Preparation method of activated charcoal composite gel material and application method of activated charcoal composite gel material in antibiotic wastewater treatment

Abstract

The invention particularly relates to preparation of an activated charcoal composite gel material and an application method of the activated charcoal composite gel material in antibiotic wastewater treatment, and belongs to the technical field of industrial wastewater treatment materials. The preparation method comprises the following steps: preparing KOH activated biochar by taking biomass solid waste as a raw material, adding sodium alginate, stirring, heating and continuously stirring, dripping the obtained solution into a calcium chloride solution, hardening and cleaning to obtain the activated biochar composite gel ball. The gel material is used for antibiotic wastewater treatment and has extremely high antibiotic adsorption performance. Activated charcoal and a gel material preparation technology are combined, the activated charcoal composite gel material with remarkable antibiotic adsorption performance is obtained, the adsorbent is stable in property, convenient to prepare, high in adsorption rate and excellent in reutilization performance, the antibiotic adsorption performance is remarkably superior to that of similar systems, and the activated charcoal composite gel material is suitable for industrial application and popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial wastewater treatment materials, and particularly relates to a preparation method of an activated biochar composite gel material and its application method in antibiotic wastewater treatment. Background Art

[0003] As a new type of adsorption material, biochar has the advantages of large specific surface area, rich pore structure, diverse surface functional groups, etc., and shows great potential in the field of environmental remediation. Agricultural solid wastes include crop straws, agricultural product processing wastes, livestock and poultry manures, etc., which contain a large amount of energy and nutrients. Preparing biochar is an important way to utilize agricultural solid wastes. The adsorption performance of conventional biochar for antibiotics is relatively low, while activated biochar has higher antibiotic adsorption performance. Sodium alginate is a natural polysaccharide with good biocompatibility, degradability and gel properties, and is often used as the matrix of gel materials. Combining activated biochar with sodium alginate can integrate the advantages of both and prepare an adsorption material with excellent performance. However, the adsorption performance and reusability of the activated biochar composite gel materials currently used in antibiotic wastewater treatment need to be improved, and the cost is relatively high, making it difficult to be popularized and applied on a large scale.

[0004] In addition, during the preparation of the activated biochar composite gel material, it needs to be prepared under the protection of nitrogen. However, during the preparation process, air easily enters the reaction kettle through the feed inlet, thus affecting the preparation of the activated biochar composite gel material. In addition, the process for preparing the activated biochar composite gel material involves many types of equipment, and the materials need to be transferred between multiple devices, which is not only cumbersome to operate but also causes more losses during this process, affecting production efficiency and quality.

[0005] In view of this, a preparation method of the activated biochar composite gel material and its application method in antibiotic wastewater treatment are provided. Summary of the Invention

[0006] In view of the problems in the existing biochar adsorption method that the adsorption performance of the original biochar is limited and it is difficult to meet the actual application requirements, and the adsorption performance and reusability of the existing activated biochar composite gel materials need to be improved, and the preparation cost is relatively high and it is difficult to be popularized and applied on a large scale, the present invention provides a preparation process of an activated biochar composite gel material with simple preparation process and low cost and its application method in antibiotic wastewater treatment. The material can improve the adsorption performance and reusability of the activated biochar when applied to antibiotic wastewater treatment.

[0007] To achieve the above object, the present invention provides the following technical solution: A preparation method of an activated biochar composite gel material, comprising the following steps: S1: Preparation of activated biochar: Crush the biomass solid waste after screening and removing impurities to a particle size less than 5 mm, and dry it to a constant weight; Place the dried biomass raw material in a reaction device for the first high-temperature pyrolysis, and then naturally cool it to room temperature to obtain biochar; Mix the biochar and KOH according to the mass ratio, and grind them until uniform; Place the uniformly mixed material in the reaction device for the second high-temperature pyrolysis, with a cooling rate of 5 °C / min, cool down to 300 - 600 °C, and then naturally cool it to room temperature; Add 1 mol / L HCl solution with the same molar amount as KOH to the pyrolyzed material, stir for 1 h, then wash it with deionized water until neutral, and dry it to a constant weight to obtain activated biochar; S2: Preparation of activated biochar composite gel material: Dissolve sodium alginate in deionized water to prepare an aqueous sodium alginate solution; Add the above aqueous sodium alginate solution to the activated biochar prepared in step S1 at a ratio of 5% - 20% by mass fraction, stir and heat up to 50 - 90 °C, and keep it for 30 min; Continuously stir the above mixed solution at a speed of 1000 - 2000 rpm for 12 - 48 h; Slowly drop the stirred mixed solution into a CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads; Let the gel beads harden in the CaCl2 solution for 24 h, and then wash them clean with deionized water to obtain the activated biochar composite gel material.

[0008] As a further scheme of the present invention: The biomass solid waste described in step S1 is any one or a combination of several of straw, wood chips, and fruit shells; The first high-temperature pyrolysis described in step S1 means heating to 400 - 600 °C at a heating rate of 2 - 10 °C / min in a nitrogen atmosphere and keeping it for 1 - 5 h; The mass ratio of the biochar and KOH described in step S1 is (1:0.5) - (1:6); The second high-temperature pyrolysis described in step S1 means heating to 600 - 900 °C at a heating rate of 3 - 10 °C / min in a nitrogen atmosphere and keeping it for 1 - 4 h; The preparation of the aqueous sodium alginate solution described in step S2 is an aqueous sodium alginate solution with a mass fraction of 2% - 4%; The concentration of the CaCl2 solution described in step S2 is 2% - 4% by mass fraction.

[0009] As a further solution of the present invention: The reaction device includes a reaction kettle, the bottom end of the reaction kettle is provided with a discharge port, a valve is installed on the outer wall of the discharge port, a heat-conducting oil coil is installed on the outer wall of the reaction kettle, and an oil outlet and an oil inlet are respectively arranged at both ends of the heat-conducting oil coil. An intake pipe and an exhaust pipe are respectively connected to both sides of the outer wall of the reaction kettle. Materials enter the reaction kettle and are subjected to grinding and stirring operations through a grinding mechanism. Solid materials enter the reaction kettle through a solid feeding mechanism, and liquid materials enter the reaction kettle through a liquid feeding mechanism; the grinding mechanism includes a grinding chamber, and the grinding chamber is opened inside the reaction kettle; a connecting groove is opened at the bottom end of the grinding chamber, and a water washing and drying chamber and a stirring chamber are sequentially arranged at the bottom end of the connecting groove.

[0010] As a further solution of the present invention: The top end of the reaction kettle is fixedly connected with a mounting frame, a hydraulic cylinder is installed on the top end of the mounting frame, the output end of the hydraulic cylinder is connected with a connecting seat, the bottom end of the connecting seat is rotatably connected with a tooth column, and a motor is installed below the mounting frame at the top end of the reaction kettle. The output end of the motor is connected with a first straight gear, the first straight gear is in contact with the tooth column, the bottom end of the tooth column is fixedly connected with a rotating seat located inside the grinding chamber, the bottom end of the rotating seat is fixedly connected with a connecting column, the bottom end of the connecting column is fixedly connected with a shielding column, a square guide sleeve is fixedly connected below the shielding column, and the outer wall of the rotating seat is fixedly connected with a first grinding frame. The bottom end of the inner wall of the grinding chamber is fixedly connected with a second grinding frame; A high-temperature electric heating device is arranged in the grinding chamber below the first grinding frame and in the rotating seat above the second grinding frame. The high-temperature electric heating device is an annular electric heating rod or an electric heating ceramic plate; The lower part of the water washing and drying chamber is in the shape of an inverted frustum with a large top and a small bottom, and more than one switching valve is arranged on the circular bottom surface of the water washing and drying chamber; The square guide sleeve extends downward into the water washing and drying chamber, and the outer wall of the square guide sleeve located inside the water washing and drying chamber is connected with a conical filter screen; The inner wall of the stirring chamber is fixedly connected with a mounting plate, and a stirring shaft is rotatably connected inside the mounting plate. The stirring shaft includes a rotating shaft part, a cross bar part and a wall scraping rod. The rotating shaft part is connected to the wall scraping rod through the cross bar part, and the wall scraping rod is attached to the inner wall of the stirring chamber; The upper end of the rotating shaft part extends upward and enters the water washing and drying chamber and then slides into the square guide sleeve, and the cross-sectional shape of the inserted section of the rotating shaft part and the square guide sleeve is square.

[0011] As a further solution of the present invention: The solid feeding mechanism includes a solid feeding port, which is fixedly connected to the outer wall of the reaction kettle and located above the exhaust pipe. The top of the solid feeding port is sleeved with a cover body. A fixing groove is provided on the outer wall of one side of the solid feeding port. A fixing block extending into the inner cavity of the cover body is slidably connected inside the cover body. A first spring is connected between the fixing block and the cover body. An extrusion block is slidably connected to the inside of the cover body at the top of the fixing block. A rotating block is rotatably connected to the top of the cover body. A first threaded rod is fixedly connected to the bottom end of the rotating block, and the first threaded rod extends into the extrusion block. A rotating plate is rotatably connected to the inner wall of the exhaust pipe. One end of the rotating plate is fixedly connected to a connecting shaft, and one end of the connecting shaft is fixedly connected to a second straight gear. The second straight gear is rotatably connected inside the solid feeding port. A pressing frame is slidably connected to the outside of the second straight gear inside the solid feeding port. A second spring is connected between the bottom end of the pressing frame and the solid feeding port. The pressing frame extends above the solid feeding port.

[0012] As a further solution of the present invention: The liquid feeding mechanism includes a liquid feeding port, which is arranged above the air inlet pipe. The bottom end of the liquid feeding port is fixedly connected with a liquid inlet pipe, and the bottom end of the liquid inlet pipe is fixedly connected to the reaction kettle. A lower baffle is arranged at the bottom end of the inner wall of the liquid feeding port. A second threaded rod penetrating through the lower baffle is rotatably connected inside the liquid feeding port. A first bevel gear is fixedly connected to the bottom end of the second threaded rod. A second bevel gear is rotatably connected to the outside of the first bevel gear inside the liquid feeding port. One end of the second bevel gear is fixedly connected with a third threaded rod, and one end of the third threaded rod is fixedly connected with a rotating column. A pressing plate is slidably connected to the outer wall of the third threaded rod. A clamping groove is provided on one side of the inner wall of the liquid feeding port. An upper baffle is slidably connected to the inner wall of the liquid feeding port. A clamping block extending out of the upper baffle is slidably connected inside the upper baffle. A connecting frame is fixedly connected to the top end of the clamping block. A first through hole is provided at the top end of the upper baffle, and a second through hole is provided on the outer wall of the clamping block.

[0013] As a further solution of the present invention: Teeth are provided on the outer wall of the tooth column, and the teeth are meshed with the first straight gear. The outer wall of the shielding column is in fit with the inner wall of the connecting groove. The outer diameter of the connecting column is smaller than the outer diameter of the shielding column.

[0014] As a further solution of the present invention: Square grooves are provided inside the connecting column and the shielding column, and the inner walls of the square grooves are in fit with the outer walls of the square guide sleeves.

[0015] As a further solution of the present invention: The inner wall of the cover body fits with the top outer wall of the solid feed port. One outer wall of the fixing block fits with the inner wall of the fixing groove. A slope is provided at the top end of the fixing block. The bottom end of the extrusion block contacts the slope. A first threaded hole is provided at the top end of the extrusion block, and the first threaded hole matches the first threaded rod.

[0016] As a further solution of the present invention: Tooth grooves are provided on the outer wall of the pressing frame, and the tooth grooves mesh with the second spur gear. The pressing frame is in an L shape.

[0017] As a further solution of the present invention: The outer wall of the upper baffle fits with the inner wall of the liquid feed port. The inner wall of the card slot fits with one outer wall of the card block.

[0018] As a further solution of the present invention: A second threaded hole is provided at the top end of the lower baffle, and the second threaded hole matches the second threaded rod. The first bevel gear meshes with the second bevel gear. A third threaded hole is provided on the outer wall of the pressing plate, and the third threaded hole matches the third threaded rod.

[0019] As a further solution of the present invention: A T-shaped vertical rod is fixedly connected to the bottom end of the inner wall of the liquid feed port. The vertical rod passes through the lower baffle. A cross bar is fixedly connected to one outer wall of the liquid feed port, and the cross bar passes through the pressing plate.

[0020] Application method of the activated biochar composite gel material prepared by the preparation method of the activated biochar composite gel material in the treatment of antibiotic wastewater, using static adsorption or dynamic adsorption methods to treat antibiotic wastewater.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention uses biomass solid waste as raw material, realizing the resource utilization of waste and reducing the preparation cost. The activated biochar composite gel material prepared by the present invention has excellent antibiotic adsorption performance, fast adsorption rate and good reusability.

[0022] 2. The present invention has specifically developed a reaction device for the preparation process. The reaction device is provided with a grinding mechanism. The hydraulic cylinder operates to drive the connecting seat to move downward, driving the rotating seat, connecting column and shielding column to move synchronously. The motor operates to drive the first grinding frame to rotate. The first grinding frame moves downward and rotates, thereby grinding the materials in the grinding chamber. The ground materials fall into the stirring chamber through the gap between the connecting groove and the connecting column. At the same time, the stirring shaft rotates to fully stir and mix the materials, facilitating the grinding and stirring operations of the materials added into the reaction kettle.

[0023] By setting up a solid feeding mechanism and a liquid feeding mechanism, when the cover body is opened, the rotating plate rotates to close the exhaust pipe, and the gas in the reaction kettle is discharged through the solid feeding port, so that nitrogen gas is continuously discharged in the reaction kettle during the addition of solids, thus preventing external air from entering the reaction kettle through the solid feeding port; when adding liquid, the air in the liquid feeding port is discharged in advance to prevent external air from entering the reaction kettle through the feeding port during the addition of materials; The reaction device has functions of nitrogen gas protection, grinding, water washing and drying, temperature control for heating and heat preservation, and stirring to prevent adhesion. The basic preparation function of the activated biochar composite gel material can be realized by one device, which can effectively reduce the material transfer link, reduce loss and improve production efficiency.

[0024] 3. The antibiotic wastewater treatment method provided by the present invention is simple to operate, low in cost, and easy to be popularized and applied industrially. Brief Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of the reaction device described in the present invention; Figure 2 It is a schematic diagram of the internal structure of the reaction kettle of the reaction device described in the present invention; Figure 3 It is a schematic diagram of the internal structure of the solid feeding port of the reaction device described in the present invention; Figure 4 It is a schematic diagram of the internal structure of the cover body of the reaction device described in the present invention; Figure 5 It is a schematic diagram of the internal structure of the liquid feeding port of the reaction device described in the present invention; Figure 6 It is a schematic diagram of the internal structure of the upper baffle of the reaction device described in the present invention.

[0026] In the figure: 1, reaction kettle; 2, discharge port; 3, valve; 4, heat-conducting oil coil pipe; 5, oil outlet; 6, oil inlet; 7, grinding mechanism; 701, grinding bin; 702, connecting groove; 703, stirring bin; 704, mounting rack; 705, hydraulic cylinder; 706, connecting seat; 707, tooth column; 708, motor; 709, first straight gear; 710, rotating seat; 711, connecting column; 712, shielding column; 713, mounting plate; 714, stirring shaft; 715, square guide sleeve; 716, first grinding rack; 717, second grinding rack; 718, high-temperature electric heating device; 719, conical filter screen; 720, water washing and drying bin; 721, switching valve; 8, solid feeding mechanism; 801, solid feeding port; 802, cover body; 803, fixing groove; 804, fixing block; 805, first spring; 806, extrusion block; 807, first threaded rod; 808, rotating block; 809, rotating plate; 810, connecting shaft; 811, second straight gear; 812, pressing frame; 813, second spring; 9, liquid feeding mechanism; 901, liquid feeding port; 902, liquid inlet pipe; 903, lower baffle; 904, second threaded rod; 905, first bevel gear; 906, second bevel gear; 907, third threaded rod; 908, rotating column; 909, clamping groove; 910, upper baffle; 911, clamping block; 912, connecting frame; 913, pressing plate; 914, first through hole; 915, second through hole; 10, air inlet pipe; 11, exhaust pipe; 12, vertical rod; 13, cross bar. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0028] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following describes the embodiments according to the overall structure of the present invention. Embodiment 1

[0029] A preparation method of an activated biochar composite gel material, comprising the following steps: S1: Preparation of activated biochar: Crush corn straw to a particle size less than 5 mm and dry it to a constant weight. Place the dried corn straw in a reaction device and heat it to 500 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, hold for 1 h, and then naturally cool to room temperature to obtain biochar. Mix the biochar and KOH in a mass ratio of 1:2 and grind them evenly. Heat the evenly mixed material to 700 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and hold for 1 h; then cool it to 500 °C at a cooling rate of 5 °C / min and then naturally cool to room temperature. Add the pyrolyzed material to a 1 mol / L HCl solution with the same molar amount as KOH, stir for 1 h, then wash it with deionized water until neutral, and dry it to a constant weight to obtain activated biochar.

[0030] S2: Preparation of activated biochar composite gel material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 3%. Add the above sodium alginate aqueous solution to the activated biochar prepared in step S1 at a mass fraction of 10%, stir and heat to 60 °C, and hold for 30 min. Continuously stir the above mixed solution at a speed of 1500 rpm for 24 h. Slowly drop the stirred mixed solution into a 3% CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water, refrigerate and reserve them to obtain the activated biochar composite gel material.

[0031] Please refer to Figures 1 to 6 In the embodiment of the present invention, the reaction device includes a reaction kettle 1. An outlet 2 is provided at the bottom end of the reaction kettle 1. A valve 3 is installed on the outer wall of the outlet 2. A heat-conducting oil coil 4 is installed on the outer wall of the reaction kettle 1. An oil outlet 5 and an oil inlet 6 are respectively provided at both ends of the heat-conducting oil coil 4. An inlet pipe 10 and an exhaust pipe 11 are respectively connected to both sides of the outer wall of the reaction kettle 1. Materials enter the reaction kettle 1 and are ground and stirred through a grinding mechanism 7. Solid materials enter the reaction kettle 1 through a solid feeding mechanism 8, and liquid materials enter the reaction kettle 1 through a liquid feeding mechanism 9.

[0032] The materials in the reaction kettle 1 are discharged through the outlet 2. The heat-conducting oil coil 4 is used for circulating and uniformly heating and heat preservation operation of the reaction kettle 1. Nitrogen continuously enters the reaction kettle 1 through the inlet pipe 10, and the gas in the reaction kettle 1 is discharged through the exhaust pipe 11. It should be noted that one end of the inlet pipe 10 is connected to a nitrogen storage device.

[0033] Please pay special attention to Figures 1 to 2 The grinding mechanism 7 includes a grinding chamber 701, and the grinding chamber 701 is opened inside the reaction kettle 1; a connection groove 702 is opened at the bottom end of the grinding chamber 701, and a water washing and drying chamber 720 and a stirring chamber 703 are sequentially arranged at the bottom end of the connection groove 702. The top end of the reaction kettle 1 is fixedly connected with a mounting frame 704. A hydraulic cylinder 705 is installed at the top end of the mounting frame 704. The output end of the hydraulic cylinder 705 is connected with a connection seat 706. The bottom end of the connection seat 706 is rotatably connected with a tooth column 707. A motor 708 is installed below the mounting frame 704 at the top end of the reaction kettle 1. The output end of the motor 708 is connected with a first spur gear 709. The first spur gear 709 is in contact with the tooth column 707. The bottom end of the tooth column 707 is fixedly connected with a rotating seat 710 located inside the grinding chamber 701. The bottom end of the rotating seat 710 is fixedly connected with a connecting column 711. The bottom end of the connecting column 711 is fixedly connected with a shielding column 712. A square guide sleeve 715 is fixedly connected below the shielding column 712. The outer wall of the rotating seat 710 is fixedly connected with a first grinding frame 716. The inner wall bottom end of the grinding chamber 701 is fixedly connected with a second grinding frame 717; a high-temperature electric heating device 718 is arranged in the grinding chamber 701 below the first grinding frame 716 and in the rotating seat 710 above the second grinding frame 717. The high-temperature electric heating device 718 is an annular electric heating rod or an electric heating ceramic plate.

[0034] The lower part of the water washing and drying chamber 720 is in the shape of an inverted frustum with a large top and a small bottom. One or more switching valves 721 are arranged on the circular bottom surface of the water washing and drying chamber 720; the square guide sleeve 715 extends downward into the water washing and drying chamber 720 and the outer wall of it located inside the water washing and drying chamber 720 is connected with a conical filter screen 719.

[0035] The inner wall of the stirring bin 703 is fixedly connected with a mounting plate 713. A stirring shaft 714 is rotatably connected inside the mounting plate 713. The stirring shaft 714 includes a rotating shaft portion, a cross bar portion and a wall scraping rod. The rotating shaft portion is connected to the wall scraping rod through the cross bar portion. The wall scraping rod is in contact with the inner wall of the stirring bin 703. The upper end of the rotating shaft portion extends upward and enters the water washing and drying bin 720 and then slides into the square guide sleeve 715. The cross section of the inserted section of the rotating shaft portion and the square guide sleeve 715 is square.

[0036] In this embodiment: The crushed and dried agricultural solid wastes such as waste straw are put into the reaction kettle 1. At this time, the shielding column 712 shields and closes the connecting groove 702. The high-temperature electric heating device 718 is started. The materials are pyrolyzed at high temperature for the first time in the grinding bin 701 to generate biochar, and then KOH is added for mixing and grinding. At this time, the hydraulic cylinder 705 is started. The operation of the hydraulic cylinder 705 drives the connecting seat 706 to move downward. The displacement of the connecting seat 706 drives the tooth column 707 to displace. The displacement of the tooth column 707 drives the rotating seat 710, the connecting column 711 and the shielding column 712 to move synchronously, so that the shielding column 712 is displaced below the connecting groove 702. At this time, the square guide sleeve 715 drives the conical filter screen 719 to move downward synchronously and makes the conical filter screen 719 close to the bottom of the water washing and drying bin 720. The outer circumference of the conical filter screen 719 is in close contact with the conical peripheral wall of the water washing and drying bin 720. The switching valve 721 is in a closed state.

[0037] Start the motor 708. The operation of the motor 708 drives the first spur gear 709 to rotate. The rotation of the first spur gear 709 drives the tooth column 707 to rotate. The rotation of the tooth column 707 drives the rotating seat 710 to rotate. The rotation of the rotating seat 710 drives the first grinding frame 716 to rotate. The first grinding frame 716 moves downward and rotates, thereby simultaneously crushing and grinding the materials in the grinding bin 701. The ground materials fall into the water washing and drying bin 720 through the gap between the connecting groove 702 and the connecting column 711. After the grinding and blanking are completed, the solid materials are completely in the water washing and drying bin 720. After the second high-temperature pyrolysis is completed in the water washing and drying bin 720, it is cooled. After cooling, at this time, the HCl solution can be introduced into the reaction kettle 1 through the liquid feeding mechanism 9. Start the motor 708 to drive the square guide sleeve 715 and the conical filter screen 719 to rotate, and complete the full mixing of solid and liquid; then introduce the cleaning solution into the reaction kettle 1 through the liquid feeding mechanism 9, and continue to stir and mix. After the mixing and cleaning are completed, a negative pressure suction device can be connected to the lowermost end of the discharge port 2. At the same time, open the valve 3 and the switching valve 721. After starting the negative pressure suction device, the cleaning solution in the water washing and drying bin 720 and its dissolved soluble salts and other by-products can be sucked away to achieve solid-liquid separation after cleaning; close the valve 3 and the switching valve 721, and start the high-temperature electric heating device 718 for drying. During drying, the nitrogen entering and leaving the device will take away the moisture generated by drying to obtain activated biochar. At this time, the activated biochar is located above the conical filter screen 719.

[0038] Start the hydraulic cylinder 705. The operation of the hydraulic cylinder 705 drives the square guide sleeve 715 and the conical filter screen 719 to move upward. At the same time, the prepared sodium alginate aqueous solution is introduced into the reaction kettle 1 through the liquid feeding mechanism 9. The sodium alginate aqueous solution washes down the activated biochar on the conical filter screen 719 and enters the stirring bin 703 together; at the same time, start the motor 708. The connecting column 711 and the shielding column 712 rotate to drive the square guide sleeve 715 to rotate. The rotation of the square guide sleeve 715 drives the stirring shaft 714 to rotate. The rotation of the stirring shaft 714 drives the materials in the stirring bin 703 to perform the stirring operation.

[0039] Please refer with emphasis to Figures 3 to 4, the solid feeding mechanism 8 includes a solid feeding port 801. The solid feeding port 801 is fixedly connected to the outer wall of the reaction kettle 1 and is located above the exhaust pipe 11. The top end of the solid feeding port 801 is sleeved with a cover body 802. A fixing groove 803 is formed on the outer wall of one side of the solid feeding port 801. A fixing block 804 extending into the inner cavity of the cover body 802 is slidably connected inside the cover body 802. A first spring 805 is connected between the fixing block 804 and the cover body 802. An extrusion block 806 is slidably connected to the inside of the cover body 802 at the top end of the fixing block 804. A rotating block 808 is rotatably connected to the top end of the cover body 802. A first threaded rod 807 is fixedly connected to the bottom end of the rotating block 808. The first threaded rod 807 extends into the inside of the extrusion block 806. A rotating plate 809 is rotatably connected to the inner wall of the exhaust pipe 11. One end of the rotating plate 809 is fixedly connected to a connecting shaft 810. One end of the connecting shaft 810 is fixedly connected to a second spur gear 811. The second spur gear 811 is rotatably connected inside the solid feeding port 801. A pressing frame 812 is slidably connected to the outer wall of the second spur gear 811 inside the solid feeding port 801. A second spring 813 is connected between the bottom end of the pressing frame 812 and the solid feeding port 801. The pressing frame 812 extends above the solid feeding port 801.

[0040] In this embodiment: When closing the solid feeding port 801, the cover body 802 is sleeved on the top end of the solid feeding port 801. At this time, the fixing block 804 is engaged into the fixing groove 803 under the elastic force of the first spring 805 to fix the cover body 802. When opening the solid feeding port 801, rotate the rotating block 808. The rotation of the rotating block 808 drives the first threaded rod 807 to rotate. The rotation of the first threaded rod 807 drives the extrusion block 806 to displace. The displacement of the extrusion block 806 pushes the fixing block 804 out of the fixing groove 803 to cancel the fixation of the cover body 802.

[0041] When the cover body 802 is closed, the cover body 802 contacts the pressing frame 812, pushing the pressing frame 812 to displace, squeezing the second spring 813. The displacement of the pressing frame 812 drives the second spur gear 811 to rotate. The rotation of the second spur gear 811 drives the connecting shaft 810 to rotate. The rotation of the connecting shaft 810 drives the rotating plate 809 to rotate. The rotation of the rotating plate 809 opens the exhaust pipe 11, enabling the gas in the reaction kettle 1 to be discharged through the exhaust pipe 11. When the cover body 802 is opened, the pressing frame 812 is reset under the elastic force of the second spring 813. The reset of the pressing frame 812 drives the rotating plate 809 to rotate to close the exhaust pipe 11, enabling the gas in the reaction kettle 1 to be discharged through the solid feeding port 801. Thus, during the addition of solids, nitrogen continuously discharges from the reaction kettle 1, facilitating the prevention of external air from entering the reaction kettle 1 through the solid feeding port 801 when adding solids.

[0042] Please refer with emphasis to Figures 5 to 6 In this case, the liquid feeding mechanism 9 includes a liquid feeding port 901 which is arranged above the air inlet pipe 10. The bottom end of the liquid feeding port 901 is fixedly connected with a liquid inlet pipe 902, and the bottom end of the liquid inlet pipe 902 is fixedly connected with the reaction kettle 1. A lower baffle 903 is arranged at the bottom end of the inner wall of the liquid feeding port 901. A second threaded rod 904 penetrating through the lower baffle 903 is rotatably connected inside the liquid feeding port 901. A first bevel gear 905 is fixedly connected to the bottom end of the second threaded rod 904. A second bevel gear 906 is rotatably connected to the outer wall of the first bevel gear 905 inside the liquid feeding port 901. A third threaded rod 907 is fixedly connected to one end of the second bevel gear 906. A rotating column 908 is fixedly connected to one end of the third threaded rod 907. A pressing plate 913 is slidably connected to the outer wall of the third threaded rod 907. A clamping groove 909 is formed on one side of the inner wall of the liquid feeding port 901. An upper baffle 910 is slidably connected to the inner wall of the liquid feeding port 901. A clamping block 911 extending out of the upper baffle 910 is slidably connected inside the upper baffle 910. A connecting frame 912 is fixedly connected to the top end of the clamping block 911. A first through hole 914 is formed at the top end of the upper baffle 910. A second through hole 915 is formed on the outer wall of the clamping block 911.

[0043] In this embodiment, when adding liquid, at this time the lower baffle 903 closes the liquid inlet pipe 902, and the liquid is poured into the liquid feeding port 901. After completion, the upper baffle 910 is moved into the liquid feeding port 901. The air between the upper baffle 910 and the liquid is discharged through the first through hole 914 and the second through hole 915. When the upper baffle 910 moves to the top of the liquid level, the clamping block 911 is pushed to displace, and the clamping block 911 displaces and inserts into the clamping groove 909 to fix the upper baffle 910. At the same time, the first through hole 914 and the second through hole 915 are separated, and the clamping block 911 cuts off the first through hole 914. The displacement of the clamping block 911 drives the connecting frame 912 to displace and fit against the outer wall of the liquid feeding port 901. At this time, the rotating column 908 is rotated. The rotation of the rotating column 908 drives the third threaded rod 907 to rotate. The rotation of the third threaded rod 907 drives the second bevel gear 906 to rotate. The rotation of the second bevel gear 906 drives the first bevel gear 905 to rotate. The rotation of the first bevel gear 905 drives the second threaded rod 904 to rotate. The rotation of the second threaded rod 904 drives the lower baffle 903 to displace to open the liquid inlet pipe 902. The liquid in the liquid feeding port 901 enters the reaction kettle 1 through the liquid inlet pipe 902. At the same time, the rotation of the third threaded rod 907 causes the pressing plate 913 to displace. The displacement of the pressing plate 913 contacts the connecting frame 912 to press the connecting frame 912 to prevent the connecting frame 912 from displacing, thereby strengthening the upper baffle 910 and facilitating the prevention of external air from entering the reaction kettle 1 through the liquid feeding port 901 when adding liquid.

[0044] Please refer to particularly Figures 1 to 2 , the outer wall of the tooth column 707 is provided with teeth, the teeth are meshed with the first spur gear 709, the outer wall of the shielding column 712 is fitted with the inner wall of the connecting groove 702, and the outer wall diameter of the connecting column 711 is smaller than the outer wall diameter of the shielding column 712.

[0045] In this embodiment: when the motor 708 operates to drive the first spur gear 709 to rotate, the first spur gear 709 rotates to drive the tooth column 707 to rotate, the tooth column 707 rotates to drive the rotating seat 710 to rotate, and the rotating seat 710 rotates to drive the first grinding frame 716 to rotate; the ground material falls into the stirring bin 703 through the gap between the connecting groove 702 and the connecting column 711.

[0046] Please refer to particularly Figures 1 to 2 , the inner parts of the connecting column 711 and the shielding column 712 are provided with square grooves, and the inner walls of the square grooves are fitted with the outer walls of the square guide sleeves 715.

[0047] In this embodiment: when the connecting column 711 and the shielding column 712 move in the vertical direction, the square guide sleeve 715 slides in the square groove; the connecting column 711 and the shielding column 712 rotate to drive the square guide sleeve 715 to rotate, and the square guide sleeve 715 rotates to drive the stirring shaft 714 to rotate.

[0048] Please refer to particularly Figures 3 to 4 , the inner wall of the cover body 802 is fitted with the top outer wall of the solid feed inlet 801, one end outer wall of the fixing block 804 is fitted with the inner wall of the fixing groove 803, the top end of the fixing block 804 is provided with an inclined surface, the bottom end of the extrusion block 806 is in contact with the inclined surface, and the top end of the extrusion block 806 is provided with a first threaded hole, and the first threaded hole is matched with the first threaded rod 807.

[0049] In this embodiment: the cover body 802 is sleeved on the top end of the solid feed inlet 801, at this time, the fixing block 804 is clamped into the fixing groove 803 under the elastic force of the first spring 805 to fix the cover body 802; when opening the solid feed inlet 801, rotate the rotating block 808, the rotating block 808 rotates to drive the first threaded rod 807 to rotate, the first threaded rod 807 rotates to drive the extrusion block 806 to displace, and the extrusion block 806 displaces to push the fixing block 804 out of the fixing groove 803 to cancel the fixation of the cover body 802.

[0050] Please refer to particularly Figures 3 to 4 , the outer wall of the pressing frame 812 is provided with tooth grooves, the tooth grooves are meshed with the second spur gear 811, and the shape of the pressing frame 812 is L-shaped.

[0051] In this embodiment: When the cover 802 is closed, the cover 802 contacts the downward pressing frame 812, pushing the downward pressing frame 812 to displace, squeezing the second spring 813. The displacement of the downward pressing frame 812 drives the second spur gear 811 to rotate, the rotation of the second spur gear 811 drives the connecting shaft 810 to rotate, and the rotation of the connecting shaft 810 drives the rotating plate 809 to rotate.

[0052] Please refer particularly to Figures 5 to 6 , the outer wall of the upper baffle 910 fits against the inner wall of the liquid inlet 901, and the inner wall of the card slot 909 fits against the outer wall of one end of the card block 911.

[0053] In this embodiment: Move the upper baffle 910 into the liquid inlet 901. The air between the upper baffle 910 and the liquid is discharged through the first through hole 914 and the second through hole 915. When the upper baffle 910 moves to the top of the liquid level, it pushes the card block 911 to displace, and the displaced card block 911 is inserted into the card slot 909 to fix the upper baffle 910.

[0054] Please refer particularly to Figures 5 to 6 , a second threaded hole is opened at the top end of the lower baffle 903, the second threaded hole matches the second threaded rod 904, the first bevel gear 905 meshes with the second bevel gear 906, and a third threaded hole is opened on the outer wall of the pressing plate 913, and the third threaded hole matches the third threaded rod 907.

[0055] In this embodiment: Rotate the rotating column 908. The rotation of the rotating column 908 drives the third threaded rod 907 to rotate. The rotation of the third threaded rod 907 drives the second bevel gear 906 to rotate. The rotation of the second bevel gear 906 drives the first bevel gear 905 to rotate. The rotation of the first bevel gear 905 drives the second threaded rod 904 to rotate. The rotation of the second threaded rod 904 drives the lower baffle 903 to displace.

[0056] Please refer particularly to Figures 5 to 6 , a T-shaped vertical rod 12 is fixedly connected to the bottom end of the inner wall of the liquid inlet 901. The vertical rod 12 penetrates through the lower baffle 903. A cross rod 13 is fixedly connected to the outer wall of one side of the liquid inlet 901, and the cross rod 13 penetrates through the pressing plate 913.

[0057] In this embodiment: When the lower baffle 903 moves, the lower baffle 903 slides along the outer wall of the vertical rod 12 to limit the moving direction of the lower baffle 903; when the pressing plate 913 moves, the pressing plate 913 slides along the outer wall of the cross rod 13 to limit the moving direction of the pressing plate 913.

[0058] In this embodiment, the crushed and dried biomass solid waste and KOH can be put into the grinding chamber 701 through the solid feed port 801, while the HCl solution, the cleaning solution, and the prepared sodium alginate aqueous solution are all first put into the grinding chamber 701 through the liquid feed port 901, and then enter the water washing and drying chamber 720 and the stirring chamber 703 along the connecting groove 702, so as to realize the feeding of two types of solid and liquid materials. After obtaining the mixed solution by high-speed stirring in the stirring chamber 703, then open the valve 3 on the discharge port 2, and slowly drip the mixed solution into a container filled with CaCl2 solution placed in advance below the discharge port 2 to form gel beads and complete the processes of hardening and cleaning in sequence. Therefore, the reaction device designed for the process of the present invention can almost complete most of the preparation processes of the activated biochar composite gel material, simplify the operation steps and effectively improve the production efficiency. Example 2

[0059] S1: Preparation of activated biochar: Crush the wood chips to a particle size less than 5 mm and dry to constant weight. Put the dried wood chips into the reaction device, heat to 600 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 2 h, and then naturally cool to room temperature to obtain biochar. Mix the biochar and KOH in a mass ratio of 1:3 and grind until uniform. Heat the uniformly mixed material to 800 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 2 h, and the cooling rate is 5 °C / min. Cool to 300 °C and then naturally cool to room temperature. Add the pyrolyzed material to 1 mol / L HCl solution with the same molar amount as KOH, stir for 1 h, then wash with deionized water until neutral, and dry to constant weight to obtain activated biochar.

[0060] S2: Preparation of activated biochar composite gel material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 4%. Add the sodium alginate aqueous solution to the activated biochar prepared in step S1 at a mass fraction of 20%, stir and heat up to 90 °C, and hold for 30 min. Continuously stir the above mixed solution at a speed of 2000 rpm for 48 h. Slowly drip the stirred mixed solution into 4% CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water and store them in the refrigerator for later use to obtain the activated biochar composite gel material.

[0061] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1, and will not be elaborated here. Example 3

[0062] S1: Preparation of activated biochar: Crush peanut shells to a particle size less than 5 mm and dry them to a constant weight. Place the dried peanut shells in a reaction device, heat them to 450 °C at a heating rate of 7 °C / min under a nitrogen atmosphere, hold for 1.5 h, and then naturally cool to room temperature to obtain biochar. Mix the biochar and KOH at a mass ratio of 1:1.5 and grind them until uniform. Heat the uniformly mixed material to 650 °C at a heating rate of 7 °C / min under a nitrogen atmosphere, hold for 1.5 h, with a cooling rate of 5 °C / min, cool to 600 °C, and then naturally cool to room temperature. Add the pyrolyzed material to a 1 mol / L HCl solution with the same molar amount as KOH, stir for 1 h, then wash with deionized water until neutral, and dry to a constant weight to obtain activated biochar.

[0063] S2: Preparation of activated biochar composite gel material: Dissolve sodium alginate in deionized water to prepare a 2.5% SA aqueous solution by mass fraction. Add the activated biochar prepared in step S1 to the sodium alginate aqueous solution at a mass fraction of 15%, stir and heat to 70 °C, and hold for 30 min. Transfer the above mixed solution to a high-speed stirrer and continuously stir at a speed of 1200 rpm for 36 h. Slowly drop the stirred mixed solution into a 2.5% CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water and store them refrigerated for later use to obtain the activated biochar composite gel material.

[0064] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1 and will not be elaborated here. Example 4

[0065] S1: Preparation of activated biochar: Crush wood chips to a particle size less than 5 mm and dry them to a constant weight. Put the dried wood chips into a reaction device, heat them to 600 °C at a heating rate of 8 °C / min under a nitrogen atmosphere, hold for 3 h, and then naturally cool to room temperature to obtain biochar. Mix the biochar and KOH at a mass ratio of 1:6 and grind them until uniform. Heat the uniformly mixed material to 900 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, hold for 4 h; then cool to 400 °C at a cooling rate of 5 °C / min, and then naturally cool to room temperature. Add the pyrolyzed material to a 1 mol / L HCl solution with the same molar amount as KOH, stir for 1 h, then wash with deionized water until neutral, and dry to a constant weight to obtain activated biochar.

[0066] S2: Preparation of Activated Biochar Composite Gel Material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 2%. Add the above sodium alginate aqueous solution to the activated biochar prepared in step S1 at a ratio of 5% by mass fraction, stir and heat up to 50 °C, and keep it for 30 min. Continuously stir the above mixture at a speed of 1000 rpm for 12 h. Slowly drop the stirred mixture into a 2% CaCl2 solution with a volume 5 times that of the mixture to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water, store them in the refrigerator for later use, and obtain the activated biochar composite gel material.

[0067] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1, and will not be elaborated here. Example 5

[0068] S1: Preparation of Activated Biochar: Crush peanut shells to a particle size less than 5 mm and dry them to a constant weight. Place the dried peanut shells in a reaction device, heat them to 400 °C at a heating rate of 2 °C / min under a nitrogen atmosphere, keep it for 5 h, and then naturally cool to room temperature to obtain biochar. Mix the biochar and KOH at a mass ratio of 1:0.5 and grind them until uniform. Heat the uniformly mixed material to 600 °C at a heating rate of 3 °C / min under a nitrogen atmosphere and keep it for 1 h; then cool it to 600 °C at a cooling rate of 5 °C / min and then naturally cool to room temperature. Add the pyrolyzed material to a 1 mol / L HCl solution with the same molar amount as KOH, stir for 1 h, then wash it with deionized water until neutral, and dry it to a constant weight to obtain activated biochar.

[0069] S2: Preparation of Activated Biochar Composite Gel Material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 4%. Add the above sodium alginate aqueous solution to the activated biochar prepared in step S1 at a ratio of 20% by mass fraction, stir and heat up to 90 °C, and keep it for 30 min. Continuously stir the above mixture at a speed of 2000 rpm for 48 h. Slowly drop the stirred mixture into a 4% CaCl2 solution with a volume 5 times that of the mixture to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water, store them in the refrigerator for later use, and obtain the activated biochar composite gel material.

[0070] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1, and will not be elaborated here. Comparative Example 1: Unactivated Biochar Composite Gel Material

[0071] S1: Preparation of biochar: The corn stalks were crushed to a particle size of less than 5 mm and dried to constant weight. The dried corn stalks were placed in a tubular furnace and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, maintained for 1 hour, and then naturally cooled to room temperature to obtain biochar. The biochar was added to a 1 mol / L HCl solution, stirred for 1 hour, then washed with deionized water until neutral, and dried to constant weight to obtain unactivated biochar.

[0072] S2: Preparation of biochar composite gel material: Sodium alginate was dissolved in deionized water to prepare a 3% sodium alginate aqueous solution. Unactivated biochar was added to the sodium alginate aqueous solution at a mass fraction of 10%, stirred and heated to 60°C for 30 minutes. The mixture was transferred to a high-speed stirrer and stirred at 1500 rpm for 24 hours. The stirred mixture was slowly dripped into a 3% CaCl2 solution with a volume of 5 times to form gel balls. The gel balls were allowed to harden in the CaCl2 solution for 24 hours, then cleaned with deionized water and refrigerated for later use to obtain an unactivated biochar composite gel material. Comparative Example 2: Preparation of pure sodium alginate gel material without adding activated biochar

[0073] Sodium alginate was dissolved in deionized water to prepare a 3% sodium alginate aqueous solution. The sodium alginate aqueous solution was transferred to a high-speed stirrer and stirred at 1500 rpm for 24 hours. The stirred solution was slowly dripped into a 3% CaCl2 solution with a volume of 5 times to form gel balls. The gel balls were allowed to harden in the CaCl2 solution for 24 hours, then cleaned with deionized water and refrigerated for later use to obtain pure sodium alginate gel material. Comparative Example 3: Preparation of composite gel material with low addition amount of activated biochar

[0074] S1: Preparation of biochar: Step S1 of Example 1.

[0075] S2: Preparation of activated biochar composite gel material: Sodium alginate was dissolved in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 3%. Activated biochar was added to the sodium alginate aqueous solution at a mass fraction of 2%, stirred and heated to 60°C, and maintained for 30 minutes. The above mixture was transferred to a high-speed stirrer and stirred continuously at a speed of 1500 rpm for 24 hours. The stirred mixture was slowly dripped into a 3% CaCl2 solution with a volume of 5 times to form gel balls. The gel balls were allowed to harden in the CaCl2 solution for 24 hours, then washed with deionized water, and refrigerated for use to obtain a composite gel material with too low activated biochar addition.

[0076] The reaction device used to prepare the activated biochar composite gel material is the same as that in Example 1, and will not be described in detail here. Comparative Example 4: Preparation of Composite Gel Material without High-Speed Stirring

[0077] S1: Preparation of Biochar: Step S1 of Example 1.

[0078] S2: Preparation of Activated Biochar Composite Gel Material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 3%. Add activated biochar to the sodium alginate aqueous solution at a mass fraction of 10%, stir and heat up to 60°C, and keep for 30 min. Slowly drop the mixed solution into a 3% CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water and store them in the refrigerator for later use to obtain a composite gel material without high-speed stirring.

[0079] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1, which will not be elaborated here.

[0080] Comparative Example 5: Preparation of Composite Gel Material with a Low CaCl2 Concentration

[0081] S1: Preparation of Biochar: Step S1 of Example 1.

[0082] S2. Preparation of Activated Biochar Composite Gel Material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 3%. Add activated biochar to the sodium alginate aqueous solution at a mass fraction of 10%, stir and heat up to 60°C, and keep for 30 min. Transfer the above mixed solution to a high-speed stirrer and continuously stir at a speed of 1500 rpm for 24 h. Slowly drop the stirred mixed solution into a 1% CaCl2 solution with a volume 5 times that of the mixed solution to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water and store them in the refrigerator for later use to obtain a composite gel material with an excessively low CaCl2 concentration.

[0083] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1, which will not be elaborated here. Comparative Example 6: The Proportion of KOH Exceeds the Protection Upper Limit

[0084] S1: Preparation of activated biochar: The wood chips are crushed to a particle size less than 5 mm and dried to a constant weight. The dried wood chips are put into a reaction device and heated to 600 °C at a heating rate of 8 °C / min under a nitrogen atmosphere, held for 3 h, and then naturally cooled to room temperature to obtain biochar. The biochar and KOH are mixed at a mass ratio of 1:8 and ground until homogeneous. The uniformly mixed material is heated to 900 °C at a heating rate of 10 °C / min under a nitrogen atmosphere and held for 4 h; then, it is cooled to 400 °C at a cooling rate of 5 °C / min and then naturally cooled to room temperature. The pyrolyzed material is added to a 1 mol / L HCl solution with the same molar amount as KOH, stirred for 1 h, then washed with deionized water until neutral, and dried to a constant weight to obtain activated biochar.

[0085] S2: Preparation of activated biochar composite gel material: Sodium alginate is dissolved in deionized water to prepare a 2% sodium alginate aqueous solution by mass fraction. The above sodium alginate aqueous solution is added to the activated biochar prepared in step S1 at a mass fraction of 5%, stirred and heated to 50 °C, and held for 30 min. The above mixture is continuously stirred at a speed of 1000 rpm for 12 h. The stirred mixture is slowly dropped into a 2% CaCl2 solution with a volume 5 times that of the mixture to form gel beads. The gel beads are hardened in the CaCl2 solution for 24 h, then washed clean with deionized water and stored refrigerated for later use to obtain the activated biochar composite gel material.

[0086] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1 and will not be elaborated here. Comparative Example 7: The addition amount of biochar exceeds the upper limit of protection

[0087] S1: Preparation of activated biochar: The peanut shells are crushed to a particle size less than 5 mm and dried to a constant weight. The dried peanut shells are placed in a reaction device and heated to 500 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, held for 1 h, and then naturally cooled to room temperature to obtain biochar. The biochar and KOH are mixed at a mass ratio of 1:2 and ground until homogeneous. The uniformly mixed material is heated to 700 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and held for 1 h; then, it is cooled to 500 °C at a cooling rate of 5 °C / min and then naturally cooled to room temperature. The pyrolyzed material is added to a 1 mol / L HCl solution with the same molar amount as KOH, stirred for 1 h, then washed with deionized water until neutral, and dried to a constant weight to obtain activated biochar.

[0088] S2: Preparation of Activated Biochar Composite Gel Material: Dissolve sodium alginate in deionized water to prepare a sodium alginate aqueous solution with a mass fraction of 3%. Add the above sodium alginate aqueous solution to the activated biochar prepared in step S1 at a ratio of 25% by mass fraction, stir and heat up to 60 °C, and maintain for 30 min. Continuously stir the above mixture at a speed of 1500 rpm for 24 h. Slowly drop the stirred mixture into a 3% CaCl2 solution with a volume 5 times that of the mixture to form gel beads. Let the gel beads harden in the CaCl2 solution for 24 h, then wash them clean with deionized water and store them in the refrigerator for later use to obtain the activated biochar composite gel material.

[0089] The reaction device used for preparing the activated biochar composite gel material is the same as that in Example 1 and will not be elaborated here. Application Test:

[0090] Compare the application data of the activated biochar composite gel materials in Examples 1 - 5 and Comparative Examples 1 - 7 in the treatment of antibiotic wastewater. In the experiment, tetracycline (TC) was used as the target pollutant to investigate the adsorption performance of different materials for TC. Experimental conditions: Antibiotic wastewater: Initial TC concentration is 50 mg / L, pH = 7.0. Adsorbent dosage: 0.1 g / L. Adsorption time: 24 h. Temperature: 25 °C. Detection method: Use ultraviolet-visible spectrophotometry to measure the TC concentration, and calculate the adsorption capacity (Qe, mg / g) and removal rate (%). The test results are shown in Table 1: Table 1 Application Test Results of Activated Biochar Composite Gel Material in Antibiotic Wastewater Treatment

[0091] It can be seen from the test data in Table 1 that the adsorption capacity of the activated biochar composite gel materials prepared in Examples 1 - 5 for TC is between 185.7 - 210.3 mg / g, the removal rate is 98.2 - 99.6%, and the number of repeated uses is 4 - 6 times. Among them, in Example 4, the KOH ratio is 1:6, and the adsorption capacity reaches 210.3 mg / g; in Example 5, the KOH ratio is 1:0.5, and the number of repeated uses is 6 times. The adsorption capacity of Comparative Examples 1 - 7 is between 12.3 - 168.5 mg / g, the removal rate is 6.2 - 84.3%, and the number of repeated uses is 1 - 4 times.

[0092] The adsorption capacity of Comparative Example 1 (unactivated biochar) was 85.6 mg / g, and the removal rate was 42.8%, indicating that KOH activation treatment plays an important role in improving the adsorption performance. The adsorption capacity of Comparative Example 2 (pure sodium alginate gel) was the lowest, at 12.3 mg / g, indicating that activated biochar is the main adsorption active component. The adsorption capacity of Comparative Example 3 (activated biochar addition amount of 2%) was 102.4 mg / g, which was higher than that of Comparative Example 1 but 96.1 mg / g lower than that of Example 1, showing the influence of the biochar addition amount on the performance. The adsorption capacity of Comparative Example 6 (KOH ratio of 1:8) was 57.2 mg / g higher than that of Comparative Example 1 but 67.5 mg / g lower than that of Example 4, indicating that there is an appropriate range for the KOH ratio.

[0093] In terms of the reuse performance, Examples 1-5 could all maintain effective use for more than 4 times, and Example 5 reached 6 times. The reuse times of Comparative Examples 1, 3, and 4 were 3-4 times, and those of Comparative Examples 2, 5, 6, and 7 were 1-3 times. The test results showed that factors such as the KOH activation ratio, biochar addition amount, stirring conditions, and CaCl2 concentration jointly affect the adsorption performance and stability of the material.

[0094] In summary, the activated biochar composite gel materials prepared in the present invention (Examples 1-5) showed excellent adsorption performance, reuse performance, and mechanical strength in the treatment of antibiotic wastewater. KOH activation, activated biochar addition amount, high-speed stirring, and CaCl2 concentration are the key factors affecting the material performance. Compared with Comparative Examples 1-7, the materials of Examples 1-5 had significant advantages in terms of adsorption capacity, removal rate, reuse times, and mechanical strength, and were suitable for industrial promotion and application.

[0095] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes, should be covered by the protection scope of the present invention.

Claims

1. A preparation method of an activated biochar composite gel material, characterized in that It includes the following steps: S1: Preparation of activated biochar: Crush the biomass solid waste after screening to remove impurities to a particle size less than 5 mm, and dry it to a constant weight; Place the dried biomass raw material in a reaction device for the first high-temperature pyrolysis, and then naturally cool it to room temperature to obtain biochar; Mix the biochar and KOH according to the mass ratio and grind them until uniform; Carry out the second high-temperature pyrolysis on the uniformly mixed material in the reaction device, with a cooling rate of 5 °C / min, cool it to 300 - 600 °C, and then naturally cool it to room temperature; Add 1 mol / L HCl solution with the same molar amount as KOH to the pyrolyzed material, stir for 1 h, then wash it with deionized water until neutral, and dry it to a constant weight to obtain activated biochar; S2: Preparation of activated biochar composite gel material: Dissolve sodium alginate in deionized water to prepare an aqueous sodium alginate solution; Add the above aqueous sodium alginate solution to the activated biochar prepared in step S1 at a ratio of 5% - 20% by mass fraction, stir and heat up to 50 - 90 °C, and keep it for 30 min; Continuously stir the above mixed solution at a speed of 1000 - 2000 rpm for 12 - 48 h; Slowly drop the stirred mixed solution into a CaCl2 solution with a volume 5 times that of it to form gel beads; Let the gel beads harden in the CaCl2 solution for 24 h, and then wash them clean with deionized water to obtain the activated biochar composite gel material.

2. The preparation method of an activated biochar composite gel material according to claim 1, characterized in that The biomass solid waste described in step S1 is any one or a combination of several of straw, wood chips, and fruit shells; The first high-temperature pyrolysis described in step S1 means heating to 400 - 600 °C at a heating rate of 2 - 10 °C / min in a nitrogen atmosphere and keeping it for 1 - 5 h; The mass ratio of the biochar and KOH described in step S1 is (1:0.5) - (1:6); The second high-temperature pyrolysis described in step S1 means heating to 600 - 900 °C at a heating rate of 3 - 10 °C / min in a nitrogen atmosphere and keeping it for 1 - 4 h; The preparation of the aqueous sodium alginate solution described in step S2 is an aqueous sodium alginate solution with a mass fraction of 2% - 4%; The concentration of the CaCl2 solution described in step S2 is 2% - 4% by mass fraction.

3. The preparation method of an activated biochar composite gel material according to claim 1, characterized in that, The reaction device includes a reaction kettle (1), a discharge port (2) is provided at the bottom end of the reaction kettle (1), a valve (3) is installed on the outer wall of the discharge port (2), a heat transfer oil coil (4) is installed on the outer wall of the reaction kettle (1), an oil outlet (5) and an oil inlet (6) are respectively provided at both ends of the heat transfer oil coil (4), an intake pipe (10) and an exhaust pipe (11) are respectively connected to both sides of the outer wall of the reaction kettle (1), materials enter the reaction kettle (1) and are ground and stirred through a grinding mechanism (7), solid materials enter the reaction kettle (1) through a solid feeding mechanism (8), and liquid materials enter the reaction kettle (1) through a liquid feeding mechanism (9); the grinding mechanism (7) includes a grinding chamber (701), and the grinding chamber (701) is opened inside the reaction kettle (1); a connection groove (702) is opened at the bottom end of the grinding chamber (701), and a water washing and drying chamber (720) and a stirring chamber (703) are sequentially arranged at the bottom end of the connection groove (702).

4. The preparation method of the activated biochar composite gel material according to claim 2, wherein, The top of the reactor (1) is fixedly connected with a mounting frame (704). A hydraulic cylinder (705) is installed at the top of the mounting frame (704). The output end of the hydraulic cylinder (705) is connected with a connecting seat (706). The bottom end of the connecting seat (706) is rotatably connected with a tooth column (707). A motor (708) is installed below the mounting frame (704) at the top of the reactor (1). The output end of the motor (708) is connected with a first spur gear (709). The first spur gear (709) is in contact with the tooth column (707). The bottom end of the tooth column (707) is fixedly connected with a rotating seat (710) located inside the grinding chamber (701). The bottom end of the rotating seat (710) is fixedly connected with a connecting column (711). The bottom end of the connecting column (711) is fixedly connected with a shielding column (712). A square guide sleeve (715) is fixedly connected below the shielding column (712). The outer wall of the rotating seat (710) is fixedly connected with a first grinding frame (716). The bottom end of the inner wall of the grinding chamber (701) is fixedly connected with a second grinding frame (717); a high-temperature electric heating device (718) is arranged in the grinding chamber (701) below the first grinding frame (716) and in the rotating seat (710) above the second grinding frame (717). The high-temperature electric heating device (718) is an annular electric heating rod or an electric heating ceramic plate; the lower part of the water washing and drying bin (720) is in the shape of an inverted frustum with a larger top and a smaller bottom. One or more switching valves (721) are arranged on the circular bottom surface of the water washing and drying bin (720); the square guide sleeve (715) extends downward into the water washing and drying bin (720), and a conical filter screen (719) is connected to the outer wall of the square guide sleeve (715) located inside the water washing and drying bin (720); the inner wall of the stirring bin (703) is fixedly connected with a mounting plate (713). A stirring shaft (714) is rotatably connected inside the mounting plate (713). The stirring shaft (714) includes a rotating shaft part, a cross bar part and a wall scraping rod. The rotating shaft part is connected with the wall scraping rod through the cross bar part. The wall scraping rod is in fit with the inner wall of the stirring bin (703); the upper end of the rotating shaft part extends upward and enters the water washing and drying bin (720) and then is slidably inserted into the square guide sleeve (715). The cross-sectional shape of the inserted section of the rotating shaft part and the square guide sleeve (715) is square.

5. The preparation method of the activated biochar composite gel material according to claim 4, characterized in that, The solid feeding mechanism (8) includes a solid feeding port (801). The solid feeding port (801) is fixedly connected to the outer wall of the reaction kettle (1) and is located above the exhaust pipe (11). A cover body (802) is sleeved on the top end of the solid feeding port (801). A fixing groove (803) is formed on the outer wall of one side of the solid feeding port (801). A fixing block (804) extending into the inner cavity of the cover body (802) is slidably connected inside the cover body (802). A first spring (805) is connected between the fixing block (804) and the cover body (802). An extrusion block (806) is slidably connected to the top end of the fixing block (804) inside the cover body (802). A rotating block (808) is rotatably connected to the top end of the cover body (802). A first threaded rod (807) is fixedly connected to the bottom end of the rotating block (808). The first threaded rod (807) extends into the extrusion block (806). A rotating plate (809) is rotatably connected to the inner wall of the exhaust pipe (11). One end of the rotating plate (809) is fixedly connected to a connecting shaft (810). One end of the connecting shaft (810) is fixedly connected to a second spur gear (811). The second spur gear (811) is rotatably connected inside the solid feeding port (801). A pressing frame (812) is slidably connected to the outer wall of the second spur gear (811) inside the solid feeding port (801). A second spring (813) is connected between the bottom end of the pressing frame (812) and the solid feeding port (801). The pressing frame (812) extends above the solid feeding port (801).

6. The preparation method of the activated biochar composite gel material according to claim 5, characterized in that, The liquid feeding mechanism (9) includes a liquid feeding port (901), the liquid feeding port (901) is arranged above the air inlet pipe (10), the bottom end of the liquid feeding port (901) is fixedly connected with a liquid inlet pipe (902), the bottom end of the liquid inlet pipe (902) is fixedly connected with the reaction kettle (1), a lower baffle (903) is arranged at the bottom end of the inner wall of the liquid feeding port (901), a second threaded rod (904) penetrating through the lower baffle (903) is rotatably connected inside the liquid feeding port (901), a first bevel gear (905) is fixedly connected to the bottom end of the second threaded rod (904), a second bevel gear (906) is rotatably connected to the outer wall of the first bevel gear (905) inside the liquid feeding port (901), a third threaded rod (907) is fixedly connected to one end of the second bevel gear (906), a rotating column (908) is fixedly connected to one end of the third threaded rod (907), a pressing plate (913) is slidably connected to the outer wall of the third threaded rod (907), a clamping groove (909) is formed on one side of the inner wall of the liquid feeding port (901), an upper baffle (910) is slidably connected to the inner wall of the liquid feeding port (901), a clamping block (911) extending out of the upper baffle (910) is slidably connected inside the upper baffle (910), a connecting frame (912) is fixedly connected to the top end of the clamping block (911), a first through hole (914) is formed at the top end of the upper baffle (910), and a second through hole (915) is formed on the outer wall of the clamping block (911).

7. The preparation method of the activated biochar composite gel material according to claim 4, characterized in that, Gear teeth are formed on the outer wall of the tooth column (707), the gear teeth are meshed with the first spur gear (709), the outer wall of the shielding column (712) is in fit with the inner wall of the connecting groove (702), and the outer wall diameter of the connecting column (711) is smaller than the outer wall diameter of the shielding column (712); a square groove is formed inside the connecting column (711) and the shielding column (712), and the outer wall of the square groove is in fit with the outer wall of the square guide sleeve (715).

8. The preparation method of the activated biochar composite gel material according to claim 5, characterized in that, The inner wall of the cover body (802) is in fit with the top outer wall of the solid feeding port (801), the outer wall of one end of the fixing block (804) is in fit with the inner wall of the fixing groove (803), a slope is arranged at the top end of the fixing block (804), the bottom end of the extrusion block (806) is in contact with the slope, a first threaded hole is formed at the top end of the extrusion block (806), and the first threaded hole is matched with the first threaded rod (807); a tooth groove is formed on the outer wall of the lower pressing frame (812), the tooth groove is meshed with the second spur gear (811), and the lower pressing frame (812) is in an L shape.

9. The preparation method of the activated biochar composite gel material according to claim 6, wherein The outer wall of the upper baffle (910) fits against the inner wall of the liquid feed port (901), and the inner wall of the card slot (909) fits against the outer wall of one end of the card block (911); a second threaded hole is opened at the top end of the lower baffle (903), the second threaded hole is matched with the second threaded rod (904), the first bevel gear (905) meshes with the second bevel gear (906), and a third threaded hole is opened on the outer wall of the pressing plate (913), the third threaded hole is matched with the third threaded rod (907); a T-shaped vertical rod (12) is fixedly connected to the bottom end of the inner wall of the liquid feed port (901), the vertical rod (12) penetrates through the lower baffle (903), and a cross bar (13) is fixedly connected to the outer wall of one side of the liquid feed port (901), the cross bar (13) penetrates through the pressing plate (913).

10. Method for applying the activated biochar composite gel material prepared by the preparation method of the activated biochar composite gel material according to any one of claims 1-9 in the treatment of antibiotic wastewater, characterized in that: The antibiotic wastewater is treated by static adsorption or dynamic adsorption method.

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