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CN-121974404-A - Preparation method and application of flower-shaped soil heavy metal ultrastable mineralizer

CN121974404ACN 121974404 ACN121974404 ACN 121974404ACN-121974404-A

Abstract

The invention relates to the technical field of treatment of heavy metal ions in soil, and discloses a preparation method and application of a flower-shaped soil heavy metal ultrastable mineralizer. The invention adopts a coprecipitation method, and provides an alkali source for a system through amino alcohol, so that a metal precursor preferentially grows along a specific direction in the reaction process, and then the nano sheet is driven to spontaneously assemble into a three-dimensional flower-shaped structure. Meanwhile, amino alcohol can expand interlayer channels and enhance the exchange capacity of the material for anions. The finally obtained hydrotalcite with the three-dimensional flower-like structure can efficiently adsorb and fix heavy metal ions in soil.

Inventors

  • FENG YONGJUN
  • JIA SHIYU
  • MENG LING
  • LI HUIYU

Assignees

  • 北京化工大学

Dates

Publication Date
20260505
Application Date
20251229

Claims (10)

  1. 1. The preparation method of the hydrotalcite with the three-dimensional flower-like structure is characterized in that amino alcohol is used as an alkali source, and the hydrotalcite with the three-dimensional flower-like structure is prepared by a coprecipitation method.
  2. 2. The production method according to claim 1, wherein the amino alcohol is at least one selected from the group consisting of triethanolamine, diethanolamine, and tromethamine.
  3. 3. The preparation method according to claim 1 or 2, wherein the method comprises the steps of dripping a metal salt solution containing divalent metal cation salt and trivalent metal cation salt into an amino alcohol solution, crystallizing, washing and drying to obtain the hydrotalcite with the three-dimensional flower-like structure.
  4. 4. A method of preparation according to claim 3, wherein the amino alcohol solution is a triethanolamine solution having a concentration of 2-3 mol/L, preferably 3 mol/L; Preferably, the amino alcohol solution is a diethanolamine solution with the concentration of 0.2-0.3 mol/L, preferably 0.3 mol/L; Preferably, the amino alcohol solution is a tromethamine solution with the concentration of 1-1.5 mol/L, preferably 1.5 mol/L; preferably, the solvent of the amino alcohol solution is water.
  5. 5. The production method according to claim 3 or 4, wherein the divalent metal cation salt is at least one selected from MgSO 4 •7H 2 O、MgCl 2 •6H 2 O、Mg(NO 3 ) 2 •6H 2 O、CaCl 2 and Ca (NO 3 ) 2 •4H 2 O; preferably, the divalent metal cation salt concentration is from 0.1 to 0.25 mol/L, preferably 0.2 mol/L.
  6. 6. The production method according to any one of claims 3 to 5, wherein the trivalent metal cation salt is selected from at least one of FeCl 3 •6H 2 O、Fe(NO 3 ) 3 •9H 2 O、AlCl 3 •6H 2 O and Al (NO 3 ) 3 •9H 2 O; Preferably, the concentration of the trivalent metal cation salt is 0.05-0.125 mol/L, preferably 0.1 mol/L.
  7. 7. The production method according to any one of claims 3 to 6, wherein a molar ratio of the divalent metal cation salt to the trivalent metal cation salt in the metal salt solution is 2 to 4:1; preferably, the volume ratio of the metal salt solution to the amino alcohol solution is 1:1.
  8. 8. The preparation process according to any one of claims 3 to 7, wherein the crystallization temperature is 60-100 ℃, preferably 80 ℃; preferably, the crystallization time is from 6 to 10 h, preferably 8h; Preferably, the washing mode comprises washing 3 times with deionized water and 1 time with ethanol; Preferably, the drying mode is freeze drying.
  9. 9. Hydrotalcite having a three-dimensional flower-like structure obtained by the production process according to any one of claims 1 to 8.
  10. 10. The use of hydrotalcite having a three-dimensional flower-like structure according to claim 9 in hyperstable mineralization of soil heavy metal ions.

Description

Preparation method and application of flower-shaped soil heavy metal ultrastable mineralizer Technical Field The invention relates to the technical field of treatment of heavy metal ions in soil, in particular to a preparation method and application of a flower-shaped soil heavy metal ultrastable mineralizer. Background Common methods include adsorption, immobilization, bioremediation and leaching methods for remediation of heavy metal ion pollution in soil. The bioremediation method has longer restoration period, the efficiency is easily influenced by environmental conditions, the microbial community structure is complex, and the secondary pollution to the soil environment is possibly caused by metabolic byproducts. The leaching principle can destroy the soil structure and physicochemical properties. Adsorption and immobilization are the most widely studied and promising methods to date. The main adsorbent materials currently under investigation include metal oxides or hydroxides such as goethite, layered Double Hydroxides (LDHs), iron oxyhydroxide and nano zero-valent iron (nZVI), as well as carbon-based adsorbents, biochars, chitosan composites and Metal Organic Frameworks (MOFs). However, most materials rely mainly on surface adsorption, and under fluctuating pH conditions and competing ions, immobilization and long-term stability are difficult to achieve by a single adsorption mechanism, and the synthesis process of some of these materials is complex, and it is difficult to meet the large-scale application requirements. The LDHs can utilize a layered framework and an adjustable interlayer environment to gradually fix and convert heavy metal ions in the environment from a free state which is easy to migrate and release again into a more stable and indissoluble mineralized state, so that hyperstable mineralization is realized. Layered Double Hydroxides (LDHs) are a class of highly designable anionic inorganic materials whose basic structure is composed of positively charged platelets together with compensating anions located between the layers. The metal cations with different valence states in the laminate are arranged in an orderly manner, and the interlayer anions and water molecules maintain overall charge balance through interaction of electrostatic interaction and hydrogen bonds, so that the material forms a stable layered framework structure. Thanks to the unique configuration, the LDHs has remarkable advantages in terms of chemical composition and microstructure regulation, namely, on one hand, the types and the proportions of metal elements in the laminate can be flexibly regulated, so that the charge density and the surface chemical property of the laminate can be effectively regulated, and on the other hand, interlayer anions have good interchangeability and intercalation characteristics. Most importantly, LDHs can be homotype substituted with LDHs laminate metal sites through exogenous ions and are embedded into a lattice structure, so that heavy metal ions are converted into a mineral-like solid solution with high stability of thermodynamics and dynamics, and long-term irreversible fixation is realized. The hyperstatic mineralization concept proposed based on the LDHs homotypic substitution strategy also receives extensive attention from related researchers in the field of soil remediation. In the existing research, magnesium-based and calcium-based LDHs exist in the form of traditional two-dimensional nano sheets or stacked sheets thereof, and the LDHs still have certain limitations in the aspects of interlayer space expansion, full exposure of interface active sites, adsorption kinetics and the like. In recent years, some documents have focused on the construction of three-dimensional hydrotalcite, and attempts have been made to improve the overall performance thereof by spatial structure control. However, the hydrotalcite often depends on a hydrothermal synthesis route with high energy consumption, or needs to introduce an external template such as MOF, polymer microsphere and the like as a structural support, and a morphology regulator is additionally added to induce a self-assembly process in part of work. In addition, although few researches have been attempted to synthesize LDHs by using an organic alkali source as a precipitant, the prepared materials are mostly concentrated in structural or catalytic performance researches, and Ni-based LDHs, such as NiCo-LDH and NiAl-LDH, are mostly used, and environmental friendliness, long-term stability and practical environmental application potential of the materials are still to be systematically evaluated, and a part of the systems still need to be combined with a hydrothermal method or an auxiliary regulation and control means to obtain an ideal morphology. In contrast, mg-based and Ca-based LDHs have the natural advantage in environmental remediation that the materials can gradually release Mg 2+ or Ca 2+ in the process of mineralizing or