Search

CN-121988192-A - Pollution-resistant monovalent and divalent ion separation nanofiltration membrane, and preparation and application thereof

CN121988192ACN 121988192 ACN121988192 ACN 121988192ACN-121988192-A

Abstract

The application relates to the technical field of water treatment membrane separation, and particularly discloses a pollution-resistant monovalent and divalent ion separation nanofiltration membrane, and preparation and application thereof. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane comprises a supporting layer, a charge middle layer and a charge separation layer which are sequentially laminated, wherein the charge middle layer is made of polydopamine and/or polyethylenimine, the charge separation layer is made of raw materials comprising an oil phase reactant and a water phase reactant through interfacial polymerization, the oil phase reactant comprises a compound containing acyl halide functional groups, inorganic nano particles are added into the raw materials for preparing the charge separation layer, and the inorganic nano particles comprise graphene oxide two-dimensional lamellar materials, mesoporous silica porous materials and titanium dioxide metal oxides in parts by weight. The application can further improve the pollution resistance of the nanofiltration membrane so as to obtain the pollution-resistant monovalent and divalent ion separation nanofiltration membrane with more excellent and stable divalent salt ion separation effect.

Inventors

  • ZHAO XIAOYANG
  • SONG TAO
  • YE JUNDONG
  • YU JINGHAI

Assignees

  • 重庆海通环保科技有限公司

Dates

Publication Date
20260508
Application Date
20260331

Claims (10)

  1. 1. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane is characterized by comprising a support layer, a charge middle layer and a charge separation layer which are sequentially laminated; the material of the charge interlayer comprises polydopamine and/or polyethyleneimine; the charge separation layer is prepared by interfacial polymerization of raw materials comprising an oil phase reactant and a water phase reactant; the oil phase reactant comprises a compound comprising an acyl halide functional group; Inorganic nano particles are also added into the preparation raw materials of the charge separation layer, and the inorganic nano particles consist of the following components in parts by weight: 5-6 parts of graphene oxide two-dimensional lamellar material; 2.5-3 parts of mesoporous silica porous material; 1.5-2 parts of titanium dioxide metal oxide.
  2. 2. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 1, wherein said graphene oxide two-dimensional platelet material has a lateral diameter of 100-300nm and 1-3 layers; The particle size of the mesoporous silica porous material is 30-50nm, the pore diameter is 3-8nm, and the pore volume is 0.9-1.1cm 3 /g; The primary particle size of the titanium dioxide metal oxide is 10-25nm.
  3. 3. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 1, wherein the inorganic nanoparticles are present in the charged separation layer in a mass ratio of 1-3%.
  4. 4. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 1, wherein the inorganic nanoparticles are prepared by: s1, dispersing a mesoporous silica porous material in absolute ethyl alcohol, performing ultrasonic dispersion, adjusting the pH value, then dropwise adding tetrabutyl titanate in the stirring process, performing a heating reaction, and performing a calcination treatment after centrifugation, washing and drying to obtain an intermediate product; S2, dispersing the intermediate product obtained in the step S1 in absolute ethyl alcohol, adding a silane coupling agent for heating reflux, and obtaining a pretreated intermediate product after the reaction is finished; And S3, dispersing the graphene oxide two-dimensional lamellar material in DMF, adding the pretreated intermediate product obtained in the step S2, adding a condensation activator after ultrasonic mixing, heating, continuously stirring for reaction, centrifuging after the reaction is finished, washing and drying to obtain the inorganic nano particles.
  5. 5. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 4, wherein the calcination temperature is 400-500 ℃ and the calcination time is 1.5-2.5h in step S1.
  6. 6. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 4, wherein in step S3, the stirring reaction temperature is 40-60 ℃, and the stirring reaction time is 20-28 hours.
  7. 7. The monovalent and divalent ion separation nanofiltration membrane of claim 1, wherein the support layer comprises a porous polymer layer and a nonwoven layer laminated in sequence.
  8. 8. The pollution-resistant monovalent and divalent ion separation nanofiltration membrane as recited in claim 1, wherein the charged middle layer is made of polydopamine and polyethylenimine, and the mass ratio of polydopamine to polyethylenimine is 1 (3-4).
  9. 9. The method for preparing the pollution-resistant monovalent and divalent ion separation nanofiltration membrane as claimed in any one of claims 1 to 8, which is characterized by comprising the following steps: (1) Preparing a supporting layer and raw materials required by preparing a charged intermediate layer and a charged separating layer according to a proportion; (2) Immersing the support layer in the step (1) into buffer solution containing polydopamine and/or polyethyleneimine, heating for reaction, washing and drying to form a charged intermediate layer on the surface of the support layer, namely an intermediate product; (3) And (3) sequentially immersing the intermediate product obtained in the step (2) into raw materials of an oil-containing phase reactant and an aqueous phase reactant for reaction, adding inorganic nano particles into the aqueous phase reactant for use, and finally performing heat treatment to obtain the pollution-resistant monovalent and divalent ion separation nanofiltration membrane.
  10. 10. Use of the pollution-resistant monovalent and divalent ion separation nanofiltration membrane according to any one of claims 1 to 8 in brine purification, seawater desalination pretreatment, industrial wastewater advanced treatment and recovery.

Description

Pollution-resistant monovalent and divalent ion separation nanofiltration membrane, and preparation and application thereof Technical Field The application relates to the technical field of water treatment membrane separation, in particular to a pollution-resistant monovalent and divalent ion separation nanofiltration membrane, and preparation and application thereof. Background The nanofiltration membrane is a functional semi-permeable membrane with the aperture of 1-2 nanometers, has the molecular weight cutoff between the reverse osmosis membrane and the ultrafiltration membrane, is an important separation technology, can allow solvent molecules or certain low molecular weight solutes and low valence ions to permeate, has higher entrapment rate on high valence ions, macromolecular organic matters and the like, and is widely applied to a plurality of fields such as water treatment, food medicines, resource recovery and the like. The nanofiltration membrane is of a composite membrane structure, an ultrathin separation layer is formed by polyelectrolyte materials such as polyamide, and the support layer is a porous base membrane. The monovalent and divalent ion selective nanofiltration membranes are novel nanofiltration membranes which can realize high-selectivity separation of specific ions by regulating and controlling the surface charge density and distribution of the membranes while maintaining high water flux, and have the core of showing great potential in the fields of salt lake lithium extraction, wastewater recovery and the like by utilizing the synergistic effect of the Donnan effect and size screening. In the design of monovalent and divalent ion selective nanofiltration membranes, the Zeta potential of the membrane surface is accurately regulated and controlled by introducing a charged intermediate layer or surface grafting, the selectivity of specific ions is enhanced by utilizing electrostatic repulsion/attraction, and a water molecule transmission path can be obviously shortened by constructing an ultrathin and loose polyamide separation layer or adopting a fractal structure substrate, so that higher water flux is obtained under the same pressure, and meanwhile, the high rejection rate of salt is maintained, so that the monovalent and divalent ions are separated with high selectivity. In view of the above related art, the inventors believe that during the separation application, the surface of the polyamide separation layer is prone to adsorb organic pollutants, microorganisms, and the like, which results in membrane pore blocking, flux attenuation, and degradation of separation performance, frequent chemical cleaning is required, and the polyamide separation layer has obvious loss of structural stability during frequent chemical cleaning, which ultimately results in an increase in running cost and a reduction in the service life of the nanofiltration membrane. Therefore, there is a need to propose a solution to the above technical problems. Disclosure of Invention In order to further improve the pollution resistance of the nanofiltration membrane and obtain a better and stable separation effect of divalent salt ions, the application provides a pollution-resistant monovalent and divalent ion separation nanofiltration membrane, and preparation and application thereof. In a first aspect, the application provides a pollution-resistant monovalent and divalent ion separation nanofiltration membrane, which adopts the following technical scheme: a pollution-resistant monovalent and divalent ion separation nanofiltration membrane comprises a support layer, a charge middle layer and a charge separation layer which are sequentially laminated; the material of the charge interlayer comprises polydopamine and/or polyethyleneimine; the charge separation layer is prepared by interfacial polymerization of raw materials comprising an oil phase reactant and a water phase reactant; the oil phase reactant comprises a compound comprising an acyl halide functional group; Inorganic nano particles are also added into the preparation raw materials of the charge separation layer, and the inorganic nano particles consist of the following components in parts by weight: 5-6 parts of graphene oxide two-dimensional lamellar material; 2.5-3 parts of mesoporous silica porous material; 1.5-2 parts of titanium dioxide metal oxide. By adopting the technical scheme, the support layer provides structural strength, the charged intermediate layer and the charged separation layer are prevented from being damaged or deformed under high pressure, the porous structure is provided with a low-resistance transmission path for water molecules, the charged intermediate layer is positively charged or can regulate and control charges, a charge gradient is formed between the charged intermediate layer and the separation layer, the integral Donnan effect is enhanced, the interception selectivity of high-valence ions is improved, the charged sep