Decolorizing agent for wastewater treatment and preparation method thereof

Abstract

The invention discloses a decolorizing agent for wastewater treatment and a preparation method thereof, and belongs to the technical field of sewage treatment. The decolorizing agent for wastewater treatment comprises the following components in parts by mass: 40-60 parts of modified molecular sieve, 10-30 parts of polyaluminium chloride and 2-5 parts of anionic polyacrylamide. The invention combines the characteristics of inorganic and organic flocculants, relies on the synergistic effect of multiple flocculants, improves the adsorption capacity of the decolorizing agent for wastewater treatment on wastewater pollutant components, cooperates with each other, can quickly decolorize industrial wastewater, improves water treatment efficiency and reduces costs. The invention significantly improves the decolorization effect of the decolorizing agent for wastewater treatment on wastewater by modifying the molecular sieve.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a decolorizing agent for wastewater treatment and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization, various types of industrial wastewater contain a large amount of difficult-to-degrade organic dyes and pigment pollutants, which seriously affect the environment and ecology. How to effectively treat these colored wastewaters has become one of the important challenges facing the field of modern environmental protection. At present, the main methods for wastewater decolorization are: biochemical method, physical adsorption method, chemical oxidation method, etc. Among them, chemical adsorption method has attracted widespread attention due to its simple operation and good decolorization effect. Commonly used adsorbents include activated carbon, natural clay and ion exchange fiber, but these materials have limited adsorption performance and are difficult to recycle.

[0003] Chinese patent 201711026787.9 provides a method for preparing a high-viscosity dicyandiamide-formaldehyde polycondensate catalyzed by aluminum sulfate suitable for decolorizing dye wastewater, and through the optimization of raw material selection and process conditions, the prepared dicyandiamide formaldehyde has a broad-spectrum and efficient application effect. However, the dicyandiamide formaldehyde polycondensate synthesized by this method has a limited decolorization effect due to its small molecular weight, limited cationicity, and single composition. Summary of the invention

[0004] The main purpose of the present invention is to provide a decolorizing agent for wastewater treatment and a preparation method thereof. The decolorizing agent for wastewater treatment prepared by the present invention combines the characteristics of inorganic and organic flocculants, relies on the synergistic effect of multiple flocculants, and significantly improves the adsorption capacity of the decolorizing agent for wastewater treatment on wastewater pollutant components. The components cooperate with each other to quickly decolorize industrial wastewater, thereby improving water treatment efficiency.

[0005] To achieve the above object, the present invention provides a decolorizing agent for wastewater treatment, comprising the following components in parts by mass: 40-60 parts of modified molecular sieve, 10-30 parts of polyaluminium chloride, and 2-5 parts of anionic polyacrylamide.

[0006] Preferably, the preparation method of the modified molecular sieve is as follows:

[0007] (1) adding molecular sieve to an ethanol aqueous solution, adding allyltrimethoxysilane, heating and stirring to react, filtering, washing, and drying after the reaction is completed to obtain an allyl molecular sieve composite;

[0008] (2) adding the allyl molecular sieve complex to thionyl chloride, adding acryloyloxyethyl trimethyl ammonium chloride, 2-mercaptobenzothiazole, and azobisisobutyronitrile, and heating to react. After the reaction is completed, filtering, washing, and drying to obtain a modified molecular sieve.

[0009] Preferably, in step (1), the mass ratio of molecular sieve to allyltrimethoxysilane is 20-30:3-5; the heating temperature is 40-60° C., and the reaction time is 3-5 h.

[0010] Preferably, in step (2), the mass ratio of the allyl molecular sieve complex, acryloyloxyethyl trimethyl ammonium chloride and 2-mercaptobenzothiazole is 3-5:1-2:1-2; the heating temperature is 60-80° C., and the heating time is 4-6 h.

[0011] Further preferably, the molecular sieve needs to be pretreated before use, and the treatment method is as follows:

[0012] Manganese nitrate hexahydrate and 2-aminoterephthalic acid are added to N,N-dimethylformamide and mixed evenly, and then molecular sieves are added and heated to react after being evenly dispersed. After the reaction is completed, the pretreated molecular sieves are obtained by filtering, washing and drying.

[0013] Preferably, the mass ratio of manganese nitrate hexahydrate, 2-aminoterephthalic acid and molecular sieve is 5-8:3-6:15-20; the reaction temperature is 100-120° C., and the reaction time is 6-10 h.

[0014] The invention also discloses a preparation method of the decolorizing agent for wastewater treatment, which comprises the following steps: weighing each component according to the formula, and then mixing and stirring the modified molecular sieve, polyaluminium chloride and anionic polyacrylamide evenly.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The present invention combines the characteristics of inorganic and organic flocculants, and relies on the synergistic effect of multiple flocculants to significantly improve the adsorption capacity of the decolorizer for wastewater treatment on wastewater pollutant components. The components cooperate with each other to quickly decolorize industrial wastewater, thereby improving water treatment efficiency and reducing costs;

[0017] 2) The modified molecular sieve of the present invention uses 13X molecular sieve as an adsorption carrier, has a high specific surface area and porosity, and can adsorb organic pollutants in wastewater, but its adsorption performance for organic matter in wastewater is limited. The present invention first loads the manganese-based MOF material on the surface of the molecular sieve by a heating synthesis method, which increases the specific surface area of ​​the molecular sieve and increases the contact area between the wastewater decolorizer and the wastewater to be treated, thereby improving the decolorization efficiency. On the other hand, the manganese-based MOF material has a good adsorption effect on organic matter in wastewater, thereby improving the adsorption performance of the molecular sieve for organic matter in wastewater; the surface is treated with allyltrimethoxysilane, Active carbon-carbon double bonds can be introduced on its surface, which is beneficial to subsequent reactions. 2-mercaptobenzothiazole and cationic compound acryloyloxyethyltrimethylammonium chloride are then grafted on the surface of the molecular sieve. The thiazole group and carboxyl group in the 2-mercaptobenzothiazole molecule can coordinate with metal ions in the water very well, thereby removing the metal ions in the water. The cationic compound acryloyloxyethyltrimethylammonium chloride can play the role of a cationic flocculant, neutralize the negative charge on the surface of suspended particles or colloid particles, reduce their surface potential, weaken the electrostatic repulsion between particles, and promote flocculation. By modifying the molecular sieve, the decolorization effect of the decolorizer for wastewater treatment on wastewater can be greatly improved. DETAILED DESCRIPTION

[0018] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0019] The sources of some raw materials used in the present invention are as follows:

[0020] 13X molecular sieve, pore size 10A, diameter 3-5 mm, purchased from Pingxiang Xinrui Chemical Technology Co., Ltd.

[0021] Anionic polyacrylamide, with a molecular weight of 8-22 million, was purchased from Zhengzhou Zhuohang Water Purification Materials Co., Ltd.

[0022] Example 1

[0023] A method for preparing a decolorizing agent for wastewater treatment comprises the following steps:

[0024] (1) 32 g of manganese nitrate hexahydrate and 23 g of 2-aminoterephthalic acid were added to 300 mL of N,N-dimethylformamide and mixed evenly. Then, 87 g of 13X molecular sieve was added and the mixture was evenly dispersed and heated at 120° C. for 8 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a pretreated molecular sieve.

[0025] (2) Add 25.8 g of the pretreated molecular sieve to 200 mL of a 50 wt% ethanol aqueous solution, add 4.4 g of allyltrimethoxysilane, heat and stir at 50 °C for 4 h, filter, wash and dry after the reaction is complete to obtain an allyl molecular sieve composite;

[0026] (3) 12 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, and 4.5 g of acryloyloxyethyl trimethylammonium chloride, 4.4 g of 2-mercaptobenzothiazole, and 0.4 g of azobisisobutyronitrile were added, and the mixture was heated at 70 °C for 5 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a modified molecular sieve;

[0027] (4) 50 g of modified molecular sieve, 20.5 g of polyaluminium chloride and 3.5 g of anionic polyacrylamide were mixed and stirred to obtain the decolorizing agent for wastewater treatment.

[0028] Example 2

[0029] A method for preparing a decolorizing agent for wastewater treatment comprises the following steps:

[0030] (1) Add 25 g of manganese nitrate hexahydrate and 15 g of 2-aminoterephthalic acid to 300 mL of N,N-dimethylformamide and mix well. Then add 75 g of 13X molecular sieve and heat at 100 °C for 6 h after the dispersion is evenly dispersed. After the reaction is completed, filter, wash and dry to obtain a pretreated molecular sieve.

[0031] (2) Add 20.5 g of the pretreated molecular sieve to 200 mL of a 50 wt% ethanol aqueous solution, add 3.2 g of allyltrimethoxysilane, heat and stir at 40 °C for 3 h, filter, wash and dry after the reaction is complete to obtain an allyl molecular sieve composite;

[0032] (3) 9 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, and 3 g of acryloyloxyethyl trimethylammonium chloride, 3.1 g of 2-mercaptobenzothiazole, and 0.3 g of azobisisobutyronitrile were added, and the mixture was heated at 60 °C for 4 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a modified molecular sieve;

[0033] (4) 40.6 g of modified molecular sieve, 10 g of polyaluminium chloride and 20 g of anionic polyacrylamide were mixed and stirred uniformly to obtain the decolorizing agent for wastewater treatment.

[0034] Example 3

[0035] A method for preparing a decolorizing agent for wastewater treatment comprises the following steps:

[0036] (1) 40 g of manganese nitrate hexahydrate and 30 g of 2-aminoterephthalic acid were added to 300 mL of N,N-dimethylformamide and mixed evenly. Then, 100 g of 13X molecular sieve was added and the mixture was evenly dispersed and heated at 120° C. for 8 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a pretreated molecular sieve.

[0037] (2) Add 30 g of the pretreated molecular sieve to 200 mL of 50 wt% ethanol aqueous solution, add 5 g of allyltrimethoxysilane, heat and stir at 60 °C for 5 h, filter, wash and dry after the reaction is completed to obtain an allyl molecular sieve composite;

[0038] (3) 15 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, and 6 g of acryloyloxyethyl trimethylammonium chloride, 6 g of 2-mercaptobenzothiazole, and 0.5 g of azobisisobutyronitrile were added, and the mixture was heated at 80 °C for 6 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a modified molecular sieve;

[0039] (4) 60 g of modified molecular sieve, 30 g of polyaluminium chloride and 50 g of anionic polyacrylamide were mixed and stirred uniformly to obtain the decolorizing agent for wastewater treatment.

[0040] Comparative Example 1

[0041] A method for preparing a decolorizing agent for wastewater treatment is similar to Example 1, except that 2-mercaptobenzothiazole is not added, and specifically comprises the following steps:

[0042] (1) 32 g of manganese nitrate hexahydrate and 23 g of 2-aminoterephthalic acid were added to 300 mL of N,N-dimethylformamide and mixed evenly. Then, 87 g of 13X molecular sieve was added and the mixture was evenly dispersed and heated at 120° C. for 8 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a pretreated molecular sieve.

[0043] (2) Add 25.8 g of the pretreated molecular sieve to 200 mL of a 50 wt% ethanol aqueous solution, add 4.4 g of allyltrimethoxysilane, heat and stir at 50 °C for 4 h, filter, wash and dry after the reaction is complete to obtain an allyl molecular sieve composite;

[0044] (3) 12 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, 4.5 g of acryloyloxyethyl trimethylammonium chloride and 0.4 g of azobisisobutyronitrile were added, and the mixture was heated at 70 °C for 5 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a modified molecular sieve;

[0045] (4) 50 g of modified molecular sieve, 20.5 g of polyaluminium chloride and 3.5 g of anionic polyacrylamide were mixed and stirred to obtain the decolorizing agent for wastewater treatment.

[0046] Comparative Example 2

[0047] A method for preparing a decolorizing agent for wastewater treatment, similar to Example 1, except that acryloyloxyethyl trimethyl ammonium chloride is not added, comprises the following steps:

[0048] (1) 32 g of manganese nitrate hexahydrate and 23 g of 2-aminoterephthalic acid were added to 300 mL of N,N-dimethylformamide and mixed evenly. Then, 87 g of 13X molecular sieve was added and the mixture was evenly dispersed and heated at 120° C. for 8 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a pretreated molecular sieve.

[0049] (2) Add 25.8 g of the pretreated molecular sieve to 200 mL of a 50 wt% ethanol aqueous solution, add 4.4 g of allyltrimethoxysilane, heat and stir at 50 °C for 4 h, filter, wash and dry after the reaction is complete to obtain an allyl molecular sieve composite;

[0050] (3) 12 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, 4.4 g of 2-mercaptobenzothiazole and 0.4 g of azobisisobutyronitrile were added, and the mixture was heated at 70 °C for 5 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a modified molecular sieve;

[0051] (4) 50 g of modified molecular sieve, 20.5 g of polyaluminium chloride and 3.5 g of anionic polyacrylamide were mixed and stirred to obtain the decolorizing agent for wastewater treatment.

[0052] Comparative Example 3

[0053] A method for preparing a decolorizing agent for wastewater treatment is similar to Example 1, except that the molecular sieve is not pretreated before use, and specifically comprises the following steps:

[0054] (1) Add 25.8 g of 13X molecular sieve to 200 mL of 50 wt% ethanol aqueous solution, add 4.4 g of allyl trimethoxysilane, heat and stir at 50 °C for 4 h, filter, wash and dry after the reaction is completed to obtain an allyl molecular sieve composite;

[0055] (2) 12 g of the allyl molecular sieve complex was dispersed in 200 mL of dichlorothionyl, and 4.5 g of acryloyloxyethyl trimethylammonium chloride, 4.4 g of 2-mercaptobenzothiazole, and 0.4 g of azobisisobutyronitrile were added, and the mixture was heated at 70 ° C for 5 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a modified molecular sieve;

[0056] (3) 50 g of modified molecular sieve, 20.5 g of polyaluminium chloride and 3.5 g of anionic polyacrylamide were mixed and stirred uniformly to obtain the decolorizing agent for wastewater treatment.

[0057] Performance Testing

[0058] Take 150mL of industrial wastewater (pH=7.6, COD=506.8mg / L, chromaticity 403, conductivity 0.94×10 3 μS‧cm -1 ), respectively placed in 250mL conical flasks, added thereto at 25°C the decolorizing agents for wastewater treatment prepared in Examples 1-3 and Comparative Examples 1-3, and shaken for 20 minutes before standing to test COD removal rate and decolorization rate. The COD (chemical oxygen demand) was determined according to HJ828-2017 "Determination of Chemical Oxygen Demand of Water Quality - Dichromate Method", and the decolorization rate was determined by UV-visible spectrophotometry. The test results are shown in Table 1:

[0059] Table 1 Performance test results of decolorizing agent for wastewater treatment

[0060]

[0061] It can be seen from the experimental results in Table 1 that the decolorizing agent for wastewater treatment prepared by the present invention has a good removal effect on pollutants in wastewater.

[0062] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A decolorizing agent for wastewater treatment, characterized in that: The invention comprises the following components in parts by mass: 40-60 parts of modified molecular sieve, 10-30 parts of polyaluminium chloride and 2-5 parts of anionic polyacrylamide; The preparation method of the modified molecular sieve is as follows: (1) adding molecular sieve to an ethanol aqueous solution, adding allyltrimethoxysilane, heating and stirring to react, filtering, washing, and drying after the reaction is completed to obtain an allyl molecular sieve composite; (2) adding the allyl molecular sieve complex to thionyl chloride, adding acryloyloxyethyl trimethyl ammonium chloride, 2-mercaptobenzothiazole, and azobisisobutyronitrile, and heating to react. After the reaction is completed, filtering, washing, and drying to obtain a modified molecular sieve; In the step (1), the mass ratio of molecular sieve to allyltrimethoxysilane is 20-30:3-5; In the step (2), the mass ratio of the allyl molecular sieve complex, acryloyloxyethyl trimethyl ammonium chloride and 2-mercaptobenzothiazole is 3-5:1-2:1-2.

2. The decolorizing agent for wastewater treatment according to claim 1, characterized in that: The heating temperature in step (1) is 40-60° C. and the reaction time is 3-5 h.

3. The decolorizing agent for wastewater treatment according to claim 1, characterized in that: In the step (2), the heating temperature is 60-80° C. and the heating time is 4-6 hours.

4. The decolorizing agent for wastewater treatment according to claim 1, characterized in that The molecular sieve needs to be pretreated before use, and the treatment method is as follows: Manganese nitrate hexahydrate and 2-aminoterephthalic acid are added to N,N-dimethylformamide and mixed evenly, and then molecular sieves are added and heated to react after being evenly dispersed. After the reaction is completed, the pretreated molecular sieves are obtained by filtering, washing and drying.

5. The decolorizing agent for wastewater treatment according to claim 4, characterized in that: The mass ratio of the manganese nitrate hexahydrate, 2-aminoterephthalic acid and molecular sieve is 5-8:3-6:15-20.

6. The decolorizing agent for wastewater treatment according to claim 4, characterized in that: The reaction temperature is 100-120° C., and the reaction time is 6-10 h.

7. A method for preparing a decolorizing agent for wastewater treatment according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: mixing and stirring the modified molecular sieve, polyaluminium chloride and anionic polyacrylamide evenly.

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