An organic dye adsorption material, its preparation method and application

Abstract

The present invention discloses an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid and a preparation method thereof, which comprises the steps of: (1) drying and pulverizing wheat straw to obtain pretreated waste biomass; (2) mixing the waste biomass material with deionized water according to a certain solid-liquid ratio, stirring evenly and then adding it into a reaction kettle for hydrothermal carbonization reaction; (3) after the hydrothermal carbonization reaction is completed, separating the solid-liquid mixture in the inner liner of the reaction kettle by centrifugal filtration, and the obtained liquid is the biomass hydrothermal carbonization waste liquid; (4) adding a corresponding mass of ferric solid into the hydrothermal carbonization waste liquid according to a certain carbon-iron mass ratio, and placing it on a magnetic stirrer for stirring reaction; (5) after the reaction is completed, centrifuging, suction filtering, washing, and freeze-drying, and the obtained product is the organic dye adsorption material. The technical method provided by the present invention has application value in the recycling of resources and the treatment of organic dye wastewater pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection and utilization of waste resources, and particularly relates to an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid and its preparation method and application. Background Art

[0002] Hydrothermal carbonization technology is an emerging method for converting biomass into the main product hydrochar in a unique hydrothermal environment. Hydrochar has a high carbon content and rich surface oxygen-containing functional groups, playing an important role in the fields of environmental protection, energy storage, materials science, etc. The hydrothermal carbonization process is also accompanied by the formation of a liquid-phase by-product (hydrothermal liquor) with high-strength complex components, which poses a challenge to the sustainable hydrothermal carbonization process and is often regarded as wastewater to be treated urgently. Therefore, there is an urgent need to find a green technology for realizing the resource utilization of hydrothermal carbonization waste liquid.

[0003] Coprecipitation is a relatively common process for the formation of organic matter-iron oxide complexes in soil or sediment. Organic matter can form organic matter-iron oxide coprecipitation complexes by means of hydrolysis coprecipitation reaction with Fe(III). During the formation process of the coprecipitation complex, iron oxide will selectively bind organic molecules with high aromaticity and high oxygen content, and the loaded organic matter will also change the original surface properties, reaction activity, stability, etc. of iron oxide, thereby affecting the adsorption performance of iron oxide towards pollutants such as azo dyes and heavy metals. Biomass hydrothermal carbonization waste liquid is rich in a large amount of aromatic substances and organic acids. Based on the formation mechanism of organic matter-iron oxide complexes in natural systems, a hydrothermal carbonization waste liquid-iron oxide complex can be prepared through coprecipitation reaction, storing the organic carbon source in the hydrothermal carbonization waste liquid, and fully exerting the affinity of the loaded organic functional groups for characteristic pollutants to improve its adsorption capacity. Therefore, the present invention prepares a hydrothermal carbonization waste liquid-iron oxide complex by means of the coprecipitation of hydrothermal carbonization waste liquid and Fe(III), in order to develop an environmentally friendly adsorption material that conforms to the concept of "green, low-carbon, sustainable" and is applicable to the treatment of organic dye wastewater pollution, and achieve the green goal of "treating pollution with waste". Summary of the Invention

[0004] The purpose of the present invention is to provide an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid for the treatment of organic dye wastewater pollution.

[0005] In order to achieve the above purpose, the present invention provides a preparation method of an organic dye adsorption material, which comprises the following steps:

[0006] (1) Wheat straw is dried and pulverized to obtain pretreated waste biomass;

[0007] (2) Mix the waste biomass material with deionized water according to a certain solid-liquid ratio. After stirring evenly, add it to a reaction kettle for hydrothermal carbonization reaction;

[0008] (3) After the hydrothermal carbonization reaction is completed, perform solid-liquid separation on the solid-liquid mixture in the reaction kettle. The obtained liquid is the waste liquid of biomass hydrothermal carbonization;

[0009] (4) According to a certain carbon-iron mass ratio, add the corresponding mass of ferric solid to the waste liquid of hydrothermal carbonization and carry out a stirring reaction;

[0010] (5) After the reaction is completed, centrifuge the reactants and discard the supernatant. The product obtained after washing and drying is the organic dye adsorption material.

[0011] Preferably, the solid-liquid ratio in the above step (2) is 1:5 - 15 (g / mL).

[0012] Preferably, for the hydrothermal carbonization reaction in the above step (2), the reaction conditions include: the hydrothermal reaction temperature is 120 - 260 °C. Start timing after the hydrothermal reaction kettle reaches the hydrothermal reaction temperature, and the hydrothermal reaction time is 30 - 120 min.

[0013] Preferably, the carbon-iron mass ratio in the above step (4) is 4 - 8:1.

[0014] Preferably, for the stirring reaction in the above step (4), the reaction conditions include: adjust the pH to 7.0 ± 0.5; under dark conditions, react at a constant temperature of 25 ± 1 °C for 24 h. Among them, adjusting the pH is preferably carried out using NaOH solution and HNO3 solution.

[0015] Preferably, the centrifugation in the above step (5) is carried out at 8000 r / min for 10 min; the washing is carried out 3 times with deionized water; the drying is freeze-drying.

[0016] The present invention also provides an organic dye adsorption material prepared by the preparation method of any one of the above.

[0017] The organic dye adsorption material provided by the present invention can be applied to resource recovery and pollution control, and is particularly useful for the treatment of organic dye wastewater pollution.

[0018] The present invention has the following advantages:

[0019] The raw materials of the organic dye adsorption material provided by the present invention are widely sourced, the preparation method and application cost are low, the adsorption effect on organic dyes in the waste liquid is good, and it has high social and economic value.

[0020] The adsorption material provided by the present invention does not use toxic and harmful substances during the preparation process, and at the same time can realize the resource utilization of biomass hydrothermal carbonization waste liquid, reduce the harm to the environment, and is a green and environmentally friendly method for treating environmental pollution. Description of the Drawings

[0021] Figure 1 Shows the influence of different initial pH values on the adsorption of methylene blue solution by the adsorption material obtained in Example 1.

[0022] Figure 2 Shows the influence results of the adsorption effect of the adsorption material obtained in Example 1 on methylene blue solution under different initial concentration conditions.

[0023] Figure 3 Shows the influence results of the adsorption effect of the adsorption material obtained in Example 2 on methyl orange solution under different initial concentration conditions. Detailed Embodiments

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Note: The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0026] Example 1

[0027] This example provides a preparation method of an organic dye adsorption material, which is as follows:

[0028] (1) Wheat straw is dried and crushed to obtain pretreated waste biomass.

[0029] (2) According to the solid-liquid ratio of 1:7 (g / mL), the waste biomass material is mixed with deionized water, stirred evenly and then added to a reaction kettle for hydrothermal carbonization reaction. The hydrothermal reaction temperature is set at 240 °C, and the timing starts after the hydrothermal reaction kettle reaches the hydrothermal reaction temperature. The hydrothermal reaction time is 60 min.

[0030] (3) After the hydrothermal carbonization reaction is completed, the reaction kettle is immediately taken out and cooled to room temperature in a cold water bath. The solid-liquid mixture in the inner liner of the reaction kettle is separated by centrifugal filtration, and the obtained liquid is the biomass hydrothermal carbonization waste liquid.

[0031] (4) According to the carbon-iron mass ratio of 5:1, add the corresponding mass of ferric nitrate solid to 60 mL of hydrothermal carbonization waste liquid, and place it on a magnetic stirrer for stirring reaction. After the reaction system is adjusted to pH 7.0 by dropwise adding 1 mol / L NaOH solution and 0.1 mol / L HNO3 solution, under dark conditions, react at a constant temperature of 25 ± 1 °C for 24 h.

[0032] (5) After the reaction is completed, centrifuge the reactants at 8000 r / min for 10 min. After centrifugation, pour off the supernatant, add an appropriate amount of deionized water, wash and shake for 1 min, then centrifuge again. Repeat this process 3 times, and freeze-dry the obtained solid phase. The obtained product is an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid and ferric iron under different carbon-iron ratios.

[0033] Among them, except for ferric nitrate, the iron in the carbon-iron mass ratio can also be other ferric iron solids.

[0034] Example 2

[0035] This example also provides a preparation method of an organic dye adsorption material, which is as follows:

[0036] (1) Wheat straw is dried and crushed to obtain pretreated waste biomass.

[0037] (2) According to the solid-liquid ratio of 1:10 (g / mL), mix the waste biomass material with deionized water, stir evenly and add it to the reaction kettle for hydrothermal carbonization reaction. The hydrothermal reaction temperature is set at 240 °C. Start timing after the hydrothermal reaction kettle reaches the hydrothermal reaction temperature, and the hydrothermal reaction time is 90 min.

[0038] (3) After the hydrothermal carbonization reaction is completed, immediately take out the reaction kettle and cool it in a cold water bath to room temperature. Separate the solid-liquid mixture in the inner liner of the reaction kettle by centrifugal filtration, and the obtained liquid is the biomass hydrothermal carbonization waste liquid.

[0039] (4) According to the carbon-iron mass ratio of 5:1, add the corresponding mass of ferric nitrate solid to 60 mL of hydrothermal carbonization waste liquid, and place it on a magnetic stirrer for stirring reaction. After the reaction system is adjusted to pH 7.0 by dropwise adding 1 mol / L NaOH solution and 0.1 mol / L HNO3 solution, under dark conditions, react at a constant temperature of 25 ± 1 °C for 24 h.

[0040] (5) After the reaction is completed, the reactants are centrifuged at 8000 r / min for 10 min. After centrifugation, the supernatant is poured off, an appropriate amount of deionized water is added for washing and shaking for 1 min, and then centrifugation is carried out again. This is repeated 3 times, and the obtained solid phase is freeze-dried. The obtained product is an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid and Fe(III) under different carbon-to-iron ratios.

[0041] Example 3

[0042] This example also provides a preparation method of an organic dye adsorption material, which is as follows:

[0043] (1) Wheat straw is dried and crushed to obtain pretreated waste biomass.

[0044] (2) According to the solid-liquid ratio of 1:7 (g / mL), the waste biomass material is mixed with deionized water, stirred evenly and then added to a reaction kettle for hydrothermal carbonization reaction. The hydrothermal reaction temperature is set at 210 °C, and the timing starts after the hydrothermal reaction kettle reaches the hydrothermal reaction temperature. The hydrothermal reaction time is 60 min.

[0045] (3) After the hydrothermal carbonization reaction is completed, the reaction kettle is immediately taken out and cooled in a cold water bath to room temperature. The solid-liquid mixture in the inner liner of the reaction kettle is separated by centrifugal filtration to obtain the liquid, which is the biomass hydrothermal carbonization waste liquid.

[0046] (4) According to the carbon-to-iron mass ratio of 7.5:1, the corresponding mass of ferric nitrate solid is added to 60 mL of hydrothermal carbonization waste liquid, and the mixture is placed on a magnetic stirrer for stirring reaction. After the pH of the reaction system is adjusted to 7.0 by dropwise adding 1 mol / L NaOH solution and 0.1 mol / L HNO3 solution, the reaction is carried out at a constant temperature of 25 ± 1 °C for 24 h under dark conditions.

[0047] (5) After the reaction is completed, the reactants are centrifuged at 8000 r / min for 10 min. After centrifugation, the supernatant is poured off, an appropriate amount of deionized water is added for washing and shaking for 1 min, and then centrifugation is carried out again. This is repeated 3 times, and the obtained solid phase is freeze-dried. The obtained product is an organic dye adsorption material prepared from biomass hydrothermal carbonization waste liquid and Fe(III) under different carbon-to-iron ratios.

[0048] Experimental Example 1 Determination of the adsorption effect of the organic dye adsorption material on methylene blue

[0049] 1. Determine the influence of different initial solution pH values on adsorption

[0050] According to the dosing ratio of 0.5 g / L, the organic dye adsorption material obtained in Example 1 was added to methylene blue solutions with a volume of 30 mL, a concentration of 30 mg / L, and pH values of 3, 5, 7, 9, and 11 respectively. The initial pH of the solution was adjusted using NaOH solution and HCl solution, and the mixture was placed on a constant temperature shaker at 25 ± 1 °C and oscillated for 3 h. After the reaction, centrifugal separation was carried out, and the absorbance of the supernatant at a wavelength of 664 nm was measured.

[0051] The influence results of different initial pH values on the adsorption of methylene blue solution by the adsorption material are as Figure 1 shown. It can be seen that the adsorption capacity of the adsorption material for methylene blue increases with the increase of pH. Analysis shows that as the pH value of the solution increases, the chromogenic group of the cationic dye methylene blue is positively charged after ionization in water, and the rich oxygen-containing functional groups on the surface of the adsorption material have an increased degree of dissociation of H + , increasing the electronegativity of the adsorption material. The adsorption material and methylene blue are quickly combined through electrostatic attraction, thereby completing the adsorption of the organic dye.

[0052] 2. Determine the influence of different initial solution concentrations on adsorption

[0053] According to the dosing ratio of 0.5 g / L, the organic dye adsorption material obtained in Example 1 was added to methylene blue solutions with a volume of 30 mL and concentrations of 10, 20, 30, 40, and 50 mg / L respectively. After adjusting the pH to 7, the mixture was placed on a constant temperature shaker at 25 ± 1 °C and oscillated for 3 h. After the reaction, centrifugal separation was carried out, and the absorbance of the supernatant at a wavelength of 664 nm was measured.

[0054] The influence results of the adsorption effect of the adsorption material on methylene blue solution under different initial concentration conditions are shown in Figure 2 the figure. It can be seen that as the initial concentration of methylene blue increases from 10 mg / L to 50 mg / L, the adsorption capacity of the adsorption material for methylene blue increases from 18.38 to 55.60 mg / g, and when the initial concentration is higher than 40 mg / L, the improvement of its adsorption effect is not significant and tends to be flat.

[0055] Experimental Example 2 Determination of the adsorption effect of the organic dye adsorption material on methyl orange

[0056] According to the dosing ratio of 0.5 g / L, the organic dye adsorption material obtained in Example 2 was added to methyl orange solutions with a volume of 30 mL and concentrations of 5, 10, 15, 20, 25, and 35 mg / L respectively. After adjusting the pH to 7, the mixture was placed on a constant temperature shaker at 25 ± 1 °C and oscillated for 3 h. After the reaction, centrifugal separation was carried out, and the absorbance of the supernatant at a wavelength of 463 nm was measured.

[0057] The influence results of the adsorption effect of the adsorption material on methyl orange solution under different initial concentration conditions are shown inFigure 3 As shown, it can be seen that as the initial concentration of methyl orange increases from 5 mg / L to 35 mg / L, the adsorption capacity of the adsorbent for methyl orange increases from 7.91 to 31.49 mg / g. And when the initial concentration is higher than 20 mg / L, the improvement of its adsorption effect is not significant and tends to be flat.

[0058] In summary, the present invention provides an organic dye adsorbent and its preparation method. The technical solution provided can recycle waste resources, and the prepared adsorbent can also effectively adsorb organic dyes, having application value in the treatment of organic dye wastewater pollution.

[0059] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art read the above content, various modifications and substitutions of the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A preparation method of an organic dye adsorption material, characterized in that It includes the following steps: (1) Wheat straw is dried and crushed to obtain pretreated waste biomass; (2) The waste biomass material is mixed with deionized water according to a certain solid-liquid ratio, and after stirring evenly, it is added to a reaction kettle for hydrothermal carbonization reaction; (3) After the hydrothermal carbonization reaction is completed, the solid-liquid mixture in the reaction kettle is separated into solid and liquid, and the obtained liquid is the hydrothermal carbonization waste liquid of biomass; (4) According to a certain carbon-iron mass ratio, the corresponding mass of ferric solid is added to the hydrothermal carbonization waste liquid and stirred for reaction; (5) After the reaction is completed, the reactants are centrifuged and the supernatant is discarded. The product obtained after washing and drying is the organic dye adsorption material; Among them, the ferric solid is selected from ferric nitrate.

2. The preparation method according to claim 1, characterized in that, The solid-liquid ratio in the step (2) is 1:5 - 15 g / mL.

3. The preparation method according to claim 1, characterized in that, For the hydrothermal carbonization reaction in the step (2), the reaction conditions include: the hydrothermal reaction temperature is 120 - 260 °C, and the timing starts after the hydrothermal reaction kettle reaches the hydrothermal reaction temperature, and the hydrothermal reaction time is 30 - 120 min.

4. The preparation method according to claim 1, characterized in that, The carbon-iron mass ratio in the step (4) is 4 - 8:

1.

5. The preparation method according to claim 1, characterized in that, For the stirring reaction in the step (4), the reaction conditions include: adjusting the pH to 7.0 ± 0.5; under dark conditions, reacting at a constant temperature of 25 ± 1 °C for 24 h.

6. The preparation method according to claim 5, characterized in that, The pH adjustment is carried out by using NaOH solution and HNO3 solution.

7. The preparation method according to claim 1, wherein The centrifugation in the step (5) is centrifugation at 8000 r / min for 10 min; the washing is washing 3 times with deionized water; The drying is freeze-drying.

8. The organic dye adsorption material prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the organic dye adsorption material according to claim 8 in resource recovery and pollution control.

10. The application according to claim 9, wherein The pollution includes organic dye wastewater pollution.

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