Waterweed-imitated rope-shaped iron-lanthanum modified bamboo-based biofilm filler and preparation method thereof

Abstract

The application discloses a water-weed-imitated rope-shaped iron-lanthanum modified bamboo-based biomembrane filler and a preparation method thereof. The filler is composed of a core rope and an outer coating layer. The core rope is a twisted bamboo-based wire rope, and the outer coating layer is a loose bamboo-based wire bundle. The whole is subjected to high-temperature carbonization for pore formation under a protective atmosphere or a vacuum condition, and is loaded with an adsorption active layer containing one or more than one of iron and lanthanum. The filler is provided with a fixed mounting structure and is used for being hung and mounted in a water treatment device.

Description

Technical Field

[0001] This invention belongs to the field of water ecological restoration technology, specifically relating to a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants and its preparation method. Background Technology

[0002] (a) Pollution problem of plastic fillers

[0003] Existing decentralized wastewater treatment systems generally use suspended or elastic packing materials made of petroleum-based plastics such as polyethylene (PE) and polypropylene (PP). These packing materials have the following drawbacks: (1) they are derived from non-renewable petroleum resources, which does not conform to the national strategy of "replacing plastic with bamboo"; (2) they are non-degradable and will cause secondary pollution from plastic waste after their service life expires; (3) the production process is energy-intensive and has high carbon emissions; and (4) they cannot be recycled and reused after being discarded.

[0004] (ii) Limitations of existing aquatic plant / bio-rope fillers

[0005] Existing aquatic plant-like fillers (such as biomimetic aquatic plant filler for water purification CN200520015584.6, Hebei Yisheng Environmental Protection aquatic plant-like / braided / upright aquatic plant filler, Shijiazhuang Songyu Environmental Protection aquatic plant-like braided filler, Jiangsu Boxing aquatic plant-like biological filler, etc.) are all made of woven chemical fibers or plastic filaments or soft plastic sheets, resulting in white pollution and microplastic problems. Existing biological rope fillers (such as Jiangsu Jixiang Environmental Protection CN208500488U, Yixing Suez Environment CN211283860U, Shanghai Tianweiya CN107098479A, etc.) use a plastic filament woven core + wire mesh / ring mesh structure, with limited functionality and no phosphorus adsorption capacity. Existing aquatic plant-like rope fillers (the mainstream market specification with an outer diameter of 40-100mm), although structurally rope-like, are all made of plastic or chemical fibers, lacking bamboo-based materials, high-temperature carbonization, and metal oxide modification, thus failing to achieve simultaneous chemical phosphorus removal.

[0006] (III) Limitations of existing bamboo fiber fillers

[0007] Existing bamboo fiber fillers (such as coarse bamboo fiber wastewater treatment filler CN103145236B, Liu Tianchi et al., 2014) are only mechanically processed and alkali-treated, without high-temperature carbonization. They are coarse, low-strength, and easily perishable, lacking chemical modification and phosphorus removal capabilities. Furthermore, existing bamboo fiber fillers do not form a core-external composite loose structure resembling aquatic plant ropes, making them unsuitable for direct suspension in purification tanks. In addition, existing bamboo fiber aquatic plant-like fillers require multiple processes such as kneading, fiber separation, and high-temperature carbonization, resulting in significant equipment investment and substantial fiber strength loss. Traditional bamboo strip weaving technology is mature, low-cost, and utilizes the natural toughness of bamboo, but its smooth surface results in low biofilm formation and lacks a core-external composite loose structure resembling aquatic plant ropes. It is also not combined with iron-lanthanum modification technology and lacks chemical phosphorus removal capabilities. Therefore, developing a technology that directly uses bamboo strips in aquatic plant-like rope fillers, retaining the strength advantages of bamboo strips while addressing biofilm formation and phosphorus removal through a loose fiber bundle structure, is a crucial technological approach in this field.

[0008] (iv) The gap in environmental protection equipment that uses bamboo instead of plastic

[0009] Under the "replacing plastic with bamboo" strategy, existing patents are mostly concentrated on packaging materials, while the patent layout for replacing plastic with bamboo in the field of environmental water treatment equipment is relatively blank.

[0010] Therefore, there is an urgent need for a bamboo-based biofilm filler that mimics aquatic plants and combines biological decontamination with chemical phosphorus removal functions, as well as its preparation and application methods. Summary of the Invention

[0011] The purpose of this invention is to provide a bamboo-based biofilm filler with iron-lanthanum modified rope-like structure that mimics aquatic plants and its preparation method, in order to solve the problems of existing plastic fillers being non-degradable, having limited functions, having low strength and being prone to decay of natural bamboo fibers, and the fact that bamboo strips have not been used in mimicking aquatic plants.

[0012] The present invention provides a bamboo-based biofilm filler with iron-lanthanum modified in the form of aquatic plant rope, comprising a core rope, an outer coating layer, a fixing and installation structure, and an adsorption active layer.

[0013] The core rope is a rope-shaped core formed by twisting together multiple carbonized bamboo baseline materials;

[0014] The outer covering layer is a fluffy layer composed of several carbonized bamboo base material bundles. The outer covering layer surrounds the core rope. The carbonized bamboo base material bundles are distributed at intervals along the length of the filler. At least one end or middle of a portion of the carbonized bamboo base material bundles is fixed to the core rope, and the other portion extends radially or obliquely to the core rope to form a free fluffy part. The radial extension length of the free fluffy part is not less than the radius of the core rope. A gap is formed between the outer covering layer and the core rope for water flow and biofilm attachment.

[0015] The adsorption active layer is attached to at least one location on the surface and in the pores of the core rope and the outer coating layer, and the adsorption active layer contains iron oxide and lanthanum oxide;

[0016] The fixed installation structure is located at the end of the packing material and consists of a connector that is fixedly connected to the end of the core rope or the outer covering layer. It is used to suspend the packing material on the support of the water treatment device.

[0017] Preferably, the carbonized bamboo base material is formed by carbonizing bamboo raw fiber twisted thread, bamboo strips, or a combination of both; the diameter of the bamboo raw fiber twisted thread before carbonization is 0.1mm-1.5mm; the bamboo strips are bamboo green strips after removing the bamboo yellow, with a width of 1mm-20mm and a thickness of 0.1mm-3mm before carbonization.

[0018] Preferably, the molar ratio of iron to lanthanum in the adsorption active layer is 0.5:1-4:1, and the loading of the adsorption active layer relative to the dry weight of the filler is 2wt%-35wt%.

[0019] Preferably, the diameter of the core rope is 3mm-40mm, the total diameter of the filler is 20mm-150mm, and the diameter of the core rope (1) is not greater than half of the total diameter of the filler.

[0020] Preferably, the free fluff portion extends 5mm-80mm beyond the outer surface of the core rope, and the spacing between adjacent free fluff portions along the length direction of the filler is 5mm-100mm.

[0021] Preferably, the core rope is a twisted rope made of carbonized bamboo strips, a twisted rope made of carbonized bamboo fibers, or a combination thereof, and the outer covering layer is a loose layer of carbonized bamboo fiber bundles, a loose layer of carbonized bamboo strip bundles, or a combination thereof, forming a core-and-fiber outer structure, a core-and-fiber outer structure, or a mixed weaving structure.

[0022] Preferably, the outer covering layer 9 of the thin bamboo strips is fixed to the outer periphery of the core rope by one or more of the following methods: spiral winding, segmented binding, annular winding, or clamping fixation.

[0023] Preferably, the fixing and installation structure is one or more of the following: stainless steel ring, bamboo fiber knot, plastic buckle, metal hook, or rope-like end binding structure.

[0024] Preferably, the effective suspension length of the packing is 500mm-8000mm.

[0025] Preferably, the filler is one of the following: a wound and dispersed structure, a loose and dispersed structure, a solid twisted structure, or a multi-strand twisted structure.

[0026] The present invention discloses a method for preparing a bamboo-based biofilm filler with iron-lanthanum modified in the form of aquatic plants, comprising the following steps:

[0027] (1) Raw material preparation: Bamboo fiber twisted yarn is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 0.1-1.5mm; bamboo strips are bamboo green strips after removing bamboo yellow, with a width of 1-20mm and a thickness of 0.1-3mm;

[0028] (2) Shaping: Twisted bamboo fibers and bamboo strips are made into the required shape to obtain the filler semi-finished product;

[0029] (3) Carbonization: The semi-finished packing is heated to 300-900℃ in a protective atmosphere or vacuum at a rate of 1℃ / min-10℃ / min and held for 0.5h-4h to obtain carbonized packing;

[0030] (4) Modification: The carbonized filler is immersed in a metal salt solution containing iron salt and lanthanum salt, and is immersed for 2-48 hours under normal pressure, negative pressure or ultrasonic-assisted impregnation. After immersion, it is dried at 60℃-120℃ for 1-3 hours and then calcined at 250℃-500℃ for 0.5-4 hours to obtain bamboo-based biofilm filler with adsorption active layer.

[0031] The above-mentioned method for preparing a waterweed-like rope-shaped iron-lanthanum modified bamboo-based biofilm filler includes a step (4) in which the core rope and outer covering layer are bamboo strips, and the soaking time is 4-48h.

[0032] The above-mentioned method for preparing a bamboo-based biofilm filler with imitation aquatic plant rope-like iron-lanthanum modified material, wherein the protective atmosphere in step (3) is: an inert gas including one or more of nitrogen, argon or helium; and the vacuum condition is a negative pressure environment with an internal furnace pressure of 800-1000 Pa.

[0033] The above-mentioned method for preparing a bamboo-based biofilm filler with iron-lanthanum modified rope-like imitation aquatic plant material, wherein the iron salt mentioned in step (4) is one or more of FeCl3, Fe(NO3)3 or FeSO4.

[0034] The above-mentioned method for preparing a bamboo-based biofilm filler with imitation aquatic plant rope-like iron-lanthanum modified material, wherein the lanthanum salt in step (4) is one or more of La(NO3)3, LaCl3 or La2(SO4)3.

[0035] Compared with the prior art, the present invention has the following beneficial effects, as can be seen from the above technical solution:

[0036] (1) Replacing plastic with bamboo: Replacing petroleum-based plastics with renewable bamboo base material is in line with the national strategy of "replacing plastic with bamboo" and the "dual carbon" goal, reducing plastic pollution and carbon emissions. The bamboo strips directly utilize the toughness of bamboo green, eliminating the fiberization process, resulting in lower cost and higher strength. The wire material is pyrolyzed at 300℃-900℃ under protective atmosphere or vacuum conditions, which decomposes the cellulose, hemicellulose and lignin in the bamboo material to form carbonized bamboo base material with a porous carbon skeleton structure, thereby significantly improving its dimensional stability and corrosion resistance under long-term immersion conditions.

[0037] (2) Biomimetic structure: The fluffy structure resembling aquatic plants has a significantly increased specific surface area and low water flow resistance, resulting in a fast microbial biofilm formation rate and a better biofilm formation effect than traditional petroleum-based plastic fillers, which is conducive to the attachment and growth of microorganisms.

[0038] (3) Core-outer composite reinforcement: The core rope provides tensile strength, and the outer coating provides space for film attachment. After carbonization, the overall rigidity is good and it can withstand water flow impact for 3-5 years without collapsing or short-circuiting, meeting the stringent requirements of "zero operating cost and maintenance-free" for rural purification tanks. The strength of bamboo strip core rope is significantly better than that of bamboo fiber core rope, and it is suitable for high load and deep water conditions. The differentiated density structure of the dense core layer and the loose outer layer further improves the durability and water flow impact resistance of the filler.

[0039] (4) Mixed weaving structure: The mixed weaving structure of core strip and outer fiber or core fiber and outer strip takes into account the high strength of bamboo strips and the high specific surface area of ​​bamboo fiber bundles, and has the best comprehensive performance.

[0040] (5) Iron-lanthanum modified synchronous phosphorus removal: The adsorption active layer endows the packing with chemical phosphorus removal ability. The iron-lanthanum composite oxide has a high affinity for phosphate, and the phosphorus adsorption capacity is significantly improved. It works in synergy with the biodegradation function of the biofilm to achieve synchronous nitrogen and phosphorus removal without the need for additional chemical phosphorus removal agents.

[0041] (6) Advantages of solid twist and multi-strand twist: Solid twist is simple to produce and does not require core rope or braiding machine. It can be produced by hand or simple twisting machine, which is suitable for small-scale decentralized scenarios. Multi-strand twist has high strength and good flexibility. The rope diameter can be flexibly controlled by adjusting the number of strands to adapt to different water depths and flow rates.

[0042] (7) Convenient suspension installation: The fixed installation structure includes a top suspension fixing end, a side clamping structure, a binding fixing structure, or direct fixing by rope-like end binding. The installation method is flexible, requires no bottom support, and requires zero maintenance. It is suitable for unattended operation in rural decentralized scenarios. The effective suspension length can reach 8000mm, covering the 8-meter water depth requirement of municipal sewage treatment plants.

[0043] (8) Carbon sink value-added: Bamboo fiber and bamboo strips are renewable biomass materials that absorb CO2 during the growth process. The structural features of the filler in this invention enable the bamboo-based carbon skeleton to exist stably in the water treatment device for a long time, forming a fixed carbon sink, which is conducive to carbon trading declaration. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of the aquatic plant-inspired rope-shaped iron-lanthanum modified bamboo-based biofilm filler (core-external composite type) of the present invention.

[0045] Figure 2 for Figure 1 Schematic diagram of the AA-direction cross section;

[0046] Figure 3 This is a schematic diagram of the invention in use when suspended and installed inside a purification tank;

[0047] Figure 4 This is a schematic diagram illustrating the phosphorus adsorption principle of the active adsorption layer in this invention.

[0048] Figure 5 This is a schematic diagram of the cross-section of the bamboo strips used in this invention;

[0049] Figure 6 This is a schematic cross-sectional view of the core-fiber and outer-fiber hybrid structure of the present invention;

[0050] Figure 7 This is a schematic diagram of the core fiber and outer bamboo strip hybrid weaving structure of the present invention;

[0051] Figure 8 This is a schematic diagram of the large-size packing structure of the present invention;

[0052] Figure 9 This is a schematic diagram of the outer coating layer fixing method of the present invention;

[0053] Figure 10 This is a schematic diagram of a entangled, scattering structure.

[0054] Figure 11 A supplementary structural diagram for a solid twisted structure;

[0055] Figure 12 A schematic diagram of a supplementary structure for a multi-strand twisted structure;

[0056] Figure 13 This is a schematic diagram of a fluffy, scattered structure.

[0057] In the diagram: 1-core rope, 2-outer covering layer, 3-fixed installation structure, 4-purification tank, 5-adsorption active layer, 6-bamboo strip, 7-bamboo fiber filler, 8-bamboo base material, 9-fine bamboo strip outer covering layer, 10-outer woven mesh, 14-central shaft core, 15-winding and spreading layer, 16-solid rope-like body, 17-multi-strand composite body, 18-porous carbon skeleton, 19-fluffy spreading layer. Detailed Implementation

[0058] The term "carbonization" as used in this specification refers to the pyrolysis treatment of bamboo baseline material 8 under a protective atmosphere or vacuum conditions at a temperature of 300℃ to 900℃, which causes the cellulose, hemicellulose, and lignin in the bamboo baseline material 8 to undergo pyrolysis, forming a porous carbon skeleton 18 structure dominated by a carbon skeleton. The carbonized bamboo baseline material 8 exhibits significantly better structural stability than the uncarbonized bamboo baseline material 8 under long-term immersion in water.

[0059] The carbonized bamboo baseline material 8 can be identified by the following methods: (1) X-ray diffraction analysis (XRD): The carbonized bamboo baseline material 8 shows broadened amorphous carbon characteristic peaks at approximately 23° and 43° of 2θ, while the protocellulose crystallization peaks disappear; (2) Raman spectroscopy: The carbonized material shows a broadened amorphous carbon characteristic peak at approximately 1350 cm⁻¹ of 2θ. -1 (D peak) and 1580cm -1 A carbon characteristic peak appears at (G peak); (3) Elemental analysis: The carbon mass fraction of carbonized bamboo baseline material 8 is not less than 70wt%, which is significantly higher than that of uncarbonized bamboo material (carbon content of about 45wt% to 50wt%). Any of the above methods can be used as the technical basis for judging whether bamboo baseline material 8 has been carbonized.

[0060] The "adsorption active layer 5" described in this specification refers to a functional layer attached to the surface and pores of the packing material. This layer contains iron oxides and lanthanum oxides (including but not limited to Fe2O3, FeOOH, La2O3, LaOOH) or exists in the form of iron-lanthanum composite oxides. Identification methods: X-ray fluorescence spectroscopy (XRF) is used to determine the content and distribution of iron and lanthanum elements in the packing material; XRD is used to characterize the oxide crystal phase; and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) is used to observe the distribution morphology of the adsorption active layer on the surface and within the pores of the packing material. The above characterization results can serve as the technical basis for determining product identity in infringement determinations.

[0061] The phrase "at least part of the filament bundles are fixed to the core rope" in this specification means that the number of filament bundles fixed to the core rope 1 is not less than 20% of the total number of filament bundles in the outer covering layer 2, or that the distribution of the fixed filament bundles is sufficient to keep the overall shape of the outer covering layer 2 stable under the conditions of water flow scouring and aeration disturbance, without overall detachment or slippage; the judgment method is: under normal aeration operation conditions, the outer covering layer 2 as a whole does not experience axial slippage or circumferential detachment.

[0062] The “gap” between the outer covering layer 2 and the core rope 1 as described in this specification refers to the open space naturally formed by the free extension of the filament bundle. The criterion for judgment is: under normal water treatment operation conditions, at least a part of the outer surface of the core rope 1 is not completely covered and compacted by the outer covering layer 2, maintaining an open structure through which water can flow radially.

[0063] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection; the scope of protection of the present invention is defined by the claims.

[0064] Example 1 (Core-outer composite - core fiber and outer bamboo strips)

[0065] like Figure 7 As shown, a method for preparing a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0066] (1) Raw material preparation: Bamboo fiber yarn is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 1.5mm; bamboo strips are bamboo green strips after removing the bamboo yellow, soaked in warm water for 3 hours, with a width of 20mm and a thickness of 0.1mm;

[0067] (2) Molding:

[0068] Seven bamboo fiber threads are combined by a twisting machine and then twisted by a twisting machine at 250 twists / meter to form a core rope 1 with a diameter of about 10.5 mm. The outer covering layer 2 is made of bamboo strip bundles obtained in step (1). The bamboo strip bundles are loosely spirally wrapped around the outer periphery of the core rope 1. Bamboo fiber filler 7 is filled in the gap between the outer periphery of the core rope 1 and the outer covering layer 2, and intertwined and fixed with the bamboo fiber bundles of the outer covering layer 2 to form a fluffy structure with a total diameter of about 54 mm, thus obtaining a core-outer composite structure semi-finished product. A plastic buckle is installed on the top as a fixed installation structure 3.

[0069] (3) Carbonization: The semi-finished packing is heated to 500℃ at 7℃ / min under a protective nitrogen atmosphere and held for 3h to obtain carbonized packing;

[0070] (4) Modification: The carbonized filler was immersed in a solution of FeCl3 and La(NO3)3 metal salts with a Fe:La molar ratio of 1:2 and a total metal ion concentration of 0.5 mol / L. After immersion at normal pressure for 2 h, it was taken out, dried at 90℃ for 2 h, and then calcined at 400℃ for 2 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0071] Example 2 (Core-outer composite - core-strip outer fiber)

[0072] like Figure 5 and Figure 6The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0073] (1) Raw material preparation: The bamboo strips are bamboo green strips after removing the bamboo yellow, soaked in warm water for 3 hours, with a width of 5mm and a thickness of 0.5mm; the bamboo fiber thread is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 0.5mm; (2) Molding: Several bamboo strips are combined by a wire-jointing machine and then twisted into a core rope 1 by a twisting machine. The outer covering layer 2 is made of bamboo fiber bundles, loosely clamped and fixed to the outer periphery of the core rope 1. The bamboo fiber filler 7 is filled in the gap between the outer periphery of the core rope 1 and the outer covering layer 2, and intertwined and fixed with the bamboo fiber bundles of the outer covering layer 2 to form a fluffy structure, resulting in a core-outer composite structure semi-finished product. A plastic buckle is installed on the top as a fixed installation structure 3;

[0074] (3) Carbonization: The semi-finished packing is heated to 500℃ at 7℃ / min under a protective argon atmosphere and held for 3h to obtain carbonized packing;

[0075] (4) Modification: The carbonized filler was immersed in a solution of Fe(NO3)3 and La(NO3)3 metal salts. The Fe:La molar ratio was 3:1 and the total metal ion concentration was 0.7 mol / L. After ultrasonic assisted impregnation for 2 h, it was taken out, dried at 120℃ for 1 h, and then calcined at 400℃ for 2 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0076] The structure utilizes bamboo strip core rope to improve axial suspension strength, while using outer bamboo fiber bundles to provide space for film attachment.

[0077] Example 3 (Core-outer composite - core fiber and outer fiber)

[0078] like Figure 1 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0079] (1) Raw material preparation: Bamboo fiber yarn is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 0.5 mm; bamboo strips are bamboo green strips after removing bamboo yellow, soaked in warm water for 4 hours, with a width of 3 mm and a thickness of 0.4 mm;

[0080] (2) Molding:

[0081] Eight bamboo fiber strands are combined by a twisting machine and then twisted into a core rope 1 with a diameter of about 4 mm by a twisting machine at 250 twists / meter. The outer covering layer 2 is made of bamboo strip bundles obtained in step (1), which are loosely bound and wrapped around the outer periphery of the core rope 1 in segments. Bamboo fiber filler 7 is filled in the gap between the outer periphery of the core rope 1 and the outer covering layer 2, and is interwoven and fixed with the bamboo fiber bundles of the outer covering layer 2 to form a fluffy structure with a total diameter of about 20 mm, thus obtaining a core-outer composite structure semi-finished product. A metal hook is installed on the top as a fixed installation structure 3.

[0082] (3) Carbonization: The filler semi-finished product is heated to 650℃ at 5℃ / min under a vacuum of 900Pa and held for 2h to obtain carbonized filler;

[0083] (4) Modification: The carbonized filler was immersed in a solution of metal salts FeCl3, Fe(NO3)3, FeSO4 and La(NO3)3 with a Fe:La molar ratio of 2:1 and a total metal ion concentration of 0.5 mol / L. After ultrasonic assisted impregnation for 3 h, it was taken out, dried at 80℃ for 2 h, and then calcined at 380℃ for 3 h to obtain bamboo-based biofilm filler with adsorption active layer 5. The specific surface area of ​​the core-external composite structure obtained is about 25% higher than that of pure bamboo strip filler, and the phosphorus adsorption capacity is about 31 mg / g. It is suitable for various water treatment conditions.

[0084] The above performance data are experimentally determined values, and the actual values ​​may vary depending on the batch of raw materials, process conditions, and operating environment.

[0085] Example 4 (Core-outer composite - core fiber and outer bamboo strips)

[0086] like Figure 1 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0087] (1) Raw material preparation: Bamboo fiber yarn is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 0.1 mm; bamboo strips are bamboo green strips after removing bamboo yellow, soaked in warm water for 5 hours, with a width of 1 mm and a thickness of 3 mm;

[0088] (2) Molding:

[0089] Seven bamboo fiber strands are combined by a spinning machine and then twisted by a twisting machine at 250 twists / meter to form a core rope 1 with a diameter of about 2-3 mm. The outer covering layer 2 is made of bamboo strip bundles obtained in step (1), which are loosely wrapped around the outer periphery of the core rope 1. Bamboo fiber filler 7 is filled in the gap between the outer periphery of the core rope 1 and the outer covering layer 2, and is interwoven and fixed with the bamboo fiber bundles of the outer covering layer 2 to form a fluffy structure with a total diameter of about 20 mm, thus obtaining a core-outer composite structure semi-finished product. A stainless steel ring is installed on the top as a fixed installation structure 3.

[0090] (3) Carbonization: The filler semi-finished product is heated to 900℃ at 5℃ / min under vacuum of 800Pa and kept at the temperature for 1h to obtain carbonized filler;

[0091] (4) Modification: The carbonized filler was immersed in a solution of FeCl3, Fe(NO3)3 and La(NO3)3 metal salts. The Fe:La molar ratio was 2:1 and the total metal ion concentration was 0.5 mol / L. After immersion at normal pressure for 5 h, it was taken out, dried at 70℃ for 2 h, and then calcined at 350℃ for 3 h to obtain the bamboo-based biofilm filler with adsorption active layer 5.

[0092] Example 5 (Wrapped and Dispersed Type)

[0093] like Figure 10 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0094] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.8 mm;

[0095] (2) Molding:

[0096] Two bamboo fiber core ropes 1, each pre-twisted from 16 bamboo fiber strands and approximately 24 mm in diameter, are used as the central core 14. A large number of loose bamboo fiber bundles with a diameter of 0.5 mm are spirally wound and distributed around the central core 14 as the outer covering layer 2 using machine weaving and winding. The ends of the bundles are freely dispersed and fluffed to form a ring-shaped radial distribution of the bundles, forming a fluffy body with a total diameter of 80 mm. This results in a semi-finished product with a wound and fluffy structure. The top is fixed and installed using a rope end binding structure 3.

[0097] (3) Carbonization: The semi-finished packing is heated to 300℃ at 9℃ / min under a protective helium atmosphere and held for 3h to obtain carbonized packing;

[0098] (4) Modification: The carbonized filler was immersed in a solution of metal salts of FeCl3, Fe(NO3)3, FeSO4 and La(NO3)3, LaCl3 and La2(SO4)3. The Fe:La molar ratio was 1:1 and the total metal ion concentration was 0.6 mol / L. After immersion at normal pressure and with ultrasonic assistance for 1 h each, it was taken out, dried at 70℃ for 2 h, and then calcined at 400℃ for 0.5 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0099] Example 6 (Wrapped and Dispersed Type)

[0100] like Figure 10 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0101] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.5 mm;

[0102] (2) Molding:

[0103] Two strands of bamboo fiber core rope 1, each pre-twisted from 20 bamboo fiber strands, with a diameter of 18mm, are used as the central core 14. A large number of loose bamboo fiber strands with a diameter of 0.6mm are spirally wound and distributed around the central core 14 as the outer covering layer 2 using machine weaving and winding. The ends of the strands are freely dispersed and fluffed to form a ring-shaped radial distribution of strands, forming a fluffy body with a total diameter of 60mm, resulting in a semi-finished product with a wound and fluffy structure. The top bamboo fiber rope knot serves as a fixed installation structure 3.

[0104] (3) Carbonization: The semi-finished packing is heated to 650℃ at 2℃ / min under protective argon and held for 1.5h to obtain carbonized packing;

[0105] (4) Modification: The carbonized packing was immersed in a solution of FeCl3 and metal salts of La(NO3)3, LaCl3 and La2(SO4)3 with a Fe:La molar ratio of 3:1 and a total metal ion concentration of 0.4 mol / L. After immersion at normal pressure for 4 hours, it was taken out, dried at 80℃ for 1 hour, and then calcined at 360℃ for 2.5 hours to obtain bamboo-based biofilm packing with adsorption active layer 5. The resulting entangled and dispersed filament bundles are distributed in a ring-shaped radial pattern, with a large specific surface area and good water flow penetration. It is suitable for municipal sewage treatment plants and large bioreactors. The effective suspension length can reach 6000 mm. The adsorption capacity of the obtained packing for phosphate is about 31 mg / g and the tensile strength is 45 N.

[0106] The above performance data are experimentally determined values, and the actual values ​​may vary depending on the batch of raw materials, process conditions, and operating environment.

[0107] Example 7 (Wrapped and Dispersed Type)

[0108] like Figure 10 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0109] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 1mm;

[0110] (2) Molding:

[0111] A bamboo fiber core rope 1, which is made of 16 bamboo fiber threads twisted together and has a diameter of about 15mm, is used as the central core 14. A large number of loose bamboo fiber bundles with a diameter of 0.8mm are spirally wound and distributed around the central core 14 as the outer covering layer 2 by machine weaving and winding. After fluffing treatment, the bundles are distributed in a ring-shaped radial pattern to form a fluffy body with a total diameter of 80mm. The semi-finished product with a winding and scattered structure is obtained. A stainless steel ring is installed on the top as a fixed installation structure 3.

[0112] (3) Carbonization: The semi-finished packing is heated to 300℃ at 5℃ / min under vacuum conditions of 1000Pa in the furnace and held for 3h to obtain carbonized packing.

[0113] (4) Modification: The carbonized filler was immersed in a solution of FeSO4 and metal salts of La(NO3)3 and LaCl3 with a Fe:La molar ratio of 4:1 and a total metal ion concentration of 0.4 mol / L. After ultrasonic assisted impregnation for 5 h, it was taken out, dried at 90℃ for 2 h, and then calcined at 350℃ for 3 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0114] Example 8 (Loose, scattered structure)

[0115] like Figure 13 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0116] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.4 mm;

[0117] (2) Molding:

[0118] 15 bamboo fiber threads prepared in step (1) are twisted into a twisted core rope 1 with a diameter of 6.8 mm as the central skeleton. A large number of loose bamboo fiber bundles with a length of 100 mm prepared in step (1) are irregularly wrapped around the outer periphery of the core rope 1. After being fluffed by airflow, the bundles are made to be freely curled and protruding in a ring shape on the outer periphery of the core rope 1, forming a fluffy and scattered layer 19 with a total diameter of 80 mm to obtain a fluffy and scattered structure semi-finished product. A metal hook is installed on the top as a fixed installation structure 3.

[0119] (3) Carbonization: The filler semi-finished product is heated to 300℃ at 8℃ / min under vacuum of 800Pa and kept at the temperature for 3h to obtain carbonized filler;

[0120] (4) Modification: The carbonized filler was immersed in a solution of FeCl3 and metal salts of La(NO3)3 and La2(SO4)3 with a Fe:La molar ratio of 2:1 and a total metal ion concentration of 0.5 mol / L. After immersion at normal pressure for 5 h, it was taken out, dried at 70℃ for 2 h, and then calcined at 350℃ for 3 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0121] Example 9 (Loose, scattered structure)

[0122] like Figure 13 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0123] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.5 mm;

[0124] (2) Molding:

[0125] Twist 14 bamboo fiber threads prepared in step (1) into a twisted core rope 1 with a diameter of 6mm as the central skeleton. Wrap a large number of loose bamboo fiber bundles with a length of 130mm prepared in step (1) around the core rope 1 in an irregular manner. Then, airflow fluffing treatment is applied to make the bundles freely curled and protruding in a ring shape around the core rope 1, forming a fluffy and scattered layer (19) with a total diameter of 90mm to obtain a fluffy and scattered structure semi-finished product. A plastic buckle is installed on the top as a fixed installation structure 3.

[0126] (3) Carbonization: The semi-finished packing is heated to 600℃ at 5℃ / min under a protective argon atmosphere and held for 2h to obtain carbonized packing;

[0127] (4) Modification: The carbonized filler was immersed in a solution of metal salts of Fe(NO3)3, FeSO4 and LaCl3, La2(SO4)3 with a Fe:La molar ratio of 1:1 and a total metal ion concentration of 0.6 mol / L. After immersion in the solution for 5 h under a vacuum of -0.08 MPa, it was taken out, dried at 80℃ for 2 h, and then calcined at 400℃ for 2 h to obtain bamboo-based biofilm filler with adsorption active layer 5. The resulting loose and dispersed structure has a significantly increased specific surface area, fast biofilm formation, and low water flow resistance. It is suitable for the treatment of high-concentration organic wastewater. The effective suspension length can reach 6000 mm. The adsorption capacity of the obtained filler for phosphate is about 34 mg / g.

[0128] The above performance data are experimentally determined values, and the actual values ​​may vary depending on the batch of raw materials, process conditions, and operating environment.

[0129] Example 10 (Loose, scattered structure)

[0130] like Figure 13The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0131] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.4 mm;

[0132] (2) Molding:

[0133] The 16 bamboo fiber threads prepared in step (1) are twisted into a twisted core rope 1 with a diameter of 6mm as the central skeleton. A large number of loose bamboo fiber bundles with a length of 150mm prepared in step (1) are irregularly wrapped around the outer periphery of the core rope 1. After being fluffed by airflow, the bundles are made to be freely curled and protruding in a ring shape on the outer periphery of the core rope 1, forming a fluffy and scattered layer (19) with a total diameter of 80mm to obtain a fluffy and scattered structure semi-finished product. A plastic buckle is installed on the top as a fixed installation structure 3.

[0134] (3) Carbonization: The semi-finished packing is heated to 300℃ at 2℃ / min under a protective nitrogen, argon or helium atmosphere or a vacuum of 1000Pa, and carbonized for 3h to obtain carbonized packing.

[0135] (4) Modification: The carbonized filler was immersed in a solution of FeCl3, FeSO4 and La(NO3)3 metal salts. The Fe:La molar ratio was 1:2 and the total metal ion concentration was 0.5 mol / L. After ultrasonic assisted impregnation for 2 h, it was taken out, dried at 90℃ for 1 h, and then calcined at 400℃ for 2 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0136] Example 11 (Solid Twisted Structure)

[0137] like Figure 11 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0138] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 1.5 mm;

[0139] (2) Molding:

[0140] Two pre-twisted bamboo fiber core ropes 1 are used. Each core rope 1 is made of 12 bamboo fiber threads twisted together to form a braiding skeleton. The remaining bamboo fiber threads are used as filler yarns. The whole structure is woven into a solid twisted body with a waterweed rope shape by a simple braiding machine. Loose bamboo fiber yarns are left to be freely and loosely distributed on the outer periphery to form a braided rope bundle with a total diameter of 60mm, resulting in a solid twisted structure semi-finished product. The top is tied to form a fixed installation structure 3.

[0141] (3) Carbonization: The filler semi-finished product is heated to 900℃ at 7℃ / min under vacuum of 800Pa and kept at the temperature for 1h to obtain carbonized filler;

[0142] (4) Modification: The carbonized filler was immersed in a solution of FeSO4 and metal salts of La(NO3)3 and La2(SO4)3 with a Fe:La molar ratio of 3:1 and a total metal ion concentration of 0.4 mol / L. After ultrasonic assisted impregnation for 2 h, it was taken out, dried at 90℃ for 1 h, and then calcined at 400℃ for 2 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0143] Example 12 (Solid Twisted Structure)

[0144] like Figure 11 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0145] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.5 mm;

[0146] (2) Molding:

[0147] Three pre-twisted bamboo fiber core ropes 1 are used. Each core rope 1 is made of 10 bamboo fiber threads twisted together to form a braiding skeleton. The remaining bamboo fiber threads are used as filler yarns. The whole structure is woven into a solid twisted body with a waterweed rope shape by a simple braiding machine. Loose bamboo fiber yarns are left to be freely and loosely distributed on the outer periphery to form a braided rope bundle with a total diameter of 50mm. The solid twisted structure semi-finished product is obtained. A plastic buckle is installed on the top as a fixed installation structure 3.

[0148] (3) Carbonization: The packing semi-finished product is heated to 650℃ at 7℃ / min under a protective helium atmosphere and held for 2h to carbonize it, thus obtaining carbonized packing;

[0149] (4) Modification: The carbonized packing was immersed in a solution of metal salts of FeCl3, Fe(NO3)3, FeSO4 and LaCl3, La2(SO4)3 with a Fe:La molar ratio of 2:1 and a total metal ion concentration of 0.5 mol / L. After immersion at normal pressure for 3 h, it was removed, dried at 70℃ for 2 h, and then calcined at 390℃ for 3 h to obtain bamboo-based biofilm packing with an adsorption active layer 5. The resulting solid twisted structure was woven with a density controlled between tight and medium weave, allowing water flow to penetrate to the central area. After high-temperature carbonization and iron-lanthanum modification, the core rope 1 and the filling filament bundle combined the central support strength and the peripheral biofilm space, making it suitable for rural decentralized sewage treatment purification tanks 4 with an effective suspension length of 2000-4000 mm. The adsorption capacity of the obtained packing for phosphate was about 33 mg / g.

[0150] The above performance data are experimentally determined values, and the actual values ​​may vary depending on the batch of raw materials, process conditions, and operating environment.

[0151] Example 13 (Solid Twisted Structure)

[0152] like Figure 11 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0153] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.8 mm;

[0154] (2) Molding:

[0155] Four pre-twisted bamboo fiber core ropes 1, each core rope 1 consisting of eight bamboo fiber threads twisted together to form a braiding skeleton, with the remaining bamboo fiber threads serving as filler bundles, are braided into a solid twisted body with an overall imitation seaweed rope-like structure using a simple braiding machine. Loose bamboo fiber bundles are left to be freely and loosely distributed on the outer periphery, forming a braided rope bundle with a total diameter of 40mm, resulting in a solid twisted structure semi-finished product. A stainless steel ring is provided at the top for hanging and fixing installation structure 3.

[0156] (3) Carbonization: The filler semi-finished product is heated to 300℃ at 4℃ / min under a vacuum of 1000Pa and kept at the temperature for 3h to obtain carbonized filler;

[0157] (4) Modification: The carbonized filler is immersed in FeCl3, FeSO4 and La(NO3)3, LaCl 3、 The solution of La2(SO4)3 metal salt has a Fe:La molar ratio of 0.5:1 and a total metal ion concentration of 0.3 mol / L. After ultrasonic-assisted impregnation for 5 h, the solution is removed, dried at 70 °C for 2 h, and then calcined at 350 °C for 3 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0158] Example 14 (Multi-strand twisted structure)

[0159] like Figure 12 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0160] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.8 mm;

[0161] (2) Molding:

[0162] (a) Bamboo fiber twisted yarn and bamboo strips (6) are made into fillers with core rope and outer covering layer as in Example 1 (core fiber outer strip), Example 5 (winding and spreading structure), Example 8 (fluffy spreading structure), and Example 11 (solid twisted structure);

[0163] (b) The fillers prepared above are twisted into a twisted body in groups of at least two and at most eight, resulting in a multi-strand twisted semi-finished product;

[0164] (3) Carbonization: The semi-finished packing is heated to 800℃ at 7℃ / min under a protective argon atmosphere and held for 0.5h to obtain carbonized packing;

[0165] (4) Modification: The carbonized filler was immersed in a solution of FeSO4 and metal salts of LaCl3 and La2(SO4)3 with a Fe:La molar ratio of 3:1 and a total metal ion concentration of 0.6 mol / L. After immersion at normal pressure for 3 h, it was taken out, dried at 100℃ for 1 h, and then calcined at 420℃ for 3 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0166] Example 15 (Multi-strand twisted structure)

[0167] like Figure 12 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0168] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.8mm; bamboo strips are bamboo strips with the yellow part removed, with a width of 12mm and a thickness of 0.9mm;

[0169] (2) Molding:

[0170] (a) Bamboo fiber twisted yarn and bamboo strips (6) are made into fillers with core rope and outer covering layer as in Example 2 (core and outer fiber), Example 5 (wound and scattered structure), Example 8 (fluffy and scattered structure), and Example 11 (solid twisted structure);

[0171] (b) The fillers prepared above are twisted into a twisted body in groups of at least two and at most eight, resulting in a multi-strand twisted semi-finished product;

[0172] (3) Carbonization: The semi-finished packing is heated to 600℃ at 9℃ / min under a protective argon atmosphere and held for 3h to obtain carbonized packing;

[0173] (4) Modification: The carbonized filler was immersed in a solution of metal salts of FeCl3, Fe(NO3)3 and LaCl3 with a Fe:La molar ratio of 2:1 and a total metal ion concentration of 0.5 mol / L. After immersion at normal pressure for 3 h, it was taken out (when at least one of them is a core-fiber structure, the immersion time is 40 h), dried at 120℃ for 1 h, and then calcined at 500℃ for 0.5 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0174] Example 16 (Multi-strand twisted structure)

[0175] like Figure 12 The preparation method of a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants includes the following steps:

[0176] (1) Raw material preparation: Bamboo fiber yarn is made from raw materials of Bambusoideae plants through mechanical separation and twisting, with a diameter of 0.8mm; bamboo strips are bamboo strips with the yellow part removed, with a width of 12mm and a thickness of 0.9mm;

[0177] (2) Molding:

[0178] (a) Bamboo fiber twisted yarn and bamboo strips (6) are made into fillers with core rope and outer covering layer as in Examples 1, 5, 8 and 11;

[0179] (b) The fillers prepared above are twisted into a twisted body in groups of at least two and at most eight, resulting in a multi-strand twisted semi-finished product;

[0180] (3) Carbonization: The semi-finished packing is heated to 500℃ at 2℃ / min under a protective argon atmosphere and held for 0.5h to obtain carbonized packing;

[0181] (4) Modification: The carbonized filler was immersed in a solution of metal salts of FeCl3, FeSO4 and LaCl3, La2(SO4)3 with a Fe:La molar ratio of 0.5:1 and a total metal ion concentration of 0.3 mol / L. After ultrasonic assisted impregnation for 3 h, it was taken out, dried at 90℃ for 3 h, and then calcined at 250℃ for 4 h to obtain bamboo-based biofilm filler with adsorption active layer 5.

[0182] Experimental Example (Boundary Parameter Verification)

[0183] The feasibility of the numerical range boundary conditions was verified using a method for preparing a bamboo-based biofilm filler with a rope-like iron-lanthanum modification that mimics aquatic plants.

[0184] (1) Minimum temperature carbonization boundary: The semi-finished filler is heated to 300℃ at 2℃ / min under nitrogen protection and held for 4 hours. At 300℃, the hemicellulose in the bamboo base material has basically decomposed, the cellulose has just begun to pyrolyze, the lignin structure is basically intact, the degree of carbonization is low, the carbon skeleton has not been fully formed, the specific surface area is about 80m² / g-150m² / g, the pore structure is not well developed, but the material retains more original fiber toughness and strong bending resistance. The long-term biofilm load and metal oxide loading sites are relatively limited, which is suitable for low load, short cycle or high requirements for filler flexibility. This temperature is the lower limit of the carbonization process of this invention. Below this temperature, it is difficult for bamboo base materials to form a stable carbon skeleton, which cannot meet the requirements of biological stability in long-term water treatment environment.

[0185] (2) Low-temperature carbonization effect: The filler semi-finished product is heated to 500℃ at 3℃ / min under nitrogen protection and kept at 4h. When carbonized at 500℃, the hemicellulose and cellulose in the bamboo base material are partially pyrolyzed, the lignin begins to soften, the carbon skeleton is initially formed but the porosity is low, and the specific surface area is about 200m² / g-400m² / g. At this time, the filler still retains a certain toughness and can adapt to light water flow scouring. It is suitable for low temperature and low load conditions.

[0186] (3) High-temperature carbonization effect: The filler semi-finished product is heated to 800℃ at 8℃ / min under nitrogen protection and held for 0.5h. When carbonized at 800℃, the bamboo baseline material is completely pyrolyzed, forming a highly graphitized carbon skeleton with a specific surface area of ​​about 600m² / g-900m² / g and a well-developed pore structure, but the brittleness increases significantly. At this time, the filler needs to be matched with a thicker core rope (diameter not less than 10mm) to maintain the suspension strength, which is suitable for high load and high phosphorus concentration conditions.

[0187] (4) Maximum carbonization boundary: The filler semi-finished product is heated to 900℃ at 10℃ / min under nitrogen protection and held for 0.5h. When carbonized at 900℃, the bamboo baseline material undergoes more thorough pyrolysis, and the degree of graphitization is further improved. The specific surface area is about 650m² / g-950m² / g, the pore structure is most developed, and the density of phosphate adsorption sites is high. However, the brittleness of the material reaches the limit that the process of this invention can withstand. The core rope diameter needs to be no less than 12mm and the density of the outer coating layer needs to be appropriately increased to maintain the overall suspension strength. Above this temperature, the risk of carbon skeleton shrinkage and cracking increases significantly, and the molding qualification rate decreases significantly. Therefore, 900℃ is the upper limit of the carbonization process of this invention, which is suitable for high-load conditions with the highest requirements for phosphorus adsorption capacity and can be combined with a thickened core rope structure.

[0188] (5) such as Figure 8 As shown, the large-diameter boundary consists of a core rope formed by twisting 36 strands of bamboo fiber rope, with a core rope diameter of approximately 35mm-40mm (close to the upper limit of the claim); the outer covering layer uses bamboo strips bundled 15mm wide and 2mm thick, forming a filler with a total diameter of approximately 140mm-150mm. The effective suspension length is approximately 7000mm-8000mm. The filling volume of this specification of filler is approximately 15-20 times that of small-diameter fillers, making it suitable for large bioreactors or deep-water aeration tanks.

[0189] (6) Small diameter boundary: The core rope is formed by tightly twisting a single bamboo fiber (diameter of about 0.1mm-0.3mm) to form a core rope with a diameter of about 3mm-5mm; the outer covering layer is made of fine fiber bundles of the same material to form a filler with a total diameter of about 20mm-30mm and an effective suspension length of about 500mm-1000mm, which is suitable for laboratory scale or small purification tanks.

[0190] (7) Iron-Lanthanum Molar Ratio Boundary: Prepare the impregnation solution with a Fe:La molar ratio of 0.5:1 and a total metal ion concentration of 0.1 mol / L. Impregnate multiple times (3-5 times), and dry at 60℃ after each impregnation. A low iron-high lanthanum ratio is beneficial to improve the selective adsorption of phosphate, but the loading is low (about 2wt%-5wt%), which is suitable for long-term operation with low phosphorus concentration. Prepare the impregnation solution with a Fe:La molar ratio of 4:1 and a total metal ion concentration of 1.5 mol / L. Impregnate once, dry rapidly at 120℃ and calcine at 500℃. The loading (about 25wt%-35wt%) is suitable for short-term high-intensity adsorption of high phosphorus wastewater.

[0191] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solutions and concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants, characterized in that: It includes a core rope (1), an outer covering layer (2), a fixing and installation structure (3), and an adsorption active layer (5); The core rope (1) is a rope-shaped core formed by twisting together multiple carbonized bamboo baseline materials (8); The outer covering layer (2) is a fluffy layer composed of several carbonized bamboo base material (8) filament bundles. The outer covering layer (2) surrounds the outer periphery of the core rope (1). The carbonized bamboo base material (8) filament bundles are distributed at intervals along the length direction of the filler. At least one end or middle of a portion of the carbonized bamboo base material (8) filament bundles is fixed to the core rope (1), and the other portion extends radially or obliquely to the core rope (1) to form a free fluffy part. The radial extension length of the free fluffy part is not less than the radius of the core rope (1). A gap is formed between the outer covering layer (2) and the core rope (1) for water to flow through and for biofilm to attach. The adsorption active layer (5) is attached to at least one of the surfaces and pores of the core rope (1) and the outer covering layer (2), and the adsorption active layer (5) contains iron oxide and lanthanum oxide; The fixed installation structure (3) is located at the end of the packing material and is composed of a connector that is fixedly connected to the end of the core rope (1) or the outer covering layer (2), and is used to suspend the packing material on the support of the water treatment device.

2. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The carbonized bamboo baseline material (8) is formed by carbonizing bamboo raw fiber twisted thread, bamboo strip (6) or a combination of the two; the diameter of the bamboo raw fiber twisted thread before carbonization is 0.1mm-1.5mm; the bamboo strip (6) is bamboo green strip after removing the bamboo yellow, and the width before carbonization is 1mm-20mm and the thickness is 0.1mm-3mm.

3. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The molar ratio of iron to lanthanum in the adsorption active layer (5) is 0.5:1-4:1, and the loading of the adsorption active layer (5) relative to the dry weight of the filler is 2wt%-35wt%.

4. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The diameter of the core rope (1) is 3mm-40mm, the total diameter of the filler is 20mm-150mm, and the diameter of the core rope (1) is not greater than half of the total diameter of the filler.

5. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The free fluffy portion extends 5mm-80mm from the outer surface of the core rope (1), and the distance between adjacent free fluffy portions along the length direction of the filler is 5mm-100mm.

6. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The core rope (1) is a twisted rope made of carbonized bamboo strips (6), a twisted rope made of carbonized bamboo raw fibers, or a combination thereof. The outer covering layer (2) is a loose layer of carbonized bamboo raw fiber bundles, a loose layer of carbonized bamboo strips (6) bundles, or a combination thereof, forming a core-fiber outer fiber structure, a core-fiber outer strip structure, or a mixed weaving structure.

7. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The outer covering layer (2) is fixed to the outer periphery of the core rope (1) by one or more of the following methods: spiral winding, segmented binding, annular winding, or clamping fixation.

8. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The fixed installation structure (3) is one or more of the following: stainless steel ring, bamboo fiber knot, plastic buckle, metal hook or rope end binding structure.

9. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The effective suspension length of the packing is 500mm-8000mm.

10. The imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler according to claim 1, characterized in that: The filler is one of the following: a wound and dispersed structure, a loose and dispersed structure, a solid twisted structure, or a multi-strand twisted structure.

11. A method for preparing a bamboo-based biofilm filler with iron-lanthanum modified in the shape of aquatic plants, characterized in that, Includes the following steps: (1) Raw material preparation: Bamboo fiber twisted yarn is made from bamboo subfamily plant raw materials through mechanical separation and twisting, with a diameter of 0.1-1.5mm; bamboo strips are bamboo green strips after removing bamboo yellow, with a width of 1-20mm and a thickness of 0.1-3mm; (2) Molding: Bamboo fiber twisted yarn is woven, wound or assembled with bamboo strips (6) into a rope-like structure resembling aquatic plants to obtain a filler semi-finished product; (3) Carbonization: The semi-finished packing is carbonized by heating it to 300-900℃ in a protective atmosphere or vacuum at a rate of 1℃ / min-10℃ / min and holding it at that temperature for 0.5h-4h to obtain carbonized packing. (4) Modification: The carbonized filler is immersed in a metal salt solution containing iron salt and lanthanum salt, and is immersed for 2-48 hours under normal pressure, negative pressure or ultrasonic-assisted impregnation. After immersion, it is taken out, dried at 60℃-120℃ for 1-3 hours, and then calcined at 250℃-500℃ for 0.5-4 hours to obtain bamboo-based biofilm filler with adsorption active layer (5).

12. The preparation method of the imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler as described in claim 11, characterized in that: The protective atmosphere in step (3) is: an inert gas including one or more of nitrogen, argon or helium; the vacuum condition is a negative pressure environment with an internal furnace pressure of 800-1000 Pa.

13. The preparation method of the imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler as described in claim 11, characterized in that: In step (4), when the core rope (1) and the outer covering layer (2) are bamboo strips (6), the soaking time is 4-48h.

14. The preparation method of the imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler as described in claim 11, characterized in that: The iron salt mentioned in step (4) is one or more of FeCl3, Fe(NO3)3 or FeSO4.

15. The preparation method of the imitation aquatic plant rope-like iron-lanthanum modified bamboo-based biofilm filler as described in claim 11, characterized in that: The lanthanum salt mentioned in step (4) is one or more of La(NO3)3, LaCl3 or La2(SO4)3.

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