247419A discloses an adsorbent material, its preparation method, and its application. The material is primarily obtained by modifying a solid catalyst with alkali and lanthanum ions; the main components of the solid catalyst include SiO2, Al2O3, and Fe3O4. The raw material for the adsorbent material is a waste catalyst from the Fischer-Tropsch synthesis process. After modification, it can be reused as an adsorbent in wastewater treatment, with low adsorption costs and the ability to effectively adsorb fluoride ions from coal chemical wastewater. However, this adsorbent only has a good adsorption effect on fluoride ions in wastewater, while chemical wastewater contains a complex composition that includes a variety of harmful chemicals, such as organic matter, heavy metals, organic solvents, and other pollutants. These multiple pollutants may mutually affect the adsorption efficiency of the adsorbent. Chinese patent application CN107866208A discloses a composite sewage treatment agent based on modified diatomaceous earth, its preparation method, and its application. The composite sewage treatment agent is primarily prepared by mixing diatomaceous earth with a pale yellow viscous sol. The preparation method of the composite sewage treatment agent includes the following steps: (1) activation of diatomaceous earth; (2) preparation of a light yellow viscous sol; (3) diluting the light yellow viscous sol and adding the activated diatomaceous earth, continuously stirring and filtering, and then drying the sample to prepare the composite sewage treatment agent. The composite sewage treatment agent is added to sewage, and under the condition that the pH of the sewage is 6, adsorption and stirring are carried out for 30 minutes, and the sewage purification process is completed after standing for 1 hour. The composite sewage treatment agent of the invention is based on modified diatomaceous earth and is compounded with a light yellow viscous sol cross-linked with γ-polyglutamic acid and chitosan. The preparation method of the composite sewage treatment agent is simple, practical and convenient, with short treatment time and low cost, and good sewage treatment effect and stable indicators. However, the description of the invention does not indicate the treatment effect of the composite sewage treatment agent on heavy metal ions and organic pollutants in sewage.

[0006] Therefore, it is of great significance to develop a composite treatment agent for sewage treatment with good treatment effect in this field. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a composite treatment agent for sewage treatment and a preparation method thereof. The composite treatment agent has good adsorption properties for heavy metals, can quickly and efficiently adsorb heavy metal ions in sewage, and can also complex organic pollutants in sewage, and has good application prospects.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0010] 50-60 parts of modified diatomaceous earth, 10-20 parts of zeolite powder, 10-20 parts of polyaluminium chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide, and 4-8 parts of sodium lauryl sulfate.

[0011] Preferably, a composite treatment agent for sewage comprises the following raw materials in parts by weight:

[0012] 55-60 parts of modified diatomaceous earth, 15-20 parts of zeolite powder, 10-15 parts of polyaluminium chloride, 10-15 parts of activated carbon, 7-10 parts of shell powder, 5-8 parts of polyacrylamide, and 4-6 parts of sodium lauryl sulfate.

[0013] In the present invention, zeolite powder has good adsorption capacity and has many cavities and pores; zeolite powder can effectively adsorb suspended matter in water that has not been flocculated and precipitated; and zeolite powder can also be adsorbed on flocs to increase the precipitation rate of the flocs; zeolite powder and polyaluminum chloride work together to effectively improve the flocculation and precipitation of organic pollutants in sewage.

[0014] Preferably, the particle size of the zeolite powder is 300-400 μm; the particle size of the activated carbon is 100-200 μm; and the particle size of the shell powder is 0.5-2 mm.

[0015] Preferably, the preparation method of the modified diatomaceous earth comprises the following steps:

[0016] S1, adding diatomaceous earth to an aqueous nitric acid solution, filtering, washing, and drying after immersion treatment to obtain acidified diatomaceous earth; then adding the acidified diatomaceous earth to a sodium hydroxide solution, stirring and heating, filtering, washing, drying, and calcining after the treatment to obtain pretreated diatomaceous earth;

[0017] S2, adding the pretreated diatomaceous earth and Tween 20 in step S1 to a Ca(NO3)2 solution, followed by a KH2PO4 solution, and then dropping nitric acid into the solution to adjust the pH to 2-3. After ultrasonic dispersion, a hydrothermal reaction is performed. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain a composite diatomaceous earth;

[0018] S3, adding the composite diatomaceous earth in step S2 to an ethanol aqueous solution, then adding γ-aminopropyltriethoxysilane, stirring to react, and filtering, washing, and drying after the reaction is completed to obtain an amino-modified composite diatomaceous earth;

[0019] S4. Add trans-3-(3-pyridyl)allylic acid to N,N-dimethylformamide, then add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stir for 30 minutes. Then add the amino-composite diatomite and N-hydroxysuccinimide in step S3 to carry out heating reaction. After the reaction is completed, filter, wash, and dry to obtain a solid product. Subsequently, add the solid product to dimethyl sulfoxide, and then add 4-acrylamidebenzo-18-crown ether and ammonium persulfate to carry out constant temperature reaction. After the reaction is completed, filter, wash, and dry to obtain the modified diatomite.

[0020] Diatomaceous earth, as a biogenic siliceous rock, has a certain adsorption capacity due to its unique physical and chemical properties such as large specific surface area, many micropores and surfactant groups, and negative surface charge. It is widely used to adsorb heavy metals and pigments in water bodies. However, since natural diatomaceous earth contains impurities and has defects in its physical and chemical structure, its adsorption capacity is limited. Therefore, the present invention modifies it. On the one hand, it can be modified to improve the pore structure and fully enhance the adsorption capacity. On the other hand, functional functional groups are introduced to enhance its ability to complex organic pollutants, significantly improving the comprehensive adsorption capacity of diatomaceous earth.

[0021] Preferably, the mass concentration of the nitric acid aqueous solution in step S1 is 5-8%, the temperature of the immersion treatment is 60-70°C, and the time is 1-2h; the mass concentration of the sodium hydroxide solution is 5-8%, the temperature of the stirring and heating treatment is 60-70°C, and the time is 1-2h, and the temperature of the roasting is 300-350°C, and the time is 1-2h.

[0022] In the present invention, the diatomite is firstly acidified. The acid treatment can effectively remove soluble impurities such as organic matter on the surface and in the pores of the diatomite, thereby improving the surface and pore structure of the diatomite, increasing the specific surface area, and increasing the number of effective adsorption points, which is conducive to the occurrence of adsorption. Subsequently, alkali washing is performed. The strong alkali reduces the silanol groups on the surface of the diatomite, thereby improving the purity of the diatomite and increasing the specific surface area and pore volume, thereby improving the structure of the diatomite and enhancing the adsorption capacity. The diatomite is then calcined at high temperature to fully expand the pores of the diatomite and increase the stability of the pore structure of the diatomite.

[0023] Preferably, the concentration of the Ca(NO3)2 solution in step S2 is 0.5-0.8 mol / L, the concentration of the KH2PO4 solution is 0.5-0.8 mol / L, the mass volume ratio of the pretreated diatomaceous earth, Tween 20, Ca(NO3)2 solution, and KH2PO4 solution is 20 g:1-2 g:500-800 mL:300-500 mL, the temperature of the hydrothermal reaction is 140-150 ° C, and the time is 3-5 h.

[0024] In the present invention, hydroxyapatite is in situ generated on diatomite by a hydrothermal method. The hydroxyapatite is rich in hydroxyl (-OH) and calcium-phosphorus ion groups, which can exchange calcium-phosphorus ions with heavy metal ions to form complexes, thereby improving the adsorption capacity of the modified diatomite for heavy metal ions. At the same time, the addition of Tween-20 during the preparation process can effectively improve the dispersibility of the modified diatomite.

[0025] Preferably, the mass fraction of ethanol in the ethanol aqueous solution in step S3 is 60-70%, the mass ratio of the composite diatomaceous earth and γ-aminopropyltriethoxysilane is 50-60:8-12, the stirring reaction temperature is 60-70° C., and the time is 2-3 h.

[0026] In the present invention, the composite diatomaceous earth is reacted with γ-aminopropyltriethoxysilane to introduce amino groups on the surface of the diatomaceous earth, which is beneficial to the subsequent reaction.

[0027] Preferably, in step S4, the mass ratio of the aminated composite diatomaceous earth, trans-3-(3-pyridyl)allylic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide is 50:5-8:20-30:20-30, the temperature of the heating reaction is 90-100°C, and the time is 3-5h; the mass ratio of the solid product, 4-acrylamidebenzo-18-crown ether, and ammonium persulfate is 50:6-9:0.1-0.2, the temperature of the constant temperature reaction is 100-110°C, and the time is 1-2h.

[0028] In the present invention, the amino-modified composite diatomite is reacted with trans-3-(3-pyridyl)allylic acid to make the composite diatomite bonded with trans-3-(3-pyridyl)allylic acid in the form of a covalent bond, thereby introducing a pyridine group. The pyridine group contains a nitrogen atom. The lone pair of electrons on the nitrogen atom can coordinate with the empty orbital of the metal ion to form a coordination bond with the metal ion, thereby improving the adsorption of the modified diatomite to heavy metal ions. Subsequently, 4-acrylamide benzo-18-crown ether is reacted with the diatomite to introduce a crown ether and an amide group into the diatomite. The amide group The oxygen atoms and nitrogen atoms in the crown ether both have lone pairs of electrons, which can act as ligands to form coordination bonds with heavy metal ions. In addition, the lone pairs of electrons on the oxygen atoms in the crown ether form coordination bonds with the metal ions. The two act synergistically with the pyridine group to significantly improve the adsorption of heavy metal ions by diatomaceous earth. At the same time, the benzene rings in the crown ether can interact with aromatic organic matter in sewage through π-π stacking, and the alkyl chain segments in the crown ether can produce hydrophobic interactions with hydrophobic organic molecules, thereby significantly improving the removal of organic pollutants in sewage by the modified diatomaceous earth and improving the comprehensive performance of the modified diatomaceous earth in treating sewage.

[0029] The present invention also protects a method for preparing the composite treatment agent for sewage as described above, comprising the following steps:

[0030] The raw materials are weighed according to the formula, and the modified diatomaceous earth, zeolite powder, polyaluminium chloride, activated carbon, shell powder, polyacrylamide, sodium lauryl sulfate and ethanol solution are mixed and ground, and dried at 80-90° C. to obtain the composite treatment agent.

[0031] The present invention also protects the use of the composite treatment agent for sewage as described above in treating chemical sewage.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The composite treatment agent for sewage treatment provided by the present invention is prepared by compounding and mixing modified diatomaceous earth, zeolite powder, polyaluminium chloride, activated carbon, shell powder, polyacrylamide and sodium lauryl sulfate in a specific ratio. The modified diatomaceous earth, zeolite powder and activated carbon have good ability to adsorb heavy metals and organic pollutants, polyaluminium chloride has a sedimentation effect, sodium lauryl sulfate has good dispersibility, polyacrylamide is used as a flocculant to remove suspended matter and colloids in water, and shell powder can effectively adsorb heavy metal ions in water due to its large surface area and high porosity. The obtained composite treatment agent has good adsorption, can quickly and efficiently adsorb heavy metal ions in sewage, and can also complex organic pollutants in sewage, and has good application prospects.

[0034] (2) The composite treatment agent for sewage treatment provided by the present invention is added with modified diatomaceous earth, and the diatomaceous earth is acidified, alkali-washed and calcined, thereby improving the purity of the diatomaceous earth, increasing the specific surface area and pore volume, improving the structure of the diatomaceous earth, improving the adsorption capacity, fully expanding the diatomaceous earth pores, and increasing the stability of the diatomaceous earth pore structure; then, a hydrothermal method is used to in situ generate hydroxyapatite on the diatomaceous earth, and the hydroxyapatite is rich in hydroxyl (-OH) and calcium-phosphorus ion groups, which can exchange calcium-phosphorus ions with heavy metal ions to form complexes, thereby improving the adsorption capacity of the modified diatomaceous earth for heavy metal ions. At the same time, Tween-20 is added during the preparation process to effectively improve the dispersibility of the modified diatomaceous earth; then, a chemical reaction is used to graft trans-3-(3-pyridyl)allylic acid and 4-acrylamidebenzo-18-crown ether to the diatomaceous earth in the form of covalent bonds. On the surface, pyridine groups, crown ether groups and amide groups are introduced. The pyridine group contains a nitrogen atom. The lone pair of electrons on the nitrogen atom can coordinate with the empty orbital of the metal ion and form a coordination bond with the metal ion, thereby improving the adsorption of the modified diatomaceous earth to heavy metal ions. The oxygen atom and the nitrogen atom in the amide group both have lone pairs of electrons, which can serve as ligands to form coordination bonds with heavy metal ions, and the lone pair of electrons on the oxygen atom in the crown ether forms a coordination bond with the metal ion. The two act synergistically with the pyridine group, significantly improving the adsorption of diatomaceous earth to heavy metal ions; at the same time, the benzene ring in the crown ether can interact with aromatic organic matter in sewage through π-π stacking, and the alkyl chain segment in the crown ether can produce hydrophobic interactions with hydrophobic organic molecules, thereby significantly improving the removal of organic pollutants in sewage by the modified diatomaceous earth, and improving the comprehensive performance of the modified diatomaceous earth in treating sewage.

[0035] (3) The composite treatment agent for sewage treatment provided by the present invention is prepared by a specific method to obtain modified diatomaceous earth, and trans-3-(3-pyridyl)allylic acid and 4-acrylamidebenzo-18-crown ether are grafted onto the diatomaceous earth in the form of covalent bonds, thereby avoiding secondary pollution caused by the shedding of small organic molecules during sewage treatment, improving the treatment efficiency of the composite treatment agent, and expanding the application field. DETAILED DESCRIPTION

[0036] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In the present invention, the zeolite powder was purchased from Zhongzheng Perlite Factory in Pingqiao District, Xinyang City, with a particle size of 300-400 μm; the activated carbon was purchased from Chengde Tianyuan Activated Carbon Co., Ltd., with a particle size of 100-200 μm; the shell powder was purchased from Lingshou County Jiayuan Mineral Products Processing Plant, with a particle size of 0.5-2 mm; the polyaluminum chloride was purchased from Gongyi Shuizhiyuan Water Purification Materials Co., Ltd., with an alumina content of 28%; the polyacrylamide was purchased from Wuxi Lanbo Chemicals Co., Ltd., with a molecular weight of 8 million.

[0038] Example 1

[0039] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0040] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminium chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide and 6 parts of sodium lauryl sulfate.

[0041] The preparation method of the modified diatomaceous earth comprises the following steps:

[0042] S1, 100g of diatomaceous earth was added to 1L of 7% nitric acid aqueous solution, immersed at 65°C for 1.5h, then filtered, washed, and dried to obtain acidified diatomaceous earth; then 100g of acidified diatomaceous earth was added to 7% sodium hydroxide solution, stirred and heated at 65°C for 1.5h, filtered, washed, dried, and calcined at 330°C for 1.5h to obtain pretreated diatomaceous earth;

[0043] S2, adding 20g of pretreated diatomaceous earth and 1.5g of Tween 20 in step S1 to 700mL of 0.6mol / L Ca(NO3)2 solution, followed by adding 400mL of 0.7mol / L KH2PO4 solution, and then adding 7% nitric acid dropwise to the solution, adjusting the pH to 2.5, ultrasonically dispersing for 30min, and then hydrothermally reacting at 145°C for 4h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0044] S3, adding 55g of the composite diatomaceous earth in step S2 to 1L of ethanol aqueous solution (the mass fraction of ethanol is 65%), then adding 10g of γ-aminopropyltriethoxysilane, stirring and reacting at 65°C for 2.5h. After the reaction is completed, filtering, washing, and drying to obtain the amino-modified composite diatomaceous earth;

[0045] S4, 7g of trans-3-(3-pyridyl)allylic acid was added to 800mL of N,N-dimethylformamide, followed by the addition of 25g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stirred for 30min before adding 50g of the amino-composite diatomaceous earth and 25g of N-hydroxysuccinimide in step S3, and reacted at 95°C for 4h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 50g of the solid product was added to 800mL of dimethyl sulfoxide, followed by the addition of 8g of 4-acrylamidebenzo-18-crown ether and 0.15g of ammonium persulfate, and the mixture was kept at a constant temperature for 1.5h at 105°C. After the reaction was completed, the mixture was filtered, washed, and dried to obtain the modified diatomaceous earth.

[0046] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0047] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, and the mixture is mixed and ground for 30 minutes, and dried at 85°C to obtain the composite treatment agent.

[0048] Example 2

[0049] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0050] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminium chloride, 15 parts of activated carbon, 8 parts of shell powder, 7 parts of polyacrylamide and 6 parts of sodium lauryl sulfate.

[0051] The preparation method of the modified diatomaceous earth comprises the following steps:

[0052] S1, 100g of diatomaceous earth was added to 1L of nitric acid aqueous solution with a mass concentration of 6%, and the mixture was immersed at 65°C for 1.5h, followed by filtering, washing, and drying to obtain acidified diatomaceous earth; then 100g of the acidified diatomaceous earth was added to a sodium hydroxide solution with a mass concentration of 6%, and heated at 65°C with stirring for 1.5h. After the treatment, the mixture was filtered, washed, dried, and calcined at 320°C for 1.5h to obtain pretreated diatomaceous earth;

[0053] S2, adding 20g of pretreated diatomaceous earth and 1.5g of Tween 20 in step S1 to 600mL of 0.7mol / L Ca(NO3)2 solution, followed by adding 400mL of 0.7mol / L KH2PO4 solution, and then adding 6% nitric acid dropwise to the solution, adjusting the pH to 2.5, ultrasonically dispersing for 30min, and then hydrothermally reacting at 145°C for 4h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0054] S3, adding 55g of the composite diatomaceous earth in step S2 to 1L of ethanol aqueous solution (the mass fraction of ethanol is 65%), then adding 10g of γ-aminopropyltriethoxysilane, stirring and reacting at 65°C for 2.5h. After the reaction is completed, filtering, washing, and drying to obtain the amino-modified composite diatomaceous earth;

[0055] S4, 6g of trans-3-(3-pyridyl)allylic acid was added to 800mL of N,N-dimethylformamide, followed by the addition of 23g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stirred for 30min before adding 50g of the amino-composite diatomaceous earth and 23g of N-hydroxysuccinimide in step S3, and reacted at 95°C for 4h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 50g of the solid product was added to 800mL of dimethyl sulfoxide, followed by the addition of 7g of 4-acrylamidebenzo-18-crown ether and 0.15g of ammonium persulfate, and the mixture was isothermally reacted at 105°C for 1.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain the modified diatomaceous earth.

[0056] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0057] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, and the mixture is mixed and ground for 30 minutes, and dried at 85°C to obtain the composite treatment agent.

[0058] Example 3

[0059] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0060] 50 parts of modified diatomaceous earth, 10 parts of zeolite powder, 10 parts of polyaluminium chloride, 10 parts of activated carbon, 5 parts of shell powder, 5 parts of polyacrylamide, and 4 parts of sodium lauryl sulfate.

[0061] The preparation method of the modified diatomaceous earth comprises the following steps:

[0062] S1, adding 100g of diatomaceous earth to 1L of 5% nitric acid aqueous solution, immersing at 60°C for 2h, then filtering, washing, and drying to obtain acidified diatomaceous earth; then adding 100g of acidified diatomaceous earth to 5% sodium hydroxide solution, stirring and heating at 60°C for 2h, filtering, washing, drying, and calcining at 300°C for 2h to obtain pretreated diatomaceous earth;

[0063] S2, adding 20g of pretreated diatomaceous earth and 1g of Tween 20 in step S1 to 500mL of 0.8mol / L Ca(NO3)2 solution, followed by adding 300mL of 0.8mol / L KH2PO4 solution, and then adding 5% nitric acid dropwise to the solution, adjusting the pH to 3, ultrasonically dispersing for 30min, and then hydrothermally reacting at 140°C for 5h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0064] S3, adding 50g of the composite diatomaceous earth in step S2 to 1L of ethanol aqueous solution (the mass fraction of ethanol is 60%), then adding 8g of γ-aminopropyltriethoxysilane, stirring and reacting at 60°C for 3h. After the reaction is completed, filtering, washing, and drying to obtain the amino-modified composite diatomaceous earth;

[0065] S4, 5g of trans-3-(3-pyridyl)allylic acid was added to 800mL of N,N-dimethylformamide, followed by the addition of 20g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stirred for 30min before adding 50g of the amino-composite diatomaceous earth and 20g of N-hydroxysuccinimide in step S3, and reacted at 90°C for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 50g of the solid product was added to 800mL of dimethyl sulfoxide, followed by the addition of 6g of 4-acrylamidebenzo-18-crown ether and 0.1g of ammonium persulfate, and the mixture was kept at a constant temperature for 2h at 100°C. After the reaction was completed, the mixture was filtered, washed, and dried to obtain the modified diatomaceous earth.

[0066] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0067] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, mixed and ground for 30 minutes, and dried at 80°C to obtain the composite treatment agent.

[0068] Example 4

[0069] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0070] 60 parts of modified diatomaceous earth, 20 parts of zeolite powder, 20 parts of polyaluminium chloride, 20 parts of activated carbon, 10 parts of shell powder, 10 parts of polyacrylamide and 8 parts of sodium lauryl sulfate.

[0071] The preparation method of the modified diatomaceous earth comprises the following steps:

[0072] S1, adding 100g of diatomaceous earth to 1L of 8% nitric acid aqueous solution, immersing at 70°C for 1h, then filtering, washing, and drying to obtain acidified diatomaceous earth; then adding 100g of acidified diatomaceous earth to 8% sodium hydroxide solution, stirring and heating at 70°C for 1h, filtering, washing, drying, and calcining at 350°C for 1h to obtain pretreated diatomaceous earth;

[0073] S2, adding 20g of pretreated diatomaceous earth and 2g of Tween 20 in step S1 to 800mL of 0.5mol / L Ca(NO3)2 solution, followed by adding 500mL of 0.5mol / L KH2PO4 solution, and then adding 8% nitric acid dropwise to the solution, adjusting the pH to 2, ultrasonically dispersing for 30min, and then hydrothermally reacting at 150°C for 3h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0074] S3, adding 60g of the composite diatomaceous earth in step S2 to 1L of ethanol aqueous solution (the mass fraction of ethanol is 70%), then adding 12g of γ-aminopropyltriethoxysilane, stirring and reacting at 70°C for 2h. After the reaction is completed, filtering, washing, and drying to obtain the amino-modified composite diatomaceous earth;

[0075] S4, 8g of trans-3-(3-pyridyl)allylic acid was added to 800mL of N,N-dimethylformamide, followed by the addition of 30g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stirred for 30min. Then, 50g of the amino-composite diatomaceous earth and 30g of N-hydroxysuccinimide in step S3 were added, and the mixture was reacted at 100°C for 3h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 50g of the solid product was added to 800mL of dimethyl sulfoxide, followed by the addition of 9g of 4-acrylamidebenzo-18-crown ether and 0.2g of ammonium persulfate. The mixture was reacted at a constant temperature of 110°C for 1h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain the modified diatomaceous earth.

[0076] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0077] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, and the mixture is mixed and ground for 30 minutes, and dried at 90°C to obtain the composite treatment agent.

[0078] Comparative Example 1

[0079] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0080] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminium chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide and 6 parts of sodium lauryl sulfate.

[0081] The preparation method of the modified diatomaceous earth comprises the following steps:

[0082] S1, 100g of diatomaceous earth was added to 1L of 7% nitric acid aqueous solution, immersed at 65°C for 1.5h, then filtered, washed, and dried to obtain acidified diatomaceous earth; then 100g of acidified diatomaceous earth was added to 7% sodium hydroxide solution, stirred and heated at 65°C for 1.5h, filtered, washed, dried, and calcined at 330°C for 1.5h to obtain pretreated diatomaceous earth;

[0083] S2, adding 20g of pretreated diatomaceous earth and 1.5g of Tween 20 in step S1 to 700mL of 0.6mol / L Ca(NO3)2 solution, followed by adding 400mL of 0.7mol / L KH2PO4 solution, and then adding 7% nitric acid dropwise to the solution, adjusting the pH to 2.5, ultrasonically dispersing for 30min, and then hydrothermally reacting at 145°C for 4h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0084] S3, adding 55g of the composite diatomaceous earth in step S2 to 1L of ethanol aqueous solution (the mass fraction of ethanol is 65%), then adding 10g of γ-aminopropyltriethoxysilane, stirring and reacting at 65°C for 2.5h. After the reaction is completed, filtering, washing, and drying to obtain the amino-modified composite diatomaceous earth;

[0085] S4. Add 7 g of trans-3-(3-pyridyl)allylic acid to 800 mL of N,N-dimethylformamide, followed by adding 25 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. After stirring for 30 min, add 50 g of the amino-composite diatomaceous earth and 25 g of N-hydroxysuccinimide in step S3, and react at 95 ° C. for 4 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0086] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0087] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, and the mixture is mixed and ground for 30 minutes, and dried at 85°C to obtain the composite treatment agent.

[0088] Compared with Example 1, in this comparative example, 4-acrylamidebenzo-18-crown ether was not introduced into the diatomaceous earth.

[0089] Comparative Example 2

[0090] A composite treatment agent for sewage, comprising the following raw materials in parts by weight:

[0091] 55 parts of modified diatomaceous earth, 15 parts of zeolite powder, 15 parts of polyaluminium chloride, 15 parts of activated carbon, 7 parts of shell powder, 8 parts of polyacrylamide and 6 parts of sodium lauryl sulfate.

[0092] The preparation method of the modified diatomaceous earth comprises the following steps:

[0093] S1, 100g of diatomaceous earth was added to 1L of 7% nitric acid aqueous solution, immersed at 65°C for 1.5h, then filtered, washed, and dried to obtain acidified diatomaceous earth; then 100g of acidified diatomaceous earth was added to 7% sodium hydroxide solution, stirred and heated at 65°C for 1.5h, filtered, washed, dried, and calcined at 330°C for 1.5h to obtain pretreated diatomaceous earth;

[0094] S2, adding 20g of pretreated diatomaceous earth and 1.5g of Tween 20 in step S1 to 700mL of 0.6mol / L Ca(NO3)2 solution, followed by adding 400mL of 0.7mol / L KH2PO4 solution, and then adding 7% nitric acid dropwise to the solution, adjusting the pH to 2.5, ultrasonically dispersing for 30min, and then hydrothermally reacting at 145°C for 4h. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain composite diatomaceous earth;

[0095] S3. Add 55 g of the composite diatomaceous earth in step S2 to 1 L of ethanol aqueous solution (the mass fraction of ethanol is 65%), then add 10 g of γ-aminopropyltriethoxysilane, and stir to react at 65° C. for 2.5 h. After the reaction is completed, filter, wash, and dry to obtain the modified diatomaceous earth.

[0096] A method for preparing a composite treatment agent for sewage, comprising the following steps:

[0097] The raw materials are weighed according to the formula, and modified diatomaceous earth, zeolite powder, polyaluminum chloride, activated carbon, shell powder, polyacrylamide, and sodium lauryl sulfate are mixed evenly. An equal amount of ethanol solution (mass concentration is 50%) is added, and the mixture is mixed and ground for 30 minutes, and dried at 85°C to obtain the composite treatment agent.

[0098] Compared with Example 1, in this comparative example, trans-3-(3-pyridyl)allylic acid and 4-acrylamidebenzo-18-crown ether were not introduced onto diatomaceous earth.

[0099] The adsorption performance of the composite treatment agent prepared in Examples 1-4 and Comparative Examples 1-2 on wastewater with complex components was tested respectively. The specific results are as follows: simulated wastewater was prepared. 2+ 、Cu 2+ , Pb 2+ The concentration of 500 mg / L, the methyl orange content is 100 mg / L, and the rhodamine B content is 100 mg / L. Take 6 500 mL conical flasks, add 200 mL of simulated wastewater to each conical flask, and then add 1 g of the composite treatment agent prepared in Examples 1-4 and Comparative Examples 1-2, respectively. Place in a constant temperature shaker and oscillate under natural light. Set the shaker temperature to 25 ° C, the speed to 250 rpm, and the oscillation time to 1 h. After the oscillation is completed, filter the solution through a microporous membrane, and then detect the concentration of each pollutant in the solution. The test is averaged 3 times to calculate the removal rate. The test results are shown in Table 1 below:

[0100] Table 1 Performance test results of each group of composite treatment agents

[0101]

[0102] As can be seen from Table 1, the composite treatment agent for sewage prepared by the present invention has good adsorption properties for heavy metals and organic pollutants, can quickly and efficiently adsorb heavy metal ions and organic pollutants in sewage, and has good application prospects.

[0103] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A composite treatment agent for sewage, characterized in that: Calculated by weight, it includes the following raw materials: 50-60 parts of modified diatomaceous earth, 10-20 parts of zeolite powder, 10-20 parts of polyaluminium chloride, 10-20 parts of activated carbon, 5-10 parts of shell powder, 5-10 parts of polyacrylamide, 4-8 parts of sodium lauryl sulfate; The preparation method of the modified diatomaceous earth comprises the following steps: S1, adding diatomaceous earth to an aqueous nitric acid solution, filtering, washing, and drying after immersion treatment to obtain acidified diatomaceous earth; then adding the acidified diatomaceous earth to a sodium hydroxide solution, stirring and heating, filtering, washing, drying, and calcining after the treatment to obtain pretreated diatomaceous earth; S2, adding the pretreated diatomaceous earth and Tween 20 in step S1 to a Ca(NO3)2 solution, followed by a KH2PO4 solution, and then dropping nitric acid into the solution to adjust the pH to 2-3. After ultrasonic dispersion, a hydrothermal reaction is performed. After the reaction is completed, the mixture is allowed to stand, filtered, washed, and dried to obtain a composite diatomaceous earth; S3, adding the composite diatomaceous earth in step S2 to an ethanol aqueous solution, then adding γ-aminopropyltriethoxysilane, stirring to react, and filtering, washing, and drying after the reaction is completed to obtain an amino-modified composite diatomaceous earth; S4. Add trans-3-(3-pyridyl)allylic acid to N,N-dimethylformamide, then add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and stir for 30 minutes. Then add the amino-composite diatomite and N-hydroxysuccinimide in step S3 to carry out heating reaction. After the reaction is completed, filter, wash, and dry to obtain a solid product. Subsequently, add the solid product to dimethyl sulfoxide, and then add 4-acrylamidebenzo-18-crown ether and ammonium persulfate to carry out constant temperature reaction. After the reaction is completed, filter, wash, and dry to obtain the modified diatomite.

2. The composite treatment agent for sewage according to claim 1, characterized in that: Calculated by weight, it includes the following raw materials: 55-60 parts of modified diatomaceous earth, 15-20 parts of zeolite powder, 10-15 parts of polyaluminium chloride, 10-15 parts of activated carbon, 7-10 parts of shell powder, 5-8 parts of polyacrylamide, and 4-6 parts of sodium lauryl sulfate.

3. The composite treatment agent for sewage according to claim 1, characterized in that: The particle size of the zeolite powder is 300-400 μm; the particle size of the activated carbon is 100-200 μm; and the particle size of the shell powder is 0.5-2 mm.

4. The composite treatment agent for sewage according to claim 1, characterized in that: The mass concentration of the nitric acid aqueous solution in step S1 is 5-8%, the temperature of the immersion treatment is 60-70°C, and the time is 1-2h; the mass concentration of the sodium hydroxide solution is 5-8%, the temperature of the stirring and heating treatment is 60-70°C, and the time is 1-2h; the temperature of the roasting is 300-350°C, and the time is 1-2h.

5. The composite treatment agent for sewage according to claim 1, characterized in that: The concentration of the Ca(NO3)2 solution in step S2 is 0.5-0.8 mol / L, the concentration of the KH2PO4 solution is 0.5-0.8 mol / L, the mass volume ratio of the pretreated diatomaceous earth, Tween 20, Ca(NO3)2 solution, and KH2PO4 solution is 20 g:1-2 g:500-800 mL:300-500 mL, the temperature of the hydrothermal reaction is 140-150 ° C, and the time is 3-5 h.

6. The composite treatment agent for sewage according to claim 1, characterized in that: In step S3, the mass fraction of ethanol in the ethanol aqueous solution is 60-70%, the mass ratio of the composite diatomaceous earth and γ-aminopropyltriethoxysilane is 50-60:8-12, the stirring reaction temperature is 60-70° C., and the time is 2-3 hours.

7. The composite treatment agent for sewage according to claim 1, characterized in that: In step S4, the mass ratio of the amino-composite diatomaceous earth, trans-3-(3-pyridyl)allylic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and N-hydroxysuccinimide is 50:5-8:20-30:20-30, the temperature of the heating reaction is 90-100°C, and the time is 3-5h; the mass ratio of the solid product, 4-acrylamidebenzo-18-crown ether, and ammonium persulfate is 50:6-9:0.1-0.2, the temperature of the constant temperature reaction is 100-110°C, and the time is 1-2h.

8. A method for preparing a composite treatment agent for sewage according to any one of claims 1 to 7, characterized in that: The following steps are involved: The raw materials are weighed according to the formula, and the modified diatomaceous earth, zeolite powder, polyaluminium chloride, activated carbon, shell powder, polyacrylamide, sodium lauryl sulfate and ethanol solution are mixed and ground, and dried at 80-90° C. to obtain the composite treatment agent.

9. Use of the composite treating agent for sewage according to any one of claims 1 to 7 in treating chemical sewage.

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