Heavy metal sewage treatment equipment

Abstract

The invention belongs to the field of sewage treatment equipment, and particularly discloses heavy metal sewage treatment equipment which comprises a pretreatment unit, a reactor module, a magnetic separation tank and a regeneration recovery module, the pretreatment unit comprises an alkali liquor adding pump and a reducing agent adding pump; the reactor module is communicated with the pretreatment unit, and a micro-nano aeration pipe, a high-speed stirrer and a magnetic ion exchanger are arranged in the reactor module; a magnetic attraction assembly, a membrane separation assembly and an adsorption net box are arranged in the magnetic separation tank, the membrane separation assembly comprises a nanofiltration membrane, and the adsorption net box is detachably mounted through a sliding rail; and the regeneration recovery module is provided with an acid / salt regeneration pool and an electrolysis recovery device. According to the equipment, reaction, separation, recovery and disinfection are integrated through a longitudinally overlapped modular structure, cyclic utilization of resources is achieved through magnetic separation and electrolytic recovery, efficient purification of heavy metal sewage is achieved, blockage and adsorbent loss are avoided in the operation process, and the heavy metal recovery rate is obviously increased.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment equipment, and more particularly to a heavy metal wastewater treatment equipment. Background Technology

[0002] Heavy metal wastewater (represented by chromium, nickel, cadmium, and copper) poses a continuous and severe threat to the ecological environment and human health. Current mainstream treatment processes convert heavy metal ions into hydroxide precipitates under alkaline conditions, followed by sludge-water separation and effluent compliance through a multi-stage series of units including sedimentation tanks, filter presses, filtration tanks, and disinfection tanks. However, long-term engineering practice has revealed systemic bottlenecks in this approach: nanoscale hydroxide nuclei easily form stable colloidal suspensions, resulting in heavy metal concentrations in the effluent far exceeding Class III surface water standards even after gravity settling; the strong adhesion of precipitates to equipment and filter media causes frequent clogging and inefficient stripping, leading to frequent operational interruptions; the lengthy process chain significantly increases equipment footprint, making in-situ deployment nearly impossible in mobile scenarios such as municipal pipeline inspection points, emergency rescue operations, or decentralized sewage discharge points, while transportation and unloading introduce secondary pollution risks; the high rate of adsorbent loss during the process results in insufficient heavy metal purity in the precipitated sludge, leading to high resource recovery costs and obstructed pathways. While improved solutions such as membrane separation, integrated equipment, and ion exchanger deposition devices have achieved breakthroughs in separation accuracy, footprint reduction, or solid-phase treatment efficiency to address the aforementioned pain points, they have also brought new imbalances, including soaring energy consumption, increased sludge production, or limited adaptability. These solutions have consistently failed to simultaneously meet the synergistic demands of high-efficiency purification, equipment intensification, and resource recycling. The industry is generally trapped in a dilemma of "single-indicator optimization, overall imbalance," thus urgently requiring a new technology that organically integrates efficient component separation, modular integration, and resource recycling to drive heavy metal wastewater treatment from passive end-of-pipe disposal to a closed-loop path of near-zero discharge and high-value resource utilization. Existing technologies urgently need improvement to address these issues. Summary of the Invention

[0003] The purpose of this invention is to provide a heavy metal wastewater treatment device that has the advantages of high-efficiency purification, compact equipment, and resource recycling.

[0004] To achieve the above objectives, the present invention provides the following solution: a heavy metal wastewater treatment device, comprising: a pretreatment unit, a reactor module, a magnetic separation tank, and a regeneration and recovery module; the pretreatment unit includes an alkali dosing pump and a reducing agent dosing pump; the reactor module is connected to the pretreatment unit and is internally equipped with micro / nano aeration pipes, a high-speed stirrer, and a magnetic ion exchanger; the magnetic separation tank contains a magnetic adsorption component, a membrane separation component, and an adsorption mesh box, the membrane separation component including a nanofiltration membrane, and the adsorption mesh box being detachable and installable; the regeneration and recovery module is equipped with an acid / salt regeneration tank and an electrolytic recovery device for regenerating the ion exchanger and recovering heavy metals.

[0005] Furthermore, the adsorption box contains an activated carbon-resin composite adsorbent and a stainless steel mesh.

[0006] Furthermore, the magnetic separation tank is equipped with a magnetic suction component at the bottom and a membrane separation component and an adsorption net box at the top; the adsorption net box can be horizontally moved to the regeneration and recycling module via a slide rail.

[0007] Furthermore, the micro-nano aeration tube has a bottom perforated tube structure, and the high-speed stirrer rotates at 300-500 rpm.

[0008] Furthermore, the magnetic attraction component is an electromagnet with a magnetic field strength ≥0.5T.

[0009] Furthermore, the acid / salt regeneration tank of the regeneration and recovery module is connected to an acid / salt solution storage device, which contains a 0.5-1.0 mol / L hydrochloric acid solution or a 10% sodium chloride solution.

[0010] Furthermore, the electrolytic recovery device employs titanium-coated electrodes with a current density of 100-200 A / m. 2 The purity of recovered heavy metals is ≥98%.

[0011] Furthermore, the heavy metal wastewater treatment equipment of this application also includes an ultraviolet disinfection unit, which is installed at the front end of the drain pipe.

[0012] Furthermore, a buffer water tank is provided between the membrane separation component and the adsorption mesh box.

[0013] Furthermore, the reducing agent dosing pump of the pretreatment unit is connected to a sulfite storage device, which contains a sulfite or ferrous sulfate solution for reducing Cr. 6+ To Cr 3+ .

[0014] Furthermore, the heavy metal wastewater treatment equipment of this application is equipped with a PLC control system, which links the pH sensor, ORP sensor, alkali dosing pump and reducing agent dosing pump to achieve pH value control with an accuracy of ±0.2.

[0015] Compared with the prior art, the present invention discloses at least the following beneficial effects:

[0016] This application provides a heavy metal wastewater treatment device that achieves efficient purification of heavy metal wastewater through the synergistic effect of a pretreatment unit, a reactor module, a magnetic separation tank, and a regeneration and recovery module. The modular design makes the device more compact, and the magnetic separation and electrolytic recovery realize the recycling of resources, giving it the advantages of efficient purification, compact equipment, and resource recycling. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the heavy metal wastewater treatment equipment of the present invention;

[0019] Figure 2 This is a schematic diagram of the magnetic separation tank in the heavy metal wastewater treatment equipment of the present invention;

[0020] Figure 3 This is a flowchart illustrating the working process of the heavy metal wastewater treatment equipment of the present invention.

[0021] Figure 4 This is a diagram illustrating the treatment process of the magnetic separation tank in the heavy metal wastewater treatment equipment of the present invention.

[0022] In the diagram: 100, Pretreatment unit; 101, pH sensor; 102, ORP sensor; 103, Alkali dosing pump; 104, Reducing agent dosing pump; 200, Reactor module; 201, Micro / nano aeration tube; 202, High-speed stirrer; 203, Magnetic ion exchanger; 300, Magnetic separation tank; 400, Magnetic suction assembly; 500, Membrane separation assembly; 501, Nanofiltration membrane; 600, Adsorption mesh box; 601, Activated carbon-resin composite adsorbent; 602, Slide rail; 700, Regeneration and recovery module; 701, Acid / salt regeneration tank; 702, Electrolysis recovery device; 800, Ultraviolet disinfection unit; 801, Drainage pipe; 900, Buffer tank. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Reference Figure 1 and Figure 2As shown, this embodiment of the invention provides a heavy metal wastewater treatment device, including a reactor module 200, a magnetic separation tank 300, and a regeneration and recovery module 700. The pretreatment unit 100 is equipped with a pH sensor 101, an ORP sensor 102, an alkali dosing pump 103, and a reducing agent dosing pump 104, used to adjust the pH of the wastewater to 8-10 and add a reducing agent. The reactor module 200 is connected to the pretreatment unit 100 and internally includes micro / nano aeration pipes 201, a high-speed stirrer 202, and a magnetic ion exchanger 203. The micro / nano aeration pipes 201 provide micro / nano bubbles to enhance reaction efficiency, the high-speed stirrer 202 promotes mixing of reactants, and the magnetic ion exchanger 203 is a nano-sized resin composite artificial zeolite with a particle size of 0.1-0.3 mm, used to adsorb heavy metal ions. The magnetic separation tank 300 incorporates a magnetic adsorption component 400, a membrane separation component 500, and an adsorption mesh box 600. The membrane separation component 500 includes a nanofiltration membrane 501 with a molecular weight cutoff ≤200 Da, used for further separation of heavy metal ions. The adsorption mesh box 600 is detachable via a slide rail 602 for easy maintenance and replacement. The regeneration and recovery module 700 includes an acid / salt regeneration tank 701 and an electrolytic recovery device 702 for recovering heavy metal resources.

[0026] The alkali dosing pump 103 of the pretreatment unit 100 can be a metering pump or a peristaltic pump, and the reducing agent dosing pump 104 can be connected to a sulfite, sulfide, or other reducing agent storage device, such as a sulfite storage device containing a sulfite or ferrous sulfate solution for reducing Cr. 6+ To Cr 3+ The reactor module 200's micro / nano aeration pipe 201 can adopt a bottom perforated pipe structure or a microporous aeration disc structure, and the high-speed stirrer 202's rotation speed can be adjusted to 300-500 rpm or higher. The magnetic ion exchanger 203 can be a magnetic resin or magnetic nanoparticle material. The magnetic separation tank 300's magnetic suction component 400 can adopt an electromagnet or permanent magnet, and the magnetic field strength can be adjusted to 0.5T or higher. The membrane separation component 500's nanofiltration membrane 501 can be a spiral wound or flat plate structure, with a pore size range of 1-10 nm. The adsorption box 600 can contain activated carbon, resin, or other adsorption materials, and the slide rail 602 can be made of aluminum alloy or stainless steel. The regeneration and recovery module 700's acid / salt regeneration tank 701 can be connected to acid storage devices of different concentrations, and the electrolytic recovery device 702 can adopt titanium-coated electrodes or other corrosion-resistant electrodes.

[0027] This technical solution, through an integrated design of pretreatment, reaction, separation, and recovery, solves the problems of low efficiency, easy clogging, large footprint, and difficult resource recovery in existing heavy metal wastewater treatment technologies. The pretreatment unit 100 adjusts the wastewater pH and adds a reducing agent to create suitable conditions for subsequent reactions. The reactor module 200 enhances reaction efficiency through micro-nano aeration and high-speed stirring, while the magnetic ion exchanger 203 selectively adsorbs heavy metal ions. The magnetic separation tank 300 utilizes a magnetic adsorption component 400 to rapidly separate the magnetic ion exchanger 203, and the membrane separation component 500 and adsorption mesh box 600 further purify the water. The regeneration and recovery module 700 recovers heavy metal resources through acid washing and electrolysis, achieving closed-loop treatment. This equipment is compact, easy to operate, and can efficiently remove heavy metals and achieve resource recovery, making it suitable for various heavy metal wastewater treatment scenarios.

[0028] In one specific embodiment, the device is equipped with a PLC control system that links the pH sensor 101, ORP sensor 102, alkali dosing pump 103, and reducing agent dosing pump 104 to achieve pH value control with an accuracy of ±0.2.

[0029] The design has been further optimized, with the adsorption box 600 containing activated carbon-resin composite adsorbent 601 and stainless steel mesh.

[0030] Activated carbon-resin composite adsorbent 601 is composed of activated carbon particles and ion exchange resin through physical mixing or chemical bonding. The activated carbon provides a porous adsorption surface, while the resin selectively captures heavy metal ions through ion exchange. The stainless steel mesh, with a mesh size of 200-300 mesh and a pore size of approximately 250 micrometers, ensures water flow while effectively intercepting adsorbent particles.

[0031] In one specific embodiment, the activated carbon-resin composite adsorbent 601 can be achieved by mixing coconut shell activated carbon with a particle size of 1-3 mm with sulfonic acid-type cation exchange resin at a mass ratio of 1:1 to 3:1; or by using polyvinyl acetal to coat the resin onto the surface of the activated carbon to form a core-shell structure. The stainless steel mesh can be made of 304 or 316L material, manufactured by laser cutting or weaving. The edges where the mesh surface connects to the slide rail 602 need to be rolled to enhance structural stability.

[0032] This technical solution enhances the dynamic adsorption capacity for heavy metal ions through the synergistic effect of composite adsorbents. Activated carbon rapidly adsorbs large molecular pollutants, while resin specifically removes ionic heavy metals. A stainless steel mesh maintains the water flow channel while preventing adsorbent loss with the water flow; its 200-300 mesh size achieves a balance between pressure drop and interception efficiency. Compared to single adsorbent materials, this design solves the problems of easy clogging and difficult adsorbent recovery in traditional adsorption beds, while avoiding the drawbacks of low mechanical strength and fragility of pure resin adsorbents.

[0033] The design has been further optimized. The adsorption box 600 contains activated carbon-resin composite adsorbent 601 and stainless steel mesh, with the stainless steel mesh having a mesh size of 200-300.

[0034] As a filter medium, the mesh size of stainless steel mesh directly affects the retention effect and throughput. A 200-300 mesh stainless steel mesh corresponds to a pore size of approximately 250 micrometers. This specification is achieved through the following methods: using 304 or 316L stainless steel, woven in a plain weave to form a standard square hole structure, with a wire diameter ranging from 0.15 to 0.20 mm; alternatively, double-layer twill weaving can be used to improve mechanical strength while maintaining a porosity between 30% and 35%. In practical implementation, the mesh can be welded to the inside of a rectangular frame to form a modular filter sheet, or rolled into a cylindrical shape and nested in the 600mm inlet channel of the adsorption mesh box.

[0035] This technical solution establishes a precise physical retention threshold in the adsorption and separation process by limiting the mesh size of the stainless steel mesh. A 200-300 mesh effectively blocks particulate matter detached from the activated carbon-resin composite adsorbent 601 while avoiding the decrease in flow rate and surge in pressure loss caused by excessively high mesh sizes. Tests show that at this specification, the suspended solids retention rate is increased to over 92%, while the system head loss is controlled within 0.05 MPa, achieving a balance between adsorbent immobilization and hydraulic performance. Compared to conventional metal meshes without a defined mesh size, this solution effectively reduces adsorbent loss due to water flow escape and decreases the frequency of maintenance caused by filter clogging.

[0036] The design was further optimized by using a micro-nano aeration tube 201 with a perforated bottom structure and a high-speed stirrer 202 with a rotation speed of 300-500 rpm.

[0037] The micro / nano aeration tube 201 adopts a bottom-perforated tube structure with a pore size ranging from 0.1 to 0.5 mm and a perforation density of 200-300 per square meter. This structure can generate micro / nano bubbles with a diameter ranging from 50 to 500 nm. The high-speed stirrer 202 is driven by a variable frequency motor with a speed adjustment accuracy of ±10 rpm. The stirring blades are made of 316L stainless steel with a blade inclination angle of 45°. As a preferred embodiment, the aeration tube and the stirrer are arranged coaxially, with the distance between them controlled at 30-50 cm.

[0038] This technical solution generates micro / nano bubbles through a bottom perforated tube structure, combined with a stirring speed of 300-500 rpm, to form a stable gas-liquid mixing system. In one specific embodiment, the micro / nano bubbles increase the gas-liquid contact area, while stirring within a specific speed range avoids both bubble aggregation and breakage of the magnetic ion exchanger 203. As a result, the contact efficiency between heavy metal ions and the exchanger is increased by approximately 40%, and the reaction time is shortened to 60% of that of conventional processes. Compared to conventional aeration and stirring systems, this combined design reduces energy consumption by 15%-20% while maintaining reaction efficiency.

[0039] The design was further optimized by using an electromagnet for the magnetic component 400, with a magnetic field strength ≥0.5T.

[0040] An electromagnet generates a controllable magnetic field by passing an electric current through it, and the magnetic field strength is precisely controlled by adjusting the current. In one specific embodiment, the electromagnet can be implemented in the following ways: using a silicon steel sheet laminated core structure, with the coil wound with corrosion-resistant enameled copper wire and equipped with a water-cooling system; or using a composite structure of rare-earth permanent magnets and an electromagnetic coil, where the permanent magnets provide the basic magnetic field and the electromagnetic coils perform dynamic adjustment. The control system of the electromagnet can be integrated with a PLC module to realize real-time monitoring and automatic adjustment of the magnetic field strength.

[0041] In one specific embodiment, the magnetic separation tank 300 includes a magnetic trapping zone and a filtration zone, separated by an openable and closable partition. A drain valve is installed at the bottom of the adsorption mesh box 600, and periodically collected intercepted material is sent to the concentration unit of the regeneration and recovery module 700 for electrolytic recovery. Further, the magnetic separation tank 300 has a magnetic attraction component 400 at the bottom forming a magnetic trapping zone, and a membrane separation component 500 and an adsorption mesh box 600 at the top forming a filtration zone; the adsorption mesh box 600 can be horizontally moved to the regeneration and recovery module 700 via a slide rail 602. Specifically, as shown... Figure 4 As shown, the magnetic capture process includes: an electromagnet is energized to capture the magnetic ion exchanger 203 at the bottom of the magnetic capture zone; after power is cut off, the partition is opened, and the heavy-duty metal-laden exchanger is moved into the acid / salt regeneration tank 701 via the slide rail 602. The purification process includes: after the partition is closed, the demagnetized water flows upward through the nanofiltration membrane 501 and the adsorption mesh box 600; the stainless steel mesh intercepts residual colloids and free ions, and the intercepted substances are periodically discharged from the drain valve at the bottom of the adsorption mesh box.

[0042] This technical solution solves the problem of low recovery efficiency of magnetic ion exchanger 203 caused by insufficient magnetic field strength in traditional permanent magnets by using a high-strength electromagnet as the magnetic attraction component 400. The magnetic field strength of ≥0.5T ensures sufficient adsorption of nanoscale magnetic materials, while the controllable characteristics of the electromagnet prevent the adsorbent from being lost with the water in traditional processes. In practice, the electromagnet generates a strong magnetic field when energized, causing the magnetic ion exchanger 203 in the water to rapidly aggregate; after power is cut off, the magnetic field disappears, and the adsorbed metal precipitates can be easily removed. This design significantly improves the heavy metal separation efficiency while reducing equipment maintenance frequency. Compared with existing technologies, this solution achieves efficient recovery and reuse of the adsorbent while ensuring separation effectiveness.

[0043] The scheme is further optimized by connecting the acid / salt regeneration tank 701 of the regeneration and recovery module 700 to a 0.5-1.0 mol / L acid / salt solution storage device, which contains a 0.5-1.0 mol / L hydrochloric acid solution or a 10% sodium chloride solution, and the regeneration time is ≤30 minutes.

[0044] In one specific embodiment, the acid / salt regeneration tank 701 is connected in a closed loop to the acid / salt solution storage device via pipelines, wherein the HCl solution concentration range is precisely controlled by a metering pump. As a preferred embodiment, the storage device is made of polyethylene and equipped with a level sensor and an online pH monitor, thereby achieving automated regulation of acid replenishment. Furthermore, the inner wall of the acid / salt regeneration tank 701 is lined with a polytetrafluoroethylene (PTFE) anti-corrosion layer, and a waste gas collection port is provided at the top of the tank, connected to an alkaline spray tower, thus simultaneously addressing the issue of acid mist emission.

[0045] This technical solution addresses the problems of low heavy metal stripping efficiency and unstable acid consumption in traditional processes by optimizing acid concentration and supply methods. Using a medium concentration of hydrochloric acid (0.5-1.0 mol / L) effectively dissolves the heavy metals adsorbed by the magnetic ion exchanger 203 while avoiding the risk of equipment corrosion from strong acids. The closed-loop design increases acid utilization by over 40%, while the online monitoring system ensures the stability of the regeneration process, providing a solution with controllable composition for subsequent electrolytic recovery.

[0046] Further optimization of the scheme: the electrolytic recovery unit 702 adopts titanium-based coated electrodes with a current density of 100-200 A / m. 2 Heavy metal recovery purity ≥ 98%

[0047] Titanium-based coated electrodes are composite electrodes with a titanium metal substrate and a noble metal oxide coating formed on the surface through thermal decomposition or electrodeposition processes. In one specific embodiment, the coating material can be an iridium-based (e.g., IrO2-Ta2O5) or a ruthenium-based (e.g., RuO2-TiO2) oxide, with the coating thickness controlled in the range of 5-20 μm. As a preferred embodiment, the electrode substrate can be processed into a mesh or plate structure, where the mesh structure increases the effective reaction area, and the plate structure facilitates modular installation. The current density is achieved through the coordinated adjustment of the rectifier and the electrode spacing; for example, when the electrode spacing is 10 mm, a constant current mode output current density of 150 A / m² is used.

[0048] This technical solution addresses the problems of rapid electrode corrosion and low heavy metal deposition efficiency in traditional electrolytic recycling by optimizing electrode materials and operating parameters. The titanium-based coated electrode exhibits stable electrochemical performance in a strongly acidic environment. Its high oxygen evolution potential suppresses side reactions, while a specific current density range ensures sufficient reduction and deposition of heavy metal ions while preventing coating peeling due to excessively high local current. Therefore, the regeneration module 700 achieves efficient heavy metal enrichment and long-term stable electrode operation. Compared to conventional graphite electrodes, the metal recovery rate is increased by approximately 30%, and the electrode lifespan is extended to over 3 years.

[0049] The ultraviolet disinfection unit 800 is further optimized and installed at the front end of the drain pipe 801. The ultraviolet disinfection unit 800 uses a low-pressure mercury lamp with a wavelength of 254nm as the ultraviolet light source, with an ultraviolet intensity ≥30mJ / cm². 2 The lamp power is configured from 30-80W according to the water volume to be treated. A quartz sleeve is installed on the outside of the lamp to prevent water from directly contacting the lamp surface. The ultraviolet disinfection unit 800 is connected to the drain pipe 801 via a flange, and a waterproof sealing ring is installed at the connection. A flow sensor is also installed at the front end of the drain pipe 801 to monitor the water flow rate passing through the ultraviolet disinfection unit 800 in real time. The flow data is fed back to the control system to adjust the working power of the ultraviolet lamp.

[0050] In one specific embodiment, the ultraviolet disinfection unit 800 may be equipped with multiple parallel ultraviolet lamps, with a lamp spacing of 5-10 cm, to ensure that the water body can fully receive ultraviolet radiation. As a preferred embodiment, the ultraviolet lamps may be arranged in a ring around the inner wall of the drain pipe 801, so that the water can receive ultraviolet radiation evenly as it flows through. Furthermore, the ultraviolet disinfection unit 800 may be equipped with an automatic cleaning device that periodically removes dirt from the surface of the quartz sleeve using mechanical scraping or chemical cleaning methods to maintain the transmittance of the ultraviolet lamps.

[0051] This technical solution effectively kills residual pathogenic microorganisms in the water by installing an ultraviolet disinfection unit 800 at the front end of the drain pipe 801. Direct irradiation by ultraviolet lamps causes a photochemical reaction in the DNA of microorganisms, disrupting their replication ability and thus achieving disinfection. Compared with traditional chemical disinfection methods, ultraviolet disinfection does not produce harmful byproducts, and the process does not require the addition of chemical agents, avoiding the risk of secondary pollution. Furthermore, the ultraviolet disinfection unit 800 has a compact structure and can be directly integrated into the drain pipe 801 without significantly increasing the equipment size, which is beneficial for modular design.

[0052] The design has been further optimized by installing a buffer water tank 900 between the membrane separation component 500 and the adsorption mesh box 600.

[0053] The buffer tank 900 serves as a transition container and can be made of polyethylene, fiberglass, or stainless steel, with a volume ranging from 0.5 to 3 cubic meters. 3 Preferably at 1.2m 3 A baffle plate can be installed inside the water tank to extend the hydraulic residence time; the recommended tilt angle of the baffle plate is 30-45 degrees. The water tank inlet is connected to the outlet flange of the nanofiltration membrane 501 of the membrane separation assembly 500, and the outlet is connected to the mounting position of the slide rail 602 of the adsorption mesh box 600 via an electric valve. As a preferred embodiment, a liquid level sensor and a pH probe can be installed on the side wall of the water tank, wherein the liquid level sensor is a float type or ultrasonic type, and the pH probe has a measurement range of 0-14. A conical drain outlet with a diameter of not less than 100mm can be provided at the bottom of the water tank.

[0054] This technical solution utilizes a buffer tank 900 to regulate flow and stabilize water quality between the membrane separation and adsorption processes. In one specific embodiment, the permeate from the nanofiltration membrane 501 first enters the buffer tank 900 for temporary storage, thereby eliminating the impact load on the adsorption mesh box 600 caused by the pulsed drainage of the membrane module. The guide plate structure promotes the full diffusion of heavy metal ions, preventing premature saturation of the adsorbent due to excessively high local concentrations. The combined use of a level sensor and a pH probe enables automatic water replenishment and acid-base adjustment; for example, dilute hydrochloric acid is automatically injected when the pH exceeds 8.5. The conical drain outlet facilitates the periodic removal of deposited trace suspended solids, preventing them from entering the adsorption unit and causing blockage. Compared to existing technologies with direct series connection, this design extends the replacement cycle of the adsorption mesh box 600 by more than 40%, while controlling the flux fluctuation of the nanofiltration membrane 501 within ±5%.

[0055] The reducing agent dosing pump 104 of the pretreatment unit 100 is further optimized and connected to the sulfite storage device.

[0056] In one specific embodiment, the sulfite storage device is used to store reducing agents such as sodium sulfite or sodium bisulfite, and quantitative dosing is achieved through a metering pump and a reducing agent dosing pump 104. As a preferred embodiment, the storage device can be equipped with a level sensor and an automatic replenishment system to ensure a continuous supply of reducing agent. Furthermore, the dosing pipeline can be equipped with a one-way valve to prevent wastewater backflow, and a corrosion-resistant polytetrafluoroethylene (PTFE) sealing structure can be used at the dosing port.

[0057] In the treatment of heavy metal wastewater, high-valence heavy metals such as hexavalent chromium must first be reduced to lower-valence states such as trivalent chromium before precipitation can occur. By directly connecting the reducing agent dosing pump 104 to the sulfite storage device, precise and automatic dosing of the reducing agent can be achieved, avoiding dosage errors and operational delays caused by manual dosing. Compared with existing technologies that require temporary preparation of reducing agent solutions, this design significantly improves the efficiency of the reduction reaction, ensuring that heavy metals complete valence conversion during the pretreatment stage, creating favorable conditions for subsequent treatment units. Simultaneously, the closed-loop storage and dosing system effectively prevents the oxidation and deactivation of the reducing agent and secondary pollution.

[0058] like Figure 3As shown, this invention, through the step-by-step coupling of the pretreatment unit 100, reactor module 200, magnetic separation tank 300, and regeneration and recovery module 700, directly forms a continuous and closed heavy metal purification chain within the equipment: alkali solution and sulfite are injected synchronously before entering the reactor, and the pH and valence state of the wastewater are adjusted in milliseconds, avoiding the uneven mixing and reaction lag caused by stepwise addition in traditional processes; the micro-nano aeration pipe 201, which enters the reactor module 200 with the wastewater, operates coaxially with the high-speed stirrer 202 at 300-500 rpm, in... The reaction zone generates uniformly dispersed micro-nano bubbles and maintains the suspended magnetic ion exchanger 203. The ultra-high specific surface area of ​​the bubbles and the shear force of the stirring work together to make the heavy metal ions come into instantaneous contact with the active sites on the surface of the exchanger. The reaction time is reduced to 60% of the original process, and energy consumption is reduced simultaneously. The mixture after the reaction immediately flows into the magnetic separation tank 300. When the electromagnet is energized, it captures the magnetic ion exchanger 203 carrying heavy metals in a directional manner and retains it at the bottom of the magnetic separation tank 300. The retained magnetic exchanger is directly transferred into the acid / salt regeneration tank 701 through the slide rail 602. Simultaneously, the water, after the magnetic particles have been removed, continues to rise and is subjected to dual interception by the nanofiltration membrane 501 and the activated carbon-resin composite adsorption mesh box 600. The 200-300 mesh stainless steel mesh (pore size 50-75μm) ensures both flux and prevents adsorbent loss. The membrane-mesh combination ensures that the heavy metal concentration in the effluent remains consistently below the Class III limit for surface water. In the acid / salt regeneration tank 701, the heavy metals adsorbed by the magnetic ion exchanger 203 are stripped using hydrochloric acid or sodium chloride solution, generating a solution containing a high concentration of heavy metal ions. This solution enters the electrolytic recovery device 702, where heavy metals with a purity ≥98% are deposited and recovered on the surface of the titanium-coated electrode. The electrolyzed acid is returned to the storage device, and the heavy metals are extracted in a high-purity plate form. The system achieves immediate regeneration of the adsorbent and online enrichment of heavy metals. The nanofiltration membrane 501 and the adsorption mesh box 600 primarily intercept residual free ions and colloids in the demagnetized water, preventing them from entering the effluent. The buffer tank 900, located between the membrane module and the adsorption mesh box 600, eliminates the impact of pulsed water flow on the adsorption unit through level and pH interlock control. Simultaneously, it compresses the flux fluctuation of the nanofiltration membrane 501 to within ±5%, significantly extending the replacement cycle of the adsorption mesh box 600. Finally, the ultraviolet disinfection unit 800 physically kills residual pathogenic microorganisms at the front end of the drain pipe 801, eliminating the need for chemical agents and preventing secondary pollution. Structurally, the entire system vertically integrates the four functional units of reaction, separation, recovery, and disinfection in the shortest possible flow, occupying only one-third the area of ​​traditional series processes, while simultaneously achieving multiple benefits such as stable effluent quality, zero adsorbent loss, high-value recovery of heavy metals, and plug-and-play functionality.

[0059] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A heavy metal wastewater treatment device, characterized in that, include: The pretreatment unit (100) includes an alkali addition pump (103) and a reducing agent addition pump (104); The reactor module (200) is connected to the pretreatment unit (100) and is equipped with micro-nano aeration pipes (201), a high-speed stirrer (202) and a magnetic ion exchanger (203). A magnetic separation tank (300) is provided, which includes a magnetic attraction component (400), a membrane separation component (500), and an adsorption mesh box (600); the membrane separation component (500) includes a nanofiltration membrane (501); the adsorption mesh box (600) is detachable and installable. The regeneration module (700) is equipped with an acid / salt regeneration tank (701) and an electrolytic recovery device (702).

2. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The adsorption box (600) contains an activated carbon-resin composite adsorbent (601) and a stainless steel mesh.

3. The heavy metal wastewater treatment equipment according to claim 1 or 2, characterized in that, The magnetic separation tank (300) is equipped with a magnetic suction component (400) at the bottom and a membrane separation component (500) and an adsorption net box (600) at the top; the adsorption net box (600) can be horizontally moved to the regeneration and recycling module (700) via a slide rail (602).

4. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The micro-nano aeration tube (201) has a bottom perforated tube structure, and the high-speed stirrer (202) has a rotation speed of 300-500 rpm.

5. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The magnetic attraction component (400) is an electromagnet with a magnetic field strength ≥0.5T.

6. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The acid / salt regeneration tank (701) of the regeneration and recovery module (700) is connected to the acid / salt solution storage device.

7. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The electrolytic recovery device (702) uses titanium-coated electrodes with a current density of 100-200 A / m. 2 .

8. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, It also includes an ultraviolet disinfection unit (800), which is located at the front end of the drain pipe (801).

9. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, A buffer water tank (900) is provided between the membrane separation component (500) and the adsorption mesh box (600).

10. The heavy metal wastewater treatment equipment according to claim 1, characterized in that, The reducing agent dosing pump (104) of the pretreatment unit (100) is connected to the sulfite storage device.

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