Method for promoting deep fluorine removal by complexing agent and treatment method of fluorine-containing wastewater

Abstract

The application discloses a method for promoting deep fluorine removal by a complex fluorine removal agent with a complexing agent and a fluorine-containing wastewater treatment method, and belongs to the wastewater treatment field. The method adds the complexing agent to the complex fluorine removal agent to form a compound fluorine removal agent, improves the efficiency of the complex fluorine removal agent, and avoids cost waste caused by excessive addition of the complex fluorine removal agent. The complexing agent is ethylenediaminetetraacetic acid (EDTA) or / and an EDTA derivative, and the mass ratio of the complex fluorine removal agent to the complexing agent is 10-1:1-10. The complexing agent promotes the removal efficiency of the complex fluorine removal agent on fluorine ions.

Description

Technical Field

[0001] The present invention relates to wastewater treatment, in particular to a method for promoting deep defluorination of a composite defluoridating agent by utilizing a complexing agent and a method for treating fluorine-containing wastewater. Background Art

[0002] With the continuous advancement and upgrading of technology, the application of fluorine resources in photovoltaics and glass manufacturing has become increasingly widespread, leading to the generation of large amounts of fluoride-containing wastewater. Fluoride is a hazardous substance. If fluoride-containing wastewater is not treated promptly, it may not only cause human health problems such as dental fluorosis and skeletal fluorosis, but also cause damage to the ecological environment. Therefore, for the dual considerations of ecological protection and human health, fluoride-containing wastewater treatment is urgently needed.

[0003] Currently, fluoride removal from wastewater in the photovoltaic and glass industries typically uses a two-stage calcium salt precipitation method, which can reduce the fluoride ion concentration in the effluent to 10-20 mg / L. However, excessive addition of calcium salts fails to further reduce fluoride ion concentration and produces a large amount of fluoride-containing sludge. Therefore, to further reduce fluoride ion concentration, a metal salt defluoridator is usually added in a subsequent step.

[0004] Metal salt defluoridators are chemical agents specifically designed to remove fluoride ions from water. They react with fluoride ions to form insoluble precipitates, thereby removing fluoride ions. However, excessive use of these agents does not significantly increase fluoride ion removal and may increase the burden on subsequent filter press systems.

[0005] Therefore, finding a method to promote the effective removal of fluoride ions by metal defluoridators is a key technical challenge that determines their further development. The present invention aims to find a simple method or agent to improve the removal performance of metal defluoridators while ensuring that the fluoride ion concentration and pH value in the treated water meet discharge standards.

[0006] The above background technology is for facilitating understanding of the present invention and is not a known technology disclosed to the general public before the application of the present invention. Summary of the Invention

[0007] In view of the above-mentioned defects, the present invention provides a method for promoting deep defluorination of a composite defluoridating agent by using a chelating agent, which aims to improve the removal efficiency of the composite defluoridating agent for fluoride ions.

[0008] The technical solution is: a method for promoting deep fluorine removal of a composite defluoridating agent by utilizing a chelating agent, wherein the chelating agent is compounded into the composite defluoridating agent to form a composite defluoridating agent, wherein the chelating agent is EDTA or / and an EDTA derivative, and the mass ratio of the composite defluoridating agent: chelating agent is 10-1:1-10.

[0009] Furthermore, the mass ratio of the composite defluoridating agent to the complexing agent is 3-1:1-3.

[0010] Further, the complex fluorine removal agent: complexing agent mass ratio is 2-1:1-2.

[0011] Further, the complex fluorine removal agent: complexing agent mass ratio is 1:1.

[0012] Further, the complex fluorine removal agent is composed of 20-40wt% of crystalline aluminum chloride, 15-35wt% of lanthanum nitrate, 10-20wt% of magnesium oxide, and the balance of water.

[0013] Further, the complex fluorine removal agent is composed of 20-40wt% of crystalline aluminum chloride, 15-35wt% of lanthanum nitrate, 10-20wt% of magnesium oxide, and the balance of water.

[0014] Further, the complex fluorine removal agent is composed of 20-40wt% of crystalline aluminum chloride, 15-35wt% of lanthanum nitrate, 10-20wt% of magnesium oxide, and the balance of water.

[0015] The application also provides a treatment method of fluorine-containing wastewater.

[0016] The technical solution is: a treatment method of fluorine-containing wastewater, which applies the above-mentioned complex fluorine removal agent to the treatment of fluorine-containing wastewater.

[0017] Further, the complex fluorine removal agent is composed of 20-40wt% of crystalline aluminum chloride, 15-35wt% of lanthanum nitrate, 10-20wt% of magnesium oxide, and the balance of water.

[0018] Compared with the prior art, the application has the beneficial effects that:

[0019] The application significantly improves the removal efficiency of the complex fluorine removal agent on fluorine ions by adding the complex, and effectively prevents the secondary pollution problem caused by excessive addition of the fluorine removal agent.

[0020] The complex fluorine removal agent formed by the application can also be used in combination with the lime method when applied to the treatment of fluorine-containing wastewater, further reducing the fluorine content in the wastewater. DETAILED DESCRIPTION

[0021] As used herein the terms "includes", "including", "has", "having", "comprises" and "comprising", or any other variation thereof, will cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0022] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having" and "including" or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements, but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0023] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0024] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Those skilled in the art will appreciate that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention. In the examples, where specific conditions are not specified, conventional conditions or manufacturer-recommended conditions were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0026] In these examples, parts and percentages are by mass unless otherwise indicated.

[0027] "Parts by mass" refers to the basic unit of measurement used to express the mass ratio of multiple components. One part can represent any unit of mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, this means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, we could say that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number representing a multiplication factor). It's important to note that, unlike parts by mass, the sum of the mass of all components is not limited to 100 parts.

[0028] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0029] In the present invention, crystalline aluminum chloride, lanthanum nitrate, magnesium oxide, EDTA, EDTA-2Na and composite metal aluminum salt defluoridating agent are all purchased from the market.

[0030] In the application, the proportion of each substance in the self-made composite fluoride removal agent is: 30wt% of crystalline aluminum chloride, 25wt% of lanthanum nitrate, 15wt% of magnesium oxide, and the balance is water. The self-made composite fluoride removal agent is referred to as self-prepared fluoride removal agent.

[0031] In the application, the proportion of each substance in the market-purchased fluoride removal agent (referred to as market-purchased fluoride removal agent) is: 60wt% of polyaluminum chloride, 3wt% of magnesium chloride, 13wt% of polyaluminum ferric chloride, and the balance is polyacrylamide. The market-purchased fluoride removal agent is a composite fluoride removal agent.

[0032] Example 1

[0033] A preparation method of a composite fluoride removal agent, comprising the following steps:

[0034] S1, taking 30g of the self-made composite fluoride removal agent and 10g of EDTA-2Na.

[0035] S2, uniformly mixing the self-made composite fluoride removal agent and EDTA-2Na to form a first composite fluoride removal agent.

[0036] Example 2

[0037] A preparation method of a composite fluoride removal agent, comprising the following steps:

[0038] S1, taking 20g of the self-made composite fluoride removal agent and 20g of EDTA-2Na.

[0039] S2, uniformly mixing the self-made composite fluoride removal agent and EDTA-2Na to form a second composite fluoride removal agent.

[0040] Example 3

[0041] A preparation method of a composite fluoride removal agent, comprising the following steps:

[0042] S1, taking 10g of the self-made composite fluoride removal agent and 30g of EDTA-2Na.

[0043] S2, uniformly mixing the self-made composite fluoride removal agent and EDTA-2Na to form a third composite fluoride removal agent.

[0044] Example 4

[0045] A preparation method of a composite fluoride removal agent, comprising the following steps:

[0046] S1, taking 30g of the market-purchased fluoride removal agent and 10g of EDTA-2Na.

[0047] S2, uniformly mixing the market-purchased fluoride removal agent and EDTA-2Na to form a fourth composite fluoride removal agent.

[0048] Example 5

[0049] A method for preparing a compound defluoridating agent comprises the following steps:

[0050] S1, take 20g of commercially available defluoridant and 20g of EDTA-2Na.

[0051] S2. Evenly mix the commercially available defluoridant with EDTA-2Na to form a fifth compound defluoridant.

[0052] Example 6

[0053] A method for preparing a compound defluoridating agent comprises the following steps:

[0054] S1, take 10g of commercially available defluoridant and 30g of EDTA-2Na.

[0055] S2. Evenly mix the commercially available defluoridant with EDTA-2Na to form a sixth compound defluoridant.

[0056] Example 7

[0057] S1, take 30g of homemade composite defluoridant and 10g of EDTA.

[0058] S2. Evenly mix the homemade composite defluoridant with EDTA to form the seventh composite defluoridant.

[0059] Example 8

[0060] S1, take 20g of homemade composite defluoridant and 20g of EDTA.

[0061] S2. Evenly mix the homemade composite defluoridant with EDTA to form an eighth composite defluoridant.

[0062] Example 9

[0063] S1, take 10g of homemade composite defluoridant and 30g of EDTA.

[0064] S2. Evenly mix the homemade composite defluoridant with EDTA to form a ninth composite defluoridant.

[0065] Example 10

[0066] S1, take 30g of commercially available defluoridant and 10g of EDTA.

[0067] S2. Evenly mix the commercially available defluoridant and EDTA to form a tenth compound defluoridant.

[0068] Example 11

[0069] S1, take 20g of commercially available defluoridant and 20g of EDTA.

[0070] S2. Evenly mix the commercially available defluoridant and EDTA to form an eleventh compound defluoridant.

[0071] Example 12

[0072] S1, take 10g of commercially available defluoridant and 30g of EDTA.

[0073] S2. Evenly mix the commercially available defluoridant with EDTA to form a twelfth compound defluoridant.

[0074] Example 13

[0075] The substances and dosages listed in Table 1 were added to the raw water to conduct a fluoride ion removal effect test. The results are shown in Table 1 below.

[0076] In the removal effect test, the reaction temperature was 35±1°C, the reaction time was 20 min, and the fluoride ion concentration in the raw water was 25 mg / L.

[0077] Table 1 Fluoride removal effect test of 25mg / L raw water

[0078]

[0079]

[0080] In Table 1, the dosage of 2g of the compound defluoridant group means: in the first compound defluoridant, the self-prepared defluoridant is 1.5g and the EDTA-2Na is 0.5g; in the second compound defluoridant, the self-prepared defluoridant is 1g and the EDTA-2Na is 1g; in the third compound defluoridant, the self-prepared defluoridant is 0.5g and the EDTA-2Na is 1.5g; and so on.

[0081] The results in Table 1 show that the fluoride ion concentration decreased significantly after the reaction with the addition of either the self-prepared or commercially available defluoridation agent, indicating that the self-prepared or commercially available defluoridation agent had a defluoridation effect. However, the fluoride ion concentration remained essentially unchanged after the addition of EDTA and its derivatives, and increasing the dosage did not increase their fluoride ion removal, indicating that EDTA and its derivatives themselves had no defluoridation effect. However, when EDTA and its derivatives were compounded with either the self-prepared or commercially available defluoridation agent, they effectively improved the fluoride ion removal efficiency of the self-prepared or commercially available defluoridation agent.

[0082] Example 8

[0083] The substances and dosages listed in Table 2 were added to the raw water to conduct a fluoride ion removal effect test. The results are shown in Table 2 below.

[0084] In the removal effect test, the reaction temperature was 35±1°C, the reaction time was 20 min, and the fluoride ion concentration in the raw water was 10 mg / L.

[0085] Table 2 Fluoride removal effect test of 10mg / L raw water

[0086]

[0087]

[0088]

[0089] As can be seen from Table 2, when the fluoride ion concentration in the raw water is low, EDTA and its derivatives can be compounded into self-prepared defluoridants or commercially purchased defluoridants to effectively improve the fluoride ion removal effect of the self-prepared composite defluoridants or commercially purchased defluoridants.

[0090] The present invention also provides a method for treating fluorine-containing wastewater, wherein the above-mentioned compound defluoridant is applied to treat the fluorine-containing wastewater. The method can be used in combination with a lime treatment process, and the amount of the compound defluoridant added is 0.1 to 10 g / L.

[0091] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0092] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the present application and to form different embodiments. For example, in the above description, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of the present application and should not be construed as an admission or any form of implication that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for promoting deep defluorination of a composite defluoridating agent by using a complexing agent, characterized in that: The method comprises compounding a complexing agent into a composite defluoridating agent to form a composite defluoridating agent, wherein the complexing agent is EDTA or / and an EDTA derivative, the mass ratio of the composite defluoridating agent to the complexing agent is 10-1:1-10, and the EDTA derivative is EDTA-2Na; The defluoridating agent is composed of: 20-40 wt % of crystalline aluminum chloride, 15-35 wt % of lanthanum nitrate, 10-20 wt % of magnesium oxide, and the balance is water; or The defluoridating agent comprises: 50-70 wt % of polyaluminium chloride, 1-5 wt % of magnesium chloride, 10-20 wt % of polyaluminium ferric chloride, and the balance is polyacrylamide.

2. The method for promoting deep defluorination of a composite defluoridating agent by using a complexing agent according to claim 1, characterized in that: The mass ratio of the composite defluoridating agent to the complexing agent is 3-1:1-3.

3. The method for promoting deep defluorination of a composite defluoridating agent by using a complexing agent according to claim 2, characterized in that: The mass ratio of the composite defluoridating agent to the complexing agent is 2-1:1-2.

4. The method for promoting deep defluorination of a composite defluoridating agent by using a complexing agent according to claim 3, characterized in that: The mass ratio of the composite defluoridating agent to the complexing agent is 1:

1.

5. The method for promoting deep defluorination of a composite defluoridating agent by using a complexing agent according to claim 1, characterized in that: The compounding is to mix the complexing agent and the composite defluoridating agent evenly.

6. A method for treating fluorine-containing wastewater, characterized in that: The method applies the compound defluoridating agent described in any one of claims 1 to 5 to the treatment of fluorine-containing wastewater.

7. The method for treating fluorine-containing wastewater according to claim 6, characterized in that: The dosage of the compound defluoridating agent is 0.1-10 g / L.

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