CN113289505B - Preparation method of polyether-containing amphiphilic polymer/PVDF (polyvinylidene fluoride) blend membrane - Google Patents

Preparation method of polyether-containing amphiphilic polymer/PVDF (polyvinylidene fluoride) blend membrane Download PDF

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CN113289505B
CN113289505B CN202110695547.8A CN202110695547A CN113289505B CN 113289505 B CN113289505 B CN 113289505B CN 202110695547 A CN202110695547 A CN 202110695547A CN 113289505 B CN113289505 B CN 113289505B
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polyether
membrane
pvdf
amphiphilic polymer
sma
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CN113289505A (en
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张萌萌
严峰
王明霞
庄圆
王峥
易宏
张达
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Tianjin Polytechnic University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/52—Polyethers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0006—Organic membrane manufacture by chemical reactions
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/40—Devices for separating or removing fatty or oily substances or similar floating material
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/36—Hydrophilic membranes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities

Abstract

The invention provides a preparation method of a polyether-containing amphiphilic polymer/PVDF (polyvinylidene fluoride) blend membrane. Specifically, firstly, grafting amine-terminated polyether onto polystyrene/maleic anhydride (SMA) to prepare a polyether-grafted SMA amphiphilic polymer; and then blending the polyether grafted SMA amphiphilic polymer and polyvinylidene fluoride (PVDF) to prepare a membrane casting solution, and preparing the polyether grafted SMA amphiphilic polymer/PVDF blended membrane by adopting a non-solvent phase-induced inversion method. The surface and pore walls of the membrane have polyether groups, so that the membrane has good hydrophilicity and underwater super-oleophobic property, and meanwhile, the polyether on the surface of the membrane has a demulsification function, so that the membrane can be used for demulsification and oil-water separation of oil production sewage.

Description

Preparation method of polyether-containing amphiphilic polymer/PVDF (polyvinylidene fluoride) blend membrane
Technical Field
The invention belongs to the technical field of functional polymer membrane separation, and particularly relates to a preparation method of a polyether-containing amphiphilic polymer/PVDF (polyvinylidene fluoride) blend membrane.
Background
With the rapid development of petrochemical, pharmaceutical, metallurgical and food processing industries, a large amount of oily sewage is generated, which poses great challenges to human life and natural environment. Wherein, the water content of the petroleum produced liquid in China is higher and higher, and the water content of part of the oil field produced liquid exceeds 95%, which brings great challenge to the treatment of oil extraction sewage and even influences the normal production of the oil field.
Because the mining oil wastewater has high mineralization, the mining oil wastewater usually contains oil displacement agents such as active agents, polymers and the like and crude oil with certain concentration to form an oil-in-water emulsion. Conventional methods for treating oil recovery wastewater include gravity precipitation, adsorption, chemical methods, and the like. The gravity precipitation method is used for treating oil extraction sewage by utilizing the principle that oil and water are mutually incompatible. The method needs long settling time and large equipment. The adsorption method is to use an adsorbent (oleophilic material) to adsorb oil in sewage to realize oil-water separation, and the treatment and regeneration of the adsorbent are the main problems faced by the adsorption method at present. The chemical law is the most important and mature method for treating oil extraction sewage, and the used chemical agents are mainly reverse demulsifier and flocculant. Reverse demulsifiers are typically positively charged polymeric activators that can break the oil-in-water emulsion by electrically neutralizing the oil-water interfacial film and further separate the oil (actually floe) from water under the action of flocculants (polyaluminum chloride, polyferric chloride, etc.). Although the reverse demulsification and flocculation technology can thoroughly remove suspended matters and emulsified oil in the oil production wastewater, the practical effect of the reverse demulsification and flocculation technology is not satisfactory in recent years. This is because the oil recovery wastewater contains suspended matter, emulsified oil, and residual flooding polymer (partially hydrolyzed polyacrylamide, HPAM). The polymer-containing oil sludge is negatively charged, and after the polymer-containing oil sludge reacts with the cation reverse demulsifier and the flocculant, the polymer-containing oil sludge is wrapped and carried with crude oil to deposit on the bottom of an oil extraction wastewater treatment tank or cause the blockage of pipelines and filters. Not only the normal production of the oil field is influenced, but also the large amount of polymer-containing oil sludge removed from the tank bottom and the pipelines causes environmental pollution.
Membrane separation is a new technology of separation that rises rapidly after the 60's of the 20 th century. The membrane separation is a physical process, and has the advantages of low energy consumption, high separation efficiency, simple process and the like, so the membrane separation is introduced into the field of oil-water separation in recent years. For example, the chinese invention CN 10269871A discloses that a porous membrane is prepared by using polylactic acid, and then the porous membrane is modified to obtain a degradable oil-water separation membrane with hydrophobic property, although the material shows stronger hydrophobic property, the material has low pressure bearing capacity due to the poor mechanical property of the polymer, and the application of the material is limited. The patent CN103961905A discloses a preparation method of a super-hydrophobic oleophilic oil-water separation net film with low cost and high oil-water separation efficiency. According to the invention, inorganic matters with low cost are used as partial raw materials, a mild preparation process is adopted, a nano-scale mastoid structure is formed on a metal net by a sol method, and the constructed nano-silica is modified by using a low-energy organic modifier to prepare the super-hydrophobic oleophilic oil-water separation net film. CN109316981B discloses a preparation method of a super-hydrophilic polymer membrane with a demulsification function. Polyvinylidene fluoride (PVDF), polypropylene (PP) or Polytetrafluoroethylene (PTFE) are used as base membrane materials to be blended with styrene-maleic anhydride copolymer (SMA) to prepare membrane casting solution, a non-solvent induced phase inversion method is adopted to prepare a PVDF/SMA ultrafiltration membrane, and a hyperbranched polyether demulsifier is grafted to a polymer membrane by utilizing chemical reaction between anhydride of the membrane and hydroxyl at the end of the hyperbranched polyether demulsifier. In addition, the low permeation flux and poor antigen oil pollution are the bottlenecks of the current membrane separation technology in the industrial treatment of the oily sewage.
As is well known, polyether substances can be generally used as demulsifiers of petroleum produced fluids, and polyether chain segments can be adsorbed on an oil-water interface to destroy the stability of an interfacial film of an emulsion so as to demulsify the emulsion.
Based on the research, the invention combines a chemical demulsification method with a membrane separation technology. Firstly, grafting amine-terminated polyether onto polystyrene/maleic anhydride (SMA) to prepare a polyether grafted SMA amphiphilic polymer; and then blending the polyether grafted SMA amphiphilic polymer and polyvinylidene fluoride (PVDF) to prepare a membrane casting solution, and preparing the polyether grafted SMA amphiphilic polymer/PVDF blended membrane by adopting a non-solvent phase-induced inversion method. The polyether is grafted with SMA with high molecular weight through amido bond and then is blended with PVDF, so that the polyether on the surface of the membrane can be ensured to keep chemical stability under the harsh condition of oil extraction wastewater. The surface and the pore wall of the membrane have polyether groups, so that the membrane has good hydrophilicity and underwater super-oleophobic property, and meanwhile, the polyether on the surface of the membrane has a demulsification function, so that the membrane can be used for demulsification and oil-water separation of oil production sewage.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a preparation method of a polyether-containing amphiphilic polymer/PVDF blended membrane.
The invention relates to a preparation method of a polyether-containing amphiphilic polymer/PVDF blend membrane, which comprises the following steps: (1) Dissolving amine-terminated polyether with certain mass in an organic solvent, and stirring at 40-90 ℃; slowly dripping SMA dissolved in an organic solvent into an excessive amine-terminated polyether solution, and stirring and reacting for 1-10 h at 40-90 ℃; (2) After the reaction is finished, pouring the reaction solution into ethanol, acetone or water to separate out the polymer, and washing the separated polymer for multiple times by using ethanol to remove unreacted raw materials to obtain the polyether grafted SMA amphiphilic polymer; (3) Polyether grafted SMA amphiphilic polymer and PVDF are mixed, dissolved in an organic solvent at 60-90 ℃ to prepare a casting solution with a certain concentration, defoamed, poured onto a glass plate to be scraped into a liquid film, and transferred into a coagulating bath to prepare the polyether-containing amphiphilic polymer/PVDF blended film by a non-solvent phase-induced inversion method. Wherein, the SMA molecular weight is between 3000 and 100000Da, and the content of acid anhydride is less than or equal to 20 percent; the amine-terminated polyether comprises monoamino substituted polyether or polyamino substituted polyether, the polyether can be straight chain or branched chain polyoxybutylene ether, polyoxypropylene ether, polyoxyethylene ether or block polyether, and the molecular weight range of the amine-terminated polyether is 200-10000; the organic solvent is one of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide. The viscosity control range of the casting film liquid is 500-2500 mPa.s, the amphiphilic polyether grafted SMA polymer accounts for 2-16% of the total mass of the casting film liquid, and the PVDF accounts for 8-18% of the total mass of the casting film liquid. The coagulating bath is one or more of water, ethanol, methanol, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
The polyether-containing amphiphilic polymer/PVDF blended membrane has excellent hydrophilic and underwater super-oleophobic properties, the contact angle of pure water of the membrane is less than 50 degrees, and the contact angle of underwater oil is more than 140 degrees.
The polyether-containing amphiphilic polymer/PVDF blend membrane has excellent oil-water separation property, and the oil-water separation rate of oil extraction sewage is more than 98%.
Detailed Description
The following examples are presented to enable those skilled in the art to more fully understand the present invention and are not intended to limit the invention in any way.
Example 1
(1) 10g of polyetheramine D230 was dissolved in 10g of N, N-dimethylformamide, and 5g of SMA (molecular weight: 5000, acid anhydride content: 10%) was dissolved in 15g of N, N-dimethylformamide; slowly dripping the SMA solution into the D230 solution, and stirring and reacting for 10 hours at 60 ℃;
(2) After the reaction is finished, pouring the reaction solution into ethanol to precipitate a polymer, and washing the precipitated polymer for multiple times by using the ethanol to remove unreacted raw materials to obtain the D230 grafted SMA amphiphilic polymer, namely D230-g-SMA;
(3) Dissolving 2g of D230-g-SMA amphiphilic polymer and 6g of PVDF in 42g of N, N-dimethylformamide at 70 ℃ to prepare a membrane casting solution, defoaming the membrane casting solution, pouring the membrane casting solution on a glass plate to scrape the membrane casting solution into a liquid membrane, and transferring the liquid membrane into water to prepare a D230-g-SMA/PVDF blend membrane by a non-solvent phase-induced transformation method;
(4) D230-g-SMA/PVDF blended membrane has a pure water contact angle of 50 degrees, an underwater oil (kerosene) contact angle of 144 degrees and a pure water flux of 350 L.m under 0.1MPa -2 ·h -1 (ii) a After the oil extraction wastewater with the mineralization degree of 5032mg/L and the oil content of 135mg/L is treated by the D230-g-SMA/PVDF blended membrane, the removal rate of crude oil in water reaches 98.4 percent.
Example 2
(1) 10g of polyetheramine CAED600 was dissolved in 10g of N, N-dimethylacetamide, and 5g of SMA (molecular weight 20000, acid anhydride content 10%) was dissolved in 15g of N, N-dimethylacetamide; slowly dropwise adding the SMA solution into the CAED600 solution, and stirring and reacting for 10 hours at 60 ℃;
(2) After the reaction is finished, pouring the reaction solution into ethanol to precipitate a polymer, and washing the precipitated polymer for multiple times by using the ethanol to remove unreacted raw materials to obtain a CAED600 grafted SMA amphiphilic polymer, namely CAED600-g-SMA for short;
(3) Dissolving 4g CAED600 amphiphilic polymer and 7g PVDF in 39g N, N-dimethylacetamide at 70 ℃ to prepare a casting solution, pouring the casting solution on a glass plate to scrape the casting solution into a liquid film after defoaming, and then transferring the liquid film into ethanol to prepare a CAED600-g-SMA/PVDF blended film by a non-solvent phase-induced inversion method;
(4) The pure water contact angle of the CAED600-g-SMA/PVDF blended membrane is 43 degrees, the underwater oil (kerosene) contact angle is 151 degrees, and the pure water flux is 280 L.m under 0.1MPa -2 ·h -1 (ii) a After the oil extraction wastewater with the mineralization degree of 5032mg/L and the oil content of 135mg/L is treated by a CAED600-g-SMA/PVDF blended membrane, water is obtainedThe removal rate of medium crude oil reaches 98.8 percent.
Example 3
(1) 10g of polyetheramine T403 was dissolved in 10g of N, N-dimethylformamide, and 5g of SMA (molecular weight: 50000, acid anhydride content: 12%) was dissolved in 15g of N, N-dimethylformamide; slowly dropwise adding the SMA solution into the T403 solution, and stirring and reacting for 10 hours at 60 ℃;
(2) After the reaction is finished, pouring the reaction solution into ethanol to precipitate a polymer, and washing the precipitated polymer for multiple times by using the ethanol to remove unreacted raw materials to obtain the T403 grafted SMA amphiphilic polymer, namely T403-g-SMA for short;
(3) Dissolving 3g of T403-g-SMA and 6g of PVDF in 41g of N, N-dimethylformamide at 70 ℃ to prepare a casting solution, defoaming, pouring the casting solution on a glass plate, scraping the casting solution to prepare a liquid membrane, and transferring the liquid membrane into water to prepare a T403-g-SMA/PVDF blended membrane by a non-solvent phase-induced inversion method;
(4) The pure water contact angle of the T403-g-SMA/PVDF blended membrane is 48 degrees, the underwater oil (kerosene) contact angle is 150 degrees, and the pure water flux is 360 L.m under 0.1MPa -2 ·h -1 (ii) a After the oil extraction wastewater with the mineralization degree of 6352mg/L and the oil content of 200mg/L is treated by the T403-g-SMA/PVDF blend membrane, the removal rate of crude oil in water reaches 99.5 percent.

Claims (3)

1. A preparation method of a polyether-containing amphiphilic polymer/PVDF blended membrane is characterized by comprising the following steps: (1) Dissolving amine-terminated polyether with certain mass in an organic solvent, and stirring at 40-90 ℃; slowly dripping polystyrene/maleic anhydride (SMA) dissolved in an organic solvent into an excessive amine-terminated polyether solution, and stirring and reacting for 1-10 h at 40-90 ℃; (2) After the reaction is finished, pouring the reaction solution into ethanol, acetone or water to separate out the polymer, and washing the separated polymer with ethanol for multiple times to remove unreacted raw materials to obtain the polyether grafted SMA amphiphilic polymer; (3) Blending polyether grafted SMA amphiphilic polymer and PVDF, dissolving in an organic solvent at 60-90 ℃, preparing a casting solution with a certain concentration, defoaming, pouring onto a glass plate, scraping to form a liquid film, transferring into a coagulating bath, and preparing the polyether grafted SMA amphiphilic polymer/PVDF blended film by a non-solvent phase-induced inversion method;
the SMA molecular weight is between 3000 and 100000Da, and the content of acid anhydride is less than or equal to 20 percent;
the amine-terminated polyether comprises monoamino substituted polyether or polyamino substituted polyether, the polyether can be straight chain or branched chain polyoxybutylene ether, polyoxypropylene ether, polyoxyethylene ether or block polyether, and the molecular weight range of the amine-terminated polyether is 200-10000;
the organic solvent is one of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide;
the viscosity control range of the casting film liquid is 500-2500 mPa.s, the polyether grafted SMA amphiphilic polymer accounts for 2-16% of the total mass of the casting film liquid, and the PVDF accounts for 8-18% of the total mass of the casting film liquid;
the coagulating bath is one or more of water, ethanol, methanol, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
2. The method for preparing the polyether-containing amphiphilic polymer/PVDF blend membrane as claimed in claim 1, wherein the polyether-containing amphiphilic polymer/PVDF blend membrane has excellent hydrophilic and underwater superoleophobic properties, the contact angle of pure water of the membrane is less than 50 degrees, and the contact angle of underwater oil is greater than 140 degrees.
3. The method for preparing the polyether-containing amphiphilic polymer/PVDF blend membrane as claimed in claim 1, wherein the polyether-containing amphiphilic polymer/PVDF blend membrane has excellent oil-water separation property, and the oil-water separation rate of oil-extraction wastewater is greater than 98%.
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CN115368577B (en) * 2022-07-15 2023-05-23 天津工业大学 Hyperbranched polyether grafted polystyrene maleic anhydride oil-water synchronous demulsification water-cleaning agent

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CN110833774A (en) * 2019-12-05 2020-02-25 淮安晶彩新材料科技有限公司 Preparation method of demulsifier functionalized oil-water separation membrane

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