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CN-122013168-A - Environment-friendly rust conversion agent and preparation method thereof

CN122013168ACN 122013168 ACN122013168 ACN 122013168ACN-122013168-A

Abstract

The invention discloses an environment-friendly rust conversion agent and a preparation method thereof, wherein a tea polyphenol-tannic acid-ascorbic acid-sodium gluconate food-grade quaternary synergistic conversion system is constructed, chelate precipitation is inhibited through specific coordination of sodium gluconate and Fe 3+ , the problem that the existing plant extract conversion agent is easy to lose effectiveness in storage is solved, quantitative judgment of a reaction end point is realized through pH response of purple cabbage anthocyanin and color development reaction of potassium ferrocyanide-Fe 3+ , the visualization is good, and the environment-friendly rust conversion agent has the advantages of safety, no toxicity, low cost, high stability, strong education adaptability and the like, and can be widely applied to maintenance of household metal appliances, protection of small-sized metal artworks, and teenager chemistry experiment teaching.

Inventors

  • Li Durui
  • Lv Zian
  • Tian Shitian
  • LI SHEFENG

Assignees

  • 李杜睿

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The environment-friendly rust conversion agent is characterized by comprising, by mass, 4-6% of tea polyphenol, 2-4% of tannic acid, 1-3% of a natural reducing agent, 1-2% of sodium gluconate, 0.3-0.7% of a purple cabbage concentrated solution, 0.1% of potassium ferrocyanide and the balance of deionized water.
  2. 2. The environment-friendly rust converting agent according to claim 1, wherein the natural reducing agent is vitamin C and/or vitamin E.
  3. 3. The environment-friendly rust converting agent according to claim 1, wherein the pH value of the environment-friendly rust converting agent is 3.8-4.2.
  4. 4. The environment-friendly rust converting agent according to claim 3, wherein the pH is adjusted by adding sodium citrate-malic acid buffer.
  5. 5. The environment-friendly rust conversion agent according to claim 4, wherein the mass ratio of sodium citrate to malic acid in the sodium citrate-malic acid buffer is 3:2, and the concentration of the buffer is more than or equal to 0.05mmol/L.
  6. 6. The environment-friendly rust conversion agent according to claim 1, wherein the purple cabbage concentrated solution is obtained by squeezing fresh purple cabbage, the squeezing rate is more than or equal to 80%, and the anthocyanin content is more than or equal to 0.1%.
  7. 7. The method for preparing the environment-friendly rust conversion agent according to any one of claims 1 to 6, characterized by comprising the steps of: s1, preparing a pH buffer solution; S2, adding a natural reducing agent and sodium gluconate into the buffer solution, and uniformly stirring; S3, sequentially adding tea polyphenol and tannic acid for full dissolution; s4, adding the purple cabbage concentrated solution and potassium ferrocyanide; s5, filtering the solution prepared in the step S4 to obtain the environment-friendly rust conversion agent.
  8. 8. The method according to claim 7, wherein the tea polyphenol and/or tannic acid dissolution process is heated.
  9. 9. The method of claim 7, wherein the filtration is performed using a 0.4-2 μm filter.
  10. 10. The rust conversion experiment teaching aid kit is characterized by comprising the environment-friendly rust conversion agent according to any one of claims 1-6 and an auxiliary tool, wherein the auxiliary tool comprises at least one of a pH detection tool, a color recognition tool and a calculation tool.

Description

Environment-friendly rust conversion agent and preparation method thereof Technical Field The invention belongs to the technical field of metal surface treatment, and particularly relates to an environment-friendly rust conversion agent and a preparation method thereof. Background Metal tarnishing (Fe 2O3·nH2 O as the major component) is the primary cause of failure in domestic and small metal products, and low cost, safe treatment solutions are needed. The prior art has the following key drawbacks, and no patent or literature has proposed systematic solutions. Technical bottlenecks of existing converter systems include: the plant extract type conversion agent is characterized in that the tannic acid-based conversion agent disclosed in Chinese patent CN2019102832.5 only adopts a single plant extract, the conversion efficiency is low (more than 30 minutes are needed for treating rusted cast iron) and no stabilizer is added, the chelate precipitation rate reaches 5.2% after 30 ℃ accelerated aging for one week, the long-term storage requirement of families cannot be met, the tannic acid-organic acid system of Japanese patent JP2018052693 improves the conversion rate, but contains trace corrosive organic acid (such as citric acid derivatives), and skin irritation test (rabbits) shows slight red swelling and cannot be used for teenager experiments. The synthetic chelating agent converting agent is commercial EDTA and DTPA products (such as environmental protection rust remover of certain brand) with poor biodegradability (BOD 5/COD < 0.3), the conversion efficiency is reduced by 3.1% after 30 ℃ accelerated aging for one week, the raw materials need to be purchased in a professional chemical industry channel (the household users do not have purchasing qualification), and the cost of single-treatment household iron pan exceeds 0.5 yuan (the cost performance is low) The corrosion rate of phosphoric acid and hydrochloric acid products (such as certain industrial rust remover) to metal matrix reaches more than 0.1 mm/year, the pH value of waste liquid is less than 2, and the random discharge can lead to the reduction of the pH value of soil by 0.5-1.0 unit (according to the research data of volume 42 of environmental chemistry 2023), which is not suitable for families and educational scenes. In the field of teenager STEM education (science, technology, engineering and mathematical cross-fusion education) tools, the following drawbacks exist: 1) The education suitability is lacking, the existing transforming agent is not designed aiming at the teenager cognitive characteristics, the relation of 'visualization phenomenon-basic principle' is lacking in the junior middle stage (such as no corresponding teaching module of color change and pH), the experimental support of 'quantitative analysis-advanced principle' is lacking in the junior middle stage (such as no chelate stability constant measurement scheme), and the transforming agent cannot be integrated into a STEM course system. 2) The household use threshold is high, the commercial conversion agent is prepared at high temperature and high pressure (for example, a certain product needs to react for 2 hours at 120 ℃ and 0.2 MPa), the household user does not have professional equipment, part of the product needs to accurately control the concentration (error +/-0.1%), and the operation failure rate of non-professional personnel is more than 40% (based on the investigation data of 100 household users). 3) The reaction process is uncontrollable, the existing product only depends on a single pH indicator (such as phenolphthalein and methyl orange), whether Fe 3+ is completely converted or not can not be judged, excessive treatment often causes thinning of an iron pan or insufficient treatment causes rust recovery within 1 month, and the feedback satisfaction degree of household users is only 52%. In summary, it is necessary to overcome the drawbacks of the prior art and develop a rust conversion agent with environmental protection, stability and high conversion rate to meet the requirements of STEM education tools for teenagers. Disclosure of Invention In view of the above, the invention aims to provide an iron rust transforming agent which has the advantages of environmental protection, stability and high transformation rate, so as to be popularized and applied to STEM education tools of teenagers. In order to solve the problems, the scheme of the invention is as follows: The first aspect of the invention provides an environment-friendly rust conversion agent which comprises, by mass, 4-6% of tea polyphenol, 2-4% of tannic acid, 1-3% of a natural reducing agent, 1-2% of sodium gluconate, 0.3-0.7% of purple cabbage concentrate, 0.1% of potassium ferrocyanide and the balance of deionized water. Further, the natural reducing agent is vitamin C and/or vitamin E. Further, the pH value of the environment-friendly rust conversion agent is 3.8-4.2. Preferably, the pH is adjusted