Coal-based sorbents, methods of making and using the same

Abstract

The application discloses a coal-based adsorbent and a preparation method and application thereof, and the coal-based adsorbent comprises a porous coal-based carrier and a metal chloride salt loaded on the porous coal-based carrier. The single extraction efficiency of the adsorbent for extracting phenolic compounds in coal tar can reach more than 90%. Compared with the prior art, the adsorbent has the advantages of simple process, stable operation, green environmental protection and the like. When the adsorbent is used for separating phenolic compounds in coal tar, no secondary pollution of phenol-containing wastewater is caused, the adsorbent and a regeneration solvent can be recycled, one-time investment and operation cost are low, and the adsorbent is a clean technology for separating phenols in coal tar.

Description

Technical Field

[0001] This invention relates to the fields of coal chemical and petrochemical separation technology, and in particular to a coal-based adsorbent, its preparation method, and its application. Background Technology

[0002] Coal tar contains a large number of high-value-added chemicals, among which phenolic compounds are the most typical and are one of the most widely used and important industrial organic chemicals. Traditional hydrogenation processes significantly reduce the value of coal tar. Traditional phenolic compound separation processes rely on the neutralization reaction of phenolic compounds with NaOH aqueous solution to form sodium phenolate, which is then transferred from the coal tar to the aqueous solution. The sodium phenolate solution is then acidified with sulfuric acid, and solvent extraction is used to recover the phenolic substances. This treatment method is complex, generates large amounts of acidic and alkaline wastewater, is costly, and causes significant environmental pollution, severely restricting the development of the industry extracting high-value-added chemicals from coal tar. Furthermore, the large amount of phenol-containing wastewater generated is one of the most difficult industrial wastewaters to biodegrade and treat.

[0003] CN103420802A discloses a method for separating phenolic compounds from oil, using imidazole ionic liquids as separating agents. The ionic liquid combines with phenolic compounds to form an ionic liquid phase, thereby achieving oil-phenol separation. During the separation process, ether-based back-extraction ionic liquids are used to separate phenols and ionic liquids, or inert gas stripping is employed to separate phenols and ionic liquids. Although this method has high extraction efficiency for phenolic compounds, the ionic liquids are expensive, and there are no industrial applications. CN106588579A discloses a method for extracting phenolic compounds from phenol-containing oil, using a mixture of ethylenediamine and ethanolamine as the extractant in a 1:1 mass ratio. The extractant is used to contact the phenol-containing oil countercurrently in an extraction tower. The extracted phase flows out from the bottom of the tower, and the extractant is separated by distillation under normal pressure. The raffinate is separated by washing with water and distillation to remove the extractant, and then returned to the extraction tower for reuse. This method has high extraction efficiency, but these solvents are oil-soluble, which not only contaminates the tar but also complicates the separation process. CN112391186A discloses a method for separating phenolic compounds from coal tar. The method involves extracting phenols from coal tar using a halogen quaternary ammonium salt extractant, preferably a chloride salt. After separating the oil phase, ethyl acetate is used as the back-extraction agent to back-extract the extract phase, achieving an extraction efficiency of 88%–93%. However, the organic salts used in this method readily adsorb moisture, and the Cl- in the aqueous solution… - It has a strong corrosive effect on steel equipment.

[0004] In summary, current industrial-scale acid-base methods suffer from high pollution and high costs for treating phenol-containing wastewater, necessitating the development of clean phenol extraction technologies. Existing environmentally friendly phenol extraction technologies still face challenges such as high costs, complex processes, and equipment corrosion. Therefore, there is a need to develop a non-corrosive, physically stable, environmentally friendly, highly efficient, and low-cost phenol extraction technology.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] This invention utilizes the Lewis acid-base reaction between metal chloride salts and phenol to adsorb phenolic substances from coal tar, and then uses solvent elution to extract the phenolic substances, thus solving the problems of pollution and complex processes in the current phenol extraction process.

[0007] One of the objectives of this invention is to provide a coal-based adsorbent.

[0008] The second objective of this invention is to provide a method for preparing the coal-based adsorbent.

[0009] The third objective of this invention is to provide an application of this coal-based adsorbent in the extraction of phenolic compounds from coal tar.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0011] In a first aspect, the present invention provides a coal-based adsorbent, comprising: a porous coal-based support, which is prepared by molding and calcining coal powder; and a metal chloride salt loaded on the porous coal-based support;

[0012] Preferably, the loading of metal chloride salt is 0.02-0.2% based on the weight of the coal-based adsorbent.

[0013] The pulverized coal can be any coking coal known in the art, including but not limited to coking coal, lean coal, fat coal, and gas coal, preferably coking coal and lean coal, with the mass ratio of lean coal to coking coal preferably being 0.1-10:1.

[0014] The metal chloride salt can be any inorganic metal chloride salt known in the art, including but not limited to aluminum chloride, zinc chloride, stannous chloride, etc.

[0015] In some embodiments, the preparation of porous coal-based supports includes the following steps:

[0016] Coal powder, pore-forming agent and binder are mixed, kneaded and aged, then shaped, heated and roasted, then ground, impurities removed, washed and dried to obtain a porous coal-based carrier.

[0017] Pore-forming agents can be additives known in the art that create porous structures in materials, including but not limited to polyvinyl butyral, polymethyl methacrylate, etc.

[0018] The binder can be any known additives for bonding and molding, including but not limited to sodium carboxymethyl cellulose, corn starch, nitrocellulose, cellulose acetate, etc.

[0019] Preferably, the mass ratio of pore-forming agent to binder is 1-5:1, and the mass ratio of coal powder to the mixture of pore-forming agent and binder is 1-30:1.

[0020] Preferably, the calcination temperature is 600-1500℃, the heating rate is 1-8℃ / min, the calcination time is 60-90min, and the calcination atmosphere is an inert atmosphere.

[0021] Preferably, the impurity removal includes: removing metallic impurities with hydrochloric acid aqueous solution and removing silicon with hydrofluoric acid aqueous solution;

[0022] Preferably, the concentration of the hydrochloric acid aqueous solution is 1-6 mol / L, the stirring temperature during removal is 50-100℃, the stirring time is 12-48h, and the stirring rate is 100-1000 rpm.

[0023] Preferably, the concentration of the hydrofluoric acid aqueous solution is 10-20%, the stirring temperature during removal is 50-100℃, the stirring time is 12-48h, and the stirring rate is 100-1000rpm.

[0024] Preferably, the drying temperature is 100-130℃ and the drying time is 6-24h.

[0025] In some specific embodiments, the preparation of porous coal-based supports includes the following steps:

[0026] Mix and grind coking coal and lean coal in a mass ratio of 1:0.1-10 to obtain mixture A;

[0027] The pore-forming agent polyvinyl butyral and the binder sodium carboxymethyl cellulose are added to mixture A at a mass ratio of 1-5:1, and the mass ratio of coal powder to the mixture of pore-forming agent and binder is 1-30:1 to obtain mixture B.

[0028] Mixture B is kneaded in a vacuum pumice machine and then aged. It is then extruded and shaped by a molding device and dried at room temperature to obtain substance C.

[0029] Substance C is heated from room temperature to 600-1500℃ in N2 atmosphere at a heating rate of 1-8℃ / min and held at that temperature for 60-90min. Then it is cooled to room temperature to obtain coal-based material, which is crushed, ground, and passed through a 400-mesh sieve to obtain substance D.

[0030] Add substance D to a 1-6 mol / L hydrochloric acid aqueous solution, stir at 50-100℃ for 12-48 h to remove metal impurities, separate the residual liquid to obtain substance E;

[0031] Then, substance E is taken out and added to an excess of 10-20% hydrofluoric acid aqueous solution, and stirred at 50-100℃ for 12-48h to remove the Si contained in substance E, to obtain substance F;

[0032] Finally, substance F was washed with deionized water until the washing solution was neutral. The resulting coal-based carbon powder was ultrasonically cleaned with ethanol and then dried at 100-130℃ for 6-24 hours to obtain porous coal-based carrier G.

[0033] Secondly, the present invention provides a method for preparing the above-mentioned coal-based adsorbent, comprising the following steps:

[0034] (1) Providing a porous coal-based carrier: Coal powder, pore-forming agent and binder are mixed, kneaded and aged, then shaped, then heated and roasted, then ground, impurities removed, washed and dried to obtain a porous coal-based carrier.

[0035] (2) Metal chloride salts are loaded onto a porous coal-based carrier by impregnation to obtain a coal-based adsorbent.

[0036] The following is a detailed explanation of each step:

[0037] Step (1)

[0038] The pulverized coal can be any coking coal known in the art, including but not limited to coking coal, lean coal, fat coal, and gas coal, preferably coking coal and lean coal. The mass ratio of lean coal to coking coal is preferably 0.1-10:1, such as 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc., but not limited thereto.

[0039] Pore-forming agents can be additives known in the art that create porous structures in materials, including but not limited to polyvinyl butyral, polymethyl methacrylate, etc.

[0040] The binder can be any known additives for bonding and molding, including but not limited to sodium carboxymethyl cellulose, corn starch, nitrocellulose, cellulose acetate, etc.

[0041] Preferably, the mass ratio of pore-forming agent to binder is 1-5:1, such as 1:1, 2:1, 3:1, 4:1, 5:1, etc., but not limited thereto; the mass ratio of coal powder to the mixture of pore-forming agent and binder is 1-30:1, such as 1:1, 2:1, 5:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1, 25:1, etc., but not limited thereto.

[0042] Preferably, the calcination temperature is 600-1500℃, the heating rate is 1-8℃ / min, the calcination isothermal time is 60-90min, and the calcination atmosphere is an inert atmosphere.

[0043] Preferably, the impurity removal includes: removing metallic impurities with hydrochloric acid aqueous solution and removing silicon with hydrofluoric acid aqueous solution;

[0044] Preferably, the concentration of the hydrochloric acid aqueous solution is 1-6 mol / L, the stirring temperature during removal is 50-100℃, the stirring time is 12-48h, and the stirring rate is 100-1000 rpm.

[0045] Preferably, the concentration of the hydrofluoric acid aqueous solution is 10-20%, the stirring temperature during removal is 50-100℃, the stirring time is 12-48h, and the stirring rate is 100-1000rpm.

[0046] Preferably, the drying temperature is 100-130℃ and the drying time is 6-24h.

[0047] Step (2)

[0048] The metal chloride salt can be any inorganic metal chloride salt known in the art, including but not limited to aluminum chloride, zinc chloride, stannous chloride, etc.

[0049] Step (2) includes: the porous coal-based carrier and the anhydrous ethanol solution of the metal chloride salt are continuously heated and refluxed under nitrogen protection and stirring, naturally cooled to room temperature, and then filtered, washed, dried and solidified to obtain the coal-based adsorbent.

[0050] Preferably, the concentration of the metal chloride salt in the anhydrous ethanol solution is 10-150 g / L;

[0051] The mass ratio of porous coal-based carrier to metal chloride salt is 0.5-1:0.02-0.2, preferably 0.5:0.1.

[0052] Preferably, the reflux temperature is 50-100°C;

[0053] Preferably, the drying temperature is 100-130℃ and the drying time is 5-10 hours;

[0054] Preferably, the curing temperature is 100-150℃, the curing time is 1-5h, and the curing is carried out under an inert atmosphere.

[0055] In some specific embodiments, the preparation method of coal-based adsorbents includes the following steps:

[0056] The preparation of porous coal-based supports includes the following steps:

[0057] Mix and grind coking coal and lean coal in a mass ratio of 1:0.1-10 to obtain mixture A;

[0058] The pore-forming agent polyvinyl butyral and the binder sodium carboxymethyl cellulose are added to mixture A at a mass ratio of 1-5:1, and the mass ratio of coal powder to the mixture of pore-forming agent and binder is 1-30:1 to obtain mixture B.

[0059] Mixture B is kneaded in a vacuum pumice machine and then aged. It is then extruded and shaped by a molding device and dried at room temperature to obtain substance C.

[0060] Substance C is heated from room temperature to 600-1500℃ in N2 atmosphere at a heating rate of 1-8℃ / min and held at that temperature for 60-90min. Then it is cooled to room temperature to obtain coal-based material, which is crushed, ground, and passed through a 400-mesh sieve to obtain substance D.

[0061] Add substance D to a 1-6 mol / L hydrochloric acid aqueous solution, stir at 50-100℃ for 12-48 h to remove metal impurities, separate the residual liquid to obtain substance E;

[0062] Then, substance E is taken out and added to an excess of 10-20% hydrofluoric acid aqueous solution, and stirred at 50-100℃ for 12-48h to remove the Si contained in substance E, to obtain substance F;

[0063] Finally, substance F was washed with deionized water until the washing solution was neutral. The obtained coal-based carbon powder was ultrasonically cleaned with ethanol and then dried at 100-130℃ for 6-24 hours to obtain porous coal-based carrier G.

[0064] The preparation of coal-based adsorbent includes the following steps: Substance G and an anhydrous ethanol solution of a metal chloride salt are sequentially added to a reaction vessel. The concentration of the metal chloride salt is 10-150 g / L, and the mass ratio of the porous coal-based carrier to the metal chloride salt is 0.5-1:0.02-0.2. Under nitrogen protection and stirring, the mixture is continuously heated to reflux at 50-100℃ and naturally cooled to room temperature to obtain substance H. Substance H is filtered, washed with ethanol, and dried at 100-130℃ for 5-10 h. Then, it is placed in a crucible and placed in a controllable box-type resistance furnace and cured at 100-150℃ for 1-5 h under N2 atmosphere to finally obtain the coal-based adsorbent material.

[0065] Thirdly, the present invention provides an application of the above-mentioned coal-based adsorbent in the extraction of phenolic compounds from coal tar.

[0066] In some embodiments, the application includes: mixing coal tar and the coal-based adsorbent for adsorption;

[0067] Preferably, the mass ratio of coal-based adsorbent to coal tar is 0.5-5:1, such as 1:1, 2:1, 3:1, 4:1, 5:1, etc., but not limited thereto;

[0068] Preferably, the adsorption temperature is 10-80℃, the adsorption time is 1-3h, and the adsorption is carried out by mechanical stirring or magnetic stirring at a stirring rate of 100-1000rpm.

[0069] In some embodiments, the application further includes: eluting the adsorbed coal-based adsorbent with an organic solvent, filtering and collecting the eluent, distilling off the phenol, and reusing the separated organic solvent; and drying the solid phase for reuse.

[0070] Preferably, the organic solvent is at least one selected from diethyl ether, ethyl acetate, and dichloromethane;

[0071] Preferably, the elution time is 10-30 min, and mechanical stirring is used at a stirring speed of 100-1000 rpm;

[0072] Preferably, the distillation temperature is 30-100℃;

[0073] Preferably, the drying temperature is 30-100℃, and the drying time is 2-5 hours;

[0074] In some specific embodiments, the application includes: placing coal tar in a flask, then adding an adsorbent to the flask at a temperature of 10-80°C, with a mass ratio of coal-based adsorbent to coal tar of 0.5-5:1, and rapidly stirring at 100-1000 rpm. After adsorption for 1-3 hours, the reaction product is filtered, and then the adsorbent saturated with phenol is eluted with an organic solvent in a flask, with stirring at 100-1000 rpm for 10-30 minutes. The eluent is filtered, collected, and the phenol is distilled off at 30-100°C. The separated organic solvent is reused. The solid phase is dried at 30-100°C for 2-5 hours and then reused.

[0075] Beneficial effects

[0076] This invention uses coal as raw material to prepare a coal-based adsorbent carrier. The coal-based carrier is then used to prepare a coal-based adsorbent carbon material through impregnation and loading of metal chloride salts. This adsorbent is then used to adsorb phenolic compounds from coal tar, achieving a single-pass extraction efficiency of over 90%. Compared with existing technologies, this method offers advantages such as simple process, stable operation, and environmental friendliness. Using this adsorbent to separate phenolic compounds from coal tar does not generate secondary pollution from phenol-containing wastewater. Both the adsorbent and the regeneration solvent can be recycled, resulting in low initial investment and operating costs. This is a clean technology for separating phenols from coal tar.

[0077] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments.

[0078] Unless otherwise expressly stated, numerical ranges throughout the application include any subranges therein and any numerical values ​​incremented by the smallest subunit of a given value. Unless otherwise expressly stated, numerical values ​​throughout the application represent approximate measures or limitations on the range of embodiments including minor deviations from a given value and having approximately the mentioned value as well as having the mentioned precise value. Except in the detailed description of the working embodiments provided at the end, all numerical values ​​of parameters (e.g., quantities or conditions) in this application (including the appended claims) should in all cases be understood to be modified by the term “approximately,” regardless of whether “approximately” actually precedes the numerical value. “Approximately” indicates that the stated numerical value allows for slight inaccuracies (some close to precision at that value; approximately or reasonably close to the value; approximate). If the inaccuracy provided by “approximately” is not understood in this common sense in the art, then “approximately” as used herein at least indicates a variation that can be produced by common methods of measuring and using these parameters. For example, “approximately” can include variations less than or equal to 10%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, less than or equal to 1%, or less than or equal to 0.5%. Detailed Implementation

[0079] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0080] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0081] The coking coal and lean coal came from a mine in Shanxi.

[0082] Example 1

[0083] Preparation of the adsorbent carrier: Coking coal and lean coal were ground into powder. Then, 10g of coking coal powder, 30g of lean coal powder, 2g of polyvinyl butyral, and 1g of sodium carboxymethyl cellulose were mixed, pounded and aged in a vacuum slurry machine, and then extruded into shape using an extrusion molding device. The mixture was then naturally dried at room temperature to obtain coal-based strip materials. Subsequently, the obtained coal-based strip materials were heated from room temperature to 950℃ at a heating rate of 3℃ / min under a N2 atmosphere, and held at 950℃ for 60min, followed by natural cooling to room temperature. The cooled coal-based strip materials were ground to 400 mesh and added to a 6mol / L hydrochloric acid aqueous solution. The mixture was stirred at 60℃ for 24h at a stirring rate of 220rpm. Then, carbon powder was removed and added to an excess of 10% hydrofluoric acid aqueous solution, and stirred at 60℃ for 24h at a stirring rate of 220rpm. Finally, the toner was filtered and washed with deionized water until the filtrate was neutral. After ultrasonic cleaning with ethanol, it was dried at 120°C for 12 hours to obtain the finished coal-based toner carrier.

[0084] Adsorbent preparation: 250g of carrier and 1L of anhydrous aluminum chloride ethanol solution were added sequentially to a reaction vessel. The concentration of aluminum chloride was 50g / L. The mixture was continuously heated under nitrogen protection and stirring at approximately 78℃ and refluxed for 4h. After natural cooling to room temperature, the sample was filtered, washed with ethanol, and dried at 120℃ for 6h. Then, it was placed in a crucible and cured in a controlled box-type resistance furnace under N2 atmosphere for 4h at a curing temperature of 140℃ to obtain the prepared coal-based adsorbent with an aluminum chloride loading of 0.07g / g adsorbent.

[0085] A simulation experiment was conducted in a 250L flask:

[0086] Extraction efficiency of total phenols (%) = (Total phenol content in raw coal tar - Total phenol content in coal tar after extraction) / Total phenol content in raw coal tar. The determination of total phenols shall be performed in accordance with GB / T-38397-2019.

[0087] Adsorption experiment: 20g of coal tar (from Xuyang Coking Plant, distillation temperature 170℃~230℃) was added to a flask. Then, 30g of adsorbent was added to the flask at 40℃, and mechanically stirred for 1.5h at a stirring rate of 400rpm. After adsorption, the oil layer was removed from the flask. The adsorbent that had adsorbed phenols was then washed three times with diethyl ether. Each wash was performed with stirring for 15min at room temperature at a stirring rate of 220rpm. The ether phase was collected at room temperature and distilled at 40℃. The solid phase was dried at 40℃ for 2h and reused. The extraction efficiency of total phenols from coal tar was determined to be 95.51%, and the purity of the recovered diethyl ether was 89.75%. After five adsorption-regeneration experiments, the above adsorbent achieved an extraction efficiency of 92.37% for total phenols from coal tar.

[0088] Example 2

[0089] Using the coal-based adsorbent prepared in Example 1, 15 g of adsorbent and 10 g of coal tar were added to a flask at 35°C, and the mixture was mechanically stirred for 1.2 h at a stirring rate of 400 rpm. The extraction efficiency of total phenols from the coal tar was determined to be 91.28%.

[0090] Example 3

[0091] Adsorbent preparation: The adsorbent was prepared according to the adsorbent preparation method in Example 1. Its active component was zinc chloride, its ethanol solution concentration was 70 g / L, and the zinc chloride loading was 0.09 g / g adsorbent.

[0092] Adsorption experiment: 20g of coal tar (from Xuyang Coking Plant, distillation fraction 170℃~210℃) was added to a flask. Then, 25g of adsorbent was added to the flask at 50℃, and mechanically stirred for 1.2h at a stirring rate of 400rpm. After adsorption, the oil layer was removed from the flask. The adsorbent after phenol adsorption was washed three times with ethyl acetate. Each wash was performed with stirring for 15min at room temperature at a stirring rate of 220rpm. The organic phase was collected at room temperature and distilled at 80℃. The solid phase was dried at 80℃ for 2h and reused. The extraction efficiency of total phenols from coal tar was determined to be 93.85%, and the purity of the recovered ethyl acetate was 91.28%. After five adsorption-regeneration experiments, the above adsorbent achieved an extraction efficiency of 90.78% for total phenols from coal tar.

[0093] Example 4

[0094] Using the coal-based adsorbent prepared in Example 3, 15g of adsorbent and 20g of coal tar were added to a flask at 45°C, and the mixture was mechanically stirred for 1.2 hours at a stirring rate of 400 rpm. The extraction efficiency of total phenols from the coal tar was determined to be 89.45%.

[0095] Example 5

[0096] Adsorbent preparation: The adsorbent was prepared according to the adsorbent preparation method in Example 1. Its active component was stannous chloride, its ethanol solution concentration was 100 g / L, and the stannous chloride loading was 0.08 g / g adsorbent.

[0097] Adsorption experiment: 20g of coal tar (from Xuyang Coking Plant, distillation fraction 160℃~220℃) was added to a flask. Then, 30g of adsorbent was added to the flask at 45℃, and mechanically stirred for 2 hours at a stirring rate of 400 rpm. After adsorption, the oil layer was removed from the flask. The adsorbent that had adsorbed phenols was then washed three times with dichloromethane. Each wash was performed with stirring at room temperature for 15 minutes at a stirring rate of 220 rpm. The organic phase was collected at room temperature and distilled at 45℃. The solid phase was dried at 45℃ for 2 hours and reused. The extraction efficiency of total phenols from coal tar was determined to be 94.76%. After five adsorption-regeneration experiments, the extraction efficiency of total phenols from coal tar using the same adsorbent was 91.49%.

[0098] Example 6

[0099] Using the coal-based adsorbent prepared in Example 5, 20g of adsorbent and 20g of coal tar were added to a flask at 35°C, and the mixture was mechanically stirred for 1.5 hours at a stirring rate of 400 rpm. The extraction efficiency of total phenols from the coal tar was determined to be 88.47%.

[0100] Comparative Experiment 1

[0101] The following two sets of adsorption tests were conducted:

[0102] 1. Add 20g of coal tar (from Xuyang Coking Plant, distillation range 170℃~230℃) to a flask. Then, at 40℃, add 28g of the coal-based carbon powder carrier from Example 1 to the flask and mechanically stir for 1.5h at a stirring rate of 400rpm. After adsorption, remove the oil layer from the flask. The extraction efficiency of total phenols from the coal tar was determined to be 47.58%.

[0103] 2. Add 20g of coal tar (from Xuyang Coking Plant, distillation range 170℃~230℃) to a flask. Then, at 40℃, add 2g of aluminum chloride powder to the flask and mechanically stir for 1.5h at a stirring speed of 400rpm. After adsorption, remove the oil layer from the flask. The extraction efficiency of total phenols from the coal tar was determined to be 35.76%.

[0104] The combined extraction efficiency of the two groups was 83.34%.

[0105] The results show that the combined adsorption capacity of using coal-based carrier alone and using aluminum chloride alone is less than the adsorption capacity of the coal-based carrier-aluminum chloride combination in this application, proving that there is a synergistic effect between the coal-based carrier and aluminum chloride combination in this application.

[0106] Comparative Experiment 2

[0107] In this comparative experiment, the coal-based carbon powder carrier in Example 1 was replaced with commercially available activated carbon (from an activated carbon factory in Hebei Province) to obtain an adsorbent. Adsorption tests were conducted according to Example 1, and the extraction efficiency of total phenols in coal tar was determined to be 81.64%.

[0108] It is evident that coal-based carriers offer better extraction performance.

[0109] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. The application of a coal-based adsorbent in the extraction of phenolic compounds from coal tar, characterized in that, The coal-based adsorbent includes: Porous coal-based carriers; and Metal chloride salts, which are supported on porous coal-based carriers; The preparation of the porous coal-based support includes the following steps: Mix and grind coking coal and lean coal at a mass ratio of 1:0.1-10 to obtain mixture A; The pore-forming agent polyvinyl butyral and the binder sodium carboxymethyl cellulose are added to mixture A at a mass ratio of 1-5:1, and the mass ratio of coal powder to the mixture of pore-forming agent and binder is 1-30:1 to obtain mixture B. Mixture B is kneaded in a vacuum pumice machine and then aged. It is then extruded and shaped by a molding device and dried at room temperature to obtain substance C. Substance C was heated from room temperature to 600-1500 ℃ in N2 atmosphere at a heating rate of 1-8 ℃ / min and held at that temperature for 60-90 min. Then it was cooled to room temperature to obtain coal-based material, which was crushed, ground, and passed through a 400-mesh sieve to obtain substance D. Substance D was added to a 1-6 mol / L hydrochloric acid aqueous solution and stirred at 50-100 °C for 12-48 h to remove metal impurities. The residual liquid was then separated to obtain substance E. Then, substance E is taken out and added to an excess of 10-20% hydrofluoric acid aqueous solution, and stirred at 50-100 °C for 12-48 h to remove the Si contained in substance E, so as to obtain substance F; Finally, substance F was washed with deionized water until the washing solution was neutral. The resulting coal-based carbon powder was ultrasonically cleaned with ethanol and then dried at 100-130 °C for 6-24 h to obtain porous coal-based carrier G.

2. The application according to claim 1, characterized in that, Based on the weight of the coal-based adsorbent, the loading of metal chloride salts is 0.02-0.2%.

3. The application according to claim 1, characterized in that, The metal chloride salt is at least one selected from aluminum chloride, zinc chloride, and stannous chloride.

4. The application according to claim 1, characterized in that, The preparation method of the coal-based adsorbent includes the following steps: Coal-based adsorbents are obtained by loading metal chloride salts onto porous coal-based supports through impregnation.

5. The application according to claim 4, characterized in that, A porous coal-based carrier and an anhydrous ethanol solution of a metal chloride salt were continuously heated under nitrogen protection and stirring, then naturally cooled to room temperature, and subsequently filtered, washed, dried, and solidified to obtain a coal-based adsorbent.

6. The application according to claim 5, characterized in that, The concentration of the metal chloride in the anhydrous ethanol solution is 10-150 g / L; the mass ratio of porous coal-based carrier to metal chloride is 0.5-1:0.02-0.

2.

7. The application according to claim 6, characterized in that, The mass ratio of porous coal-based carrier to metal chloride salt is 0.5:0.

1.

8. The application according to claim 5, characterized in that, The temperature for heating and reflux is 50-100 ℃.

9. The application according to claim 5, characterized in that, The drying temperature is 100-130 ℃, and the drying time is 5-10 h.

10. The application according to claim 5, characterized in that, The curing temperature is 100-150 ℃, the curing time is 1-5 h, and it is cured under an inert atmosphere.

11. The application according to claim 1, characterized in that, The application includes: mixing coal tar and the coal-based adsorbent for adsorption.

12. The application according to claim 11, characterized in that, The mass ratio of coal-based adsorbent to coal tar is 0.5-5:

1.

13. The application according to claim 11, characterized in that, The adsorption temperature is 10-80 ℃, the adsorption time is 1-3 h, and the adsorption is carried out by mechanical stirring or magnetic stirring at a speed of 100-1000 rpm.

14. The application according to claim 11, characterized in that, The application also includes: eluting the adsorbed coal-based adsorbent with an organic solvent, filtering and collecting the eluent, distilling off the phenol, and reusing the separated organic solvent; drying the solid phase and reusing it.