An activated carbon-based composite filter element

Abstract

The present invention relates to an activated carbon-based composite filter element, which comprises a filter element housing having a first flow channel, the two ends of the flow channel being an inlet end and an outlet end respectively, and filter media being installed in the flow channel. It is characterized in that: the filter media sequentially includes a first filter layer, a second filter layer and a third filter layer from the inlet end to the outlet end direction. The filter media in the first filter layer is silver-loaded activated carbon, the filter media in the second filter layer is graphene-loaded activated carbon, and the filter media in the third filter layer is unmodified activated carbon, so as to solve the problem of limited water purification effect of existing water purification filter elements.

Description

Technical Field

[0001] The present invention relates to the field of water purification filters, and more particularly to an activated carbon-based composite filter element. Background Art

[0002] The quality of end-use water is related to people's health. With the improvement of people's requirements for water quality, higher requirements are also put forward for water treatment technologies, especially for the problem of secondary pollution of end-use water generated during pipeline network transportation. End-use water purification technology is one of the important ways to solve the above problems. In end-use water purification technology, the commonly used activated carbon adsorption method can remove various pollutants in water through adsorption, catalysis and other means, realizing the deep purification of end-use water and ensuring water use safety.

[0003] Different pollutant molecules have different molecular structures and sizes. The higher the degree of matching between them and the pore structure and surface chemical properties of activated carbon, the more ideal the adsorption efficiency. For example, heavy metal ions have a small size, and theoretically, microporous activated carbon has an ideal adsorption effect on them. However, the hydrophobic nature of most of the activated carbon surface leads to an unsatisfactory adsorption efficiency. Some heavy metal ions in the form of oxygen-containing anions generate electrostatic repulsion with the negative charges on the activated carbon surface, and it is easy to reach saturation and cause secondary release pollution; the residual disinfectants and disinfection by-products have a small size, and the adsorption efficiency of microporous activated carbon for them is relatively ideal. For emerging organic pollutants, their molecular sizes are usually large, and the adsorption capacity of microporous activated carbon is often unsatisfactory. The effect of activated carbon on pathogenic microorganisms is limited, and on the contrary, it may cause the problem of microbial growth due to the organic matter adsorbed on the surface. In summary, for various problems existing in water, a good deep purification effect cannot be achieved through one type of activated carbon; in addition, activated carbon only adsorbs, intercepts and enriches pollutant molecules, and most of the adsorbed pollutants cannot be degraded or transformed, resulting in potential secondary release risks.

[0004] Therefore, some people are averse to the proposal of using activated carbon as the basis, combining the advantages of different types of activated carbon organically, and achieving the purpose of reducing the risk of secondary release by synergistically adsorbing, transforming or degrading pollutants in water to completely remove them. For example, the patent with the publication number CN108585068A discloses a method for manufacturing an activated carbon rod, which includes activated carbon, magnesium porphyrin compound (natural deodorant), nano-bentonite, calcium-based saponite, sodium-based saponite (bacterial inhibitor), etc. The patent with the publication number CN107158805A discloses a multifunctional composite ceramic filter element prepared by a slip casting process using activated carbon, kaolin, diatom mud, bauxite, magnesium oxide, calcium-based bentonite, binder, deflocculation, organic pore former, inorganic pore forming, and nano-exchanger as raw materials, which is loaded with activated carbon, pore former, and nano-exchanger. The patent with the publication number CN108722015A discloses a filter element solution composed of composite porous carbon, grafted amphoteric chitosan, and modified titanium dioxide. Currently, when preparing filter elements, various water purification materials are added, and the types are numerous. It is difficult to trace the safety of each material during use, and the mixing uniformity will also affect the performance of the filter element.

[0005] In addition, in water purification products, direct filling of activated carbon is a commonly used method for manufacturing filter elements. The filter element prepared by this filling method is easy to manufacture, has a large water throughput during use and does not require a booster pump, and does not produce waste water. However, due to the shortcomings described above, when the flow rate is relatively high, the contact time between pollutant molecules and activated carbon is insufficient, resulting in unqualified removal effects. Summary of the Invention

[0006] The present invention aims to provide an activated carbon-based composite filter element to solve the problem of limited water purification effect of existing water purification filter elements.

[0007] The specific solution is as follows:

[0008] An activated carbon-based composite filter element includes a filter element housing with a flow channel. The two ends of the flow channel are respectively an inlet end and an outlet end. A filter material is installed in the flow channel. The filter material sequentially includes a first filter layer, a second filter layer, and a third filter layer from the inlet end to the outlet end. The filter material in the first filter layer is silver-loaded activated carbon, the filter material in the second filter layer is graphene-loaded activated carbon, and the filter material in the third filter layer is unmodified activated carbon.

[0009] Preferably, the particle size of the silver-loaded activated carbon is 8-20 mesh, the particle size of the graphene-loaded activated carbon is 20-40 mesh, and the particle size of the unmodified activated carbon is 8-40 mesh.

[0010] Preferably, the volume ratio of silver-loaded activated carbon, graphene-loaded activated carbon, and unmodified activated carbon in the filter material is 3-8:1-6:1.

[0011] Preferably, the first filter layer is a first carbon block made of silver-loaded activated carbon, and the second filter layer is a second carbon block made of graphene-loaded activated carbon.

[0012] Preferably, the thickness of the first carbon block is 5 - 10 mm, and the thickness of the second carbon block is 5 - 10 mm.

[0013] Preferably, the preparation method of the first carbon block is as follows

[0014] S11. Prepare a silver-loaded activated carbon slurry, which consists of an inorganic binder and silver-loaded activated carbon;

[0015] S21. Place the block-shaped filter element mold into the silver-loaded activated carbon slurry to make a silver-loaded activated carbon block-shaped filter element;

[0016] S31. Dry the silver-loaded activated carbon block-shaped filter element processed in step S21 so that the silver-loaded activated carbon block-shaped filter element dries and forms. After forming, remove the block-shaped filter element mold to obtain the first carbon block.

[0017] Preferably, the preparation method of the second carbon block is as follows:

[0018] S12. Prepare a graphene-loaded activated carbon slurry, which consists of an inorganic binder and graphene-loaded activated carbon;

[0019] S22. Place the block-shaped filter element mold into the graphene-loaded activated carbon slurry to make a graphene-loaded activated carbon block-shaped filter element;

[0020] S32. Dry the graphene-loaded activated carbon block-shaped filter element processed in step S22 so that the graphene-loaded activated carbon block-shaped filter element dries and forms. After forming, remove the block-shaped filter element mold to obtain the second carbon block.

[0021] Preferably, the first filter layer and the second filter layer are integrally formed into a hollow columnar filter rod, and the opposite ends of the filter rod are closed; the third filter layer is located at the water outlet end of the filter element housing, and there is a partition in the filter element housing corresponding to the connection of the first filter layer and the second filter layer, and the middle of the partition has a mounting hole matching the filter rod.

[0022] Preferably, the preparation method of the filter rod is as follows:

[0023] S13. Prepare a graphene-loaded activated carbon slurry and a graphene-loaded activated carbon slurry. The graphene-loaded activated carbon slurry consists of an inorganic binder and graphene-loaded activated carbon, and the graphene-loaded activated carbon slurry consists of an inorganic binder and graphene-loaded activated carbon;

[0024] S23. Place one section of the rod-shaped filter element mold into one of the graphene-loaded activated carbon slurries or the graphene-loaded activated carbon slurries, and rotate it at a certain speed in the corresponding activated carbon slurry to make the corresponding activated carbon slurry adsorb on the surface of the rod-shaped filter element mold, and pre-dry it to obtain a corresponding activated carbon layer with a certain thickness;

[0025] S33. Place the other section of the rod-shaped filter element mold into the other of the graphene-loaded activated carbon slurries or the graphene-loaded activated carbon slurries, and rotate it at a certain speed in the corresponding activated carbon slurry to make the corresponding activated carbon slurry adsorb on the surface of the rod-shaped filter element mold, and pre-dry it to obtain a corresponding activated carbon layer with a certain thickness;

[0026] S43. Dry the graphene-loaded activated carbon block-shaped filter element processed in step S33 to make the graphene-loaded activated carbon block-shaped filter element dry and form. After forming, remove the rod-shaped filter element mold, and install plugs at both ends to obtain a filter rod.

[0027] Preferably, the first filter layer and the second filter layer are integrally formed hollow columnar filter rods, and the opposite ends of the filter rods are closed; the filter rods are arranged along the axial direction of the filter element housing, and there is a partition in the filter element housing corresponding to the connection of the first filter layer and the second filter layer. The middle of the partition has a mounting hole that matches the filter rod, and divides the space between the outer wall of the filter rod and the inner wall of the filter element housing into mutually isolated first cavities and second cavities. Among them, the first cavity is close to the water inlet end, the second cavity is close to the water outlet end, the fourth filter layer is filled in the first cavity, the third filter layer is filled in the second cavity, and the filter material in the fourth filter layer is unmodified activated carbon.

[0028] The activated carbon-based composite filter element provided by the present invention has the following advantages compared with the prior art: The activated carbon-based composite filter element provided by the present invention organically combines modified and unmodified activated carbons, synergizes the advantages of particle filling and forming, and flexibly meets different water purification technologies and usage requirements. Among them, the modified silver-loaded activated carbon and graphene-loaded activated carbon can improve the water purification efficiency, adsorb and transform heavy metal ions, degrade organic substances and inhibit the growth of microorganisms at the same time. Description of the Drawings

[0029] Figure 1 Shows a schematic diagram of the activated carbon-based composite filter element in Example 1.

[0030] Figure 2 Shows a table diagram of the experimental data of the removal of lead ions by the No. 1 composite filter element.

[0031] Figure 3 Shows a table diagram of the experimental data of the removal of lead ions by the No. 2 composite filter element.

[0032] Figure 4The figure shows a table of experimental data on the removal of lead ions by the 3# composite filter element.

[0033] Figure 5 The figure shows a table of experimental data on the removal of lead ions by the 4# composite filter element.

[0034] Figure 6 The figure shows a schematic diagram of the activated carbon-based composite filter element in Example 2.

[0035] Figure 7 The figure shows a schematic diagram of the activated carbon-based composite filter element in Example 3.

[0036] Figure 8 The figure shows a schematic diagram of the activated carbon-based composite filter element in Example 4. Detailed implementation manners

[0037] To further illustrate each embodiment, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be combined with the relevant descriptions in the specification to explain the operating principle of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation manners.

[0039] As Figure 1 shown, this embodiment provides an activated carbon-based composite filter element, including a filter element housing 10 having a flow channel. The two ends of the flow channel are respectively a water inlet end 11 and a water outlet end 12, and filter media are installed in the flow channel.

[0040] Among them, the filter media sequentially include a first filter layer 21, a second filter layer 22, and a third filter layer 23 from the water inlet end 11 to the water outlet end 12. The filter media in the first filter layer 21 is silver-loaded activated carbon, the filter media in the second filter layer 22 is graphene-loaded activated carbon, and the filter media in the third filter layer 23 is unmodified activated carbon.

[0041] Among them, the silver-loaded activated carbon in the first filter layer 21 is prepared by in-situ reduction on the basis of nano-zero-valent iron-loaded activated carbon. The equation for in-situ reduction is 2Ag + +Fe0=2Ag+Fe 2+. During the in-situ reduction process, no reducing agent needs to be added, so no other substances will be introduced, ensuring the safety of the activated carbon. The particle size of the silver-loaded activated carbon is preferably 8-20 mesh, which can convert heavy metal ions or degrade some organic substances (such as chlorinated volatile organic compounds), convert them into low-toxic or non-toxic inorganic substances and / or small-molecule organic substances, and can inhibit the growth of microorganisms on the surface of the activated carbon to improve microbial safety.

[0042] The graphene-loaded activated carbon in the second filter layer 22 is obtained by modifying the acidified activated carbon with an aqueous solution of graphene oxide. Through the mutual adsorption and complexation between the activated carbon and graphene, the stacking of graphene itself is reduced, and at the same time, the adsorption performance of the activated carbon itself is synergistically improved. Among them, the particle size of the graphene-loaded activated carbon is preferably 20-40 mesh. The function of this second filter layer 22 is to quickly adsorb the small-molecule organic substances that are not adsorbed and degraded by the first filter layer 21, improve the adsorption capacity of the activated carbon, extend the service life, and can also adsorb the silver ions released from the first filter layer 21 to reduce the potential health risks brought by the upper-layer activated carbon.

[0043] The filter material in the third filter layer 23 is unmodified activated carbon, which can further filter the particulate matter in the water to ensure the cleanliness of the effluent, and can also improve the taste of the water. The particle size of the unmodified activated carbon is preferably 8-40 mesh.

[0044] The activated carbon-based composite filter element provided in this embodiment organically combines modified and unmodified activated carbons, synergistically combines the advantages of particle filling and molding, and flexibly meets different water purification technologies and usage requirements. Among them, the modified silver-loaded activated carbon and graphene-loaded activated carbon can improve the water purification efficiency, adsorb and convert heavy metal ions, degrade organic substances and inhibit the growth of microorganisms at the same time.

[0045] Reference Figure 1 , this embodiment takes a water purifying kettle as an example to verify the performance of the activated carbon-based composite filter element. Among them, the filter element housing 10 is made of polypropylene, and two layers of filter screens 13 are installed in the flow channel to separate three spaces in the filter element housing 10. The three spaces are filled with silver-loaded activated carbon, graphene-loaded activated carbon and unmodified activated carbon from the water inlet end 11 to the water outlet end 12. A layer of PP cotton 14 is installed on the water inlet end to achieve the purpose of initial filtration of the incoming water.

[0046] In this embodiment, 4 composite filters are prepared, which are respectively defined as Filter 1#, Filter 2#, Filter 3# and Filter 4#. Among them, the volume ratio of silver-loaded activated carbon, graphene-loaded activated carbon and unmodified activated carbon in Filter 1# is 8:1:1; the volume ratio of silver-loaded activated carbon, graphene-loaded activated carbon and unmodified activated carbon in Filter 2# is 5:4:1; the volume ratio of silver-loaded activated carbon, graphene-loaded activated carbon and unmodified activated carbon in Filter 3# is 3:6:1; the volume ratio of silver-activated carbon, graphene-loaded activated carbon and unmodified activated carbon in Filter 4# is 0:0:10.

[0047] The performance test adopts the method of continuous lead ion spiking experiment. The experimental device is automatically controlled, and the flow rate and effluent flow are automatically recorded. The dilution method is used to prepare the solution in the spiking device, and samples are taken under different flow rate conditions. In this embodiment, lead ions are used as the spiking substance, and the whole-process spiking method is adopted. The initial concentration of lead ions in the spiking solution is 100 μg / L, the pH is about 6.50, the test flow rate is about 0.45 mL / min, and the water throughput is 1000 L. Samples are taken at 0 L, 10 L, 50 L, 100 L, 200 L, 400 L, 600 L, 800 L and 1000 L during the spiking experiment. Blank samples and filtered samples are taken respectively, and two parallel samples are taken for each. Each time, 10 mL of samples are taken, filtered through a 0.22 μm membrane, mixed with 0.1 M nitric acid and stored, and then tested by ICP-MS.

[0048] The specific results are as Figures 2 - 5 shown. The results show that under the above test conditions, Filter 1# composite filter can remove more than 90% of lead ions, Filter 2# composite filter can remove more than 70% of lead ions, and Filter 3# composite filter can remove more than 60% of lead ions. Their removal rates of lead ions are significantly better than those of unmodified activated carbon. In addition, the larger the proportion of silver-loaded activated carbon, the better the removal rate of lead ions, which proves the effect of silver-loaded activated carbon in converting heavy metal ions. Moreover, as the water flux increases, the reduction of the removal efficiency of lead ions is not obvious, while the reduction degree of the removal efficiency of lead ions by unmodified activated carbon is larger.

[0049] Embodiment 2

[0050] Referring to Figure 6 , this embodiment also provides an activated carbon-based composite filter. Its structure is roughly the same as that of the activated carbon-based composite filter provided in Embodiment 1. The difference is that the first filter layer 21 is a first carbon block made of silver-loaded activated carbon, and the second filter layer 22 is a second carbon block made of graphene-loaded activated carbon. Compared with the granular silver-loaded activated carbon and granular graphene-loaded activated carbon in Embodiment 1, the massive silver-loaded activated carbon and massive graphene-loaded activated carbon can be directly placed in the filter housing 10 without a filter screen and can be flexibly used in different scenarios by adjusting the usage ratio.

[0051] Furthermore, the thickness of the first carbon block is 5-10 mm, and the thickness of the second carbon block is 5-10 mm.

[0052] Among them, the preparation method of the first carbon block is as follows.

[0053] S11: Prepare a silver-loaded activated carbon slurry, which is composed of an inorganic binder and silver-loaded activated carbon.

[0054] S21: Place the block-shaped filter element mold into the silver-loaded activated carbon slurry to make a silver-loaded activated carbon block-shaped filter element.

[0055] S31: Dry the silver-loaded activated carbon block-shaped filter element processed in step S21 so that the silver-loaded activated carbon block-shaped filter element dries and forms. After forming, remove the block-shaped filter element mold to obtain the first carbon block.

[0056] The preparation method of the second carbon block is as follows:

[0057] S12: Prepare a graphene-loaded activated carbon slurry, which is composed of an inorganic binder and graphene-loaded activated carbon.

[0058] S22: Place the block-shaped filter element mold into the graphene-loaded activated carbon slurry to make a graphene-loaded activated carbon block-shaped filter element.

[0059] S32: Dry the graphene-loaded activated carbon block-shaped filter element processed in step S22 so that the graphene-loaded activated carbon block-shaped filter element dries and forms. After forming, remove the block-shaped filter element mold to obtain the second carbon block.

[0060] Example 3

[0061] Reference Figure 7 , this example also provides an activated carbon-based composite filter element, including a filter element housing 10 with a first flow channel. The two ends of the flow channel are respectively an inlet end 11 and an outlet end 12, and a filter medium is installed in the flow channel.

[0062] Among them, the filter medium sequentially includes a first filter layer 21, a second filter layer 22, and a third filter layer 23 from the inlet end 11 to the outlet end 12. The filter medium in the first filter layer 21 is silver-loaded activated carbon, the filter medium in the second filter layer 22 is graphene-loaded activated carbon, and the filter medium in the third filter layer 23 is unmodified activated carbon.

[0063] The first filter layer 21 and the second filter layer 22 are integrally formed hollow columnar filter rods, and the opposite ends of the filter rods are closed; the third filter layer 23 is located at the outlet end 12 of the filter element housing 10. There is a partition 15 corresponding to the connection of the first filter layer 21 and the second filter layer 22 in the filter element housing 10. The middle of the partition 15 has an installation hole matching the filter rod. The water flow direction of this activated carbon-based composite filter element is asFigure 7 As shown by the arrow direction. Compared with the activated carbon-based composite filter element in Embodiment 1 or Embodiment 2, the first filter layer 21 and the second filter layer 22 of the activated carbon-based composite filter element in this embodiment have water inlet and outlet from the side wall direction, and can have better filtering effect in the filtering occasion with small inner diameter.

[0064] The preparation method of the integrally formed hollow columnar filter rod is as follows:

[0065] S13. Prepare the graphene-loaded activated carbon slurry and the graphene-loaded activated carbon slurry. The graphene-loaded activated carbon slurry is composed of an inorganic binder and graphene-loaded activated carbon, and the graphene-loaded activated carbon slurry is composed of an inorganic binder and graphene-loaded activated carbon.

[0066] S23. Put one end of the rod-shaped filter element mold into one of the graphene-loaded activated carbon slurry or the graphene-loaded activated carbon slurry, and rotate it at a certain speed in the corresponding activated carbon slurry to make the corresponding activated carbon slurry adsorb on the surface of the rod-shaped filter element mold, and pre-dry it to obtain a corresponding activated carbon layer with a certain thickness.

[0067] S33. Put the other end of the rod-shaped filter element mold into the other of the graphene-loaded activated carbon slurry or the graphene-loaded activated carbon slurry, and rotate it at a certain speed in the corresponding activated carbon slurry to make the corresponding activated carbon slurry adsorb on the surface of the rod-shaped filter element mold, and pre-dry it to obtain a corresponding activated carbon layer with a certain thickness.

[0068] S43. Dry the graphene-loaded activated carbon block filter element processed by step S33 to make the graphene-loaded activated carbon block filter element dry and form. After forming, remove the rod-shaped filter element mold, and install plugs at both ends to obtain the filter rod.

[0069] Embodiment 4

[0070] Reference Figure 8 , this embodiment also provides an activated carbon-based composite filter element, including a filter element housing 10 with a flow channel. The two ends of the flow channel are respectively a water inlet end 11 and a water outlet end 12, and a filter medium is installed in the flow channel.

[0071] Among them, the filter medium includes a fourth filter layer 24, a first filter layer 21, a second filter layer 22, and a third filter layer 23 in sequence from the water inlet end 11 to the water outlet end 12. The filter medium in the first filter layer 21 is silver-loaded activated carbon, the filter medium in the second filter layer 22 is graphene-loaded activated carbon, and the filter media in the third filter layer 23 and the fourth filter layer 24 are both unmodified activated carbon.

[0072] The first filter layer 21 and the second filter layer 22 are integrally formed hollow columnar filter rods, and the opposite ends of the filter rods are closed; the filter rods are arranged along the axial direction of the filter element housing 10, and there is a partition 15 in the filter element housing 10 corresponding to the connection between the first filter layer 21 and the second filter layer 22. The middle of the partition 15 has a mounting hole matching the filter rod, and divides the space between the outer wall of the filter rod and the inner wall of the filter element housing 10 into a mutually isolated first cavity and a second cavity. The first cavity is close to the water inlet end, and the second cavity is close to the water outlet end. The fourth filter layer 24 is filled in the first cavity, and the third filter layer 23 is filled in the second cavity. The water flow direction of the activated carbon-based composite filter element is as Figure 8 shown by the arrow direction in

[0073] In this embodiment, the first filter layer 21 and the second filter layer 22 of the activated carbon-based composite filter element enter and exit water from the side wall direction, and can have a better filtering effect in the filtering occasion with a small inner diameter.

[0074] In addition, the preparation method of the filter rod is the same as that of the filter rod in Embodiment 3, and will not be elaborated here.

[0075] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all are within the protection scope of the present invention.

Claims

1. An activated carbon-based composite filter element, comprising a filter element housing having a first flow channel, with the two ends of the flow channel being an inlet end and an outlet end respectively, and a filter medium is installed in the flow channel, characterized in that: The filter media sequentially includes a first filter layer, a second filter layer, and a third filter layer from the water inlet end to the water outlet end. The filter media in the first filter layer is silver-loaded activated carbon, the filter media in the second filter layer is graphene-loaded activated carbon, and the filter media in the third filter layer is unmodified activated carbon; The first filter layer and the second filter layer are integrally formed into a hollow columnar filter rod, and the opposite ends of the filter rod are hermetically arranged; the third filter layer is located at the water outlet end of the filter element housing, and there is a partition in the filter element housing corresponding to the connection between the first filter layer and the second filter layer. The middle of the partition has a mounting hole that matches the filter rod; Or the first filter layer and the second filter layer are integrally formed into a hollow columnar filter rod, and the opposite ends of the filter rod are hermetically arranged; the filter rod is arranged along the axial direction of the filter element housing, and there is a partition in the filter element housing corresponding to the connection between the first filter layer and the second filter layer. The middle of the partition has a mounting hole that matches the filter rod, and divides the space between the outer wall of the filter rod and the inner wall of the filter element housing into a mutually isolated first cavity and a second cavity. The first cavity is close to the water inlet end, and the second cavity is close to the water outlet end. The first cavity is filled with a fourth filter layer, and the second cavity is filled with a third filter layer. The filter media in the fourth filter layer is unmodified activated carbon.

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