Supported lignin-semi-coke composite purification materials, their preparation methods and applications

Abstract

This application discloses a supported lignin-semi-coke composite purification material, its preparation method, and its application. The material uses a lignin-semi-coke composite carrier formed by the co-pyrolysis of coal and lignin to support alkali metal oxides and zinc oxide active components. During preparation, the composite carrier powder is added to an alkaline solution, heated, and stirred. Utilizing density differences, flotation separation, lignin activation, and alkali metal loading are simultaneously achieved. The upper effective components are collected, zinc acetate is added, and the mixture is kneaded and calcined under an inert atmosphere to obtain the final product. During this process, lignin simultaneously acts as a binder, a carbon skeleton reinforcement, and a dispersant for the active components. This material exhibits high purification performance for H2S, SO2, volatile organic compounds, and heavy metal ions over a wide temperature range. Its mechanical strength is 20%–30% higher than that of pure semi-coke, and it maintains stable operation over long periods. It can be used for gas purification, wastewater treatment, and soil remediation, offering advantages such as high process integration, low cost, and environmental friendliness.

Description

Technical Field

[0001] This application relates to the field of composite purification materials technology, and in particular to a supported lignin-semi-coke composite purification material, its preparation method and application. Background Technology

[0002] Porous materials such as activated carbon and zeolite are widely used in gas adsorption and wastewater treatment, but they have the following technical drawbacks:

[0003] 1. Activated carbon: mainly microporous (pore size <2nm), with limited adsorption capacity for macromolecular pollutants (such as tar and polycyclic aromatic hydrocarbons); it mainly uses physical adsorption as the mechanism, and its adsorption performance drops sharply (usually by more than 80%) under high temperature conditions above 150°C; it needs to be prepared by high temperature steam or chemical activation, which is energy-intensive and highly polluting.

[0004] 2. Commercial zinc oxide desulfurizers: mainly composed of granular pure ZnO, but due to the resistance of mass transfer and diffusion, the ZnO utilization rate is usually less than 30%, and the sulfur capacity is only 8%~12%. In order to meet the stringent requirements of Fischer-Tropsch synthesis, methanation and other processes for the sulfur content of raw gas <0.1ppm, two-stage zinc oxide beds are often required in series, which leads to a significant increase in equipment investment and operating costs. Moreover, they are prone to sintering and deactivation at high temperatures and have poor recycling performance.

[0005] 3. Existing semi-coke materials: Most are directly used as fuel or low-end adsorbents, and have not been functionalized for gas purification and heavy metal removal.

[0006] In recent years, the preparation of high-performance purification materials using industrial waste and biomass resources (such as lignin, a byproduct of fuel ethanol and bio-based chemical production) has become a research hotspot. For example, Chinese invention patent CN120924299A discloses a method based on hydrothermal-forming pretreatment to enhance the synergistic effect of co-pyrolysis. This method uses oil-rich coal and enzymatically hydrolyzed lignin as raw materials, and obtains pyrolysis tar, pyrolysis gas, and solid semi-coke through CaO-catalyzed hydrothermal pretreatment, roll forming, and co-pyrolysis reaction. This method primarily aims to obtain liquid and gaseous products (tar and pyrolysis gas), while the solid semi-coke is only a pyrolysis byproduct, with its pores mainly consisting of micropores. It does not possess active functional components for gas purification and heavy metal removal.

[0007] Furthermore, Chinese invention patent CN115445588A discloses a biomass-based porous carbon composite material and its preparation method. This method uses black liquor solids from pulping and papermaking as a precursor, utilizing the alkali and sodium salt contained therein as template agents and activators, and obtains a porous carbon material with both physical and chemical adsorption functions through one-step carbonization by electric arc treatment. However, this method relies on the inherent inorganic alkali components in the black liquor raw material to provide alkaline sites, and the types and contents of active components are greatly affected by fluctuations in the raw material composition, making it difficult to flexibly control according to purification requirements. The product obtained by electric arc treatment is a powder, which has problems such as large bed pressure drop and easy loss by airflow when applied to gas purification scenarios such as fixed beds. Moreover, the functional verification of this material mainly focuses on the adsorption of CO2 as a single gas, and there is still a lack of research on its multifunctional purification performance in complex pollution systems such as H2S, SO2, volatile organic compounds, and liquid heavy metal ions.

[0008] Therefore, in the existing technology, the solid products obtained from the co-pyrolysis of coal and lignin are mostly used as fuels or low-value-added adsorbents, and their pore structure and surface chemical properties have not been effectively controlled; while the application of lignin as a carbon-based precursor is mostly concentrated in the preparation of powdered carbon materials, and the products obtained still have room for improvement in terms of molding strength, multifunctional purification adaptability, etc. Summary of the Invention

[0009] This application provides a supported lignin-semi-coke composite purification material, its preparation method, and its application. The material uses a lignin-semi-coke composite carrier formed by the co-pyrolysis of coal and lignin to support alkali metal oxides and zinc oxide active components. The abundant oxygen-containing functional groups on the carrier surface promote the uniform dispersion of the active components. The material possesses both chemical and physical adsorption capabilities, effectively removing gaseous pollutants such as H2S, SO2, and volatile organic compounds, as well as Pb, over a wide temperature range. 2+ Cd 2+ Hg 2+ All heavy metal ions exhibit efficient and stable purification performance, and demonstrate good mechanical strength and cycle regeneration stability.

[0010] To achieve the above objectives, this application provides the following technical solution:

[0011] In the first aspect, this application provides a supported lignin-semi-coke composite multifunctional purification material, comprising:

[0012] A lignin-semi-coke composite carrier is prepared by co-pyrolysis of coal and lignin, wherein the amount of lignin added is 5% to 20% of the coal mass, and the surface of the lignin-semi-coke composite carrier has oxygen-containing functional groups.

[0013] In addition, the active components loaded on the surface of the lignin-semi-coke composite carrier, wherein the oxygen-containing functional groups are used to promote the uniform dispersion of the active components on the carrier surface, and the active components include alkali metal oxides and zinc oxide, and the loading of the active components is 5% to 20% based on the total mass of the material.

[0014] Furthermore, in the above technical solution, the lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke; the lateral compressive strength of the lignin-semi-coke composite carrier is 20%~30% higher than that of a pure semi-coke carrier; and the specific surface area of ​​the lignin-semi-coke composite carrier is 200~500 m² / g. 2 / g, pore volume 0.2~0.6cm 3 / g, with a mesopore ratio greater than 40% and a mesopore diameter range of 5~50nm.

[0015] Furthermore, the oxygen-containing functional group includes one or more of hydroxyl, carboxyl, and carbonyl groups.

[0016] Furthermore, the alkali metal oxide is K2O or Na2O.

[0017] Furthermore, the lignin is derived from one or more of the following: biomass hydrolysis residue, papermaking black liquor, and enzymatically hydrolyzed lignin.

[0018] Secondly, this application provides a method for preparing the above-mentioned supported lignin-semi-coke composite multifunctional purification material, comprising the following steps:

[0019] S1: Add lignin-semi-coke composite carrier powder to an alkali metal hydroxide solution, heat to 80~95℃, stir for 30~60 minutes to dissolve and activate lignin in the alkali solution, and load alkali metal ions onto the carrier surface; use density difference for flotation separation and collect the upper effective components.

[0020] S2: Add zinc acetate solution to the upper effective component, stir and knead to form a soft material, and then granulate it.

[0021] S3: After drying, calcination is carried out at 300~500℃ in an inert atmosphere for 1~4 hours to obtain the molded purification material;

[0022] The lignin can serve as a binder, a carbon skeleton reinforcement, and an active component dispersant. The phenolic hydroxyl and carboxyl groups provided by the lignin coordinate with the metal ions in the alkali metal hydroxide solution, promoting the uniform dispersion of the active component on the carrier surface.

[0023] Furthermore, in step S1, the alkali metal hydroxide solution is KOH or NaOH with a concentration of 0.5~2.0 mol / L.

[0024] Furthermore, in step S1, the flotation separation using density differences specifically includes: a lightweight lignin-semi-coke composite carrier is suspended or floated on the upper layer of the liquid phase, while dense inorganic impurities settle to the bottom of the liquid phase, and the effective components in the upper layer are collected by overflow or retrieval.

[0025] Furthermore, in step S2, the concentration of the zinc acetate solution is 0.5~1.5 mol / L.

[0026] Furthermore, in step S2, granulation is carried out by ball rolling granulation or extrusion granulation to control the particle size to 1~5mm.

[0027] Furthermore, in step S3, the inert atmosphere is a nitrogen or argon atmosphere; during the calcination process, alkali metal hydroxides are converted into alkali metal oxides, zinc acetate is decomposed into ZnO, and lignin is carbonized into an amorphous carbon skeleton structure.

[0028] Thirdly, this application provides a method for preparing a lignin-semi-coke composite carrier, wherein the lignin-semi-coke composite carrier is used in the preparation method of the above-mentioned supported lignin-semi-coke composite multifunctional purification material, comprising the following steps: mixing coal powder and lignin powder, and performing supercritical carbon dioxide dynamic cyclic pyrolysis at 280~320℃ and 8~20MPa to simultaneously carbonize lignin and coal, thereby forming a lignin-semi-coke composite carrier; wherein the amount of lignin added is 5%~20% of the coal mass.

[0029] Furthermore, in the above technical solution, the reaction time of the supercritical carbon dioxide dynamic cyclic pyrolysis is 1 to 4 hours.

[0030] Furthermore, a co-solvent is added during the supercritical carbon dioxide dynamic cyclic pyrolysis process, and the amount of the co-solvent added is 2% of the coal powder mass.

[0031] Furthermore, the lignin is derived from one or more of the following: biomass hydrolysis residue, papermaking black liquor, and enzymatically hydrolyzed lignin.

[0032] Fourthly, this application provides a lignin-semi-coke composite carrier, prepared by the above-described method. The lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke, and its surface has oxygen-containing functional groups. The lateral compressive strength of the lignin-semi-coke composite carrier is 20%–30% higher than that of a pure semi-coke carrier. The specific surface area of ​​the lignin-semi-coke composite carrier is 200–500 m² / s. 2 / g, pore volume 0.2~0.6cm 3 / g, with a mesopore ratio greater than 40% and a mesopore diameter range of 5~50nm; the oxygen-containing functional group includes at least one of hydroxyl, carboxyl and carbonyl groups.

[0033] Fifthly, this application provides an application of the aforementioned supported lignin-semi-coke composite multifunctional purification material in gas purification. Specifically, the gas to be treated includes one or more of H2S, SO2, HCl, CO2, volatile organic compounds, and light tar; the volatile organic compounds include one or more of benzene, toluene, and xylene; the steps of purifying the gas using the supported lignin-semi-coke composite multifunctional purification material include: loading the composite multifunctional purification material into a fixed-bed or fluidized-bed reactor, with a gas space velocity of 500~5000 h⁻¹. -1 The processing temperature is 25℃~700℃.

[0034] Sixthly, this application provides an application of the aforementioned supported lignin-semi-coke composite multifunctional purification material in wastewater treatment or soil remediation. Specifically, the wastewater and soil to be treated each contain heavy metal ions, including Pb. 2+ Cd 2+ Cu 2+ Ni 2+ Zn 2+ Hg 2+ As 3+ Cr 6+ One or more of the following;

[0035] The steps for treating the wastewater using the supported lignin-semi-coke composite multifunctional purification material include: adding the composite multifunctional purification material into the wastewater to be treated, with a solid-liquid ratio of 1:10 to 1:100, stirring for 0.5 to 3 hours at a stirring speed of 100 to 500 rpm, and a treatment temperature of 10°C to 80°C. The composite multifunctional purification material forms stable complexes with heavy metal ions through its oxygen-containing functional groups, thereby achieving complexation and stabilization of heavy metal ions.

[0036] The steps for treating and remediating the soil to be treated using the aforementioned loaded lignin-semi-coke composite multifunctional purification material include: mixing the composite multifunctional purification material with heavy metal contaminated soil at a mixing ratio of 1% to 5%, maintaining the soil moisture content at 20% to 40%, and curing for 7 to 30 days, during which the mixture is turned over regularly.

[0037] Compared with the prior art, this application has at least the following beneficial effects:

[0038] 1. The supported lignin-semi-coke composite multifunctional purification material provided in this application uses a lignin-semi-coke composite carrier formed by the co-pyrolysis of coal and lignin as a substrate. In this carrier, lignin carbon and semi-coke form a homogeneous structure through chemical bonding, significantly improving the material's mechanical strength compared to a pure semi-coke carrier. The abundant oxygen-containing functional groups on the carrier surface anchor alkali metal oxides and zinc oxide active components to the carrier surface through coordination, achieving highly uniform dispersion of active components and significantly improving their utilization rate. Because this material possesses a purification mechanism dominated by chemical adsorption and a carrier… With its well-developed mesoporous structure, this material maintains stable and efficient purification performance for various gaseous pollutants and heavy metal ions over a wide temperature range. Furthermore, because the active components are firmly loaded onto the carrier surface through chemical bonding and coordination, and the pore isolation effect of the mesoporous structure inhibits the sintering and agglomeration of the active components during high-temperature regeneration, the active components are not easily detached or deactivated by sintering after multiple use-regeneration cycles. The adsorption capacity and purification efficiency are well maintained. Therefore, this material has excellent cycle regeneration stability and long-term operational stability.

[0039] 2. In this application, the lignin-semi-coke composite carrier is formed by chemical bonding of lignin carbon and semi-coke to create a homogeneous structure, which increases the lateral compressive strength by 20% to 30% compared to a pure semi-coke carrier, significantly enhancing the material's resistance to breakage during fixed-bed loading and long-term operation; simultaneously, the carrier has a thickness of 200 to 500 m... 2 High specific surface area per g, 0.2~0.6 cm³ 3 With a rich pore volume of / g and a mesopore ratio of more than 40%, the mesopore size is concentrated in the range of 5~50nm. The abundant mesoporous structure not only provides an efficient channel for the rapid mass transfer of gas molecules, but also effectively accommodates macromolecular pollutants (such as tar and polycyclic aromatic hydrocarbons), avoiding the problem of rapid decay of adsorption capacity caused by pore blockage in traditional microporous materials, and ensuring that the material maintains stable purification performance in complex pollution systems.

[0040] 3. In this application, the oxygen-containing functional groups on the surface of the carrier chemically bond with alkali metal ions and zinc ions through coordination, uniformly anchoring the active components of K2O or Na2O and ZnO on the carrier surface, effectively improving the dispersion and utilization rate of the active components; at the same time, the lignin raw material is derived from industrial wastes such as biomass hydrolysis residue, papermaking black liquor or enzymatic hydrolysis of lignin, realizing the synergy of waste resource utilization and high-performance material preparation, and significantly reducing the cost of raw materials while endowing the material with excellent purification performance.

[0041] 4. This application provides a method for preparing a supported lignin-semi-coke composite multifunctional purification material, which integrates alkaline impregnation, flotation separation, lignin activation, and alkali metal loading into the same step. It utilizes the density difference between the composite carrier and inorganic impurities to simultaneously purify the effective components, eliminating the need for separate acid washing, water washing, and other impurity removal processes. This achieves loading, activation, and purification in one step, simplifying the process and reducing wastewater generation. Furthermore, after lignin is dissolved and activated in the alkaline solution, it acts as a natural binder, allowing the powder material to be directly bonded and formed, eliminating the need for external binders. During calcination, zinc acetate decomposes into ZnO, alkali metal hydroxides are converted into alkali metal oxides, and lignin is simultaneously carbonized into an amorphous carbon skeleton. The conversion of active components and the enhancement of the carbon skeleton are completed in a single calcination, resulting in high process integration and low energy consumption. Moreover, the phenolic hydroxyl and carboxyl groups provided by lignin coordinate with metal ions in the solution, ensuring uniform dispersion of the active components on the carrier surface at the molecular level and preventing agglomeration and deactivation of the active components during subsequent use.

[0042] 5. The supported lignin-semi-coke composite multifunctional purification material provided in this application can be used for gas purification. Its primary mechanism is chemical adsorption, which is based on chemical reaction bonding. The reaction rate increases with increasing temperature, overcoming the defect of activated carbon and other physical adsorption materials where the adsorption capacity drops sharply above 150℃. It maintains stable and efficient removal performance for volatile organic compounds such as H2S, SO2, HCl, CO2, and benzene compounds within a wide temperature range from room temperature to 700℃. The material is packed into a fixed-bed or fluidized-bed reactor with a gas space velocity of 500~5000 h⁻¹. -1 It can meet purification requirements under certain conditions, has high operational flexibility, and can be flexibly adapted to the waste gas treatment needs of different working conditions.

[0043] 6. The supported lignin-semi-coke composite multifunctional purification material provided in this application can be used for wastewater treatment. In wastewater treatment, this material utilizes oxygen-containing functional groups on the carrier surface to react with Pb... 2+ Cd 2+ Hg 2+ The material forms stable complexes with heavy metal ions, and the alkalinity of the material itself promotes the precipitation of heavy metal hydroxides or carbonates, thus achieving efficient removal of various heavy metal ions.

[0044] 7. The supported lignin-semi-coke composite multifunctional purification material provided in this application can be used for soil remediation. This material can be stabilized through adsorption (the porous structure of the material adsorbs heavy metal ions in the soil pore water), chemical precipitation (alkaline substances in the material increase the soil pH, promoting the precipitation of heavy metal hydroxides or carbonates), complexation (oxygen-containing functional groups on the surface of lignin / semi-coke form stable complexes with heavy metal ions), and redox reactions (responsible for Cr). 6+ The carbon matrix in the semi-coke can reduce it to low-toxicity Cr.3+ Through multiple synergistic mechanisms, the soil can be transformed into a stable state of mobile heavy metals (the content of mobile heavy metals is reduced by more than 80%), effectively reducing the leaching toxicity of heavy metals. The treated soil meets the environmental protection standards for industrial land, fill soil or greening soil. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application. For example, based on the technical concepts disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, and size ratios of certain units (components).

[0046] Figure 1 This is a process flow diagram of the preparation process of the supported lignin-semi-coke composite multifunctional purification material provided in this application, as one embodiment. Detailed Implementation

[0047] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] In the description of this application, unless otherwise stated, the terms "including", "comprising", "having", etc., also mean "not limited to" (certain units, components, materials, steps, etc.).

[0049] Example 1

[0050] This embodiment provides a supported lignin-semi-coke composite multifunctional purification material, comprising: a lignin-semi-coke composite carrier and active components loaded on the surface of the lignin-semi-coke composite carrier. The lignin-semi-coke composite carrier is prepared by supercritical carbon dioxide dynamic cyclic pyrolysis of coal and lignin at 280℃~320℃ and 8~20MPa. The amount of lignin added is 5%~20% of the coal mass. The surface of the lignin-semi-coke composite carrier has oxygen-containing functional groups, which promote the uniform dispersion of the active components on the carrier surface. The active components include alkali metal oxides (K2O or Na2O) and zinc oxide (ZnO), with the loading of the active components being 5%~20% of the total material mass.

[0051] In this application, the lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke. The lateral compressive strength of the lignin-semi-coke composite carrier is 20%–30% higher than that of a pure semi-coke carrier. The specific surface area of ​​the lignin-semi-coke composite carrier is 200–500 m². 2 / g, pore volume 0.2~0.6cm 3 / g, with a mesopore ratio greater than 40% and a mesopore diameter ranging from 5 to 50 nm. The oxygen-containing functional groups include one or more of the following: hydroxyl (-OH), carboxyl (-COOH), and carbonyl (-C=O).

[0052] In this application, the lignin is derived from one or more of the following: biomass hydrolysis residue, papermaking black liquor, and enzymatically hydrolyzed lignin.

[0053] The loaded lignin-semi-coke composite multifunctional purification material provided in this application has at least the following beneficial effects:

[0054] 1. Composite carrier enhancement effect: In the composite carrier prepared by co-pyrolysis of coal and lignin, lignin carbon and semi-coke form a homogeneous structure through chemical bonding. The mechanical strength of the molded material is increased by 20%~30% compared with pure semi-coke, and the wear rate is reduced by more than 30%.

[0055] 2. Highly dispersed active components: The oxygen-containing functional groups in lignin and K + Zn 2+ Coordination occurs, promoting uniform dispersion of active components on the carrier surface, with an active component utilization rate of >80%.

[0056] 3. Excellent gas purification performance: ZnO-supported materials have excellent H2S removal performance, with a sulfur capacity of 15%~20% and a breakthrough time that is more than 50% longer than that of commercial ZnO desulfurizers; K2O / Na2O-supported materials have efficient chemical adsorption capacity for acidic gases such as SO2 and HCl, with a removal rate of >95%.

[0057] 4. Wide Temperature Range Adaptability: The composite multifunctional purification material provided in this application utilizes chemical adsorption as the primary mechanism, maintaining stable and efficient removal performance of target pollutants within a wide temperature range of 150~700°C. Physical adsorption materials such as activated carbon experience a sharp decrease in adsorption capacity above 150°C due to weakened van der Waals forces. In contrast, the chemical adsorption of the material in this application is based on chemical reaction bonding, with the reaction rate accelerating with increasing temperature. Simultaneously, the mesoporous structure (5~50nm) of the semi-coke remains stable at high temperatures, preventing pore blockage, and the inorganic oxides loaded on the surface do not significantly decompose below 500°C, all contributing to the material's high-temperature stability.

[0058] 5. Excellent stability during long-term operation: In the composite multifunctional purification material provided in this application, alkali metal / zinc oxide is chemically bonded to the carrier surface, resulting in a strong bond that prevents detachment during long-term operation at high temperatures. Furthermore, the mesoporous structure of the semi-coke provides a stable dispersion carrier for the active components, and the pore isolation effect effectively inhibits the sintering and agglomeration of the active components. Fixed-bed breakthrough experiments show that the breakthrough time of the ZnO-supported material of this invention is more than 50% longer than that of commercial ZnO desulfurizers; after 10 adsorption-regeneration cycles, the adsorption capacity retention rate is >85%; after 500 hours of continuous operation, the retention rate of the material's main performance indicators is >85%.

[0059] 6. Excellent Adsorption Performance for Organic Pollutants: This material possesses a well-developed mesoporous structure (pore size 5-50 nm, proportion >40%), exhibiting excellent adsorption performance for organic pollutants such as benzene series compounds (benzene, toluene, xylene) and light tar. The dynamic adsorption capacity for benzene can reach 150-250 mg / g, and the adsorption capacity for tar can reach 300-500 mg / g. The aromatic ring structure on the material surface undergoes π-π stacking interaction with the benzene ring, while the hydrophobic surface enhances the affinity for hydrophobic organic compounds. Compared to activated carbon, the mesoporous structure of the composite purification material in this application has better adsorption capacity and regeneration performance for macromolecular tar, making it suitable for applications such as VOCs treatment in industrial waste gas and tar removal from coke oven flue gas.

[0060] 7. Excellent heavy metal removal performance: particularly effective for Pb removal. 2+ Cd 2+ Cu 2+ It exhibits good adsorption performance for heavy metal ions, with an adsorption capacity 2 to 5 times that of activated carbon; for Hg 2+ As 3+ For highly toxic heavy metals such as Cr, ZnO-supported materials can convert them into insoluble sulfides or arsenates, thus achieving stabilization; 6+ The carbon matrix in the semi-coke support can reduce it to low-toxicity Cr. 3+ This achieves detoxification and fixation.

[0061] 8. Significant cost advantages: The materials provided in this application use coal-based by-product semi-coke and biomass waste lignin as carriers, resulting in extremely low raw material costs; the active component loading is only 5%~20%, which is 70%~80% less than commercial pure oxide desulfurizers; the integrated molding loading process does not require external binders or multiple calcinations, and energy consumption is reduced by more than 30% compared to traditional processes.

[0062] Example 2

[0063] This embodiment provides a method for preparing the supported lignin-semi-coke composite multifunctional purification material described in Example 1. (See also...) Figure 1 This includes the following steps:

[0064] 1. Alkali metal loading, lignin activation, and flotation separation (four-in-one):

[0065] The lignin-semi-coke composite carrier powder was added to an alkali metal hydroxide solution and stirred to disperse it. The alkali metal hydroxide was KOH or NaOH with a concentration of 0.5~2.0 mol / L. The mixture was heated to 80~95°C and stirred for 30~60 minutes to dissolve and activate the lignin in the alkali solution, while the alkali metal ions were loaded onto the carrier surface.

[0066] Flotation separation based on density difference: lightweight porous composite support (density 0.5~1.0 g / cm³). 3 These are dense inorganic impurities (ash, quartz, etc., with a density of 2.5~3.0 g / cm³) suspended or floating on the upper layer of the liquid phase. 3 The components settle to the bottom of the system; the upper effective components are collected by overflow or scooping, thus achieving loading, activation and purification in one step.

[0067] 2. Zinc salt loading and molding:

[0068] Add zinc acetate (Zn(CH3COO)2) solution with a concentration of 0.5~1.5 mol / L to the upper effective component; continue stirring and kneading to form a soft material; use ball rolling granulation or extrusion granulation to shape the material, controlling the particle size to 1~5 mm.

[0069] 3. Drying and roasting:

[0070] Dry at 80-120°C for 2-6 hours;

[0071] Calcination at 300-500°C under an inert atmosphere (nitrogen or argon) for 1-4 hours;

[0072] During the roasting process, KOH / NaOH is converted into K2O / Na2O, zinc acetate is decomposed into ZnO (while generating CO2 and H2O), and lignin is carbonized into an amorphous carbon skeleton, thus obtaining the molded purification material.

[0073] In the preparation method of this composite multifunctional purification material, lignin plays the following three roles simultaneously: ① Binder: Alkali-activated lignin has high viscosity, which helps to bind the powder material into shape without the need for additional binders; ② Carbon skeleton reinforcement: After calcination, lignin carbonizes into amorphous carbon, forming a carbon skeleton reinforcement structure, which improves the mechanical strength of the material; ③ Active component dispersant: The phenolic hydroxyl groups and carboxyl groups in lignin react with K... + Zn 2+ Coordination occurs, promoting the uniform dispersion of active components on the carrier surface.

[0074] Compared with the prior art, the preparation method provided in this application has the following advantages:

[0075] 1. Integrated flotation separation: During the alkaline impregnation process, the effective components are simultaneously separated by flotation by utilizing the density difference between the lignin-semi-coke composite carrier and inorganic impurities. There is no need to set up separate impurity removal processes such as acid washing and water washing, which further simplifies the process and reduces production costs.

[0076] 2. The Triple Functions of Lignin: This application utilizes lignin simultaneously as a binder, a carbon skeleton reinforcement, and an active component dispersant, achieving synergistic effects of waste resource utilization and material performance improvement. Lignin originates from industrial wastes such as biomass hydrolysis residue and papermaking black liquor, resulting in extremely low (or even negative) costs, while simultaneously solving the problem of industrial lignin waste disposal.

[0077] 3. Integrated molding and loading: Alkali metal loading, flotation separation, lignin activation, zinc salt loading, molding and granulation, and lignin carbonization are integrated into the same process. No external binder is required, and multiple calcinations are not necessary. The process is short, energy consumption is low, and equipment investment is low.

[0078] 4. Green and environmentally friendly: Zinc acetate is used as the zinc source, and the roasting decomposition products are only ZnO, CO2 and H2O, with no toxic or harmful gas emissions; the whole process does not require strong acid etching of the carrier and no acid washing waste liquid is generated; lignin is a biomass waste, realizing the treatment of waste with waste.

[0079] Example 3

[0080] This embodiment provides a method for preparing a lignin-semi-coke composite carrier, which can be used in the preparation method of the supported lignin-semi-coke composite multifunctional purification material described in Example 2 above, and includes the following steps:

[0081] Coal powder and lignin powder are mixed and subjected to supercritical carbon dioxide dynamic cyclic pyrolysis at 280~320℃ and 8~20MPa (the reaction time of dynamic cyclic pyrolysis is 1~4 hours) to carbonize lignin and coal simultaneously, forming a lignin-semi-coke composite carrier; the amount of lignin added is 5%~20% of the coal mass.

[0082] In a preferred embodiment, a co-solvent is added during the supercritical carbon dioxide dynamic cyclic pyrolysis process, and the amount of co-solvent added is 2% of the coal powder mass. Specifically, the co-solvent can be n-hexane.

[0083] In this application, pulverized coal and lignin powder are co-pyrolyzed under supercritical carbon dioxide conditions. Supercritical CO2 possesses both the diffusivity of a gas and the solubility of a liquid, allowing it to penetrate deep into the raw material particles and promote uniform mixing and simultaneous carbonization of lignin and coal at the molecular level, forming a chemically bonded homogeneous composite carrier. Furthermore, the supercritical carbon dioxide dynamic cyclic pyrolysis reaction system ensures full contact between the material and the medium, resulting in uniform carbonization and a carrier with a uniform pore distribution and good batch-to-batch stability. Additionally, the lignin used in the carrier preparation process originates from industrial waste such as biomass hydrolysis residue, papermaking black liquor, or enzymatically hydrolyzed lignin, broadening the applicability of lignin raw materials and providing a technical approach for the resource utilization of lignin from different sources.

[0084] Example 4

[0085] This embodiment provides a lignin-semi-coke composite carrier, prepared by the method described in Example 3 above. The lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke, and the surface of the lignin-semi-coke composite carrier has oxygen-containing functional groups. The lateral compressive strength of the lignin-semi-coke composite carrier is 20%~30% higher than that of the pure semi-coke carrier; the specific surface area of ​​the lignin-semi-coke composite carrier is 200~500 m². 2 / g, pore volume 0.2~0.6cm 3 / g, with a mesopore ratio greater than 40% and a mesopore diameter range of 5~50nm; the oxygen-containing functional groups include at least one of hydroxyl, carboxyl and carbonyl groups.

[0086] In this application, the lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke. Its lateral compressive strength is 20%–30% higher than that of a pure semi-coke carrier, overcoming the shortcomings of traditional semi-coke materials such as low mechanical strength and easy breakage and pulverization during use. The carrier has a specific surface area of ​​200–500 m². 2 With a mesoporous content greater than 40%, the abundant mesoporous structure provides ample accessible surface area and efficient mass transfer channels for the subsequent loading of active components. The oxygen-containing functional groups such as hydroxyl, carboxyl, and carbonyl groups on the surface of the support provide active sites for the coordination and anchoring of alkali metal ions and zinc ions, making the support an ideal substrate for supported purification materials.

[0087] Example 5

[0088] This embodiment provides an application of the above-mentioned supported lignin-semi-coke composite multifunctional purification material in gas purification. The target pollutants it can remove include: sulfur-containing gases (H2S, SO2), acidic gases (HCl, NO). X ), greenhouse gases (CO2), volatile organic compounds (benzene, toluene, xylene and other benzene series compounds) and light tar.

[0089] The steps for purifying gas using this supported lignin-semi-coke composite multifunctional purification material include: loading the composite multifunctional purification material into a fixed-bed or fluidized-bed reactor, with a gas space velocity of 500~5000 h⁻¹. -1 Processing temperature: 150~700°C (for benzene series compounds, tar, etc., operation can be carried out at room temperature to 150°C).

[0090] Example 6

[0091] This embodiment provides an application of the above-mentioned supported lignin-semi-coke composite multifunctional purification material in wastewater treatment. Target heavy metal ions that can be removed from wastewater include: Pb. 2+ Cd 2+ Cu 2+ Ni 2+ Zn 2+ Hg 2+ As 3+ Cr 6+ Hg 2+ As 3+ Cr 6+ It belongs to highly toxic heavy metal ions.

[0092] The steps for treating the wastewater using this supported lignin-semi-coke composite multifunctional purification material include: adding the composite multifunctional purification material to the wastewater at a solid-liquid ratio of 1:10 to 1:100, stirring for 0.5 to 3 hours at a stirring speed of 100 to 500 rpm, and treating at a temperature of 10℃ to 80℃. The composite multifunctional purification material forms stable complexes with heavy metal ions through its oxygen-containing functional groups, thereby achieving the complexation and stabilization of heavy metal ions.

[0093] Example 7

[0094] This embodiment provides an application of the above-mentioned supported lignin-semi-coke composite multifunctional purification material in soil remediation. The soil to be treated contains heavy metal ions. The composite multifunctional purification material can be mixed with the heavy metal-contaminated soil at a mixing ratio of 1% to 5%, stirred evenly, and the soil moisture content maintained at 20% to 40%. The mixture should be cured for 7 to 30 days, with regular stirring (every 3 to 7 days) during the curing period to ensure sufficient contact between the material and the soil.

[0095] The composite multifunctional purification material in this application achieves heavy metal stabilization through the following mechanism:

[0096] ① Adsorption and fixation: The porous structure of the material adsorbs heavy metal ions from soil pore water.

[0097] ② Chemical precipitation: Alkaline substances in the material increase the soil pH, promoting the precipitation of heavy metal hydroxides or carbonates.

[0098] ③ Complexation stability: Oxygen-containing functional groups on the surface of lignin / semi-char form stable complexes with heavy metal ions.

[0099] ④ Redox: For Cr 6+ The carbon matrix in the semi-coke can reduce it to low-toxicity Cr. 3+ .

[0100] After maintenance, the content of mobile heavy metals in the soil is reduced by more than 80%, and the leaching toxicity meets the relevant environmental protection standards for industrial land, fill soil, or greening soil, providing an economical and effective solution for the safe utilization of contaminated soil.

[0101] Example 8

[0102] This embodiment provides a verification example of the preparation of a lignin-semi-coke composite carrier.

[0103] Take 500g of bituminous coal powder and add 75g of lignin powder (the amount added is 15% of the coal mass; the lignin is derived from biomass hydrolysis residue), and mix thoroughly. Load the mixture into a supercritical reactor, introduce CO2, heat to 300℃, pressurize to 15MPa, add 2% (by weight of coal) of n-hexane as a co-solvent, start the circulating compressor, and dynamically circulate the reaction for 2 hours. Depressurize and cool, and collect the lignin-semi-coke composite carrier.

[0104] The performance test results of the obtained composite carrier are as follows: specific surface area 385 m² 2 / g, pore volume 0.45cm 3 The carrier has a pergola density of 42%, a mesopore content of 8.2%, and a mechanical strength approximately 25% higher than that of pure semi-coke carriers. The carrier surface contains oxygen-containing functional groups, including hydroxyl, carboxyl, and carbonyl groups, introduced by lignin during co-pyrolysis. The mesopore size is concentrated in the range of 5–50 nm, and the abundant mesoporous structure provides ample accessible surface area and mass transfer channels for subsequent loading of active components.

[0105] Example 9

[0106] This embodiment demonstrates the process effect of simultaneously achieving flotation separation, lignin activation, and alkali metal loading during alkaline impregnation.

[0107] Take 100g of the lignin-semi-char composite carrier powder obtained in Example 8, add 300mL of 1.5mol / L KOH solution, and stir to disperse. Heat to 90℃, stir for 40 minutes, and let stand for 10 minutes. Observation shows that the upper layer is a suspended dark lignin-semi-char composite carrier, and the bottom layer is a light-colored precipitate (inorganic impurities). Collect the upper suspension through the overflow port, filter to obtain the purified carrier. Discard the bottom impurities.

[0108] Separation results: Carrier recovery rate 94%; Ash content before separation 8.2%, reduced to 1.8% after separation, removal rate 78%; Abrasion rate of subsequent molding materials before separation 2.5%, reduced to 1.6% after separation, mechanical strength increased by approximately 10%; K + Loading capacity 7.2% (comparable to the traditional impregnation method).

[0109] This embodiment illustrates that during the alkaline impregnation process, the density difference between the composite carrier and inorganic impurities allows for simultaneous flotation separation of the effective components, eliminating the need for separate acid washing, water washing, or other impurity removal processes. Simultaneously, lignin dissolves and activates in the hot alkaline solution, its molecular chains unfolding to form a high-viscosity solution, providing a binding foundation for subsequent molding. + During the impregnation process, the lignin is anchored to the carrier surface through the coordination of oxygen-containing functional groups on the lignin surface, thus achieving uniform loading of alkali metals.

[0110] Example 10

[0111] This embodiment demonstrates a complete process flow for preparing the final product (K2O+ZnO supported composite purification material) by using the effective components purified by flotation as raw materials, through zinc acetate kneading and molding, and integrated calcination.

[0112] Take approximately 100 g of the effective carrier (wet basis, dry basis) collected by flotation separation in Example 9, add 80 mL of 1.0 mol / L zinc acetate solution, and stir to form a soft material. Granulate using a ball granulator, controlling the particle size to 2-4 mm. Dry at 110 °C for 4 hours. Transfer to a muffle furnace and calcine at 450 °C under a nitrogen atmosphere for 3 hours to obtain spherical K₂O+ZnO supported composite purification material.

[0113] Molding material properties: Lateral compressive strength 95N; Specific surface area 342m² 2 / g; K2O content 6.8%; ZnO content 11.5%; ash content 1.5%; abrasion rate 1.5%; H2S breakthrough time (350℃, 100ppmH2S, space velocity 2000h) -1 ): 175 min; SO2 removal rate (200℃, 500ppmSO2): 97%; Pb 2+ Adsorption capacity: 96 mg / g.

[0114] This embodiment illustrates that zinc acetate, as a zinc source, decomposes into ZnO, CO2, and H2O during the roasting process, with no toxic or harmful gas emissions, making it environmentally friendly. The alkali-activated lignin acts as a binder during kneading, allowing the powder material to be directly shaped without the need for additional binders. A single roasting process simultaneously completes the conversion of alkali metal hydroxides to oxides, the decomposition of zinc acetate into ZnO, and the carbonization of lignin into an amorphous carbon skeleton, resulting in a high degree of process integration. The resulting material has an ash content of only 1.5%, indicating that flotation separation effectively removes inorganic impurities, which is beneficial for improving the material's mechanical strength and the utilization rate of active components.

[0115] Verification Example 1

[0116] This verification example tests the H2S removal performance of the material obtained in Example 10 and compares it with that of a commercial ZnO desulfurizer.

[0117] 1. Take 10g of the material prepared in Example 10 and pack it into a fixed-bed reactor (inner diameter 10mm). Introduce a N2 mixture containing 100ppm H2S at a space velocity of 2000h⁻¹. -1 The reaction temperature was 350℃. The H2S concentration in the outlet gas was detected by gas chromatography.

[0118] Results: Within 115 minutes after the start of the reaction, the outlet H2S concentration was <0.05ppm; the breakthrough time (outlet H2S concentration >0.1ppm) was 175 minutes; and the sulfur capacity (as ZnO) was 17.2%.

[0119] 2. Using commercial granular ZnO desulfurizer (ZnO content >95%), under the same conditions, the breakthrough time was 120 minutes and the sulfur capacity was 11.2%.

[0120] This verification example demonstrates that the sulfur capacity of the material in this application (17.2%) is significantly higher than that of commercial ZnO desulfurizers (11.2%), with a breakthrough time extended by more than 50%. This is attributed to two synergistic effects: firstly, the well-developed mesoporous structure of the support reduces the mass transfer and diffusion resistance of H2S molecules, making it easier for gas molecules to reach the ZnO active sites; secondly, the oxygen-containing functional groups of lignin enhance the ZnO's ability to absorb sulfur. 2+ The coordination and anchoring effect of ZnO enables ZnO to be highly dispersed on the carrier surface at the nanoscale, significantly improving the utilization rate of the active component. In contrast, commercial particulate ZnO desulfurizers are limited by mass transfer and diffusion resistance, and the ZnO utilization rate is usually less than 30%.

[0121] Verification Example 2

[0122] This verification example tests the SO2 removal performance of the material obtained in Example 10 at different temperatures and compares it with commercial activated carbon to verify the performance advantages of the material in this application over a wide temperature range.

[0123] The material prepared in Example 10 and commercial coal-based activated carbon (specific surface area 950 m²) were used. 2 10g each of SO2 (saturated SO2 and nitrogen) were packed separately into fixed-bed reactors. A mixture of N2 gas containing 500ppm SO2 was introduced at a space velocity of 1500h⁻¹. -1 The SO2 removal rate was tested at 50℃, 150℃, 250℃ and 350℃ respectively. The desulfurization rate comparison table of the materials in this application and commercial activated carbon at different temperatures is shown in Table 1 below.

[0124] Table 1. Comparison of desulfurization rates of the materials in this application and commercial activated carbon at different temperatures.

[0125]

[0126] This verification example illustrates that activated carbon primarily utilizes physical adsorption, and its adsorption capacity decreases sharply above 150℃ due to weakened van der Waals forces, with a desulfurization rate of only 5% at 350℃. In contrast, the material in this application utilizes chemical adsorption as its primary mechanism. Chemical adsorption is based on chemical reaction bonding, and the reaction rate increases with increasing temperature, maintaining stable and efficient desulfurization performance (>95%) over a wide temperature range of 50–350℃. Simultaneously, the mesoporous structure (5–50 nm) of the semi-coke remains stable at high temperatures, the pores are not easily blocked, and the inorganic oxides loaded on the surface do not decompose significantly below 500℃, collectively ensuring the high-temperature stability of the material.

[0127] Verification Example 3

[0128] This verification example tests the adsorption performance of the material obtained in Example 10 on benzene, verifying the adsorption advantage of its porous structure for volatile organic compounds.

[0129] 1. Take 1g of the material prepared in Example 10 and pack it into a fixed-bed adsorption tube. Introduce a N2 mixture containing 1000ppm benzene at a space velocity of 1000h⁻¹. -1 The adsorption temperature was 25℃. The benzene concentration in the outlet gas was determined by gas chromatography.

[0130] Results: The breakthrough time (outlet benzene concentration > 10 ppm) was 185 min; the dynamic adsorption capacity of benzene was 210 mg / g.

[0131] II. Commercially available coal-based activated carbon (specific surface area 950 m²) is used. 2 Under the same conditions, the dynamic adsorption capacity of benzene was 180 mg / g.

[0132] This verification example illustrates that although the specific surface area of ​​activated carbon (950 m²) 2 / g) is much higher than the material in this application (342m) 2However, the adsorption capacity of the material for benzene in this application (210 mg / g) is superior to that of activated carbon (180 mg / g). This is because the mesopore ratio of the material in this application is greater than 40%, and the mesopore structure has better accessibility and mass transfer efficiency for benzene molecules; at the same time, the aromatic ring structure derived from lignin on the surface of the material undergoes π-π stacking interaction with the benzene ring, and the hydrophobic surface enhances the affinity with hydrophobic benzene molecules, thereby achieving highly efficient adsorption of organic pollutants.

[0133] Verification Example 4

[0134] This verification example tests the adsorption and regeneration performance of the material obtained in Example 10 for tar, verifying the advantages of the mesoporous structure in treating macromolecular pollutants.

[0135] 1. Take 5g of the material prepared in Example 10 and pack it into a fixed-bed reactor. Introduce tar-containing (simulated coke oven flue gas, tar concentration 500mg / m³) gas. 3 A mixture of N2 and air at a space velocity of 500 h⁻¹ -1 The adsorption temperature was 150℃. The system was run continuously, and the amount of tar adsorbed was determined by gravimetric method.

[0136] Results: The tar adsorption capacity was 385 mg / g. After adsorption saturation, thermal regeneration at 350℃ for 3 hours and 5 adsorption-regeneration cycles resulted in an adsorption capacity retention rate of >85%.

[0137] II. Commercially available coal-based activated carbon (specific surface area 950 m²) is used. 2 Under the same conditions, the tar adsorption capacity was 120 mg / g, and due to severe micropore blockage, the capacity decreased rapidly with the increase of regeneration times.

[0138] This verification example illustrates that large molecular tar (with a large molecular dynamic diameter) is prone to pore blockage in the micropores (pore size <2nm) of activated carbon, resulting in low adsorption capacity and difficult regeneration. In contrast, the material of this application is mainly composed of mesopores (5~50nm), which provides ample space and diffusion channels for large molecular tar. Its adsorption capacity is more than 3 times that of activated carbon, and its performance is well restored after thermal regeneration. It is suitable for the purification of tar-containing waste gases such as coke oven flue gas and biomass gasification gas.

[0139] Verification Example 5

[0140] This verification example tests the effect of the material obtained in Example 10 on Pb in wastewater. 2+ Adsorption performance.

[0141] 1. Take 0.5g of the material prepared in Example 10 and add it to 100mL of Pb-containing solution. 2+ In a 100 mg / L lead nitrate solution, the mixture was stirred at 25°C for 2 hours at a stirring speed of 300 rpm. After filtration, the Pb content in the filtrate was determined by atomic absorption spectrometry. 2+concentration.

[0142] Result: Pb 2+ Removal rate 99.3%, adsorption capacity 96 mg / g.

[0143] II. Commercially available coal-based activated carbon (specific surface area 950 m²) is used. 2 / g), tested under the same conditions, Pb 2+ The removal rate was 68.5%, and the adsorption capacity was 34.2 mg / g.

[0144] This verification example illustrates the effect of the application materials on Pb. 2+ The adsorption capacity is approximately 2.8 times that of activated carbon. This is attributed to the synergistic effect of multiple adsorption mechanisms: the porous structure of the material provides physical adsorption sites; the K₂O loaded in the material moderately increases the pH of the solution, promoting the adsorption of Pb. 2+ Hydroxide or carbonate precipitates are formed; oxygen-containing functional groups such as hydroxyl and carboxyl groups on the lignin / semi-coke surface coordinate with Pb. 2+ Stable complexes are formed, enabling efficient chemical fixation of heavy metal ions.

[0145] Verification Example 6

[0146] This verification example tests the material obtained in Example 10 against the highly toxic heavy metal Hg. 2+ Adsorption performance.

[0147] Take 0.5g of the material prepared in Example 10 and add it to 100mL of a solution containing Hg. 2+ The solution was stirred at 25°C for 2 hours in a 50 mg / L mercuric nitrate solution. After filtration, the Hg content in the filtrate was determined by cold atomic absorption spectrometry. 2+ concentration.

[0148] Result: Hg 2+ Removal rate 99.6%, adsorption capacity 49.8 mg / g, effluent Hg 2+ Concentration <0.5μg / L.

[0149] This embodiment illustrates the application materials regarding Hg. 2+ It exhibits excellent removal performance. The oxygen-containing functional groups on the material surface react with Hg. 2+ Complexation coordination occurs, and the ZnO component can simultaneously bind Hg 2+ It is converted into insoluble sulfides or stable compounds, achieving deep removal of highly toxic heavy metals.

[0150] Verification Example 7

[0151] This verification example tests the effect of the material obtained in Example 10 on Cr. 6+ The reduction and fixation properties were verified to enhance the redox function of the carbon matrix on the semi-coke support.

[0152] Take 0.5 g of the material prepared in Example 10 and add it to 100 mL of Cr-containing... 6+ The solution was prepared in a 50 mg / L potassium dichromate solution, pH 3, and stirred at 25°C for 2 hours. After filtration, the Cr content in the filtrate was determined by diphenylcarbazide spectrophotometry. 6+ concentration.

[0153] Result: Cr 6+ Removal rate 96.5%, Cr in the treated solution 3+ The concentration accounts for 93% of the total chromium.

[0154] This verification example demonstrates that the material of this application can not only remove heavy metals through adsorption and complexation, but also utilize the carbon matrix in the semi-coke support to exert a reducing effect, thereby removing highly toxic Cr. 6+ Reduced to low-toxicity Cr 3+ It achieves detoxification and fixation, a unique function that traditional activated carbon and pure ZnO materials do not possess.

[0155] Verification Example 8

[0156] This verification example tests the performance retention of the material obtained in Example 10 after multiple adsorption-regeneration cycles, and verifies the robustness of the active component loading and its anti-sintering properties.

[0157] 10g of the material prepared in Example 10 was packed into a fixed-bed reactor (10mm inner diameter). A N2 mixture containing 100ppm H2S was introduced at a space velocity of 2000h⁻¹. -1 The reaction temperature was 350℃. The H2S concentration in the outlet gas was detected by gas chromatography. After H2S adsorption saturation, air was introduced for regeneration at 500℃ for 2 hours, and the adsorption test was repeated after regeneration. The adsorption-regeneration cycle was repeated 10 times, and the cycle regeneration stability performance parameters are shown in Table 2 below.

[0158] Table 2 Stability Performance Parameters of Cyclic Regeneration

[0159]

[0160] Structural characterization after 10 cycles: Specific surface area retention rate was 83%, ZnO grain size increased from 12nm to 17nm (slight growth), and no obvious sintering occurred.

[0161] This verification example demonstrates that the material of this application exhibits excellent cyclic regeneration stability. Alkali metal oxides and ZnO are firmly loaded onto the carrier surface through chemical bonding and coordination, and are not easily detached during high-temperature regeneration. The mesoporous structure provides a stable dispersion carrier for the active components, and the pore isolation effect effectively inhibits the sintering and agglomeration of the active components. After 10 cycles, the sulfur capacity retention rate is >85%, and the ZnO grains only grow slightly, exhibiting good anti-sintering performance.

[0162] Verification Example 9

[0163] This verification example tests the long-term stability of the material obtained in Example 10 under continuous operating conditions.

[0164] 100g of the material prepared in Example 10 was packed into a fixed-bed reactor. The reactor was heated at 350°C and a space velocity of 2000 h⁻¹. -1 The material was continuously operated for 500 hours under certain conditions, and samples were taken periodically to test its performance. The long-term stability performance parameters of the samples are shown in Table 3 below.

[0165] Table 3. Long-term stability performance parameters of the samples

[0166]

[0167] This validation example demonstrates that after 500 hours of continuous operation, the material's main performance indicators retained >85%, and the H2S penetration time only decreased from 175 min to 162 min (a reduction of approximately 7.4%). This is attributed to the stable chemical bonding between the active component and the support, as well as the dispersion and isolation effect of the mesoporous structure on the active component, enabling the material to maintain good structural integrity and purification activity during long-term operation at high temperatures.

[0168] Verification Example 10

[0169] This verification example tests the stabilization and remediation effect of the material obtained in Example 10 on heavy metal contaminated soil.

[0170] A Pb- and Cd-contaminated soil sample (Pb content 450 mg / kg, Cd content 8.5 mg / kg, pH=5.2) was taken and the material prepared in Example 10 was added at a ratio of 3% of the soil mass. The mixture was thoroughly mixed, kept at a moisture content of 30%, and cured for 28 days, turning it over every 7 days during this period. After the curing period, the leaching concentration of heavy metals was determined using the TCLP method (Toxicity Characteristic Leaching Procedure). The comparison table of heavy metal leaching concentrations is shown in Table 4 below.

[0171] Table 4 Comparison of Heavy Metal Leaching Concentrations

[0172]

[0173] This verification example illustrates that, after the material of this application is mixed with contaminated soil for curing, heavy metal stabilization is achieved through multiple mechanisms: the porous structure of the material adsorbs heavy metal ions from the soil pore water; alkaline substances such as K2O increase the soil pH, promoting the precipitation of heavy metal hydroxides or carbonates; oxygen-containing functional groups on the lignin / semi-coke surface form stable complexes with heavy metal ions; and the Cr... 6+For metals with variable valence, a semi-coke matrix can reduce them to a low-toxicity form. After treatment, the leaching concentration of heavy metals in the soil is significantly reduced, meeting the requirements of the "Identification Standard for Hazardous Waste - Leaching Toxicity Identification" (GB 5085.3-2007), and can be used for industrial land, fill soil, or landscaping soil.

[0174] Comparative Example 1

[0175] This comparative example demonstrates the adverse effects of omitting the flotation separation step on the final product performance, thus verifying the necessity of flotation separation.

[0176] 100 g of the composite carrier powder obtained in Example 8 (without flotation separation, ash content 8.2%) was directly integrally molded and loaded according to the method in Example 10 to obtain the composite purification material of this application, which was used as a comparative sample. The performance comparison table is shown in Table 5 below.

[0177] Table 5 Performance Comparison Table

[0178]

[0179] This comparative example illustrates that omitting the flotation separation step leads to an increase in the ash content of the final product to 7.8%. High ash content not only dilutes the effective content of the active component and the carrier but also disrupts the bonding continuity between carrier particles, resulting in a decrease in lateral compressive strength (from 95N to 78N) and an increase in abrasion rate (from 1.5% to 2.4%). After flotation separation, the ash content is reduced to 1.5%, and the mechanical strength is significantly improved, verifying the necessity and technical effectiveness of the simultaneous alkaline impregnation and flotation separation process.

[0180] Comparative Example 2

[0181] This comparative example demonstrates the difference in the impact of pure semi-coke carriers and lignin-semi-coke composite carriers on the performance of the final product, and verifies the triple function of lignin.

[0182] 100 g of pure semi-coke carrier (prepared by conventional pyrolysis method without lignin) was taken and the composite purification material of this application was prepared as a comparative sample according to the specific methods described in Examples 9 and 10. The performance comparison table is shown in Table 6 below.

[0183] Table 6 Performance Comparison Table

[0184]

[0185] This comparative example illustrates that the pure semi-coke carrier lacks the alkali-soluble activation products of lignin to provide adhesion during alkaline impregnation. Its formation relies on the physical interlocking of powder particles, resulting in a lateral compressive strength of only 72 N and an abrasion rate of 2.3%. In contrast, the lignin-semi-coke composite carrier, after being dissolved and activated in alkaline solution, functions as a natural binder. Upon calcination, it carbonizes into an amorphous carbon skeleton, forming a chemically bonded continuous phase with the semi-coke, significantly improving the material's mechanical strength (lateral compressive strength increased by 32%, abrasion rate reduced by 35%). Furthermore, the lignin originates from industrial wastes such as biomass hydrolysis residue and papermaking black liquor, resulting in extremely low raw material costs and achieving synergistic effects of waste resource utilization and material performance improvement. The pure semi-coke carrier also exhibits weaker dispersion ability for active components (due to the lack of oxygen-containing functional group coordination anchors provided by lignin), leading to a slightly lower H2S penetration time and SO2 removal rate compared to the lignin-semi-coke composite carrier provided in this application.

[0186] In summary, this application provides a supported lignin-semi-coke composite multifunctional purification material, its preparation method, and its application. This material is a composite carrier prepared by co-pyrolysis of coal and lignin, loaded with K2O / Na2O and ZnO active components at a loading of 5%–20%. During preparation, the composite carrier powder is added to an alkaline solution, heated and stirred, utilizing density differences to simultaneously achieve flotation separation (removal of inorganic impurities), lignin activation, and alkali metal loading. The upper effective components are collected, zinc acetate is added, and the mixture is kneaded and shaped. A single calcination completes zinc salt decomposition and lignin carbonization. Lignin simultaneously acts as a binder, carbon skeleton reinforcement, and active component dispersant, eliminating the need for additional binders. The calcination decomposition products of zinc acetate are only ZnO, CO2, and H2O, making it environmentally friendly. This material exhibits high efficiency in removing gases such as H2S, SO2, and HCl, with a benzene dynamic adsorption capacity of 210 mg / g, a tar adsorption capacity of 385 mg / g, and a Pb adsorption capacity of [missing information]. 2+ Cd 2+ Hg 2+ The adsorption capacity for heavy metal ions is 2-5 times that of activated carbon. It exhibits stable performance over a wide temperature range of 150-700°C, with mechanical strength 20%-30% higher than pure semi-coke. After 10 regeneration cycles, the capacity retention rate is >85%, and after 500 hours of continuous operation, the main performance retention rate is >85%. When used for soil remediation, it can convert migratory heavy metals into stable states, ensuring the treated soil meets standards for industrial land, fill soil, or landscaping soil. Furthermore, this application achieves synergy between waste resource utilization and the preparation of high-performance purification materials, possessing advantages such as high process integration, low cost, superior performance, wide temperature range adaptability, long-term stability, and environmental friendliness, demonstrating promising industrialization prospects.

[0187] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

[0188] The present application has been described in a relatively specific and detailed manner above through general descriptions and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the protection scope of the claims of the present application.

Claims

1. A supported lignin-semi-coke composite multifunctional purification material, characterized in that, include: A lignin-semi-coke composite carrier is prepared by co-pyrolysis of coal and lignin, wherein the amount of lignin added is 5% to 20% of the coal mass, and the surface of the lignin-semi-coke composite carrier has oxygen-containing functional groups. In addition, the active components loaded on the surface of the lignin-semi-coke composite carrier, wherein the oxygen-containing functional groups are used to promote the uniform dispersion of the active components on the carrier surface, and the active components include alkali metal oxides and zinc oxide, and the loading of the active components is 5% to 20% based on the total mass of the material.

2. The supported lignin-semi-coke composite multifunctional purification material according to claim 1, characterized in that, The lignin-semi-coke composite carrier is a homogeneous structure formed by chemical bonding of lignin carbon and semi-coke. The lateral compressive strength of the lignin-semi-coke composite carrier is 20% to 30% higher than that of the pure semi-coke carrier. The specific surface area of the lignin-semi-coke composite carrier is 200-500 m 2 / g, and the pore volume is 0.2-0.6 cm 3 / g, the mesopore ratio is greater than 40%, and the mesopore diameter ranges from 5 nm to 50 nm.

3. The supported lignin-semi-coke composite multifunctional purification material according to claim 1, characterized in that, The oxygen-containing functional group includes one or more of hydroxyl, carboxyl, and carbonyl groups; The alkali metal oxide is K2O or Na2O; The lignin is derived from one or more of the following: biomass hydrolysis residue, papermaking black liquor, and enzymatically hydrolyzed lignin.

4. A method for preparing a supported lignin-semi-coke composite multifunctional purification material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Add lignin-semi-coke composite carrier powder to an alkali metal hydroxide solution, heat to 80~95℃, stir for 30~60 minutes to dissolve and activate lignin in the alkali solution, and load alkali metal ions onto the carrier surface; Flotation separation is performed using density differences to collect the effective components in the upper layer; S2: Add zinc acetate solution to the upper effective component, stir and knead to form a soft material, and then granulate it. S3: After drying, calcination is carried out at 300~500℃ in an inert atmosphere for 1~4 hours to obtain the molded purification material; The lignin can serve as a binder, a carbon skeleton reinforcement, and an active component dispersant. The phenolic hydroxyl and carboxyl groups provided by the lignin coordinate with the metal ions in the alkali metal hydroxide solution, promoting the uniform dispersion of the active component on the carrier surface.

5. The preparation method of the supported lignin-semi-coke composite multifunctional purification material according to claim 4, characterized in that, In step S1, the alkali metal hydroxide solution is KOH or NaOH, with a concentration of 0.5~2.0 mol / L; In step S1, the flotation separation using density difference specifically includes: a lightweight lignin-semi-coke composite carrier is suspended or floated on the upper layer of the liquid phase, while dense inorganic impurities settle to the bottom of the liquid phase, and the effective components in the upper layer are collected by overflow or retrieval. In step S2, the concentration of the zinc acetate solution is 0.5~1.5 mol / L; In step S2, granulation is carried out by ball rolling granulation or extrusion granulation to control the particle size to 1~5mm; In step S3, the inert atmosphere is a nitrogen or argon atmosphere; during the calcination process, alkali metal hydroxides are converted into alkali metal oxides, zinc acetate is decomposed into ZnO, and lignin is carbonized into an amorphous carbon skeleton.

6. A method for preparing a lignin-semi-coke composite carrier, wherein the lignin-semi-coke composite carrier is used in the preparation method of the supported lignin-semi-coke composite multifunctional purification material according to any one of claims 4 to 5, characterized in that, Includes the following steps: Coal powder and lignin powder are mixed and subjected to supercritical carbon dioxide dynamic cyclic pyrolysis at 280~320℃ and 8~20MPa to carbonize lignin and coal simultaneously, forming a lignin-semi-coke composite carrier; the amount of lignin added is 5%~20% of the coal mass.

7. The method for preparing the lignin-semi-coke composite carrier according to claim 6, characterized in that, The reaction time for the supercritical carbon dioxide dynamic cyclic pyrolysis is 1 to 4 hours. In the supercritical carbon dioxide dynamic cyclic pyrolysis process, a co-solvent is also added, and the amount of the co-solvent added is 2% of the coal powder mass. The lignin is derived from one or more of the following: biomass hydrolysis residue, papermaking black liquor, and enzymatically hydrolyzed lignin.

8. A lignin-semi-char composite carrier, characterized in that, The lignin-semi-coke composite carrier is prepared by the preparation method of any one of claims 6 or 7, wherein the lignin-semi-coke composite carrier is formed by chemical bonding of lignin carbon and semi-coke to form a homogeneous structure, and the surface of the lignin-semi-coke composite carrier has oxygen-containing functional groups. The lateral compressive strength of the lignin-semi-coke composite carrier is 20% to 30% higher than that of the pure semi-coke carrier; the specific surface area of ​​the lignin-semi-coke composite carrier is 200 to 500 m². 2 / g, pore volume 0.2~0.6cm 3 / g, with a mesopore ratio greater than 40% and a mesopore diameter range of 5~50nm; The oxygen-containing functional group includes at least one of hydroxyl, carboxyl, and carbonyl groups.

9. The application of the supported lignin-semi-coke composite multifunctional purification material according to any one of claims 1 to 3 in gas purification.

10. The application of the supported lignin-semi-coke composite multifunctional purification material according to claim 9 in gas purification, characterized in that, The gases to be treated include one or more of the following: H2S, SO2, HCl, CO2, volatile organic compounds, and light tar. The volatile organic compounds include one or more of benzene, toluene, and xylene; The steps for purifying gas using the aforementioned supported lignin-semi-coke composite multifunctional purification material include: loading the composite multifunctional purification material into a fixed-bed or fluidized-bed reactor, with a gas space velocity of 500~5000 h⁻¹. -1 The processing temperature is 25℃~700℃.

11. The application of the supported lignin-semi-coke composite multifunctional purification material according to any one of claims 1 to 3 in wastewater treatment or soil remediation.

12. The application of the supported lignin-semi-coke composite multifunctional purification material according to claim 11 in wastewater treatment or soil remediation, characterized in that, The wastewater and soil to be treated each contain heavy metal ions, including Pb. 2+ Cd 2+ Cu 2+ Ni 2+ Zn 2+ Hg 2+ As 3+ Cr 6+ One or more of the following; The steps for treating the wastewater using the supported lignin-semi-coke composite multifunctional purification material include: adding the composite multifunctional purification material into the wastewater to be treated, with a solid-liquid ratio of 1:10 to 1:100, stirring for 0.5 to 3 hours at a stirring speed of 100 to 500 rpm, and a treatment temperature of 10°C to 80°C. The composite multifunctional purification material forms stable complexes with heavy metal ions through its oxygen-containing functional groups, thereby achieving complexation and stabilization of heavy metal ions. The steps for treating and remediating the soil to be treated using the aforementioned loaded lignin-semi-coke composite multifunctional purification material include: mixing the composite multifunctional purification material with heavy metal contaminated soil at a mixing ratio of 1% to 5%, maintaining the soil moisture content at 20% to 40%, and curing for 7 to 30 days, during which the mixture is turned over regularly.

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