A sodium alginate loaded short cotton wrapped co-mn-ldhs aerogel material, a preparation method and application thereof

Abstract

The application belongs to the technical field of water treatment and catalytic material, and particularly relates to a sodium alginate loaded short cotton wrapped CoMn-LDHs aerogel material and a preparation method and application thereof. The preparation method of the aerogel material provided by the application wraps CoMn-LDH nanoparticles by sodium alginate, and a porous aerogel material is prepared with the aid of short cotton. The addition of the short cotton changes the water flux of the aerogel and at the same time strengthens the mechanical properties. Experiments prove that the aerogel material can effectively activate peroxymonosulfate to degrade ciprofloxacin within the pH range of 3-11, the degradation rate of ciprofloxacin reaches 82.3%, and the aerogel material has good cycle stability, can solve the problems of difficult separation of powder catalyst and difficult balance between mechanical properties and water flux of the aerogel, has a wide application prospect in the field of antibiotic wastewater treatment, and has important guiding value for the development of catalytic materials for water treatment.

Description

Technical Field

[0001] This invention belongs to the field of water treatment and catalytic materials technology, specifically relating to an aerogel material of sodium alginate-supported short cotton fibers encapsulating CoMn-LDHs, its preparation method, and its application. Background Technology

[0002] Ciprofloxacin (CIP) is a synthetic third-generation fluoroquinolone antibiotic widely used in the treatment of humans and animals. However, in recent years, ciprofloxacin has been frequently detected in various aquatic environments. It can be transferred along the food chain, promoting the development and enhancement of bacterial resistance, and its persistent presence poses a potential threat to the integrity of ecosystems and human health. Furthermore, the overuse of ciprofloxacin not only promotes the emergence of drug-resistant strains but also causes multifaceted harm through environmental residues, food chain enrichment, and horizontal gene transfer pathways, leading to a year-on-year increase in the number of people infected with antibiotic-resistant bacteria globally. Therefore, there is an urgent need to develop economically feasible methods for effectively removing ciprofloxacin and other antibiotics from the aquatic environment.

[0003] Currently, various water treatment technologies have been developed for antibiotic removal in aquatic environments, including physical adsorption, electrochemical methods, biological methods, and advanced oxidation methods. Among these, adsorption is simple to operate and inexpensive, but it suffers from drawbacks such as difficulty in adsorbent regeneration, the generation of secondary pollutants, and the inability to mineralize pollutants. Electrochemical methods are hampered by high electrode costs and high energy consumption. Biological methods are ill-suited to extreme environments such as low temperatures and high salinity. Among existing treatment technologies, advanced oxidation processes (AOPs) based on peroxodisulfate (PMS) have been extensively studied for degrading organic pollutants. Compared to hydroxyl-based AOPs (·OH, E0 = 1.8V~2.7V), potassium persulfate-based AOPs (SO4··OH ... − PMS (with an oxidation state of E0 = 2.5V~3.1V) has attracted increasing attention due to its advantages such as higher oxidation capacity, wider pH range, longer catalytic utilization time, and superior selective oxidation ability. Among these advantages, the activation of PMS is crucial to the oxidation process, and the catalyst plays a decisive role in it.

[0004] Layered double hydroxides (LDHs), also known as hydrotalcite compounds, are layered materials assembled through anionic intercalation using metal hydroxides as laminations. They possess abundant surface hydroxyl groups and tunable types and proportions of metal elements in the laminations. Among them, transition metal-based LDHs are widely used to activate PMS for the degradation of organic pollutants due to their excellent electron transport capabilities, low cost, and good stability. Meanwhile, CoMn-LDHs have become promising catalyst materials due to their highly controllable structure and chemical properties. However, most existing CoMn-LDH catalysts are in solid powder form, making them difficult to separate and recover from the reaction system after use, thus limiting their practical applications.

[0005] Sodium alginate is a natural anionic polysaccharide with excellent hydrophilicity, biocompatibility, and biodegradability, as well as outstanding ion exchange and gel-forming capabilities, showing potential for application in wastewater treatment and other fields. Existing research has used sodium alginate combined with graphene oxide to prepare aerogels for heavy metal adsorption, or encapsulated kaolin in sodium alginate to prepare composite microspheres for dye adsorption. However, research on using sodium alginate aerogel as a catalyst carrier for LDHs while simultaneously addressing the catalyst separation and recovery issues is still insufficient. Furthermore, existing sodium alginate-based aerogels often struggle to balance mechanical properties and water flux; excessive water flux results in insufficient catalytic reaction residence time, while insufficient water flux leads to low treatment efficiency. In addition, to address the degradation of pharmaceutical wastewater under conditions without sunlight and achieve stable operation around the clock, developing sunlight-independent water treatment technologies has significant application value.

[0006] Therefore, developing a supported LDHs aerogel material that can maintain the high catalytic activity of CoMn-LDHs, enable convenient separation and recovery, and has good water permeability and catalytic efficiency, in order to achieve the effective removal of antibiotics such as ciprofloxacin in aquatic environments under light-free conditions, has important practical application value. Summary of the Invention

[0007] This invention addresses the technical shortcomings of existing LDH powder catalysts, such as difficulties in separation and recovery, and the challenge of balancing mechanical properties and water flux in sodium alginate-based aerogels. It provides an aerogel material composed of sodium alginate-supported short cotton fibers encapsulating CoMn-LDHs, along with its preparation method and applications. This aerogel material maintains high water flux while possessing good mechanical properties and excellent catalytic activity, enabling efficient activation of persulfate-degraded antibiotic wastewater over a wide pH range under light-free conditions.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing an aerogel material containing sodium alginate-loaded short cotton fibers encapsulating CoMn-LDHs includes the following steps: (1) Dissolve sodium alginate in water to obtain sodium alginate solution; add CoMn-LDHs nanoparticles and short cotton fibers to the sodium alginate solution and stir evenly to obtain a mixed dispersion; (2) The mixed dispersion is freeze-formed and then freeze-dried to obtain a nascent gel; (3) The initial aerogel is immersed in a calcium ion solution for cross-linking treatment, and then the cross-linked aerogel is freeze-dried to obtain the sodium alginate-loaded short cotton wool-encapsulated CoMn-LDHs aerogel material.

[0009] Preferably, in step (1), the concentration of the sodium alginate solution is 3%~5%m / V, more preferably 4%m / V. The dissolution temperature is 70~90℃; the fiber length of the short cotton linter is 5~10mm.

[0010] Preferably, in step (1), the preparation method of the CoMn-LDHs nanoparticles includes the following steps: using cobalt salt and manganese salt as metal sources, and triethanolamine and urea as dual alkali sources; mixing cobalt salt, manganese salt, triethanolamine and urea evenly in water, and then hydrothermally reacting at a temperature of 100~140℃ for 1~4h; washing, drying, grinding and sieving the obtained reaction product to obtain the CoMn-LDHs nanoparticles.

[0011] More preferably, the cobalt salt is cobalt nitrate hexahydrate; the manganese salt is manganese nitrate tetrahydrate; the molar ratio of the cobalt salt to the manganese salt is 1:(0.8~1.2), more preferably 1:1. The molar ratio of triethanolamine to urea is 1:(1.8~2.2), more preferably 1:2. Through experiments, this invention has found that using a dual-alkali source of triethanolamine and urea for the preparation of CoMn-LDHs nanoparticles can further improve the specific surface area and porosity of the material compared to using a single alkali source of urea, thereby enhancing catalytic activity. Based on the use of a dual-alkali source, this invention controls the molar ratio of triethanolamine to urea to be 1:2, 1:1, and 2:1, and further determined through experiments that the optimal molar ratio of triethanolamine to urea is 1:2.

[0012] More preferably, the hydrothermal reaction is carried out at a temperature of 120°C for 2 hours.

[0013] Preferably, in steps (2) and (3), the freeze-drying process is carried out at a temperature of -30 to -20°C for 20 to 30 hours.

[0014] Preferably, in step (3), the calcium ion solution is a calcium chloride solution; the concentration of the calcium chloride solution is 2wt%~5wt%; and the crosslinking treatment time is 4~8h.

[0015] An aerogel material containing CoMn-LDHs loaded with short cotton fibers and prepared by the above method includes CoMn-LDHs nanoparticles and a sodium alginate aerogel matrix; the CoMn-LDHs nanoparticles are loaded in the sodium alginate aerogel matrix; short cotton fibers are also dispersed in the sodium alginate aerogel matrix as a skeletal support material.

[0016] Preferably, the CoMn-LDHs nanoparticles have a sea urchin-like morphology and are formed by the accumulation of needle-like particles; the aerogel material has a layered porous structure containing interconnected pores and channels arranged vertically along the growth direction.

[0017] The application of an aerogel material containing CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers as described above, as a catalyst in the activation of persulfate degradation of antibiotic-containing wastewater.

[0018] Preferably, the application specifically involves using the aerogel material as a catalytic filter material, allowing wastewater containing antibiotics and persulfate to flow through the aerogel material, thereby achieving antibiotic degradation.

[0019] Preferably, the antibiotic is selected from one or more of ciprofloxacin, norfloxacin, and ofloxacin; the pH range of the degradation is 3 to 11; the degradation is carried out under conditions without external light; and the concentration of the added persulfate is 0.5 to 1.25 mM.

[0020] The overall beneficial effects of this invention are as follows: (I) This invention uses triethanolamine and urea as dual alkali sources to synthesize sea urchin-like CoMn-LDH nanoparticles via a hydrothermal method. Triethanolamine, with its relatively low toxicity and biodegradability, acts as a multifunctional and highly efficient stabilizer, slowly releasing alkalinity to achieve precise control over the synthesis process and optimize the material morphology and particle size. The resulting CoMn-LDHs possess abundant mesoporous structures, which is beneficial for exposing active sites and enhancing catalytic activity.

[0021] (II) This invention loads CoMn-LDHs nanoparticles into sodium alginate aerogel, effectively solving the problem of difficult separation and recovery of powdered catalysts. In particular, the introduction of short cotton fibers (DC) provides skeletal support for the internal structure of the aerogel, significantly improving the compressive strength and elastic recovery ability of the aerogel. Under 50% compressive strain, the aerogel material (CoMn-LDHs / SA / DC) of this invention can recover to its original height within 5 seconds after pressure release.

[0022] (III) This invention, through the introduction of short cotton fibers, ensures a high porosity (62.74%) and water flux (4041.22 L / (m³) of the aerogel. 2Simultaneously, the catalytic reaction is fully carried out. Compared with the aerogel material CoMn-LDHs / SA without added short cotton fibers, the aerogel of the present invention achieves a single-pass removal rate of 72.15% under suitable water flux; and compared with materials with added carboxymethyl cellulose, the present invention has a higher treatment efficiency.

[0023] (iv) The aerogel material of the present invention has excellent hydrophilic properties, and water droplets can be completely penetrated in just 0.64s. The super hydrophilicity is beneficial to liquid transport in actual use.

[0024] (v) The aerogel material of the present invention can effectively activate PMS to degrade the antibiotic ciprofloxacin in a wide pH range of 3 to 11. Under natural pH conditions, the degradation rate of CIP reaches 82.3% within 20 minutes. It also has good degradation effects on various fluoroquinolone antibiotics such as norfloxacin and ofloxacin, and has strong applicability.

[0025] (vi) The aerogel material of the present invention has good reusability. After four cycles, the CIP degradation rate can still reach 70.92%, demonstrating excellent cycle stability. At the same time, the catalytic system also has a high efficiency in degrading antibiotics in actual water bodies such as tap water and river water, showing good prospects for practical application.

[0026] Therefore, the aerogel material provided by this invention solves the problems of difficult separation of powder catalysts and difficulty in balancing the mechanical properties and water flux of aerogels. It has broad application prospects in the field of antibiotic wastewater treatment and has important guiding value for the development of catalytic materials for water treatment. Attached Figure Description

[0027] Figure 1 The images show the XRD pattern, FT-IR pattern, DTG pattern, and BET pattern of CoMn-LDHs and CoMn-LDHs / SA / DC materials in Embodiment 1 of the present invention; wherein, (a) is the XRD pattern, (b) is the FT-IR pattern, (c) is the DTG pattern, and (d) is the BET pattern. Figure 2 The images shown are SEM images, appearance images, and EDS images of CoMn-LDHs and CoMn-LDHs / SA / DC materials according to Embodiment 1 of the present invention; wherein, (a)~(b) are SEM images of CoMn-LDHs, (c)~(e) are SEM images of CoMn-LDHs / SA / DC, (f)~(g) are appearance images of CoMn-LDHs / SA / DC, (h) is an EDS image of CoMn-LDHs, and (i) is an EDS image of CoMn-LDHs / SA / DC. Figure 3The mechanical property test results of the aerogel materials of Example 1 and Comparative Examples 1 to 3 in this invention are shown; wherein, (a) is CoMn-LDHs / SA; (b) is CoMn-LDHs / SA / CMC; (c) is CoMn-LDHs / SA / DC; and (d) is CoMn-LDHs / SA / CMC / DC. Figure 4 The results are the water absorption performance test results of the aerogel materials of Example 1 and Comparative Examples 1 to 3 in this invention; wherein, (a) is CoMn-LDHs / SA; (b) is CoMn-LDHs / SA / CMC; (c) is CoMn-LDHs / SA / DC; and (d) is CoMn-LDHs / SA / CMC / DC. Figure 5 The following are the test results of catalytic performance, porosity, density, water flux and stress-strain of the aerogel materials of Example 1 and Comparative Examples 1 to 3 in this invention; wherein, (a) is catalytic performance; (b) is porosity and density; (c) is water flux and catalytic performance in one cycle; and (d) is the stress-strain curve of the aerogel of Example 1. Figure 6 The results show the catalytic performance of the CoMn-LDHs material in Example 1 of this invention under different conditions: with / without PMS, different pH, and different catalyst concentrations. Among them, (a) shows the effect of adding / without adding PMS on CIP degradation, (b) shows the catalytic performance evaluation of CoMn-LDHs, and (c) and (d) show the effect of different pH and different catalyst concentrations on CIP degradation, respectively. Figure 7 The results show the catalytic performance, cycle performance, and water quality test results of the CoMn-LDHs material in Example 1 of this invention at different reaction temperatures; where (a) represents the degradation performance at different temperatures (15-30℃), (b) to (c) represent the evaluation of the catalyst's cycle performance, and (d) represents the degradation performance under different water qualities. Figure 8 This invention illustrates the effects of different anions and organic compounds on the degradation of activated PMS by CoMn-LDHs material in Example 1; where (a) shows the effect of different anions on the degradation effect, and (b) shows the effect of organic compound HA on the degradation effect. Figure 9 The images show the spectral scanning results of different antibiotic systems and the removal rates of different antibiotics in this invention; where (a) to (c) are the spectral scanning results of ciprofloxacin, norfloxacin, and ofloxacin, respectively, and (d) is the removal rate result of different antibiotics. Figure 10The results show the catalytic performance evaluation of the CoMn-LDHs / SA / DC aerogel material in Example 1 of this invention; where (a) is the catalytic performance of the material with / without PMS; (b) is the catalytic performance at different reaction temperatures; (c) is the catalytic performance at different pH values; and (d) is the catalytic performance at different CoMn-LDHs / SA / DC concentrations. Figure 11 This invention presents the single-pass water permeation catalytic performance, cycle stability, and degradation effect of CoMn-LDHs / SA / DC under optimal conditions in Example 1 of this invention; wherein, (a) represents the single-pass water permeation catalytic performance, (b) to (c) represent the cycle performance evaluation, and (d) represents the degradation performance in different water qualities. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to specific embodiments, but this does not constitute a limitation on the present invention.

[0029] In the following embodiments, sodium alginate, carboxymethyl cellulose, and potassium persulfate (PMS) were sourced from Shanghai Maclean's brand. Short cotton linters (DC) were purchased from Heze Yangxue Sanitary Materials Co., Ltd., with a fiber length of 5-10 mm. All other raw materials not specified were analytical grade materials obtained through commercial channels, and all water used was deionized water.

[0030] In the following embodiments of the present invention, ciprofloxacin was quantitatively tested using a UV-Vis spectrophotometer and a pre-established standard curve. The standard curve was established as follows: 200 mg of ciprofloxacin powder was accurately weighed, dissolved, and poured into a 1 L volumetric flask for dilution. The solution was then transferred to a brown bottle and stored in a cool, dark place. Subsequent experiments used this solution for dilution. The maximum absorption wavelength of ciprofloxacin was determined to be 277 nm using a full-wavelength scan with a UV-Vis spectrophotometer. Based on this, high-performance liquid chromatography (HPLC) was performed on ciprofloxacin standard solutions with concentrations ranging from 5.0 to 25.0 mg / L at the characteristic wavelength, and a linear regression standard curve was constructed accordingly. The fitting results showed that the standard curve for ciprofloxacin was Y = 0.0464X + 0.0078, and the coefficient of determination R0 was [value missing]. 2 The result was 0.9998. This indicates that within the selected concentration range, there is an excellent linear correlation between the mass concentration of the target analyte and the response intensity, which can be used for the quantification of ciprofloxacin. Furthermore, the quantification procedures for norfloxacin and ofloxacin were performed using the same method as for ciprofloxacin. Example

[0031] This embodiment provides an aerogel catalyst for CoMn-LDHs encapsulated in short cotton fibers and supported by sodium alginate. The preparation method includes the following steps: S1. Preparation of CoMn-LDHs by hydrothermal synthesis method Weigh out 0.005 mol each of manganese nitrate tetrahydrate and cobalt nitrate hexahydrate (total molar amount 0.01 mol, cobalt-manganese molar ratio 1:1), place them in a beaker, add 12 mL of deionized water and stir for 5 min to dissolve, obtaining a mixed solution. Add triethanolamine and urea dropwise to the mixed solution. After addition, the total molar concentration of triethanolamine and urea in the solution is 30 mM, and the molar ratio of triethanolamine to urea is 1:2. After addition, stir at 500 rpm for 5 min to obtain the precursor solution.

[0032] The precursor solution was transferred to a reaction vessel lined with polytetrafluoroethylene (PTFE), sealed, and placed in a 120°C drying oven for hydrothermal reaction for 2 hours. After the reaction was complete, the product was washed three times each with deionized water and anhydrous ethanol, dried at 60°C, ground, and sieved (200 mesh) to obtain the nanoparticle powder, which is CoMn-LDHs.

[0033] S2, Preparation of aerogel catalysts 4g of sodium alginate (SA) powder was dissolved in 100mL of deionized water at 80℃, and stirred continuously at 1000rpm for 1h to obtain a sodium alginate solution with a concentration of 4%m / V. 0.6g of CoMn-LDHs prepared in step S1 and 1g of short cotton fibers (DC) were added to the sodium alginate solution under rapid stirring at 1000rpm, and stirring was continued for 1h to obtain a homogeneous mixed dispersion.

[0034] The mixed dispersion was poured into a 10 cm diameter petri dish and frozen at -25 °C to form a gel. Then, it was freeze-dried at -25 °C for 24 h to obtain the freeze-dried aerogel. The aerogel was then immersed in a 3 wt% CaCl2 solution for 6 h for crosslinking. It was then rinsed with deionized water to remove uncrosslinked CaCl2 and finally freeze-dried again at -25 °C for 24 h to obtain the sodium alginate-supported short cotton wool-encapsulated CoMn-LDHs aerogel catalyst of this embodiment, denoted as CoMn-LDHs / SA / DC.

[0035] Comparative Example 1 This comparative example provides an aerogel catalyst, the preparation method of which is similar to that of Example 1, except that the use of short cotton fibers is omitted in step S2. That is, the corresponding step of step S2 is adjusted as follows: 0.6g of CoMn-LDHs obtained in step S1 is added to the sodium alginate solution, and stirring is continued for 1h to obtain a uniform mixed dispersion. The remaining steps are the same as in Example 1. The aerogel catalyst obtained is denoted as CoMn-LDHs / SA.

[0036] Comparative Example 2 This comparative example provides an aerogel catalyst, the preparation method of which is similar to that of Example 1, except that sodium carboxymethyl cellulose is used instead of short cotton fibers in step S2. That is, the corresponding step of step S2 is adjusted as follows: 0.6g of CoMn-LDHs obtained in step S1 is added to the above sodium alginate solution, and 2g of sodium carboxymethyl cellulose (CMC) is added at the same time. The mixture is stirred for 1 hour to obtain a uniform mixed dispersion. The remaining steps are the same as in Example 1. The aerogel catalyst obtained is denoted as CoMn-LDHs / SA / CMC.

[0037] Comparative Example 3 This comparative example provides an aerogel catalyst, the preparation method of which is similar to that of Example 1, except that 2g of sodium carboxymethyl cellulose (CMC) is added in step S2. That is, the corresponding step of step S2 is adjusted as follows: 0.6g of CoMn-LDHs obtained in step S1 is added to the above sodium alginate solution, along with 1g of short cotton fibers (DC) and 2g of sodium carboxymethyl cellulose (CMC), and the mixture is stirred for 1 hour to obtain a uniform mixed dispersion. The remaining steps are the same as in Example 1. The aerogel catalyst obtained is denoted as CoMn-LDHs / SA / CMC / DC.

[0038] Comparative Example 4 This comparative example provides an aerogel catalyst, the preparation method of which is similar to that of Example 1, except that CoMn-LDHs are not added in step S2. That is, step S1 is omitted, and the corresponding step in step S2 is adjusted as follows: 1g of short cotton fibers (DC) are added to the above sodium alginate solution, and stirring is continued for 1h to obtain a uniform mixed dispersion. The remaining steps are the same as in Example 1. The resulting aerogel catalyst is denoted as SA / DC.

[0039] Experimental Example 1: Structural Characterization of CoMn-LDHs and CoMn-LDHs / SA / DC The CoMn-LDHs prepared in step S1 of Example 1 and the CoMn-LDHs / SA / DC prepared in step S2 were characterized structurally, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential thermogravimetric analysis (DTG), N2 adsorption-desorption analysis (BET), scanning electron microscopy (SEM), and elemental composition spectroscopic analysis (EDS). The appearance of CoMn-LDHs / SA / DC was also recorded. The FT-IR analysis scan range was 4000-650 cm⁻¹. −1 DTG analysis was performed in a nitrogen atmosphere at 800°C with a heating rate of 10°C / min.

[0040] Figure 1The images show the XRD, FT-IR, DTG, and BET plots of the CoMn-LDHs and CoMn-LDHs / SA / DC materials of Example 1; where (a) is the XRD plot, (b) is the FT-IR plot, (c) is the DTG plot, and (d) is the BET plot.

[0041] Depend on Figure 1 As shown in (a), the CoMn-LDHs nanomaterials exhibit typical hydrotalcite structure characteristic peaks (JCPDS NO. 50-0235). The 2θ values ​​of CoMn-LDHs at 12.18°, 23.9°, 34.26°, 38.55°, 46.06°, 59.24°, and 60.43° correspond to the diffraction peaks of the (003), (006), (012), (015), (018), (110), and (113) crystal planes, respectively, and exhibit typical LDHs characteristic peaks.

[0042] Depend on Figure 1 From (b) we can see that 800cm ﹣1 The absorption peaks in the vicinity may be due to the stretching vibrations of MO (where M is Co or Mn), indicating lattice vibrations caused by the successful entry of metal cations. NO3 on LDHs materials ﹣ The asymmetric stretching vibration corresponds to 1383 cm. ﹣1 The strong absorption peak at [value missing] indicates the presence of anions in the LDHs material. The bending vibration of -OH in the material corresponds to [value missing] cm⁻¹. ﹣1 The absorption peak at 1418 cm⁻¹ is related to the bending vibrations of interlayer water molecules and -OH groups, proving the presence of interlayer water of crystallization in this material. Conversely, the absorption peak at 1418 cm⁻¹... ﹣1 and 1392cm ﹣1 The characteristic band observed is attributed to the antisymmetric stretching vibration of O=C=O within the material. Meanwhile, the stretching vibration of -OH in the LDHs material is at 3442 cm⁻¹. ﹣1 The absorption peaks in the vicinity correspond to these peaks. These results indicate that CoMn-LDHs exhibit typical metal vibrational peaks, and that nitrate groups have successfully intercalated into the adsorbent interlayer.

[0043] like Figure 1 As shown in (c), CoMn-LDHs exhibit four endothermic peaks with slightly different temperatures. The weight loss at 80–130 °C is due to the loss of interlayer water molecules, and the material structure is not damaged. The two endothermic peaks at 200–350 °C are attributed to the dehydroxylation of CoMn-LDHs and the release of interlayer NO3. ﹣ The decomposition of LDHs; the exothermic peak at 390~410℃ is attributed to the decomposition of LDHs and the conversion of LDHs to LDOs.

[0044] Figure 1Figure (d) shows the N2 adsorption-desorption curves and corresponding pore size distributions of CoMn-LDHs and CoMn-LDHs / SA / DC. Within the relative pressure (P / P0) range of 0–0.8, the increase in N2 adsorption capacity of CoMn-LDHs is relatively gradual, and the adsorption and desorption processes almost overlap, indicating that the adsorption capacity of the material is relatively stable within this pressure range. However, for CoMn-LDHs, the N2 adsorption capacity shows a slow increasing trend within the relative pressure (P / P0) range of 0–0.4, but when the relative pressure reaches 0.6–1, the N2 adsorption capacity increases rapidly, and a type IV isotherm adsorption curve dominated by mesopores appears. This is because capillary condensation caused by the porous structure inside the material makes it easier for N2 molecules to be adsorbed into the pores of the material in the high-pressure range. Based on the nitrogen adsorption-desorption isotherm, the specific surface area of ​​CoMn-LDHs is 70.5944 m². 2 The surface area is 0.2320 m² / g, with an average pore size of 20.0182 nm. The large specific surface area and mesoporous structure are beneficial for the exposure of active sites and the improvement of catalytic activity. In the relative pressure (P / P0) range of 0 to 0.45, the N₂ adsorption capacity of the CoMn-LDHs / SA porous aerogel increases relatively slowly, and the adsorption and desorption processes almost overlap, indicating that the adsorption capacity of the material is relatively stable within this pressure range. However, for the CoMn-LDHs / SA aerogel, the N₂ adsorption capacity shows a slow increasing trend in the relative pressure (P / P0) range of 0 to 0.4, but when the relative pressure reaches 0.45 to 1, the N₂ adsorption capacity increases rapidly, and a typical H₃-type hysteresis loop appears. According to the nitrogen adsorption-desorption isotherm, the specific surface area of ​​the CoMn-LDHs / SA / DC porous aerogel is 0.2320 m² / g. 2 / g, with an average pore size of 25.67nm. Furthermore, this invention further compares CoMn-LDHs / SA / DC with CoMn-LDHs / SA, CoMn-LDHs / SA / CMC, and CoMn-LDHs / SA / CMC / DC, finding that CoMn-LDHs / SA / DC has more mesoporous and macroporous structures, resulting in a larger specific surface area. This larger specific surface area and pore structure are beneficial for exposing active sites and improving catalytic activity.

[0045] Figure 2The images shown are SEM images, appearance images, and EDS images of CoMn-LDHs and CoMn-LDHs / SA / DC from Example 1; where (a) to (b) are SEM images of CoMn-LDHs, (c) to (e) are SEM images of CoMn-LDHs / SA / DC, (f) to (g) are appearance images of CoMn-LDHs / SA / DC, (h) is an EDS image of CoMn-LDHs, and (i) is an EDS image of CoMn-LDHs / SA / DC.

[0046] from Figure 2 As can be seen from (a) and (b), the CoMn-LDHs particles have a high degree of dispersion and are approximately needle-like, forming a sea urchin-like structure.

[0047] CoMn-LDHs were further uniformly dispersed in SA and DC-based aerogels, and the internal morphology of the prepared CoMn-LDHs / SA / DC aerogels was observed using scanning electron microscopy, such as... Figure 2 As shown in (c) to (e), the aerogel surface is relatively rough, with particles of varying sizes distributed on the surface. The presence of these particles is attributed to the successful attachment of CoMn-LDHs. Furthermore, the CoMn-LDHs / SA / DC aerogel possesses a layered porous structure containing interconnected pores and channels arranged perpendicularly along the growth direction. This unique structure exhibits low mass transfer resistance and strong capillary effect, which is highly conducive to the adsorption of pollutants.

[0048] Further from Figure 2 As can be seen from the appearance diagrams of (f) to (g) aerogels, the present invention can prepare aerogel materials with regular dimensions.

[0049] Figure 2 (h) and (i) in the figure are EDS diagrams of CoMn-LDHs and CoMn-LDHs / SA / DC, respectively. The uniform distribution of Co and Mn elements in the particles in the figure confirms the successful preparation of sea urchin-shaped CoMn-LDHs. At the same time, the uniform distribution of Co and Mn elements in the aerogel confirms the successful preparation of CoMn-LDHs / SA / DC aerogel.

[0050] Experimental Example 2: Mechanical and Water Absorption Properties Testing of Different Aerogel Materials Aerogels are particularly valued for their excellent mechanical properties and significant deformation recovery in applications. Furthermore, in interfacial water permeability applications driven by gravity, ensuring a continuous supply of interfacial water is crucial, which requires the interfacial material to possess good hydrophilicity. Therefore, this invention conducted mechanical and water absorption property tests on the aerogel materials prepared in Example 1 and Comparative Examples 1-3, respectively, and the results are as follows: Figure 3 and Figure 4 As shown.

[0051] In the mechanical property testing, this invention used a direct weighting method to test the compressive strength and elastic recovery of aerogels prepared by different methods at a compressive strain of 50%. Water absorption was assessed using a contact angle test to evaluate the hydrophilicity of different aerogels. During the test, a flat area of ​​the sample surface was selected, and the sample was cut into strips approximately 1×10 cm in length. These strips were then attached to the edge of a glass slide. The water contact angle of the sample was observed using a dynamic contact angle meter at a constant temperature. Water droplet size was selected as 2 μL, and measurements were taken at 1 cm intervals. Each sample film was measured three times to minimize cross-contamination errors. The initial average contact angle was recorded.

[0052] Figure 3 The mechanical property test results of the aerogel materials prepared in Example 1 and Comparative Examples 1 to 3 are shown below; where (a) is the result of CoMn-LDHs / SA; (b) is the result of CoMn-LDHs / SA / CMC; (c) is the result of CoMn-LDHs / SA / DC; and (d) is the result of CoMn-LDHs / SA / CMC / DC.

[0053] like Figure 3 As shown in (a) to (d), when the compressive strain of the aerogel is 50%, CoMn-LDHs / SA / DC recovers to its original height within 5 seconds after pressure release. However, CoMn-LDHs / SA, CoMn-LDHs / SA / CMC, and CoMn-LDHs / SA / CMC / DC cannot recover to their original structures. This indicates that the addition of short fibers provides skeletal support for the internal structure of the aerogel, and the cross-linked short fiber aerogel has good compressive strength and elastic recovery ability. Simultaneously, this aerogel also exhibits good resilience in water; CoMn-LDHs / SA / DC can rebound to its initial state after underwater compression.

[0054] Figure 4 The results are the water absorption performance test results of the aerogel materials prepared in Example 1 and Comparative Examples 1 to 3; where (a) is the result of CoMn-LDHs / SA; (b) is the result of CoMn-LDHs / SA / CMC; (c) is the result of CoMn-LDHs / SA / DC; and (d) is the result of CoMn-LDHs / SA / CMC / DC.

[0055] like Figure 4As shown in (a) to (d), in the contact angle test, water droplets spread rapidly on the sample surface after being dropped, indicating that sodium alginate-supported CoMn-LDHs aerogels all exhibit excellent hydrophilicity. Specifically, for the CoMn-LDHs / SA aerogel, the water contact angle required for complete penetration of the aerogel by a water droplet is 0.35 s. For the CoMn-LDHs / SA / CMC aerogel, the water contact angle required 2.8 s. For the CoMn-LDHs / SA / DC aerogel, the water contact angle required only 0.64 s. For the CoMn-LDHs / SA / DC / CMC aerogel, the water contact angle required 1.4 s. This invention demonstrates that the addition of short cotton fibers improves the hydrophilicity of the aerogel, while the addition of carboxymethyl cellulose reduces its hydrophilicity. This is because sodium alginate itself is a natural linear polysaccharide extracted from brown algae, and its structural units are rich in hydroxyl and sodium carboxylate hydrophilic groups. The hydroxyl groups can form strong hydrogen bonds with water molecules. Under alkaline conditions, the carboxylate groups in sodium alginate exist in the form of sodium salts, exhibiting strong hydrophilicity and ionization ability. Furthermore, the short cotton fibers provide support, resulting in significant capillary action between the sodium alginate channels, rapidly drawing water droplets to their surroundings. This superior hydrophilicity is beneficial for liquid transport during the practical application of the permeable interfacial material. However, the introduction of carboxymethyl cellulose makes the channels denser, reducing the liquid transport effect and hindering efficient catalytic reactions.

[0056] Experimental Example 3: Catalytic performance, porosity, density, water flux, and stress-strain testing of different aerogel materials. Furthermore, the present invention conducted catalytic performance, porosity, density, water flux, and stress-strain tests on the aerogel materials prepared in Example 1 and Comparative Examples 1-3, respectively. Specifically, the aerogel of Example 1 is designated as the SA+DC group, the aerogel of Comparative Example 1 as the SA group, the aerogel of Comparative Example 2 as the SA+CMC group, and the aerogel of Comparative Example 3 as the SA+CMC+DC group.

[0057] In the catalytic performance test, this invention used deionized water to construct a reaction system containing ciprofloxacin (CIP). The initial concentration of ciprofloxacin in each system was 10 mg / L, and the volume was 100 mL. The initial pH value of the solution (6.69) was maintained constant. Persulfate (PMS, specifically potassium persulfate) was added to the system as an oxidant at a concentration of 0.75 mM. The degradation experiment was carried out at 25°C. The degradation process did not require additional light and was performed directly under natural light. The degradation was carried out by pouring the prepared ciprofloxacin-containing wastewater into a burette containing an aerogel filter cartridge of the same specification (27 mm in diameter and 3 cm in thickness). The residual concentration and removal rate of ciprofloxacin were measured.

[0058] Porosity was tested using the dry / wet film gravimetric method. During testing, the sample was taken from deionized water and cut to a suitable size. The deionized water adhering to the sample surface was removed, and its thickness and mass were measured using a digital micrometer thickness gauge and an electronic balance, respectively. The sample was then dried in a 60°C electrically heated drying oven, with the mass measured every hour. The mass at which the sample no longer changed was taken as the dry weight. Each sample was tested at least three times, and the porosity was calculated based on the test data.

[0059] The stress-strain test was conducted using a universal testing machine to test the compressive strength of the aerogel. The aerogel was subjected to compressive strains of 20%, 40%, 60%, and 80% in the transverse direction at a compression rate of 400 mm / min.

[0060] Figure 5 Table 1 shows the catalytic performance, porosity, density, water flux, and stress-strain test results of the aerogel materials prepared in Example 1 and Comparative Examples 1-3. (a) represents catalytic performance; (b) represents porosity and density; (c) represents water flux and performance in one catalytic cycle; and (d) represents the stress-strain curve of the aerogel from Example 1. Table 1 presents the porosity, density, and water flux data for different aerogel catalysts.

[0061] Table 1. Porosity, density, and water flux results of different aerogel catalysts

[0062] like Figure 5 As shown in (a), by measuring the residual concentration rate and removal rate of ciprofloxacin degradation by PMS activated by aerogel, it was found that compared with other aerogel materials, the CoMn-LDHs / SA / DC of the present invention has the best effect on the degradation of ciprofloxacin by activated PMS, achieving a removal rate of 48.8% in 2 minutes.

[0063] Figure 5 (b) and (c) show the test results for density, porosity, water flux, and degradation rate after one filtration for different aerogels, respectively. Further, combined with Table 1, it can be seen that the density of CoMn-LDHs / SA alone is 0.1163 g / cm³. 3 The porosity was 70.38%, and the CoMn-LDHs / SA exhibited the highest water flux, reaching 6306.6 L / (m²). 2 •h). Water flux and porosity are positively correlated, but excessive water flux leads to a short residence time of ciprofloxacin wastewater combined with PMS in the CoMn-LDHs / SA aerogel. This results in insufficient catalyst activation of PMS, leading to a removal rate of only 44% per cycle. The density of the CoMn-LDHs / SA / CMC aerogel material is 0.2454 g / cm³. 3The porosity is 34.69%, and the water flux is relatively low, reaching 1533.87 L / (m²). 2 •h), the catalyst can fully activate PMS, resulting in a removal rate of 64.6% per cycle. The density of CoMn-LDHs / SA / DC is 0.1374 g / cm³. 3 The porosity is 62.74%, and the water flux is lower than that of CoMn-LDHs / SA, reaching 4041.22 L / (m²). 2 •h), the catalyst can fully activate PMS, resulting in a removal rate of 72.15% per cycle. The density of CoMn-LDHs / SA / CMC / DC is 0.2311 g / cm³. 3 The porosity is 59.0%, and the water flux is lower than that of CoMn-LDHs / SA / CMC, reaching 1183.08 L / (m³). 2 •h). It is evident that the introduction of short cotton fibers increases the porosity of the porous material while decreasing its density. Compared to sodium alginate alone, the density increases slightly. The introduction of carboxymethyl cellulose makes the porous material more compact. However, this denser pore structure hinders water permeability. The introduction of carboxymethyl cellulose significantly reduces the water flow rate in the porous aerogel, allowing the catalyst to effectively bind with PMS and ensuring a complete catalytic reaction. Furthermore, the introduction of short cotton fibers increases the water flux from 6306.60 L / (m²). 2 •h) decreased to 4041.22L / (m 2 •h), indicating that it ensures both an appropriate residence time of wastewater in the aerogel and maintains high water permeability. This demonstrates that the introduction of short cotton fibers, while ensuring high porosity, keeps the water flux within a suitable range, ensuring the catalyst can fully activate PMS, thus achieving excellent catalytic degradation. Considering both ensuring the catalytic reaction proceeds fully and improving catalytic efficiency, CoMn-LDHs / SA / DC was determined to be the catalytic material with the best performance.

[0064] Figure 5 In Figure (d), the stress-strain curves of the CoMn-LDHs / SA / DC aerogel are shown when the maximum deformation is 20%, 40%, 60%, and 80%, respectively. It can be seen that the CoMn-LDHs / SA / DC aerogel has good lateral deformation recovery ability. Furthermore, this invention compares the aerogel material of Example 1 with the aerogel materials prepared in Comparative Examples 1-3, and finds that the CoMn-LDHs / SA / DC aerogel has the best deformation recovery ability.

[0065] Experimental Example 4: Catalytic Performance Testing of CoMn-LDHs Materials in Advanced Oxidation (1) Effects of PMS, pH and catalyst concentration on the activation performance of CoMn-LDHs catalyst on PMS To evaluate the catalytic performance of the CoMn-LDHs material in Example 1 as a catalyst in an advanced oxidation process, ciprofloxacin (CIP) was selected as the target pollutant, and degradation experiments were conducted under initial pH and 25°C conditions. The specific reaction conditions were: wastewater volume 100 mL, catalyst = 0.05 g / L, PMS = 0.75 mM, initial pH 6.69, and CIP = 10 mg / L. During the experiment, 10 mg of CoMn-LDHs was added, and the CoMn-LDHs were loaded onto PVDF to obtain a CoMn-LDHs / PVDF composite membrane (composite membrane thickness 0.5 mm, size 2 × 2 cm). 2 It is used for the adsorption and degradation treatment of wastewater.

[0066] Figure 6 The results show the catalytic performance of the CoMn-LDHs material in Example 1 under different conditions: with / without PMS, different pH, and different catalyst concentrations. Among them, (a) shows the effect of adding / without adding PMS on CIP degradation, (b) shows the catalytic performance evaluation of CoMn-LDHs, and (c) and (d) show the effects of different pH and different catalyst concentrations on CIP degradation, respectively.

[0067] like Figure 6 As shown in (a), when only CoMn-LDHs are added without the persulfate (PMS) activator, the CIP removal rate is only 10.3% within 20 min, indicating that the physical adsorption effect of the material itself on CIP is negligible. Similarly, when 0.75 mM PMS is added alone without a catalyst, only 9% of CIP is removed in the same reaction time, mainly due to the limited oxidation capacity of PMS itself. However, when CoMn-LDHs and PMS are added simultaneously to form a synergistic system, the reaction system exhibits a significant catalytic activation effect, achieving an 85.3% CIP degradation rate within the first 2 min of the reaction. This rapid reaction kinetics is due to the abundant exposure of active sites on the catalyst surface and efficient electron transfer.

[0068] To systematically investigate the effects of catalyst dosage and persulfate (PMS) concentration on the degradation process of ciprofloxacin (CIP), this invention constructed a multidimensional reaction system through a bivariate crossover experimental design. The results are as follows: Figure 6As shown in (b) of the figure. With fixed reaction conditions of pH = 7.0 ± 0.2, 25℃, and an initial CIP concentration of 10 mg / L, 16 experimental groups were conducted to compare the dynamic efficiency of CoMn-LDHs catalysts with addition gradients (0.05, 0.1, 0.15, 0.2 g / L) and PMS concentration gradients (0.5, 0.75, 1.0, 1.25 mM). Experimental data showed that when the PMS concentration increased from 0.5 mM to 1.25 mM, the CIP degradation efficiency of each catalyst group showed a significant increase. In particular, under the synergistic effect of 0.15 g / L catalyst and 1.25 mM PMS, the system achieved a CIP removal rate of 96.7% within 20 min, which was improved compared to the 0.5 mM PMS system, confirming that moderately increasing the oxidant concentration can effectively enhance the intensity of free radical generation. Considering the economic cost of practical application, a dosage of 0.05 g / L CoMn-LDHs and 0.75 mM PMS was selected for subsequent experiments.

[0069] To investigate the effect of solution pH on the degradation efficiency of ciprofloxacin (CIP) in the CoMn-LDHs / PMS system, this invention systematically examined the pollutant removal patterns within the pH range of 3-11, such as... Figure 6 As shown in (c), under strongly acidic conditions (pH=3), the degradation efficiency of CIP was significantly limited, with a removal rate of only 67.8% after 20 minutes. This was mainly attributed to excessive H+. + By protonating the active sites on the catalyst surface, the adsorption and activation process of PMS at Co / Mn sites is inhibited. When the solution pH is increased to the range of 5-11, the system exhibits excellent versatility, with the CIP degradation rate remaining above 84%. In the original CIP solution without pH adjustment (pH=6.69), the removal rate reaches a peak of 94% after 20 minutes. Under near-neutral conditions, the hydroxyl groups (-OH) on the catalyst surface and PMS significantly accelerate the generation of singlet oxygen and surface-bound free radicals through hydrogen bonding. The catalyst surface becomes positively charged under acidic conditions and negatively charged under alkaline conditions. When pH < 5 or pH > 9, the catalyst surface and PMS are repelled by the same charge, reducing the contact between them and leading to a decrease in free radical generation, which in turn reduces the CIP removal rate. In addition, it may also be due to the self-decomposition of PMS under alkaline conditions. Therefore, this invention ultimately establishes 0.05 g / L CoMn-LDHs, 0.75 mM PMS, 25 °C, and the original pH=6.69 as the optimal reaction parameters.

[0070] To evaluate the applicability of the CoMn-LDHs / PMS system in practical wastewater treatment, this invention systematically investigated the effect of initial ciprofloxacin (CIP) concentrations (10–80 mg / L) on degradation kinetics under optimized reaction conditions (0.05 g / L catalyst, 0.75 mM PMS, pH = 6.69, 25 °C). Figure 6 As shown in (d), when the CIP concentration increased from 20 mg / L to 80 mg / L, the degradation efficiency at 20 min showed a gradient decreasing trend, reaching 87%, 84%, 68%, and 58%, respectively. Notably, the system exhibited excellent treatment efficiency (degradation rate >84%) at concentrations of 30 mg / L and below. However, when the CIP concentration exceeded 50 mg / L, the degradation efficiency significantly decreased to 68%. At 20 min, high-performance liquid chromatography (HPLC) analysis revealed a CIP degradation efficiency of 95.86%, indicating that the system has broad applicability to CIP antibiotics.

[0071] (2) Effects of reaction temperature and catalyst stability on the activation performance of CoMn-LDHs catalyst for PMS Furthermore, this invention investigates the effect of CoMn-LDHs on the CIP degradation process by setting different reaction temperatures (15℃, 20℃, 25℃, and 30℃). The reaction conditions were: catalyst = 0.05 g / L, PMS = 0.75 mM, initial pH (6.69), and CIP = 10 mg / L. Meanwhile, the stability and reusability of the catalyst are important indicators for evaluating its performance. Therefore, under constant reaction conditions, four repeated experiments were conducted with a 20-minute cycle. After each experimental cycle, the catalyst was recovered by centrifugation and washed three times alternately with anhydrous ethanol and ultrapure water, and finally dried in an oven at 60℃ for use in the next experimental cycle. To evaluate the reusability of the existing catalyst, further catalyst recycling experiments were conducted. Finally, tap water and lake water were used as test matrices to evaluate the performance of the catalytic material.

[0072] Figure 7 The results show the catalytic performance and cycle performance of the CoMn-LDHs material in Example 1 at different reaction temperatures; where (a) represents the degradation performance at different temperatures (15-30℃), (b) to (c) represent the cycle performance evaluation of the catalyst, and (d) represents the degradation performance under different water qualities.

[0073] like Figure 7As shown in (a), the time required for complete CIP degradation decreases sequentially with increasing temperature. This is because as the temperature increases, the chances of PMS molecules colliding with the active sites of the catalyst increase, generating more active free radicals and accelerating the degradation of CIP.

[0074] The residual concentration rate after 4 cycles is as follows Figure 7 As shown in (b) of the figure, the degradation efficiency of CIP in the recycling test is as follows: Figure 7 As shown in (c), after 4 cycles, the degradation efficiency of CIP still reached 77.9%, and the slight decrease in degradation efficiency was mainly attributed to the loss of catalyst during the cycle.

[0075] In addition, such as Figure 7 As shown in (d), the CoMn-LDHs and PMS system exhibited excellent degradation efficiency in removing CIP from various aquatic matrices, including tap water and river water (Jialu River). This demonstrates that the CoMn-LDH catalyst has good adaptability to complex aquatic environments.

[0076] (3) Effects of anions and organic matter on the activation performance of CoMn-LDHs catalysts for PMS This invention further explores several common anions in wastewater, including NO3-. − Cl − H2PO4 − and HCO3 - The effects of 5 mmol / L catalyst and representative natural organic compound humic acid (HA) on the activation performance of CoMn-LDHs catalysts on PMS were investigated. The specific reaction conditions were: catalyst = 0.05 g / L, PMS = 0.75 mM, initial pH = 6.69, and CIP = 10 mg / L.

[0077] The effects of different anions and organic compounds on the activated PMS degradation of CoMn-LDHs materials in Example 1 are as follows: Figure 8 As shown; (a) shows the effect of different anions on the degradation effect, and (b) shows the effect of organic matter HA on the degradation effect.

[0078] like Figure 8 As shown in (a), anions inhibited the degradation of CIP to varying degrees. Specifically, NO3- − The impact on CIP degradation efficiency was minimal, with a residual concentration of 9.31%, due to NO3. − With SO4• － The reaction rate constant is low. Cl − The degradation efficiency of pollutants in the SR-AOPs system is quite complex. In the CoMn-LDHs / PMS system, Cl... −It also showed an inhibitory effect on the degradation of CIP, with a residual concentration of 28.27%. HCO3 - and Cl − Similarly, both can be combined with SO4• − It reacts with HO•, producing chlorine free radicals with low activity. HCO3 - The degradation efficiency of CIP was significantly affected, with a residual concentration of 70.73%. This result may be due to HCO3. - With SO4• − The reaction with H₂O• consumes some free radicals, and the resulting carbonate free radicals have a low redox potential (1.63 eV) and low reactivity with most organic pollutants. H₂PO₄ − The degradation efficiency of CIP was significantly affected, with a residual concentration of 34.09% and H2PO4. − Can be combined with SO4• － The reaction produces HPO4•, which has even lower oxidizing power. － and H2PO4• - Therefore, it can be seen that the influence of coexisting anions on the CoMn-LDHs / PMS system in actual wastewater treatment, from largest to smallest, is HCO3-. − >H2PO4 − >Cl − >NO3 − .

[0079] In addition, such as Figure 8 As shown in (b), humic acid, a natural organic compound, exhibits good resistance to interference in the catalytic degradation of CoMn-LDHs, achieving a removal rate of 73.4% for a 10 mg / L CIP solution. This phenomenon is mainly caused by the following two factors: firstly, NaHA adsorbs onto the catalyst surface, reducing the number of active sites; secondly, it competes with ciprofloxacin for active free radicals, further reducing the number of active free radicals.

[0080] (4) Effect of different antibiotics on the activation performance of CoMn-LDHs catalysts on PMS Under the aforementioned optimal reaction conditions, this invention investigated the effects of different antibiotics (ciprofloxacin, norfloxacin, and ofloxacin) on the activation performance of CoMn-LDHs catalysts on PMS. The specific reaction conditions were: catalyst = 0.05 g / L, PMS = 0.75 mM, initial pH 6.69, antibiotic = 10 mg / L, and other conditions as described above.

[0081] Figure 9The results show the spectral scanning results of different antibiotic systems and the removal rates of different antibiotics; where (a) to (c) are the spectral scanning results of ciprofloxacin, norfloxacin, and ofloxacin at different reaction times, respectively, and (d) is the removal rate result of different antibiotics.

[0082] Depend on Figure 9 As shown in (a) to (d), compared to ciprofloxacin, the CoMn-LDHs / PMS system also exhibits excellent degradation performance for norfloxacin and ofloxacin. The maximum absorption characteristic peaks of the three antibiotics are significantly reduced or disappear, and the degradation efficiency reaches almost 90% or more within 2 minutes. Therefore, due to the high catalytic activity of CoMn-LDHs, CoMn-LDHs can effectively activate PMS and degrade other pollutants.

[0083] Experimental Example 5: Catalytic Performance Testing of CoMn-LDHs / SA / DC Materials in Advanced Oxidation The above confirms the catalytic performance of CoMn-LDHs in advanced oxidation processes. However, as a powder catalyst, CoMn-LDHs is difficult to directly separate and recover from the reaction system after use, limiting its practical application. Therefore, this invention further verifies the catalytic degradation performance of the CoMn-LDHs / SA / DC material prepared in Example 1 for antibiotics in advanced oxidation processes.

[0084] (1) Effects of PMS, temperature, pH and catalyst concentration on the catalytic activation performance of CoMn-LDHs / SA / DC materials on PMS To evaluate the catalytic performance of the CoMn-LDHs / SA / DC aerogel material of Example 1 in an advanced oxidation process, the antibiotic ciprofloxacin (CIP) was selected as the target pollutant, and degradation experiments were conducted under initial pH and 25°C conditions. The degradation process did not require additional light and was carried out directly under natural light. Degradation was performed by pouring the prepared antibiotic wastewater into a burette containing the aerogel. The reaction conditions were: aerogel material diameter 27 mm, thickness 30 mm, PMS = 0.75 mM, initial pH (6.69), and CIP = 10 mg / L.

[0085] Figure 10 The results of the catalytic performance evaluation of CoMn-LDHs / SA / DC aerogel materials are as follows: (a) catalytic performance of the materials with / without PMS; (b) catalytic performance at different reaction temperatures; (c) catalytic performance at different pH values; and (d) catalytic performance at different CoMn-LDHs / SA / DC concentrations. Figure 10In (a), SA+DC is the aerogel group of Comparative Example 4, PMS is the control group with only PMS solution added, SA+DC+PMS is the combined aerogel and PMS group of Comparative Example 4, and SA+DC+LDH+PMS is the combined aerogel and PMS group of Example 1.

[0086] like Figure 10 As shown in (a), the adsorption experiment of antibiotic wastewater using aerogel with only SA / DC added (Comparative Example 4) showed a removal rate of only 19.78% after 20 min, indicating that SA / DC without CoMn-LDHs had no catalytic effect on persulfate (PMS), which is attributed to the adsorption effect of porous aerogel on ciprofloxacin. Similarly, when 0.75 mM PMS was added alone without a catalyst, CIP was only removed by 9% in the same reaction time, mainly due to the limited oxidation capacity of PMS itself. However, when CoMn-LDHs / SA / DC formed a synergistic system with PMS (i.e., SA+DC+LDH+PMS), the reaction system exhibited a significant catalytic activation effect, achieving a CIP degradation rate of 48.9% within the first 2 min of the reaction. This rapid reaction kinetics is due to the abundant exposure of active sites on the catalyst surface and efficient electron transfer. After 20 min, the catalytic reaction basically reached equilibrium, and the CIP degradation rate reached 82.3%. Therefore, it can be seen that CoMn-LDHs / SA / DC aerogel has a significant catalytic activation effect on PMS. This invention achieves efficient removal of ciprofloxacin through the synergistic effect of the adsorption of porous aerogel and the catalytic effect of CoMn-LDHs.

[0087] Furthermore, this invention investigates the effect of different reaction temperatures (15°C, 20°C, 25°C, and 30°C) on the CIP degradation process. Figure 10 As shown in (b), the time required for CIP degradation to reach equilibrium decreases sequentially with increasing temperature. This is because as temperature increases, the chances of PMS molecules colliding with the active sites of the catalyst increase, generating more active free radicals and accelerating CIP degradation.

[0088] To investigate the effect of solution pH on the degradation efficiency of ciprofloxacin (CIP) in the CoMn-LDHs / PMS system, this invention systematically examined the pollutant removal behavior within a pH range of 3-11, such as... Figure 10 As shown in (c), under strongly acidic conditions (pH=3), the degradation efficiency of CIP is significantly limited, with a removal rate of only 69.35% after 20 minutes. When the solution pH is increased to the range of 5-11, the system exhibits excellent adaptability, with the CIP degradation rate remaining above 72%. In the original CIP solution without pH adjustment (pH=6.69), the removal rate reaches a peak of 82.28% after 20 minutes.

[0089] To evaluate the applicability of the CoMn-LDHs / SA / DC and PMS system in practical wastewater treatment, the effects of ciprofloxacin (CIP) at different initial concentrations (10-80 mg / L) on degradation kinetics were systematically investigated. Figure 10 As shown in (d), when the CIP concentration increased from 20 mg / L to 80 mg / L, the degradation efficiency after 20 min showed a gradient decreasing trend, reaching 76.92%, 71.90%, 69.69%, and 67.37%, respectively. Therefore, it is confirmed that CoMn-LDHs / SA / DC catalytic aerogel can effectively activate PMS to degrade pollutants.

[0090] (2) Single-pass water permeability catalytic performance and cycle stability of CoMn-LDHs / SA / DC materials Single-pass water permeability catalytic performance testing is also an important indicator for evaluating the performance of catalytic membranes. This invention evaluates the single-pass water permeability catalytic performance of CoMn-LDHs / SA / DC materials. Furthermore, reusability is an important criterion for evaluating catalysts, reflecting not only their stability but also cost control in various degradation methods. The CoMn-LDHs / SA / DC aerogel after CIP degradation was washed three times with anhydrous ethanol and deionized water. Under conditions of 20 min adsorption time, a catalytic aerogel diameter of 27 mm and a thickness of 3 cm, a PMS addition of 0.75 mM, and initial pH, the recovered material was directly reused in degradation experiments without centrifugation to test its cyclic degradation performance, with four cycles. Finally, tap water and lake water were used as test matrices, and the performance was compared with deionized water (DI water) to evaluate the usability of the catalytic material. The degradation reaction conditions were as follows: aerogel material diameter 27 mm, thickness 30 mm, PMS = 0.75 mM, initial pH (6.69), CIP = 10 mg / L.

[0091] Figure 11 The study evaluates the single-pass catalytic performance, cycle stability, and degradation effect of CoMn-LDHs / SA / DC under optimal conditions, as well as the degradation effect in different water qualities. Among them, (a) shows the single-pass catalytic performance of CoMn-LDHs / SA / DC, (b) to (c) show the cycle performance evaluation, and (d) shows the degradation performance in different water qualities.

[0092] like Figure 11 As shown in (a), the antibiotic solution can achieve a CIP removal rate of 73% after one pass through CoMn-LDHs / SA / DC, and almost reaches catalytic equilibrium after the fourth pass.

[0093] from Figure 11As can be seen from (b) to (c), when the catalyst is reused 1 to 4 times, the degradation rates of CIP are 83.91%, 81.01%, 74.45% and 70.92%, respectively, which indicates that the catalyst has excellent stability and reusability.

[0094] In addition, such as Figure 11 As shown in (d), the co-doped CoMn-LDHs / SA / DC and PMS system exhibit excellent degradation efficiency in removing CIP from various aquatic matrices, including tap water and river water (Jialu River). This demonstrates that the CoMn-LDHs / SA / DC catalytic aerogel is well-adapted to complex aquatic environments.

[0095] In summary, this invention prepared sea urchin-like CoMn-LDHs via a hydrothermal method, which effectively activated PMS and degraded CIP within a wide pH range (3.0–11.0). Furthermore, this invention utilizes a plate casting combined with PMS-based water treatment technology to load CoMn-LDHs nanoparticles onto short-fiber sodium alginate aerogel, preparing a CoMn-LDHs / SA / DC aerogel catalytic material. This material serves as a membrane-structured catalytic support, achieving a ciprofloxacin removal efficiency of 82.3%. Simultaneously, this aerogel catalytic material exhibits high hydrophilicity, porosity, and optimal pore size and water flux, demonstrating high catalytic degradation efficiency. Moreover, even after prolonged filtration cycles, the aerogel material maintains a high antibiotic removal rate, highlighting its practical applicability.

[0096] Therefore, this invention provides an innovative and promising solution for improving the removal of new pollutants, water permeability, and durability in advanced water treatment processes using CoMn-LDHs / SA / DC catalytic materials. It solves the problems of difficult separation of powdered catalysts and the difficulty in balancing the mechanical properties of aerogels with water flux. It has broad application prospects in the field of antibiotic wastewater treatment and also has important guiding value for the development of catalytic materials for water treatment.

Claims

1. A method for preparing an aerogel material of CoMn-LDHs encapsulated with sodium alginate-loaded short cotton fibers, characterized in that, Includes the following steps: (1) Dissolve sodium alginate in water to obtain sodium alginate solution; add CoMn-LDHs nanoparticles and short cotton fibers to the sodium alginate solution and stir evenly to obtain a mixed dispersion; (2) The mixed dispersion is freeze-formed and then freeze-dried to obtain a nascent gel; (3) The initial aerogel is immersed in a calcium ion solution for cross-linking treatment, and then the cross-linked aerogel is freeze-dried to obtain the sodium alginate-loaded short cotton wool-encapsulated CoMn-LDHs aerogel material.

2. The method for preparing the aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to claim 1, characterized in that, In step (1), the concentration of the sodium alginate solution is 3%~5%m / V; the dissolution temperature is 70~90℃; and the fiber length of the short cotton linter is 5~10mm.

3. The method for preparing the aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to claim 1, characterized in that, In step (1), the preparation method of the CoMn-LDHs nanoparticles includes the following steps: using cobalt salt and manganese salt as metal sources, and triethanolamine and urea as dual alkali sources; mixing cobalt salt, manganese salt, triethanolamine and urea in water until uniform, and then hydrothermally reacting at 100~140℃ for 1~4h; washing, drying, grinding and sieving the obtained reaction product to obtain the CoMn-LDHs nanoparticles.

4. The method for preparing the aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to claim 3, characterized in that, The cobalt salt is cobalt nitrate hexahydrate; the manganese salt is manganese nitrate tetrahydrate; the molar ratio of the cobalt salt to the manganese salt is 1:(0.8~1.2); the molar ratio of the triethanolamine to urea is 1:(1.8~2.2).

5. The method for preparing the aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to any one of claims 1 to 3, characterized in that, In steps (2) and (3), the freeze-drying process is carried out at a temperature of -30 to -20°C for 20 to 30 hours.

6. The method for preparing the aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to any one of claims 1 to 3, characterized in that, In step (3), the calcium ion solution is a calcium chloride solution; the concentration of the calcium chloride solution is 2wt%~5wt%; and the crosslinking treatment time is 4~8h.

7. An aerogel material containing sodium alginate-loaded short cotton fibers encapsulating CoMn-LDHs, prepared by the method described in any one of claims 1 to 6, characterized in that, The aerogel material includes CoMn-LDHs nanoparticles and a sodium alginate aerogel matrix; the CoMn-LDHs nanoparticles are loaded in the sodium alginate aerogel matrix; short cotton fibers are also dispersed in the sodium alginate aerogel matrix as a skeletal support material.

8. The aerogel material of CoMn-LDHs encapsulated with sodium alginate-supported short cotton fibers according to claim 7, characterized in that, The CoMn-LDHs nanoparticles have a sea urchin-like morphology and are composed of stacked needle-like particles; the aerogel material has a layered porous structure containing interconnected pores and channels arranged perpendicularly along the growth direction.

9. The application of an aerogel material containing sodium alginate-supported short cotton fibers encapsulated with CoMn-LDHs as described in claim 7, characterized in that, Application as a catalyst in the activation of persulfate degradation in antibiotic-containing wastewater.

10. The application of the sodium alginate-supported short cotton lint-encapsulated CoMn-LDHs aerogel material according to claim 9, characterized in that, The antibiotic is selected from one or more of ciprofloxacin, norfloxacin, and ofloxacin; the pH range of the degradation is 3 to 11; the degradation is carried out under conditions without external light; the concentration of the added persulfate is 0.5 to 1.25 mM.

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