CN111704222B - Method for enhancing flocculation capacity of ester flocculant through prehydrolysis - Google Patents
Method for enhancing flocculation capacity of ester flocculant through prehydrolysis Download PDFInfo
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- CN111704222B CN111704222B CN202010729449.7A CN202010729449A CN111704222B CN 111704222 B CN111704222 B CN 111704222B CN 202010729449 A CN202010729449 A CN 202010729449A CN 111704222 B CN111704222 B CN 111704222B
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- 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
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Abstract
The invention discloses a method for strengthening flocculation capacity of an ester flocculant through prehydrolysis, which specifically comprises the following steps: (1) pre-hydrolyzing a flocculating agent: adding a proper amount of ester flocculant AM-g-MPC into distilled water, adding a certain amount of phosphotungstic acid for catalytic hydrolysis, and stirring and hydrolyzing the mixture in a constant-temperature water bath at 40-70 ℃; (2) flocculation: using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with turbidity of about 60 NTU; (3) standing: the treated kaolin wastewater is kept stand for a certain time to realize solid-liquid separation, and then the kaolin suspended particles in the water body can be effectively removed. The method has the advantages that the treatment efficiency of kaolin wastewater reaches more than 92%, the removal rate of the hydrolyzed AM-g-MPC under the same condition is improved compared with that of the AM-g-MPC which is not hydrolyzed, the used materials are easy to prepare, the kaolin wastewater treatment efficiency is high, the treatment cost is low, and the method has good economic benefits and application potentials.
Description
Technical Field
The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for strengthening the flocculation capacity of an ester flocculant through prehydrolysis.
Background
Water resources are important resources for normal operation of a natural ecosystem and survival of human beings, but with the development of world economy, population is continuously increased, cities are gradually increased and expanded, water consumption in various places is continuously increased, meanwhile with the development of industrial production and life, water pollution is increasingly serious, water pollution can cause great harm to ecological environment and biological health, and waste water is often required to be strictly treated to enter a circulating water body for daily use. Improving the quality of water environment, protecting the water environment safety is the focus of government and citizen attention, and the key point for realizing water pollution control lies in the development of water treatment agents and water treatment technologies. The common methods in the water treatment technology comprise methods such as adsorption, flocculation, membrane separation, biological method and the like, wherein the adsorption method is the most applied method in the dye wastewater treatment, the method has the advantages of low investment, simple and convenient operation, short period and the like, and the adsorption method can selectively adsorb certain compounds, so that the method plays an important role in the wastewater treatment; biological methods are more and more concerned because of the advantages of no secondary pollution, low operation cost and the like, but the growth environment requirements of microorganisms and the like required by the biological methods are strict, and the process is unstable; the flocculation method has the advantages of simple process, small occupied area and remarkable effect, and is widely applied. The performance of the flocculating agent is a key factor influencing the treatment effect of the flocculation method, the research on the flocculating agent plays a crucial role in controlling water pollution, and the improvement on the performance of the flocculating agent is a hotspot of research.
The flocculating agent is mainly divided into an inorganic coagulant, an organic flocculating agent and a microbial flocculating agent. Among them, organic flocculants have been receiving much attention in recent years because of their advantages such as high water treatment efficiency, wide application range, various modification forms, and easy degradation. However, in order to further improve the flocculation effect of organic flocculants, in addition to research on new modification methods in preparation, research on methods for enhancing the flocculation effect of flocculants, which can be applied to wastewater treatment processes, is also required. Currently, the research on enhancing the flocculation capacity of the flocculant is less.
Chinese patent application No. CN201710459749.6, entitled "a pig farm wastewater enhanced flocculation method", discloses a method for slowly adding NaOH into a starch solution, stirring and reacting to obtain a modified starch solution; and regulating the pH value of the modified starch solution to 2.0-3.5 by adopting sulfuric acid, then adding the poly-silicon iron into the modified starch solution, maintaining the pH value, reacting in a constant-temperature oscillator at 50-60 ℃ for 3.5-4.5 hours, standing for one night, and curing to prepare the reinforced starch-based composite flocculant. The method has the advantages of novel materials, high non-toxic and harmless degree and the like, but the preparation reaction process is complex, the time consumption is long, slow reaction and continuous stirring are needed, and the energy consumption is high.
Chinese patent application No. CN201910935591.4, entitled harmless treatment method for strengthening flocculation of aquaculture tail water, discloses a method for preliminarily filtering aquaculture tail water, removing large-particle impurities, and then preliminarily flocculating the preliminarily filtered tail water by using an inorganic flocculant; then, carrying out flocculation reinforcement on the tail water after primary flocculation by using a microbial flocculant; then the tail water after flocculation strengthening is treated by using a biological adsorbent, and metal ions remained in the water and generated in the inorganic flocculation process are adsorbed. The method has the advantages of strong pertinence, obvious treatment effect and the like, but the treatment process has long flow, needs two times of flocculation and adsorption, and has the disadvantages of complex operation, large flocculant consumption and low economic benefit.
Therefore, it is necessary to develop a method with simple reaction conditions, high degradation efficiency and low energy consumption to enhance the flocculation capacity of the flocculant.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for enhancing the flocculation capacity of the flocculating agent, which has the advantages of mild reaction conditions, simple and convenient operation, high treatment efficiency and low energy loss.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows, and the method specifically comprises the following steps:
(1) pre-hydrolyzing a flocculating agent: adding 0.2-0.8 g of ester flocculant AM-g-MPC into distilled water, adding a certain amount of phosphotungstic acid for catalytic hydrolysis, wherein the mass ratio of AM-g-MPC to phosphotungstic acid is 2: 1-4: 1, and stirring and hydrolyzing the mixture in a constant-temperature water bath at 40-70 ℃ for 6-12 hours;
(2) flocculation: and (3) using the hydrolyzed AM-g-MPC for flocculation treatment of kaolin wastewater with turbidity of about 60NTU, wherein the addition amount of the flocculant is 10-50 mg/L.
(3) Standing: the treated kaolin wastewater is kept stand for a certain time to realize solid-liquid separation, and then the kaolin suspended particles in the water body can be effectively removed.
Wherein the concentration of the AM-g-MPC in the step (1) is 0.2-0.8%. When the concentration of the AM-g-MPC is lower than 0.2%, the content of the flocculating agent is too low to completely cover the surface layer of the kaolin in the flocculation process, so that the electric neutralization and adsorption bridging effects of the AM-g-MPC are caused, and the flocculation effect is poor; when the concentration of the AM-g-MPC is higher than 0.8%, a large amount of flocculating agents are stacked together, the repulsion force of charges is enhanced, and in addition, the macromolecular chains cannot be stretched, the adsorption capacity is greatly weakened, and the flocculation is not facilitated.
The phosphotungstic acid in the step (1) is a white fine crystal, has acidity and oxidation-reduction property, is a novel multifunctional catalyst, has high catalytic activity and good stability, can be dissolved in water, has no pollution to the environment, and is a green catalyst. The mass ratio of the AM-g-MPC to the phosphotungstic acid is 2: 1-4: 1, when the mass ratio of the AM-g-MPC to the phosphotungstic acid is lower than 2:1, the relative content of the phosphotungstic acid is too high, the pH value of the solution is reduced, a flocculating agent is protonated when amino is in an acidic environment, so that the adsorption capacity is weakened, and the flocculation effect is poor; when the mass ratio of the AM-g-MPC to the phosphotungstic acid is higher than 4:1, the relative content of the phosphotungstic acid is too low, the degree of hydrolysis of the flocculant is not high, and the hydrolysis efficiency is low.
The temperature of the constant-temperature water bath in the step (1) is 40-70 ℃, and the stirring hydrolysis time is 6-12 h. When the temperature of the constant-temperature water bath is lower than 30 ℃, the hydrolysis reaction is very slow, longer hydrolysis time is needed, and the energy consumption is higher; when the temperature of the thermostatic waterbath is higher than 70 ℃, the boiling point of a part of decomposition products is reached, which may result in volatilization of some products and structural damage.
The adding amount of the flocculating agent in the step (2) is 10-50 mg/L. When the addition amount of the flocculating agent is less than 10 mg/L, the concentration of the flocculating agent is small, the electric neutralization of positive charges in the AM-g-MPC cannot completely neutralize negatively-charged suspended particles with high kaolin concentration, and a part of kaolin suspended particles are still in a stable state, so that the flocculating settling speed of the particles is slow; meanwhile, when the adding amount is low, the formed floc is small, the structure is loose and is easy to break, and the treatment effect is poor; when the adding amount of the flocculating agent is more than 50mg/L, the cation units carried by the excessive flocculating agent enable the destabilized colloidal particles to carry positive charges again, the electrical property of the colloidal particles is reversed, the colloidal particles reach a stable state again due to the electrostatic repulsion effect, and the phenomenon of back mixing occurs; meanwhile, the steric effect of the excessive flocculating agent is not beneficial to the coagulation and sedimentation of the colloidal particles.
And (4) standing for 20-30 min in the step (3). The floc settling effect is optimal within 20-30 min; when the standing time is less than 20min, the floc is not completely settled; when the standing time is longer than 30min, the treatment performance cannot be significantly improved, and the increased treatment time may result in an increase in the volume required to treat the structure at the time of actual treatment.
Compared with the prior art, the invention has the following beneficial effects:
1. the monomer 2- (methacryloyloxy) ethyl-2- (trimethylamino) ethyl phosphate (MPC) used by the invention has good biocompatibility, high graft copolymerization efficiency with acrylamide, excellent biodegradation effect and high degree of harmlessness to the environment.
2. The invention hydrolyzes in the process of dissolving the flocculating agent for standby, saves the hydrolysis time, improves the flocculating capability of the flocculating agent through hydrolysis, and has the removal efficiency of kaolin suspension up to more than 92 percent.
3. The prehydrolysis strengthening flocculation method has the advantages of simple process, low energy consumption, low cost and no secondary pollution, so the method has good social and economic benefits for the practical application of various industrial suspension waste liquids.
Detailed Description
The present invention will be described in further detail with reference to specific examples, wherein the raw materials used are common commercial products unless otherwise specified.
Example 1:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: adding 0.2g of ester flocculant AM-g-MPC into distilled water to prepare a mixed solution with the concentration of 0.2%, adding phosphotungstic acid for catalytic hydrolysis, wherein the mass ratio of AM-g-MPC to phosphotungstic acid is 2:1, and stirring and hydrolyzing the mixture in a constant-temperature water bath at 40 ℃ for 6 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 20 mg/L.
3) Standing: and standing the treated kaolin wastewater for 20min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
Example 2:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: 0.4g of ester flocculant AM-g-MPC is taken to be added into distilled water to prepare a mixed solution with the concentration of 0.4 percent, phosphotungstic acid is added for catalytic hydrolysis, the mass ratio of AM-g-MPC to phosphotungstic acid is 2:1, and the mixture is stirred and hydrolyzed in a constant temperature water bath at 60 ℃ for 7 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 20 mg/L.
3) Standing: and standing the treated kaolin wastewater for 20min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
Example 3:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: 0.6g of ester flocculant AM-g-MPC is taken to be added into distilled water to prepare a mixed solution with the concentration of 0.6 percent, phosphotungstic acid is added for catalytic hydrolysis, the mass ratio of AM-g-MPC to phosphotungstic acid is 2:1, and the mixture is stirred and hydrolyzed in a thermostatic water bath at 50 ℃ for 8 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 30 mg/L.
3) Standing: and standing the treated kaolin wastewater for 30min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
Example 4:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: adding 0.2g of ester flocculant AM-g-MPC into distilled water to prepare a mixed solution with the concentration of 0.2%, adding phosphotungstic acid for catalytic hydrolysis, wherein the mass ratio of AM-g-MPC to phosphotungstic acid is 3:1, and stirring and hydrolyzing the mixture in a constant-temperature water bath at 40 ℃ for 6 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 40 mg/L.
3) Standing: and standing the treated kaolin wastewater for 30min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
Example 5:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: 0.6g of ester flocculant AM-g-MPC is taken to be added into distilled water to prepare a mixed solution with the concentration of 0.6 percent, phosphotungstic acid is added for catalytic hydrolysis, the mass ratio of AM-g-MPC to phosphotungstic acid is 4:1, and the mixture is stirred and hydrolyzed in a constant temperature water bath at 70 ℃ for 9 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 30 mg/L.
3) Standing: and standing the treated kaolin wastewater for 20min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
Example 6:
the flocculation capacity of the ester flocculant is strengthened by prehydrolysis in the following way:
1) pre-hydrolyzing a flocculating agent: 0.8g of ester flocculant AM-g-MPC is taken to be added into distilled water to prepare a mixed solution with the concentration of 0.8 percent, phosphotungstic acid is added for catalytic hydrolysis, the mass ratio of AM-g-MPC to phosphotungstic acid is 2:1, and the mixture is stirred and hydrolyzed in a water bath with constant temperature of 80 ℃ for 7 hours.
2) Flocculation: and (3) using the hydrolyzed AM-g-MPC to flocculate kaolin wastewater with the turbidity of about 60NTU, wherein the adding amount of the flocculating agent is 50 mg/L.
3) Standing: and standing the treated kaolin wastewater for 30min to realize solid-liquid separation, thereby effectively removing kaolin suspended particles in the water body.
The removal efficiency of kaolin suspended particles was measured by the methods described in examples 1-5, and the detailed data are shown in Table 1.
TABLE 1 removal efficiency of Kaolin suspended particles
| Method | Removal efficiency |
| Example 1 | 93.4% |
| Example 2 | 95.2% |
| Example 3 | 93.3% |
| Example 4 | 95.5% |
| Example 5 | 96.2% |
| Example 6 | 94.7% |
As can be seen from the above table 1, the method for enhancing the flocculation capacity of the flocculant through prehydrolysis has an excellent treatment effect on kaolin suspension wastewater, the removal rate is over 92%, the treatment method is simple to operate, the economic benefit is high, an idea is provided for the actual treatment of industrial suspension wastewater, and the method is a high-efficiency and feasible water treatment method capable of being popularized and developed.
The above examples of the present invention are only illustrative of the present invention and are not intended to limit the embodiments of the present invention. Many modifications in different forms will be apparent to those skilled in the art in light of the above teachings. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.
Claims (3)
1. A method for strengthening the flocculation capacity of an ester flocculant through prehydrolysis is characterized by comprising the following steps:
(1) pre-hydrolyzing a flocculating agent: adding 0.2-0.8 g of ester flocculant AM-g-MPC synthesized by graft copolymerization of Acrylamide (AM) and 2- (methacryloyloxy) ethyl-2- (trimethyl amino) ethyl phosphate (MPC) into distilled water, adding a certain amount of phosphotungstic acid for catalytic hydrolysis, wherein the mass ratio of AM-g-MPC to phosphotungstic acid is 2: 1-4: 1, and stirring and hydrolyzing the mixture in a constant-temperature water bath at 40-70 ℃ for 6-12 hours;
(2) flocculation: using the hydrolyzed AM-g-MPC for flocculation treatment of kaolin wastewater with turbidity of 60NTU, wherein the addition amount of a flocculating agent is 10-50 mg/L;
(3) standing: the treated kaolin wastewater is kept stand for a certain time to realize solid-liquid separation, and then the kaolin suspended particles in the water body can be effectively removed.
2. The method for enhancing the flocculation capacity of ester flocculants as claimed in claim 1, wherein the concentration of the AM-g-MPC in step (1) is 0.2-0.8%.
3. The method for enhancing the flocculation capacity of the ester flocculant through prehydrolysis according to claim 1, wherein the standing time in the step (3) is 20-30 min.
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| US6372882B1 (en) * | 2000-04-03 | 2002-04-16 | Nalco Chemical Company | Method for producing substantially dry water-insoluble polymers for improved flocculation in the bayer process |
| EP2115023B1 (en) * | 2007-03-05 | 2012-01-04 | Basf Se | Polyamine-polyacrylate dispersant |
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| CN105084499B (en) * | 2015-08-26 | 2018-07-20 | 中山市高平织染水处理有限公司 | A kind of processing dyeing and printing sewage composite high-molecular sewage treatment flocculating agent and preparation method thereof |
| CN105200236B (en) * | 2015-09-22 | 2017-10-03 | 中国华电科工集团有限公司 | A kind of method and device that W and V is reclaimed from waste flue gas denitration catalyst |
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