Coking wastewater purifying agent as well as preparation method and application thereof

Abstract

The invention discloses a coking wastewater purifying agent and a preparation method and application thereof, the purifying agent is prepared from the following raw materials in parts by weight: 20-25 parts of activated carbon, 18-25 parts of a compound, 4-9 parts of polyacrylamide, 1-5 parts of a surfactant and 60-90 parts of water, and the compound is prepared by compounding pear residues and modified shell carbon. The method is used for solving the technical problem that the coking wastewater cannot reach the discharge standard.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a coking wastewater purifier and a preparation method and application thereof. Background Art

[0002] Coking wastewater is wastewater with a large amount of aromatic compounds and heterocyclic compounds produced in the process of coal-to-coke, coal gas purification and coking product recovery. It is a high-concentration, difficult-to-degrade organic wastewater. Domestic coking wastewater is discharged after being treated by biological methods. This technology is one of the common processes in the coking industry.

[0003] At present, after biochemical treatment of coking wastewater, most of the organic matter is degraded, but the COD, color and turbidity indicators still cannot meet the national emission standards and need further treatment. The treatment methods mostly use the addition of a single agent or decolorizer for purification. This method has the disadvantages of large amount of agent added, low removal efficiency and poor water quality color, which usually cannot meet the national emission standards. Summary of the invention

[0004] The invention provides a coking wastewater purifier and a preparation method and application thereof, which are used to solve the technical problem that the existing coking wastewater cannot meet the national discharge standard.

[0005] In view of this, the present invention provides a coking wastewater purifier, comprising the following raw materials in parts by weight: 20-25 parts of activated carbon, 18-25 parts of a composite, 4-9 parts of polyacrylamide, 1-5 parts of a surfactant, and 60-90 parts of water, wherein the composite is a compound of pear residue and modified fruit shell carbon.

[0006] Optionally, the composite is prepared by the following method:

[0007] A1: crushing the modified fruit shell carbon, sieving, and obtaining crushed modified fruit shell carbon;

[0008] A2: Wash, dry, crush, sieve, put into ethanol solution, mix well, and obtain a mixed solution;

[0009] A3: Put the crushed modified fruit shell carbon into the mixed liquid, mix evenly, heat to increase temperature, react, cool down, centrifuge, wash, and dry to obtain a composite.

[0010] Furthermore, the composite is prepared by the following method:

[0011] A1: crush the modified fruit shell carbon, and pass it through a 80-120 mesh sieve to obtain the crushed modified fruit shell carbon;

[0012] A2: Wash the pear residue, dry it, crush it, pass it through a 80-120 mesh sieve, put it into an ethanol solution, mix it evenly, and obtain a mixed solution;

[0013] A3: Add the crushed modified fruit shell carbon into the mixed solution, mix evenly, heat to 40-60°C, react for 1-2h, cool to 22±3°C, centrifuge, wash with water 3-5 times, and dry to obtain a composite;

[0014] Wherein, in step A2, the amount of ethanol solution added to every 1g of pear residue is 3-5mL, and the mass fraction of the ethanol solution is 40%.

[0015] Optionally, the weight ratio of the pear residue to the modified fruit shell carbon is (0.4-0.7):1.

[0016] Optionally, the fruit shell carbon is a mixture of carbonized apricot shells and walnut shells, and the weight ratio of apricot shells to walnut shells is 1:1.

[0017] Optionally, the modified fruit shell carbon is prepared by the following method:

[0018] B1: Wash, crush, sieve and evenly mix apricot shells and walnut shells to obtain husks;

[0019] B2: heating the fruit shell under the protection of an inert gas to carbonize it, and cooling it to obtain fruit shell carbon;

[0020] B3: Add an activator to the fruit shell carbon, grind and mix, heat again, react, cool, wash, and dry to obtain modified fruit shell carbon.

[0021] Furthermore, the modified fruit shell carbon is prepared by the following method:

[0022] B1: Wash and crush apricot shells and walnut shells, pass through a 100-120 mesh sieve, and mix well to obtain husks;

[0023] B2: Heat the fruit shell to 450-650°C under the protection of inert gas nitrogen, carbonize for 2-3 hours, and cool to 22±3°C to obtain fruit shell carbon;

[0024] B3: Add activator to the fruit shell carbon, grind and mix, heat again to 750-850℃, react for 1-3h, cool to 22±3℃, wash with water 3-5 times, dry to obtain modified fruit shell carbon;

[0025] The activator is potassium hydroxide, and the weight ratio of the fruit shell carbon to potassium hydroxide is 1:(0.4-0.6).

[0026] Optionally, the pear residue is further subjected to the following modification treatment before use: the pear residue is placed in an ethylene glycol solution, α-hydroxy iron oxide is added, mixed evenly, heated and reacted, and after the reaction is completed, the solid matter is taken out, cooled, washed, and dried to obtain modified pear residue.

[0027] Furthermore, the pear residue is subjected to the following modification treatment before use: the pear residue is placed in an ethylene glycol solution, α-iron hydroxide is added, mixed evenly, heated to 100-140° C., reacted for 5-7 hours, after the reaction is completed, the solid is taken out, cooled to 22±3° C., washed with ethanol for 3-5 times, and dried to obtain modified pear residue;

[0028] The amount of ethylene glycol solution added to 1g of pear residue is 5-7mL, the mass fraction of the ethylene glycol solution is 12.5%, and the weight ratio of pear residue to α-iron hydroxide is 1:(0.1-0.2).

[0029] Optionally, the pear residue is pretreated by the following method before use: the pear residue is washed, put into a hydrochloric acid solution, mixed evenly, reacted in a water bath, and after the reaction is completed, the solid matter is taken out, washed, and dried to obtain the pretreated pear residue.

[0030] Furthermore, the pear residue is pretreated by the following method before use: the pear residue is washed, put into a hydrochloric acid solution, mixed evenly, and reacted in a water bath at a temperature of 40-60° C. for 1-2 hours. After the reaction is completed, the solid is taken out, washed with water for 3-5 times, and dried to obtain the pretreated pear residue;

[0031] The amount of hydrochloric acid solution added to 1g of pear residue is 2-4mL, and the mass fraction of the hydrochloric acid solution is 40%.

[0032] A method for preparing a coking wastewater purifier comprises the following steps: putting activated carbon, a composite, polyacrylamide and a surfactant into water, and mixing them evenly to obtain the purifier.

[0033] The invention discloses an application of a coking wastewater purifier, comprising the following steps: adding the purifier into the coking wastewater to be treated, mixing evenly, aerating, standing, filtering, and obtaining the treated coking wastewater.

[0034] Optionally, the added amount of the purifier is 0.4-0.7wt% of the coking wastewater to be treated.

[0035] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0036] 1. In this application, activated carbon, composites, and polyacrylamide are used as the main raw materials of the purifier. Among them, the activated carbon is loose and porous, has excellent adsorption, and can adsorb COD and pigment substances in the coking wastewater. Polyacrylamide can be used as a flocculant, which can form precipitation with pollutants and pigment substances in the coking wastewater, and settle them, thereby removing them;

[0037] The composite is made of pear residue and modified fruit shell carbon. The use of pear residue not only realizes waste utilization and saves resources, but also the surface of pear residue has a porous structure, which provides a large number of adsorption sites and can adsorb COD, pigments, pollutants and other substances in coking wastewater. The use of modified fruit shell carbon also realizes waste utilization and saves resources. In addition, fruit shell carbon also has a high specific surface area and a developed pore structure, and has excellent adsorption capacity. After the fruit shell carbon is modified, its adsorption performance is further improved; pear residue and modified fruit shell carbon are compounded into a composite. The pore structure of pear residue is suitable for adsorbing large molecular organic matter, and the pore structure of modified fruit shell carbon is suitable for adsorbing small molecular organic matter. The total specific surface area and pore structure of the composite are increased, which further enhances the adsorption performance and is more conducive to the removal of COD, color and turbidity.

[0038] 2. The present application also uses ɑ-hydroxy ferric oxide to modify the pear residue. ɑ-hydroxy ferric oxide is a material with high adsorption performance. After the introduction of ɑ-hydroxy ferric oxide on the surface of the pear residue, the specific surface area and surface active sites of the pear residue can be increased. Through the synergistic effect between the two, the adsorption capacity of COD, pigments, pollutants and other substances is further enhanced, thereby improving the treatment effect of coking wastewater.

[0039] 3. The present application also uses hydrochloric acid solution to pretreat the pear residue, which changes the chemical properties of the pear residue surface, increases the active sites on its surface, and can also introduce acidic functional groups on the pear residue surface, thereby further improving the adsorption of the pear residue and improving the treatment effect on coking wastewater, making it easier for coking wastewater to meet emission standards. DETAILED DESCRIPTION

[0040] In order to make the technical scheme of the present invention better understood by the personnel of the technical field, the technical scheme in the embodiment of the present invention is clearly and completely described below. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. Based on the embodiment in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be prepared by existing methods.

[0041] Preparation Example

[0042] Preparation Example 1

[0043] A modified fruit shell carbon is prepared by the following method:

[0044] B1: Wash 2 kg of apricot shells and 2 kg of walnut shells, crush them, pass them through a 110-mesh sieve, and mix them evenly to obtain fruit shells;

[0045] B2: The fruit shell is heated to 550°C under the protection of inert gas nitrogen, carbonized for 2.5 hours, and then cooled to 25°C to obtain fruit shell carbon;

[0046] B3: Add 2 kg of potassium hydroxide to the fruit shell carbon, grind and mix, heat again to 800°C, react for 2 hours, cool to 25°C, and dry to obtain modified fruit shell carbon.

[0047] Preparation Example 2

[0048] A composite is prepared by the following method:

[0049] A1: 2 kg of the modified fruit shell carbon prepared in Preparation Example 1 was crushed and passed through a 100-mesh sieve to obtain crushed modified fruit shell carbon;

[0050] A2: 0.8 kg of pear residue was washed, dried, crushed, passed through a 100-mesh sieve, put into a 40% by mass ethanol solution, and mixed evenly to obtain a mixed solution; wherein the amount of ethanol solution added to 1 g of pear residue was 4 mL;

[0051] A3: Add the crushed modified fruit shell carbon into the mixed solution, mix evenly, heat to 50°C, react for 1.5 hours, cool to 25°C, centrifuge, wash with water 5 times, and dry to obtain a composite.

[0052] Preparation Example 3

[0053] A composite material, which is different from Preparation Example 2 in that the amount of pear residue added is different, and the amount of pear residue added in Preparation Example 3 is 1.1 kg.

[0054] Preparation Example 4

[0055] A composite material, which is different from Preparation Example 2 in that the amount of pear residue added is different, and the amount of pear residue added in Preparation Example 4 is 1.4 kg.

[0056] Preparation Example 5

[0057] A composite material, which is different from Preparation Example 2 in that the amount of pear residue added is different, and the amount of pear residue added in Preparation Example 5 is 0.5 kg.

[0058] Preparation Example 6

[0059] A composite material, which is different from Preparation Example 2 in that the amount of pear residue added is different, and the amount of pear residue added in Preparation Example 6 is 3 kg.

[0060] Example

[0061] Example 1

[0062] A coking wastewater purifier, the raw material ratio of which is shown in Table 1.

[0063] A method for preparing a coking wastewater purifier comprises the following steps:

[0064] Activated carbon, the composite prepared in Preparation Example 2, polyacrylamide, and a surfactant were put into water and mixed evenly to obtain a purifier.

[0065] Embodiment 2-8

[0066] A coking wastewater purifier is different from Example 1 in that the raw material ratio of the purifier is different. The raw material ratio is shown in Table 1.

[0067] Table 1 Weight of each raw material of the purifier (kg)

[0068]

[0069]

[0070] Examples 9-12

[0071] A coking wastewater purifier is provided, which is different from Example 8 in that the sources of the composite are different, and the composites in Examples 9-12 are prepared by Preparation Examples 3-6, respectively.

[0072] Embodiment 13

[0073] A coking wastewater purifier, which differs from Example 9 in that the pear residue in the composite is further subjected to the following modification treatment before use: the pear residue is placed in an ethylene glycol solution with a mass fraction of 12.5%, α-hydroxy iron oxide is added, mixed evenly, heated to 120°C, reacted for 6 hours, and after the reaction is completed, the solid matter is taken out, cooled to 25°C, washed with ethanol 5 times, and dried to obtain modified pear residue; wherein the amount of ethylene glycol solution added to every 1g of pear residue is 6mL, and the weight ratio of pear residue to α-hydroxy iron oxide is 1:0.15.

[0074] Embodiment 14

[0075] A coking wastewater purifier, which differs from Example 13 in that the pear residue in the composite is also pretreated as follows before use: the pear residue is washed, put into a hydrochloric acid solution with a mass fraction of 40%, mixed evenly, and reacted in a water bath at a temperature of 50°C for 1.5 hours. After the reaction is completed, the solid matter is taken out, washed with water 5 times, and dried to obtain the pretreated pear residue; wherein the amount of hydrochloric acid solution added to every 1g of pear residue is 3mL.

[0076] Comparative Example

[0077] Comparative Example 1

[0078] A coking wastewater purifier is different from Example 1 in that no composite material is added to the raw materials of the purifier.

[0079] Comparative Example 2

[0080] A coking wastewater purifier, which differs from Example 1 in that the modified nutshell carbon in the composite is replaced by nutshell carbon in equal amounts.

[0081] Comparative Example 3

[0082] A coking wastewater purifier, which differs from Example 1 in that the modified fruit shell carbon in the composite is replaced by pear residue in equal amounts.

[0083] Comparative Example 4

[0084] A coking wastewater purifier, which differs from Example 1 in that an equal amount of pear residue in the composite is replaced by modified fruit shell carbon.

[0085] Application Examples

[0086] Application Example 1

[0087] An application of a coking wastewater purifier comprises the following steps:

[0088] The purifier prepared in Example 1 was added to the coking wastewater to be treated, mixed evenly, aerated, and allowed to stand to obtain treated coking wastewater; wherein the amount of the purifier added was 0.5wt% of the coking wastewater to be treated.

[0089] Application Example 2-14

[0090] The difference between Application Example 2-14 and Application Example 1 is that the sources of the purifiers are different, and the purifiers in Application Examples 2-14 are prepared using Examples 2-14, respectively.

[0091] Application Comparative Examples 1-4

[0092] The difference between Application Comparative Examples 1-4 and Application Example 1 is that the sources of the purifiers are different, and the purifiers in Application Comparative Examples 1-4 are prepared using Comparative Examples 1-4, respectively.

[0093] Performance test

[0094] The coking wastewater treated in Example 1-14 and Comparative Example 1-4 was measured:

[0095] COD: The COD in the treated coking wastewater was measured according to HJ828-2017 "Determination of Chemical Oxygen Demand of Water Quality - Dichromate Method". The test results are shown in Table 2.

[0096] Chroma: The chroma of the treated coking wastewater was measured in accordance with GB / T11903-89 “Determination of Chroma of Water Quality”. The test results are shown in Table 2.

[0097] Turbidity: The turbidity of the treated coking wastewater was measured according to GB / T13200-91 "Determination of turbidity of water quality". The test results are shown in Table 2.

[0098] Before treatment, the COD content in the coking wastewater was 2300 mg / L, the chromaticity was 120 times, and the turbidity was 150 NTU.

[0099] Table 2 Test results

[0100]

[0101]

[0102] As can be seen from Table 2, the coking wastewater purifier of the present application, through the joint action of various raw materials, significantly reduces the COD, chromaticity and turbidity in the coking wastewater, among which the COD removal rate is 95.9-99.5%, the chromaticity removal rate is 80.7-85.4%, and the turbidity removal rate is 86.7-91.6%.

[0103] Combining Application Example 1 and Application Comparative Examples 1-4, it can be seen that the COD removal rate in the treated coking wastewater in the application example is 96.1%, the chromaticity removal rate is 81.1%, and the turbidity removal rate is 87.6%, which are better than Application Comparative Examples 1-4, indicating that it is more appropriate to compound the composite with pear residue and modified fruit shell carbon, which not only realizes waste utilization and saves resources, but also pear residue and modified fruit shell carbon have certain adsorption properties. The pore structure of pear residue and modified fruit shell carbon are compounded into a composite, the pore structure of pear residue is suitable for adsorbing large molecular organic matter, the pore structure of modified fruit shell carbon is suitable for adsorbing small molecular organic matter, and the total specific surface area and pore structure of the composite are increased, that is, the adsorption performance is further enhanced, which is more conducive to the removal of COD, chromaticity and turbidity.

[0104] Combined with Application Examples 1-3, it can be seen that the COD removal rate in the treated coking wastewater in Application Example 2 is 96.6%, the chroma removal rate is 81.8%, and the turbidity removal rate is 88.2%, which are better than other application examples, indicating that the amount of the composite added in Application Example 2 is more appropriate, and can better improve the removal of COD, chroma, and turbidity. When the amount of the composite added is too little, it will not have a better adsorption effect, and the purification effect on the coking wastewater will not be optimal; when the amount of the composite added is too much, it will lead to saturation of the composite adsorption sites, resulting in the inability of the excess composite to effectively adsorb pollutants, but will increase the difficulty of treating the coking wastewater, and the excess composite may release some other substances, which will affect the water quality of the coking wastewater.

[0105] Combining Application Example 2 with Application Examples 4-5, it can be seen that the removal rate of COD in the treated coking wastewater in Application Example 4 is 97.3%, the removal rate of chroma is 82.3%, and the removal rate of turbidity is 88.8%, which is better than other application examples, indicating that the amount of activated carbon added in Application Example 4 is more appropriate and can improve the purification effect of coking wastewater. When the amount of activated carbon added is too little, it cannot achieve a better adsorption effect; when the amount of activated carbon added is too much, the adsorption sites of the activated carbon are saturated, and the excess activated carbon cannot achieve adsorption, which will also cause a waste of raw materials.

[0106] Combining Application Example 4 and Application Examples 6-7, it can be seen that the COD removal rate in the treated coking wastewater in Application Example 7 is 97.8%, the chromaticity removal rate is 82.9%, and the turbidity removal rate is 89.6%, which are better than other application examples, indicating that the addition amount of polyacrylamide in Application Example 7 is more appropriate and has a better flocculation effect.

[0107] Combining Application Examples 7 and 8, it can be seen that the influence of the addition amount of surfactant and water on coking wastewater is not significant when it varies within a certain range.

[0108] Combining Application Example 7 and Application Examples 9-12, it can be seen that the COD removal rate in the treated coking wastewater in Application Example 9 is 98.3%, the chromaticity removal rate is 83.8%, and the turbidity removal rate is 90.5%, which are better than other application examples, indicating that the composite prepared by Preparation Example 3 is more suitable. Too much or too little addition of pear residue cannot achieve a better synergistic effect with the modified fruit shell carbon. The addition amount of pear residue in Preparation Example 3 is better, which can make the composite have a better adsorption effect.

[0109] Combining Application Examples 9 and 13, it can be seen that the COD removal rate in the coking wastewater after treatment in Application Example 13 is 99.2%, the chromaticity removal rate is 84.9%, and the turbidity removal rate is 91.0%, which are better than those in Application Example 9, indicating that the pear residue is more suitable after modification. After the introduction of α-hydroxy iron oxide on the surface of the pear residue, the specific surface area and surface active sites of the pear residue can be increased. Through the synergistic effect between the two, the adsorption capacity for COD, pigments and other substances is further enhanced, thereby improving the treatment effect of coking wastewater.

[0110] Combining Application Example 13 and Application Example 14, it can be seen that the COD removal rate in the coking wastewater after treatment in Application Example 14 is 99.5%, the chroma removal rate is 85.4%, and the turbidity removal rate is 91.6%, which are better than Application Example 13, indicating that it is more appropriate to pretreat the pear residue before use. Pretreating the pear residue with hydrochloric acid solution can change the chemical properties of the pear residue surface, increase the active sites on its surface, and introduce acidic functional groups on the pear residue surface, thereby further improving the adsorption of the pear residue and improving the treatment effect on the coking wastewater, so that the coking wastewater can meet the emission standards.

[0111] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coking wastewater purifier, characterized in that: The invention comprises the following raw materials in parts by weight: 20-25 parts of activated carbon, 18-25 parts of composite materials, 4-9 parts of polyacrylamide, 1-5 parts of surfactant and 60-90 parts of water, wherein the composite materials are compounded from pear residue and modified fruit shell carbon.

2. The coking wastewater purifier according to claim 1, characterized in that: The composite was prepared by the following method: A1: crushing the modified fruit shell carbon, sieving, and obtaining crushed modified fruit shell carbon; A2: Wash, dry, crush, sieve, put into ethanol solution, mix well, and obtain a mixed solution; A3: Put the crushed modified fruit shell carbon into the mixed liquid, mix evenly, heat to increase temperature, react, cool down, centrifuge, wash, and dry to obtain a composite.

3. The coking wastewater purifier according to claim 2, characterized in that: The weight ratio of the pear residue to the modified fruit shell carbon is (0.4-0.7):

1.

4. The coking wastewater purifier according to claim 2, characterized in that: The fruit shell carbon is a mixture of carbonized apricot shells and walnut shells, and the weight ratio of the apricot shells to the walnut shells is 1:

1.

5. The coking wastewater purifier according to claim 2, characterized in that: The modified fruit shell carbon is prepared by the following method: B1: Wash, crush, sieve and evenly mix apricot shells and walnut shells to obtain husks; B2: The fruit shell is heated and cooled under the protection of an inert gas to carbonize the fruit shell to obtain fruit shell carbon; B3: Add an activator to the fruit shell carbon, grind and mix, heat again, react, cool, wash, and dry to obtain modified fruit shell carbon.

6. The coking wastewater purifier according to claim 2, characterized in that: The pear residue is also subjected to the following modification treatment before use: the pear residue is placed in an ethylene glycol solution, α-hydroxy iron oxide is added, mixed evenly, heated and reacted, and after the reaction is completed, the solid matter is taken out, cooled, washed, and dried to obtain modified pear residue.

7. The coking wastewater purifier according to claim 6, characterized in that: The pear residue is pretreated by the following method before use: the pear residue is washed, put into a hydrochloric acid solution, mixed evenly, reacted in a water bath, and after the reaction is completed, the solid matter is taken out, washed, and dried to obtain the pretreated pear residue.

8. A method for preparing a coking wastewater purifier according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: putting activated carbon, a composite material, polyacrylamide and a surfactant into water, and mixing them evenly to obtain a purifier.

9. The use of a coking wastewater purifier according to claim 8, characterized in that: The method comprises the following steps: adding a purifying agent into the coking wastewater to be treated, mixing evenly, aerating, standing, filtering, and obtaining the treated coking wastewater.

10. The use of a coking wastewater purifier according to claim 9, characterized in that: The added amount of the purifier is 0.4-0.7wt% of the coking wastewater to be treated.

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