Modified pelelith material for ecological floating island as well as preparation method and application of modified pelelith material

Abstract

The invention belongs to the technical field of eutrophic water purification treatment, and discloses a modified pelelith material for an ecological floating island as well as a preparation method and application of the modified pelelith material. The preparation method comprises the following steps: by taking inorganic acid liquid as a first modifier, completely immersing natural vesuvianite in the inorganic acid liquid, and carrying out oscillation treatment, so as to obtain primarily modified natural vesuvianite; alkali liquor is used as a second modifier, the preliminarily modified natural pelelith is completely immersed in the alkali liquor for immersion treatment, and the modified pelelith material is obtained. By adopting an acid-base synergistic modification mode, the adsorption performance of the pelelith can be remarkably improved, so that inorganic pollutants such as NH4 < + >-N, PO4 < 3->, fluorine ions and copper ions in a water body and organic pollutants such as levofloxacin can be purified; the modified pelelith material provided by the invention can be used as a matrix material for an ecological floating island, and purification treatment of various pollutants in eutrophicated water is realized.

Description

Technical Field

[0001] The invention relates to the technical field of eutrophic water purification and treatment, and in particular to a modified volcanic rock material for an ecological floating island and a preparation method and application thereof. Background Art

[0002] Bio-ecological restoration technology utilizes the absorption and degradation of nutrients during plant growth and relies on the metabolic activity of microorganisms to remove water pollutants. Among them, ecological floating island restoration technology has been widely used in many places due to its advantages such as simple structure, convenient management and green economy. The matrix and carrier in the ecological floating island are preferably made of polymer materials, and aquatic and terrestrial plants with well-developed root systems are planted in the matrix. Pollutants are removed through the physiological effects of plant roots and the biochemical reactions of microorganisms attached to them. The matrix has a significant impact on the purification efficiency of the ecological floating island, but different matrices have different chemical properties and physical structures. These properties enable different matrices to produce different adsorption effects on different pollutants. Therefore, selecting a suitable matrix and accurately identifying the target pollutants are the key to achieving the adsorption treatment goal.

[0003] Natural volcanic rocks and zeolites are expected to become the matrix materials for ecological floating islands due to their rough surfaces and rich pores. However, these natural minerals often contain a large amount of impurities in their surfaces and pore structures, which not only affects their ion exchange capacity, but also reduces the adsorption efficiency of target pollutants. Therefore, they need to be modified to improve their adsorption efficiency of target pollutants.

[0004] In order to solve the above technical problems, technicians in this field have proposed a variety of modification methods, such as using salt-based reagents to modify natural volcanic rocks, or using roasting combined with acid modification. Although the above modification methods can improve the adsorption performance of natural volcanic rocks to a certain extent, there are problems such as poor improvement effects and inability to meet actual use needs, or there are problems such as complex processes that are not conducive to promotion and large-scale use.

[0005] To this end, the present invention provides a modified volcanic rock material for an ecological floating island and a preparation method and application thereof. Summary of the invention

[0006] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a modified volcanic rock material for an ecological floating island and a preparation method and application thereof. The present invention uses natural volcanic rock as the matrix raw material of the ecological floating island, and modifies the natural volcanic rock by adopting an acid-base composite modification method to obtain a modified volcanic rock material that can be used for an ecological floating island.

[0007] The modified volcanic rock material for an ecological floating island of the present invention and its preparation method and application are realized by the following technical solutions:

[0008] The first purpose of the present invention is to provide a method for preparing a modified volcanic rock material for an ecological floating island. The present invention takes into account that natural volcanic rock has a unique honeycomb porous structure, its main component is SiO2, and contains minerals and rich trace elements, releases trace elements in the water body, and can adsorb harmful bacteria, heavy metals and residual chloride ions, and can adjust the pH value to increase the oxygen content. Therefore, the present invention preferably uses natural volcanic rock as the matrix raw material of the ecological floating island. In order to improve the adsorption performance of natural volcanic rock, the present invention modifies natural volcanic rock by adopting an acid-base composite modification method to obtain a modified volcanic rock material that can be used for an ecological floating island, and the specific preparation method of the modified volcanic rock material of the present invention includes the following steps:

[0009] Step 1: using an inorganic acid solution as a first modifier, completely immersing the natural volcanic rock in the inorganic acid solution for shaking treatment, so as to obtain a preliminarily modified natural volcanic rock.

[0010] It should be noted that the present invention takes into account that the presence of impurities such as silicon dioxide and various organic molecules in volcanic rocks not only affects the physical properties of volcanic rocks, but also may reduce their activity in the adsorption process. Therefore, the present invention preferably first uses inorganic acid as a modifier to modify the natural volcanic rocks, so as to effectively remove impurities such as silicon dioxide and various organic molecules from the volcanic rocks through inorganic acid modification, which is conducive to restoring the original adsorption activity of the volcanic rocks and improving their adsorption performance. In addition, inorganic acid can also dissolve those cationic impurities with larger diameters such as calcium and magnesium that were originally fixed in the pores. These cationic impurities often hinder the effective use of the pores and the adsorption efficiency. The present invention first uses acid modification to make H + It will replace larger diameter cations such as calcium and magnesium, thereby adjusting the structure of the volcanic rock and expanding the pore diameter, thereby improving the adsorption performance of the volcanic rock and obtaining preliminary modified natural volcanic rock.

[0011] In order to ensure that the inorganic acid solution used can achieve the modification treatment of natural volcanic rocks, in some preferred embodiments of the present invention, the inorganic acid in the inorganic acid solution used is one or more of sulfuric acid, hydrochloric acid and nitric acid, so as to ensure that the tiny impurity particles in the volcanic rocks can be effectively removed. These impurities usually include silicon dioxide and various organic molecules, etc., by dissolving the impurities originally fixed in the pores, H + It will replace larger diameter cations such as calcium and magnesium, restoring the original adsorption activity of the volcanic rock.

[0012] In order to avoid the problem that the inorganic acid solution concentration is insufficient, the complex pores in the natural volcanic rock cannot be deeply cleaned, and the modification effect on the natural volcanic rock cannot be fully achieved; and when the inorganic acid solution concentration is too high, the adsorption performance of the natural volcanic rock will not be further improved, and the inorganic acid solution will be wasted. Therefore, in some preferred embodiments of the present invention, the concentration of the inorganic acid in the inorganic acid solution used is 0.1mol / L to 1.5mol / L. In other preferred embodiments of the present invention, the inorganic acid solution used is a sulfuric acid solution, and the concentration of the sulfuric acid solution is 0.5mol / L to 1mol / L.

[0013] The present invention does not limit the specific amount of the inorganic acid solution, as long as the natural volcanic rock can be completely immersed so that the natural volcanic rock is fully in contact with the inorganic acid solution.

[0014] The present invention takes into account that the adsorption process is a typical endothermic reaction, and its main driving force lies in the formation and breaking of chemical bonds. At a certain modification temperature, the structure of the volcanic rock may change, thereby affecting the density and activity of its surface active sites, thereby enhancing the adsorption effect. In order to ensure that the inorganic acid solution can fully achieve the modification treatment of natural volcanic rock under a certain temperature adjustment, so that the inorganic acid solution is in full contact with the natural volcanic rock, the present invention found in the process of exploration that with the increase of the oscillation treatment temperature, the ability of the modified volcanic rock to remove nitrogen and phosphorus gradually increases. Since the increase in temperature has an enhancement effect on the Brownian motion of molecules, the H in the solution + The more intense the movement, the higher the contact efficiency between the adsorption point and the target pollutant. However, when the temperature rises to a certain level, the improvement effect is not obvious. Therefore, in some preferred embodiments of the present invention, the temperature of the oscillation treatment is 15°C to 35°C. In some more preferred embodiments of the present invention, the temperature of the oscillation treatment is 25°C to 30°C.

[0015] The present invention takes into account that the shaking time of the shaking treatment will also affect the modification effect of the inorganic acid on the volcanic rock. In order to ensure the modification effect of the shaking treatment on the volcanic rock, in some preferred embodiments of the present invention, the shaking time of the shaking treatment is 3h to 12h. In other preferred embodiments of the present invention, the shaking time of the shaking treatment is preferably 4h to 8h. In other preferred embodiments of the present invention, the shaking time of the shaking treatment is more preferably 5h to 7h.

[0016] The present invention takes into account that the vibration speed of the vibration treatment will also affect the modification effect of the inorganic acid solution on the volcanic rock. In order to ensure the modification effect of the vibration treatment on the volcanic rock, in some preferred embodiments of the present invention, the vibration speed of the vibration treatment is 150r / min to 250r / min. In other preferred embodiments of the present invention, the vibration speed of the vibration treatment is preferably 200r / min to 250r / min.

[0017] It is understandable that after the natural volcanic rock is treated with inorganic acid, inorganic acid may remain on its surface. In order to avoid affecting the subsequent alkaline solution treatment, the initially modified volcanic rock obtained after the inorganic acid treatment is repeatedly rinsed with distilled water to remove the inorganic acid remaining on the surface of the volcanic rock, and then the washed product is placed in an oven for drying to remove excess water to obtain dry initially modified volcanic rock.

[0018] It can also be understood that, since natural volcanic rocks will release nitrogen and phosphorus when they are directly used to repair and purify water bodies, natural volcanic rocks cannot be directly used for adsorption treatment of nitrogen and phosphorus wastewater. Therefore, in some preferred embodiments of the present invention, before immersing the natural volcanic rocks in inorganic acid solution, the natural volcanic rocks are also pretreated to effectively reduce the content of impurities such as nitrogen and phosphorus in the volcanic rocks, as well as suspended impurities and ash on the surface of the natural volcanic rocks, so as to obtain clean natural volcanic rocks. And in another effective embodiment of the present invention, the pretreatment is achieved by the following steps: the natural volcanic rocks are rinsed with distilled water several times to ensure that the suspended impurities and ash on the surface of the natural volcanic rocks are removed, and then dried to remove excess water, and then burned at 400°C to 650°C for 2h to 6h to effectively reduce the content of impurities such as nitrogen and phosphorus in the volcanic rocks, that is, to obtain clean natural volcanic rocks.

[0019] Step 2: using alkaline solution as a second modifier, completely immersing the natural volcanic rock preliminarily modified by the inorganic acid solution in the alkaline solution for immersion treatment, thereby obtaining the modified volcanic rock material.

[0020] It should be noted that, considering that the hydrogen bonds of volcanic rock minerals have greater binding force than other ores, the present invention preferably uses alkali solution as the second modifier. On the basis of the modification treatment with inorganic acid solution, the volcanic rock is further modified. The -OH in the alkali solution will react with the hydrogen bonds in the inner layer of the volcanic rock. This interaction weakens the original structural binding force inside the volcanic rock, thereby further improving the adsorption performance of the volcanic rock.

[0021] In order to ensure that the alkali solution used can achieve the above-mentioned modification effect, in some preferred embodiments of the present invention, the alkali solution used is one or more of a saturated sodium hydroxide solution, a potassium hydroxide solution and ammonia water. In some more preferred embodiments of the present invention, the alkali solution used is a saturated sodium hydroxide solution, and the concentration of the saturated sodium hydroxide solution is higher than that of the unsaturated solution, so the saturated sodium hydroxide solution can increase the reaction rate with the volcanic rock; and the saturated solution contains more sodium hydroxide molecules, so it may react with more components in the volcanic rock, thereby producing a more obvious modification effect, thereby achieving a faster reaction rate and a better modification effect through the saturated sodium hydroxide solution.

[0022] The present invention does not limit the specific amount of the alkali solution, as long as the natural volcanic stone can be completely immersed so that the natural volcanic stone is fully in contact with the alkali solution.

[0023] In order to ensure that the initially modified volcanic rock is modified by the alkali solution treatment, in some preferred embodiments of the present invention, the temperature of the immersion treatment is room temperature and the time is 8h to 24h.

[0024] It is understandable that since alkali may remain on the surface of the volcanic rock after being treated with alkali, in order to avoid affecting the subsequent effect of repairing and purifying water bodies, the modified volcanic rock obtained after the alkali treatment is first soaked and washed with distilled water until the pH value is stable to remove the alkali remaining on the surface of the volcanic stone, and then the washed product is placed in an oven for drying to remove excess moisture to obtain dry modified volcanic rock.

[0025] The second object of the present invention is to provide a modified volcanic rock material prepared by the above preparation method.

[0026] The third object of the present invention is to provide an application of the modified volcanic rock material in the preparation of ecological floating islands.

[0027] It should be noted that when preparing the ecological floating island, the modified volcanic rock material is used as the matrix material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention adopts the method of acid-base synergistic modification to significantly improve the adsorption performance of volcanic rock, so that it has excellent adsorption efficiency for various pollutants in water bodies, and can not only achieve the adsorption of NH4 + -N, PO4 3- It can not only purify inorganic pollutants such as fluoride ions and copper ions, but also purify organic pollutants such as levofloxacin in water bodies, so that it can be used as a matrix material for ecological floating islands to purify a variety of pollutants in eutrophic water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a photo of natural volcanic stone raw material.

[0031] Figure 2 The modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 react with NH4 + -N adsorption efficiency test results.

[0032] Figure 3 The modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 are used to treat PO4 3- The adsorption efficiency test results.

[0033] Figure 4 The modified volcanic rock obtained in Examples 1-5 is NH4 + -N adsorption efficiency test results.

[0034] Figure 5 The modified volcanic rock obtained in Examples 1-5 is used for PO4 3- The adsorption efficiency test results.

[0035] Figure 6 The modified volcanic rock obtained in Examples 6-10 is NH4 + -N adsorption efficiency test results.

[0036] Figure 7 The modified volcanic rock obtained in Examples 6-10 is PO4 3- The adsorption efficiency test results.

[0037] Figure 8 Modified volcanic rock to adsorb NH4 + -N isotherm fitting results.

[0038] Fig. 9 Modified volcanic rock to adsorb PO4 3- Isotherm fitting results.

[0039] Fig.10 These are photos of the on-site starvation culture of the test plants.

[0040] Fig.11 This is a photo of a floating island composed only of plants.

[0041] Fig.12 For ecological floating islands to treat NH4 in eutrophic water + -N's purification effect.

[0042] Fig.13 For ecological floating islands to treat PO4 in eutrophic water 3- purification effect. DETAILED DESCRIPTION

[0043] The technical solution in the embodiment of the present invention will be described clearly and completely below. It should be noted that the natural volcanic rock used in the present invention is purchased from Weifang, Shandong.

[0044] In order to explore the effect of the concentration of inorganic acid solution on the adsorption performance of the modified volcanic rock material finally prepared, the present invention provides the following embodiments:

[0045] Example 1

[0046] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0047] Step 1, pretreatment of natural volcanic stone:

[0048] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0049] Step 2, acid modification treatment:

[0050] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 0.1mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0051] Step 3, alkali modification treatment:

[0052] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0053] Example 2

[0054] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0055] Step 1, pretreatment of natural volcanic stone:

[0056] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0057] Step 2, acid modification treatment:

[0058] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 0.5mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0059] Step 3, alkali modification treatment:

[0060] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0061] That is, the difference between this embodiment and embodiment 1 is only that:

[0062] In this embodiment, the concentration of the sulfuric acid solution is 0.5 mol / L.

[0063] Example 3

[0064] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0065] Step 1, pretreatment of natural volcanic stone:

[0066] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0067] Step 2, acid modification treatment:

[0068] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 0.8mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0069] Step 3, alkali modification treatment:

[0070] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0071] That is, the difference between this embodiment and embodiment 1 is only that:

[0072] In this embodiment, the concentration of the sulfuric acid solution is 0.8 mol / L.

[0073] Example 4

[0074] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0075] Step 1, pretreatment of natural volcanic stone:

[0076] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0077] Step 2, acid modification treatment:

[0078] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0079] Step 3, alkali modification treatment:

[0080] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0081] That is, the difference between this embodiment and embodiment 1 is only that:

[0082] In this embodiment, the concentration of the sulfuric acid solution is 1.0 mol / L.

[0083] Example 5

[0084] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0085] Step 1, pretreatment of natural volcanic stone:

[0086] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0087] Step 2, acid modification treatment:

[0088] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.5mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0089] Step 3, alkali modification treatment:

[0090] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0091] That is, the difference between this embodiment and embodiment 1 is only that:

[0092] In this embodiment, the concentration of the sulfuric acid solution is 1.5 mol / L.

[0093] In order to explore the effect of the oscillation temperature on the adsorption performance of the modified volcanic rock material finally prepared, the present invention provides the following embodiments:

[0094] Example 6

[0095] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0096] Step 1, pretreatment of natural volcanic stone:

[0097] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0098] Step 2, acid modification treatment:

[0099] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a water bath at a constant temperature of 15°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0100] Step 3, alkali modification treatment:

[0101] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0102] Example 7

[0103] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0104] Step 1, pretreatment of natural volcanic stone:

[0105] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0106] Step 2, acid modification treatment:

[0107] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 20°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0108] Step 3, alkali modification treatment:

[0109] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0110] That is, the difference between this embodiment and embodiment 6 is only that:

[0111] In this embodiment, the temperature of the shaking treatment is 20°C.

[0112] Example 8

[0113] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0114] Step 1, pretreatment of natural volcanic stone:

[0115] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0116] Step 2, acid modification treatment:

[0117] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 25°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0118] Step 3, alkali modification treatment:

[0119] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0120] That is, the difference between this embodiment and embodiment 6 is only that:

[0121] In this embodiment, the temperature of the shaking treatment is 25°C.

[0122] Example 9

[0123] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0124] Step 1, pretreatment of natural volcanic stone:

[0125] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0126] Step 2, acid modification treatment:

[0127] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 30°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0128] Step 3, alkali modification treatment:

[0129] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0130] That is, the difference between this embodiment and embodiment 6 is only that:

[0131] In this embodiment, the temperature of the shaking treatment is 30°C.

[0132] Example 10

[0133] This embodiment provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0134] Step 1, pretreatment of natural volcanic stone:

[0135] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature forced air drying oven at 90°C for 12 hours. The dried product was then transferred to a resistance furnace and calcined at 500°C for 6 hours to obtain clean natural volcanic rock.

[0136] Step 2, acid modification treatment:

[0137] Take 10g of the clean natural volcanic rock obtained above and place it in 100mL of 1.0mol / L sulfuric acid solution, and shake it at a speed of 200r / min for 12h in a constant temperature water bath at 35°C. After the shaking, filter it, rinse the filter residue repeatedly with distilled water, and then dry it in an electric constant temperature blast drying oven at 90°C for 12h to obtain the preliminary modified natural volcanic rock.

[0138] Step 3, alkali modification treatment:

[0139] Take 10g of the preliminary modified natural volcanic rock obtained above and place it in 100mL of a saturated sodium hydroxide solution with a concentration of 4.5mol / L, and immerse it at room temperature for 12h. After sufficient reaction, the volcanic rock is soaked and washed with distilled water until the pH value of the solution is stable, filtered, and the filter residue is repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 6h to obtain modified volcanic rock.

[0140] That is, the difference between this embodiment and embodiment 6 is only that:

[0141] In this embodiment, the temperature of the shaking treatment is 35°C.

[0142] Comparative Example 1

[0143] This comparative example provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0144] The natural volcanic rock was rinsed with distilled water for several times to remove impurities on the surface, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours, and then the dried product was transferred to a resistance furnace and burned at 500°C for 6 hours to obtain clean natural volcanic rock. 10g of the clean natural volcanic rock obtained above was placed in 100mL of 0.5mol / L zinc chloride solution, and oscillated at a speed of 200r / min for 12 hours in a water bath at 20°C. After the oscillation, it was filtered, and the filter residue was repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours to obtain modified volcanic rock.

[0145] That is, the difference between this comparative example and Example 2 is only that:

[0146] In this comparative example, zinc chloride solution was used as a modifier for modification.

[0147] Comparative Example 2

[0148] This comparative example provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0149] The natural volcanic rock was rinsed with distilled water several times to remove impurities on the surface, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours, and then the dried product was transferred to a resistance furnace and burned at 500°C for 6 hours to obtain clean natural volcanic rock. 10g of the clean natural volcanic rock obtained above was placed in 100mL of 0.5mol / L ferric chloride solution, and oscillated at a speed of 200r / min for 12 hours in a water bath at 20°C. After the oscillation, it was filtered, and the filter residue was repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours to obtain modified volcanic rock.

[0150] That is, the difference between this comparative example and Example 2 is only that:

[0151] In this comparative example, ferric chloride solution was used as a modifier for modification.

[0152] Comparative Example 3

[0153] This comparative example provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0154] The natural volcanic rock was rinsed with distilled water several times to remove impurities on the surface, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours, and then the dried product was transferred to a resistance furnace and burned at 500°C for 6 hours to obtain clean natural volcanic rock. 10g of the clean natural volcanic rock obtained above was placed in 100mL of 0.5mol / L sulfuric acid solution, and oscillated at a speed of 200r / min for 12 hours in a water bath at 20°C. After the oscillation, it was filtered, and the filter residue was repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours to obtain modified volcanic rock.

[0155] That is, the difference between this comparative example and Example 2 is only that:

[0156] In this comparative example, only sulfuric acid solution is used as a modifier for modification treatment.

[0157] Comparative Example 4

[0158] This comparative example provides a method for preparing a modified volcanic rock material for an ecological floating island, comprising the following steps:

[0159] The natural volcanic rock was rinsed with distilled water several times to remove impurities on the surface, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours, and then the dried product was transferred to a resistance furnace and burned at 500°C for 6 hours to obtain clean natural volcanic rock. 10g of the clean natural volcanic rock obtained above was placed in 100mL of 0.5mol / L sodium hydroxide solution, and oscillated at a speed of 200r / min for 12 hours in a water bath at 20°C. After the oscillation, it was filtered, and the filter residue was repeatedly rinsed with distilled water, and then dried in an electric constant temperature blast drying oven at 90°C for 12 hours to obtain modified volcanic rock.

[0160] That is, the difference between this comparative example and Example 2 is only that:

[0161] In this comparative example, only sodium hydroxide solution is used as a modifier for modification treatment.

[0162] Comparative Example 5

[0163] This comparative example uses natural volcanic rock raw materials that have not been treated in any way as a blank control, and its photo is as follows Figure 1 shown.

[0164] Experimental Section

[0165] The nitrogen and phosphorus wastewater used in this experiment is simulated ammonia nitrogen wastewater and simulated phosphate wastewater prepared by NH4Cl crystals and potassium dihydrogen phosphate KH2PO4. The specific configuration method is as follows:

[0166] 1) Dissolve 3.819 g of analytically pure NH4Cl crystals dried at 105°C for 2 hours in an appropriate amount of distilled water and dilute to volume in a 1000 mL volumetric flask. The concentration of the standard stock solution is 1000 mg / L. Take an appropriate amount of the stock solution and dilute it to the pre-used concentration to obtain the desired concentration of simulated ammonia nitrogen wastewater.

[0167] 2) Dissolve 1.433 g of analytically pure KH2PO4 crystals dried at 105°C for 2 hours in an appropriate amount of distilled water and dilute to volume in a 1000 mL volumetric flask. The concentration of the standard stock solution is 1000 mg / L. Take an appropriate amount of the stock solution and dilute it to the pre-used concentration to obtain the desired concentration of simulated phosphate wastewater.

[0168] (I) Adsorption performance test of modified volcanic rock

[0169] Considering the convenience of testing, the following adsorption performance tests are all conducted with NH4 + -N and PO4 3- As a target pollutant, NH4 + -N, PO4 3- The adsorption efficiency is used to evaluate the adsorption performance of modified volcanic rock. And the adsorption performance test is carried out by static adsorption test.

[0170] 1) Effects of different modification methods on the adsorption properties of volcanic rocks

[0171] The present invention takes the modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 as examples, and tests the modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 on NH4 + -N, PO4 3- The adsorption efficiency of volcanic rocks was analyzed to analyze the effect of different modification methods on the adsorption performance of volcanic rocks. The test results are as follows: Figure 2 and Figure 3 shown.

[0172] Figure 2 The modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 react with NH4 + -N adsorption efficiency test results. Figure 2 By comparing Comparative Example 5 with Comparative Example 1 and Comparative Example 2, it can be seen that when inorganic salt is used as a modifier, the adsorption performance of natural volcanic rock can be improved to a certain extent, but the modification effect is limited and cannot meet the requirements of efficient removal of pollutants. And the modified volcanic rock of Comparative Example 1 has a low adsorption rate for NH4 + The removal rate of -N was 36.50%, and the modified volcanic rock of Example 2 had a significant effect on NH4 + The removal rate of -N was 25.75%. The adsorption effect of comparative example 1 was better than that of comparative example 2. This may be due to the fact that the zinc ions were loaded on the surface of the volcanic rock, which enhanced the adsorption of NH4 +-N adsorption capacity. However, FeCl3 is prone to produce Fe(OH)3 precipitation after hydrolysis, which leads to blockage of the pore structure on the surface of volcanic rock, and thus cannot effectively improve the adsorption performance of volcanic rock.

[0173] Figure 2 By comparing the test results of Example 2, Comparative Example 3 and Comparative Example 4, it can be seen that the modified volcanic rock of Comparative Example 3 has a significant effect on NH4 + The removal rate of -N was 28.75%, and the modified volcanic rock of Example 4 had a significant effect on NH4 + The removal rate of -N was 44.75%, while the modified volcanic rock obtained by acid-base synergistic modification had a significant effect on NH4 + The removal rate of -N can reach 56.15%, and the adsorption capacity can reach 2.24 mg / g, which shows that the acid-base synergistic modification method adopted in the present invention will not cause acid-base neutralization and reduce the improvement effect, but will significantly improve the adsorption performance of volcanic rock.

[0174] Figure 3 The modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 are used to treat PO4 3- The adsorption efficiency test results. Figure 3 It can be seen that the modified volcanic rocks obtained in Example 2 and Comparative Examples 1-5 have a higher PO4 3- The adsorption efficiency of the mineral material has been improved. The improvement effect of Example 2 is the best, and the improvement effect of Comparative Example 2 is the second. Among them, Comparative Example 2 may be due to the generation of Fe2O3·H2O containing iron oxides. These particles are attached to the mineral adsorbent, which can greatly improve the adsorption performance of the mineral material. The acid-base synergistic modification method of the present invention can significantly improve the volcanic rock's PO4 compared to the modification of a single acid or base in Comparative Examples 3 and 4. 3- This may be due to the fact that acid-base synergistic modification can more effectively remove impurities and more comprehensively adjust the surface chemical properties of volcanic rocks, including the types and quantities of functional groups, surface charge distribution, etc., thus improving the adsorption efficiency of PO4 3- It can provide more and more suitable binding sites for the adsorption of PO4; it may synergistically improve the pore structure of volcanic rocks, form more abundant micropores, mesopores and macropores, increase the specific surface area and pore volume of adsorption, and be beneficial to the adsorption of PO4 3- diffusion and adsorption.

[0175] 2) Effect of different inorganic acid concentrations on the adsorption properties of volcanic rocks

[0176] The present invention takes the modified volcanic rocks obtained in Examples 1-5 as examples, and tests the modified volcanic rocks obtained in Examples 1-5 on NH4 + -N, PO4 3-The adsorption efficiency of volcanic rocks was analyzed to analyze the effect of different inorganic acid concentrations on the adsorption performance of volcanic rocks. The test results are as follows: Figure 4 and Figure 5 shown.

[0177] Figure 4 The modified volcanic rock obtained in Examples 1-5 is NH4 + -N adsorption efficiency, it can be seen that when the sulfuric acid concentration is 0.1mol / L, the modified volcanic rock has a strong adsorption capacity for NH4 + -N removal rate is 24%, and the corresponding adsorption capacity is 0.96mg / g. At this time, the sulfuric acid concentration is low, and the improvement effect on adsorption performance is limited. As the sulfuric acid concentration increases, the modified volcanic rock adsorbs NH4 + -N capacity first gradually increases and then tends to be stable, indicating that when the sulfuric acid concentration increases to 1.5 mol / L, the improvement effect on the adsorption performance will not be further improved. For this reason, the preferred inorganic acid concentration of the present invention is 0.1-1.5 mol / L, and more preferably 0.5-1 mol / L.

[0178] Figure 5 The modified volcanic rock obtained in Examples 1-5 is used for PO4 3- The adsorption efficiency of Figure 4 Similarly, it means that when the concentration of the inorganic acid solution is too low, the adsorption performance cannot be effectively improved, and when the concentration of the inorganic acid solution is too high, the improvement effect will not be further improved. Therefore, the preferred concentration of the inorganic acid solution in the present invention is 0.1-1.5 mol / L, and more preferably 0.5-1 mol / L.

[0179] 3) Effect of different oscillation temperatures on the adsorption performance of volcanic rocks

[0180] The present invention takes the modified volcanic rocks obtained in Examples 6-10 as examples, and tests the modified volcanic rocks obtained in Examples 6-10 on NH4 + -N, PO4 3- The adsorption efficiency of volcanic rocks was analyzed to analyze the effect of different oscillation temperatures on the adsorption performance of volcanic rocks. The test results are as follows: Figure 6 and Figure 7 shown.

[0181] Figure 6 The modified volcanic rock obtained in Examples 6-10 is NH4 + -N adsorption efficiency, it can be seen that when the oscillation temperature is 15℃, the modified volcanic rock has a high adsorption efficiency for NH4 + -N removal rate is 23.5%. At this time, the temperature is low, and it is difficult to effectively enhance the Brownian motion of molecules, so the improvement effect on adsorption performance is limited. As the oscillation temperature increases, the modified volcanic rock adsorbs NH4 +The ability of -N gradually increases and then tends to be stable, and when the oscillation temperature is increased to 35°C, the improvement effect on the adsorption performance tends to be stable. Therefore, the preferred oscillation temperature of the present invention is 25-35°C.

[0182] Figure 7 The modified volcanic rock obtained in Examples 6-10 is PO4 3- The adsorption efficiency of Figure 6 Similarly, it means that when the oscillation temperature is too low, the adsorption performance cannot be effectively improved, and when the oscillation temperature is too high, the improvement effect will not be further improved. Therefore, the preferred oscillation temperature of the present invention is 25-35°C.

[0183] (II) Analysis of adsorption mechanism

[0184] The present invention treats simulated ammonia nitrogen and phosphate wastewater with concentrations of 10mg / L, 20mg / L, 40mg / L, 60mg / L, 80mg / L, and 100mg / L, respectively. 10g of acid-base composite modified volcanic rock is added to a 250mL conical flask, the oscillator speed is set to 200r / min, and adsorption is performed for 3h at 10℃, 20℃, and 30℃. After the adsorption reaches equilibrium, the adsorption amount of ammonia nitrogen and phosphate ions in the solution and the corresponding adsorption capacity are calculated. The test results obtained by the above tests are fitted using the Langmuir and Freundlich adsorption isotherm models, and the fitting results are as follows: Figure 8 and Fig. 9 shown.

[0185] Figure 8 Modified volcanic rock to adsorb NH4 + -N isotherm fitting results, and according to Figure 8 The fitting results show that the fitting correlation coefficients of the two isotherm models are R 2 are all above 0.9. Specifically, the Langmuir adsorption isotherm R 2 The values ​​are higher than Freundlich, indicating that the Langmuir adsorption isotherm model is more suitable for the modified volcanic rock to NH4 + The description of the -N adsorption process is more accurate.

[0186] According to the Langmuir adsorption isotherm model, NH4 + -N adsorption mainly occurs at the binding sites inside the volcanic rock. These binding sites not only + -N molecules closely correspond to each other, and there is a one-to-one correspondence between these positions. This adsorption mechanism is a chemical adsorption process based on a monolayer. And from the Langmuir adsorption isotherm fitting parameters, it can be seen that volcanic rocks have a strong affinity for NH4 +The absorption capacity of -N increases with the increase of temperature. The test results show that at the adsorption temperature of 30℃, the modified volcanic rock adsorbs NH4 + The theoretical maximum value of -N can reach 3.43 mg / g.

[0187] Fig. 9 Modified volcanic rock to adsorb PO4 3- The isotherm fitting results, and according to Fig. 9 The fitting results show that as the concentration of phosphorus-containing wastewater simulated in the experiment continues to increase, the modified volcanic rock material has a positive effect on PO4 3- The adsorption capacity of the modified volcanic rock was significantly enhanced. This change was specifically reflected at the microscopic level. After precise measurement and data analysis, it was found that the surface of the modified volcanic rock could accumulate more PO4 3- molecules, and its adsorption amount also increases accordingly. In the process of constructing the adsorption model, through statistical analysis of the measured phosphorus adsorption, it can be clearly seen that more points are consistent with the fitting curve of the Freundlich model, indicating that the model has a good fit. Comparing the measured values ​​with the signals that can be captured by the Freundlich model, it can be inferred that there is a relatively consistent correlation between the two. And the fitting correlation coefficients of the two models are both higher than 0.95, indicating that both can accurately describe the modified volcanic rock for PO4 3- adsorption characteristics.

[0188] Specifically, this modified volcanic rock is effective in adsorbing PO4 3- The process presents a complex interaction pattern, which includes the adsorption of single molecular layers and multi-molecular layers. These molecular layers form a multi-level structure on the surface of the adsorbent. The adsorption sites on the surface of modified volcanic rock are unevenly distributed, and there is a coexistence of uniformity and inhomogeneity. These uneven adsorption sites may be caused by differences in the pore structure inside the adsorbent or by differences in the surface chemical properties. In addition, the two types of adsorption processes, physical adsorption based on electrostatic attraction and chemical adsorption based on ion exchange, occur simultaneously. They influence each other and jointly determine the modified volcanic rock adsorbent for PO4 3- adsorption behavior.

[0189] In summary, the modified volcanic rock material prepared by the present invention has a good + -N and PO4 3- In addition, the present invention has found in the further exploration process that the modified volcanic rock material prepared by the present invention also has excellent adsorption efficiency for other inorganic pollutants such as fluoride ions and copper ions, as well as organic pollutants such as levofloxacin, indicating that the modified volcanic rock material prepared by the present invention can be used as a matrix material for ecological floating islands to achieve purification of various pollutants in eutrophic water bodies.

[0190] (III) Application of modified volcanic rocks in ecological floating island systems

[0191] The modified volcanic rock prepared in Example 9 and oyster shell were mixed in a volume ratio of 1:1 to obtain a mixture as a matrix material, and cattail and calamus were used as aquatic plants, respectively. The matrix material and the aquatic plants were combined using the following method to repair and purify eutrophic water bodies.

[0192] The present invention adds NH4Cl and KH2PO4 to tap water to simulate eutrophic water. The NH4 + -N, PO4 3- concentrations, as shown in Table 1. T1, T2, and T3 are floating island combinations of plants and modified volcanic rocks, and Z1, Z2, and Z3 are floating island combinations of only plants.

[0193] Table 1 Configuration of water bodies with different eutrophication levels

[0194] combination Ammonia nitrogen (mg / L) Phosphate (mg / L) Eutrophication level T1 / Z1 2.014 1.501 Mild T2 / Z2 4.059 4.037 Moderate T3 / Z3 8.094 5.516 Severe

[0195] Before the experiment, the plant roots were cleaned and the test plants were starved for 3 days in a 1 mol / L CaSO4·2H2O solution. Fig.10 As shown. The test culture container is a 28.5cm×23cm×50cm transparent glass box, which can treat 20L of sewage. Three cattails and calamus, trimmed to 35cm in height, are placed in each floating island basin. The above-prepared matrix material is placed in a floating island basin with a specification of 150, and XPS extruded board is used to float in the test water. A floating island with only plant combination is set as a control group, as shown in FIG. Fig.11 The test started in mid-July 2023, and water samples were collected every 2 days to measure the nitrogen and phosphorus concentrations in the water. The test period was 15 days. The test results were as follows: Fig.12 and Fig.13 shown.

[0196] Fig.12 Ecological floating islands to treat NH4 in eutrophic water + -N purification effect, it can be seen that in the first 1-6 days, the NH4 + -N concentrations decreased rapidly, and then the NH4 + -N concentration tends to be flat, while T3 combination NH4 + -N concentration further decreased and stabilized after 8 days. + -N removal rates were 80.58%, 80.39% and 84.60% respectively. In the later tests, due to the NH4 +-N concentration continued to be low, and the ability of plant roots to absorb nitrogen was significantly weakened, affecting the rate at which plants acquire nitrogen nutrients. After 8 days, NH4 + -N was completely consumed. During the experiment, only the Z1, Z2, and Z3 floating islands of the plant combination had NH4 + The -N concentration showed a fluctuating downward trend, and the removal rate was only 62.06% to 71.07% at the end of the experiment, which was significantly lower than that of the treatment group with a combination of plants and substrates.

[0197] The floating island composed of plants and modified volcanic rocks in the present invention has an effect on the removal of NH4 + The removal effect of -N was better than that of the control group with only plants, and the higher the eutrophication degree of the water body, the better the pollutant removal effect. This is because the oxygen produced by plant photosynthesis is transferred to the rhizosphere, forming an aerobic and anoxic environment around the plant roots, and the microorganisms play a nitrification oxidation role to convert NH4 + -N is converted to NO3 - -N, thus quickly purifying the water. The microorganisms in the T category group can use the plant roots and the substrate in the floating island basin as attachment carriers, multiply in large numbers and exert biochemical functions. Compared with the Z category group, they are more sensitive to NH4 + -N removal rate is nearly 20% higher. It can be seen that the present invention can achieve the removal of NH4 in eutrophic water by combining the prepared modified volcanic rock with plants. + -N plays a purifying role.

[0198] Fig.13 For ecological floating islands to treat PO4 in eutrophic water 3- The purification effect of T2 and T3 can be seen from the following table: 3- The concentration of PO4 decreases rapidly, and in 8-10 days 3- The concentration has basically reached a stable state. The PO4 3- The concentration reached a low level on the 4th day. At the end of the experiment, the T1, T2, and T3 ecological floating islands had a significant effect on PO4 3- The removal rates were 75.68%, 81.35% and 83.79% respectively.

[0199] At the beginning of the experiment, the plants were in a state of phosphorus starvation, which prompted them to quickly absorb phosphorus from the water to meet their basic needs for growth and reproduction. As the experiment progressed, the PO4 3- The concentration gradually decreases until it reaches a critical point. At this point, plants begin to use a more complex active transport mechanism to absorb phosphorus. This process not only causes multiple biochemical reactions, but also causes the rate at which plants absorb phosphorus to slow down accordingly. Plants initially mainly obtain phosphorus through passive absorption, but when PO4 3-When the concentration reaches the critical point, it must consume its own energy to achieve reverse concentration absorption. This change is one of the important strategies for plants to adapt to environmental pressure and improve their survival ability. However, the removal rate of phosphorus by plant roots is not constant, but is significantly affected by the phosphorus concentration in the culture solution. The efficiency of plant phosphorus removal increases with the increase of pollutant concentration, indicating that plants have enhanced adaptability to environmental pollution.

[0200] Z-type floating island PO4 with only plant combinations 3- The concentration dropped slowly compared to the T-type floating island, and the final removal rate was only 54.43% to 56.18%. 3- Removal mainly relies on the absorption and precipitation of plants.

[0201] In summary, the ecological floating island composed of plants and substrates can better purify PO4 in water. 3- Compared with floating islands that only plant plants, the removal rate is nearly 25% higher, and the PO4 in the water is consumed by plants themselves. 3- The effect is not ideal.

[0202] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for preparing modified volcanic rock materials for ecological floating islands, characterized in that: The following steps are involved: Using an inorganic acid solution as a first modifier, completely immersing the natural volcanic stone in the inorganic acid solution for shaking treatment, thereby obtaining a preliminarily modified natural volcanic stone; The modified volcanic stone material is obtained by using alkali solution as the second modifier and completely immersing the preliminarily modified natural volcanic stone in the alkali solution for immersion treatment.

2. The preparation method according to claim 1, characterized in that The inorganic acid in the inorganic acid solution is one or more of sulfuric acid, hydrochloric acid and nitric acid; The concentration of the inorganic acid in the inorganic acid solution is 0.1 mol / L to 1.5 mol / L.

3. The preparation method according to claim 1, characterized in that: The alkali solution is one or more of saturated sodium hydroxide solution, saturated potassium hydroxide solution and ammonia water.

4. The preparation method according to claim 1, characterized in that: The shaking temperature of the shaking treatment is 15°C to 35°C.

5. The preparation method according to claim 1, characterized in that: The shaking time of the shaking treatment is 3h to 12h.

6. The preparation method according to claim 1, characterized in that: The shaking speed of the shaking treatment is 150r / min to 250r / min.

7. The preparation method according to claim 1, characterized in that: The immersion treatment is carried out at room temperature for 8 to 24 hours.

8. A modified volcanic rock material prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the modified volcanic rock material according to claim 8 in preparing an ecological floating island.

10. The use according to claim 9, characterized in that The modified volcanic stone material is used as the matrix material.

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