Perovskite activator-loaded coconut shell activated carbon composite material, its preparation method and application

Abstract

The present invention relates to the technical fields of solid biomass waste recycling and biomass activated carbon preparation, and specifically relates to a perovskite activator-loaded coconut shell activated carbon composite material, a preparation method thereof, and an application thereof. The preparation method of the perovskite activator-loaded coconut shell activated carbon composite material is as follows: using coconut shell as a raw material to prepare coconut shell activated carbon; preparing LaCo 1‑x Mn x O3, wherein the molar ratio of lanthanum, cobalt, and manganese is 1:1 - x:x, and x is 0 to 1; loading LaCo 1‑x Mn x O3 on the coconut shell activated carbon to obtain the perovskite activator-loaded coconut shell activated carbon composite material. The preparation method of the present invention not only overcomes the problems in the prior art such as the need for additional electrolysis by power supply, high requirements for raw material ratios and complex ratios, and unsuitability for large-scale industrial production, but also realizes the efficient absorption of the harmful dye malachite green in printing and dyeing wastewater, and has important research significance and environmental protection application value.

Description

Technical Field

[0001] The present invention relates to the technical fields of solid biomass waste recycling and biomass activated carbon preparation, and particularly relates to a perovskite activator-loaded coconut shell activated carbon composite material, a preparation method thereof, and an application thereof. Background Art

[0002] With the acceleration of the industrialization process and environmental pollution, especially the problem of water resource pollution becoming increasingly prominent, among which dyeing wastewater has become an environmental problem to be solved urgently due to its complex composition and high toxicity. Malachite green commonly found in dyeing wastewater is a triphenylmethane dye, which poses a serious threat to aquatic organisms and human health. Traditional treatment methods often have limited effects when treating such wastewater, while the activated carbon adsorption method has received extensive attention due to its high efficiency and no secondary pollution. However, the high cost and non-renewability of commercially available activated carbon limit its wide application.

[0003] As an alternative to activated carbon, biochar has received extensive attention in the field of environmental remediation in recent years. Biochar-based materials have a wide range of sources, including rice husks, coconut shells, straw, livestock and poultry manure, sewage sludge, and agricultural waste. These materials are not only low-cost but also renewable. Among them, coconut shells have become an ideal choice for preparing biochar due to their large yield, high cellulose content, low ash content, and high mechanical strength. Coconut shell activated carbon not only maintains the basic characteristics of activated carbon, such as high specific surface area and porous structure, but also exhibits better adsorption performance due to the special composition of coconut shells. In the prior art, CN202010173132 discloses a modified coconut shell activated carbon used as a three-dimensional electrode filling particle, a preparation method thereof, and an application thereof. Activated carbon is prepared with coconut shells as the basic raw material, and modified coconut shell activated carbon is prepared with tetrabutyl titanate, isopropanol, and nitric acid as modifiers. The modified coconut shell activated carbon of the three-dimensional electrode filling particle prepared by this method has the characteristics of low price, stable performance, and good catalytic activity when treating organic wastewater, but additional power is required for electrolysis during the process of treating organic wastewater, consuming more energy, which has certain limitations on its application scenarios.

[0004] In addition, CN107758789A discloses the preparation and application of a printing and dyeing sewage treatment agent. Coconut shell powder is used as the raw material, soaked and calcined with a phosphoric acid solution, and modified coconut shell activated carbon is obtained by calcining with a copper nitrate solution and a cerium nitrate solution. Then, by adding polyferric trichloride, polyaluminum chloride, and modified bentonite materials, and mixing and granulating, a sewage treatment agent is obtained. This method can efficiently treat printing and dyeing sewage, but its raw materials are diverse and the ratio is complex, which is not suitable for large-scale industrial production. Summary of the Invention

[0005] In view of the deficiencies of the above-mentioned existing technologies, the present invention provides a perovskite activator-loaded coconut shell activated carbon composite material, its preparation method and application. First, the present invention uses La, Co and Mn metal salts as raw materials to prepare a perovskite activator by the sol-gel method; then uses coconut shells as raw materials to prepare activated carbon; and then loads the perovskite activator on the coconut shell activated carbon by the impregnation method to obtain a perovskite activator-loaded coconut shell activated carbon composite material. The preparation method of the present invention not only overcomes the problems in the existing technologies, such as the need for additional electrolysis by power supply, high requirements for the raw material ratio and complex ratio, and unsuitability for large-scale industrial production, but also realizes the efficient absorption of malachite green, a harmful dye in printing and dyeing wastewater, and has important research significance and environmental protection application value.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The first object of the present invention is to provide a preparation method of a perovskite activator-loaded coconut shell activated carbon composite material, including the following steps:

[0008] Using coconut shells as raw materials, prepare coconut shell activated carbon.

[0009] Using La, Co and / or Mn metal salts as raw materials, prepare perovskite activator LaCo 1-x Mn x O3, wherein the molar ratio of lanthanum, cobalt and manganese is 1:1 - x:x, x is 0 to 1, that is, both LaCoO3 and LaMnO3 are applicable to the present invention.

[0010] Load LaCo 1-x Mn x O3 on the coconut shell activated carbon to obtain a perovskite activator-loaded coconut shell activated carbon composite material, use the coconut shell activated carbon to adsorb malachite green, and use LaCo 1-x Mn x O3 to catalytically degrade malachite green.

[0011] Preferably, in the perovskite activator-loaded coconut shell activated carbon composite material, the mass percentage of LaCo 1-x Mn x O3 is 0.1wt% - 0.5wt%. If the mass percentage of the perovskite activator LaCo 1-x Mn x O3 is too high, it will reduce the adsorption activity of the perovskite activator-loaded coconut shell activated carbon composite material, deteriorate the adsorption performance, and increase the cost; if the mass percentage of the perovskite activator LaCo 1-x Mn x O3 is too low, it will reduce the adsorption activity and adsorption sites of the perovskite activator-loaded coconut shell activated carbon composite material, resulting in poor adsorption performance.

[0012] Preferably, the particle size of the coconut shell activated carbon is 60 mesh to 100 mesh. Among them, too small a particle size will reduce the amount of perovskite loaded. Although too large a particle size will increase the loading and adsorption area, the part that cannot be adsorbed in the center of the carbon particles becomes larger, resulting in a decrease in the utilization rate of the coconut shell activated carbon.

[0013] Preferably, the loading method is as follows: Wash the coconut shell activated carbon with deionized water to remove surface impurities, and then dry it to obtain treated coconut shell activated carbon; Disperse LaCo 1-x Mn x O3 in deionized water to obtain a LaCo 1-x Mn x O3 solution; Immerse the LaCo 1-x Mn x O3 solution into the treated coconut shell activated carbon, and let it stand to make LaCo 1-x Mn x O3 adhere to the surface of the activated carbon, and then dry it to obtain a perovskite active agent loaded coconut shell activated carbon composite material.

[0014] Preferably, the coconut shell activated carbon is prepared according to the following steps: After drying the coconut shell, heat it in a protective atmosphere at 700 °C to 1000 °C for 30 min to 120 min.

[0015] Preferably, LaCo 1-x Mn x O3 is prepared according to the following steps:

[0016] Mix lanthanum nitrate hexahydrate, citric acid, cobalt nitrate hexahydrate and / or manganese nitrate together in deionized water, and then adjust the pH to 8 - 9 with ammonia water to obtain a precursor solution; Heat the precursor solution and stir at 80 °C to 90 °C until a viscous gel is obtained; Calcinate the gel at 730 °C to 780 °C for 4 h to 6 h to obtain LaCo 1-x Mn x O3.

[0017] The second object of the present invention is to provide a perovskite active agent loaded coconut shell activated carbon composite material prepared by the above preparation method.

[0018] The third object of the present invention is to provide the application of the above perovskite active agent loaded coconut shell activated carbon composite material in the preparation of malachite green treatment agent.

[0019] Preferably, the application method is as follows: Add the perovskite active agent loaded coconut shell activated carbon composite material into the printing and dyeing wastewater, mix it by shaking, and use the perovskite active agent loaded coconut shell activated carbon composite material to adsorb and catalytically degrade malachite green in the printing and dyeing wastewater.

[0020] Preferably, the pH of the printing and dyeing wastewater is 4 - 10.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The present invention provides a preparation method of a perovskite active agent-loaded coconut shell activated carbon composite material. Using La, Co, and / or Mn metal salts as raw materials, the perovskite active agent LaCo 1-x Mn x O3 is prepared by the sol-gel method. Activated carbon is prepared from coconut shell as the raw material. Finally, the perovskite active agent is loaded on the coconut shell activated carbon to obtain the perovskite active agent-loaded coconut shell activated carbon composite material. The preparation method of the present invention not only overcomes the problems in the prior art such as the need for additional electrolysis by power supply, complex preparation process, high requirements for raw material ratio, and unsuitability for large-scale industrial production, but also realizes the efficient absorption of malachite green harmful dye in printing and dyeing wastewater, and has important research significance and environmental protection application value.

[0023] Among them, the main components of coconut shell include cellulose, hemicellulose, and lignin. Lignin is composed of phenylpropane units intertwined to form a complex three-dimensional polymer network. Due to its relatively high decomposition temperature of thermal polycondensation reaction, it has become a key component for manufacturing carbon materials. Moreover, coconut shell has low ash content, high density, and high mechanical strength. After carbonization, it forms a porous structure with a high specific surface area and abundant micropores. At the same time, coconut shell activated carbon has the characteristics of renewable, low cost, and environmental friendliness.

[0024] LaCo 1-x Mn x O3, as a perovskite-type oxide, has good catalytic activity. Loading LaCo 1-x Mn x O3 on coconut shell activated carbon can form a synergistic effect. On the one hand, the adsorption of coconut shell activated carbon can enrich the pollutant molecules in the wastewater, making them more easily catalytically degraded by the perovskite active agent; on the other hand, the catalytic action of the perovskite active agent can accelerate the degradation process of pollutants and improve the overall treatment efficiency. In addition, LaCo 1-x Mn x O3 has good chemical stability and thermal stability, and can maintain its catalytic activity within a wide range of temperatures and pH values.

[0025] Compared with the prior art, the perovskite active agent-loaded coconut shell activated carbon composite material of the present invention utilizes waste biomass, reduces the preparation cost; introducing the perovskite active agent greatly improves the adsorption performance, and its adsorption performance is superior to similar products, and its preparation process is simple and the cycle life is long.

[0026] 2. The perovskite active agent-loaded coconut shell activated carbon composite material of the present invention loads the perovskite active agent LaCo 1-x Mnx O3. The perovskite activator forms a porous structure with complex pores by single crystal grain accumulation, and there are active sites on the surface during the structure formation process. Through the design of the composite porous structure, the specific surface area of the composite material is greatly increased, the distribution range of active sites is expanded, harmful molecules in printing and dyeing wastewater are effectively captured, and it has excellent adsorption performance for malachite green harmful dyes in printing and dyeing wastewater.

[0027] 3. The present invention screened the conditions for the preparation of coconut shell activated carbon, adjusted the activation temperature and activation time, and effectively improved the adsorption capacity of coconut shell activated carbon for malachite green.

[0028] 4. The composite material of perovskite activator loaded on coconut shell activated carbon prepared by the present invention has good adsorption performance for malachite green in printing and dyeing wastewater and can effectively reduce the adsorption time of printing and dyeing wastewater. The main principles during the adsorption process are physical adsorption and chemical adsorption. Physical adsorption is determined by the specific surface area and pore distribution of coconut shell activated carbon, with low adsorption heat, fast adsorption rate, reversible process and no selectivity. Chemical adsorption is determined by the active sites on the pore surface of the composite material of perovskite activator loaded on coconut shell activated carbon, and is a chemical bond dominated by polar forces, including electron sharing, transfer between the composite material of perovskite activator loaded on coconut shell activated carbon and harmful molecules in printing and dyeing wastewater, and the decomposition of harmful molecules. Chemical adsorption usually only occurs in a single layer, has high endothermicity, shows selectivity, and is irreversible under normal temperature conditions, which makes the adsorption and desorption process of harmful molecules more complex.

[0029] LaCo 1-x Mn x O3 is loaded on the surface of coconut shell activated carbon. When the loading amount does not reach the saturation point of the surface monolayer, the amorphous structure usually has a large specific surface area and many active sites, which makes the contact between the perovskite activator LaCo 1- x Mn x O3 and coconut shell activated carbon more sufficient, thus improving the catalytic efficiency; while when the loading amount continues to increase and exceeds the saturation point of the surface monolayer of coconut shell activated carbon, the perovskite activator LaCo 1-x Mn x O3 begins to form a multi-layer structure or aggregates on the surface of coconut shell activated carbon, resulting in poor dispersion of LaCo 1-x Mn x O3 and thus reducing the catalytic efficiency. The aggregation of perovskite activator and pore blockage will lead to a decrease in catalytic efficiency. Description of the Drawings

[0030] Figure 1 It is a graph of the yield of the composite material of perovskite activator loaded on coconut shell activated carbon at different activation temperatures for Examples 1 to 4.

[0031] Figure 2 Adsorption effect diagrams of perovskite activator-loaded coconut shell activated carbon composites at different activation temperatures in Examples 1 to 4.

[0032] Figure 3 Yield diagrams of perovskite activator-loaded coconut shell activated carbon composites at different activation times in Examples 5 to 7.

[0033] Figure 4 Adsorption effect diagrams of perovskite activator-loaded coconut shell activated carbon composites at different activation times in Examples 5 to 7.

[0034] Figure 5 Adsorption effect diagram of the initial pH of printing and dyeing wastewater on the perovskite activator-loaded coconut shell activated carbon composite prepared in Example 6.

[0035] Figure 6 Adsorption effect diagrams of the coconut shell activated carbon prepared in Comparative Example 1 and the perovskite activator-loaded coconut shell activated carbon composite prepared in Example 6 under the same conditions. Detailed Description of the Invention

[0036] The following is a detailed description of the specific embodiments of the present invention. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0037] In the prior art, although various modification methods based on coconut shell activated carbon have been proposed and attempted to be applied to the treatment of printing and dyeing wastewater. For example, three-dimensional electrode filling particle modified coconut shell activated carbon prepared using tetrabutyl titanate as a modifier (CN202010173132), and a printing and dyeing sewage treatment agent prepared by combining modifiers such as phosphoric acid, copper nitrate, and cerium nitrate and various additives (CN107758789A). These methods have optimized the treatment efficiency or cost to varying degrees. However, the former increases energy consumption due to the need for an additional electrolysis process, which weakens its flexibility in practical applications; the latter brings challenges to large-scale industrial production due to the variety of raw materials and complex ratios, thus affecting its economy and practicality for wide promotion.

[0038] In view of the deficiencies of these prior arts, the present invention proposes a preparation method for a perovskite activator-loaded coconut shell activated carbon composite, which includes the following steps: using coconut shell as a raw material to prepare coconut shell activated carbon; preparing LaCo 1-x Mn xO3, where the molar ratio of lanthanum, cobalt, and manganese is 1:1 - x:x, and x ranges from 0 to 1; LaCo 1-x Mn x O3 is loaded onto coconut shell activated carbon to obtain a perovskite activator-loaded coconut shell activated carbon composite material.

[0039] In the present invention, first, perovskite activator is prepared by the sol-gel method using La, Co, and Mn metal salts as raw materials; then, activated carbon is prepared from coconut shell as the raw material, and the perovskite activator is loaded onto the coconut shell activated carbon by the impregnation method to obtain a perovskite activator-loaded coconut shell activated carbon composite material. Among them, due to the thermal polycondensation reaction characteristics of the lignin component in coconut shell, it is transformed into a key component of activated carbon during the carbonization process, endowing the perovskite activator-loaded coconut shell activated carbon composite material with excellent physical and chemical properties. And LaCo 1-x Mn x The loading of O3 on the surface of coconut shell activated carbon is efficiently distributed in an amorphous form before reaching saturated coverage, showing extraordinary catalytic activity.

[0040] Compared with the prior art, the preparation of the perovskite activator-loaded coconut shell activated carbon composite material in the present invention not only effectively utilizes waste biomass resources, greatly reduces production costs, but also significantly improves the adsorption performance of the perovskite activator-loaded coconut shell activated carbon composite material by introducing perovskite active components, exceeding similar products. At the same time, the preparation method is simple and fast, and the prepared perovskite activator-loaded coconut shell activated carbon composite material has a long cycle service life, providing an efficient, economical, and environmentally friendly solution for the field of printing and dyeing wastewater treatment.

[0041] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will specifically describe the technical solution of the present invention in detail with reference to specific embodiments:

[0042] Example 1

[0043] A preparation method of a perovskite activator-loaded coconut shell activated carbon composite material, comprising the following steps:

[0044] S1. Crush the coconut shell raw material, then place it in a constant temperature drying oven, and dry it at a temperature of 105°C for 24 hours to obtain dry coconut shell.

[0045] S2. Put the dry coconut shell into a crucible, then put the crucible into a horizontal pyrolysis furnace, continuously introduce nitrogen to isolate oxygen, and activate it at an activation temperature of 700°C for 30 minutes to obtain coconut shell activated carbon.

[0046] S3. Weigh lanthanum nitrate hexahydrate, cobalt nitrate hexahydrate, manganese nitrate, and citric acid, and dissolve them together in deionized water to obtain a precursor solution. Dropwise add ammonia water to the precursor solution and adjust the pH to 8.5. Then place it in a water bath and continuously heat and stir at 85 °C for 5 h until the precursor solution becomes a viscous gel. Place the gel in a muffle furnace and calcine it at 750 °C for 5 h to obtain a perovskite activator.

[0047] Among them, the molar ratio of lanthanum nitrate hexahydrate, cobalt nitrate hexahydrate, and manganese nitrate is 1:0.7:0.3, and the molar ratio of the total molar amount of lanthanum nitrate hexahydrate, cobalt nitrate hexahydrate, and manganese nitrate to citric acid is 1:1.5.

[0048] S4. Add the 80-mesh coconut shell activated carbon from step 2 to deionized water, stir at 60 °C for 0.5 h, filter, and rinse with deionized water. Repeat the above operation 10 times, and then dry at 100 °C for 12 h to obtain treated activated carbon.

[0049] Impregnate the LaCo 1-x Mn x O3 solution onto the treated activated carbon, let it stand for 6 h, and then dry it in a constant-temperature drying oven at 100 °C for 12 h to obtain a precursor.

[0050] S5. Calcine the precursor from step S4 at 350 °C for 5 h in an N2 atmosphere to obtain a perovskite activator-loaded coconut shell activated carbon composite.

[0051] Example 2

[0052] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite is the same as that in Example 1, except that the activation temperature is increased from 700 °C to 800 °C.

[0053] Example 3

[0054] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite is the same as that in Example 1, except that the activation temperature is increased from 700 °C to 900 °C.

[0055] Example 4

[0056] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite is the same as that in Example 1, except that the activation temperature is increased from 700 °C to 1000 °C.

[0057] The perovskite activator-loaded coconut shell activated carbon composite material is applied to the treatment of printing and dyeing wastewater. Using a 1 g / L malachite green solution as the simulated printing and dyeing wastewater, after measuring 10 mL of the malachite green solution, 10 mg of the perovskite activator-loaded coconut shell activated carbon composite material is added thereto. Then, the solution added with the perovskite activator-loaded coconut shell activated carbon composite material is sealed and placed in a constant temperature water bath shaker, and shaken at a rotation speed of 150 rpm and a temperature of 25 °C for 24 h. The perovskite activator-loaded coconut shell activated carbon composite material is used to adsorb malachite green. After the adsorption is completed, the malachite green solution is filtered using a syringe and a syringe filter, and the absorbance of the obtained filtrate is measured using a UV-visible spectrophotometer at a wavelength of 618 nm. After dilution, the concentration of malachite green in the solution after adsorption is calculated in combination with the standard curve.

[0058] Figure 1 It is the yield diagram of the perovskite activator-loaded coconut shell activated carbon composite material at different activation temperatures for Examples 1 to 4. As Figure 1 shown, when the activation temperature is 700 °C, the yield is 26.78%, and when the activation temperature is increased to 1000 °C, the yield drops to 25.70%. The yield decreases with the increase of the activation temperature.

[0059] Figure 2 It is the adsorption effect diagram of the perovskite activator-loaded coconut shell activated carbon composite material at different activation temperatures for Examples 1 to 4. As Figure 2 shown, during the process of increasing the activation temperature from 700 °C to 1000 °C, the adsorption capacity of the coconut shell-based biochar increases from 506.12 mg / g to 624.71 mg / g, but it drops to 604.55 mg / g at the activation temperature of 1000 °C.

[0060] Example 5

[0061] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite material is the same as that of Example 3, except that the activation time is increased from 30 min to 60 min.

[0062] Example 6

[0063] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite material is the same as that of Example 3, except that the activation time is increased from 30 min to 90 min.

[0064] Example 7

[0065] The preparation method of the perovskite activator-loaded coconut shell activated carbon composite material is the same as that of Example 3, except that the activation time is increased from 30 min to 120 min.

[0066] Example 8

[0067] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 6, except that in step S3, the gel is placed in a muffle furnace and calcined at 730 °C for 6 h.

[0068] Example 9

[0069] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 6, except that in step S3, the gel is placed in a muffle furnace and calcined at 780 °C for 4 h.

[0070] Example 10

[0071] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 1, except that in step S3, x is replaced by 0.5 from 0.3.

[0072] Example 11

[0073] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 1, except that in step S3, x is replaced by 0.7 from 0.3.

[0074] Example 11

[0075] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 1, except that in step S3, x is replaced by 1 from 0.3, and at this time the perovskite active agent is LaMnO3.

[0076] Example 12

[0077] The preparation method of the perovskite active agent-loaded coconut shell activated carbon composite is the same as the preparation steps of Example 1, except that in step S3, x is replaced by 0 from 0.3, and at this time the perovskite active agent is LaCoO3.

[0078] Comparative Example 1

[0079] A preparation method of coconut shell activated carbon includes the following steps:

[0080] S1. Crush the coconut shell raw material, and then place it in a constant temperature drying oven and dry it at a temperature of 105 °C for 24 h to obtain dry coconut shell.

[0081] S2. Put the dry coconut shell into a crucible, and then put the crucible into a horizontal pyrolysis furnace, continuously introduce nitrogen to isolate oxygen, and activate it at an activation temperature of 700 °C for 30 min to obtain coconut shell activated carbon.

[0082] The perovskite activator-loaded coconut shell activated carbon composite material is applied to the treatment of printing and dyeing wastewater. A malachite green solution with an initial concentration of 1 g / L is used to simulate the printing and dyeing wastewater. 10 mL of the malachite green solution is measured and 10 mg of the perovskite activator-loaded coconut shell activated carbon composite material is added. Then, the solution added with the perovskite activator-loaded coconut shell activated carbon composite material is sealed and placed in a constant temperature water bath shaker, and shaken at a rotation speed of 150 rpm and a temperature of 25 °C for 24 h. After the adsorption reaction is completed, the malachite green solution is filtered using a syringe and a syringe filter, and the absorbance of the obtained filtrate is measured by an ultraviolet spectrophotometer at a wavelength of 618 nm. After dilution, the concentration of the adsorbed solution is calculated in combination with the standard curve.

[0083] Figure 3 It is the yield diagram of the perovskite activator-loaded coconut shell activated carbon composite material under different activation times in Examples 5 to 7. As Figure 3 shown, during the process of extending the activation time from 30 min to 120 min, the yield of the biochar first increased from 25.93% to 26.07% and then slightly decreased to 26.06%, and increased to 26.07% again when the activation time was 120 min.

[0084] Figure 4 It is the adsorption effect diagram of the perovskite activator-loaded coconut shell activated carbon composite material under different activation temperatures in Examples 5 to 7. As Figure 4 shown, when the activation time was extended from 30 min to 120 min, the adsorption capacity of the perovskite activator-loaded coconut shell activated carbon composite material for the malachite green solution increased from 623.62 mg / g to 843.68 mg / g. When the activation time was 90 min, the adsorption capacity of the biochar was 827.24 mg / g, which was similar to the adsorption effect of the perovskite activator-loaded coconut shell activated carbon composite material with an activation time of 120 min.

[0085] Next, the adsorption performance under different pH conditions is studied:

[0086] Step 1: Use the malachite green solution to simulate the printing and dyeing wastewater, and gradually add sodium hydroxide solution to the malachite green solution with a concentration of 1.5 g / L to adjust the pH to 4, 6, 8, 10, and 12 respectively;

[0087] Step 2: Take 10 mL of the malachite green solution with different pH values, add 10 mg of the perovskite activator-loaded coconut shell activated carbon composite material to each solution, and place it in a constant temperature shaker, and shake it at 25 °C and 150 rpm for 24 h;

[0088] Step 3: After the adsorption process is completed, measure its absorbance to determine the adsorption effect.

[0089] Figure 5The figure shows the effect of the initial pH of printing and dyeing wastewater on the adsorption of the perovskite-activated agent-loaded coconut shell activated carbon composite prepared in Example 6. As Figure 5 shown, the adsorption capacity of the perovskite-activated agent-loaded coconut shell activated carbon composite for malachite green solution increases with the increase of pH. After pH > 8, the adsorption capacity of the perovskite-activated agent-loaded coconut shell activated carbon composite for malachite green tends to be stable, reaching more than 90%. When pH < 6, the adsorption capacity of the perovskite-activated agent-loaded coconut shell activated carbon composite for malachite green is small. With the increase of pH, the adsorption capacity of the perovskite-activated agent-loaded coconut shell activated carbon composite for malachite green increases from 718.63 mg / g at pH = 4.02 to 2174.58 mg / g at pH = 11.96.

[0090] The coconut shell activated carbon prepared in Comparative Example 1 and the perovskite-activated agent-loaded coconut shell activated carbon composite prepared in Example 6 were respectively applied to the treatment of printing and dyeing wastewater. The malachite green solution with an initial concentration of 1 g / L was used to simulate the printing and dyeing wastewater. 10 mL of the malachite green solution was respectively taken and placed in two clean reaction vessels. 10 mg of the perovskite-activated agent-loaded coconut shell activated carbon composite and 10 mg of coconut shell activated carbon were respectively added to the two vessels. Then the two vessels were sealed and placed in a constant temperature water bath oscillator. It was shaken at a rotation speed of 150 rpm and a temperature of 25 °C for 24 h. After the adsorption reaction was completed, the malachite green solution was filtered using a syringe and a syringe filter, and the absorbance of the obtained filtrate was measured by an ultraviolet spectrophotometer at a wavelength of 618 nm. After dilution, the concentration of the adsorbed solution was calculated in combination with the standard curve.

[0091] Figure 6 The figure shows the adsorption effect diagrams of the coconut shell activated carbon prepared in Comparative Example 1 and the perovskite-activated agent-loaded coconut shell activated carbon composite prepared in Example 6 under the same conditions. As Figure 6 shown, loading the perovskite-activated agent on the coconut shell activated carbon material can effectively improve the adsorption capacity of malachite green, and its adsorption capacity of malachite green is about twice that of the coconut shell activated carbon in Comparative Example 1. Under the same adsorption conditions, the adsorption capacity of the coconut shell activated carbon in Comparative Example 1 for malachite green is 1040.79 mg / g, and the adsorption capacity of the perovskite-activated agent-loaded coconut shell activated carbon composite for malachite green reaches 2174.57 mg / g.

[0092] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. Application of perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater, characterized in that: The perovskite active agent-loaded coconut shell activated carbon composite material was prepared according to the following steps: Coconut shell activated carbon is prepared using coconut shell as raw material; The perovskite active agent LaCo was prepared by sol-gel method using La, Co and Mn metal salts as raw materials. 1-x Mn x O3, wherein the molar ratio of lanthanum, cobalt and manganese is 1:1-x:x, x is 0 to 1, and x is neither 0 nor 1; LaCo 1-x Mn x O3 is loaded on coconut shell activated carbon to obtain a perovskite active agent loaded coconut shell activated carbon composite material.

2. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater according to claim 1, characterized in that: Perovskite active agent loaded coconut shell activated carbon composite material, LaCo 1-x Mn x The mass percentage of O3 is 0.1wt% to 0.5wt%.

3. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater according to claim 1, characterized in that: The particle size of coconut shell activated carbon is 60 mesh to 100 mesh.

4. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater according to claim 1, characterized in that: The load method is: The coconut shell activated carbon is washed with deionized water and then dried to obtain treated coconut shell activated carbon; LaCo 1-x Mn x O3 is dispersed in deionized water to obtain LaCo 1-x Mn x O3 solution; LaCo 1-x Mn x The O3 solution is impregnated onto the treated coconut shell activated carbon, and after standing and drying, a perovskite activator-loaded coconut shell activated carbon composite material is obtained.

5. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater according to claim 1, characterized in that: Coconut shell activated carbon was prepared according to the following steps: After the coconut shell is dried, it is heated at 700°C to 1000°C for 30min to 120min in a protective atmosphere.

6. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorbing malachite green in printing and dyeing wastewater according to claim 1, characterized in that: LaCo 1-x Mn x O3 was prepared as follows: Mixing citric acid, lanthanum nitrate hexahydrate, cobalt nitrate hexahydrate and manganese nitrate in deionized water, and then adjusting the pH to 8-9 with ammonia water to obtain a precursor solution; The precursor solution is heated and stirred at 80°C to 90°C until a viscous gel is obtained; The gel was calcined at 730℃~780℃ for 4h~6h to obtain LaCo 1-x Mn x O3.

7. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorption of malachite green in printing and dyeing wastewater according to claim 1, characterized in that: The application method is: The perovskite active agent loaded coconut shell activated carbon composite material is added into the printing and dyeing wastewater, shaken and mixed, and the perovskite active agent loaded coconut shell activated carbon composite material is used to adsorb malachite green in the printing and dyeing wastewater.

8. The use of the perovskite active agent loaded coconut shell activated carbon composite material in adsorbing malachite green in printing and dyeing wastewater according to claim 7, characterized in that: The pH value of printing and dyeing wastewater is 4-10.

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