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CN-117945498-B - Treatment method of sulfolane waste liquid

CN117945498BCN 117945498 BCN117945498 BCN 117945498BCN-117945498-B

Abstract

The invention provides a method for treating sulfolane waste liquid, which comprises the steps of mixing the sulfolane waste liquid with a photocatalyst, and then sequentially carrying out dark reaction and photocatalytic reaction, wherein the photocatalyst is a BiPO 4 /C 3 N 4 composite photocatalyst. The method disclosed by the invention is green, energy-saving, simple and efficient, and can convert sulfolane in the sulfolane waste liquid into cyclobutane and sulfuric acid under the conditions of normal temperature and normal pressure and no external organic reagent. According to the method, the cyclobutane directly overflows in a gas form, so that the time and energy consumption cost caused by waste liquid separation are reduced, small molecular organic pollutants in the sulfolane waste liquid are degraded under the photocatalytic effect, and only sulfuric acid and a small amount of original inorganic salt generated by the reaction are reserved after the degradation.

Inventors

  • LIU YANFANG
  • LI CHENGHAO
  • WANG ZHIQIANG
  • HOU JILI
  • ZOU LIANG
  • CUI LONGPENG

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260505
Application Date
20221027

Claims (20)

  1. 1. A method for treating sulfolane waste liquid is characterized by mixing the sulfolane waste liquid with a photocatalyst and then sequentially carrying out dark reaction and photocatalytic reaction, wherein the photocatalyst is a BiPO 4 /C 3 N 4 composite photocatalyst; taking the volume of the sulfolane waste liquid as a reference, the addition amount of the BiPO 4 /C 3 N 4 composite photocatalyst is 0.1-5 g/L; The preparation method of the BiPO 4 /C 3 N 4 composite photocatalyst comprises the following steps: s1, mixing phosphate aqueous solution and bismuth nitrate aqueous solution to obtain a suspension containing a BiPO 4 precursor; S2, mixing the suspension containing the BiPO 4 precursor with melamine and heating to obtain a first mixed material; S3, centrifugally separating the first mixed material to obtain solid powder; The BiPO 4 /C 3 N 4 composite photocatalyst comprises a BiPO 4 nucleus body and C 3 N 4 particles which are attached to the surface of the BiPO 4 nucleus body in the form of quantum dots; Based on the total weight of the BiPO 4 /C 3 N 4 composite photocatalyst, the weight percentage of BiPO 4 is 60-90%, and the weight percentage of C 3 N 4 is 10-40%; the specific surface area of the BiPO 4 /C 3 N 4 composite photocatalyst is 2-50m 2 /g.
  2. 2. The method of claim 1, wherein the BiPO 4 is 65-85% by weight based on the total weight of the BiPO 4 /C 3 N 4 composite photocatalyst.
  3. 3. The method of claim 1, wherein the weight percent of C 3 N 4 is 15-35% based on the total weight of the BiPO 4 /C 3 N 4 composite photocatalyst.
  4. 4. The method of claim 1, wherein the specific surface area of the BiPO 4 /C 3 N 4 composite photocatalyst is 4-40m 2 /g.
  5. 5. The method of claim 1, wherein the amount of the BiPO 4 /C 3 N 4 composite photocatalyst added is 0.3-3 g/L based on the volume of the sulfolane waste liquid.
  6. 6. The method of claim 1, wherein the sulfolane waste liquid has a COD of 50-2500 mg/L, sulfolane concentration of 10-200 mg/L, acetic acid concentration of 0-1000 mg/L, and sulfate concentration of 0-100 mg/L.
  7. 7. The method according to claim 1, wherein the dark reaction condition comprises light intensity of not more than 0.2mW/cm 2 for 10-60 min, and the photocatalytic reaction condition comprises light intensity of 20-80 mW/cm 2 and light irradiation time of 2-6 h.
  8. 8. The method of claim 1, wherein the dark reaction has a light intensity of no more than 0.1mW/cm 2 .
  9. 9. The method of claim 1, wherein the dark reaction time is 20-40 min.
  10. 10. The method of claim 1, wherein the photocatalytic reaction is performed under illumination from a xenon lamp.
  11. 11. The method of claim 10, wherein the xenon lamp is a 300W xenon lamp preloaded with a 400-800 nm filter.
  12. 12. The method of claim 1, wherein the bismuth nitrate aqueous solution has a concentration of 0.060-0.100 mol/L and the phosphate aqueous solution has a concentration of 0.100-0.350 mol/L; The volume ratio of the bismuth nitrate aqueous solution to the phosphate aqueous solution is 1:0.5-1.5.
  13. 13. The method of claim 1, wherein the bismuth nitrate aqueous solution has a concentration of 0.070-0.090 mol/L.
  14. 14. The method according to claim 1, wherein the concentration of the phosphate aqueous solution is 0.150-0.300 mol/L.
  15. 15. The method of claim 1, wherein the bismuth nitrate aqueous solution and the phosphate aqueous solution are mixed in a volume ratio of 1:0.8-1.2.
  16. 16. The method of claim 1, wherein the phosphate is at least one of NaH 2 PO 4 、Na 2 HPO 4 and Na 3 PO 4 .
  17. 17. The method of claim 1, wherein the phosphate is NaH 2 PO 4 .
  18. 18. The method according to claim 1, wherein the bismuth nitrate is bismuth nitrate pentahydrate, and the mass ratio of the melamine to the bismuth nitrate pentahydrate is 0.10-0.70.
  19. 19. The method of claim 18, wherein the mass ratio of melamine to bismuth nitrate pentahydrate is 0.15-0.61.
  20. 20. The method of claim 1, wherein, In the step S1, the mixing comprises stirring treatment, wherein the stirring treatment conditions comprise 15-45 min and 25-30 ℃; In the step S2, the heating treatment conditions comprise that the temperature is 90-130 ℃ and the time is 800-160 min; in the step S3, the centrifugal separation condition comprises the time of 20-40 min and the rotating speed of 3000-5000 r/min, and the calcination condition comprises the temperature of 400-600 ℃ and the time of 90-200 min.

Description

Treatment method of sulfolane waste liquid Technical Field The disclosure relates to the field of waste liquid treatment, in particular to a method for treating sulfolane waste liquid. Background Sulfolane waste liquid is a hazardous waste produced by aromatic hydrocarbon units. At present, for the treatment of sulfolane waste liquid, a distillation method is mainly adopted in industry, and the evaporation method has very high energy consumption due to high moisture content in the waste liquid, and side reactions such as sulfolane ring opening and the like are easily caused at high temperature. When the sulfolane waste liquid is treated by the biochemical method, the sulfolane is degraded into carbon dioxide, sulfur dioxide and the like, and cannot be recycled. Therefore, the efficient and energy-saving technology for harmless recycling of sulfolane waste liquid becomes a urgent market demand. In recent years, the recycling technology of sulfolane waste liquid is focused by the technicians in the field, for example, the delayed coking technology is adopted in the loyang petrochemical industry, sulfolane is sent to the top of a coke tower for recycling, a green channel is opened up for the treatment of sulfolane waste agent, but because the sulfur content in sulfolane is higher, harmful waste gas such as hydrogen sulfide or sulfur dioxide is generated in the process, the waste gas treatment burden is increased, and the energy consumption is higher. Patent document 200610134285.3 discloses a method for recovering sulfolane containing inorganic salt, which comprises the steps of separating out inorganic salt by adopting a filter aid, and distilling the filter aid by reduced pressure distillation, so that the inorganic salt in the sulfolane is removed. The patent literature 201810857047.8 adopts an extraction method to recycle sulfolane in the waste liquid, the concentration of the sulfolane in the treated waste liquid is lower than 50mg/L, but the extracting agent adopted by the method is one or a mixture of more than two of halohydrocarbon, aromatic hydrocarbon and ester compounds, the using amount is large, small molecular organic pollutants in the waste liquid can not be removed, although the concentration of the sulfolane in the treated waste liquid can be lower than 50mg/L, COD can still be higher than 100mg/L, the waste liquid can not reach the standard and is discharged, and the recycling of the treated waste water is also more limited due to the existence of small molecular organic matters and inorganic salts. Disclosure of Invention The method aims at solving the problems of high energy consumption, high toxicity and difficult removal of micromolecular organic pollutants in the sulfolane waste liquid treatment process. In order to achieve the above purpose, the disclosure provides a method for treating sulfolane waste liquid, which mixes the sulfolane waste liquid with a photocatalyst and then sequentially performs dark reaction and photocatalytic reaction, wherein the photocatalyst is a BiPO 4/C3N4 composite photocatalyst. Optionally, the BiPO 4/C3N4 composite photocatalyst comprises a BiPO 4 nucleus body and C 3N4 particles attached to the surface of the BiPO 4 nucleus body in a quantum dot form, wherein the weight percentage of the BiPO 4 is 60-90%, preferably 65-85%, the weight percentage of the C 3N4 is 10-40%, preferably 15-35% based on the total weight of the BiPO 4/C3N4 composite photocatalyst, and the specific surface area of the BiPO 4/C3N4 composite photocatalyst is 2-50m 2/g, preferably 4-40m 2/g. Optionally, the addition amount of the BiPO 4/C3N4 composite photocatalyst is 0.1-5 g/L, preferably 0.3-3 g/L based on the volume of the sulfolane waste liquid. Optionally, the COD of the sulfolane waste liquid is 20-2500 mg/L, the sulfolane concentration is 10-200 mg/L, the acetic acid concentration is 0-1000 mg/L, and the sulfate radical concentration is 0-100 mg/L. Optionally, the dark reaction condition comprises light intensity not exceeding 0.2mW/cm 2, preferably not exceeding 0.1mW/cm 2, time being 10-60 min, preferably 20-40 min, the photocatalysis reaction condition comprises light intensity being 20-80 mW/cm 2, light time being 2-6 h, preferably the photocatalysis reaction is carried out under light of a xenon lamp, and further preferably the xenon lamp is a 300W xenon lamp preloaded with a 400-800 nm optical filter. Optionally, the preparation method of the BiPO 4/C3N4 composite photocatalyst comprises the following steps: s1, mixing phosphate aqueous solution and bismuth nitrate aqueous solution to obtain a suspension containing a BiPO 4 precursor; S2, mixing the suspension containing the BiPO 4 precursor with melamine and heating to obtain a first mixed material; s3, centrifugally separating the second mixed material to obtain solid powder, and calcining the solid powder. Optionally, the concentration of the bismuth nitrate aqueous solution is 0.060-0.100 mol/L, preferably 0.070-0.09