WO2015078241A1

WO2015078241A1 - Method for removing trace amount of toxic pollutants in water by enhanced flocculation of enzyme-loading magnetic particles

Info

Publication number: WO2015078241A1
Application number: PCT/CN2014/088502
Authority: WO
Inventors: 赵赫; 曹宏斌; 张懿; 李玉平; 盛宇星
Original assignee: 中国科学院过程工程研究所
Priority date: 2013-11-29
Filing date: 2014-10-13
Publication date: 2015-06-04
Also published as: CN103708673B; CN103708673A

Abstract

The present invention relates to a method for removing a trace amount of toxic pollutants in water by enhanced flocculation of enzyme-loading magnetic particles. Firstly, the enzyme-loading magnetic particles are added, an enzymatic cross-coupling polymerization reaction is controlled so that a trace amount of toxic pollutants are covalently bonded to an organic macro-molecule structure, and after the reaction, the hydrophobicity and molecular weight of the organic structure are improved; secondly, the enzyme-loading magnetic particles are subjected to magnetic recovery; and finally, a flocculating agent is added, and the pollutants formed by the enzymatic polymerization are easily precipitated and removed through the action of coagulation/flocculation such as electric double layer compression, adsorption electrical neutralization and precipitation net-capturing, so as to ultimately achieve the object of removing a trace amount of the toxic pollutants in water by the enhanced flocculation of enzyme-loading magnetic particles. The present invention has the advantages of a good selectivity and good treatment effect on low-concentration toxic pollutants, enabling enzyme recycling, low cost, etc., and has a wide application range and is suitable for treatment on various natural water, drinking water and wastewater containing low-concentration toxic pollutants.

Description

Method for enhancing flocculation of trace toxic pollutants in water by enzymatic magnetic particles

Technical field

The invention relates to a method for removing organic pollutants in water, in particular to a method for enhancing flocculation and removing trace toxic organic pollutants in water by using magnetic particles loaded with enzymes.

Background technique

With the expansion of human production and living, a large number of exogenous trace toxic pollutants (such as POPs, such as persistent organic pollutants) enter the water environment, and its concentration is low. However, such toxic pollutants are usually highly toxic. Through various ways such as intake and accumulation, trace concentrations can have an abnormal effect on the biological physiological system, and have potential "carcinogenic, teratogenic, mutagenic" effects on the human body. Or the imbalance of the secretion of organisms, and most of them can be accumulated through the bio-chain, and transmitted step by step, thus causing harm to ecosystems and human health.

Traditional conventional water treatment technologies such as biological methods and physical methods are difficult to effectively remove trace organic pollutants. Generally, advanced oxidation techniques and membrane technologies are better for removing toxic pollutants. However, due to the large amount of dissolved organic matter in the water, the treatment efficiency is low and the energy consumption is high. Flocculation is one of the most commonly used advanced treatment processes for water and wastewater. The current enhanced flocculation method mainly involves chemically enhanced flocculation, which mainly changes the structure and morphology distribution of the polymer, such as synthetic polymeric flocculant, organic polymer flocculant or Coagulant, etc. Biochemical enhanced flocculation, such as the use of chemical flocculation and microbial adsorption degradation integrated method to improve water treatment efficiency. Physically enhanced flocculation, such as the use of ultrasound, air floatation and other means to accelerate particle sedimentation. These methods are effective for the removal of suspended colloids, floc particles and some macromolecular organic pollutants, but the removal of trace amounts of toxic pollutants is also limited.

The enzyme catalytic technology has the advantages of high reaction speed, high catalytic activity, high selectivity to low concentration pollutants and mild reaction conditions. Therefore, it has obvious advantages in the treatment of low concentrations of toxic and harmful pollutants. Most Recent studies have found that peroxidase and polyphenol oxidase can catalyze the polymerization of hydrogen peroxide or oxygen, and convert toxic organic pollutants (phenol, aniline, etc.) in water into insoluble dimers or poly-polymers. The body is removed from the wastewater. For example, CN 102329008A proposes a method for removing phenolic pollutants in water by using immobilized laccase based on magnetic mesoporous carbon, but the enzymatic method can only convert pollutants and completely remove micro-pollutants. Enhanced removal process. There are patents that combine enzyme catalysis with other processes to remove contaminants. For example, CN 102701337A proposes a method for synthesizing micro-contaminants in water by enzyme-modified electrode and electro-flocculation in the same system, and selective for low-concentration toxic organic pollutants. Strong, good removal effect, but the electrochemical process is complex, the processing cost is high, and it is not suitable for large-scale water treatment. CN 101817622A proposes an ozone pre-oxidation-laccase deep water treatment method. After the laccase reaction, the effluent is mixed into a sedimentation tank for flocculation and sedimentation, and the flocculation and precipitation portion is only used as a solid-liquid separation means. CN 102863103A proposes a technique for advanced treatment of papermaking pulping wastewater by using ferrite advanced oxidation + flocculation precipitation technology, which is subjected to catalytic oxidation reaction by adding free ferrite (biomimetic enzyme) and hydrogen peroxide, and then flocculation by polyacrylamide. The reaction can better remove high concentrations of lignin and chlorophenol, but its catalytic oxidation and flocculation process is a combination of two systems, covering a large area, and the free biomimetic enzyme can not be recycled and reused. The addition of hydrogen peroxide is costly.

Summary of the invention

The object of the present invention is to overcome the limitations of the existing flocculation process, and propose a method for enhancing the flocculation of trace toxic pollutants in water by using enzymatic magnetic particles.

The principle of the invention is: using enzyme-catalyzed polymerization to strengthen the flocculation process, controlling the enzyme catalytic process by enzyme-catalyzed cross-coupling polymerization, so that a small amount of toxic pollutants are covalently bound into the molecular structure of the macromolecular organic matter, thereby improving flocculation and removing trace toxic pollutants. Processing effect. After the enzyme catalyzed reaction, the hydrophobicity and molecular weight of the organic structure are increased, and it is easier to precipitate and remove by coagulation/flocculation by compressing the electric double layer, adsorbing electric neutralization and sedimentation net, etc., finally achieving the enzymatic magnetic particle enhanced flocculation to remove trace toxic in water. Sewage The purpose of the dye.

The invention provides a method for strengthening flocculation to remove trace toxic pollutants by magnetic immobilized enzyme technology, and the two processes of coupling enzyme catalysis and flocculation in the same system have higher reaction rate and good selectivity for low concentration pollutants, and can be applied not only The enhanced removal of micro-pollutants in natural waters and drinking water can also be applied to enhance the flocculation depth removal of low concentrations of organic matter in wastewater.

To this end, the present invention employs the following technical solutions:

A method for enzymatic magnetic particle reinforced flocculation to remove trace toxic pollutants in water, the method comprising the following steps:

(1) adding enzymatic magnetic particles to raw water, continuing aeration, and performing an enzyme catalyzed reaction;

(2) magnetically recovering the magnetic particles carrying the enzyme after the enzyme catalyzed reaction;

(3) adding a flocculating agent to the water after the enzyme catalytic reaction, the flocculating agent reacts with the enzyme-catalyzed polymerization organic product to produce flocs and precipitates, and the supernatant liquid directly effluent.

The method is simple to retrofit based on a sequencing batch reactor or on the basis of an original coagulation sedimentation tank or a coagulation stirred reactor.

Step (3) After adding the flocculating agent, the flocculation agent reacts with the enzyme-catalyzed polymerization of the organic product to form flocs and precipitates by compressing the electric double layer, the adsorption electric neutralization, and the precipitation net flocculation/flocculation, and the supernatant is directly removed. The effluent finally reaches the purpose of enzymatic polymerization and enhanced flocculation to remove trace toxic organic substances.

The pH of the raw water is adjusted to 4 to 7 before the step (1), and for example, 4.02 to 6.96, 4.3 to 6.6, 4.75 to 6.24, 5 to 6.07, 5.48, etc., preferably 5, may be selected.

Step (1) maintaining a dissolved oxygen concentration of 5 to 40 mg/L, for example, 5.04 to 39.7 mg/L, 5.8 to 30 mg/L, 10 to 24.5 mg/L, 13.4 to 22 mg/L, and 17 to 20 mg/L, 18.6 mg/L or the like, preferably 10 to 30 mg/L.

The temperature of the enzyme catalyzed reaction is 20 to 40 ° C, for example, 20.01 to 39.7 ° C, 24 to 35 ° C, 26.7 to 33.4 ° C, 29 to 32 ° C, 30.8 ° C, etc., more preferably 25 to 40 ° C, and most preferably 30 ° C.

The time of the enzyme catalyzed reaction is 5 to 120 min, for example, 5.03 to 118.6 min, 9 to 104 min, 18.6 to 92 min, 40 to 80 min, 52.3 to 72.8 min, 60 to 67 min, 64 min, etc., further preferably 30 to 90 min. Most preferably 40 to 60 minutes.

The enzyme is stirred during the catalytic reaction; the stirring speed is 20 to 40 r/min, for example, 20.03 to 39.6 r/min, 24 to 36 r/min, 28.7 to 32.3 r/min, 31.5 r/min, and the like can be selected.

The enzymatic magnetic particles are immobilized on a magnetic particle carrier by a covalent coupling method, a crosslinking method, an adsorption method or an embedding method.

The enzyme loading is 5 to 100 U/mg, for example, 5.02 to 99.8 U/mg, 8 to 90 U/mg, 13 to 82.6 U/mg, 25 to 75 U/mg, 40 to 68.4 U/mg, and 48.6 to be selected. 62 U/mg, 54 U/mg, etc., further preferably 20 to 50 U/mg.

The dosage of the magnetic particles loaded with the enzyme is 0.1-2000 mg/L, for example, 0.11 to 1996 mg/L, 0.3 to 1925 mg/L, 1 to 1865 mg/L, 5 to 1750 mg/L, and 16 to 1600 mg/L. 35 to 1486 mg/L, 80 to 1200 mg/L, 134 to 1146 mg/L, 200 to 1080 mg/L, 380 to 900 mg/L, 500 to 746 mg/L, 580 to 700 mg/L, 634 mg/L, etc., further preferably 10 ~100 mg / L, most preferably 50 mg / L.

The enzyme is a phenol oxidase. The phenol oxidase is laccase and/or catecholase.

In the step (1), a reduced type mediator is additionally added to the raw water.

The reduced mediator is one or a combination of at least two of 4-hydroxybenzoic acid, p-hydroxycinnamic acid, syringaldehyde, vanillin, acetosyringone or syringic acid. Typical but non-limiting examples include: 4-hydroxybenzoic acid, syringaldehyde, acetosyringone, syringic acid, a combination of p-hydroxycinnamic acid and syringic acid, a combination of syringaldehyde and acetosyringone, 4-hydroxybenzoic acid and Combination of vanillin, a combination of 4-hydroxybenzoic acid, p-hydroxycinnamic acid and vanillic acid, a combination of acetosyringone, syringaldehyde and syringic acid, p-hydroxyl Combinations of cinnamic acid, syringaldehyde, vanillin, acetosyringone, and syringic acid, and the like, can be used in the practice of the present invention.

The dosage of the reduced type mediator is 0.01 to 10 mmol/L, and for example, 0.011 to 9.9 mmol/L, 0.04 to 9.2 mmol/L, 0.1 to 8 mmol/L, 0.16 to 7.3 mmol/L, and 0.4 to 7 mmol may be selected. /L, 0.86 to 6.3 mmol/L, 1 to 6 mmol/L, 1.7 to 4.6 mmol/L, 2 to 4 mmol/L, 2.2 to 3.6 mmol/L, 2.8 to 3.3 mmol/L, 3 mmol/L, etc., further preferably 2 mmol/L.

The magnetic particle carrier is selected from the group consisting of γ-Fe ₂ O ₃ particles, Fe ₃ O ₄ particles, magnetic core-shell nano materials, magnetic resins, magnetic nanogel particles, magnetic microspheres, magnetic mesoporous carbon or magnetic nano-clay. One or a combination of at least two. Typical but non-limiting examples include: γ-Fe ₂ O ₃ particles, Fe ₃ O ₄ particles, magnetic resins, magnetic microspheres, a combination of magnetic mesoporous carbon and magnetic nanoclay, Fe ₃ O ₄ particles and magnetic core shells Combination of nanomaterials, combination of magnetic core-shell nanomaterials and magnetic resins, combination of magnetic nanogel particles, magnetic microspheres and magnetic nanoclay, γ-Fe ₂ O ₃ particles, magnetic nanogel particles, magnetic resin and magnetic Combinations of mesoporous carbon and the like can be used in the practice of the present invention.

The flocculating agent is selected from one or a combination of at least two of an inorganic flocculant, an organic flocculant or an inorganic-organic composite flocculant.

The inorganic flocculating agent is one or at least two of an aluminum salt, a polymeric aluminum, an iron salt, a polymeric iron, a polymeric aluminum iron, a polymeric aluminum silicon, a polymeric iron silicon, a polymeric aluminum iron silicon, a titanium salt or a polymeric titanium salt. combination. The organic flocculating agent is polyacrylamide, polyacrylic acid, polyquaternary ammonium salt and derivatives thereof.

The dosage of the inorganic flocculant is 2 to 1000 mg/L, for example, 2.03 to 999.6 mg/L, 5 to 980 mg/L, 13 to 975 mg/L, 20 to 900 mg/L, and 53 to 815.6 mg/L. 120 to 800 mg/L, 186.5 to 700 mg/L, 280 to 630.7 mg/L, 400 to 500 mg/L, 465 mg/L, etc., more preferably 10 to 500 mg/L.

The dosage of the organic flocculant is 0.5-100 mg/L, for example, 0.52-96.3 mg/L can be selected. 2 to 92 mg/L, 8 to 80 mg/L, 23 to 71 mg/L, 40 to 62 mg/L, 48 to 53 mg/L, 50.3 mg/L, etc., more preferably 2 to 50 mg/L.

In the step (3) of the present invention, after the flocculating agent is added, rapid stirring and slow stirring are successively performed. First, the rapid agitation is carried out so that the flocculant is thoroughly mixed with the sewage, and the pollutants are quickly destabilized, and then slowly stirred. At this stage, the microfloc further grows into coarse and dense flocs.

The stirring speed of the rapid stirring is 100-300r/min, for example, 100.02-298.6r/min, 118-285r/min, 130-260r/min, 142.3-246.8r/min, 160-230r/min, 182.9 can be selected. ～224r/min, 190 to 217r/min, 196.3 to 210r/min, 207r/min, etc., more preferably 200r/min. The rapid stirring time is 2-8 min, for example, 2.03 to 7.96 min, 2.4 to 7.6 min, 2.55 to 7.32 min, 2.9 to 7 min, 3.5 to 6.2 min, 4 to 6 min, 4.3 to 5.8 min, 5.2 min, etc., further preferred 5min.

The stirring speed of the slow stirring is 20-80r/min, for example, 20.04-78.9r/min, 28-75r/min, 33.4-70.6r/min, 40-64.8r/min, 46.7-62r/min can be selected. 50 to 58.1 r/min, 54 r/min, etc., further preferably 40 r/min. The slow stirring time is 10 to 30 minutes, for example, 10.01 to 29.6 min, 13 to 27.5 min, 14.2 to 26 min, 15.7 to 22 min, 19 to 20 min, etc., and more preferably 20 min.

Taking a sequential batch reactor as an example, a method for enhancing flocculation of a magnetic granule by enzymatic magnetic particles to remove trace toxic pollutants is as follows:

The sequencing batch reactor comprises: an aeration device, a stirring device, a water pump, a reaction zone, a separation zone, a drainage device and the like. The reactor and the water pump are connected by a pipeline, the raw water is pumped from the inlet, and is pumped out from the outlet; the aeration device is externally connected to the air compressor or the air pump, and enters the reaction zone with a certain air flow to provide dissolved oxygen for the enzyme catalysis; The reaction zone is subjected to an enzyme catalysis and flocculation two-stage reaction. In the first stage, the water pump and the aeration device are turned on, and after the reaction zone reaches the predetermined amount of water, the inlet valve is closed, and the enzyme is loaded with the enzyme magnetic After the particles are oxidized, a small amount of toxic pollutants are polymerized. The magnetic particles of the enzyme in the reactor are magnetically recovered and then enter the second stage. At this stage, the aeration is stopped, the flocculant is added, the stirring device is turned on, and the stirring is first performed, so that the flocculating agent and the sewage are thoroughly mixed uniformly, and the pollutants are quickly destabilized. Then, slow stirring is carried out, and at this stage, the microfloc further grows into a coarse, dense floc. The separation zone performs the sedimentation drainage process after the flocculation is completed, and the flocs settle in the separation zone, and when the sedimentation reaches a certain depth, the drainage device starts to work, and the supernatant liquid is discharged to the outside of the reactor through the outlet pipe, during the water level lowering process. Keep the water surface stable and do not disturb the floc layer below to achieve solid-liquid separation.

The invention catalyzes the enzymatic enhanced flocculation in the same system to remove trace toxic pollutants in water. Compared with the existing single enzyme catalysis or flocculation technology, the invention has the following beneficial effects:

(1) Good treatment effect: The method of the invention has strong selectivity for low-concentration toxic organic pollutants, and on the other hand, the enzyme-catalyzed polymerization product can be further removed by flocculation, and the treatment effect is better than that of the enzyme alone; on the other hand, it is toxic to a small amount. The effect of pollutant removal is better than that of flocculation alone. The micro-polluted organic matter undergoes enzyme-catalyzed polymerization, and the molecular weight and structure change, forming a poorly soluble polymer, which is more easily removed by flocculation and precipitation.

(2) High enzyme reaction rate: The immobilization of the biological enzyme on the carrier by chemical bond indicates that the nanoparticle reaction system with the enzyme layer has a spherical surface, the specific surface area is much larger than the planar structure, and more reaction enzyme can be loaded per unit volume. The reaction efficiency is higher and the reaction intensity is greater.

(3) Low reaction cost: the enzyme can be recovered by magnetic field, which prolongs its service life; in addition, it can simultaneously catalyze and flocculate a small amount of toxic pollutants, simplify the treatment process, shorten the process flow, and reduce equipment and facilities. Investment provides the necessary conditions.

(4) Wide range of uses: It is suitable for the treatment of water and wastewater containing various low-concentration organic matter, and can also be used for the repair of water bodies such as lakes, reservoirs, rivers and groundwater that are subject to organic micro-contamination.

The invention is further described in detail below. However, the following examples are merely simple examples of the present invention. The scope of the present invention is not intended to be limited or limited, and the scope of the invention is defined by the appended claims.

detailed description

The technical solution of the present invention will be further described below by way of specific embodiments.

In order to better explain the present invention, it is convenient to understand the technical solution of the present invention, and a typical but non-limiting embodiment of the present invention is as follows:

Example 1

The effective volume of the reactor was 500 mL. The pH of the raw water was adjusted to 4, the reaction temperature was 20 ° C, the reaction time was 120 min, the air flow rate during aeration was 0.1 L/min, the dissolved oxygen concentration was maintained at 5 mg/L, and the stirring speed was 20 r/min. The magnetic carrier particles were selected from magnetic core shell Fe ₃ O ₄ @SiO ₂ immobilized laccase, the enzyme loading was 5 U/mg, and the dosage was 2000 mg/L. The flocculant is made of polymerized aluminum iron silicon and polyacrylic acid. The dosages are 20mg/L and 2mg/L respectively, the rapid stirring time is 2min, the stirring intensity is 100r/min, the slow stirring time is 10min, and the stirring intensity is 20r/min. . The bisphenol A and humic acid solution (concentration: 10 mg/L) were introduced into the enzyme-enhanced flocculation reactor from the water inlet. The water filling time was 30 min, the reaction time was 2 h, and the sedimentation time was 1 h. The system treated effluent bisphenol A removal rate was 90%. Under the same conditions, the bisphenol A removal rate was only 15% using a separate flocculation method. It is indicated that the enzymatic enhanced flocculation can improve the removal rate of bisphenol A.

Example 2

The reactor has an effective volume of 10L. The pH of the raw water was adjusted to 7, the reaction temperature was 40 ° C, the reaction time was 5 min, the air flow rate during aeration was 100 L/min, the dissolved oxygen concentration was maintained at 40 mg/L, and the stirring speed was 40 r/min. The magnetic carrier particles were immobilized with Fe ₂ O ₃ mesoporous carbon, and the enzyme loading was 5 U/mg, and the dosage was 2000 mg/L. The flocculant was selected from polyaluminum chloride, the dosage was 500 mg/L, the rapid stirring time was 8 min, the stirring strength was 300 r/min, the slow stirring time was 20 min, and the stirring strength was 80 r/min. The 4-chlorophenol and humic acid solution (concentration: 10 mg/L) were introduced into the enzyme-enhanced flocculation reactor from the water inlet. The water-filling time was 2 h, the reaction time was 4 h, and the sedimentation time was 2 h. The system treated effluent 4-chlorophenol removal rate was 85%. Under the same conditions, the removal rate of 4-chlorophenol was only 12% using a separate flocculation method. It is indicated that the enzyme-enhanced flocculation can increase the removal rate of 4-chlorophenol.

Example 3

The effective volume of the reactor is 1L. The pH of the raw water was adjusted to 5, the reaction temperature was 30 ° C, the reaction time was 30 min, the air flow rate during aeration was 50 L/min, the dissolved oxygen concentration was maintained at 10 mg/L, and the stirring speed was 25 r/min. The magnetic carrier particles were selected from magnetic microsphere immobilized laccase, the enzyme loading was 100 U/mg, and the dosage was 0.1 mg/L; the reduced mediator was selected from syringaldehyde, and the dosage was 10 mmol/L. The flocculant was selected from polyacrylamide, the dosage was 5 mg/L, the rapid stirring time was 5 min, the stirring strength was 200 r/min, the slow stirring time was 15 min, and the stirring strength was 60 r/min. Naphthalene (10μg/L) and humic acid solution (10mg/L) were introduced into the enzyme-enhanced flocculation reactor from the water inlet. The water filling time was 1h, the reaction time was 3h, and the sedimentation time was 1h. The system treated effluent naphthalene removal rate was 72%. Under the same conditions, the removal rate of naphthalene was only 5% using a separate flocculation method. It is indicated that enzyme-enhanced flocculation can improve the removal rate of naphthalene.

Example 4

The effective volume of the reactor was 500 mL. The pH of the raw water was adjusted to 4.5, the reaction temperature was 25 ° C, the reaction time was 90 min, the air flow rate during aeration was 10 L/min, the dissolved oxygen concentration was maintained at 30 mg/L, and the stirring speed was 33 r/min. The magnetic carrier particles were immobilized by magnetic microsphere immobilized laccase, the enzyme loading was 50 U/mg, and the dosage was 100 mg/L; the reduced mediator was 4-hydroxybenzoic acid, and the dosage was 0.01 mmol/L. The flocculant is selected from aluminum sulfate flocculant, the dosage is 2mg/L, the rapid stirring time is 2min, the stirring intensity is 100r/min, the slow stirring time is 10min, and the stirring intensity is 20r/min. The phenol and humic acid solution (concentration: 10 mg/L) was introduced into the enzyme-enhanced flocculation reactor from the inlet, the water filling time was 30 min, the reaction time was 2 h, and the sedimentation time was 1 h. The system treated effluent phenol removal rate was 88%. Phase Under the same conditions, the phenol removal rate was only 8% using a separate flocculation method. It is indicated that the enzyme-enhanced flocculation can improve the removal rate of phenol.

Example 5

The reactor has an effective volume of 10L. The pH of the raw water was adjusted to 6, the reaction temperature was 40 ° C, the reaction time was 40 min, the air flow rate during aeration was 100 L/min, the dissolved oxygen concentration was maintained at 24 mg/L, and the stirring speed was 30 r/min. The magnetic carrier particles were immobilized with γ-Fe ₂ O ₃ immobilized laccase, the enzyme loading was 100 U/mg, and the dosage was 50 mg/L; the reduced mediator was acetyl syringone, and the dosage was 2 mmol/L. The flocculant was selected from the polymerized iron-polyacrylamide composite flocculant, the dosage was 50 mg/L, the rapid stirring time was 8 min, the stirring strength was 300 r/min, the slow stirring time was 30 min, and the stirring strength was 80 r/min. A mixed solution of humic acid (TOC 10mg/L) and bisphenol A (concentration 10mg/L) was introduced into the enzyme-enhanced flocculation reactor from the water inlet, the water filling time was 2h, the reaction time was 4h, and the sedimentation drainage time was 2h. The effluent bisphenol A removal rate was 95% and the TOC removal rate was 85%. Under the same conditions, the enzyme-catalyzed polymerization did not undergo flocculation reaction, the bisphenol A removal rate was 80%, and the TOC removal rate was 30%. Under the same conditions, using a separate flocculation method, the bisphenol A removal rate was only 20%, and the TOC removal rate was 40%. It is indicated that the enzyme-enhanced flocculation can increase the removal rate of humic acid and bisphenol A.

Example 6

The effective volume of the reactor was 500 mL. The pH of the raw water was adjusted to 6.2, the reaction temperature was 25 ° C, the reaction time was 60 min, the air flow rate during aeration was 0.1 L/min, the dissolved oxygen concentration was maintained at 10 mg/L, and the stirring speed was 28 r/min. The magnetic carrier particles were immobilized with Fe ₃ O ₄ immobilized catecholase, the enzyme loading was 30 U/mg, and the dosage was 10 mg/L. The flocculant is selected from the group consisting of polyaluminum chloride and polyquaternium. The dosages are 40mg/L and 0.5mg/L, the rapid stirring time is 2min, the stirring strength is 100r/min, the slow stirring time is 10min, and the stirring intensity is 20r/min. A mixed solution of triclosan (concentration of 100 μg / L) and fulvic acid (TOC of 10 mg / L) was introduced into the enzyme-enhanced flocculation reactor from the water inlet, the water filling time was 30 min, the reaction time was 2 h, and the sedimentation drainage time was 1 h. . The system treated effluent triclosan removal rate was 90%, and the TOC removal rate was 80%. Under the same conditions, only the enzyme-catalyzed polymerization did not undergo flocculation reaction, the triclosan removal rate was 63%, and the TOC removal rate was 25%. Under the same conditions, the single flocculation method was used, the triclosan removal rate was only 16%, and the TOC removal rate was 35%. It shows that enzyme-enhanced flocculation can improve the removal rate of fulvic acid and triclosan.

Example 7

The reactor has an effective volume of 10L. The pH of the raw water was adjusted to 5.3, the reaction temperature was 30 ° C, the air flow rate of the aeration device was 100 L/min, the dissolved oxygen concentration was maintained at 12 mg/L, and the stirring speed was 25 r/min. The magnetic carrier particles were selected from magnetic clay immobilized laccase, the enzyme loading was 20 U/mg, and the dosage was 2000 mg/L. The flocculant was selected from the group consisting of polymerized aluminum iron and polyacrylic acid. The dosages were 1000mg/L and 100mg/L, the stirring time was 8min, the stirring intensity was 300r/min, the slow stirring time was 20min, and the stirring intensity was 80r/min. A biochemical treatment wastewater (COD concentration: 150 mg/L, phenol 20 mg/L) was introduced into the enzyme-enhanced flocculation reactor from the water inlet. The water-filling time was 2 h, the reaction time was 4 h, and the sedimentation time was 2 h. The system treated effluent phenol removal rate was 71%, and the COD removal rate was 56%. Under the same conditions, only the enzyme-catalyzed polymerization did not undergo flocculation reaction, the phenol removal rate was 48%, and the COD removal rate was 10%. Under the same conditions, the phenol removal rate was 8% and the COD removal rate was 25% using a separate flocculation method. It is indicated that enzymatic catalyzed flocculation can improve the removal rate of phenol and COD in wastewater.

The Applicant declares that the present invention illustrates the processing method of the present invention by the above embodiments, but the present invention is not limited to the above-described operational steps, that is, it does not mean that the present invention must rely on the above-described operational steps to be implemented. It will be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions of the materials selected for the present invention, and the addition of the auxiliary ingredients, the selection of the specific means, etc., are all within the scope of the present invention.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solutions of the present invention within the scope of the technical idea of the present invention. These simple variants All fall within the scope of protection of the present invention.

It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention has various possibilities. The combination method will not be described separately.

In addition, any combination of various embodiments of the invention may be made as long as it does not deviate from the idea of the invention, and it should be regarded as the disclosure of the invention.

Claims

A method for enhancing flocculation of trace toxic pollutants in water by enzymatic magnetic particles, characterized in that the method comprises the following steps:

(1) adding enzymatic magnetic particles to raw water, continuing aeration, and performing an enzyme catalyzed reaction;

(2) magnetically recovering the magnetic particles carrying the enzyme after the enzyme catalyzed reaction;

(3) adding a flocculating agent to the water after the enzyme catalytic reaction, the flocculating agent reacts with the enzyme-catalyzed polymerization organic product to produce flocs and precipitates, and the supernatant liquid is discharged.
The method according to claim 1, wherein the method is carried out by using a sequencing batch reactor or simply modifying the original coagulation sedimentation tank or the coagulation stirred reactor.
The method according to claim 1 or 2, characterized in that the pH of the raw water is adjusted to 4 to 7, preferably 5, before the step (1).
The method according to any one of claims 1 to 3, wherein step (1) maintains a dissolved oxygen concentration of 5 to 40 mg/L, preferably 10 to 30 mg/L;

Preferably, the temperature of the enzyme catalyzed reaction is 20 to 40 ° C, further preferably 25 to 40 ° C, most preferably 30 ° C;

Preferably, the enzyme catalyzes the reaction for 5 to 120 minutes, further preferably 30 to 90 minutes, and most preferably 40 to 60 minutes;

Preferably, the enzyme is stirred during the catalytic reaction; the stirring speed is 20 to 40 r/min.
The method according to any one of claims 1 to 4, wherein the enzyme-loaded magnetic particles in the step (1) are immobilized to the magnetic body by a covalent coupling method, a crosslinking method, an adsorption method or an embedding method. On the particle carrier;

Preferably, the enzyme loading is 5 to 100 U/mg, further preferably 20 to 50 U/mg;

Preferably, the enzyme-loaded magnetic particles are added in an amount of 0.1 to 2000 mg/L, more preferably 10 to 100 mg/L, and most preferably 50 mg/L.
The method according to any one of claims 1, 4, 5, wherein the enzyme is a phenol oxidase;

Preferably, the phenol oxidase is laccase and/or catecholase.
The method according to any one of claims 1 to 6, wherein the step (1) additionally adds a reduced type mediator to the raw water;

Preferably, the reduced mediator is one or a combination of at least two of 4-hydroxybenzoic acid, p-hydroxycinnamic acid, syringaldehyde, vanillin, acetosyringone or syringic acid;

Preferably, the amount of the reduced mediator added is 0.01 to 10 mmol/L, and more preferably 2 mmol/L.
The method according to any one of claims 5 to 7, wherein the magnetic particle carrier is selected from the group consisting of γ-Fe 2 O 3 particles, Fe 3 O 4 particles, magnetic core-shell nano materials, magnetic resins, and magnetic nano-condensation. One or a combination of at least two of colloidal particles, magnetic microspheres, magnetic mesoporous carbon, or magnetic nanoclay.
The method according to any one of claims 1 to 8, wherein the flocculating agent is selected from one or a combination of at least two of an inorganic flocculant, an organic flocculant or an inorganic-organic composite flocculant;

Preferably, the inorganic flocculating agent is one or at least one of an aluminum salt, a polymerized aluminum, an iron salt, a polymeric iron, a polymeric aluminum iron, a polymeric aluminum silicon, a polymeric iron silicon, a polymeric aluminum iron silicon, a titanium salt or a polymeric titanium salt. a combination of the two;

Preferably, the inorganic flocculant is added in an amount of 2 to 1000 mg / L, further preferably 10 to 500 mg / L;

Preferably, the organic flocculant is polyacrylamide, polyacrylic acid, polyquaternium and derivatives thereof;

Preferably, the organic flocculant is added in an amount of 0.5 to 100 mg/L, more preferably 2 to 50 mg/L.
The method according to any one of claims 1-9, characterized in that, after the flocculating agent is added in step (3), rapid stirring and slow stirring are successively performed;

Preferably, the stirring speed of the rapid stirring is 100 to 300 r / min, further preferably 200 r / min;

Preferably, the rapid stirring time is 2 to 8 min, further preferably 5 min;

Preferably, the stirring speed of the slow stirring is 20 to 80 r / min, further preferably 40 r / min;

Preferably, the slow agitation time is from 10 to 30 min, further preferably 20 min.