Adsorbing material for recovering phosphorus, preparation method and application of adsorbing material in fertilizer aspect
By using adsorbent materials prepared by clay mineral modified biomass, the existing problems of high cost and environmental pollution of phosphorus recovery materials are solved, and the efficient adsorption of phosphorus and use it for fertilizers is achieved to promote crop growth.
Patent Information
- Application Number
- CN202411313867.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2024-12-24
AI Technical Summary
The existing adsorbent materials for recovering phosphorus are costly and dissolving metal ions during use cause secondary pollution of the environment, and the recovered phosphorus is not effectively utilized.
Using clay minerals as modifiers, by adding water and clay minerals to the biomass, drying and pyrolysis treatment, a recovered phosphorus adsorption material with high adsorption properties is prepared and used in fertilizers.
The prepared adsorbent materials are low in cost and have high adsorption properties. The adsorbed phosphorus can be used in fertilizers to promote crop growth and solve the problems of environmental friendliness and resource utilization.
Smart Images
Figure CN119175076A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of adsorption materials and recycling, and in particular to an adsorption material for recovering phosphorus, a preparation method and application thereof in fertilizers. Background Art
[0002] Phosphorus is a non-renewable resource. How to efficiently recover phosphorus (such as phosphorus in phosphates) from eutrophic water bodies and utilize it has become a hot topic in current research. However, traditional adsorption materials for recovering phosphorus have problems such as low adsorption capacity, high cost, and secondary environmental pollution caused by the dissolution of metal ions during use, and the recovered phosphorus is not effectively utilized. Therefore, finding a low-cost and environmentally friendly high-performance adsorption material is an urgent problem to be solved.
[0003] At present, biochar is a commonly used material for adsorbing and regulating phosphorus in the environment. However, biochar prepared by conventional methods has a weak adsorption effect on phosphate. Although studies have shown that surface modification of biochar with metal ion modifiers such as iron, magnesium and lanthanum can significantly increase its adsorption of phosphorus, the added modifiers will cause secondary pollution to the environment on the one hand, and increase the cost of preparing adsorption materials on the other.
[0004] In summary, it is necessary to develop an adsorption material for recovering phosphorus, a preparation method and its application in fertilizers to solve the problems of high cost and secondary environmental pollution caused by the dissolution of metal ions during use of existing adsorption materials for recovering phosphorus, and the failure to effectively utilize the recovered phosphorus. Summary of the invention
[0005] The present invention aims to provide an adsorption material for recovering phosphorus, a preparation method and its application in fertilizers. The specific technical scheme is as follows:
[0006] In a first aspect, the present invention provides a method for preparing an adsorption material for recovering phosphorus, comprising:
[0007] Step S1, adding water and a modifier to the biomass, mixing, and then centrifuging to obtain a prefabricated solid; the modifier includes a clay mineral;
[0008] Step S2, subjecting the prefabricated solid to drying and pyrolysis treatments in sequence to obtain a prefabricated adsorption material; and subjecting the prefabricated adsorption material to post-treatment to obtain an adsorption material for recovering phosphorus.
[0009] Optionally, the clay mineral includes at least one of attapulgite, sepiolite and illite.
[0010] Optionally, the biomass is agricultural and forestry waste biomass, which includes at least one of jute straw, tobacco straw and tea residue.
[0011] Optionally, in step S1, the mass ratio of the modifier to the biomass is 1:1-1:3.
[0012] Optionally, in step S2, the drying process adopts a drying temperature of 80-105° C. and a drying time of 24-48 hours.
[0013] Optionally, in step S2, the pyrolysis treatment is performed under an inert atmosphere, the pyrolysis temperature used is 600-700°C, and the insulation time is 2-4h.
[0014] Optionally, in step S2, the post-treatment includes cooling the prefabricated adsorption material to room temperature and then grinding it through a 100-mesh sieve to obtain an adsorption material for recovering phosphorus.
[0015] In a second aspect, the present invention provides an adsorption material for recovering phosphorus, which is prepared by the preparation method of the adsorption material for recovering phosphorus.
[0016] In a third aspect, the present invention provides an application of the phosphorus recovery adsorption material in adsorbing and recovering phosphorus.
[0017] Optionally, the adsorbent material that adsorbs and recovers phosphorus is used as a fertilizer for crops.
[0018] The application of the technical solution of the present invention has at least the following beneficial effects:
[0019] The present invention provides an adsorption material for recovering phosphorus, a preparation method and an application thereof in fertilizers. The modifier used includes clay minerals. On the one hand, the clay minerals are low in cost and have large specific surface area, abundant pores, strong cation exchange capacity and adjustable surface charge. These characteristics endow the clay minerals with very ideal cheap and environmentally friendly adsorption materials. The clay minerals contain a large number of nano-sized pores, and the clay minerals contain Lewis acids and Acid sites, when they combine with polar oxygen in the organic matter of biomass pyrolysis, change the bond length and bond energy of -CC- and -CO, resulting in the breaking of the charge balance of the original structure, which is beneficial to the pyrolysis of biomass into valuable chemical intermediates and porous biochar;
[0020] On the other hand, clay minerals are rich in elements such as calcium, sodium, magnesium, iron and aluminum, which can not only provide the necessary trace elements for the growth of crops, but also regulate the surface structure of biochar (changing the surface electrical properties, specific surface area and surface functional groups of biochar, etc.) to improve its adsorption performance for phosphate; in addition, the nano-scale porous structure of clay minerals can effectively improve and alleviate soil compaction, increase soil porosity, and improve soil water retention capacity. Therefore, the adsorption material for recovering phosphorus prepared by the present invention using clay mineral modified biomass belongs to a green and environmentally friendly adsorption material, which is not only low in cost and has high adsorption performance for phosphorus, but also the adsorption material itself and the adsorbed and recovered phosphorus can be used as fertilizer to promote the growth and development of crops.
[0021] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0023] Figure 1 This is a scanning electron microscope test image of the adsorption material prepared in Example 4;
[0024] Figure 2 This is the EDS spectrum analysis diagram of the adsorption material prepared in Example 4;
[0025] Figure 3 The test results of the adsorption material prepared in Example 4 on phosphorus-containing wastewater with gradient dosage;
[0026] Figure 4 Comparison of the adsorption of phosphorus in phosphorus-containing wastewater with different pH values by the adsorbent material prepared in Example 4;
[0027] Figure 5 is the adsorption amount of phosphorus by the adsorption material at different times and the kinetic fitting curve;
[0028] Figure 6 The effect of the adsorption material prepared in Example 4 on the growth of mung beans after adsorbing different concentrations of phosphorus;
[0029] Figure 7 Fourier infrared spectra of the adsorption material prepared in Example 4 before and after adsorption of phosphorus-containing wastewater;
[0030] Figure 8 The XPS total spectra of the adsorption material prepared in Example 4 before and after adsorption of phosphorus-containing wastewater;
[0031] Fig. 9 The XPS carbon spectra of the adsorption material prepared in Example 4 before and after adsorption of phosphorus-containing wastewater;
[0032] Fig.10 XPS magnesium spectra of the adsorption material prepared in Example 4 before and after adsorption of phosphorus-containing wastewater;
[0033] Fig.11 These are the XPS aluminum spectra of the adsorption material prepared in Example 4 before and after adsorption of phosphorus-containing wastewater. DETAILED DESCRIPTION
[0034] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.
[0035] Embodiment 1:
[0036] A method for preparing an adsorption material for recovering phosphorus, comprising:
[0037] Step S1, adding water and a modifier to the biomass, mixing, and then centrifuging (the centrifugal treatment is completed in a centrifuge, the centrifuge speed is controlled to be 4000r / min, and the centrifugation time is controlled to be 10min) to obtain a prefabricated solid; the modifier includes clay minerals, specifically attapulgite; the biomass is agricultural and forestry waste biomass, specifically tea residues; the mass ratio of the modifier to the biomass is 1:3;
[0038] Step S2, subjecting the prefabricated solid to drying and pyrolysis treatments in sequence to obtain a prefabricated adsorption material; and subjecting the prefabricated adsorption material to post-treatment to obtain an adsorption material for recovering phosphorus.
[0039] In step S2, the drying process adopts a drying temperature of 105° C. and a drying time of 24 hours.
[0040] In step S2, the pyrolysis treatment is carried out under an inert atmosphere (nitrogen atmosphere, nitrogen flow rate is 250 mL / min), the pyrolysis temperature is 600°C, and the holding time is 2 hours.
[0041] In step S2, the post-treatment includes cooling the prefabricated adsorption material to room temperature and then grinding it through a 100-mesh sieve to obtain an adsorption material for recovering phosphorus.
[0042] Embodiment 2:
[0043] Different from Example 1, in step S1, the mass ratio of the modifier to the biomass is 1:1.
[0044] Embodiment 3:
[0045] Different from Example 1, in step S1, the mass ratio of the modifier to the biomass is 1:2.
[0046] Embodiment 4:
[0047] Different from Example 1, in step S2, the pyrolysis temperature adopted is 700°C.
[0048] Comparative Example 1:
[0049] Different from Example 1, in step S1, the mass ratio of the modifier to the biomass is 1:0.5.
[0050] Comparative Example 2:
[0051] Different from Example 1, in step S1, the mass ratio of the modifier to the biomass is 1:4.
[0052] Comparative Example 3:
[0053] Different from Example 1, in step S1, the amount of biomass used is zero.
[0054] Comparative Example 4:
[0055] Different from Example 1, in step S1, the amount of the modifier used is zero.
[0056] Comparative Example 5:
[0057] Different from Example 1, in step S2, the pyrolysis temperature adopted is 500°C.
[0058] Comparative Example 6:
[0059] Different from Example 1, in step S2, the pyrolysis temperature adopted is 800°C.
[0060] 0.1 g of the adsorption materials prepared in Examples 1-4 and Comparative Examples 1-6 were respectively sampled to complete the adsorption test of phosphorus in phosphorus-containing wastewater, and the test results are shown in Table 1. The phosphorus-containing wastewater is a potassium dihydrogen phosphate aqueous solution, and the initial phosphorus concentration is 20 mg / L. The adsorption test method is as follows: the sample is added to 50 mL of phosphorus-containing wastewater, adsorbed for 80 minutes at 25°C, then passed through a membrane, developed color, and the residual phosphorus concentration in the phosphorus-containing wastewater is determined; the adsorption rate of phosphorus by different samples is calculated according to the initial phosphorus concentration and the residual concentration.
[0061] Table 1 Phosphorus adsorption data of different samples
[0062] Grouping Adsorption rate (%) Example 1 (mass ratio of modifier to biomass is 1:3, pyrolysis temperature is 600°C) 84.5 Example 2 (mass ratio of modifier to biomass is 1:1, pyrolysis temperature is 600°C) 50.7 Example 3 (mass ratio of modifier to biomass is 1:2, pyrolysis temperature is 600°C) 52.6 Example 4 (mass ratio of modifier to biomass is 1:3, pyrolysis temperature is 700°C) 100 Comparative Example 1 (mass ratio of modifier to biomass is 1:0.5, pyrolysis temperature is 600°C) 18.4 Comparative Example 2 (mass ratio of modifier to biomass is 1:4, pyrolysis temperature is 600°C) 79.2 Comparative Example 3 (mass ratio of modifier to biomass is 1:0, pyrolysis temperature is 600°C) 21.6 Comparative Example 4 (mass ratio of modifier to biomass is 0:3, pyrolysis temperature is 600°C) 5.9 Comparative Example 5 (mass ratio of modifier to biomass is 1:3, pyrolysis temperature is 500°C) 46.4 Comparative Example 6 (mass ratio of modifier to biomass is 1:3, pyrolysis temperature is 800°C) 66.5
[0063] From the data in Table 1, it can be seen that compared with Comparative Examples 1-6, the present invention adopts Examples 1-4, that is, controlling the mass ratio of the modifier to the biomass to 1:1-1:3 and controlling the pyrolysis temperature to 600-700° C. to prepare an adsorption material with a higher phosphorus adsorption rate. This shows that the preparation method of Examples 1-4 can prepare an adsorption material with a larger specific surface area and a richer pore structure, thereby improving the adsorption rate of phosphorus.
[0064] The adsorption materials prepared in Example 4 were sampled for scanning electron microscopy and EDS energy spectrum analysis. Figure 1 This is a scanning electron microscope test image of the adsorption material prepared in Example 4, which shows that the adsorption material has a rich pore structure. Figure 2 This is the EDS energy spectrum analysis diagram of the adsorption material prepared in Example 4. It can be seen that the adsorption material is rich in elements such as magnesium, aluminum, and calcium, which provide active sites for the adsorption of phosphorus. Specifically, elements such as magnesium, aluminum, and calcium form complexes with phosphates to achieve the adsorption and removal of phosphorus.
[0065] The adsorption material prepared in Example 4 was subjected to a gradient dosage test on phosphorus-containing wastewater to verify the optimal dosage of the adsorption material for completely adsorbing phosphorus in phosphorus-containing wastewater. The test results are shown in Figure 3 The gradient dosage test method is as follows: add the adsorbent materials in gradient dosage to equal amounts of phosphorus-containing wastewater (the phosphorus-containing wastewater is potassium dihydrogen phosphate aqueous solution, and the initial concentration of the phosphorus-containing wastewater is 20 mg / L), so that the concentrations of the adsorbent materials in the phosphorus-containing wastewater are 0.25 g / L, 0.5 g / L, 0.75 g / L, 1.0 g / L, 1.25 g / L, 1.5 g / L, 1.75 g / L, 2.0 g / L, 2.25 g / L, 2.5 g / L, 2.75 g / L, 3.0 g / L, 3.25 g / L, 3.5 g / L, 3.75 g / L and 4.0 g / L, respectively. After adsorption for 80 minutes at 25°C, pass through the membrane, develop color and determine the residual phosphorus concentration in the phosphorus-containing wastewater; calculate the adsorption rate of phosphorus by the adsorbent materials in gradient dosage according to the initial phosphorus concentration and the residual phosphorus concentration.
[0066] Depend on Figure 3 It is known that when the concentration of the adsorbent in phosphorus-containing wastewater is 1.25 g / L, all phosphorus in the phosphorus-containing wastewater can be adsorbed and removed.
[0067] The adsorption material prepared in Example 4 was taken in equal amounts, each sample was 0.05 g, and added to phosphorus-containing wastewater of different pH values (the phosphorus-containing wastewater was potassium dihydrogen phosphate aqueous solution, and the initial concentration of the phosphorus-containing wastewater was 20 mg / L) to complete the phosphorus adsorption test. The test results are shown in Figure 4 The test method is as follows: prepare 50 mL of phosphorus-containing wastewater with a pH value of 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 respectively; add 0.05 g of adsorption material to the phosphorus-containing wastewater at each pH value, shake and react at room temperature for 80 minutes, and determine the remaining phosphorus concentration in the supernatant; calculate the adsorption rate of phosphorus by the adsorption material based on the initial phosphorus concentration and the remaining phosphorus concentration.
[0068] Depend on Figure 4 It is known that when the pH value of phosphorus-containing wastewater is 3-7, the adsorption rate of phosphorus by the adsorbent material is relatively high, while when the pH value of phosphorus-containing wastewater is 8-12, the adsorption rate of phosphorus by the adsorbent material decreases slightly. This shows that phosphorus-containing wastewater is more conducive to the adsorption of phosphorus by the adsorbent material under acidic to neutral conditions; in terms of the working principle, because the isoelectric point of the adsorbent material prepared in Example 4 is 7.3, in the acidic to neutral pH range, the surface of the adsorbent material is positively charged, and it can adsorb negatively charged phosphate by electrostatic action; under alkaline conditions, the surface of the adsorbent material is negatively charged, and phosphate is also negatively charged, and the mutual electrostatic repulsion leads to a decrease in the amount of phosphorus adsorption.
[0069] 0.05 g of the adsorption material prepared in Example 4 was added to 50 mL of phosphorus-containing wastewater (the phosphorus-containing wastewater was a potassium dihydrogen phosphate aqueous solution, and the initial concentration of the phosphorus-containing wastewater was 20 mg / L). The phosphorus-containing wastewater was shaken at room temperature, and the amount of phosphorus adsorbed by the adsorption material at different times was measured. The amount of phosphorus adsorbed by the adsorption material at different times and the kinetic fitting curves are shown in FIG. Figure 5 .Depend on Figure 5 It can be seen that within the first 40 minutes, the amount of phosphorus adsorbed by the adsorbent material is Q t It increases rapidly with the extension of time; the increase of adsorption gradually slows down within 40-80 minutes, and finally tends to equilibrium. This shows that the adsorption equilibrium time of the adsorbent material for phosphorus is relatively fast, that is, the adsorption equilibrium can be reached within 80 minutes. The first kinetic model (Pseudo-first-order model) and the second-order kinetic model (Pseudo-second-order model) were fitted respectively, and it was found that the adsorption of phosphorus by the adsorbent material conforms to the pseudo-second-order kinetic model, indicating that the adsorption of phosphorus by the adsorbent material is mainly chemical adsorption.
[0070] The application of the adsorption material prepared in Example 4 in the adsorption and recovery of phosphorus is as follows:
[0071] Take multiple equal samples of the adsorption material prepared in Example 4, 0.1 g of each sample, and add them into phosphorus-containing wastewater (phosphorus-containing wastewater is potassium dihydrogen phosphate aqueous solution) with different initial concentrations of C0 (0 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L and 50 mg / L), shake the phosphorus-containing wastewater at room temperature until the sample is adsorbed for 80 minutes, then take out the sample; add each sample into a culture cup filled with 10 g of quartz sand, stir to mix Evenly; add 3 germinated mung beans to each culture cup (germination method: first sterilize the mung beans with 70% alcohol, then use distilled water to wash away the alcohol remaining on the surface of the mung beans, scatter the mung bean seeds into a 10cm×10cm culture dish, add distilled water, and germinate at 30℃ for 12h), put the culture cup into a constant temperature incubator (culture temperature 25℃, light 12h / day) and culture for 8 days, measure the growth status of the mung beans, and record the plant height (Plant Height) and root length (Root Height). The results are as follows Figure 6 shown.
[0072] Depend on Figure 6 It is known that when adsorbent materials with different concentrations of phosphorus are added, the height of mung bean plants increases from 10.98cm to 14.54cm, and the root length increases from 5.3cm to 13.1cm; as the initial phosphorus concentration of phosphorus-containing wastewater increases, the amount of phosphorus adsorbed by the adsorbent material also increases, and the root system of mung bean grows significantly; among them, the root system of mung bean in the adsorbent material after adsorbing phosphorus-containing wastewater with an initial concentration of 40mg / L develops best, and the root length of mung bean in the adsorbent material without adsorbed phosphorus increases by 147%. It can be seen that the phosphorus recovered after adsorption is expected to be used as fertilizer to promote the growth and development of crops.
[0073] The adsorption material prepared in Example 4 in Table 1 was used to sample phosphorus-containing wastewater before and after adsorption, and Fourier transform infrared spectroscopy analysis was performed. The results are shown in Figure 7 .Depend on Figure 7 Know, at 1634cm -1 、1612cm -1 and 3455cm -1 The obvious absorption peak at 3455cm is caused by the stretching vibration of interlayer water and hydroxyl groups in the adsorbent material, and after adsorption, it is located at 3455cm -1 The -OH stretching frequency at 1634 cm is higher than that before adsorption, indicating that -OH may have entered the interlayer of the adsorbent material. -1 The hydroxyl peak at red-shifted after adsorption, indicating that -OH also participated in the adsorption process and may have ligand exchange with phosphorus. Figure 7 It can also be seen that before adsorption, the -1 、678cm -1 and 792cm -1There are stretching vibrations belonging to Mg-O or Al-O at 1106cm -1 and 1440cm -1 The new PO vibration peak appears at , which further indicates that phosphorus is adsorbed on the surface of the adsorbent material through precipitation or complexation.
[0074] The adsorption material prepared in Example 4 in Table 1 was sampled before and after adsorption of phosphorus-containing wastewater for XPS analysis. The results are shown in Figure 8-Figure 11 .Depend on Figure 8 It is known that after the adsorption material adsorbs phosphorus, a peak of P appears at 133.9eV, indicating that phosphorus is successfully adsorbed. Fig. 9 It is known that the P peak after the adsorption of phosphorus by the adsorbent material can be divided into three components, namely PO4 3- 、HPO4 2- and H2PO4 - The peaks of phosphate indicate that phosphate is adsorbed by the adsorbent material in these three forms. Figure 10-11 It is known that after the adsorption material adsorbs phosphorus, the peak areas at 1305.80 eV (belonging to the Mg-OH peak) and 74.6 eV (belonging to the Al-OH peak) are greatly reduced compared with those before adsorption, which may be due to ligand exchange between P and -OH.
[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for preparing an adsorbent material for recovering phosphorus, characterized in that: include: Step S1, adding water and a modifier to the biomass, mixing, and then centrifuging to obtain a prefabricated solid; the modifier includes a clay mineral; Step S2, subjecting the prefabricated solid to drying and pyrolysis treatments in sequence to obtain a prefabricated adsorption material; and subjecting the prefabricated adsorption material to post-treatment to obtain an adsorption material for recovering phosphorus.
2. The method for preparing the adsorbent material for recovering phosphorus according to claim 1, characterized in that: The clay mineral includes at least one of attapulgite, sepiolite and illite.
3. The method for preparing the adsorbent material for recovering phosphorus according to claim 1, characterized in that: The biomass is agricultural and forestry waste biomass, which includes at least one of jute straw, tobacco straw and tea residue.
4. The method for preparing a phosphorus recovery adsorbent material according to claim 1, characterized in that: In step S1, the mass ratio of the modifier to the biomass is 1:1-1:
3.
5. The method for preparing a phosphorus recovery adsorbent material according to claim 1, characterized in that: In step S2, the drying process adopts a drying temperature of 80-105°C and a drying time of 24-48 hours.
6. The method for preparing a phosphorus recovery adsorption material according to claim 1, characterized in that: In step S2, the pyrolysis treatment is performed under an inert atmosphere, the pyrolysis temperature used is 600-700°C, and the insulation time is 2-4h.
7. The method for preparing a phosphorus recovery adsorbent material according to claim 1, characterized in that: In step S2, the post-treatment includes cooling the prefabricated adsorption material to room temperature and then grinding it through a 100-mesh sieve to obtain an adsorption material for recovering phosphorus.
8. An adsorbent material for recovering phosphorus, characterized in that: The phosphorus recovery adsorption material is prepared by the preparation method of the phosphorus recovery adsorption material according to any one of claims 1 to 7.
9. Use of the phosphorus recovery adsorption material as claimed in claim 8 in the aspect of phosphorus recovery by adsorption.
10. The use according to claim 9, characterized in that: The adsorbent material that adsorbs and recovers phosphorus is used as fertilizer for crops.