Indium oxychloride micron sheet adsorbent as well as preparation method and application thereof

Abstract

The invention provides an indium oxychloride micron-sheet adsorbent, a preparation method thereof and application of the indium oxychloride micron-sheet adsorbent in adsorbing and removing perfluorooctanoic acid in water. According to the method, firstly, indium chloride hydrate is dissolved in a diluted hydrochloric acid solution, then indium oxychloride is obtained through a one-step calcination method, the synthesis steps are simple and rapid, and large-batch rapid preparation of the indium oxychloride micron sheet adsorbent can be achieved. The indium oxychloride micron sheet adsorbent prepared by the invention can expose abundant adsorption sites, can realize efficient removal of perfluorooctanoic acid pollutants by means of static electricity, ion exchange and the like, and the adsorption capacity can reach 748mg / g, which is 11 times of that of commercial granular active carbon. The indium oxychloride micron sheet adsorbent prepared by the invention has a unique two-dimensional micron sheet structure and surface electropositivity, can effectively remove perfluorooctanoic acid pollutants in water, and is expected to realize adsorption removal of other common anion pollutants (such as dyes and inorganic oxyacid radicals).

Description

Technical Field

[0001] The invention belongs to the technical field of water pollution control, and in particular relates to an indium oxychloride micron sheet adsorbent and a preparation method and application thereof. Background Art

[0002] In recent years, new pollutants represented by perfluorinated compounds have received widespread attention worldwide. Perfluorooctanoic acid (PFOA) is the most representative perfluorinated compound, which has environmental persistence, bioaccumulation and potential biological toxicity. The PFOA molecular structure has a hydrophobic perfluoroalkyl chain at one end and a hydrophilic carboxylate at the other end. Its unique amphiphilic structure makes it have good hydrophilicity and lipophilicity. It is widely used in aqueous film-forming foam fire extinguishers, textiles and electroplating. It enters the environment during production and consumption and has become the most widely distributed and most detected perfluorinated compound in my country. At the same time, due to the high-energy C-F covalent bond in its molecules, it has excellent chemical and thermal stability. It is difficult to undergo natural photolysis, hydrolysis and biodegradation when released into the environment, and the harm to the ecological environment and human health is becoming increasingly prominent. In addition, studies have shown that even if it is exposed to low levels of PFOA, long-term exposure may still cause damage to the immune system, thyroid and liver, and even cause cancer. Therefore, the development of efficient PFOA control technology has become a hot spot and difficulty in the current field of new pollutant control.

[0003] At present, the main economically feasible PFOA removal technologies include activated carbon adsorption, ion exchange and reverse osmosis technology. Among them, activated carbon adsorption technology has the advantages of low cost and simple operation, and has become a technology widely concerned by the scientific research and industry. However, the current activated carbon adsorption technology still has problems such as slow adsorption kinetics and limited adsorption capacity, and it is urgent to develop efficient adsorbents to achieve efficient removal of PFOA in water. Summary of the invention

[0004] The first object of the present invention is to provide an indium oxychloride micron sheet adsorbent and a preparation method thereof; the second object is to provide the use of the adsorbent in adsorbing and removing PFOA pollutants in water.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing an indium oxychloride micron sheet adsorbent, which comprises the following steps: (1) dissolving a metal indium salt precursor in a dilute hydrochloric acid solution to obtain a precursor solution; (2) placing the precursor solution in a container for calcination to obtain a powder; and (3) washing and vacuum drying the powder in sequence to obtain the indium oxychloride micron sheet adsorbent.

[0007] Furthermore, in step (1), the metal indium salt is InCl3·4H2O or In(NO3)3·4H2O.

[0008] Furthermore, in step (1), the metal indium salt is specifically InCl3·4H2O.

[0009] Furthermore, in step (1), the concentration of the dilute hydrochloric acid solution is 0.1-0.3 mmol / L.

[0010] Furthermore, in step (2), the calcination treatment temperature is 250-350°C, the heating rate is 10-30°C / min, and the time is 1-4h.

[0011] Furthermore, in step (3), the washing treatment is washing with water until the pH of the supernatant is 6-8, and then washing with ethanol 2-3 times; the temperature of the vacuum drying treatment is 50-70°C and the time is 8-16h.

[0012] Furthermore, in step (3), the washing treatment is specifically washing with ultrapure water until the pH of the supernatant is near neutral, and then adsorbing with ethanol twice, and the vacuum drying treatment is specifically vacuum drying at 60°C for 12 hours.

[0013] The present invention also provides an indium oxychloride micron sheet adsorbent prepared by the above-mentioned preparation method of the indium oxychloride micron sheet adsorbent.

[0014] Furthermore, the indium oxychloride micron sheet adsorbent is a two-dimensional sheet structure; wherein the length and width of the two-dimensional sheet structure are 2-20 μm, and the thickness is 100-200 nm.

[0015] The present invention also provides the use of the indium oxychloride microsheet adsorbent as described above in the adsorption and removal of perfluorooctanoic acid pollutants in water.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention adopts a one-step calcination method, and the structure regulation of the indium oxychloride micron sheet adsorbent can be achieved by simply controlling the calcination temperature and calcination time. It has the advantages of simple synthesis process and good repeatability, and is suitable for rapid large-scale industrial production.

[0018] (2) The adsorbent provided by the present invention is an indium oxychloride micron sheet adsorbent, which can adsorb and remove perfluorooctanoic acid in water. The adsorbent has abundant adsorption sites and can remove PFOA in water through adsorption mechanisms such as electrostatics and ion exchange, thereby solving the problems of slow adsorption rate and limited adsorption capacity in the process of conventional activated carbon removing PFOA, and can achieve rapid and efficient removal of PFOA pollutants in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 is a scanning electron microscope image of the indium oxychloride adsorbent in Example 1 and Example 2;

[0021] Figure 2 is the XRD spectrum of the indium oxychloride microsheet adsorbent in Example 1;

[0022] Figure 3 The adsorption kinetics of PFOA by the indium oxychloride microsheet adsorbent and the granular activated carbon (GAC) adsorbent in Example 1; wherein the adsorbent concentration is 0.25 g / L and the PFOA concentration is 20 mg / L;

[0023] Figure 4 is the adsorption isotherm of the indium oxychloride microsheet adsorbent in Example 1;

[0024] Figure 5 is the zeta potential diagram of the indium oxychloride microsheet adsorbent in Example 1;

[0025] Figure 6 The Cl - Release diagram. DETAILED DESCRIPTION

[0026] The inventors found that indium oxychloride is a typical layered metal oxychloride, with In-O layers and Cl atoms connected by weak van der Waals forces, and has good electron mobility, abundant surface atoms and adjustable electronic structure. PFOA exists in aqueous solution as perfluorooctanoic acid anions, so it is easy to electrostatically adsorb with In-O cationic layers. At the same time, the abundant In atoms exposed on the surface can also complex with the terminal carboxyl groups of PFOA, further improving the affinity for PFOA. Therefore, indium oxychloride is expected to become a very promising adsorbent for effectively removing PFOA from water.

[0027] The present invention is described in detail below in conjunction with specific implementation modes.

[0028] In view of the problem that conventional adsorbents currently have slow adsorption of PFOA and limited adsorption capacity, the present invention provides a method for preparing an indium oxychloride micron sheet adsorbent, comprising the following steps:

[0029] S1, dissolving a metal indium salt precursor in a dilute hydrochloric acid solution to obtain a precursor solution;

[0030] S2, dropping the precursor solution into a glass culture dish, and placing it in a muffle furnace for calcination;

[0031] S3. The calcined powder is washed and vacuum dried to obtain indium oxychloride micron sheets.

[0032] In a preferred embodiment of the present invention, in step S1, the metal indium salt is InCl3·4H2O;

[0033] In a preferred embodiment of the present invention, in step S1, the concentration of the dilute hydrochloric acid is 0.2 mol / L;

[0034] In a preferred embodiment of the present invention, in step S2, during the calcination process, the calcination temperature in the muffle furnace is 280° C., the heating rate is 20° C. / min, and the calcination time is 2 h.

[0035] In a preferred embodiment of the present invention, in step S3, a large amount of ultrapure water is used in the washing process until the pH of the supernatant is nearly neutral, and then the supernatant is adsorbed with ethanol twice, and then vacuum dried at 60° C. for 12 hours.

[0036] The present invention also provides application of the indium oxychloride micron sheet in adsorbing and removing typical perfluorinated compounds in water.

[0037] In a preferred embodiment of the present invention, the typical perfluorinated compound pollutant is PFOA.

[0038] The following is a detailed description of an indium oxychloride micron sheet adsorbent, a preparation method and an application thereof of the present invention through specific examples.

[0039] Example 1

[0040] This embodiment provides an indium oxychloride micron sheet adsorbent, and the preparation method thereof is as follows:

[0041] Weigh 1.47g InCl3·4H2O and dissolve it in 10mL 0.2mol / L dilute hydrochloric acid solution, mix and stir for 30min until it is completely dissolved; use a pipette to transfer 5mL and drop it into a glass petri dish with a diameter of 10cm, transfer it into a muffle furnace for calcination, set the calcination temperature to 280 degrees, the calcination time to 2h, and the heating rate to 20℃ / min. The calcined powder was washed with a large amount of ultrapure water until the pH of the supernatant was nearly neutral, then washed twice with ethanol, and transferred to a 60℃ oven for vacuum drying for 12h to obtain an indium oxychloride micron sheet adsorbent.

[0042] Example 2

[0043] This embodiment provides an indium oxychloride micron sheet adsorbent, and the preparation method thereof is as follows:

[0044] Weigh 1.47g InCl3·4H2O and dissolve it in 10mL 0.2mol / L dilute hydrochloric acid solution, mix and stir for 30min until it is completely dissolved; use a pipette to transfer 5mL and drop it into a glass petri dish with a diameter of 10cm, transfer it into a muffle furnace for calcination, set the calcination temperature to 280 degrees, the calcination time to 3h, and the heating rate to 20℃ / min. The calcined powder was washed with a large amount of ultrapure water until the pH of the supernatant was nearly neutral, then washed twice with ethanol, and transferred to a 60℃ oven for vacuum drying for 12h to obtain an indium oxychloride micron sheet adsorbent.

[0045] Example 3

[0046] This embodiment provides an indium oxychloride micron sheet adsorbent, and the preparation method thereof is as follows:

[0047] Weigh 1.47g InCl3·4H2O and dissolve it in 10mL 0.2mol / L dilute hydrochloric acid solution, mix and stir for 30min until it is completely dissolved; use a pipette to transfer 5mL and drop it into a glass petri dish with a diameter of 10cm, transfer it into a muffle furnace for calcination, set the calcination temperature to 320 degrees, the calcination time to 2h, and the heating rate to 20℃ / min. The calcined powder was washed with a large amount of ultrapure water until the pH of the supernatant was nearly neutral, then washed twice with ethanol, and transferred to a 60℃ oven for vacuum drying for 12h to obtain an indium oxychloride micron sheet adsorbent.

[0048] exist Figure 1 Figures a and b are scanning electron micrographs of the InOCl adsorbent obtained by calcining at 280 degrees for 2 hours and 3 hours, respectively. Figure 1 It can be seen that precise control of the calcination time can achieve the regulation of the morphology and structure of InOCl adsorbent.

[0049] Figure 2 It is the XRD spectrum of the prepared InOCl micron flake adsorbent, indicating that the synthesized adsorbent is pure phase InOCl and does not contain other crystalline impurities.

[0050] Figure 3 This is a test of the adsorption kinetics of 20 mg / L PFOA by InOCl micron sheet adsorbent and GAC. Compared with GAC, InOCl has faster adsorption kinetics and its adsorption removal performance is much higher than that of conventional GAC adsorbent.

[0051] Figure 4 This is the adsorption isotherm of InOCl microsheet adsorbent for PFOA of different concentrations. After fitting with the Langmuir and Freundlich models respectively, it was found that the adsorption of PFOA was more consistent with the Freundlich curve. The maximum adsorption amount obtained by fitting with the Langmuir model was 748 mg / g, which is 11 times that of the traditional GAC adsorbent.

[0052] Figure 5 and Figure 6 They are the zeta potential test of InOCl and the Cl - From the release of InOCl, it can be concluded that the adsorption of PFOA by InOCl is achieved through electrostatic attraction and ion exchange, so it has more excellent adsorption performance.

[0053] In summary, the indium oxychloride microsheet adsorbent prepared by the present invention can expose abundant adsorption sites, and can achieve efficient removal of perfluorooctanoic acid pollutants by means of electrostatics and ion exchange, and the adsorption capacity can reach 748 mg / g, which is 11 times that of commercial granular activated carbon. The indium oxychloride microsheet adsorbent prepared by the present invention has a unique two-dimensional microsheet structure and surface positive charge, which can not only effectively remove perfluorooctanoic acid pollutants in water, but also is expected to achieve adsorption and removal of other common anionic pollutants (such as dyes and inorganic oxygen-containing acid radicals).

[0054] Those skilled in the art will appreciate that the above embodiments are specific examples of the present invention, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present invention. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present invention, and therefore the scope of protection of the present invention shall be subject to the scope defined in the claims.

Claims

1. A method for preparing an indium oxychloride micron sheet adsorbent, characterized in that: The preparation method comprises the following steps: (1) dissolving a metal indium salt precursor in a dilute hydrochloric acid solution to obtain a precursor solution; (2) placing the precursor solution in a container and calcining it to obtain a powder; (3) The powder is sequentially washed and vacuum dried to obtain the indium oxychloride micron sheet adsorbent.

2. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 1, characterized in that: In step (1), the metal indium salt is InCl3·4H2O or In(NO3)3·4H2O.

3. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 2, characterized in that: In step (1), the metal indium salt is specifically InCl3·4H2O.

4. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 1, characterized in that: In step (1), the concentration of the dilute hydrochloric acid solution is 0.1-0.3 mmol / L.

5. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 1, characterized in that: In step (2), the calcination treatment temperature is 250-350°C, the heating rate is 10-30°C / min, and the time is 1-4h.

6. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 1, characterized in that: In step (3), the washing treatment is to wash with water until the pH value of the supernatant is 6-8, and then wash with ethanol 2-3 times; the temperature of the vacuum drying treatment is 50-70°C and the time is 8-16h.

7. The method for preparing the indium oxychloride micron sheet adsorbent according to claim 6, characterized in that: In step (3), the washing treatment is specifically washing with ultrapure water until the pH of the supernatant is nearly neutral, and then adsorbing with ethanol twice. The vacuum drying treatment is specifically vacuum drying at 60°C for 12 hours. 8 . The indium oxychloride micro-sheet adsorbent prepared by the method for preparing the indium oxychloride micro-sheet adsorbent according to claim 1 .

9. The indium oxychloride microsheet adsorbent according to claim 8, characterized in that: The indium oxychloride micron sheet adsorbent is a two-dimensional sheet structure; wherein the length and width of the two-dimensional sheet structure are 2-20 μm, and the thickness is 100-200 nm.

10. Use of the indium oxychloride microsheet adsorbent as claimed in claim 8 in the adsorption and removal of perfluorooctanoic acid pollutants in water.

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