Self-driven monitoring type uranium adsorption and recovery system

Abstract

This invention provides a self-driven monitoring-type uranium adsorption and recovery system, belonging to the field of radioactive wastewater treatment and resource recovery technology. The system uses a proton exchange membrane (MFC) as its basic architecture, separating the anode and cathode chambers. Its core innovation lies in the biomimetic anode in the anode chamber, a three-dimensional porous conductive composite material formed by the self-assembly and freeze-drying of graphene oxide and uranium-reducing microorganisms, possessing both high-efficiency adsorption, biocatalysis, and rapid electron transfer functions. An external circuit monitoring system collects loop current / voltage signals in real time, using current decay as an early warning indicator of adsorption saturation. The uranium recovery unit removes UO2 particles from the biomimetic anode using physical or chemical methods, achieving resource recovery, and the anode is regenerable and reusable. This system integrates adsorption, in-situ reduction, self-driven monitoring, and resource recovery, solving the problems of difficult adsorbent regeneration, lagging monitoring, reliance on external energy, and complex recovery processes in existing technologies.

Description

Technical Field

[0001] This invention belongs to the field of radioactive wastewater treatment and resource recovery technology, and more specifically, it relates to a self-driven monitoring-type uranium adsorption and recovery system. Background Technology

[0002] With the rapid development of the nuclear energy industry, the discharge of uranium-containing radioactive wastewater is increasing daily, making its efficient treatment and pollution control a key issue in ensuring the sustainable development of nuclear energy. Uranium, as a highly toxic and highly mobile radionuclide, poses a serious threat to the ecological environment and human health if directly discharged; simultaneously, as a scarce strategic resource, its resource recovery has significant economic value. Current mainstream uranium-containing wastewater treatment technologies mainly include physicochemical adsorption, biological reduction and fixation, and conventional microbial fuel cells (MFCs), but all have significant technical bottlenecks. (a) Physicochemical adsorption method This method adsorbs uranium by filling an adsorption column with adsorbents such as activated carbon and resin, and relies on offline sampling to detect the uranium concentration at the effluent to determine the adsorption saturation point. Its main drawbacks are: 1. After the adsorbent becomes saturated, it requires desorption and regeneration with high-concentration acids, alkalis, or complexing agents, which is cumbersome, costly, and generates a large amount of secondary waste liquid containing high-concentration uranium, easily causing secondary pollution; 2. The determination of the saturation point has a significant lag; when the effluent concentration exceeds the standard, the adsorption column has already penetrated and failed, resulting in low treatment efficiency; 3. After multiple adsorption-desorption cycles, the adsorption capacity of the adsorbent irreversibly decreases, leading to poor long-term economic efficiency.

[0003] (ii) Biological reduction fixation method This method utilizes a biological carrier loaded with reducing bacteria to drive microorganisms to reduce soluble U(VI) to insoluble UO2 precipitate through the addition of an external organic carbon source. Its core problems are: 1. It requires continuous nutrient addition to maintain microbial activity, resulting in high operating costs, and excessive nutrients can easily lead to eutrophication of the receiving water body, creating secondary environmental risks; 2. It lacks effective real-time monitoring methods, making it impossible to know the microbial activity and uranium reduction process, relying solely on experience to set operating parameters, which can easily lead to insufficient treatment or resource waste, and extremely poor process controllability.

[0004] (III) Conventional Microbial Fuel Cell (MFC) Method This method consists of an anode chamber, a cathode chamber, and a proton exchange membrane. Electric current is generated by the degradation of organic matter by electrogenic bacteria at the anode. It is mainly used for organic matter removal and energy recovery, but has not yet been systematically applied to the entire process of uranium adsorption-reduction-recovery. Its limitations are as follows: 1. The anode uses ordinary carbon felt, carbon cloth and other materials, which have limited adsorption capacity for U(VI) and lack specific adsorption sites; 2. Ordinary electrogenic bacteria enriched at the anode are not highly efficient uranium-reducing bacteria and cannot achieve efficient in-situ stabilization of uranium; 3. The power generation signal only reflects the oxidation rate of organic matter and has a weak correlation with uranium concentration and reduction behavior. It cannot be used as a monitoring indicator and cannot solve the problem of process monitoring.

[0005] In summary, existing technologies generally suffer from problems such as difficulty in adsorbent regeneration, lagging process monitoring, reliance on external energy, and low resource recovery efficiency. There is an urgent need to develop an integrated system that combines efficient adsorption, in-situ reduction, self-driven monitoring, and resource recovery functions to meet the development needs of "environmentally friendly, intelligent, and resource-based" uranium-containing wastewater treatment. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a self-driven monitoring-type uranium adsorption and recovery system, which solves the technical problems of existing uranium-containing radioactive wastewater treatment technologies, such as difficulty in adsorbent regeneration, lag in process monitoring, reliance on external energy drive, and complex resource recovery processes and low recovery rates.

[0007] A self-driven monitoring-type uranium adsorption and recovery system includes a reactor body, an external circuit monitoring system, and a uranium recovery unit; The reactor body is divided into an anode chamber and a cathode chamber by a proton exchange membrane. A biomimetic anode is installed in the anode chamber, and a cathode electrode is installed in the cathode chamber. The external circuit monitoring system connects the bionic anode and cathode electrodes through wires to form a closed loop, in which a load resistor and a data acquisition unit are connected in series. The uranium recovery unit is used to recover uranium from the biomimetic anode that is saturated with adsorption. The biomimetic anode is a three-dimensional porous conductive composite material formed by the self-assembly and freeze-drying of graphene oxide and uranium-reducing microorganisms, which has the functions of efficient adsorption, biocatalysis and rapid electron transfer.

[0008] Preferably, the biomimetic anode comprises a conductive substrate, a three-dimensional graphene oxide network, and uranium-reducing microorganisms; The three-dimensional graphene oxide network is formed on the surface of a conductive substrate through self-assembly technology, and the uranium-reducing microorganisms are uniformly immobilized in the three-dimensional graphene oxide network. The conductive substrate is carbon felt or graphene foam, and the three-dimensional graphene oxide network is a porous, wrinkled nanostructure with -COOH and -OH oxygen-containing functional groups on its surface.

[0009] Preferably, the uranium-reducing microorganism is: Shewanella ShewanellaoneidensisMR-1 Geyperibract Geobacter sulfurreducens Streptococcus mutans Streptococcus mutans or Bacillus subtilis Bacillus subtilis At least one of them.

[0010] Preferably, the cathode electrode is carbon cloth carrying a catalyst, the catalyst is platinum, and the cathode chamber is equipped with an aeration device or an oxidant supply system, using oxygen in the air or dissolved oxygen in an aqueous solution as an electron acceptor.

[0011] Preferably, it also includes a feed and fluid control system, which includes an inlet water pipeline and a nutrient solution storage tank. The inlet water pipeline is connected to the anode chamber for introducing uranium-containing wastewater. The nutrient solution storage tank is connected in parallel or alternately to the inlet water pipeline for replenishing organic substrates.

[0012] Preferably, the data acquisition unit of the external circuit monitoring system is used to monitor and record the current and voltage signals of the closed loop in real time and continuously, and to use the continuous decay of current or voltage as an early warning signal of adsorption saturation.

[0013] Preferably, the triggering condition for the warning signal is that the current or voltage drops to 30%-40% of the initial stable plateau value.

[0014] Preferably, the uranium recovery unit uses physical or chemical methods to remove UO2 particles from the biomimetic anode. The physical method is low-frequency ultrasonic oscillation, and the chemical method is rinsing with dilute nitric acid, acetic acid, sodium citrate solution, or ammonium carbonate solution. After removal, high-purity UO2 products or ammonium diuranate products are obtained by centrifugation, filtration, drying, or crystallization.

[0015] Preferably, the biomimetic anode is prepared by mixing uranium-reducing microbial culture with graphene oxide dispersion, injecting the mixture into a conductive substrate, and then freeze-drying it to form a gel. The graphene oxide dispersion may be modified with amino groups or combined with porous graphene to form a hybrid aerogel.

[0016] Preferably, it also includes a programmable logic controller (PLC), which is electrically connected to the external circuit monitoring system. The preset control logic is: when the real-time current value drops to 40% of the highest stable value and remains there for more than 2 hours, the water inlet valve is automatically shut off and an alarm is activated.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The biomimetic anode designed in this invention organically combines a three-dimensional graphene oxide network with highly efficient uranium-reducing microorganisms. The porous structure of graphene oxide provides a huge specific surface area and abundant oxygen-containing functional groups, achieving highly efficient adsorption of U(VI). Simultaneously, graphene oxide acts as a "nanowire" to promote extracellular electron transfer in microorganisms, working in conjunction with the bioreduction process to form a synergistic "physical adsorption-bioreduction" mechanism. This enables the deep purification of uranium-containing wastewater.

[0018] This invention creatively utilizes the electrogenic characteristics of MFC (Microbial Fusion Cells) to directly correlate the biochemical state of the biomimetic anode with the external circuit current signal. During the adsorption-electrogenic synergistic stage, the system output current maintains a stable plateau value. As the adsorption sites of the biomimetic anode gradually saturate and microbial activity decreases, leading to a reduction in electron transport rate, the current exhibits a sustained and significant decay, and this decay trend occurs much earlier than the increase in uranium concentration in the effluent (breakthrough point). By setting a current threshold, advanced, online, and non-destructive early warning of adsorption saturation can be achieved, completely solving the core problems of traditional technologies that rely on offline detection and monitoring lag. This avoids the discharge of untreated uranium-containing wastewater and improves the reliability and safety of the treatment process.

[0019] This system requires no external energy input. It drives the reduction reaction of uranium by oxidizing natural organic matter in wastewater or by supplementing a small amount of organic substrate (such as sodium acetate and glucose) through microbial oxidation. At the same time, it realizes power generation and monitoring functions, which greatly reduces the energy consumption of operation. Compared with the biological reduction and fixation method, it does not require the continuous addition of a large amount of nutrients, which not only reduces the operating cost, but also avoids the risk of eutrophication of water bodies caused by excessive nutrients, and has stronger environmental compatibility.

[0020] Upon triggering an early warning, this system efficiently removes UO2 particles from the biomimetic anode using gentle physical methods (low-frequency ultrasonic oscillation) or chemical methods (rinsing with dilute nitric acid, sodium citrate, etc.). After solid-liquid separation, drying, or crystallization, high-purity UO2 powder or ammonium diuranate products are obtained, achieving the resource recovery of uranium resources instead of hazardous waste or waste adsorbent requiring disposal generated by traditional technologies, significantly enhancing the economic value of the technology. At the same time, the treated biomimetic anode can be reused after regeneration, forming a "adsorption-recovery-regeneration" cycle process, further reducing operating costs and resource consumption.

[0021] This invention integrates adsorption, in-situ reduction, real-time monitoring, resource recovery, and anode regeneration into a single MFC device. It features a compact structure, simple operation, and eliminates the need for complex equipment combinations. By adjusting the preparation parameters of the biomimetic anode (such as the graphene oxide modification method and the type of microorganism) and operating parameters (such as flow rate and load resistance), it can be adapted to different scenarios, including low, medium, and high concentrations of uranium-containing wastewater (U(VI) concentration 1.5 mg / L-200 mg / L), such as groundwater, industrial wastewater, and waste liquids, making it widely applicable. Attached Figure Description

[0022] Figure 1 This is a flowchart of the system in this invention. Figure 1 ; Figure 2 This is a flowchart of the system in this invention. Figure 2 ; Figure 3 This is a schematic diagram of the system structure in this invention; Figure 4 This is a schematic diagram of the biomimetic anode structure in this invention. Detailed Implementation

[0023] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0024] Please see Figure 1 , Figure 2 and Figure 3 , Figure 1 and Figure 2 The present invention provides a self-driven monitoring-type uranium adsorption and recovery system, comprising a complete system flowchart. This self-driven monitoring-type uranium adsorption and recovery system is designed with functional integration, high efficiency, and stability as its core design principles. The system consists of a reactor body, a biomimetic anode module, a cathode module, an external circuit monitoring system, a feed and fluid control system, a uranium recovery unit, and an optional intelligent control module. The specific selection, structural parameters, and connection methods of each component are as follows: Reactor body: Made of corrosion-resistant and radiation-proof polytetrafluoroethylene (PTFE) or 316L stainless steel, the reactor has a sealed rectangular or cylindrical structure with a total volume that can be designed from 0.5L to 10L (laboratory grade) or 10L to 1000L (industrial grade) depending on the processing scale. The reactor is divided into an anode chamber and a cathode chamber along the central axis by a proton exchange membrane, with a volume ratio of 1:1 to 2:1 to ensure sufficient reaction space on the anode side.

[0025] Proton exchange membrane selection and installation: Use Nafion 117 or Nafion 212 perfluorosulfonic acid proton exchange membranes. The effective area of ​​the membrane should match the area of ​​the anode / cathode electrodes (5cm²-500cm²). The membrane edges are secured to the reactor partition grooves using fluororubber sealing rings to ensure complete isolation between the two chambers, prevent liquid cross-flow, and ensure the optimal concentration of protons (H+). ＋ Efficient migration of ).

[0026] Sealing and safety design: The reactor top cover adopts a flange seal, equipped with a silicone sealing ring and bolt fastening structure to prevent leakage of uranium-containing wastewater and diffusion of radioactive aerosols; exhaust ports are set at the top of the anode chamber and cathode chamber, connected to activated carbon adsorption devices to adsorb radioactive substances or volatile organic compounds that may escape, ensuring safe operation.

[0027] Bionic anode module: The biomimetic anode is a three-dimensional porous conductive composite material, which is the core component for achieving efficient uranium adsorption, in-situ reduction, and electron transfer. Its specific preparation process and structural parameters are as follows: Raw material selection: Conductive substrate: Select carbon felt or graphene foam with a specific surface area ≥300m² / g and porosity ≥85%, cut into sheet-like structures (size 5cm×5cm×0.5cm-50cm×50cm×2cm) that match the cross-section of the anode chamber, as mechanical support and electron collection carrier; before use, it is acid-treated (soaked in 5mol / L HNO3 solution for 24h), washed with water until neutral, and vacuum dried at 60℃ for 12h to remove impurities and activate surface functional groups.

[0028] Graphene oxide (GO): Prepared using a modified Hummers method, with an oxidation degree ≥30% (oxygen-containing functional group content ≥1.5 mmol / g), sheet size of 1-5 μm, and thickness of 0.8-1.2 nm; depending on the application, it can be modified with amino groups (Example 2) or combined with porous graphene (Example 3). Preparation of amino-modified GO: 1g of GO was dispersed in 100mL of deionized water and ultrasonically dispersed for 30min (power 300W, frequency 40kHz). 0.5g of ethylenediamine was added and stirred at 60℃ for 6h. The mixture was centrifuged and washed 3 times (speed 8000r / min, time 10min). After freeze-drying, it was ready for use. Preparation of porous graphene / GO hybrid aerogel: GO dispersion was mixed with porous graphene (mass ratio 1:1), ultrasonically dispersed for 20 min, and 0.1 mol / L hydrochloric acid was added to adjust the pH to 3-4. The mixture was allowed to stand at room temperature for 12 h for self-assembly, and then freeze-dried to form an aerogel with ultra-high porosity (≥90%).

[0029] Uranium-reducing microorganisms: Highly efficient uranium-reducing bacteria, including Shewanella, were selected. ShewanellaoneidensisMR- 1 Geyperibract Geobacter sulfurreducens Streptococcus mutans Streptococcus mutans or Bacillus subtilis Bacillus subtilis One or two of the above, with a strain purity ≥99% and a viable count ≥10. 8 CFU / mL.

[0030] Preparation process: Bacterial culture: The bacterial strain was inoculated into LB medium (formulation: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L NaCl, pH 7.0) or BHI medium (formulation: 10 g / L tryptone, 5 g / L beef extract, 5 g / L yeast extract, 2 g / L glucose, 5 g / L NaCl, 2 g / L disodium hydrogen phosphate, pH 7.3) and cultured with shaking at 30-37℃ and 150-200 rpm for 12-24 h until the OD600 value reached 0.8-1.2, obtaining the logarithmic growth phase bacterial culture. The bacterial cells were collected by centrifugation (6000 rpm, 10 min), washed twice with phosphate-buffered saline (PBS, 0.1 mol / L, pH 7.0), resuspended in deionized water, and lyophilized using a vacuum freeze dryer. Mixing and Self-Assembly: GO dispersion (concentration 10 mg / mL) was mixed with bacterial solution at mass ratios of 2%, 4%, 8%, 16%, and 32%. Dissolved sodium alginate solution was added (ensuring a final concentration of approximately 0.1%), followed by ultrasonic dispersion to form a uniform "GO-bacteria-sodium alginate" composite slurry. The conductive substrate was completely immersed in the composite slurry and vacuum-soaked for 30 minutes (vacuum degree -0.09 MPa) to ensure the dispersion fully penetrated into the substrate pores. Immediately afterward, the formed wet material was immersed in a 0.5%-2% calcium chloride (CaCl2) aqueous solution for several minutes to tens of minutes to allow the sodium alginate to undergo ionic cross-linking, forming a stable gel. The cross-linked gel was removed, gently rinsed with deionized water, and then freeze-dried to obtain the final three-dimensional porous composite material.

[0031] Freeze-drying: The immersed conductive substrate is transferred to a freeze dryer, pre-frozen at -40℃ for 2 hours, and then freeze-dried at -50℃ and vacuum degree ≤10Pa for 24 hours to sublimate the water in the composite dispersion and form a three-dimensional porous biomimetic anode with a stable structure and uniform pores.

[0032] Key performance parameters: The prepared biomimetic anode has a specific surface area ≥600m² / g, porosity ≥88%, conductivity ≥10S / m, microbial immobilization capacity ≥10 mg / cm², and adsorption capacity for U(VI) ≥850mg / g (under the conditions of U(VI) concentration of 50mg / L and pH 6.0).

[0033] Cathode module: Cathode electrode preparation: A carbon cloth with a thickness of 0.2-0.5 mm was selected as the substrate, and a platinum (Pt) catalyst (loading amount 0.5-1 mg / cm²) was loaded onto it. Chloroplatinic acid (H2PtCl6・6H2O) was dissolved in ethanol, and an appropriate amount of Nafion solution was added as a binder. After ultrasonic dispersion for 10 min, the mixture was coated onto the surface of the carbon cloth and dried at 80℃ for 2 h to form a uniform catalyst layer. The size of the cathode electrode was consistent with that of the biomimetic anode to ensure effective connection with the external circuit.

[0034] Auxiliary system configuration: The cathode chamber is equipped with an aeration device or an oxidant supply system. Aeration device: A micro diaphragm pump is selected, with an aeration flow rate of 0.1-1L / min (adjusted according to the reactor volume). The aeration head is made of titanium alloy (pore size 10-20μm) to ensure that oxygen is evenly dispersed in the catholyte as an electron acceptor. Oxidant supply system (suitable for low-oxygen environments): Equipped with a hydrogen peroxide (H2O2) storage tank, the supply rate is controlled by a peristaltic pump (0.1-0.5 mL / min) to maintain the H2O2 concentration in the cathode chamber at 5-10 mmol / L, replacing oxygen as the electron acceptor.

[0035] External circuit monitoring system: Circuit connection: Copper wires are used to connect the bionic anode and cathode electrodes to form a closed loop; a load resistor (resistance value 500Ω-2000Ω, which can be adjusted according to the power generation characteristics) and a data acquisition unit are connected in series in the loop. The connection point between the wire and the electrode is fixed with silver paste and wrapped with a polytetrafluoroethylene insulation layer to prevent corrosion and excessive contact resistance.

[0036] Data acquisition device selection and settings: Select a high-precision data acquisition device with a sampling frequency of 1-10 min / time. It can monitor and record the current (accuracy ±1μA) and voltage (accuracy ±1mV) signals in the circuit in real time. The data acquisition device supports USB or Ethernet connection and can transmit data to a computer or intelligent control module in real time. It also has data storage function (storage capacity ≥10GB).

[0037] Warning signal setting: The preset current / voltage warning threshold is 30%-40% of the initial stable platform value. When the detected signal is continuously lower than the threshold (duration ≥30min), the system automatically triggers an audible and visual alarm (alarm sound intensity ≥80dB, alarm light brightness ≥500cd / m²) and sends a signal to the intelligent control module.

[0038] Feed and fluid control system: Water inlet pipeline: PTFE tubing (inner diameter 4-10mm) is used, connected to the water inlet at the bottom of the anode chamber; the pipeline is equipped with a peristaltic pump (flow accuracy ±0.1mL / min), which can adjust the feed flow rate of uranium-containing wastewater (0.5-10mL / min, laboratory grade) or 10-100L / h (industrial grade); a filter (pore size 1μm) is installed at the water inlet to prevent solid impurities from entering the reactor and clogging the electrodes or proton exchange membrane.

[0039] Nutrient solution storage tank: Use corrosion-resistant polyethylene storage tank (5-50L capacity) to store organic substrate solution (such as sodium acetate concentration 0.5-1mol / L, glucose concentration 1-2mol / L); the storage tank is connected in parallel with the inlet water pipeline through a branch pipe, which is equipped with a solenoid valve and a peristaltic pump. It can automatically switch or replenish organic substrate according to the wastewater quality (COD content ≤50mg / L). The ratio of replenishment flow rate to wastewater inlet flow rate is 1:10-1:20.

[0040] Drainage and return pipelines: A drain pipe is installed at the top of the anode chamber, connecting to the clear water tank or reuse system. A flow meter (accuracy ±1%) and a water quality monitoring probe (capable of real-time detection of U(VI) concentration in the effluent, detection limit ≤0.01mg / L) are installed on the drain pipe. A drain pipe is installed at the bottom of the cathode chamber, which can periodically discharge cathode waste liquid (once every 7-15 days, with a discharge volume of 1 / 3 of the cathode chamber volume), and replenish fresh cathode liquid (0.1mol / L PBS solution, pH 7.0) through the return pipeline.

[0041] Uranium recovery unit: Main structure: It adopts a sealed stainless steel box (volume 10-100L), and is equipped with an electrode fixing frame, cleaning device, and solid-liquid separation device inside. The side of the box is equipped with an observation window (made of lead glass, radiation-proof) and an operating port (with protective gloves) to ensure operation safety.

[0042] Recycling equipment configuration: Physical treatment device: Low-frequency ultrasonic cleaner (frequency 20-40kHz, power 100-500W, treatment tank volume 5-20L), used to remove UO2 particles; Chemical treatment equipment: Corrosion-resistant storage tanks (5-20L capacity) for storing rinsing agents (dilute nitric acid concentration 0.1-0.5mol / L, acetic acid concentration 0.5-1mol / L, sodium citrate concentration 0.1-0.3mol / L or ammonium carbonate concentration 0.3-0.8mol / L), equipped with metering pumps (flow accuracy ±0.1mL / min) to control the rinsing rate; Solid-liquid separation device: high-speed centrifuge (speed 8000-15000r / min, maximum throughput 5-20L), vacuum filter (filter membrane pore size 0.22μm, material is polyvinylidene fluoride); Drying / crystallization equipment: vacuum drying oven (temperature 50-80℃, vacuum degree ≤10Pa), crystallizer (equipped with temperature control system, temperature control accuracy ±1℃).

[0043] Intelligent control module (optional): Select a Siemens S7-200SMART or Mitsubishi FX series programmable logic controller (PLC) for electrical connection with data acquisition units, peristaltic pumps, solenoid valves, alarms, and other equipment. The preset control logic is as follows: Data acquisition: Receives current / voltage signals transmitted by the data acquisition unit in real time and updates the data every 5 minutes; Threshold judgment: When the current value drops to 40% of the highest stable value and remains there for more than 2 hours, a control command is triggered; Operation: Automatically cut off the power to the inlet peristaltic pump and close the inlet pipeline solenoid valve; activate the audible and visual alarm; send SMS or APP notifications to the operator (via GSM or IoT module). Recycling linkage: If equipped with an automated recycling device, the anode chamber opening mechanism and electrode transfer robotic arm can be further controlled to automatically transfer the saturated bionic anode to the recycling unit and start the recycling process.

[0044] System assembly process: Reactor pretreatment: Soak the reactor body, electrode holder, pipeline and other components in 5% nitric acid solution for 12 hours, then rinse with deionized water until neutral, and dry at 60℃ for later use. Proton exchange membrane installation: Lay the proton exchange membrane flat in the slot of the reactor partition, press the fluororubber sealing ring, and tighten the flange with bolts to ensure a leak-free seal; Electrode installation: The prepared biomimetic anode is fixed to the bottom of the anode chamber using a titanium alloy clamp, and the cathode electrode is fixed to the top of the cathode chamber, ensuring that the two electrodes are parallel to the proton exchange membrane and the distance between them is controlled at 1-3 cm. External circuit connection: Connect the bionic anode, load resistor, data acquisition unit and cathode electrode in sequence with copper wire to form a closed loop. Use a multimeter to test the loop resistance (normal range 500-2500Ω) to ensure reliable connection. Auxiliary system installation: Connect the inlet water pipe, nutrient solution storage tank, aeration device, and drain pipe in sequence, and conduct an airtightness test with deionized water (pressure 0.1MPa, maintain for 30 minutes without leakage). Intelligent control module debugging: Connect the data acquisition unit to the PLC, input parameters such as early warning threshold and control logic, and simulate signals to test whether the alarm function and valve switching function are normal. System trial run: Inject deionized water into the anode chamber and 0.1 mol / L PBS solution into the cathode chamber. Start the aeration device and data acquisition device and run for 24 hours to ensure that all components operate stably without leakage or abnormal signals.

[0045] System workflow and operation steps: The workflow of this system is divided into the adsorption-power generation synergy stage, the saturation early warning stage, the resource recovery stage, and the anode regeneration stage. The specific operation steps of each stage are as follows: (I) Adsorption-Electricity Synergistic Stage: Wastewater pretreatment: Based on the water quality characteristics of uranium-containing wastewater, pretreatment is carried out as follows: low-concentration groundwater (COD≥50mg / L, pH6.5-7.5) can be fed directly; medium-concentration industrial wastewater (pH5.0-6.0) needs to be adjusted to pH 6.0-7.0 with 0.1mol / L HCl or NaOH; high-concentration wastewater (U(VI)≥200mg / L) needs to be diluted to U(VI) concentration≤200mg / L to avoid microbial poisoning.

[0046] Feed start-up: Start the peristaltic pump in the inlet pipeline to pump the uranium-containing wastewater into the anode chamber at a set flow rate (0.5-10 mL / min). At the same time, determine whether to add organic substrate based on the COD content of the wastewater: when COD≤50mg / L, start the peristaltic pump in the nutrient solution storage tank and add organic substrate solution in proportion. Cathode operation: Start the aeration device (aeration flow rate 0.1-1L / min) or oxidant supply system in the cathode chamber to maintain the dissolved oxygen concentration in the cathode chamber ≥5mg / L or the H2O2 concentration 5-10mmol / L; Process monitoring: The data acquisition unit records current / voltage signals in real time. In the initial stage (1-3 days), the signals gradually rise to a stable plateau value (current density 180-220 mA / m², voltage 0.4-0.5 V). At this time, the three-dimensional network of graphene oxide in the biomimetic anode adsorbs U(VI), and microorganisms oxidize organic substrates to produce electrons and protons. Proton (H) ＋ It migrates through the proton exchange membrane to the cathode chamber; Electrons travel through two paths: ① Direct bioreduction pathway: Microorganisms directly reduce adsorbed U(VI) to UO2; ②Electrode reduction path: Electrons flow to the cathode via the graphene oxide network, conductive substrate, and external circuit, indirectly reducing U(VI); Clear water discharge: The treated clear water discharged from the anode chamber is tested by a water quality monitoring probe. When the U(VI) concentration is ≤0.05mg / L, it is discharged into the clear water tank for reuse or discharged in compliance with standards; if the concentration exceeds the standard, the water is returned to the feed end for reprocessing.

[0047] (II) Saturation warning stage: Signal monitoring: The data acquisition unit continuously monitors the current / voltage signal. As the running time increases, the adsorption sites of the biomimetic anode are gradually occupied by U(VI) and UO2, resulting in decreased microbial activity, reduced electron transfer rate, and gradual signal attenuation. Threshold judgment: When the current value is continuously lower than 30%-40% of the initial stable platform value (duration ≥30min), the system automatically triggers an audible and visual alarm, and the PLC records the warning time, prompting the system to enter the recovery phase; System shutdown: After receiving the warning signal, the operator shall shut down the peristaltic pump of the inlet water pipeline and the nutrient solution storage tank, stop feeding and organic substrate replenishment; shut down the aeration device or oxidant supply system of the cathode chamber.

[0048] (III) Resource recycling stage: Anode removal: Open the top cover of the anode chamber, wear radiation-proof gloves and a mask, remove the adsorption-saturated bionic anode from the reactor, and transfer it to the electrode holder of the uranium recovery unit; Recycling method selection: Physical recovery (suitable for medium-concentration wastewater treatment): Inject deionized water into the treatment tank of the recovery unit to submerge the bionic anode, start the low-frequency ultrasonic cleaner (power 300W, frequency 40kHz), and treat for 10-15 minutes to peel UO2 particles off the anode surface. Chemical recovery (suitable for low / high concentration wastewater treatment): Select the eluent according to the product requirements: When recovering UO2 powder, use 0.1 mol / L sodium citrate solution for rinsing (rinsing rate 1 mL / min, rinsing time 30 min); when recovering ammonium diuranate, use 0.5 mol / L ammonium carbonate solution for rinsing (rinsing rate 2 mL / min, rinsing time 60 min) to form uranyl carbonate complex; Solid-liquid separation: Transfer the stripped suspension or eluent to a high-speed centrifuge and centrifuge at 8000-15000 r / min for 10-20 min, and collect the precipitate; if there are still suspended particles in the supernatant, filter it through a vacuum filter (0.22μm filter membrane); Product purification: UO2 powder: The precipitate was transferred to a vacuum drying oven and dried at 60°C for 12 hours to obtain black UO2 powder (purity ≥95%), which was then sealed and stored in a radiation-proof container. Ammonium diuranate: The ammonium carbonate eluent is transferred to a crystallizer, heated to 80°C for evaporation and concentration, cooled to room temperature for crystallization, filtered, and dried at 80°C for 6 hours to obtain a high-purity ammonium diuranate product (purity ≥98%).

[0049] (iv) Anode regeneration stage: Anode cleaning: The recycled bionic anode is placed in a cleaning tank and ultrasonically cleaned with deionized water for 10 minutes (power 200W) to remove residual UO2 particles and impurities on the surface; Microbial remediation: If the microbial activity on the anode decreases, immerse the anode in fresh bacterial solution (concentration 10). 8 In a solution of CFU / mL, the microorganisms were added and fixed by static incubation at 30°C for 12 hours. Performance testing: The regenerated bionic anode was placed in the test reactor and the adsorption capacity was tested (U(VI) concentration 50mg / L, pH 6.0). When the adsorption capacity was ≥700mg / g (more than 82% of the initial capacity), the regeneration was deemed qualified. Reuse: Reinstall the qualified regenerated anode into the reactor, close the top cover, start the feeding system, and enter the next adsorption-electricity generation cycle; if the adsorption capacity is <700mg / g, replace it with a newly prepared biomimetic anode.

[0050] Example 1: Treatment of low-concentration uranium-containing groundwater (U(VI) concentration 1.5 mg / L) System Configuration: Reactor: 0.5L volume, anode / cathode chamber volume ratio 1:1, proton exchange membrane is Nafion 117, effective area 5cm²; Bionic anode: The conductive substrate is carbon felt (5cm×5cm×0.5cm), and the microorganisms are... ShewanellaoneidensisMR-1 GO unmodified, after preparation, the specific surface area is 650 m² / g, and the microbial fixation capacity is 20 mg / cm²; Cathode: Carbon cloth electrode with a platinum loading of 0.5 mg / cm², aeration flow rate of 0.1 L / min; External circuit: load resistance 1000Ω, data acquisition frequency 10min / time; Operating parameters: Feed flow rate: 5 mL / min, no need to add organic substrate (utilizing the natural COD of groundwater ≈ 50 mg / L); Operating time: 30 days, initial stable voltage: 0.45V; Recycling process: Warning Trigger: After 30 days of operation, the voltage drops to 0.15V (33.3% of the initial value), triggering an alarm. Rinsing agent: 0.1 mol / L sodium citrate solution, rinsing rate: 0.5 mL / min, rinsing time: 30 min; Product: UO2 powder, yield approximately 0.225g, purity 98.2%, uranium removal rate 98.5%; Anode regeneration: Ultrasonic cleaning with deionized water for 10 minutes, no need to replenish microorganisms, the adsorption capacity after regeneration is 780mg / g, and the adsorption capacity is still ≥700mg / g after repeated use 5 times.

[0051] Example 2: Treatment of medium-concentration uranium-containing industrial wastewater (U(VI) concentration 50 mg / L) System Configuration: Reactor: 2L volume, anode / cathode volume ratio 2:1, proton exchange membrane is Nafion 212, effective area 20cm²; Bionic anode: The conductive substrate is carbon felt (10cm×10cm×0.5cm), and the microorganisms are... Streptococcus mutans After amino modification, GO was prepared with a specific surface area of ​​720 m² / g and a microbial fixation capacity of 25 mg / cm². Cathode: Carbon cloth electrode with a platinum loading of 1 mg / cm², aeration flow rate of 0.5 L / min; External circuit: load resistance 500Ω, data acquisition unit sampling frequency 5min / time; Operating parameters: Wastewater pretreatment: Adjust pH to 6.0 with 0.1 mol / L NaOH, COD≈500 mg / L (containing sodium acetate), no organic substrate replenishment required; Feed flow rate: 20 mL / min, hydraulic retention time: 12 h; Operating time: 7 days, initial stable current density: 180 mA / m²; Recycling process: Warning Trigger: After 7 days of operation, the current density drops to 60mA / m² (33.3% of the initial value), triggering an alarm; Physical treatment: Ultrasonic power 300W, frequency 40kHz, treatment time 10min; Product: UO2 powder, yield approximately 9.92g, purity 98.8%, uranium removal rate 99.2%; Anode regeneration: Ultrasonic cleaning with deionized water for 15 min, followed by soaking in bacterial solution for 6 h. After regeneration, the adsorption capacity is 800 mg / g. After repeated use 4 times, the adsorption capacity is still ≥750 mg / g.

[0052] Example 3: Treatment of high-concentration uranium-containing wastewater and its integration with an intelligent control system (U(VI) concentration 200 mg / L) System Configuration: Reactor: 5L volume, anode / cathode volume ratio 2:1, proton exchange membrane is Nafion117, effective area 50cm²; Bionic anode: The conductive substrate is a porous graphene / GO hybrid aerogel (15cm×15cm×1cm), and the microorganisms are... Bacillus subtilis After preparation, the specific surface area was 850 m² / g, and the microbial fixation amount was 40 mg / cm². Cathode: Carbon cloth electrode with a platinum loading of 1 mg / cm², aeration flow rate of 1 L / min; External circuit: load resistance 800Ω, data acquisition frequency 1min / time, intelligent control module is Siemens S7-200SMARTPLC; Operating parameters: Wastewater pretreatment: dilute to a U(VI) concentration of 200 mg / L, adjust the pH to 6.5 with 0.1 mol / L HCl, and add glucose to a concentration of 1000 mg / L; Feed flow rate: 50 mL / min, hydraulic retention time: 8 h; Running time: 48 hours, initial steady-state current density: 220 mA / m²; Recycling process: Warning Trigger: After 48 hours of operation, the current density drops to 88mA / m² (40% of the initial value), and continues for 2.5 hours. The PLC then automatically shuts off the inlet valve and triggers an alarm. Chemical treatment: 0.5 mol / L ammonium carbonate solution, rinsing rate 5 mL / min, rinsing time 60 min; Product: Ammonium diuranate crystals, yield approximately 35.6g, purity 99.0%, uranium removal rate 99.5%; Anode regeneration: Rinse with 0.1 mol / L hydrochloric acid for 5 min, rinse with deionized water until neutral, replenish with bacterial solution and soak for 12 h. After regeneration, the adsorption capacity is 820 mg / g. After repeated use 3 times, the adsorption capacity is still ≥780 mg / g.

[0053] System maintenance and security precautions: Routine maintenance: Check the system's operating status daily, and record current / voltage data, inlet and outlet water flow rates, and water quality parameters to ensure data continuity. Clean the inlet water pipe filter once a week to prevent clogging; change the catholyte every 15 days to maintain the efficiency of the cathodic reaction. The data acquisition unit and water quality monitoring probe are calibrated monthly to ensure monitoring accuracy. Safety precautions: When handling uranium-containing wastewater and biomimetic anodes, radiation-proof gloves, masks, and protective clothing must be worn to avoid direct contact. During reactor operation, the top cover must not be opened to prevent leakage of radioactive materials; The operation of the uranium recovery unit must be carried out in a fume hood, and the leaching agent and uranium-containing waste liquid must be collected separately and handed over to a professional organization for treatment; Troubleshooting: If the current / voltage signal is abnormally low, check whether the electrode connection is loose or whether the proton exchange membrane is contaminated. Replace the proton exchange membrane if necessary. If the concentration of U(VI) in the effluent exceeds the standard in advance, it may be due to a decrease in the activity of the bionic anode, and the recovery process needs to be started in advance. If a leak occurs, immediately stop the system, disconnect the power supply, absorb the leaked liquid with absorbent cotton, and conduct radiation detection and treatment.

[0054] This detailed embodiment elaborates on the system's component selection, preparation process, assembly steps, workflow, and application examples, covering all the technical features of the claims. It ensures that those skilled in the art can accurately reproduce the invention according to the description, achieving efficient treatment, real-time monitoring, and resource recovery of uranium-containing wastewater.

[0055] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A self-driven monitoring-type uranium adsorption and recovery system, characterized in that: Includes the reactor body, external circuit monitoring system, and uranium recovery unit; The reactor body is divided into an anode chamber and a cathode chamber by a proton exchange membrane. A biomimetic anode is installed in the anode chamber, and a cathode electrode is installed in the cathode chamber. The external circuit monitoring system connects the bionic anode and cathode electrodes through wires to form a closed loop, in which a load resistor and a data acquisition unit are connected in series. The uranium recovery unit is used to recover uranium from the biomimetic anode that is saturated with adsorption. The biomimetic anode is a three-dimensional porous conductive composite material formed by the self-assembly and freeze-drying of graphene oxide and uranium-reducing microorganisms, which has the functions of efficient adsorption, biocatalysis and rapid electron transfer.

2. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, The biomimetic anode comprises a conductive substrate, a three-dimensional graphene oxide network, and uranium-reducing microorganisms; The three-dimensional graphene oxide network is formed on the surface of a conductive substrate through self-assembly technology, and the uranium-reducing microorganisms are uniformly immobilized in the three-dimensional graphene oxide network. The conductive substrate is carbon felt or graphene foam, and the three-dimensional graphene oxide network is a porous, wrinkled nanostructure with -COOH and -OH oxygen-containing functional groups on its surface.

3. The self-driven monitoring-type uranium adsorption and recovery system according to claim 2, characterized in that, The uranium-reducing microorganism is Shewanella. ShewanellaoneidensisMR-1 Geyperibract Geobacter sulfurreducens Streptococcus mutans Streptococcus mutans or Bacillus subtilis Bacillus subtilis At least one of them.

4. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, The cathode electrode is carbon cloth loaded with a catalyst, the catalyst is platinum, and the cathode chamber is equipped with an aeration device or an oxidant supply system, using oxygen in the air or dissolved oxygen in an aqueous solution as an electron acceptor.

5. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, It also includes a feed and fluid control system, which includes an inlet water pipeline and a nutrient solution storage tank. The inlet water pipeline is connected to the anode chamber for introducing uranium-containing wastewater. The nutrient solution storage tank is connected in parallel or alternately to the inlet water pipeline for replenishing organic substrates.

6. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, The data acquisition unit of the external circuit monitoring system is used to monitor and record the current and voltage signals of the closed loop in real time and continuously, and to use the continuous decay of current or voltage as an early warning signal of adsorption saturation.

7. The self-driven monitoring-type uranium adsorption and recovery system according to claim 6, characterized in that, The warning signal is triggered when the current or voltage drops to 30%-40% of the initial stable plateau value.

8. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, The uranium recovery unit uses physical or chemical methods to remove UO2 particles from the biomimetic anode. The physical method is low-frequency ultrasonic oscillation, and the chemical method is rinsing with dilute nitric acid, acetic acid, sodium citrate solution, or ammonium carbonate solution. After removal, high-purity UO2 products or ammonium diuranate products are obtained by centrifugation, filtration, drying, or crystallization.

9. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, The biomimetic anode is prepared by mixing uranium-reducing microbial bacterial solution with graphene oxide dispersion, injecting the mixture into a conductive substrate, and then freeze-drying it to form a gel. The graphene oxide dispersion can be modified with amino groups or combined with porous graphene to form a hybrid aerogel.

10. The self-driven monitoring-type uranium adsorption and recovery system according to claim 1, characterized in that, It also includes a programmable logic controller (PLC), which is electrically connected to the external circuit monitoring system. The preset control logic is: when the real-time current value drops to 40% of the highest stable value and remains there for more than 2 hours, the water inlet valve is automatically shut off and an alarm is triggered.

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