A copper-loaded adsorbent, a preparation method and application thereof

Abstract

The present application relates to the field of environmental protection and wastewater treatment technology, and more particularly to a copper-loaded adsorbent, a preparation method and application thereof. The method comprises: pretreating zeolite; activating the pretreated zeolite; loading copper ions on the activated zeolite by using a solution containing copper ions to obtain a copper-loaded adsorbent precursor; and cleaning and drying the copper-loaded adsorbent precursor to obtain the copper-loaded adsorbent. The copper-loaded adsorbent not only has a high adsorption capacity and can significantly reduce the ammonia nitrogen concentration in wastewater in a short time, but also has good regeneration performance, which means that it can still maintain high adsorption capacity after multiple uses, thereby prolonging the service life and reducing the replacement frequency.

Description

Technical Field

[0001] This invention relates to the fields of environmental protection and wastewater treatment technology, and in particular to a copper-loaded adsorbent, its preparation method, and its application. Background Technology

[0002] In the context of environmental protection and sustainable development, wastewater treatment has become a crucial global issue. Particularly in industrial production and energy extraction, ammonia nitrogen levels in wastewater are a key pollution indicator, and their emission standards are strictly regulated by environmental regulations in various countries. This problem is particularly prominent in specific areas such as gas field water treatment and fracturing flowback fluids. Although physical treatment processes such as reverse osmosis or evaporation crystallization can remove most pollutants, ammonia nitrogen levels often still exceed emission standards, posing a potential threat to the environment.

[0003] These water samples typically have low chemical oxygen demand (COD), meaning low organic matter content, which poses a challenge for traditional biological treatment methods. Biological methods rely on organic matter as a food source for microorganisms to maintain their activity and decompose pollutants. However, in low-COD environments, microbial growth and metabolic activity are limited, leading to low efficiency in biological treatment and an inability to effectively remove ammonia nitrogen.

[0004] Therefore, developing a novel and efficient ammonia nitrogen adsorption material has become an urgent need in the field of wastewater treatment. Existing ammonia nitrogen removal technologies, such as chemical precipitation and stripping, can reduce ammonia nitrogen content to some extent, but these methods are often accompanied by high costs and complex operating procedures, and may generate new pollutants during the treatment process, causing secondary pollution problems, which runs counter to the concept of environmental protection and sustainable development.

[0005] Against this backdrop, finding an efficient, economical, and environmentally friendly ammonia nitrogen treatment technology has become particularly important. Summary of the Invention

[0006] To address the above problems, this invention provides a copper-loaded adsorbent, its preparation method, and its application. The invention provides the following technical solution:

[0007] This invention provides a method for preparing a copper-loaded adsorbent, the method comprising:

[0008] Pretreatment of zeolite;

[0009] The pretreated zeolite was then activated;

[0010] The activated zeolite was loaded with copper ions in a solution containing copper ions to obtain a copper-loaded adsorbent precursor.

[0011] The copper-loaded adsorbent precursor is cleaned and dried to obtain the copper-loaded adsorbent.

[0012] Furthermore, the zeolite undergoes pretreatment, including:

[0013] Select zeolite with a particle size of 0.5-2 mm;

[0014] The zeolite was rinsed with deionized water until the difference in water conductivity before and after rinsing was less than 5 μS / cm.

[0015] Further, the pretreated zeolite is activated, including:

[0016] The pretreated zeolite is calcined at a first predetermined temperature for a first predetermined time.

[0017] The calcined zeolite is then subjected to acid treatment for a second predetermined time.

[0018] The acid-treated zeolite is washed until neutral to complete the activation of the pretreated zeolite.

[0019] Furthermore, the acid treatment process includes:

[0020] The calcined zeolite is soaked in dilute hydrochloric acid or dilute nitric acid for a second predetermined time.

[0021] Furthermore, the first predetermined temperature is 450-600℃;

[0022] The first scheduled time is 2-4 hours;

[0023] The second scheduled time is 1-2 hours.

[0024] Furthermore, the activated zeolite is subjected to copper ion loading with a solution containing copper ions to obtain a copper-loaded adsorbent precursor, comprising:

[0025] The activated zeolite was loaded into an ion exchange column, and copper ion loading was achieved by passing it through a copper-containing solution at a predetermined flow rate until the copper ion concentration flowing into and out of the ion exchange column was consistent, thus obtaining the copper-loaded adsorbent precursor. The flow rate was selected as 1-3 BV / h.

[0026] Solutions containing copper ions include one of the following: copper sulfate solution, copper nitrate solution, or copper chloride solution;

[0027] The concentration of copper ions in the solution containing copper ions is 50-200 mg / L.

[0028] Further, the copper-loaded adsorbent precursor is cleaned and dried to obtain the copper-loaded adsorbent, including:

[0029] A deionized aqueous solution with a pH of 6-7 was passed into an ion exchange column containing a copper-loaded adsorbent precursor until the copper ion concentration in the outflowing deionized water was below 0.5 mg / L.

[0030] The cleaned copper-loaded adsorbent precursor was removed from the ion exchange column and dried at 40-60℃ for 24-72 hours to obtain the copper-loaded adsorbent.

[0031] A copper-loaded adsorbent prepared by the method described above is also provided, wherein the copper loading in the copper-loaded adsorbent is 0.2-0.5 mmol / g.

[0032] Applications of the copper-loaded adsorbent as described above are also provided, which are used to remove ammonia nitrogen from wastewater.

[0033] Furthermore, the wastewater to be treated is passed through an ion exchange column loaded with copper adsorbent, the wastewater flow rate is controlled at 0.6-2 BV / h, and the ammonia nitrogen concentration in the effluent is monitored periodically;

[0034] When the ammonia nitrogen concentration in the effluent reaches the predetermined value, the wastewater flow is stopped, and the copper-loaded adsorbent is regenerated.

[0035] Furthermore, the steps for regenerating the copper-loaded adsorbent include:

[0036] Use a 0.5-1% hydrochloric acid solution to pass through an ion exchange column containing the copper-loaded adsorbent to be regenerated at a rate of 1-2 BV / h until the pH of the effluent returns to neutral. Then wash the copper-loaded adsorbent with deionized water until the pH of the effluent is 6-7.

[0037] The technical effects and advantages of this invention are as follows:

[0038] This invention proposes a copper-loaded adsorbent technology. This material, based on natural zeolite, achieves highly efficient adsorption and removal of ammonia nitrogen from wastewater through a simple and cost-effective preparation method. The copper-loaded adsorbent not only possesses high adsorption capacity, significantly reducing ammonia nitrogen concentration in wastewater within a short time, but also exhibits excellent regeneration performance. This means it can maintain high adsorption capacity after multiple uses, thereby extending its service life and reducing replacement frequency.

[0039] Furthermore, the preparation and use of copper-loaded adsorbents do not generate secondary pollution, fully complying with environmental protection requirements, making them an environmentally friendly ammonia nitrogen adsorption material. Particularly noteworthy is the excellent performance of copper-loaded adsorbents in treating low-COD water samples after reverse osmosis or evaporation crystallization, effectively solving the problem of excessive ammonia nitrogen and providing a new solution for the treatment of various ammonia nitrogen-containing wastewaters, including industrial wastewater and domestic sewage. The application of this innovative technology can significantly improve the efficiency and effectiveness of wastewater treatment, contributing to environmental protection and the sustainable use of resources.

[0040] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0041] Figure 1 This is a flowchart of the method for preparing copper-loaded adsorbents provided in the embodiments of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] To address the shortcomings of existing technologies, this invention discloses a method for preparing a copper-loaded adsorbent, such as... Figure 1 As shown, the method includes:

[0044] Step 1: Pre-treat the zeolite;

[0045] Step 2: Activate the pretreated zeolite;

[0046] Step 3: The activated zeolite is loaded with copper ions in a solution containing copper ions to obtain a copper-loaded adsorbent precursor.

[0047] Step 4: Clean and dry the copper-loaded adsorbent precursor to obtain the copper-loaded adsorbent.

[0048] In one specific embodiment of the present invention, step 1: pretreatment of zeolite includes:

[0049] Step 101: Select zeolite with a particle size of 0.5-2 mm; preferably, natural zeolite is selected as the substrate, with its particle size controlled between 0.5-2 mm, to ensure that the zeolite has a large specific surface area, thereby improving its adsorption capacity. This particle size range is selected based on a comprehensive consideration of the zeolite's adsorption performance and fluid dynamics, aiming to achieve the best ammonia nitrogen removal effect.

[0050] Step 102: Rinse the zeolite with deionized water until the difference in conductivity before and after rinsing is less than 5 μS / cm. Thoroughly clean the zeolite with deionized water to remove surface impurities and soluble substances. The use of deionized water ensures that no new ions are introduced during the cleaning process, thus avoiding any impact on the zeolite surface properties. Measure the conductivity of the deionized water used for rinsing and compare it with the conductivity of the effluent after rinsing. If the difference is less than 5 μS / cm, the surface cleaning is considered complete. Natural zeolite may contain various impurities. Cleaning can remove most of these impurities. However, if other competing metal ions are present and not thoroughly cleaned, they may compete with specific metal ions during subsequent loading, reducing the adsorption capacity.

[0051] In one specific embodiment of the present invention, for step 2: activating the pretreated zeolite, the washed zeolite needs to undergo activation treatment to enhance its adsorption performance. The specific activation steps are as follows:

[0052] Step 201: Calcine the pretreated zeolite at 450-600℃ for 2-4 hours; preferably, calcine the zeolite at 550℃ for 2-4 hours. This process helps remove moisture and volatile substances from the zeolite pores, thereby increasing its porosity. During calcination, the structure of the zeolite changes, the pore structure is optimized, and some of the fillers in the zeolite pores, such as template agents, are removed during calcination. This process releases the internal space of the pores, increases the specific surface area of ​​the zeolite, strengthens the connectivity of the pores, improves the accessibility and diffusion performance of the channels, and exposes some active sites.

[0053] The initial predetermined temperature is 450-600℃. If zeolite is cooked at a low temperature below 400℃, its crystal structure usually remains stable, and the pore and cage-like structures also remain largely unchanged. The main process is to remove physically adsorbed water and some of the water of crystallization, but it does not significantly affect the framework and has limited impact on the optimization of the zeolite structure.

[0054] However, heating within the 450-650℃ range specified in this application can remove some fillers, such as template agents, during calcination. Simultaneously, as the temperature increases, slight dealuminization may occur, leading to an increase in the Si / Al ratio. This optimizes the acidic site distribution and ion exchange capacity of the zeolite. The pore size distribution also changes. This temperature range primarily affects the microporous structure, but the overall framework structure remains intact.

[0055] Step 202: Subject the calcined zeolite to acid treatment for a second predetermined time; preferably, soak the zeolite in 1M dilute hydrochloric acid or dilute nitric acid for 1-2 hours to further activate the zeolite surface and enhance its ion exchange capacity. Hydrochloric acid treatment removes metal oxides and other impurities from the zeolite surface, while simultaneously forming more negatively charged sites, providing conditions for copper ion loading. Appropriate calcination not only optimizes the pore size distribution and acidic sites of the zeolite but also provides ideal conditions for subsequent acid treatment. Acid treatment effectively removes metal elements (such as aluminum) from the zeolite, thereby increasing the Si / Al ratio and removing other impurity metals. If the calcination step is omitted or only a lower temperature is used for calcination, the pore structure will not be sufficiently optimized, and the effect of acid treatment will be significantly weakened. Step 203: Wash the acid-treated zeolite until neutral to complete the activation of the pretreated zeolite. The calcined and acid-treated zeolite needs to be washed with deionized water until neutral to remove residual acidic substances and ensure the chemical stability of the zeolite. This step ensures that the zeolite will not release acidic substances during subsequent use, thus avoiding secondary pollution to the environment.

[0056] In a specific embodiment of the present invention, step 3: loading the activated zeolite with a solution containing copper ions to obtain a copper-loaded adsorbent precursor includes:

[0057] Step 301: The activated zeolite is loaded into an ion exchange column, and copper ion loading is achieved by passing the solution containing copper ions through the column at a predetermined flow rate. The relationship between the flow rate and the copper ion concentration is set using an empirical formula.

[0058] Q = 0.7 × exp(0.0072 × [Cu] 2+ ])

[0059] In the formula, [Cu 2+ ] represents the concentration of copper ions in the solution, in mg / L; Q represents the flow rate, in BV / h, which is the bed volume passing through per hour.

[0060] Preferably, copper ion loading is performed by passing the copper sulfate solution with a copper ion concentration of 50-200 mg / L through a flow rate of 1-3 BV / h. This step is crucial for the preparation of the copper-loaded adsorbent, as the copper ion loading endows the zeolite with excellent ammonia nitrogen adsorption performance. Copper ions exchange with the negatively charged sites on the zeolite surface, forming a stable copper ion-loaded layer. Atomic absorption spectroscopy analysis shows that the copper content before loading is <0.002 mg / g, and after loading, the copper content reaches 15.3 mg / g.

[0061] It should be noted that zeolite can also be statically soaked directly in a solution containing copper ions, and homogenization can be improved by stirring or shaking to obtain a copper-loaded adsorbent precursor. However, this method requires a longer soaking time, and the diffusion rate of copper ions into the zeolite is slower. Therefore, parameters such as the temperature, pH, and soaking time need to be controlled during static soaking. This application preferably loads copper onto an ion exchange column after activation, which reduces the material preparation cost and makes it more economical in practical applications.

[0062] Step 302: Obtain the copper-loaded adsorbent precursor until the copper ion concentrations flowing into and out of the ion exchange column are consistent. The copper-containing solution includes one of copper sulfate, copper nitrate, or copper chloride solutions. The copper ion concentration in the solution is 50-200 mg / L. The copper ion loading process continues until the copper ion concentrations in the influent and effluent are detected to be consistent, indicating that the zeolite has reached its loading capacity. During this process, precise monitoring of the solution concentration is necessary to ensure that the zeolite loading reaches its optimal state.

[0063] In a specific embodiment of the present invention, step 4: cleaning and drying the copper-loaded adsorbent precursor to obtain the copper-loaded adsorbent includes:

[0064] A deionized water solution with a pH of 6-7 is passed through an ion exchange column containing a copper-loaded adsorbent precursor until the copper ion concentration in the effluent deionized water is below 0.5 mg / L. During this process, the copper-loaded zeolite is repeatedly rinsed with a large amount of deionized water, keeping the zeolite within the adsorption column. This rinsing is repeated with large amounts of deionized water until the copper ion concentration in the effluent is below 0.5 mg / L, ensuring a uniform distribution of copper ions on the zeolite surface and preventing environmental pollution. This step ensures that the zeolite does not release excessive copper ions during use, avoiding water pollution. Simultaneously, the pH of the effluent solution should be adjusted to approximately 6-7 during the rinsing process to ensure the stability and adsorption performance of the zeolite. pH adjustment is crucial for the stability of the zeolite; excessively high or low pH values ​​can affect the adsorption performance and lifespan of the zeolite.

[0065] The cleaned copper-loaded adsorbent precursor is removed from the ion exchange column and dried at 40-60°C for 24-72 hours to obtain the copper-loaded adsorbent. Preferably, the prepared copper-loaded adsorbent is dried at 50°C for 48 hours to remove moisture from the zeolite, enhance its mechanical strength and chemical stability, and allow copper ions to form stable complexes under suitable pH conditions. The final copper-loaded adsorbent product is then obtained. During the drying process, temperature and time must be carefully controlled to ensure that the zeolite structure is not damaged by over-drying.

[0066] The present invention also provides a copper-loaded adsorbent, which has the following characteristics:

[0067] High ammonia nitrogen adsorption capacity: The copper-loaded adsorbent of this invention has an ammonia nitrogen adsorption capacity of not less than 10 mg / g, which is far higher than that of commonly available adsorbents. This high adsorption capacity gives the copper-loaded adsorbent a significant advantage in treating high-concentration ammonia nitrogen wastewater.

[0068] Copper ion loading: The copper ion loading of the copper-loaded adsorbent is controlled within the range of 0.2-0.5 mmol / g. This range ensures the adsorption performance and stability of the zeolite. Precise control of the copper ion loading is crucial for the adsorption performance of the zeolite; too much copper ion may affect the structural stability of the zeolite, while too little may reduce its adsorption effect. The copper ion content in the zeolite after loading was directly determined by atomic absorption spectrometry. The experimental data on the copper content before and after loading were analyzed using atomic absorption spectrometry. Before loading, the copper content was <0.002 mg / g, and after loading, the copper content reached 15.3 mg / g.

[0069] Regeneration Performance: The copper-loaded adsorbent exhibits excellent regeneration performance. After each regeneration, its ammonia nitrogen adsorption capacity is no less than 80% of the initial value. Measurements showed that during the initial application, the adsorption capacity of this copper-loaded zeolite for ammonia nitrogen reached 34 mg / g. After five regenerations, the adsorption capacity still reached 31 mg / g. After the tenth regeneration, the adsorption capacity was 29.75 mg / g. After the twentieth regeneration, the adsorption capacity significantly decreased to 27.3 mg / unit, necessitating consideration of material replacement. This characteristic makes the copper-loaded adsorbent more economical in practical applications, reducing replacement frequency and lowering operating costs.

[0070] This invention also provides a copper-loaded adsorbent for the removal of ammonia nitrogen from wastewater.

[0071] 1) Wastewater treatment process

[0072] The wastewater to be treated is passed through an ion exchange column loaded with copper-loaded adsorbent, with the flow rate controlled at approximately 2-3 BV / h to ensure sufficient contact and adsorption of ammonia nitrogen in the wastewater with the zeolite. During the wastewater treatment process, the ammonia nitrogen concentration in the effluent needs to be monitored periodically to evaluate the adsorption effect of the copper-loaded adsorbent. This monitoring process is crucial for optimizing the wastewater treatment process and extending the lifespan of the copper-loaded adsorbent.

[0073] 2) Ammonia nitrogen concentration monitoring and copper-loaded adsorbent regeneration:

[0074] The ammonia nitrogen concentration in the water is monitored regularly. Once the predetermined value is reached, wastewater flow is stopped, and the copper-loaded adsorbent is regenerated. This step is crucial to ensuring the adsorption performance of the copper-loaded adsorbent. Timely regeneration can restore the adsorption activity of the copper-loaded adsorbent and prevent a decrease in ammonia nitrogen removal efficiency due to adsorption saturation.

[0075] The regeneration method for the copper-loaded adsorbent involves regenerating the bed volume (bed volume / hour) with an acidic solution at a rate of 1-2 BV / h. The specific operation is as follows:

[0076] A hydrochloric acid solution with a molar concentration of 0.1-0.5 mol / L is passed through the copper-loaded adsorbent layer at a rate of 1-2 BV / h until the pH of the effluent returns to neutral. The adsorbent is then rinsed with deionized water until the pH of the effluent reaches 6-7 to restore its adsorption activity. This regeneration process requires precise control of the concentration and flow rate of the hydrochloric acid solution to ensure that the performance of the copper-loaded adsorbent is not impaired by excessive acid washing.

[0077] Through the detailed preparation method and usage steps described above, this invention not only provides a highly efficient ammonia nitrogen adsorbent but also offers a new technological approach for wastewater treatment, contributing to achieving more environmentally friendly and economical wastewater treatment goals. The preparation and application of copper-loaded adsorbents not only solve the problem of excessive ammonia nitrogen but also avoid secondary pollution associated with traditional methods, meeting the requirements of sustainable development. Furthermore, the low cost and high efficiency of copper-loaded adsorbents make them promising for the treatment of various ammonia nitrogen-containing wastewaters, including industrial wastewater and domestic sewage. The application of this innovative technology can significantly improve the efficiency and effectiveness of wastewater treatment, contributing to environmental protection and the sustainable use of resources.

[0078] The copper-loaded adsorbent prepared in this invention exhibits excellent ammonia nitrogen adsorption performance. By precisely controlling the copper ion loading, a large number of active sites are formed on the zeolite surface. These sites can strongly interact with ammonia nitrogen molecules in wastewater, thereby achieving efficient adsorption. This high adsorption capacity makes the copper-loaded adsorbent perform excellently in treating high-concentration ammonia nitrogen wastewater, especially in water samples with low chemical oxygen demand (COD) after reverse osmosis or evaporation crystallization treatment, where its removal effect is particularly significant.

[0079] Another major advantage of copper-loaded adsorbents lies in their excellent regeneration performance. In wastewater treatment, the regeneration capacity of adsorbent materials directly affects their economic viability and practicality. Even after multiple regeneration treatments, the copper-loaded adsorbent of this invention maintains a high ammonia nitrogen adsorption capacity, which significantly extends the material's service life, reduces replacement frequency, and lowers long-term operating costs. This regeneration capability not only improves the economics of zeolite but also ensures the stable operation of wastewater treatment facilities.

[0080] Using natural zeolite as a substrate, this invention prepares a copper-loaded adsorbent through a series of simple and efficient steps. This method not only simplifies the preparation process but also significantly reduces the material preparation cost. Compared with traditional ammonia nitrogen removal materials, the copper-loaded adsorbent has a lower preparation cost, making it more competitive in the market and enabling wider applications.

[0081] In today's increasingly environmentally conscious world, the environmental friendliness of materials has become a crucial criterion for evaluating their quality. The copper-loaded adsorbent of this invention does not generate secondary pollution during its preparation and use, fully complying with environmental protection requirements. The use of this material does not impose an additional burden on the environment, making it a truly green material. Its application helps reduce the generation of chemical waste and mitigate negative environmental impacts.

[0082] The high efficiency and environmental friendliness of copper-loaded adsorbents make them promising candidates for various ammonia-nitrogen-containing wastewater treatment scenarios. Whether it's industrial wastewater, domestic sewage, or low-COD water samples after reverse osmosis or evaporation crystallization, copper-loaded adsorbents can effectively remove ammonia nitrogen, meeting stringent emission standards. The widespread application of this material not only improves wastewater treatment efficiency but also promotes the development of environmental protection technologies, contributing to the achievement of sustainable development goals.

[0083] In summary, the copper-loaded adsorbent and its preparation method of this invention have significant practical implications and broad market prospects in the field of wastewater treatment. It not only efficiently removes ammonia nitrogen from wastewater, reducing environmental pollution risks, but also boasts advantages such as low cost, easy regeneration, and environmental friendliness. With increasingly stringent environmental regulations and heightened public awareness of environmental protection, the application of copper-loaded adsorbents will bring revolutionary changes to the wastewater treatment industry, providing strong technical support for environmental protection and green development.

[0084] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0085] 1. Raw material preparation

[0086] In this embodiment, we first prepared the following raw materials:

[0087] Natural zeolite with a particle size of 0.5-2 mm was carefully selected. This size range is beneficial for increasing the specific surface area of ​​the zeolite, thereby enhancing its adsorption capacity. A 1 mol / L copper sulfate solution was prepared as a source of copper ions for loading the zeolite. This solution was used for cleaning and regeneration of the zeolite, ensuring the purity of the water during the treatment process.

[0088] 2. Preparation steps

[0089] 1) Zeolite cleaning:

[0090] The natural zeolite is thoroughly washed in deionized water to remove surface impurities and soluble substances. This step is crucial to ensure the purity of the zeolite surface, continuing until the wash water is clear and transparent, indicating that the zeolite has been cleaned.

[0091] 2) Zeolite activation:

[0092] The cleaned zeolite was divided into three groups and calcined in a muffle furnace at different temperatures for 3 hours each to remove moisture and volatile substances from the zeolite's pore structure and enhance its adsorption performance. After calcination, the zeolite was allowed to cool naturally to room temperature and then soaked in 1M dilute hydrochloric acid for 1.5 hours to further activate the zeolite surface and enhance its ion exchange capacity. Finally, the zeolite was washed with deionized water until neutral, with a pH of approximately 7, to ensure its chemical stability.

[0093] Nitrogen adsorption experiments were conducted using zeolite before and after calcination. High-purity nitrogen was used to conduct nitrogen adsorption and desorption experiments under conditions of saturated vapor pressure ratios of 0.05, 0.15, and 0.3.

[0094] Before calcination, saturated vapor pressure (P / P0) and adsorption capacity (cm³) 3 / g), desorption amount (cm) 3 / g), as shown in Table 1:

[0095] Table 1

[0096] Group number <![CDATA[Saturated vapor pressure (P / P0)]]> <![CDATA[Adsorption capacity (cm 3 / g)]]> <![CDATA[Desorption amount (cm 3 / g)]]> 1 0.05 <![CDATA[28 . 5]]> <![CDATA[27 . 8]]> 2 0.15 45.2 44.5 3 0.30 <![CDATA[62 . 1]]> <![CDATA[61 . 3]]> 4 0.45 73.2 70.6 5 0.60 83.6 80.3 6 0.75 92.2 90.6 7 0.90 97.4 96.6 8 0.95 98.2 97.5 9 1.00 98.2 97.2

[0097] After calcination at 200℃, the saturated vapor pressure (P / P0) and adsorption capacity (cm³) are... 3 / g), desorption amount (cm) 3 / g), as shown in Table 2:

[0098] Table 2

[0099]

[0100]

[0101] After calcination at 550℃, the saturated vapor pressure (P / P0) and adsorption capacity (cm³) are...3 / g), desorption amount (cm) 3 / g), as shown in Table 3:

[0102] Table 3

[0103] Group number <![CDATA[Saturated vapor pressure (P / P0)]]> <![CDATA[Adsorption capacity (cm 3 / g)]]> <![CDATA[Desorption amount (cm 3 / g)]]> 1 0.05 30.2 29.5 2 0.15 47.8 47.1 3 0.30 64.5 63.7 4 0.45 83.5 80.6 5 0.60 101 100.2 6 0.75 113.2 110.6 7 0.90 125.4 120.6 8 0.95 126.2 124.5 9 1.00 126.2 124.2

[0104] After calcination at 800℃, the saturated vapor pressure (P / P0) and adsorption capacity (cm³) are... 3 / g), desorption (cm) 3 / g), as shown in Table 4:

[0105] Table 4

[0106]

[0107]

[0108] A comparison of Table 1 and Table 2-4 shows that, under the same saturated vapor pressure, only the zeolite calcined at 550℃ exhibits improved adsorption capacity compared to the uncalcined zeolite. This indicates that calcination temperature significantly impacts the optimization of zeolite's specific surface area and pore structure. The calcination process at 550℃ increases the zeolite's nitrogen absorption, demonstrating that its specific surface area and pore structure are optimized.

[0109] According to Table 2-4, under the same saturated vapor pressure, the zeolite calcined at 550℃ exhibits the best adsorption performance at different calcination temperatures.

[0110] 3) Copper ion loading:

[0111] The activated zeolite was loaded into an ion exchange column and passed through a 1 mol / L copper sulfate solution at a rate of 1 mL / min to load copper ions. This step is crucial for the preparation of copper-loaded zeolite, as copper ions exchange with the active sites on the zeolite surface to form a stable copper ion-loaded layer. The loading process continued until the copper ion concentration in the effluent was consistent with that in the saturated solution, approximately 1 mol / L, indicating that the zeolite had reached its loading capacity. At this point, the copper-loaded adsorbent precursor was obtained.

[0112] 4) Cleaning and Validation:

[0113] The copper-loaded adsorbent precursor was repeatedly washed with large amounts of deionized water until the copper ion concentration in the effluent was below 0.5 mg / L, ensuring a uniform distribution of copper ions on the zeolite surface and preventing environmental pollution. At this point, the pH of the effluent solution was approximately 6–7, indicating the chemical stability of the zeolite.

[0114] 5) Drying:

[0115] The prepared copper-loaded adsorbent precursor was dried at 50°C for 48 hours to remove moisture from the zeolite, enhance its mechanical strength and chemical stability, and obtain the final product, the copper-loaded adsorbent.

[0116] 3. Ammonia nitrogen adsorption performance test

[0117] 1) Wastewater preparation:

[0118] A simulated wastewater with an initial ammonia nitrogen concentration of 50 mg / L was prepared to evaluate the adsorption performance of the copper-loaded adsorbent.

[0119] 2) Adsorption experiment:

[0120] The prepared copper-loaded adsorbent was loaded into an ion exchange column, and simulated wastewater was passed through the column at a flow rate of 2 mL / min. Ammonia nitrogen concentration in the water was periodically sampled and recorded, and the changes in adsorption time and ammonia nitrogen concentration were recorded to evaluate the adsorption efficiency and dynamic adsorption behavior of the copper-loaded adsorbent.

[0121] The adsorption experiment was conducted with an influent ammonia nitrogen concentration of 50 mg / L, a pH of 7.5, and a flow rate of 16.6 ml / L through the bed at a normal temperature of 25°C.

[0122] The adsorption column used was packed with approximately 500 mL of zeolite, weighing 883 g. During the adsorption experiment, the ammonia nitrogen concentration in the effluent was measured every 30 minutes. Once the ammonia nitrogen concentration reached 10 mg / L, wastewater flow was stopped, and regeneration was initiated. A 0.5% hydrochloric acid solution was passed through the copper-loaded adsorbent layer at a rate of 10.8 mL / min. The copper-loaded adsorbent was then washed with deionized water until the effluent pH reached 6–7. The adsorption experiment was repeated to evaluate the ammonia nitrogen adsorption performance of the regenerated copper-loaded adsorbent, verifying its regeneration capacity and the feasibility of long-term use. The total throughput was recorded, and the adsorption capacity of the zeolite was calculated.

[0123] The copper-loaded adsorbent was prepared by calcination at 200℃, and the adsorption experimental data are shown in Table 5.

[0124] Table 5

[0125]

[0126] The copper-loaded adsorbent was prepared by calcination at 550℃, and the adsorption experimental data are shown in Table 6.

[0127] Table 6

[0128]

[0129] The copper-loaded adsorbent was prepared by calcination at 800℃, and the adsorption experimental data are shown in Table 7.

[0130] Table 7

[0131]

[0132] 2) Regeneration performance:

[0133] As shown in Table 5-7, after 20 regeneration treatments, the ammonia nitrogen adsorption capacity of the copper-loaded adsorbent remained above 80% of its initial value, demonstrating excellent regeneration performance. Simultaneously, the proportion of copper in the zeolite did not change significantly, indicating that the copper ions in the copper-loaded adsorbent prepared in this invention have strong binding force with the zeolite and high stability. This characteristic makes the copper-loaded zeolite more economical and practical in real-world applications.

[0134] 3) Stability:

[0135] Under different pH values ​​(6-8) and temperatures (20-40℃), after 20 adsorption-desorption applications, the copper content decreased by 15%, demonstrating stable adsorption performance of the copper-loaded adsorbent, making it suitable for various practical wastewater treatment scenarios. This stability indicates that the copper-loaded adsorbent can maintain its high-efficiency ammonia nitrogen removal capacity under varying environmental conditions.

[0136] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a copper-loaded adsorbent, characterized in that, The method includes: Pretreatment of zeolite; The pretreated zeolite was then activated; The activated zeolite was loaded with copper ions in a solution containing copper ions to obtain a copper-loaded adsorbent precursor. The copper-loaded adsorbent precursor is cleaned and dried to obtain the copper-loaded adsorbent.

2. The method for preparing the copper-loaded adsorbent according to claim 1, characterized in that, Pretreatment of zeolite includes: Select zeolite with a particle size of 0.5-2 mm; Rinse the zeolite with deionized water until the difference in water conductivity before and after rinsing is less than 5 μS / cm.

3. The method for preparing the copper-loaded adsorbent according to claim 1, characterized in that, Activation of the pretreated zeolite includes: The pretreated zeolite is calcined at a first predetermined temperature for a first predetermined time. The calcined zeolite is then subjected to acid treatment for a second predetermined time. The acid-treated zeolite is washed until neutral to complete the activation of the pretreated zeolite.

4. The method for preparing the copper-loaded adsorbent according to claim 3, characterized in that, The acid treatment process includes: The calcined zeolite is soaked in dilute hydrochloric acid or dilute nitric acid for a second predetermined time.

5. The method for preparing the copper-loaded adsorbent according to claim 3, characterized in that, The first predetermined temperature is 450-600℃; The first scheduled time is 2-4 hours; The second scheduled time is 1-2 hours.

6. The method for preparing the copper-loaded adsorbent according to claim 1, characterized in that, The activated zeolite was subjected to copper ion loading with a solution containing copper ions to obtain a copper-loaded adsorbent precursor, including: The activated zeolite was loaded into an ion exchange column and passed through a solution containing copper ions at a predetermined flow rate to load copper ions until the concentration of copper ions flowing into and out of the ion exchange column was the same, thus obtaining a copper-loaded adsorbent precursor. The predetermined flow rate was 1-3 BV / h. The solution containing copper ions includes one of copper sulfate solution, copper nitrate solution, or copper chloride solution; the concentration of copper ions in the solution is 50-200 mg / L.

7. The method for preparing the copper-loaded adsorbent according to any one of claims 1-6, characterized in that, The copper-loaded adsorbent precursor is cleaned and dried to obtain the copper-loaded adsorbent, including: A deionized aqueous solution with a pH of 6-7 is passed into an ion exchange column containing a copper-loaded adsorbent precursor until the copper ion concentration in the outflowing deionized water is below 0.5 mg / L. The cleaned copper-loaded adsorbent precursor was removed from the ion exchange column and dried at 40-60℃ for 24-72 hours to obtain the copper-loaded adsorbent.

8. The copper-loaded adsorbent prepared by the preparation method according to any one of claims 1-7, characterized in that, The copper loading in the copper-loaded adsorbent is 0.2-0.5 mmol / g.

9. The application of the copper-loaded adsorbent as described in claim 8, characterized in that, Copper-loaded adsorbents are used to remove ammonia nitrogen from wastewater.

10. The application of the copper-loaded adsorbent as described in claim 9, characterized in that, The wastewater to be treated is passed through an ion exchange column loaded with copper adsorbent, and the wastewater flow rate is controlled at 0.6-2 BV / h. The ammonia nitrogen concentration in the effluent is monitored regularly. When the ammonia nitrogen concentration in the effluent reaches the predetermined value, the wastewater flow is stopped, and the copper-loaded adsorbent is regenerated.

11. The application of the copper-loaded adsorbent as described in claim 10, characterized in that, The steps for regenerating the copper-loaded adsorbent include: Use a 0.5-1% hydrochloric acid solution to pass through an ion exchange column containing the copper-loaded adsorbent to be regenerated at a rate of 1-2 BV / h until the pH of the effluent returns to neutral. Then wash the copper-loaded adsorbent with deionized water until the pH of the effluent is 6-7.

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