Lanthanum modified phosphorus adsorbent and application thereof

Abstract

The invention provides a lanthanum-modified phosphorus adsorbent, and belongs to the technical field of water treatment adsorption materials. The preparation method comprises the following steps: collecting rainwater pipeline dredging sludge, grinding, drying and sieving; then pyrolyzing under a continuous nitrogen condition and a temperature condition of 800 DEG C to obtain a phosphorus adsorbent; and adding the obtained phosphorus adsorbent into a LaCl3 solution, stirring until the mixture is uniformly mixed, then adding a NaOH solution, adjusting the pH value of the solution to 8-12, stirring until the mixture is uniformly mixed, standing for a preset time, and carrying out suction filtration and drying to obtain the lanthanum modified phosphorus adsorbent. The main raw material of the prepared lanthanum-modified phosphorus adsorbent is rainwater pipeline sludge which is easy to obtain, the preparation process is simple, and the adsorbing capacity of phosphate is high. During application, the lanthanum-modified phosphorus adsorbent is placed in the accommodating device and then put, so that the condition that the adsorbent is completely covered by bottom mud of a water body and the adsorption efficiency is influenced can be avoided, and the adsorbent is convenient to recycle and replace.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment adsorption materials, and in particular relates to a lanthanum-modified phosphorus adsorbent and application thereof. Background Art

[0002] Phosphate is a common pollutant. Excessive phosphate in natural water bodies, wastewater and industrial wastewater can lead to eutrophication of water bodies, triggering algae proliferation, affecting water quality and the health of the ecosystem. Phosphorus adsorbents are widely used in water treatment systems and can effectively remove phosphates from water bodies. At present, in order to recycle the sludge produced by industrial production and life, it can be fired into ceramsite as a phosphorus adsorbent, and in order to further improve the adsorption effect of the prepared phosphorus adsorbent, the phosphorus adsorbent will also be modified. For example, the application document with publication number CN110871050 A discloses a method for the application and preparation of a lanthanum-modified ecological filler adsorbent, which uses sludge carbon slag and fly ash as basic raw materials to prepare ceramsite and fire it as a phosphorus adsorbent, and the ceramsite is placed in a lanthanum chloride solution for modification to improve its adsorption effect on phosphate. The modified ceramsite needs to be added to 5 mg / L, 200 mL phosphate solution to achieve a phosphate removal rate of more than 90%. It can be seen that the adsorption of phosphate by each gram of modified ceramsite is still relatively low, below 0.2 mg / g. Although some phosphorus adsorbents prepared from sludge have relatively high adsorption of phosphate, they require a mixture of multiple materials and the preparation process is relatively complicated. Therefore, it is necessary to provide a phosphorus adsorbent with a simple raw material source and preparation process, which can realize the resource utilization of sludge and has a relatively high adsorption capacity of phosphate. Summary of the invention

[0003] In order to solve the above-mentioned defects of the prior art, the present application provides a lanthanum-modified phosphorus adsorbent and its application. The main raw material for the prepared lanthanum-modified phosphorus adsorbent is only rainwater pipe sludge. The raw material is easy to obtain, the preparation process is simple, and the adsorption capacity of phosphate is relatively high.

[0004] In order to achieve the above object, the present invention adopts the following technologies: A lanthanum-modified phosphorus adsorbent, the preparation method comprising: S100, collecting sludge from the rainwater pipes, grinding and drying it, filtering it through a sieve, and then storing it in a drying cabinet; S200, pyrolyzing the rainwater pipe ditch sludge treated in step S100 under continuous nitrogen conditions and a temperature of 800° C. to obtain a phosphorus adsorbent; S300, adding the phosphorus adsorbent obtained in step S200 to the LaCl3 solution and stirring until the mixture is uniformly mixed, then adding the NaOH solution dropwise and stirring until the mixture is uniformly mixed, then adjusting the pH of the solution to 8-12 and stirring until the mixture is uniformly mixed, and finally standing for a preset time; S400, after filtration and drying, a lanthanum-modified phosphorus adsorbent is obtained.

[0005] Furthermore, in step S300, the mass concentration of the LaCl 3 solution is 5 g / L-30 g / L, and the mass of the phosphorus adsorbent added to every 100 mL of the LaCl 3 solution is 5 g.

[0006] Furthermore, the mass concentration of the LaCl3 solution in step S300 is 20 g / L.

[0007] Furthermore, the concentration of the NaOH solution added in step S300 is 2 mol / L, the amount of the NaOH solution added is 3 ml per 100 mL of LaCl 3 solution, and when adjusting the pH of the solution, the pH of the solution is adjusted to 10.

[0008] Further, in step S300, the phosphorus adsorbent obtained in step S200 is added to the LaCl3 solution and stirred for 2 hours, then the NaOH solution is added dropwise and stirred for 16 hours, the pH of the solution is adjusted to 8-12 and stirred for 6 hours, and finally allowed to stand for 24 hours.

[0009] The invention discloses an application of a lanthanum-modified phosphorus adsorbent, which comprises adding the lanthanum-modified phosphorus adsorbent into a phosphate-containing body.

[0010] Furthermore, the lanthanum-modified phosphorus adsorbent is placed in a containing device and then put into the phosphorus-containing water body. The containing device includes a pair of rectangular plates connected in a cross shape, and a pair of rectangular grooves are symmetrically provided on the rectangular plates to accommodate the lanthanum-modified phosphorus adsorbent. A filter is provided on both sides of the rectangular groove to block the lanthanum-modified phosphorus adsorbent and for water exchange.

[0011] Furthermore, a first strip groove is opened upwardly at the bottom of one rectangular plate to separate a pair of rectangular grooves thereon, and a second strip groove is opened downwardly at the top of the other rectangular plate to separate a pair of rectangular grooves (101) thereon, for connecting the two rectangular plates to form a cross shape, and a receiving groove is opened on both sides of the second strip groove, and a slider is slidably arranged in the receiving groove, and the inward end of the slider is connected to one end of a spring, and the other end of the spring is connected to the rectangular plate, and the outward end of the slider has an inclined surface with the bottom inclined toward the slider on the opposite side, and when the spring is in a natural position When in the state, the inclined surface is in the accommodating groove, a limiting groove is provided at the top of the first strip groove, when the two rectangular plates are connected to form a cross shape through the first strip groove and the second strip groove, the sliders are all in the limiting grooves, a pair of third strip grooves are opened on one side of a rectangular plate with an accommodating groove, the pair of third strip grooves are respectively connected with the two accommodating grooves, and the two sliders are provided with protrusions, and the two protrusions are respectively located in a pair of third strip grooves, when the spring is in the natural state, the distance between the end of the third strip groove away from the second strip groove and the protrusion is greater than the length of the slider protruding from the accommodating groove.

[0012] The beneficial effects of the present invention are: 1. The main raw material of the prepared lanthanum-modified phosphorus adsorbent is only rainwater pipe sludge. The raw material is easy to obtain, the preparation process is simple, and the adsorption capacity of phosphate is relatively high, which provides an effective strategy for the resource utilization of rainwater pipe ditch sludge and the convenient acquisition of high-adsorption phosphorus removal adsorbents.

[0013] 2. The optimal solution of this application can increase the adsorption capacity of phosphate by the new adsorbent obtained after lanthanum modification to more than twice that before modification, and the adsorption effect is significantly increased and the modification effect is obvious.

[0014] 3. The pH conditions under which the lanthanum-modified phosphorus adsorbent produces the best adsorption effect and the concentration of the lanthanum-modified phosphorus adsorbent in the water body corresponding to the phosphate concentration were determined.

[0015] 4. The adsorbent is placed in a containing device before being put into the water body, which can prevent the adsorbent from being completely covered by the bottom mud of the water body, thereby affecting the adsorption efficiency. The containing device can also be quickly disassembled for easy transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the elemental analysis diagram of the phosphorus adsorbent La-800N in this application.

[0017] Figure 2 This is a diagram showing the adsorption effects of different dosages of the phosphorus adsorbent La-800N in this application.

[0018] Figure 3This is the adsorption effect diagram of the phosphorus adsorbent La-800N in this application under different pH conditions and the ZATA potential diagram.

[0019] Figure 4 This is a graph showing the changes in total phosphorus (TP) concentration in water bodies with and without the addition of the phosphorus adsorbent La-800N described in this application during field experiments.

[0020] Figure 5 In the field experiment, the phosphorus adsorbent La-800N in this application and the sulfate (PO4 3- ) concentration variation diagram.

[0021] Figure 6 It is a stereoscopic diagram of the overall structure of the containing device in this application.

[0022] Figure 7 This is a structural stereogram of the two rectangular plates in the containing device of the present application after being separated.

[0023] Figure 8 for Figure 7 Enlarged view of part A in the middle.

[0024] Fig. 9 It is a partial structural stereogram of the containing device in this application.

[0025] Fig.10 It is a cross-sectional view of the containing device in this application.

[0026] Fig.11 for Fig.10 Magnified view of part B in .

[0027] Figure numerals: rectangular plate -1, filter screen -2, slider -3, spring -4, rectangular groove -101, first strip groove -102, second strip groove -103, accommodating groove -104, limiting groove -105, third strip groove -106, inclined surface -301, protrusion -302. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the implementation modes of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] The present invention provides a lanthanum-modified phosphorus adsorbent, the preparation steps of which include: S100, collecting the sludge from the rainwater pipe ditch, grinding and drying it, filtering it through a sieve, and then storing it in a drying cabinet; S200, pyrolyzing the sludge from the rainwater pipe ditch treated in step S100 to obtain a phosphorus adsorbent; S300, adding the phosphorus adsorbent obtained in step S200 to a LaCl3 solution and stirring it until it is evenly mixed, then adding a NaOH solution dropwise and stirring it until it is evenly mixed, then adjusting the pH of the solution to 8-12 and stirring it until it is evenly mixed, and finally standing it for a preset time; S400, obtaining a lanthanum-modified phosphorus adsorbent after suction filtration and drying.

[0030] The following describes in detail a method for preparing a lanthanum-modified phosphorus adsorbent provided by the present invention through multiple examples.

[0031] Example 1 (1) Collect the sludge from the rainwater pipes, place and grind it, dry it in an oven at 60°C to constant weight, then filter the resulting dried product through a 100-mesh sieve, store it in a drying cabinet, and mark and seal it.

[0032] (2) The rainwater pipe ditch sludge treated in the above steps was pyrolyzed in a tubular furnace under continuous nitrogen conditions. The initial temperature of the tubular furnace was set to 20°C, the heating rate was 5°C / min, and it was maintained at 800°C for 2 hours. The pyrolyzate obtained was used as an adsorbent and named 800N.

[0033] (3) Take 5 g of 800N and add it to 100 mL of 20 g / L LaCl3 solution, then stir it with a magnetic stirrer for 2 h, then adjust the pH to 4, stir it with a magnetic stirrer for 6 h, and let it stand for 24 h.

[0034] (4) After filtration and drying for 16 hours, a lanthanum-modified phosphorus adsorbent was obtained.

[0035] Example 2 (1) Collect the sludge from the rainwater pipes, place and grind it, dry it in an oven at 60°C to constant weight, then filter the resulting dried product through a 100-mesh sieve, store it in a drying cabinet, and mark and seal it.

[0036] (2) The rainwater pipe ditch sludge treated in the above steps was pyrolyzed in a tubular furnace under continuous nitrogen conditions. The initial temperature of the tubular furnace was set to 20°C, the heating rate was 5°C / min, and it was maintained at 800°C for 2 hours. The pyrolyzate obtained was used as an adsorbent and named 800N.

[0037] (3) Take 5 g of 800N and add it to 100 mL of 20 g / L LaCl3 solution, then stir it with a magnetic stirrer for 2 h, then add 1 mL of 2 mol / L NaOH solution dropwise, stir it with a magnetic stirrer for 16 h, then adjust the pH to 6, stir it with a magnetic stirrer for 6 h, and let it stand for 24 h.

[0038] (4) After filtration and drying for 16 hours, a lanthanum-modified phosphorus adsorbent was obtained.

[0039] Example 3 The steps are the same as those in Example 2, except that the amount of NaOH solution added in step (3) is adjusted to 2 mL and the pH is adjusted to 8.

[0040] Example 4 The steps are the same as those in Example 2, except that the amount of NaOH solution added in step (3) is adjusted to 3 mL and the pH is adjusted to 10.

[0041] Example 5 The steps are the same as those in Example 2, except that the amount of NaOH solution added in step (3) is adjusted to 5 mL and the pH is adjusted to 12.

[0042] Example 6 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 5 g / L.

[0043] Example 7 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 10 g / L.

[0044] Example 8 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 15 g / L.

[0045] Example 9 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 20 g / L.

[0046] Example 10 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 25 g / L.

[0047] Embodiment 11 The steps are the same as those in Example 4, except that the mass concentration of the LaCl3 solution in step (3) is adjusted to 30 g / L.

[0048] 0.25 g of each of the lanthanum-modified phosphorus adsorbents prepared in Examples 1 to 5 was added to 100 ml of a phosphate solution having a mass concentration of 50 mg / L and a pH of 6. The phosphorus adsorption results measured after 24 hours are shown in Table 1.

[0049] Table 1 Example Example 1 Example 2 Example 3 Example 4 Example 5 NaOH drop amount (ml) 0 1 2 3 5 pH was adjusted to 4 6 8 10 12 Phosphorus adsorption (mg) 3.55 3.67 3.88 4.05 3.95 From the data in Table 1, it can be seen that the phosphorus adsorption amount is the highest when 3 ml of NaOH is added and the pH is adjusted to 10 after stirring.

[0050] 0.25 g of the lanthanum-modified phosphorus adsorbent prepared in Examples 6 to 11 and the unmodified phosphorus adsorbent 800N were respectively put into 100 ml of a phosphate solution with a mass concentration of 50 mg / L and a pH of 6. The phosphorus adsorption results measured after 24 hours are shown in Table 2, where the LaCl3 mass concentration of 0 represents the unmodified phosphorus adsorbent 800N.

[0051] Table 2 Example / Comparative Example Comparative Example Example 6 Example 7 Example 8 Example 9 Example 10 Embodiment 11 <![CDATA[Mass concentration of LaCl3 (g / L)]]> 0 5 10 15 20 25 30 Phosphorus adsorption (mg) 1.73 2.24 2.77 3.12 3.88 3.91 3.95 From the data in Table 2, it can be seen that the adsorption amount of phosphorus by 800N modified by lanthanum at the LaCl3 mass concentration of 5g / L to 20g / L is continuously increasing. When the LaCl3 mass concentration is 255g / L and 30g / L, the adsorption amount of phosphorus by 800N modified by lanthanum is not significantly increased. Considering the adsorption effect and the economy of the preparation process, the LaCl3 mass concentration of 20g / L is selected. Therefore, the preparation method of lanthanum modified phosphorus adsorbent prepared according to the preparation method of Example 9 is the best preparation method, and the lanthanum modified phosphorus adsorbent prepared according to the preparation method of Example 9 is named La-800N.

[0052] Figure 1 The EDS graph of La-800N was presented, and the results showed that La-800N mainly contained elements such as C, O, Si and some Fe and La elements, proving that lanthanum was successfully loaded onto the surface of 800N, and no heavy metal elements harmful to the human body such as arsenic, lead and cadmium were found. Compared with some phosphorus adsorbents prepared from industrial sludge, it has a wider range of applications.

[0053] In order to evaluate the effect of La-800N dosage on phosphate adsorption performance, experimental tests were conducted at dosages of 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L, and 3 g / L. The phosphate concentration of phosphorus-containing wastewater used in the experiment was 50 mg / L, the pH of the phosphorus-containing wastewater was 6, and the adsorption time was 24 hours. The experimental results are as follows Figure 2As shown in the figure, it can be seen that increasing the amount of La-800N within a certain range provides more adsorption active sites, and the phosphate adsorption efficiency is significantly improved within a certain range. When the amount of La-800N reaches a certain value, too much adsorbent leads to the appearance of idle adsorption sites, which leads to a decrease in adsorption efficiency and a waste of resources. Figure 3 It can be seen that when La-800N is added at a rate of 2.5 g / L, the removal rate of phosphate reaches 90%, tends to be stable, and the adsorption amount reaches 17.46 mg / g. Considering the adsorption effect and economy, the optimal amount is 2.5 g / L.

[0054] In order to evaluate the effect of solution pH on the adsorption performance of phosphate, the adsorption effect of La-800N was tested experimentally under pH conditions of 4-11. The phosphate concentration of phosphorus-containing wastewater used in the experiment was still 20 mg / L, and La-800N was added at a rate of 1 g / L. The experimental results are shown in Figure 2. Figure 3 As shown in the figure, when the pH is 4 and 5, La-800N has the best adsorption effect on phosphate, with adsorption amounts of 18.49 mg / g and 18.57 mg / g, and removal rates of 95.2% and 95.6%, respectively. When the pH is between 6 and 10, the removal rate is between 85% and 95%. When the pH is adjusted from 10 to 11, the adsorption effect decreases significantly, with the adsorption amount and removal rate dropping to 13.09 mg / g and 64.55%, respectively. Figure 3 The relationship between the pH of the phosphate solution and the Zeta potential of the La-800N added is also shown. When the initial pH is from 4 to 11, the adsorbent surface is negatively charged, and the increased negative charge repulsion will reduce the adsorption effect. 3- and HPO4 2- Compared to H2PO 4- , the adsorption free energy is higher, which is not conducive to the adsorption of phosphorus. Under acidic conditions, the lanthanum ions of La-800N precipitate and react with phosphate ions to produce chemical precipitation to form lanthanum phosphate, which is consistent with the XRD characterization analysis, thereby removing phosphorus. When the pH is acidic, the phosphate ions in the solution are mainly in the form of H2PO4 4- and HPO4 2- The La-800N surface is easily deprotonated, and La-800N exchanges ligands with phosphate, thereby quickly removing phosphorus.

[0055] from Figure 3 It can be seen that compared with the phosphate-containing water body with pH=9-10, the adsorption effect of La-800N is better when the pH of the phosphate-containing water body is 4-8, which indicates that La-800N binds dihydrogen phosphate ions better than hydrogen phosphate ions. When the pH is adjusted from 10 to 11, the OH in the water -The amount of La-OH groups on the surface of La-800N increases, which enhances the electrostatic repulsion and competes with phosphate for active sites. In addition, with the increase of pH, the La-OH groups on the surface of La-800N decrease and the La-O groups increase, which also enhances the electrostatic repulsion and leads to a decrease in the adsorption amount. Therefore, in practical applications, the pH of the phosphate-containing water is adjusted to 4-8 before adding the lanthanum-modified phosphorus adsorbent to obtain the best adsorption effect.

[0056] In order to explore the removal of phosphorus in actual water bodies by La-800N, the inhibitory effect of La-800N on phosphorus release from river sediment was studied. A field experiment was conducted, and the sampling time of the field experiment was January 11, 2024. After the sediment in the river was taken out, a large number of large impurities such as leaves, stones, and cigarette butts were removed, put into aluminum foil bags, sealed, and brought into the laboratory, and placed in a 60°C oven to keep a constant weight. After being placed in the oven for 48 hours to dry, it was taken out, ground, and then the resulting product was sieved through a 100-mesh sieve, stored in a drying cabinet, marked and sealed.

[0057] The experimental equipment used four 900mL wide-mouth bottles. 100g of dried river sediment was added to the bottom of the wide-mouth bottle. In order to prevent the sediment from splashing onto the bottle wall, overlying water was added to the wide-mouth bottle by siphon method. Deionized water was used as the overlying water. Water was added to the 900mL mark, and then the wide-mouth bottle was sealed with a bottle cap.

[0058] The first of the four wide-mouth bottles was marked as A, and La-800N was added to the bottle to explore the inhibitory effect of La-800N on the release of phosphorus from riverbed sediments. The second wide-mouth bottle was marked as B, and no adsorbent was added to the bottle to explore the release of phosphorus from riverbed sediments. The third and fourth wide-mouth bottles were marked as C and D, respectively. Wide-mouth bottles C and D were treated in the same way as wide-mouth bottles A and B, respectively, as controls. The measurement period was 12 days, with measurements taken once a day for the first 6 days, and the same operation was repeated each time, followed by measurements every 2 days. Observe the changing trends of total phosphorus and phosphate.

[0059] When La-800N is not added, Figure 4-Figure 5 It can be seen that the range of total phosphorus concentration is between 0.08mg / L-0.18mg / L, and the range of phosphate concentration is between 0.07mg / L-0.09mg / L. In general, the change trend of total phosphorus is more obvious, and the change trend of phosphate is relatively stable. The overall change trend of total phosphorus concentration is upward. The total phosphorus concentration on the 12th day is 2.1 times that of the 1st day. Since the sampling time is winter and the temperature is low, the overall phosphorus concentration is low. This is because there is more oxygen in the water in winter. In the low temperature environment, ion exchange is relatively less frequent, so phosphorus release is relatively slow. In general, within these 12 days, the release of total phosphorus increased sharply in the first 6 days, so the test was conducted once a day. From the 6th to the 12th day, the trend of phosphorus release tended to be stable.

[0060] After adding La-800N, after 12 days of experiment on inhibiting phosphorus release from sediment, the total phosphorus concentration ranged from 0.03mg / L to 0.08mg / L, and the phosphate concentration ranged from 0.02mg / L to 0.05mg / L. The total phosphorus dropped from 0.08mg / L to 0.03mg / L, and the phosphate dropped from 0.05mg / L to 0.02mg / L. In the first 5 days, the total phosphorus decreased sharply, and in the next 7 days, the trend of phosphorus inhibition tended to be stable.

[0061] It can be seen that the phosphorus released from the riverbed mud in the dredged water increases with time, and the amount of phosphorus released increases. After adding the prepared adsorbent La-800N, it has a significant inhibitory effect on the release of phosphorus. This shows that La-800N can also be tried to be applied to the adsorption of phosphorus in actual water bodies, which can play a significant role in water resource protection and improvement of water environment.

[0062] In order to avoid the situation that the phosphorus adsorbent is directly put into the actual water body and may be covered by the bottom mud of the water body, thereby affecting the adsorption effect of phosphorus in the water body, and it is not easy to recover for secondary utilization, when the above-mentioned lanthanum-modified phosphorus adsorbent is put, the phosphorus adsorbent is first placed in a containing device and then put into the phosphorus-containing water body, see Figure 6 , Fig. 9 , Fig.10 The containing device includes a pair of rectangular plates 1 connected in a cross shape, and a pair of rectangular grooves 101 are symmetrically provided on the rectangular plates 1 for accommodating lanthanum-modified phosphorus adsorbents. A filter screen 2 is provided on both sides of the rectangular groove 101 for blocking the lanthanum-modified phosphorus adsorbents and performing water exchange. When the containing device is put into the water body that needs to be purified, compared with using an adsorption bag or an adsorption box to accommodate the phosphorus adsorbent, because the containing device is a cross structure, it will not be completely sunk into the bottom mud of the water body, and because it will not be completely buried by the bottom mud, it is convenient to salvage it out of the water body and replace the phosphorus adsorbent. Specifically, the filter screen 2 is connected to the rectangular plate 1 by a snap, which is convenient for removing the filter screen 2 to replace the phosphorus adsorbent.

[0063] When used in some wide water bodies, areas far from land need to be placed by transport ships carrying containers. Due to the overall structure of the containers, the stacked containers occupy a large area. The transport ship cannot carry too many containers at a time and needs to load the containers back and forth, which affects the placement efficiency. Figure 7-Figure 11A first strip groove 102 is upwardly opened at the bottom of one rectangular plate 1 to separate a pair of rectangular grooves 101 thereon, and a second strip groove 103 is downwardly opened at the top of the other rectangular plate 1 to separate a pair of rectangular grooves 101 thereon, which is used to connect the two rectangular plates 1 to form a cross shape, and a receiving groove 104 is opened on both sides of the second strip groove 103. A slider 3 is slidably arranged in the receiving groove 104, and the inward end of the slider 3 is connected to one end of a spring 4, and the other end of the spring 4 is connected to the rectangular plate 1. The outward end of the slider 3 has an inclined surface 301 with the bottom inclined toward the slider 3 on the opposite side. When the spring 4 is in a natural state, the inclined surface 301 is in the receiving groove 104. A limiting groove 105 is provided at the top of the first strip groove 102. When the two rectangular plates 1 are connected to form a cross shape through the first strip groove 102 and the second strip groove 103, the sliders 3 are all in the limiting groove 105. A pair of third strip grooves 106 are opened on one side of a rectangular plate 1 with a receiving groove 104. The pair of third strip grooves 106 are respectively connected with the two receiving grooves 104. A protrusion 302 is provided on the two sliders 3. The two protrusions 302 are respectively in the pair of third strip grooves 106. When the spring 4 is in a natural state, the distance between the end of the third strip groove 106 away from the second strip groove 103 and the protrusion 302 is greater than the length of the slider 3 protruding from the receiving groove 104.

[0064] When transporting the receiving device, first separate the two rectangular plates 1 and then place them overlappingly. When the receiving device needs to be placed, connect the two rectangular plates 1 through the first strip groove 102 and the second strip groove 103. In the process of the upper rectangular plate 1 being gradually inserted into the lower rectangular plate 1 through the first connecting groove, the inclined surface 301 of the slider 3 will contact the upper rectangular plate 1 and be pushed into the receiving groove 104 by the upper rectangular plate 1. When the third strip groove 106 is aligned with the slider 3, the slider 3 will enter the limiting groove 105 under the push of the spring 4, limiting the upper rectangular plate 1 from being separated from the lower rectangular plate 1. In this way, the receiving device can be quickly assembled and the placement efficiency can be improved. When the phosphorus adsorbent needs to be replaced later and the receiving device needs to be transported and transferred again, the two rectangular plates 1 can be separated by pushing the slider 3 completely into the receiving groove 104 through the protrusion 302, and then the rectangular plates 1 can be stacked and transferred.

[0065] The above description is only a preferred embodiment of the present invention, and is not intended to be the only one or to limit the present invention. Those skilled in the art should understand that various changes or equivalent substitutions made to the present invention without departing from the scope of the present invention are within the scope of protection of the present invention.

Claims

1. A lanthanum-modified phosphorus adsorbent, characterized in that: The preparation steps include: S100, collecting sludge from the rainwater pipes, grinding and drying it, filtering it through a sieve, and then storing it in a drying cabinet; S200, pyrolyzing the rainwater pipe ditch sludge treated in step S100 under continuous nitrogen conditions and a temperature of 800° C. to obtain a phosphorus adsorbent; S300, adding the phosphorus adsorbent obtained in step S200 to the LaCl3 solution and stirring until the mixture is uniformly mixed, then adding the NaOH solution dropwise and stirring until the mixture is uniformly mixed, then adjusting the pH of the solution to 8-12 and stirring until the mixture is uniformly mixed, and finally standing for a preset time; S400, after filtration and drying, a lanthanum-modified phosphorus adsorbent is obtained.

2. A lanthanum-modified phosphorus adsorbent according to claim 1, characterized in that: The mass concentration of the LaCl 3 solution in step S300 is 5 g / L-30 g / L, and the mass of the phosphorus adsorbent added to every 100 mL of the LaCl 3 solution is 5 g.

3. A lanthanum-modified phosphorus adsorbent according to claim 2, characterized in that: The mass concentration of the LaCl3 solution in step S300 is 20 g / L.

4. A lanthanum-modified phosphorus adsorbent according to claim 3, characterized in that: The concentration of the NaOH solution added in step S300 is 2 mol / L, and the amount of the NaOH solution added is 3 ml per 100 mL of LaCl 3 solution. When adjusting the pH of the solution, the pH of the solution is adjusted to 10.

5. The lanthanum-modified phosphorus adsorbent according to claim 1, characterized in that: In step S300, the phosphorus adsorbent obtained in step S200 is added to the LaCl3 solution and stirred for 2 hours, then the NaOH solution is added dropwise and stirred for 16 hours, the pH of the solution is adjusted to 8-12 and stirred for 6 hours, and finally allowed to stand for 24 hours.

6. Application of a lanthanum-modified phosphorus adsorbent, characterized in that: A lanthanum-modified phosphorus adsorbent as described in any one of claims 1 to 5 is added to a phosphorus-containing water body.

7. The use of a lanthanum-modified phosphorus adsorbent according to claim 6, characterized in that: The lanthanum-modified phosphorus adsorbent is placed in a containing device and then put into a phosphorus-containing water body. The containing device comprises a pair of rectangular plates (1) connected in a cross shape. A pair of rectangular grooves (101) are symmetrically provided on the rectangular plates (1) for containing the lanthanum-modified phosphorus adsorbent. A filter (2) is provided on both sides of the rectangular groove (101) for blocking the lanthanum-modified phosphorus adsorbent and for water exchange.

8. The use of a lanthanum-modified phosphorus adsorbent according to claim 7, characterized in that: A first strip groove (102) is formed upwardly at the bottom of one rectangular plate (1) to separate a pair of rectangular grooves (101) thereon, and a second strip groove (103) is formed downwardly at the top of the other rectangular plate (1) to separate a pair of rectangular grooves (101) thereon, and is used to connect the two rectangular plates (1) to form a cross shape. A receiving groove (104) is formed on both sides of the second strip groove (103). A slider (3) is slidably disposed in the receiving groove (104). The inward end of the slider (3) is connected to one end of a spring (4), and the other end of the spring (4) is connected to the rectangular plate (1). The outward end of the slider (3) has an inclined surface (301) with the bottom inclined toward the slider (3) on the opposite side. When the spring (4) is in a natural state, the inclined surface (301) is in the receiving groove (104). A limiting groove (105) is provided at the top of the first strip groove (102). When the two rectangular plates (1) are connected to form a cross shape through the first strip groove (102) and the second strip groove (103), the sliders (3) are all located in the limiting groove (105). A pair of third strip grooves (106) is provided on one side of a rectangular plate (1) having a receiving groove (104). The pair of third strip grooves (106) are respectively connected to the two receiving grooves (104). The two sliders (3) are provided with protrusions (302). The two protrusions (302) are respectively located in the pair of third strip grooves (106). When the spring (4) is in a natural state, the distance between the end of the third strip groove (106) away from the second strip groove (103) and the protrusion (302) is greater than the length of the slider (3) protruding from the receiving groove (104).

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