Preparation method and application of activated carbon based on ferrous-loaded petroleum coke gasification ash

Abstract

The application provides a preparation method of activated carbon based on ferrous-loaded petroleum coke gasification ash, which comprises the following steps: crushing, grinding and sieving petroleum coke gasification ash to obtain sieved petroleum coke gasification ash; washing the sieved petroleum coke gasification ash with alkali, water, acid and water at 80-90 DEG C to obtain activated and purified activated carbon; adding a surfactant aqueous solution, an immersion aid aqueous solution and a ferrous salt aqueous solution to the activated carbon, stirring and mixing, ultrasonic treatment, drying and roasting under inert gas to obtain impregnated and roasted activated carbon; and mixing the activated carbon with a sesbania gum solution, drying and obtaining the activated carbon based on ferrous-loaded petroleum coke gasification ash. The application is also provided, which is used for removing COD in metallurgical wastewater. The activated carbon based on ferrous-loaded petroleum coke gasification ash prepared by the method has the characteristics of simple operation, short process, long service life and the like, and solves the problems of long process flow, easy saturation of activated carbon and high operation cost in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of activated carbon preparation, and in particular relates to a preparation method and application of activated carbon based on ferrous iron loaded petroleum coke gasification ash. Background Art

[0002] Petroleum coke gasification ash is a waste product produced during the petroleum coke gasification process. This residue remains after the carbon in the petroleum coke has been fully utilized. While it still contains abundant carbon resources, it also accumulates valuable heavy metals from crude oil, limiting its downstream applications. Currently, petroleum coke gasification ash is primarily disposed of as a solid waste, primarily as a fuel. The combustion process produces significant amounts of greenhouse gases, while also underutilizing this valuable resource. Therefore, rationally recovering this valuable resource, effectively utilizing carbon, and maximizing the value of petroleum coke resources have significant environmental and social benefits.

[0003] Extraction is currently a key method for the selective separation and purification of valuable metals in the hydrometallurgical industry. Extractants and diluents used in the hydrometallurgical process dissolve to varying degrees in the aqueous phase, causing elevated COD levels in the extract wastewater. In the metallurgical extraction industry, COD levels can reach as high as 500-1000 mg / L. Furthermore, the hydrometallurgical process introduces large amounts of acids, alkalis, and salts, resulting in high-salt, high-COD wastewater, making biochemical degradation difficult. The industry's pain point in extractive hydrometallurgy is the difficulty of treating wastewater with excessively high COD levels.

[0004] Activated carbon has a well-developed pore structure and exhibits strong physical adsorption of pollutants in aqueous solutions. However, activated carbon only acts as a locational migration agent for COD and lacks degradation. Therefore, multi-stage adsorption is often used to remove COD, which is prone to saturation. After saturation, the activated carbon needs to be regenerated, resulting in high operating costs. Therefore, the COD adsorption efficiency of conventional commercial activated carbon is insufficient to meet wastewater treatment requirements.

[0005] Advanced oxidation technology (AOT) is widely used in wastewater COD treatment due to its strong oxidizing effect. However, further improving COD degradation requires increasing the dosage of oxidant. Furthermore, the process produces large amounts of iron sludge that is difficult to filter, resulting in high operating and treatment costs. Therefore, the degradation and removal of organic matter is often achieved through the tandem use of AO and activated carbon adsorption, which results in a lengthy process and high operating costs.

[0006] Therefore, in response to the above problems, developing resource utilization methods for petroleum coke gasification slag and applying it to improve the removal of COD in metallurgical extraction wastewater, realizing the effective utilization of resources and achieving the goal of treating waste with waste, has important economic and social significance. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a method for preparing activated carbon based on ferrous iron-loaded petroleum coke gasification ash and its application. The activated carbon based on ferrous iron-loaded petroleum coke gasification ash prepared by this method has the characteristics of simple process operation, short process flow and long service life of activated carbon for removing COD, which solves the problems in the prior art of long process flow, easy saturation of activated carbon and high operating cost of activated carbon in series removal of COD using advanced oxidation technology.

[0008] To solve the above technical problems, the present invention adopts a technical solution: a method for preparing activated carbon based on ferrous metal-loaded petroleum coke gasification ash, the method comprising:

[0009] S1. Crushing, grinding, and sieving petroleum coke gasification ash to obtain sieved petroleum coke gasification ash;

[0010] S2. At a temperature of 80° C. to 90° C., the sieved petroleum coke gasification ash obtained in S1 is sequentially subjected to alkali washing, water washing, acid washing, and water washing to obtain activated and purified activated carbon;

[0011] S3, adding a surfactant aqueous solution, a soaking aid aqueous solution, and a ferrous salt aqueous solution to the activated carbon obtained in S2, stirring and mixing, and then impregnating, and then ultrasonically treating, and drying and calcining under the protection of an inert gas to obtain impregnated and calcined activated carbon;

[0012] S4. The activated carbon obtained in S3 and the impregnated and calcined activated carbon is mixed with the sesbania gum solution, and dried to obtain activated carbon based on ferrous iron loaded petroleum coke gasification ash.

[0013] Preferably, the particle size of the sieved petroleum coke gasification ash in S1 is less than 50 μm.

[0014] Preferably, the mass fraction of the surfactant in the surfactant aqueous solution in S3 is 0.5%, and the mass fraction of the immersion aid in the immersion aid aqueous solution is 0.5%; the concentration of the ferrous salt aqueous solution is 10 g / L; the usage ratio of the activated carbon after activation and purification, the surfactant aqueous solution, the immersion aid aqueous solution and the ferrous salt aqueous solution is 100 g: (10-30) mL: (20-50) mL: (60-70) mL.

[0015] Preferably, the surfactant is sodium naphthalenesulfonate, the leaching aid is sodium citrate, and the ferrous salt of the ferrous salt aqueous solution is ferrous sulfate.

[0016] The surfactant in the present invention can also be one or a combination of two of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium naphthalene sulfonate, and sodium lignin sulfonate;

[0017] The soaking aid in the present invention can also be one or a combination of two of sodium citrate, sodium tartrate, and sodium lactate;

[0018] The ferrous salt in the present invention may also be ferrous sulfate, ferrous chloride, or a combination of both.

[0019] Preferably, the stirring, mixing and impregnation time in S3 is 80 minutes, and the ultrasonic treatment time is 30 minutes; the inert gas is nitrogen; and the drying and calcining conditions are: calcining at a temperature of 500° C. to 550° C. for 4 to 6 hours.

[0020] Preferably, the mass fraction of sesbania gum in the sesbania gum solution in S4 is 1.5%; and the mass ratio of the activated carbon after impregnation and roasting to the sesbania gum in the sesbania gum solution is (2-7):1.

[0021] Preferably, the average specific surface area of ​​the activated carbon based on ferrous iron loaded petroleum coke gasification ash in S4 is 1640 m 2 / g~1800m 2 / g.

[0022] The present invention also provides an application of activated carbon based on ferrous iron loaded petroleum coke gasification ash prepared by the above preparation method, wherein the activated carbon based on ferrous iron loaded petroleum coke gasification ash is used for removing COD in metallurgical wastewater.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The present invention removes silicon, aluminum and heavy metals present in petroleum coke gasification ash by alkali washing and acid washing, and effectively activates the petroleum coke gasification ash to form more fine channels and expose more active sites, thereby obtaining purified and activated high-specific surface area activated carbon, realizing the activation and resource utilization of petroleum coke gasification ash.

[0025] 2. The present invention increases the hydrophilicity of petroleum coke by using a surfactant, and achieves effective impregnation of ferric salts under ultrasonic action by adding ferrous salts and an impregnation aid. After impregnation, the activated carbon can be used as an adsorbent for organic matter and an activator for Fenton's reagent.

[0026] 3. The activated carbon prepared by the present invention significantly improves the COD removal effect through the simultaneous adsorption-degradation mechanism, reducing the COD of wastewater to below 20 mg / L, shortening the wastewater treatment process and extending the service life of the activated carbon. The present invention will be further described in detail below with reference to the examples. DETAILED DESCRIPTION

[0027] Example 1

[0028] The preparation method of the activated carbon based on ferrous-loaded petroleum coke gasification ash in the embodiment is as follows:

[0029] S1, crushing, grinding and sieving the petroleum coke gasification ash to obtain sieved petroleum coke gasification ash with a particle size of <50 μm;

[0030] S2, under the condition that the temperature is 90℃, the sieved petroleum coke gasification ash obtained in S1 is sequentially subjected to sodium hydroxide alkali washing, water washing, sulfuric acid acid washing and water washing to obtain activated and purified activated carbon;

[0031] S3, 20 mL of a 0.5% sodium naphthalenesulfonate aqueous solution, 30 mL of a 0.5% sodium citrate aqueous solution and 70 mL of a 10 g / L ferrous sulfate aqueous solution are added to 100 g of the activated and purified activated carbon obtained in S2, and then stirred and mixed for impregnation for 80 min, followed by ultrasonic treatment for 30 min; and then dried and calcined at 500℃ under the protection of inert gas nitrogen for 6 h to obtain impregnated and calcined activated carbon;

[0032] The sodium naphthalenesulfonate is a surfactant, the sodium citrate is an auxiliary impregnant, and the ferrous sulfate is a ferrous salt;

[0033] S4, the impregnated and calcined activated carbon obtained in S3 is mixed with a 1.5% Euphorbia Anode Solution, and then dried at 120 for 6 h to obtain activated carbon based on ferrous-loaded petroleum coke gasification ash with an average specific surface area of 1800 m 2 / g. The mass ratio of the impregnated and calcined activated carbon to the Euphorbia Anode in the Euphorbia Anode Solution is 2:1.

[0034] Example 2

[0035] The preparation method of the activated carbon based on ferrous-loaded petroleum coke gasification ash in the embodiment is as follows:

[0036] S1, crushing, grinding and sieving the petroleum coke gasification ash to obtain sieved petroleum coke gasification ash with a particle size of <50 μm;

[0037] S2, under the condition that the temperature is 80℃, the sieved petroleum coke gasification ash obtained in S1 is sequentially subjected to sodium hydroxide alkali washing, water washing, sulfuric acid acid washing and water washing to obtain activated and purified activated carbon;

[0038] S3, to the activated carbon after the activation purification obtained among 100g S2, adding 30mL mass fraction and be 0.5% sodium naphthalenesulfonate aqueous solution, 50mL mass fraction and be 0.5% sodium citrate aqueous solution, 60mL concentration and be 10g / L ferrous sulfate aqueous solution and carry out stirring and mixing and impregnation 80min, then ultrasonic treatment 30min, under inert gas nitrogen protection, carry out drying and roasting 4h at 550 DEG C, to obtain the activated carbon after impregnation and roasting;

[0039] Among them, sodium naphthalenesulfonate is a surfactant, sodium citrate is a leaching aid, and ferrous sulfate is a ferrous salt;

[0040] S4: The activated carbon obtained in S3 after impregnation and calcination was mixed with a 1.5% sesbania gum solution, and dried at 105°C for 8 hours to obtain an average specific surface area of ​​1640 m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash; the mass ratio of the activated carbon after impregnation and roasting to the sesbania gum in the sesbania gum solution is 7:1.

[0041] Example 3

[0042] The preparation method of activated carbon based on ferrous iron loaded petroleum coke gasification ash of this embodiment is as follows:

[0043] S1. Crushing, grinding, and sieving petroleum coke gasification ash to obtain sieved petroleum coke gasification ash with a particle size of less than 50 μm;

[0044] S2. At a temperature of 80° C., the sieved petroleum coke gasification ash obtained in S1 is sequentially subjected to sodium hydroxide alkali washing, water washing, sulfuric acid acid washing, and water washing to obtain activated and purified activated carbon;

[0045] S3, to the activated carbon after the activation purification obtained among 100g S2, adding 10mL mass fraction and be 0.5% sodium naphthalenesulfonate aqueous solution, 20mL mass fraction and be 0.5% sodium citrate aqueous solution, 60mL concentration and be 10g / L ferrous sulfate aqueous solution and carry out stirring and mixing and impregnation 80min, then ultrasonic treatment 30min, under inert gas nitrogen protection, carry out drying and roasting 5h at 530 DEG C, obtain the activated carbon after impregnation and roasting;

[0046] Among them, sodium naphthalenesulfonate is a surfactant, sodium citrate is a leaching aid, and ferrous sulfate is a ferrous salt;

[0047] S4: The activated carbon obtained in S3 after impregnation and calcination was mixed with a 1.5% sesbania gum solution, and dried at 110°C for 7 hours to obtain an average specific surface area of ​​1640 m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash; the mass ratio of the activated carbon after impregnation and roasting to the sesbania gum in the sesbania gum solution is 5:1.

[0048] Comparative Example 1

[0049] The activated carbon based on ferrous sulfate loaded petroleum coke gasification ash prepared in this comparative example is the same as that in Example 1, except that the concentration of the ferrous sulfate aqueous solution in step S3 is 1 g / L and the amount added is 80 mL, and the average specific surface area of ​​the prepared activated carbon is 1800 m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash.

[0050] Comparative Example 2

[0051] The activated carbon based on ferrous iron loaded petroleum coke gasification ash prepared in this comparative example is the same as that in Example 1, except that no sodium naphthalenesulfonate aqueous solution is added in step S3, and the average specific surface area of ​​the prepared activated carbon is 1800 m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash.

[0052] Comparative Example 3

[0053] The activated carbon based on ferrous iron loaded petroleum coke gasification ash prepared in this comparative example is the same as that in Example 1, except that no sodium citrate aqueous solution is added in step S3. The average specific surface area of ​​the activated carbon prepared is 1800 m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash.

[0054] The activated carbons based on ferrous iron loaded petroleum coke gasification ash prepared in Examples 1-3 and Comparative Examples 1-3 were used for COD removal in metallurgical wastewater.

[0055] High-salt, high-COD wastewater generated during nickel recovery using a hydrometallurgical extraction process at a certain enterprise had a COD of 650 mg / L. The COD was attributed to residual extractant, primarily composed of organic sulfonic acids and esters. Water samples collected on the same day were treated with the activated carbons prepared from ferrous iron-loaded petroleum coke gasification ash, prepared in Examples 1-3 and Comparative Examples 1-3, using hydrogen peroxide as the oxidant, at a rate of 2 g of finished activated carbon per liter of wastewater. Chemical oxygen demand (COD) was measured using the potassium dichromate method according to GB / T 34500.2, "Determination of Chemical Oxygen Demand (COD)." The results are shown in Table 1.

[0056] Table 1 Test results

[0057] project COD after removal / mg / L Example 1 8 Example 2 12 Example 3 13 Comparative Example 1 58 Comparative Example 2 83 Comparative Example 3 73

[0058] As shown in Table 1, embodiment 1-3 within the scope of the present invention can effectively reduce COD to less than 20ppm, and comparative example 1 is different from embodiment 1 in that, in activated carbon, the concentration of the ferrous iron of effective load is low, and its activation Fenton reagent produces free radical ability limited, and the free radical deficiency produced in advanced oxidation process is poor to organic removal effect, so COD is higher.Comparative example 2 is different from embodiment 1 in that not adding surfactant, the effect of surfactant is to improve the hydrophilic property of activated carbon, improves the load effect of iron, and comparative example 2 does not add surfactant and causes the effective load amount of iron to reduce, and the effect of generation is similar to comparative example 1, and the effective activation of Fenton reagent can not be realized, thus causes COD removal effect to be slightly poor.In comparative example 3, not adding leaching agent, leaching agent main function is to prevent the oxidation of iron, and makes the existence form of iron to be ferrous iron, and because of the poor ability of ferric iron activation Fenton reagent, therefore in comparative example 3, the effective load amount of iron is low, and COD removal effect is poor.

[0059] The present invention removes silicon, aluminum and heavy metals present in petroleum coke gasification ash by alkali washing and acid washing, and effectively activates the petroleum coke gasification ash to form more fine pores and expose more active sites, thereby obtaining purified and activated high-specific surface area activated carbon, realizing the activation and resource utilization of petroleum coke gasification ash.

[0060] The present invention increases the hydrophilicity of petroleum coke through the use of surfactants, and by adding ferrous salts and soaking aids, achieves effective impregnation of ferrous iron under the action of ultrasound. The activated carbon thus prepared is in situ loaded with ferrous iron, and has the characteristics of well-developed pores and a high specific surface area, which can effectively adsorb organic sulfonic acids and ester organic matter in the solution. The loaded ferrous iron can also act as an activator for Fenton's reagent, activating hydrogen peroxide or persulfate to produce hydroxyl radicals or sulfate radicals, which directly act on the in situ adsorbed organic matter to achieve oxidative degradation, thereby extending the service life of the activated carbon. Traditional advanced oxidation-activated carbon tandem technology involves two processes: advanced oxidation degradation and activated carbon adsorption. The process is long and has the disadvantage of being easily saturated because the adsorbed organic matter cannot be effectively degraded.

[0061] The activated carbon prepared by the present invention significantly improves the COD removal effect through the simultaneous adsorption-degradation mechanism, reduces the COD of wastewater to below 20 mg / L, shortens the process flow of wastewater treatment, and increases the service life of the activated carbon.

[0062] The activated carbon prepared by the present invention based on ferrous loaded petroleum coke gasification ash for removing COD has the characteristics of simple process operation, short process flow and long service life of the activated carbon, which solves the problems in the prior art of long process flow, easy saturation of activated carbon and high operating cost of removing COD by activated carbon in series using advanced oxidation technology.

[0063] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash, characterized in that: The method is: S1. Crushing, grinding, and sieving petroleum coke gasification ash to obtain sieved petroleum coke gasification ash; S2. Under the condition of a temperature of 80° C. to 90° C., the sieved petroleum coke gasification ash obtained in S1 is sequentially subjected to alkali washing, water washing, acid washing, and water washing to obtain purified petroleum coke gasification ash; S3, add surfactant aqueous solution, soaking agent aqueous solution, ferrous salt aqueous solution to the purified petroleum coke gasification ash obtained in S2, stir and mix, soak, then ultrasonicate, dry and roast under nitrogen protection, to obtain activated carbon after soaking and roasting; the concentration of the ferrous salt aqueous solution is 10g / L; the surfactant in the surfactant aqueous solution is sodium naphthalenesulfonate, and the soaking agent in the soaking agent aqueous solution is sodium citrate; S4. The activated carbon obtained in S3 and the impregnated and calcined activated carbon is mixed with the sesbania gum solution, and dried to obtain activated carbon based on ferrous iron loaded petroleum coke gasification ash.

2. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The particle size of the sieved petroleum coke gasification ash in S1 is less than 50 μm.

3. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The mass fraction of the surfactant in the surfactant aqueous solution in S3 is 0.5%, and the mass fraction of the immersion aid in the immersion aid aqueous solution is 0.5%; the dosage ratio of the purified petroleum coke gasification ash, surfactant aqueous solution, immersion aid aqueous solution and ferrous salt aqueous solution is 100 g: (10~30) mL: (20~50) mL: (60~70) mL.

4. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 3, characterized in that: The ferrous salt of the ferrous salt aqueous solution is ferrous sulfate.

5. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The stirring, mixing and impregnation time in S3 is 80 minutes, and the ultrasonic treatment time is 30 minutes; the drying and calcining conditions are: calcining at a temperature of 500° C. to 550° C. for 4 hours to 6 hours.

6. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The drying conditions in S4 are: drying at a temperature of 105°C to 120°C for 6h to 8h.

7. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The mass fraction of sesbania gum in the sesbania gum solution described in S4 is 1.5%; the mass ratio of the activated carbon after impregnation and roasting to the sesbania gum in the sesbania gum solution is (2~7):

1.

8. The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash according to claim 1, characterized in that: The average specific surface area of ​​the activated carbon based on ferrous iron loaded petroleum coke gasification ash in S4 is 1640 m 2 / g~1800m 2 / g.

9. An application of activated carbon based on ferrous iron loaded petroleum coke gasification ash prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The activated carbon based on ferrous iron loaded petroleum coke gasification ash is used for removing COD in metallurgical wastewater.