CN109095591B

CN109095591B - Method for activating persulfate and removing pollutants and application

Info

Publication number: CN109095591B
Application number: CN201811050209.3A
Authority: CN
Inventors: 靳永胜; 李晓薇; 郑燕英; 陆艺飞; 付雪晴; 韩飞; 刘欣玮; 吴峥; 罗健; 郑鑫阳; 程培焱
Original assignee: Beijing Kangpu Tongchuang Biotechnology Co ltd; Beijing University of Agriculture
Current assignee: Beijing Kangpu Tongchuang Biotechnology Co ltd; Beijing University of Agriculture
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2021-07-27
Anticipated expiration: 2038-09-10
Also published as: CN109095591A

Abstract

The invention provides an acetylacetone combined ferrous ion activated persulfate system, a method for removing pollutants by using the same and application thereof²⁺And a persulfate salt, the method for removing the contaminant by the persulfate salt comprises the following steps: adding a ferrous coordination activated persulfate system into wastewater containing organic pollutants and nitrogen-containing pollutants to be treated, and controlling the pH value of a reaction system to be between 2 and 12; degrading at 15-50 deg.C for 5-60 min. The ferrous coordination activated persulfate system forms a composite activated persulfate system which can effectively react with Fe²⁺The protection mechanism is used for achieving the purpose of activating the persulfate, and the useless consumption of the persulfate is not caused.

Description

Method for activating persulfate and removing pollutants and application

Technical Field

The invention relates to the field of pollutant treatment, in particular to an acetylacetone combined ferrous ion activated persulfate advanced oxidation system, a method for deeply degrading pollutants by using the same and application of the system.

Background

With the rapid development of the economy and the deepening of the urbanization degree of China, the amount of industrial wastewater and domestic wastes is increased, and the environmental pollution is more and more serious. In recent years, environmental governance has attracted much attention, and among them, the problem of water pollution is the most urgent. The high COD content and nitrogen element in the water body are a big problem in the current environmental management. Higher COD values in the water body represent more serious organic contamination. The serious overproof nitrogen element can cause eutrophication of water body, leading to mass propagation of algae, reducing the content of dissolved oxygen in water and causing mass death of aquatic animals. In addition, nitrate nitrogen also has potential influence on human body, nitrate can be reduced into nitrite in human body, and reacts with amine substances to generate strong carcinogenic substance N-nitrosamine. Nitrate can also destroy hemoglobin to generate methemoglobin, so that the capability of the hemoglobin for carrying oxygen is lost, and the life safety of human is endangered.

The nitrogen-containing compounds in the sewage mainly come from nitrogen-containing industrial wastewater, urban domestic sewage and leaching loss of nitrogen fertilizers in agricultural irrigation, nitrogen in the water mostly exists in the form of nitrate nitrogen, ammonium nitrogen, a small amount of nitrite nitrogen and organic nitrogen, but the organic nitrogen is relatively poor in water solubility and is easily biodegraded. Therefore, the key point of reducing the nitrogen content of the water body is the degradation of nitrate nitrogen and ammonia nitrogen.

The main methods for degrading nitrogen-containing compounds at present are: the biological denitrification method comprises the steps of converting ammonia nitrogen into nitrate nitrogen by nitrifying bacteria under aerobic conditions, and reducing the nitrate nitrogen and nitrite nitrogen into N by denitrifying bacteria under anaerobic conditions₂. The biological denitrification process is green, has good degradation effect, strict condition requirements, higher treatment cost and low content of high electrolyte or BOD valueThe system effect is poor; the catalytic reduction denitrification method mainly comprises the following steps: a photocatalysis method, which utilizes titanium dioxide as a carrier to remove nitrate nitrogen under ultraviolet illumination; the electrocatalysis method removes nitrate nitrogen in water by an external electric field, although the denitrification effect of the catalytic reduction method is good, the reaction conditions required by the electrocatalysis reduction method cannot be realized in the actual sewage treatment, and the ideal degradation effect is difficult to achieve; the simplest method is a chemical reduction method, and active metals such as Fe, Mg and the like are usually adopted as reducing agents. Iron is favored because of its wide source, low cost, no toxic effect to the environment of the generated trivalent iron after reaction, and easy re-reduction and utilization by reducing agent. However, the system for reducing nitrate nitrogen with iron is greatly affected by pH, and it has been reported that pH is a value at which reduction of nitrate nitrogen with iron is carried out>4, Fe stops reacting with nitrate radical, and ammonium ions are easily generated, so that the removal of nitrate nitrogen can not be realized in a real sense. At present, no ideal method for synchronously removing COD and TN in sewage exists.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The invention aims to provide an advanced oxidation reaction system for deeply degrading pollutants (including organic pollutants in wastewater and nitrogen-containing pollutants) by using acetylacetone and ferrous ion to activate persulfate, wherein the system mainly comprises acetylacetone and Fe²⁺And persulfate to form a complex activated persulfate system. The system can effectively protect and revive Fe in the reaction system²⁺And meanwhile, the acetylacetone can also assist in activating the persulfate, so that the aims of continuously, stably and efficiently activating the persulfate and reducing or avoiding the unnecessary consumption of the persulfate can be fulfilled, and the degradation efficiency and removal effect of COD and TN are improved.

The second objective of the present invention is to provide a method for removing contaminants by using acetylacetone in cooperation with activation of a persulfate system by ferrous ions (using a reductive complexing agent in cooperation with activation of a persulfate by ferrous ions), which is based on the following theoretical principle as shown in formula (1):

（1）

wherein L is other reductive complexing agent, N is Fe²⁺Co-existing hetero metal ions. In the absence of L and N, Fe in the system²⁺Is mainly affected by Fe²⁺AA in an amount of Fe²⁺AA ratio and pH control.

In the method, divalent iron ions free in a solution can be combined by introducing a reducing complexing agent, so that the concentration of the iron ions in the reaction is properly reduced, and the reaction is carried out by using the pH value, the dosage of the complexing agent and the ratio of the complexing agent: fe²⁺The free Fe is regulated and controlled by the proportion of² ⁺The concentration of the sulfate radical is controlled, so that the reaction is carried out towards the direction of attacking pollutants, the efficiency of the medicament is exerted to the maximum extent, and the removal efficiency of the pollutants is improved.

Besides the function of the conventional complexing agent, the complexing agent in the method also has excellent Fe revival per se²⁺And has the ability to directly activate persulfate to form sulfate radicals, thus enabling the achievement of Fe under optimized conditions²⁺And maintaining the long-term activity of Fe²⁺The concentration is constant, thereby ensuring the continuous and stable formation of sulfate radicals and providing conditions for the efficient and deep degradation of organic pollutants and nitrogen-containing pollutants, and the method has good application prospect.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides an advanced oxidation system for activating persulfate by combining acetylacetone and ferrous ions, which mainly comprises acetylacetone and Fe²⁺And persulfate, and the acetylacetone as the reducing complexing agent can form a good composite coordination system with ferrous ions. Acetylacetone: fe²⁺: the molar ratio between the persulfates is controlled between (1 and 5): (1-20): (1-8).

Generally speaking, in the traditional Fe (0) single oxidation denitrification system, Fe (0) is easily oxidized into Fe³⁺And the initial ferrous ion concentration in the solution is too high to be easily foundThe ammonium nitrogen is generated when the total nitrogen in the pollutants is treated, is one of the pollutants of the water body, and is not beneficial to the nontoxic and harmless degradation of the nitrogen-containing compounds. In this case, AA-Fe is used²⁺Advanced oxidation system using Fe²⁺Introducing reducing complexing Agent Acetylacetone (AA) to effectively combine with the divalent iron ions dissociated in the solution, and reducing the effective concentration of the divalent iron ions in the reaction to a certain extent to ensure that Fe²⁺Has proper reducing ability, controls no ammonium ions generated in the denitrification process and directly generates N₂. Meanwhile, the coordination capability of the complexing agent is regulated and controlled by pH, and the free Fe is regulated and controlled by the dosage of the complexing agent²⁺The concentration of the iron oxide is controlled so as to control the generation of sulfate radicals, so that the reaction is carried out towards the attack of nitrogen-containing compounds, and excessive sulfate radicals and Fe are avoided²⁺Annihilation of side reaction and mutual collision quenching, and reduction of persulfate radical and Fe²⁺The side reaction of (2) causes unnecessary consumption of persulfate, thereby maximizing the efficacy of the drug. Fe in solution as the reaction proceeds²⁺The concentration decreases and the coordination equilibrium shifts in the dissociation direction, thus releasing Fe²⁺(ii) a On the contrary, when Fe³⁺Is reduced to produce Fe²⁺The coordination equilibrium is shifted in the direction of the formation of the complex, Fe²⁺The amount is reduced. The result is that the coordination balance realizes the system Fe²⁺A dynamic equilibrium of concentrations. Therefore, under the condition that persulfate exists in the system, continuous and stable excitation can be realized, and the premise is provided for continuous and stable generation of sulfate radicals of the system and continuous oxidative degradation of organic pollutants.

Change of AA addition amount to metal ion Fe²⁺The concentration is effectively adjusted in acetylacetone-Fe²⁺The system has an optimal ratio. Too high complexing dose or too high Fe²⁺The concentration will affect the degradation of the total nitrogen in the system. The inventors therefore made optimal adjustments for AA addition.

Preferably, the ratio of acetylacetone: fe²⁺: the molar ratio between the persulfates is preferably controlled to be (2-4): (4-15): (2-7), optimally controlling the ratio of 3: 10: 4, controlling at an optimal ratioUnder the conditions, the degradation effect can be optimal.

Under the control condition of the molar ratio, the composite material has very good degradation effect on COD (chemical oxygen demand) and total nitrogen pollutants in the sewage, and can be adjusted to a certain extent according to different types of pollutants in the treated sewage, so that the composite material has very wide application prospect in the aspect of treating special wastewater containing refractory substances such as garbage percolate, nanofiltration concentrated solution and the like in the practical application process.

The invention provides a method for deeply degrading pollutants by adopting the persulfate system, which comprises the following steps:

(A) adding acetylacetone combined with ferrous ion activated persulfate into wastewater containing organic pollutants and nitrogen-containing pollutants to be treated, and controlling the pH value of a reaction system to be between 2 and 12;

(B) degrading at 15-50 deg.C for 5-60 min.

In this method, the significance of pH control mainly includes two aspects: 1) influencing the activator Fe²⁺At a high pH, Fe²⁺Will be Fe (OH)₂Form exists and will be oxidized relatively quickly to Fe (OH)₃To be inactivated; 2) influences the ability of the complexing agent to share electrons with metal ions, and has higher concentration of H under the condition of lower pH⁺The metal ion complex is combined with the lone pair electrons outside the O element nucleus in the complexing agent, so that the metal ion complex loses the ability of sharing electrons with the metal ion, and thus loses the complexing ability. 3) Affecting the shape distribution of total nitrogen compounds and the reaction difficulty, from NH₄ ⁺As can be seen from fig. 6, at a pH of 9.26, ammonium nitrogen in the solution coexists in the form of ammonium ions and ammonia water, and is easily volatilized in the form of ammonia gas during the treatment, thereby causing secondary pollution to the environment; meanwhile, according to the nitrate radical half-reaction equation, the reduction of the pH value is beneficial to the reduction of nitrate radicals.

Wherein, the semi-reaction equation of nitrate radical is as follows:

therefore, the optimal pH value of the complexing agent when the complexing agent is acetylacetone is obtained through experiments. By regulating the pH value, the degradation rate can be obviously improved, so that the pollutants can be deeply degraded step by step, in particular the degradation of total nitrogen in the pollutants.

Preferably, the pH is controlled between 6 and 9, more preferably 8, and the specific pH is adjusted according to the kind of the treated pollutant, and if only for organic pollutants, it is preferable that the pH is in the range of 8 to 12, and if the total nitrogen in the pollutant is reduced, the pH should be properly reduced, such as between 2 and 5, according to the principle analysis of fig. 6.

Although the pH value is not preferably too high when total nitrogen is degraded, and the pH value is low to facilitate nitrate reduction, if the pH value is too low, the effect of degradation may be affected due to the influence on the reducing ability and coordinating ability of AA, and therefore, the pH value is preferably controlled within a proper pH range.

The persulfate of the invention can be one or more of sodium persulfate, potassium persulfate and ammonium persulfate, preferably sodium persulfate or potassium persulfate or a mixture of sodium persulfate and potassium persulfate, and the ferrous iron source of the ferrous ions can be any one of ferrous sulfate heptahydrate, ferrous acetate and ferrous chloride tetrahydrate, preferably ferrous sulfate heptahydrate or ferrous chloride tetrahydrate.

In addition, it should be noted that, in the step (B) of the present invention, each operation parameter is controlled, the degradation reaction time of the present invention is about 5-60min, so as to complete the degradation, improve the degradation efficiency, and save the operation time, in the prior art, other degradation methods may require 2-3h, even 7-8h to complete the degradation, compared with the present invention, the degradation method has the advantages of short degradation reaction time, excellent degradation effect, and the synchronous degradation of COD and total nitrogen can be realized under the optimized condition.

Preferably, the degradation treatment time is controlled to be between 10 and 30 min.

Preferably, the temperature of the degradation treatment is controlled between 20 and 35 ℃, more preferably 30 ℃.

Preferably, the degradation treatment mode comprises one or more of standing, stirring, shaking and ultrasonic treatment. The optimal treatment mode is that the degradation treatment is carried out by standing, stirring, shaking and ultrasonic treatment in sequence.

Preferably, the rate of oscillation is controlled between 200 and 250rpm, more preferably 210 rpm.

Preferably, the ultrasonic power is at 40W.

By adopting the stirring degradation method, the degradation rate of total nitrogen reaches more than 85 percent, and the degradation rate of p-chlorophenol reaches more than 95 percent.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention relates to an advanced oxidation reaction system for deeply degrading pollutants (including organic pollutants in wastewater and nitrogen-containing pollutants) by using acetylacetone and ferrous ion to activate persulfate, which mainly comprises acetylacetone and Fe²⁺And persulfate to form a complex activated persulfate system. The system can effectively protect and revive Fe in the reaction system²⁺And meanwhile, the acetylacetone can also assist in activating the persulfate, so that the aims of continuously, stably and efficiently activating the persulfate and reducing or avoiding the unnecessary consumption of the persulfate can be fulfilled, and the degradation efficiency and removal effect of COD and TN are improved.

(2) By adopting the degradation method, the degradation rate of the total nitrogen is finally determined to be more than 85 percent, the degradation rate of the p-chlorophenol is determined to be more than 95 percent, the deep degradation can be realized for organic pollutants and inorganic pollutants in various pollution sources with serious urban pollution, the degradation rate is very high, and the method has wide application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a graph showing the degradation rate of p-chlorophenol by the combination of acetylacetone and a ferrous ion-activated persulfate in example 4 of the present invention;

FIG. 2 is a graph showing the degradation rate of acetylacetone in cooperation with a ferrous ion-activated persulfate to degrade total nitrogen in example 5 of the present invention;

FIG. 3 shows Fe alone in Experimental example 2 of the present invention²⁺An experimental result chart of total nitrogen degradation by activated persulfate;

FIG. 4 is a graph showing the results of experiments in Experimental example 2 of the present invention in which AA alone activates persulfate to degrade total nitrogen;

FIG. 5 is a diagram showing an activation mechanism of a reductive complexing agent in cooperation with a ferrous ion activated persulfate in Experimental example 2;

FIG. 6 shows NH4 after degradation of nitrogen-containing compounds at various pH values according to the present invention⁺-graph of the variation of N.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

1) Selection of iron ion source:

the ferrous iron source selected in this example was ferrous sulfate heptahydrate.

2) Selection of persulfate:

the persulfate salt selected in this example was sodium persulfate.

3) Selection of complexing agent: acetylacetone

4) The specific degradation process is implemented according to the following steps:

adding acetylacetone into p-chlorophenol aqueous solution (concentration is 20 mg/L) with pH value adjusted within 10-12: fe²⁺: the molar ratio of sodium persulfate is 1:20:8, the total volume is 50ml, and the reaction degradation is carried out by shaking for 25min on a shaker at 30 ℃ and 200 rpm;

3ml of the solution after reaction and degradation is put into a 10ml centrifuge tube, extracted by equal volume of ethyl acetate, filtered by a 0.22um water system filter membrane, and the degradation rate of the parachlorophenol (4-CP) is detected to be 95 percent by high performance liquid characterization for 20 min. The reaction system is used for treating the landfill leachate concentrated solution, the COD removal rate of the landfill leachate nanofiltration concentrated solution is 93 percent, and the total nitrogen removal rate is 85 percent.

Example 2

1) Selection of iron ion source:

the ferrous iron sources selected in this example were ferrous acetate and ferrous sulfate heptahydrate.

2) Selection of persulfate:

the persulfate salt selected in this example was sodium persulfate.

3) Selection of complexing agent: acetylacetone

adding acetylacetone into p-chlorophenol water solution (concentration is 20 mg/L) with pH value adjusted within 8-9: fe²⁺: the molar ratio of sodium persulfate is 5:1:1, the total volume is 50ml, and the reaction degradation is carried out by shaking the shaking table at 35 ℃ and 210rpm for 30 min;

3ml of the solution after reaction and degradation is put into a 10ml centrifuge tube, extracted by equal volume of ethyl acetate, filtered by a 0.22um water system filter membrane, and characterized by high performance liquid chromatography for 20min, and the degradation rate of the parachlorophenol (4-CP) is 96 percent. The reaction system is used for treating the landfill leachate concentrated solution, the COD removal rate of the landfill leachate nanofiltration concentrated solution is 94 percent, and the total nitrogen removal rate is 84 percent.

Example 3

1) Selection of iron ion source:

the ferrous iron source of choice in this example was ferrous chloride tetrahydrate.

2) Selection of persulfate:

the persulfate salts selected in this example were potassium persulfate and sodium persulfate.

3) Selection of complexing agent: acetylacetone

adding acetylacetone into p-chlorophenol water solution (concentration is 20 mg/L) with pH value adjusted within 8-9: fe²⁺: the molar ratio of sodium persulfate is 2:15:7, the total volume is 50ml, and the reaction degradation is carried out by shaking the shaking table at 20 ℃ and 250rpm for 60 min;

3ml of the solution after reaction and degradation is put into a 10ml centrifuge tube, extracted by equal volume of ethyl acetate, filtered by a 0.22um water system filter membrane, and the degradation rate of the parachlorophenol (4-CP) is detected to be 98 percent by high performance liquid characterization for 20 min. The reaction system is used for treating the landfill leachate concentrated solution, the COD removal rate of the landfill leachate nanofiltration concentrated solution is 95 percent, and the total nitrogen removal rate is 86 percent.

Example 4

2) Selection of persulfate:

the persulfate salt selected in this example was ammonium persulfate.

3) Selection of complexing agent: acetylacetone

adding acetylacetone into p-chlorophenol water solution (concentration is 20 mg/L) with pH value adjusted within 8-9: fe²⁺: the molar ratio of sodium persulfate is 2:2:1, the total volume is 50ml, and the reaction degradation is carried out by shaking the shaking table at 26 ℃ and 250rpm for 60 min;

3ml of the solution after reaction and degradation is put into a 10ml centrifuge tube, extracted by equal volume of ethyl acetate, filtered by a 0.22um water system filter membrane, and the degradation rate of the parachlorophenol (4-CP) is detected to be 100 percent by high performance liquid characterization for 20 min. The reaction system is used for treating the landfill leachate concentrated solution, the COD removal rate of the landfill leachate nanofiltration concentrated solution is 97 percent, the total nitrogen removal rate is 86 percent, and the specific degradation graph of 4-CP is shown in figure 1.

Example 5

2) Selection of persulfate:

the persulfate salt selected in this example was sodium persulfate.

3) Selection of complexing agent: acetylacetone

50ml of nitrogen-containing aqueous solution with the pH value adjusted to 4-5, the nitrate state potassium concentration of 8g/L and the ammonium sulfate concentration of 10g/L is taken, and acetylacetone: fe²⁺: molar ratio of sodium persulfate 3: 10: 4, oscillating at 210rpm for 10min at 30 ℃, carrying out ultrasonic treatment at 40w for 10min, and standing for 20min for reaction and degradation; the total nitrogen removal rate is over 85% by measuring 1ml sample solution with total nitrogen kit, and the specific total nitrogen degradation curve is shown in figure 2.

Example 6

2) Selection of persulfate:

the persulfate salt selected in this example was sodium persulfate.

3) Selection of complexing agent: acetylacetone

50ml of nitrogen-containing aqueous solution with the pH value adjusted to 2-4, the nitrate state potassium concentration of 16g/L and the ammonium sulfate concentration of 4g/L is taken, and acetylacetone: fe²⁺: molar ratio of sodium persulfate 3: 12: 5, stirring for 5min at 40 ℃, shaking for 10min at 220rpm, carrying out ultrasonic treatment for 10min at 40w, standing for 10min, and carrying out reaction degradation; 1ml of sample liquid is taken and measured by a total nitrogen kit, and the total nitrogen removal rate is more than 92 percent.

Comparative example 1

The specific procedure was identical to example 5 except that acetylacetone: fe²⁺: molar ratio of sodium persulfate 20: 7: 4, the pH value of the system is 1, the degradation time is 3h, and the total nitrogen removal rate is 70% through the determination of a total nitrogen kit.

Comparative example 2

The specific procedure was identical to example 5 except that acetylacetone: fe²⁺: molar ratio of sodium persulfate 1: 70: 1, the pH value of the system is 11, the degradation time is 5h, and the total nitrogen removal rate is 75% through the determination of a total nitrogen kit.

Comparative example 3

The specific procedure was in accordance with example 5, except thatAcetylacetone: fe²⁺: sodium persulfate molar ratio 4: 3: 0.7, the pH value of the system is 1, the degradation time is 3h, and the total nitrogen removal rate is 75 percent through the determination of a total nitrogen kit.

As can be seen from the attached drawings 1-2, only if all parameters are controlled within the scope of the scheme of the invention, the ideal degradation effect can be achieved, not only the degradation effect on organic pollutants is excellent, but also the degradation effect on total nitrogen is very excellent, so that if a certain parameter is not controlled within the scope required by the invention, the ideal degradation effect, especially the pH value, can not be achieved even if the time of the degradation reaction is prolonged, and parameters such as the dosage of all substances in the system and the like need to be matched and are all prepared within the excellent scope, and if the pH value is controlled within the scope of the invention, the dosage adopts the condition of any proportion, although the degradation effect is achieved, the degradation rate is not high.

Experimental example 1

The actual sewage treated by the ferrous coordination system activated persulfate in the embodiment 5 of the invention is compared with other process systems in the prior art in degradation experiments, and the specific experiment results are shown in the following table 1:

TABLE 1 results of the experiment

Conditions of the experiment	Treatment time (h)	COD degradation Rate (%)
			Persulfate deep catalytic oxidation landfill leachate membrane concentrated solution	7	80
Optimization of technological parameters of tail water of leachate oxidized by ferrous activated persulfate	12	60
			Iron-containing compound activated persulfate treatment landfill leachate biochemical tail water	12	60
Processing method adopted in example 5	0.16	85

The method for degrading organic pollutants has the advantages of relatively low cost, simple operation process, easy large-scale implementation, realization of industrial production, effective reduction of COD (chemical oxygen demand) and good effect on deep degradation of nitrogen-containing pollutants such as total nitrogen degradation, and other examples can obtain the same effect after the tests.

Experimental example 2

The functions of AA reactivation and auxiliary persulfate activation are tested, and the specific experimental process is as follows:

in the advanced oxidation process, the activator Fe²⁺Is easy to be oxidized to generate Fe³⁺Deactivation, resulting in termination of oxidative degradation. However, when acetylacetone (AA) is present in the system, AA can convert Fe³⁺Reduction to Fe²⁺Thereby realizing Fe²⁺The revival of (1).

Fe from FIG. 3²⁺As can be seen from the degradation plots of the degradation system alone and the acetylacetone system alone of FIG. 4, the reducibility of AA is slightly higher than that of ferrous iron, and if the subsequent reaction proceeds, AA is capable of converting Fe³⁺Reduction to Fe²⁺Thereby realizing Fe²⁺The practice proves that the acetylacetone can not only react with Fe²⁺Coordinate, and can also reduce Fe³⁺。

AAThe reduction results of (A) show that AA has reduced Fe²⁺Reactivation effect, thereby being beneficial to the activator Fe of the advanced oxidation system²⁺The activity is maintained, and the oxidative degradation of pollutants can be continuously and efficiently carried out.

Fe alone²⁺The effect of degrading nitrogen in the water phase with acetylacetone alone is not ideal, but when the two exist at the same time, Fe in the solution proceeds along with the reaction²⁺The concentration decreases and the coordination equilibrium shifts in the dissociation direction, thus releasing Fe²⁺On the contrary, when Fe³⁺Is reduced to produce Fe²⁺The coordination equilibrium is shifted in the direction of the formation of the complex, Fe²⁺The amount is reduced. The result is that the coordination balance realizes the system Fe²⁺A dynamic equilibrium of concentrations. Therefore, continuous and stable excitation can be realized in the system, and a premise is provided for continuous and stable degradation of nitrate nitrogen and ammonium nitrogen in the system.

In addition, the activation mechanism of acetylacetone in cooperation with ferrous ion to activate persulfate according to the present invention is shown in fig. 5 below.

While particular embodiments of the present invention have been illustrated and described, it would be obvious that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. The system is characterized in that acetylacetone and Fe are combined to activate persulfate²⁺And persulfate;

acetylacetone: fe²⁺: the molar ratio between the persulfates is controlled between (1 and 5): (1-20): (1-8);

the acetylacetone in the activated persulfate system has the same Fe with the activated persulfate system²⁺Coordination, reactivation Fe²⁺And functions to assist in the activation of persulfate.

2. The activated persulfate system according to claim 1, wherein the molar ratio of acetylacetone: fe²⁺: the molar ratio between the persulfates is controlled between (2 and 4): (4-15): and (2) to (7).

3. The activated persulfate system according to claim 2, wherein the molar ratio of acetylacetone: fe²⁺: the molar ratio between the persulfates is controlled to be 3: 10: 4 in the middle.

4. A process for the removal of contaminants by activating a persulfate system as recited in any one of claims 1 to 3, including the steps of:

(A) adding a ferrous coordination activated persulfate system into wastewater containing organic pollutants and nitrogen-containing pollutants to be treated, and controlling the pH value of a reaction system to be between 2 and 12;

(B) degrading at 15-50 deg.C for 5-60 min.

5. The method according to claim 4, wherein in the step (A), the pH value of the system is controlled to be 6-9.

6. The method according to claim 4, wherein in the step (A), the pH value of the system is controlled to be 8.

7. The method according to claim 4, wherein in the step (A), the persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate.

8. The method according to claim 4, wherein in the step (A), the persulfate is either one or both of sodium persulfate and potassium persulfate.

9. The method according to claim 4, wherein in step (A), the Fe²⁺The ferrous iron source is one of ferrous sulfate heptahydrate, ferrous acetate and ferrous chloride tetrahydrate.

10. The method according to claim 4, wherein in step (A), the Fe²⁺The ferrous iron source is ferrous sulfate heptahydrate or ferrous chloride tetrahydrate.

11. The method according to claim 4, wherein in the step (B), the temperature of the degradation treatment is controlled to be 20-35 ℃.

12. The method according to claim 4, wherein in the step (B), the temperature of the degradation treatment is controlled to 30 ℃.

13. The method according to claim 4, wherein in the step (B), the time of the degradation treatment is controlled to be between 10 and 30 min.

14. The method according to claim 4, wherein in the step (B), the degradation treatment comprises one or more of standing, stirring, shaking and ultrasound.

15. The method as claimed in claim 14, wherein the oscillating speed is between 200 and 250 rpm.

16. The method of claim 14, wherein the oscillating is at a rate of 210 rpm.

17. The method of claim 14, wherein the ultrasound has a power of 40W.

18. The method according to claim 14, wherein in the step (B), after the degradation by stirring, the degradation rate of total nitrogen is measured to be more than 85%, and the degradation rate of p-chlorophenol is measured to be more than 95%.