Multi-metal nano-composite fluorine removal agent and preparation method thereof

Abstract

The invention discloses a multi-metal nano composite fluorine removal agent and a preparation method thereof, the fluorine removal agent comprises the following components by mass: 20%-30% of an aluminum salt, 1%-3% of a calcium salt, 1%-5% of a magnesium salt, 1%-5% of a titanium salt, 1%-5% of a cerium salt, 0.1%-0.5% of an acid, and the balance of water. According to the fluorine removal agent, nano titanium powder and nano cerium powder are introduced to be subjected to ion exchange and complexation reaction with fluoride in wastewater to form a titanium cerium-fluorine internal coordination complex, and meanwhile, the stability of the fluorine removal agent can be improved by adding titanium salt, so that the fluorine removal agent is suitable for strong acid or strong alkaline wastewater. The fluorine removal agent can stably treat the fluorine concentration in wastewater from about 200 mg / L to 1.0 mg / L or below, achieves up-to-standard discharge, meanwhile, is efficient and stable in fluorine removal, small in dosage, low in liquid caustic soda consumption, small in sludge yield, simple in process and low in comprehensive treatment cost, and can be widely applied to actual engineering.

Description

Technical Field

[0001] The invention relates to a defluorinating agent, in particular to a multi-metal nano composite defluorinating agent and a preparation method thereof. Background Art

[0002] In recent years, with the booming development of key strategic emerging industries such as photovoltaics, new energy vehicles, and semiconductors, fluorine-containing industrial wastewater generated in their production processes has increasingly become one of the main sources of environmental fluoride pollution. In view of its potential environmental impact, local governments have successively introduced strict environmental protection policies, listing fluoride as a characteristic pollutant that must be strictly controlled in environmental supervision, and explicitly requiring that the fluoride concentration be reduced to a standard below 1.0-1.5 mg / L before wastewater discharge. Faced with the urgent requirement to improve the discharge standard of fluoride-containing wastewater, adding high-efficiency defluoridation agents to enhance the fluoride removal efficiency has become the core strategy for deep purification of fluoride-containing wastewater.

[0003] However, there are a series of technical bottlenecks that need to be solved in the current deep defluorination technology system. The preparation process of most high-efficiency defluorinating agents is complicated, making it difficult to achieve large-scale production; the amount of defluorinating agents used is large, resulting in high defluorination costs; the instability of defluorination efficiency and the cumbersomeness of the treatment process increase the complexity and time cost of the overall operation. For example, patent CN202111619924.6 discloses a liquid defluorinating agent for fluoride-containing wastewater, which is composed of polymerized aluminum, iron salts, modified lignin and coagulants. The defluorinating agent uses a variety of mechanisms to effectively remove low-concentration fluoride ions, but there are problems such as large dosage, complicated preparation process, unstable effluent and possible color, which limit its wide application. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a high-efficiency and low-cost multi-metal nanocomposite defluorinating agent; another purpose of the present invention is to provide a method for preparing the multi-metal nanocomposite defluorinating agent.

[0005] Technical solution: The multi-metal nanocomposite defluoridating agent described in the present invention includes aluminum salt, calcium salt, magnesium salt, titanium salt, cerium salt and acid; by mass, the aluminum salt is 20% to 30%, the calcium salt is 1% to 3%, the magnesium salt is 1% to 5%, the titanium salt is 1% to 5%, the cerium salt is 1% to 5%, the acid is 0.1% to 0.5%, and the rest is water; the titanium salt is at least one of titanium diboride and titanium borate; the cerium salt is at least one of cerium acetate and cerium nitrate.

[0006] Preferably, the aluminum salt is at least one of aluminum chloride, aluminum sulfate, polyaluminum chloride and polyaluminum sulfate.

[0007] Preferably, the calcium salt is at least one of calcium chloride and calcium carbonate.

[0008] Preferably, the magnesium salt is at least one of magnesium sulfate, magnesium chloride and magnesium carbonate.

[0009] Preferably, the acid is at least one of sulfate, hydrochloric acid, citric acid, and glacial acetic acid.

[0010] Preferably, the water is purified water.

[0011] Preferably, the multi-metal nanocomposite defluoridation agent also includes an active agent; by mass, the active agent is 2% to 5%. After adding the active agent, the flocculation effect of the subsequent defluoridation agent can be enhanced, the amount of PAM added during defluoridation can be reduced (at least 30% of PAM can be reduced), and the comprehensive cost can be reduced by more than 15%. The active ingredient is still mainly metal salt, the defluoridation effect will not change, but the defluoridation cost will be reduced by more than 15%.

[0012] Preferably, the active auxiliary agent is at least one of active sodium silicate and modified carboxymethyl cellulose.

[0013] Preferably, the active sodium silicate is activated by sodium silicate using hydrochloric acid; the specific activation method is to quickly adjust the pH value to 2.0-2.5 after the water glass is acidified to reach an activation degree of 1.2%-1.5%, and stir for 3-4 hours to obtain the active sodium silicate. This method can prolong the shelf life of the activated silicate, while the coagulant effect remains basically unchanged. It should be noted that the activated silicate is easy to gel at pH=6-8, and quickly reaches pH=2 when acid is added. The activated silicate has the longest shelf life, and the shelf life of the activated silicate with a silica concentration of 1.5% reaches 40d, and the shelf life of the activated silicate with a silica concentration of 2.0% is also nearly one month. And studies have shown that the coagulant effect is relatively stable.

[0014] Preferably, the modified carboxymethyl cellulose is prepared by modifying carboxymethyl cellulose by preparing 1% to 1.5% carboxymethyl cellulose, adding glacial acetic acid to make it account for 2% to 3%, and heating in a water bath for 3 to 4 hours to obtain the modified carboxymethyl cellulose.

[0015] The preparation method of the multi-metal nanocomposite defluorination agent of the present invention comprises the following steps:

[0016] (1) mixing aluminum salt and magnesium salt according to a certain proportion and dissolving them in water to obtain a mixed solution 1;

[0017] (2) melting the titanium salt at high temperature under concentrated sulfuric acid and hydrogen peroxide to obtain a mixed solution 2;

[0018] (3) dissolving the cerium salt in concentrated hydrochloric acid by ultrasound assistance, and obtaining a mixed solution 3 after the cerium salt is completely dissolved;

[0019] (4) The mixed solution 1, the mixed solution 2 and the mixed solution 3 are heated, stirred and mixed to obtain a multi-metal nanocomposite defluorination agent.

[0020] Preferably, in step (1), the aluminum salt and the magnesium salt are mixed in proportion and dissolved in water, and stirred until completely dissolved to obtain a mixed solution 1.

[0021] More preferably, the stirring temperature in step (1) is 60-80°C.

[0022] Further preferably, the stirring speed in step (1) is 100 to 400 r / min, and the stirring is carried out for 1 to 3 hours.

[0023] More preferably, step (1) further comprises a cooling step after stirring until completely dissolved; and even more preferably, the cooling step is for 1 to 3 hours.

[0024] Preferably, the high temperature melting temperature in step (2) is 1400-1800° C. Some nano titanium powders (such as titanium diboride) are compounds with high hardness and high melting point. Under certain conditions (such as hydrogen peroxide and sulfuric acid), titanium diboride can undergo a dissolution reaction.

[0025] Preferably, the melted titanium powder in step (2) is slowly cooled in air and water.

[0026] Preferably, the concentration of the mixed solution 3, i.e., the cerium salt dispersion, in step (3) is 0.1-1 mol / L, and the ultrasonic-assisted dissolution data include a medium ultrasonic intensity and an oscillation time of 0.5-4 h. Ultrasonic-assisted dissolution under concentrated hydrochloric acid conditions can effectively increase the dissolution rate of cerium salt.

[0027] Preferably, before the stirring and mixing in step (4), the pH of mixed solution 1, mixed solution 2, and mixed solution 3 are adjusted to 1.5-4 using an acid.

[0028] Preferably, in step (4), the mixing is carried out by mechanical heating, stirring and mixing.

[0029] Preferably, the temperature for heating, stirring and mixing in step (4) is 60 to 80°C.

[0030] Preferably, the preparation method of the multi-metal nanocomposite defluorinating agent further includes stirring the active auxiliary agent under acidic conditions for at least 5 hours to activate it, and stopping stirring when the solution appears light blue or light yellow, to obtain a mixed solution 4; adding the mixed solution 1, mixed solution 2, and mixed solution 3 of step (4) to the mixed solution 4, heating and stirring to mix, to obtain the multi-metal nanocomposite defluorinating agent.

[0031] More preferably, the volume ratio of the active agent, the acid and the aqueous solution is (1-2): (0.5-1.5): (8-25).

[0032] More preferably, the mass fraction of the mixed solution 4 is 0.5-20wt%.

[0033] Principle of the invention: The core of the present invention is to use aluminum salt as a matrix, and cooperate with magnesium, nano-titanium, and cerium elements to construct a multi-mechanism synergistic defluorination system. This system significantly improves the removal efficiency and stability of fluoride ions in wastewater through precisely designed chemical and physical processes. The main mechanism of action is as follows: aluminum salt is the main component, and other metal elements (calcium, magnesium, titanium, cerium) are coordinated to jointly remove fluoride ions in wastewater. First, based on aluminum salt, the Al3+ ions released during the hydrolysis process not only form a strong complex with fluoride ions (F-), but also form Al(OH)3(am) alum flower structures, implement ligand exchange, physical adsorption and sweeping and other multiple mechanisms, and efficiently capture and remove fluoride ions in water. Secondly, the addition of magnesium salt cleverly enhances the compactness of the internal structure of the defluoridator, greatly increases the specific surface area and the number of fluoride ion binding active sites, and significantly improves the adsorption efficiency. In addition, nano titanium powder and nano cerium powder are introduced. These two nano materials, with their extremely high surface activity, undergo rapid ion exchange and complexation reactions with fluorides in wastewater to form stable titanium cerium-fluorine internal coordination complexes, which effectively broaden the scope of application of the defluoridation agent, especially in strong acid or strong alkaline wastewater environments. Excellent performance. At the same time, the addition of nano titanium also enhances the overall stability of the defluoridation agent and extends its service life. The present invention can also cleverly combine the coordination of active additives to promote the rate of the defluorination reaction and generate a large amount of aluminum hydroxide colloid during the hydrolysis process. These colloidal particles have a huge surface area and excellent adsorption capacity. They can not only efficiently adsorb suspended matter, colloidal substances and organic matter in water, but also promote the formation of larger floccules, which provides great convenience for subsequent defluorination sedimentation and filtration treatment.

[0034] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0035] (1) High efficiency: The defluoridation agent can quickly and efficiently capture low-concentration fluoride ions, stabilizing the fluoride concentration in fluoride-containing wastewater from about 200 mg / L to below 1.0 mg / L. The maximum removal rate can reach more than 99.5%, achieving standard discharge of fluoride-containing wastewater. The defluoridation rate of commercially available defluoridation agents is generally only 50% to 70%.

[0036] (2) Low cost: The dosage of the active ingredient of the defluoridation agent is ≤80mg / L. Compared with the common commercial defluoridation agents, the dosage is reduced by more than 30%, the overall cost is low, and there will be no problems such as small flocs being difficult to settle and reverse release of the agent. In particular, the addition of active additives can enhance the flocculation effect of the subsequent defluoridation agent, reduce the dosage of PAM during defluoridation (reduce at least 30% of PAM), and further reduce the overall cost by more than 15%.

[0037] (3) The defluorination agent has a wide range of applications: The introduced titanium salt nanopowder forms a stable titanium-fluorine complex with fluoride ions, which enhances the stability of the defluorination agent and effectively broadens the application range of the defluorination agent, especially in strong acid or strong alkaline wastewater environments, showing excellent performance.

[0038] (4) Environmentally friendly: The preparation and use of defluorination agents adopt environmentally friendly materials and technologies, will not produce secondary pollutants, will not cause pipeline clogging and scaling, and will reduce the impact on the environment. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below in conjunction with embodiments.

[0040] Example 1

[0041] Raw material composition (by mass): 5% polyaluminium chloride, 17% aluminium sulfate, 1% calcium carbonate, 1% magnesium carbonate, 2% titanium borate, 1% cerium acetate, 0.2% hydrochloric acid, and the remainder water.

[0042] Preparation method:

[0043] Step 1: After mixing polyaluminium chloride, aluminium sulfate, calcium carbonate and magnesium carbonate in proportion, dissolving them in water, heating and stirring them in a water bath at 80° C. for 2 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0044] Step 2: melting titanium borate under concentrated sulfuric acid and hydrogen peroxide at a high temperature of 1400° C. to obtain a mixed solution 2;

[0045] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 3 hours to obtain a mixed solution 3 after complete dissolution;

[0046] Step 4: Mix solution 1, solution 2, and solution 3 and further stir and mix by mechanically heating to 60° C. until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0047] The above defluoridation agent was applied to a photovoltaic wastewater in Jiangsu, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, and each two portions were used as parallel tests. The fluoride concentration of the inlet water was measured to be 199.50 mg / L and the pH was 7.5. This raw water was not added with defluoridation agent as a control test. The new defluoridant and the commercially available defluoridant were added in different solution volume ratios, and the pH was adjusted to neutral (6.0-6.5) with 30% liquid alkali, and the reaction was fully stirred for 10 minutes; 1 mL of 1 / 1000 anionic PAM was added, and the stirring was rapidly stirred for 30 seconds, and the stirring was stopped when large flocs were produced; the mixture was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water body is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.67 mg / L. Compared with the commercially available defluoridant, the new defluoridant formula and preparation method were used, and under the same application conditions, the dosage of the new defluoridant was significantly reduced, and the defluoridation effect was significant.

[0048]

[0049]

[0050] Example 2

[0051] Raw material composition (by mass): 10% polyaluminium chloride, 18% polyaluminium sulfate, 3% calcium chloride, 3% magnesium chloride, 3% titanium diboride, 3% cerium acetate, 0.3% sulfuric acid, and the remainder is purified water.

[0052] Preparation method:

[0053] Step 1: Mix polyaluminium chloride, polyaluminium sulfate, calcium chloride and magnesium chloride in proportion, dissolve in pure water, heat and stir in a water bath at 70°C for 3 hours until the solid is completely dissolved, to obtain a mixed solution 1;

[0054] Step 2: melting titanium diboride at 1600° C. under concentrated sulfuric acid and hydrogen peroxide conditions to obtain a mixed solution 2;

[0055] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 4 hours to obtain a mixed solution 3 after complete dissolution;

[0056] Step 4: Mix solution 1, solution 2, and solution 3 and further stir and mix by mechanically heating to 80° C. until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0057] The above defluoridation agent was applied to a certain acidic fluoride-containing wastewater in Jiangsu, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, of which two portions were used as parallel tests. The influent fluoride concentration was determined to be 220.3 mg / L and the pH was 2.8. This raw water was not added with defluoridation agent as a control test. The new defluoridation agent and commercial defluoridation agent were added according to different solution volume ratios, and the pH was adjusted to neutral (6.0-6.5) with 30% liquid alkali, and the reaction was stirred for 10 minutes; 1mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.89 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0058]

[0059] Example 3

[0060] Raw material composition (by mass): 2% aluminum chloride, 20% polyaluminum sulfate, 1% calcium carbonate, 5% magnesium chloride, 5% titanium borate, 2% cerium nitrate, 0.1% glacial acetic acid, and the remainder is purified water.

[0061] Preparation method:

[0062] Step 1: Aluminum chloride, polyaluminum sulfate, calcium carbonate, and magnesium chloride are mixed in proportion, dissolved in pure water, heated in a water bath at 80° C. and stirred for 2 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0063] Step 2: melting titanium borate under concentrated sulfuric acid and hydrogen peroxide at a high temperature of 1400° C. to obtain a mixed solution 2;

[0064] Step 3: cerium nitrate is subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 4 hours to obtain a mixed solution 3 after complete dissolution;

[0065] Step 4: Mix solution 1, solution 2, and solution 3 and further stir and mix by mechanically heating to 80° C. until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0066] The above defluoridation agent was applied to fluorine-containing wastewater from a coal chemical industry, and was compared with commercial defluoridation agents whose main components were aluminum salts and calcium salts. Several 1L portions of fluorine-containing wastewater raw water were prepared, of which two portions were used as parallel tests. After pretreatment, the influent fluoride concentration was measured to be 200.64 mg / L and the pH was 7.8. This raw water was not added with defluoridation agent as a control test. Defluoridation agent was added according to different solution volume ratios, and 30% liquid alkali was used to adjust the pH to neutral (6.0-6.5), and the reaction was stirred for 10 minutes; 1 mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.66 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0067]

[0068] Example 4

[0069] This embodiment provides an active auxiliary agent.

[0070] After adding acid to sodium silicate in water glass to reach a suitable activation degree of 1.2%, the pH value is quickly adjusted to 2.0 and stirred for 3 to 4 hours to obtain active sodium silicate, which is then used in a defluoridation agent.

[0071] Example 5

[0072] This embodiment provides an active auxiliary agent.

[0073] After adding acid to sodium silicate in water glass to reach a suitable activation degree of 1.5%, the pH value is quickly adjusted to 2.3 and stirred for 3 to 4 hours to obtain active sodium silicate, which is then used in a defluoridation agent.

[0074] Example 6

[0075] This embodiment provides an active auxiliary agent.

[0076] After adding acid to sodium silicate in water glass to reach a suitable activation degree of 1.5%, the pH value is quickly adjusted to 2.5 and stirred for 3 to 4 hours to obtain active sodium silicate, which is then used in a defluoridation agent.

[0077]

[0078] Example 7

[0079] Raw material composition (by mass): 5% polyaluminium chloride, 17% aluminium sulfate, 1% calcium carbonate, 1% magnesium carbonate, 2% titanium borate, 1% cerium acetate, 2% active sodium silicate of Example 4, 0.2% hydrochloric acid, and the remainder purified water.

[0080] Preparation method:

[0081] Step 1: After mixing polyaluminium chloride, aluminium sulfate, calcium carbonate and magnesium carbonate in proportion, dissolving in pure water, heating in a water bath at 80° C. and stirring for 2 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0082] Step 2: melting titanium borate under concentrated sulfuric acid and hydrogen peroxide at a high temperature of 1400° C. to obtain a mixed solution 2;

[0083] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 3 hours to obtain a mixed solution 3 after complete dissolution;

[0084] Step 4: Activate the active agent under acidic conditions by slowly stirring for at least 5 hours, and stop stirring when the solution turns light blue to obtain a mixed solution 4;

[0085] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mechanically heat to 60° C. and stir and mix until the solutions are evenly mixed to obtain a multi-metal nanocomposite defluoridating agent.

[0086] The above defluoridation agent was applied to a photovoltaic wastewater in Jiangsu, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, and each two portions were used as parallel tests. The fluoride concentration of the inlet water was measured to be 199.50 mg / L and the pH was 7.5. This raw water was not added with defluoridation agent as a control test. The new defluoridant and commercially available defluoridant were added in different solution volume ratios, 30% liquid alkali was used to adjust the pH to neutral (6.0-6.5), and the reaction was stirred for 10 minutes; 0.7 mL of 1 / 1000 anionic PAM was added, and the stirring was rapidly stirred for 30 seconds, and the stirring was stopped when large flocs were produced; the mixture was allowed to stand for 20 minutes until all the produced flocs were settled; the supernatant was taken to detect the fluoride content (if the water body is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.67 mg / L. Compared with the commercially available defluoridant, the dosage of the new defluoridant was significantly reduced by adopting the new defluoridant formula and preparation method under the same application conditions, and the defluoridation effect was significant.

[0087]

[0088]

[0089] Example 8

[0090] Raw material composition (by mass): 10% polyaluminium chloride, 18% polyaluminium sulfate, 3% calcium chloride, 3% magnesium chloride, 3% titanium diboride, 3% cerium acetate, 3% modified carboxymethyl cellulose, 0.3% sulfuric acid, and the remainder water.

[0091] Preparation method:

[0092] Step 1: Mix polyaluminium chloride, polyaluminium sulfate, calcium chloride and magnesium chloride in proportion, dissolve in water, heat and stir in a water bath at 70° C. for 3 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0093] Step 2: melting titanium diboride at 1600° C. under concentrated sulfuric acid and hydrogen peroxide conditions to obtain a mixed solution 2;

[0094] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 4 hours to obtain a mixed solution 3 after complete dissolution;

[0095] Step 4: slowly stirring the modified carboxymethyl cellulose under acidic conditions for 5 hours to activate it, and stopping stirring when the solution turns light yellow to obtain a mixed solution 4;

[0096] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mechanically heat to 80° C. and stir and mix until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0097] The above defluoridation agent was applied to a certain acidic fluoride-containing wastewater in Jiangsu, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, of which two portions were used as parallel tests. The influent fluoride concentration was measured to be 220.30 mg / L and the pH was 2.8. This raw water was not added with defluoridation agent as a control test. The new defluoridation agent and commercial defluoridation agent were added according to different solution volume ratios, and the pH was adjusted to neutral (6.0-6.5) with 30% liquid alkali, and the reaction was stirred for 10 minutes; 0.8 mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.89 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0098]

[0099]

[0100] Example 9

[0101] Raw material composition (by mass): 2% aluminum chloride, 20% polyaluminum sulfate, 1% calcium chloride, 5% magnesium chloride, 5% titanium borate, 2% cerium nitrate, 5% active sodium silicate of Example 5, 0.1% glacial acetic acid, and the remainder is purified water.

[0102] Preparation method:

[0103] Step 1: Aluminum chloride, polyaluminum sulfate, calcium chloride, and magnesium chloride are mixed in proportion, dissolved in pure water, heated in a water bath at 80° C. and stirred for 2 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0104] Step 2: melting titanium borate under concentrated sulfuric acid and hydrogen peroxide at a high temperature of 1400° C. to obtain a mixed solution 2;

[0105] Step 3: cerium nitrate is subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 4 hours to obtain a mixed solution 3 after complete dissolution;

[0106] Step 4: Activate the active sodium silicate under acidic conditions by slowly stirring for at least 5 hours, and stop stirring when the solution turns light blue to obtain a mixed solution 4;

[0107] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mix them by mechanical heating and stirring at 80° C. until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0108] The above defluoridation agent was applied to fluorine-containing wastewater from a coal chemical industry, and was compared with commercial defluoridation agents whose main components were aluminum salts and calcium salts. Several 1L portions of fluorine-containing wastewater raw water were prepared, of which two portions were used as parallel tests. After pretreatment, the influent fluoride concentration was measured to be 200.64 mg / L and the pH was 7.8. This raw water was not added with defluoridation agent as a control test. Defluoridation agent was added according to different solution volume ratios, and 30% liquid alkali was used to adjust the pH to neutral (6.0-6.5), and the reaction was stirred for 10 minutes; 0.5 mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.66 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0109]

[0110] Example 10

[0111] Raw material composition (by mass): 2% polyaluminium chloride, 27% polyaluminium sulfate, 1% calcium chloride, 5% magnesium chloride, 5% titanium diboride, 5% cerium nitrate, 5% modified carboxymethyl cellulose, 0.1% sulfuric acid, 0.2% glacial acetic acid, and the remainder is purified water.

[0112] Preparation method:

[0113] Step 1: Mix polyaluminium chloride, polyaluminium sulfate, calcium chloride and magnesium chloride in proportion, dissolve in pure water, heat and stir in a water bath at 70° C. for 2 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0114] Step 2: melting titanium diboride at 1800° C. under concentrated sulfuric acid and hydrogen peroxide conditions to obtain a mixed solution 2;

[0115] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 2 hours to obtain a mixed solution 3 after complete dissolution;

[0116] Step 4: Activate the modified carboxymethyl cellulose under acidic conditions by slowly stirring for at least 4 hours, and stop stirring when the solution turns light yellow to obtain a mixed solution 4;

[0117] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mix by mechanical heating and stirring until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0118] The above defluoridation agent was applied to fluoride-containing wastewater from a chemical industry in Henan Province, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, of which two portions were used as parallel tests. The fluoride concentration was determined to be 167.40 mg / L and the pH was 9.80. This raw water was not added with defluoridation agent as a control test. Defluoridation agent was added according to different solution volume ratios, and 30% liquid alkali was used to adjust the pH to neutral (6.0-6.5), and the reaction was stirred for 10 minutes; 0.6 mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.52 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0119]

[0120] Embodiment 11

[0121] Raw material composition (by mass): 5% aluminum chloride, 20% polyaluminum sulfate, 5% calcium carbonate, 1% magnesium sulfate, 1% titanium borate, 5% cerium acetate, 3% active sodium silicate of Example 6, 0.1% sulfuric acid, 0.1% hydrochloric acid, 0.1% glacial acetic acid, and the remainder is purified water.

[0122] Preparation method:

[0123] Step 1: Aluminum chloride, polyaluminum sulfate, calcium carbonate, and magnesium sulfate are mixed in proportion, dissolved in pure water, heated in a water bath at 80° C. and stirred for 4 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0124] Step 2: melting titanium borate under concentrated sulfuric acid and hydrogen peroxide at a high temperature of 1700° C. to obtain a mixed solution 2;

[0125] Step 3: cerium acetate was subjected to ultrasonic treatment in concentrated hydrochloric acid at a medium intensity for 4 hours to obtain a mixed solution 3 after complete dissolution;

[0126] Step 4: slowly stirring the active sodium silicate under acidic conditions for 5 hours to activate it, and stopping stirring when the solution turns light blue to obtain a mixed solution 4;

[0127] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mix by mechanical heating and stirring until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0128] The above defluoridation agent was applied to fluoride-containing wastewater from a quartz sand in Jiangsu, and was compared with commercial defluoridation agents whose main components were aluminum salt and calcium salt. Several 1L portions of fluoride-containing wastewater raw water were prepared, of which two portions were used as parallel tests. The fluoride concentration was determined to be 189.35 mg / L and the pH was 6.7. This raw water was not added with defluoridation agent as a control test. Defluoridation agent was added according to different solution volume ratios, and 30% liquid alkali was used to adjust the pH to neutral (6.0-6.5), and the reaction was stirred for 10 minutes; 0.6 mL of 1 / 1000 anionic PAM was added, and the stirring was stopped when large flocs were produced; it was allowed to stand for 20 minutes until all the flocs were settled; the supernatant was taken to detect the fluoride content (if the water is turbid, filtration can be selected), and the water fluoride concentration was detected to be 0.74 mg / L. Compared with commercially available defluorinators, the new defluorinator formula and preparation method can significantly reduce the dosage of the new defluorinator under the same application conditions, and the defluorination effect is significant.

[0129]

[0130] Example 12

[0131] Raw material composition (by mass): polyaluminium chloride 22%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 2%, cerium acetate 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is the same as in Example 1, except that the aluminium salt is polyaluminium chloride only.

[0132] Embodiment 13

[0133] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 1%, titanium diboride 1%, cerium nitrate 0.5%, cerium acetate 0.5%, hydrochloric acid 0.2%, the remainder being water. The preparation method is the same as in Example 1, except that titanium borate and titanium diboride are used as the titanium salt, and cerium nitrate and cerium acetate are used as the cerium salt.

[0134] Embodiment 14

[0135] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 2%, cerium nitrate 0.5%, cerium acetate 0.5%, hydrochloric acid 0.2%, the remainder being water. The preparation method is the same as in Example 1, except that the cerium salt is cerium nitrate and cerium acetate at the same time.

[0136] Embodiment 15

[0137] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 1%, titanium diboride 1%, cerium acetate 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is the same as in Example 1, except that titanium borate and titanium diboride are used as the titanium salt at the same time.

[0138] The defluorination agents of Examples 12-15 were applied under the same conditions as Example 1, and the following results were obtained.

[0139]

[0140] Comparative Examples 1 to 7 show the effects of different titanium salt, cerium salt or titanium salt, cerium salt content ranges on the defluorination effect and dosage.

[0141] Comparative Example 1

[0142] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium dioxide 2%, cerium oxide 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as that of Example 1, except that the titanium salt is replaced by titanium dioxide and the cerium salt is replaced by cerium oxide.

[0143] Comparative Example 2

[0144] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium dioxide 2%, cerium acetate 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that the titanium salt is replaced by titanium dioxide.

[0145] Comparative Example 3

[0146] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 2%, cerium oxide 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that the cerium salt is replaced by cerium oxide.

[0147] Comparative Example 4

[0148] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 2%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that no cerium salt is added.

[0149] Comparative Example 5

[0150] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, cerium nitrate 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that titanium salt is not added.

[0151] Comparative Example 6

[0152] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 10%, cerium acetate 1%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that the titanium salt content is different.

[0153] Comparative Example 7

[0154] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 2%, cerium acetate 10%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that the cerium salt content is different.

[0155] Comparative Example 8

[0156] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium borate 10%, cerium acetate 10%, hydrochloric acid 0.2%, the remainder being water. The preparation method is basically the same as in Example 1, except that the contents of titanium salt and cerium salt are different.

[0157] Comparative Example 9

[0158] Raw material composition (by mass): polyaluminium chloride 5%, aluminium sulfate 17%, calcium carbonate 1%, magnesium carbonate 1%, titanium carbonate 2%, cerium hydroxide 1%, hydrochloric acid 0.2%, active sodium silicate of Example 4 2%, and the remainder water. The preparation method is basically the same as that of Example 7, except that the titanium salt is replaced by titanium carbonate and the cerium salt is replaced by cerium hydroxide.

[0159] The defluorination agents of Comparative Examples 1 to 9 were compared with the novel defluorination agent of Example 1 of the present invention under the same conditions, and the following results were obtained: Among them, although the defluorination rates of Comparative Examples 6 to 8 were high, the costs were also high due to the large amounts of titanium salt and cerium salt used.

[0160]

[0161]

[0162] Comparative Examples 10 to 12: Effect of the absence of titanium salt and cerium salt on the defluorination effect and dosage

[0163] Comparative Example 10

[0164] Raw material composition (by mass): 30% polyaluminium chloride, 5% calcium carbonate, 1% magnesium sulfate, 0.1% sulfuric acid, and the remainder is purified water.

[0165] Preparation method: Mix polyaluminum chloride, polyaluminum sulfate, calcium carbonate and magnesium sulfate in proportion, dissolve in pure water, heat and stir in a water bath at 80°C for 4 hours, adjust the pH of the solution with sulfuric acid until the solid is completely dissolved, and obtain a multi-metal composite defluoridation agent.

[0166] Comparative Example 11

[0167] Raw material composition (by mass): 30% polyaluminium sulfate, 5% calcium chloride, 5% magnesium chloride, 0.1% sulfuric acid, and the remainder purified water.

[0168] Preparation method: Mix polyaluminum sulfate, calcium chloride and magnesium chloride in proportion, dissolve in pure water, heat and stir in a water bath at 80°C for 4 hours, adjust the pH of the solution with sulfuric acid until the solid is completely dissolved, and a multi-metal composite defluoridant can be obtained.

[0169] Comparative Example 12

[0170] Raw material composition (by mass): 10% polyaluminium chloride, 20% calcium chloride, 20% magnesium chloride, and the remainder is purified water.

[0171] Preparation method: Mix polyaluminum chloride, calcium chloride and magnesium chloride in proportion, dissolve in pure water, heat and stir in a water bath at 80°C for 4 hours until the solid is completely dissolved, and a multi-metal nanocomposite defluoridant can be obtained.

[0172] The defluorinating agents of Comparative Examples 10 to 12 were compared with the novel defluorinating agent of Example 1 of the present invention under the same conditions, and the following results were obtained.

[0173]

[0174] Comparative Examples 13-14 Effects of different preparation methods on defluorination effect and dosage

[0175] Comparative Example 13

[0176] Raw material composition (by mass): aluminum chloride 5%, polyaluminum sulfate 20%, calcium carbonate 5%, magnesium sulfate 1%, titanium borate 1%, cerium acetate 5%, sulfuric acid 0.1%, hydrochloric acid 0.1%, glacial acetic acid 0.1%, and the rest is purified water.

[0177] Preparation method:

[0178] Step 1: Aluminum chloride, polyaluminum sulfate, calcium carbonate, and magnesium sulfate are mixed in proportion, dissolved in pure water, heated in a water bath at 80° C. and stirred for 4 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0179] Step 2: dissolving titanium borate in concentrated sulfuric acid at a low temperature (60° C.) to obtain a mixed solution 2;

[0180] Step 3: dissolving cerium acetate under hydrochloric acid conditions with slight heat (60° C.) to obtain a mixed solution 3;

[0181] Step 4: Mix solution 1, solution 2, and solution 3 and mix them by mechanical heating and stirring until the solutions are evenly mixed to obtain a multi-metal nanocomposite defluoridating agent.

[0182] Comparative Example 14

[0183] Raw material composition (by mass): 5% aluminum chloride, 20% polyaluminum sulfate, 5% calcium carbonate, 1% magnesium sulfate, 1% titanium borate, 5% cerium acetate, 3% active sodium silicate of Example 6, 0.1% sulfuric acid, 0.1% hydrochloric acid, 0.1% glacial acetic acid, and the remainder is purified water.

[0184] Preparation method:

[0185] Step 1: Aluminum chloride, polyaluminum sulfate, calcium carbonate, and magnesium sulfate are mixed in proportion, dissolved in pure water, heated in a water bath at 80° C. and stirred for 4 h until the solid is completely dissolved, to obtain a mixed solution 1;

[0186] Step 2: heating titanium borate to 80° C. in water and stirring to dissolve the mixture to obtain a mixed solution 2;

[0187] Step 3: heating cerium acetate in water to 80° C. and stirring to dissolve the cerium acetate to obtain a mixed solution 3;

[0188] Step 4: slowly stirring the active sodium silicate under acidic conditions for 5 hours to activate it, and stopping stirring when the solution turns light blue to obtain a mixed solution 4;

[0189] Step 5: Slowly add solution 1, solution 2, and solution 3 to solution 4, and mix by mechanical heating and stirring until the solutions are evenly mixed, thereby obtaining a multi-metal nanocomposite defluoridating agent.

[0190] The defluorinating agents of Comparative Examples 13 to 14 were compared with the novel defluorinating agent of Example 1 of the present invention under the same conditions, and the following results were obtained.

[0191]

Claims

1. A multi-metal nanocomposite defluorination agent, characterized in that: It includes aluminum salt, calcium salt, magnesium salt, titanium salt, cerium salt and acid; by mass, the aluminum salt is 20% to 30%, the calcium salt is 1% to 3%, the magnesium salt is 1% to 5%, the titanium salt is 1% to 5%, the cerium salt is 1% to 5%, the acid is 0.1% to 0.5%, and the rest is water; the titanium salt is at least one of titanium diboride and titanium borate; the cerium salt is at least one of cerium acetate and cerium nitrate.

2. The multi-metal nanocomposite defluorination agent according to claim 1, characterized in that: The aluminum salt is at least one of aluminum chloride, aluminum sulfate, polyaluminum chloride, and polyaluminum sulfate; the calcium salt is at least one of calcium chloride and calcium carbonate; and the magnesium salt is at least one of magnesium sulfate, magnesium chloride, and magnesium carbonate.

3. The multi-metal nanocomposite defluorination agent according to claim 1, characterized in that: The acid is at least one of sulfuric acid, hydrochloric acid, citric acid and glacial acetic acid.

4. The multi-metal nanocomposite defluorination agent according to claim 1, characterized in that: The invention also comprises an active auxiliary agent, which accounts for 2% to 5% by mass.

5. The multi-metal nanocomposite defluorination agent according to claim 4, characterized in that: The active auxiliary agent is at least one of active sodium silicate and modified carboxymethyl cellulose.

6. A method for preparing the multi-metal nanocomposite defluorinating agent according to claim 1, characterized in that: The following steps are involved: (1) mixing aluminum salt, calcium salt and magnesium salt in proportion and dissolving them in water to obtain a mixed solution 1; (2) melting the titanium salt at high temperature under concentrated sulfuric acid and hydrogen peroxide to obtain a mixed solution 2; (3) dissolving the cerium salt in concentrated hydrochloric acid by ultrasound assistance, and obtaining a mixed solution 3 after the cerium salt is completely dissolved; (4) The mixed solution 1, the mixed solution 2 and the mixed solution 3 are heated, stirred and mixed to obtain a multi-metal nanocomposite defluorination agent.

7. The method for preparing the multi-metal nanocomposite defluorinating agent according to claim 6, characterized in that: The high temperature melting temperature in step (2) is 1400°C to 1800°C.

8. The method for preparing the multi-metal nanocomposite defluorinating agent according to claim 6, characterized in that: The concentration of the mixed solution 3, i.e., the cerium salt dispersion, in step (3) is 0.1-1 mol / L, and the ultrasonic-assisted dissolution data include a medium ultrasonic intensity and an oscillation time of 0.5-4 h.

9. The method for preparing the multi-metal nanocomposite defluorinating agent according to claim 6, characterized in that: Before the stirring and mixing in step (4), the pH of mixed solution 1, mixed solution 2, and mixed solution 3 is adjusted to 1.5 to 4.0 using an acid.

10. The method for preparing the multi-metal nanocomposite defluorinating agent according to claim 6, characterized in that: The method also includes stirring the active auxiliary agent under acidic conditions for at least 5 hours to activate it, and stopping stirring when the solution turns light blue or light yellow to obtain a mixed solution 4; adding the mixed solution 1, mixed solution 2, and mixed solution 3 of step (4) into the mixed solution 4, heating and stirring to mix, and obtaining a multi-metal nanocomposite defluorinating agent.

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