Modified granular biochar adsorbent as well as preparation and application thereof

Abstract

The invention belongs to the technical field of environmental engineering wastewater treatment, and discloses a modified granular biochar adsorbent as well as preparation and application thereof. The invention relates to a preparation method of a modified granular biochar adsorbent. The preparation method comprises the following steps: 1) cutting agricultural straw waste, and carbonizing; 2) soaking the biomass carbonized material obtained in the step 1) in a metal ion solution, stirring, separating and drying; and 3) mixing the modified charcoal powder material obtained in the step 2) with a polyacrylate emulsion to form a viscous mixture, preparing the mixture into granules, and drying to obtain the modified granular charcoal adsorbent. According to the method disclosed by the invention, resource utilization of agricultural straw wastes is realized, the obtained adsorbent has an excellent adsorption effect on metolachlor, the problems that liquid-solid separation is difficult, a packed column is easy to block and the like in practical application of a powdery adsorbent (micron-sized) are solved, and a simple and efficient method is provided for treating excessive metolachlor in source water.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental engineering wastewater treatment, and in particular relates to a modified granular biochar adsorbent and a preparation and application thereof. Background Art

[0002] Water is one of the most precious resources on earth. It is essential to maintain ecological balance, support economic development and safeguard human life. However, with the continuous development of the global economy and the continuous growth of the population, water pollution is becoming increasingly serious. In addition to traditional pollutants such as heavy metals, organic matter and nutrients, emerging pollutants have gradually become an important part of water pollution. Emerging pollutants refer to toxic and harmful chemicals that have characteristics such as biological toxicity, environmental persistence, difficulty in degradation, and bioaccumulation, are easy to migrate and transform in the environment, and have "three-hazard" risks such as mutagenicity, teratogenicity and carcinogenicity, but have not yet been included in management or the existing management measures are insufficient. In recent years, due to the great harm to the human body, the study of emerging pollutants has received widespread attention from scientists. It is reported that many researchers have detected a certain concentration of emerging pollutants in water sources, which directly threatens the lives and life safety of local residents.

[0003] Isopropylamine is an amide selective herbicide and also belongs to a type of emerging pollutants. The pure product of isopropylamine is a colorless liquid with no odor. It is soluble in most organic solvents and partially soluble in water above 20°C. Isopropylamine can prevent and control annual weeds such as barnyard grass, crabgrass, foxtail grass, teff, and broad-leaved weeds such as purslane, amaranth, and quinoa. It is suitable for weeding in vegetable fields such as potatoes, cruciferous vegetables, watermelons, and solanaceous vegetables. Due to the good effect, low price, and easy use of this type of herbicide, it has been widely promoted and applied in a large area. Studies have shown that isopropylamine is not only highly toxic to aquatic ecosystems, but also has adverse effects on terrestrial ecosystems. Therefore, excessive isopropylamine is bound to cause serious pollution to the water environment, especially the water source water environment. Therefore, the development and design of an isopropylamine adsorption material with good effect, simple preparation, low price and practicality is of great significance to ensure human health.

[0004] Agricultural straw waste is a biomass material produced in the agricultural production process. It is simple and easy to obtain. Except for some agricultural straw waste that is used as feed, compost and biogas fermentation raw materials, most agricultural straw waste materials are discarded, causing environmental pollution and a large amount of resource waste. Biochar is a porous, low-density carbon-containing material produced by the combustion or pyrolysis of biomass under anaerobic or oxygen-limited conditions. It consists of carbonized parts and non-carbonized components. Due to its simple preparation, environmental protection and non-toxicity, biochar has a good development prospect in water treatment. Studies have shown that biochar has a good removal effect on a variety of organic matter including polycyclic aromatic hydrocarbons, phenol, aniline and nitrobenzene. When biochar adsorbs organic matter, it mainly relies on the developed internal pore structure, and adsorbs with the help of π-π bonds or hydrogen bonds between the biochar surface and the adsorbate. However, the particle size of biochar is small, often in the micron level. Even if it has a good removal effect on pollutants, it is difficult to achieve liquid-solid separation and difficult to apply in practice. Especially for the removal of water pollutants in water sources with a large amount of water, biochar with small particle size is even more difficult to apply. Therefore, in order to solve the solid-liquid separation problem, the biochar must be granulated so that it has a larger particle size, higher mechanical strength, less likely to clog the filling column, can be backwashed, and is easy to operate in practical applications. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a modified granular biochar adsorbent.

[0006] Another object of the present invention is to provide a modified granular biochar adsorbent prepared by the above method.

[0007] Another object of the present invention is to provide the use of the modified granular biochar adsorbent in removing isopropylamine from water.

[0008] The purpose of the present invention is achieved through the following solutions:

[0009] A method for preparing a modified granular biochar adsorbent comprises the following steps:

[0010] 1) Cutting agricultural straw waste and carbonizing it to obtain biomass carbonized materials;

[0011] 2) soaking the biomass carbonized material obtained in step 1) in a metal ion solution, stirring, separating, and drying to obtain a modified biochar powder material;

[0012] 3) The modified biochar powder material of step 2) is mixed with the polyacrylate emulsion to form a viscous mixture, and the mixture is prepared into granules, and dried to obtain a modified granular biochar adsorbent.

[0013] Step 1) Before cutting, the straw is washed with water and dried naturally.

[0014] In step 1), the agricultural straw is at least one of rice straw, corn straw, wheat straw and garlic straw.

[0015] In step 1), the length of the cropped agricultural straw waste is 5 to 30 cm, preferably 5 to 20 cm.

[0016] Step 1) The carbonization temperature is 400-800° C., preferably 500-600° C.; the carbonization time is 2.0-6.0 h, preferably 3.0-5.0 h; and the carbonization atmosphere is oxygen.

[0017] Step 2) The metal includes at least one of iron, lanthanum, zirconium and aluminum.

[0018] Step 2) The concentration of metal ions in the metal ion solution is 0.01 to 0.05 mol / L.

[0019] Step 2) The volume mass ratio of the metal ion solution to the biomass carbonized material is 2.0-5.0:1, in units of mL / g.

[0020] The specific operation of the stirring in step 2) is: fully mix the biomass carbonized material and the metal ion solution, stir for 24 to 48 hours, change the water and continue stirring, and repeat this operation for 3 to 5 rounds, wherein the water is replaced with another portion of the metal ion solution with the same concentration and volume.

[0021] Step 2) The separation is to separate the biomass carbonized material from the metal ion solution using a filter cloth.

[0022] The drying temperature in step 2) is 40-70° C., preferably 50-60° C.; the drying time is 12-48 hours, preferably 24 hours.

[0023] Step 3) The mass content of polyacrylate in the polyacrylate emulsion is 41-59%, preferably 50%.

[0024] Step 3) The mass ratio of the modified biochar powder material to the polyacrylate emulsion is 10-100, preferably 20-60.

[0025] The drying temperature in step 3) is 40-70° C., preferably 50-60° C., and the drying time is 12-48 hours, preferably 24 hours.

[0026] The diameter of the modified granular biochar adsorbent in step 3) is 3.0 to 10.0 mm, which is set according to the specific application scenario.

[0027] A modified granular biochar adsorbent prepared by the above method.

[0028] The modified granular biochar adsorbent is used to remove isopropylamine from water.

[0029] The mechanism of the present invention is:

[0030] The present invention first collects agricultural straw waste for resource utilization, carbonizes the agricultural straw waste, and then uses high-valent metal ions to modify its surface to obtain an isopropylamine adsorbent with excellent performance. High-valent metal ions are metals with low cost and strong activity, which can increase the adsorption capacity of biochar. In order to be able to actually apply the adsorbent to the treatment of water source water, obtain a biochar material with a larger particle size, higher mechanical strength, and a filling column that is not easy to be blocked and can be backwashed, the present invention uses a non-toxic and harmless polyacrylate emulsion as a binder to prepare a modified biochar material with a smaller particle size into a granular adsorbent material with high mechanical strength and convenient for practical application. The present invention solves the problems that powdered adsorbents (micrometer level) are difficult to separate liquid and solid in practical applications and that filling columns are easy to be blocked, and provides a simple and efficient method for treating excessive isopropylamine in water source water.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. The present invention can realize the secondary utilization of agricultural straw waste and achieve "waste treatment with waste".

[0033] 2. The preparation method provided by the present invention is simple, and the adsorption capacity of the modified biochar is greatly increased compared with that before modification. This simple and easy method is conducive to large-scale production in practical applications.

[0034] 3. The granular isopropylamine adsorbent prepared by the present invention has good performance, high mechanical strength, and is not easy to be blocked, and is expected to be applied to the treatment of isopropylamine in water sources. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto. If the specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0036] Unless otherwise specified, the reagents used in the examples can be purchased from the market.

[0037] Polyacrylate emulsion building materials are purchased from the market with a solid content of 50%.

[0038] Comparative Example 1

[0039] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for later use, and the dried rice straw waste was cut into strips of 10 cm in length using a guillotine, and then placed in a box furnace for carbonization. The carbonization temperature was set to 500 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonization material. The powdered biochar material was mixed with the polyacrylate emulsion at a mass ratio of 30:1 to form a viscous mixture, and the mixture was prepared into a granular adsorbent with a diameter of 10 mm, which was placed in a 60 ° C oven for drying for 24 h to obtain a granular biochar adsorbent.

[0040] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. Collect effluent samples at different time intervals through an automatic collector, and detect the isopropylamine concentration of the effluent samples. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 32%. After the device treats nearly 10L of raw water, the adsorbent reaches an adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0041] Example 1

[0042] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 10 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 500 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Lanthanum chloride solid was used to prepare 3 parts of 1.0 L lanthanum ion solution with a concentration of 0.02 mol / L, 0.5 kg of biomass carbonized material was weighed and added to 1 part of the metal solution, stirred with a stirrer for 24 hours, and then the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 30:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 10 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0043] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. Collect effluent samples at different time intervals through an automatic collector, and detect the isopropylamine concentration of the effluent samples. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 83%. After the device treats nearly 50L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0044] Example 2

[0045] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 10 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 500 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Lanthanum chloride solid was used to prepare 3 parts of 1.0 L lanthanum ion solution with a concentration of 0.04 mol / L, 0.5 kg of biomass carbonized material was weighed and added to 1 part of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 40:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 5 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0046] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. The effluent samples are collected at different time intervals by an automatic collector, and the isopropylamine concentration of the effluent samples is detected. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 87%. After the device treats nearly 62L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0047] Example 3

[0048] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 5 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 550 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three portions of 1.0 L zirconium ion solution with a concentration of 0.02 mol / L were prepared using zirconium oxychloride solid, 0.5 kg of biomass carbonized material was weighed and added to 1 portion of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 30:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 3 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0049] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. The effluent samples are collected at different time intervals by an automatic collector, and the isopropylamine concentration of the effluent samples is detected. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 72%. After the device treats nearly 45L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0050] Example 4

[0051] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 10 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 600 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three portions of 1.0 L zirconium ion solution with a concentration of 0.04 mol / L were prepared using zirconium oxychloride solid, 0.5 kg of biomass carbonized material was weighed and added to 1 portion of the metal solution, stirred with a stirrer for 24 hours, and then the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 35:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 6 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0052] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. Collect effluent samples at different time intervals through an automatic collector, and detect the isopropylamine concentration of the effluent samples. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 80%. After the device treats nearly 50L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0053] Example 5

[0054] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 15 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 500 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three 1.0 L aluminum ion solutions with a concentration of 0.02 mol / L were prepared using aluminum chloride solid, 0.5 kg of biomass carbonized material was weighed and added to 1 part of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 20:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 10 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0055] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. Collect effluent samples at different time intervals through an automatic collector, and detect the isopropylamine concentration of the effluent samples. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 64%. After the device treats nearly 35 L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0056] Example 6

[0057] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 10 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 600 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three 1.0 L aluminum ion solutions with a concentration of 0.04 mol / L were prepared using aluminum chloride solid, 0.5 kg of biomass carbonized material was weighed and added to 1 part of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 20:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 5 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0058] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. The effluent samples are collected at different time intervals by an automatic collector, and the isopropylamine concentration of the effluent samples is detected. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 76%. After the device treats nearly 45 L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0059] Example 7

[0060] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 5 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 500 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three portions of 1.0 L iron ion solution with a concentration of 0.02 mol / L were prepared using solid ferric chloride, 0.5 kg of biomass carbonized material was weighed and added to 1 portion of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 30:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 8 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0061] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. The effluent samples are collected at different time intervals by an automatic collector, and the isopropylamine concentration of the effluent samples is detected. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 54%. After the device treats nearly 25L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0062] Example 8

[0063] 50 kg of rice straw waste collected from farmland was washed with water, dried naturally for standby use, and the dried rice straw waste was cut into strips of 20 cm in length using a guillotine, and then placed in a box furnace for carbonization, the carbonization temperature was set to 600 ° C, the carbonization time was 3.0 h, and the carbonization atmosphere was oxygen to obtain biomass carbonized material. Three portions of 1.0 L iron ion solution with a concentration of 0.04 mol / L were prepared using solid ferric chloride, 0.5 kg of biomass carbonized material was weighed and added to 1 portion of the metal solution, stirred with a stirrer for 24 hours, and the water was changed and stirred continuously. After repeating this operation for 3 rounds, the carbonized material was separated from the solution using a filter cloth, and the material was dried in an oven at 60 ° C for 24 hours to obtain a modified biochar material. The powdered modified biochar material and the polyacrylate emulsion were mixed in a mass ratio of 35:1 to form a viscous mixture. The mixture was prepared into a granular adsorbent with a diameter of 10 mm, and dried in an oven at 60°C for 24 hours to obtain a granular modified biochar adsorbent.

[0064] Weigh 0.5 kg of the above-prepared granular modified biochar adsorbent into a fixed bed column with a diameter of 8 cm and a height of 50 cm. Use a peristaltic pump to transport the initial isopropylamine concentration of 50 ng / L wastewater into the fixed bed column at a flow rate of 10.0 mL / min for continuous adsorption. The effluent samples are collected at different time intervals by an automatic collector, and the isopropylamine concentration of the effluent samples is detected. In the initial stage of adsorption, the granular modified biochar adsorbent has a good treatment effect on isopropylamine, and the maximum removal rate can reach 65%. After the device treats nearly 30L of raw water, the adsorbent reaches the adsorption saturation state. The adsorption saturated material enriches the pollutants and can be disposed of as solid waste.

[0065] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified granular biochar adsorbent, Features The following steps are involved: 1) Cutting agricultural straw waste and carbonizing it to obtain biomass carbonized materials; 2) soaking the biomass carbonized material obtained in step 1) in a metal ion solution, stirring, separating, and drying to obtain a modified biochar powder material; 3) The modified biochar powder material of step 2) is mixed with the polyacrylate emulsion to form a viscous mixture, and the mixture is prepared into granules, and dried to obtain a modified granular biochar adsorbent.

2. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: Step 1) The agricultural straw is at least one of rice straw, corn straw, wheat straw and garlic straw; Step 1) The length of the cropped agricultural straw waste is 5 to 30 cm.

3. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: Step 1) The carbonization temperature is 400-800° C.; the carbonization time is 2.0-6.0 h; and the carbonization atmosphere is oxygen.

4. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: Step 2) the metal includes at least one of iron, lanthanum, zirconium and aluminum; Step 2) The concentration of metal ions in the metal ion solution is 0.01 to 0.05 mol / L; Step 2) The volume mass ratio of the metal ion solution to the biomass carbonized material is 2.0-5.0:1, in units of mL / g.

5. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: The specific operation of the stirring in step 2) is: fully mix the biomass carbonized material and the metal ion solution, stir for 24 to 48 hours, change the water and continue stirring, and repeat this operation for 3 to 5 rounds, wherein the water is replaced with another portion of the metal ion solution with the same concentration and volume; Step 2) The drying temperature is 40 to 70° C. and the drying time is 12 to 48 hours.

6. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: Step 3) The mass content of polyacrylate in the polyacrylate emulsion is 41-59%; Step 3) The mass ratio of the modified biochar powder material to the polyacrylate emulsion is 10 to 100.

7. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: The drying temperature in step 3) is 40 to 70° C. and the drying time is 12 to 48 hours.

8. The method for preparing the modified granular biochar adsorbent according to claim 1, Features: Step 3) The diameter of the modified granular biochar adsorbent is 3.0 to 10.0 mm.

9. A modified granular biochar adsorbent prepared by the method according to any one of claims 1 to 8.

10. Use of the modified granular biochar adsorbent according to claim 9 in removing isopropylamine from water.