1. A preparation method of a fluorine removal medicament for water treatment is characterized by comprising the following steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in a fixed amount of water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature to be 40-60 ℃, quickly stirring for 10-30 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is = 4.0-5.0, stirring for 20-40 minutes, and standing for 10-30 minutes after the reaction is finished to obtain a solution A;

step two: weighing a first fixed amount of aluminum chloride hexahydrate solid, slowly adding the first fixed amount of aluminum chloride hexahydrate solid into the solution A under the condition of continuous stirring, gradually changing the solution from turbid to clear, stirring for 10-30 minutes, continuously weighing a second fixed amount of ferric chloride hexahydrate solid, slowly adding the second fixed amount of ferric chloride hexahydrate solid into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, gradually clarifying the solution after continuous stirring, finally changing the solution into a reddish brown transparent solution, stirring and reacting for 1-2 hours, stopping stirring, standing for 3-5 hours, and curing to obtain a solution B;

step three: measuring a fixed amount of sodium carboxymethylcellulose solid, adding water to dissolve the sodium carboxymethylcellulose solid to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely a solution C;

step four: and (3) putting the prepared solution B and the prepared solution C into a constant-temperature water bath according to a proportion, fully mixing and reacting in a high-speed stirring and heating state, setting the temperature to be 40-80 ℃, stirring at a rotating speed of 400-600 rpm, reacting for 3-5 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

2. The preparation method according to claim 1, wherein the mass ratio of the first fixed amount of aluminum chloride hexahydrate solid to the solution A in the second step is (1-5): 10.

3. The method of claim 1, wherein the first fixed amount of aluminum chloride hexahydrate in step two is in a solid mass to solution a mass ratio of 3: 10.

4. The preparation method according to claim 1, wherein the mass ratio of the second fixed amount of aluminum chloride hexahydrate solid to solution A in the second step is (0.5-2): 10.

5. The method of claim 1, wherein the second fixed amount of aluminum chloride hexahydrate in step two is in a solid mass to solution a mass ratio of 1: 10.

6. The preparation method according to claim 1, wherein the solution B and the solution C are added in the fourth step according to a volume ratio of (20-100): 1.

7. The method according to claim 1, wherein the solution B and the solution C in step four are mixed in a volume ratio of 50:1 is added.

8. A water treatment fluorine removal agent, which is obtained by the preparation method according to any one of claims 1 to 7.

Background

Fluoride is an indispensable production raw material for many chemical products, has huge application amount in industries such as steel smelting, coal chemical industry, electroplating and the like, and often generates a large amount of fluorine-containing wastewater in the production and processing processes of aluminum and chemical fertilizers. The high-concentration fluorine-containing wastewater can meet the discharge standard that the mass concentration of fluoride is lower than 10mg/L in national GB 8978 and 1996 integrated wastewater discharge standard by carrying out multi-stage treatment. For wastewater discharged by inorganic chemical enterprises, the state requires that the fluoride mass concentration is lower than 6 mg/L. The emission limit value of five emission standards in the national GB3838-2002 'surface water environmental quality Standard' III category is lower than 1mg/L, the emission standards of environmental protection bureaus and factories in various regions and cities and the highest allowable concentration of the emission standards in various provinces and cities is lower than 1-2 mg/L, and further the sewage treatment plant reversely limits that various upstream factories generating fluorine-containing wastewater can only discharge lower fluorine-containing wastewater than the conventional factories.

A great deal of application research is carried out on the wastewater defluorination technology at home and abroad, and certain achievements are obtained on the defluorination theory, process and technology at present. However, the industrial waste water is complicated in kind and composition, such as alkaline high-fluorine waste water, acidic high-fluorine waste water, high-salt high-fluorine waste water, etc., and contains Na⁺、Ca²⁺、Mg²⁺、Cl^-、SO4^2-And the like, soluble inorganic salts, organic matters, heavy metals, radioactive substances and the like, so that the wastewater defluorination process has the problems of complicated flow, more added medicaments, high treatment cost and the like. Therefore, a simple, efficient and low-cost wastewater fluorine removal method is sought, and the method has important significance for environmental management and long-term development of human beings.

The fluorine-containing wastewater treatment method has various methods, and the most applied treatment processes in the current engineering are chemical precipitation, flocculation precipitation and adsorption. The electrocoagulation method in the prior defluorination technology has the problem of electrode passivation and aims at the site with large water volumeIt is not practical to use. The application process of the resin ion exchange method is only suitable for treating low-concentration and small-volume fluorine-containing wastewater such as relatively pure tap water, underground water and the like, and is not suitable for large-area popularization. The prior commonly applied traditional lime precipitation process is that Ca (OH) is added₂Or Ca (OH)₂And CaCl₂The mixture of (A) produces CaF which is poorly soluble in water₂Precipitating to form fluoride precipitate, separating solid precipitate to remove fluoride. The use of primary or secondary precipitations is common, with the disadvantage that CaF is formed₂The precipitate will be encapsulated in Ca (OH)₂On the surface of the particles, the utilization efficiency of calcium salt is reduced, the rate of formation of precipitates is slower, the sedimentation characteristics of the precipitates are poorer, if excessive lime is added, the cost of corresponding chemical agents is increased, and the calcium concentration, the pH value and the sludge amount in the effluent are increased. The method has the defects that the removal of fluorine ions is not thorough, cannot reach the environmental protection standard, has the treatment limit, and is only suitable for removing fluorine from wastewater with the fluorine-containing concentration of more than 20 mg/L.

In the prior art, for example, chinese patent application No. 201910354307.4 discloses a preparation method of an iron-aluminum composite bone charcoal fluorine removal agent and the prepared fluorine removal agent, and the preparation method comprises the following steps: (1) cleaning the surface of the livestock bone, and carbonizing at 400-450 ℃ for 1.5-2 h to obtain bone charcoal; (2) cooling the bone charcoal obtained in the step (1), grinding and sieving, washing with water, and drying to obtain bone charcoal granules; (3) fe with the mass percent concentration of 2-8% is added to the bone char particles obtained in the step (2) according to the solid-to-liquid ratio of 1: 2.5-1: 10₂(SO₄)₃Soaking the aluminum alloy in the solution for 0.3-0.7 h, washing with water, drying, and then adding 3-10% Al by mass percent according to the solid-to-liquid ratio of 1: 3-1: 8₂(SO₄)₃Soaking the aluminum alloy in the solution for 0.5 to 1.5 hours, washing and drying the aluminum alloy to obtain Al₂(SO₄)₃-Fe₂(SO₄)₃Compound bone charcoal defluorinating agent. The method has complex preparation process and harsh process conditions, and is not beneficial to large-scale quantitative production.

Based on the above, research and development of a novel deep fluorine removal agent are urgently needed to improve the removal effect of fluorine ions in a fluorine-containing water body so as to meet increasingly strict fluorine-containing sewage discharge standards.

Disclosure of Invention

The invention mainly aims to overcome the defects in the prior art and provide a water treatment defluorination medicament and a preparation method thereof. The defluorination medicament provided by the invention takes sodium silicate, dilute hydrochloric acid, aluminum chloride hexahydrate, ferric chloride hexahydrate and sodium carboxymethylcellulose as raw materials, the defluorination rate of the deep defluorination medicament provided by the invention can reach more than 95%, even when low-concentration fluorine-containing wastewater (less than or equal to 15mg/L) is treated, the defluorination rate of fluoride ions can reach more than 95% after stirring reaction for 15 minutes, the fluorine content in effluent can reach the class III first-level discharge standard of the national surface water environment quality standard (GB 3838-2002), the defluorination rate is high, the defluorination effect is obvious, and the deep defluorination of the fluorine-containing wastewater can be realized.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme.

The invention provides a preparation method of a fluorine removal medicament for water treatment, which is characterized by comprising the following steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in a fixed amount of water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature to be 40-60 ℃, quickly stirring for 10-30 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is = 4.0-5.0, stirring for 20-40 minutes, and standing for 10-30 minutes after the reaction is finished to obtain a solution A;

step two: weighing a first fixed amount of aluminum chloride hexahydrate solid, slowly adding the first fixed amount of aluminum chloride hexahydrate solid into the solution A under the condition of continuous stirring, gradually changing the solution from turbid to clear, stirring for 10-30 minutes, continuously weighing a second fixed amount of ferric chloride hexahydrate solid, slowly adding the second fixed amount of ferric chloride hexahydrate solid into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, gradually clarifying the solution after continuous stirring, finally changing the solution into a reddish brown transparent solution, stirring and reacting for 1-2 hours, stopping stirring, standing for 3-5 hours, and curing to obtain a solution B;

step three: measuring a fixed amount of sodium carboxymethylcellulose solid, adding water to dissolve the sodium carboxymethylcellulose solid to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely a solution C;

step four: and (3) putting the prepared solution B and the prepared solution C into a constant-temperature water bath according to a proportion, fully mixing and reacting in a high-speed stirring and heating state, setting the temperature to be 40-80 ℃, stirring at a rotating speed of 400-600 rpm, reacting for 3-5 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Preferably, the mass ratio of the first fixed amount of aluminum chloride hexahydrate solid to the solution A in the second step is (1-5): 10.

Preferably, the mass ratio of the first fixed amount of aluminum chloride hexahydrate solid to the solution A in the second step is 3: 10.

Preferably, the mass ratio of the second fixed amount of aluminum chloride hexahydrate solid to the solution A in the second step is (0.5-2): 10.

Preferably, the mass ratio of the second fixed amount of aluminum chloride hexahydrate solid to the solution A in the second step is 1: 10.

Preferably, the solution B and the solution C in the fourth step are added according to the volume ratio of (20-100): 1.

Preferably, the solution B and the solution C in the fourth step are mixed according to a volume ratio of 50:1 is added.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme.

The invention also provides a water treatment fluorine removal agent, which is characterized by being prepared according to the preparation method.

By the technical scheme, the invention at least has the following advantages:

1. the invention prepares the high-efficiency defluorination medicament CF-1 by selecting proper reaction conditions and optimizing the component proportion, and when the defluorination medicament is used for treating low-concentration fluorine-containing wastewater (less than or equal to 15mg/L), the defluorination medicament can ensure that the removal rate of fluorine ions reaches more than 95 percent after stirring reaction for 5-15 minutes, and has high defluorination rate and obvious defluorination effect.

2. The pH range is regulated and controlled by controlling the adding amount of hydrochloric acid in the preparation process of the medicament, so that the activation effect of the solution is ensured, the system acidity is effectively controlled, the complexing effect of metal nuclear ions on fluoride is enhanced, and the flocculation capacity of the whole medicament is ensured.

3. The aluminum generated by the reaction in the deep fluorine removal agent CF-1 mainly plays a role in adsorption and flocculation, and is polymerized by hydroxyl cation [ Al₁₃O₄(OH)₂₄]⁷⁺The form exists, the form has high charge density and medium polymerization degree, and the hydroxyl sites of the form are promoted to be rapidly contacted with F in the wastewater^-Complexing to form a stable complex; meanwhile, the positive charge density is reduced, so that the aggregation and precipitation of the complex are accelerated, and the conversion from free fluorine to granular fluorine is realized. The existence of the ferric salt plays a role in adsorption flocculation, and simultaneously, the structure of the floc can be changed, so that the specific gravity of the floc is improved, and the sedimentation efficiency is improved.

4. In the deep defluorination medicament CF-1, pollutants in wastewater are quickly flocculated by positive charges carried by aluminum salts combined on a carboxymethyl cellulose chain in the initial stage of defluorination flocculation reaction through a double electric layer compression process, then, polyhydroxy-rich cellulose polymer chains play roles of bridging and net capturing and sweeping to enable formed fluorine-containing solid particles to be mutually adsorbed and quickly flocculated into large flocculating constituents, and meanwhile, the flocculating constituents are utilized to generate strong adsorption on fluorine ions to realize the synergistic further removal of the fluorine ions, and because of the high molecular weight of the medicament, the quick sedimentation is realized by increasing the specific gravity of the flocculating constituents, and the aim of solid-liquid separation is fulfilled.

5. The sodium carboxymethylcellulose in the deep fluorine removal agent CF-1 is derived from common building industry application, and the special polyhydroxy of the sodium carboxymethylcellulose can be well compounded with the aluminum salt, so that the probability of generating free radicals by catalyzing micro organic pollutants in water by aluminum ions is greatly reduced, and the toxicity of the aluminum salt is reduced to the maximum extent or even eliminated.

6. No secondary pollution. The sodium carboxymethyl cellulose is used as a raw material, so that the residue of the flocculant is easily degraded by microorganisms in the environment, and the problem of secondary pollution is solved.

7. The preparation method is simple. The method has low requirement on equipment, mild reaction conditions and simple manufacturing process, can achieve better treatment effect by properly adjusting the dosage according to different treatment objects and sewage properties, and is easy to realize industrialization.

The foregoing is a summary of the present invention, and in order to provide a clear understanding of the technical means of the present invention and to be implemented in accordance with the present specification, the following is a detailed description of the preferred embodiments of the present invention.

Detailed Description

In order to make the technical means, the creation features, the achievement purposes and the effects of the invention easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The fluorine removal agent CF-1 was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.5, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 3: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 1: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 50:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Example 2

The fluorine removal agent CF-2 was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.0, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 2: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 1.5: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 60:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Example 3

The fluorine removal agent CF-3 was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.3, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 4: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 0.5: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 80:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Example 4

The fluorine removal agent CF-4 was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.7, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 5: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 0.5: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 100:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Example 5

The fluorine removal agent CF-5 was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.9, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 1: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 2: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 70:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Comparative example 1

The defluorinating agent was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.5, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of ferric chloride hexahydrate solid, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 2: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 50:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Comparative example 2

The defluorinating agent was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =4.7, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 1: 10. The solution gradually becomes clear from turbidity, the stirring time is 20 minutes, the stirring is stopped, and the solution is kept stand for 4 hours for curing to obtain solution B.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 70:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Comparative example 3

The defluorinating agent was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% to activate until the pH =5.5, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 2: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 1.5: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 60:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Comparative example 4

The defluorinating agent was prepared according to the following experimental procedure. The method comprises the following specific steps:

the method comprises the following steps: weighing a fixed amount of sodium silicate, dissolving the sodium silicate in quantitative water to prepare a sodium silicate solution with the mass concentration of 3-5%, placing the sodium silicate solution in a constant-temperature water bath kettle, setting the constant temperature at 50 ℃, quickly stirring for 20 minutes to obtain a colorless transparent solution, adding a dilute hydrochloric acid solution with the mass concentration of 15% for activation until the pH is =5.0, stirring for reaction for 30 minutes, and standing for 20 minutes after the reaction is finished to obtain a solution A.

Step two: weighing a fixed amount of aluminum chloride hexahydrate solid, and slowly adding the aluminum chloride hexahydrate solid into the solution A under the condition of continuously stirring, wherein the mass ratio of the aluminum chloride hexahydrate solid to the solution A is 4: 10. The solution is gradually changed from turbid to clear, the stirring time is 20 minutes, and a fixed amount of ferric chloride hexahydrate solid is continuously weighed, wherein the mass ratio of the ferric chloride hexahydrate solid to the solution A is 0.5: 10. Slowly adding the mixture into the solution under the condition of continuous stirring, wherein the solution becomes dark and turbid, the solution is gradually clarified after continuous stirring and finally becomes a reddish brown transparent solution, the stirring reaction time is 1.5 hours, and the solution is kept standing for 4 hours for curing after the stirring is stopped, so that the solution B is obtained.

Step three: a fixed amount of sodium carboxymethylcellulose solid is measured and dissolved in water to prepare a transparent viscous sodium carboxymethylcellulose solution with the mass concentration of 4%, namely solution C.

Step four: and (3) placing the prepared solution B and the prepared solution C in a constant-temperature water bath according to the volume ratio of 150:1, stirring and heating at a high speed, fully mixing and reacting, setting the temperature at 60 ℃, stirring at the rotating speed of 500 r/min, reacting for 4 hours, and preparing the final defluorinating medicament solution after the reaction is finished.

Experimental example defluorination effect of defluorinating agent

Before treatment, the pH of wastewater in a certain mine sewage treatment station is =7.9, and the content of fluorine ions exceeds 7.21 mg/L.

The effluent discharge standard of the experimental example implements five discharge standards of III class of the national surface water environment quality standard (GB 3838-2002) and the discharge limit value is lower than 1mg/L, and the fluorine-containing concentration of the effluent after the limited treatment is required to be lower than 1mg/L in the experimental example.

In this experimental example, the fluorine-containing wastewater was treated with the fluorine removal agents prepared in examples 1 to 5 and comparative examples 1 to 4, respectively, to examine the treatment capacity and treatment effect of the fluorine removal agents, and the specific treatment steps were as follows:

adding 1L of fluorine-containing wastewater to be treated into a beaker, respectively adding 1g of the defluorination agent solution prepared in the step 1, setting the rotating speed to be 150r/min, respectively and fully stirring and reacting for 15 minutes, and standing and settling for 10 minutes.

Taking each supernatant to respectively detect the concentration (mg/L) of fluorine in water, wherein the detection method is national environmental protection standard 'determination of water quality fluoride reagent spectrophotometry' (HJ 488-2009), and calculating the defluorination rate (%), and the detection results of each detection solution are shown in the following table 1.

TABLE 1 removal Rate

From the results, the fluorine removal rate of the deep fluorine removal agent can reach more than 95%, even when low-concentration fluorine-containing wastewater (less than or equal to 15mg/L) is treated, the removal rate of fluorine ions can reach more than 95% after stirring reaction for 15 minutes, the fluorine content in effluent can reach the first-level discharge standard, the fluorine removal rate is high, the fluorine removal effect is obvious, and the deep fluorine removal of the fluorine-containing wastewater can be realized.

When the fluorine-containing wastewater is treated by adopting the fluorine removal agent, the effluent effect index can stably reach different discharge standards of China, places and industries, and the fluorine removal agent has multiple effects of removing fluorine, coagulating, removing turbidity and the like. High purity of the medicament, less impurities, less dosage and low sludge amount. High defluorination efficiency, no influence from the change of the quality of the wastewater, high operation stability, low operation cost and safe and convenient operation.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.