A method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater

Abstract

The present invention belongs to the technical field of high-value utilization of organic solid wastes, and particularly relates to a method for preparing porous activated carbon by coupling carbonization of plant dyeing residues with activation of printing and dyeing wastewater. In the present invention, plant dyeing waste residues are carbonized, and the carbonized residue-based biochar is used to adsorb organic pollutants in printing and dyeing wastewater. At the same time, the residue-based biochar is chemically activated by the strong alkalinity of the printing and dyeing wastewater, and then subjected to two high-temperature activations to obtain porous activated carbon. The preparation method of the present invention is simple, can effectively remove organic pollutants in printing and dyeing wastewater, saves a large amount of activators, and at the same time improves the specific surface area of the prepared porous activated carbon.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-value utilization of organic solid wastes, and particularly relates to a method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater. Background Art

[0002] Plant dyeing refers to a method of dyeing the object to be dyed by extracting pigments from various naturally growing plants containing pigments in nature. The plant dyes extracted by this process only account for 3-5% of the plants, and more than 95% of the plants are discarded as waste residues. And a certain amount of wastewater will be generated during the printing and dyeing process. The proportion of organic pollutants in the wastewater is relatively high, and it is strongly alkaline. If these wastes are put into the environment, they will inevitably cause pollution and affect human health. It is urgent to develop high-value utilization technologies for plant dyeing residues and printing and dyeing wastewater to solve the non-point source pollution caused by plant dyeing wastes and boost the green development of the plant dyeing process. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies existing in the prior art. In view of the large amount of solid waste in the high plant dyeing process and the strong alkalinity of printing and dyeing wastewater, which has a large pollution attribute as waste, the present invention provides a method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater. Carbonize the plant dyeing waste residues, use the waste residue-based biochar after carbonization to adsorb the organic pollutants in the printing and dyeing wastewater, and then use the strong alkalinity of the printing and dyeing wastewater to chemically activate the waste residue-based biochar.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater, comprising the following steps:

[0006] (1) High-temperature carbonize the plant dyeing residues under a N2 protection atmosphere to obtain waste residue-based biochar;

[0007] (2) Immerse the above waste residue-based biochar in the printing and dyeing wastewater for 16-24 h, then stir well at 80 °C, and evaporate the water to dryness to obtain dry biochar;

[0008] (3) High-temperature activate the biochar obtained in step (2);

[0009] (4) Put the bio-activated carbon after high-temperature activation in step (3) into a tubular furnace, introduce CO2, and perform secondary activation at high temperature to obtain porous activated carbon.

[0010] Further, the plant dyeing residues described in step (1) include but are not limited to chestnut shells, pomegranate peels, and water wisteria.

[0011] Furthermore, the high temperature carbonization temperature in step (1) is 600-800° C., and the carbonization time is 2-4 hours.

[0012] Furthermore, the mass ratio of the waste residue-based biochar to the printing and dyeing wastewater in step (2) is 1:10-40.

[0013] Furthermore, the temperature of the high temperature activation in step (3) is 700-1000° C., and the activation time is 2-3 hours.

[0014] Furthermore, the temperature of the secondary activation in step (4) is 900-1100° C., and the activation time is 3-5 hours.

[0015] The beneficial effects of the present invention are as follows: waste residue-based biochar can effectively reduce the COD of printing and dyeing wastewater by up to 95%; the prepared porous activated carbon has a specific surface area of ​​>650m 2 / g. By adopting the method provided by the present invention, the organic pollutant components in the printing and dyeing wastewater are stabilized and safely disposed, and a large amount of activating agent is also saved, and the specific surface area of ​​the obtained porous activated carbon is effectively improved. Thus, the purpose of treating waste with waste is achieved, and the effect of energy saving and emission reduction is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the preparation process of porous activated carbon by carbonization of plant dye residues coupled with activation of printing and dyeing wastewater. DETAILED DESCRIPTION

[0017] Example 1

[0018] S1: The chestnut shell residue after plant dyeing is subjected to high temperature carbonization at 700°C in a N2 protective atmosphere for 3 hours to obtain chestnut shell waste residue-based biochar.

[0019] S2: The above-mentioned chestnut shell waste residue-based biochar and printing and dyeing wastewater are fully immersed in a mass ratio of 1:30 for 24 hours, and then fully stirred at 80°C to evaporate the water and obtain the dried biochar.

[0020] S3: Activate the dried biochar at 1000°C for 3h.

[0021] S4: The biological activated carbon treated in step S3 is introduced into CO2 and secondary activated at 1000°C for 3 hours to obtain porous activated carbon.

[0022] The specific surface area of ​​the porous activated carbon obtained is 673m 2 / g, the iodine adsorption value is 569mg / L, and the COD in printing and dyeing wastewater is reduced by 95%.

[0023] Example 2

[0024] S1: Carbonize the plant-dyed chestnut shell residue at 800 °C under a nitrogen protection atmosphere for 3 h to obtain chestnut shell waste residue-based biochar.

[0025] S2: Immerse the above chestnut shell waste residue-based biochar and printing and dyeing wastewater at a mass ratio of 1:30 for 16 h, then stir well at 80 °C to evaporate the water, and obtain the dried biochar.

[0026] S3: Activate the above dried biochar at 800 °C for 2 h.

[0027] S4: Pass the bioactivated carbon treated in step S3 through CO2 and perform secondary activation at 900 °C for 3 h to obtain porous activated carbon.

[0028] The specific surface area of the obtained porous activated carbon is 652 m 2 / g, the iodine adsorption value is 526 mg / L, and the COD in the printing and dyeing wastewater is reduced by 90%.

[0029] Example 3

[0030] S1: Carbonize the plant-dyed chestnut shell residue at 700 °C under a nitrogen protection atmosphere for 3 h to obtain chestnut shell waste residue-based biochar.

[0031] S2: Immerse the above chestnut shell waste residue-based biochar and printing and dyeing wastewater at a mass ratio of 1:40 for 16 h, then stir well at 80 °C to evaporate the water, and obtain the dried biochar.

[0032] S3: Activate the above dried biochar at 1000 °C for 2 h.

[0033] S4: Pass the bioactivated carbon treated in step S3 through CO2 and perform secondary activation at 1000 °C for 3 h to obtain porous activated carbon.

[0034] The specific surface area of the obtained porous activated carbon is 665 m 2 / g, the iodine adsorption value is 516 mg / L, and the COD in the printing and dyeing wastewater is reduced by 95%.

[0035] Example 4

[0036] S1: Carbonize the plant-dyed chestnut shell residue at 700 °C under a nitrogen protection atmosphere for 2 h to obtain chestnut shell waste residue-based biochar.

[0037] S2: Immerse the above chestnut shell waste residue-based biochar and printing and dyeing wastewater at a mass ratio of 1:20 for 16 h, then stir well at 80 °C to evaporate the water, and obtain the dried biochar.

[0038] S3: Activate the above dried biochar at 1000 °C for 3 h.

[0039] S4: Feed the biologically activated carbon after the treatment in step S3 into CO2, and conduct secondary activation at 1000 °C for 5 h to obtain porous activated carbon.

[0040] The specific surface area of the obtained porous activated carbon is 685 m 2 / g, the iodine adsorption value is 596 mg / L, and the COD in the printing and dyeing wastewater is reduced by 88%.

[0041] Comparative Example 1

[0042] S1: Subject the plant-dyed chestnut shell residue to high-temperature carbonization at 800 °C under a nitrogen protection atmosphere for 3 h to obtain chestnut shell waste residue-based biochar.

[0043] S2: Immerse the above chestnut shell waste residue-based biochar and printing and dyeing wastewater in a mass ratio of 1:30 for 16 h, then stir thoroughly at 80 °C, evaporate the water, and obtain the dried biochar.

[0044] S3: Activate the above dried biochar at 800 °C for 2 h to obtain porous activated carbon.

[0045] The specific surface area of the obtained porous activated carbon is 352 m 2 / g, the iodine adsorption value is 296 mg / L, and the COD in the printing and dyeing wastewater is reduced by 82%.

[0046] Comparative Example 2

[0047] S1: Subject the plant-dyed chestnut shell residue to high-temperature carbonization at 700 °C under a nitrogen protection atmosphere for 3 h to obtain chestnut shell waste residue-based biochar.

[0048] S2: Immerse the above chestnut shell waste residue-based biochar and printing and dyeing wastewater in a mass ratio of 1:30 for 24 h, then stir thoroughly at 80 °C, evaporate the water, and obtain the dried biochar.

[0049] S3: Activate the above dried biochar at 800 °C for 3 h to obtain porous activated carbon.

[0050] The specific surface area of the obtained porous activated carbon is 284 m 2 / g, the iodine adsorption value is 219 mg / L, and the COD in the printing and dyeing wastewater is reduced by 73%.

[0051] Comparative Example 3

[0052] S1: Subject the plant-dyed chestnut shell residue to high-temperature carbonization at 700 °C under a nitrogen protection atmosphere for 3 h to obtain chestnut shell waste residue-based biochar.

[0053] S2: Feed the above chestnut shell waste residue-based biochar into the activation at 1000 °C for 3 h.

[0054] S4: Pass the biologically activated carbon processed in step S3 into CO2, and perform secondary activation at 1000 °C for 3 h to obtain porous activated carbon.

[0055] The specific surface area of the obtained porous activated carbon is 235 m 2 / g, and the iodine adsorption value is 197 mg / L.

Claims

1. A method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater, characterized in that, The following steps are involved: (1) subjecting plant dyeing residues to high-temperature carbonization under a nitrogen atmosphere, wherein the high-temperature carbonization temperature is 600-800° C. and the carbonization time is 2-4 hours to obtain waste residue-based biochar; (2) fully immersing the above-mentioned waste residue-based biochar in printing and dyeing wastewater for 16-24 hours, then fully stirring at 80° C., evaporating the water to obtain dry biochar; (3) subjecting the biochar obtained in step (2) to high-temperature activation, wherein the temperature of the high-temperature activation is 700-1000° C. and the activation time is 2-3 h; (4) placing the biological activated carbon after high temperature activation in step (3) into a tubular furnace and introducing CO2 to perform secondary activation at high temperature. The temperature of the secondary activation is 900-1100° C. and the activation time is 3-5 hours to obtain porous activated carbon.

2. The method for preparing porous activated carbon by coupling carbonization of plant dyeing residues with activation of printing and dyeing wastewater according to claim 1, characterized in that, The plant dye residues in step (1) include one or more of chestnut shells, pomegranate peels, and water chestnut.

3. The method for preparing porous activated carbon by coupling carbonization of plant dyeing residues and activation of printing and dyeing wastewater according to claim 1, wherein, The mass ratio of the waste residue-based biochar to the printing and dyeing wastewater in step (2) is 1:10-40.

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