Adsorption material of organic phosphonic acid group modified metal oxide and hardness removal application of adsorption material

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to an adsorption material of an organic phosphonic acid group modified metal oxide and hardness removal application thereof.The adsorption material takes a metal oxide as a carrier, and surface functionalization modification is conducted on the metal oxide through organic phosphonate containing a plurality of organic phosphonic acid functional groups; wherein part of the organic phosphonic acid functional groups are combined with the surface of the metal oxide, and the rest of the organic phosphonic acid functional groups are modified on the surface of the metal oxide; the adsorption material serves as a water treatment agent under the water treatment condition that the pH value is 8 or above, and organic phosphonate functional groups for surface modification are combined with hardness ions in water through complexation, so that deep hardness removal is achieved. The adsorption material prepared by the method can deeply remove trace calcium and magnesium hardness ions in a water body through specific complexation under a mild condition close to neutral, and the pH value does not need to be greatly adjusted, so that the addition of agents such as acid and alkali is remarkably reduced.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to an adsorbent material based on organophosphonic acid groups modified metal oxides for deep removal of calcium and magnesium, its preparation method, and its hardening removal application. Background Technology

[0002] Against the backdrop of the global trend towards intelligent and precise high-end manufacturing, the demand for ultrapure water in strategic emerging fields such as semiconductor chip manufacturing, biopharmaceuticals, and seawater desalination is experiencing explosive growth. Even trace amounts of hardness ions such as calcium and magnesium in the process water of these critical industries can form nanoscale scale on the surfaces of precision equipment, leading to increased chip defect rates, decreased drug activity, and degraded reverse osmosis membrane performance, severely impacting product quality and equipment lifespan. Therefore, developing novel water treatment softening materials with ultra-strong hardness ion removal capabilities has become an urgent need to support the development and technological innovation of my country's high-end manufacturing industry.

[0003] Currently, the most common methods for treating low-hardness water are ion exchange and chemical precipitation. Ion exchange, while achieving good hardness removal, suffers from resin material aging during the process, requiring frequent regeneration with acid and alkali chemicals. This is not only complex and costly but also generates large amounts of saline wastewater. Furthermore, resin particles may break down over time, leading to increased organic matter content and particulate matter in the effluent. Conventional chemical precipitation methods, such as double-alkali titration, require raising the water's pH to above 10 to achieve ideal hardness removal. This not only consumes large amounts of alkali but also introduces additional sodium and carbonate ions, increasing the total salt content. This water quality change burdens subsequent purification units, affecting the overall system's stable operation and water purity.

[0004] Therefore, it is necessary to develop a new adsorption material and technology that can effectively remove trace hardness components under near-neutral and mild conditions, while avoiding the introduction of new impurities into the water. This would better meet the stringent requirements of modern high-end industries for ultrapure water quality, while reducing operating costs and environmental impact. Summary of the Invention

[0005] The purpose of this invention is to provide an adsorbent material based on organophosphonic acid groups modified metal oxides for deep removal of calcium and magnesium, its preparation method, and its application in hardness removal. The prepared adsorbent material can deeply remove trace amounts of calcium and magnesium hardness ions from water under near-neutral and mild conditions through specific complexation, without requiring significant pH adjustment, thus significantly saving on the dosage of acids and alkalis. Furthermore, this material can be used as filter media to fill adsorption columns, and after adsorption saturation, it can be efficiently regenerated through mild acid washing, achieving recycling.

[0006] The specific technical solution adopted by this invention is as follows: In a first aspect, this application provides an adsorbent material, wherein the adsorbent material uses a metal oxide as a carrier, and the metal oxide is surface-modified by an organophosphonate containing multiple organophosphonic acid functional groups; In this embodiment, some of the organophosphonic acid functional groups are bonded to the surface of the metal oxide, and the remaining portion of the organophosphonic acid functional groups are modified on the surface of the metal oxide.

[0007] In a second aspect of this application, the adsorbent material is used as a water treatment agent under water treatment conditions with a pH of 8 or higher. The organophosphonate functional groups used for surface modification bind to hardness ions in the water through complexation, thereby achieving deep hardness removal.

[0008] A third aspect of this application provides a preparation method, comprising the following steps: Step 1: Disperse the metal oxide in deionized water to form a suspension; Step 2: Add organophosphonates to the suspension and stir to mix, obtaining a mixture; Step 3: Measure a fixed amount of alkaline solution to adjust the pH of the mixture to 7.5-12, and then proceed with the hydrothermal reaction. Step 4: After the hydrothermal reaction is completed, the reaction products are subjected to solid-liquid separation, washing, drying and grinding to obtain the adsorbent material.

[0009] As an alternative, the metal oxide includes one or more of bismuth oxide, aluminum oxide, iron oxide, and ferrous oxide.

[0010] As an optional approach, in step one, the dosage of the metal oxide is 1 g / L to 10 g / L, based on the volume of deionized water.

[0011] As an optional option, the organophosphonate in step two includes one or more of aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylphosphonic acid, and ethylenediaminetetraacetic acid; The concentration of the organophosphonate, calculated as phosphorus, is 0.01M to 0.1M.

[0012] As an optional approach, the temperature of the hydrothermal reaction in step three is 100℃~150℃, and the reaction time is 1h~8h.

[0013] A fourth aspect of this application provides an application of an adsorbent material, including... Column packing: The adsorbent material is packed into an adsorption column; Hardness removal and effluent: The raw water to be treated is passed through the adsorption column for a certain empty bed contact time to perform deep hardness removal treatment and obtain purified effluent.

[0014] As an optional solution, it also includes, Regeneration of the adsorption column: When the concentration of hardness ions in the outlet water of the adsorption column reaches the set threshold, stop the water intake; use a dilute acid solution with pH=6-6.5 as the eluent, pass it through the adsorption column in either the reverse or forward direction to elute the complexed hardness ions, and then rinse with ultrapure water until the pH of the outlet water is neutral to complete the regeneration and restore the hardness removal performance.

[0015] The technical effects achieved by this invention are as follows: The adsorbent material prepared by this invention can remove trace amounts of calcium and magnesium hardness ions in water through specific complexation under near-neutral and mild conditions without significantly adjusting the pH value, thereby significantly saving the dosage of acid, alkali and other reagents.

[0016] The adsorbent material prepared by this invention can be used as a filter medium to fill glass adsorption columns. After adsorption saturation, it can be efficiently regenerated by gentle acid washing, thus achieving recycling. Attached Figure Description

[0017] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2(a) is a scanning electron microscope image of the adsorbent material obtained by the preparation method in Example 1 of the present invention at the first magnification. Figure 2(b) is a scanning electron microscope image of the adsorbent material obtained by the preparation method in Example 1 of the present invention at the second magnification. Figure 3 This is the infrared spectrum of the adsorbent material obtained by the preparation method in Example 1 of the present invention; Figure 4 These are the dual-alkali hardening effect diagrams of the adsorbent materials prepared in Examples 1 to 3 under pH=8 conditions of this invention; Figure 5 This is a diagram showing the adsorption and regeneration effect of the adsorbent material in Embodiment 4 of the present invention; Figure 6 This is a flowchart of the adsorption regeneration experiment in Embodiment 4 of the present invention. Detailed Implementation

[0018] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0019] Example 1: A method for preparing an adsorbent material of an organophosphonic acid group-modified metal oxide, such as... Figure 1 As shown, the preparation method includes the following steps: Step S1, Carrier Dispersion: Weigh 1.5 g / L bismuth oxide as a quantitative metal oxide, disperse it in 100 mL of deionized water to form a uniform suspension, and stir with a magnetic stirrer at a speed greater than 350 rpm for a time of not less than 1 hour to facilitate uniform distribution of the metal oxide powder. The metal oxide powder used in this technical solution can be purchased directly from upstream manufacturers in the industry chain and can be used directly without pre-processing. Refinement: If the oxide powder particles are large or the suspension after stirring is not uniform, such as the occurrence of fine agglomeration in the suspension, an ultrasonic cleaner or ultrasonic homogenizer can be used for ultrasonic treatment. Place the glass stirring cup after stirring into the ultrasonic tank, set the operating power to 50W~100W, and the running time to 20min~60min. Step S2, Organic Modification: Add an organophosphonate solution to the above suspension. In this embodiment, the organophosphonate solution can be 0.1M aminotrimethylphosphonic acid (ATMP). During the addition process, use a magnetic stirrer to mix thoroughly. Among them, the adsorbent material uses metal oxide as a carrier and is surface functionalized by using organophosphonates containing one or more organophosphonic acid functional groups. For example, one organophosphonic acid functional group is stably bonded to the surface of the metal oxide through a POM covalent bond, while the remaining organophosphonic acid functional group is free on the surface of the metal oxide and can bind to hardness ions (calcium and magnesium ions) in the water to achieve water softening and hardness removal. Step S3, hydrothermal synthesis: The pH of the mixture obtained in step S2 was adjusted to 9 using a sufficient amount of 2 mol / L sodium hydroxide solution. The mixture was then transferred to a high-pressure reactor and reacted at 125°C for 4 hours. Step S4: Product Extraction: After the reaction is complete, the product is naturally cooled, centrifuged, repeatedly washed with deionized water, dried at 55°C, and ground to obtain the organophosphonate-modified metal oxide adsorbent material. For example, Figure 2 shows the state of the adsorbent material under a scanning electron microscope. Figure 3 The state of the adsorbent material under infrared spectroscopy is shown in the image. The product, after being centrifuged and repeatedly washed with deionized water, was placed in a drying oven and dried at 55°C.

[0020] It should be noted that Figure 2(a) shows the microstructure of the adsorbent material under a scanning electron microscope at the first magnification, and Figure 2(b) shows the microstructure of the adsorbent material under a scanning electron microscope at the second magnification. These figures visually demonstrate that the adsorbent material exhibits an irregular granular structure with a rough surface, and the particles accumulate to form certain pores. This morphological characteristic indicates that the bismuth oxide support modified with organophosphonates maintains a good particle morphology.

[0021] Example 2: like Figure 1 As shown, a method for preparing an adsorbent material of metal oxide modified with organophosphonic acid groups specifically includes the following steps: Step M1, Carrier Dispersion: Weigh 1.5 g / L of iron oxide as a quantitative metal oxide, disperse it in 100 mL of deionized water to form a uniform suspension. While adding the metal oxide powder, stir with a magnetic stirrer at a speed greater than 350 rpm for a time of not less than 1 hour to facilitate uniform distribution of the metal oxide powder. Refinement: If the oxide powder particles are large or the suspension after stirring is not uniform, such as the occurrence of fine agglomeration in the suspension, an ultrasonic cleaner or ultrasonic homogenizer can be used for ultrasonic treatment. Place the glass stirring cup after stirring into the ultrasonic tank, set the operating power to 50W~100W, and the running time to 20min~60min. Stirring: After ultrasonic treatment, let stand for 20 to 30 minutes, then continue to add deionized water to the glass stirring cup until the total volume of the suspension reaches 100 mL, and stir again with a magnetic stirrer for at least 30 minutes. Step M2, Organic Modification: Add an organophosphonate solution to the above suspension. In this embodiment, the organophosphonate solution can be 0.1M aminotrimethylphosphonic acid (ATMP). During the addition process, use a magnetic stirrer to mix thoroughly. Step M3, hydrothermal synthesis: The pH of the mixture obtained in step M2 was adjusted to 10 using 2 mol / L sodium hydroxide solution, and then the mixture was transferred to a high-pressure reactor and reacted at 125°C for 4 h. Step M4, Product Extraction: After the reaction is complete, the product is cooled naturally, centrifuged, repeatedly washed with deionized water, dried at 55°C and ground to obtain the organophosphonate modified metal oxide adsorbent material. The product, after being centrifuged and repeatedly washed with deionized water, was placed in a drying oven and dried at 55°C.

[0022] Example 3: like Figure 1 As shown, a method for preparing an adsorbent material based on organophosphonic acid functionalized metal oxides specifically includes the following steps: Step N1, Carrier Dispersion: Weigh 1 g / L bismuth oxide as a quantitative metal oxide and disperse it in 100 mL of deionized water to form a uniform suspension. While adding the metal oxide powder, stir with a magnetic stirrer at a speed greater than 350 rpm for a time of not less than 1 hour to facilitate uniform distribution of the metal oxide powder. Refinement: If the oxide powder particles are large or the suspension after stirring is not uniform, such as the occurrence of fine agglomeration in the suspension, an ultrasonic cleaner or ultrasonic homogenizer can be used for ultrasonic treatment. Place the glass stirring cup after stirring into the ultrasonic tank, set the operating power to 50W~100W, and the running time to 20min~60min. Stirring: After ultrasonic treatment, let stand for 20 to 30 minutes, then continue to add deionized water to the glass stirring cup until the total volume of the suspension reaches 100 mL, and stir again with a magnetic stirrer for at least 30 minutes. Step N2, Organic Modification: Add an organophosphonate solution to the above suspension. In this embodiment, the organophosphonate solution can be 0.1M ethylenediaminetetramethylenephosphonic acid (EDTMP). During the addition process, use a magnetic stirrer to mix thoroughly. Step N3, hydrothermal synthesis: The pH of the mixture obtained in step N2 was adjusted to 10 using 2 mol / L sodium hydroxide solution, and then the mixture was transferred to a high-pressure reactor and reacted at 125°C for 4 h. Step N4, Product Extraction: After the reaction is complete, the product is cooled naturally, centrifuged, repeatedly washed with deionized water, dried at 55°C and ground to obtain the organophosphonate modified metal oxide adsorbent material. The product, after being centrifuged and repeatedly washed with deionized water, was placed in a drying oven and dried at 55°C.

[0023] In summary, the adsorbent material obtained by the above preparation method exhibits an irregular granular structure, which allows the metal oxide support to maintain a good particle morphology after modification with organophosphonates, and has the following effects: (1) Increased specific surface area: The rough surface and interparticle pores of the adsorbent material help to increase its specific surface area, thereby increasing the contact between the particle and hardness ions in the water; (2) Increased surface active sites: Organophosphonic acid groups are evenly distributed on the surface of metal oxide support, forming a large number of complexation sites, which significantly enhances the adsorption capacity of adsorbent materials for calcium and magnesium ions, and can be used for deep hardening removal; (3) Practicality: The adsorbent material with granular structure is easy to pack into columns and has a certain degree of fluidity and hydraulic conductivity, making it suitable for continuous flow operation.

[0024] Example 4: This application also provides an application of the adsorbent material, including, Column packing: The adsorbent material is packed into an adsorption column; Hardness removal and effluent: The raw water to be treated is passed through the adsorption column for a certain empty bed contact time to perform deep hardness removal treatment and obtain purified effluent.

[0025] As an optional solution, it also includes, Regeneration of the adsorption column: When the concentration of hardness ions in the outlet water of the adsorption column reaches the set threshold, stop the water intake; use a dilute acid solution with pH=6-6.5 as the eluent, pass it through the adsorption column in either the reverse or forward direction to elute the complexed hardness ions, and then rinse with ultrapure water until the pH of the outlet water is neutral to complete the regeneration and restore the hardness removal performance.

[0026] Since Examples 1 to 3 involve three different pathways, the adsorption material preparation methods can yield three products, which are preferred products. This example conducts laboratory-scale testing of the three products to verify the effectiveness of the adsorption material provided in this application and its application.

[0027] See Figure 4 The water quality conditions for low-hardness water preparation in the laboratory are: pH=7, [Ca...] 2+ ] = 50 mg / L, [Mg 2+ =20mg / L.

[0028] The adsorbent materials prepared in Examples 1 to 3 were used as water treatment agents to treat laboratory water according to the application test method. The pH of the mixed solution was adjusted using 0.2 mol / L sodium hydroxide solution, and hardness ions in the mixed solution were precipitated using a dual-alkali method. In this experimental example, 0.2 mol / L sodium hydroxide solution and 0.5 mol / L sodium carbonate solution were selected as the dual alkalis. After sampling, the Ca2+ in the water was determined by ICP-OES. 2+ and Mg 2+ Ion concentration.

[0029] Experimental results are as follows Figure 4 As shown, under the same conditions of pH=8, the adsorbent materials prepared in Examples 1 to 3, used as water treatment agents, utilize surface-modified organophosphonate functional groups to bind with hardness ions in water through complexation, thereby achieving deep hardness removal and reducing the total concentration of hardness ions (Ca²⁺) to [amount missing]. + With Mg² + The concentration of hardness ions was reduced to below 10 mg / L, achieving highly efficient removal; while the dual-alkali method was essentially ineffective at this concentration of hardness ions under pH=8 conditions, resulting in low removal. These results fully demonstrate the significant advantages of the adsorption material of this invention in water treatment under near-neutral conditions compared to traditional water treatment methods.

[0030] like Figures 4-6 As shown, this application provides an application testing method, which includes the following steps: Preparation stage: Take 40.0 g of the organophosphonate-modified bismuth oxide adsorbent material prepared in Example 1 and pack it into a glass adsorption column with an inner diameter of 2.5 cm by wet method, with a packing volume of about 100 mL; Adsorption stage: Prepare low-hardness water (pH=7, [Ca2+]2000) 2+ The calcium ion concentration at the outlet was continuously monitored by passing the water with a concentration of 50 mg / L (50 mg / L) through a glass adsorption column at a constant flow rate of 1.5 L / h at room temperature. Regeneration stage: The breakthrough threshold of calcium ion concentration in the effluent is set to 5 mg / L. When the calcium ion concentration in the effluent rises to the breakthrough threshold, the water intake is stopped and the solution is immediately switched to a dilute hydrochloric acid solution with pH=6.3. The solution is then passed through the glass adsorption column in reverse at a flow rate of 0.5 L / h for elution. Rinsing stage: After elution, switch to ultrapure water and rinse the glass adsorption column in the forward direction at a flow rate of 0.5 L / h until the pH value of the effluent stabilizes at 6.8-7.2, completing one regeneration cycle; Continue with low-hardness water to begin the next cycle of adsorption testing.

[0031] The above adsorption-regeneration cycle was repeated a total of 4 times. The regeneration performance and stability of the material were tested by observing the changes in adsorption time and calcium ion concentration at the outlet.

[0032] Application test results are as follows Figure 6 As shown, the adsorption material and regeneration process of this invention successfully achieved stable water treatment performance through 5 adsorption cycles and 4 regeneration cycles. Each water treatment cycle initially achieved a highly efficient deep hardening removal ([Ca²⁺]⁻) lasting up to 45 minutes. + The concentration of the sample was <1 mg / L, confirming that the adsorption and regeneration cycle technology can be reused multiple times under near-neutral pH conditions, which greatly reduces operating costs and has significant industrial application value.

[0033] Experimental tests showed that the preferred metal oxide in the mixed solution is bismuth oxide, with a dosage of 1 g / L to 10 g / L, and the optimal dosage is 1.5 g / L. The preferred concentration of the organophosphonate solution is 0.01 M to 0.1 M, and the preferred type of organophosphonate is aminotrimethylphosphonic acid (ATMP). The optimal pH value of the mixed solution is 9. The oven temperature is 125℃ and the heating time is 4 hours. The drying temperature in the forced-air drying oven is 55℃ and the drying time is 8 hours.

[0034] In summary, the present invention has the following advantages: (1) High efficiency and low alkali: It can work efficiently at pH 7.5 and above, which greatly reduces the amount of acid and alkali reagents added and reduces operating costs; (2) Deep purification: The surface-loaded organophosphonates can efficiently complex calcium ions, magnesium ions, etc. in water, and have a strong complexing and capturing ability for trace hardness ions. (3) Zero salt introduction: The hardening process does not rely on precipitants such as sodium carbonate, thus avoiding the problem of increased total dissolved solids in the effluent due to softening treatment; (4) Renewable and recyclable: After the adsorbent material is saturated, it can be regenerated by rinsing with a weak acid solution with a pH value of 6 to 6.5. No high-concentration waste acid or waste alkali solution is generated, the service life is long and the environment is friendly. (5) Easy to operate: It can be filled into glass adsorption columns, etc. The process is simple and easy to integrate into existing ultrapure water preparation systems.

[0035] The above description is merely an optional embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. An adsorbent material, characterized in that, The adsorbent material uses a metal oxide as a carrier, and the metal oxide is surface-functionalized by an organophosphonate containing multiple organophosphonic acid functional groups; wherein, some of the organophosphonic acid functional groups are bound to the surface of the metal oxide, and the remaining organophosphonic acid functional groups are modified on the surface of the metal oxide.

2. An application of an adsorbent material as a water treatment agent, characterized in that, The adsorbent material of claim 1, when used as a water treatment agent under water treatment conditions with a pH of 8 or above, allows the organophosphonate functional groups used for surface modification to bind with hardness ions in the water through complexation, thereby achieving deep hardness removal.

3. A preparation method suitable for preparing the adsorbent material according to claim 1, characterized in that, Includes the following steps: Step 1: Disperse the metal oxide in deionized water to form a suspension; Step 2: Add organophosphonates to the suspension and stir to mix, obtaining a mixture; Step 3: Measure a fixed amount of alkaline solution to adjust the pH of the mixture to 7.5-12, and then proceed with the hydrothermal reaction. Step 4: After the hydrothermal reaction is completed, the reaction products are subjected to solid-liquid separation, washing, drying and grinding to obtain the adsorbent material.

4. The preparation method according to claim 3, characterized in that, The metal oxides and metal hydroxides include one or more of bismuth oxide, aluminum oxide, iron oxide, ferrous oxide, and aluminum hydroxide.

5. The preparation method according to claim 3, characterized in that, In step one, the dosage of the metal oxide is 1 g / L to 10 g / L, based on the volume of deionized water.

6. The preparation method according to claim 3, characterized in that, In step one, if the metal oxide is a blocky solid, it needs to be ground in a ball mill for 10 minutes until a metal oxide powder of a predetermined particle size is obtained. The metal oxide powder is then dispersed in deionized water.

7. The preparation method according to claim 3, characterized in that, The organophosphonate in step two includes one or more of aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, and ethylenediaminetetramethylphosphonic acid. The concentration of the organophosphonate, calculated as phosphorus, is 0.01M to 0.1M.

8. The preparation method according to claim 3, characterized in that, The temperature of the hydrothermal reaction in step three is 100℃~150℃, and the reaction time is 1h~8h.

9. An application of an adsorbent material, characterized in that, include, Column packing: The adsorbent material is packed into an adsorption column; Hardness removal and effluent: The raw water to be treated is passed through the adsorption column for a certain empty bed contact time to perform deep hardness removal treatment and obtain purified effluent.

10. The application of the adsorbent material according to claim 9, characterized in that, It also includes, Regeneration of the adsorption column: When the concentration of hardness ions in the outlet water of the adsorption column reaches the set threshold, stop the water intake; use a dilute acid solution with pH=6-6.5 as the eluent, pass it through the adsorption column in either the reverse or forward direction to elute the complexed hardness ions, and then rinse with ultrapure water until the pH of the outlet water is neutral to complete the regeneration and restore the hardness removal performance.

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