A kind of fly ash nano magnetic bead flocculant and preparation method thereof

Abstract

The invention discloses a fly ash nano magnetic bead flocculant, which is composed of the following raw materials in parts by weight: 1-30 parts of fly ash, 0.5-1 parts of nano silicon dioxide, 2-5 parts of dispersant, 1-2.5 parts of tetramethylpropylenediamine, 0.1-0.5 parts of polyacrylamide, and 1-5 parts of surfactant. At the same time, the invention also discloses a preparation method of the flocculant. The flocculant has high physical adsorption performance, has good chelation effect on metal ions, is not easy to deposit in water, can fully react with sewage, and has good adsorption and flocculation effect on suspended matter in sewage sludge.

Description

Technical Field

[0001] The invention belongs to an oilfield sewage treatment flocculant, in particular to a fly ash nano magnetic bead flocculant and a preparation method thereof. Background Art

[0002] Under the background of rapid development of oilfield development industry, the amount of oilfield wastewater is also increasing sharply. The water quality of wastewater treatment is a necessary condition to ensure the smooth development of oil and gas fields. If the water quality of water injected into the injection well does not meet the standard, the oil and gas seepage channel of the underground reservoir will be easily blocked, resulting in a decrease in oil and gas production. In addition, the pressure of water injection becomes larger, resulting in an increase in the energy consumption of water injection. Therefore, it is necessary to strengthen the attention and attention to the issue of oilfield wastewater treatment.

[0003] Oilfield wastewater treatment generally undergoes preliminary treatment by sediment filtration, and then secondary treatment by a water purifier to condense the small particle molecules in the wastewater into a large molecular cluster structure. After a period of standing and filtering, the impurity particles are removed from the wastewater to meet the discharge standards. The flocculation and sedimentation process is an indispensable and important operating unit in various water treatment and purification processes, and it is also the most widely used and most common unit treatment process. By adding flocculants to the aqueous solution, its function is to soften the water quality, reduce the quality of the foam, decolorize, and remove the suspended sol particles in the water. The widely used flocculants at present are mainly aluminum flocculants (such as aluminum chloride, aluminum sulfate, polyaluminum chloride, polyaluminum sulfate, etc.) and iron flocculants (such as ferric chloride, ferric sulfate, polyferric chloride, polyferric sulfate, etc.). Because aluminum flocculants are used in sewage treatment in a small pH range, large dosage, slow sedimentation of the flocs produced, and Al 3+ The residue in the water body will cause harm to the human body. Iron-based flocculants will cause the water body to turn yellow after use, and they are highly corrosive. These flocculants all use their own gravity to achieve sedimentation, so they all have problems such as insufficient floc sedimentation power, unstable flocculation effect, and high cost.

[0004] Magnetic flocculation technology is a water treatment technology that uses flocculation technology and magnetic separation technology at the same time. It has the characteristics of simple process, high efficiency and no secondary pollution. In recent years, magnetic flocculation technology has been widely studied and applied in sewage treatment. For example, Chinese patent CN1864211A discloses a method of dispersing magnetic powder in a natural organic flocculant chitosan solution to prepare a magnetic chitosan solution, and using the adsorption bridging and electrical neutralization of chitosan and the magnetic responsiveness of magnetic powder to remove algal bloom pollution in water bodies. Chinese patent CN10665280A uses recycled iron-containing flocs, which are oxidized and treated with acid to obtain a magnetic flocculant, which can be used to treat iron-containing wastewater and has the advantages of low floc moisture content. CN101054222 uses the reaction product of ultrapure magnetite powder, fly ash, and concentrated hydrochloric acid mixed with polyaluminum ferric chloride to prepare a magnetic composite flocculant, which achieves efficient magnetic flocculation separation of algal blooms in water. Chinese patent CN102627342A discloses a magnetic powder flocculant and its application method, wherein the magnetic powder used is spinel magnetic powder represented by MFe2O4. Chinese patent CN101423273A discloses a nano-Al 13 A composite paramagnetic nano-flocculant composed of SiO2 / γ-Fe3O4-SiO2 and a magnetic carrier and a preparation method thereof. In the prior art, although magnetic flocculation technology realizes the composite use of flocculants and magnetic seeds, the preparation process of the flocculant is still complicated, the cost is high, the degradation rate of the flocculant is slow, and the flocculation effect is difficult to guarantee. Summary of the invention

[0005] In view of the defects of the prior art, the present invention provides a fly ash nano magnetic bead flocculant and a preparation method thereof. The flocculant has high physical adsorption performance and good chelating effect on metal ions.

[0006] A fly ash nano magnetic bead flocculant is composed of the following raw materials in parts by weight: 1-30 parts of fly ash, 0.5-1 part of nano silicon dioxide, 2-5 parts of dispersant, 1-2.5 parts of tetramethylpropylenediamine, 0.1-0.5 parts of polyacrylamide and 1-5 parts of surfactant.

[0007] Preferably, the surfactant is at least one of oleic acid, OP-10 and Span60.

[0008] Preferably, the dispersant is ethanol or acetone.

[0009] Preferably, the molecular weight of the polyacrylamide is 8 million, and it is at least one of cationic polyacrylamide, anionic polyacrylamide, nonionic polyacrylamide, and zwitterionic polyacrylamide.

[0010] The preparation method of the fly ash nano magnetic bead flocculant comprises the following steps:

[0011] (1) at room temperature, mixing fly ash, nano-silicon dioxide, a dispersant and tetramethylpropylenediamine to obtain a mixed solution;

[0012] (2) heating the mixed solution to 40-50° C., adding a surfactant, and stirring to obtain a fly ash nano-magnetic bead suspension;

[0013] (3) adding polyacrylamide to the fly ash nano magnetic bead suspension, stirring until swelling, and then standing for aging to obtain a fly ash nano magnetic bead / polyacrylamide gel;

[0014] (4) Drying the fly ash nano magnetic beads / polyacrylamide gel and then shearing and crushing it to obtain the fly ash nano magnetic beads flocculant.

[0015] Preferably, the stirring is carried out at a rotation speed of 200-300 rpm for 2-2.5 hours.

[0016] Preferably, the aging time is 2-3 hours.

[0017] Preferably, the drying temperature is 75-85°C.

[0018] Fly ash is rich in aluminum, copper, iron, zinc and other elements, which can not only absorb heavy metals in wastewater but also be grafted and cross-linked with silicon dioxide, starch and the like. The fly ash nano magnetic bead flocculant prepared by the present invention can utilize magnetic field to separate precipitation during the precipitation separation process, thereby improving the efficiency of wastewater treatment. The fly ash is activated by dispersant and tetramethylpropylenediamine, thereby expanding the surface pore size of the fly ash, increasing its physical adsorption performance, and improving its chemical bonding performance, so that the prepared flocculant has stronger chelating performance for metal ions, the formed flocs are more compact, and the flocculation sedimentation rate is increased, thereby improving the flocculation efficiency.

[0019] The hydrogen bonds of nano-silicon dioxide have a strong adsorption effect on pollutants in wastewater, and at the same time have a certain complexing effect on metal ions. The present invention uses nano-silicon dioxide and fly ash as carriers, utilizes the hydrogen bonds of nano-silicon dioxide to cross-link fly ash and polyacrylamide, and the nano-silicon dioxide and polyacrylamide have more hydroxyl groups on the surfaces. The fly ash nano-magnetic bead flocculant finally prepared has better flocculation efficiency.

[0020] The advantages of the present invention are:

[0021] (1) The present invention uses fly ash and nano-silicon dioxide as carriers and utilizes hydrated modified fly ash to increase the surface pore size of fly ash and improve its physical adsorption performance. The prepared flocculant has a stronger chelating effect on metal ions and has a high flocculation efficiency.

[0022] (2) Achieve uniform compounding of fly ash nano-magnetic beads and flocculants, and improve the magnetic properties and structural stability of magnetic flocculants;

[0023] (3) Fly ash nano magnetic bead flocculants are small in size and are not easy to settle in water. They can fully react with sewage and have good adsorption and flocculation effects on suspended matter in sewage sludge;

[0024] (4) The use of industrial waste fly ash as material improves the recycling of materials, reduces production costs, eliminates environmental pollution, and provides a good demonstration for the implementation of the sustainable development strategy. Implementation

[0025] Example 1

[0026] 1. A fly ash nano magnetic bead flocculant, composed of the following raw materials in parts by weight: 1 part of fly ash, 0.5 parts of nano silicon dioxide, 2 parts of dispersant, 1 part of tetramethylpropylenediamine, 0.1 parts of polyacrylamide, and 1 part of surfactant;

[0027] Wherein, the surfactant is a mixture of equal volumes of oleic acid and Span60;

[0028] The dispersant is ethanol;

[0029] The molecular weight of the polyacrylamide is 8 million, and it is a cationic polyacrylamide.

[0030] 2. The preparation method of the fly ash nano magnetic bead flocculant comprises the following steps:

[0031] (1) at room temperature, mixing fly ash, nano-silicon dioxide, a dispersant and tetramethylpropylenediamine to obtain a mixed solution;

[0032] (2) heating the mixed solution to 40° C., adding a surfactant, and stirring and mixing to obtain a fly ash nano-magnetic bead suspension;

[0033] (3) adding polyacrylamide to the fly ash nano magnetic bead suspension, stirring at a speed of 200 rpm for 2 hours to allow swelling, and then standing and aging for 2 hours to obtain a fly ash nano magnetic bead / polyacrylamide gel;

[0034] (4) Drying the fly ash nano magnetic beads / polyacrylamide gel at 80° C. to a constant weight, and then shearing and crushing it to obtain the fly ash nano magnetic beads flocculant.

[0035] Example 2

[0036] 1. A fly ash nano magnetic bead flocculant, composed of the following raw materials in parts by weight: 30 parts of fly ash, 1 part of nano silicon dioxide, 5 parts of dispersant, 2.5 parts of tetramethylpropylenediamine, 0.5 parts of polyacrylamide, and 5 parts of surfactant;

[0037] Wherein, the surfactant is a mixture of equal volumes of oleic acid and Span60;

[0038] The dispersant is ethanol;

[0039] The molecular weight of the polyacrylamide is 8 million, and it is an anionic polyacrylamide.

[0040] 2. The preparation method of the fly ash nano magnetic bead flocculant comprises the following steps:

[0041] (1) at room temperature, mixing fly ash, nano-silicon dioxide, a dispersant and tetramethylpropylenediamine to obtain a mixed solution;

[0042] (2) heating the mixed solution to 50° C., adding a surfactant, and stirring and mixing to obtain a fly ash nano-magnetic bead suspension;

[0043] (3) adding polyacrylamide to the fly ash nano magnetic bead suspension, stirring at 300 rpm for 2 hours to allow swelling, and then standing and aging for 3 hours to obtain a fly ash nano magnetic bead / polyacrylamide gel;

[0044] (4) Drying the fly ash nano magnetic beads / polyacrylamide gel at 75° C. to a constant weight, and then shearing and crushing it to obtain the fly ash nano magnetic beads flocculant.

[0045] Example 3

[0046] 1. A fly ash nano magnetic bead flocculant, composed of the following raw materials in parts by weight: 15 parts of fly ash, 0.5 parts of nano silicon dioxide, 5 parts of dispersant, 2.5 parts of tetramethylpropylenediamine, 0.25 parts of polyacrylamide, and 3 parts of surfactant;

[0047] Wherein, the surfactant is a mixture of equal volumes of oleic acid and Span60;

[0048] The dispersant is ethanol;

[0049] The molecular weight of the polyacrylamide is 8 million, and it is a non-ionic polyacrylamide.

[0050] 2. The preparation method of the fly ash nano magnetic bead flocculant comprises the following steps:

[0051] (1) at room temperature, mixing fly ash, nano-silicon dioxide, a dispersant and tetramethylpropylenediamine to obtain a mixed solution;

[0052] (2) heating the mixed solution to 40° C., adding a surfactant, and stirring and mixing to obtain a fly ash nano-magnetic bead suspension;

[0053] (3) adding polyacrylamide to the fly ash nano magnetic bead suspension, stirring at a speed of 200 rpm for 2.5 hours to allow swelling, and then standing and aging for 2 hours to obtain a fly ash nano magnetic bead / polyacrylamide gel;

[0054] (4) Drying the fly ash nano magnetic beads / polyacrylamide gel at 85° C. to a constant weight, and then shearing and crushing it to obtain the fly ash nano magnetic beads flocculant.

[0055] The fly ash nano magnetic bead flocculant provided by the present invention is used for oilfield wastewater treatment. The oilfield produced wastewater has the following characteristics: dark color, heavy metal content of 100 mg / L, COD content of 30000 mg / L, large suspended matter median particle size of 25.86 um; high bacterial content, mostly sulfate-reducing bacteria and saprophytic bacteria, and contains a small amount of sulfide. The treatment results are shown in Table 1. At the same time, polyaluminium chloride flocculant is used as a comparative example. The flocculant addition amount is 120 mg / L.

[0056] Table 1 Wastewater treatment

[0057]

[0058] Among them, - means that it cannot be detected.

[0059] When polyaluminium chloride is used as a flocculant for treatment, it cannot settle, resulting in the inability to remove heavy metals.

Claims

1. A fly ash nano magnetic bead flocculant, characterized in that: The invention is composed of the following raw materials in parts by weight: 1-30 parts of fly ash, 0.5-1 parts of nano silicon dioxide, 2-5 parts of dispersant, 1-2.5 parts of tetramethylpropylenediamine, 0.1-0.5 parts of polyacrylamide and 1-5 parts of surfactant.

2. The fly ash nano magnetic bead flocculant according to claim 1, characterized in that: The surfactant is at least one of oleic acid, OP-10 and Span60.

3. The fly ash nano magnetic bead flocculant according to claim 2, characterized in that: The dispersant is ethanol or acetone.

4. The fly ash nano magnetic bead flocculant according to claim 3, characterized in that: The molecular weight of the polyacrylamide is 8 million, and the polyacrylamide is at least one of cationic polyacrylamide, anionic polyacrylamide, nonionic polyacrylamide, and zwitterionic polyacrylamide.

5. The method for preparing the fly ash nano magnetic bead flocculant according to claim 1, characterized in that: The following steps are involved: (1) at room temperature, mixing fly ash, nano-silicon dioxide, a dispersant and tetramethylpropylenediamine to obtain a mixed solution; (2) heating the mixed solution to 40-50° C., adding a surfactant, and stirring to obtain a fly ash nano-magnetic bead suspension; (3) adding polyacrylamide to the fly ash nano magnetic bead suspension, stirring until swelling, and then standing for aging to obtain a fly ash nano magnetic bead / polyacrylamide gel; (4) Drying the fly ash nano magnetic beads / polyacrylamide gel and then shearing and crushing it to obtain the fly ash nano magnetic beads flocculant.

6. The method for preparing the fly ash nano magnetic bead flocculant according to claim 5, characterized in that: The stirring in step (3) is performed at a rotation speed of 200-300 rpm for 2-2.5 hours.

7. The method for preparing the fly ash nano magnetic bead flocculant according to claim 5, characterized in that: The aging time is 2-3h.

8. The method for preparing the fly ash nano magnetic bead flocculant according to claim 5, characterized in that: The drying temperature is 75-85°C.

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