CN103736405A - Preparation method of cation exchange membrane with function of selectively separating monovalent and multivalent cations - Google Patents

Abstract

The invention discloses a preparation method of a cation exchange membrane with a function of selectively separating monovalent and multivalent cations. The preparation method is characterized in that by taking an acidic polymer and an alkaline monomer as raw materials, acidic ion exchange groups of the acidic polymer are partially or completely acid-base paired to obtain the cation exchange membrane with the function of selectively separating monovalent and multivalent cations. According to the preparation method disclosed by the invention, the acid-base pair effect can be formed between the acidic polymer and the alkaline monomer, so that the acidic ion exchange groups of the acidic polymer are partially or completely acid-base paired so as to construct a channel, which just can be used for transferring protons, in the membrane, and the monovalent and multivalent cations are separated.

Description

A kind of preparation method with the cation-exchange membrane of a polyvalent cation Selective Separation function

Technical field

The invention belongs to amberplex technical field, particularly be a kind of preparation method with the cation-exchange membrane of a polyvalent cation Selective Separation function.

Background technology

Along with the application of amberplex constantly expands, the demand of reality proposes requirements at the higher level to the Selective Separation performance of film.Particularly for the separation of the mixed solution that contains identical charges different valence state ion, for example, the integrated application of wastewater treatment, hydrometallurgy, seawater etc.

Preparation about a polyvalent cation selective diffusion barrier at present focuses mostly in the surface modification to business amberplex.Taylor & Francis periodical Desalination and Water Treatment (2013,51,2740-2748) introduced and a kind ofly by infusion method, at the polymer of adsorption one deck lotus positive electricity of cation-exchange membrane, prepared univalent cation selective diffusion barrier.To H ⁺, Zn ²⁺, Na ⁺, Mg ²⁺experimental result etc. system separation shows, Modified Membrane is to a polyvalent cation Selective Separation successful.Yet by this method the Modified Membrane of preparation have a fatal defect be exactly the life-span short, while using for a long time, surface reforming layer easily comes off, separating property declines.

The Journal of Materials Chemistry of Britain imperial familyization institute periodical (2010,20,3750-3757) reported that method by " the grappling process of diazonium induction " is in business cation-exchange membrane surface chemistry grafting last layer polyaniline shape modified layer, and for H ⁺, Zn ²⁺the separation of system, shows good Selective Separation effect.Yet this method of modifying is not suitable for large area preparation, and equipment requirement is higher, and cost is high, and the thickness of modified layer is difficult to control.

The problems such as synthesize the relevant data visible, the preparation of current univalent cation selective diffusion barrier exists preparation process poor controllability, and extensive industrialization difficulty and service life are short.

Summary of the invention

For avoiding the existing weak point of above-mentioned prior art, the invention provides a kind of preparation method simple, have extensive industrialization prospect, select separating property significantly, the preparation method of the cation-exchange membrane with a polyvalent cation Selective Separation function of long service life.

Technical solution problem of the present invention, adopts following technical scheme:

The invention discloses a kind of preparation method with the cation-exchange membrane of a polyvalent cation Selective Separation function, its feature is: take acidic polymer and alkaline monomer is raw material, make partly or completely " acid-base pair " change of acid ion cation exchange groups of acidic polymer, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

The present invention has the preparation method of the cation-exchange membrane of a polyvalent cation Selective Separation function, and its feature is: described acidic polymer is sulfonated poly (phenylene oxide); Described alkaline monomer is polyvinyl imidazol.

Described preparation method carries out as follows:

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.06-0.6g vinyl imidazole, stir 24h, and then add 0.002-0.02g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Described uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

The present invention can form the principle of " acid-base pair " under certain condition according to acidic polymer and alkaline polymer, makes partly or completely " acid-base pair " change of acid ion cation exchange groups of acidic polymer." acid-base pair " changes ion-exchange group still can realize the transmission of proton, but can not transmit metal ion, thereby realize the separation of a polyvalent cation.

Described sulfonated poly (phenylene oxide) is by containing sulfonic repetitive and not forming containing sulfonic repetitive, and two kinds of shared ratios of repetitive are respectively 28% and 72%, and its structural formula is:

Polyvinyl imidazol is formed by the radical polymerization under described experiment condition of added monomer vinyl imidazoles, and its structural formula is:

Compared with prior art, beneficial effect of the present invention is embodied in:

(1) the present invention utilizes the effect that can form " acid-base pair " between acidic polymer and alkaline monomer, make partly or completely " acid-base pair " change of acid ion cation exchange groups, thereby in film, constructed a passage that can only transmit proton, realized the separation of a polyvalent cation.

(2) the present invention is different from traditional method that improves a multivalent ion separating property of film by process for modifying surface completely, problem with regard to having avoided surface reforming layer to come off in long-term use procedure like this, extended the service life of film, also avoided surface reforming layer to be difficult to the shortcoming of accurately controlling simultaneously, preparation technology is simplified greatly, for suitability for industrialized production provides possibility.Accompanying drawing explanation

Fig. 1 is electrodialysis plant, and wherein, AEM is anion-exchange membrane; CEM is cation-exchange membrane;

Fig. 2 is the infrared spectrum that different " acid-base pair " changes degree film;

Fig. 3 is " acid-base pair " film transmission proton schematic diagram.

The specific embodiment

Below in conjunction with accompanying drawing and by specific embodiment, further describe the present invention.

Embodiment 1

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.06g vinyl imidazole, stir 24h, and then add 0.002g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

With H ⁺/ Zn ²⁺system is simulated hydrometallurgy application, and electrodialytic process as shown in Figure 1.

Wherein diluting compartment is 0.23M ZnSO ₄with 0.5M H ₂sO ₄mixed liquor, enriched chamber is 0.05M H ₂sO ₄, utmost point chamber is 0.1M Na ₂sO ₄.In experiment, current density is 35mA/cm ², the electrodialysis time is 60min.With zinc ion slip, weigh the film performance separated to a polyvalent cation with selection permeability, it should be noted that, these two desired values are less, and the selection separating property of film is better.Its computational methods are:

Zinc ion slip:

Select permeability: $P_{H^{+}}^{{\mathrm{<figure-callout\; id="2"\; label="Zn"\; filenames="HDA0000440086760000011.png"\; state="\{\{state\}\}">Zn</figure-callout>}}^{2+}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="t\; Zn"\; filenames="HDA0000440086760000011.png"\; state="\{\{state\}\}">t</figure-callout>}}_{{\mathrm{Zn}}^{}}/2{\mathrm{<figure-callout\; id="2"\; label="C\; Zn"\; filenames="HDA0000440086760000011.png"\; state="\{\{state\}\}">C</figure-callout>}}_{{\mathrm{Zn}}^{}}}{t_{H^{+}}/C_{H^{+}}}.$

Electrodialysis experimental result shows, more " acid-base pair " changes sulfonated poly (phenylene oxide) film, and zinc ion slip reduces to 2.6% by 7.3%, selects permeability to reduce to 0.16 by 0.49.

Embodiment 2

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.19g vinyl imidazole, stir 24h, and then add 0.006g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

Electrodialysis experiment condition is with embodiment 1, and diluting compartment is 0.23M ZnSO ₄with 0.5M H ₂sO ₄mixed liquor, enriched chamber is 0.05M H ₂sO ₄, utmost point chamber is 0.1M Na ₂sO ₄.In experiment, current density is 35mA/cm ², the electrodialysis time is 60min.Electrodialysis experimental result shows, more " acid-base pair " changes sulfonated poly (phenylene oxide) film, and zinc ion slip reduces to 0.08% by 7.3%, selects permeability to reduce to 0.004 by 0.49.

Embodiment 3

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.3g vinyl imidazole, stir 24h, and then add 0.01g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

Electrodialysis experiment condition is with embodiment 1, and diluting compartment is 0.23M ZnSO ₄with 0.5M H ₂sO ₄mixed liquor, enriched chamber is 0.05M H ₂sO ₄, utmost point chamber is 0.1M Na ₂sO ₄.In experiment, current density is 35mA/cm ², the electrodialysis time is 60min.Electrodialysis experimental result shows, more " " change sulfonated poly (phenylene oxide) film, zinc ion slip does not reduce to 0.05% by 7.3% to acid-base pair, selects permeability to reduce to 0.003 by 0.49.

Embodiment 4

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.6g vinyl imidazole, stir 24h, and then add 0.02g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

Electrodialysis experiment condition is with embodiment 1, and diluting compartment is 0.23M ZnSO ₄with 0.5M H ₂sO ₄mixed liquor, enriched chamber is 0.05M H ₂sO ₄, utmost point chamber is 0.1M Na ₂sO ₄.In experiment, current density is 35mA/cm ², the electrodialysis time is 60min.Electrodialysis experimental result shows, more " acid-base pair " changes sulfonated poly (phenylene oxide) film, and zinc ion slip reduces to 0.05% by 7.3%, selects permeability to reduce to 0.003 by 0.49.

The dimethyl formamide that above-described embodiment adopts is pure for analyzing, Chemical Reagent Co., Ltd., Sinopharm Group; Vinyl imidazole is pure for analyzing, Aladdin reagent Shanghai Co., Ltd; Azodiisobutyronitrile is pure for analyzing, Tianjin recovery fine chemistry industry research institute.

In order to explain beneficial effect of the present invention from mechanism, a polyvalent cation selective diffusion barrier of preparing is carried out to infrared test, as shown in Figure 2 according to the inventive method.From infrared spectrum, can find out, all films that carry out " acid-base pair " change are at 3115cm ^-1all there is a new peak, corresponding to N ⁺the stretching vibration peak of-H, illustrates that imidazole ring is by sulfonic group proton.Meanwhile, 1055cm ^-1locating sulfonic stretching vibration peak moves to lower wave number section; 1220cm ^-1locate sulfonic asymmetric stretching vibration peak and move to high wave number section, this be because-SO-dipole causes with the interaction of protonated imidazole ring.This has just proved the formation of " acid-base pair " from characteristic peak two aspects of sulfonic characteristic peak and protonated imidazole ring.Why the prepared film of the inventive method has a good polyvalent cation separating effect, is mainly because after " acid-base pair " form, at the Internal architecture of film a proton transport passage, as shown in Figure 3.

Claims (3)

1. a preparation method with the cation-exchange membrane of a polyvalent cation Selective Separation function, it is characterized in that: take acidic polymer and alkaline monomer is raw material, make partly or completely " acid-base pair " change of acid ion cation exchange groups of acidic polymer, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

2. preparation method according to claim 1, is characterized in that: described acidic polymer is sulfonated poly (phenylene oxide); Described alkaline monomer is polyvinyl imidazol.

3. preparation method according to claim 2, is characterized in that: described preparation method carries out as follows:

0.5g sulfonated poly (phenylene oxide) is dissolved in 5ml dimethyl formamide, then adds 0.06-0.6g vinyl imidazole, stir 24h, and then add 0.002-0.02g azodiisobutyronitrile; At 80 ℃, react 10h and obtain uniform films liquid; Described uniform films liquid is coated on glass plate and dries 6h at 60 ℃, must there is the cation-exchange membrane of a polyvalent cation Selective Separation function.

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