Modified activated carbon adsorption filter element

Abstract

The invention belongs to the technical field of activated carbon and sewage treatment, and particularly relates to a modified activated carbon adsorption filter element. Peels of musaceae musa species are used as raw materials, cobalt nitrate is used as an activating agent for activation, finally, a NaOH solution is used for carrying out alkalization treatment on the charcoal, the pore structure and surface functional groups of the activated carbon are further increased, and therefore the adsorption capacity of the activated carbon is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon and sewage treatment, and particularly relates to a modified activated carbon adsorption filter element. Background Art

[0002] Power plant boilers, also known as "power plant boilers", refer to medium and large boilers in power plants that provide a specified amount and quality of steam to steam turbines. One of the main thermal equipment in thermal power plants. The water quality must meet the relevant requirements of "GB / T12145-2016 Water and Steam Quality for Thermal Power Generators and Steam Power Equipment"; such as iron and copper ion concentrations, TOC (total organic carbon), conductivity, etc. Therefore, under normal circumstances, tap water, river water, and sewage treated water that meets the discharge standards cannot meet the requirements and must be treated before use.

[0003] At present, general power plants use tap water or fresh water as raw water for boiler water preparation, and most of them use fiber filters, ion exchange systems and activated carbon filters alone or in combination to prepare relevant water.

[0004] The activated carbon filter uses adsorption to remove organic matter from the water, and can also remove residual chlorine, grease, colloidal silica and suspended matter in the water, thereby delaying the contamination of the anionic resin and extending the life of the resin.

[0005] However, unmodified activated carbon has few surface active groups and low porosity, resulting in poor adsorption performance. Therefore, modification of activated carbon becomes a necessary step in the further utilization of activated carbon; at the same time, the source of activated carbon also has a significant impact on its performance; so if you want to improve the adsorption performance of activated carbon, there are broad prospects from both the source of materials and modification. Summary of the invention

[0006] The present invention provides a modified activated carbon adsorption filter element, which obtains better adsorption capacity through specific carbon material selection and activation method.

[0007] A method for preparing a modified activated carbon adsorption filter element, characterized in that it comprises the steps of:

[0008] S1 Pretreatment: Take the peel of the species of the genus Musa in the Musaceae family, wash it and then dry it to obtain a pretreatment sample;

[0009] S2 activation: Activate the pre-treated sample with cobalt nitrate, wash and dry to obtain biochar A;

[0010] S3 modification: Biochar A is alkalized using NaOH to obtain activated carbon with high adsorption capacity.

[0011] Preferably, the pre-treatment in step S1 is drying at ≥100° C. for at least 12 h.

[0012] Preferably, the activation in step S2 is performed by soaking the biochar in a cobalt nitrate solution and then roasting it.

[0013] Preferably, in the activation step S2: the cobalt nitrate is a cobalt nitrate solution with a concentration of 7.0-8.0 wt%.

[0014] Preferably, in the activation step S2, the impregnation ratio of the cobalt nitrate solution is 1.2-1.7:5 g / ml, and the impregnation time is ≥90 min.

[0015] Preferably, in the activation step S2, the calcination temperature is ≥ 600°C and the calcination time is ≥ 120 min.

[0016] Preferably, in the modification step S3, the NaOH is a NaOH solution with a concentration of 5-6 mol / l.

[0017] Preferably, in the modification step S3, the solid-liquid ratio is 45-55 ml:1 g.

[0018] Preferably, in the modification step S3, the NaOH solution is mixed with the biochar A, and soaked at 55-65°C for ≥4h; and then dried at ≥100°C for at least 12h.

[0019] The present invention uses the peel of the species of the genus Musa of the Musaceae family as a raw material, which has unique chemical composition and structural characteristics and is conducive to forming activated carbon with specific adsorption performance.

[0020] The present invention uses cobalt nitrate as an activator, which helps to introduce specific metal ions, thereby improving the adsorption performance of activated carbon. The control of the concentration, impregnation ratio and impregnation time of the cobalt nitrate solution is crucial to the activation effect. The conditions of roasting temperature ≥ 600°C and time ≥ 120 minutes help the cobalt nitrate and biochar to fully react to form activated carbon with high adsorption capacity.

[0021] The present invention uses NaOH solution to alkalize biochar to further increase the pore structure and surface functional groups of activated carbon, thereby improving its adsorption capacity. The concentration of NaOH solution, solid-liquid ratio, and control of soaking temperature and time are crucial to the modification effect. The drying step after alkalization treatment helps to remove residual NaOH and moisture, ensuring the purity and stability of activated carbon.

[0022] Compared with using KOH solution for alkalization, the present invention uses NaOH for alkalization, which can more effectively improve the adsorption capacity of activated carbon. DETAILED DESCRIPTION

[0023] In order to better understand the present invention, the present invention is further described below in conjunction with specific serial numbers, wherein the terms used in the serial numbers are for describing specific embodiments and do not constitute limitations on the scope of protection of the present invention.

[0024] Specific implementation methods, unless otherwise specified, are conventional experimental methods, and the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0025] The sources of some raw materials used in the present invention are as follows: Table 1:

[0026] Table 1

[0027] name Product Name / Model / Latin Name Source (Manufacturer) banana Musa acuminata 'Cavendish' PuPu Supermarket Plantain Musa×paradisiaca L. PuPu Supermarket banana Musa basjoo PuPu Supermarket Apple Powder Banana Musa acuminata, Musa acuminata PuPu Supermarket Chlorella Chlorella pyrenoid Guangzhou Tianjia Biotechnology Co., Ltd. Cobalt nitrate / Jinan Shanhai Chemical Technology Co., Ltd. Potassium hydroxide / Jinan Jinhao Chemical Co., Ltd. Sodium hydroxide / Jinan Jinhao Chemical Co., Ltd. potassium permanganate / Jinan Jinhao Chemical Co., Ltd. Sodium Potassium Persulfate / Jinan Jinhao Chemical Co., Ltd. Nitrogen / Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0028] Preparation of activated carbon

[0029] The preparation of activated carbon comprises the following steps:

[0030] 1. Take all the raw materials and cut them into pieces no larger than 3cm 3 small pieces; rinse with distilled water and air-dry for 2 days, place in an oven at 105℃ to dry for 10 hours; then place in a blender and grind through a 30-mesh sieve.

[0031] 2. Soak the sieved powder in a 7.0wt% cobalt nitrate solution at a ratio of 1.7:5g / ml for 90 minutes.

[0032] 3. After impregnation, place the solution and powder together in an activation furnace under nitrogen protection; heat to 600°C at a rate of 5°C / min, roast and keep warm for 120 minutes; after natural cooling, take out and crush through a 100-mesh sieve.

[0033] 4. Wash repeatedly until neutral, then dry and cool to obtain activated carbon.

[0034] Performance test of activated carbon

[0035] Test method:

[0036] The adsorption materials prepared in each embodiment and each comparative example were added into the simulated sewage at an addition amount of 30 g / L. After stirring and adsorbing at 60 rpm for 90 min, the corresponding pollutant content in the simulated sewage was detected and the removal rate was calculated.

[0037] The simulated sewage contains:

[0038] Nickel chloride content is 10mg / L

[0039] Zinc chloride content is 50mg / L

[0040] Copper sulfate content is 60mg / L

[0041] The content of iron nitrate is 60ml / L

[0042] At the same time, hydrochloric acid was used to adjust the pH to 5.

[0043] The results are shown in Table 2.

[0044] Table 2 Adsorption results

[0045]

[0046] The results in Table 2 show that Chlorella is not suitable for this activation method, while the adsorption effects of the remaining ivory banana, plantain, banana and apple powder banana are better than Chlorella. The present invention speculates that banana peel contains rich cellulose and lignin, and these organic substances can form a porous structure during the carbonization and activation process. These pores help to increase the specific surface area of ​​activated carbon, thereby enhancing its adsorption capacity; at the same time, the introduced cobalt ions may help to improve the adsorption performance of activated carbon, especially in specific types of ions such as Fe 3+ .

[0047] Cobalt nitrate activation test

[0048] The activated carbon prepared from ivory banana as raw material was used as the standard sample, and the following parameter changes were made.

[0049] Cobalt nitrate activated sample No. 1: The difference from the standard sample is that the concentration of cobalt nitrate in step 2 is 6.0 wt%.

[0050] Cobalt nitrate activated sample No. 2: The difference from the standard sample is that the concentration of cobalt nitrate in step 2 is 8.0 wt % and the impregnation ratio is 1.2:5 g / ml.

[0051] Cobalt nitrate activated sample No. 3: The difference from the standard sample is that the concentration of cobalt nitrate in step 2 is 8.5 wt % and the impregnation ratio is 1.2:5 g / ml.

[0052] Cobalt nitrate activated sample No. 4: The difference from the standard sample is that the concentration of cobalt nitrate in step 2 is 7.0 wt % and the impregnation ratio is 2.0:5 g / ml.

[0053] The adsorption test was carried out using the same test method as above, and the results are shown in Table 3.

[0054] Table 3 Adsorption results

[0055]

[0056]

[0057] It can be seen from the results of sample No. 3 in Table 3 that when cobalt nitrate is over-activated, the adsorption capacity decreases instead; the present invention speculates that the pore structure of the activated carbon may be over-eroded, especially the micropores may be over-enlarged into mesopores or macropores, thereby reducing the specific surface area and pore volume of the activated carbon.

[0058] From the results of samples No. 2 and No. 4, it can be seen that a lower activation degree will cause insufficient corrosion, resulting in a decrease in adsorption capacity.

[0059] Activated carbon modification test

[0060] The activated carbon prepared from ivory banana as raw material was used as the standard sample for modification test.

[0061] The preparation of modified sample No. 1 includes the following steps:

[0062] 1. Take the standard sample, add 5.0mol / L NaOH solution to alkalize it, and the solid-liquid ratio is 55ml:1g; stir at 60℃ for 4h to mix it evenly, and wash it with distilled water several times until it is neutral;

[0063] 2. Then place it in an oven at 105°C for drying, and pass it through a 150-mesh sieve to obtain modified activated carbon.

[0064] Preparation of modified sample No. 2: The difference from modified sample No. 1 is that the concentration of NaOH solution is 6.0 mol / L and the solid-liquid ratio is 45 ml:1 g.

[0065] Preparation of modified sample No. 3: The difference from modified sample No. 1 is that the concentration of NaOH solution is 7.0 mol / L and the solid-liquid ratio is 45 ml:1 g.

[0066] Preparation of modified sample No. 4: The difference from modified sample No. 1 is that KOH solution with the same concentration is used instead of NaOH solution.

[0067] Preparation of modified sample No. 5: The difference from modified sample No. 1 is that KMNO4 solution with the same concentration is used instead of NaOH solution.

[0068] Preparation of modified sample No. 6: The difference from modified sample No. 1 is that (NH4)2S2O8 solution with the same concentration is used instead of NaOH solution.

[0069] The adsorption test was carried out using the same test method as above, and the results are shown in Table 4.

[0070] Table 4 Adsorption results

[0071]

[0072]

[0073] The results in Table 4 show that the adsorption capacity will have obvious specific changes depending on the modifier; at the same time, over-activation or incorrect test parameters may lead to over-development of the pore structure of the activated carbon; in addition, due to the excessive increase of functional groups on the surface of the activated carbon, the adsorption capacity may eventually show obvious differentiation rather than a definite improvement in adsorption capacity.

[0074] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A method for preparing a modified activated carbon adsorption filter element, characterized in that: Includes steps: S1 Pretreatment: Take the peel of the species of the genus Musa in the Musaceae family, wash it and then dry it to obtain a pretreatment sample; S2 activation: Activate the pre-treated sample with cobalt nitrate, wash and dry to obtain biochar A; S3 modification: biochar A was alkalized using NaOH; Obtain activated carbon with high adsorption capacity.

2. The preparation method according to claim 1, characterized in that: The pre-treatment in step S1 is drying at ≥100°C for at least 12 hours.

3. The preparation method according to claim 1, characterized in that: The activation step S2 is to soak the biochar in a cobalt nitrate solution and then roast it.

4. The preparation method according to claim 3, characterized in that: In the activation step S2: the cobalt nitrate is a cobalt nitrate solution with a concentration of 7.0-8.0 wt%.

5. The preparation method according to claim 3, characterized in that: In the activation step S2, the impregnation ratio of the cobalt nitrate solution is 1.2-1.7:5 g / ml, and the impregnation time is ≥90 min.

6. The preparation method according to claim 3, characterized in that: In the activation step S2, the calcination temperature is ≥ 600°C and the calcination time is ≥ 120 min.

7. The preparation method according to claim 1, characterized in that: In the modification step S3, the NaOH is a NaOH solution with a concentration of 5-6 mol / l.

8. The preparation method according to claim 7, characterized in that: In the modification of step S3, the solid-liquid ratio is 45-55 ml:1 g.

9. The preparation method according to claim 7, characterized in that: In the modification of step S3, the NaOH solution is mixed with the biochar A, and soaked at 55-65° C. for ≥4 hours; and then dried at ≥100° C. for at least 12 hours.

10. A modified activated carbon adsorption filter element, characterized in that Prepared by the preparation method described in any one of claims 1 to 9.

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