CN108126677A - A kind of preparation method of carbon composite for Acid Dye Wastewater processing - Google Patents

Abstract

The invention discloses a method for preparing a composite carbon material used for acid dye wastewater treatment, and belongs to the technical field of carbon material preparation. In this method, coal tar pitch is used as the carbon source, nano-magnesia is used as the template, and potassium hydroxide is used as the activator to prepare porous carbon with a large amount of mesopore structure, and then concentrated nitric acid is used to acidify the surface of the porous carbon; Methyl acrylate and methanol were used as raw materials to prepare 2.0-generation polyamidoamine dendrimers by "one-pot method". Finally, the acidified porous carbon and the prepared polyamidoamine were mixed at a mass ratio of 4:1 to 6: The ratio of 1 was mixed and stirred in an aqueous solution at 35°C for several hours, and then dried to obtain a composite carbon material with polyamide amine on the surface of mesoporous carbon. The raw materials used in the composite carbon material prepared by the invention are low in price, wide in sources and simple in process, and the composite carbon material exhibits excellent adsorption and removal performance on acid dyes in waste water.

Description

A preparation method of composite carbon material for acid dye wastewater treatment

technical field

The invention belongs to the technical field of sewage treatment, and in particular relates to a method for preparing a composite carbon material for acid dye wastewater treatment.

Background technique

According to statistics, nearly 100,000 different dyes are still produced and used in my country every year, and nearly 1.6 million tons of dyes are produced and used every year, and 10% to 15% of the amount cannot be fully utilized and directly discharged into rivers and lakes. Dye wastewater will pollute 20 tons of water. Dye wastewater has become one of the key pollution sources of water system environment. If this kind of wastewater is not treated in a timely and effective manner, highly toxic dye pollutants will enter the groundwater body, which will not only have adverse effects on the ecological environment and human health, but also directly endanger human health and seriously damage the water body, soil and ecological environment; Therefore, as people's awareness of environmental protection continues to increase, how to effectively treat dye wastewater has received more and more attention in recent years. The commonly used methods for treating dye wastewater at home and abroad include physical, chemical and biological methods. Due to its simple operation and the excellent performance of efficiently concentrating low-concentration pollutants under normal temperature and pressure, the adsorption method has also been widely used in the treatment of dye wastewater. Adsorbent is the core of adsorption technology. Adsorbents currently being studied for the treatment of dye wastewater include activated carbon, polymers, nano-metal oxides, molecular sieves, etc., but they have low adsorption efficiency, small capacity or small application range, and poor regeneration. High cost and other defects, so high-performance adsorbents must be developed to meet the needs of dye wastewater treatment.

Contents of the invention

In order to overcome the deficiencies of existing adsorbents, the purpose of this invention is to provide a high-performance method for preparing a composite carbon material for the treatment of acid dye wastewater, in order to solve the dye wastewater in the prior art, especially the difficulty in decolorizing acid dye wastewater. Unable to meet emission standards and other technical problems.

The purpose of the present invention is achieved through the following technical solutions.

The invention provides a method for preparing a composite carbon material for acid dye wastewater treatment. The method aims at acid dye molecules with large molecular sizes, firstly prepares porous carbon containing a large number of mesopores, and then grafts polyamide on the surface of the porous carbon Amine (PAMAM), finally makes acid dye adsorbent, concrete steps are as follows:

(1) Pretreatment of reactants: put coal tar pitch into a mortar, add nano-magnesium oxide and mix evenly, then add potassium hydroxide that has been ground to powder, and mix evenly to obtain reactants.

Wherein: the mass ratio of the coal tar pitch to the nano magnesium oxide is between 1/10 and 2/1; the mass ratio of the coal tar pitch and potassium hydroxide is between 1/2 and 1/4.

(2) Preparation of porous carbon: put the reactant obtained in step (1) into a corundum porcelain boat, place the corundum porcelain boat in a tube furnace, and ventilate and exhaust the tube furnace with flowing argon Then raise the temperature of the tube furnace to 200°C at a heating rate of 3°C/min, keep the temperature constant for 30 minutes, continue to raise the temperature of the tube furnace to 800-900°C at a heating rate of 3°C/min, and keep the temperature at this temperature for 60 minutes After that, the temperature was naturally lowered to room temperature; finally, the obtained product was taken out, ground and pulverized, washed with hydrochloric acid, washed with distilled water and dried to obtain porous carbon.

(3) Surface acidification treatment of porous carbon: 1 g of porous carbon obtained in step (2), 9 mL of concentrated nitric acid with a mass concentration of 68%, and 6 mL of distilled water are placed in an Erlenmeyer flask, and magnetically stirred for 3 hours at 60° C. , filter the solution, wash the treated porous carbon with distilled water until the solution is neutral, and dry the washed porous carbon to obtain a surface acidified porous carbon.

(4) Preparation of 2.0-generation polyamidoamine: First, add 0.01 mole of ethylenediamine and 0.1 mole of anhydrous methanol into a 250 mL three-necked flask in sequence, slowly add 0.04 mole of methyl acrylate dropwise under stirring conditions, At the reaction temperature of ℃, react for 12h; then directly dropwise add 0.04 mole of ethylenediamine for amidation reaction, and add 0.02 mole of anhydrous methanol at the same time, at the reaction temperature of 20℃, react for 24h to obtain 1.0 generation of PAMAM-free Water methanol solution, under stirring conditions, slowly add 0.08 moles of methyl acrylate dropwise, and react for 12 hours at a reaction temperature of 20°C; then add 0.08 moles of ethylenediamine dropwise for amidation reaction, and simultaneously add 0.04 moles of Anhydrous methanol was reacted at a reaction temperature of 30°C for 12 hours, and finally anhydrous methanol was distilled off under reduced pressure to obtain 2.0-generation polyamidoamine dendrimers.

(5) Preparation of composite carbon material: mix the surface acidified porous carbon obtained in step (3) with the 2.0 generation polyamidoamine obtained in step (4), add 40mL of deionized water, clean and dry after ultrasonic dispersion A composite carbon material is obtained; the mass ratio of the surface-acidified porous carbon to the 2.0-generation polyamidoamine is 4/1˜6/1.

Further, in step (1), the quality of the coal tar pitch is 2g, the quality of the nano magnesium oxide is 19g, and the quality of the potassium hydroxide is 6g; in the step (2), the tubular The final temperature of the furnace heating was 850°C.

Further, in step (3), the drying is constant temperature drying.

Further, in step (5), the drying is vacuum drying.

Compared with the prior art, the present invention has the following technical effects:

1. Coal tar pitch is used as the carbon source, and the source of carbon material is abundant and the price is low.

2. The prepared porous carbon is rich in a large number of mesopores, which is conducive to the diffusion and adsorption of dye molecules with larger molecular sizes.

3. The surface of the composite carbon material contains a large number of polyamidoamine dendrimers, which can effectively form chemical adsorption with acid dye molecules, and exhibit excellent adsorption performance for acid dyes.

4. The acidified porous carbon can be directly mixed with less amount of PAMAM to prepare a composite carbon material, which has the advantages of simple process and low cost.

Description of drawings

Fig. 1 is a nitrogen adsorption-desorption isotherm diagram of composite carbon materials prepared in Examples 1, 2, and 3 of the present invention.

Fig. 2 is the pore size distribution diagram of the composite carbon materials prepared in Examples 1, 2 and 3 of the present invention.

Fig. 3 is the adsorption isotherm of acid orange adsorbed by composite carbon materials prepared in Examples 1, 2, and 3 of the present invention.

Detailed ways

The present invention is described in detail below in conjunction with specific examples, but the present invention is not limited to following examples.

Example 1

The specific preparation process of composite carbon material PC4 is as follows:

(1) Pretreatment of the reactant: take 6g of potassium hydroxide and put it into a mortar to grind to powder, weigh 19g of nano-magnesium oxide, weigh 2g of coal tar pitch and mix with potassium hydroxide, stir and mix evenly to obtain the reactant .

(2) Preparation of porous carbon: put the pretreated reactant in step (1) into a corundum porcelain boat, then put the corundum porcelain boat into a tube furnace, and pass argon gas at a flow rate of 120ml/min for 20min in advance Exhaust the air in the tube-type furnace, then heat the tube-type furnace to 200°C at a heating rate of 3°C/min under an argon atmosphere of 20ml/min, keep the temperature constant for 30min, and continue to heat the tube furnace at a heating rate of 3°C/min The furnace was continuously heated to 850°C, kept at a constant temperature for 60 minutes, and then cooled down to room temperature naturally. Take out the obtained product, put the product in a mortar, grind and pulverize it, pour it into a beaker, prepare 2M hydrochloric acid and pour it into the beaker, ultrasonically vibrate for 2 hours, then stir with a magnetic stirrer for 12 hours, stand for 12 hours for pickling, and then Wash with hot distilled water until neutral, put the cleaned charcoal into a blast drying oven to dry for 24 hours, take it out, grind, pulverize and sieve to obtain porous charcoal.

(3) Surface acidification treatment of porous carbon: 1g of porous carbon obtained in step (2) and 9mL of 68% concentrated nitric acid and 6mL of distilled water are placed in a conical flask, stirred magnetically for 3 hours at 60°C, and filtered out Solution, the treated porous carbon was washed with distilled water until the solution was neutral, and the washed porous carbon was dried in a constant temperature (110° C.) oven for 36 hours to obtain surface acidified porous carbon.

(4) Preparation of 2.0-generation PAMAM: First, add 0.01 moles of ethylenediamine and 0.1 moles of anhydrous methanol into a 250ml three-necked flask in sequence, and slowly add 0.04 moles of methyl acrylate dropwise under stirring conditions. Under the reaction temperature, react for 12 hours; then directly dropwise add ethylenediamine with a molar ratio of 0.04 moles for amidation reaction, and add anhydrous methanol with a molar ratio of 0.02 moles at the same time, and react for 24 hours at a reaction temperature of 20°C to obtain 1.0 Substitute PAMAM in anhydrous methanol solution, slowly drop 0.08 mole of methyl acrylate under stirring condition, and react for 12 hours at a reaction temperature of 20°C; then add 0.08 mole of ethylenediamine dropwise for amidation reaction, and simultaneously Add 0.04 moles of anhydrous methanol, react at a reaction temperature of 30°C for 12 hours, and finally distill off anhydrous methanol under reduced pressure to obtain 2.0 generation polyamidoamine dendrimers (PAMAM).

(5) Preparation of composite carbon material: Mix the porous carbon obtained in step (3) with the PAMAM obtained in step (4) at a mass ratio of 4:1, add 40 mL of deionized water, and disperse ultrasonically. Stir at 35°C for 12h, wash with distilled water three times, and vacuum-dry at 60°C to obtain a composite carbon material. The resulting composite carbon material is denoted as PC4. Using this material to adsorb acid orange dye, under the condition of pH value 3.2, when the equilibrium concentration is 30mg/L, the equilibrium adsorption capacity is as high as 388mg/g.

Example 2

The specific preparation process of composite carbon material PC5 is as follows:

(1), (2), (3), (4) step is the same as the step of (1-4) in the example 1,

The difference is:

(5) Mix the acidified porous carbon and PAMAM at a mass ratio of 5:1. The resulting composite carbon material is denoted as PC5. The material is used to adsorb acid orange dye. Under the condition of pH value of 3.2, when the equilibrium concentration of acid orange is 25 mg/L, the adsorption capacity reaches 202 mg/g.

Example 3

The specific preparation process of composite carbon material PC6 is as follows:

(1), (2), (3), (4) step is the same as the step of (1-4) in the example 1,

The difference is:

(5) Mix the acidified porous carbon and PAMAM at a mass ratio of 6:1. The resulting composite carbon material is denoted as PC6. The material is used to adsorb acid orange dye. Under the condition of pH value of 3.2, when the equilibrium concentration of acid orange is 45 mg/L, the adsorption capacity reaches 285 mg/g.

Claims (4)

1. A preparation method for a composite carbon material for acid dye wastewater treatment, characterized in that the method concrete steps are as follows: (1) Pretreatment of reactants: put coal tar pitch into a mortar, add nano magnesium oxide and mix evenly, then add potassium hydroxide that has been ground to powder, and mix evenly to obtain reactants; Wherein: the mass ratio of the coal tar pitch and nano magnesium oxide is between 1/10 and 2/1; the mass ratio of the coal tar pitch and potassium hydroxide is between 1/2 and 1/4; (2) Preparation of porous carbon: put the reactant obtained in step (1) into a corundum porcelain boat, place the corundum porcelain boat in a tube furnace, and ventilate and exhaust the tube furnace with flowing argon Then raise the temperature of the tube furnace to 200°C at a heating rate of 3°C/min, keep the temperature constant for 30 minutes, continue to raise the temperature of the tube furnace to 800-900°C at a heating rate of 3°C/min, and keep the temperature at this temperature for 60 minutes Afterwards, the temperature was naturally lowered to room temperature; finally, the obtained product was taken out, ground and pulverized, then pickled with hydrochloric acid, washed with distilled water and dried to obtain porous carbon; (3) Surface acidification treatment of porous carbon: 1 g of porous carbon obtained in step (2), 9 mL of concentrated nitric acid with a mass concentration of 68%, and 6 mL of distilled water are placed in an Erlenmeyer flask, and magnetically stirred for 3 hours at 60° C. , filter out the solution, wash the treated porous carbon with distilled water until the solution is neutral, and dry the washed porous carbon to obtain surface acidified porous carbon; (4) Preparation of 2.0-generation polyamidoamine: First, add 0.01 mole of ethylenediamine and 0.1 mole of anhydrous methanol into a 250 mL three-necked flask in sequence, and slowly add 0.04 mole of methyl acrylate dropwise under stirring conditions, and in 20 At the reaction temperature of ℃, react for 12h; then directly dropwise add 0.04 mole of ethylenediamine for amidation reaction, and add 0.02 mole of anhydrous methanol at the same time, and react for 24h at the reaction temperature of 20℃ to obtain 1.0 generation of PAMAM-free Water methanol solution, under stirring conditions, slowly add 0.08 moles of methyl acrylate dropwise, and react for 12 hours at a reaction temperature of 20°C; then add 0.08 moles of ethylenediamine dropwise for amidation reaction, and simultaneously add 0.04 moles of Anhydrous methanol, at a reaction temperature of 30°C, react for 12 hours, and finally remove anhydrous methanol by distillation under reduced pressure to obtain a 2.0-generation polyamidoamine dendrimer; (5) Preparation of composite carbon material: mix the surface acidified porous carbon obtained in step (3) with the 2.0 generation polyamidoamine obtained in step (4), add 40mL of deionized water, clean and dry after ultrasonic dispersion A composite carbon material is obtained; the mass ratio of the surface-acidified porous carbon to the 2.0-generation polyamidoamine is 4/1˜6/1. 2. a kind of preparation method for the composite carbon material that is used for acid dye wastewater treatment as claimed in claim 1, is characterized in that, in step (1), the quality of described coal tar pitch is 2g, the quality of nano magnesium oxide is 19g, and the quality of potassium hydroxide is 6g; in step (2), the tube furnace heating final temperature is 850°C. 3. a kind of preparation method for the composite carbon material that is used for acid dye wastewater treatment as claimed in claim 1 is characterized in that, in step (3), described drying is constant temperature drying. 4. a kind of preparation method for the composite carbon material that is used for acid dye wastewater treatment as claimed in claim 1, is characterized in that, in step (5), described drying is vacuum drying.