Preparation method and application of mine water flocculation agent with adsorption function

Abstract

The invention relates to a preparation method and application of a mine water flocculation agent with an adsorption function. The mine water flocculation agent is prepared from the following raw materials: a mineral material, chitosan, water, silicate, acid, aluminum chloride salt, ferric chloride salt and polyacrylamide. The preparation method comprises the following steps: carrying out heat treatment on a mineral material, then adding water and chitosan, then adding silicate, reacting to generate polysilicic acid, grafting the polysilicic acid on chitosan macromolecules, then adding aluminum chloride salt and ferric chloride salt, reacting, finally adding polyacrylamide, and aging to obtain the composite material. The mine water flocculating agent provided by the invention can synchronously remove suspended matters, fluorides and COD (Chemical Oxygen Demand), and has the advantages of low dosage, short reaction time and high settling speed.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a mine water flocculating agent with adsorption function, belonging to the technical field of mine water treatment. Background Art

[0002] As a byproduct resource of coal mining, mine water is a good choice as a reserve water source. Conventional mine water treatment mainly separates suspended matter, colloids, etc. in mine water. Generally, it can meet the discharge standard after adding PAC and PAM coagulation and sedimentation treatment, but the dosage of the agent is large and the flocs formed settle slowly. With the continuous improvement of the requirements for the reuse and recycling of water resources, pollutants such as fluoride and COD in mine water have become necessary conditions for treatment. However, conventional coagulation and sedimentation treatment with polyaluminium chloride (PAC) and polyacrylamide (PAM) cannot remove fluoride and soluble COD. If fluoride and soluble COD are to be removed, other treatment measures need to be added, which leads to a sharp increase in the initial investment and system area of ​​mine water treatment. In addition, compared with traditional flocculation and sedimentation agents, the dosage is large, the reaction cycle is long, the treatment effect is poor, and the reaction equipment is large, which will also affect the subsequent treatment system. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In order to solve the above problems in the prior art, the present invention provides a method for preparing a mine water flocculant with adsorption function, which has the effect of simultaneously removing suspended matter, fluoride and COD, and has low usage, short reaction time and fast sedimentation rate, and can effectively solve the problems existing in the above background technology.

[0005] (II) Technical solution

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] The invention discloses a mine water flocculating agent with adsorption function, which is made of raw materials including mineral materials, chitosan, water, silicate, acid, aluminum chloride salt, ferric chloride salt and polyacrylamide.

[0008] The mine water flocculating agent as described above, calculated by mass, comprises 1 to 3 parts of mineral material, 3 to 4 parts of chitosan, 5 to 10 parts of water, 8 to 18 parts of silicate, 5 to 10 parts of aluminum chloride, 5 to 10 parts of ferric chloride, and polyacrylamide accounts for 0.03 to 0.4% of the total mass of the aforementioned raw materials.

[0009] As described above, the mine water flocculating agent is preferably a mineral material of zeolite, porous clay or hydroxyapatite with a particle size of 80 to 120 microns; the silicate is sodium silicate or potassium silicate, which is first prepared into an aqueous solution with a mass concentration of 20 to 40% when used.

[0010] As described above, in the mine water flocculating agent, preferably, the aluminum chloride salt is polyaluminum chloride, and the ferric chloride salt is polyferric chloride.

[0011] The method for preparing the mine water flocculating agent as described above comprises the following steps:

[0012] S1. Heat treating the mineral material;

[0013] S2, adding water and chitosan, mixing and then performing ultrasonic treatment to evenly disperse the mineral material and chitosan;

[0014] S3, adding silicate solution to the mixture after ultrasonication, adjusting the pH value to acidic with acid after stirring, adding aluminum chloride salt and iron chloride salt, and continuing stirring to react;

[0015] S4, adding polyacrylamide to the mixture after the stirring reaction in S3, stirring and aging in a constant temperature box;

[0016] S5. After aging, take out, filter, air-dry and grind to obtain a mine water flocculating agent.

[0017] In the preparation method as described above, preferably, in step S1, the heating treatment is to keep the temperature at 300° C. for 20 to 45 minutes.

[0018] In the preparation method as described above, preferably, in step S2, the stirring time during the mixing is 10 to 20 minutes; and the ultrasonic treatment condition is 28 to 40 kHz for 20 to 60 minutes.

[0019] In the preparation method as described above, preferably, in step S3, the acid is acetic acid or hydrochloric acid, and the pH value is adjusted to 2.0-4.0.

[0020] In the preparation method as described above, preferably, in step S3, the stirring reaction time is 15 to 45 minutes, and the stirring rate is 50 to 250 rpm.

[0021] In the preparation method as described above, preferably, in step S4, the stirring time is 5 to 15 minutes; and the aging condition is aging in a constant temperature box at 20° C. for 20 to 28 hours.

[0022] The use of the mine water flocculant as described above or the mine water flocculant obtained by the preparation method in removing fluoride and soluble COD from mine water. When the mine water flocculant is used to remove fluoride and soluble COD from mine water, the amount of the flocculant added is related to the concentration of fluoride and soluble COD in the raw water, and the specific amount can be determined by a small test.

[0023] (III) Beneficial effects

[0024] The beneficial effects of the present invention are:

[0025] The preparation method of the mine water flocculant with adsorption function provided by the present invention comprises the following steps: firstly heat-treating the mineral material; opening the internal pores thereof, then adding water and chitosan, allowing the chitosan to penetrate into the pores of the mineral material, and allowing the larger pores to become denser micropores with adsorption capacity for ions, so that the mineral material has a stronger adsorption and removal capacity for fluoride and COD in the mine water; then adding silicate, generating polysilicic acid through reaction, grafting on the chitosan macromolecules, forming a macromolecular network structure, and enhancing the net capture effect of the flocculant; then adding aluminum chloride salt and ferric chloride salt, allowing the mineral material to load aluminum chloride salt and ferric chloride salt in combination with the mineral metal elements rich in zeolite itself, so that the flocculant has a stronger cationic effect, enhancing the electrostatic attraction and van der Waals force of the flocculant on suspended matter, and enhancing the adsorption effect; finally, further compounding with polyacrylamide is used to prepare the flocculant with adsorption capacity with the mineral material as the core.

[0026] The mine water flocculating agent provided by the invention can remove suspended matter, fluoride and COD simultaneously, and has the advantages of low dosage, short reaction time and fast sedimentation speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flow chart for preparing the mine water flocculating agent provided by the present invention;

[0028] Figure 2 This is a diagram of the structural changes in the preparation process of the mine water flocculating agent provided by the present invention. DETAILED DESCRIPTION

[0029] The principle of the invention is that the mineral material is first subjected to heat treatment to fully release the internal pores; then chitosan is used as a cross-linking agent to penetrate into the zeolite pores, so that the larger pores are transformed into denser micropores with adsorption capacity for ions, so that the pores have a stronger adsorption and removal effect on fluoride and COD in mine water; silicate generates polysilicic acid through reaction, which is grafted on the chitosan macromolecule to form a macromolecular network structure, thereby enhancing the net capture effect of the flocculant; then aluminum chloride salt and ferric chloride salt are loaded to combine with the mineral metal elements rich in the zeolite itself, so that the flocculant has a stronger cationic effect, and the flocculant has enhanced electrostatic attraction and van der Waals force on suspended matter; finally, a flocculant with adsorption capacity with the mineral material as the core is prepared through further compounding with polyacrylamide.

[0030] Specifically, after the heat treatment of mineral materials such as zeolite, porous clay or hydroxyapatite, a small amount of volatile substances mixed in the material can be removed, and the substances adsorbed in the pores of the material can be removed, and the pores of the material can be fully opened, which is beneficial to the adsorption and removal effect of COD and fluoride ions in the mine water during the mine water treatment process. The mineral material serves as the crystal nucleus of the flocculant of the present invention and the basis of the subsequent grafting reaction. At the same time, the specific gravity of the final flocculant can be adjusted, which is beneficial to the rapid sedimentation during the mine water treatment process; chitosan is an alkaline polysaccharide with more functional groups and free amino groups in the molecular chain. In the preparation process of the flocculant of the present invention, the chitosan is more evenly attached to the mineral material through ultrasonic treatment. The surface and pores of the material form a preparation process product with a mineral material as the core and chitosan as the primary shell with positive charge; polysilicic acid is generated in the silicate reaction process, and the dispersed preparation process products with a mineral material as the core and chitosan as the primary shell with positive charge are connected to increase the degree of polymerization of the molecules, and form a long-chain flocculant with multiple mineral material particles and polysilicic acid as a connector; the iron ions and aluminum ions in the subsequent ferric chloride and aluminum chloride are combined with the long-chain flocculants through coordination bonds, thereby enhancing the positive charge of the flocculant; finally, polyacrylamide bridges the long-chain flocculants through hydrogen bond adsorption and electrostatic attraction to form larger flocs, and finally the organic-inorganic composite mine water flocculant with adsorption function described in the present invention is prepared.

[0031] Furthermore, the preparation method of the mine water flocculating agent with adsorption function of the present invention is as follows: Figure 1 As shown, the steps include: S1, heating the mineral material;

[0032] S2, adding water and chitosan to react, and performing ultrasonic treatment after mixing to uniformly disperse the mineral material and chitosan;

[0033] S3, adding silicate solution to the mixture after ultrasonication, adjusting the pH value to acidic with acid after stirring, adding aluminum chloride salt and iron chloride salt, and continuing stirring to react;

[0034] S4, adding polyacrylamide to the mixture after the stirring reaction in S3 to lengthen the connecting chain, stirring and aging in a constant temperature box to perform bridging net capture;

[0035] S5. After aging, take out, filter, air-dry and grind to obtain a mine water flocculation agent. The structural changes of the substances during the preparation process can be seen in Figure 2 shown.

[0036] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods.

[0037] Example 1

[0038] Place 100g of zeolite in a muffle furnace, adjust the temperature to rise by 50℃ every 10min until 300℃ and keep it at 300℃ for 30min. After the heat-treated zeolite is naturally cooled, add 500mL of pure water and 350g of chitosan in turn, and stir thoroughly for 15min. Then treat the mixture under 35KHz ultrasound for 40min. Add 3000mL of silicate solution with a mass concentration of 30% (that is, the silicate is sodium silicate with a mass of 900g), then use acetic acid solution to adjust the pH to 3.0, and add 500g of polyferric chloride and polyaluminum chloride respectively, and stir thoroughly for 30min. Finally, add 3g of polyacrylamide, stir for 10min, and place it in a 20℃ constant temperature box for aging for 24h. After aging, take out the mine water flocculation agent with adsorption function obtained by filtering, air-drying and grinding.

[0039] Example 2

[0040] Place 100g of zeolite in a muffle furnace, adjust the temperature to 100℃ to 300℃ every 10min, and continue heating at 300℃ for 30min. After the heat-treated zeolite is naturally cooled, add 800mL of pure water and 300g of chitosan in turn, and stir thoroughly for 15min. Then treat the mixture under 30KHz ultrasound for 30min. Add 4000mL of 30% mass concentration of sodium silicate solution, then use acetic acid solution to adjust the pH to 3.0, and add 1000g of polyferric chloride and polyaluminum chloride respectively, stir thoroughly for 30min. Finally, add 10g of polyacrylamide, stir for 10min, and place in a 20℃ constant temperature box for aging for 24h. After aging, take out the filter, air-dry and grind to obtain a mine water flocculation agent with adsorption function.

[0041] Example 3

[0042] Place 50g of zeolite in a muffle furnace, adjust the temperature to 100℃ to 300℃ every 10min, and continue heating for 30min. After the heat-treated zeolite is naturally cooled, add 300mL of pure water and 300g of chitosan in turn, and stir thoroughly for 15min. Then treat the mixture under 40KHz ultrasound for 30min. Add 2000mL of 30% mass concentration potassium silicate solution, then use acetic acid solution to adjust the pH to 3.0, and add 400g of polyferric chloride and polyaluminum chloride respectively, and stir thoroughly for 30min. Finally, add 2g of polyacrylamide, stir for 10min, and place in a 20℃ constant temperature box for aging for 24h. After aging, take out the filter, air-dry and grind to obtain a mine water flocculation agent with adsorption function.

[0043] Example 4

[0044] The mine water of a coal mine in Ordos contains suspended matter 1200 mg / L, soluble COD 35 mg / L, and fluoride 2.0 mg / L. Natural zeolite, polyaluminium chloride (PAC), polyferric sulfate (PFS), the flocculant prepared by the present invention, and polyacrylamide (PAM) are added respectively, and the water quality of the supernatant after the reaction is completed is detected. The treatment effects of the flocculant of the present invention and PAC are compared, and the addition conditions are as follows:

[0045] Condition 1: Add PAC 150mg / L, no PAM

[0046] Condition 2: Add PAC 150mg / L, add PAM 1.5mg / L

[0047] Condition 3: Add PFS 150mg / L, add PAM 1.5mg / L

[0048] Condition 4: 100 mg / L of the flocculants of Examples 1 to 3 of the present invention and 1.0 mg / L of PAM were added respectively.

[0049] Condition 5: Add 20 mg / L natural zeolite, 130 mg / L PAC, and 1.5 mg / L PAM.

[0050] Take the above-mentioned mine water and add the corresponding reagents according to the above conditions, stir the reaction and precipitate for 30 minutes, then take the supernatant, use the national standard method to detect the suspended matter (GB / T 11901-1989) and COD (potassium dichromate method) in the supernatant, and use a fluoride detector to determine the fluoride concentration. The treatment effects of the above-mentioned different conditions are judged by comparing the three types of water quality indicators in the "Surface Water Environmental Quality Standard" (GB3838-2022). The comparison of the water quality indicators after treatment is shown in Table 1 below.

[0051] Table 1

[0052]

[0053]

[0054] It can be seen from the results that after treatment with the flocculant prepared by Examples 1-3 of the present invention, the suspended matter, COD and fluoride indicators of the mine water meet the requirements of the three water quality indicators in the "Surface Water Environmental Quality Standard" (GB3838-2022), and the relevant indicators under other conditions do not meet the requirements of the three water quality indicators in the "Surface Water Environmental Quality Standard" (GB3838-2022), indicating that the flocculant prepared by the present invention has a good removal effect on suspended matter, COD and fluoride in mine water, and the effect is significant. This is because when the mine water is added with the flocculant with adsorption capacity provided by the present invention, its cationic properties will attract the fluoride in the mine water through hydrogen bonds or electrostatic attraction, and then be adsorbed by the micropores of the mineral material, and the micropores will simultaneously adsorb the soluble COD in the mine water; the mesh structure of the flocculant will capture the suspended matter and colloid in the mine water to form a flocculent with the mineral material as the core. Due to the large specific gravity of the mineral material, the flocculent will settle quickly and separate from the water.

[0055] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any person skilled in the art can use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A mine water flocculating agent with adsorption function, characterized in that: The invention is prepared from raw materials including mineral materials, chitosan, water, silicate, acid, aluminum chloride salt, iron chloride salt and polyacrylamide.

2. The mine water flocculating agent according to claim 1, characterized in that: In terms of mass, the raw materials are 1-3 parts of mineral materials, 3-4 parts of chitosan, 5-10 parts of water, 8-18 parts of silicate, 5-10 parts of aluminum chloride salt, 5-10 parts of ferric chloride salt, and polyacrylamide accounts for 0.03-0.4% of the total mass of the above raw materials.

3. The mine water flocculating agent according to claim 1, characterized in that: The mineral material is zeolite, porous clay or hydroxyapatite, and its particle size is 80-120 microns; the silicate is sodium silicate or potassium silicate, which is first configured into an aqueous solution with a mass concentration of 20-40% when used.

4. The mine water flocculating agent according to claim 1, characterized in that: The aluminum chloride salt is polyaluminum chloride, and the ferric chloride salt is polyferric chloride.

5. The method for preparing a mine water flocculating agent according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1. Heat treating the mineral material; S2, adding water and chitosan, mixing and then performing ultrasonic treatment to evenly disperse the mineral material and chitosan; S3, adding silicate solution to the mixture after ultrasonication, adjusting the pH value to acidic with acid after stirring, adding aluminum chloride salt and iron chloride salt, and continuing stirring to react; S4, adding polyacrylamide to the mixture after the stirring reaction in S3, stirring and aging in a constant temperature box; S5. After aging, take out, filter, air-dry and grind to obtain a mine water flocculating agent.

6. The preparation method according to claim 5, characterized in that: In step S1, the heating treatment is performed at 300°C for 20 to 45 minutes.

7. The preparation method according to claim 5, characterized in that: In step S2, the stirring time during the mixing is 10 to 20 minutes; the ultrasonic treatment condition is 28 to 40 KHz for 20 to 60 minutes.

8. The preparation method according to claim 5, characterized in that: In step S3, the acid is acetic acid or hydrochloric acid, and the pH value is adjusted to 2.0-4.0; the stirring reaction time is 15-45 minutes, and the stirring rate is 50-250 rpm.

9. The preparation method according to claim 5, characterized in that: In step S4, the stirring time is 5 to 15 minutes; the aging condition is aging in a constant temperature box at 20° C. for 20 to 28 hours.

10. Use of the mine water flocculating agent as claimed in any one of claims 1 to 4 or the mine water flocculating agent obtained by the preparation method as claimed in any one of claims 5 to 9 in removing fluoride and soluble COD from mine water.

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