CN115536852B - Application of chitosan-based flocculant - Google Patents
Application of chitosan-based flocculant Download PDFInfo
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- CN115536852B CN115536852B CN202211325791.6A CN202211325791A CN115536852B CN 115536852 B CN115536852 B CN 115536852B CN 202211325791 A CN202211325791 A CN 202211325791A CN 115536852 B CN115536852 B CN 115536852B
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- based flocculant
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- 229920001661 Chitosan Polymers 0.000 title claims abstract description 155
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 23
- 238000004042 decolorization Methods 0.000 claims abstract description 20
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 63
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 48
- 238000006243 chemical reaction Methods 0.000 claims description 36
- 238000003756 stirring Methods 0.000 claims description 25
- WAMWSIDTKSNDCU-ZETCQYMHSA-N (2s)-2-azaniumyl-2-cyclohexylacetate Chemical compound OC(=O)[C@@H](N)C1CCCCC1 WAMWSIDTKSNDCU-ZETCQYMHSA-N 0.000 claims description 24
- CWERGRDVMFNCDR-UHFFFAOYSA-N thioglycolic acid Chemical compound OC(=O)CS CWERGRDVMFNCDR-UHFFFAOYSA-N 0.000 claims description 18
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 16
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 15
- IQFVPQOLBLOTPF-HKXUKFGYSA-L congo red Chemical compound [Na+].[Na+].C1=CC=CC2=C(N)C(/N=N/C3=CC=C(C=C3)C3=CC=C(C=C3)/N=N/C3=C(C4=CC=CC=C4C(=C3)S([O-])(=O)=O)N)=CC(S([O-])(=O)=O)=C21 IQFVPQOLBLOTPF-HKXUKFGYSA-L 0.000 claims description 15
- LMDZBCPBFSXMTL-UHFFFAOYSA-N 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide Substances CCN=C=NCCCN(C)C LMDZBCPBFSXMTL-UHFFFAOYSA-N 0.000 claims description 14
- FPQQSJJWHUJYPU-UHFFFAOYSA-N 3-(dimethylamino)propyliminomethylidene-ethylazanium;chloride Chemical compound Cl.CCN=C=NCCCN(C)C FPQQSJJWHUJYPU-UHFFFAOYSA-N 0.000 claims description 14
- VHYFNPMBLIVWCW-UHFFFAOYSA-N 4-Dimethylaminopyridine Chemical compound CN(C)C1=CC=NC=C1 VHYFNPMBLIVWCW-UHFFFAOYSA-N 0.000 claims description 14
- 229940088644 n,n-dimethylacrylamide Drugs 0.000 claims description 13
- YLGYACDQVQQZSW-UHFFFAOYSA-N n,n-dimethylprop-2-enamide Chemical compound CN(C)C(=O)C=C YLGYACDQVQQZSW-UHFFFAOYSA-N 0.000 claims description 13
- 238000002360 preparation method Methods 0.000 claims description 13
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 12
- 239000007795 chemical reaction product Substances 0.000 claims description 12
- 239000000839 emulsion Substances 0.000 claims description 11
- 239000003999 initiator Substances 0.000 claims description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000008367 deionised water Substances 0.000 claims description 8
- 229910021641 deionized water Inorganic materials 0.000 claims description 8
- 230000001376 precipitating effect Effects 0.000 claims description 8
- NQTADLQHYWFPDB-UHFFFAOYSA-N N-Hydroxysuccinimide Chemical compound ON1C(=O)CCC1=O NQTADLQHYWFPDB-UHFFFAOYSA-N 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- JRMUNVKIHCOMHV-UHFFFAOYSA-M tetrabutylammonium bromide Chemical compound [Br-].CCCC[N+](CCCC)(CCCC)CCCC JRMUNVKIHCOMHV-UHFFFAOYSA-M 0.000 claims description 7
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 238000010907 mechanical stirring Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- CQPFMGBJSMSXLP-UHFFFAOYSA-M acid orange 7 Chemical compound [Na+].OC1=CC=C2C=CC=CC2=C1N=NC1=CC=C(S([O-])(=O)=O)C=C1 CQPFMGBJSMSXLP-UHFFFAOYSA-M 0.000 claims description 5
- ZQWICJYATMSSSD-UHFFFAOYSA-M chembl2028584 Chemical compound [Na+].C1=CC=C2C(N=NC3=C4C=CC=CC4=CC=C3O)=C(O)C=C(S([O-])(=O)=O)C2=C1 ZQWICJYATMSSSD-UHFFFAOYSA-M 0.000 claims description 4
- 238000000502 dialysis Methods 0.000 claims description 4
- GNBHRKFJIUUOQI-UHFFFAOYSA-N fluorescein Chemical compound O1C(=O)C2=CC=CC=C2C21C1=CC=C(O)C=C1OC1=CC(O)=CC=C21 GNBHRKFJIUUOQI-UHFFFAOYSA-N 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 239000000344 soap Substances 0.000 claims description 2
- 238000001291 vacuum drying Methods 0.000 claims description 2
- KZMRYBLIGYQPPP-UHFFFAOYSA-O [4-[(2-chlorophenyl)-[4-[ethyl-[(3-sulfophenyl)methyl]amino]phenyl]methylidene]cyclohexa-2,5-dien-1-ylidene]-ethyl-[(3-sulfophenyl)methyl]azanium Chemical compound C=1C=C(C(=C2C=CC(C=C2)=[N+](CC)CC=2C=C(C=CC=2)S(O)(=O)=O)C=2C(=CC=CC=2)Cl)C=CC=1N(CC)CC1=CC=CC(S(O)(=O)=O)=C1 KZMRYBLIGYQPPP-UHFFFAOYSA-O 0.000 claims 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims 1
- 229910052804 chromium Inorganic materials 0.000 claims 1
- 239000011651 chromium Substances 0.000 claims 1
- FPVGTPBMTFTMRT-UHFFFAOYSA-L disodium;2-amino-5-[(4-sulfonatophenyl)diazenyl]benzenesulfonate Chemical compound [Na+].[Na+].C1=C(S([O-])(=O)=O)C(N)=CC=C1N=NC1=CC=C(S([O-])(=O)=O)C=C1 FPVGTPBMTFTMRT-UHFFFAOYSA-L 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 21
- 239000008394 flocculating agent Substances 0.000 abstract description 20
- 239000002184 metal Substances 0.000 abstract description 4
- 150000003839 salts Chemical class 0.000 abstract description 4
- 230000009471 action Effects 0.000 abstract description 2
- 230000005484 gravity Effects 0.000 abstract description 2
- 229920000642 polymer Polymers 0.000 abstract description 2
- 239000000975 dye Substances 0.000 description 31
- 239000002351 wastewater Substances 0.000 description 14
- 238000000034 method Methods 0.000 description 9
- 238000010521 absorption reaction Methods 0.000 description 8
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- 230000008901 benefit Effects 0.000 description 6
- 229910001410 inorganic ion Inorganic materials 0.000 description 6
- 238000004043 dyeing Methods 0.000 description 5
- 239000000706 filtrate Substances 0.000 description 5
- 238000007639 printing Methods 0.000 description 5
- 239000006228 supernatant Substances 0.000 description 5
- 238000000870 ultraviolet spectroscopy Methods 0.000 description 5
- 101150038588 CHRNB1 gene Proteins 0.000 description 4
- 150000001408 amides Chemical class 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 238000001878 scanning electron micrograph Methods 0.000 description 4
- KZMRYBLIGYQPPP-UHFFFAOYSA-N 3-[[[4-[(2-chlorophenyl)-[4-[ethyl-[(3-sulfonatophenyl)methyl]azaniumylidene]cyclohexa-2,5-dien-1-ylidene]methyl]phenyl]-ethylazaniumyl]methyl]benzenesulfonate Chemical compound C=1C=C(C(=C2C=CC(C=C2)=[N+](CC)CC=2C=C(C=CC=2)S([O-])(=O)=O)C=2C(=CC=CC=2)Cl)C=CC=1[NH+](CC)CC1=CC=CC(S([O-])(=O)=O)=C1 KZMRYBLIGYQPPP-UHFFFAOYSA-N 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000006065 biodegradation reaction Methods 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 238000002329 infrared spectrum Methods 0.000 description 2
- 239000004342 Benzoyl peroxide Substances 0.000 description 1
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 description 1
- IQFVPQOLBLOTPF-UHFFFAOYSA-L Congo Red Chemical compound [Na+].[Na+].C1=CC=CC2=C(N)C(N=NC3=CC=C(C=C3)C3=CC=C(C=C3)N=NC3=C(C4=CC=CC=C4C(=C3)S([O-])(=O)=O)N)=CC(S([O-])(=O)=O)=C21 IQFVPQOLBLOTPF-UHFFFAOYSA-L 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 125000003368 amide group Chemical group 0.000 description 1
- 235000019400 benzoyl peroxide Nutrition 0.000 description 1
- 230000005591 charge neutralization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 231100000086 high toxicity Toxicity 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000005180 public health Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G81/00—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers
- C08G81/02—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers at least one of the polymers being obtained by reactions involving only carbon-to-carbon unsaturated bonds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
- C08B37/0006—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid
- C08B37/0024—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid beta-D-Glucans; (beta-1,3)-D-Glucans, e.g. paramylon, coriolan, sclerotan, pachyman, callose, scleroglucan, schizophyllan, laminaran, lentinan or curdlan; (beta-1,6)-D-Glucans, e.g. pustulan; (beta-1,4)-D-Glucans; (beta-1,3)(beta-1,4)-D-Glucans, e.g. lichenan; Derivatives thereof
- C08B37/0027—2-Acetamido-2-deoxy-beta-glucans; Derivatives thereof
- C08B37/003—Chitin, i.e. 2-acetamido-2-deoxy-(beta-1,4)-D-glucan or N-acetyl-beta-1,4-D-glucosamine; Chitosan, i.e. deacetylated product of chitin or (beta-1,4)-D-glucosamine; Derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F120/52—Amides or imides
- C08F120/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Molecular Biology (AREA)
- General Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
An application of chitosan-based flocculant relates to an application of a polymer-based flocculant. The invention aims to solve the problems that the decolorization effect is general, the settling time of the floccules is long and the floccules are sometimes required to be used in combination with a metal salt flocculant when the traditional organic polymeric flocculant is used for decolorizing the floccules. A chitosan-based flocculant is applied to dye decolorization; the chitosan-based flocculant is a comb-shaped chitosan-based flocculant or a chain-shaped chitosan-based flocculant. In the invention, the two flocculants show different structures due to different molecular structures, but the flocculants can be rapidly separated from water and settle under the action of gravity due to certain hydrophobicity, so that the settling performance is better and the decolorizing effect is better.
Description
Technical Field
The invention relates to application of a polymer-based flocculant.
Background
Textile industry is one of the most serious industries of China. The printing and dyeing wastewater produced in the production process has the characteristics of large volume, high chromaticity, complex components, high toxicity, difficult biodegradation and the like. The release of dyes into the ecosystem will threaten biodiversity and public health. In addition, the shortage of water resources in China is increasingly serious. Therefore, it is particularly important to treat the printing and dyeing wastewater by using an economical and efficient method.
Methods currently used for treating dye wastewater include adsorption, coagulation, oxidation, membrane, electrolytic and biodegradation methods. Among these technologies, the coagulation sedimentation method has outstanding advantages in large-scale treatment of printing and dyeing wastewater due to simple process flow, low equipment investment, small occupied area and high efficiency. The traditional metal salt flocculant has the defects of large useful amount, residual metal ions in treated water and the like. Thus, the development of flocculants is now tending towards organic polymeric flocculants and bioflocculants. The organic polymeric flocculant has the advantages of small dosage, high efficiency, small influence of coexisting inorganic ions and pH value, low sludge yield and the like, and is widely applied.
However, at present, when an organic polymeric flocculant is used for a decolorizing flocculant, the problem that the decolorizing effect is general, the settling time of the flocculant is long and the flocculant and a metal salt flocculant are sometimes required to be used in a combined way exists.
Disclosure of Invention
The invention aims to solve the problems that the decolorization effect is general, the settling time of the floccules is long and the floccules are sometimes required to be used in combination with a metal salt flocculant when the traditional organic polymeric flocculant is used for decolorizing the flocculant, and provides the application of the chitosan-based flocculant.
A chitosan-based flocculant is applied to dye decolorization; the chitosan-based flocculant is a comb-shaped chitosan-based flocculant or a chain-shaped chitosan-based flocculant.
The preparation method of the comb-shaped chitosan-based flocculant is completed according to the following steps:
1. Preparation of a polydimethyl acrylamide solution:
① . Dissolving thioglycollic acid into toluene with oxygen removed to obtain thioglycollic acid toluene solution;
② . Adding an initiator into a thioglycollic acid toluene solution with the temperature of 60-90 ℃ and stirring for dissolution to obtain a reaction system;
③ . Dropwise adding N, N-dimethylacrylamide into a reaction system, and stirring and reacting under the condition of nitrogen atmosphere and 60-90 ℃ to obtain a polydimethyl acrylamide solution;
2. grafting reaction:
① . Dissolving chitosan in dilute acid, and then adjusting the pH value to 6 by using NaOH solution to obtain chitosan solution;
② . Adding tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride into a polydimethyl acrylamide solution, and uniformly stirring under the nitrogen atmosphere to obtain a reaction solution;
③ . Adding chitosan solution into the reaction solution, and stirring under nitrogen atmosphere at room temperature to obtain an off-white emulsion solution;
④ . And (3) dialyzing the off-white emulsion solution by using deionized water as a dialyzate, precipitating the solution by using acetone, washing by using absolute ethyl alcohol, and drying in vacuum to obtain the comb-shaped chitosan-based flocculant.
The preparation method of the chain chitosan-based flocculant is completed according to the following steps:
1. dissolving 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride in water to obtain a solution A;
2. Dissolving chitosan in dilute acid, and then adjusting the pH value to 8 by using NaOH solution to obtain chitosan solution;
3. Dissolving L-cyclohexylglycine in dilute hydrochloric acid with the mass fraction of 0.2% -0.3%, and then adjusting the pH value to 2-2.5 by using NaOH solution to obtain L-cyclohexylglycine solution;
4. Adding chitosan solution into the solution A, and then dropwise adding L-cyclohexylglycine solution to obtain a reaction system; mechanically stirring the reaction system at room temperature under nitrogen atmosphere to obtain a reaction product;
5. the method comprises the steps of firstly dialyzing a reaction product by using dilute hydrochloric acid, then dialyzing the reaction product by using deionized water, precipitating by using acetone, washing by using absolute ethyl alcohol and drying in vacuum to obtain the chain chitosan-based flocculant.
Compared with the prior art, the chitosan-based flocculant prepared by the invention has the following advantages:
1. The comb-shaped chitosan-based flocculant and the chain-shaped chitosan-based flocculant synthesized by the invention have loose and porous textures, have larger specific surface area, have remarkable advantages in the aspect of adsorption bridging, further improve zeta potential of the flocculant obtained after chitosan grafting, enhance charge neutralization effect between the flocculant and dye, realize efficient removal of the dye under smaller dosage, and save cost;
2. The average water contact angles of the comb-shaped and chain-shaped polysaccharide-based flocculants are 40.60 degrees and 64.82 degrees respectively, and the enhancement of hydrophobicity ensures that the flocculants and dye molecules have stronger hydrophobic effect, so that the flocculant has excellent decolorizing capacity, and the maximum decolorizing rate can reach 99 percent;
3. The chitosan-based flocculant synthesized by the invention has wide application range, can effectively decolorize dye wastewater with pH value in the range of 2-9, and meets the requirements of various printing and dyeing wastewater; meanwhile, the dye has better stability, and the decoloring effect is not influenced by the concentration of dye, coexisting inorganic ions and turbidity;
4. In the invention, the two flocculants show different structures due to different molecular structures, but the flocculants can be rapidly separated from water and settle under the action of gravity due to certain hydrophobicity, so that the settling performance is better.
5. The invention adopts the thermal decomposition type initiator, has low requirements on preparation conditions and simple operation, and the chitosan-based flocculant synthesized by the invention has wide application prospect in the aspect of large-scale treatment of printing and dyeing wastewater; meanwhile, the invention also provides a meaningful reference for the design and development of the high-efficiency decolorizing flocculant.
Drawings
FIG. 1 is an SEM image of a comb-type chitosan-based flocculant prepared in example 1;
FIG. 2 is an SEM image of a chain chitosan-based flocculant prepared in example 2;
FIG. 3 is a schematic view of the water contact angle of the comb-type chitosan-based flocculant prepared in example 1;
FIG. 4 is a schematic view of the water contact angle of the chain-type chitosan-based flocculant prepared in example 2;
FIG. 5 is a schematic representation of zeta potential of chitosan-based flocculants at different pH's;
FIG. 6 is an infrared spectrum of a chitosan-based flocculant;
FIG. 7 is an X-ray photoelectron spectrum of a chitosan-based flocculant;
FIG. 8 is a graph showing the removal of Congo red at various dosage levels of a chitosan-based flocculant;
FIG. 9 shows the removal of acid chrome blue with different dosage of chitosan-based flocculant;
FIG. 10 shows the removal of alizarin green with different amounts of chitosan-based flocculant;
FIG. 11 shows the removal of acid orange with different dosage amounts of chitosan-based flocculant;
FIG. 12 shows the removal of soap yellow with different amounts of chitosan-based flocculant;
FIG. 13 is a graph comparing the decolorizing effect of chitosan-based flocculant on Congo red at different pH values;
FIG. 14 is a graph comparing decolorizing effects of chitosan-based flocculants at different turbidity;
FIG. 15 is a graph showing the comparison of decolorizing effect of chitosan-based flocculant under the coexistence of different inorganic ions;
FIG. 16 is a graph of optimum dosage of chitosan-based flocculant versus initial Congo red concentration versus decolorizing effect of flocculant at different initial Congo red concentrations.
Detailed Description
The following examples further illustrate the invention but are not to be construed as limiting the invention. Modifications and substitutions to methods, procedures, or conditions of the present invention without departing from the spirit of the invention are intended to be within the scope of the present invention.
The first embodiment is as follows: the chitosan-based flocculant is applied to dye decolorization; the chitosan-based flocculant is a comb-shaped chitosan-based flocculant or a chain-shaped chitosan-based flocculant.
The second embodiment is as follows: the present embodiment differs from the specific embodiment in that: the dye is congo red, acid chrome blue, alizarin green, acid orange or soap yellow. The other steps are the same as in the first embodiment.
And a third specific embodiment: this embodiment differs from the first or second embodiment in that: the decolorization rate of the dye can reach 99 percent. The other steps are the same as those of the first or second embodiment.
The specific embodiment IV is as follows: one difference between this embodiment and the first to third embodiments is that: the preparation method of the comb-shaped chitosan-based flocculant is completed according to the following steps:
1. Preparation of a polydimethyl acrylamide solution:
① . Dissolving thioglycollic acid into toluene with oxygen removed to obtain thioglycollic acid toluene solution;
② . Adding an initiator into a thioglycollic acid toluene solution with the temperature of 60-90 ℃ and stirring for dissolution to obtain a reaction system;
③ . Dropwise adding N, N-dimethylacrylamide into a reaction system, and stirring and reacting under the condition of nitrogen atmosphere and 60-90 ℃ to obtain a polydimethyl acrylamide solution;
2. grafting reaction:
① . Dissolving chitosan in dilute acid, and then adjusting the pH value to 6 by using NaOH solution to obtain chitosan solution;
② . Adding tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride into a polydimethyl acrylamide solution, and uniformly stirring under the nitrogen atmosphere to obtain a reaction solution;
③ . Adding chitosan solution into the reaction solution, and stirring under nitrogen atmosphere at room temperature to obtain an off-white emulsion solution;
④ . And (3) dialyzing the off-white emulsion solution by using deionized water as a dialyzate, precipitating the solution by using acetone, washing by using absolute ethyl alcohol, and drying in vacuum to obtain the comb-shaped chitosan-based flocculant. The other steps are the same as those of the first to third embodiments.
Fifth embodiment: one to four differences between the present embodiment and the specific embodiment are: the mass fraction of the thioglycollic acid toluene solution in the step one ① is 2% -4%; the toluene with oxygen removed in the first ① step is that nitrogen is continuously introduced into the toluene for 5 to 10 minutes; the initiator in the first ② is benzoyl peroxide or azobisisobutyronitrile; the molar ratio of the N, N-dimethylacrylamide, the thioglycollic acid and the initiator in the step one ③ is (220-270): (20-30): (1-3); the stirring reaction time in the step one ③ is 2-6 h. Other steps are the same as those of the first to fourth embodiments.
Specific embodiment six: the present embodiment differs from the first to fifth embodiments in that: the dilute acid in the second ① step is dilute hydrochloric acid or dilute acetic acid, and the mass fraction is 0.5% -1%; the mass fraction of the chitosan solution in the second ① is 3% -5%; the molar ratio of tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step two ② to N, N-dimethylacrylamide described in step one ③ is 25:1:1:1; the stirring time in the second ③ step is 8-10 h, and the stirring speed is 200-400 r/min; the molar ratio of chitosan to N, N-dimethylacrylamide in the off-white emulsion solution in the step two ③ is 1:10; the dialysis time in the second ④ is 9-12 hours. Other steps are the same as those of the first to fifth embodiments.
Seventh embodiment: one difference between the present embodiment and the first to sixth embodiments is that: the preparation method of the chain chitosan-based flocculant is completed according to the following steps:
1. dissolving 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride in water to obtain a solution A;
2. Dissolving chitosan in dilute acid, and then adjusting the pH value to 8 by using NaOH solution to obtain chitosan solution;
3. Dissolving L-cyclohexylglycine in dilute hydrochloric acid with the mass fraction of 0.2% -0.3%, and then adjusting the pH value to 2-2.5 by using NaOH solution to obtain L-cyclohexylglycine solution;
4. Adding chitosan solution into the solution A, and then dropwise adding L-cyclohexylglycine solution to obtain a reaction system; mechanically stirring the reaction system at room temperature under nitrogen atmosphere to obtain a reaction product;
5. The method comprises the steps of firstly dialyzing a reaction product by using dilute hydrochloric acid, then dialyzing the reaction product by using deionized water, precipitating by using acetone, washing by using absolute ethyl alcohol and drying in vacuum to obtain the chain chitosan-based flocculant. Other steps are the same as those of embodiments one to six.
Eighth embodiment: one difference between the present embodiment and the first to seventh embodiments is that: the molar ratio of 4-dimethylaminopyridine to 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step one is 1:3; the mass fraction of the NaOH solution in the second ① is 0.5% -2%; the dilute acid in the second ① step is dilute hydrochloric acid or dilute acetic acid, and the mass fraction is 0.5% -1%; the mass fraction of the chitosan solution in the step two ① is 2% -3%. The other steps are the same as those of embodiments one to seven.
Detailed description nine: one of the differences between this embodiment and the first to eighth embodiments is: the mass fraction of the L-cyclohexyl glycine solution in the third step is 1% -1.2%; the mass fraction of the NaOH solution in the third step is 0.5% -2%; the molar ratio of chitosan to L-cyclohexylglycine in the reaction system in the fourth step is 3:2; the molar ratio of the L-cyclohexylglycine to the L-cyclohexylglycine in the reaction system in the fourth step is 4:1; and in the fourth step, the mechanical stirring time is 8-10 h, and the mechanical stirring speed is 200-400 r/min. Other steps are the same as those of embodiments one to eight.
Detailed description ten: the present embodiment differs from the first to ninth embodiments in that: the dialysis time in the fifth step is 9-12 h; and step five, the pH value of the dilute hydrochloric acid is 2-2.2. The other steps are the same as those of embodiments one to nine.
The following examples are used to verify the benefits of the present invention:
Example 1: a chitosan-based flocculant is applied to dye decolorization; the chitosan-based flocculant is a comb-shaped chitosan-based flocculant;
the preparation method of the comb-shaped chitosan-based flocculant is completed according to the following steps:
1. Preparation of a polydimethyl acrylamide solution:
① . Continuously introducing nitrogen into toluene for 10min to obtain toluene with oxygen removed; dissolving thioglycollic acid into toluene with oxygen removed to obtain thioglycollic acid toluene solution;
The mass fraction of the thioglycollic acid toluene solution in the step one ① is 3%;
② . Adding an initiator into a thioglycollic acid toluene solution with the temperature of 80 ℃, and stirring and dissolving to obtain a reaction system;
The initiator in the first ② is azobisisobutyronitrile;
③ . Dropwise adding N, N-dimethylacrylamide into a reaction system, and stirring and reacting for 4 hours under the condition of nitrogen atmosphere and 80 ℃ to obtain a polydimethyl acrylamide solution;
the molar ratio of N, N-dimethylacrylamide, thioglycollic acid and initiator in step one ③ is 250:25:2;
2. grafting reaction:
① . Dissolving chitosan in 0.5% of dilute hydrochloric acid by mass fraction, and adjusting the pH value to 6 by using 1% of NaOH solution by mass fraction to obtain chitosan solution;
the mass fraction of the chitosan solution in the second ① is 4%;
② . Adding tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride into a polydimethyl acrylamide solution, and uniformly stirring under the nitrogen atmosphere to obtain a reaction solution;
The molar ratio of tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step two ② to N, N-dimethylacrylamide described in step one ③ is 25:1:1:1;
③ . Adding chitosan solution into the reaction solution, and stirring for 8 hours under nitrogen atmosphere and room temperature to obtain an off-white emulsion solution;
The stirring speed in the second ③ step is 300r/min;
The molar ratio of chitosan to N, N-dimethylacrylamide in the off-white emulsion solution in the step two ③ is 1:10;
④ . Dialyzing the off-white emulsion solution by using deionized water as a dialyzate, precipitating the solution by using acetone, cleaning by using absolute ethyl alcohol, and vacuum drying for 24 hours at 60 ℃ to obtain the comb-shaped chitosan-based flocculant;
The dialysis time described in step two ④ was 12 hours, with dialysate changed every 3 hours.
The reaction formula for preparing the comb-chitosan-based flocculant in example 1 is as follows:
example 2: a chitosan-based flocculant is applied to dye decolorization; the chitosan-based flocculant is a chain chitosan-based flocculant;
the preparation method of the chain chitosan-based flocculant is completed according to the following steps:
1. dissolving 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride in water to obtain a solution A;
the molar ratio of 4-dimethylaminopyridine to 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step one is 1:3;
2. dissolving chitosan in 0.5 mass percent of dilute hydrochloric acid, and then adjusting the pH value to 8 by using a NaOH solution to obtain a chitosan solution;
The mass fraction of the NaOH solution in the second ① is 1%;
the mass fraction of the chitosan solution in the second ① is 2%;
3. dissolving L-cyclohexylglycine in 0.2% of dilute hydrochloric acid by mass fraction, and regulating the pH value to 2.2 by using NaOH solution to obtain L-cyclohexylglycine solution;
The mass fraction of the L-cyclohexyl glycine solution in the step three is 1.2%;
4. Adding chitosan solution into the solution A, and then dropwise adding L-cyclohexylglycine solution to obtain a reaction system; mechanically stirring the reaction system at room temperature under nitrogen atmosphere to obtain a reaction product;
the molar ratio of chitosan to L-cyclohexylglycine in the reaction system in the fourth step is 3:2;
the molar ratio of the L-cyclohexylglycine to the L-cyclohexylglycine in the reaction system in the fourth step is 4:1;
in the fourth step, the mechanical stirring time is 8 hours, and the mechanical stirring speed is 300r/min;
5. Firstly, dialyzing a reaction product for 6 hours by using dilute hydrochloric acid with the pH value of 2.2, dialyzing the reaction product for 6 hours by using deionized water, precipitating by using acetone, washing by using absolute ethyl alcohol, and drying in vacuum at 60 ℃ for 24 hours to obtain a chain chitosan-based flocculant;
And in the fifth step, the dialysate is replaced every 3 hours.
The reaction scheme for preparing the chain chitosan-based flocculant in example 2 is as follows:
FIG. 1 is an SEM image of a comb-type chitosan-based flocculant prepared in example 1;
FIG. 2 is an SEM image of a chain chitosan-based flocculant prepared in example 2;
as can be seen from fig. 1-2, the textures of the comb-shaped chitosan-based flocculant and the chain-shaped chitosan-based flocculant are loose and porous, and the comb-shaped chitosan-based flocculant has remarkable advantages in adsorption bridging.
FIG. 3 is a schematic view of the water contact angle of the comb-type chitosan-based flocculant prepared in example 1;
FIG. 4 is a schematic view of the water contact angle of the chain-type chitosan-based flocculant prepared in example 2;
As can be seen from fig. 3 to 4: the comb-type chitosan-based flocculant prepared in example 1 had a water contact angle of 40.60 °, the chain-type chitosan-based flocculant prepared in example 2 had a water contact angle of 64.82 °, and the increase in hydrophobicity enhanced the hydrophobic effect between the flocculant and the dye.
FIG. 5 is a schematic representation of zeta potential of chitosan-based flocculants at different pH's.
FIG. 6 is an infrared spectrum of a chitosan-based flocculant;
As can be seen from fig. 6: 3370cm -1 is a multiple absorption peak of chitosan in which the absorption peaks of stretching vibration of-OH and-NH 2 overlap and broaden, the in-plane bending vibration of-NH 2 is 1600cm -1, and the strong absorption peak of 1085cm -1 corresponds to the stretching vibration absorption peak of glycosidic bond. The comb chitosan-based flocculant produced amide i absorption peaks due to c=o stretching vibration in amide groups and amide ii absorption peaks due to N-H bending vibration and C-N stretching vibration at 1629cm -1 and 1555cm -1. The new peak generated at 1634cm -1 for the chain chitosan-based flocculant was an amide I absorption peak, at 1547cm -1 was an amide II absorption peak, at 2934cm -1 was an antisymmetric stretching vibration peak of the C-H bond of-CH 2 on the cyclohexyl group, and at 2855cm -1 was a symmetrical stretching vibration peak of the C-H bond on the cyclohexyl group, thus demonstrating that the chitosan-based flocculant was successfully prepared.
FIG. 7 is an X-ray photoelectron spectrum of a chitosan-based flocculant;
As can be seen from fig. 7: C1S, O1S and N1S orbitals exist in chitosan and chain chitosan-based flocculants, and C1S, O1S, N1S and S2p orbitals exist in comb-shaped chitosan-based flocculants.
Application effect test:
The comb-type chitosan-based flocculant prepared in example 1 and the chain-type chitosan-based flocculant prepared in example 2 were tested for application in dye decolorization, as follows:
Five dyes (congo red CR, acid chrome blue ACrB, alizarin green AG, acid orange AO and yellow soap MY) were tested for their decolorization rate in the range of 0-100mg/l of flocculant (comb-like chitosan-based flocculant prepared in example 1 and chain-like chitosan-based flocculant prepared in example 2), with a concentration of 50mg/l of simulated dye wastewater. At room temperature, the flocculant is added into the simulated dye wastewater, the flocculant is firstly stirred rapidly for two minutes at 400rpm, then stirred slowly for 15 minutes at 100rpm, and finally the flocculant is left to stand for precipitation for 1 hour. The supernatant was filtered through a 0.45 μm filter and the residual dye concentration in the filtrate was determined by uv spectrophotometry. The highest decolorization rate of the comb-shaped chitosan-based flocculant pair CR, ACrB, AG, AO and MY is 98.97%,97.20%,94.71%,91.24% and 83.17% in sequence, and the optimal addition amounts are 14mg/l, 65mg/l, 40mg/l, 70mg/l and 30mg/l in sequence. The highest decolorization rate of the chain chitosan-based flocculant to CR, ACrB, AG, AO and MY is 9.40%,97.80%,97.66%,92.17% and 85.76% in sequence, and the optimal addition amounts of the chain chitosan-based flocculant to CR, ACrB, AG, AO and MY are 8mg/l, 40mg/l, 30mg/l, 40mg/l and 20mg/l in sequence. The chitosan-based flocculant synthesized by the invention realizes the efficient removal of dye.
Based on the optimal dosage of chitosan-based flocculant, the decolorization condition of initial pH range of 2-12 and initial Congo red concentration of 50mg/l was tested. At room temperature, flocculants (comb-type chitosan-based flocculant prepared in example 1 and chain-type chitosan-based flocculant prepared in example 2) were added to the simulated dye wastewater, rapidly stirred at 400rpm for two minutes, then slowly stirred at 100rpm for 15 minutes, and finally allowed to stand for precipitation for 1 hour. The supernatant was filtered through a 0.45 μm filter and the residual dye concentration in the filtrate was determined by uv spectrophotometry.
FIG. 13 is a graph comparing the decolorizing effect of chitosan-based flocculant on Congo red at different pH values;
from fig. 13, it can be seen that the decoloring effect of the chitosan-based flocculant is less affected by acidic conditions, and the dye wastewater with the pH in the range of 2-9 can be effectively decolored.
Based on the optimal addition amount of the chitosan-based flocculant, the decolorization condition that the initial turbidity is in the range of 7-160NTU and the initial Congo red concentration is 50mg/l is tested. At room temperature, flocculants (comb-type chitosan-based flocculant prepared in example 1 and chain-type chitosan-based flocculant prepared in example 2) were added to the simulated dye wastewater, rapidly stirred at 400rpm for two minutes, then slowly stirred at 100rpm for 15 minutes, and finally allowed to stand for precipitation for 1 hour. The supernatant was filtered through a 0.45 μm filter and the residual dye concentration in the filtrate was determined by uv spectrophotometry.
FIG. 14 is a graph comparing decolorizing effects of chitosan-based flocculants at different turbidity;
as can be seen from fig. 14, the turbidity did not affect the decolorizing effect of the chitosan-based flocculant, which was close to 100%.
Based on the optimum addition amount of the chitosan-based flocculant, the decoloring effect of the flocculant was measured under the condition (K +\Ca2+\Cl-\SO4 2-; concentration: 50 mM) that inorganic ions coexist in the simulated dye wastewater. At room temperature, flocculants (comb-type chitosan-based flocculant prepared in example 1 and chain-type chitosan-based flocculant prepared in example 2) were added to the simulated dye wastewater, rapidly stirred at 400rpm for two minutes, then slowly stirred at 100rpm for 15 minutes, and finally allowed to stand for precipitation for 1 hour. The supernatant was filtered through a 0.45 μm filter and the residual dye concentration in the filtrate was determined by uv spectrophotometry.
FIG. 15 is a graph showing the comparison of decolorizing effect of chitosan-based flocculant under the coexistence of different inorganic ions;
The results in FIG. 15 show that inorganic ions affect CR decolorization primarily by affecting the pH of the solution.
The effect of the initial concentration of dye on the decolorizing effect of the chitosan-based flocculant was investigated. At room temperature, the flocculating agents (the comb-shaped chitosan-based flocculating agent prepared in example 1 and the chain-shaped chitosan-based flocculating agent prepared in example 2) are added into Congo red solution with initial concentration ranging from 25 mg/l to 200mg/l according to the optimal addition amount corresponding to different Congo red initial concentrations, the Congo red solution is rapidly stirred for two minutes at 400rpm, then is slowly stirred for 15 minutes at 100rpm, and finally is settled for 1 hour. The supernatant was filtered through a 0.45 μm filter and the residual dye concentration in the filtrate was determined by uv spectrophotometry.
FIG. 16 is a graph of optimum dosage of chitosan-based flocculant versus initial Congo red concentration versus decolorizing effect of flocculant at different initial Congo red concentrations.
From fig. 16, it was found that the optimum dosage was linearly dependent on the initial congo red concentration, which did not affect the decolorization effect of the flocculant.
Claims (2)
1. The application of the chitosan-based flocculant is characterized in that the chitosan-based flocculant is applied to dye decolorization, wherein the chitosan-based flocculant is a comb-shaped chitosan-based flocculant, and the highest decolorization rate of the comb-shaped chitosan-based flocculant on Congo red, acid chromium blue, alizarin green, acid orange and yellow soap is 98.97%,97.20%,94.71%,91.24% and 83.17% in sequence;
the chitosan-based flocculant is a comb-shaped chitosan-based flocculant;
the structural formula of the comb-shaped chitosan-based flocculant is The preparation method is completed according to the following steps:
1. Preparation of a polydimethyl acrylamide solution:
① . Continuously introducing nitrogen into toluene for 10min to obtain toluene with oxygen removed; dissolving thioglycollic acid into toluene with oxygen removed to obtain thioglycollic acid toluene solution;
The mass fraction of the thioglycollic acid toluene solution in the step one ① is 3%;
② . Adding an initiator into a thioglycollic acid toluene solution with the temperature of 80 ℃, and stirring and dissolving to obtain a reaction system;
The initiator in the first ② is azobisisobutyronitrile;
③ . Dropwise adding N, N-dimethylacrylamide into a reaction system, and stirring and reacting for 4 hours under the condition of nitrogen atmosphere and 80 ℃ to obtain a polydimethyl acrylamide solution;
the molar ratio of N, N-dimethylacrylamide, thioglycollic acid and initiator in step one ③ is 250:25:2;
2. grafting reaction:
① . Dissolving chitosan in 0.5% of dilute hydrochloric acid by mass fraction, and adjusting the pH value to 6 by using 1% of NaOH solution by mass fraction to obtain chitosan solution;
the mass fraction of the chitosan solution in the second ① is 4%;
② . Adding tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride into a polydimethyl acrylamide solution, and uniformly stirring under the nitrogen atmosphere to obtain a reaction solution;
The molar ratio of tetrabutylammonium bromide, hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step two ② to N, N-dimethylacrylamide described in step one ③ is 25:1:1:1;
③ . Adding chitosan solution into the reaction solution, and stirring for 8 hours under nitrogen atmosphere and room temperature to obtain an off-white emulsion solution;
The stirring speed in the second ③ step is 300r/min;
The molar ratio of chitosan to N, N-dimethylacrylamide in the off-white emulsion solution in the step two ③ is 1:10;
④ . Dialyzing the off-white emulsion solution by using deionized water as a dialyzate, precipitating the solution by using acetone, cleaning by using absolute ethyl alcohol, and vacuum drying for 24 hours at 60 ℃ to obtain the comb-shaped chitosan-based flocculant;
The dialysis time described in step two ④ was 12 hours, with dialysate changed every 3 hours.
2. The application of the chitosan-based flocculant is characterized in that the chitosan-based flocculant is applied to dye decolorization, wherein the chitosan-based flocculant is a chain-shaped chitosan-based flocculant, and the highest decolorization rate of the chain-shaped chitosan-based flocculant to acid chrome blue, alizarin green, acid orange and soap yellow is 97.80%,97.66%,92.17% and 85.76% in sequence;
the structural formula of the chain chitosan-based flocculant is The preparation method is completed according to the following steps:
1. dissolving 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride in water to obtain a solution A;
the molar ratio of 4-dimethylaminopyridine to 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride described in step one is 1:3;
2. dissolving chitosan in 0.5 mass percent of dilute hydrochloric acid, and then adjusting the pH value to 8 by using a NaOH solution to obtain a chitosan solution;
The mass fraction of the NaOH solution in the second ① is 1%;
the mass fraction of the chitosan solution in the second ① is 2%;
3. dissolving L-cyclohexylglycine in 0.2% of dilute hydrochloric acid by mass fraction, and regulating the pH value to 2.2 by using NaOH solution to obtain L-cyclohexylglycine solution;
The mass fraction of the L-cyclohexyl glycine solution in the step three is 1.2%;
4. Adding chitosan solution into the solution A, and then dropwise adding L-cyclohexylglycine solution to obtain a reaction system; mechanically stirring the reaction system at room temperature under nitrogen atmosphere to obtain a reaction product;
the molar ratio of chitosan to L-cyclohexylglycine in the reaction system in the fourth step is 3:2;
the molar ratio of the L-cyclohexylglycine to the L-cyclohexylglycine in the reaction system in the fourth step is 4:1;
in the fourth step, the mechanical stirring time is 8 hours, and the mechanical stirring speed is 300r/min;
5. Firstly, dialyzing a reaction product for 6 hours by using dilute hydrochloric acid with the pH value of 2.2, dialyzing the reaction product for 6 hours by using deionized water, precipitating by using acetone, washing by using absolute ethyl alcohol, and drying in vacuum at 60 ℃ for 24 hours to obtain a chain chitosan-based flocculant;
And in the fifth step, the dialysate is replaced every 3 hours.
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| CN105601764A (en) * | 2016-02-22 | 2016-05-25 | 南京师范大学 | Amino-acid-modified chitosan flocculating agent and preparation method and application thereof |
| CN106008987A (en) * | 2016-05-09 | 2016-10-12 | 南京师范大学 | Temperature sensitive chitosan flocculant and preparing method and application thereof |
| CN108359103A (en) * | 2018-02-05 | 2018-08-03 | 南京师范大学 | A kind of hydrophobically modified chitosan flocculant and its preparation method and application |
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|---|---|---|---|---|
| KR20000052018A (en) * | 1999-01-28 | 2000-08-16 | 조정래 | The Manufacturing Method for a High Molecular Coagulant of Chitosan Group |
| CN101302273A (en) * | 2008-06-30 | 2008-11-12 | 重庆大学 | Preparation of chitose-acrylic amide graft copolymerization flocculant |
| CN105601764A (en) * | 2016-02-22 | 2016-05-25 | 南京师范大学 | Amino-acid-modified chitosan flocculating agent and preparation method and application thereof |
| CN106008987A (en) * | 2016-05-09 | 2016-10-12 | 南京师范大学 | Temperature sensitive chitosan flocculant and preparing method and application thereof |
| CN108359103A (en) * | 2018-02-05 | 2018-08-03 | 南京师范大学 | A kind of hydrophobically modified chitosan flocculant and its preparation method and application |
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