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CN-121972145-A - Preparation method of magnesium-iron mineral loaded amphoteric polymer heavy metal adsorbent

CN121972145ACN 121972145 ACN121972145 ACN 121972145ACN-121972145-A

Abstract

The invention provides a preparation method of a modified magnesium-iron mineral supported amphoteric polymer heavy metal adsorbent, which comprises the steps of firstly, preprocessing a mineral matrix, namely crushing, grinding and sieving raw magnesium-iron ores to obtain mineral powder, grinding and sieving biochar to obtain biochar, placing the mineral powder and the biochar in a muffle furnace for calcination and activation, and naturally cooling to obtain a calcined modified mineral matrix, secondly, preparing a precursor dispersion liquid, namely, adding the calcined modified mineral matrix into an organic solvent, performing ultrasonic dispersion for 20-40 min at room temperature to obtain a uniform mineral dispersion liquid, sequentially adding an amino monomer, an acrylic monomer, a cross-linking agent and an initiator into the dispersion liquid, stirring and mixing uniformly to obtain a polymer precursor liquid, thirdly, performing in-situ polymerization reaction, namely, continuously introducing nitrogen into the polymer precursor liquid to remove air in a system, sealing and then placing the polymer precursor liquid in a constant-temperature environment for in-situ free radical polymerization reaction to obtain a solid-phase product, and secondly, sequentially washing the solid-phase product with methanol and deionized water for multiple times to remove unreacted monomers and oligomer impurities, and drying, grinding and sieving to obtain the magnesium-iron mineral supported amphoteric polymer heavy metal adsorbent. The method can be flexibly applied according to the pH characteristics of the actual wastewater, and the defect that the traditional adsorbent can only treat single type heavy metals or needs frequent pH adjustment is overcome.

Inventors

  • WANG QIYANG
  • ZHANG YEXIN
  • DUAN MING
  • WANG JINGYUAN
  • Gong Hangpeng
  • ZHAO YUAN
  • HOU HAIXIN

Assignees

  • 中国地质大学（北京）

Dates

Publication Date
20260505
Application Date
20260318

Claims (10)

  1. 1. The preparation method of the modified mafic mineral loaded amphoteric polymer heavy metal adsorbent is characterized by comprising the following steps of: I. Mineral matrix pretreatment, namely crushing, grinding and sieving the mafic raw ore to obtain mineral powder, grinding and sieving the biochar to obtain biochar, placing the mineral powder and the biochar into a muffle furnace for calcination and activation, and naturally cooling to obtain a calcined modified mineral matrix; Step II, preparing a precursor dispersion liquid, namely adding a calcined modified mineral matrix into an organic solvent, performing ultrasonic dispersion at room temperature for 20-40 min to obtain a uniform mineral dispersion liquid, sequentially adding an amino monomer, an acrylic monomer, a crosslinking agent and an initiator into the dispersion liquid, and uniformly stirring and mixing to obtain a polymerization precursor liquid; III, in-situ polymerization reaction, namely continuously introducing nitrogen into the polymerization precursor liquid to remove air in the system, sealing, and then placing the mixture in a constant temperature environment to perform in-situ free radical polymerization reaction to obtain a solid phase product; and IV, post-treatment, namely washing the solid phase product with methanol and deionized water for multiple times in sequence to remove unreacted monomers and oligomer impurities, and drying, grinding and sieving to obtain the magnesium-iron mineral loaded amphoteric polymer heavy metal adsorbent.
  2. 2. The preparation method of claim 1, wherein the mafic raw ore in the step I is one or more of natural minerals such as pyroxene, olivine and amphibole, the mineral powder is sieved by a sieve of 50-100 meshes, the biochar is one or more of rice hull powder, corn straw and wheat straw, and the biochar is sieved by a sieve of 100-200 meshes.
  3. 3. The method according to claim 1, wherein the calcination activation temperature in step I is 400 ℃ to 600 ℃ for 2h to 3h.
  4. 4. The preparation method of claim 1, wherein the organic solvent in the step II is one or a mixture of more of N, N-dimethylformamide, methanol and ethanol, and the solid-to-liquid ratio of the calcined modified mineral matrix to the organic solvent is 1g (15-25 mL).
  5. 5. The preparation method of claim 1, wherein the amino monomer in the step II is one or more of 4-vinylbenzylamine and dimethylaminoethyl methacrylate, the acrylic monomer is one or more of acrylic acid and itaconic acid, and the mass ratio of the amino monomer to the acrylic monomer is (3-7): 7~3.
  6. 6. The preparation method according to claim 1, wherein the mass ratio of the total mass of the amino monomer and the acrylic monomer in the step II to the calcined modified mineral substrate is (3-6) mmol/1 g.
  7. 7. The method according to claim 1, wherein the crosslinking agent in the step II is ethylene glycol dimethacrylate, and the ratio of the total amount of the amino monomer and the acrylic monomer to the amount of the crosslinking agent is (8-12): 1.
  8. 8. The preparation method according to claim 1, wherein the initiator in the step II is azobisisobutyronitrile, and the mass ratio of the amount of the crosslinking agent to the initiator is 1mmol (60-80) mg.
  9. 9. The preparation method according to claim 1, wherein nitrogen is introduced in step III for 10-15 min, the in-situ radical polymerization reaction is carried out at 65-75 ℃ for 12-18 h.
  10. 10. The preparation method according to claim 1, wherein in the step IV, methanol and deionized water are used for washing 3-5 times respectively, the drying temperature is 80-100 ℃, and the mixture is sieved by a 100-mesh standard sieve.

Description

Preparation method of magnesium-iron mineral loaded amphoteric polymer heavy metal adsorbent Technical Field The invention relates to the technical field of preparation of water treatment functional adsorption materials, in particular to a preparation method of a mineral loaded polymer adsorbent which can be adapted to different pH environments and respectively and efficiently remove cationic or anionic heavy metals. Background With the rapid development of industries such as mining, electroplating, metallurgy, chemical industry and the like, the problem of heavy metal pollution of water bodies is increasingly outstanding. The lead, cadmium, copper and other cationic heavy metals and chromium, arsenic and other heavy metals in the form of oxygen-containing anions have high toxicity, bioaccumulation and carcinogenicity, can be gradually enriched through a food chain, and seriously threatens the ecological safety of water and the health of human bodies. The adsorption method has become one of the mainstream technologies for heavy metal wastewater treatment due to the advantages of simple operation, high treatment efficiency, no secondary pollution and the like. The existing heavy metal adsorbent is mainly divided into two large systems of inorganic minerals and organic polymers, namely the inorganic mineral adsorbent (such as olivine, magnetite and the like) is characterized by large natural reserves, low raw material cost and high mechanical strength, but has the defects of small number of surface functional groups, low adsorption capacity and poor selectivity to heavy metals, and the organic polymer adsorbent can accurately regulate and control the types and density of the functional groups through monomer molecule design, has high adsorption capacity and good selectivity, but the pure polymer material is easy to swell and run in a water body, and has poor mechanical stability and recycling property. More importantly, the existing amine-containing polymer adsorbent can effectively adsorb anionic heavy metals through electrostatic action only under the condition of acidic to neutral (pH=4-7) depending on the protonation of amine groups, and the carboxyl-containing polymer adsorbent can effectively adsorb cationic heavy metals through coordination only under the condition of neutral to weak alkaline (pH=7-9) depending on the deprotonation of carboxyl groups. Because of the difference of the optimal working pH ranges of the two types of functional groups, the single adsorbent is difficult to simultaneously and efficiently remove the anionic and cationic heavy metals under the same pH condition. In actual wastewater treatment, the type of the adsorbent which is adapted is often selected according to the pH characteristics of the wastewater, or the sectional treatment is carried out after the pH is regulated, so that the process complexity and the treatment cost are increased. Therefore, the composite adsorbent which has wide pH application range, can selectively and efficiently remove the corresponding heavy metals according to the pH of the environment and has good mechanical stability is developed, and has important engineering application value. Disclosure of Invention The invention aims to solve the technical problems that the existing adsorbent is difficult to synchronously and efficiently remove negative and positive ion type heavy metals and the pure polymer has poor mechanical stability under the same pH condition, and provides a preparation method of the magnesium-iron-silicon mineral loaded amphoteric polymer heavy metal adsorbent. According to the adsorbent, amino and carboxyl difunctional groups are introduced into the same material, and the pH response characteristic is utilized, so that anionic heavy metals are mainly adsorbed through protonated amino groups in the acidic-neutral range (pH=4-7), and cationic heavy metals are mainly adsorbed through deprotonated carboxyl groups in the neutral-weak alkaline range (pH=7-9), so that heavy metal pollution in a wide pH range is adaptively removed. The preparation method of the magnesium-iron mineral loaded amphoteric polymer heavy metal adsorbent comprises the following steps: I. Mineral matrix pretreatment, namely crushing, grinding and sieving the mafic raw ore to obtain mineral powder, grinding and sieving biochar to obtain biochar, placing the mineral powder into a muffle furnace for calcination and activation, and naturally cooling to obtain a calcined modified mineral matrix; Step II, preparing a precursor dispersion liquid, namely adding a calcined modified mineral matrix into an organic solvent, performing ultrasonic dispersion at room temperature for 20-40 min to obtain a uniform mineral dispersion liquid, sequentially adding an amino monomer, an acrylic monomer, a crosslinking agent and an initiator into the dispersion liquid, and uniformly stirring and mixing to obtain a polymerization precursor liquid; III, in-situ polymerization reaction, n