Application of iron modified charcoal composite red mud granular material to adsorption of tetracycline in low-temperature water

Abstract

The invention provides an application method for removing tetracycline in low-temperature water by adsorption of an iron modified biochar composite red mud granular material. According to the method, the temperature of a water sample is controlled to be 2-5 DEG C, and the removal rate of tetracycline under each influence factor is explored by changing the pH value of the water sample, the feeding amount of materials and the initial concentration of tetracycline. The material is prepared by the following steps: preparing a red mud granular material from red mud, bentonite and straw powder as raw materials, then preparing turbid liquid from prepared iron-modified biochar and polyvinyl alcohol, impregnating and loading the turbid liquid on the surface of the red mud granular material, thereby obtaining the composite material. The adsorbent provided by the invention has good adsorption performance under a low temperature condition, and is relatively suitable for removing tetracycline in water in a cold region. The application process of the material is relatively simple, and the method has the advantages of solid waste recycling and material reutilization.

Description

Technical Field

[0001] This invention relates to the field of environmental pollution control, specifically to the application of iron-modified biochar composite red mud granular material for adsorbing tetracycline in low-temperature water. This invention also relates to the resource reuse of solid waste, specifically to the resource utilization of industrial by-product red mud and agricultural waste straw, as well as the reuse of the material in adsorbing tetracycline in low-temperature wastewater. Background Technology

[0002] Since their discovery, antibiotics have had a significant impact on human health. If unmetabolized antibiotics enter the environment, they can have potential toxic effects on organisms and humans. Tetracycline antibiotics are among the most commonly used antibiotics globally, widely used in the medical and aquaculture industries. Tetracyclines can enter natural water bodies through human metabolism and animal feces. Antibiotic removal from wastewater in cold regions is a common challenge, primarily because low temperatures limit microbial activity or reduce the reactivity between antibiotics and water treatment agents, leading to decreased removal efficiency.

[0003] While removing tetracycline from low-temperature wastewater, it is important to avoid causing secondary pollution to the environment. Therefore, the selection of materials should be both environmentally friendly and economical.

[0004] In recent years, adsorption has been recognized as a key technology in water treatment due to its numerous advantages, making it suitable for complex aquatic environments, wide pH ranges, and large temperature ranges. Furthermore, adsorption materials are readily available and inexpensive. Currently, research on tetracycline removal primarily focuses on aquatic environments under ambient temperature conditions, while the removal of tetracycline from low-temperature wastewater requires highly efficient methods.

[0005] Red mud and straw, as solid wastes, are produced in huge quantities every year, but their utilization rate is low. These two materials meet the requirements for both environmental protection and economic efficiency. Using red mud and straw as the main raw materials to prepare composite materials for the adsorption and removal of tetracycline in low-temperature water has great application prospects. Summary of the Invention

[0006] To address the problem of tetracycline removal in low-temperature water, this invention provides an application method for iron-modified biochar composite red mud granular material. This material, acting as an adsorbent, leverages the advantages of electrostatic adsorption to achieve efficient removal of tetracycline from water under low-temperature conditions.

[0007] The technical solution of the present invention is as follows:

[0008] This invention provides a method for preparing iron-modified biochar composite red mud granular materials, comprising the following steps:

[0009] (1) Preparation of red mud granules: Red mud, bentonite and straw powder are mixed in proportion, the mixture is ground in a ball mill, then granulated and calcined in a muffle furnace to obtain red mud granules.

[0010] (2) Preparation of pre-made biochar: The collected straw is pyrolyzed and then ground to obtain pre-made biochar.

[0011] (3) Preparation of iron-modified biochar: The biochar prepared in step (2) is treated with alkali to remove its ash content, and then modified with FeCl3 to obtain iron-modified biochar.

[0012] (4) The iron-modified biochar obtained in step (3) is dissolved in polyvinyl alcohol and impregnated on the red mud particles in step (1) to obtain iron-modified biochar composite red mud particles.

[0013] In one specific embodiment, in step (1), the three components are configured in a mass ratio of 4:1:1, the ball milling time is controlled at 2 hours, the rotation speed is controlled at 150 rpm / h, the calcination temperature is 1150°C, the heating rate is controlled at 5°C / min, and the holding time is 15 min.

[0014] In one specific embodiment, in step (2), the pyrolysis temperature is 600℃ and the heating rate is 5℃ / min.

[0015] In one specific embodiment, in step (3), the alkaline treatment uses a 3 mol / L KOH solution, and the temperature is controlled at 60℃~70℃ while stirring at 150 rpm for 1 h. Then, the mixture is washed with water and dried to prepare alkaline biochar. For iron modification, the FeCl3 solution concentration is 0.8 g / L. The pH value needs to be adjusted to 10, the temperature is 30℃, and the mixture is stirred at 150 rpm for 2 h. The pH value is then adjusted to 10 again, and the mixture is allowed to stand at 70℃ for 30 minutes. After washing with water and drying, iron-modified biochar is obtained.

[0016] In one specific embodiment, in step (4), the concentration of the polyvinyl alcohol solution is 2 g / L, and the mass ratio of biochar to red mud particles is 1:10.

[0017] This invention also provides the application of the iron-modified biochar composite red mud granular material in adsorbing tetracycline in water under low-temperature conditions.

[0018] In one specific embodiment, 50 ml of 100 mg / L tetracycline solution was prepared and added to an ice bath beaker. The temperature was controlled at 2-5°C and the pH of the solution was adjusted to 8. 0.1 g of iron-modified biochar composite red mud particles were added to the solution and shaken at 60 r / min for 3 h. The removal rate was 95.5%.

[0019] In one specific embodiment, tetracycline solutions with pH values ​​of 6, 8, and 10, each with a volume of 50 ml and a concentration of 100 mg / L, were prepared. 0.1 g of iron-modified biochar composite red mud particles were added to each solution, and the temperature was controlled at 2-5°C. The mixture was shaken at 60 r / min for 3 h, and the removal rates were 91.05%, 95.5%, and 96.96%, respectively.

[0020] In one specific embodiment, 0.05 g, 0.1 g, 0.15 g, 0.2 g, 0.25 g, and 0.3 g of iron-modified biochar composite red mud particles were weighed and added to a 50 ml solution of 100 mg / L tetracycline. The temperature was controlled at 2-5°C, the pH of the solution was adjusted to 8, and the mixture was shaken at 60 r / min for 3 h. The removal rates were 84.7%, 95.5%, 96.63%, 97.03%, and 98.5%, respectively.

[0021] In one specific embodiment, solutions with tetracycline concentrations of 25 mg / L, 50 mg / L, 75 mg / L, 100 mg / L, and 125 mg / L were prepared in volumes of 50 ml. 0.1 g of iron-modified biochar composite red mud granules were added to each solution. The temperature was controlled at 2–5 °C, the pH of the solution was adjusted to 8, and the solution was shaken at 60 r / min for 3 h. The removal rates were 98.9%, 98.47%, 97.56%, 95.5%, and 93.7%, respectively. Attached Figure Description

[0022] Figure 1 Flowchart of iron-modified biochar composite red mud granular material preparation.

[0023] Figure 2 Photograph of iron-modified biochar composite red mud particle material.

Claims

1. An application of iron-modified biochar composite red mud granules to adsorb tetracycline in low-temperature water, the specific method comprising the following steps: Tetracycline concentration of 100 mg / L is added to an ice bath beaker, with the temperature controlled between 2℃ and 5℃. The iron-modified biochar composite red mud granules are added to the solution and shaken at 60 r / min.

2. The application of the iron-modified biochar composite red mud granular material as described in claim 1 for adsorbing tetracycline in low-temperature water, characterized in that, Under the condition of material vibration reaction for 0.5h to 3h, the removal rate is 80.53% to 95.5%.

3. The application of the iron-modified biochar composite red mud granular material as described in claim 1 for adsorbing tetracycline in low-temperature water, characterized in that... When tetracycline was treated in water samples with a pH value of 6 to 10, the removal rate was 91.05% to 96.96%.

4. The application of the iron-modified biochar composite red mud granular material as described in claim 1 for adsorbing tetracycline in low-temperature water, characterized in that... When the dosage of the composite material is in the range of 1 g / L to 6 g / L, the removal rate is 84.7% to 98.5%.

5. The application of the iron-modified biochar composite red mud granular material as described in claim 1 for adsorbing tetracycline in low-temperature wastewater, characterized in that... When the initial tetracycline concentration is in the range of 0.025 g / L to 0.125 g / L, the removal rate is 93.7% to 98.9%.

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