Iron nano colloid adsorbent, preparation method thereof and application of iron nano colloid adsorbent in treatment of acidic phosphorus polluted underground water

Abstract

The invention provides an iron nano colloid adsorbent, a preparation method thereof and application of the iron nano colloid adsorbent in treatment of acidic phosphorus polluted underground water, and belongs to the technical field of environmental protection. The iron nano colloid adsorbent comprises the following raw materials in parts by weight: 1 part of Fe3O4 nano particles and 10-20 parts of polyethyleneimine, and the iron nano particles have large specific surface area and high reaction activity and can quickly adsorb phosphate in water in a short time. Amino groups contained in PEI molecules interact with phosphate ions in water to form a stable complex, the dispersity of the nanoparticles can be improved, the particles are prevented from being gathered in the water, and therefore the treatment effect is improved. The iron nano colloid adsorbent disclosed by the invention can efficiently fix phosphate, can keep a good treatment effect under the condition of high-concentration phosphorus, and is suitable for the quick response requirement in actual treatment of acidic phosphorus polluted underground water, and an indissolvable iron phosphorus compound of a treated product can stably exist and cannot cause secondary pollution to the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and in particular relates to an iron nano-colloid adsorbent and a preparation method thereof, and application thereof in the treatment of acidic phosphorus-contaminated groundwater. Background Art

[0002] Phosphogypsum is the main by-product of phosphoric acid production. Its chemical composition is mainly calcium sulfate dihydrate (CaSO 4 ·2H 2 O), and also contains a certain amount of impurities such as phosphorus, fluorine, and heavy metals. Due to the huge output of phosphogypsum, hundreds of millions of tons of phosphogypsum are produced worldwide each year. How to treat and utilize these phosphogypsum has become a global problem. In addition, the leachate from the phosphogypsum storage site is usually acidic and contains a high concentration of phosphate. Phosphate is an important nutrient element, but its excessive presence in the environment can lead to a series of problems, such as eutrophication of water bodies. Eutrophication can cause algae to multiply in large numbers, leading to hypoxia in water bodies, destroying aquatic ecosystems, and even causing large-scale fish deaths in severe cases. In addition, harmful substances such as heavy metals and fluorides in phosphogypsum will also enter groundwater with leachate, further exacerbating environmental pollution. Therefore, how to effectively treat the high concentration of phosphorus in phosphogypsum-contaminated (acidic) groundwater has become a problem that needs to be solved urgently.

[0003] In the prior art, methods for treating groundwater contaminated by phosphogypsum mainly include chemical precipitation, biological treatment, membrane separation and electrochemical methods. However, the existing treatment methods have many limitations such as high treatment cost, low treatment efficiency and complex equipment maintenance when facing groundwater with high phosphorus concentration and acidic conditions. Therefore, there is an urgent need for a new, efficient, adaptable and environmentally friendly treatment technology to solve the problem of high phosphorus concentration in groundwater contaminated by phosphogypsum. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes an iron nano-colloid adsorbent and a preparation method thereof and application thereof in the treatment of acidic phosphorus-contaminated groundwater.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] An iron nano-colloid adsorbent, the raw materials include Fe 3 O 4 1 part of nanoparticles and 10-20 parts of polyethyleneimine (PEI).

[0008] The principle of the iron nano-colloid adsorbent of the present invention to remove phosphorus from acidic phosphorus-contaminated groundwater:

[0009] The iron nanoparticles in the iron nanocolloid adsorbent have a large specific surface area and high reactivity, and can quickly adsorb phosphate in water in a short time. The amino group (-NH 2 ) interacts with phosphate ions in water to form a stable complex. In addition, PEI can also improve the dispersibility of iron nanoparticles and prevent particles from aggregating in water, thereby improving the treatment effect. Iron nanocolloid adsorbents also provide multiple mechanisms such as physical adsorption through electrostatic adsorption and high specific surface area and pore structure to further enhance the adsorption capacity of phosphate ions. Under the above-mentioned effects, nanocolloids can significantly reduce the phosphorus concentration in acidic phosphorus-contaminated groundwater in a short period of time, and the reaction is not only fast, but also has a good adsorption effect.

[0010] Furthermore, the Fe 3 O 4 The nanoparticle raw material comprises the following components in parts by weight: 1-2 parts of FeOOH fine powder, 20-30 parts of oleic acid and 40-50 parts of 1-octadecene.

[0011] Furthermore, the Fe 3 O 4 The method for preparing nanoparticles comprises the following steps:

[0012] FeOOH fine powder, oleic acid and 1-octadecene were weighed in parts by weight, mixed and stirred, and then heated in an argon environment for pyrolysis reaction. After the reaction was completed, purification was performed to obtain the Fe 3 O 4 Nanoparticles.

[0013] Furthermore, the FeOOH fine powder is used as an iron precursor, oleic acid is used as a stabilizer, and 1-octadecene is used as a solvent.

[0014] Furthermore, the mixing and stirring is carried out at a temperature of 80-150° C., preferably 120° C., for 1 hour to remove the residual moisture of oleic acid and 1-octadecene.

[0015] Furthermore, the temperature of the pyrolysis reaction is 300-400°C and the time is 1-1.5h, preferably the temperature is 320°C and the time is 1h.

[0016] Furthermore, the particle size of the FeOOH fine powder after screening is less than 0.6 mm.

[0017] Furthermore, the purification step is carried out by acetone and methanol for 5-6 times to remove excess iron salts and organic molecules.

[0018] Further, by weight, the raw materials include Fe 3 O 4 1 part of nanoparticles and 10 parts of polyethyleneimine.

[0019] The second technical solution of the present invention:

[0020] A method for preparing the iron nanocolloid adsorbent comprises the following steps: weighing Fe 3 O 4 Nanoparticles and polyethyleneimine are mixed to obtain the iron nanocolloid adsorbent.

[0021] The third technical solution of the present invention:

[0022] The application of the iron nano-colloid adsorbent in the treatment of acidic phosphorus-contaminated groundwater.

[0023] The fourth technical solution of the present invention:

[0024] A method for removing phosphorus from acidic phosphorus-contaminated groundwater, comprising adding the iron nano-colloid adsorbent to the acidic phosphorus-contaminated groundwater, mixing and stirring, and removing phosphorus from the acidic phosphorus-contaminated groundwater;

[0025] Alternatively, the iron nano-colloid adsorbent is used as a filter element of a water purification device, and the acidic phosphorus-contaminated groundwater is made to flow through the water purification device to achieve the removal of phosphorus in the acidic phosphorus-contaminated groundwater.

[0026] Furthermore, the dosage of the iron nano-colloid adsorbent in acidic phosphorus-contaminated groundwater is 1-2 g / 10-20 L.

[0027] Furthermore, the pH of the acidic phosphorus-contaminated groundwater is 3-4, preferably pH 3.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] 1. The iron nano-colloid adsorbent of the present invention can efficiently fix phosphate and can still maintain a good treatment effect under conditions of high phosphorus concentration.

[0030] 2. The iron nano-colloid adsorbent of the present invention can adapt to acidic environments and can maintain excellent treatment effects when treating groundwater contaminated by phosphogypsum.

[0031] 3. The iron nanocolloid adsorbent of the present invention can react quickly in the treatment of acidic phosphorus-contaminated groundwater. The adsorption process is rapid and the phosphorus concentration in the acidic phosphorus-contaminated groundwater can be significantly reduced within 10 minutes. It is suitable for the rapid response requirements in the actual treatment of acidic phosphorus-contaminated groundwater.

[0032] 4. The present invention is environmentally friendly. The prepared iron nano-colloidal adsorbent will not introduce new pollutants during the treatment process. The product after treatment is an insoluble iron-phosphorus compound that can exist stably and will not cause secondary pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 Schematic diagram of the structure of the water purification device, wherein 1 is a shell, 2 is a water inlet pipe, 3 is a top cover, 4 is a sand and gravel layer, 5 is an activated carbon layer, 6 is a filter element filled with liquid iron nano-colloid adsorbent, 7 is a biofilm layer, 8 is a water outlet pipe, 9 is a hollow cylinder, 10 is a filter membrane element, 11 is a through hole, and 12 is a water inlet;

[0035] Figure 2 This is a transmission electron microscope characterization image of the iron nanocolloid adsorbent prepared in Example 1;

[0036] Figure 3 The adsorption kinetics diagram of the iron nano-colloid adsorbent prepared in Example 1 in Application Example 1 for treating simulated phosphorus-contaminated water;

[0037] Figure 4 This is a diagram showing the effect of treating acidic phosphorus-contaminated groundwater with the iron nano-colloid adsorbent prepared in Example 1 in Application Example 2;

[0038] Figure 5 This is a rendering showing the reusability of the iron nano-colloidal adsorbent prepared in Example 1 in Application Example 2 for treating acidic phosphorus-contaminated groundwater. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] The embodiment of the present invention provides an iron nanocolloid adsorbent, which comprises, by weight, Fe 3 O 4 1 part of nanoparticles and 10-20 parts of polyethyleneimine (PEI).

[0045] In a preferred embodiment of the present invention, the raw material includes Fe 3 O 4 1 part of nanoparticles and 10 parts of polyethyleneimine.

[0046] In a preferred embodiment of the present invention, the Fe 3 O 4 The nanoparticle raw material comprises the following components in parts by weight: 1-2 parts of FeOOH fine powder, 20-30 parts of oleic acid and 40-50 parts of 1-octadecene.

[0047] In a preferred embodiment of the present invention, the Fe 3 O 4 The method for preparing nanoparticles comprises the following steps:

[0048] FeOOH fine powder, oleic acid and 1-octadecene were weighed in parts by weight, mixed and stirred, and then heated in an argon environment for pyrolysis reaction. After the reaction was completed, purification was performed to obtain the Fe 3 O 4 Nanoparticles.

[0049] More specifically, the FeOOH fine powder is used as an iron precursor, oleic acid is used as a stabilizer, and 1-octadecene is used as a solvent.

[0050] More specifically, the mixing and stirring is carried out at a temperature of 80-150° C., preferably at 120° C., for 1 hour to remove the residual moisture of oleic acid and 1-octadecene.

[0051] More specifically, the temperature of the pyrolysis reaction is 300-400°C, and the time is 1-1.5 hours, preferably the temperature is 320°C, and the time is 1 hour.

[0052] More specifically, the FeOOH fine powder has a particle size of less than 0.6 mm after screening.

[0053] More specifically, the purification step is performed by acetone and methanol for 5-6 times to remove excess iron salts and organic molecules.

[0054] The present invention also provides a method for preparing the iron nanocolloid adsorbent, comprising the following steps: weighing Fe 3 O 4 Nanoparticles and polyethyleneimine are mixed to obtain the iron nanocolloid adsorbent.

[0055] The embodiment of the present invention also proposes the use of the iron nano-colloid adsorbent in the treatment of acidic phosphorus-contaminated groundwater.

[0056] The embodiment of the present invention also provides a method for removing phosphorus from acidic phosphorus-contaminated groundwater, wherein the iron nano-colloid adsorbent is added to the acidic phosphorus-contaminated groundwater, mixed and stirred, to achieve the removal of phosphorus from the acidic phosphorus-contaminated groundwater;

[0057] Alternatively, the iron nano-colloid adsorbent is used as a filter element of a water purification device, and the acidic phosphorus-contaminated groundwater is made to flow through the water purification device to achieve the removal of phosphorus in the acidic phosphorus-contaminated groundwater.

[0058] In the preferred embodiment of the present invention, the structural schematic diagram of the water purification device used is shown in Figure 1 , wherein 1 is a shell, 2 is a water inlet pipe, 3 is a top cover, 4 is a sand and gravel layer, 5 is an activated carbon layer, 6 is a filter element filled with liquid iron nano-colloidal adsorbent, 7 is a biofilm layer, 8 is a water outlet pipe, 9 is a hollow cylinder, 10 is a filter membrane element, 11 is a through hole, and 12 is a water inlet. The filter element 6 filled with liquid iron nano-colloidal adsorbent includes a hollow cylinder 9 and filter membrane elements 10 sequentially arranged around the outer circumference of the hollow cylinder 9. The hollow cylinder 9 is used to encapsulate the iron nano-colloidal adsorbent. The tube wall of the hollow cylinder 9 is provided with a through hole 11, and the top of the hollow cylinder 9 is provided with a water inlet 12. The outer circumference of the filter membrane element 10 forms the water outlet surface of the filter membrane element.

[0059] The iron nano-colloidal adsorbent is placed in a hollow cylinder 9 to encapsulate a filter element 6 filled with liquid iron nano-colloidal adsorbent, so that acidic phosphorus-contaminated groundwater enters from the water inlet pipe 2, flows through the sand and gravel layer 4, the activated carbon layer 5, the filter element 6 filled with iron nano-colloidal adsorbent and the biofilm layer 7 in sequence, and finally flows out from the water outlet pipe 8, thereby achieving the removal of phosphorus in the acidic phosphorus-contaminated groundwater.

[0060] In a preferred embodiment of the present invention, the liquid iron nano-colloidal adsorbent is prepared by dissolving an iron nano-colloidal adsorbent in water.

[0061] In a preferred embodiment of the present invention, the acidic phosphorus-contaminated groundwater flows naturally by gravity or is introduced into the water inlet pipe by a water pump, preferably by natural flow.

[0062] In a preferred embodiment of the present invention, the flow rate of acidic phosphorus-contaminated groundwater is 0.33-1 mL / min.

[0063] In a preferred embodiment of the present invention, the dosage of the iron nano-colloidal adsorbent in the acidic phosphorus-contaminated groundwater is 1-2 g / 10-20 L, that is, 1-2 g of the iron nano-colloidal adsorbent is required to treat 10-20 L of acidic phosphorus-contaminated groundwater.

[0064] In a preferred embodiment of the present invention, the pH of the acidic phosphorus-contaminated groundwater is 3-4, preferably pH 3.

[0065] All raw materials used in the examples of the present invention are commercially available, and the particle size of FeOOH fine powder after screening is less than 0.6 mm.

[0066] In the embodiments of the present invention, "parts" represent "parts by weight" unless otherwise specified.

[0067] The technical solution of the present invention is further illustrated by the following embodiments.

[0068] Example 1

[0069] (1) Using FeOOH fine powder as an iron precursor, oleic acid as a stabilizer, and 1-octadecene as a solvent, the following components were weighed in parts by weight: 1.8 parts of FeOOH fine powder, 23 parts of oleic acid, and 50 parts of 1-octadecene;

[0070] FeOOH fine powder, oleic acid and 1-octadecene were mixed and stirred at 120 °C for 1 h to remove residual water;

[0071] Then the temperature was raised to 320 °C and the thermal decomposition reaction was carried out in an argon environment for 1 h;

[0072] After the reaction, the purified Fe 3 O4 Nanoparticles;

[0073] (2) Weigh the prepared purified Fe 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 10 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0074] The transmission electron microscope characterization image of the iron nanocolloid adsorbent prepared in Example 1 is shown in Figure 2 , it can be seen that Fe 3 O 4 The particle size is at the nanometer level, so it has strong adsorption properties.

[0075] Application Example 1

[0076] Application of iron nanocolloid adsorbent in phosphorus removal from acidic phosphorus-contaminated groundwater:

[0077] Acidic phosphorus-contaminated groundwater is simulated phosphorus-contaminated water, and the initial phosphorus concentration in the simulated phosphorus-contaminated water is 0-2200 mg / L.

[0078] At 25° C. and pH 3, 0.002 g of the iron nanocolloid adsorbent prepared in Example 1 was added into 10 mL of simulated phosphorus-contaminated water. During the treatment, the stirring speed was maintained at 70 rpm and the reaction time was set to 120 min.

[0079] In this application example, the adsorption kinetics of the iron nanocolloid adsorbent prepared in Example 1 to treat simulated phosphorus-contaminated water is shown in Figure 3 , it can be seen that the iron nanocolloid adsorbent exhibits significant adsorption capacity at different initial phosphorus concentrations. With the increase of initial phosphorus concentration, the adsorption capacity increases significantly. When the initial phosphorus concentration is 100 mg / L, the adsorption capacity is 712 mg / g; when the concentration increases to 2000 mg / L, the adsorption capacity reaches a maximum value of 9242 mg / g. This shows that the iron nanocolloid adsorbent can still maintain excellent adsorption performance in a high-concentration phosphorus environment. The significant improvement in adsorption capacity is mainly attributed to the high specific surface area and high reactivity of the nanocolloid. The PEI-modified iron nanoparticles can provide more adsorption sites, and the cationic properties of PEI enhance the adsorption capacity of anionic phosphates. This synergistic effect enables the nanocolloid to still efficiently adsorb phosphate in a high-concentration phosphorus environment.

[0080] Application Example 2

[0081] Acidic phosphorus-contaminated groundwater is actual phosphogypsum-contaminated (acidic) groundwater, and the initial phosphorus concentration in the phosphorus-contaminated water is 801.02 mg / L.

[0082] At 25°C and pH 3, 0.002 g of the iron nanocolloid adsorbent prepared in Example 1 was added to 10 mL of simulated phosphorus-contaminated water. During the treatment, the stirring speed was maintained at 70 rpm and the reaction time was set to 30 min. After adsorption, the iron nanocolloid adsorbent and the adsorbed phosphate were separated by filtration through an ultrafiltration device.

[0083] The iron nanocolloid adsorbent was collected and the above steps were repeated for 3 times.

[0084] In this application example, the effect diagram of the iron nano-colloid adsorbent prepared in Example 1 treating acidic phosphorus-contaminated groundwater is shown in Figure 4 It can be seen that within 5 minutes, the phosphate concentration dropped rapidly and the removal rate quickly increased to 82%, indicating that the adsorption speed was very fast; at 10 minutes, the removal rate rose to 89% and remained stable thereafter. This rapid and efficient adsorption effect verifies the application potential of iron nanocolloid adsorbent in ultrafast treatment of acidic phosphorus-contaminated groundwater. Iron nanocolloid adsorbent can significantly reduce the phosphorus concentration in acidic phosphorus-contaminated groundwater in a short time, showing excellent treatment performance.

[0085] In this application example, the reusability effect diagram of the iron nano-colloid adsorbent prepared in Example 1 for treating acidic phosphorus-contaminated groundwater is shown in Figure 5 (The horizontal axes 1, 2, and 3 represent the number of times the iron nanocolloidal adsorbent is reused). It can be seen that after the iron nanocolloidal adsorbent is recycled and treated three times, the removal rates are 92%, 89%, and 89%, respectively. The overall adsorption capacity is still relatively high, showing the application potential and stability of the iron nanocolloidal adsorbent in the ultrafast treatment of acidic phosphorus-contaminated groundwater.

[0086] Application Example 3

[0087] 0.002 g of the iron nano-colloid adsorbent prepared in Example 1 was dissolved in 10 mL of ultrapure water to obtain a liquid iron nano-colloid adsorbent, which was then packaged in a water purification device (see the schematic diagram of the structure). Figure 1 ) in the empty cylinder 9;

[0088] The water purification device is driven into the soil layer at the bottom of the water of phosphorus-contaminated acidic groundwater (source is phosphogypsum-contaminated (acidic) groundwater, with an initial phosphorus concentration of 801.02 mg / L and a pH of 3). The phosphorus-contaminated acidic groundwater naturally flows into the water inlet pipe 2 by gravity. The water inlet pipe 2 is adjusted so that the flow rate is 1 mL / min. The phosphorus-contaminated acidic groundwater enters from the water inlet pipe 2 at the top of the water purification device. The water filtered through the sandstone layer 4 flows into the activated carbon layer 5 along the shell. The water filtered through the activated carbon layer 5 flows from the shell into the filter element 6 filled with liquid iron nano-colloid adsorbent. The liquid iron nano-colloid adsorbent quickly adsorbs phosphorus in the water. The water is filtered by the filter element 10 of the filter element and flows out from the periphery through the through hole 11. After being treated by the microbial membrane layer 7, it is discharged through the discharge water pipe 8. The phosphorus precipitate collected by the water purification device can be used for farmland fertilization.

[0089] Comparative Example 1

[0090] Using FeOOH fine powder as an iron precursor, oleic acid as a stabilizer, and 1-octadecene as a solvent, the following components were weighed in parts by weight: 1.8 parts of FeOOH fine powder, 23 parts of oleic acid, and 50 parts of 1-octadecene;

[0091] FeOOH fine powder, oleic acid and 1-octadecene were mixed and stirred at 120 °C for 1 h to remove residual water;

[0092] Then the temperature was raised to 320 °C and the thermal decomposition reaction was carried out in an argon environment for 1 h;

[0093] After the reaction, the purified Fe 3 O 4 Nanoparticles, as adsorbents.

[0094] Comparative Example 2

[0095] An adsorbent includes polyethyleneimine (PEI).

[0096] Comparative Example 3

[0097] The same as Example 1, except that in step (2), the prepared purified Fe 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 38 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0098] Comparative Example 4

[0099] The same as Example 1, except that in step (2), the prepared purified Fe 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 2 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0100] Comparative Example 5

[0101] The same as Example 1, except that in step (1), the following components are weighed in parts by weight: 4 parts of FeOOH fine powder, 10 parts of oleic acid, and 30 parts of 1-octadecene.

[0102] Comparative Example 6

[0103] (1) Use of Fe 2 O 3 Fine powder is used as an iron precursor, oleic acid is used as a stabilizer, and 1-octadecene is used as a solvent. The following components are weighed in parts by weight: 1.8 parts of FeOOH fine powder, 23 parts of oleic acid, and 50 parts of 1-octadecene;

[0104] Fe 2 O 3 The fine powder, oleic acid and 1-octadecene were mixed and stirred at 120 °C for 1 h to remove residual water;

[0105] Then the temperature was raised to 320 °C and the thermal decomposition reaction was carried out in an argon environment for 1 h;

[0106] After the reaction, the purified Fe 3 O 4 Nanoparticles;

[0107] (2) Weigh the prepared purified Fe 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 10 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0108] Application Example 4

[0109] Acidic phosphorus-contaminated groundwater is actual phosphogypsum-contaminated (acidic) groundwater. The initial phosphorus concentration in the phosphorus-contaminated water is 801.02 mg / L and the pH value is 3.

[0110] At 25°C and pH 3, 0.002 g of the iron nanocolloid adsorbent prepared in Comparative Examples 1-6 was added to 10 mL of phosphorus-contaminated water. During the treatment, the stirring speed was maintained at 70 rpm and the reaction time was set to 30 min. After adsorption, the iron nanocolloid adsorbent and the adsorbed phosphate were separated by filtration through an ultrafiltration device.

[0111] In this application example, under the conditions of Comparative Example 1, Fe 3 O 4 Nanoparticles lack dispersants and will quickly aggregate into large particles in water and be oxidized, resulting in a reduction in specific surface area and loss of adsorption activity. 2 The amount is limited, and its ability to bind phosphate is much smaller than that of Fe 3 O 4 Nanoparticles. Under the conditions of Comparative Example 3, polyethyleneimine (PEI) was excessive, Fe 3 O 4 The adsorption sites of the particles were buried, and the binding with phosphate was inhibited. Under the conditions of Comparative Example 4, the content of polyethyleneimine (PEI) was insufficient, and Fe 3 O 4 The nanoparticles agglomerated into large particles, the specific surface area was reduced, and they were oxidized, and the adsorption activity was inhibited. Under the conditions of comparative example 5, the content of oleic acid and 1-octadecene was insufficient, the water could not be completely removed, and iron impurities containing crystal water were formed, and the adsorption activity was weaker than that of Fe 3 O 4 Nanoparticles. Under the conditions of Comparative Example 6, Fe 2 O 3 The material activity is weaker than FeOOH, the synthesized particle size is larger, the surface area is smaller, and the adsorption activity is smaller. Therefore, the effect efficiency of the iron nano-colloid adsorbent prepared in Comparative Examples 1 to Comparative Examples 6 in treating acidic phosphorus-contaminated groundwater is weaker than that in Example 1.

[0112] Example 2

[0113] (1) Using FeOOH fine powder as an iron precursor, oleic acid as a stabilizer, and 1-octadecene as a solvent, the following components were weighed in parts by weight: 2 parts of FeOOH fine powder, 30 parts of oleic acid, and 40 parts of 1-octadecene;

[0114] FeOOH fine powder, oleic acid and 1-octadecene were mixed and stirred at 150 °C for 1 h to remove residual water;

[0115] Then the temperature was raised to 400 °C and the thermal decomposition reaction was carried out in an argon environment for 1.5 h;

[0116] After the reaction, the purified Fe3 O 4 Nanoparticles;

[0117] (2) Weigh the prepared purified Fe according to the following weight parts: 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 15 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0118] Example 3

[0119] (1) Using FeOOH fine powder as an iron precursor, oleic acid as a stabilizer, and 1-octadecene as a solvent, the following components were weighed in parts by weight: 1 part of FeOOH fine powder, 20 parts of oleic acid, and 50 parts of 1-octadecene;

[0120] FeOOH fine powder, oleic acid and 1-octadecene were mixed and stirred at 80 °C for 1 h to remove residual water;

[0121] Then the temperature was raised to 300 °C and the thermal decomposition reaction was carried out in an argon environment for 1 h;

[0122] After the reaction, the purified Fe 3 O 4 Nanoparticles;

[0123] (2) Weigh the prepared purified Fe according to the following weight parts: 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 20 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0124] Example 4

[0125] (1) Using FeOOH fine powder as an iron precursor, oleic acid as a stabilizer, and 1-octadecene as a solvent, the following components were weighed in parts by weight: 2 parts of FeOOH fine powder, 28 parts of oleic acid, and 45 parts of 1-octadecene;

[0126] FeOOH fine powder, oleic acid, and 1-octadecene were mixed and stirred at 100 °C for 1 h to remove residual water;

[0127] Then the temperature was raised to 350 °C and the thermal decomposition reaction was carried out in an argon environment for 1 h;

[0128] After the reaction, the purified Fe 3 O 4 Nanoparticles;

[0129] (2) Weigh the prepared purified Fe according to the following weight parts: 3 O 4 Nanoparticles 1 part and polyethyleneimine (PEI) 18 parts, the purified Fe 3 O 4 The nanoparticles are mixed with polyethyleneimine (PEI) to prepare an iron nanocolloid adsorbent.

[0130] Application Example 5

[0131] Acidic phosphorus contaminated groundwater is phosphogypsum contaminated (acidic) groundwater. The initial phosphorus concentration in the phosphorus contaminated water is 801.02 mg / L and the pH value is 3.

[0132] At 25°C and pH 3, 0.002 g of the iron nanocolloid adsorbent prepared in Examples 2-4 was added to 10 mL of phosphorus-contaminated water. During the treatment, the stirring speed was maintained at 70 rpm and the reaction time was set to 30 min. After adsorption, the iron nanocolloid adsorbent and the adsorbed phosphate were separated by filtration through an ultrafiltration device.

[0133] In this application example, the effect of the iron nanocolloid adsorbent prepared in Examples 2-4 on treating acidic phosphorus-contaminated groundwater was close to that in Example 1. The results showed that within 5 minutes, the phosphate concentration dropped rapidly and the removal rate quickly increased to 79% at the lowest, indicating that the adsorption speed was very fast; at 10 minutes, the removal rate rose to 85% at the lowest and remained stable thereafter.

[0134] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An iron nanocolloid adsorbent, characterized in that: In terms of weight, the raw materials include 1 part of Fe3O4 nanoparticles and 10-20 parts of polyethyleneimine.

2. The iron nanocolloid adsorbent according to claim 1, characterized in that: The Fe3O4 nanoparticle raw material comprises the following components in parts by weight: 1-2 parts of FeOOH fine powder, 20-30 parts of oleic acid and 40-50 parts of 1-octadecene.

3. The iron nanocolloid adsorbent according to claim 2, characterized in that: The preparation method of the Fe3O4 nanoparticles comprises the following steps: FeOOH fine powder, oleic acid and 1-octadecene are weighed in parts by weight, mixed and stirred, and then heated in an argon environment for pyrolysis reaction. After the reaction is completed, purification is performed to obtain the Fe3O4 nanoparticles.

4. The iron nanocolloid adsorbent according to claim 3, characterized in that: The mixing and stirring is performed at a temperature of 80-150° C. and for a time of 1 hour.

5. The iron nanocolloid adsorbent according to claim 3, characterized in that: The temperature of the pyrolysis reaction is 300-400°C and the time is 1-1.5h.

6. The iron nanocolloid adsorbent according to claim 1, characterized in that: In terms of weight, the raw materials include 1 part of Fe3O4 nanoparticles and 10 parts of polyethyleneimine.

7. A method for preparing the iron nanocolloid adsorbent according to any one of claims 1 to 6, characterized in that: The following steps are involved: Fe3O4 nanoparticles and polyethyleneimine are weighed in parts by weight, and the two are mixed to obtain the iron nanocolloid adsorbent.

8. Use of the iron nanocolloid adsorbent according to any one of claims 1 to 6 in the treatment of acidic phosphorus-contaminated groundwater.

9. A method for removing phosphorus from acidic phosphorus polluted groundwater, characterized in that: The iron nano-colloid adsorbent according to any one of claims 1 to 6 is added to acidic phosphorus-contaminated groundwater, mixed and stirred to achieve the removal of phosphorus in the acidic phosphorus-contaminated groundwater.

10. A method for removing phosphorus from acidic phosphorus-contaminated groundwater, characterized in that: The iron nano-colloid adsorbent according to any one of claims 1 to 6 is used as a filter element of a water purification device, and acidic phosphorus-contaminated groundwater is allowed to flow through the water purification device to achieve phosphorus removal in the acidic phosphorus-contaminated groundwater.

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