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CN-121669176-B - Directional activation modified biochar based on green bristlegrass silicon-rich-vascular bundle structure, preparation method and application thereof

CN121669176BCN 121669176 BCN121669176 BCN 121669176BCN-121669176-B

Abstract

The invention belongs to the technical field of advanced treatment of environmental functional materials and antibiotic wastewater, and particularly relates to directional activation modified biochar based on a green bristlegrass silicon-rich-vascular bundle structure, a preparation method and application thereof; the preparation method comprises the steps of cleaning, drying, crushing and sieving green bristlegrass, immersing green bristlegrass powder in KOH solution to initiate preactivation, drying after the immersion is finished, pyrolyzing the immersed sample in inert atmosphere, and finally sequentially carrying out acid washing, water washing, drying, crushing and sieving on the pyrolyzed sample to obtain the directional activated modified biochar. The preparation method is simple in preparation process and low in cost, and the prepared material has a high specific area, is mainly mesoporous, has the surface rich in oxygen-containing functional groups, can be used as a high-selectivity and high-capacity tetracycline adsorption material, and can keep stable adsorption performance in a wide pH range. The invention realizes the double targets of waste recycling and antibiotic deep purification, and has extremely strong industrialization value and application prospect.

Inventors

  • BAI JIANFENG
  • FANG XINYUAN
  • WANG ZHI
  • GU WEIHUA
  • WANG XIAONUAN
  • JIANG YANXI
  • PENG SHENGJUAN
  • ZHAO JING

Assignees

  • 上海第二工业大学

Dates

Publication Date
20260512
Application Date
20260211

Claims (10)

  1. 1. The application of the oriented activated modified biochar based on the green bristlegrass silicon-vascular bundle structure in the water body tetracycline adsorption removal is characterized in that the initial pH value of an adsorption system is 3-9, and the preparation method of the oriented activated modified biochar based on the green bristlegrass silicon-vascular bundle structure comprises the following steps: (1) Cleaning and drying green bristlegrass, pulverizing and sieving to obtain green bristlegrass powder; (2) Soaking green bristlegrass powder in KOH solution with the concentration of 1.5-2.5 mol/L for 20-28 h to enable KOH to fully permeate into the green bristlegrass vascular bundle channels and silicate gaps to initiate preactivation; (3) Pyrolyzing the immersed sample obtained in the step (2) at 550-650 ℃ in an inert atmosphere, decarboxylating and crosslinking the KOH and cellulose in the green bristlegrass in the pyrolysis process, and simultaneously carrying out a collaborative etching reaction with a silicic acid body to directionally form a lamellar mesoporous-microporous composite structure; (4) Firstly, pickling to remove potassium salt and silicate residues in a pyrolyzed sample, then, washing with deionized water, finally, drying, crushing and sieving to obtain the oxygen-containing functional group directional activation modified biochar with the surface rich in hydroxyl groups, carboxyl groups and ether bonds based on the setaria silicon-rich-vascular bundle structure, wherein: In the step (3), the temperature is increased to the pyrolysis temperature at the temperature rising rate of 8-12 ℃ per minute, and the pyrolysis time is 1-4 h.
  2. 2. The use according to claim 1, wherein in step (1), the particles are crushed to a particle size of 0.2-1.0 mm and sieved with a 50-mesh sieve.
  3. 3. The use according to claim 1, wherein in step (2) the drying temperature is 75-85 ℃ and the drying time is 20-30 hours.
  4. 4. The use according to claim 1, wherein in step (3), the inert atmosphere is nitrogen or argon at a flow rate of 0.2 to 1.0L/min.
  5. 5. The use according to claim 1, wherein in step (3), the pyrolysis temperature is 580-620 ℃ and the pyrolysis time is 1.5-2.5 h.
  6. 6. The method according to claim 1, wherein in the step (4), 0.5-2mol/L hydrochloric acid or sulfuric acid is used for pickling, and deionized water is used for washing the sample to neutrality.
  7. 7. The use according to claim 1, wherein the oriented activated modified biochar based on the setaria silicon-rich-vascular bundle structure exhibits an oriented lamellar or layered stacked morphology of the setaria vascular bundle structure, and the pores are distributed in multiple stages and have excellent connectivity.
  8. 8. The application of claim 1, wherein the specific surface area of the directionally activated modified biochar based on the bristlegrass silicon-rich-vascular bundle structure is more than or equal to 500m 2 ·g -1 , the total pore volume is 0.4-1.2 cm 3 ·g -1 , the average pore diameter is 2-6 nm, the average pore diameter is more than or equal to Kong Zhanbi and more than or equal to 60%, the thickness of the slice layer is 5-20 nm, and the interlayer spacing is 3-8 nm.
  9. 9. The use according to claim 1, wherein the body of water comprises pharmaceutical wastewater, aquaculture wastewater, hospital wastewater and tetracycline-contaminated surface water, and the initial concentration of tetracycline is 5-200 mg/L.
  10. 10. The use according to claim 1, wherein the modified biochar is added in an amount of 0.1 to 3.0 g/L.

Description

Directional activation modified biochar based on green bristlegrass silicon-rich-vascular bundle structure, preparation method and application thereof Technical Field The invention belongs to the technical field of advanced treatment of environmental functional materials and antibiotic wastewater, and particularly relates to directional activated modified biochar based on a green bristlegrass silicon-rich-vascular bundle structure, a preparation method and application thereof. Background Tetracycline (TC) is widely applied to the fields of clinical medicine, livestock and poultry cultivation and aquaculture because of remarkable antibacterial effect and low cost. The daily use amount of the tetracycline antibiotics in China is more than 30% of the total use amount of the antibiotics, and due to the poor biodegradability (half-life period of months to years), a large amount of non-metabolized tetracyclines enter the water environment through the ways of wastewater discharge, fecal returning and the like, so that the tetracyclines become one of the antibiotics with highest detection frequency and maximum residual concentration in the water. The tetracycline residue not only can destroy the microbial community structure of the water body, but also can induce the generation and transmission of drug-resistant genes, and threatens the health of human bodies through food chain enrichment, so that the tetracycline residue becomes a serious environmental and public health problem to be solved urgently. At present, the water body tetracycline removal technology mainly comprises an advanced oxidation method, a membrane separation technology, a microbial degradation method, an adsorption method and the like, but has obvious defects: ① Advanced Oxidation (AOPs) requires consuming a large amount of oxidant (such as ozone and hydrogen peroxide) or relying on auxiliary energy such as ultraviolet light, ultrasound and the like, has extremely high energy consumption and running cost, is easy to produce intermediate products with unknown toxicity, and has secondary pollution risk; ② The membrane separation technology has the advantages that the investment cost of the membrane component is high, membrane pollution is easy to occur in the operation process, frequent cleaning and maintenance are needed, and the treatment difficulty of the concentrated solution is high, so that the concentrated solution is difficult to apply in a large scale; ③ Microbial degradation, namely, a long degradation period (usually more than 7 days), sensitivity to environmental conditions (pH, temperature and dissolved oxygen) and extremely low treatment efficiency on high-concentration tetracycline wastewater (> 100 mg/L); ④ The adsorption method is a technology with the most application prospect due to simple operation, lower cost and no secondary pollution, but the existing adsorption material has the core bottleneck that the commercial activated carbon has limited adsorption capacity (saturated adsorption capacity of 80-150 mg.g -1) and difficult regeneration, the conventional biochar has low specific surface area (< 300 m 2·g-1), undeveloped pore structure and few surface active functional groups, and the adsorption capacity to tetracycline is generally lower than 100 mg.g -1, so that the requirement of advanced treatment is difficult to meet. Further analysis shows that the existing biochar preparation technology has two key defects that firstly, a directional activation scheme is not designed aiming at inherent structural characteristics of biomass, a general activation process is blindly adopted, the structural potential of the biomass cannot be fully exerted, and secondly, the deep research on the synergistic action mechanism of biomass components and an activating agent is lacking, so that the construction efficiency of a pore structure and an active site is low. The green bristlegrass (SETARIA VIRIDIS) is used as annual weeds of Gramineae, is widely distributed in China, grows rapidly, has annual biomass of 5-8 t/mu, and is agricultural waste biomass with abundant sources and extremely low cost. At present, green bristlegrass is only used for feed, compost or direct incineration, and the unique structural and component advantages of the green bristlegrass are not developed and utilized yet: (1) The vascular bundles are regularly and orderly arranged in the green bristlegrass stalks to form a natural layered micro-channel network, and a natural template is provided for directionally constructing a pore system with excellent connectivity; (2) The silicon-rich characteristic and the high cellulose content are that the green bristlegrass epidermal cells are rich in silicic acid bodies (SiO 2 content is 3-6%), the cellulose content is 35-45%, and the synergistic effect of the silicic acid bodies and the cellulose provides unique conditions for pore expansion and active site introduction in the activation process. However, no research on preparin