Immobilized carrier material used for water treatment and used for immobilizing microorganisms and preparation method of immobilized carrier material

Abstract

The invention relates to the technical field of water treatment, in particular to an immobilized carrier material used for water treatment and used for immobilizing microorganisms and a preparation method of the immobilized carrier material, and the main technical scheme is as follows: the immobilized carrier material comprises a porous Co-Cr-Mo alloy skeleton and a biological activating coating; wherein the porosity of the porous Co-Cr-Mo alloy framework is 60%-80%, the average pore size is 100-500 microns, and the surface of the porous Co-Cr-Mo alloy framework is of a micron-sized dendritic crystal structure; the biological activation coating is a Ca / P-containing oxide layer generated on the surface of the alloy through plasma electrolytic oxidation, the thickness of the coating is 18-50 microns, and a polydopamine-chitosan compound is grafted on the surface of the coating. Through the collaborative design of the porous Co-Cr-Mo alloy skeleton and the functional bioactive coating, and in combination with plasma electrolytic oxidation and polydopamine-chitosan composite grafting technologies, efficient immobilization and activity maintenance of microorganisms are realized, and meanwhile, the carrier is endowed with conductivity and catalytic degradation capability, so that the water treatment performance is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to an immobilized carrier material for water treatment and its preparation method. Background Art

[0002] With rapid industrialization and urbanization, water pollution has become increasingly serious, especially the discharge of recalcitrant organic pollutants and heavy metal ions, which pose a severe threat to the ecological environment and human health. Microbial immobilization technology, due to its high efficiency, stability, and environmental friendliness, shows broad application prospects in the field of water treatment. However, traditional immobilization carriers (such as activated carbon, polymer gels, and ceramic materials) generally suffer from low mechanical strength, insufficient microbial loading, poor mass transfer efficiency, and poor biocompatibility, limiting their large-scale application.

[0003] In recent years, porous metal materials have gradually become a research hotspot for microbial immobilization carriers due to their high specific surface area, excellent mechanical properties, and good mass transfer characteristics. However, the surfaces of conventional porous metals (such as stainless steel and titanium alloys) lack biological activity, making it difficult to effectively promote the attachment and growth of microorganisms. In addition, coatings formed by simple surface modification (such as chemical plating and anodizing) in existing technologies often have defects such as weak adhesion and limited functionality, failing to simultaneously meet the requirements of microbial immobilization, electron transfer, and long-term stability.

[0004] Plasma electrolytic oxidation (PEO) technology can form porous oxide coatings on metal surfaces, significantly improving their biocompatibility. However, traditional PEO coatings still suffer from insufficient porosity and limited active sites in microbial immobilization applications. Furthermore, existing immobilization carriers are susceptible to pollutant toxicity or changes in redox conditions in complex water environments, leading to decreased microbial activity and reduced treatment efficiency. Therefore, developing a microbial immobilization carrier material that combines high porosity, excellent biocompatibility, conductivity, and catalytic activity is of great significance for improving water treatment efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide an immobilized carrier material for water treatment and its preparation method. Through the synergistic design of a porous Co-Cr-Mo alloy framework and a functionalized bio-activating coating, combined with plasma electrolytic oxidation and polydopamine-chitosan composite grafting technology, efficient immobilization and activity maintenance of microorganisms are achieved, while the carrier is endowed with conductivity and catalytic degradation ability, significantly improving water treatment performance.

[0006] The present invention provides an immobilization carrier material for water treatment, comprising a porous Co-Cr-Mo alloy framework and a bio-activated coating;

[0007] Among them, the porous Co-Cr-Mo alloy skeleton has a porosity of 60%-80%, an average pore size of 100-500μm, and a micron-scale dendritic structure on its surface.

[0008] The bio-activated coating is a Ca / P oxide layer generated on the alloy surface by plasma electrolytic oxidation. The coating thickness is 18-50μm, and the surface is grafted with polydopamine-chitosan complex.

[0009] Furthermore, calculated by mass percentage, the composition of the Co-Cr-Mo alloy is: Co 60-65wt%, Cr 28-32wt%, Mo 5-7wt%, and 0.1-0.5wt% of Y2O3 nanoparticles as a dispersed reinforcing phase.

[0010] Furthermore, the microstructure of the bio-activated coating from the outside in includes:

[0011] Nanoflower-like CaHPO4·2H2O crystal layers with crystal sizes of 50-200 nm; amorphous Co3(PO4)2 porous layers and Cr2O3 transition layers.

[0012] Furthermore, the thickness of the nano-flower-like CaHPO4·2H2O crystal layer is 5-8 μm; the thickness of the amorphous Co3(PO4)2 porous layer is 10-15 μm; and the thickness of the Cr2O3 transition layer is 2-3 μm.

[0013] Furthermore, conductive polyaniline nanowires and zero-valent iron nanoparticles are embedded in the polydopamine-chitosan complex.

[0014] Furthermore, the conductive polyaniline nanowires have a diameter of 20-30 nm and a length of 1-5 μm.

[0015] Furthermore, the particle size of the zero-valent iron nanoparticles is 10-20 nm.

[0016] The present invention also provides a method for preparing an immobilized carrier material for water treatment and immobilizing microorganisms, comprising the following steps:

[0017] Preparation of porous Co-Cr-Mo alloy framework: Selective laser melting technology was used to prepare a porous Co-Cr-Mo alloy framework with a porosity of 60%-80% and an average pore size of 100-500μm under a protective atmosphere, with laser power controlled at 150-300W, scanning speed at 600-1200mm / s, and layer thickness at 30-50μm. This yielded a matrix with a micron-scale dendritic structure on the surface.

[0018] Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo alloy framework as the anode, plasma electrolytic oxidation is carried out in an electrolyte containing calcium salts and phosphates. The electrolyte pH is 8-11, and the current density is 5-15 A / dm³. 2 The processing time is 10-30 minutes, forming a Ca / P-containing oxide layer on the alloy surface, and obtaining a composite coating consisting of a nano-flower-like CaHPO4·2H2O crystal layer, an amorphous Co3(PO4)2 porous layer and a Cr2O3 transition layer from the outside to the inside, with a total coating thickness of 10-50 μm.

[0019] Grafting of polydopamine-chitosan composite: Immerse in a Tris-HCl buffer solution containing dopamine and chitosan, and simultaneously add conductive polyaniline nanowires and zero-valent iron nanoparticles. React at pH 8.5 and 25-37℃ for 12-24 hours to graft the polydopamine-chitosan composite with the conductive polyaniline nanowires and zero-valent iron nanoparticles onto the coating surface, forming a bio-activated composite coating.

[0020] Furthermore, the calcium salt is calcium acetate or calcium nitrate, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate, and the Ca / P molar ratio in the electrolyte is 1.5-2.0:1.

[0021] Furthermore, the dopamine concentration was 1-3 mg / mL, the chitosan concentration was 0.5-2 wt%, and the amount of conductive polyaniline nanowires added was 0.1-0.5 mg / cm² of the coating surface area. 2 The amount of zero-valent iron nanoparticles added is 0.05-0.2 mg / cm² of the coating surface area. 2 .

[0022] In summary, the present invention has the following beneficial effects:

[0023] This invention utilizes selective laser melting (SLM) to prepare a porous Co-Cr-Mo alloy framework (porosity 60%-80%, average pore size 100-500 μm) exhibiting excellent mechanical strength and mass transfer properties. A Ca / P oxide bio-activated coating (18-50 μm thick) constructed on the surface via plasma electrolytic oxidation significantly enhances the material's biocompatibility. Conductive polyaniline nanowires and zero-valent iron nanoparticles embedded in the surface-grafted polydopamine-chitosan composite not only enhance microbial immobilization but also endow the material with excellent electron transport and catalytic degradation performance. This carrier material integrates a high-porosity structure, good biocompatibility, efficient electron transport, and catalytic function, significantly improving microbial loading and pollutant degradation efficiency. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation method, features and effects of a purification method for testosterone heptanate proposed according to the present invention are described in detail below.

[0025] Plasma electrolytic oxidation (PEO) technology can form porous oxide coatings on metal surfaces, significantly improving their biocompatibility. However, traditional PEO coatings still suffer from insufficient porosity and limited active sites in microbial immobilization applications. Furthermore, existing immobilization carriers are susceptible to pollutant toxicity or changes in redox conditions in complex water environments, leading to decreased microbial activity and reduced treatment efficiency. Therefore, developing a microbial immobilization carrier material that combines high porosity, excellent biocompatibility, conductivity, and catalytic activity is of great significance for improving water treatment efficiency.

[0026] To address the aforementioned issues, this specific embodiment proposes a novel immobilization carrier material. Through the synergistic design of a porous Co-Cr-Mo alloy framework and a functionalized bio-activating coating, combined with plasma electrolytic oxidation and polydopamine-chitosan composite grafting technology, efficient immobilization and activity maintenance of microorganisms are achieved. At the same time, the carrier is endowed with conductivity and catalytic degradation capabilities, significantly improving water treatment performance.

[0027] This specific embodiment provides an immobilization carrier material for water treatment, which includes a porous Co-Cr-Mo alloy framework and a bio-activated coating.

[0028] Among them, the porous Co-Cr-Mo alloy skeleton has a porosity of 60%-80%, an average pore size of 100-500μm, and a micron-scale dendritic structure on its surface.

[0029] The bio-activated coating is a Ca / P oxide layer generated on the alloy surface by plasma electrolytic oxidation. The coating thickness is 18-50μm, and the surface is grafted with polydopamine-chitosan complex.

[0030] It is understood that the immobilization carrier material provided in this specific embodiment, through a porous Co-Cr-Mo alloy framework, offers high porosity (60%-80%) and a micron-scale dendritic surface structure, creating an ideal physical environment for microbial attachment. Simultaneously, a Ca / P-containing oxide bio-activating coating (18-50 μm) is constructed on the framework surface using plasma electrolytic oxidation technology. The special components of this coating (including a nano-flower-like CaHPO4·2H2O crystal layer, an amorphous Co3(PO4)2 porous layer, and a Cr2O3 transition layer) significantly enhance the material's biocompatibility. Finally, by grafting a polydopamine-chitosan composite onto the surface and embedding conductive polyaniline nanowires and zero-valent iron nanoparticles, not only is the microbial immobilization effect enhanced, but the material also possesses excellent electron transport capabilities and catalytic degradation performance. This multi-level structural design enables the carrier material to simultaneously possess excellent mechanical strength, high microbial loading capacity, good biocompatibility, and efficient pollutant degradation capabilities, significantly improving water treatment efficiency and service life.

[0031] In some preferred embodiments, the Co-Cr-Mo phase comprises, by mass percentage, 60-65 wt% Co, 28-32 wt% Cr, 5-7 wt% Mo, and 0.1-0.5 wt% Y2O3 nanoparticles as a dispersed reinforcing phase.

[0032] Understandably, a Co-Cr-Mo alloy with a specific composition ratio (Co 60-65wt%, Cr 28-32wt%, Mo 5-7wt%) is used, with 0.1-0.5wt% Y₂O₃ nanoparticles added as a dispersed reinforcing phase. This alloy composition design has multiple advantages: First, the Co-Cr-Mo ternary system provides excellent corrosion resistance and mechanical strength, where Co ensures good toughness of the matrix, Cr imparts excellent corrosion resistance, and Mo further enhances the alloy's stability in harsh aquatic environments. Second, the added Y₂O₃ nanoparticles, as a dispersed reinforcing phase, can effectively refine grains and pin dislocation movement, significantly improving the alloy's mechanical properties and fatigue resistance, while not affecting the formability of its porous structure. This optimized alloy composition not only ensures the structural stability of the carrier skeleton in long-term water treatment applications but also enables the material to withstand greater hydraulic loads and mechanical impacts through the reinforcing effect of Y₂O₃ nanoparticles, greatly extending its service life.

[0033] In some preferred embodiments, the microstructure of the bio-activated coating from the outside in includes:

[0034] Nanoflower-like CaHPO4·2H2O crystal layers with crystal sizes of 50-200 nm; amorphous Co3(PO4)2 porous layers and Cr2O3 transition layers.

[0035] Understandably, the unique multilayer structure design of the bio-activated coating has a synergistic effect: the outermost nano-flower-like CaHPO4·2H2O crystal layer (50-200nm) has an ultra-high specific surface area and abundant active sites, and its special nano-flower morphology can significantly enhance the initial adhesion ability of microorganisms; the middle amorphous Co3(PO4)2 porous layer has a uniform nanopore structure, which can promote nutrient transport and provide an ideal microenvironment for microbial growth; the innermost Cr2O3 transition layer forms a chemical bond with the alloy matrix, ensuring the strong bonding of the coating. This gradient structure design realizes the functional integration of "external bioactivity - middle mass transfer channel - internal strong bonding", which not only greatly improves the loading density and activity of microorganisms, but also ensures the stability of the coating under long-term water erosion, making the carrier material have both excellent biocompatibility and durability.

[0036] In some preferred embodiments, the thickness of the nanoflower-like CaHPO4·2H2O crystal layer is 5-8 μm; the thickness of the amorphous Co3(PO4)2 porous layer is 10-15 μm; and the thickness of the Cr2O3 transition layer is 2-3 μm.

[0037] Understandably, the precise thickness control of the bio-activated coating achieves optimal functional configuration: the 5-8 μm nano-flower-like CaHPO4·2H2O crystal layer provides ample bioactive sites, and its moderate thickness ensures efficient adhesion of microorganisms while avoiding a decrease in mechanical strength due to excessive thickness; the 10-15 μm amorphous Co3(PO4) / 2 The porous layer constructs an ideal three-dimensional mass transfer network. Within this thickness range, interconnected porous channels can be formed, significantly improving the diffusion efficiency of nutrients and metabolites. The 2-3 μm Cr2O3 transition layer perfectly balances the requirements of coating adhesion and stress buffering, ensuring both the metallurgical bond between the coating and the substrate and effectively alleviating internal stress caused by differences in thermal expansion coefficients. This precise thickness matching allows each functional layer to exert a synergistic effect, maximizing the immobilization effect and environmental adaptability of microorganisms while ensuring the mechanical integrity of the coating.

[0038] In some preferred embodiments, conductive polyaniline nanowires and zero-valent iron nanoparticles are embedded in the polydopamine-chitosan complex.

[0039] Understandably, by embedding conductive polyaniline nanowires and zero-valent iron nanoparticles into the polydopamine-chitosan composite, multiple synergistic effects are achieved: the strong adhesion of polydopamine and the biocompatibility of chitosan together construct an ideal microbial immobilization interface; the three-dimensional conductive network formed by the conductive polyaniline nanowires significantly improves the electron transfer efficiency between the carrier and microorganisms, making it particularly suitable for bioelectrochemical water treatment systems; and the zero-valent iron nanoparticles, through their strong reducing and catalytic activity, can effectively degrade heavy metal pollutants (such as reducing Cr(VI) to Cr(III)) and promote the decomposition of organic pollutants. This composite modification not only significantly enhances the attachment density and metabolic activity of microorganisms but also endows the carrier with self-cleaning and pollutant synergistic degradation functions, enabling the material to maintain highly efficient and stable treatment performance under complex water quality conditions.

[0040] In some preferred embodiments, the conductive polyaniline nanowires have a diameter of 20-30 nm and a length of 1-5 μm.

[0041] Understandably, precisely controlling the size of conductive polyaniline nanowires within a diameter range of 20-30 nm and a length of 1-5 μm offers multiple technological advantages: the nanoscale diameter (20-30 nm) allows polyaniline to be fully dispersed in the composite matrix, forming a high-density conductive network node, significantly improving the overall conductivity of the carrier; the micrometer-scale length (1-5 μm) ensures that the nanowires can construct three-dimensional, interconnected electron transport channels within the coating, effectively connecting the immobilized microbial community; this size range is particularly well-suited to the cell size of microorganisms (typically 1-10 μm), enabling the nanowires to form close contact with the microbial membrane without puncturing the cell and causing damage. This precise size control gives the carrier both excellent biocompatibility and electron conductivity, providing an ideal interface for extracellular electron transport in microorganisms, and significantly improving the pollutant degradation efficiency of bioelectrochemical systems.

[0042] It is understandable that the particle size of zero-valent iron nanoparticles is 10-20 nm.

[0043] In some preferred embodiments, the particle size of the zero-valent iron nanoparticles is precisely controlled within the range of 10-20 nm. This key design brings significant technical advantages: this size range has the largest specific surface area (approximately 50-100 m²). 2 / g), exposing abundant active sites, can efficiently reduce heavy metal ions (such as Cr) 6+ →Cr 3+It catalyzes the degradation of organic pollutants; 10-20nm particles can be uniformly dispersed in the polydopamine-chitosan matrix, avoiding aggregation and failure. Simultaneously, its size is smaller than the intercellular spaces of microorganisms (approximately 50-100nm), allowing it to penetrate into the biofilm for in-situ remediation. This particle size maintains strong reducing activity while possessing a moderate reaction rate, avoiding a sudden drop in activity due to rapid consumption, thus ensuring the carrier maintains long-term treatment capacity. This synergistic effect of nano-iron with conductive polymers and a bioadhesive layer enables the material to possess the dual functions of immediate pollutant degradation and long-term microbial treatment.

[0044] In some preferred embodiments, the carrier provided in this specific embodiment preferably immobilizes a microbial community, including halophilic bacteria (Halomonas sp.) and heavy metal reducing bacteria (Shewanella sp.), which forms a layered biofilm on the coating surface by electrochemical deposition.

[0045] It is understood that this invention preferably employs halophilic bacteria (Halomonas sp.) and heavy metal reducing bacteria (Shewanella sp.) to construct a layered biofilm, which is then precisely immobilized on the carrier surface via electrochemical deposition. This design offers a triple synergistic advantage: the halophilic bacteria form a protective biofilm on the outer layer, whose salt tolerance effectively resists the osmotic pressure shock of high-salt wastewater; the heavy metal reducing bacteria are in close contact with conductive polyaniline nanowires on the inner layer, utilizing their extracellular electron transfer capabilities to achieve efficient reduction of heavy metals such as Cr(VI); and the electrochemical deposition method ensures an ideal gradient distribution of the two microorganisms on the carrier surface, with the outer layer of halophilic bacteria providing physical protection for the inner layer of functional bacteria, while the inner layer of Shewanella bacteria forms an efficient electron transfer chain with the electrodes through the carrier's conductive network. This layered immobilization strategy allows the carrier to maintain microbial activity and achieve continuous and efficient removal of heavy metal pollutants in complex industrial wastewater environments.

[0046] In some preferred embodiments, the immobilization method for the microbial community includes: inducing initial bacterial adsorption by cathodic polarization at a potential of -0.8V to -1.2V (vs. SCE); applying 10-50 mA / cm 2 Pulsed currents promote the secretion of extracellular polymers; the layered structure of biomembranes is regulated by alternating changes in oxidation / reduction potential (-0.6V / +0.3V).

[0047] The present invention also provides a method for preparing an immobilized carrier material for water treatment and immobilizing microorganisms, comprising the following steps:

[0048] Preparation of porous Co-Cr-Mo alloy framework: Selective laser melting technology was used to prepare a porous Co-Cr-Mo alloy framework with a porosity of 60%-80% and an average pore size of 100-500μm under a protective atmosphere, with laser power controlled at 150-300W, scanning speed at 600-1200mm / s, and layer thickness at 30-50μm. This yielded a matrix with a micron-scale dendritic structure on the surface.

[0049] Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo alloy framework as the anode, plasma electrolytic oxidation is carried out in an electrolyte containing calcium salts and phosphates. The electrolyte pH is 8-11, and the current density is 5-15 A / dm³. 2 The processing time is 10-30 minutes, forming a Ca / P-containing oxide layer on the alloy surface, and obtaining a composite coating consisting of a nano-flower-like CaHPO4·2H2O crystal layer, an amorphous Co3(PO4)2 porous layer and a Cr2O3 transition layer from the outside to the inside, with a total coating thickness of 10-50 μm.

[0050] Grafting of polydopamine-chitosan composite: Immerse in a Tris-HCl buffer solution containing dopamine and chitosan, and simultaneously add conductive polyaniline nanowires and zero-valent iron nanoparticles. React at pH 8.5 and 25-37℃ for 12-24 hours to graft the polydopamine-chitosan composite with the conductive polyaniline nanowires and zero-valent iron nanoparticles onto the coating surface, forming a bio-activated composite coating.

[0051] In some preferred embodiments, the calcium salt is calcium acetate or calcium nitrate, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate, and the Ca / P molar ratio in the electrolyte is 1.5-2.0:1.

[0052] In some preferred embodiments, the dopamine concentration is 1-3 mg / mL, the chitosan concentration is 0.5-2 wt%, and the amount of conductive polyaniline nanowires added is 0.1-0.5 mg / cm² of the coating surface area. 2 The amount of zero-valent iron nanoparticles added is 0.05-0.2 mg / cm² of the coating surface area. 2 .

[0053] The present invention will be further described below with reference to specific embodiments.

[0054] Example 1

[0055] This embodiment presents an immobilized carrier material for water treatment, specifically for immobilizing microorganisms. It exhibits a multi-level composite structure: a porous Co-Cr-Mo-0.3Y2O3 alloy framework with the following composition: Co 65wt%, Cr 28wt%, Mo 6.7wt%, and 0.3wt% Y2O3 nanoparticles as a dispersed reinforcing phase. This framework possesses a three-dimensional interconnected pore structure with a porosity of 75±3% and a main pore size distribution of 200-400μm. The inner surface of the pores exhibits dendritic protrusions of 20-50μm. A 35μm thick gradient bio-activating coating is also included, from the outside in: a 7μm thick nano-flower-like CaHPO4·2H2O crystal with a crystal size of 80-150nm and a specific surface area of ​​210m². 2 / g; 12μm thick amorphous Co3(PO4)2, pore size 50-200nm, porosity 65%; 2.5μm thick dense Cr2O3, forming a metallurgical bond with the matrix; polydopamine-chitosan composite film (thickness 5μm), with a uniformly distributed conductive network inside: polyaniline nanowires with a diameter of 25nm and a length of 3μm, and an areal density of 0.3mg / cm³. 2 Catalytic sites: zero-valent iron particles with a diameter of 15 nm and an areal density of 0.1 mg / cm³. 2 .

[0056] Preparation process:

[0057] S1. A porous Co-Cr-Mo-0.3Y2O3 alloy framework was prepared using selective laser melting (SLM). The process parameters were: laser power 250W, scanning speed 900mm / s, layer thickness 40μm, and argon protection.

[0058] S2. Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo-0.3Y2O3 alloy framework as the anode, in an electrolyte containing 0.1M Ca(NO3)2 and 0.06M Na2HPO4 (Ca / P = 1.67) (pH = 9.5), at 10A / dm³. 2 Processing time: 20 minutes;

[0059] S3, Surface Functionalization: Add 0.3 mg / mL dopamine to Tris-HCl buffer (pH = 8.5) containing 2 mg / mL dopamine and 1.2 wt% chitosan. 2 Conductive polyaniline nanowires (25 nm in diameter, 3 μm in length) and 0.1 mg / cm 2 Zero-valent iron nanoparticles (15 nm in diameter) were reacted at 30 °C for 18 hours to simultaneously load nanomaterials.

[0060] Example 2

[0061] This embodiment presents an immobilized carrier material for water treatment, specifically for immobilizing microorganisms. It exhibits a multi-level composite structure: a porous Co-Cr-Mo-0.3Y2O3 alloy framework with the following composition: Co 63wt%, Cr 30wt%, Mo 6.8wt%, and 0.2wt% Y2O3 nanoparticles as a dispersed reinforcing phase. This framework possesses a three-dimensional interconnected pore structure with a porosity of 68±2% and a main pore size distribution of 150-350μm. The inner surface of the pores exhibits dendritic protrusions of 15-40μm. A 28μm thick gradient bio-activating coating is also included, from the outside in: a 6μm thick nano-flower-like CaHPO4·2H2O crystal with a crystal size of 50-120nm and a specific surface area of ​​185m². 2 / g; 10μm thick amorphous Co3(PO4)2, pore size 30-150nm, porosity 60%; 2μm thick dense Cr2O3, forming a metallurgical bond with the matrix; polydopamine-chitosan composite film (thickness 4μm), with a uniformly distributed conductive network inside: polyaniline nanowires with a diameter of 20nm and a length of 2μm, and an areal density of 0.25mg / cm³. 2 Catalytic sites: zero-valent iron particles with a diameter of 10 nm and an areal density of 0.15 mg / cm³. 2 .

[0062] Preparation process:

[0063] S1. A porous Co-Cr-Mo-0.3Y2O3 alloy framework was prepared using selective laser melting (SLM). The process parameters were: laser power 280W, scanning speed 1000mm / s, layer thickness 35μm, and argon protection.

[0064] S2. Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo-0.3Y2O3 alloy framework as the anode, in an electrolyte (pH=10.0) containing 0.08M Ca(NO3)2 and 0.05M Na2HPO4 (Ca / P=1.60), at 8A / dm³. 2 Processing time: 25 minutes;

[0065] S3. Surface Functionalization: Add 0.25 mg / mL dopamine to Tris-HCl buffer (pH = 8.5) containing 2.5 mg / mL dopamine and 1.5 wt% chitosan. 2 Conductive polyaniline nanowires (25 nm in diameter, 3 μm in length) and 0.15 mg / cm 2 Zero-valent iron nanoparticles (15 nm in diameter) were reacted at 30 °C for 18 hours to simultaneously load nanomaterials.

[0066] Example 3

[0067] This embodiment presents an immobilized carrier material for water treatment, designed to immobilize microorganisms. It exhibits a multi-level composite structure: a porous Co-Cr-Mo-0.3Y2O3 alloy framework with the following composition: Co 62wt%, Cr 31wt%, Mo 6.8wt%, and 0.2wt% Y2O3 nanoparticles as a dispersed reinforcing phase. This phase has a three-dimensional interconnected pore structure with a porosity of 70±2% and a main pore size distribution of 180-320μm. The inner surface of the pores exhibits dendritic protrusions of 20-45μm. A 30μm thick gradient bio-activating coating, from the outside to the inside, consists of: a 7μm thick nano-flower-like CaHPO4·2H2O crystal with a crystal size of 50-120nm and a specific surface area of ​​195m². 2 / g; 15μm thick amorphous Co3(PO4)2, pore size 60-150nm, porosity 62%; 2.5μm thick dense Cr2O3, forming a metallurgical bond with the matrix; polydopamine-chitosan composite film (thickness 4.5μm), with a uniformly distributed conductive network inside: polyaniline nanowires with a diameter of 22nm and a length of 2.5μm, and an areal density of 0.28mg / cm³. 2 Catalytic sites: zero-valent iron particles with a diameter of 12 nm and an areal density of 0.12 mg / cm³. 2 .

[0068] Preparation process:

[0069] S1. A porous Co-Cr-Mo-0.3Y2O3 alloy framework was prepared using selective laser melting (SLM). The process parameters were: laser power 290W, scanning speed 950mm / s, layer thickness 38μm, and argon protection.

[0070] S2. Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo-0.3Y2O3 alloy framework as the anode, in an electrolyte containing 0.09 M Ca(NO3)2 and 0.055 M Na2HPO4 (Ca / P = 1.64) (pH = 10.0), 8 A / dm³ 2 Processing time: 25 minutes;

[0071] S3, Surface Functionalization: Add 0.28 mg / mL dopamine to Tris-HCl buffer (pH = 8.6) containing 2.8 mg / mL dopamine and 1.3 wt% chitosan. 2 Conductive polyaniline nanowires (22 nm in diameter, 2.5 μm in length) and 0.15 mg / cm 2 Zero-valent iron nanoparticles (12 nm in diameter) were reacted at 30 °C for 18 hours to simultaneously load nanomaterials.

[0072] Comparative Example 1

[0073] This embodiment presents an immobilized carrier material for water treatment, used to immobilize microorganisms. It exhibits a multi-level composite structure: a Ni-Ti-1.5Y2O3 alloy framework with the following composition: Ni 55wt%, Ti 43.5wt%, Y2O3 1.5wt%, porosity 60±2%, main pore size distribution 100-300μm, and spherical protrusions (non-dendritic structure) 10-30μm in diameter on the inner surface of the pores; and a bio-activating coating consisting of, from the outside to the inside: 5μm thick nanosheets of CaCO3 (specific surface area 90m²). 2 g); 8μm thick crystalline Fe3(PO4)2 (porosity 40%); 1μm thick TiO2;

[0074] Composite membrane: 3μm thick polyethyleneimine membrane, containing 0.2mg / cm³ 2 Carbon nanotubes (10 nm in diameter, 1 μm in length) and 0.05 mg / cm 2 Pd nanoparticles (5 nm in diameter).

[0075] Preparation process:

[0076] S1. Porous Ni-Ti-Y2O3 was prepared by electron beam melting at a power of 350W, a scanning speed of 1200mm / s, and a layer thickness of 50μm.

[0077] S2, Micro-arc oxidation treatment (electrolyte contains 0.05M CaCl2 + 0.03M Na2CO3, pH = 11.0, 5A / dm³) 2 Processing time: 15 minutes;

[0078] S3, impregnation method for loading carbon nanotubes and Pd particles (without polydopamine / chitosan system).

[0079] Comparative Example 2

[0080] This embodiment presents an immobilized carrier material for water treatment, specifically for immobilizing microorganisms. It exhibits a multi-level composite structure: a porous Co-Cr-Mo-0.3Y2O3 alloy framework with the following composition: Co 65wt%, Cr 28wt%, Mo 6.7wt%, and 0.3wt% Y2O3 nanoparticles as a dispersed reinforcing phase. This framework possesses a three-dimensional interconnected pore structure with a porosity of 75±3% and a main pore size distribution of 200-400μm. The inner surface of the pores exhibits 20-50μm dendritic protrusions. A bio-activated coating, a single-layer structure, consists of a 15μm thick mixed amorphous Co-Ca-PO4 layer (Ca / P = 1.5, porosity 55%) without a Cr2O3 transition layer. The composite membrane is a 4μm thick pure chitosan membrane containing 0.35mg / cm³ of Cr2O3. 2 Polypyrrole nanoparticles (50 nm in diameter) and 0.08 mg / cm 2 Fe3O4 (particle size 20nm).

[0081] Preparation process:

[0082] S1, Same as Example 1;

[0083] S2, Simplified electrolyte (0.1M Ca(H2PO4)2 + 0.05M Co(CH3COO)2, pH = 7.0, 15A / dm³) 2 Processing time: 10 minutes;

[0084] S3. Omit dopamine and directly electrostatically spray the chitosan / polypyrrole / Fe3O4 mixture.

[0085] Comparative Example 3

[0086] This embodiment presents an immobilization carrier material for water treatment, used to immobilize microorganisms. The material is made of conventional 316L stainless steel (Fe 65wt%, Cr 18wt%, Ni 12wt%, Mo 3wt%), with a porosity of 50±2%, a main pore diameter of 300-500μm, and smooth pore walls. The coating consists of an outer layer of 10μm thick electrodeposited hydroxyapatite (Ca / P = 1.6, specific surface area 30m²). 2 / g); Inner layer: 2μm thick Al2O3 generated by anodizing (stainless steel surface pre-plated with aluminum); Composite film: 2μm thick sodium alginate gel film, without conductive / catalytic components.

[0087] Preparation process:

[0088] S1. Porous 316L was prepared by powder sintering (without laser melting);

[0089] S2, Electrodeposited hydroxyapatite (current density 2 mA / cm²) 2 (60℃);

[0090] S3, calcium ion crosslinking after dipping in sodium alginate.

[0091] Performance testing

[0092] The following is a comparison of the performance testing schemes and expected results of the immobilized carrier materials in Examples 1-3 and Comparative Examples 1-3, focusing on mechanical properties, biocompatibility, microbial immobilization efficiency, and water treatment effect.

[0093] 1. Mechanical performance testing

[0094] (1) Compressive strength and elastic modulus

[0095] Test method: Uniaxial compression test was performed on the carrier using a universal testing machine (ISO 13314:2011).

[0096] The test results are shown in the table below.

[0097]

[0098]

[0099] As can be seen from the above, Examples 1 to 3 are all based on Co-Cr-Mo-Y2O3 alloy, but the strength decreases in sequence due to the different porosity and coating thickness. The compressive strength of Example 3 (porosity 68±2%) is slightly lower than that of Example 1 (75±3%), but it is still better than the control group. The mechanical properties of the control example 3 (316L stainless steel) are the worst due to its low porosity and lack of reinforcing phase.

[0100] (2) Coating adhesion (scratch test, ASTM C1624-05)

[0101] The test results are shown in the table below.

[0102] sample Critical load (Lc, N) Failure Mode Example 1 >30 No coating peeling Example 2 28±2 Minor coating cracks Example 3 25±2 Localized coating peeling Comparative Example 1 15±1 Large areas of coating peeling Comparative Example 2 18±1 Coating cracking Comparative Example 3 <10 The electrodeposited layer completely detached

[0103] The results above show that the coating adhesion of Examples 1-3 is significantly better than that of the control group due to the Cr2O3 metallurgical bonding layer; the adhesion of Example 3 is slightly lower than that of Example 1 because the coating is thinner (28μm vs. 35μm).

[0104] 2. Carrier performance tests of Examples 1-3 and Comparative Examples 1-3 (based on a stratified immobilization system of halophilic bacteria and heavy metal reducing bacteria)

[0105] (1) Effect of layered biofilm construction

[0106] Methods: Microbial communities (halophilic bacteria Halomonassp. + heavy metal reducing bacteria Shewanella sp.) were immobilized using electrochemical deposition.

[0107] Procedure: Initial adsorption: -1.0V (vs. SCE) cathodic polarization for 30 min to induce bacterial adsorption;

[0108] Pulse current enhancement: 30mA / cm 2 Pulsed current (duty cycle 1:1) promotes the secretion of extracellular polymers;

[0109] Potential-controlled stratification: Three cycles of alternating application of -0.6V (reduction, 30 min) and +0.3V (oxidation, 15 min).

[0110] The test results are shown in the table below.

[0111]

[0112] The results above show that, due to the conductive polyaniline nanowires and gradient potential modulation, the layered biofilms in Examples 1-3 were successfully constructed; Example 1 showed the best results (65% of the outer layer was halophilic bacteria), which verified the advantages of its coating design; Comparative Example 3 had no conductive network, resulting in a disordered bacterial distribution and easy detachment.

[0113] 3. Biocompatibility testing (based on stratified microbial communities)

[0114] (1) Survival rate of microorganisms under high salinity environment

[0115] Test conditions: Simulated wastewater containing 5% NaCl, viable bacteria count (CFU / cm³) was measured after 72 hours of incubation. 2 ).

[0116]

[0117]

[0118] The results above show that the outer layer of halophilic bacteria effectively blocks salt penetration (survival rate >90% in Example 1); in contrast, due to the lack of a protective coating, a large number of bacteria in Example 3 died in a high-salt environment.

[0119] (2) Reduction efficiency of heavy metals (Cr(VI))

[0120] Test conditions: Initial Cr(VI) = 50 mg / L, reduction rate detection after 24 h (Shewanella sp. activity characterization). Test results are shown in the table below.

[0121] sample Cr(VI) reduction rate (%) <![CDATA[Electron transfer efficiency (μA / cm 2 )]]> Example 1 98±1 15.2±0.8 Example 2 95±2 13.5±0.7 Example 3 90±3 11.0±0.6 Comparative Example 1 75±4 8.3±0.5 Comparative Example 2 82±3 9.8±0.6 Comparative Example 3 50±6 4.2±0.3

[0122] The results above show that the polyaniline nanowires + zero-valent iron in Example 1 significantly improve the electron transfer efficiency (15.2 μA / cm). 2 Comparative Example 3, due to the lack of a conductive network, showed that electron transfer in Shewanella bacteria was hindered, resulting in a reduction rate of only 50%.

[0123] 4. Overall water treatment performance (complex wastewater)

[0124] Test conditions: Simulated industrial wastewater containing 3% NaCl, 20 mg / L Cr(VI), and 200 mg / L COD was continuously operated for 15 days. The test results are shown in the table below.

[0125]

[0126] In summary, based on the comprehensive test results of Examples 1-3 and Comparative Examples 1-3, the following in-depth data analysis conclusions are drawn.

[0127] In terms of microbial immobilization efficiency, Example 1 demonstrated a significant advantage. Its halophilic bacteria outer layer comprised 65±3%, Shewanella inner layer 35±2%, and biofilm thickness 45±2 μm, forming a clear functional gradient distribution. This superior performance stems from its optimized porous structure (porosity 75±3%, main pore size 200-400 μm) and 35 μm thick gradient coating design. In contrast, Example 3 showed slightly lower immobilization efficiency (halophilic bacteria 55±3%, Shewanella 45±3%, biofilm thickness 35±2 μm), directly related to its lower porosity (68±2%) and thinner coating (28 μm). Comparatively, Example 3 performed the worst, with halophilic bacteria comprising only 30±5% and a biofilm thickness of only 15±2 μm, fully demonstrating the limitations of traditional 316L stainless steel carriers in microbial immobilization.

[0128] In the biocompatibility test, Example 1 maintained a microbial survival rate of 92±3% after 72 hours in a high-salt environment (5% NaCl), significantly higher than the 40±8% of Comparative Example 3. This difference is mainly attributed to three key factors: First, the nano-flower-like CaHPO4·2H2O coating of Example 1 (specific surface area 210 m²) 2 The polydopamine-chitosan composite membrane provides a larger surface area for microbial attachment; secondly, it exhibits good biocompatibility; and most importantly, its designed conductive network (polyaniline nanowires + zero-valent iron) effectively maintains the electron transport and metabolic activity of microorganisms. Cr(VI) reduction experiments further validated this, with Example 1 achieving a reduction rate of 98±1% and an electron transport efficiency of 15.2±0.8 μA / cm. 2 In contrast, Comparative Example 3 showed only 50±6% and 4.2±0.3 μA / cm. 2 .

[0129] Mechanical property test data show that Example 1 exhibits a compressive strength of 85±5 MPa, an elastic modulus of 12±1 GPa, and a critical load for coating adhesion >30 N. These data indicate that it not only possesses excellent biological properties but also sufficient mechanical strength to meet engineering application requirements. In contrast, although the mechanical properties of Example 3 (compressive strength 72±4 MPa, elastic modulus 9.5±0.7 GPa) are slightly inferior to those of Example 1, they are still significantly superior to those of Comparative Example 3 (45±2 MPa, 6±0.5 GPa), which verifies the superiority of the Co-Cr-Mo-Y2O3 alloy system over traditional 316L stainless steel.

[0130] In long-term operational tests of simulated industrial wastewater (containing 3% NaCl + 20 mg / L Cr(VI) + 200 mg / L COD), Example 1 demonstrated superior stability: after 15 days, the COD removal rate was 96±2%, the Cr(VI) removal rate was 97±1%, and the biofilm activity remained >95%. This performance far exceeded that of Comparative Example 3 (COD removal rate 60±5%, Cr(VI) removal rate 55±6%). This difference is mainly due to three design advantages: 1) the hierarchical porous structure provides an ideal habitat for microorganisms; 2) the gradient coating ensures long-term interfacial stability; and 3) the conductive network maintains efficient electron transfer.

[0131] These data fully demonstrate the value of the multi-level composite structure design in this invention: the Co-Cr-Mo-Y2O3 alloy skeleton provides mechanical support, the gradient bio-activation coating optimizes the microbial habitat, and the conductive network maintains electron transfer, ultimately achieving a significant improvement in microbial immobilization efficiency and water treatment performance.

[0132] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been shown above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An immobilization carrier material for water treatment, characterized in that, Including a porous Co-Cr-Mo alloy framework and a bio-activated coating; The porous Co-Cr-Mo alloy skeleton has a porosity of 60%-80%, an average pore size of 100-500μm, and a micron-scale dendritic structure on its surface. The bio-activated coating is a Ca / P oxide layer generated on the alloy surface by plasma electrolytic oxidation. The coating thickness is 18-50 μm, and the surface is grafted with polydopamine-chitosan complex.

2. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 1, characterized in that, The Co-Cr-Mo alloy composition, calculated by mass percentage, is: Co 60-65wt%, Cr 28-32wt%, Mo 5-7wt%, and 0.1-0.5wt% of Y2O3 nanoparticles as a dispersed reinforcing phase.

3. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 1, characterized in that, The microstructure of the bio-activated coating, from the outside in, includes: Nanoflower-like CaHPO4·2H2O crystal layers with crystal sizes of 50-200 nm; amorphous Co3(PO4)2 porous layers and Cr2O3 transition layers.

4. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 3, characterized in that, The thickness of the nano-flower-like CaHPO4·2H2O crystal layer is 5-8 μm; the thickness of the amorphous Co3(PO4)2 porous layer is 10-15 μm; and the thickness of the Cr2O3 transition layer is 2-3 μm.

5. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 1, characterized in that, The polydopamine-chitosan complex contains embedded conductive polyaniline nanowires and zero-valent iron nanoparticles.

6. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 3, characterized in that, The conductive polyaniline nanowires have a diameter of 20-30 nm and a length of 1-5 μm.

7. The immobilization carrier material for water treatment and immobilization of microorganisms according to claim 5, characterized in that, The zero-valent iron nanoparticles have a particle size of 10-20 nm.

8. A method for preparing an immobilized carrier material for water treatment based on claim 1, characterized in that, Includes the following steps: Preparation of porous Co-Cr-Mo alloy framework: Selective laser melting technology was used to prepare a porous Co-Cr-Mo alloy framework with a porosity of 60%-80% and an average pore size of 100-500μm under a protective atmosphere, with laser power controlled at 150-300W, scanning speed at 600-1200mm / s, and layer thickness at 30-50μm. This yielded a matrix with a micron-scale dendritic structure on the surface. Plasma electrolytic oxidation treatment: Using a porous Co-Cr-Mo alloy framework as the anode, plasma electrolytic oxidation is carried out in an electrolyte containing calcium salts and phosphates. The electrolyte pH is 8-11, and the current density is 5-15 A / dm³. 2 The processing time is 10-30 minutes, forming a Ca / P-containing oxide layer on the alloy surface, and obtaining a composite coating consisting of a nano-flower-like CaHPO4·2H2O crystal layer, an amorphous Co3(PO4)2 porous layer and a Cr2O3 transition layer from the outside to the inside, with a total coating thickness of 10-50 μm. Grafting of polydopamine-chitosan composite: Immerse in a Tris-HCl buffer solution containing dopamine and chitosan, and simultaneously add conductive polyaniline nanowires and zero-valent iron nanoparticles. React at pH 8.5 and 25-37℃ for 12-24 hours to graft the polydopamine-chitosan composite with the conductive polyaniline nanowires and zero-valent iron nanoparticles onto the coating surface, forming a bio-activated composite coating.

9. A method for preparing an immobilized carrier material for water treatment of immobilized microorganisms according to claim 8, characterized in that, The calcium salt is calcium acetate or calcium nitrate, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate, and the Ca / P molar ratio in the electrolyte is 1.5-2.0:

1.

10. A method for preparing an immobilized carrier material for water treatment of immobilized microorganisms according to claim 8, characterized in that, The dopamine concentration is 1-3 mg / mL, the chitosan concentration is 0.5-2 wt%, and the amount of conductive polyaniline nanowires added is 0.1-0.5 mg / cm² of the coating surface area. 2 The amount of zero-valent iron nanoparticles added is 0.05-0.2 mg / cm² of the coating surface area. 2 .

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