CN115957793A - A kind of biochar-based catalyst and its synthesis method and application - Google Patents

Abstract

The invention provides a biochar-based catalyst and a synthesis method and application thereof, and relates to the technical field of atmospheric pollution control. The biochar-based catalyst comprises biochar, the specific surface area of the biochar-based redox reaction catalyst is 360-800 m/g, and the first step is to perform acid washing pretreatment on wheat straws: treating wheat straws with a nitric acid solution with a certain concentration, and then cleaning with deionized water to obtain acid-washed pretreated wheat straws; and step two, grinding the wheat straws to obtain the wheat straw powder with the grain diameter of 40-200 meshes, and then using the wheat straw powder at the temperature of 600-800 ℃ under the nitrogen atmosphere. The high-activity biochar-based catalyst has the catalytic characteristics of multi-element metals, the mixture of carbon and salt presents high-efficiency performance for synchronously removing VOCs in an inert gas oxidation technical system, agricultural waste straws are used as biochar raw materials, and the straws are washed by hydrochloric acid to be reducing agents, so that various metal ions are converted into high-activity zero-valent metal catalyst particles.

Description

A kind of biochar-based catalyst and its synthesis method and application

technical field

The invention relates to the technical field of air pollution control, in particular to a biochar-based catalyst and its synthesis method and application.

Background technique

Carbonyl sulfide (COS) and carbon disulfide (CS2) widely exist in the atmosphere, and COS is the main sulfur-containing gas in the troposphere and bottom stratosphere. Their sources can be divided into natural sources and anthropogenic sources. COS and CS2 are discharged into the atmosphere during industrial production and use, which will cause serious pollution and harm to the environment and the human body. In the atmosphere, CS2 can also be catalytically oxidized to COS. Trace amounts of COS and CS2 in industrial production have a poisonous effect on the catalyst, which seriously affects its catalytic effect and service life. Because COS and CS2 will generate hydrogen sulfide (H2S) through slow hydrolysis reaction, which will corrode production equipment, which not only brings great economic losses to industrial production, but also increases equipment investment and product costs. At the same time, the inhalation of COS and CS2 has great harm to human health. COS and CS2 in yellow phosphorus tail gas are typical organic sulfur gases that coexist. The premise of purification and resource utilization of yellow phosphorus tail gas must be to remove COS and CS2 at the same time.

The invention provides a biochar-based catalyst and its synthesis method and application, wherein the raw material of the biochar-based catalyst is carbonized with straw, and the VOCs are adsorbed, treated and utilized by washing with hydrochloric acid, and no harmful pollutants are produced. It can solve the disposal problem of biomass waste and effectively prevent and control air pollution.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a biochar-based catalyst and its synthesis method and application, which solves the problem of using straw for carbonization, and adopting hydrochloric acid washing for adsorption and treatment of VOCs, without producing harmful pollutants, both It can solve the disposal problem of biomass waste and effectively prevent and control the problem of air pollution.

In order to achieve the above object, the present invention is achieved through the following technical solutions: a biochar-based catalyst and its synthesis method and application, including biochar, the specific surface area of the biochar-based redox reaction catalyst is 360m/g～800m/g g.

Preferably, a synthetic method of a biochar-based catalyst, comprising the following steps;

Step 1. First, carry out pickling pretreatment on the wheat straw: first treat the wheat straw with a certain concentration of nitric acid solution, and then wash it with deionized water to obtain the pickling pretreated wheat straw;

Step 2, crushing the wheat straw to a particle size of 40-200 mesh to obtain wheat straw powder, and then roasting the wheat straw powder obtained in step 1 for 1-3 hours at a temperature of 600-800° C. under a nitrogen atmosphere to obtain carbon powder;

Step 3: Add biochar, thionyl chloride, and dimethylformamide to mix evenly, then impregnate at a temperature of 40-90°C under ultrasonic conditions for 1-3 hours, wash with anhydrous tetrahydrofuran, and vacuum filter to obtain Formyl chloride tea stem-based biochar adsorption catalyst.

Preferably, the first step includes the steps of drying the cleaned straw at 105°C for 12 hours, crushing it through a grinder and passing it through a 40-200 mesh sieve; pyrolyzing the obtained 1000g straw powder in a tube furnace at 600°C For 3 hours, the heating rate was 5°C/min; the residue was first washed with 0.1mol/L hydrochloric acid, and then washed three times with appropriate amount of deionized water until neutral. The product was dried at 105°C for 12 hours and then taken out for use.

Preferably, the step 2 further includes the steps of adding the mixture of carbon powder, charcoal and salt obtained in step 2 into the nitric acid solution and mixing evenly, reacting at a temperature of 80°C for 2 hours, filtering, washing, and drying to obtain biochar .

Preferably, the second step further includes the step that the straw used in the carbonization is derived from at least one of wheat, rice, corn, potato, rapeseed, cotton, and sugar cane.

Preferably, the charcoal and salt mixture are heated up under an inert gas atmosphere, stopped heating after high-temperature doping treatment, cooled to room temperature, and sequentially pickled, washed and dried to obtain biochar co-doped with nitrogen and phosphorus Based on redox reaction catalyst, the temperature of high temperature doping treatment is 700℃～900℃.

Preferably, the inert gas atmosphere is a nitrogen atmosphere or an argon atmosphere, the heating rate is 5°C/min˜10°C/min, and the holding time is 6h˜10h.

Preferably, the application of a biochar-based catalyst, the biochar-based catalyst is mainly used for VOCs as the treatment conditions, the drum rotation speed of the reactor is kept at 0.2-2r/min, the pH is 6.5-7.5, and the temperature is 25 ~30°C, the concentration of VOCs treated is 350-1000mg/m2.

The invention provides a biochar-based catalyst as well as its synthesis method and application. Has the following beneficial effects:

In the present invention, the high-activity biochar-based catalyst has the catalytic characteristics of multiple metals, and the mixture of carbon and salt in the inert gas oxidation technology system presents a high-efficiency performance for synchronous removal of VOCs. The agricultural waste straw is the raw material of biochar, and the straw is washed with hydrochloric acid. The reducing agent converts various metal ions into highly active zero-valent metal catalyst particles.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment one:

The embodiment of the present invention provides a biochar-based catalyst and its synthesis method and application, including biochar, and the specific surface area of the biochar-based redox reaction catalyst is 700m/g.

Step 1. First, carry out pickling pretreatment on the wheat straw: first treat the wheat straw with a certain concentration of nitric acid solution, and then wash it with deionized water to obtain the pickling pretreated wheat straw;

Step 2, crushing the wheat straw to a particle size of 50 mesh to obtain wheat straw powder, and then roasting the wheat straw powder obtained in Step 1 for 2 hours at a temperature of 700° C. under a nitrogen atmosphere to obtain carbon powder;

Step 3: Add biochar, thionyl chloride, and dimethylformamide to mix evenly, then impregnate and react for 1.5 hours under ultrasonic conditions at a temperature of 80°C, wash with anhydrous tetrahydrofuran, and vacuum filter to obtain formyl chloride tea The stalk-based biochar adsorption catalyst has the catalytic characteristics of multiple metals through the high-activity biochar-based catalyst. The carbon and salt mixture in the inert gas oxidation technology system shows high efficiency for the simultaneous removal of VOCs. The agricultural waste straw is used as a raw material for biochar , the straw was washed with hydrochloric acid as a reducing agent to convert various metal ions into highly active zero-valent metal catalyst particles.

Step 1 includes the following steps: dry the cleaned straw at 105°C for 12 hours, then pass it through a grinder and pass through a 50-mesh sieve; pyrolyze 1000g of the obtained straw powder in a tube furnace at 600°C for 3 hours, with a heating rate of 5°C /min; the residue was first washed with 0.1mol/L hydrochloric acid, and then washed three times with an appropriate amount of deionized water until neutral. The product was dried at 105°C for 12 hours and then taken out for use.

The second step also includes the steps of adding the mixture of carbon powder, charcoal and salt obtained in the second step into the nitric acid solution, mixing evenly, reacting at 80° C. for 1.4 hours, filtering, washing and drying to obtain biochar.

The second step also includes the following steps, the straw used in the carbonization is derived from wheat.

The mixture of charcoal and salt is heated up in an inert gas atmosphere, after high-temperature doping treatment, the heating is stopped, cooled to room temperature, and then acid-washed, washed with water and dried in sequence to obtain a nitrogen-phosphorous co-doped biochar-based redox reaction catalyst , the temperature of the high temperature doping treatment is 750°C.

The inert gas atmosphere is a nitrogen atmosphere or an argon atmosphere, the heating rate is 7°C/min, and the holding time is 8h.

Biochar-based catalysts are mainly used for VOCs as treatment conditions, keep the drum rotation speed of the reactor at 1.5r/min, pH at 7, temperature at 25°C, and the concentration of VOCs to be treated is 900mg/m3.

Embodiment two:

The embodiment of the present invention provides a biochar-based catalyst and its synthesis method and application, including biochar, and the specific surface area of the biochar-based redox reaction catalyst is 700m/g.

Step 1. First, carry out pickling pretreatment on the wheat straw: first treat the wheat straw with a certain concentration of nitric acid solution, and then wash it with deionized water to obtain the pickling pretreated wheat straw;

Step 2, crushing the wheat straw to a particle size of 50 mesh to obtain wheat straw powder, and then roasting the wheat straw powder obtained in Step 1 for 2 hours at a temperature of 700° C. under a nitrogen atmosphere to obtain carbon powder;

Step 3, further add biochar, thionyl chloride, and dimethylformamide and mix evenly, then impregnate and react for 1.5 hours under ultrasonic conditions at a temperature of 90°C, wash with anhydrous tetrahydrofuran, and vacuum filter to obtain formyl chloride tea The stalk-based biochar adsorption catalyst has the catalytic characteristics of multiple metals through the high-activity biochar-based catalyst. The carbon and salt mixture in the inert gas oxidation technology system shows high efficiency for the simultaneous removal of VOCs. The agricultural waste straw is used as a raw material for biochar , the straw was washed with hydrochloric acid as a reducing agent to convert various metal ions into highly active zero-valent metal catalyst particles.

Step 1 includes the following steps: dry the cleaned straw at 105°C for 12 hours, then pass it through a grinder and pass through a 50-mesh sieve; pyrolyze 1000g of the obtained straw powder in a tube furnace at 600°C for 3 hours, with a heating rate of 5°C /min; the residue was first washed with 0.1mol/L hydrochloric acid, and then washed three times with an appropriate amount of deionized water until neutral. The product was dried at 105°C for 12 hours and then taken out for use.

The second step also includes the steps of adding the carbon powder, charcoal and salt mixture obtained in the second step into the nitric acid solution and mixing evenly, reacting at a temperature of 100° C. for 2 hours, filtering, washing and drying to obtain biochar.

The second step also includes the following steps, the straw used in the carbonization is derived from wheat.

The mixture of charcoal and salt is heated up in an inert gas atmosphere, after high-temperature doping treatment, the heating is stopped, cooled to room temperature, and then acid-washed, washed with water and dried in sequence to obtain a nitrogen-phosphorous co-doped biochar-based redox reaction catalyst , the temperature of the high-temperature doping treatment is 1000°C.

The inert gas atmosphere is a nitrogen atmosphere or an argon atmosphere, the heating rate is 7°C/min, and the holding time is 8h.

Biochar-based catalysts are mainly used for VOCs as treatment conditions, keep the drum rotation speed of the reactor at 1.5r/min, pH at 7, temperature at 25°C, and the concentration of VOCs to be treated is 900mg/m3.

Embodiment three:

The embodiment of the present invention provides a biochar-based catalyst and its synthesis method and application, including biochar, and the specific surface area of the biochar-based redox reaction catalyst is 700m/g.

Step 1. First, carry out pickling pretreatment on the wheat straw: first treat the wheat straw with a certain concentration of nitric acid solution, and then wash it with deionized water to obtain the pickling pretreated wheat straw;

Step 2, crushing the wheat straw to a particle size of 50 mesh to obtain wheat straw powder, and then roasting the wheat straw powder obtained in step 1 for 4 hours at a temperature of 700°C under a nitrogen atmosphere to obtain carbon powder;

Step 3, further adding biochar, thionyl chloride, and dimethylformamide to mix evenly, then immersing and reacting for 5 hours under ultrasonic conditions at a temperature of 80°C, washing with anhydrous tetrahydrofuran, and vacuum filtering to obtain formyl chloride tea stems The biochar-based adsorption catalyst has the catalytic characteristics of multiple metals through the high-activity biochar-based catalyst. The mixture of carbon and salt in the inert gas oxidation technology system presents a high-efficiency performance for the simultaneous removal of VOCs. Agricultural waste straw is the raw material for biochar. Straw hydrochloric acid washing is used as a reducing agent to convert various metal ions into highly active zero-valent metal catalyst particles.

Step 1 includes the following steps: dry the cleaned straw at 105°C for 12 hours, then pass it through a grinder and pass through a 50-mesh sieve; pyrolyze 1000g of the obtained straw powder in a tube furnace at 600°C for 3 hours, with a heating rate of 5°C /min; the residue was first washed with 0.1mol/L hydrochloric acid, and then washed three times with an appropriate amount of deionized water until neutral. The product was dried at 105°C for 12 hours and then taken out for use.

The second step also includes the steps of adding the carbon powder, charcoal and salt mixture obtained in the second step into the nitric acid solution, mixing evenly, reacting at 80° C. for 6 hours, filtering, washing and drying to obtain biochar.

The second step also includes the following steps, the straw used in the carbonization is derived from wheat.

The mixture of charcoal and salt is heated up in an inert gas atmosphere, after high-temperature doping treatment, the heating is stopped, cooled to room temperature, and then acid-washed, washed with water and dried in sequence to obtain a nitrogen-phosphorous co-doped biochar-based redox reaction catalyst , the temperature of the high temperature doping treatment is 750°C.

The inert gas atmosphere is a nitrogen atmosphere or an argon atmosphere, the heating rate is 7°C/min, and the holding time is 8h.

Biochar-based catalysts are mainly used for VOCs as treatment conditions, keep the drum rotation speed of the reactor at 1.5r/min, pH at 7, temperature at 25°C, and the concentration of VOCs to be treated is 900mg/m3.

temperature time Surface area 500～1700 Embodiment one 80 2 900 Embodiment two 90 2 400 Embodiment Three 80 4 200

Specific parameter table 1

It can be seen that the adsorption effect of the biochar-based catalyst in the present invention is the best.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (8)

1. A biochar-based catalyst, comprising biochar, characterized in that the specific surface area of the biochar-based redox reaction catalyst is 360m/g-800m/g. 2. a synthetic method of biochar-based catalyst, a kind of biochar-based catalyst according to claim 1, is characterized in that, comprises the following steps; Step 1. First, carry out pickling pretreatment on the wheat straw: first treat the wheat straw with a certain concentration of nitric acid solution, and then wash it with deionized water to obtain the pickling pretreated wheat straw; Step 2, crushing the wheat straw to a particle size of 40-200 mesh to obtain wheat straw powder, and then roasting the wheat straw powder obtained in step 1 for 1-3 hours at a temperature of 600-800° C. under a nitrogen atmosphere to obtain carbon powder; Step 3: Add biochar, thionyl chloride, and dimethylformamide to mix evenly, then impregnate at a temperature of 40-90°C under ultrasonic conditions for 1-3 hours, wash with anhydrous tetrahydrofuran, and vacuum filter to obtain Formyl chloride tea stem-based biochar adsorption catalyst. 3. The synthetic method of a kind of biochar-based catalyst according to claim 2, characterized in that: said step 1 comprises the following steps, drying the cleaned stalks at 105°C for 12 hours, and then crushing them through a grinder. 40-200 mesh sieve; 1000g of straw powder obtained was pyrolyzed in a tube furnace at 600°C for 3 hours, and the heating rate was 5°C/min; the residue was first washed with 0.1mol/L hydrochloric acid, and then washed three times with appropriate amount of deionized water to Neutral, the product was dried at 105°C for 12 hours and then taken out for use. 4. the synthetic method of a kind of biochar-based catalyst according to claim 2, is characterized in that: described step 2 also comprises the following steps, step 2 gained carbon powder, charcoal and salt mixture are added in the nitric acid solution and mix homogeneously , react at a temperature of 70-90°C for 1-3h, filter, wash, and dry to obtain biochar. 5. The synthesis method of a kind of biochar-based catalyst according to claim 2, characterized in that: said step 2 also includes the following steps, the straw used in carbonization is derived from wheat, rice, corn, potatoes, rape , cotton, sugarcane at least one. 6. the synthetic method of a kind of biochar-based catalyst according to claim 2, is characterized in that: described carbon, salt mixture heat up under inert gas atmosphere, stop heating after high-temperature doping treatment, cool to room temperature, And pickling, washing and drying are carried out in sequence to obtain a biochar-based redox reaction catalyst co-doped with nitrogen and phosphorus, and the temperature of high-temperature doping treatment is 700°C to 900°C. 7. The synthesis method of a biochar-based catalyst according to claim 2, characterized in that: the inert gas atmosphere is a nitrogen atmosphere or an argon atmosphere, and the heating rate is 5°C/min～10°C/min, And the holding time is 6h ~ 10h. 8. The application of a biochar-based catalyst, a kind of biochar-based catalyst according to claim 1, characterized in that: the biochar-based catalyst is mainly used for VOCs as a treatment condition, keeping the drum of the reactor The speed is 0.2-2r/min, the pH is 6.5-7.5, the temperature is 25-30°C, and the concentration of VOCs to be treated is 350-1000mg/m.