CN116143337A - Method for treating acetone-containing high-fluorine wastewater - Google Patents

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a method for treating high-fluorine wastewater containing acetone, which solves the problems of complex preparation process, higher preparation cost, poor strength, poor corrosion resistance and poor anti-fouling performance of a membrane material in the prior art, and the defects limit the application of the membrane material in high-salt wastewater treatment. The method for treating the acetone-containing high-fluorine wastewater comprises a chemical precipitation method, a reverse osmosis method, a coagulating sedimentation method, an adsorption method and an electrodialysis method, wherein the chemical precipitation method is the most common treatment by adopting a calcium salt precipitation method, and nitrate lime and calcium chloride are added into the wastewater. The invention divides the adsorbent into iron-based adsorbent, aluminum-based adsorbent, rare earth adsorbent, biological adsorbent and the like, and the reverse osmosis method can very effectively and reliably realize the dual purposes of defluorination and desalination of high-fluorine brackish water.

Description

A method for the treatment of acetone-containing high-fluorine wastewater

technical field

The invention relates to the technical field of wastewater treatment, in particular to a method for treating wastewater containing acetone and high fluorine.

Background technique

Wastewater treatment is to use physical, chemical and biological methods to treat wastewater, purify wastewater, reduce pollution, and achieve wastewater recycling and reuse, making full use of water resources. Fluorine is one of the most widely distributed elements on the earth. Among the elements, the abundance of fluorine ranks 13th, accounting for 0.06-0.09% of the earth's crust. The chemical properties of fluorine are very active and can interact with almost all elements, so most of the fluorine in the earth's crust exists in the form of compounds.

The treatment of waste water containing high fluorine in acetone mainly adopts thermal concentration process, such as multi-effect evaporation. The principle of this process is to use heat energy to concentrate waste water containing high fluorine in acetone to obtain concentrated water and clean water. This process consumes a lot of energy and requires an area of Large and large equipment, at the same time, the fluoride ions in the wastewater are easy to corrode and scale the equipment, reduce the treatment efficiency of the equipment, and increase the maintenance and maintenance costs of the equipment. Membrane separation technology effectively combines the effective filtration performance of the membrane with the traditional multi-effect evaporation technology, which makes up for the shortcomings of the traditional multi-effect evaporation technology. It has the characteristics of low energy consumption, good quality, less pollution, simple process, and simple operation. It has gradually Replacing traditional multi-effect evaporation has become the mainstream technology in the industry. However, the preparation process of membrane materials in the prior art is complicated, the preparation cost is high, the strength is poor, the corrosion resistance is poor, and the anti-fouling performance is poor. These defects limit its application in high-salt wastewater. Processing applications.

Contents of the invention

The purpose of the present invention is to provide a method for the treatment of acetone-containing high-fluorine wastewater, which solves the problems of complex preparation process, high preparation cost, poor strength, poor corrosion resistance and poor anti-fouling performance of membrane materials in the prior art. Defects limit its application in high-salt wastewater treatment.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for treating acetone-containing high-fluorine wastewater, including chemical precipitation, reverse osmosis, coagulation precipitation, adsorption, and electrodialysis. Among them, the chemical precipitation method is the most common calcium salt precipitation method. Add salt lime and calcium chloride to make F- and Ca2+ in the wastewater react to form CaF2 precipitation and remove it, which is especially common in the pretreatment of high-concentration fluorine-containing wastewater. The chemical precipitation method is simple and low in treatment costs, but there are secondary Pollution problem, and the treatment effect is not ideal. The fluoride content in the effluent is around 15-30mg/L. The principle is that F- can form various complexes from AlF2+ to AlF63- with Al3+, and F- can be removed by sedimentation. .

Preferably, the coagulation-sedimentation method is to add a coagulant in the fluorine-containing wastewater, and adjust it to an appropriate pH with an alkali to form a hydroxide colloid to absorb fluorine. The coagulants commonly used in this method can be divided into two categories: one It is an inorganic coagulant. Aluminum salt, iron salt, calcium compound and magnesium compound are often used. After the coagulant is put into water, its metal ions will form fine glue nuclei or flocs. Precipitation, so as to achieve the purpose of defluoridation, the other is organic coagulant, commonly used is polyacrylamide, in this method, aluminum salt and iron salt coagulation method are most widely used, suitable for the treatment of industrial wastewater, aluminum sulfate, Aluminum salts such as polyaluminum have good coagulation and removal effects on fluoride ions.

Preferably, the reverse osmosis technology is a kind of membrane separation technology that has been developed rapidly in the past few years. The reverse osmosis membrane can only selectively pass through the solvent and intercept ionic substances. The pressure difference on both sides of the membrane is used as the driving force to restrain The osmotic pressure of the solvent is the process of separating the liquid mixture by the solvent through reverse osmosis. In essence, this method has no selectivity, and only removes F- together during the desalination process.

Preferably, the adsorption phenomenon refers to the phenomenon that the molecules, atoms or ions of a substance can automatically attach to the surface of the solid under certain conditions, or the phenomenon that the concentration of the substance changes automatically in the interface layer. Fluorine mainly diffuses to the surface of the solid adsorbent through F- in water, bonds with the surface of the adsorbent or is only adsorbed on the surface by relatively weak intermolecular forces.

Preferably, the defluorination process of adsorption of aluminum salt flocculation precipitation is electrostatic adsorption, and because AC or PAC fluorine-containing flocs adsorb charged fluorine ions, the positive charge is partially neutralized, and the potential is higher than that of the flocs themselves under the same pH condition. to be low.

Preferably, the commonly used adsorbents for fluorine removal mainly include activated alumina, clinoptilolite, and activated magnesia. The adsorbents can treat wastewater with a fluorine concentration of 10 mg/L to below 1 mg/L, reaching the standard for drinking water.

The present invention at least has the following beneficial effects:

The adsorption capacity of the adsorbent among the present invention is on the low side, such as the adsorption capacity of clinoptilolite to fluoride ion is about 20 mg/g, and the adsorption capacity of activated alumina is no more than 2mg/g, therefore, it is very critical to select a suitable adsorbent in the adsorption method. Commonly used adsorbent materials include rare earth elements, active materials, composite materials, nanomaterials, iron-aluminum and their compounds, etc. According to different raw materials, adsorbents can also be divided into iron-based adsorbents, aluminum-based adsorbents, rare earth adsorbents, Reverse osmosis can effectively and reliably achieve the dual purpose of defluoridation and desalination of high-fluoride brackish water.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Embodiment one

Including chemical precipitation method, reverse osmosis method, coagulation precipitation method, adsorption method, and electrodialysis method, among which the chemical precipitation method is the most common method of calcium salt precipitation, adding salt lime and calcium chloride to the wastewater to make the wastewater The F- and Ca2+ react to form CaF2 precipitation and remove it, which is especially common in the pretreatment application of high-concentration fluorine-containing wastewater. The chemical precipitation method is simple and the treatment cost is low, but there are secondary pollution problems, and the treatment effect is not ideal. The fluoride content in the effluent is around 15-30 mg/L. The principle is that F- can form various complexes from AlF2+ to AlF63- with Al3+, etc., and F- can be removed by sedimentation.

Embodiment two

The coagulation precipitation method is to add a coagulant to the fluorine-containing wastewater, and adjust it to an appropriate pH with alkali to form a hydroxide colloid to absorb fluorine. The coagulants commonly used in this method can be divided into two categories: one is inorganic mixed Coagulant, aluminum salt, iron salt, calcium compound and magnesium compound are often used. After the coagulant is put into water, its metal ions will form fine glue nuclei or velvet flocs. These flocs absorb fluoride ions and produce coprecipitation, thus To achieve the purpose of defluoridation, the other type is organic coagulant, commonly used is polyacrylamide, in which aluminum salt and iron salt coagulation method are most widely used, suitable for the treatment of industrial wastewater, aluminum sulfate, polyaluminum, etc. Aluminum salts have good coagulation and removal effects on fluoride ions.

Embodiment Three

Reverse osmosis technology is a kind of membrane separation technology that has been developed rapidly in the past few years. The reverse osmosis membrane can only selectively pass through the solvent and intercept ionic substances. The pressure difference on both sides of the membrane is used as the driving force to restrain the penetration of solvents. Pressure, the process of separating the liquid mixture by making the solvent through reverse osmosis, in essence, this method is not selective, but F- is also removed during the desalination process.

Embodiment Four

Adsorption phenomenon refers to the phenomenon that molecules, atoms or ions of a substance can automatically attach to the surface of a solid under certain conditions, or the phenomenon that the concentration of a substance changes automatically in the interface layer. The use of adsorption materials to reduce fluorine is mainly F- diffuses to the surface of the solid adsorbent through the water, bonds with the surface of the adsorbent or is only adsorbed on the surface by relatively weak intermolecular forces.

Embodiment five

The defluorination process of adsorption aluminum salt flocculation precipitation is electrostatic adsorption, and AC or PAC fluorine-containing flocs adsorb charged fluorine ions, the positive charge is partially neutralized, and the potential is lower than that of the flocs themselves under the same pH conditions.

Commonly used adsorbents for fluoride removal mainly include activated alumina, clinoptilolite, and activated magnesia. The adsorbents can treat wastewater with a fluorine concentration of 10 mg/L to below 1 mg/L, reaching the standard for drinking water.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description are only the principles of the present invention. Variations and improvements, which fall within the scope of the claimed invention. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. A method for treating high-fluorine wastewater containing acetone comprises a chemical precipitation method, a reverse osmosis method, a coagulating sedimentation method, an adsorption method and an electrodialysis method, wherein the chemical precipitation method is the most common treatment by adopting a calcium salt precipitation method, nitrolime and calcium chloride are added into the wastewater to make F-in the wastewater and Ca2+ in counter reaction form CaF2 precipitate for removal, the method is particularly common in the application of pretreatment of high-concentration fluorine-containing wastewater, the chemical precipitation method is simple, the treatment cost is low, but the problem of secondary pollution exists, the treatment effect is also less ideal, the fluoride content of the effluent is 15-30 mg/L, and the principle is that F-can form various complexes ranging from AlF2+ to AlF63-with Al3+ and the like, and F-is removed by sedimentation.

2. The method for treating wastewater containing acetone and high fluorine according to claim 1, wherein the coagulating sedimentation method is characterized in that coagulant is added into wastewater containing fluorine, alkali is used for adjusting the pH to a proper value to enable the wastewater to form hydroxide colloid to adsorb fluorine, the coagulant commonly used in the method can be divided into two types, namely inorganic coagulant, aluminum salt, ferric salt, calcium compound and magnesium compound, metal ions of the coagulant can form fine colloid cores or flock flocs after the coagulant is put into water, the flocs adsorb fluorine ions to generate coprecipitation, and thus the purpose of removing fluorine is achieved, the other type is organic coagulant, and polyacrylamide is commonly used.

3. The method for treating wastewater containing acetone and high fluorine according to claim 1, wherein the reverse osmosis technology is a membrane separation technology which has been rapidly developed in the past, the reverse osmosis membrane has the characteristic of selectively allowing only solvent to permeate therethrough and blocking ionic substances, the osmotic pressure of the solvent is restrained by taking the pressure difference between two sides of the membrane as the driving force, and the solvent is separated from the liquid mixture by reverse osmosis, so that the method is essentially non-selective and only removes F-together in the desalting process.

4. The method for treating wastewater containing acetone and high fluorine according to claim 1, wherein the adsorption phenomenon is a phenomenon that molecules, atoms or ions of a substance can be automatically attached to the surface of a solid under certain conditions, or a phenomenon that the concentration of the substance in an interface layer is automatically changed, and fluorine is reduced by using an adsorption material, mainly through F-diffusion in water to the surface of the solid adsorbent, and is bonded with the surface of the adsorbent or is only adsorbed on the surface through a relatively weak intermolecular force.

5. The method for treating acetone-containing high-fluorine wastewater according to claim 1, wherein the flocculation precipitation defluorination process of the adsorption aluminum salt is electrostatic adsorption, and the positive charges of the AC or PAC fluorine-containing flocs are partially neutralized due to the adsorption of charged fluorine ions, and the electric potential is lower than that of the AC or PAC fluorine-containing flocs under the same pH condition.

6. The method for treating acetone-containing high-fluorine wastewater according to claim 1, wherein the common adsorbent for removing fluorine mainly comprises activated alumina, clinoptilolite and activated magnesia, and the adsorbent can treat wastewater with fluorine concentration of 10mg/L to below 1mg/L to reach the standard of drinking water.