CN117142470A - Sludge-based activated carbon, preparation method thereof and application thereof in sewage treatment - Google Patents
Sludge-based activated carbon, preparation method thereof and application thereof in sewage treatment Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 237
- 239000010802 sludge Substances 0.000 title claims abstract description 179
- 239000010865 sewage Substances 0.000 title claims abstract description 29
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000000203 mixture Substances 0.000 claims abstract description 67
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 41
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 33
- 238000009656 pre-carbonization Methods 0.000 claims abstract description 31
- 235000017060 Arachis glabrata Nutrition 0.000 claims abstract description 26
- 241001553178 Arachis glabrata Species 0.000 claims abstract description 26
- 235000010777 Arachis hypogaea Nutrition 0.000 claims abstract description 26
- 235000018262 Arachis monticola Nutrition 0.000 claims abstract description 26
- 235000020232 peanut Nutrition 0.000 claims abstract description 26
- 238000002791 soaking Methods 0.000 claims abstract description 25
- 239000000126 substance Substances 0.000 claims abstract description 23
- STZCRXQWRGQSJD-GEEYTBSJSA-M methyl orange Chemical compound [Na+].C1=CC(N(C)C)=CC=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-GEEYTBSJSA-M 0.000 claims abstract description 22
- 229940012189 methyl orange Drugs 0.000 claims abstract description 22
- 238000005406 washing Methods 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 25
- 238000003763 carbonization Methods 0.000 claims description 23
- 238000001035 drying Methods 0.000 claims description 18
- 230000000630 rising effect Effects 0.000 claims description 14
- 238000000227 grinding Methods 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 12
- 238000005470 impregnation Methods 0.000 claims description 6
- 238000010000 carbonizing Methods 0.000 claims description 5
- 238000001179 sorption measurement Methods 0.000 abstract description 89
- 238000004064 recycling Methods 0.000 abstract description 4
- 238000003912 environmental pollution Methods 0.000 abstract description 3
- 238000004065 wastewater treatment Methods 0.000 abstract description 3
- 239000002910 solid waste Substances 0.000 abstract description 2
- 239000002699 waste material Substances 0.000 abstract description 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 65
- 229920006395 saturated elastomer Polymers 0.000 description 34
- 239000000243 solution Substances 0.000 description 32
- 238000007873 sieving Methods 0.000 description 30
- 230000004048 modification Effects 0.000 description 21
- 238000012986 modification Methods 0.000 description 21
- 239000012299 nitrogen atmosphere Substances 0.000 description 20
- 239000011148 porous material Substances 0.000 description 17
- 238000002835 absorbance Methods 0.000 description 16
- 239000011651 chromium Substances 0.000 description 14
- 229910001385 heavy metal Inorganic materials 0.000 description 14
- 239000002351 wastewater Substances 0.000 description 13
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 12
- 230000008859 change Effects 0.000 description 10
- 238000001816 cooling Methods 0.000 description 10
- 239000008367 deionised water Substances 0.000 description 10
- 229910021641 deionized water Inorganic materials 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 238000010298 pulverizing process Methods 0.000 description 10
- 229910052799 carbon Inorganic materials 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 229910001430 chromium ion Inorganic materials 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000012086 standard solution Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 229910052804 chromium Inorganic materials 0.000 description 5
- 125000000524 functional group Chemical group 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 238000001878 scanning electron micrograph Methods 0.000 description 4
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- STZCRXQWRGQSJD-UHFFFAOYSA-M sodium;4-[[4-(dimethylamino)phenyl]diazenyl]benzenesulfonate Chemical compound [Na+].C1=CC(N(C)C)=CC=C1N=NC1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-UHFFFAOYSA-M 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 238000004332 deodorization Methods 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000003760 magnetic stirring Methods 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 2
- 229910001414 potassium ion Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- 229910014033 C-OH Inorganic materials 0.000 description 1
- 229910014570 C—OH Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 244000052616 bacterial pathogen Species 0.000 description 1
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- 239000011449 brick Substances 0.000 description 1
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- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
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- 238000010494 dissociation reaction Methods 0.000 description 1
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- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 239000010841 municipal wastewater Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
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- 238000002336 sorption--desorption measurement Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000004441 surface measurement Methods 0.000 description 1
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- Carbon And Carbon Compounds (AREA)
Abstract
The application provides a sludge-based activated carbon, a preparation method and application thereof in sewage treatment, and belongs to the technical field of recycling treatment of industrial solid wastes. The application dries and then pulverizes the mud, and mix with peanut shell to get the mixture, pre-carbonize the said mixture, soak the mixture of pre-carbonization in KOH solution, wash the mixture after soaking, carbonize, get the carbonized chemical sludge, soak the said carbonized chemical sludge with nitric acid, and wash with water, filter, oven dry, grind, get the said mud-based activated carbon. The prepared sludge-based activated carbon has excellent adsorption performance on Cr (VI), methyl orange and COD in sewage. The application not only solves the environmental pollution caused by sludge, but also realizes waste utilization when the sludge is used in wastewater treatment.
Description
Technical Field
The application belongs to the technical field of recycling treatment of industrial solid wastes, and particularly relates to sludge-based activated carbon, a preparation method thereof and application thereof in sewage treatment.
Background
Sludge is mainly a byproduct generated in the process of industrial product processing or water treatment. According to the sources, the sludge mainly comprises municipal sludge, paper mill sludge, metallurgical sludge, textile sludge, fabric dyeing mill sludge and oily sludge generated by oil fields and oil refineries, and the sludge often contains a large amount of harmful substances such as organic matters, heavy metal salts, pathogenic bacteria and the like which are difficult to degrade, and is easy to cause serious harm to the environment, so that the sludge becomes a serious pollution source of soil, water sources and air. Therefore, rational treatment and disposal strategies are required to reduce environmental pollution.
The common sludge treatment modes and technologies of the sludge at present comprise incineration, sanitary landfill, energy desiccation, mechanical dehydration, anaerobic digestion, solidification brick making and the like. However, for chemical sludge with high content of harmful substances such as organic matters, microorganisms, heavy metals and the like, the treatment effect is not thorough, secondary pollution is easy to generate, investment is high, recycling is difficult, and the added value of products is low. The oil-containing sludge produced by petrochemical enterprises is more difficult to treat due to high yield, high asphaltene and colloid content in the sludge, and the like, and the mature harmless and recycling comprehensive utilization mode is less. Thus, there is still a need for further research and exploration for reasonable disposal of sludge.
In recent years, with the importance of society on ecological environment, water environment treatment technology has become one of the focus problems of attention of scientific researchers. The activated carbon has excellent adsorption performance, so that suspended particles, heavy metals and other substances in the water body can be removed, and meanwhile, deodorization and deodorization are realized, so that the activated carbon becomes an important adsorption purification material in the field of sewage purification. However, the existing activated carbon still cannot meet the requirements of the modern technology due to the characteristics of the existing activated carbon.
Disclosure of Invention
In order to solve the technical problems, the application provides a sludge-based activated carbon, a preparation method thereof and application thereof in sewage treatment.
In order to achieve the above purpose, the present application provides the following technical solutions:
one of the technical schemes of the application is as follows: the preparation method of the sludge-based activated carbon comprises the following steps: drying and crushing sludge, uniformly mixing the sludge with peanut shells to obtain a mixture, pre-carbonizing the mixture, soaking the pre-carbonized mixture in KOH solution, washing the soaked mixture, carbonizing to obtain carbonized chemical sludge, soaking the carbonized chemical sludge with nitric acid, washing with water, filtering, drying and grinding to obtain the sludge-based activated carbon.
Further, more specific steps are as follows: airing the sludge for 48 hours on a sunny day, then putting the sludge into an oven for drying at 120 ℃ for 2 hours, putting the sludge into a pulverizer for pulverizing, and sieving the sludge with a 40-mesh sieve; grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing sludge and the peanut shells to obtain a mixture, placing the mixture into a muffle furnace for pre-carbonization treatment, simultaneously protecting the mixture by nitrogen atmosphere, placing the pre-carbonized mixture into KOH solution for impregnation, washing the impregnated mixture to be alkalescent (pH=7-9) by deionized water, placing the mixture into a crucible for carbonization treatment under the nitrogen atmosphere, naturally cooling to obtain carbonized chemical sludge, impregnating the carbonized chemical sludge with nitric acid, washing the carbonized chemical sludge with water to be neutral, filtering, drying at 120 ℃, grinding and sieving with an 80-mesh sieve to obtain the sludge-based activated carbon.
Further, the mass ratio of the sludge to the peanut shells is 3:1.
Further, the temperature of the pre-carbonization treatment is 200 ℃, the temperature is kept for 2 hours, and the heating rate is 5 ℃/min.
Further, under the condition of higher potassium hydroxide concentration, collapse of active carbon pores can be caused, and higher potassium ions can be dissociated in the adsorption process, so that secondary pollution to water is caused, therefore, the concentration of the KOH solution is 1-3mol/L, and the time of soaking in the KOH solution is 24 hours. More preferably, the concentration of the KOH solution is 1mol/L. The application has no limit to the dosage of KOH solution, and only needs to uniformly mix the sludge and peanut shells to obtain the mixture.
Further, the carbonization treatment temperature is 600-700 ℃, the constant temperature is 2 hours, and the heating rate is 5 ℃/min. More preferably, the carbonization treatment temperature is 650 ℃. The lower temperature has no means to well form a good pore structure, while the higher temperature may collapse the pore channels, reduce the specific surface area and further reduce the adsorption performance of the activated carbon.
Further, the concentration of the nitric acid is 1mol/L, and the time for adding the nitric acid for soaking is 12 hours. The application has no limit to the dosage of nitric acid, and only needs to be done without carbonizing chemical sludge.
The second technical scheme of the application is as follows: the sludge-based activated carbon prepared by the preparation method.
The third technical scheme of the application: the application of the sludge-based activated carbon in sewage treatment.
Further, the sludge-based activated carbon is used for adsorbing Cr (VI), methyl orange and COD in sewage.
Further, when sludge-based activated carbon is used for adsorbing Cr (VI) in sewage, the optimal pH of the sewage is 4, the optimal feed ratio is 0.15g/mL of sewage, and the optimal Cr (VI) initial concentration in the sewage is 130mg/L.
Further, when the sludge-based activated carbon is used for adsorbing methyl orange in sewage, the optimal feeding ratio is 1.2g/L of sewage, the optimal initial concentration of methyl orange in sewage is 25mg/L, and the adsorption treatment time is controlled to be 20min.
Further, when the sludge-based activated carbon is used for adsorbing COD in sewage, the adsorption treatment time is controlled to be 50min, the optimal feeding ratio is 0.08g/mL of sewage,
compared with the prior art, the application has the following advantages and technical effects:
(1) The application takes the sludge as the raw material of the activated carbon, and has the characteristics of high carbon content and high asphaltene content, and the sludge has the characteristics of high carbon content and high asphaltene content, so that the sludge provides objective conditions for preparing the activated carbon, mineral substances in the sludge are not easy to remove in pyrolysis, and a carbon skeleton can be formed in the process. The application prepares the sludge-based activated carbon with specific surface area reaching 410.38m through alkali impregnation, carbonization treatment and acid modification 2 And/g, the surface oxygen-containing functional groups are increased, which is more beneficial to improving the adsorption performance of the activated carbon on Cr (VI), methyl orange and COD in sewage.
(2) The application not only solves the environmental pollution caused by sludge, but also is used in wastewater treatment to realize waste utilization, and has popularization and application values.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 shows the measurement results of the adsorption and desorption amount of the nitric acid-modified (carbonized chemical sludge) and nitric acid-modified (sludge-based activated carbon) products in example 1;
FIG. 2 is a graph showing pore distribution of the sludge-based activated carbon prepared in example 1 after nitric acid modification;
FIG. 3 is an SEM image of carbonized chemical sludge before modification with nitric acid in example 1;
FIG. 4 is an SEM image of the sludge-based activated carbon after nitric acid modification of example 1;
FIG. 5 shows FT-IR analysis results of sample 650-1M prepared in example 4 and carbonized chemical sludge prepared in example 4;
FIG. 6 is a graph of the absorbance standard of potassium dichromate solution;
FIG. 7 shows the saturated adsorption capacity results of sludge-based activated carbon at different pH values;
FIG. 8 shows the saturated adsorption capacity result (Cr (VI)) of sludge-based activated carbon at different feed ratios;
FIG. 9 is a graph showing the saturated adsorption capacity of sludge-based activated carbon in chromium-containing wastewater with different initial concentrations;
FIG. 10 is a graph of the absorbance standard of methyl orange solution;
FIG. 11 shows the saturated adsorption capacity results (methyl orange) of sludge-based activated carbon at different feed ratios;
FIG. 12 is a graph showing the saturated adsorption capacity of sludge-based activated carbon in methyl orange wastewater of different initial concentrations;
FIG. 13 is a graph showing the results of the adsorption amount of 650-1M methyl orange by the sample over time;
FIG. 14 shows the effect of different sludge-based activated carbon dosing on COD removal rate in wastewater;
FIG. 15 shows the effect of sludge-based activated carbon on the removal rate of COD in wastewater at different adsorption times.
Detailed Description
Various exemplary embodiments of the application will now be described in detail, which should not be considered as limiting the application, but rather as more detailed descriptions of certain aspects, features and embodiments of the application.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the application described herein without departing from the scope or spirit of the application. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present application. The specification and examples of the present application are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
The sludge used in the embodiment of the application is collected from Qingjiang petrochemical Limited liability company in Huaian city according to CJ/T221-2005 method for testing sludge from municipal wastewater treatment plant sludge inspection method, the result of the measurement of moisture and ash content of sludge was 30.38% and the ash content was 45.52%, using a TGA/SDTA 85le thermogravimetric analyzer, under an inert gas (N 2 ) The volatile content (organic content) obtained in the sludge was 54.48% as measured under protection.
The content of heavy metal elements in the sludge is measured by using an ICP spectrometer, and the content of Cr in the sludge is measured to be 3.41mg/kg, the content of Cu is measured to be 24.43mg/kg, the content of Fe is measured to be 2592.78mg/kg, the content of Mn is measured to be 113.83mg/kg, and the content of Ni is measured to be 7.89mg/kg. It can be seen that the raw sludge sample contains more heavy metals, especially iron and manganese, which may be introduced into the sludge due to the loss of the catalyst during the process, and impurities from the raw materials of the process, if not treated, may be dissociated into liquid during the adsorption of activated carbon, thereby generating secondary pollution to the sewage, and thus, it is necessary to pretreat the sludge to separate or solidify heavy metal ions in advance.
The raw materials used in the performance testing process of the examples of the present application are purchased from sources shown in Table 1.
Table 1 experimental materials and reagents
The experimental instrument information used in the experimental procedure of the present application is shown in table 2.
Table 2 laboratory instrument information table
The technical scheme of the application is further described by the following examples.
Example 1
Airing sludge for 48 hours on a sunny day, then putting the sludge into an oven for drying for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, wherein the pre-carbonization treatment temperature is 200 ℃, the constant temperature is 2 hours, the heating rate is 5 ℃/min, and the nitrogen atmosphere is used for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 1mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the carbonization treatment temperature at 600 ℃, the heating rate at 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording 600-1M.
Example 2
Airing sludge for 48 hours on a sunny day, then putting the sludge into an oven for drying for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, wherein the pre-carbonization treatment temperature is 200 ℃, the constant temperature is 2 hours, the heating rate is 5 ℃/min, and the nitrogen atmosphere is used for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 2mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the carbonization treatment temperature at 600 ℃, the heating rate at 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 600-2M.
Example 3
Airing sludge for 48 hours on a sunny day, then putting the sludge into an oven for drying for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, wherein the pre-carbonization treatment temperature is 200 ℃, the constant temperature is 2 hours, the heating rate is 5 ℃/min, and the nitrogen atmosphere is used for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 3mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the carbonization treatment temperature at 600 ℃, the heating rate at 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve, thus obtaining sludge-based activated carbon, and recording as 600-3M.
Example 4
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 1mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 650 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 650-1M.
Example 5
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 2mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be alkalescent (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 650 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 650-2M.
Example 6
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 3mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 650 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 650-3M.
Example 7
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 1mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 700 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 700-1M.
Example 8
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 2mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 700 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 700-2M.
Example 9
Sunning sludge for 48 hours on a sunny day, then putting the sludge into an oven for baking for 2 hours at 120 ℃, putting the sludge into a pulverizer for pulverization, sieving with a 40-mesh sieve, grinding peanut shells, sieving with an 80-mesh sieve, uniformly mixing the sludge and the peanut shells according to the mass ratio of 3:1 to obtain a mixture, putting the mixture into a muffle furnace for pre-carbonization treatment, keeping the temperature of the pre-carbonization treatment at 200 ℃, keeping the temperature for 2 hours at a temperature rising rate of 5 ℃/min, simultaneously keeping the nitrogen atmosphere for protection, putting the pre-carbonization treated mixture into a KOH solution with the concentration of 3mol/L for soaking for 24 hours, washing the soaked mixture with deionized water to be slightly alkaline (pH=7-9), putting the soaked mixture into a crucible for carbonization treatment under the nitrogen atmosphere, keeping the temperature of 700 ℃, keeping the temperature rising rate of 5 ℃/min, naturally cooling to obtain carbonized sludge, soaking the carbonized sludge with nitric acid with the concentration of 1mol/L for 12 hours, washing with water to neutrality, filtering, drying at 120 ℃, and sieving with an 80-mesh sieve to obtain sludge-based activated carbon, and recording as 700-3M.
Comparative example 1
The difference from example 4 is only that the nitric acid with a concentration of 1mol/L was replaced by phosphoric acid with a concentration of 1mol/L by an equal volume.
Comparative example 2
The same as in example 4 was repeated except that the nitric acid having a concentration of 1mol/L was replaced with a potassium hydroxide solution having a concentration of 1mol/L by the equivalent volume.
Performance testing
1. Specific surface measurement method (BET method)
At 77.3K, the pore structure and the change of the specific surface area are characterized by drawing a nitrogen adsorption-desorption curve.
The measurement results of the adsorption and desorption amounts of the nitric acid-modified (carbonized chemical sludge) and nitric acid-modified (sludge-based activated carbon) products in example 1 are shown in FIG. 1.
As can be seen from FIG. 1, the nitrogen adsorption capacity of the activated carbon material after nitric acid modification is obviously larger than that before modification, thereby calculating the specific surface area 372.63m before modification 2 Per gram, total pore volume 0.48cm 3 /g, average pore size 3.45; specific surface area after modification 410.38m 2 Per gram, total pore volume 0.54cm 3 /g, average pore size 3.35. When the change relation between the adsorption quantity and the relative pressure is smaller than 0.6, the adsorption quantity is increased along with the increase of the relative pressure; when the adsorption amount is between 0.6 and 1.0, the adsorption amount is gradually changed.
The pore distribution diagram of the sludge-based activated carbon prepared in example 1 after nitric acid modification is shown in fig. 2, and as can be seen from fig. 2, the pore distribution of the obtained sludge-based activated carbon is mainly concentratedIn the range and mainly comprises macropores.
2. Scanning electron microscope characterization (SEM)
SEM detection was performed on the products before modification of nitric acid (carbonized chemical sludge) and after modification of nitric acid (sludge-based activated carbon) in example 1 by SEM at a Huaiyin institute of education and testing, and the results are shown in fig. 3 and fig. 4, wherein fig. 3 is an SEM image of carbonized chemical sludge before modification of nitric acid in example 1, and fig. 4 is an SEM image of sludge-based activated carbon after modification of nitric acid in example 1.
Comparing fig. 3 and fig. 4, it can be found that under the same magnification, the surface impurities of the carbonized chemical sludge before modification by nitric acid are more, the pore channels are blocked, the surface of the sludge-based activated carbon subjected to physical activation and chemical modification is obviously increased in pores, and the surface folding degree is higher, so that the specific surface area of the activated carbon is increased, and the adsorption performance of the activated carbon is improved.
3. Fourier transform infrared spectroscopy (FT-IR) analysis
The sample 650-1M (after nitric acid modification) prepared in example 4 and carbonized chemical sludge (before nitric acid modification) prepared in example 4 are respectively ground, mixed with potassium bromide according to a certain proportion, and pressed into tablets, and the obtained mixture is subjected to scanning spectrum by an infrared spectrometer, wherein the scanning range is 400cm -1 ～4000cm -1 . The detection results are shown in FIG. 5.
As can be seen from FIG. 5, the sample 650-1M of the activated carbon modified by nitric acid in example 4 is 1000-1100cm -1 The chromatographic peak in the wavelength range is significantly increased, probably because the C-OH groups on the surface of the sample are increased after the sample is modified by nitric acid, so that the wavelength chromatographic peak generated by the stretching vibration of the C-O groups is superposed. The effect of nitric acid on increasing oxygen-containing groups on the surface of the active carbon is obvious, and the characteristic wavelength is 3400cm -1 Nearby is the O-H stretching vibration peak, which is reduced after nitric acid modification, which may be due to the O-H groups being lost during nitric acid modification. Therefore, the active functional groups of-COOH and-OH are introduced into the surface of the activated carbon modified by nitric acid, which is beneficial to further widening pore channels, increasing the specific surface area and improving the adsorption performance.
4. ICP characterization
The content of heavy metal elements in the sample 650-1M prepared in example 4 was measured using an ICP spectrometer and compared with untreated raw sludge, and the results are shown in Table 3.
TABLE 3 determination of heavy metal content
| Heavy metals | Cr | Cu | Fe | Mn | Ni |
| Raw sludge (mg/kg) | 3.41 | 24.43 | 2592.78 | 113.83 | 7.89 |
| Sample 650-1M (mg/kg) | - | 0.7 | 36.03 | 1.01 | 1.01 |
As can be seen from Table 3, the heavy metal content in the activated carbon sample 650-1M obtained by carbonization treatment and nitric acid modification is obviously reduced compared with the original sludge before treatment. The reason for this may be that some heavy metal elements dissolved in the alkali solution are washed out during the impregnation and washing with potassium hydroxide solution before carbonization, and are also washed into the solution during the activation and washing with nitric acid after carbonization. In addition, it is also possible that during carbonization of the activated carbon, some heavy metal ions are solidified in the activated carbon so that the heavy metal ions are not dissociated into solution during ICP measurement.
Application test
1. Adsorption and removal performance for Cr (VI) in sewage
Potassium dichromate standard solutions with the concentration of 0.020g/L, 0.042g/L, 0.0525g/L, 0.105g/L and 0.210g/L are prepared respectively. The absorbance of chromium ions at the different concentrations prepared (see Table 4) was measured and an absorbance standard curve was made (see FIG. 6).
TABLE 4 absorbance of different concentrations of Potassium dichromate solutions
| Concentration (g/L) | 0.020 | 0.042 | 0.0525 | 0.105 | 0.210 |
| Absorbance of light | 0.256 | 0.401 | 0.478 | 0.719 | 0.991 |
And (3) carrying out an adsorption experiment on the sample, and measuring the absorbance of the solution according to a standard curve after centrifugal separation.
0.1g/L potassium dichromate solution is prepared, 50mL is taken, 0.1g of active carbon (samples 600-1M, 600-2M, 600-3M, 650-1M, 650-2M, 650-3M, 700-1M, 700-2M and 700-3M prepared in examples 1-9) is respectively added, and after magnetic stirring for 12 hours, the absorbance change before and after measurement is carried out, and the saturated adsorption quantity is calculated. Five parts of the same potassium dichromate solution and activated carbon were taken and magnetically stirred at the same pH (ph=4) at room temperature for 2min, 10min, 20min, 30min, respectively, to measure the absorbance change. The measurement result shows that the absorbance of the potassium dichromate solution does not change obviously when the activated carbon is adsorbed for 2min and 10min and later, and the activated carbon is saturated within 2min and has good performance. The results of the saturated adsorption amount measurement of each of the samples prepared in examples 1 to 9 are shown in Table 5.
TABLE 5 saturated adsorption amount of each sample prepared in examples 1-9
As can be seen from Table 5, at the same carbonization temperature, the saturated adsorption amount of the activated carbon was highest at a 1mol/L potassium hydroxide impregnation concentration, and thus 1mol/L potassium hydroxide was the optimum concentration. This may be due to the collapse of the activated carbon pores at higher potassium hydroxide concentrations and the dissociation of higher potassium ions during the adsorption process, resulting in secondary pollution to the water. When the impregnation concentration of potassium hydroxide is the same, the activated carbon with the carbonization temperature of 650 ℃ has the best effect on the adsorption of heavy metal ions, probably because the lower temperature has no way to well form a good pore structure, while the higher temperature can collapse pore channels, the specific surface area is reduced, and the adsorption performance of the activated carbon is further reduced. Thus, the subsequent studies of the adsorption experimental conditions were all based on 650-1M samples.
(1) Influence of pH on adsorption performance of sludge-based activated carbon
Because the pH has an influence on the existence mode of chromium ions in water, therebyAffecting the saturated adsorption of the active carbon, when the solution is alkalescent, chromium ions mainly adopt CrO4 2- In the form of HCrO4 when the solution is acidic 2- In the form of a gel. CrO4 when the chromium ion content is the same 2- Ratio of oxygen-containing functional groups bound to HCrO 4- The amount of adsorption is reduced by a large amount. In the Cr (VI) adsorption operation, the treatment solution should be maintained in weak acidity to enhance the adsorption capacity of the activated carbon to Cr (VI). Using the sample 650-1M as an example, the saturated adsorption amounts of activated carbon at different pH values were measured according to the above method, the results are shown in FIG. 7, and the specific adsorption results are shown in Table 6.
TABLE 6 influence of different pH on the saturated adsorption
| pH | 3 | 4 | 5 | 6 |
| Saturated adsorption quantity (mg/g) | 38.06 | 40.72 | 37.14 | 31.03 |
As can be seen from fig. 7 and table 6, the activated carbon had the maximum saturated adsorption of chromium ions when the solution was weakly acidic, and the optimum pH was 4. This is because when chromium ions are subjected to acidic conditions, the form of their presence changes, HCrO 4- Takes on the main formWhile the same amount of HCrO 4- The ratio of oxygen-containing functional groups bound to CrO4 2- The saturated adsorption amount of the activated carbon is improved because of the small amount.
(2) Influence of feed ratio on adsorption performance of sludge-based activated carbon
50mL of simulated chromium-containing wastewater with the concentration of 100mg/L is transferred to a plurality of conical flasks, and 0.02g, 0.05g, 0.1g, 0.15g and 0.2g of 650-1M samples are respectively put in the conical flasks, and the saturated adsorption capacity of the activated carbon is measured by the same method, and the results are shown in FIG. 8 and Table 7.
TABLE 7 influence of feed ratio on the adsorption performance of sludge-based activated carbon
| Feed ratio (g active carbon/50 mL chromium-containing wastewater) | 0.02 | 0.05 | 0.1 | 0.15 | 0.2 |
| Saturated adsorption quantity (mg/g) | 9.00 | 17.07 | 35.99 | 38.18 | 38.25 |
As can be seen from FIGS. 8 and 7, in 50mL of simulated chromium-containing wastewater with an initial concentration of 100mg/L, the saturated adsorption amount gradually increased when the amount of activated carbon added was less than 0.15g, and the saturated adsorption amount did not change significantly when it was more than 0.15g, so that the optimal amount of activated carbon sample added was 0.15g and the saturated adsorption amount was 38.18mg/g.
(3) Influence of initial concentration on adsorption performance of sludge-based activated carbon
A simulated chromium-containing wastewater with initial concentration of 200mg/L, 180mg/L, 150mg/L, 120mg/L and 100mg/L was prepared, 0.01g of 650-1M sample was added, absorbance change was measured after adsorption for 30min at normal temperature (25 ℃) and the same rotational speed, and saturated adsorption amount of activated carbon was measured by the same method as described above, and the results are shown in FIG. 9 and Table 8.
TABLE 8 influence of initial concentration on saturated adsorption quantity
| Initial concentration (mg/L) | 190 | 160 | 130 | 100 | 70 |
| Saturated adsorption quantity (mg/g) | 32.68 | 32.57 | 34.38 | 35.41 | 29.14 |
As can be seen from FIG. 9 and Table 8, the saturated adsorption amount gradually increased when the initial concentration was from 190mg/L to 100mg/L, with 130mg/L and 100mg/L being larger, and the saturated adsorption amount of activated carbon significantly decreased when the concentration was lower. Thus, the initial concentration may be 130mg/L.
2. Adsorption and removal performance for methyl orange in sewage
Methyl orange standard solutions with concentrations of 1mg/L, 2mg/L, 3mg/L, 4mg/L and 5mg/L respectively were prepared and absorbance was measured (see Table 9), and absorbance standard curves thereof were made (see FIG. 10).
TABLE 9 absorbance of different concentrations of methyl orange standard solution
| Concentration (mg/L) | 1.00 | 2.00 | 3.00 | 4.00 | 5.00 |
| Absorbance of light | 0.10 | 0.19 | 0.26 | 0.37 | 0.44 |
And (3) carrying out an adsorption experiment on the sample, and measuring the absorbance of the solution according to a standard curve after centrifugal separation.
(1) Influence of feed ratio on adsorption performance of sludge-based activated carbon
A14 mg/L methyl orange standard solution was prepared, five 50mL methyl orange standard solutions were weighed, 0.02g, 0.04g, 0.06g, 0.08g and 0.1g of 650-1M samples were respectively put into the solution, and the solution was magnetically stirred under the same conditions for 5 hours, and the saturated adsorption capacity of activated carbon was measured by the same method as described above, and the results are shown in FIG. 11 and Table 10.
TABLE 10 influence of feed ratio on adsorption performance of sludge-based activated carbon
| Feed ratio (g active carbon/50 mL methyl orange wastewater) | 0.02 | 0.04 | 0.06 | 0.08 | 0.1 |
| Saturated adsorption quantity (mg/g) | 6.62 | 9.39 | 9.80 | 9.77 | 9.82 |
As can be seen from FIG. 11 and Table 10, the amount of activated carbon added was gradually increased from 0.02g to 0.06g, whereas the change was not significant when more than 0.06g, so that the adsorption effect was optimal when 1.2g of activated carbon was added to 1L of 14mg/L of methyl orange-containing wastewater, and the saturated adsorption amount could reach 9.82mg/g.
(2) Influence of initial concentration on adsorption performance of sludge-based activated carbon
Methyl orange standard solutions with initial concentrations of 5mg/L, 10mg/L, 15mg/L, 20mg/L, 25mg/L and 30mg/L are prepared, 0.05g of sample 650-1M is added, magnetic stirring is carried out for 5 hours under the same conditions, the saturated adsorption quantity of the activated carbon is measured by the same method, and the measurement results are shown in FIG. 12 and Table 11.
TABLE 11 influence of initial concentration on saturated adsorption quantity
As can be seen from fig. 12 and table 11, the saturated adsorption amount of activated carbon is larger as the initial concentration is larger, but as the concentration is increased, the increase thereof becomes gentle when the initial concentration exceeds 25mg/L. Thus, the optimal starting concentration of methyl orange is 25mg/L.
(3) Adsorption amount changes with time
The concentration of the methyl orange solution was set to 14mg/L, and 0.06g of sample 650-1M was added to 50mL of the methyl orange solution, and the result of the adsorption amount of sample 650-1M to methyl orange over time was shown in FIG. 13. As can be seen from fig. 13, the adsorption of the activated carbon to the methyl orange goes through a process of fast and slow, and after 20min, the adsorption effect is obviously slowed down, which may be because the methyl orange content in water is higher when the activated carbon adsorption starts, and the methyl orange content in water is reduced when the activated carbon is adsorbed to 20min, so that the adsorption of the activated carbon to the activated carbon is slowed down.
3. Adsorption and removal performance for COD in sewage
Taking 0.1g of activated carbon sample, adding 50mL of simulated wastewater (COD in the initial wastewater sample is about 1000-1200 and is diluted 10 times for use) into the sample, stirring the sample for 12h at normal temperature (25 ℃) by using a magnetic stirrer, measuring the COD content in the water body by using a Shanghai Lianhua technology COD rapid tester, and calculating the COD removal rate.
(1) Influence of modifier on adsorption performance of activated carbon
The removal results of COD in wastewater by the sludge-based activated carbon prepared in example 4 and comparative examples 1 and 2 were measured and are shown in Table 12.
TABLE 12 COD removal results
| Modifying agent | Comparative example 1 | Example 4 | Comparative example 2 |
| Removal rate% | 31.47 | 84.29 | 74.92 |
As can be seen from table 12, the phosphoric acid modification (comparative example 1) did not improve much the adsorption effect on activated carbon, whereas the nitric acid (example 4) and potassium hydroxide (comparative example 2) improved much the adsorption effect, probably because the strong acid and strong base modified the activated carbon channels and grafted the oxygen-containing functional groups to the activated carbon surface more easily.
(2) Influence of feed ratio on adsorption performance of activated carbon
Samples 650-1M with different qualities are put into 50mL of simulated sewage, magnetically stirred for 12 hours at normal temperature (25 ℃), and COD removal rates in the sewage are measured according to different put amounts, and the result is shown in FIG. 14.
As can be seen from FIG. 14, when the amount of the activated carbon fed was not more than 0.08g, the COD removal rate varied significantly, whereas when the amount of the activated carbon fed was more than 0.08g, the COD removal rate varied slowly. Thus, the optimal dosage of activated carbon is 0.08g.
(3) Influence of adsorption time on adsorption performance of activated carbon
0.08g of 650-1M sample was added to 50mL of sewage, and the removal rate of COD in the sewage at different adsorption times was measured, and the result is shown in FIG. 15. As can be seen from FIG. 15, after the adsorption time reached 50min, the saturated adsorption amount change curve of the activated carbon was substantially retarded without significant change, and thus the saturated adsorption time was found to be 50min.
The present application is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present application are intended to be included in the scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims (9)
1. The preparation method of the sludge-based activated carbon is characterized by comprising the following steps of:
drying and crushing sludge, uniformly mixing the sludge with peanut shells to obtain a mixture, pre-carbonizing the mixture, soaking the pre-carbonized mixture in KOH solution, washing the soaked mixture, carbonizing to obtain carbonized chemical sludge, soaking the carbonized chemical sludge with nitric acid, washing with water, filtering, drying and grinding to obtain the sludge-based activated carbon.
2. The method for preparing sludge-based activated carbon according to claim 1, wherein the mass ratio of the sludge to the peanut shell is 3:1.
3. The method for preparing sludge-based activated carbon according to claim 1, wherein the temperature of the pre-carbonization treatment is 200 ℃, the constant temperature is 2 hours, and the temperature rising rate is 5 ℃/min.
4. The method for preparing sludge-based activated carbon according to claim 1, wherein the concentration of the KOH solution is 1-3mol/L, and the time of immersing in the KOH solution is 24 hours.
5. The method for preparing sludge-based activated carbon according to claim 1, wherein the carbonization treatment is carried out at 600 ℃ to 700 ℃ for 2 hours at a constant temperature and at a temperature rising rate of 5 ℃/min.
6. The method for preparing sludge-based activated carbon according to claim 1, wherein the concentration of nitric acid is 1mol/L, and the time of adding nitric acid for impregnation is 12 hours.
7. A sludge-based activated carbon prepared by the method of any one of claims 1-6.
8. The use of the sludge-based activated carbon of claim 7 in sewage treatment.
9. The use according to claim 8, characterized in that the sludge-based activated carbon is used for adsorbing Cr (vi), methyl orange and COD in sewage.
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| CN108033448A (en) * | 2018-01-31 | 2018-05-15 | 西南石油大学 | A kind of coconut husk-sludge composite activated carbon and its preparation method and application |
| CN116002682A (en) * | 2022-12-21 | 2023-04-25 | 湖北省长江水生态研究院有限责任公司 | Method for preparing formed active carbon by taking sludge as raw material |
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| CN108033448A (en) * | 2018-01-31 | 2018-05-15 | 西南石油大学 | A kind of coconut husk-sludge composite activated carbon and its preparation method and application |
| CN116002682A (en) * | 2022-12-21 | 2023-04-25 | 湖北省长江水生态研究院有限责任公司 | Method for preparing formed active carbon by taking sludge as raw material |
Non-Patent Citations (2)
| Title |
|---|
| 辛莹娟 等: "有机/无机酸改性兰炭基活性炭及其对焦化废水的吸附研究", 《洁净煤技术》, no. 4, pages 196 - 202 * |
| 黄河;刘洪波;高赛赛;罗森;李永平;: "酸改性活性炭在重金属与氨氮废水处理中的应用", 四川环境, no. 05, pages 1 * |
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