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

Abstract

The invention 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; the preparation method comprises the following steps: performing alkali washing, water washing, acid washing and water washing on sieved petroleum coke gasification ash at 80-90 DEG C to obtain activated and purified activated carbon, adding a surfactant aqueous solution, a leaching aid aqueous solution and a ferrite aqueous solution, stirring, mixing and dipping, performing ultrasonic treatment, drying and roasting under inert gas to obtain dipped and roasted activated carbon, mixing the dipped and roasted activated carbon with a sesbania gum solution, and drying and roasting under inert gas to obtain the activated carbon. And drying to obtain the product. The invention also provides an application for removing COD in metallurgical wastewater. The process for removing COD based on the ferrous loaded petroleum coke gasification ash prepared by the invention has the characteristics of simple operation, short flow, long service life of the activated carbon and the like, and solves the problems of long process flow, easy saturation of the activated carbon and high operation cost of an advanced oxidation technology for removing COD through series connection of the activated carbon in the prior art.

Description

Technical Field

[0001] The 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 the waste residue produced in the process of petroleum coke gasification. It is the residue produced after the carbon in petroleum coke is fully utilized. It still contains rich carbon resources and is enriched with valuable heavy metal resources in crude oil, which limits its downstream application. At present, petroleum coke gasification ash is mainly used as fuel for disposal as solid waste. The combustion process produces a large amount of greenhouse gases, and at the same time, valuable resources are not fully utilized. Therefore, it has important environmental and social benefits to reasonably recover valuable resources, realize the effective utilization of carbon, and maximize the value of petroleum coke resources.

[0003] Extraction is currently an important means for the hydrometallurgical industry to achieve selective separation and purification of valuable metals. The extractant and diluent in the hydrometallurgical process will dissolve in the water phase to varying degrees, causing the COD in the residual wastewater to increase. The COD in the metallurgical extraction industry can be as high as 500-1000 mg / L. At the same time, the hydrometallurgical process will introduce a large amount of acid, alkali, salt, etc., resulting in high-salt and high-COD wastewater, which is difficult to biodegrade. The industry pain point faced by extraction hydrometallurgy is the problem of high COD in wastewater and difficulty in handling.

[0004] Activated carbon has a developed pore structure and has a strong physical adsorption effect on pollutants in aqueous solutions. However, activated carbon only acts as a location migration of COD storage substances and does not have a degradation effect. Therefore, multi-stage adsorption is often used to achieve COD removal. It is easy to adsorb saturated, and activated carbon needs to be regenerated after saturation. The operating cost of activated carbon is very high. Therefore, the adsorption effect of conventional commercial activated carbon on COD is not enough to meet the requirements of wastewater treatment.

[0005] Advanced oxidation technology is widely used in wastewater COD treatment due to its strong oxidation effect. However, further improving the COD degradation effect requires increasing the amount of oxidant. At the same time, the amount of iron sludge produced in the process is large and difficult to filter, and the operation and treatment costs are high. Therefore, advanced oxidation and activated carbon adsorption are often used in series to achieve the degradation and removal of organic matter, which has a long process flow 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 provide a method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash and its application in view of the shortcomings of the above-mentioned prior art. 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 life of activated carbon for removing COD, which solves the problems of long process flow, easy saturation and high operating cost of activated carbon in series removal of COD by advanced oxidation technology in the prior art.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing activated carbon based on ferrous iron 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. 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 activated and purified activated carbon;

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

[0012] S4, mixing the impregnated and calcined activated carbon obtained in S3 with the sesbania gum solution, and drying 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 10g / L; the dosage ratio of the activated carbon, surfactant aqueous solution, immersion aid aqueous solution and ferrous salt aqueous solution after activation and purification is 100g:(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 hours 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 calcination 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, thereby 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 realizes effective impregnation of ferric salt under ultrasonic action by adding ferrous salt 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 removal effect of COD through the adsorption-degradation mechanism, and the COD of wastewater is reduced to below 20 mg / L, which shortens the process of wastewater treatment and increases the service life of the activated carbon. The present invention is further described in detail below in conjunction with the embodiments. DETAILED DESCRIPTION

[0027] Example 1

[0028] The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash of this embodiment is as follows:

[0029] 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;

[0030] S2. At a temperature of 90° C., the sieved petroleum coke gasification ash obtained in S1 is sequentially washed with sodium hydroxide, washed with water, washed with sulfuric acid, and washed with water to obtain activated and purified activated carbon;

[0031] S3, to the activated carbon obtained in 100g S2 after the activation and purification, add 20mL of sodium naphthalenesulfonate aqueous solution with a mass fraction of 0.5%, 30mL of sodium citrate aqueous solution with a mass fraction of 0.5%, and 70mL of ferrous sulfate aqueous solution with a concentration of 10g / L, stir and mix, and impregnate for 80min, then ultrasonically treat for 30min, and dry and calcine at 500°C for 6h under the protection of inert gas nitrogen, and the conditions of drying and calcining are to obtain the activated carbon after impregnation and calcination;

[0032] Among them, sodium naphthalenesulfonate is a surfactant, sodium citrate is a leaching aid, and ferrous sulfate is a ferrous salt;

[0033] S4, the activated carbon obtained in S3 after impregnation and calcination was mixed with a 1.5% sesbania gum solution, and dried at 120°C for 6 hours to obtain an average specific surface area of ​​1800 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 2:1.

[0034] Example 2

[0035] The method for preparing activated carbon based on ferrous iron loaded petroleum coke gasification ash of this embodiment is as follows:

[0036] 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;

[0037] S2. At a temperature of 80° C., the sieved petroleum coke gasification ash obtained in S1 is sequentially washed with sodium hydroxide, washed with water, washed with sulfuric acid, and washed with water to obtain activated and purified activated carbon;

[0038] S3, to 100g of the activated carbon obtained in S2 after the activation and purification, add 30mL of a 0.5% sodium naphthalenesulfonate aqueous solution, 50mL of a 0.5% sodium citrate aqueous solution, and 60mL of a 10g / L ferrous sulfate aqueous solution, stir and mix, and impregnate for 80min, then ultrasonically treat for 30min, and dry and calcine at 550°C for 4h under the protection of inert gas nitrogen to obtain the activated carbon after impregnation and calcination;

[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 method for preparing 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 washed with sodium hydroxide, washed with water, washed with sulfuric acid, and washed with water to obtain activated and purified activated carbon;

[0045] S3, to 100g of the activated carbon obtained in S2 after the activation and purification, add 10mL of a 0.5% sodium naphthalenesulfonate aqueous solution, 20mL of a 0.5% sodium citrate aqueous solution, and 60mL of a 10g / L ferrous sulfate aqueous solution, stir and mix, and impregnate for 80min, then ultrasonically treat for 30min, and dry and calcine at 530°C for 5h under the protection of inert gas nitrogen to obtain the activated carbon after impregnation and calcination;

[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 calcination 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, 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 1800m 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, and the average specific surface area of ​​the prepared activated carbon is 1800m 2 / g of activated carbon based on ferrous iron loaded petroleum coke gasification ash.

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

[0055] The high-salt and high-COD wastewater generated in the process of recovering nickel by a hydrometallurgical extraction method of a certain enterprise was collected. The COD was 650 mg / L. The reason for the COD was the residual extractant, and the main components were organic sulfonic acids and esters. With the standard of adding 2g of activated carbon finished product per liter of sewage, hydrogen peroxide was used as the oxidant, and the activated carbon based on ferrous-loaded petroleum coke gasification ash prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was used to treat the water samples collected on the same day. The potassium dichromate method of GB / T 34500.2 "Determination of Chemical Oxygen Demand (COD)" was used for determination, and 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, embodiments 1-3 within the scope of the present invention can effectively reduce COD to less than 20ppm, and the difference between comparative example 1 and embodiment 1 is that the concentration of the ferrous iron of effective load in activated carbon is low, and its ability to activate Fenton's reagent to produce free radicals is limited, and the free radicals produced in the advanced oxidation process are insufficient, and the removal effect of organic matter is poor, so COD is high. The difference between comparative example 2 and embodiment 1 is that no surfactant is added, and the role of surfactant is to improve the hydrophilicity of activated carbon, improve the loading effect of iron, and comparative example 2 does not add surfactant to cause the effective load amount of iron to reduce, and the effect produced is similar to comparative example 1, and the effective activation of Fenton's reagent can not be achieved, so as to cause COD removal effect to be slightly poor. No leaching aid is added in comparative example 3, and the main function of leaching aid is to prevent the oxidation of iron, so that the existence form of iron is ferrous iron, because the ability of ferric iron to activate Fenton's reagent is poor, so the effective load amount of iron in comparative example 3 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, thereby realizing the activation and resource utilization of petroleum coke gasification ash.

[0060] The present invention increases the hydrophilicity of petroleum coke by using a surfactant, and realizes effective impregnation of ferrous iron under ultrasonic action by adding ferrous salt and a soaking aid. The activated carbon thus prepared is in-situ loaded with ferrous iron, and has the characteristics of well-developed pores and high specific surface area, and can effectively adsorb organic sulfonic acid and ester organic matter in the solution; and the loaded ferrous iron can be used as an activator of Fenton's reagent to activate hydrogen peroxide or persulfate to generate hydroxyl radicals or sulfate radicals, and directly act on the organic matter adsorbed in-situ to realize its oxidative degradation, thereby increasing the service life of the activated carbon. The traditional advanced oxidation-activated carbon tandem technology is a two-step process of advanced oxidation degradation and activated carbon adsorption, with a long process, and because the adsorbed organic matter cannot be effectively degraded, it has the disadvantage of being easily saturated.

[0061] The activated carbon prepared by the present invention significantly improves the removal effect of COD through the adsorption-degradation simultaneous action 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 iron 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 existing in the prior art of long process flow of activated carbon series for removing COD by advanced oxidation technology, easy saturation of activated carbon and high operating cost.

[0063] The above 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 change made to the above embodiment according to the technical essence of the invention still falls within the protection scope 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 activated and purified activated carbon; S3, adding a surfactant aqueous solution, an immersion aid aqueous solution, and a ferrous salt aqueous solution to the activated carbon obtained in S2 for stirring, mixing, and impregnation, then ultrasonically treating, and drying and calcining under the protection of an inert gas to obtain activated carbon after impregnation and calcination; S4, mixing the impregnated and calcined activated carbon obtained in S3 with the sesbania gum solution, and drying 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 concentration of the ferrous salt aqueous solution is 10g / L; the dosage ratio of the activated carbon, surfactant aqueous solution, immersion aid aqueous solution and ferrous salt aqueous solution after activation and purification is 100g:(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 surfactant is sodium naphthalenesulfonate, the leaching aid is sodium citrate, and 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 inert gas is nitrogen; 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 6 h to 8 h.

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 from metallurgical wastewater.