阅读说明：本技术 含氟化有机纳米粒子聚酰胺耐溶剂纳滤膜的制备方法 (Preparation method of fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane ) 是由 计艳丽 顾冰心 卢洪浩 高从堦 于 2020-03-03 设计创作，主要内容包括：本发明公开了一种含氟化有机纳米粒子聚酰胺耐溶剂纳滤膜的制备方法,以多元胺、多巴胺以及氟烷基硫醇化合物为反应性单体,通过迈克尔加成和席夫碱反应形成氟化有机纳米粒子,而后与多元酰氯通过界面聚合反应在多孔支撑膜表面形成含氟化有机纳米粒子的聚酰胺膜。利用氟化有机纳米粒子的低表面能特性,调控界面聚合过程,优化聚酰胺分离层的化学组成、微观结构以及亲疏水性,获得具有独特孔道结构的聚酰胺耐溶剂纳滤膜,所制备的膜具有高的分离选择性和溶剂渗透通量,膜制备方法简便、易于调控,具有良好的工业化应用前景。(The invention discloses a preparation method of a fluoride-containing organic nanoparticle polyamide solvent-resistant nanofiltration membrane, which takes polyamine, dopamine and fluoroalkyl mercaptan compounds as reactive monomers, forms fluoride organic nanoparticles through Michael addition and Schiff base reaction, and then forms a polyamide membrane containing fluoride organic nanoparticles on the surface of a porous support membrane through interfacial polymerization reaction with polyacyl chloride. The low surface energy characteristic of fluorinated organic nanoparticles is utilized to regulate and control the interfacial polymerization process, the chemical composition, microstructure and hydrophilicity and hydrophobicity of a polyamide separation layer are optimized, the polyamide solvent-resistant nanofiltration membrane with a unique pore channel structure is obtained, the prepared membrane has high separation selectivity and solvent permeation flux, and the membrane preparation method is simple and convenient, is easy to regulate and control, and has good industrial application prospects.)

1. The preparation method of the fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane is characterized by comprising the following steps of: the method comprises the following steps:

1) dissolving 0.2-5 parts by mass of polyamine monomer molecules and 0.01-0.2 part by mass of dopamine biomimetic adhesive in 100 parts by mass of aqueous solution, then adding 30-50 parts by mass of ethanol solution containing fluoroalkyl thiol compounds into the aqueous solution, introducing oxygen, and reacting at 15-35 ℃ for 1-6 hours to obtain aqueous phase solution containing fluorinated organic nanoparticles;

2) soaking the porous support membrane in the aqueous phase solution containing the fluorinated organic nanoparticles for 1-30 minutes, taking out and removing the excessive aqueous phase solution on the surface of the membrane; then immersing the membrane into an organic phase solution containing polybasic acyl chloride monomer molecules for interfacial polymerization for 0.5-5 minutes, and taking out and removing the residual organic phase solution on the surface of the membrane; carrying out heat treatment at 30-80 ℃ for 5-30 minutes to obtain a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane;

wherein, the polyamine monomer molecule in the step 1) is one of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, piperazine or 1,3, 5-triaminobenzene; the fluoroalkyl mercaptan compound in the step 1) is one of pentafluoro pentane mercaptan, 1H,2H, 2H-perfluorohexane mercaptan, 1H,2H, 2H-perfluorooctanethiol, 1H,2H, 2H-perfluorodecanethiol or 1H,1H,2H, 2H-perfluorododecanethiol; the polyacyl chloride monomer in the step 2) is one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride or biphenyl tetracarboxyl chloride.

2. The method of claim 1, wherein: the mass percentage concentration of the fluoroalkyl thiol compound in the ethanol solution containing the fluoroalkyl thiol compound in the step 1) is 0.01-0.1%.

3. The method of claim 1, wherein: the ethanol solution in the step 1) is an ethanol solution with the mass percentage concentration of 90-98%.

4. The method of claim 1, wherein: the porous support membrane in the step 2) is one of polyethersulfone, polyacrylonitrile, polyvinylidene fluoride or polyimide flat ultrafiltration membranes.

5. The method of claim 1, wherein: the mass percentage concentration of the polybasic acyl chloride monomer in the organic phase solution in the step 2) is 0.05-0.5%.

6. The method of claim 1, wherein: the solvent of the organic phase solution in the step 2) is one of normal hexane, cyclohexane or heptane.

Technical Field

The invention belongs to the field of membrane separation, and particularly relates to a preparation method of a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane.

Background

The membrane separation technology is a new technology which takes a separation membrane as a core and carries out separation, concentration and purification of substances, and is rapidly developed from the 60 s in the 20 th century. For pressure driven membrane separation processes, microfiltration, ultrafiltration, nanofiltration and reverse osmosis can be classified according to the size of the membrane pores, the operating pressure and the size of the molecular weight cut-off. At present, most modern industrialized products such as petroleum, fine chemicals, food, biological medicine and other substances are generally required to be separated and purified in an organic solvent-containing system, and solvent-resistant nanofiltration is gradually developed into one of effective methods in the process of seeking sustainable and efficient separation. Solvent-resistant nanofiltration is a novel membrane separation technology which is green, efficient and energy-saving, can realize the purification and the recycling of a solvent in an organic solvent system, and can effectively separate solutes with the molecular weight of 200-2000 Da. The solvent-resistant nanofiltration has attracted the interest of more and more researchers, and has wide application prospect in the industries of food, medicine, chemical industry and the like.

The separation membrane is the core of the development of membrane technology, and the preparation of the solvent-resistant nanofiltration membrane with high osmotic selectivity and good stability still faces huge challenges. Conventional polymer membranes typically suffer from permeability and selectivity "Trade-off", which greatly limits the improvement in membrane separation performance. Particularly in an organic solvent system, polymer molecular chains are easy to swell, compact and the like, so that the performance of the membrane is reduced. Therefore, in order to meet the complex and severe requirements of practical application systems, it is necessary to develop a high-performance solvent-resistant nanofiltration membrane and to form a membrane by a simple and controllable method. Recently, the introduction of nano materials into polyamide membranes to construct polyamide nanocomposite membranes with biomimetic "water channel" structures has become a research hotspot for preparing high-performance nanofiltration membranes. Has now beenThere are a large number of reports of inorganic nanomaterials such as zeolite molecular sieves, metal oxides (TiO)₂) graphene/Graphene Oxide (GO), Carbon Nanotubes (CNT) and the like are introduced into the polyamide membrane, and the osmotic selectivity and the structural stability of the polyamide membrane can be improved by utilizing the interface gap between the inorganic nano material and the polymer and the inherent characteristics (pore channel structure, charge property, hydrophilicity and hydrophobicity and the like) of the nano material. However, due to the characteristics of the inorganic nano material and the compatibility problem between the inorganic nano material and the polyamide-based membrane, the membrane is prone to generate non-selective defects, so that the membrane structure is unstable, and the separation performance of the membrane is affected. In order to solve the problems, the development of a novel nano material and the development of a high-performance solvent-resistant polyamide mixed matrix nanofiltration membrane are very important.

Recently, fluorine-containing organic compounds have been gradually used for the preparation of separation membranes. The fluorine-containing material has lower surface energy, and the introduction of the fluorine-containing material into the membrane can reduce the interaction between the membrane and pollutants and effectively enhance the anti-pollution property of the membrane; in addition, the fluorine-containing material has hydrophobic groups, and the introduction of the hydrophobic groups into the hydrophilic polyamide membrane can effectively regulate and control the hydrophilicity and hydrophobicity of the membrane, so that a high-performance solvent-resistant nanofiltration membrane is expected to be obtained. In recent years, polydopamine has attracted great interest to researchers as a functional material widely used for membrane surface modification. Besides good adhesion performance, the active functional group contained in the polydopamine can react with thiol and amino compounds through Michael addition or Schiff base reaction, so that the polydopamine is an ideal material for surface engineering.

In summary, the present invention provides a method for synthesizing fluorinated organic nanoparticles by using polyamine monomer molecules, dopamine biomimetic adhesive and fluoroalkyl thiol compound as reactive monomers through michael addition and schiff base reaction in ethanol aqueous solution, and then forming a polyamide layer containing fluorinated organic nanoparticles on the surface of a porous support membrane through interfacial polymerization with polyacyl chloride. By utilizing the low surface energy characteristic and the hydrophobicity of the fluorinated organic nanoparticles, a unique pore channel structure can be constructed in the polyamide layer, and the obtained membrane is endowed with excellent anti-pollution performance; in addition, the strong adhesion stability of dopamine is combined, so that the membrane has excellent structural stability while high osmotic selectivity and strong pollution resistance are maintained, and the requirement of practical application can be better met.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane.

The preparation method of the fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane is characterized by comprising the following steps of: the method comprises the following steps:

1) dissolving 0.2-5 parts by mass of polyamine monomer molecules and 0.01-0.2 part by mass of dopamine biomimetic adhesive in 100 parts by mass of aqueous solution, then adding 30-50 parts by mass of ethanol solution containing fluoroalkyl thiol compounds into the aqueous solution, introducing oxygen, and reacting at 15-35 ℃ for 1-6 hours to obtain aqueous phase solution containing fluorinated organic nanoparticles;

2) soaking the porous support membrane in the aqueous phase solution containing the fluorinated organic nanoparticles for 1-30 minutes, taking out and removing the excessive aqueous phase solution on the surface of the membrane; then immersing the membrane into an organic phase solution containing polybasic acyl chloride monomer molecules for interfacial polymerization for 0.5-5 minutes, and taking out and removing the residual organic phase solution on the surface of the membrane; carrying out heat treatment at 30-80 ℃ for 5-30 minutes to obtain a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane;

wherein, the polyamine monomer molecule in the step 1) is one of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, piperazine or 1,3, 5-triaminobenzene; the fluoroalkyl mercaptan compound in the step 1) is one of pentafluoro pentane mercaptan, 1H,2H, 2H-perfluorohexane mercaptan, 1H,2H, 2H-perfluorooctanethiol, 1H,2H, 2H-perfluorodecanethiol or 1H,1H,2H, 2H-perfluorododecanethiol; the polybasic acyl chloride monomer in the step 2) is one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride or biphenyl tetracarboxyl chloride;

the mass percentage concentration of the fluoroalkyl thiol compound in the ethanol solution containing the fluoroalkyl thiol compound in the step 1) is 0.01-0.1%; the ethanol solution in the step 1) is an ethanol solution with the mass percentage concentration of 90-98%; the porous support membrane in the step 2) is one of polyether sulfone, polyacrylonitrile, polyvinylidene fluoride or polyimide flat ultrafiltration membrane; the mass percentage concentration of the polybasic acyl chloride monomer in the organic phase solution in the step 2) is 0.05-0.5%; the solvent of the organic phase solution in the step 2) is one of normal hexane, cyclohexane or heptane.

The fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane can be used in the field of separation of organic molecules in solvents with different polarities.

The invention discloses a performance evaluation method of a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane, which comprises the following steps: placing a nanofiltration membrane in a solvent-resistant nanofiltration performance evaluation device, soaking the nanofiltration membrane in a tested solvent for 10min before testing, prepressing the nanofiltration membrane for 1h under the operation pressure of 2.0MPa, and then measuring the solvent permeation flux (J) and the organic matter molecule rejection rate (R) of the membrane under the test conditions of 25 ℃ and 1.5MPa, wherein the calculation formula is as follows: j ═ V/(A.t); r is 1-Cp/Cf; wherein the volume of the V-permeate and the effective area of the A-membrane are 19.625cm²T-run time, Cp-permeate concentration, Cf-feed concentration; the concentration of the organic matter solution can be obtained by measuring the ultraviolet absorbance of the solution.

The fluorinated organic nanoparticles are synthesized by reacting polyamine monomer molecules, a dopamine bionic adhesive and a fluoroalkyl thiol compound through Michael addition and Schiff base, the chemical composition, the particle structure and the hydrophilicity and hydrophobicity of the fluorinated organic nanoparticles are easy to adjust, the polyamide solvent-resistant nanofiltration membrane with a loose upper surface, hydrophilicity and a compact and hydrophobic lower surface and a unique channel structure can be obtained by introducing the fluorinated organic nanoparticles to regulate the interfacial polymerization process, the flux of the nanofiltration membrane to a strong polar solvent is 60-90L, M^-2.h^-1Flux to less polar solvents is typically less than 30L. M^-2.h^-1The molecular interception rate of the organic dye with molecular weight higher than 300Da can reach up to 99 percent. The fluorinated organic nanoparticles contain C-F groups, have low surface energy and hydrophobicity, so that the polyamide separation layer has a unique pore channel structure and excellent stain resistance; at the same time, the user can select the desired position,the nano particles contain a large amount of active groups (sulfydryl) and strong adhesion dopamine, so that stable chemical bonds can be formed between the particles and polyamide polymer chains and between the particles and the porous support membrane, and the membrane has high osmotic selectivity and excellent structural stability. In addition, the membrane preparation method is simple and easy to control, and has good industrial application prospect.

Drawings

Fig. 1 is a surface topography (a) and a cross-section topography (b) of the fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane of the present invention.

Detailed Description

The preparation method of the fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane comprises the following steps:

1) dissolving 0.2-5 parts by mass of polyamine monomer molecules and 0.01-0.2 part by mass of dopamine biomimetic adhesive in 100 parts by mass of aqueous solution, then adding 30-50 parts by mass of ethanol solution containing fluoroalkyl thiol compounds into the aqueous solution, introducing oxygen, and reacting at 15-35 ℃ for 1-6 hours to obtain aqueous phase solution containing fluorinated organic nanoparticles;

2) soaking the porous support membrane in the aqueous phase solution containing the fluorinated organic nanoparticles for 1-30 minutes, taking out and removing the excessive aqueous phase solution on the surface of the membrane; then immersing the membrane into an organic phase solution containing polybasic acyl chloride monomer molecules for interfacial polymerization for 0.5-5 minutes, and taking out and removing the residual organic phase solution on the surface of the membrane; carrying out heat treatment at 30-80 ℃ for 5-30 minutes to obtain a fluorinated organic nanoparticle-containing polyamide solvent-resistant nanofiltration membrane; wherein, the polyamine monomer molecule in the step 1) is one of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, piperazine or 1,3, 5-triaminobenzene; the fluoroalkyl mercaptan compound in the step 1) is one of pentafluoro pentane mercaptan, 1H,2H, 2H-perfluorohexane mercaptan, 1H,2H, 2H-perfluorooctanethiol, 1H,2H, 2H-perfluorodecanethiol or 1H,1H,2H, 2H-perfluorododecanethiol; the polybasic acyl chloride monomer in the step 2) is one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride or biphenyl tetracarboxyl chloride; the mass percentage concentration of the fluoroalkyl thiol compound in the ethanol solution containing the fluoroalkyl thiol compound in the step 1) is 0.01-0.1%; the ethanol solution in the step 1) is an ethanol solution with the mass percentage concentration of 90-98%; the porous support membrane in the step 2) is one of polyether sulfone, polyacrylonitrile, polyvinylidene fluoride or polyimide flat ultrafiltration membrane; the mass percentage concentration of the polybasic acyl chloride monomer in the organic phase solution in the step 2) is 0.05-0.5%; the solvent of the organic phase solution in the step 2) is one of normal hexane, cyclohexane or heptane.

Examples of the present invention are given below, but the present invention is not limited by the examples: