Preparation method of lanthanum-zirconium bimetallic adsorbent and method for enriching phosphorus in water body

Abstract

The application discloses a preparation method of a lanthanum-zirconium bimetallic adsorption material, and has the characteristics that the steps are as follows: the D201 resin is cleaned with deionized water for three times, and then the resin is soaked in 1 mol / L HCl solution with a volume twice that of the resin for 6 hours; the soaked resin is cleaned with deionized water until the pH value is 4; then the resin is soaked in 1 mol / L NaOH solution with a volume twice that of the resin for 6 hours; the re-soaked resin is cleaned with deionized water until the pH value is 8; drying treatment is carried out at 333 K; a certain amount of D201 resin is respectively placed in 100 ml of 0.5 mol / L lanthanum chloride solution and 25 ml of 0.5 mol / L zirconium chloride solution, and the shaking table is shaken for 24 hours; the resin is filtered and dried; the resin is placed in 100 ml of 0.5 mol / L sodium carbonate solution, and the shaking table is shaken and filtered and dried to obtain a product C-DLZ-4:1 resin. The preparation process of the phosphorus adsorbent is simple, the phosphorus absorption rate is as high as 99.94%, the adsorption capacity is as high as 35.8 mg / g, the phosphorus adsorbent has good reusability, and the cost of dephosphorization in wastewater treatment is reduced.

Description

Technical Field

[0001] This invention relates to the field of phosphorus adsorbents for water treatment, and particularly to a method for preparing lanthanum and zirconium bimetallic adsorbent materials and a method for enriching phosphorus in water. Background Technology

[0002] Phosphorus is an essential nutrient element for life and the maintenance of ecosystems, but it is also a major cause of eutrophication. Eutrophication leads to the proliferation of algae, causing a sharp drop in dissolved oxygen in the water. Simultaneously, algae produce large amounts of cyanobacterial toxins, resulting in the death of aquatic organisms, reduced biodiversity, further deterioration of water quality, and ultimately, the collapse of aquatic ecosystems. Furthermore, my country faces a phosphorus resource shortage crisis. Therefore, realizing the recovery and reuse of phosphorus resources in water bodies is an effective means to alleviate the pressure of eutrophication and is of great significance to sustainable economic and social development.

[0003] Currently, methods for phosphorus treatment and recovery include chemical precipitation, biological methods, membrane separation, ion exchange, and adsorption. Among these, adsorption is widely used for phosphorus removal and recovery from water bodies due to its advantages such as stable removal efficiency, wide applicability, and no secondary pollution. Currently researched and applied phosphorus adsorbents mainly include natural adsorbents, industrial waste, and synthetic adsorbents. Natural materials and industrial waste adsorbents are relatively inexpensive, but their phosphorus adsorption capacity is relatively poor, and some industrial wastes, such as slag, may also have potential ecotoxicity. Therefore, improving the adsorption capacity and reusability of existing adsorbents is a key focus of current adsorption research.

[0004] Lanthanum and zirconium are highly effective at phosphorus removal due to their high affinity for phosphorus, and have therefore received increasing attention in recent years. Zirconium-modified adsorbents exhibit strong acid resistance, preventing metal leaching under acidic conditions during adsorption / desorption, and demonstrate excellent stability and reusability. Compared to zirconium-modified adsorbents, lanthanum-based adsorbents possess superior phosphorus capture capabilities, but due to irreversible combination, their desorption efficiency and reusability are not as good as zirconium-based adsorbents.

[0005] Chinese patent disclosure for "A phosphorus removal adsorbent loaded with lanthanum and zirconium from rapeseed straw and its preparation method" (CN2017105864136): Rapeseed straw powder is added to a 1-3% MgCl2 solution at a material-to-liquid ratio of 1:1.5-3. The mixture is then activated in a microwave oven, filtered, and dried to obtain wet rapeseed straw residue. Two solids, La(NO3)3·6H2O and ZrOCl2·8H2O, are added to a 0.2-0.5% sodium dodecyl sulfate solution to adjust the pH to 7-9, thus preparing a lanthanum-zirconium ion precursor solution. The wet rapeseed straw residue is then added to the lanthanum-zirconium ion precursor solution, stirred, filtered, and the filter residue is dried at 50-80℃ to obtain the adsorbent. However, this adsorbent has a phosphorus adsorption rate of only 96.7% and a saturated adsorption capacity of only 24.6 mg / g. Furthermore, this adsorbent is not reusable, leading to high wastewater treatment costs. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a lanthanum-zirconium bimetallic adsorbent material with high phosphorus adsorption rate and good reusability.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a lanthanum-zirconium bimetallic adsorbent, comprising lanthanum and zirconium supported on D201 resin.

[0009] The steps are as follows:

[0010] a. Pour the newly purchased D201 resin into a beaker and rinse it three times with deionized water to remove insoluble particulate impurities from its surface; b. Soak it in a 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours, stirring appropriately during soaking; c. Rinse the soaked resin with deionized water until its pH reaches 4, then soak it in a 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours, stirring appropriately during soaking; d. The resin, after being soaked again, was washed with deionized water until its pH reached 8; e. The washed resin was placed in an electric thermostatic drying oven and dried at 333K; f. A certain amount of D201 resin was placed in 100ml of a 0.5mol / L solution of lanthanum chloride and zirconium chloride, shaken on a shaker for 24h, filtered, and dried; g. The D201 resin treated as above was placed in 100ml of a 0.5mol / L sodium carbonate solution, shaken on a shaker for 24h, filtered, and dried to finally obtain the lanthanum and zirconium-loaded D201 resin.

[0011] Another object of the present invention is to provide a method for enriching phosphorus in water using the above-mentioned adsorbent.

[0012] Another object of the present invention is achieved as follows:

[0013] The method for enriching phosphorus in water comprises the following steps:

[0014] a) Load lanthanum and zirconium-loaded D201 resin into an adsorption column; b) Connect the bottom and top outlets to flexible tubes, and place the inlet in the water; c) Turn on the water pump, allowing water to flow from bottom to top through the adsorption column, where the D201 resin adsorbs phosphorus; d) After a period of operation, turn off the water pump and remove the D201 resin from the adsorption column; e) Include the following steps: Weigh 4g of D201 resin and load it into the adsorption column. The column has a perforated plate at both the bottom and top, covered with a layer of quartz sand; connect the bottom and top outlets to flexible tubes, and place the inlet in the water; turn on the water pump, allowing water containing 5mg / L of phosphorus to flow from bottom to top through the adsorption column, where the D201 resin adsorbs phosphorus; after a period of operation, turn off the water pump and remove the D201 resin from the adsorption column. Place the removed material in a conical flask containing 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0015] Compared with the prior art, the present invention has the following features and advantages:

[0016] 1. This invention loads lanthanum and zirconium onto D201 resin to obtain a novel lanthanum-zirconium bimetallic adsorbent. This not only inherits the advantages of functional metal components and enhances adsorption capacity, but also makes up for the defects of single metals. At the same time, it can further improve adsorption capacity and solve the problem of traditional adsorbents lacking active sites.

[0017] 2. The phosphorus removal adsorbent material proposed in this invention has a simple preparation process and exhibits excellent phosphorus adsorption effect, overcoming the technical problems of complex preparation processes and insufficient adsorption capacity of the obtained adsorbent materials in existing technologies. The phosphorus absorption rate is as high as 99.94%, and the adsorption capacity is as high as 34.97 mg / g.

[0018] 3. The desorption method of the phosphorus adsorbent of the present invention is simple and the desorption effect is good. Therefore, the phosphorus adsorbent of the present invention has better reusability, which is beneficial to reducing the dephosphorization cost in the wastewater treatment process. Attached Figure Description

[0019] Figure 1 This is an experimental apparatus for removing phosphorus from water using the phosphorus adsorbent of the present invention.

[0020] Figure 2 This is the method used in Embodiment 1 of the present invention. Figure 1 The diagram shows the phosphorus removal efficiency of the device after repeated use of the phosphorus adsorbent of the present invention seven times.

[0021] Figure 3 This is the method used in Embodiment 1 of the present invention. Figure 1The diagram shows the phosphorus desorption efficiency of the device after repeated use of the phosphorus adsorbent of the present invention seven times. Detailed Implementation

[0022] The operation steps of the present invention will be described in a complete and clear manner with reference to the apparatus diagram of the present invention and examples.

[0023] Figure 1 1-Inlet, 2-Water pump, 3-Adsorption column, 4-Lanium-zirconium supported D201 material, 5-Quartzite sand layer, 6-Outlet.

[0024] Figure 1 In the adsorption column, there is a perforated plate at the bottom, which is covered with quartz sand, and another perforated plate at the top, which may or may not be covered with quartz sand. The resin is located between the upper and lower perforated plates.

[0025] Example 1:

[0026] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in a 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in a 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; d) a) Wash the re-soaked resin with deionized water until its pH = 8; b) Place the washed resin in an electric thermostatic drying oven and dry it at 333K; c) Take 5g of D201 resin and place it in 100ml of 0.5mol / L lanthanum chloride and 25ml of 0.5mol / L zirconium chloride solution, shake on a shaker for 24h, filter, and dry; g) Place the D201 resin treated above in 100ml of 0.5mol / L sodium carbonate solution, shake on a shaker for 24h, filter, and dry to finally obtain C-DLZ-4:1 resin.

[0027] Method for enriching phosphorus in water: a) Weigh 4g of C-DLZ-4:1 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the C-DLZ-4:1 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0028] Comparative Example 1:

[0029] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; d) Wash the soaked resin with deionized water until its pH = 8; e) Place the washed resin in an electric thermostatic drying oven and dry it at 333 K to obtain D201 resin.

[0030] Method for enriching phosphorus in water: a) Weigh 4g of D201 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus in the water is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0031] Example 2:

[0032] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; d) Wash the soaked resin with deionized water until its pH = 8; e) Place the washed resin in an electric thermostatic drying oven and dry it at 333 K; f) Take 5g... D201 resin was placed in 100 ml of 0.5 mol / L lanthanum chloride solution and 25 ml of 0.5 mol / L zirconium chloride solution, shaken on a shaker for 24 h, filtered, and dried; g. The D201 resin treated above was placed in 100 ml of 0.5 mol / L sodium carbonate solution, shaken on a shaker for 24 h, filtered, and dried to finally obtain C-DLZ-4:1 resin.

[0033] Method for enriching phosphorus in water: a) Weigh 2g of C-DLZ-4:1 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus in the water is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0034] Comparative Example 2:

[0035] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; d) Wash the soaked resin with deionized water until its pH = 8; e) Place the washed resin in an electric thermostatic drying oven and dry it at 333 K to obtain D201 resin.

[0036] Method for enriching phosphorus in water: a) Weigh 2g of D201 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus in the water is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0037] Example 3:

[0038] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in a 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in a 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; d) a) Wash the re-soaked resin with deionized water until its pH = 8; b) Place the washed resin in an electric thermostatic drying oven and dry it at 333K; c) Take 5g of D201 resin and place it in 100ml of 0.5mol / L lanthanum chloride and 25ml of 0.5mol / L zirconium chloride solution, shake on a shaker for 24h, filter, and dry; g) Place the D201 resin treated above in 100ml of 0.5mol / L sodium carbonate solution, shake on a shaker for 24h, filter, and dry to finally obtain C-DLZ-4:1 resin.

[0039] Method for enriching phosphorus in water: a) Weigh 1g of C-DLZ-4:1 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus in the water is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0040] Comparative Example 3:

[0041] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring; d) Wash the soaked resin with deionized water until its pH = 8; e) Place the washed resin in an electric thermostatic drying oven and dry it at 333 K to obtain D201 resin.

[0042] Method for enriching phosphorus in water: a) Weigh 1g of D201 resin and load it into an adsorption column; b) Connect the bottom and top outlets to flexible tubing and place the inlet in the water; c) Turn on the water pump, allowing water containing 5mg / L of phosphorus to flow from bottom to top through the adsorption column, where the D201 resin adsorbs the phosphorus; d) After a period of operation, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in a conical flask containing 100mL of 0.5mol / L sodium hydroxide solution, place it in a shaker at 25℃ and 160rpm, shake for 30min, then remove it and measure the phosphorus concentration in the supernatant. Repeat this process multiple times. The subsequent desorption method is the same as above.

[0043] Comparative Example 4:

[0044] Preparation of a phosphorus removal adsorption material: a) Pour newly purchased D201 resin into a beaker and wash it three times with deionized water to remove insoluble particulate impurities from its surface; b) Soak it in a 1 mol / L HCl solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; c) Wash the soaked resin with deionized water until its pH = 4, then soak it in a 1 mol / L NaOH solution (twice the resin volume, 2 BV) for 6 hours with appropriate stirring during soaking; d) a) Wash the re-soaked resin with deionized water until its pH = 8; b) Place the washed resin in an electric thermostatic drying oven and dry it at 333K; c) Take 5g of D201 resin and place it in 100ml of 0.5mol / L lanthanum chloride and 25ml of 0.5mol / L zirconium chloride solution, shake on a shaker for 24h, filter, and dry; g) Place the D201 resin treated above in 100ml of 0.5mol / L sodium hydroxide solution, shake on a shaker for 24h, filter, and dry to finally obtain H-DLZ-4:1 resin.

[0045] Method for enriching phosphorus in water: a) Weigh 4g of H-DLZ-4:1 resin and load it into an adsorption column; b) Connect the bottom and top outlets to hoses and place the inlet in the water; c) Turn on the water pump and allow water containing 5mg / L of phosphorus to pass through the adsorption column from bottom to top, where the phosphorus in the water is adsorbed by the D201 resin; d) After running for a period of time, turn off the water pump and remove the D201 resin from the adsorption column; e) Place the removed material in 100mL of 0.5mol / L sodium hydroxide solution for desorption treatment, repeating this process multiple times.

[0046] Dynamic adsorption experiments were conducted at room temperature, and the phosphorus concentration at the outlet was measured. The results are shown in the graph. The graph shows that the phosphorus adsorption performance of the lanthanum-zirconium bimetallic modified D201 resin differs significantly from that of the unmodified D201 resin and the D201 resin modified with sodium hydroxide. The phosphorus removal rate of the adsorbent of this invention is as high as 99.94%, while the phosphorus removal rate of Comparative Example 1 is only 78.6%, and that of Comparative Example 4 is only 83.5%. The lanthanum-zirconium bimetallic adsorbent prepared in this invention has excellent phosphorus adsorption performance.

[0047] Table 1 (Example 1: Data on the number of times the device was reused)

[0048]

[0049] Table 2: (Desorption data from Example 1)

[0050] Number of times of reuse Adsorption capacity (mg / g) Desorption capacity (mg / g) Desorption rate 0 34.97 31.30 89.50％ 1 33.35 29.60 88.75％ 2 31.34 28.18 89.92％ 3 30.98 27.26 87.98％ 4 30.80 25.05 81.33％ 5 30.98 25.22 81.40％ 6 27.70 21.35 77.06％

Claims

1. A method for enriching phosphorus in water using a lanthanum-zirconium bimetallic adsorbent, characterized in that, The preparation of the lanthanum-zirconium bimetallic adsorbent includes the following steps: a. Pour the newly purchased D201 resin into a beaker and rinse it three times with deionized water to remove insoluble particulate impurities from its surface. b. Soak the resin in a 1 mol / L HCl solution, twice the volume of the resin, for 6 hours, with appropriate stirring during the soaking process. c. Wash the soaked resin with deionized water until its pH=4, then soak it in 1mol / L NaOH solution twice the volume of the resin for 6 hours, with appropriate stirring during soaking. d. Rinse the resin after soaking again with deionized water until its pH = 8; e. Place the cleaned resin in an electric constant temperature drying oven and dry it at 333K. f. Take 5g of D201 resin and place it in 100ml of 0.5mol / L lanthanum chloride and 25ml of 0.5mol / L zirconium chloride solution. Shake on a shaker for 24h, filter, and dry. g. The D201 resin treated above was placed in 100 ml of 0.5 mol / L sodium carbonate solution, shaken on a shaker for 24 h, filtered, dried, and finally the product C-DLZ-4:1 resin was obtained. The process of enriching phosphorus in water includes the following steps: (1) Weigh 4g of C-DLZ-4:1 resin and load it into the adsorption column. There is a well plate at the bottom and top of the adsorption column, and the well plate is covered with a layer of quartz sand. (2) The bottom and top outlets are connected to hoses, and the inlet is placed in the water; (3) Turn on the water pump switch and let the water containing 5 mg / L of phosphorus pass through the adsorption column from bottom to top and be adsorbed by the C-DLZ-4:1 resin; (4) After running for a period of time, turn off the water pump and remove the C-DLZ-4:1 resin from the adsorption column; (5) Place the extracted material in an Erlenmeyer flask containing 100 mL of 0.5 mol / L sodium hydroxide solution for desorption treatment, repeating the process multiple times.

2. The method for enriching phosphorus in water using a lanthanum and zirconium bimetallic adsorbent according to claim 1, characterized in that, The C-DLZ-4:1 resin was used to enrich phosphorus in water seven times. After each enrichment, the extracted material was placed in an Erlenmeyer flask containing 100 mL of 0.5 mol / L sodium hydroxide solution and placed in a shaker at 25°C and 160 rpm for 30 min. The phosphorus concentration in the supernatant was then measured. The phosphorus removal rates of the resin from the first to the seventh enrichment were calculated to be 99.94%, 95.3%, 89%, 88%, 87%, 88%, and 78%, respectively, with corresponding adsorption capacities of 34.97 mg / g, 33.35 mg / g, 31.34 mg / g, 30.98 mg / g, 30.80 mg / g, 30.98 mg / g, and 27.70 mg / g.

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