CN110372805B - Preparation method of low-residual flocculant in wastewater and wastewater recycling method - Google Patents
Preparation method of low-residual flocculant in wastewater and wastewater recycling method Download PDFInfo
- Publication number
- CN110372805B CN110372805B CN201910700122.4A CN201910700122A CN110372805B CN 110372805 B CN110372805 B CN 110372805B CN 201910700122 A CN201910700122 A CN 201910700122A CN 110372805 B CN110372805 B CN 110372805B
- Authority
- CN
- China
- Prior art keywords
- salt
- flocculant
- wastewater
- temperature
- water
- 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
- C02F1/52—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
- C08B31/00—Preparation of derivatives of starch
- C08B31/08—Ethers
- C08B31/12—Ethers having alkyl or cycloalkyl radicals substituted by heteroatoms, e.g. hydroxyalkyl or carboxyalkyl starch
- C08B31/125—Ethers having alkyl or cycloalkyl radicals substituted by heteroatoms, e.g. hydroxyalkyl or carboxyalkyl starch having a substituent containing at least one nitrogen atom, e.g. cationic starch
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/30—Nature of the water, waste water, sewage or sludge to be treated from the textile industry
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (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
The invention discloses a preparation method of a low-residue flocculant in wastewater and a wastewater recycling method, wherein the preparation method of the flocculant comprises the following steps: step a: synthesizing an environment-responsive flocculant intermediate; step b: synthesizing temperature stimulus response starch; step c: temperature/pH stimuli-responsive starch was synthesized. The method has the beneficial effects that the flocculant prepared by the preparation method can effectively treat industrial printing and dyeing wastewater containing dye, and simultaneously can further remove trace flocculant remained in the salt-containing purified water by changing the temperature and the pH value of the salt-containing purified water after flocculation and color removal to obtain purer high-concentration salt-containing purified water, so that the obtained high-concentration salt-containing purified water can be further recycled in a dyeing process, and the industrial dye wastewater can be recycled.
Description
Technical Field
The invention relates to the technical field of printing and dyeing wastewater treatment, in particular to a preparation method of a low-residue flocculant in wastewater and a wastewater recycling method.
Background
The printing and dyeing wastewater is wastewater discharged by printing and dyeing factories which mainly process cotton, hemp, chemical fibers and blended products thereof. The amount of the printing and dyeing wastewater is large, and 100-200 tons of water are consumed for every 1 ton of textiles which are processed by printing and dyeing, wherein 80-90% of the wastewater becomes wastewater. The textile printing and dyeing wastewater has the characteristics of large water quantity, high organic pollutant content, large alkalinity, large water quality change and the like, and belongs to one of the industrial wastewater difficult to treat. Inorganic salt (sodium chloride or sodium sulfate) and alkaline agent (sodium carbonate) are added in the dyeing process of the reactive dye to inhibit the aggregation of negative charges on the surface of cellulose and promote the adsorption and chemical bonding of the dye on fibers. Therefore, the reactive dye dyeing wastewater contains a large amount of inorganic salt and alkaline agent, wherein the salt content reaches 30-150 g/L. And the discharge of the saline-alkali wastewater can change the water quality of rivers, cause the salinization of soil in peripheral areas and destroy the ecological environment.
Through the analysis of the dyeing process of the cotton fabric reactive dye, the dyed wastewater mainly contains inorganic salt, the undyed reactive dye, sodium carbonate, residual flocculant and the like. If the reactive dyes, sodium carbonate, residual flocculating agent and the like which are not dyed in the wastewater can be removed or reduced, an inorganic salt solution can be obtained, and the solution is an ideal carrier for dyeing cellulose fibers by the reactive dyes. At present, flocculation, membrane filtration, adsorption, photocatalysis and other methods are widely applied to the treatment of printing and dyeing wastewater. Among them, flocculation is a very effective and economical technique for treating dye-containing wastewater. The negative impact of the flocculating adsorbent of inorganic materials on the environment is relatively large and difficult to recycle. After solid-liquid separation is often carried out in the using process, the residual amount of the flocculant with better water solubility in the purified water is very large, so that the clear liquid can not be reused for dyeing. The existing desalination process at home and abroad mainly comprises an ion exchange desalination technology and a membrane separation technology. The ion exchange desalting technology mainly removes harmful ions in water by means of the exchange reaction between ions on an ion exchanger and ions in the wastewater. However, when the salt content of the wastewater is higher than a certain value, the wastewater can quickly reach the exchange saturation capacity of the resin, a large amount of regeneration chemicals are consumed, the consumption of flushing water is increased, the treatment cost is increased, and the operation is complicated. The membrane separation technique is a method of separating some components in a liquid by selectively permeating the components through a special membrane, but has problems such as high membrane cost and low processing speed. The applicant of the invention believes that if the brine obtained after the dye wastewater is decolored can be successfully reused in the dyeing process to realize the recycling of the industrial dye wastewater, the consumption of the sodium sulphate during dyeing is greatly reduced, and the discharge of water and wastewater is reduced. The applicant of the present invention has made relevant studies for this purpose.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation method of a low-residual flocculant in wastewater and a wastewater recycling method, wherein after the flocculant is used for decoloring industrial printing and dyeing wastewater, the residual amount of the flocculant can be reduced by changing the environment (temperature and pH) of the purified water containing salt obtained by decoloring, so that the purified water containing salt with high concentration and with the content of the flocculant reduced or eliminated can be recycled as dyeing water.
In order to solve the technical problem, the invention provides a preparation method of a low-residue flocculant in wastewater, wherein the preparation method comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding cyanuric chloride and water at 0-5 ℃ into a three-neck round-bottom flask provided with a dropping funnel, maintaining the temperature at 0-5 ℃, and the mass ratio of cyanuric chloride to ice water is 1: 4-5; dropwise adding a diethylamine aqueous solution with the mass concentration of 95-99% at the temperature of 20-25 ℃ into a three-neck round-bottom flask at the stirring speed of 300-400r/min, wherein the molar weight of the added cyanuric chloride and diethylamine is 1.5-2: 1; after reacting for 30-45min, heating to 50-55 ℃, dropwise adding 95-99% diethylamine aqueous solution at 50-55 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 1-5 ℃ for 12-24 hours, washing the product with water at the temperature of 0-5 ℃ for several times after the product is solidified, collecting a filter cake, and carrying out vacuum drying at the temperature of 50-60 ℃ for 10-15 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
the reaction of step a can be referred to the following equation:
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
dissolving soluble starch in deionized water, heating to 40-50 ℃, wherein the mass ratio of the soluble starch to the deionized water is 1: 2-2.5; slowly adding NaOH into the system, wherein the molar ratio of the soluble starch to the NaOH is 1-1.2:1, heating to 70-75 ℃, slowly dripping butyl glycidyl ether through a dripping funnel, wherein the molar ratio of the butyl glycidyl ether to the soluble starch is 2-2.5:1, reacting for 4-6 hours, taking out the product, adjusting the pH value of the system to 7.5, precipitating with acetone, dialyzing, and freeze-drying to obtain the temperature-sensitive starch;
the reaction of step b can be referred to the following equation:
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; mixing a mixture of 1: 2-3, dissolving temperature-sensitive starch and NaOH in a dimethyl sulfoxide solution, wherein the mass ratio of the dimethyl sulfoxide solution to the temperature-sensitive starch is 1:20-25, heating to 65-75 ℃ and keeping for 30-40min, adding the flocculant intermediate prepared in the step a under the protection of nitrogen, wherein the molar ratio of the flocculant intermediate to the temperature-sensitive starch is 2-3:1, and heating to 120-130 ℃ for reacting for 8-10 hours; and adjusting the pH value of the product to 7-7.5, precipitating with water, and cleaning with acetone to obtain the low-residue flocculant in clean product wastewater.
The reaction of step c can be referred to the following equation:
in addition, the invention further provides a low-residue flocculant in wastewater directly prepared by the preparation method. Namely, the preparation method comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding cyanuric chloride and water at 0-5 ℃ into a three-neck round-bottom flask provided with a dropping funnel, maintaining the temperature at 0-5 ℃, and the mass ratio of cyanuric chloride to ice water is 1: 4-5; dropwise adding a diethylamine aqueous solution with the mass concentration of 95-99% at the temperature of 20-25 ℃ into a three-neck round-bottom flask at the stirring speed of 300-400r/min, wherein the molar weight of the added cyanuric chloride and diethylamine is 1.5-2: 1; after reacting for 30-45min, heating to 50-55 ℃, dropwise adding 95-99% diethylamine aqueous solution at 50-55 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 1-5 ℃ for 12-24 hours, washing the product with water at the temperature of 0-5 ℃ for several times after the product is solidified, collecting a filter cake, and carrying out vacuum drying at the temperature of 50-60 ℃ for 10-15 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
the reaction of step a can be referred to the following equation:
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
dissolving soluble starch in deionized water, heating to 40-50 ℃, wherein the mass ratio of the soluble starch to the deionized water is 1: 2-2.5; slowly adding NaOH into the system, wherein the molar ratio of the soluble starch to the NaOH is 1-1.2:1, heating to 70-75 ℃, slowly dripping butyl glycidyl ether through a dripping funnel, wherein the molar ratio of the butyl glycidyl ether to the soluble starch is 2-2.5:1, reacting for 4-6 hours, taking out the product, adjusting the pH value of the system to 7.5, precipitating with acetone, dialyzing, and freeze-drying to obtain the temperature-sensitive starch;
the reaction of step b can be referred to the following equation:
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; mixing a mixture of 1: 2-3, dissolving temperature-sensitive starch and NaOH in a dimethyl sulfoxide solution, wherein the mass ratio of the dimethyl sulfoxide solution to the temperature-sensitive starch is 1:20-25, heating to 65-75 ℃ and keeping for 30-40min, adding the flocculant intermediate prepared in the step a under the protection of nitrogen, wherein the molar ratio of the flocculant intermediate to the temperature-sensitive starch is 2-3:1, and heating to 120-130 ℃ for reacting for 8-10 hours; and adjusting the pH value of the product to 7-7.5, precipitating with water, and cleaning with acetone to obtain the low-residue flocculant in clean product wastewater.
The reaction of step c can be referred to the following equation:
in addition, the invention further provides an inorganic salt solution for dyeing prepared by using the low-residue flocculant in the wastewater, wherein:
step d: adding the low-residue flocculant in the printing and dyeing wastewater of claim 2 into the printing and dyeing wastewater obtained after dyeing, wherein the mass ratio of the flocculant to the dye in the printing and dyeing wastewater is 1:1-2, adjusting the pH to 1-2, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 7-8, adjusting the temperature of the salt-containing purified water A to 60-70 ℃, precipitating the residual flocculant, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: and (3) determining the salt content of the purified salt-containing water B by using a conductivity meter, and then adjusting the salt concentration of the purified salt-containing water B to 30-150g/L by adding salt or water to obtain purified salt-containing water C.
In addition, the invention further provides a wastewater recycling method using the low-residual flocculant in wastewater, wherein:
step d: adding the low-residue flocculant in the printing and dyeing wastewater of claim 2 into the printing and dyeing wastewater obtained after dyeing, wherein the mass ratio of the flocculant to the dye in the printing and dyeing wastewater is 1:1-2, adjusting the pH to 1-2, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 7-8, adjusting the temperature of the salt-containing purified water A to 60-70 ℃, precipitating low residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: determining the salt content of the salt-containing purified water B by using a conductivity meter, and then adjusting the salt concentration of the salt-containing purified water B to 30-150g/L by adding salt or water to obtain salt-containing purified water C;
step g: dissolving a reactive dye by using the salt-containing purified water C obtained in the step f, and dyeing the cotton fabric; wherein the concentration of the dye liquor is 0.2-1g/L, the bath ratio is 1:15-1:30, and inorganic salt (consistent with industrial dye wastewater, anhydrous sodium sulfate Na is adopted)2SO4) The concentration is 30-150g/L, and the color fixing agent (Na)2CO3) The concentration is 3-30 g/L.
Wherein, the above wastewater recycling method can further comprise the following technical scheme: the step g is further followed by the steps of:
step h: and (d) adding the low-residue flocculant in the printing and dyeing wastewater obtained in the step (g) in the wastewater of claim 2, and performing the step (d-g) again, so that the decolorization of the printing and dyeing wastewater and the cyclic dyeing of the wastewater are realized.
The method has the beneficial effects that the low-residue flocculant in the wastewater prepared by the preparation method can effectively treat the industrial printing and dyeing wastewater containing the dye, and meanwhile, the salt-containing purified water after flocculation and color removal can be further subjected to temperature and pH value change to remove the residual trace flocculant in the salt-containing purified water, so that purer high-concentration salt-containing purified water is obtained, and therefore, the obtained high-concentration salt-containing purified water can be further recycled in a dyeing process, and the industrial dye wastewater can be recycled.
Drawings
FIG. 1 is a mechanism diagram of capture and release of a model dye molecule by a pH/temperature dual-sensitive intelligent polymer material.
FIG. 2 is a graph of the response of the reversible pH (a) and temperature (b) of TPRS in either example 1 or example 2 of the present invention.
FIG. 3 shows the pH vs. starch derivative TPRS aqueous solutions (DS) at different degrees of substitution in example 1 or 2 of the present inventionBGE＝0.3，DSBEAT0.4, 0.8, 1.2, 1.6).
FIG. 4 is a graph showing the relationship between the Zeta potential and the pH of the TPRS solution in example 1 or 2 of the present invention.
FIG. 5 is a graph showing the effect of flocculation temperature (a) and pH (b) on dye color removal in example 1 or example 2 of the present invention.
FIG. 6 is a graph of the response of the reversible pH (a) and temperature (b) of TPRS in either example 3 or example 4 of the present invention.
FIG. 7 shows the pH vs. starch derivative TPRS aqueous solutions (DS) at different degrees of substitution in example 3 or example 4 of the present inventionBGE＝0.3，DSBEAT0.4, 0.8, 1.2, 1.6).
FIG. 8 is a graph showing the effect of flocculation temperature (a) and pH (b) on dye color removal in example 3 or example 4 of the present invention.
FIG. 9 is a flow chart of a simulated printing process of example 5 of the present invention.
FIG. 10 is a standard curve of the concentration C of the simulated dye wastewater and the absorbance A in example 5 of the present invention.
FIG. 11 is a standard curve of flocculant solution concentration C versus absorbance A for either example 1 or example 2.
FIG. 12 is a graph of the residual amount of flocculant for brackish clean water A in example 6 or example 7 at different pH's (both temperatures 60 ℃ C.).
FIG. 13 shows sodium sulfate Na in example 72SO4Standard curve of salt solution concentration versus conductivity.
FIG. 14 is a block diagram of a process flow system for removing color from printing and dyeing wastewater and recycling saline water in example 9 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail with reference to specific examples.
Example 1: the embodiment of the invention discloses a preparation method of a low-residue flocculant in wastewater, which comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding 0.08mol of cyanuric chloride and 75mL of 5 ℃ water into a 250mL three-neck round-bottom flask provided with a dropping funnel, and maintaining the temperature at 5 ℃; 0.16mol of diethylamine aqueous solution with the mass concentration of 99 percent at 20 ℃ is dripped into a three-mouth round-bottom flask under the stirring speed of 350 r/min; after reacting for 30min, heating to 50 ℃, dropwise adding 99% diethylamine aqueous solution at 50 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 5 ℃ for 12 hours, washing the product for several times by using water at the temperature of 5 ℃ after the product is solidified, collecting a filter cake, and drying the filter cake in vacuum at the temperature of 60 ℃ for 10 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
0.062mol soluble starch is dissolved in 20.5ml deionized water and heated to 45 ℃; then slowly adding 0.062mol of NaOH into the system, heating to 75 ℃, slowly dripping 0.124mol of butyl glycidyl ether into the system through a dropping funnel, reacting for 5 hours, taking out a product regulating system, adjusting the pH value to 7.5, separating out with acetone, dialyzing, and freeze-drying to obtain temperature-sensitive starch;
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; dissolving 0.05mol of temperature-sensitive starch and 0.15mol of NaOH in 120g of dimethyl sulfoxide solution, heating to 70 ℃ and keeping for 30min, adding 0.15mol of flocculant intermediate prepared in the step a under the protection of nitrogen, and heating to 120 ℃ for reaction for 10 hours; and adjusting the pH value of the product to 7.5, separating out the product by using water, and washing the product by using acetone to obtain the low-residue flocculant in the clean product wastewater.
Example 2: the embodiment of the invention also discloses a low-residue flocculant in wastewater, and the preparation method comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding 0.08mol of cyanuric chloride and 75mL of 5 ℃ water into a 250mL three-neck round-bottom flask provided with a dropping funnel, and maintaining the temperature at 5 ℃; 0.16mol of diethylamine aqueous solution with the mass concentration of 99 percent at 20 ℃ is dripped into a three-mouth round-bottom flask under the stirring speed of 350 r/min; after reacting for 30min, heating to 50 ℃, dropwise adding 99% diethylamine aqueous solution at 50 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 5 ℃ for 12 hours, washing the product for several times by using water at the temperature of 5 ℃ after the product is solidified, collecting a filter cake, and drying the filter cake in vacuum at the temperature of 60 ℃ for 10 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
0.062mol soluble starch is dissolved in 20.5mL deionized water and heated to 45 ℃; slowly adding 0.062mol of NaOH into the system, heating to 75 ℃, slowly dripping 0.124mol of butyl glycidyl ether into the system through a dropping funnel, reacting for 5 hours, taking out a product regulating system, adjusting the pH value to 7.5, separating out acetone, dialyzing and freeze-drying to obtain temperature-sensitive starch;
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; dissolving 0.05mol of temperature-sensitive starch and 0.15mol of NaOH in 120g of dimethyl sulfoxide solution, heating to 70 ℃ and keeping for 30min, adding 0.15mol of flocculant intermediate prepared in the step a under the protection of nitrogen, and heating to 120 ℃ for reaction for 10 hours; and adjusting the pH value of the product to 7.5, precipitating with water, and cleaning with acetone to obtain the low-residue flocculant in the clean product wastewater.
The performance of the waste water prepared by the method of example 1 and example 2 with low residual flocculant (i.e. temperature/pH stimuli responsive starch, hereinafter referred to as TPRS) is shown in fig. 1-5.
Wherein, FIG. 1 is a diagram of the mechanism of trapping and releasing model dye molecules by TPRS. (a) Is structural formula of high molecular material of TPRS, and (b) is capture and release mechanism process of TPRS to model dye molecule. When the temperature T is more than LCST and the pH is more than pH, the TPRS releases dye molecules, and the dye molecules with good water solubility are re-dispersed into the aqueous solution; the TPRS captures dye molecules when the temperature T < LCST, pH < pH, and anionic dye molecules combine with tertiary amine groups on the protonated TPRS to form floc precipitates.
Wherein, fig. 2 is a graph of reversible ph (a) and temperature (b) responses of TPRS, measurement conditions: the temperature is 25 ℃, the wavelength is 590nm, and the pH range is 1-8. FIG. 2(a) is a graph of the effect of pH on solution transmittance (transmittance can illustrate the solubility of a flocculant in water, with greater transmittance illustrating greater solubility,smaller indicates lower solubility), the solution is clear and transparent at a pH of 1 or less, and the light transmittance does not change much because the amine group is protonated under acidic conditions, and when the pH is higher<The light transmittance of the solution at 1 exceeds 90 percent, which shows that almost all amine groups on the starch chain are protonated and converted into the cationic form, and the solution system reaches the protonation balance. Due to electrostatic repulsion between the cationic charges of the polymer, the polymer forms a more relaxed molecular conformation, macroscopically manifested by the dissolution of the polymer into water to form a homogeneous solution. At pH values above 1, the BEAT groups on the starch chain gradually deprotonate back to the self-assembled form of ammonia, the hydrophobic interaction of the alkyl and triazine rings predominating, leading to the agglomeration of the polymer chains which precipitate from the aqueous phase. This phenomenon is clearly observed during the titration. The transmission of TPRS is reduced from 90% at pH 0.8 to 0.9% at pH 1.5. As can be seen, by changing the order of acid and base addition, the phase change caused by pH is stable and reversible. FIG. 2(b) shows 2 temperature increases and decreases versus aqueous TPRS (DS)BGE＝0.3，DSBEAT0.4, pH 0.5) uv-visible transmittance. Along with the temperature rise, the solution gradually becomes turbid, and the solution can recover a clear state after the temperature is reduced, which indicates that the phase change of the temperature-sensitive material is completely reversible. The preparation of temperature-sensitive starch derivatives can be carried out by grafting an appropriate number of hydrophobic groups onto the starch chain, the introduction of which disrupts the intermolecular and intramolecular hydrogen bonding of the starch, thereby affecting the lower critical temperature (LCST) of the polymer solution. Thus, changing environmental factors (pH, temperature, etc.) can reduce the residual amount of flocculant in water.
Wherein, FIG. 3 shows pH versus starch derivative TPRS aqueous solution (DS) at different degrees of substitutionBGE＝0.3， DSBEAT0.4, 0.8, 1.2, 1.6). As shown in the figure, degree of substitution DSBEATThe number of hydroxyl groups on the TPRS molecule of 1.6 is relatively small, the degree of bed substitution is high, and thus the light transmittance of the solution increases only at a very low pH. Degree of substitution DSBEATThe TPRS having a molecular chain of 1.2 has a small number of hydroxyl groups (high degree of BEAT substitution), whereas the degree of substitution DS is highBEAT＝0.4, the molecular chain of the TPRS has a large number of hydroxyl groups (the BEAT substitution degree is low), and the protonation degree of the tertiary amine groups on the TPRS is greatly improved under low pH, so that the hydrophilicity of polymer chain segments is increased, and the light transmittance of the solution is improved.
Wherein, FIG. 4 is a graph showing the relationship between Zeta potential and pH of TPRS solution, and 0.5 wt% concentration sample aqueous solution (DS) is preparedBGE＝0.3，DSBEAT0.4), the tendency of the Zeta potential of an aqueous starch solution to change with pH was determined using a Zetasizer Nano-ZS 90. As can be seen from the figure, the pH is increased from 2.5 to 5.9, and the Zeta potential of the solution is reduced from 18.9mV to-5.4 mV; the pH increased from 2.0 to 6.1 and the Zeta potential of the solution decreased from 15.8 mV to-4.0 mV. The Zeta potential of the colloidal particles reflects the charge density on the surface of the colloidal particles, and the TPRS contains tertiary amine groups, so that the amine groups are protonated and have positive charges under acidic conditions. When the pH is higher<At 3.0, the Zeta potential did not change much, indicating that the tertiary amine group on the TPRS reached protonation equilibrium at this pH. With the increase of pH, the protonation degree of the tertiary amine gradually decreases, the amount of free amine increases, the surface charge amount of colloidal particles decreases, and therefore the Zeta potential of the solution decreases.
Wherein, FIG. 5(a) is a graph showing the influence of flocculation temperature on the removal rate of dye chromaticity, and as shown in FIG. 5(a), the flocculation temperature (20-90 ℃) on TPRS (DS) was investigatedBGE0.3 and DSBEAT0.6) influence of the flocculation effect. Concentration of experimentally fixed dye C00.2g/L, flocculant dosage Cf0.14g/L and a dye solution pH of 1.0. As shown, the flocculation process is temperature sensitive, with the dye removal rate decreasing from 96.1% to 61.2% as the solution temperature increases from 20 ℃ to 80 ℃. This is because the degree of substitution is DSBGE＝0.3,DSBEATThe LCST of the TPRS, 0.6, is close to 46 ℃. Below the LCST the flocculant is water soluble as water can form hydrogen bonds with the hydroxyl moieties on the starch and BGE. As the temperature increases, the hydroxyl moieties become partially dehydrated and hydrophobic interactions dominate, causing the flocculant to precipitate. FIG. 5(b) is a graph showing the effect of pH on the removal of dye chromaticity. Flocculation tests were performed at an initial dye concentration of 0.2g/L, with a fixed flocculant dose of 0.225g/L (DS)BGE0.3 and DSBEAT0.6) and 0.275g/L (DS)BGE0.3 and DSBEAT0.4), the pH was adjusted from 0.5 to 3, and the effect of flocculation pH on dye color removal was investigated. As shown in the figure, the pH value of the solution has great influence on the flocculation effect, when the initial pH value of the solution is lower than 1, the color removal rate of the dye is kept at about 90%, and as the pH value of the flocculation solution is increased, R% is gradually reduced. The pH-responsive polymers generally contain ionizable groups (weak acids or bases) that accept or donate protons as the pH of the environment changes. At lower pH, the ionization degree of the tertiary amine group on TPRS increases significantly, and the ionized cationic group electrostatically interacts to attract the anionic dye, thus increasing the dye color removal rate.
In conclusion of the measured solution property data, the TPRS has temperature and pH sensitive characteristics, and the LCST of the TPRS can be adjusted by adjusting the pH and the temperature of the solution, which proves that the residual amount of the flocculating agent in the wastewater can be greatly reduced by utilizing the LCST. And the flocculating agent has better flocculation effect and can be used for removing color of dye wastewater.
Example 3: the embodiment of the invention discloses a preparation method of a low-residue flocculant in wastewater, which comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding 0.075mol of cyanuric chloride and 80mL of water at 4 ℃ into a 250mL three-neck round-bottom flask provided with a dropping funnel, and maintaining the temperature at 4 ℃; 0.13mol of diethylamine aqueous solution with the mass concentration of 99 percent at 22 ℃ is dripped into a three-mouth round-bottom flask under the stirring speed of 380 r/min; after 35min of reaction, heating to 55 ℃, dropwise adding 99% diethylamine aqueous solution at 55 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 4 ℃ for 20 hours, washing the product for several times by using water at the temperature of 4 ℃ after the product is solidified, collecting a filter cake, and drying the filter cake in vacuum at the temperature of 55 ℃ for 12 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
dissolving 0.062mol soluble starch in 23ml deionized water, and heating to 42 deg.C; slowly adding 0.072mol of NaOH into the system, heating to 72 ℃, slowly dropping 0.104mol of butyl glycidyl ether through a dropping funnel, reacting for 6 hours, taking out a product, regulating the pH value of the system to be 7, precipitating with acetone, dialyzing, and freeze-drying to obtain temperature-sensitive starch;
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; dissolving 0.05mol of temperature-sensitive starch and 0.14mol of NaOH in 150g of dimethyl sulfoxide solution, heating to 75 ℃ and keeping for 35min, adding 0.15mol of flocculant intermediate prepared in the step a under the protection of nitrogen, and heating to 130 ℃ for reaction for 9 hours; and adjusting the pH value of the product to 7, separating out the product by using water, and washing the product by using acetone to obtain the low-residue flocculant in the clean product wastewater.
Example 4: the embodiment of the invention also discloses a low-residue flocculant in wastewater, and the preparation method comprises the following steps:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding 0.075mol of cyanuric chloride and 80mL of water at 4 ℃ into a 250mL three-neck round-bottom flask provided with a dropping funnel, and maintaining the temperature at 4 ℃; 0.13mol of diethylamine aqueous solution with the mass concentration of 99 percent at 22 ℃ is dripped into a three-mouth round-bottom flask under the stirring speed of 380 r/min; after 35min of reaction, heating to 55 ℃, dropwise adding 99% diethylamine aqueous solution at 55 ℃ again, and taking cyanuric chloride reaction as an end point (detecting by thin-layer chromatography [ developing agent: V (ethyl acetate): V (petroleum ether): 1:10 ]); after the reaction is finished, refrigerating the product at the temperature of 4 ℃ for 20 hours, washing the product for several times by using water at the temperature of 4 ℃ after the product is solidified, collecting a filter cake, and drying the filter cake in vacuum at the temperature of 55 ℃ for 12 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
dissolving 0.062mol soluble starch in 23ml deionized water, and heating to 42 deg.C; slowly adding 0.072mol of NaOH into the system, heating to 72 ℃, slowly dropping 0.104mol of butyl glycidyl ether through a dropping funnel, reacting for 6 hours, taking out a product, regulating the pH value of the system to be 7, precipitating with acetone, dialyzing, and freeze-drying to obtain temperature-sensitive starch;
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculating agent intermediate prepared in the step a as a cationic etherifying agent; dissolving 0.05mol of temperature-sensitive starch and 0.14mol of NaOH in 150g of dimethyl sulfoxide solution, heating to 75 ℃ and keeping for 35min, adding 0.15mol of flocculant intermediate prepared in the step a under the protection of nitrogen, and heating to 130 ℃ for reaction for 9 hours; and adjusting the pH value of the product to 7, separating out the product by using water, and washing the product by using acetone to obtain the low-residue flocculant in the clean product wastewater.
The performance of the waste water prepared by the methods of example 3 and example 4 with low residual flocculant (i.e., temperature/pH stimuli-responsive starch, hereinafter referred to as TPRS) is shown in fig. 6-9.
Wherein, fig. 6 is a graph of reversible ph (a) and temperature (b) responses of TPRS, measured conditions: the temperature is 25 ℃, the wavelength is 590nm, and the pH range is 1-8. FIG. 6(a) is a graph of the effect of pH on the transmittance of a solution (transmittance indicates the solubility of a flocculant in water, with greater transmittance indicating greater solubility and lesser solubility), and at pH values below 1, the solution is clear and transparent, with the transmittance remaining substantially at 90% or greater, due to protonation of amine groups under acidic conditions. At pH values above 1, the BEAT groups on the starch chain gradually deprotonate back to the free ammonia form, the hydrophobic interaction of the alkyl and triazine rings predominates, leading to agglomeration of the polymer chains to precipitate from the aqueous phase. This phenomenon is clearly observed during the titration. Transmission of TPRSThe light yield decreased from 95% at pH 0.7 to 40% at pH 1.4. As can be seen, by changing the order of acid and base addition, the phase change caused by pH is stable and reversible. FIG. 6(b) shows 2 temperature increases and decreases versus aqueous TPRS (DS)BGE＝0.5，DSBEAT1.2, pH 0.6). Along with the temperature rise, the solution gradually becomes turbid, and the solution can recover a clear state after the temperature is reduced, which indicates that the phase change of the temperature-sensitive material is completely reversible. The preparation of temperature-sensitive starch derivatives can be carried out by grafting an appropriate number of hydrophobic groups onto the starch chain, the introduction of which disrupts the intermolecular and intramolecular hydrogen bonding of the starch, thereby affecting the lower critical temperature (LCST) of the polymer solution. Thus, changing environmental factors (pH, temperature, etc.) can reduce the residual amount of flocculant in water.
Wherein, FIG. 7 is a graph of the effect of degree of substitution of BEAT groups of TPRS on the phase transition behavior of TPRS, measured conditions: the pH was 0.7, the wavelength was 590nm, and the temperature range was 25-95 ℃. Where TC is defined as the temperature of the polymer solution at which the light transmittance of the solution reaches 50% of the initial value. The results show that: t of TPRSCValue following DSBEATIncreasing and decreasing. When degree of substitution DSBEATWhen increasing from 0.5 to 1.5, TCFrom 75 ℃ to 45 ℃. Generally, the increase of the hydrophobic unit on the side chain can weaken the hydrogen bond interaction between the temperature-sensitive polymer and water molecules, and the LCST is reduced. Degree of substitution DSBEAT0.3 and DSBEATThe TPRS having 0.4-degree of hydroxyl group in the molecular chain is high (the degree of substitution by BEAT is low), and thus the intermolecular hydrogen bonding is strong, leading to an increase in the LCST. The method further indicates that the LCST of the temperature response polymer can be adjusted in a wide temperature range by adjusting the proportion of the hydrophilic group and the hydrophobic group on the polymer chain, so that the temperature-sensitive material can be applied to different fields.
Wherein, FIG. 8(a) is a graph showing the influence of flocculation temperature on the removal rate of dye chromaticity, and as shown in FIG. 8(a), the flocculation temperature (20-90 ℃) on TPRS (DS) was investigatedBGE0.4 and DSBEAT1.0) the effect of flocculation. Concentration of experimentally fixed dye C00.5g/L, flocculant dosage Cf0.2g/L and dye solutionAt a pH of 0.7. As shown, the flocculation process is temperature sensitive, with the dye removal rate decreasing from 95.1% to 42% as the solution temperature increases from 20 ℃ to 90 ℃. Below the LCST the flocculant is water soluble as water can form hydrogen bonds with the hydroxyl moieties on the starch and BGE. As the temperature rises, the hydroxyl groups are partially dehydrated, and hydrophobic interaction takes a dominant position, so that the flocculating agent is precipitated, and the flocculating effect is reduced. FIG. 8(b) is a graph showing the effect of pH on the removal of dye chromaticity. Flocculation tests were performed at an initial dye concentration of 0.5g/L, with a fixed flocculant dose of 0.3g/L (DS)BGE0.3 and DSBEAT1.0) and 0.275g/L (DS)BGE0.3 and DSBEAT1.2), the pH was adjusted from 0.5 to 3.25, and the effect of flocculation pH on dye color removal was studied. As shown in the figure, the pH value of the solution has great influence on the flocculation effect, when the initial pH value of the solution is lower than 1, the color removal rate of the dye is kept at about 90%, and as the pH value of the flocculation solution is increased, R% is gradually reduced. The pH-responsive polymer typically contains ionizable groups (weak acids or bases) that accept or donate protons as the pH of the environment changes. At lower pH, the ionization degree of the tertiary amine group on TPRS increases significantly, and the ionized cationic group electrostatically interacts to attract the anionic dye, thus increasing the dye color removal rate.
Example 5: and (3) simulating a printing and dyeing process to prepare printing and dyeing wastewater.
The dye liquor was prepared according to the following conventional method: dissolving a certain amount of tap water into the reactive dye, dyeing the cotton fabric to obtain standby printing and dyeing wastewater; wherein the concentration of the dye liquor is 0.2g/L, the bath ratio is 1:20, and inorganic salt (which is consistent with industrial dye wastewater and adopts anhydrous sodium sulphate Na2SO4) 60g/L concentration, and a fixing agent (Na)2CO3) The concentration was 3 g/L. The dyeing process flow is shown in figure 9.
FIG. 10 is a standard curve of the concentration C of the dye used in the method of example 5, represented by R, versus the absorbance A20.99966, the degree of fitting is reasonable, and the relation between the concentration of the dye wastewater and the absorbance is linear, and the method can be used for calculating the flocculating agent in the flocculation processThe flocculating capability and the removal rate of dye molecules are improved.
Example 6: a dyeing inorganic salt solution prepared using a low residual flocculant in the wastewater prepared in example 1 or example 2, comprising the steps of:
step d: taking 5000mL of standby printing and dyeing wastewater obtained after dyeing in the embodiment 5, adding 1000mL of the low-residue flocculant in the wastewater prepared in the embodiment 1 or the embodiment 2, adjusting the addition amount of the flocculant to be 0.5g/L and the pH to be 1, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 8, adjusting the temperature of the salt-containing purified water A to 60 ℃, precipitating low-residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: and measuring the salt content of the saline purified water B to be 54g/L by using a conductivity meter, and adjusting the salt concentration of the saline purified water B to be 60g/L by adding salt to obtain saline purified water C.
Example 7: a wastewater recycling method for removing color by using the low-residue flocculating agent in the wastewater prepared in the embodiment 1 or the embodiment 2 comprises the following steps:
step d: taking 5000mL of standby printing and dyeing wastewater obtained after dyeing in the embodiment 5, adding 1000mL of the low-residue flocculant in the wastewater prepared in the embodiment 1 or the embodiment 2, adjusting the addition amount of the flocculant to be 0.5g/L and the pH to be 1, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 8, adjusting the temperature of the salt-containing purified water A to 60 ℃, precipitating low-residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: determining the salt content of the salt-containing purified water B to be 54g/L by using a conductivity meter, and then adjusting the salt concentration of the salt-containing purified water B to be 60g/L by adding salt to obtain salt-containing purified water C;
step g: using the result of step fDissolving a reactive dye by using saline purified water C, and dyeing the cotton fabric; wherein the concentration of the dye liquor is 0.2g/L, the bath ratio is 1:20, inorganic salt (which is consistent with industrial dye wastewater and adopts anhydrous sodium sulphate Na2SO4) The concentration is 60g/L, and the color fixing agent (Na)2CO3) The concentration was 3 g/L.
Wherein, FIG. 11 is a standard curve diagram of the concentration C and absorbance A of the flocculant solution in example 1, represented by R20.99841, the relationship between flocculant solution concentration C and absorbance A is linear and can be used to determine the residual amount of flocculant in the circulating water.
Wherein, fig. 12 is a graph of the residual amount of flocculant for saline purified water a in example 6 or example 7 at different pH (both temperatures are 60 ℃), as shown in the figure, the residual amount of flocculant decreases from 15% to 2% as the pH increases from 1 to 8. If the flocculating agent is not removed and the dyeing is directly recycled, part of dye is combined with the flocculating agent to be separated out, the dye is lost, and certain dyeing cost is increased. The pH value is 8, the temperature is 60 ℃, the optimal condition is just the optimal condition during printing and dyeing, and the circulating water is proved to be a relatively ideal carrier of the reactive dye.
FIG. 13 is anhydrous sodium sulfate Na in example 72SO4Standard curve diagram of salt solution concentration C and conductivity x, from R20.99961, the fitting degree is reasonable, the relation between the salt solution concentration and the conductivity is linear, and the relationship can be used for calculating the salt content in the salt water recycling process.
Example 8: a wastewater recycling method for removing color by using the low-residue flocculating agent in the wastewater prepared in the embodiment 1 or the embodiment 2 comprises the following steps:
step d: taking 5000mL of standby printing and dyeing wastewater obtained after dyeing in the embodiment 5, adding 1000mL of the low-residue flocculant in the wastewater prepared in the embodiment 1 or the embodiment 2, adjusting the addition amount of the flocculant to be 0.5g/L and the pH to be 1, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 8, adjusting the temperature of the salt-containing purified water A to 60 ℃, precipitating low-residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: determining the salt content of the salt-containing purified water B to be 54g/L by using a conductivity meter, and then adjusting the salt concentration of the salt-containing purified water B to be 60g/L by adding salt to obtain salt-containing purified water C;
step g: dissolving a reactive dye by using the salt-containing purified water C obtained in the step f, and dyeing the cotton fabric; wherein the concentration of the dye liquor is 0.2g/L, the bath ratio is 1:20, inorganic salt (which is consistent with industrial dye wastewater and adopts anhydrous sodium sulphate Na2SO4) The concentration is 60g/L, and the color fixing agent (Na)2CO3) The concentration was 3 g/L.
Step h: and (g) adding the low-residual flocculant in the printing and dyeing wastewater obtained in the step (g) again, and repeating the steps (d-g) again, so that the color of the printing and dyeing wastewater is removed and the wastewater is circularly dyed.
And d-g is repeated for 5 times, the real object colors of the primary dyed fabric and the dyed fabric recycled by the salt water for 5 times are compared, and the real object graph shows that the primary dyed fabric and the dyed fabric recycled by the salt water for 5 times have no obvious color difference and almost the same dyeing effect, so that the salt water can be successfully recycled in the dyeing process by the method disclosed by the invention, and the recycling of the printing and dyeing wastewater is realized.
Example 9: as shown in fig. 14, the embodiment of the invention also discloses a dyeing wastewater color removal and brine recycling system used in the wastewater recycling method, which comprises a dyeing tank, wherein the dyeing tank is respectively connected with a dyeing liquid tank and a brine tank, a flocculation reactor is connected to the rear of the dyeing tank, the rear end of the flocculation reactor is respectively connected with a sludge tank and an adjusting tank through a filter, a double-membrane filter is connected to the rear of the adjusting tank, and a color removal liquid tank and a brine tank are respectively connected to the rear of the double-membrane filter.
FIG. 14 is a process flow diagram of example 9 relating to the entire process for decolorizing printing and dyeing wastewater and recycling the brine. As shown in the figure, after the cotton fabric is dyed in the dyeing tank, the dye wastewater is subjected to flocculation precipitation with a color removal liquid through a flocculation reactor, and then solid-liquid separation is realized after the dye wastewater passes through a filter. The produced floc sludge is discharged into a sludge tank, and the clear liquid is discharged into a regulating tank. And changing the conditions of the temperature, the pH value and the like of the system by the adjusting tank to separate out the flocculant in the residual supernatant, finely separating the flocculant by a double-membrane filter to ensure that the circulating brine reaches the qualified standard of recycling, discharging the circulating brine into the brine tank for circular dyeing, and discharging the filtered flocculant into the decolorizing tank for circular use.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention, without departing from the technical solution of the present invention, still belong to the protection scope of the technical solution of the present invention.
Claims (5)
1. The preparation method of the low-residue flocculant in wastewater is characterized by comprising the following steps of:
step a: synthesizing a high-molecular modified starch environmental-responsive flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine, and specifically comprising the following steps:
adding cyanuric chloride and water with the temperature of 0-5 ℃ into a three-neck round-bottom flask provided with a dropping funnel, wherein the mass ratio of the cyanuric chloride to ice water is 1: 4-5; dropwise adding a diethylamine aqueous solution with the mass concentration of 95-99% at the temperature of 20-25 ℃ into a three-neck round-bottom flask at the stirring speed of 300-400r/min, wherein the molar weight of the added cyanuric chloride and diethylamine is 1.5-2: 1; after reacting for 30-45min, heating to 50-55 ℃, dropwise adding a diethylamine aqueous solution with the mass concentration of 95-99% at 50-55 ℃ again, and taking the cyanuric chloride reaction as the end point; after the reaction is finished, refrigerating the product at the temperature of 1-5 ℃ for 12-24 hours, washing the product with water at the temperature of 0-5 ℃ for several times after the product is solidified, collecting a filter cake, and carrying out vacuum drying at the temperature of 50-60 ℃ for 10-15 hours to obtain a white solid flocculant intermediate 2, 4-bis (diethylamino) -6-chloro- [1, 3, 5] -triazine;
step b: synthesizing temperature stimulus response starch, which comprises the following steps:
dissolving soluble starch in deionized water, heating to 40-50 ℃, wherein the mass ratio of the soluble starch to the deionized water is 1: 2-2.5; then slowly adding NaOH into the system, wherein the molar ratio of the soluble starch to the NaOH is 1-1.2:1, heating to 70-75 ℃, slowly dripping butyl glycidyl ether through a dropping funnel, wherein the molar ratio of the butyl glycidyl ether to the soluble starch is 2-2.5:1, reacting for 4-6 hours, taking out a product, regulating the pH value of the system to be 7-7.5, precipitating with acetone, dialyzing, and freeze-drying to obtain the temperature-sensitive starch;
step c: synthesizing temperature/pH stimulus responsive starch, and comprises the following steps:
b, taking the temperature-sensitive starch prepared in the step b as a raw material, and taking the flocculant intermediate prepared in the step a as a cationic etherifying agent; mixing a mixture of 1: 2-3, dissolving temperature-sensitive starch and NaOH in a dimethyl sulfoxide solution, wherein the mass ratio of the dimethyl sulfoxide solution to the temperature-sensitive starch is 1:20-25, heating to 65-75 ℃ and keeping for 30-40min, adding the flocculant intermediate prepared in the step a under the protection of nitrogen, wherein the molar ratio of the flocculant intermediate to the temperature-sensitive starch is 2-3:1, and then heating to 120-130 ℃ for reacting for 8-10 hours; and adjusting the pH value of the product to 7-7.5, precipitating with water, and cleaning with acetone to obtain the low-residue flocculant in clean product wastewater.
2. A low residual flocculant in wastewater directly prepared by the preparation method of claim 1.
3. A dyeing inorganic salt solution prepared by using the low residual flocculant in the wastewater of claim 2, characterized by comprising the following steps:
step d: adding the low-residue flocculant in the printing and dyeing wastewater of claim 2 into the printing and dyeing wastewater obtained after dyeing, wherein the mass ratio of the flocculant to the dye in the printing and dyeing wastewater is 1:1-2, adjusting the pH to 1-2, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 7-8, adjusting the temperature of the salt-containing purified water A to 60-70 ℃, precipitating low-residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: and (3) determining the salt content of the purified salt-containing water B by using a conductivity meter, and then adjusting the salt concentration of the purified salt-containing water B to 30-150g/L by adding salt or water to obtain purified salt-containing water C.
4. A method for recycling wastewater using the low residual flocculant in wastewater according to claim 2, comprising the steps of:
step d: adding the low-residue flocculant in the printing and dyeing wastewater of claim 2 into the printing and dyeing wastewater obtained after dyeing, wherein the mass ratio of the flocculant to the dye in the printing and dyeing wastewater is 1:1-2, adjusting the pH to 1-2, performing flocculation precipitation, and performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water A;
step e: d, adjusting the pH value of the salt-containing purified water A obtained in the step d to 7-8, adjusting the temperature of the salt-containing purified water A to 60-70 ℃, precipitating low-residual flocculant in the residual wastewater, and further performing suction filtration by using a plate-and-frame suction filter to obtain salt-containing purified water B;
step f: determining the salt content of the salt-containing purified water B by using a conductivity meter, and then adjusting the salt concentration of the salt-containing purified water B to 30-150g/L by adding salt or water to obtain salt-containing purified water C;
step g: d, dissolving a reactive dye by using the salt-containing purified water C obtained in the step f, and dyeing the cotton fabric; wherein the concentration of the dye liquor is 0.2-1g/L, the bath ratio is 1:15-1:30, the concentration of the inorganic salt is 30-150g/L, and the concentration of the color fixing agent is 3-30 g/L.
5. The method for recycling waste water according to claim 4, wherein: the step g is further followed by the steps of:
step h: and (d) adding the low-residue flocculant in the printing and dyeing wastewater obtained in the step (g) in the wastewater of claim 2, and performing the step (d-g) again, so that the decolorization of the printing and dyeing wastewater and the cyclic dyeing of the wastewater are realized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910700122.4A CN110372805B (en) | 2019-07-31 | 2019-07-31 | Preparation method of low-residual flocculant in wastewater and wastewater recycling method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910700122.4A CN110372805B (en) | 2019-07-31 | 2019-07-31 | Preparation method of low-residual flocculant in wastewater and wastewater recycling method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110372805A CN110372805A (en) | 2019-10-25 |
| CN110372805B true CN110372805B (en) | 2021-07-06 |
Family
ID=68257214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910700122.4A Active CN110372805B (en) | 2019-07-31 | 2019-07-31 | Preparation method of low-residual flocculant in wastewater and wastewater recycling method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110372805B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112300295A (en) * | 2020-06-12 | 2021-02-02 | 石河子大学 | Preparation method and use method of salt sensitive flocculant |
| CN113583144B (en) * | 2021-08-13 | 2023-07-18 | 石河子大学 | Preparation method and application of one-way memory flocculant |
| CN115028288B (en) * | 2022-06-30 | 2023-06-23 | 四川农业大学 | Self-separation hydrophilic-hydrophobic regulating flocculant and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101619103A (en) * | 2009-07-25 | 2010-01-06 | 大连理工大学 | Temperature-sensitive starch derivative and preparation method thereof |
| CN101830992A (en) * | 2010-04-03 | 2010-09-15 | 大连理工大学 | PH-/temperature dual-sensitive starch derivative and preparation method thereof |
| WO2015137791A1 (en) * | 2014-03-10 | 2015-09-17 | Kaunas University Of Technology | Modified starch flocculant and method of producing thereof |
| CN107162143A (en) * | 2017-07-01 | 2017-09-15 | 辽东学院 | Dyeing waste water purifies flocculant and its dyeing waste water purification applications |
| CN110041440A (en) * | 2019-05-15 | 2019-07-23 | 石河子大学 | A kind of salt density value flocculant and its preparation method and application |
-
2019
- 2019-07-31 CN CN201910700122.4A patent/CN110372805B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101619103A (en) * | 2009-07-25 | 2010-01-06 | 大连理工大学 | Temperature-sensitive starch derivative and preparation method thereof |
| CN101830992A (en) * | 2010-04-03 | 2010-09-15 | 大连理工大学 | PH-/temperature dual-sensitive starch derivative and preparation method thereof |
| WO2015137791A1 (en) * | 2014-03-10 | 2015-09-17 | Kaunas University Of Technology | Modified starch flocculant and method of producing thereof |
| CN107162143A (en) * | 2017-07-01 | 2017-09-15 | 辽东学院 | Dyeing waste water purifies flocculant and its dyeing waste water purification applications |
| CN110041440A (en) * | 2019-05-15 | 2019-07-23 | 石河子大学 | A kind of salt density value flocculant and its preparation method and application |
Non-Patent Citations (4)
| Title |
|---|
| Flocculation of both anionic and cationic dyes in aqueous solutions by the amphoteric grafting flocculant carboxymethyl chitosan-graft-polyacrylamide;Zhen Yang等;《Journal of Hazardous Materials》;20130327;第254-255卷;36-45 * |
| pH响应均三嗪淀粉醚的合成及性能研究;史玉琳;《大连理工大学博士学位论文》;20121231;全文 * |
| 微反应器强化染料废水絮凝;张凯强等;《石河子大学学报（自然科学版）》;20170630;第35卷(第3期);293-298 * |
| 淀粉基絮凝剂在染料废水处理中的应用进展;田野等;《染料与染色》;20150228;第52卷(第1期);59-62 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110372805A (en) | 2019-10-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110372805B (en) | Preparation method of low-residual flocculant in wastewater and wastewater recycling method | |
| Lou et al. | Synthesis of a terpolymer based on chitosan and lignin as an effective flocculant for dye removal | |
| Bratskaya et al. | Comparative study of humic acids flocculation with chitosan hydrochloride and chitosan glutamate | |
| Shi et al. | Flocculation behavior of a new recyclable flocculant based on pH responsive tertiary amine starch ether | |
| JPH11500482A (en) | Cellulose particles, production method thereof and use thereof | |
| CN110041440A (en) | A kind of salt density value flocculant and its preparation method and application | |
| DE2365559A1 (en) | METHOD FOR PURIFYING INDUSTRIAL WASTE | |
| CN102311657B (en) | Low-water-solubility fluorescent whitening agent with bactericidal action as well as synthesis method and application thereof | |
| Wang et al. | Fabrication of salt-tolerant chitosan-based polyelectrolyte flocculant through enhancing H-bond hydration effect for treating and recycling of highly saline dyeing wastewater | |
| CN112300295A (en) | Preparation method and use method of salt sensitive flocculant | |
| CN105776481B (en) | Double modified stalk fiber treatment of dyeing/printing wastewaters of xanthate cation and preparation method thereof | |
| KR100423084B1 (en) | Purification of tertiary amine-oxide aqueous solution | |
| CN106905445B (en) | A kind of Polyaminated chitosan decolorising agent of carboxymethyl-and its preparation method and application | |
| EP0042813B1 (en) | Anionic absorbents, process for their preparation and their use in removing cationic agents and heavy-metal ions from aqueous solutions | |
| KR20010042950A (en) | Use of dispersions for paper mill color removal | |
| DE2451698A1 (en) | METHODS FOR CLEANING UP INDUSTRIAL WASTE | |
| JPH07124569A (en) | Decoloration treatment of printing/dyeing waste water | |
| US4391945A (en) | Chelate resin prepared by reacting butane-1,2,3,4-tetra-carboxylic acid or anhydride with polyethylene polyamine | |
| JP2000509009A (en) | Boehmite alumina salt | |
| Bratskaya et al. | Flocculation of humic substances and their derivatives with chitosan | |
| CN113529442A (en) | Method for recycling inorganic salt in dyeing of reactive dye | |
| CN112275328A (en) | Starch-based ion exchange resin with quaternary ammonium group and preparation method and application thereof | |
| KR19980702368A (en) | Cellulose particles, preparation method thereof and uses thereof | |
| CN116375895B (en) | Super-salt sensitive flocculant and preparation method thereof | |
| DE4016543A1 (en) | New modified polyacrylonitrile with amidoxime and hydroxamic acid gps. |
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 | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: 832000 No. four, 221 North Road, the Xinjiang Uygur Autonomous Region, Shihezi Applicant after: Shihezi University Address before: 832000 No. 221 North Fourth Road, Shihezi City, Urumqi City, Xinjiang Uygur Autonomous Region Applicant before: Shihezi University |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |