Multifunctional coupling reactor and treatment method thereof

Abstract

The invention discloses a multifunctional coupling reactor and a treatment method thereof, and relates to the technical field of environmental engineering and water treatment. According to the multifunctional coupling reactor designed by the invention, a vertical flow countercurrent contact layering process is adopted, and triple purification mechanisms of hydrophobic adsorption, ion exchange and chemical reduction are sequentially integrated, so that graded targeted removal of PFASs with different chain lengths is realized. The microporous coconut shell charcoal adsorption zone, the double quaternary ammonium group resin exchange zone and the sulfur-doped Fe3O4 / charcoal reduction zone have a synergistic effect, so that the limitations of low efficiency and poor adaptability of the traditional single technology under the coexistence condition of long-chain and short-chain PFASs are overcome; by means of the characteristics of high efficiency, sustainability and intelligence, the technology is suitable for three-stage deep purification of urban sewage plants, PFASs treatment of high-concentration industrial wastewater and in-situ remediation of polluted underground water, and has remarkable engineering application value and popularization potential.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental engineering and water treatment, and in particular to a multifunctional coupled reactor and a treatment method thereof. Background Art

[0002] Per- and polyfluoroalkyl substances (PFASs) are a class of synthetic organic fluorides widely used in industrial and consumer products such as waterproofing, oil repellents, surfactants, and firefighting foams. Due to their unique C–F bond structure, they exhibit extremely high chemical and thermal stability. They are also highly hydrophobic and lipid-soluble, making them difficult to degrade in environmental media and easily migrate through water bodies. This has become a major challenge in global water pollution control. PFASs can accumulate in water, soil, and in plants and animals. They have been shown to be hepatotoxic, endocrine disrupting, immunotoxic, and potentially carcinogenic, posing a serious threat to ecosystem safety and human health.

[0003] In the water environment, PFASs often exist in extremely low concentrations but chemically stable forms, mainly including long-chain species with strong hydrophobicity (such as PFOA, PFOS) and short-chain substitutes with higher hydrophilicity (such as PFBA, PFBS, etc.). Due to the differences in chain length and functional groups, the physical and chemical behaviors of these two types of PFASs in water bodies are significantly different: long-chain PFASs easily undergo hydrophobic interactions with the surface of solid-phase adsorbents and are enriched, but traditional adsorption materials are difficult to achieve efficient interception; short-chain PFASs, due to their enhanced water solubility, can penetrate conventional adsorption layers and are difficult to further capture in subsequent treatment units, resulting in high residual concentrations in the effluent. Existing single processes are often unable to simultaneously meet the needs of efficient removal and final degradation of long-chain and short-chain PFASs. Therefore, it is urgent to develop an integrated deep treatment technology that is both multifunctional and highly selective to achieve the synergistic interception and thorough mineralization of PFASs of different chain lengths.

[0004] Currently, commonly used PFASs treatment methods include granular activated carbon adsorption, membrane separation technology (such as nanofiltration and reverse osmosis), and advanced oxidation / reduction (ADR) technologies. However, these single technologies generally suffer from the following problems: adsorption methods have low removal efficiency for short-chain PFASs and pose a risk of penetration; while membrane technologies offer high interception efficiency, they face challenges such as membrane fouling and secondary treatment of concentrated liquids; and advanced oxidation / reduction (ADR) technologies have harsh operating conditions, high energy consumption, and poor adaptability to complex water quality conditions.

[0005] Therefore, a new solution to the above problems needs to be proposed. Summary of the Invention

[0006] The object of the present invention is to provide a multifunctional coupled reactor and a processing method thereof to solve the technical problems raised in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a multifunctional coupled reactor, comprising a reactor body, a bottom plate and a cover plate, wherein the bottom end of the reactor wall is fixedly connected to the bottom plate, and the top end of the reactor wall is fixedly connected to the cover plate;

[0008] The interior of the reactor body is sequentially provided with three layers of quick-install independent packing units from bottom to top, namely, a top packing unit, a middle packing unit, and a bottom packing unit. Each of the three layers of quick-install independent packing units is equipped with a snap-on buckle and a self-locking sealing ring to facilitate single-layer disassembly and replacement. The three layers of quick-install independent packing units cooperate with each other to form a countercurrent contact path of "upper reduction-middle exchange-lower adsorption" to achieve efficient layered removal of PFASs of different chain lengths;

[0009] The packing units are separated by a plurality of conical microporous sieve plates, wherein the plurality of conical microporous sieve plates include at least a first conical microporous sieve plate, a second conical microporous sieve plate, a third conical microporous sieve plate, a fourth conical microporous sieve plate, a fifth conical microporous sieve plate and a sixth conical microporous sieve plate;

[0010] A water inlet pipe is provided at the bottom plate position, and a water outlet pipe and a sampling pipe are respectively designed on both sides of the top of the reactor body.

[0011] Furthermore, the sieve plate pore diameters of the first conical microporous sieve plate, the second conical microporous sieve plate, the third conical microporous sieve plate, the fourth conical microporous sieve plate, the fifth conical microporous sieve plate, and the sixth conical microporous sieve plate are all 0.5 mm, and a plurality of water distribution holes are evenly arranged with an opening rate of ≥45% to enhance the distribution and contact of the liquid in each packing layer;

[0012] It has both solid-liquid separation and turbulence enhancement functions;

[0013] The inclination angles of the first conical microporous sieve plate, the second conical microporous sieve plate, the third conical microporous sieve plate, the fourth conical microporous sieve plate, the fifth conical microporous sieve plate and the sixth conical microporous sieve plate are all 45°±5°.

[0014] Furthermore, the top filler unit is a Fe3O4 / sulfur-doped biochar composite material with a Fe3O4 loading of ≥20wt%;

[0015] The Fe3O4 / sulfur-doped biochar composite material contains Fe3O4 in the form of magnetic clusters (particle size 50-100 nm) and sulfur element doped in the form of CS bonds (content 1.5-3.0 wt%); the biochar specific surface area is ≥600 m 2 / g, derived from straw pyrolysis (500℃ oxygen-limited);

[0016] Nano-zero-valent iron provides an electron source, breaking the C–F bonds in PFASs through chemical reduction, which is used for the defluorination and mineralization of full-chain PFASs.

[0017] Furthermore, the middle layer filler unit is a strongly basic anion exchange resin containing ether-bridged diquaternary ammonium groups;

[0018] The structural formula is

[0019] -CH2-N + (CH3)2-CH2-CH2-N + (CH3)3)

[0020] Exchange capacity ≥1.8mmol / g, adsorption capacity up to 120mg / g;

[0021] The middle layer filler unit is used to preferentially remove C4–C6 short-chain PFASs.

[0022] Furthermore, the bottom filler unit is a coconut shell-based microporous activated carbon activated by KOH, with a pore size distribution of 0.8-1.2 nm and a PFOS adsorption amount of ≥450 mg / g. The bottom filler unit is used for targeted adsorption of C≥8 long-chain PFASs.

[0023] Furthermore, a temperature control jacket is provided inside the outer wall of the reactor body for adjusting the reaction temperature through a temperature control medium, and an insulation layer water outlet pipe is provided at the temperature control jacket;

[0024] A pumping disc is provided on the inner side of the reactor body, and an air inlet pipe is connected to the bottom end of the pumping disc;

[0025] It also includes a steel frame, the reactor body is placed on the steel frame, the bottom plate is in contact with the steel frame, and the water inlet pipe and the air inlet pipe both pass through the steel frame;

[0026] The reactor body is entirely made of transparent material to facilitate online observation of the synergistic effect between the filler and the microorganisms.

[0027] A method for treating PFASs with a multifunctional coupled reactor comprises at least the following steps:

[0028] S1: Countercurrent contact, sewage enters from the bottom inlet pipe, passes through the bottom packing unit, middle packing unit and top packing unit in sequence, and passes through multiple conical microporous sieve plates in this process;

[0029] S2: Regeneration cycle, the separated saturated resin is regenerated with a 10 wt% NaCl / ethanol mixture, and the regeneration liquid is re-injected into the top packing unit for degradation.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The multifunctional coupled reactor designed in this invention utilizes a layered process with vertical flow and countercurrent contact, sequentially integrating a triple purification mechanism of hydrophobic adsorption, ion exchange, and chemical reduction to achieve the hierarchical, targeted removal of PFASs of varying chain lengths. The synergistic effects of the microporous coconut shell charcoal adsorption zone, the diquaternary ammonium resin exchange zone, and the sulfur-doped Fe₃O₄ / biochar reduction zone overcome the limitations of traditional single technologies, which suffer from low efficiency and poor adaptability when long- and short-chain PFASs coexist. Due to its high efficiency, sustainability, and intelligent nature, this technology is suitable for tertiary deep purification in municipal sewage treatment plants, PFASs treatment in high-concentration industrial wastewater, and in-situ remediation of contaminated groundwater, demonstrating significant engineering application value and potential for widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 It is a schematic structural diagram of the present invention as a whole;

[0034] Figure 2 A top view of the present invention;

[0035] Figure 3 It is a cross-sectional view of the present invention;

[0036] Figure 4 Schematic diagram of the conical microporous sieve plate of the present invention.

[0037] In the figure: 1. Reactor body; 2. Bottom plate; 3. Cover plate; 4. Top layer packing unit; 5. Middle layer packing unit; 6. Bottom layer packing unit; 7. First conical microporous sieve plate; 8. Second conical microporous sieve plate; 9. Third conical microporous sieve plate; 10. Fourth conical microporous sieve plate; 11. Fifth conical microporous sieve plate; 12. Sixth conical microporous sieve plate; 13. Water outlet pipe; 14. Sampling tube; 15. Insulation layer water outlet pipe; 16. Water inlet pipe; 17. Air inlet pipe; 18. Steel frame. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] This invention proposes a vertical countercurrent layered contact configuration of "upper reduction - middle exchange - lower adsorption." This design is based on the differences in the distribution coefficients and molecular interactions of PFASs of different chain lengths: the bottom hydrophobic adsorption zone preferentially enriches long-chain PFASs, the middle ion exchange zone efficiently captures short-chain PFASs, and the top chemical reduction zone achieves deep mineralization of residual PFASs and desorption products through Fe3O4 / sulfur-doped biochar catalytic cleavage of C-F bonds. The countercurrent mode enhances the contact time and mass transfer efficiency between the pollutants and the functional layer, which is beneficial for improving the overall removal rate and reducing the volume footprint, as follows:

[0040] Example 1:

[0041] See also Figure 1-Figure 4 A multifunctional coupled reactor comprises a reactor body 1, a bottom plate 2 and a cover plate 3, wherein the bottom end of the reactor wall 1 is fixedly connected to the bottom plate 2, and the top end of the reactor wall 1 is fixedly connected to the cover plate 3;

[0042] The interior of the reactor body 1 is sequentially provided with three layers of quick-install independent packing units from bottom to top, namely, the top packing unit 4, the middle packing unit 5, and the bottom packing unit 6. Each of the three layers of quick-install independent packing units is equipped with a snap-on buckle and a self-locking sealing ring to facilitate single-layer disassembly and replacement. The three layers of quick-install independent packing units cooperate with each other to form a countercurrent contact path of "upper reduction - middle exchange - lower adsorption", so as to achieve efficient layered removal of PFASs of different chain lengths;

[0043] The packing units are separated by a plurality of conical microporous sieve plates, which include at least a first conical microporous sieve plate 7, a second conical microporous sieve plate 8, a third conical microporous sieve plate 9, a fourth conical microporous sieve plate 10, a fifth conical microporous sieve plate 11 and a sixth conical microporous sieve plate 12;

[0044] A water inlet pipe 16 is provided at the bottom plate 2 , and a water outlet pipe 13 and a sampling pipe 14 are respectively provided on both sides of the top of the reactor body 1 .

[0045] The sieve plate pore diameters of the first conical microporous sieve plate 7, the second conical microporous sieve plate 8, the third conical microporous sieve plate 9, the fourth conical microporous sieve plate 10, the fifth conical microporous sieve plate 11 and the sixth conical microporous sieve plate 12 are all 0.5 mm, with a number of water distribution holes evenly arranged and an opening rate of ≥45% to enhance the distribution and contact of the liquid in each packing layer;

[0046] It has both solid-liquid separation and turbulence enhancement functions;

[0047] The inclination angles of the first conical microporous sieve plate 7 , the second conical microporous sieve plate 8 , the third conical microporous sieve plate 9 , the fourth conical microporous sieve plate 10 , the fifth conical microporous sieve plate 11 and the sixth conical microporous sieve plate 12 are all 45°±5°.

[0048] (1) Enhanced liquid-solid contact: The water distribution holes can evenly distribute the incoming water to the filler particle layer, significantly increasing the contact area between the water flow and the filler surface, thereby improving the mass transfer rate and reaction efficiency;

[0049] (2) Solid-liquid separation: The screen structure can intercept filler particles, prevent the particles from being washed out with the water flow, and achieve efficient separation of the water phase and the solid phase;

[0050] (3) Uniform flow: The synergistic effect of the pore structure and the water distribution holes can balance the flow field, avoid channelization, and ensure that the hydraulic residence time in the entire packing layer is consistent.

[0051] The top filler unit 4 is a Fe3O4 / sulfur-doped biochar composite material with a Fe3O4 loading of ≥20 wt%;

[0052] In the Fe3O4 / sulfur-doped biochar composite material, Fe3O4 is loaded in the form of magnetic clusters (particle size 50-100nm), and sulfur is doped in the form of CS bonds (content 1.5-3.0wt%); the biochar specific surface area ≥600m 2 / g, derived from straw pyrolysis (500℃ oxygen-limited);

[0053] Nano-zero-valent iron provides an electron source, breaking the C–F bonds in PFASs through chemical reduction, which is used for the defluorination and mineralization of full-chain PFASs.

[0054] The middle filler unit 5 is a strong basic anion exchange resin containing ether-bridged diquaternary ammonium groups;

[0055] The structural formula is

[0056] -CH2-N + (CH3)2-CH2-CH2-N + (CH3)3)

[0057] Exchange capacity ≥1.8mmol / g, adsorption capacity up to 120mg / g;

[0058] The middle packing unit 5 is used to preferentially remove C4–C6 short-chain PFASs.

[0059] The bottom filler unit 6 is a coconut shell-based microporous activated carbon activated by KOH, with a pore size distribution of 0.8–1.2 nm and a PFOS adsorption capacity of ≥450 mg / g. The bottom filler unit 6 is used for targeted adsorption of C≥8 long-chain PFASs.

[0060] A temperature control jacket is provided inside the outer wall of the reactor body 1 for adjusting the reaction temperature through a temperature control medium, and an insulation layer outlet pipe (15) is provided at the temperature control jacket;

[0061] An air pump disc 19 is provided on the inner side of the reactor body 1, and an air inlet pipe 17 is connected to the bottom end of the air pump disc 19;

[0062] It also includes a steel frame 18, the reactor body 1 is placed on the steel frame 18, the bottom plate 2 is in contact with the steel frame 18, and the water inlet pipe 16 and the air inlet pipe 17 both pass through the steel frame 18;

[0063] The reactor body 1 is made entirely of transparent material to facilitate online observation of the synergistic effect between the filler and the microorganisms.

[0064] Microbial culture media includes nutrients and target pollutants. Nutrients, such as carbon sources, nitrogen sources, and trace elements, provide energy for microbial growth. Target pollutants are added to wastewater in the initial static mode to enrich and screen for microorganisms capable of degrading these pollutants.

[0065] Example 2:

[0066] Based on the above embodiment, a method for treating PFASs with a multifunctional coupled reactor is proposed, which includes at least the following steps:

[0067] S1: Countercurrent contact, sewage enters from the bottom water inlet pipe 16, passes through the bottom packing unit 6, the middle packing unit 5 and the top packing unit 4 in sequence, and passes through multiple conical microporous sieve plates in this process;

[0068] After entering through the bottom inlet pipe, contaminated water flows countercurrently through the three layers of packing mentioned above: deep physical adsorption of long-chain PFASs occurs in the sixth layer, selective exchange adsorption of short-chain PFASs is completed in the fifth layer, and chemical reduction pretreatment is carried out in the fourth layer. This layered cascade design, combined with the uniform velocity distribution and turbulence enhancement effects of the conical microporous sieve plate, maximizes liquid-solid contact efficiency and achieves the synergistic and efficient removal of PFASs of different chain lengths.

[0069] S2: Regeneration cycle, the separated saturated resin is regenerated with a 10 wt% NaCl / ethanol mixture, and the regeneration liquid is returned to the top filler unit 4 for degradation.

[0070] In summary:

[0071] The system utilizes a snap-action drawer unit design, supporting single-layer replacement and regeneration. The sieve plates feature 0.5mm pores and an open area ratio of ≥45%, enabling both solid-liquid separation and turbulence enhancement. The overall device boasts a compact structure, efficient operation, and support for online monitoring and intelligent control. It is suitable for the synergistic removal of complex pollutants such as PFASs, pesticides, and nitrogen, demonstrating significant energy-saving and carbon-reduction potential and promising application value.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A multifunctional coupled reactor, characterized in that: It comprises a reactor body (1), a bottom plate (2) and a cover plate (3), wherein the bottom end of the reactor wall (1) is fixedly connected to the bottom plate (2), and the top end of the reactor wall (1) is fixedly connected to the cover plate (3); The interior of the reactor body (1) is provided with three layers of quick-install independent packing units from bottom to top, namely, a top packing unit (4), a middle packing unit (5) and a bottom packing unit (6). Each of the three layers of quick-install independent packing units is equipped with a snap-on buckle and a self-locking sealing ring, which facilitates the disassembly and replacement of a single layer. The quick-install independent packing units can cooperate with each other to form a countercurrent contact path of "upper reduction - middle exchange - lower adsorption", so as to achieve efficient layered removal of PFASs with different chain lengths. The packing units are separated by a plurality of conical microporous sieve plates, wherein the plurality of conical microporous sieve plates at least include a first conical microporous sieve plate (7), a second conical microporous sieve plate (8), a third conical microporous sieve plate (9), a fourth conical microporous sieve plate (10), a fifth conical microporous sieve plate (11), and a sixth conical microporous sieve plate (12); A water inlet pipe (16) is provided at the bottom plate (2), and a water outlet pipe (13) and a sampling pipe (14) are respectively designed on both sides of the top of the reactor body (1).

2. A multifunctional coupled reactor and treatment method thereof according to claim 1, characterized in that: The sieve plate pore diameters of the first conical microporous sieve plate (7), the second conical microporous sieve plate (8), the third conical microporous sieve plate (9), the fourth conical microporous sieve plate (10), the fifth conical microporous sieve plate (11) and the sixth conical microporous sieve plate (12) are all 0.5 mm, a plurality of water distribution holes are evenly arranged and the opening rate is ≥45% to enhance the distribution and contact of the liquid in each packing layer; It has both solid-liquid separation and turbulence enhancement functions; The inclination angles of the first conical microporous sieve plate (7), the second conical microporous sieve plate (8), the third conical microporous sieve plate (9), the fourth conical microporous sieve plate (10), the fifth conical microporous sieve plate (11) and the sixth conical microporous sieve plate (12) are all 45°±5°.

3. A multifunctional coupled reactor according to claim 2, characterized in that: The top filler unit (4) is a Fe3O4 / sulfur-doped biochar composite material, with a Fe3O4 loading of ≥20 wt%; In the Fe3O4 / sulfur-doped biochar composite material, Fe3O4 is loaded in the form of magnetic clusters, and sulfur is doped in the form of CS bonds; Biochar specific surface area ≥ 600m 2 / g, derived from straw pyrolysis; The top filler unit (4) is used for defluorination and mineralization of full-chain PFASs.

4. A multifunctional coupled reactor according to claim 3, characterized in that: The middle layer filler unit (5) is a strongly basic anion exchange resin containing ether-bridged diquaternary ammonium groups; The structural formula is -CH2-N + (CH3)2-CH2-CH2-N + (CH3)3) Exchange capacity ≥1.8mmol / g, adsorption capacity can reach 120mg / g; The middle filler unit (5) is used to preferentially remove C4–C6 short-chain PFASs.

5. A multifunctional coupled reactor and treatment method thereof according to claim 4, characterized in that: The bottom filler unit (6) is a coconut shell-based microporous activated carbon activated by KOH, with a pore size distribution of 0.8-1.2 nm and a PFOS adsorption amount of ≥450 mg / g. The bottom filler unit (6) is used for targeted adsorption of C≥8 long-chain PFASs.

6. The multifunctional coupled reactor according to claim 1, characterized in that: A temperature control jacket is provided on the outer wall of the reactor body (1) for adjusting the reaction temperature through a temperature control medium, and a heat insulation layer outlet pipe (15) is provided on the temperature control jacket; A pumping disc (19) is provided on the inner side of the reactor body (1), and the bottom end of the pumping disc (19) is connected to an air inlet pipe (17); It also includes a steel frame (18), the reactor body (1) is placed on the steel frame (18), the bottom plate (2) is in contact with the steel frame (18), and the water inlet pipe (16) and the air inlet pipe (17) both pass through the steel frame (18); The reactor body (1) is entirely made of transparent material to facilitate online observation of the synergistic effect between the filler and the microorganisms.

7. A method for treating PFASs using a multifunctional coupled reactor, characterized by: At least the following steps are included: S1: Countercurrent contact, sewage enters from the bottom water inlet pipe (16), passes through the bottom packing unit (6), the middle packing unit (5) and the top packing unit (4) in sequence, and passes through multiple conical microporous sieve plates in the process; S2: Regeneration cycle, the separated saturated resin is regenerated with a 10 wt% NaCl / ethanol mixture, and the regeneration liquid is returned to the top packing unit (4) for degradation.

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