Search

CN-122006616-A - Method for decoloring polyaspartate based on cooperation of ozone, sodium peroxycarbonate and citric acid

CN122006616ACN 122006616 ACN122006616 ACN 122006616ACN-122006616-A

Abstract

The invention discloses a decoloring method for polyaspartate based on the synergy of ozone, sodium peroxycarbonate and citric acid, the decoloring method is that the polyaspartate solution is firstly subjected to primary oxidative decoloring treatment by the cooperation of ozone and sodium peroxycarbonate, and then is subjected to secondary oxidative decoloring treatment by the cooperation of citric acid and ozone. According to the decoloring method disclosed by the invention, ozone is used as a main decoloring agent, and the decoloring effect on polyaspartate is obviously improved by sequentially carrying out the synergistic decoloring of ozone and sodium peroxycarbonate and the synergistic decoloring of ozone and citric acid, so that the influence on the molecular structure of polyaspartate is greatly reduced, and the high quality of polyaspartate products is ensured.

Inventors

  • ZHANG YUZHUO
  • JIAO YONGKANG
  • SUN DECHUN
  • CUI XIAOMING
  • ZHAO LONGMEI

Assignees

  • 河北协同化学有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. A method for decoloring polyaspartate based on the cooperation of ozone, sodium peroxycarbonate and citric acid is characterized in that the method is that the polyaspartate solution is subjected to primary oxidation decoloring treatment by the cooperation of ozone and sodium peroxycarbonate, and then is subjected to secondary oxidation decoloring treatment by the cooperation of citric acid and ozone, so that the absorbance of 480nm of the decolored system solution is not more than 0.054, and the molecular weight change rate of polyaspartate is not more than 8%.
  2. 2. The method for decoloring polyaspartate based on the cooperation of ozone, sodium peroxycarbonate and citric acid is characterized by comprising the steps of preliminary oxidation decoloring treatment, introducing ozone into polyaspartate solution, adding sodium peroxycarbonate after the ozone concentration reaches 20-30 mg/L, maintaining the pH of the system at 8.0-10.0, and continuously stirring for decoloring reaction.
  3. 3. The method for decoloring polyaspartate based on the synergy of ozone, sodium peroxycarbonate and citric acid according to claim 2 is characterized in that the preliminary oxidative decoloring is judged to be completed until the chromaticity of a system solution is basically unchanged within 15 minutes.
  4. 4. The method for decoloring polyaspartate based on the cooperation of ozone, sodium carbonate peroxide and citric acid according to claim 3 is characterized by comprising the steps of performing secondary oxidation decoloring treatment, adding citric acid into a system subjected to primary oxidation decoloring to maintain the pH of the system at 6.0-7.0, and then introducing ozone to perform secondary oxidation decoloring, wherein the ozone concentration reaches 40-50 mg/L.
  5. 5. The method for decoloring polyaspartate based on ozone-sodium peroxycarbonate-citric acid cooperation according to claim 1 is characterized in that the concentration of polyaspartate solution is 15-25% w/v, and/or the adding amount of sodium peroxycarbonate is 0.5-2% w/v of polyaspartate solution, and/or the mass ratio of citric acid adding amount to sodium peroxycarbonate is 0.8-1.5:1.
  6. 6. The method for decoloring polyaspartate based on the synergy of ozone, sodium carbonate peroxide and citric acid according to claim 1, wherein the ozone-charging operation in the primary oxidation decoloring treatment and the secondary oxidation decoloring treatment are both in a batch mode.
  7. 7. The method for decoloring polyaspartate based on the cooperation of ozone, sodium carbonate peroxide and citric acid according to claim 6, wherein the primary oxidation decoloring treatment process is characterized in that the ozone is introduced in a mode of being introduced for 5-6 min, and is stopped for 2-3 min and circulated for 3-4 times, and/or the secondary oxidation decoloring treatment process is performed in a mode of being introduced for 5-6 min, and is stopped for 2-3 min and circulated for 3-6 times.
  8. 8. The method for decoloring polyaspartate based on the synergy of ozone-sodium peroxycarbonate and citric acid according to any one of claims 1 to 7, wherein the decoloring method comprises the following operation steps: a. Preparing raw materials, namely preparing polyaspartate solution with the concentration of 15-25% w/v, and controlling the initial pH value to be 6.5-8.5; b. And (3) decoloring: b1, preliminary oxidation and decolorization, namely introducing ozone into polyaspartate solution in an intermittent mode, introducing the ozone for 5-6 min each time, stopping the gas for 2-3 min, circulating for 3-4 times to ensure that the ozone introducing concentration reaches 20-30 mg/L, then adding sodium peroxycarbonate, dissolving and reacting under the stirring condition of 200-300 r/min to ensure that the pH value of the system is maintained at 8.0-10.0, continuously stirring for decolorization, and finishing the preliminary oxidation and decolorization when the chromaticity of the system solution is basically unchanged for 15 min; Adding citric acid into the system subjected to primary oxidation and decolorization to maintain the pH of the system at 6.0-7.0, then introducing ozone in an intermittent mode for secondary oxidation and decolorization, introducing air for 5-6 min each time, stopping air for 2-3 min, circulating for 3-6 times to ensure that the ozone introducing concentration reaches 40-50 mg/L, and continuously stirring until the absorbance of the system solution at 480nm wavelength is less than or equal to 0.054, thereby finishing secondary oxidation and decolorization; Preferably, the volume expansion of the process control system solution added with sodium peroxycarbonate and citric acid in steps b1 and b2 respectively is not more than 1.2 times; c. and (3) after the decoloration is finished, continuously stirring for 20-30 min to remove residual ozone, and preparing the polyaspartate product.
  9. 9. The method for decoloring polyaspartate based on the synergy of ozone, sodium peroxycarbonate and citric acid according to claim 8, wherein ozone is introduced through a microbubble jet aerator by using an ozone generator.
  10. 10. The method for decoloring polyaspartate based on the synergy of ozone, sodium peroxycarbonate and citric acid according to claim 8, wherein the polyaspartate solution obtained after decoloring and removing residual ozone is concentrated and/or dried according to requirements to obtain a polyaspartate product with HAZEN chromaticity lower than 450.

Description

Method for decoloring polyaspartate based on cooperation of ozone, sodium peroxycarbonate and citric acid Technical Field The invention relates to the technical field of decoloration of polyaspartate products, in particular to a method for decoloring polyaspartate based on the cooperation of ozone, sodium peroxycarbonate and citric acid. Background Polyaspartic Acid (PASP) is used as an environment-friendly polymer material, has good chelating property and biodegradability, and is widely applied to the fields of water treatment, spinning, medicine and the like. Currently, poly (aspartic acid) products are mainly prepared into Polysuccinimide (PSI) through thermal condensation of L-aspartic acid, and then are prepared into polyaspartate (such as sodium polyaspartate, potassium polyaspartate, ammonium polyaspartate, calcium polyaspartate, magnesium polyaspartate, zinc polyaspartate and the like) through alkaline hydrolysis. In the thermal condensation and hydrolysis process, the product often presents pale yellow to reddish brown due to the fact that the chromophoric group with the conjugated structure is easy to generate, which affects the application of the polyaspartate in the fields of daily chemicals, cosmetics and the like, so that the solution of the color problem of the polyaspartate has important value for popularization in the daily chemicals field. The prior decoloring technology mainly adopts a physical adsorption method and a chemical decoloring method. The physical adsorption generally uses activated carbon as an adsorbent, the adsorption efficiency is low, thorough decolorization cannot be realized, the purity of the product is reduced, and solid waste pollution is generated. The chemical decolorization is mainly carried out by adopting a hydrogen peroxide and sodium peroxycarbonate oxidation method, the oxidation decolorization method has the problems of long reaction time and large molecular weight change (more than 15%) of polyaspartate, and the required temperature condition (more than 60 ℃) can further aggravate the oxidability, damage the molecular weight side chain of the polyaspartate and influence the original performance of the product. Therefore, the traditional decoloring method has defects, and is difficult to meet the application requirements of high efficiency, environmental protection and low cost. Ozone is taken as a strong oxidant, can break chemical bonds of organic chromophores, is decomposed into small molecular substances such as carbon dioxide, water and the like, does not have residual pollutants after reaction, meets the requirements of high efficiency and environmental protection, so an ozone oxidation method has been developed into a decoloring technology in recent years, but has the problems that the decoloring effect is limited (such as the decoloring rate of ozone on polyaspartate is less than 90 percent and the chromaticity requirement of high-quality products cannot be met) due to low utilization rate of ozone as the ozone is in a gaseous state, and the running cost is lost, so the conventional ozone application scene is mostly concentrated on polymer surface treatment and wastewater decoloring, and has no related report on the application of polyaspartate decoloring, so the method has the advantages of accurately controlling the oxidizing conditions, keeping the original performance of polyaspartate to the maximum extent while realizing high-efficiency decoloring, and becoming the core problem of the oxidation decoloring technology. Disclosure of Invention The invention provides a method for decoloring polyaspartate based on the synergy of ozone, sodium peroxycarbonate and citric acid, which aims to solve the problems that the decoloring effect is limited, the decoloring requirement cannot be met or the molecular weight is greatly reduced due to the fact that the decoloring requirement cannot be met in the oxidation decoloring process of polyaspartate. In order to achieve the purpose, the method for decoloring polyaspartate based on the cooperation of ozone, sodium peroxycarbonate and citric acid provided by the invention is characterized in that the polyaspartate solution is subjected to primary oxidation decoloring treatment by the cooperation of ozone and sodium peroxycarbonate, and then is subjected to secondary oxidation decoloring treatment by the cooperation of citric acid and ozone, so that the absorbance of 480nm of the decolored system solution is not more than 0.054, and the molecular weight change rate of polyaspartate is not more than 8%. According to the decoloring method, ozone is introduced in two stages, and the ozone is respectively and effectively cooperated with sodium peroxycarbonate and citric acid to generate an action mechanism, so that the decoloring rate is remarkably improved, the influence on the molecular structure of polyaspartate is reduced, the color problem of a high-quality product is solved, and the polyaspartate product with u