Copper-loaded activated carbon capable of simultaneously adsorbing acidic gas and alkaline gas, preparation method and application

Abstract

The invention discloses a preparation method of copper-loaded activated carbon capable of simultaneously adsorbing acidic gas and alkaline gas, which comprises the following steps: (1) uniformly mixing activated carbon with a nitric acid aqueous solution, and sequentially carrying out ultrasonic treatment and low-temperature stirring to obtain acid-modified activated carbon; (2) immersing the acid modified activated carbon into a copper chloride aqueous solution for modification treatment; and (3) sequentially carrying out low-temperature drying and high-temperature drying on the modified intermediate product to obtain the copper-loaded activated carbon. The preparation method disclosed by the invention does not need high temperature, and is simple in process, mild in condition and low in energy consumption; the prepared copper-loaded activated carbon has high loading capacity and high dispersity, and can efficiently remove acid and alkali gases with opposite properties at the same time; the composite material can be applied to odor adsorption and removal in various scenes such as wound care, stoma care, incontinence care, medical air purification, deodorization of home and public places, pet care, deodorization of food storage and processing environments, air purification of livestock and poultry farms, deodorization of garbage or sewage treatment and the like.

Description

Technical Field

[0001] This invention relates to the technical field of adsorption materials, and more particularly to a copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases, its preparation method, and its application in adsorbing and removing odors. Background Technology

[0002] Odor control is a critical challenge in many scenarios involving the decay or metabolism of organic matter, such as wound care, stoma care, incontinence care, livestock farming, and waste disposal. These odors are usually complex in composition, but their core odor-causing substances often include alkaline gases such as ammonia (NH3), cadaverine, and putrescine, as well as acidic sulfur-containing gases such as hydrogen sulfide (H2S) and methanethiol. Taking wound care as an example, the decomposition of wound exudate by microorganisms produces various acidic and alkaline malodorous molecules such as NH3, H2S, and methanethiol, which not only affect the patient's physical and mental comfort and quality of life, but may also indicate an infection risk.

[0003] Currently, activated carbon is widely used as an odor adsorption material in the aforementioned scenarios due to its high specific surface area, low cost, and good safety. However, unmodified activated carbon mainly relies on non-specific van der Waals forces for physical adsorption, which results in low adsorption capacity and poor selectivity for these polar small molecules, and easy desorption, leading to poor actual deodorization effect and frequent replacement of adsorption materials.

[0004] To enhance the adsorption capacity for polar molecules, activated carbon is often functionalized using acid-base modification strategies. This method can significantly improve the adsorption performance for a certain type of odor molecule. However, when faced with the above mixtures, the modified materials usually exhibit a strong selective adsorption tendency, leading to a "give-and-take" phenomenon in the adsorption of odor components with different properties—that is, while the adsorption of one type of gas is enhanced, the adsorption capacity for another type of gas with opposite properties is significantly weakened, making it difficult to achieve comprehensive purification of complex odor components.

[0005] On the other hand, metal-supported modification is also a promising method for functionalizing activated carbon. By introducing active metal centers such as copper, sites that can simultaneously interact with acidic and alkaline gases can be provided, achieving synergistic adsorption of mixed odor molecules. However, the application of this technology faces two limitations:

[0006] Firstly, its effectiveness is highly dependent on the loading and dispersion of the metal; improper loading can easily lead to insufficient active sites or particle agglomeration.

[0007] Secondly, existing processes often involve high-temperature steps. For example, Chinese patent document CN 112371087 A uses a method of impregnation followed by high-temperature calcination at 400–550°C. This method suffers from high energy consumption and high cost. Crucially, after this conventional high-temperature calcination, the copper salt is converted into copper oxide, which acts as an active center for removing hydrogen sulfide, phosphine, arsine, and ammonia. Its effect on hydrogen sulfide is mainly through direct chemical adsorption to form solid copper sulfide. This process is irreversible and easily clogs the carrier pores, leading to rapid material deactivation.

[0008] Therefore, how to construct metal active centers that can avoid pore blockage, have high dispersibility and suitable loading capacity through a simple and low-energy process to achieve efficient, long-lasting and synergistic removal of complex acidic and alkaline odor components is a prominent technical challenge. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention discloses a method for preparing copper-supported activated carbon. The process is simple, requires no high temperature, has mild reaction conditions, and low energy consumption. The prepared copper-supported activated carbon has high loading capacity and high dispersibility, enabling efficient removal of both acidic and alkaline gases with opposite properties. It can be applied to odor adsorption and removal in various scenarios such as wound care, stoma care, incontinence care, medical air purification, deodorization of homes and public places, pet care, deodorization of food storage and processing environments, air purification of livestock and poultry farms, and deodorization of garbage or sewage treatment.

[0010] The specific technical solution is as follows:

[0011] A method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases includes the following steps:

[0012] (1) The activated carbon was mixed evenly with nitric acid aqueous solution, and then subjected to ultrasonic treatment and low-temperature stirring in sequence to obtain acid-modified activated carbon;

[0013] The ultrasonic treatment time is 30-60 minutes;

[0014] The low-temperature stirring is carried out at 30~35℃;

[0015] (2) The acid-modified activated carbon is immersed in an aqueous solution of copper chloride for modification treatment;

[0016] (3) The intermediate product after modification in step (2) is subjected to low-temperature drying and high-temperature drying in sequence to obtain the copper-supported activated carbon;

[0017] The low-temperature drying is performed at a temperature of 40~60℃;

[0018] The high-temperature drying process takes place at a temperature of 80~120℃.

[0019] The preparation method disclosed in this invention includes acid modification and copper loading of activated carbon. The two modification methods exhibit the following synergistic mechanism: Nitric acid pretreatment (combined with ultrasonic treatment and low-temperature stirring) not only introduces abundant acidic oxygen-containing functional groups (such as carboxyl groups) on the activated carbon surface, directly enhancing the chemisorption of alkaline gas NH3; more importantly, these functional groups act as effective anchoring sites, significantly promoting the uniform dispersion and high loading of subsequent copper species. The copper loaded on this basis mainly exists in the form of highly dispersed copper chloride active species. This species not only enhances the adsorption of NH3 through complexation, but more importantly, its effect on H2S is dominated by catalytic oxidation, effectively avoiding pore blockage and irreversible deactivation caused by the formation of solid metal sulfides, thus achieving simultaneous and efficient removal of both acidic and alkaline gases with opposite properties. The two-stage drying process after copper loading—low temperature followed by high temperature—effectively reduces the migration and loss of copper chloride active components during the drying process.

[0020] Experiments revealed that during nitric acid pretreatment, if ultrasonic treatment alone is used, nitric acid is difficult to spread and react fully on the surface of activated carbon, resulting in low surface oxidation, insufficient introduction of functional groups, and poor dispersion of subsequent copper loading. If low-temperature stirring treatment alone is used, the nitric acid solution is difficult to penetrate quickly into the pores of activated carbon, resulting in uneven modification and concentrated distribution of functional groups, which also affects the anchoring and dispersion of copper species.

[0021] Further experiments revealed that if the drying process after copper loading is changed to a one-stage low-temperature drying or a one-stage high-temperature drying, it will lead to a large amount of migration and loss of the active components of copper chloride, reducing the copper content and affecting the final adsorption effect.

[0022] Experiments also revealed that the selection of raw materials for this preparation process is unique. If the nitric acid in the acid modification is replaced with other common acids in the field, such as sulfuric acid or hydrochloric acid, effective adsorption of acidic and alkaline gases cannot be achieved. If copper chloride is replaced with other common soluble copper salts in the field, such as copper nitrate, it will decompose to produce copper oxide during the subsequent drying process. When adsorbing acidic substances such as hydrogen sulfide, it not only fails to achieve the catalytic oxidation conversion as described in this invention, but also generates solid copper sulfide, thereby clogging the carrier pores and causing rapid deactivation of the modified activated carbon.

[0023] In step (1) of the present invention:

[0024] Preferably, the activated carbon is selected from one or more of biomass-derived activated carbon, mineral-derived activated carbon, and synthetic material-derived activated carbon;

[0025] Biomass-derived activated carbon includes coconut shell activated carbon, bamboo charcoal, wood charcoal, rice husk activated carbon, etc.

[0026] Mineral-based activated carbon, such as coal-based activated carbon and petroleum-based activated carbon;

[0027] Synthetic activated carbon sources include phenolic resin-based activated carbon and polyacrylonitrile-based activated carbon.

[0028] Preferably, the activated carbon is selected from materials with a mesh size of 20-40 and a specific surface area of ​​400-600 m². 2 / g of coconut shell activated carbon.

[0029] Preferably, the mass fraction of the nitric acid aqueous solution is 25-35%;

[0030] Preferably, the mass-to-volume ratio of activated carbon to nitric acid aqueous solution is 0.1~0.5 g / mL; more preferably, the mass-to-volume ratio of activated carbon to nitric acid aqueous solution is 0.1~0.3 g / mL; and even more preferably, it is 0.2 g / mL.

[0031] Preferably, the ultrasonic treatment is performed at room temperature;

[0032] Preferably, the low-temperature stirring is carried out at a stirring speed of 400~880 rpm for a time of 1~12 h;

[0033] Preferably, the crude product after low-temperature stirring needs to be filtered, washed and dried to obtain the acid-modified activated carbon.

[0034] In step (2) of the present invention:

[0035] Preferably, the concentration of the copper chloride aqueous solution is 1~6 mol / L; more preferably, the concentration of the copper chloride aqueous solution is 3.5~6 mol / L.

[0036] Preferably, the mass-to-volume ratio of acid-modified activated carbon to copper chloride aqueous solution is 0.1~0.5 g / mL; more preferably, the mass-to-volume ratio of acid-modified activated carbon to copper chloride aqueous solution is 0.1~0.2 g / mL.

[0037] Preferably, the modification treatment is performed at a temperature of 60-80°C for 1-5 hours.

[0038] Preferably, the modification process is accompanied by stirring at a speed of 400-880 rpm.

[0039] Preferably, the modified crude product is further subjected to filtration, washing and drying to obtain the intermediate product.

[0040] In step (3) of the present invention:

[0041] Preferably, the low-temperature drying time is 6-12 hours;

[0042] Preferably, the high-temperature drying time is 12-24 hours.

[0043] The present invention also discloses copper-supported activated carbon prepared according to the method, which simultaneously adsorbs acidic and alkaline gases.

[0044] Tests showed that the copper content in the copper-supported activated carbon prepared by this invention was 5.48~6.73 mg / g, and XRD characterization proved that the copper element was uniformly dispersed at the nanoscale.

[0045] The acidic gas includes hydrogen sulfide and / or methanethiol;

[0046] The alkaline gas includes ammonia and / or cadaverine.

[0047] Experiments have shown that the copper-supported activated carbon disclosed in this invention can simultaneously adsorb acidic and alkaline gases, and has excellent adsorption performance.

[0048] Based on the above performance, the present invention also discloses the application of the copper-supported activated carbon in adsorbing and removing odors.

[0049] Specific application scenarios include, but are not limited to: wound care, stoma care, incontinence care, medical air purification, deodorization of homes and public places, pet care, deodorization of food storage and processing environments, air purification of livestock and poultry farms, and deodorization of garbage or sewage treatment.

[0050] In this invention, the gas produced after fresh pork has been stored for 14 days is used as the source of odor. Tests show that the copper-supported activated carbon prepared in this invention effectively adsorbs both ammonia and hydrogen sulfide in the odor. In addition, in the comprehensive deodorization evaluation, this type of material also shows excellent purification effect on the overall odor, verifying its effectiveness in complex odor control scenarios.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) This invention discloses a method for preparing copper-loaded activated carbon. Acid pretreatment synergistically enhances the copper loading and dispersion. Nitric acid pretreatment not only improves the material's adsorption performance for alkaline gases such as ammonia but also promotes the uniform anchoring and highly dispersed loading of copper ions. Furthermore, the loaded copper component further strengthens its effect on acidic gases such as hydrogen sulfide. The two-step modification is functionally complementary and synergistic, enabling the material to simultaneously and efficiently remove both acidic and alkaline gases with opposite properties from odors. This preparation method eliminates high-temperature calcination throughout the process, instead employing a two-stage drying process—low temperature followed by high temperature—to replace high-temperature calcination. This effectively reduces the migration and loss of copper active components during drying, ensuring the loading effect while protecting the carrier structure. This method is mild, consumes significantly less energy than traditional processes requiring high-temperature treatment, and better preserves the pore structure of the activated carbon.

[0053] (2) The copper-supported activated carbon material prepared by this invention exhibits a significantly enhanced adsorption capacity and has good application potential. In particular, it has extremely high adsorption capacity for typical gases in odors such as NH3 and H2S. While possessing high adsorption capacity, this material also shows more stable performance potential in long-term use due to the highly dispersed morphology of copper species and the mild preparation process. Attached Figure Description

[0054] Figure 1 The image shows the Cu2p XPS diagram of the copper-supported activated carbon finally prepared in Example 1.

[0055] Figure 2 The XRD pattern of the copper-supported activated carbon finally prepared in Example 1 is shown, and the XRD patterns of the products of Comparative Example 1 and Comparative Example 2 are given for comparison.

[0056] Figure 3 For NH3 adsorption devices;

[0057] Figure 4 For H2S adsorption;

[0058] Figure 5 A device for testing the breakthrough of NH3 in the simultaneous adsorption of multiple components of gas;

[0059] Figure 6 A device for testing the penetration of H2S during the simultaneous adsorption of multiple components of gas;

[0060] Figure 7 The overall deodorization results are shown in the examples and some comparative examples. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially. The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0062] Example 1

[0063] Step (1): Prepare coconut shell activated carbon (mesh size 20-40 mesh, BET specific surface area 400-600 m²). 2 The activated carbon was placed in deionized water and washed at 600 rpm for 12 h at 25 °C, and then dried in an oven at 100 °C for 12 h to obtain pretreated activated carbon.

[0064] Step (2): Prepare a 30% nitric acid aqueous solution; mix the pretreated activated carbon with the nitric acid aqueous solution at a mass / volume ratio of 0.2 g / mL; first, sonicate at room temperature for 30 min, then place it on a magnetic stirrer and stir at a speed of 600 rpm and a temperature of 30℃ for 6 h; filter the solution after the reaction; then wash with deionized water until the pH of the filtrate is 6.5~7.0, and then dry it in an oven at 60℃ for 12 h to obtain nitric acid modified activated carbon.

[0065] Step (3): Prepare a copper chloride aqueous solution with a concentration of 3.8 mol / L. Mix the nitric acid modified activated carbon and the copper chloride aqueous solution at a mass / volume ratio of 0.1 g / mL. Place the mixture on a magnetic stirrer for modification. The stirring speed is 600 rpm and the temperature is 60℃. Stir for 2 h. Then filter the mixture and wash it with deionized water until no residual copper ions are present in the filtrate to obtain the intermediate product.

[0066] Step (4): Place the intermediate product in an oven and dry at 60°C for 6 hours, then at 100°C for 12 hours.

[0067] Figure 1 This is an XPS diagram of Cu2p of the product prepared in Example 1. According to this diagram, Cu2p... 3 / 2 The binding energy of the main peak is 933.8 eV, which is highly consistent with the characteristic peak position of copper chloride. At the same time, the intensity and distribution characteristics of its satellite peaks are also consistent with the typical XPS characterization results of copper chloride, which confirms that the copper species in the sample mainly exist in the form of copper chloride.

[0068] Figure 2The XRD pattern of the copper-supported activated carbon finally prepared in this embodiment shows that the sample is mainly composed of amorphous carbon with no obvious CuCl2 characteristic peak, indicating that the supported copper is uniformly dispersed in the activated carbon in the form of ultra-small crystals or in an amorphous state.

[0069] Example 2

[0070] The preparation process is basically the same as in Example 1, except that:

[0071] In step (2), the mass fraction of the nitric acid aqueous solution is replaced with 25%, and the low-temperature stirring temperature is replaced with 35℃;

[0072] In step (3), the concentration of the copper chloride aqueous solution is replaced with 1.8 mol / L.

[0073] Example 3

[0074] The preparation process is basically the same as in Example 1, with the only difference being:

[0075] In step (3), the concentration of the copper chloride aqueous solution is replaced with 5.7 mol / L.

[0076] Example 4

[0077] The preparation process is basically the same as in Example 1, with the only difference being:

[0078] In step (4), the drying conditions are replaced with drying at 40℃ for 12 h and drying at 120℃ for 24 h.

[0079] Comparative Example 1

[0080] Coconut shell activated carbon (mesh size 20-40 mesh, BET specific surface area 400-600 m²) 2 (g) is placed in deionized water, washed at 600 rpm for 12 h at 25°C, and then dried in an oven at 100°C for 12 h before use.

[0081] Comparative Example 2

[0082] Step (1): Prepare coconut shell activated carbon (mesh size 20-40 mesh, BET specific surface area 400-600 m²). 2 The activated carbon was placed in deionized water and washed at 600 rpm for 12 h at 25 °C, and then dried in an oven at 100 °C for 12 h to obtain pretreated activated carbon.

[0083] Step (2): Prepare a 30% nitric acid aqueous solution; mix the pretreated activated carbon with the nitric acid aqueous solution at a mass / volume ratio of 0.2 g / mL; first, sonicate at room temperature for 30 min, then place it on a magnetic stirrer and stir at a speed of 600 rpm and a temperature of 30℃ for 6 h; filter the solution after the reaction; then wash with deionized water until the pH of the filtrate is 6.5~7.0, and then dry it in an oven at 60℃ for 12 h to obtain nitric acid modified activated carbon for later use.

[0084] Comparative Example 3

[0085] Step (1): Prepare coconut shell activated carbon (mesh size 20-40 mesh, BET specific surface area 400-600 m²). 2 The activated carbon was placed in deionized water and washed at 600 rpm for 12 h at 25 °C, and then dried in an oven at 100 °C for 12 h to obtain pretreated activated carbon.

[0086] Step (2): Prepare a copper chloride aqueous solution with a concentration of 3.8 mol / L. Mix the pretreated activated carbon and the copper chloride aqueous solution at a mass / volume ratio of 0.1 g / mL. Place the mixture on a magnetic stirrer for modification. The stirring speed is 600 rpm and the temperature is 60℃. Stir for 2 h. Then filter the mixture and wash it with deionized water until no residual copper ions are present in the filtrate to obtain the intermediate product.

[0087] Step (3): Place the intermediate product in an oven and dry at 60℃ for 6 h, then at 100℃ for 12 h.

[0088] Comparative Example 4

[0089] Steps (1) to (2) are exactly the same as in Comparative Example 3;

[0090] Step (3): Place the intermediate product in a muffle furnace at 400℃ and calcine for 3 h.

[0091] Comparative Example 5

[0092] The preparation process is basically the same as in Example 1, with the only difference being:

[0093] In step (2), ultrasonic treatment was performed at room temperature for 30 minutes without further low-temperature stirring.

[0094] Comparative Example 6

[0095] The preparation process is basically the same as in Example 1, with the only difference being:

[0096] In step (2), the mixture was stirred at 600 rpm at 30°C for 6 h, without ultrasonic treatment at room temperature.

[0097] Comparative Example 7

[0098] The preparation process is basically the same as in Example 1, with the only difference being:

[0099] In step (4), the intermediate product was placed in an oven at 60°C and dried for 18 hours, but no high-temperature drying was performed.

[0100] Comparative Example 8

[0101] The preparation process is basically the same as in Example 1, with the only difference being:

[0102] In step (4), the intermediate product was placed in an oven at 110°C and dried for 18 hours. Low-temperature drying was not performed.

[0103] Performance testing:

[0104] (1) Adsorption of odorous gases separately

[0105] NH3 and H2S are two widely present gases in odorous gases, and their acidity and alkalinity are opposite, making them suitable as representative gases for adsorption studies. Figure 3 and 4 Two devices were used to adsorb NH3 and H2S at room temperature. The inlet gas was guaranteed to have an ammonia and hydrogen sulfide concentration of 50 ppm. Air was used as the carrier gas. The gas flow rate of each branch was 125 mL / min. The gas at the outlet was collected every 2 min using a 250 mL gas bag. The concentrations of ammonia and hydrogen sulfide in the gas at the outlet were measured using ammonia and hydrogen sulfide detectors, respectively, to calculate the adsorption amount. The calculation formula is shown in Equation (1).

[0106] (1)

[0107] In the formula, q is the amount of gas adsorbed by activated carbon, mg / g; Q is the air flow rate of each channel, mL / min; M is the molar mass of the target gas, 17 g / mol for NH3 and 34 g / mol for H2S; n is the total number of samplings, i.e., the total number of samplings from the start to adsorption saturation; c in,i and c out,i Δt represents the inlet and outlet gas concentrations at the i-th sampling time, in ppm; Δt represents the sampling time interval, in min; and m represents the activated carbon sample mass, in g.

[0108] The adsorption performance data of the modified activated carbon prepared in each embodiment and Comparative Examples 2-8 of this invention, as well as the activated carbon in Comparative Example 1 that underwent only impurity removal pretreatment, are shown in the figure.

[0109]

[0110]

[0111] The copper-supported activated carbon materials prepared in each embodiment all exhibited extremely high adsorption capacities for NH3 and H2S. Among them, the performance of Example 1 was the most outstanding, with its NH3 and H2S adsorption capacities increasing by 747% and 203% respectively compared to Comparative Example 1 (unmodified activated carbon), showing a very significant increase.

[0112] In contrast, Comparative Example 1 (unmodified activated carbon) lacks specific adsorption sites, and its adsorption relies entirely on physical processes, resulting in the lowest capacity. Comparative Example 2 (nitric acid modification only) improved the adsorption of NH3, but its adsorption of H2S was significantly reduced due to the excessively acidic surface, which severely inhibited the dissociation and transformation pathways of H2S, failing to meet the requirement for efficient adsorption of both gases simultaneously. Comparative Example 3 (direct copper loading without nitric acid pretreatment) lacked the anchoring effect of surface functional groups, resulting in poor copper species dispersion and low loading efficiency, thus limiting the improvement in adsorption performance. Comparative Example 4 (high-temperature calcination process) achieved a higher adsorption capacity, but this came at the cost of high energy consumption and a chemical adsorption pathway that could potentially cause pore blockage. In contrast, Example 1 of this invention achieved comparable or even better performance under milder conditions, highlighting the superiority of the process of this invention. Comparative Example 5 (ultrasonic treatment only) lacked a continuous low-temperature stirring reaction stage, making it difficult for nitric acid to fully spread and react on the activated carbon surface. This resulted in low surface oxidation and insufficient introduction of oxygen-containing functional groups, severely weakening its anchoring ability for subsequent copper ions and causing poor copper loading dispersion. Comparative Example 6 (low-temperature stirring treatment only) lacked prior ultrasonic pre-dispersion, making it difficult for the nitric acid solution to quickly penetrate into the pores of the activated carbon. This caused uneven modification reaction and concentrated functional group distribution, similarly failing to provide uniform and effective anchoring points for copper species. Therefore, although both examples were copper-loaded, their adsorption performance was significantly lower than the embodiment of this invention using the "ultrasonic-stirring" two-step synergistic acidification treatment, proving that this synergistic step is indispensable for constructing high-performance adsorbent materials. Comparative Example 7 (low-temperature drying only) failed to effectively fix the active components, while Comparative Example 8 (high-temperature drying only) caused copper ion migration and aggregation due to rapid initial moisture vaporization. Both resulted in significantly lower final adsorption performance, particularly the H2S adsorption capacity dependent on copper active sites, due to the loss or deterioration of active components during the drying process compared to the embodiment using a two-stage drying method of "low temperature first, then high temperature".

[0113] In summary, only by employing the process parameters claimed in this invention can copper-supported activated carbon materials with highly efficient synergistic adsorption capacity for NH3 and H2S be prepared. These materials exhibit high adsorption capacity for key components in complex odors.

[0114] (2) Chemical properties

[0115] The change in oxygen content on the surface of the material before nitric acid modification (Comparative Example 1) and after modification (Comparative Example 2) was determined using Boehm titration. The results are as follows: As shown, the increase in oxygen-containing groups such as carboxyl groups confirms that nitric acid modification has an oxidizing effect on the surface. The increased oxygen-containing groups can both enhance the chemisorption of NH3 and facilitate the loading of Cu elements in the later stage.

[0116] Table 2

[0117] * / indicates that no carboxyl groups were detected in the original activated carbon.

[0118] The Cu content in the products prepared in each example and comparative example was determined using ICP, and the results are as follows: As shown.

[0119] Table 3

[0120] As shown in Table 3, the copper content data indicates that the embodiments employing the complete process of this invention achieved a high loading level. The copper content of Comparative Example 3 (without nitric acid pretreatment) was significantly reduced, confirming the crucial anchoring effect of nitric acid pretreatment on copper ions. While the copper loading of Comparative Example 5 (ultrasonic treatment only) and Comparative Example 6 (stirring only) was higher than that of Comparative Example 3 without pretreatment, it was significantly lower than that of Example 1. This demonstrates that either ultrasonic or stirring treatment alone cannot replace the synergistic "rapid penetration-full reaction" effect, failing to provide sufficiently good and uniform anchoring points for copper loading, thus limiting the final loading. The copper content of Comparative Examples 7 and 8 (single low-temperature or high-temperature drying, respectively) was also significantly lower than that of Example 1, proving the necessity of the two-stage drying process—low temperature followed by high temperature—in reducing the loss of active components and achieving high loading. Although Comparative Example 4 also obtained a high copper content through high-temperature calcination, Example 1 achieved a considerable loading under mild conditions without the need for high temperature, while Example 3 significantly surpassed the high-temperature path under optimized parameters. This fully demonstrates that the present invention provides a superior path that can achieve high loading without relying on a high-temperature process, through "ultrasound-stirring synergistic acidification" and "two-stage drying".

[0121] (3) Simultaneous adsorption of multiple components of gases in odor

[0122] 3.1 Simultaneous Adsorption Experiment of Multi-component Gases

[0123] The gas produced by rotten pork (150 g of fresh pork placed at 25°C for 14 days) was used as the odor source for simultaneous adsorption experiments of NH3 and H2S. According to the literature "Freshness Evaluation of Three Kinds of Meats Based on the Electronic Nose," the main components of the odor produced by rotting pork include acetaldehyde, NH3, and H2S. A sealed container containing rotten pork was purged with air at 600 mL / min, causing the mixed gas to be split by a splitter and passed into adsorption tubes filled with 50 mg of different samples (i.e., the products prepared in the examples or comparative examples) or filled only with quartz wool. At the outlet of the adsorption tube, the penetration of NH3 and H2S was determined by phenolphthalein paper and lead acetate paper, respectively. A red color on the phenolphthalein paper indicated NH3 penetration, and a black color on the lead acetate paper indicated H2S penetration.

[0124] The adsorption breakthrough times of the products prepared in each embodiment and comparative example of the present invention are as follows: As shown in the figure. The results indicate that, compared to the comparative examples, the embodiments of the present invention can maintain a longer effective adsorption time for the key odor-causing gases NH3 and H2S in a mixed odor gas stream. This directly proves that, in the multi-component environment of real odors, the material of the present invention can still maintain a highly efficient simultaneous removal capability for key acidic and alkaline gases.

[0125] Table 4

[0126]

[0127] 3.2 Overall deodorization effect

[0128] 30 g of spoiled pork (150 g of fresh pork placed at 25°C for 14 days) was evenly divided into six centrifuge tubes. The tube openings were sealed with non-woven fabric (blank control) and non-woven fabric packages containing 1.5 g of different samples (i.e., products prepared in the examples or comparative examples). Subsequently, the centrifuge tubes were placed in six identical fly traps, and all fly traps were placed in an outdoor environment with an average daily temperature of approximately 25°C. The number of flies in the traps was observed and recorded for one week, and the number of flies was used as an evaluation index of the deodorization effect.

[0129] The comprehensive deodorization results of the products prepared in the embodiments of the present invention and Comparative Examples 1 (unmodified), 2 (acid-modified only), 4 (high-temperature calcination), 5 (ultrasound only), and 6 (stirring only) are as follows: As shown in the figure. The results indicate that the number of flies attracted by each embodiment of the present invention is significantly lower than that of Comparative Examples 1, 2, 5, and 6, while being comparable to that of Comparative Example 4, which underwent high-temperature calcination at 400℃. This directly proves that the copper-supported activated carbon prepared by the present invention through a mild process route has excellent comprehensive deodorization capabilities in real-world complex odor environments. Its effect is not only significantly better than that of incomplete modification paths, but also reaches the same level as traditional high-temperature processes with high energy consumption, thus highlighting the dual advantages of the present invention in terms of energy consumption and performance.

[0130] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. The specific examples used above to illustrate the present invention are only for the purpose of helping to understand the present invention and are not intended to limit the present invention. Those skilled in the art to which this invention pertains can make several simple deductions, modifications, substitutions, or combinations based on the concept of the present invention. These deductions, modifications, substitutions, or combinations also fall within the scope of the claims of the present invention.

Claims

1. A method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases, characterized in that, Includes the following steps: (1) The activated carbon was mixed evenly with nitric acid aqueous solution, and then subjected to ultrasonic treatment and low-temperature stirring in sequence to obtain acid-modified activated carbon; The ultrasonic treatment time is 30-60 minutes; The low-temperature stirring is carried out at 30~35℃; (2) The acid-modified activated carbon is immersed in an aqueous solution of copper chloride for modification treatment; (3) The intermediate product after modification in step (2) is subjected to low-temperature drying and high-temperature drying in sequence to obtain the copper-supported activated carbon; The low-temperature drying is performed at a temperature of 40~60℃; The high-temperature drying process takes place at a temperature of 80~120℃.

2. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (1): The activated carbon is selected from one or more of biomass-sourced activated carbon, mineral-sourced activated carbon, and synthetic material-sourced activated carbon. The mass fraction of the nitric acid aqueous solution is 25-35%; The mass-to-volume ratio of activated carbon to nitric acid aqueous solution is 0.1~0.5 g / mL.

3. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (1): The ultrasonic treatment was performed at room temperature; The low-temperature stirring is carried out at a speed of 400~880 rpm for a time of 1~12 h. The crude product after low-temperature stirring needs to be filtered, washed and dried to obtain the acid-modified activated carbon.

4. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (2): The concentration of the copper chloride aqueous solution is 1~6 mol / L; The mass-to-volume ratio of acid-modified activated carbon to copper chloride aqueous solution is 0.1~0.5 g / mL.

5. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (2): The modification treatment is performed at a temperature of 60-80℃ for 1-5 hours. During the modification process, stirring is performed at a speed of 400~880 rpm.

6. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (2): The modified crude product needs to be filtered, washed and dried to obtain the intermediate product.

7. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to claim 1, characterized in that, In step (3): The low-temperature drying process takes 6-12 hours. The high-temperature drying process takes 12 to 24 hours.

8. The method for preparing copper-supported activated carbon that simultaneously adsorbs acidic and alkaline gases according to any one of claims 1 to 7, characterized in that: In step (1), the activated carbon is selected from materials with a mesh size of 20-40 and a specific surface area of ​​400-600 m². 2 / g of coconut shell activated carbon; The mass-to-volume ratio of activated carbon to nitric acid aqueous solution is 0.1~0.3 g / mL; In step (2), the concentration of the copper chloride aqueous solution is 3.5~6 mol / L; The mass-to-volume ratio of acid-modified activated carbon to copper chloride aqueous solution is 0.1~0.2 g / mL.

9. A copper-supported activated carbon for simultaneously adsorbing acidic and alkaline gases, prepared by the method according to any one of claims 1 to 8, characterized in that: Acidic gases include one or more of hydrogen sulfide, methanethiol, and ethanethiol; Alkaline gases include one or more of ammonia, cadaverine, and putrescine.

10. The application of copper-supported activated carbon according to claim 9 in the adsorption and removal of odors.

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