Polyaluminum chloride water purifying agent and preparation method thereof

Abstract

The invention relates to the technical field of water purification, in particular to a polyaluminum chloride water purifying agent and a preparation method thereof. According to the polyaluminum chloride water purifying agent, molecular-level hybridization and function synergy are achieved through in-situ compounding of polyaminated ferroferric oxide and aluminum chloride, so that the water purifying performance is remarkably improved, and the specific steps include: (1) conducting amination modification on ferroferric oxide; (2) carrying out polyamination treatment on the aminated ferroferric oxide; and (3) carrying out hydrolytic polymerization on the polyaminated ferroferric oxide and aluminum chloride, and aging. And the product has a magnetic separation function, and is suitable for high-difficulty industrial wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of water purification, and in particular to a polyaluminium chloride water purifier and a preparation method thereof. Background Art

[0002] A flocculant is a water treatment agent that aggregates colloidal matter and particulate matter suspended in a liquid, forming a larger flocculent structure. This then causes these particles to settle from a stable suspension, increasing the settling rate of impurity particles in the water and improving water clarity. Based on their chemical properties, flocculants can be divided into five main categories: inorganic, organic, biological, composite, and compound. Polyaluminum chloride (PAC), a commonly used inorganic polymer flocculant, is widely used in the treatment of drinking water, municipal wastewater, and industrial wastewater from chemical, metallurgical, and petroleum industries due to its excellent flocculation properties, rapid settling rate, strong adaptability, low dosage, and low water purification costs.

[0003] Patent document CN114195176B discloses a process for preparing a polyaluminum chloride water purifier. The polyaluminum chloride produced by this invention has advantages such as low impurity content and high purity. Patent document CN112850765B also discloses a method for controlling the quality of polyaluminum ferric chloride produced from aluminum ash. This invention not only eliminates the environmental pollution caused by the aluminum ash itself, but also prevents secondary water pollution caused by the produced polyaluminum ferric chloride during use. However, the water purification and flocculation effects of both methods need to be improved. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a polyaluminum chloride water purifier and a preparation method thereof, so as to provide a polyaluminum chloride water treatment agent with excellent water purification function.

[0005] Based on the above purpose, the present invention provides a method for preparing a polyaluminum chloride water purifier, comprising the following steps:

[0006] S1: Add ferrosoferric oxide to an ethanol aqueous solution, ultrasonically disperse for 20 minutes, then add ammonia water, stir for 10 minutes, then add tetraethyl orthosilicate and 3-aminopropyltriethoxysilane, stir and react for 6 hours, centrifuge, wash, and dry to obtain amino ferrosoferric oxide;

[0007] S2: Add aminated ferrosoferric oxide to methanol, ultrasonically disperse for 30 minutes, then add methyl acrylate dropwise, stir and react at room temperature for 24 hours, then add tetraethylene pentamine and double-terminated amino polyethylene glycol, raise the temperature to 50-55°C, stir and react for 12 hours to obtain polyaminated ferrosoferric oxide;

[0008] S3: Add polyamine ferrosoferric oxide to deionized water, ultrasonically disperse for 30 minutes, then add aluminum chloride, stir for 30 minutes, adjust the pH to 3-4 with hydrochloric acid, heat to 60-65°C, hydrolyze for 1-2 hours, then heat to 80-85°C, polymerize for 1-2 hours, cool to room temperature, age for 24 hours, centrifuge, and dry to obtain a polyaluminum chloride water purifier;

[0009] The ratio of the amount of ferrosilicate, ethanol aqueous solution, ammonia water, tetraethyl orthosilicate, and 3-aminopropyltriethoxysilane used in step S1 is 5-6g:500-600g:10-12g:12-14g:2-3g;

[0010] In step S2, the ratio of the amount of amination ferrosoferric oxide, methanol, methyl acrylate, tetraethylene pentamine, and double-terminated amino polyethylene glycol is 5-6 g: 500-550 g: 0.5-0-6 g: 1.5-1.8 g: 1-1.5 g;

[0011] In step S3, the usage ratio of polyamine ferrosoferric oxide, deionized water, and aluminum chloride is 4-5g:500-600g:20-25g.

[0012] Preferably, the average particle size of the ferrosoferric oxide in step S1 is 300-400 nm.

[0013] Preferably, the concentration of the ethanol aqueous solution in step S1 is 80 wt%-85 wt%.

[0014] Preferably, the concentration of the ammonia water in step S1 is 28 wt%-30 wt%.

[0015] Preferably, the weight average molecular weight of the double-terminated amino polyethylene glycol in step S2 is 1000.

[0016] Preferably, the pH is adjusted in step S3 using hydrochloric acid.

[0017] Furthermore, the present invention also provides a polyaluminium chloride water purifier.

[0018] Beneficial effects of the present invention:

[0019] The polyaluminium chloride water purifier of the present invention has excellent water purification ability, a high COD removal rate in sewage, can significantly improve the light transmittance of sewage, and has a good water purification effect.

[0020] The polyaluminium chloride water purifier of the present invention involves ferroferric oxide in the polymerization process of aluminium chloride, so that ferroferric oxide can form a molecular-level composite with polyaluminium chloride and simultaneously form multi-nuclear active sites, thereby enhancing the electrostatic effect and chemical bridging effect thereof.

[0021] The polyaluminium chloride water purifier of the present invention can form a tighter and more extensive dendritic cross-linked network by polyaminated ferrosoferric oxide with tetraethylene pentamine and double-terminated amino polyethylene glycol, thereby enhancing the adsorption of free impurities and particles in water and enhancing the "bridging" and "netting" effects. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0023] Example 1: A polyaluminium chloride water purifier, the specific preparation steps are as follows:

[0024] (1) 5 g of ferrosoferric oxide (average particle size 300 nm) was added to 500 g of ethanol aqueous solution (concentration 80 wt%), ultrasonically dispersed for 20 min, then 10 g of ammonia water (28 wt%) was added, stirred for 10 min, then 12 g of tetraethyl orthosilicate and 2 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0025] (2) Add 5 g of amino-ferroferric oxide to 500 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.5 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.5 g of tetraethylene pentamine and 1 g of double-terminated amino polyethylene glycol (weight-average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamine-ferroferric oxide;

[0026] (3) Add 4 g of polyamine ferrosoferric oxide to 500 g of deionized water, ultrasonically disperse for 30 min, then add 20 g of aluminum chloride, stir for 30 min, adjust the pH to 3.1 with hydrochloric acid, heat to 60 ° C, hydrolyze for 1 h, then heat to 80 ° C, polymerize for 1 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0027] Example 2: A polyaluminium chloride water purifier, the specific preparation steps are as follows:

[0028] (1) 5.5 g of ferrosoferric oxide (average particle size 300 nm) was added to 550 g of ethanol aqueous solution (concentration 83 wt%), ultrasonically dispersed for 20 min, then 11 g of ammonia water (28 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.5 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0029] (2) Add 5.5 g of aminoferric oxide to 520 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.55 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.7 g of tetraethylene pentamine and 1.3 g of double-terminated amino polyethylene glycol (weight-average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamined ferric oxide;

[0030] (3) Add 4.5 g of polyamine ferrosoferric oxide to 550 g of deionized water, ultrasonically disperse for 30 min, then add 23 g of aluminum chloride, stir for 30 min, adjust the pH to 3.4 with hydrochloric acid, heat to 63 ° C, hydrolyze for 2 h, then heat to 83 ° C, polymerize for 2 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0031] Example 3: A polyaluminium chloride water purifier, the specific preparation steps are as follows:

[0032] (1) 5.8 g of ferrosoferric oxide (average particle size 400 nm) was added to 500 g of ethanol aqueous solution (concentration 85 wt%), ultrasonically dispersed for 20 min, then 12 g of ammonia water (30 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.7 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0033] (2) Add 5.5 g of amino-ferroferric oxide to 550 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.6 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.6 g of tetraethylene pentamine and 1.4 g of double-terminated amino polyethylene glycol (weight-average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamine-ferroferric oxide;

[0034] (3) Add 5 g of polyamine ferrosoferric oxide to 500 g of deionized water, ultrasonically disperse for 30 min, then add 24 g of aluminum chloride, stir for 30 min, adjust the pH to 3.8 with hydrochloric acid, heat to 65 ° C, hydrolyze for 1 h, then heat to 85 ° C, polymerize for 1 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0035] Example 4: A polyaluminium chloride water purifier, the specific preparation steps are as follows:

[0036] (1) 6 g of ferrosoferric oxide (average particle size 400 nm) was added to 600 g of ethanol aqueous solution (concentration 85 wt%), ultrasonically dispersed for 20 min, then 12 g of ammonia water (30 wt%) was added, stirred for 10 min, then 14 g of tetraethyl orthosilicate and 3 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0037] (2) Add 6 g of aminoferric oxide to 550 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.6 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.8 g of tetraethylene pentamine and 1.5 g of double-terminated amino polyethylene glycol (weight-average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamined ferric oxide;

[0038] (3) Add 5 g of polyamine ferrosoferric oxide to 600 g of deionized water, ultrasonically disperse for 30 min, then add 25 g of aluminum chloride, stir for 30 min, adjust the pH to 4 with hydrochloric acid, heat to 65 ° C, hydrolyze for 2 h, then heat to 85 ° C, polymerize for 2 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0039] Comparative Example 1: The difference from Example 2 is that tetraethylenepentamine is not added in step (2). The specific preparation steps are as follows:

[0040] (1) 5.5 g of ferrosoferric oxide (average particle size 300 nm) was added to 550 g of ethanol aqueous solution (concentration 83 wt%), ultrasonically dispersed for 20 min, then 11 g of ammonia water (28 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.5 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0041] (2) Add 5.5 g of amino-ferroferric oxide to 520 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.55 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.3 g of double-terminated amino polyethylene glycol (weight average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamine-ferroferric oxide;

[0042] (3) Add 4.5 g of polyamine ferrosoferric oxide to 550 g of deionized water, ultrasonically disperse for 30 min, then add 23 g of aluminum chloride, stir for 30 min, adjust the pH to 3.4 with hydrochloric acid, heat to 63 ° C, hydrolyze for 2 h, then heat to 83 ° C, polymerize for 2 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0043] Comparative Example 2: The difference from Example 2 is that double-terminated amino polyethylene glycol is not added in step (2). The specific preparation steps are as follows:

[0044] (1) 5.5 g of ferrosoferric oxide (average particle size 300 nm) was added to 550 g of ethanol aqueous solution (concentration 83 wt%), ultrasonically dispersed for 20 min, then 11 g of ammonia water (28 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.5 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0045] (2) Add 5.5 g of aminoferric oxide to 520 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.55 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.7 g of tetraethylene pentamine, heat to 50 ° C, stir and react for 12 h to obtain polyamined ferric oxide;

[0046] (3) Add 4.5 g of polyamine ferrosoferric oxide to 550 g of deionized water, ultrasonically disperse for 30 min, then add 23 g of aluminum chloride, stir for 30 min, adjust the pH to 3.4 with hydrochloric acid, heat to 63 ° C, hydrolyze for 2 h, then heat to 83 ° C, polymerize for 2 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0047] Comparative Example 3: The difference from Example 2 is that only ethylenediamine is added in step (2). The specific preparation steps are as follows:

[0048] (1) 5.5 g of ferrosoferric oxide (average particle size 300 nm) was added to 550 g of ethanol aqueous solution (concentration 83 wt%), ultrasonically dispersed for 20 min, then 11 g of ammonia water (28 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.5 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0049] (2) Add 5.5 g of aminoferric oxide to 520 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.55 g of methyl acrylate, stir and react at room temperature for 24 h, then add 3 g of ethylenediamine, heat to 50 ° C, stir and react for 12 h to obtain polyamined ferric oxide;

[0050] (3) Add 4.5 g of polyamine ferrosoferric oxide to 550 g of deionized water, ultrasonically disperse for 30 min, then add 23 g of aluminum chloride, stir for 30 min, adjust the pH to 3.4 with hydrochloric acid, heat to 63 ° C, hydrolyze for 2 h, then heat to 83 ° C, polymerize for 2 h, cool to room temperature, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0051] Comparative Example 4: The difference from Example 2 is that aluminum chloride is first polymerized, and after the polymerization is completed, polyamine ferrosoferric oxide is added. The specific preparation steps are as follows:

[0052] (1) 5.5 g of ferrosoferric oxide (average particle size 300 nm) was added to 550 g of ethanol aqueous solution (concentration 83 wt%), ultrasonically dispersed for 20 min, then 11 g of ammonia water (28 wt%) was added, stirred for 10 min, then 13 g of tetraethyl orthosilicate and 2.5 g of 3-aminopropyltriethoxysilane were added, stirred for 6 h, centrifuged, washed, and dried to obtain amino-ferrosoferric oxide;

[0053] (2) Add 5.5 g of aminoferric oxide to 520 g of methanol, ultrasonically disperse for 30 min, then dropwise add 0.55 g of methyl acrylate, stir and react at room temperature for 24 h, then add 1.7 g of tetraethylene pentamine and 1.3 g of double-terminated amino polyethylene glycol (weight-average molecular weight 1000), heat to 50 ° C, stir and react for 12 h to obtain polyamined ferric oxide;

[0054] (3) Add 23 g of aluminum chloride to 550 g of deionized water, ultrasonically disperse for 30 min, adjust the pH to 3.4 with hydrochloric acid, heat to 63 ° C, hydrolyze for 2 h, then heat to 83 ° C, polymerize for 2 h, cool to room temperature, add 4.5 g of polyamine ferrosoferric oxide, stir for 30 min, age for 24 h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0055] Comparative Example 5: The difference from Example 2 is that aluminum chloride is polymerized first, and after the polymerization is completed, ferrosoferric oxide is added. The specific preparation steps are as follows:

[0056] Add 23g of aluminum chloride to 550g of deionized water, ultrasonically disperse for 30min, adjust the pH to 3.4 with hydrochloric acid, heat to 63°C, hydrolyze for 2h, then heat to 83°C, polymerize for 2h, cool to room temperature, add 4.5g of ferrosoferric oxide, stir for 30min, age for 24h, centrifuge, and dry to obtain a polyaluminum chloride water purifier.

[0057] Performance Testing

[0058] 1100g of Yellow River water was taken, stirred at high speed and then quickly divided evenly into 11 beakers. The beakers were numbered as Examples 1-4, Comparative Examples 1-5 and Control Groups 1-2. The polyaluminum chloride water purifiers prepared in the Examples and Comparative Examples were added to the beaker samples of the Examples and Comparative Examples according to the numbers. Control Group 1 was added with a commercially available polyaluminum chloride water purifier, and Control Group 2 was added with deionized water of the same weight as the water purifier. The water treatment quality added in the Examples, Comparative Examples and Control Group 1 was the same; after addition, the water was stirred at a speed of 50r / min for 10min, and then the supernatant was taken 3cm below the liquid surface with a pipette. The COD, turbidity and transmittance were measured, and the data before treatment were compared and analyzed. The test results are shown in Table 1.

[0059] Table 1 Performance test results

[0060]

[0061]

[0062] Data analysis shows that the water purifier of the present invention has an excellent purification effect on the Yellow River water and exhibits a better purification effect than the commercially available polyaluminum chloride water purifier.

[0063] As can be seen from Example 2 and Comparative Examples 4 and 5 in Table 1, the present invention involves ferroferric oxide in the polymerization process of aluminum chloride, so that ferroferric oxide can form a molecular-level composite with polyaluminum chloride, with high bonding strength, not easy to dissociate, and can form multi-nuclear active sites to enhance its adsorption capacity; and the in-situ composite can make ferroferric oxide uniformly dispersed in the PAC skeleton structure, and the polyamined ferroferric oxide can play a certain chemical bridging role, further enhancing the bonding strength between ferroferric oxide and aluminum hydrolyzate, forming a more stable hybrid structure, so that it can produce a more stable "bridging" effect in the sedimentation flocculation type, and then the surrounding particles can be captured during the formation of the precipitate, prompting them to settle together.

[0064] As can be seen from Example 2 and Comparative Examples 1, 2, and 3 in Table 1, the present invention polyaminates ferroferric oxide using tetraethylenepentamine and double-terminated amino polyethylene glycol. On the one hand, the presence of more amino groups can further enhance the electrostatic effect, thereby further enhancing its flocculation effect. On the other hand, it provides more active coordination sites, which can form a tighter and more extensive dendritic cross-linked network with the Al-OH of PAC, thereby enhancing the adsorption of free impurities and particles in water and enhancing the "bridging" and "netting" effects of the flocculant. At the same time, the ether chain of the double-terminated amino polyethylene glycol promotes the polymerization of polyaluminum chloride on the surface of ferroferric oxide. On the other hand, the long-chain ether bond can be stretched during the flocculation process, thereby promoting flocculation efficiency.

[0065] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A method for preparing a polyaluminium chloride water purifier, characterized in that: The following steps are involved: S1: Mix ferrosoferric oxide, ethanol aqueous solution, and ammonia water, stir, then add tetraethyl orthosilicate and 3-aminopropyltriethoxysilane, stir for 6 hours, and purify the product to obtain amino ferrosoferric oxide; S2: Mix aminated ferrosoferric oxide and methanol, add methyl acrylate, stir for 24 hours, then add tetraethylene pentamine and double-terminated amino polyethylene glycol, heat to 50-55°C, stir and react for 12 hours to obtain polyaminated ferrosoferric oxide; S3: Mix polyamine ferrosoferric oxide, deionized water, and aluminum chloride, stir, adjust the pH to 3-4, heat to 60-65°C, hydrolyze for 1-2 hours, then heat to 80-85°C, polymerize for 1-2 hours, cool to room temperature, age for 24 hours, centrifuge, and dry to obtain a polyaluminum chloride water purifier; The ratio of the amount of ferrosilicate, ethanol aqueous solution, ammonia water, tetraethyl orthosilicate, and 3-aminopropyltriethoxysilane used in step S1 is 5-6g:500-600g:10-12g:12-14g:2-3g; In step S2, the ratio of the amount of amination ferrosoferric oxide, methanol, methyl acrylate, tetraethylene pentamine, and double-terminated amino polyethylene glycol is 5-6 g: 500-550 g: 0.5-0-6 g: 1.5-1.8 g: 1-1.5 g; In step S3, the usage ratio of polyamine ferrosoferric oxide, deionized water, and aluminum chloride is 4-5g:500-600g:20-25g.

2. The preparation method of polyaluminium chloride water purifier according to claim 1, wherein The average particle size of the ferrosoferric oxide in step S1 is 300-400 nm.

3. The preparation method of polyaluminium chloride water purifier according to claim 1, wherein The concentration of the ethanol aqueous solution in step S1 is 80wt%-85wt%.

4. The preparation method of polyaluminium chloride water purifier according to claim 1, wherein The concentration of the ammonia water in step S1 is 28 wt%-30 wt%.

5. The preparation method of polyaluminium chloride water purifier according to claim 1, wherein The weight average molecular weight of the double-terminated amino polyethylene glycol in step S2 is 1000.

6. The preparation method of polyaluminium chloride water purifier according to claim 1, wherein The pH in step S3 is adjusted using hydrochloric acid.

7. A polyaluminium chloride water purifier, characterized in that, The polyaluminium chloride water purifier is prepared by the preparation method of the polyaluminium chloride water purifier according to any one of claims 1 to 6.

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