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CN-121988303-A - Method for preparing composite adsorption material based on phosphogypsum and sludge co-pyrolysis and application thereof

CN121988303ACN 121988303 ACN121988303 ACN 121988303ACN-121988303-A

Abstract

The invention provides a method for preparing a composite adsorption material based on phosphogypsum and sludge co-pyrolysis, which comprises the steps of preparing phosphogypsum crushed material and sludge crushed material, mixing the phosphogypsum crushed material and the sludge crushed material to prepare a dried mixture, heating to 300-500 ℃ in an inert protective gas atmosphere, carrying out constant-temperature pyrolysis for 0.5-2 h, heating to 700-900 ℃ again, carrying out constant-temperature pyrolysis for 0.5-4 h, and naturally cooling to room temperature in the inert protective gas atmosphere to obtain the composite adsorption material. According to the invention, the temperature evolution in the co-pyrolysis process is controlled, so that the sludge and phosphogypsum play a leading role in different stages, the sludge is used as a carrier, and the composite adsorption material is prepared by the cooperation of the sludge and the phosphogypsum, so that the adsorption rate of phosphorus and heavy metals in sewage and wastewater and the removal rate of organic matters can be remarkably improved.

Inventors

  • XU LONGHUA
  • REN JUNTAO
  • OU YANG
  • TIAN JIA
  • LUO YI
  • WANG LEI

Assignees

  • 西南科技大学
  • 磷净未来科技(四川)有限责任公司

Dates

Publication Date
20260508
Application Date
20260225

Claims (8)

  1. 1. A method for preparing a composite adsorption material based on phosphogypsum and sludge co-pyrolysis is characterized by comprising the following steps: s1, drying phosphogypsum to constant weight at the temperature of 80-110 ℃, and screening after crushing to obtain phosphogypsum crushed materials; S2, drying the sludge to constant weight at the temperature of 80-110 ℃, and screening the crushed sludge to obtain a sludge crushed material; S3, mixing the phosphogypsum crushed material obtained in the step S1 with the sludge crushed material obtained in the step S2 to obtain a crushed material mixture, adding deionized water, stirring and mixing, and drying at the temperature of 80-110 ℃ to obtain a dried mixture; And S4, heating the dried mixture obtained in the step S3 to 300-500 ℃ from room temperature at a heating rate of 5-10 ℃ per minute under an inert protective gas atmosphere, performing constant-temperature pyrolysis for 0.5-2 h, heating to 700-900 ℃ at a heating rate of 5-10 ℃ per minute, performing constant-temperature pyrolysis for 0.5-4 h, and naturally cooling to room temperature under the inert protective gas atmosphere to obtain the composite adsorbing material.
  2. 2. The method for preparing the composite adsorbing material based on the co-pyrolysis of phosphogypsum and sludge, which is disclosed in claim 1, is characterized in that the mass fraction of the phosphogypsum crushed material with the particle size less than or equal to 44 μm in S1 is more than 80%, and the mass fraction of the phosphogypsum crushed material with the particle size less than or equal to 44 μm in S2 is more than 80%.
  3. 3. The method for preparing the composite adsorption material based on the co-pyrolysis of phosphogypsum and sludge, which is characterized in that the mass fraction of phosphogypsum crushed material in the crushed material mixture in the step S3 is 50% -90%.
  4. 4. The method for preparing the composite adsorption material based on phosphogypsum and sludge co-pyrolysis according to claim 1, wherein the mass ratio of the crushed material mixture to deionized water in S3 is (0.5-2): 1.
  5. 5. The method for preparing the composite adsorption material based on phosphogypsum and sludge co-pyrolysis according to claim 1, wherein the drying time in S3 is 6-8 hours.
  6. 6. The method for preparing the composite adsorption material based on phosphogypsum and sludge co-pyrolysis according to claim 1, wherein the inert shielding gas in S4 is N 2 , the gas flow rate is 50-400 mL/min, and the gas concentration is >99.9%.
  7. 7. Use of a composite adsorbent material prepared according to the method of any one of claims 1-6, in the treatment of sewage containing phosphates, heavy metals and/or organic matter.
  8. 8. The use according to claim 7, wherein the composite adsorbent material is used for the removal of P, pb (II), cd (II) and/or sulfamethoxazole under acidic conditions.

Description

Method for preparing composite adsorption material based on phosphogypsum and sludge co-pyrolysis and application thereof Technical Field The invention belongs to the technical field of solid waste recycling and water pollution control, and particularly relates to a method for preparing a composite adsorption material based on phosphogypsum and sludge co-pyrolysis and application thereof. Background Phosphogypsum is used as a byproduct of the wet phosphoric acid process, and 4-5 tons of phosphogypsum can be produced every 1 ton of phosphoric acid. Phosphogypsum is piled up, occupies a large area of land, is exposed to the air for a long time, generates dust to pollute the air after being blown by wind, sun and rain, and soluble phosphorus and fluorine can enter water and soil to cause environmental pollution and harm the health of human bodies. Meanwhile, phosphogypsum is rich in resource components such as calcium, sulfur and the like, and resource waste is caused by the low-efficiency utilization of the phosphogypsum. At present, phosphogypsum is widely applied to the fields of soil remediation, cement retarder and the like, but the phosphogypsum is limited in use due to the existence of P, F and other impurities. Some studies have attempted to use phosphogypsum for the preparation of the adsorbent material to exert the functional effect of the inorganic component contained therein. However, because phosphogypsum has compact structure, small specific surface area and undeveloped pore structure, efficient adsorption structure is difficult to construct effectively, and the adsorptivity and application stability are still limited. The residual sludge is used as a byproduct in the sewage treatment process, contains a large amount of organic matters and pathogenic microorganisms, is accompanied with a certain amount of inorganic mineral components, and has the composition characteristics which are obviously different from those of conventional biomass materials mainly containing cellulose, such as straw, wood dust and the like. The conventional biomass material has low inorganic mineral content, mainly plays a role in providing a carbon source, is difficult to participate in constructing active sites in the pyrolysis process, and has limited adsorptivity and selectivity. The residual sludge not only can form a carbon phase structure under the pyrolysis condition, but also can construct a functional structure of the adsorption material. The residual sludge has higher ash content, can be made into a carbon skeleton and induce the formation of a pore structure in the pyrolysis process, and is favorable for the adsorption material to construct a system with rich pores and stable structure. In recent years, there have been studies on conversion of excess sludge into biochar materials for contaminant adsorption by pyrolysis technology. However, the existing researches mostly adopt single raw materials or simple compounding treatment, and the reaction behaviors of different raw materials are not controlled in a targeted manner in the pyrolysis process. In the pyrolysis process, the thermal decomposition characteristics, the reactivity and the structural evolution rules of different raw materials are obviously different, if the raw materials are simply mixed and roasted, the synergistic effect of the different raw materials in the pyrolysis process can not be fully exerted, and particularly in the aspect of in-situ compounding of inorganic functional components and a carbon phase structure, the obtained material has an uneven structure, and the utilization efficiency, the adsorption performance and the like of active sites are to be improved. Disclosure of Invention The invention aims to solve the technical problems of the prior art and provides a method for preparing a composite adsorption material based on phosphogypsum and sludge co-pyrolysis and application thereof, wherein the method controls the temperature evolution in the co-pyrolysis process, the sludge and phosphogypsum play a leading role in different stages, the sludge is taken as a carrier, and the composite adsorption material is prepared by the cooperation of the sludge and the phosphogypsum, so that the adsorption rate of phosphorus and heavy metals in sewage and wastewater and the removal rate of organic matters can be remarkably improved. In order to solve the technical problems, the invention adopts the technical scheme that the method for preparing the composite adsorption material based on phosphogypsum and sludge co-pyrolysis comprises the following steps of: s1, drying phosphogypsum to constant weight at the temperature of 80-110 ℃, and screening after crushing to obtain phosphogypsum crushed materials; S2, drying the sludge to constant weight at the temperature of 80-110 ℃, and screening the crushed sludge to obtain a sludge crushed material; The sludge is a byproduct generated in the sewage treatment process of the urban sewage treatment plant