CN113582283B - Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof - Google Patents
Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof Download PDFInfo
- Publication number
- CN113582283B CN113582283B CN202110889531.0A CN202110889531A CN113582283B CN 113582283 B CN113582283 B CN 113582283B CN 202110889531 A CN202110889531 A CN 202110889531A CN 113582283 B CN113582283 B CN 113582283B
- Authority
- CN
- China
- Prior art keywords
- chitosan
- micro
- water
- amphiphilic
- precipitate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- C02F1/24—Treatment of water, waste water, or sewage by flotation
-
- 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
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/04—Surfactants, used as part of a formulation or alone
-
- 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
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
- Molecular Biology (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- General Health & Medical Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Physical Water Treatments (AREA)
Abstract
The invention belongs to the technical field of sewage treatment, and provides an enhanced air-flotation water purification method by taking amphiphilic chitosan as a micro-nano bubble surface functional modifier, which comprises the following steps: (1) Adding water to amphiphilic chitosan for dissolving to obtain a modifier solution; (2) The modifier solution generates micro-nano bubbles through a bubble generating device and contacts with raw water to be treated to form scum; (3) Separating the scum to obtain treated effluent, and refluxing part of the effluent; the amphiphilic chitosan is a chitosan derivative containing n-butyl or/and n-octyl or hydroxypropyl trimethyl ammonium chloride groups, the substitution degree of the quaternary ammonium salt is 85% -120%, and the substitution degree of the alkyl is 80% -120%. The water purification method has the effects of electric neutralization and adsorption on electronegative pollutants, so that modified micro bubbles are not easy to break; has the characteristics of wide application range, good water outlet quality and the like.
Description
Technical Field
The invention belongs to the technical field of sewage treatment, and relates to an enhanced air-flotation water purification method by using amphiphilic chitosan as a micro-nano bubble surface functional modifier.
Background
At present, the problem of lake and reservoir water source pollution is increasingly prominent, wherein the algae pollution is particularly serious. Eutrophication of lake and reservoir water causes mass propagation of algae, which results in water quality problems such as odor, algae-derived organic matter (AOM), algal toxins, disinfection by-products, and the like. Because the algae cells have small specific gravity,The filter has the characteristics of high negative charge, strong stability and the like, is difficult to sink in water, is difficult to effectively remove by the traditional coagulating sedimentation process, and also causes a series of problems of filter blockage, shortened back washing period, increased dosage and the like. The traditional Dissolved Air Flotation (DAF) process does not damage algae cells in the air flotation process, can effectively avoid the release risk of algal toxins, odor substances and algae source organic matters, and is widely applied to the algae removal process. Before the conventional dissolved air flotation process, coagulation pretreatment is usually carried out, and a coagulant is added into water to enable algal cells in raw water to generate coagulation and flocculation, so that air-entrained flocs can be conveniently formed together with micro bubbles in the subsequent air flotation process. However, OH is easily adsorbed by the gas-liquid interface of microbubbles - The algae cells and the AOM have electronegativity (-7 to-17 mV) at the same time, and the electrostatic repulsion between the microbubbles and the algae cells influences the adhesion effect and the stability; van der Waals force and hydrogen bond action are lacked between the microbubbles and the algae cells, the surfaces of the microbubbles cannot form adsorption bridging and net capturing and sweeping actions on the algae cells, and formed foam aggregates are loose and unstable in adhesion; the bubble diameter generated by the conventional pressurized dissolved air floatation is large (between 30 and 120 mu m), the specific surface area is small, and the dissolved air efficiency of the air floatation is low; and the retention time of the bubbles in water is short, the gas dissolving efficiency is low, and the bubbles cannot be fully combined with pollutants in the water to form compact flocs, so that the trapping effect between the microbubbles and the algae cells is poor, and the adhesion is unstable and easy to desorb.
According to the micro-nano bubble surface function modification air floatation technology, the surface modifier is added into the air dissolving system, so that the surfaces of the generated micro-nano bubbles have positive charges, are bridged and the like, the micro-nano bubbles are not easy to break, and the electrostatic repulsion between the micro-nano bubbles and algae cells is overcome, so that the micro-nano bubbles are easier to contact and adhere with the algae cells, the treatment capacity of air dissolving air floatation is improved, and the quality of outlet water is improved. The cationic surfactant has an amphiphilic structure, cations generated by amino carried by the cationic surfactant can enable micro-nano bubbles to carry positive charges, but the commonly used surfactant such as Cetyl Trimethyl Ammonium Bromide (CTAB) has high toxicity; on one hand, a cationic polymer (such as poly dimethyl diallyl ammonium chloride) can be adhered to the surface of the micro-nano bubbles to enable the micro-nano bubbles to have positive charges, and in addition, a long polymer chain of the polymer can be combined with algae-derived organic matters through the effects of adsorption, bridging and the like to form an organic matter network, so that the contact area of the micro-nano bubbles is increased, but an important precursor dimethylamine of N, N-dimethyl nitramine can be generated during chlorination disinfection, and potential risks are brought to water quality safety and human health.
Chitosan (CTS) is a cationic polysaccharide polymer existing in nature, contains abundant free amino, N-acetamido and hydroxyl in molecules, and has strong adsorption and electric neutralization capacity; meanwhile, the chitosan has a complex spiral linear molecular structure, an interception network can be formed by the long-chain characteristics of the polymer, and the surface contact area of the micro-nano bubbles is increased, so that the adhesion efficiency is enhanced. Meanwhile, chitosan has the characteristics of no toxicity, no harm, easy biodegradation and environmental friendliness, and is approved by the United states environmental protection agency as a purifying agent for drinking water. However, chitosan has the defects of large influence of pH, poor solubility, non-ideal removal effect and the like, the quaternary ammonium salt of chitosan enhances the water solubility, but is adhered to the surface of the micro-nano bubble only by electrostatic force, the hydrogen bond effect is not obvious, the adsorption and bridging effect is not obvious due to the lack of hydrophobic groups, the quaternary ammonium salt of chitosan is easy to desorb under poor hydraulic conditions, great influence is generated on the quality of effluent water, and the application of the quaternary ammonium salt of chitosan is limited. Recent researches show that amino and hydroxyl with strong activity on a chitosan molecular chain are modified, activated and coupled, so that the chitosan molecular chain serving as a micro-nano bubble surface modifier for water purification has a large optimization space and a wide application prospect.
Disclosure of Invention
Aiming at the problems of complex regulation and control mechanism, large dosage, long reaction time, electrostatic repulsion between micro-nano bubbles and algae cells, unstable bubble floc adhesion, large micro-nano bubble size and the like in the coagulation pretreatment stage in the air flotation treatment of the current water plant, the method for removing the algae cells in the water by taking amphiphilic chitosan as the surface functional modifier for the micro-nano bubbles through enhanced air flotation is provided: by adding the micro-nano bubble surface modifier into the water body to be treated, amphiphilic chitosan carrying positive charges is attached to the surface of the micro-nano bubbles, so that electrostatic repulsion between the micro-nano bubbles and algae cells is overcome, and the existing air floatation treatment technology is enhanced.
In order to achieve the purpose, the invention adopts the following technical scheme.
An enhanced air-flotation water purification method by using amphiphilic chitosan as a micro-nano bubble surface functional modifier comprises the following steps:
(1) Adding water to amphiphilic chitosan for dissolving to obtain a modifier solution;
(2) The modifier solution generates micro-nano bubbles through a bubble generating device and contacts with raw water to be treated to form scum;
(3) Separating the scum to obtain treated effluent, and refluxing part of the effluent;
the amphiphilic chitosan is a chitosan derivative containing n-butyl or/and n-octyl or hydroxypropyl trimethyl ammonium chloride groups, the substitution degree of the quaternary ammonium salt is 85% -120%, and the substitution degree of the alkyl is 80% -120%.
Preferably, the concentration of the modifier solution is 0.4mg/L to 1.2mg/L.
Preferably, the pressure inside the bubble generating device is 0.2Mpa to 0.6Mpa.
Preferably, the diameter of the micro-nano bubbles is 0.1-20 μm. The contact time is 10-15min.
Preferably, the reflux ratio of the effluent is 10-25%.
Preferably, the preparation method of the amphiphilic chitosan comprises the following steps:
(1) Mixing a hydroxypropyl trimethyl ammonium chloride chitosan aqueous solution with the quaternary ammonium salt substitution degree of 85% -120% and an ethanol solution of n-butyraldehyde or/and n-octaldehyde, and heating to react at 40-80 ℃ till the reaction is complete to obtain a reaction mixture;
(2) And adding a sodium cyanoborohydride aqueous solution into the reaction mixture to react completely, and separating and purifying the reaction liquid to obtain a product, namely the amphiphilic chitosan.
Preferably, the molar ratio of the hydroxypropyl trimethyl ammonium chloride chitosan to the aldehyde is 1 (0.5-2).
Preferably, the molar ratio of sodium cyanoborohydride to aldehyde in step (2) is 1.
Preferably, the separation and purification steps in the step (2) are as follows: adding acetone into the reaction solution, separating to obtain a precipitate, washing the precipitate with acetone, and drying the precipitate to obtain the catalyst.
A micro-nano bubble enhanced air flotation device used in the water purification method comprises: the dosing device, the bubble generating device and the air floatation tank are sequentially connected through a pipeline;
the dosing device comprises a dosing groove with a flowmeter, a dosing pump and a circulating water tank which are sequentially connected through a pipeline;
the bubble generating device comprises a bubble generator and a bubble releaser; the bubble generator is connected with the circulating water tank through a pipeline; the bubble releaser is arranged in the air floatation tank;
the air floatation tank is divided into a water inlet area, a contact area, a separation area and a water outlet area by a first partition plate, a second partition plate and a third partition plate; the first partition plate is opened at the bottom of the air flotation tank, the second partition plate is opened at the upper part of the air flotation tank, and the third partition plate is opened at the bottom of the air flotation tank; the water inlet area comprises a water inlet pipe and a water pump; a bubble releaser is arranged at the bottom of the contact area; the upper part of the separation area is provided with a slag scraper and a slag floating groove; and the bottom of the water outlet area is provided with a water collector, and the water collector is connected with a reflux pump and a circulating water tank through a pipeline.
Preferably, the water outlet area is further provided with a fourth partition plate, and the fourth partition plate is opened at the upper part of the air floatation tank.
The invention has the following advantages:
the amphiphilic chitosan and the algae-derived organic matter in the raw water both have long-chain structures, the two, microbubbles and algae cells can form a microbubble-amphiphilic chitosan-algae-derived organic matter-algae cell network structure to enhance the pollution removal effect, intermolecular hydrogen bonds formed by the chitosan, the algae cells and the algae-derived organic matter enhance the stability of the network structure, and the amphiphilic chitosan and the algae-derived organic matter have strong cohesive force and capture capacity on pollutants in the water.
The invention utilizes the micro-nano bubble generator to generate micro-nano bubbles with the diameter of 0.1-20 mu m, improves the air dissolving efficiency, has longer retention time and larger internal pressure of the micro-nano bubbles in water and larger specific surface area, can adhere more amphiphilic chitosan under the same condition, improves the utilization rate of the amphiphilic chitosan, and is more compact with floc formed by algae cells.
The invention is a stable circulating overflowing operation mode, omits a coagulation pretreatment stage in the traditional air floatation treatment, simplifies the process treatment flow, has short treatment process, short retention time of the water body to be treated in the system, high treatment efficiency, low technical requirement, low construction and operation cost, can achieve ideal treatment effect by adding a small amount of bubble modifier, and further saves the cost.
The water purification method has the effects of electric neutralization and adsorption on electronegative pollutants, so that modified micro bubbles are not easy to break; has the characteristics of wide application range, good water outlet quality and the like.
Drawings
FIG. 1 is a Fourier transform infrared spectroscopy (FTIR) plot of Chitosan (CTS) and the amphiphilic chitosan obtained in each example;
FIG. 2 is a schematic diagram of a micro-nano bubble enhanced air flotation device;
fig. 3 is a mechanism diagram of a water purification method of amphiphilic chitosan modified micro-nano bubble enhanced air flotation: (a) a traditional air-float adhesion mechanism diagram; (b) A general cationic surfactant reinforced air flotation adhesion mechanism diagram; (c) an enhanced air flotation adhesion mechanism diagram of amphiphilic chitosan; (d) Foam flocs formed by modifying micro-nano bubbles by using amphiphilic chitosan;
FIG. 4 is an infrared spectrum Gaussian fitting peak separation diagram of amphiphilic chitosan modified micro-nano bubble enhanced air flotation floc scum;
fig. 5 is a microscopic photograph of the bubble flocs formed by the micro-nano bubbles: (a) microscopic shooting images of the conventional air flotation bubble flocs; (b) A microscopic shooting picture of the common cationic surfactant reinforced air flotation bubble flocs; (c) Microscopic shooting images of the amphiphilic chitosan reinforced air flotation flocs.
Detailed Description
The present invention will be further described with reference to the following examples and the accompanying drawings, but the present invention is not limited by the following examples.
Example 1 Synthesis of amphiphilic Chitosan
1. Sample No. 1
(1) Weighing 3g of chitosan (the deacetylation degree is 95 percent) and dissolving in 150mL of 2 percent acetic acid solution, then dropwise adding 1mol/L NaOH solution until the pH value is 9, and stirring for 12h at room temperature for alkalization; then carrying out centrifugal separation to obtain a precipitate, and washing the precipitate to be neutral by using water to obtain the alkalized chitosan;
(2) Weighing 3g of 2, 3-epoxypropyltrimethylammonium chloride, adding a small amount of isopropanol, and dissolving to obtain about 20mL of solution;
(3) Adding 100mL of isopropanol into the alkalized chitosan, violently stirring for 1h at 50 ℃ to uniformly disperse the chitosan in the isopropanol, slowly heating to 85 ℃, dropwise adding an isopropanol solution of 2, 3-epoxypropyltrimethylammonium chloride within 1h, continuously heating and stirring for reaction for 8h, cooling the reaction solution to room temperature, adding 150mL of absolute ethyl alcohol, centrifuging to obtain a precipitate, washing the precipitate with the absolute ethyl alcohol, drying at 80 ℃ to constant weight to obtain 2.7g of hydroxypropyl trimethylammonium chloride chitosan with the quaternary ammonium salt substitution degree of about 89%, and grinding to 100 meshes for later use;
(4) Weighing 0.5g of hydroxypropyl trimethyl ammonium chloride chitosan, dissolving in 50mL of distilled water, mixing 0.2mL of 1-octanal, dissolving in 50mL of absolute ethyl alcohol, mixing the two, heating and stirring at 40 ℃, and reacting for 8 hours to obtain a reaction mixture;
(5) Weighing 0.09g of sodium cyanoborohydride, dissolving in water, adding into the reaction mixture obtained in the step (4), stirring for reaction for 12 hours, adding 100mL of acetone into the reaction solution, performing centrifugal separation to obtain a precipitate, washing the precipitate with acetone for 3 times, and drying the precipitate at 50 ℃ in vacuum for 12 hours to obtain the amphiphilic chitosan sample 1, wherein the quaternization substitution degree is 88.64%, and the alkylation substitution degree is 93.58%.
2. Sample 2
(1) Weighing 3g of chitosan (deacetylation degree is 95%) to dissolve in 150mL of 2% acetic acid solution, then dropwise adding 1mol/L NaOH solution until the pH value is 9, and stirring for 10h at room temperature to alkalify; then carrying out centrifugal separation to obtain a precipitate, and washing the precipitate to be neutral by using water to obtain the alkalized chitosan;
(2) Weighing 3g of 2, 3-epoxypropyltrimethylammonium chloride, adding a small amount of isopropanol to dissolve the solution to obtain about 20mL of solution;
(3) Adding 100mL of isopropanol into the alkalized chitosan, violently stirring for 1h at 50 ℃ to uniformly disperse the chitosan in the isopropanol, slowly heating to 75 ℃, dropwise adding an isopropanol solution of 2, 3-epoxypropyltrimethylammonium chloride within 1h, continuously heating and stirring for reaction for 9h, cooling the reaction solution to room temperature, adding 150mL of absolute ethyl alcohol, centrifuging to obtain a precipitate, washing the precipitate with the absolute ethyl alcohol, drying at 80 ℃ to constant weight to obtain 2.7g of hydroxypropyl trimethylammonium chloride chitosan with the quaternary ammonium salt substitution degree of about 93%, and grinding to 100 meshes for later use;
(4) Weighing 0.5g of hydroxypropyl trimethyl ammonium chloride chitosan, dissolving in 50mL of distilled water, mixing 0.2mL of 1-octanal, dissolving in 50mL of absolute ethyl alcohol, mixing the two, and heating and stirring at 80 ℃ for reacting for 6 hours to obtain a reaction mixture;
(5) And (3) weighing 0.09g of sodium cyanoborohydride, dissolving in water, adding into the reaction mixture obtained in the step (4), stirring for reaction for 12 hours, adding 100mL of acetone into the reaction solution, performing centrifugal separation to obtain a precipitate, washing the precipitate with acetone for 3 times, and performing vacuum drying on the precipitate at 50 ℃ for 12 hours to obtain the amphiphilic chitosan sample 2, wherein the quaternization substitution degree is 92.38%, and the alkylation substitution degree is 95.06%.
3. Sample 3
(1) Weighing 3g of chitosan (the deacetylation degree is 99%) and dissolving the chitosan in 150mL of 1% acetic acid solution, then dropwise adding 1mol/L NaOH solution until the pH value is 9, and stirring for 8h at room temperature for alkalization; then carrying out centrifugal separation to obtain a precipitate, and washing the precipitate to be neutral by using water to obtain the alkalized chitosan;
(2) 6g of 2, 3-epoxypropyltrimethylammonium chloride is weighed and dissolved by adding a small amount of isopropanol to obtain about 20mL of solution;
(3) Adding 100mL of isopropanol into the alkalized chitosan, violently stirring for 1h at 50 ℃ to uniformly disperse the chitosan in the isopropanol, slowly heating to 65 ℃, dropwise adding an isopropanol solution of 2, 3-epoxypropyltrimethylammonium chloride within 1h, continuously heating and stirring for reaction for 9h, cooling the reaction solution to room temperature, adding 150mL of absolute ethyl alcohol, centrifuging to obtain a precipitate, washing the precipitate with the absolute ethyl alcohol, drying at 80 ℃ to constant weight to obtain 3.1g of hydroxypropyl trimethylammonium chloride chitosan with the quaternary ammonium salt substitution degree of about 103%, and grinding to 100 meshes for later use;
(4) Weighing 0.5g of hydroxypropyl trimethyl ammonium chloride chitosan, dissolving in 50mL of distilled water, mixing 0.23mL of n-butyl aldehyde, dissolving in 50mL of absolute ethyl alcohol, mixing, heating at 80 ℃, stirring and reacting for 6 hours to obtain a reaction mixture;
(5) And (3) weighing 0.18g of sodium cyanoborohydride, dissolving in water, adding into the reaction mixture obtained in the step (4), stirring for reaction for 10 hours, adding 100mL of acetone into the reaction solution, performing centrifugal separation to obtain a precipitate, washing the precipitate with acetone for 3 times, and performing vacuum drying on the precipitate at 50 ℃ for 12 hours to obtain the amphiphilic chitosan sample 3, wherein the quaternization substitution degree is 103.37%, and the alkylation substitution degree is 118.34%.
4. Sample No. 4
(1) Weighing 3g of chitosan (the deacetylation degree is 99%) and dissolving the chitosan in 150mL of 2% acetic acid solution, then dropwise adding 1mol/L NaOH solution until the pH value is 9, and stirring for 10h at room temperature for alkalization; then, carrying out centrifugal separation to obtain a precipitate, and washing the precipitate to be neutral by using water to obtain the alkalized chitosan;
(2) Weighing 9g of 2, 3-epoxypropyltrimethylammonium chloride, adding a small amount of isopropanol to dissolve the chloride to obtain about 20mL of solution;
(3) Adding 100mL of isopropanol into the alkalized chitosan, violently stirring for 1h at 50 ℃ to uniformly disperse the chitosan in the isopropanol, slowly heating to 75 ℃, dropwise adding an isopropanol solution of 2, 3-epoxypropyltrimethylammonium chloride within 1h, continuously heating and stirring for reaction for 8h, cooling the reaction solution to room temperature, adding 150mL of absolute ethyl alcohol, centrifuging to obtain a precipitate, washing the precipitate with the absolute ethyl alcohol, drying at 80 ℃ to constant weight to obtain 3.3g of hydroxypropyl trimethylammonium chloride chitosan with the quaternary ammonium salt substitution degree of about 105%, and grinding to 100 meshes for later use;
(4) Weighing 0.5g of hydroxypropyl trimethyl ammonium chloride chitosan, dissolving in 50mL of distilled water, mixing and dissolving 0.45mL of n-butyl aldehyde in 50mL of absolute ethyl alcohol, mixing the two, and heating and stirring at 80 ℃ for reaction for 4 hours to obtain a reaction mixture;
(5) And (3) weighing 0.36g of sodium cyanoborohydride, dissolving in water, adding into the reaction mixture obtained in the step (4), stirring for reaction for 12 hours, adding 100mL of acetone into the reaction solution, performing centrifugal separation to obtain a precipitate, washing the precipitate with acetone for 3 times, and performing vacuum drying on the precipitate at 50 ℃ for 12 hours to obtain the amphiphilic chitosan sample 4, wherein the quaternization substitution degree is 104.45%, and the alkylation substitution degree is 112.08%.
FTIR patterns of the above sample and Chitosan (CTS) are shown in FIG. 1, 3481cm -1 Is the stretching vibration peak of CTS hydroxyl (-OH) at 1600cm -1 In the form of a CTS free amino group (-NH) 2 ) Characteristic absorption peak of 2928 cm -1 And 2857 cm -1 Is of methyl (-CH) on CTS 3 ) And methylene (-CH) 2 -) of the vibration peak of stretching. After the CTS is modified by quaternization, the absorption peak of free amino is weakened, a characteristic absorption peak representing imine (-NH-) appears at 1669cm-1, and the absorption peak at 1480cm -1 In which the radical represents-CH in a quaternary ammonium group 3 The characteristic absorption peak of the chitosan indicates that 2, 3-epoxypropyltrimethylammonium chloride and chitosan have-NH 2 The reaction produced hydroxypropyltrimethylammonium chloride chitosan (HTCC). The HTCC is 2928 cm after being subjected to alkylation modification -1 And 2857 cm -1 Has an increased peak intensity of 1669cm -1 The absorption peak at-NH-is further enhanced compared to HTCC, indicating that aldehydes of different carbon chain lengths are associated with-NH of CTS 2 The reaction takes place, and amphiphilic chitosan is formed.
Embodiment 2 micro-nano bubble strengthening air flotation device
The micro-nano bubble enhanced air flotation device shown in fig. 2 comprises: the dosing device, the bubble generating device and the air floatation tank are sequentially connected through a pipeline;
the dosing device comprises a dosing groove 1 with a flowmeter, a dosing pump 2 and a circulating water tank 3 which are connected in sequence through a pipeline;
the bubble generating device comprises a bubble generator 4 and a bubble releaser 5; the bubble generator 4 is connected with the circulating water tank 3 through a pipeline; the bubble releaser 5 is arranged in the air floatation tank;
the air floatation tank is divided into a water inlet area 7, a contact area 8, a separation area 9 and a water outlet area 10 by a first clapboard 6-1, a second clapboard 6-2 and a third clapboard 6-3; the first partition plate 6-1 is opened at the bottom of the floatation tank, the second partition plate 6-2 is opened at the upper part of the floatation tank, and the third partition plate 6-3 is opened at the bottom of the floatation tank; the water inlet area 7 comprises a water inlet pipe 7-1 and a water pump 7-2; the bottom of the contact area 8 is provided with a bubble releaser 5; the upper part of the separation area 9 is provided with a slag scraper 9-1 and a scum groove 9-2; the water outlet area 10 is also provided with a fourth partition plate 6-4, the fourth partition plate 6-4 is provided with an opening at the upper part of the air floatation tank, the bottom of the water outlet area 10 between the fourth partition plate 6-4 and the wall of the air floatation tank is provided with a water collector 10-1, the water collector 10-1 is a perforated water collector, the water collector 10-1 is connected with a reflux pump 11 and a circulating water tank 3 through a pipeline, and water flows in the direction indicated by an arrow.
Example 3 enhanced air flotation water purification using amphiphilic chitosan as micro-nano bubble surface functional modifier
(1) Adding amphiphilic chitosan into a dosing tank 1 for dissolving, adding the amphiphilic chitosan into a circulating water tank 3 through a dosing pump 2 according to the water amount of the circulating water tank 3 and the dosing amount of 1.0mg/L, then feeding the amphiphilic chitosan into a bubble generator 4, and starting the bubble generator to enable the pressure in the tank to be 0.5Mpa so as to form gas-dissolved water;
(2) Raw water to be treated (algae content 6X 10) 5 Per mL) flows into a water inlet area 7 from a water inlet pipe 7-1 through a water pump 7-2, water in the water inlet area 7 enters a contact area 8 through an opening of a first partition plate 6-1 and contacts micro-nano bubbles with the diameter of 0.1-20 mu m, which are generated by a bubble generator 4 and released by a bubble releaser 5, for 12min to form scum, and the scum flows in along with flowing water through an opening at the upper part of a second partition plate 6-2;
(3) And (3) starting a scum scraper 9-1 in a separation area 9 to collect scum to a scum trough 9-2, allowing treated effluent to flow into an effluent area 10 provided with a water collector 10-1 through an opening at the lower part of a third partition plate 6-3 and an opening at the upper end of a fourth partition plate 6-4, allowing a part of the effluent to flow into the next treatment process, and allowing 15% of the effluent to flow back to the circulating water tank 3 through a return pump 11 through a pipeline.
By adopting the equipment and the working procedures, the hydroxypropyl trimethyl ammonium chloride chitosan (HTCC), the Chitosan (CTS) and the poly dimethyl diallyl ammonium chloride with the dosage of 1.0mg/L are respectively added(PDADMAC) was a control. Respectively measuring the algae cell removal rate and UV of the treated effluent 254 The removal rate and turbidity removal rate were as shown in Table 1:
TABLE 1 treatment effect of different modifiers on algae-containing wastewater
According to the results in table 1, the treatment effect of amphoteric chitosan on algae-containing wastewater is better than that of HTCC, chitosan and common cationic modifier.
The air flotation principle of different modifiers is shown in fig. 3, and fig. 3 (a) is a schematic diagram of the traditional air flotation, wherein in the traditional air flotation, the surfaces of micro bubbles and algae cells are negatively charged, electrostatic repulsion exists between the micro bubbles and the algae cells, and formed bubble flocs are small in volume and loose; as can be seen from fig. 3 (b), the common cationic surfactant can positively charge the surface of the microbubbles, and the algal cells and the microbubbles attract each other and adhere to each other under the action of electrostatic attraction, so that the removal rate of the algal cells is improved; as shown in fig. 3 (c) and (d), after the amphiphilic chitosan is modified, the surfaces of the micro-bubbles are electropositive, the algal cells are captured under the electrostatic attraction and the adsorption and bridging action of the long-chain chitosan molecules, and the formed bubble flocs are compact and not easy to desorb.
As can be seen from FIG. 4, the relative strength of the hydrogen bond between molecules is highest when using octyl-HTCC, because the carbon chain length of octyl-HTCC is longer than that of butyl-HTCC, and the space extending from the surface of the bubble after the adhesion of the microbubbles is larger, so that it is easier to "catch" to more algal cells, and the-OH on octyl-HTCC forms an OH.N bond with the algal cells and the amino acid on AOM, so the relative strength of the hydrogen bond is greater than that of butyl-HTCC. Although the hydrogen bond strength of scum is high when octyl-HTCC is used, the actual decontamination capability is lower than that of butyl-HTCC, so the hydrogen bond interaction between amphiphilic chitosan and algae cells is not the main mechanism influencing the algae removal capability, and the electrostatic attraction and hydrophobic interaction between modified microbubbles and algae cells are probably the main action mechanisms for removing the algae cells.
As can be seen from FIG. 5, the algae removal effect is improved to different degrees after the common cationic surfactant and the amphiphilic chitosan are added. The electrostatic attraction generated by the common cationic surfactant enhances the adhesion between algae cells and bubbles, and the volume of the bubble flocs is larger; the adhesion effect of the microbubbles modified by the amphiphilic chitosan and the algae cells is enhanced most obviously, the volume of the flocs is larger than that of the original flocs, the combination is tighter, and the adsorption-bridging effect, the electrostatic attraction effect and the hydrophobic effect are all main action mechanisms for improving the removal rate.
Claims (3)
1. An enhanced air-flotation water purification method by using amphiphilic chitosan as a micro-nano bubble surface functional modifier is characterized by comprising the following steps:
firstly, adding water into amphiphilic chitosan to dissolve to obtain a modifier solution;
secondly, the modifier solution generates micro-nano bubbles through a bubble generating device and contacts with raw water to be treated to form scum;
thirdly, separating the scum to obtain treated effluent, and refluxing part of the effluent;
the amphiphilic chitosan is a chitosan derivative containing n-butyl or/and n-octyl and hydroxypropyl trimethyl ammonium chloride groups, the substitution degree of the quaternary ammonium salt is 85-120%, and the substitution degree of the alkyl is 80-120%;
the concentration of the modifier solution is 0.4mg/L-1.2mg/L;
the pressure in the bubble generating device is 0.2-0.6 Mpa; the diameter of the micro-nano bubbles is 0.1-20 μm; the contact time is 10-15min;
the preparation method of the amphiphilic chitosan comprises the following steps:
(1) Mixing a hydroxypropyl trimethyl ammonium chloride chitosan aqueous solution with the quaternary ammonium salt substitution degree of 85-120% with an ethanol solution of n-butyl aldehyde or/and n-octyl aldehyde, and heating at 40-80 ℃ for complete reaction to obtain a reaction mixture;
(2) Adding a sodium cyanoborohydride aqueous solution into the reaction mixture to react completely, and separating and purifying the reaction liquid to obtain a product, namely the amphiphilic chitosan;
the molar ratio of the hydroxypropyl trimethyl ammonium chloride chitosan to the aldehyde is 1 (0.5-2); in the step (2), the molar ratio of the sodium cyanoborohydride to the aldehyde is 1.1.
2. The water purification method of claim 1, wherein the reflux ratio of the effluent is 10-25%.
3. The water purification method according to claim 1, wherein the separation and purification step in step (2) is: adding acetone into the reaction solution, separating to obtain a precipitate, washing the precipitate with acetone, and drying the precipitate to obtain the catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110889531.0A CN113582283B (en) | 2021-08-04 | 2021-08-04 | Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110889531.0A CN113582283B (en) | 2021-08-04 | 2021-08-04 | Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113582283A CN113582283A (en) | 2021-11-02 |
| CN113582283B true CN113582283B (en) | 2023-03-31 |
Family
ID=78254872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110889531.0A Active CN113582283B (en) | 2021-08-04 | 2021-08-04 | Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113582283B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114890524B (en) * | 2022-04-18 | 2023-07-25 | 武汉理工大学三亚科教创新园 | Algae removing agent based on amphiphilic dendrimer and algae removing method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110642354A (en) * | 2019-08-20 | 2020-01-03 | 华南农业大学 | Chitosan composite material, preparation method and application thereof in air floatation and collection and recovery of blue-green algae |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102863058B (en) * | 2011-07-08 | 2014-11-26 | 蓝星环境工程有限公司 | Air-floatation water treatment system |
| US20150284673A1 (en) * | 2012-12-13 | 2015-10-08 | Sapphire Energy, Inc. | Harvesting algae from water |
| CN103086456A (en) * | 2013-03-01 | 2013-05-08 | 哈尔滨工业大学 | Method for strengthening separation effect of air floatation process by using micro-bubble modification technology |
| CN103288160B (en) * | 2013-06-14 | 2014-04-23 | 哈尔滨工业大学 | Device for removing algae in eutrophicated water body by mobile floatation platform and application method thereof |
| CN207498173U (en) * | 2017-10-10 | 2018-06-15 | 天津大学 | For the water pump self-suction dissolved air flotation device of seriously polluted river water processing |
| CN108911003A (en) * | 2018-07-27 | 2018-11-30 | 金强 | A kind of micro-nano bubble air-float degreasing device and technique |
| CN110316889A (en) * | 2019-07-11 | 2019-10-11 | 山东建筑大学 | A kind of oxidized form air bearing coupling ultrafiltration water purification system and method |
-
2021
- 2021-08-04 CN CN202110889531.0A patent/CN113582283B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110642354A (en) * | 2019-08-20 | 2020-01-03 | 华南农业大学 | Chitosan composite material, preparation method and application thereof in air floatation and collection and recovery of blue-green algae |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113582283A (en) | 2021-11-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103570948B (en) | A kind of preparation method of porous material of surface grafting beta-cyclodextrin and application | |
| CN102626608A (en) | Straw modified into amphiprotic adsorbent and preparation method thereof | |
| CN113582283B (en) | Micro-nano bubble surface function modifier and air-flotation-enhanced water purification method thereof | |
| JP5780953B2 (en) | Method for preparing a membrane bioreactor mixture | |
| CN103086456A (en) | Method for strengthening separation effect of air floatation process by using micro-bubble modification technology | |
| CN112919602B (en) | Guar gum-inorganic salt hybrid green flocculant applied to intensified dehydration of bottom mud and heavy metal fixation and preparation method thereof | |
| CN104098235B (en) | A kind of casing factory sewage water treatment method | |
| Sun et al. | A novel modified carboxymethyl cellulose hydrogel adsorbent for efficient removal of poisonous metals from wastewater: Performance and mechanism | |
| CN113354049A (en) | Preparation method of hyperbranched magnetic demulsifying flocculant for oil field water treatment | |
| CN113000029A (en) | Preparation method of bio-based adsorption filtration fiber membrane for removing and recovering mercury in oil and gas field sewage | |
| Ahmed et al. | Disarmament of micropollutants from wastewater using nylon waste/chitosan blended with algal biomass as recoverable membrane | |
| Feng et al. | Synthesis of a chitosan-based flocculant CS-gP (AM-IA-AATPAC) and evaluation of its performance on Ni2+ removal: Role of chelating-coordination and flocculation | |
| CN109052715B (en) | Method for removing solid/liquid organic pollutants | |
| CN111203197A (en) | Adsorbing material based on epoxy and amino crosslinking and preparation method thereof | |
| CN101838039A (en) | Method for purifying seawater by taking vanillin modified chitosan as flocculant | |
| CN115321657B (en) | Hydrophobic chitosan-polyaluminium chloride Hmcs-PAC composite flocculant and preparation and application thereof | |
| CN112645423A (en) | Lignin-based polymer flocculant and preparation method thereof | |
| CN102115921A (en) | Glycosylated nanofiber membrane and preparation method and application thereof | |
| CN113621092B (en) | Microbubble surface function modifier and preparation method thereof | |
| WO2011016482A1 (en) | Method for removing substance causative of flow velocity decrease in membrane-separation activated-sludge process | |
| CN114539444A (en) | Modified carboxymethyl chitosan quaternary ammonium salt and preparation method thereof | |
| CN101973653B (en) | Method for treating high-concentration PAM (Polyacrylamide) production wastewater by using composite coagulation method | |
| CN101003006A (en) | Method for preparing SA/APTES hybridization film for separation isomers of phenylalanine | |
| CN108530558B (en) | Preparation method of amphoteric particle flocculant based on sodium alginate | |
| CN202936290U (en) | Miniature integrated device for leachate treatment in compression transfer station |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |