A biochar composite material capable of realizing slow dyeing of acrylic fibers, its preparation method and application

Abstract

The present invention discloses a biochar composite material capable of achieving slow dyeing of acrylic fibers, and a preparation method and application thereof. The present invention uses waste biomass as raw material, controls the pores and oxygen-containing group quantity of the biochar material by a one-step thermal cracking method, adjusts the specific surface area and surface charge properties of the biochar, and prepares a biochar composite material that can be used for slow dyeing of acrylic fibers. The biochar composite material has adsorption selectivity for cationic dyes in multi-component printing and dyeing residual liquid, and the dye adsorbed on the biochar composite material can be slowly desorbed in the dye bath by adjusting the pH value. The dyeing rate of the dye on acrylic fabric is controlled by the desorption process, thereby achieving slow dyeing of the acrylic fabric. The dyeing process can reduce the amount of slow dyeing agent used, and the solution is clarified after dyeing, which can avoid the pollution problem of printing and dyeing wastewater. At the same time, the desorption and regeneration of biochar can avoid the solid waste pollution generated by the biochar after adsorption and use.

Description

Technical Field

[0001] The present invention relates to the field of biochar composites, and particularly to a preparation method of a biochar composite capable of realizing slow dyeing of acrylic fibers. Background Art

[0002] With the rapid development of the economy and the improvement of social productivity, the output of waste biomass has been increasing year by year. Waste biomass includes agricultural waste biomass, urban organic solid waste, industrial organic solid waste, etc. Due to its high organic matter content, it is a potential resource. The resource utilization of waste biomass can not only solve the problem of resource shortage, but also reduce the carbon emissions generated during the corruption process of organic matter.

[0003] Printing and dyeing wastewater has a large volume, high residual dye content, high alkalinity, and complex water quality, making it difficult to treat. Taking acrylic fiber dyeing as an example, during the dyeing process, due to the too-fast combination of dye cations and negatively charged dyeing sites on acrylic fibers, uneven dyeing will occur, and it is necessary to add sodium sulfate and leveling agents to delay the dyeing rate of dyes to achieve a leveling effect. This results in a large amount of salts and surfactants in the dyeing residual liquid, increasing the difficulty of subsequent sewage treatment.

[0004] Currently, the main printing and dyeing wastewater treatment technologies include physical treatment, chemical treatment, and biological treatment. Among them, the adsorption method is simple to operate, has low energy consumption, and no harmful by-products, and is a commonly used method for treating printing and dyeing wastewater. Biochar is a porous carbonaceous material produced by pyrolyzing biomass raw materials under low-oxygen or oxygen-free conditions. Biochar has a high carbon content, high porosity, and rich surface functional groups, and is a low-cost adsorbent. Converting solid waste into biochar to remove pollutants in printing and dyeing wastewater can achieve the dual purposes of solid waste recycling and water pollution elimination. However, printing and dyeing wastewater is a complex pollution system, and traditional biochar cannot achieve selective adsorption of dyes in printing and dyeing wastewater. In addition, during the sewage treatment process, the biochar saturated with adsorption is difficult to regenerate and is prone to solid waste pollution. Desorption regeneration is a method to break the adsorption equilibrium between the biochar surface and pollutants, and is a new idea for solving the solid waste problem. The surface functional groups of biochar determine its surface acidity and charge, and thus determine the proportion of physical adsorption through electrostatic attraction and hydrogen bonding, affecting the degree of biochar desorption. By regulating the surface functional groups of biochar, that is, the surface charge of biochar, the physical adsorption capacity of biochar can be improved, thereby enhancing the regeneration performance of biochar. Regulating the surface negative charge of biochar and combining it with electrostatic attraction to positively charged cationic dyes can achieve the purpose of selective adsorption. Then, the biochar saturated with adsorption is added to a pH lower than its zero charge (pH pzcWhen in a solution of , the surface functional groups of biochar are protonated under acidic conditions, thus generating electrostatic repulsion with the positively charged pollutants and causing the selectively adsorbed dyes to desorb into the solution. The desorption process of biochar is slow, and it can replace part of the leveling agent and salt to achieve the effect of slow dyeing. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a biochar composite material capable of realizing slow dyeing of acrylic fibers, using waste biomass to prepare the biochar composite material to achieve the resource utilization of waste biomass. Develop a biochar composite material capable of realizing slow dyeing of acrylic fibers and achieve the secondary utilization of adsorbed dyes.

[0006] The technical solution of the present invention:

[0007] A preparation method of a biochar composite material capable of realizing slow dyeing of acrylic fibers, characterized in that: first, the crushed and dried organic waste biomass is pretreated in an alkaline activator solution, after standing and absorbing, it is pre-carbonized at a certain temperature for a period of time and then taken out and dried, the biochar is added to an oxidant and / or acidic activator mixed solution for activation, or the biochar is activated with an oxidant, dried, and finally calcined at high temperature under anaerobic conditions to prepare a biochar composite material capable of realizing slow dyeing of acrylic fibers.

[0008] The present invention uses waste biomass as a raw material, controls the pore and oxygen-containing group numbers of the biochar material through a one-step thermal cracking method, adjusts the specific surface area and surface charge properties of the biochar, and prepares a biochar composite material that can be used for slow dyeing of acrylic fibers. This biochar composite material has adsorption selectivity for cationic dyes in multi-component printing and dyeing waste liquid. By adjusting the pH value, the dyes adsorbed on the biochar composite material can be slowly desorbed in the dye bath, and the dyeing rate of the acrylic fabric can be controlled by using the desorption process to achieve slow dyeing of the acrylic fabric. The amount of leveling agent used can be reduced during the dyeing process, the solution is clear after dyeing, the pollution problem of printing and dyeing wastewater can be avoided, and at the same time, the desorption regeneration of biochar can avoid the solid waste pollution generated by biochar after adsorption use. This material has a simple use process, strong operability, is environmentally friendly, and has good application prospects.

[0009] The organic waste biomass is pretreated with an activator solution, and the mass fraction of the used alkaline activator solution is 5%-20%, the treatment time is 10-24h, and the treatment temperature is 20-50°C. The alkaline activator can destroy the intramolecular and intermolecular forces of some cellulose fiber molecules in the waste biomass, which is beneficial to the formation of more pores during the pre-carbonization process. In addition, the alkaline activator can form a large number of micropores and mesopores by corroding the carbon skeleton of the biochar.

[0010] To prepare the biochar material, the mass fractions of the oxidant and the acidic activator solution are 1-10%, and the stirring and mixing time is 10-15 h. The acidic activator can not only provide acidic conditions for the oxidant, which is beneficial to the oxidation effect of the oxidant, but also improve the carbonization degree of the biochar during the pyrolysis process, corrode the biochar to generate more pores. The oxidant can oxidize the hydroxyl and carbonyl groups on the biochar surface to carboxyl groups, enhancing the electronegativity of the biochar surface.

[0011] The carbonization methods for preparing the biochar material include hydrothermal carbonization, microwave pyrolysis, and high-temperature pyrolysis; the pre-carbonization temperature is 200-500 °C, and the carbonization time is 1-6 h; the carbonization temperature is 500-700 °C, and the carbonization time is 1-6 h. Pre-carbonization enables the biochar to contain hydrogen bonds and carbonyl groups through oxidation reactions, thereby forming hydrogen bonds between and within molecules and improving the thermal stability of the biochar. High-temperature carbonization can further increase the carbonization degree of the biochar, stimulate the action of the acidic activator and the oxidant, and form a porous biochar material rich in oxygen-containing functional groups.

[0012] The organic waste biomass is one of crop or tree processing residues, industrial sludge, food processing residues, and crop straws.

[0013] The alkaline activator used is one of potassium hydroxide and sodium hydroxide.

[0014] The acidic activator used is two or one of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0015] The oxidant used is two or one of hydrogen peroxide, ozone, and nitric acid.

[0016] The biochar composite material that can achieve slow dyeing of acrylic fibers prepared by the described method.

[0017] The prepared biochar composite material can selectively adsorb cationic dyes and achieve slow dyeing of acrylic fibers.

[0018] The biochar composite material saturated with adsorbed dyes, the acidic solution, pure water, and acrylic fabric are added to the dyeing vat together, and the desorption of the dye and the slow dyeing of the acrylic fabric are achieved through a certain dyeing process in a high-temperature and high-pressure dyeing machine.

[0019] The solvent of the acidic solution is acetic acid, and the concentration of the acidic solvent is 2.5%-40% (owf).

[0020] The dyeing bath ratio is 1:40, and the dyeing process is to start dyeing at 75 °C, heat up to 85 °C at 1 °C / min, keep the temperature for dyeing for 15-30 min, then heat up to 100 °C at 1 °C / 2 min, boil the dye for 45-60 min, and finally slowly cool down to 50 °C and take out the machine within 20-40 min.

[0021] In one embodiment of the present invention, the organic waste biomass is pretreated with an activator solution. The mass fraction of the activator solution used is 10%-40%, the treatment time is 360-720 min, and the treatment temperature is 20-150 °C.

[0022] In one embodiment of the present invention, the pre-carbonized biochar material is added to a mixed solution of an oxidant and an acid for soaking and then dried. The mass fraction of the oxidant solution used is 5%-40%, the mass fraction of the acid solution used is 10%-50%, and the soaking time is 1-12 h.

[0023] In one embodiment of the present invention, the carbonization method for preparing the biochar material includes hydrothermal carbonization, microwave pyrolysis, and high-temperature pyrolysis. The pre-carbonization temperature is 200-500 °C, and the carbonization time is 1-6 h. The carbonization temperature is 500-700 °C, and the carbonization time is 1-6 h.

[0024] In one embodiment of the present invention, the organic waste biomass is one of moso bamboo, sewage treatment plant sludge, office waste paper, and crop straw.

[0025] In one embodiment of the present invention, the biochar composite material saturated with adsorbed dyes, an acidic solution, pure water, and acrylic fabric are added to a dyeing vat together, and the desorption of the dyes and the slow dyeing of the acrylic fabric are achieved through a certain dyeing process in a high-temperature and high-pressure dyeing machine.

[0026] Advantages of the present invention: The present invention enriches the pore structure of the biochar through pretreatment with an activator, enriches the oxygen-containing functional groups on the biochar surface through activation with an oxidant and an acid, controls reasonable process conditions, and finally prepares a biochar composite material that can achieve slow dyeing of acrylic. The biochar composite material prepared by the present invention has a large specific surface area and a high selective adsorption efficiency for cationic dyes in multi-component printing and dyeing waste liquid. The slow dyeing of acrylic can be achieved by using the desorption process of the biochar, reducing the problem of solid waste caused by the use of biochar adsorbents. At the same time, the enrichment and utilization of the desorbed dyes are realized, providing a new idea for the reuse of the desorbed dyes. Brief Description of the Drawings

[0027] Figure 1 It is the SEM image of the biochar composite material saturated with adsorbed bamboo powder in an example of the present invention;

[0028] Figure 2 It is the image of the yarn dyed with the desorbed dyes of the biochar composite material saturated with adsorbed bamboo powder in an example of the present invention;

[0029] Figure 3 It is the image of the residual liquid after dyeing with the desorbed dyes of the biochar composite material saturated with adsorbed bamboo powder in an example of the present invention. Detailed Embodiments

[0030] Example 1

[0031] In this example, office waste paper is selected as the raw material for preparation, and the material preparation process is as follows:

[0032] First, the office waste paper is crushed in a crusher, screened through a 200-mesh sieve, dried at 80 °C for 12 h, and then the waste paper powder is immersed in a 10% NaOH solution, stirred and mixed at 35 °C for 12 h, dried, pre-carbonized at 300 °C for 2 h in a nitrogen atmosphere, cooled to room temperature, and the solid product is recovered; the solid product is repeatedly washed with pure water and then filtered, and the product is placed in an oven and dried at 80 °C for 12 h to obtain pre-pyrolyzed bamboo powder biochar; the pre-pyrolyzed bamboo powder biochar is added to 5 wt.% H 2 SO 4 and stirred and mixed with a 10 wt.% H 2 O 2 mixed solution for 12 h of activation by stirring and mixing, dried, and carbonized at 650 °C for 1 h in a nitrogen atmosphere; after cooling to room temperature, it is repeatedly washed with pure water until the pH of the filtrate reaches neutral; the product is placed in an oven and dried at 80 °C for 12 h to obtain a waste paper biochar composite material.

[0033] Example 2

[0034] In this example, sewage treatment plant sludge is selected as the raw material for preparation, and the material preparation process is as follows:

[0035] First, the sludge is dried at 105 °C for 24 h, ground into powder, screened through a 200-mesh sieve, and then the sludge powder is immersed in a 20% NaOH solution, stirred and mixed at 25 °C for 24 h, dried, pre-carbonized at 450 °C for 1 h in a nitrogen atmosphere, cooled to room temperature, and the solid product is recovered; the solid product is repeatedly washed with pure water and then filtered, and the product is placed in an oven and dried at 80 °C for 10 h to obtain pre-pyrolyzed sludge biochar; the pre-pyrolyzed sludge biochar is added to concentrated HNO 3 solution and stirred and mixed for 12 h of activation, dried, and carbonized at 700 °C for 1 h in a nitrogen atmosphere; after cooling to room temperature, it is repeatedly washed with pure water until the pH of the filtrate reaches neutral; the product is placed in an oven and dried at 80 °C for 10 h to obtain a sludge biochar composite material.

[0036] Example 3

[0037] In this example, rice straw is selected as the raw material for preparation, and the material preparation process is as follows:

[0038] First, crush rice straw in a pulverizer, sieve it through a 200-mesh sieve, dry it at 105 °C for 12 h. Then, immerse the rice straw powder in a 10% KOH solution by mass, stir and mix for 12 h, dry it, pre-carbonize it at 350 °C for 2 h in a nitrogen atmosphere, cool it to room temperature, and recover the solid product. Wash the solid product repeatedly with pure water and then filter it. Place the product in an oven and dry it at 105 °C for 12 h to obtain pre-pyrolyzed bamboo powder biochar. Ozonize the pre-pyrolyzed bamboo powder biochar in pure water for 30 min, dry it, and carbonize it at 600 °C for 1 h in a nitrogen atmosphere. After cooling to room temperature, wash it repeatedly with pure water until the pH of the filtrate reaches neutral. Place the product in an oven and dry it at 105 °C for 12 h to obtain a rice straw biochar composite material.

[0039] Example 4

[0040] In this example, moso bamboo is selected as the raw material for preparation, and the material preparation process is as follows:

[0041] First, crush moso bamboo in a pulverizer, sieve it through a 200-mesh sieve, dry it at 80 °C for 30 h. Then, immerse the bamboo powder in a 10% KOH solution by mass, stir and mix for 12 h, dry it, pre-carbonize it at 400 °C for 1 h in a nitrogen atmosphere, cool it to room temperature, and recover the solid product. Wash the solid product repeatedly with pure water and then filter it. Place the product in an oven and dry it at 80 °C for 12 h to obtain pre-pyrolyzed bamboo powder biochar. Add the pre-pyrolyzed bamboo powder biochar to a mixed solution of 10 wt.% H 3 PO 4 and 10 wt.% H 2 O 2 Stir and mix for activation for 12 h, dry it, and carbonize it at 600 °C for 1 h in a nitrogen atmosphere. After cooling to room temperature, wash it repeatedly with pure water until the pH of the filtrate reaches neutral. Place the product in an oven and dry it at 80 °C for 12 h to obtain a bamboo powder biochar composite material, and its surface morphology is as Figure 1 shown.

[0042] Example 5

[0043] Use 0.3 g of the rice straw biochar composite material to selectively adsorb cationic dyes in multi-component printing and dyeing waste liquid, and separate the rice straw biochar composite material adsorbed with dyes by centrifugation. Add the rice straw biochar composite material adsorbed with dyes, 2.5% acetic acid, 30 mL of pure water and 1 g of acrylic fiber cloth into a dyeing vat, and dye in a high-temperature and high-pressure dyeing machine. The dyeing program is to start dyeing at 70 °C, heat up to 85 °C at a rate of 1 °C / min, hold for dyeing for 10 min, then heat up to 95 °C at a rate of 1 °C / 2 min, hold for dyeing for 15 min, heat up to 100 °C at a rate of 1 °C / 4 min, boil for dyeing for 45 min, and finally slowly cool down to 50 °C to take out the machine.

[0044] Example 6

[0045] Use 0.4 g of waste paper biochar composite material to selectively adsorb cationic dyes in multi-component printing and dyeing residual liquid, and centrifuge to separate the waste paper biochar composite material adsorbed with dyes. Add the waste paper biochar composite material adsorbed with dyes, 5% acetic acid, 20 mL of pure water and 1 g of acrylic blanket into the dyeing vat, and dye in a high-temperature and high-pressure dyeing machine. The dyeing procedure is to start dyeing at 70 °C, heat up to 98 °C at a rate of 1 °C every 3 minutes, keep the temperature for dyeing for 60 minutes, and then cool down to 60 °C at a rate of 1 °C per minute to take out the machine.

[0046] Example 7

[0047] Use 0.3 g of sludge biochar composite material to selectively adsorb cationic dyes in multi-component printing and dyeing residual liquid, and centrifuge to separate the sludge biochar composite material adsorbed with dyes. Add the sludge biochar composite material adsorbed with dyes, 10% acetic acid, 30 mL of pure water and 1 g of acrylic knitted wool into the dyeing vat, and dye in a high-temperature and high-pressure dyeing machine. The dyeing procedure is to start dyeing at 70 °C, heat up to 80 °C at a rate of 1 °C per minute, keep the temperature for dyeing for 30 minutes, then heat up to 98 °C at a rate of 1 °C every 3 minutes, keep the temperature for dyeing for 40 minutes, and finally cool down to 60 °C at a rate of 1 °C per minute to take out the machine.

[0048] Example 8

[0049] Prepare a dyeing solution containing 40 mL of 2% cationic blue X-GRL, 2.5%, 8% anhydrous sodium sulfate, and 0.5% leveling agent TAN to dye 1 g of acrylic yarn. The dyeing bath ratio is 1:40. The dyeing procedure is to start dyeing at 75 °C, heat up to 85 °C at a rate of 1 °C per minute, keep the temperature for dyeing for 15 minutes, then heat up to 100 °C at a rate of 1 °C every 2 minutes, boil for 50 minutes, and finally slowly cool down to 50 °C within 25 minutes to take out the machine. The yarn obtained after dyeing is as Figure 2 (left) shown.

[0050] Use 0.3 g of bamboo powder biochar composite material to selectively adsorb cationic dyes in multi-component printing and dyeing residual liquid, and centrifuge to separate the bamboo powder biochar composite material adsorbed with dyes. Add the bamboo powder biochar composite material adsorbed with dyes, 5% acetic acid, 40 mL of pure water and acrylic yarn into the dyeing vat, and carry out desorption regeneration of the biochar composite material and secondary utilization of the desorbed dyes through the same dyeing procedure in a high-temperature and high-pressure dyeing machine. The yarn obtained after dyeing is as Figure 2 (right) shown, and it can be seen that desorption dyeing is feasible.

[0051] After dyeing, the remaining solution in the dyeing vat is as Figure 3 (left) shown. After filtering the remaining solution, the obtained filtrate is clear, as Figure 3 (right) shown.

[0052] Example 9

[0053] Investigate the effect of acetic acid concentration on the slow dyeing of bamboo powder biochar composite:

[0054] Add the bamboo powder biochar composite adsorbed with dye, acrylic yarn and pure water into the dyeing vat, and add 0%, 2.5%, 5%, 10%, 20%, 40% acetic acid respectively. In a high-temperature and high-pressure small prototype, the desorption regeneration of the biochar composite and the secondary utilization of the desorbed dye are carried out through the same dyeing procedure. Use a Datacolor colorimeter to test the K / S value of the acrylic yarn after dyeing and the acrylic yarn dyed with the dye solution. The results are shown in Table 1. It can be found from Table 1 that when the acetic acid concentration is 5%, the K / S value reaches the maximum, and after the acetic acid concentration of 5%, with the increase of the acetic acid concentration, the K / S value no longer increases. Compared with the K / S value of the yarn dyed with the dye, the K / S value of the yarn dyed with the desorbed dye is lower, indicating that the dye adsorbed in the bamboo powder biochar composite cannot be completely desorbed. When no acetic acid is added during desorption dyeing, there is also a dyeing effect on the yarn, indicating that high temperature also has a certain impact on the desorption of the biochar composite.

[0055] Table 1. K / S values of acrylic yarn after dyeing at different acetic acid concentrations

[0056] Dyeing with dye liquor 0％ 2.5％ 5％ 10％ 20％ 40％ K / S value 42.9 17.4 24.1 29.0 28.7 26.0 27.8

Claims

1. Application of a biochar composite material capable of realizing slow dyeing of acrylic fibers in selectively adsorbing cationic dyes to achieve slow dyeing of acrylic fibers, characterized in that, it includes: Adding the biochar composite material saturated with adsorbed dyes, acidic solution, water and acrylic fabric into a dyeing vat, and realizing desorption of the dye and slow dyeing of the acrylic fabric through a dyeing process in a high-temperature and high-pressure dyeing machine; The solvent in the acidic solution is acetic acid, and the concentration of the acetic acid is 5% - 10% owf; The preparation method of the biochar composite material includes the following steps: First, pretreat the crushed and dried organic waste biomass in an alkaline activator solution, let it stand and absorb, then take it out and dry it after pre-carbonization to obtain biochar. Add the biochar to a mixed solution of an oxidant and / or acidic activator for activation, dry it, and finally carry out high-temperature anaerobic calcination and carbonization to prepare a biochar composite material capable of realizing slow dyeing of acrylic fibers; The organic waste biomass is one of residues after tree processing, industrial sludge, food processing residues, and crop straws; The mass fraction of the alkaline activator solution is 5% - 20%; The alkaline activator is one of potassium hydroxide and sodium hydroxide; The pretreatment is carried out by stirring and mixing, the treatment time of the pretreatment is 10 - 24 h, and the treatment temperature is 20 - 50 °C; The conditions of pre-carbonization: the pre-carbonization temperature is 200 - 500 °C, and the carbonization time is 1 - 6 h; The mixed solution of the oxidant and / or acidic activator includes an oxidant and / or acidic activator; The oxidant is two or one of hydrogen peroxide, ozone, and nitric acid; The acidic activator is two or one of hydrochloric acid, sulfuric acid, and phosphoric acid; The conditions of high-temperature anaerobic calcination and carbonization are: the carbonization temperature is 500 - 700 °C, and the carbonization time is 1 - 6 h.

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