CN102500338B - PFOA adsorbent and preparation method thereof - Google Patents

Abstract

The invention provides a PFOA adsorbent and a preparation method thereof. Wherein, the parent material of the PFOA adsorbent is rice husk fragments, wherein the surface of the adsorbent contains amino groups. The PFOA adsorbent can effectively remove PFOA.

Description

PFOA adsorbent and preparation method thereof

technical field

The invention belongs to the technical field of water treatment, in particular to an adsorption material for removing PFOA and a preparation method thereof.

Background technique

The reaction conditions of Atom Transfer Radical Polymerization (ATRP) are mild and controllable, the selectivity of monomers is wide, the molecular weight distribution of the synthesized polymer is narrow (Mw/Mn=1.1-1.5), the synthetic route is simple, and the molecular design strong ability. Surface-initiated atom transfer radical polymerization has been used for functional materials with polymer brushes on the surface, but less research has been done for the preparation of adsorbent materials.

Perfluorinated compounds (Perfluorinated Compounds, PFCs) are persistent, bioaccumulative and biotoxic, and are a new class of POPs. Perfluorooctanoic acid (PFOA) is one of the most widely used PFCs, and its pollution has also attracted widespread attention. The consumption of PFOA in my country is about 100 tons/year. PFOA has strong water solubility and is easy to remain in the water environment for a long time. The results of the researchers' investigation showed that there are different levels of PFOA pollution in surface water, groundwater and tap water in my country. Therefore, the research on PFOA removal technology is of great significance.

PFOA is stable in the environment, and it is difficult to remove it by traditional techniques such as biodegradation and redox. Ultrasonic radiation in an argon environment, zero-valent iron reduction in critical water, and ultraviolet radiation can degrade PFOA in aqueous solutions, but special environments are required and the cost is high. Adsorption is a commonly used sewage treatment technology. Studies have shown that adsorption can effectively remove PFOA in water. Among them, the removal of PFOA by activated carbon and resin is more researched. However, the existing adsorbents are not ideal in removing PFOA. Activated carbon has a low adsorption capacity, while the resin itself is expensive. Therefore, there is a need to develop new adsorbents for removing FPOA from water.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. The object of the present invention is to develop an adsorption material for removing PFOA by atom transfer radical polymerization (ATRP) technology.

Therefore, the present invention proposes a PFOA adsorbent whose parent material is rice husk fragments, wherein the surface of the adsorbent contains amino groups. The PFOA adsorbent can effectively remove PFOA.

According to an embodiment of the present invention, the above-mentioned PFOA adsorbent can also have the following additional technical features:

According to an embodiment of the present invention, the particle size of the adsorbent is 1-2 mm.

According to an embodiment of the present invention, the adsorption amount of PFOA is 1.8-2.4 mmol/g.

According to another aspect of the present invention, the present invention also proposes a method for preparing the above-mentioned PFOA adsorbent, which includes the following steps: connecting the GMA polymer on the surface of rice husk by ATRP reaction, so as to form RH-g-p (GMA); and An amino group is connected to the RH-g-p(GMA) through an ammoniation reaction, so as to obtain the PFOA adsorbent. Using this method, the above-mentioned PFOA adsorbent can be efficiently prepared, thereby enabling efficient removal of PFOA.

According to an embodiment of the present invention, the above method may also have the following additional technical features:

According to one embodiment of the present invention, the ATRP reaction to connect the GMA polymer on the surface of the rice husk further includes the following steps: mixing 40-50 mesh rice husk fragments with dichloromethane, bromoyl bromide, and pyridine, and heating the mixture at 25° C. Under reaction for 24 _hours to obtain ATRP reaction initiator RH-Br; , 4,7,10,10-hexamethyltri(ethylene)tetramine ligands were mixed, and the cuprous bromide and cupric bromide mixture were added to the mixture under the condition of blowing nitrogen, and the mixture was shaken at 45°C React in the bed for 2-3 hours to connect GMA polymer on the surface of rice husk to obtain RH-gp(GMA).

According to an embodiment of the present invention, the dosage ratio of the substances is as follows: 0.5g rice husk fragments: 15mL dichloromethane: 3mL bromoyl bromide: 1mL pyridine; 0.05g RH-Br: 2mL N,N-dimethylformyl : 3 mL GMA: 1 mL H ₂ O : 100 μL 1,1,4,7,10,10-hexamethyltri(ylidene)tetramine ligand: 45 mg cuprous bromide: 9 mg cupric bromide.

According to an embodiment of the present invention, the connecting amino groups on the RH-g-p(GMA) through an amination reaction to form the PFOA adsorbent further includes: mixing RH-g-p(GMA) with polyamines and tetrahydrofuran, React in a shaker at 25°C for 6-12h.

According to an embodiment of the present invention, the polyamine compound is ethylenediamine and diethylenetriamine, and the ratio of the substances is: 0.1g RH-g-p (GMA): 2mL polyamine: 2mL tetrahydrofuran.

According to an embodiment of the present invention, a method for removing PFOA in water is also proposed, which is characterized in that it includes: contacting water with the aforementioned PFOA adsorbent for a predetermined time. Those skilled in the art can determine the required amount of PFOA adsorbent and the required time according to the content of PFOA in the water, and details will not be repeated here.

The PFOA adsorbent of the present invention has the following advantages: rice husk is a cheap and abundant biological material, the present invention uses the ATRP method to modify the rice husk, and the amino group is evenly connected to the surface of the rice husk to obtain a particle size of 1- 2mm, the adsorption capacity of PFOA is 1.8-2.4mmol/g. Compared with activated carbon adsorbent, the adsorption capacity of PFOA is high; the polymer is connected to the surface of rice husk through chemical bonds, so the amino groups on the surface are not easy to fall off.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Detailed ways

The following describes the embodiments of the present invention in detail, and these embodiments are only used to explain the present invention, but should not be construed as limiting the present invention. If not clearly listed in the examples, the materials and methods used are conventional operations commonly used in the art.

general method

The method for preparing PFOA adsorbent:

1. Crush the rice husk to 40-50 mesh, wash thoroughly with deionized water, and dry at 25°C;

2. Insert ATRP initiation sites on the surface of rice husk fragments: add 15mL of dichloromethane, 3mL of bromoyl bromide, and 1mL of pyridine for every 0.5g of the above-mentioned rice husk fragments, and react at 25°C for 24h for the subsequent ATRP reaction Preparation of initiator RH-Br;

3. Link GMA polymer on the surface of rice husk by ATRP reaction to form RH-gp(GMA): add 2 mL N,N-dimethylformyl, 3 mL GMA, 1 mL H ₂ O, and 100 μL for every 0.05 g RH-Br 1, 1, 4, 7, 10, 10-hexamethyltri(sub)ethylenetetramine ligand, feed nitrogen to drive off the oxygen in the bottle, and add 45mg of cuprous bromide and 9mg of bromine under the condition of nitrogen Copper mixture, after ventilating for 10 minutes, seal the reaction vessel to prevent air from entering, place it in a shaker with a rotation speed of 150 rpm, keep the temperature constant at 45°C, react for 2-3 hours, wash with acetone and tetrahydrofuran, After drying, RH-gp(GMA) is obtained;

4. Connect amino groups on RH-g-p(GMA) through ammoniation reaction to form PFOA adsorbent: add 2mL ethylenediamine or 2mL diethylenetriamine and 2mL tetrahydrofuran mixed solution for every 0.1g RH-g-p(GMA), put In a shaker with a rotating speed of 150 rpm, the temperature is kept constant at 45° C. for 6-12 hours, washed with acetone and deionized water alternately, and dried to obtain the rice husk-based adsorption material.

The calculation method of adsorption capacity:

Add 0.01g of adsorbent to 100mL of aqueous solution containing 0.372mmol/LPFOA, adjust the pH of the solution to 5 with 0.1mol/L hydrochloric acid and 0.1mol/L sodium hydroxide, keep the temperature constant at 25°C, and the shaker speed at 150 rpm, the adsorption time is 24 hours, and the concentration of PFOA is measured by liquid chromatography.

The adsorption capacity is calculated according to the following formula:

q=(C ₀ -C _e )V/W

Among them: q-adsorption amount (mmol/g); C ₀ - PFOA concentration before adsorption (mmol/L); C _e - PFOA concentration after adsorption (mmol/L); V-solution volume (L); W-adsorbent Dry weight (g).

Example 1

In this example, the PFOA adsorbent was prepared according to the following steps:

(1) Take 0.5g of rice husk fragments, add 15mL of dichloromethane, 3mL of bromoyl bromide, and 1mL of pyridine, and react at 25°C for 24h to prepare the initiator RH-Br for the subsequent ATRP reaction;

(2) Put 0.05g RH-Br into a glass tube, add 2mL N,N-dimethylformyl, 3mL GMA, 1mL H ₂ O, and 100μL 1,1,4,7,10,10- Hexamethyltri(sub)ethylenetetramine ligand, feed nitrogen to drive away the oxygen in the bottle, and add 45mg of cuprous bromide and 9mg of copper bromide mixture under the condition of nitrogen, and after 10 minutes of ventilation, the glass The tube was sealed to prevent air from entering, placed in a shaker with a rotating speed of 150 rpm, and the temperature was kept constant at 45°C, reacted for 2 hours, washed with acetone and tetrahydrofuran, and dried to obtain RH-gp(GMA);

(3) Add 0.1g RH-g-p(GMA) into a glass tube containing 2mL ethylenediamine and 2mL tetrahydrofuran, place it in a shaker at a speed of 150 rpm, keep the temperature constant at 25°C, and react for 12h with Acetone and deionized water are washed alternately, and after drying, the rice husk-based adsorption material is obtained;

According to the calculation method of the adsorption capacity described above, the adsorption capacity of the prepared PFOA adsorbent was measured and calculated, and the result was that the adsorption capacity was 1.8mmol/g.

Example 2

In this example, the PFOA adsorbent was prepared according to the following steps:

(1) Take 0.5g of rice husk fragments, add 15mL of dichloromethane, 3mL of bromoyl bromide, and 1mL of pyridine, and react at 25°C for 24h to prepare the initiator RH-Br for the subsequent ATRP reaction;

(2) Put 0.05g RH-Br into a glass tube, add 2mL N,N-dimethylformyl, 3mL GMA, 1mL H ₂ O, and 100μL 1,1,4,7,10,10- Hexamethyltri(sub)ethylenetetramine ligand, feed nitrogen to drive away the oxygen in the bottle, and add 45mg of cuprous bromide and 9mg of copper bromide mixture under the condition of nitrogen, and after 10 minutes of ventilation, the glass The tube was sealed to prevent air from entering, placed in a shaker with a rotating speed of 150 rpm, and the temperature was kept constant at 45°C, reacted for 3 hours, washed with acetone and tetrahydrofuran, and dried to obtain RH-gp(GMA);

(3) Add 0.1g RH-g-p(GMA) into a glass tube containing 2mL ethylenediamine and 2mL tetrahydrofuran, place it in a shaker at a speed of 150 rpm, keep the temperature constant at 25°C, and react for 12h with Acetone and deionized water are washed alternately, and after drying, the rice husk-based adsorption material is obtained;

According to the calculation method of the adsorption capacity described above, the adsorption capacity of the prepared PFOA adsorbent was measured and calculated, and the result was that the adsorption capacity was 2.1mmol/g.

Example 3

In this example, the PFOA adsorbent was prepared according to the following steps:

(1) Take 0.5g of rice husk fragments, add 15mL of dichloromethane, 3mL of bromoyl bromide, and 1mL of pyridine, and react at 25°C for 24h to prepare the initiator RH-Br for the subsequent ATRP reaction;

(2) Put 0.05g RH-Br into a glass tube, add 2mL N,N-dimethylformyl, 3mL GMA, 1mL H ₂ O, and 100μL 1,1,4,7,10,10- Hexamethyltri(sub)ethylenetetramine ligand, feed nitrogen to drive away the oxygen in the bottle, and add 45mg of cuprous bromide and 9mg of copper bromide mixture under the condition of nitrogen, and after 10 minutes of ventilation, the glass The tube was sealed to prevent air from entering, placed in a shaker with a rotating speed of 150 rpm, and the temperature was kept constant at 45°C, reacted for 3 hours, washed with acetone and tetrahydrofuran, and dried to obtain RH-gp(GMA);

(3) Add 0.1g RH-g-p(GMA) into a glass tube containing 2mL ethylenediamine and 2mL tetrahydrofuran, place it in a shaker with a rotation speed of 150 rpm, keep the temperature at 25°C, and react for 6h with Acetone and deionized water are washed alternately, and after drying, the rice husk-based adsorption material is obtained;

According to the measuring and calculating method of the adsorption amount described above, the adsorption amount of the prepared PFOA adsorbent is measured and calculated, and the result is that the adsorption amount is 2.0mmol/g.

Example 4

In this example, the PFOA adsorbent was prepared according to the following steps:

(1) Take 0.5g of rice husk fragments, add 15mL of dichloromethane, 3mL of bromoyl bromide, and 1mL of pyridine, and react at 25°C for 24h to prepare the initiator RH-Br for the subsequent ATRP reaction;

(2) Put 0.05g RH-Br into a glass tube, add 2mL N,N-dimethylformyl, 3mL GMA, 1mL H ₂ O, and 100μL 1,1,4,7,10,10- Hexamethyltri(sub)ethylenetetramine ligand, feed nitrogen to drive away the oxygen in the bottle, and add 45mg of cuprous bromide and 9mg of copper bromide mixture under the condition of nitrogen, and after 10 minutes of ventilation, the glass The tube was sealed to prevent air from entering, placed in a shaker with a rotating speed of 150 rpm, and the temperature was kept constant at 45°C, reacted for 3 hours, washed with acetone and tetrahydrofuran, and dried to obtain RH-gp(GMA);

(3) Add 0.1g RH-g-p(GMA) into a glass tube containing 2mL diethylenetriamine and 2mL tetrahydrofuran, place it in a shaker with a rotation speed of 150 rpm, keep the temperature at 25°C, and react for 12h. Alternately washing with acetone and deionized water, and drying to obtain the rice husk-based adsorption material;

According to the calculation method of the adsorption capacity described above, the adsorption capacity of the prepared PFOA adsorbent is measured and calculated, and the result is that the adsorption capacity is 2.4mmol/g.

In the description of this specification, reference to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" means that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (4)

1. A method for preparing PFOA sorbent, is characterized in that, comprises the following steps: Attachment of GMA polymer on the surface of rice husk (RH) by ATRP reaction to form RH-g-pGMA; and connecting amino groups on the RH-g-pGMA through an ammoniation reaction, so as to obtain the PFOA adsorbent, Wherein, said connecting GMA polymer on the surface of rice husk by ATRP reaction further comprises the following steps: mixing 40-50 mesh rice husk fragments with dichloromethane, bromoyl bromide, and pyridine, and reacting at 25° C. for 24 hours to obtain the ATRP reaction initiator RH-Br; and In a reaction vessel, mix the ATRP reaction initiator RH-Br with N,N-dimethylformyl, GMA, H ₂ O and 1,1,4,7,10,10-hexamethyltriethylenetetra Amine ligands are mixed, and a mixture of cuprous bromide and copper bromide is added to the mixture under the condition of nitrogen gas, and the mixture is reacted in a shaking table at 45°C for 2-3 hours, so as to connect GMA polymer on the surface of rice husk to obtain RH -g-pGMA. 2. method according to claim 1, is characterized in that described substance consumption ratio is as follows: 0.5g rice husk fragments: 15mL dichloromethane: 3mL bromoyl bromide: 1mL pyridine; 0.05g RH-Br: 2mL N,N-Dimethylformyl: 3mL GMA: _1mL H2O: 100μL 1,1,4,7,10,10-Hexamethyltriethylenetetramine Ligand: 45mg bromide Cuprous: 9mg copper bromide. 3. method according to claim 1, is characterized in that, described by ammoniation on described RH-g-pGMA connects amino, forms described PFOA adsorbent and further comprises: Mix RH-g-pGMA with polyamine and tetrahydrofuran, and react in a shaker at 25°C for 6-12h. 4. The method according to claim 3, characterized in that: the polyamine is ethylenediamine and diethylenetriamine, and the ratio of the substance is: 0.1g RH-g-pGMA: 2mL polyamine: 2mL tetrahydrofuran .