Heavy metal ion adsorbent and preparation method thereof

A technology of heavy metal ions and adsorbents, applied in chemical instruments and methods, adsorption water/sewage treatment, other chemical processes, etc., can solve the problems of the ability to remove metal ions, affect the chelation of metal ions, etc., and achieve reuse rate High, easy to remove, good adsorption effect

Inactive Publication Date: 2015-04-22

BEIJING NORMAL UNIVERSITY +1

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The disadvantage of this method is that because the polymerized DNA is hydrophobic, the metal ions in the water cannot fully interact with the DNA molecules; moreover, the configuration of the po...

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Method used

[0029] The heavy metal ion adsorbent of the present invention is cored with silicon dioxide-coated ferric oxide, which has magnetic properties and is convenient for the separation of the adsorbent. In the present invention, there is no special limitation on the source of the silicon dioxide-coated ferric oxide, which can be prepared according to methods well known to those skilled in the art.

[0043] Spherical polyamide-amine dendrimers have a large specific surface area and can absorb more polyanions through static electricity to increa...

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Abstract

The invention provides a heavy metal ion adsorbent which contains nucleuses, polyamidoamine dendrimers grafted to the nucleuses through a silane compound and polyanions absorbed to the polyamidoamine dendrimers. The nucleuses are silicon dioxide coated ferroferric oxide. In the heavy metal ion adsorbent, the polyamidoamine dendrimers are absorbed with a layer of polyanions through electrostatic attraction, polyanions and especially the configuration of DNA is not changed, it is ensured that the outermost-layer polyanions can produce strong chelation with heavy metal ions during absorption, and accordingly the heavy metal ions in a water body are effectively removed. The heavy metal ion adsorbent is small in particle size and large in specific surface area. Furthermore, the polyamidoamine dendrimers with spherical structures can be further grafted to the polyamidoamine dendrimers and then the polyanions are absorbed to the polyamidoamine dendrimers, so that the heavy metal ion adsorbent is good in absorption effect and high in repeating utilization rate. In addition, the nucleuses in the heavy metal ion adsorbent are magnetic, so that separation is facilitated.

Application Domain

Other chemical processesWater contaminants +1

Technology Topic

IonHeavy metals +11

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Examples

Experimental program(7)
Comparison scheme(1)
Effect test(1)

Example Embodiment

[0045] The invention also discloses a preparation method of the heavy metal ion adsorbent, which comprises the following steps:

[0046] The nucleus of the polyamide-amine dendrimer grafted by the silane compound is ultrasonically dispersed in the buffer solution containing the polyanion, and then left to stand to obtain the heavy metal ion adsorbent;

[0047] The core is ferroferric oxide coated with silicon dioxide.

[0048] The ultrasonic dispersion time is preferably 5-20 minutes, and the standing time is preferably 5-30 minutes,

[0049] According to the present invention, preferably, before the core of the polyamide-amine dendrimer is grafted with ultrasonic dispersion, the method further includes: grafting the core and space structure of the polyamide-amine dendrimer with the silane compound to Spherical polyamide-amine dendrimers react in organic solvents to avoid light. Through the light-shielding reaction, the spherical polyamide-amine dendrimer is grafted onto the polyamide-amine dendrimer. The light-shielding reaction time is preferably 24 to 96 hours, more preferably 40-50 hours; the light-shielding reaction temperature is preferably room temperature, and the organic solvent is preferably methanol, ethanol or toluene. The mass ratio of the core of the grafted polyamide-amine dendrimer to the spherical polyamide-amine dendrimer with a spherical structure is 0.5-5:1. Preferably, the product of the light-shielding reaction reacts with a polyanion to obtain a heavy metal ion adsorbent. The mass ratio of the product of the light-shielding reaction to the heavy metal ion is preferably 1:1-20:1.

[0050] According to the present invention, the preparation method of the core grafted with polyamide-amine dendrimer is preferably carried out according to the following steps:

[0051] After the core and the silane compound are uniformly mixed in the organic solvent, the reaction is performed to obtain the 0-generation polyamide-amine grafted core;

[0052] The silane compound is 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β( Aminoethyl)-γ-aminopropyl methyldimethoxysilane, N-β(aminoethyl)-γ-aminopropyl triethoxysilane, N-β(aminoethyl)-γ-ammonia Propylmethyldiethoxysilane or aminoethylaminopropyltrimethoxysilane.

[0053] The 0-generation polyamide-amine dendrimer grafted core reacts with methyl acrylate to obtain the 0.5-generation polyamide-amine dendrimer grafted core;

[0054] The 0.5-generation polyamide-amine dendrimer grafted core and ethylenediamine undergo an ester group amidation reaction to obtain the first-generation polyamide-amine dendrimer grafted core;

[0055] The first generation polyamide-amine dendrimer grafted core reacts with methyl acrylate to obtain the 1.5 generation polyamide-amine dendrimer grafted core.

[0056] The preparation method of the whole generation or half generation polyamide-amine dendrimer grafted core can be prepared according to the above method. The polyamide-amine dendrimer grafted onto the core by a silane compound may be a full-generation polyamide-amine dendrimer or a half-generation polyamide-amine dendrimer. The generation number of the polyamide-amine dendrimer is preferably 1 to 10 generations, more preferably 1.5 to 5 generations.

[0057] Due to the influence of the space structure of the core, the polyamide-amine dendrimer is dendritic, and preferably a polyamide-amine tree with spherical space structure is grafted onto the polyamide-amine dendrimer Like macromolecules. The polyamide-amine dendrimers with spherical steric structure are preferably polyamide-amine dendrimers with spherical steric structure of the whole generation, and the surface of which is amino groups.

[0058] The preparation method of the polyamide-amine dendrimer with spherical structure of the whole generation is as follows:

[0059] The half-generation spherical polyamide-amine dendrimer is slowly added dropwise to the methanol solution of ethylenediamine, and the reaction is carried out at room temperature for 64 hours to obtain the entire generation spherical polyamide-amine dendrimer with the amine group as the periphery. The product was washed and purified with methanol, and the excess ethylenediamine was removed with a rotary evaporator to obtain a whole generation of spherical polyamide-amine dendrimers.

[0060] The preparation method of the semi-generation spherical polyamide-amine dendrimer is:

[0061] Methyl acrylate is dissolved in methanol, and the entire generation of dendrimer (ethylenediamine is regarded as generation 0) methanol solution is slowly added dropwise, and reacted at room temperature for 24 hours. Michael addition reaction occurs to obtain ethylenediamine as the core Half-generation dendrimers. The excess methyl acrylate and solvent are removed by rotary evaporation to obtain a viscous semi-spherical polyamide-amine dendrimer.

[0062] The polyamide-amine dendrimer whose steric structure is spherical is preferably from 1 to 10 generations, and more preferably from 2 to 5 generations.

[0063] The spherical polyamide-amine dendrimer has a large specific surface area, which can adsorb more polyanions through static electricity, increasing the adsorption effect of the heavy metal ion adsorbent. Moreover, the heavy metal ion adsorbent in which the polyamide-amine dendrimer is grafted with the spherical polyamide-amine dendrimer can be reused.

Example Embodiment

[0065] Example 1

[0066] At 25℃, 5.4g FeSO 4 ·7H 2 O and 6.8g FeCl 3 (Mole ratio: Fe(III)/Fe(II)=2:1) was dissolved in 130 mL of high-purity argon deoxygenated water, stirred and added dropwise concentrated ammonia (about 60 mL) until the pH was 10.0. Then, it was heated at 65°C for 50 minutes, and the magnetic nanomaterial was collected by contacting the outer wall of the container with a magnet to obtain the black powder, and the magnetic nanomaterial was washed with deionized water 3 times to neutrality. Under the protection of nitrogen, 2g of the synthesized magnetic Fe 3 O 4 The nanomaterials were dispersed in absolute ethanol, 60mL ammonia and 4mL tetraethylorthosilicate (TEOS, Si(OC 2 H 5 ) 4 ). After sonicating in an ice-water bath for 2 hours, the product was collected by touching the wall of the container with a magnet, washed 3 times with absolute ethanol, and dried under vacuum (70℃, about 12h) to obtain silica-coated magnetic nanoparticles (Fe 3 O 4 SiO 2 ).

Example Embodiment

[0067] Example 2

[0068] Add 0.5g Fe 3 O 4 SiO 2 The particles, 30 mL of toluene and 5 mL of 3-aminopropyltriethoxysilane were added to a 50 mL flask, and the mixture was sonicated for 30 minutes and reacted at 110° C. for 8 hours. After the reaction, the product and the liquid were separated with a magnet, and washed with absolute ethanol 5 times (5 mL each time), and the resulting product was vacuum dried at 50° C. for 24 h. The product is 0 generation polyamide-amine graft (Fe 3 O 4 SiO 2 PADD G0).

[0069] 0.3g Fe 3 O 4 SiO 2 PADD G0 and 10mL methanol were added to the round-bottomed flask, sonicated for 30min to make Fe 3 O 4 SiO 2 PADD G0 was dispersed, and then 0.1 mL of methyl acrylate was slowly added to the flask, and reacted at 50°C for 48 hours. After the reaction, the product is separated from the liquid with a magnet, and washed with anhydrous methanol 5 times (2mL each time), the resulting product is vacuum dried at 50°C for 24h, and the product is Fe 3 O 4 SiO 2 PADD G0.5.

[0070] 0.3g Fe 3 O 4 SiO 2 PADD G0.5 and 10mL methanol were added to the round bottom flask, and the nanomaterials were dispersed by ultrasonic for 30min, and then 0.2mL ethylenediamine was slowly added to the flask, and the mixture was reacted at 50℃ for 48h and purified to obtain 1 generation Polyamide-amine graft (Fe 3 O 4 SiO 2 PADD G1.0).

[0071] 0.3g Fe 3 O 4 SiO 2 PADD G1.0 and 10mL methanol were added to the round bottom flask, ultrasonic for 30min to disperse the nanomaterials, then 0.1mL methyl acrylate was slowly added to the flask, reacted at 50℃ for 48h and purified to obtain 1.5 generation polyamide- Amine graft (Fe 3 O 4 SiO 2 PADD G1.5).

[0072] Thermogravimetric analysis (TGA) was used to characterize the synthesized grafts. TGA was performed on the TGA/DSC1 thermogravimetric analyzer (Mettler-Toledo, Switzerland). 1-3 mg of sample was added to the alumina sample pan, and the temperature was increased from 25°C at a temperature of 20°C/min under the protection of nitrogen. ℃ heated to 600 ℃. Fe 3 O 4 SiO 2 The grafting rates of branched PADD on PADD G0.5, G1.0 and G1.5 were 8.4%, 9.3% and 12.1%, respectively.

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Classification and recommendation of technical efficacy words

Easy to remove
Small particle size

Heavy metal ion adsorbent and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

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