High-flux cellulose immobilized tannin membrane adsorption material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of radioactive wastewater treatment and uranium extraction from seawater, and discloses a high-flux cellulose immobilized tannin membrane adsorption material as well as a preparation method and application thereof. The membrane adsorption material comprises an aldehyde cellulose acetate microfiltration membrane and waxberry tannin which is cured on the microfiltration membrane through gradient cross-linking. The membrane adsorption material provided by the invention keeps a reticular porous structure of a cellulose microporous filter membrane and has the characteristics of high flux and rapid mass transfer, the pure water flux of a single-layer membrane can reach 300 L / (m.h), the treatment capacity of a multi-layer membrane is remarkably increased, large-flow treatment can be realized, and the efficiency of extracting uranium from seawater or uranium-containing wastewater is remarkably improved.

Description

Technical Field

[0001] This invention relates to the fields of radioactive wastewater treatment and seawater uranium extraction technology, specifically to a high-throughput cellulose-cured tannin membrane adsorption material, its preparation method, and its application. Background Technology

[0002] Uranium resources are a key raw material for nuclear energy development. Land-based uranium reserves are limited and unevenly distributed (global land-based uranium reserves are only sufficient for approximately 90 years of mining). While the concentration of uranium in seawater is low (approximately 3.3 μg / L), its total reserves are as high as 4.5 billion tons, more than 1000 times that of land-based reserves. Therefore, developing efficient seawater uranium extraction technology is of great strategic significance for ensuring national energy security.

[0003] Currently, uranium extraction from seawater faces the following challenges: traditional particulate adsorbents (such as resins and MOFs) exhibit high bed pressure drops during dynamic adsorption, resulting in throughputs generally below 50 L / (m²·h); existing membrane adsorption materials (such as polyamide composite membranes) have relatively high throughputs, but their uranium adsorption capacity is less than 0.1 mmol / g; and seawater uranium extraction requires the treatment of extremely large volumes of water (3 × 10⁻⁶ mmol / g per ton of uranium). 8 High-throughput materials (such as seawater) are key to industrialization.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems and provides a high-throughput cellulose-cured tannin membrane adsorbent material, its preparation method and application. The adsorbent material has a high adsorption capacity for uranium and a weak flux decay during continuous operation.

[0006] To achieve the above objectives, the first technical solution provided by this invention is as follows: A high-flux cellulose-cured tannin membrane adsorption material comprises an aldehyde-modified cellulose acetate microporous filter membrane and bayberry tannin cured on the microporous filter membrane by gradient crosslinking.

[0007] Preferably, the loading of bayberry tannin is ≥400 mg / g.

[0008] Preferably, the dynamic pure water flux of the adsorbent material is ≥300 L / (m²·h), and the dynamic adsorption capacity for 0.05 mmol / L UO2²⁺ solution is ≥0.45 mmol / g.

[0009] Preferably, the aldehyde-modified cellulose acetate microporous filter membrane is obtained by selectively oxidizing the hydroxyl groups of the cellulose acetate microporous filter membrane with sodium periodate to form aldehyde groups.

[0010] The second technical solution adopted in this invention is: A method for preparing high-flux cellulose-cured tannin membrane adsorbent materials includes: Cellulose acetate microporous membranes were immersed in a solution containing sodium periodate and sodium chloride, and the reaction was terminated after being exposed to light at 50°C for 4–8 hours. The membranes were then washed to obtain aldehyde-modified cellulose acetate microporous membranes. Aldehyde-modified cellulose acetate microporous membranes were pre-crosslinked with myricetin in low concentration glutaraldehyde at 50–55℃ and pH 7.5–8.0 for 2–3 h. Supplement with glutaraldehyde and cure and crosslink at high concentrations of glutaraldehyde, 65–70℃, and pH 7.5–8.0 for 5–6 hours; The adsorbent material is obtained after washing and drying.

[0011] Preferably, during the pre-crosslinking stage, the glutaraldehyde concentration is 5–8 wt%.

[0012] Preferably, during the curing and crosslinking stage, the glutaraldehyde concentration is 10–15 wt%.

[0013] Preferably, the reaction is terminated with ethylene glycol after reacting at 50°C in the dark for 4–8 hours.

[0014] The third technical solution adopted in this invention is: Application of high-throughput cellulose-cured tannin membrane adsorbents in the continuous extraction of uranium from seawater or uranium-containing wastewater.

[0015] Preferably, the adsorbent material is a dynamic filtration adsorption membrane configured in the membrane module of a multi-stage tandem uranium extraction system. Under the conditions of feed uranium concentration of 0.03–0.3 μg / L and flow rate of 10–50 mL / min, the single-stage membrane achieves a single-stage rejection rate of ≥95% for UO2²⁺, and after elution with 0.1 mol / L HNO3, the adsorption capacity recovery rate is ≥98%, and it can be recycled ≥20 times.

[0016] refer to Figure 1 A schematic diagram of the stacked structure of a high-throughput cellulose-cured tannin membrane adsorbent material, and Figure 2 A schematic diagram of the dynamic adsorption device flow chart shows that the uranium extraction system has ≥3 stages of membrane modules, which are detachable membrane modules connected in series; each stage has an independent constant flow pump with a flow rate according to V. n =V1×0.85ⁿ⁻¹ decreasing (Example: Stage 1 50 mL / min → Stage 3 36 mL / min); Processing capacity: Natural seawater (U 3.3 μg / L, pH 8.1) continuously operating for 30 days, the overall system processing capacity is ≥5 m³ / (m²·d), and the U concentration at the final stage outlet is <0.1 μg / L.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The membrane adsorption material provided by this invention maintains the network porous structure of cellulose microporous filter membrane, and has the characteristics of high flux and rapid mass transfer. The pure water flux of a single-layer membrane can reach 300 L / (m²·h), while the treatment capacity of a multi-layer membrane is significantly increased, enabling large flow rate treatment and significantly improving the efficiency of uranium extraction from seawater or uranium-containing wastewater.

[0018] The membrane adsorption material provided by this invention has a static water contact angle of 70–95°, which ensures that the membrane surface is moderately hydrophilic, which is conducive to rapid water phase permeation and inhibits non-specific adsorption of proteins, etc. Its pore size distribution is 0.5–2 μm, which can maintain high permeability while avoiding tannin loss.

[0019] The membrane adsorption material provided by this invention has a high affinity for UO2. 2+ The maximum adsorption capacity can reach 0.5137 mmol / g (at 323 K). In mixed solutions containing multiple coexisting ions, this membrane adsorbent material exhibits high adsorption capacity for UO2. 2+ The adsorption capacity of this membrane is significantly higher than that of other ions, exhibiting high selectivity. After adsorption saturation, dynamic elution with 0.1 mol / L HNO3 (flow rate 10 mL / min, 30 min) resulted in a uranium desorption rate ≥98%. After 20 adsorption-desorption cycles, the dynamic adsorption capacity retention rate was ≥95%. After being placed in natural seawater for 30 days, the membrane's surface morphology showed no significant change, and it still possessed a high adsorption capacity, demonstrating excellent antifouling properties.

[0020] The cellulose acetate microporous filter membrane and bayberry tannin used in this invention are both widely available and inexpensive natural biomass materials, resulting in low preparation costs. The entire preparation process is simple, does not involve complex chemical reactions or the emission of harmful substances, and is environmentally friendly. Attached Figure Description

[0021] Figure 1 A schematic diagram of the stacked structure of a high-throughput cellulose-cured tannin membrane adsorbent material (showing a multi-layer cascaded enlarged design). Figure 2 This is a flow chart of a dynamic adsorption device (including a constant flow pump, membrane stack module, and online monitoring unit). Figure 3 This is a water flux experimental setup; Figure 4 The FTIR spectra of CA and BT-CA in Example 1 are shown below. Figure 5 The pure water flux of CA and BT-CA in Example 4; Figure 6 The figure shows the test results of the continuous adsorption separation experiment of the BT-CA membrane in Example 3. Detailed Implementation

[0022] The following embodiments are provided to specifically describe the present invention. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the scope of protection of the present invention.

[0023] In the following examples, the high-flux cellulose-cured tannin membrane adsorbent material is referred to as BT-CA membrane, and the relevant performance testing methods used are as follows: 1. The tannin loading was determined by weighing. Before weighing, the sample was dried in an oven at 45℃ for 1 hour. The formula for calculating the loading is: Loading capacity = (W1-W0) / W0, where W0 is the mass of the membrane before tannin curing (mg); W1 is the mass of the membrane after tannin curing (mg); the loading capacity is expressed as mg (tannin) / g (membrane).

[0024] 2. Seawater Adsorption Performance Test: The prepared BT-CA membrane was placed in a membrane filtration device (4 layers). Seawater was continuously pumped in using a constant flow pump at a feed rate of 20 mL / min. After 30 days, the BT-CA membrane was removed and eluted with a 0.1 mol / L HNO3 solution. The UO2 in the eluent was determined using inductively coupled plasma atomic emission spectrometry (ICP-AES). 2+ The concentration was determined, and the actual seawater adsorption capacity of BT-CA was calculated using Equation 1, in mg UO2. 2+ / g (adsorbent) means: Formula 1 In the formula, C e UO2 in the eluent 2+ Concentration (mg / L); q e denoted as adsorption capacity (mg / g); V is the volume of the eluent (L); m is the mass of the adsorbent (g).

[0025] 3. Pure water flux test: The test apparatus for measuring the pure water flux of the membrane is as follows: Figure 3 As shown. The experiment used a reusable needle-type membrane filter as the filtration device, employing terminal filtration. A constant volume water column was used as the driving force, and deionized water was used as the test water. The constant flow pump was adjusted to ensure a constant water column height. The outflow rate Q of the needle-type membrane filter was recorded over a certain period, and the effective filtration area A of the membrane was calculated. The pure water flux J of the cellulose acetate membrane and the cellulose-cured tannin membrane under this pressure was calculated according to Equation 2. W : Equation 2, In the formula: J W Pure water flux (L / (m)) 2·h), Q is the flow rate (L), and A is the membrane area (m²). 2 ).

[0026] 4. Antifouling resistance: After immersing BT-CA in seawater for 30 days, its pure water flux J was tested using the method described above. W Flux retention rate = J W ˊ / J W ×100%.

[0027] 5. Continuous Adsorption Separation Experiment: A 5.0 cm diameter BT-CA membrane was fixed on a sieve plate. This membrane filtration system can be configured with a single membrane or multiple membranes. A constant flow pump was used for continuous feeding while maintaining a constant liquid level. The effect of the cellulose-fixed tannin membrane BT-CA on UO2 was determined according to the terminal filtration method. 2+ The adsorption and separation characteristics of UO2. 2+ The initial concentration is denoted as C0. The effluent is collected at regular flow rates, and the UO2 is analyzed. 2+ The concentration, denoted as C e With the flow rate per unit area as the x-axis, C e Plot the penetration curve with / C0 as the ordinate. e When C0 > 0.05, the first point is the breakthrough point. After adsorption, elution was performed with a 0.1 mol / L HNO3 solution, and the UO2 in the eluent was analyzed. 2+ The concentration was determined, and an elution curve was plotted.

[0028] Example 1: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: A cellulose acetate microporous membrane (CA, average pore size 0.82 μm, initial contact angle 78°) was immersed in an aqueous solution containing 0.2 mol / L NaIO4 and 0.24 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain the aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 6 wt% glutaraldehyde and pH 7.8, and 16 g of myricetin was added. The reaction was carried out at 52 ℃ for 2.5 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 12 wt%, and the temperature was raised to 68 ℃ to continue the reaction for 5.5 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60°C to obtain the BT-CA membrane.

[0029] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 81.3°, pore size distribution peak 0.63 μm; tannin loading: 502 mg / g; pure water flux: 306 L / (m²·h); seawater uranium extraction (3.3 μg / LU): adsorption capacity 8.3±0.2 mg / g (30 days); antifouling: flux retention rate 86% after 30 days of seawater immersion.

[0030] The FTIR spectra of the CA and BT-CA films in this embodiment are as follows: Figure 1 As shown.

[0031] Example 2: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: A cellulose acetate microporous membrane (CA, average pore size 0.82 μm, initial contact angle 78°) was immersed in an aqueous solution containing 0.3 mol / L NaIO4 and 0.16 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain the aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: Place the aldehyde-modified membrane in 100 mL of phosphate buffer containing 5 wt% glutaraldehyde and pH 7.8, add 10 g of myricetin, and react at 50 ℃ for 2.5 h; Curing crosslinking: Add glutaraldehyde to 10 wt%, raise the temperature to 65 ℃ and continue the reaction for 5.5 h, maintaining pH 7.8 throughout the process; After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0032] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 76.5°, pore size distribution peak 0.76 μm; tannin loading: 450 mg / g; pure water flux: 321 L / (m²·h); seawater uranium extraction: adsorption capacity 7.5±0.3 mg / g; antifouling: flux retention rate 88%.

[0033] Example 3: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: Cellulose acetate microporous membrane was immersed in an aqueous solution containing 0.4 mol / L NaIO4 and 0.35 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain an aldehyde-modified membrane with an aldehyde density of 3.4 mmol / g. Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 7 wt% glutaraldehyde and pH 7.8, and 20 g of myricetin was added. The reaction was carried out at 50 ℃ for 2.5 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 15 wt%, and the temperature was raised to 70 ℃ to continue the reaction for 6.0 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0034] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 92.5°, pore size distribution peak 0.51 μm; tannin loading: 552 mg / g; pure water flux: 286 L / (m²·h); seawater uranium extraction: adsorption capacity 8.6±0.1 mg / g; antifouling: flux retention rate 86%.

[0035] The breakthrough curve corresponding to the continuous adsorption separation experiment of the BT-CA membrane in this embodiment is as follows: Figure 6 As shown.

[0036] Example 4: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: Cellulose acetate microporous membrane was immersed in an aqueous solution containing 0.3 mol / L NaIO4 and 0.21 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 5 wt% glutaraldehyde and pH 7.8, and 12 g of myricetin was added. The reaction was carried out at 50 ℃ for 2.0 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 12 wt%, and the temperature was raised to 65 ℃ to continue the reaction for 5 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0037] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 79.8°, pore size distribution peak 0.71 μm; tannin loading: 476 mg / g; pure water flux: 312 L / (m²·h); seawater uranium extraction (pH=6.5): adsorption capacity 8.1±0.2 mg / g; antifouling: flux retention 91%.

[0038] In this embodiment, the pure water flux of CA and BT-CA membranes at different numbers of layers is compared as follows: Figure 5 As shown.

[0039] Example 5: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: Cellulose acetate microporous membrane was immersed in an aqueous solution containing 0.4 mol / L NaIO4 and 0.28 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 7 wt% glutaraldehyde and pH 7.8, and 18 g of myricetin was added. The reaction was carried out at 53 ℃ for 2.5 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 13 wt%, and the temperature was raised to 68 ℃ to continue the reaction for 5 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0040] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 83.4°, pore size distribution peak 0.54 μm; total tannin loading: 523 mg / g; pure water flux: 290 L / (m²·h); seawater uranium extraction (pH=6.5): adsorption capacity 7.6±0.3 mg / g; antifouling: flux retention rate 93%.

[0041] Example 6: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: Cellulose acetate microporous membrane was immersed in an aqueous solution containing 0.20 mol / L NaIO4 and 0.23 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: Place the aldehyde-modified membrane in 100 mL of phosphate buffer containing 6 wt% glutaraldehyde and pH 7.8, add 15 g of myricetin, and react at 50 ℃ for 2.5 h; Curing crosslinking: Add glutaraldehyde to 12 wt%, raise the temperature to 68 ℃ and continue the reaction for 5 h, maintaining pH 7.8 throughout the process; After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0042] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 81.5°, pore size distribution peak 0.64 μm; tannin loading: 490 mg / g; pure water flux: 308 L / (m²·h); seawater uranium extraction (pH=6.5): adsorption capacity 7.3±0.2 mg / g; antifouling: flux retention 92%.

[0043] Example 7 Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: A cellulose acetate microporous filter membrane was immersed in an aqueous solution containing 0.30 mol / L NaIO4 and 0.28 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain an aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 7 wt% glutaraldehyde and pH 7.8, and 17 g of myricetin was added. The reaction was carried out at 52 ℃ for 2.5 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 14 wt%, and the temperature was raised to 65 ℃ to continue the reaction for 5 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0044] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 81.9°, pore size distribution peak 0.56 μm; tannin loading: 511 mg / g; pure water flux: 296 L / (m²·h); seawater uranium extraction: adsorption capacity 7.7±0.1 mg / g; antifouling: flux retention 90%.

[0045] Example 8: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: A cellulose acetate microporous filter membrane was immersed in an aqueous solution containing 0.20 mol / L NaIO4 and 0.18 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain an aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: Place the aldehyde-modified membrane in 100 mL of phosphate buffer containing 5 wt% glutaraldehyde and pH 7.8, add 15 g of myricetin, and react at 50 ℃ for 2.0 h; Curing crosslinking: Add glutaraldehyde to 10 wt%, raise the temperature to 65 ℃ and continue the reaction for 5 h, maintaining pH 7.8 throughout the process; After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0046] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 79.5°, pore size distribution peak 0.67 μm; tannin loading: 468 mg / g; pure water flux: 313 L / (m²·h); seawater uranium extraction: adsorption capacity 7.4±0.3 mg / g; antifouling: flux retention 90%.

[0047] Example 9: Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: Cellulose acetate microporous membrane was immersed in an aqueous solution containing 0.4 mol / L NaIO4 and 0.32 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 8 wt% glutaraldehyde and pH 7.8, and 18 g of myricetin was added. The reaction was carried out at 55 ℃ for 3.0 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 15 wt%, and the temperature was raised to 65 ℃ to continue the reaction for 6 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0048] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 89.4°, pore size distribution peak 0.53 μm; tannin loading: 529 mg / g; pure water flux: 283 L / (m²·h); seawater uranium extraction: adsorption capacity 8.4±0.2 mg / g; antifouling: flux retention rate 83%.

[0049] Example 10 Preparation of high-throughput cellulose-cured tannin membrane adsorbent material Aldehyde modification: A cellulose acetate microporous filter membrane was immersed in an aqueous solution containing 0.10 mol / L NaIO4 and 0.15 mol / L NaCl and reacted at 50 °C in the dark for 6 h; then the oxidation was terminated with 0.1 mol / L ethylene glycol and washed three times with deionized water to obtain an aldehyde-modified membrane; Gradient crosslinking curing: Pre-crosslinking: The aldehyde-modified membrane was placed in 100 mL of phosphate buffer containing 6 wt% glutaraldehyde and pH 7.8, and 16 g of myricetin was added. The reaction was carried out at 50 ℃ for 2.5 h. Curing crosslinking: Glutaraldehyde was added to bring the total to 12 wt%, and the temperature was raised to 65 ℃ to continue the reaction for 5 h, while maintaining pH 7.8 throughout the process. After the reaction was complete, the membrane was thoroughly rinsed with deionized water and dried under vacuum at 60 °C to obtain the BT-CA membrane.

[0050] The properties of the BT-CA membrane prepared in this embodiment are as follows: Membrane structure: static water contact angle 78.8°, pore size distribution peak 0.68 μm; tannin loading: 464 mg / g; pure water flux: 315 L / (m²·h); seawater uranium extraction: adsorption capacity 7.3±0.2 mg / g; antifouling: flux retention rate 91%.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-flux cellulose-cured tannin membrane adsorbent material, characterized in that, It includes an aldehyde-modified cellulose acetate microporous filter membrane and myricetin that is cured onto the microporous filter membrane by gradient crosslinking.

2. The high-throughput cellulose-cured tannin membrane adsorbent material as described in claim 1, characterized in that, The loading of tannins in bayberry is ≥400 mg / g.

3. The high-throughput cellulose-cured tannin membrane adsorbent material as described in claim 1 or 2, characterized in that, The adsorbent material has a dynamic pure water flux ≥300 L / (m²·h) and a dynamic adsorption capacity ≥0.45 mmol / g for a 0.05 mmol / L UO2²⁺ solution.

4. The high-throughput cellulose-cured tannin membrane adsorbent material as described in claim 1, characterized in that, Aldehyde-modified cellulose acetate microporous membranes are obtained by selectively oxidizing the hydroxyl groups of cellulose acetate microporous membranes with sodium periodate to form aldehyde groups.

5. The method for preparing the high-throughput cellulose-cured tannin membrane adsorbent material as described in any one of claims 1-4, characterized in that, include: Cellulose acetate microporous membranes were immersed in a solution containing sodium periodate and sodium chloride, and the reaction was terminated after being exposed to light at 50°C for 4–8 hours. The membranes were then washed to obtain aldehyde-modified cellulose acetate microporous membranes. Aldehyde-modified cellulose acetate microporous membranes were pre-crosslinked with myricetin in low concentration glutaraldehyde at 50–55℃ and pH 7.5–8.0 for 2–3 h. Supplement with glutaraldehyde and cure and crosslink at high concentrations of glutaraldehyde, 65–70℃, and pH 7.5–8.0 for 5–6 hours; The adsorbent material is obtained after washing and drying.

6. The preparation method according to claim 5, characterized in that, During the pre-crosslinking stage, the glutaraldehyde concentration is 5–8 wt%.

7. The preparation method according to claim 5, characterized in that, During the curing and crosslinking stage, the glutaraldehyde concentration is 10–15 wt%.

8. The preparation method according to claim 5, characterized in that, The reaction was terminated with ethylene glycol after reacting at 50°C in the dark for 4–8 hours.

9. The use of the high-throughput cellulose-cured tannin membrane adsorbent material as described in any one of claims 1-4 for the continuous extraction of uranium from seawater or uranium-containing wastewater.

10. The use as described in claim 9, characterized in that, The adsorbent material, as a dynamic filtration adsorption membrane, is configured in the membrane module of a multi-stage tandem uranium extraction system. Under the conditions of feed uranium concentration of 0.03–0.3 μg / L and flow rate of 10–50 mL / min, the single-stage membrane achieves a single-stage rejection rate of ≥95% for UO2²⁺, and after elution with 0.1 mol / L HNO3, the adsorption capacity recovery rate is ≥98%, and it can be recycled ≥20 times.

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