A magnetic condensation nucleus for magnetic nucleus flocculant water separation process

Abstract

The invention discloses a magnetic condensation nucleus for a magnetic core flocculent water separation treatment process, the magnetic condensation nucleus comprises the following raw materials: ferroferric oxide powder and PTFE emulsion, and the preparation method thereof comprises the following steps: step S1: washing the ferroferric oxide powder with deionized water; step S2: dehydrating the washed ferroferric oxide powder, and then uniformly mixing it with the PTFE emulsion for impregnation and coating treatment, granulating the mixed slurry by high-temperature rotary spraying, and further drying after granulation; step S3: plasma-treating the impregnated and dried powder again, treating the powder with plasma gas after excitation, so as to activate and modify the film surface of the film body. The invention selects to coat the surface of the ferroferric oxide powder particles first, covering a layer of corrosion-resistant and wear-resistant organic film, and then modifying the coating on the surface of the particles, so as to achieve the purpose of changing the surface properties while retaining the magnetism.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic flocculation water treatment technology, in particular to a magnetic condensation core used in a magnetic core flocculation water treatment technology. Background Art

[0002] The magnetic core flocculation sedimentation technology is an improvement on the traditional flocculation sedimentation process. That is, magnetic cores (magnetic seeds) are added in the coagulation sedimentation process to make them coagulate with the pollutant flocs to strengthen the coagulation and flocculation, so that the average density of the generated flocs is higher, the volume is larger, and the sedimentation is better, thereby achieving the purpose of high-speed sedimentation. The floc group sedimentation rate is as high as 30-40m / h, and the surface load can reach 30m³ / ㎡h-40m³ / ㎡h; at the same time, the magnetic core can be recycled through the magnetic drum. Therefore, compared with the traditional flocculation sedimentation process, it has many advantages such as fast speed, high efficiency, small footprint, and small investment. Precisely because of its short residence time, the probability of flocs undergoing a reverse dissolution process is extremely small, and the addition of magnetic powder and flocculants has a good adsorption effect on a variety of tiny particles including bacteria, viruses, and oil. Therefore, it has been widely used in various fields, including: upgrading and transformation of sewage treatment plants; deep phosphorus removal and removal of suspended solids; treatment of black and odorous water in rivers; heavy metal wastewater treatment; oily wastewater treatment; phosphorus removal, algae removal, and softening in the tap water field, etc.

[0003] The existing magnetic cores (magnetic seeds) are mostly made of 200-300 mesh ferroferric oxide powder. Due to the poor hydrophilicity of the particle surface and its surface charge characteristics, it cannot effectively combine with the flocs, resulting in the measured sedimentation rate of the flocs containing magnetic seeds often being lower than 30m / h. Therefore, the surface load is often selected as 20m³ / ㎡h-25m³ / ㎡h during design. Even so, in actual use, the magnetic core and flocs will still run away before they can settle because the design flow rate is too high, which is often called "running flocs" or "running magnets", which seriously limits the promotion, use and development of magnetic core flocculation and sedimentation technology. Summary of the invention

[0004] The purpose of the present invention is to provide a magnetic condensation nucleus for a magnetic core floc water separation process, so as to solve the problems of "flocculent runaway" and "magnetic runaway" caused by poor combination of magnetic core and floc mass mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A magnetic condensation nucleus for a magnetic core flocculent water separation treatment process comprises the following raw materials: ferroferric oxide powder and PTFE emulsion. The preparation method of the magnetic condensation nucleus comprises the following steps: step S1: washing the ferroferric oxide powder with deionized water to remove impurities generated during production, storage and transportation and oil stains on the surface of ferroferric oxide powder particles; step S2: dehydrating the washed ferroferric oxide powder, and then uniformly mixing it with the PTFE emulsion for impregnation and coating treatment, granulating the mixed slurry through high-temperature rotary spraying, and further drying after granulation; step S3: plasma treating the powder after impregnation and drying, so as to treat the powder with excited plasma gas to activate and modify the surface of the coated film.

[0007] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0008] In an optional solution: in the step S2, after the ferrosoferric oxide powder is dehydrated, the moisture content of the ferrosoferric oxide powder is controlled at 20-40%.

[0009] In an optional solution: in step S2, the content of PTFE emulsion is 70-90% of the ferrosoferric oxide powder.

[0010] In an optional solution: in step S2, after the slurry is granulated and dried, it is sieved to obtain a powder of 200-300 meshes.

[0011] In an optional solution, the moisture content of the slurry after granulation is controlled at 10-30%.

[0012] In an optional embodiment: the PTFE emulsion consists of nano powder, nonionic surfactant, pH regulator, dispersant, modification additive and catalyst.

[0013] In an optional embodiment, the dispersant is ammonium perfluorooctanoate, and the pH regulator is ammonia water.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention adjusts the surface properties of ferroferric oxide to change the surface properties of the magnetic core (magnetic species), wherein after the surface properties of ferroferric oxide are adjusted, the surface is rougher, the specific surface area is larger, there are more points that are easily attached, and the surface presents honeycomb or porosity, so as to increase its adsorption and capture and capture capabilities, improve its double electric layer structure and properties, make its hydration shell thinner, and be more easily compressed during the flocculation reaction process, improve its hydrophilicity, and make its dispersion, bridging, capture and other processes of the flocculation process in water smoother.

[0016] The present invention selects to coat the surface of the ferroferric oxide powder particles first, covering a layer of corrosion-resistant and wear-resistant organic film, and then modifying the coating on the surface of the particles, so as to achieve the purpose of retaining magnetism while changing the surface properties. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments listed in the present invention are only used to illustrate the present invention and are not used to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not deviate from the spirit and scope of the present invention. Example 1

[0018] This embodiment provides a method for preparing magnetic condensation nuclei for a magnetic core flocculation water separation process, the method comprising the following steps:

[0019] Step S100: using 100-400 mesh ferroferric oxide powder as the main raw material, firstly washing it with deionized water, and adding a surfactant during the washing process to remove impurities generated during production and storage and transportation and oil stains on the surface of ferroferric oxide powder particles;

[0020] Step S200: the washed ferroferric oxide powder is first dehydrated to control the moisture content to 20%, and then subjected to an immersion coating treatment;

[0021] That is, it is uniformly mixed with PTFE emulsion, the mixing ratio is 70% of magnetic powder, the mixed slurry is granulated by high-temperature rotary spraying, and then further dried after granulation to control the moisture content at 10%. The dried powder is sieved to obtain 200-300 mesh powder. The PTFE emulsion used here is mainly composed of PTFE particles (nano powder), non-ionic surfactant, dispersant (ammonium perfluorooctanoate), PH regulator (ammonia water), and other trace modified additives and catalysts.

[0022] Step S300: The powder after impregnation and drying is subjected to plasma treatment again, so as to treat the powder with excited plasma gas, so as to activate and modify the surface of the film body of the film. The surface of the modified PTFE substrate becomes rough from a relatively smooth state, and exhibits a porous property. The above appearance is presented because the edge of its surface is etched, oxidized and peeled off by plasma. The active particles and polar groups induced by plasma will also cross-link with the surface of the PTFE film to form an unsaturated surface structure, and then interact with nitrogen and oxygen in the air to obtain N and O outer ions, increase its hydrophilicity, and improve its charge distribution and polarity strength, so that it is easier to bridge and attract the flocs, and easier to become a condensation nucleus in the flocculation reaction process. Example 2

[0023] This embodiment provides a method for preparing magnetic condensation nuclei for a magnetic core flocculation water separation process, the method comprising the following steps:

[0024] Step S100: using 100-400 mesh ferroferric oxide powder as the main raw material, firstly washing it with deionized water, and adding a surfactant during the washing process to remove impurities generated during production and storage and transportation and oil stains on the surface of ferroferric oxide powder particles;

[0025] Step S200: the washed ferroferric oxide powder is first dehydrated to control the moisture content at 40%, and then subjected to an immersion coating treatment;

[0026] That is, it is uniformly mixed with PTFE emulsion, the mixing ratio is 90% of magnetic powder, the mixed slurry is granulated by high-temperature rotary spraying, and then further dried after granulation to control the moisture content at 10%. The dried powder is sieved to obtain 200-300 mesh powder. The PTFE emulsion used here is mainly composed of PTFE particles (nano powder), non-ionic surfactant, dispersant (ammonium perfluorooctanoate), PH regulator (ammonia water), and other trace modified additives and catalysts.

[0027] Step S300: The powder after impregnation and drying is subjected to plasma treatment again, so as to treat the powder with excited plasma gas, so as to activate and modify the surface of the film body. The surface of the modified PTFE substrate becomes rough from a relatively smooth state, and exhibits porous properties. The above appearance is presented because the edge of its surface is etched, oxidized and peeled off by plasma. The active particles and polar groups induced by plasma will also cross-link with the surface of the PTFE film to form an unsaturated surface structure, and then interact with nitrogen and oxygen in the air to obtain N and O outer ions, increase its hydrophilicity, and improve its charge distribution and polarity strength, making it easier to bridge and attract the flocs, and easier to become a condensation nucleus in the flocculation reaction process.

[0028] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A magnetic condensation nucleus for magnetic core flocculation water separation treatment process, It is characterized in that The raw materials include: ferroferric oxide powder and PTFE emulsion; The method for preparing the magnetic condensation nuclei comprises the following steps: Step S1: washing the ferroferric oxide powder with deionized water to remove impurities generated during production, storage and transportation and oil stains on the surface of the ferroferric oxide powder particles; Step S2: the washed ferroferric oxide powder is dehydrated, and then uniformly mixed with the PTFE emulsion for impregnation and coating treatment, the mixed slurry is granulated by high-temperature rotary spraying, and then further dried after granulation to obtain powder; Step S3: Plasma treatment is performed on the powder after immersion and drying, so that the powder is treated with excited plasma gas to activate and modify the surface of the film body coated thereon.

2. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 1, It is characterized in that In the step S2, after the ferrosoferric oxide powder is dehydrated, the moisture content of the ferrosoferric oxide powder is controlled at 20-40%.

3. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 1, It is characterized in that In the step S2, the content of the PTFE emulsion is 70-90% of the ferrosoferric oxide powder.

4. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 1, It is characterized in that In the step S2, after the slurry is granulated and dried, it is sieved to obtain a powder of 200-300 meshes.

5. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 4, It is characterized in that The moisture content of the slurry after granulation is controlled at 10-30%.

6. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 1, It is characterized in that The PTFE emulsion consists of nano powder, nonionic surfactant, pH regulator, dispersant, modification additive and catalyst.

7. The magnetic condensation nuclei used in the magnetic core flocculation water separation process according to claim 6, It is characterized in that The dispersant is ammonium perfluorooctanoate, and the pH adjuster is ammonia water.