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CN-121974449-A - Bio-based nitrogen-doped carbon material, preparation method thereof and application thereof in treatment of printing and dyeing wastewater

CN121974449ACN 121974449 ACN121974449 ACN 121974449ACN-121974449-A

Abstract

The invention relates to the technical field of wastewater treatment, and particularly discloses a bio-based nitrogen-doped carbon material, a preparation method thereof and application thereof in treating printing and dyeing wastewater. The bio-based nitrogen-doped carbon material is prepared by mixing the carbonized purslane powder and carbon-nitrogen mixed powder prepared by co-carbonizing the purslane powder and silkworm chrysalis shell powder according to a specific proportion. The bio-based nitrogen-doped carbon material is used as a cathode material and applied to the treatment of indigo dyeing wastewater by an electric flocculation and electrochemical oxidation coupling system, so that the carboxyl and hydroxyl groups enriched after the carbonization of purslane can effectively neutralize the raised pH value in the electric flocculation process, the continuous proceeding of flocculation is ensured, proper conditions are provided for oxygen reduction reaction, the occurrence of hydrogen evolution reaction is reduced, the generation amount of OH ‑ is reduced, and the treatment efficiency and stability are cooperatively improved. Meanwhile, the carbon-nitrogen mixed powder has a rich mesoporous structure, and the structure can promote the double-electron oxygen reduction reaction of O 2 , so that the electro-oxidation catalytic efficiency in a wastewater treatment system is remarkably improved.

Inventors

  • ZHANG WEI
  • LU KAILIANG
  • WANG YAN
  • LOU JIANGFEI

Assignees

  • 河北科技大学

Dates

Publication Date
20260505
Application Date
20251212

Claims (10)

  1. 1. The preparation method of the bio-based nitrogen-doped carbon material is characterized by comprising the following steps of: Step a, carbonizing purslane powder at 140-160 ℃ in inert atmosphere to obtain carbonized purslane powder; Step b, uniformly mixing purslane powder and silkworm chrysalis shell powder according to a mass ratio of 5:1-15:1, and carbonizing at 500-600 ℃ in an inert atmosphere to obtain carbon-nitrogen mixed powder; And c, uniformly mixing the purslane carbonized powder and the carbon-nitrogen mixed powder to obtain the bio-based nitrogen-doped carbon material.
  2. 2. The method for preparing the bio-based nitrogen-doped carbon material according to claim 1, wherein in the step a, the carbonization is heated to 140-160 ℃ by adopting a temperature programming mode, and the heating rate is 5-15 ℃ per minute.
  3. 3. The method for preparing a bio-based nitrogen doped carbon material according to claim 1, wherein in the step a, the carbonization time is 20 min-40 min.
  4. 4. The method for preparing the bio-based nitrogen-doped carbon material according to claim 1, wherein in the step b, the carbonization is heated to 500-600 ℃ by adopting a temperature programming mode, and the heating rate is 5-15 ℃ per minute.
  5. 5. The method for preparing a bio-based nitrogen-doped carbon material according to claim 1, wherein in the step b, the carbonization time is 40 min-60 min.
  6. 6. The method for preparing the bio-based nitrogen-doped carbon material according to claim 1, wherein in the step c, the mass ratio of the purslane carbonized powder to the carbon-nitrogen mixed powder is (0.5-1): 1.5-2.
  7. 7. The bio-based nitrogen-doped carbon material is characterized by being prepared by the preparation method of the bio-based nitrogen-doped carbon material according to any one of claims 1-6.
  8. 8. A biobased nitrogen-doped carbon cathode comprising the biobased nitrogen-doped carbon material of claim 7.
  9. 9. The use of the biobased nitrogen-doped carbon cathode of claim 8 in electroflocculation coupled electrochemical oxidation treatment of printing and dyeing wastewater.
  10. 10. The method for treating the printing and dyeing wastewater by electroflocculation coupling electrochemical oxidation is characterized by comprising the following steps of: s1, adjusting the pH value of printing and dyeing wastewater to be treated to be acidic; s2, carrying out power-on electrolysis on the printing and dyeing wastewater by taking aluminum as an anode and the bio-based nitrogen-doped carbon cathode as a cathode according to claim 8, simultaneously introducing oxygen into the cathode area, standing and precipitating the electrolyzed wastewater, and carrying out solid-liquid separation to obtain the treated wastewater.

Description

Bio-based nitrogen-doped carbon material, preparation method thereof and application thereof in treatment of printing and dyeing wastewater Technical Field The invention relates to the technical field of wastewater treatment, in particular to a bio-based nitrogen-doped carbon material, a preparation method thereof and application thereof in treating printing and dyeing wastewater. Background As a key link of a textile industry chain, the printing and dyeing industry can generate a large amount of industrial wastewater with complex components and high pollutant concentration in the production process, wherein the indigo dyeing wastewater contains stable dye molecules, reductive inorganic pollutants and auxiliary agent residues, the treatment difficulty is extremely high, and if the indigo dyeing wastewater is directly discharged, serious threat is caused to a water body ecological system and human health, so that the development of an efficient and stable indigo dyeing wastewater treatment technology has become an urgent requirement in the environment protection field. Among the existing indigo dyeing wastewater treatment technologies, the electroflocculation technology has gained a great deal of attention by virtue of its unique advantages. The technology hydrolyzes and polymerizes Al 3+ dissolved out by an aluminum anode under the action of an electric field to form the aluminum hydroxy-based floc with strong adsorption performance, and can effectively capture suspended matters and partial soluble dye molecules in the wastewater to realize solid-liquid separation of pollutants. However, the single electroflocculation technology has insufficient oxidizing capability to the reducing pollutants (such as S 2O42-) in the wastewater, so that the Chemical Oxygen Demand (COD) removal rate is low, and the emission standard is difficult to meet. The electrocatalytic oxidation technology generates H 2O2 and active oxygen species in situ through Oxygen Reduction Reaction (ORR) of the cathode, and can strengthen degradation of reducing pollutants. However, most of the existing high-efficiency catalysts for driving ORR reactions are noble metal materials such as Pt, au and the like, and the high preparation cost and scarcity of the high-efficiency catalysts greatly increase the running cost of wastewater treatment and prevent the large-scale popularization and application of the technology. The bio-based material is taken as renewable resources derived from biomass in the nature, has the outstanding advantages of abundant reserves, low price, good biocompatibility, degradability and the like, can be naturally degraded or bioassimilated after being abandoned, and does not cause long-term environmental burden. The carbon-based electrode material is prepared by carbonizing the biological-based material, and accords with the concept of green sustainable development. Although the bio-based carbon material has great application potential in the aspect of being taken as an ORR catalyst, provides a new direction for optimizing an electric flocculation-electrocatalytic oxidation combined treatment system, the existing combined treatment system still faces the key technical problems that in the electric flocculation reaction process, the pH value of the system is continuously increased due to aluminum anodic hydrolysis and cathodic hydrogen evolution reaction, the pH value increase not only can inhibit the formation and adsorption activity of aluminum-based flocs and weaken the electric flocculation effect, but also can greatly reduce the adsorption capacity and electron transfer efficiency of O 2 on the surface of an electrode due to extremely sensitive ORR reaction rate and catalytic efficiency to the pH value of the reaction system, and inhibit the generation of H 2O2 and active oxygen species, so that the electric catalytic oxidation performance is attenuated. Therefore, how to screen proper bio-based carbon materials, prepare electrode materials with excellent ORR catalytic performance and pH adaptation capability, construct a wastewater treatment system capable of synergistically strengthening electric flocculation and electric catalytic oxidation effects, and have important significance for promoting development of high-efficiency treatment technology of indigo dyeing wastewater. Disclosure of Invention Aiming at the problem that the pH value is continuously increased in the treatment process of the existing electric flocculation-electrocatalytic oxidation combined wastewater treatment system to cause double attenuation of electric flocculation and electrocatalytic oxidation performance, the invention provides a bio-based nitrogen-doped carbon material, a preparation method thereof and application thereof in treating printing and dyeing wastewater. The bio-based nitrogen-doped carbon material takes natural biomass purslane and silkworm chrysalis shells as precursors, and through nitrogen doping modification, the structure