Method for treating fluorine-containing waste water

Abstract

The present application relates to wastewater treatment technical field, disclose a kind of fluorine-containing wastewater treatment method.A kind of fluorine-containing wastewater treatment method, it is characterized in that, the method includes using aluminum-containing adsorbent to carry out the adsorption of fluorine ion in fluorine-containing wastewater;Wherein, the aluminum-containing adsorbent is prepared by mixing pseudo-boehmite powder with forming aid, acid, water and optional Y-type molecular sieve, and sequentially forming, drying and optional calcining are carried out.The treatment method of the present application is simple and easy to operate, and has low operating cost, and has good treatment effect on fluorine ion in water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a treatment method of fluorine-containing wastewater. BACKGROUND

[0002] Fluorine is one of the important trace elements in human body, and the content of fluorine exceeding or being lower than the allowable range will cause great harm to human body. When the content of fluorine is too high, it will affect the metabolism of calcium and phosphorus in human body, and make the material metabolism and physiological function of human body disorder. The appropriate fluorine mass concentration of drinking water is 0.5-1.0 mg / L. In addition, in the industry, the wastewater discharged by the industries such as fluorite ore mining, metal smelting, aluminum processing, coke, glass, electronics, electroplating, chemical fertilizer and pesticide often contains high-concentration fluorides, causing serious environmental pollution. In order to protect the living environment of human beings and improve the quality of life of people, the defluorination research of fluorine-containing wastewater is an important task in the field of environmental protection and tailoring at home and abroad. The defluorination methods mainly include adsorption method, electrocoagulation method, reverse osmosis method, ion exchange method, membrane separation method, chemical precipitation method and coagulation sedimentation method. Among them, the electrocoagulation method and the reverse osmosis method have good removal effect, but the treatment cost is high; the ion exchange method, the membrane separation method and the precipitation method have relatively poor selectivity and limited removal capacity; the adsorption method has low research cost, good defluorination effect, high efficiency and simple operation, so it has been an important method for treating fluorine-containing wastewater.

[0003] At present, the commonly used adsorbents for removing negative ions in water include activated carbon, activated alumina, bone charcoal, zeolite and activated magnesium oxide. The activated alumina defluorination is the most widely used and most successful defluorination method at home and abroad, but the equipment investment is high, the safety of contacting strong acid and strong base is poor, and there are also defects such as poor mechanical strength. The application amount of bone charcoal is only second to that of activated alumina, and its defects are low adsorption capacity, large consumption of regenerant, long regeneration time, limited resources and high cost. Therefore, it is of great significance to develop an adsorption material suitable for fluorine-containing wastewater with low cost, easy regeneration, large adsorption capacity and high efficiency for the advanced treatment of fluorine-containing wastewater.

[0004] Pseudo-boehmite, also known as gelatinous boehmite or pseudo-gibbsite, has a chemical formula of AlOOH·nH2O (n=0.080-0.602), and is a kind of alumina hydrate with uncertain composition and incomplete crystallization. It is a non-toxic powder with low crystallinity and spatial network structure, which can be used as a catalyst carrier and can also react with nitric acid, hydrochloric acid and the like. There are many preparation methods of pseudo-boehmite, including alcohol aluminum hydrolysis method, carbonization method and aluminum salt neutralization method. The aluminum salt neutralization method, also known as aluminum salt and aluminate precipitation method, includes neutralization reaction of AlCl3 and NH4OH, and Al2(SO4)3 and NaAlO2 to generate pseudo-boehmite.

[0005] Among them, NaAlO2-Al2(SO4)3 method (also known as aluminum sulfate method) is a commonly used method for preparing pseudo-boehmite at present, both raw materials can provide aluminum source, corrosion is small, and it is liquid-liquid reaction, its process is simple, cost is low, and it can produce alumina carrier with large pore volume and specific surface area, and the preparation steps include neutralization, gelation, aging, washing, filtration, flash drying and the like. SUMMARY

[0006] The present application aims to overcome the problem of difficult treatment of fluorine-containing wastewater in the prior art, and provides a treatment method for fluorine-containing wastewater, which is simple to operate, low in operation cost, and has good treatment effect on fluorine ions in water.

[0007] In order to achieve the above-mentioned purpose, the present application provides a treatment method for fluorine-containing wastewater, which comprises using an aluminum-containing adsorbent to adsorb fluorine ions in the fluorine-containing wastewater; wherein the aluminum-containing adsorbent is prepared by mixing pseudo-boehmite powder, a molding aid, an acid, water and an optional Y-type molecular sieve, and then sequentially performing molding, drying and optional calcination.

[0008] Preferably, before using the aluminum-containing adsorbent to adsorb fluorine ions in the fluorine-containing wastewater, the pH of the fluorine-containing wastewater is adjusted to 6-8.

[0009] Preferably, the adsorption time is 30 min-1h.

[0010] Preferably, the molding aid is amaranth powder and / or cellulose.

[0011] Preferably, the acid is nitric acid.

[0012] Preferably, the Y-type molecular sieve is USY molecular sieve.

[0013] Preferably, the amount of the molding aid is 1-20 parts by weight, preferably 1-10 parts by weight, relative to 100 parts by weight of the pseudo-boehmite powder.

[0014] Preferably, the amount of the acid is 1-10 parts by weight, preferably 1-5 parts by weight, relative to 100 parts by weight of the pseudo-boehmite powder.

[0015] Preferably, the amount of the water is 50-500 parts by weight, preferably 80-250 parts by weight, relative to 100 parts by weight of the pseudo-boehmite powder.

[0016] Preferably, the amount of the Y-type molecular sieve is 0-500 parts by weight, relative to 100 parts by weight of the pseudo-boehmite powder.

[0017] Preferably, the calcination temperature is 400-700 DEG C, and the time is 1-4 hours.

[0018] Preferably, the temperature of the drying is 100-200℃, and the time is 2-4 hours.

[0019] Preferably, the forming is extrusion forming.

[0020] Preferably, the content of fluorine ions in the treated fluorine-containing wastewater is less than 1mg / L.

[0021] By the above technical solution, the treatment method of the present application can complete the treatment of fluorine-containing wastewater with simple operation, and achieve good effect on the removal of fluorine ions in water. The treatment method of the present application has simple process, low cost, simple equipment, convenient operation, high wastewater treatment efficiency, and can reduce the content of fluorine in wastewater to less than 1mg / L, which is particularly suitable for the advanced treatment of low fluorine-containing wastewater compared with other methods.

[0022] The aluminum-containing adsorbent prepared by the method of the present application has the characteristics of chemical stability, low cost, good adsorption effect and good regeneration performance.

[0023] According to the preferred embodiment of the present application, by using the aluminum-containing catalyst after calcination, the adsorption effect on fluorine ions in water can be significantly improved. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact values and ranges included between the endpoints are also intended to be explicitly included to this specification. Every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification includes every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification includes every narrower numerical range that falls within the broader numerical range, as if such narrower numerical ranges were all expressly written herein.

[0025] The present application provides a treatment method of fluorine-containing wastewater, which comprises using an aluminum-containing adsorbent to adsorb fluorine ions in fluorine-containing wastewater; wherein the aluminum-containing adsorbent is prepared by mixing pseudo-boehmite powder, a forming aid, acid, water and optional Y-type molecular sieve, and then sequentially performing forming, drying and optional calcination.

[0026] In the present application, a dry strip of carrier is prepared by using pseudo-boehmite powder, or the dry strip is calcined to obtain a carrier, which is used as an adsorbent for fluorine ions in fluorine-containing wastewater. By using the above dry strip and carrier, the removal efficiency of fluorine ions in water can be improved, and after use, it can still be restored to a high adsorption capacity by regeneration.

[0027] As the component of the above-mentioned aluminum-containing adsorbent, there is no particular limitation, and from the effect of adsorbing fluorine ions, preferably, the molding aid can be pearl millet powder and / or cellulose, the acid can be nitric acid, and the Y-type molecular sieve can be USY molecular sieve, and specifically, USY-5 molecular sieve can be used. Among them, the Y-type molecular sieve can be optionally added. The pseudoboehmite powder can be, for example, pseudoboehmite PB90, pseudoboehmite PB120, or SB powder synthesized by oneself.

[0028] In order to further improve the adsorption effect of the aluminum-containing adsorbent, preferably, the amount of the molding aid is 1-20 parts by weight, and preferably 1-10 parts by weight, relative to 100 parts by weight of the pseudoboehmite powder.

[0029] Preferably, the amount of the acid is 1-10 parts by weight, and preferably 1-5 parts by weight, relative to 100 parts by weight of the pseudoboehmite powder.

[0030] Preferably, the amount of the water is 50-500 parts by weight, and preferably 80-250 parts by weight, relative to 100 parts by weight of the pseudoboehmite powder.

[0031] Preferably, the amount of the Y-type molecular sieve is 0-500 parts by weight, relative to 100 parts by weight of the pseudoboehmite powder.

[0032] According to the present application, the above-mentioned components can be uniformly mixed, then molded, dried, and optionally calcined to obtain the aluminum-containing adsorbent of the present application. Among them, the conditions of mixing, molding, drying, and calcining can be any conditions that can obtain the aluminum-containing adsorbent, and the equipment used is not particularly limited.

[0033] The molding can be any molding that can obtain the dry rod of the desired size, and as the molding method, for example, extrusion molding can be used.

[0034] According to the preferred embodiment of the present application, the temperature of the drying can be 100-200°C, and the time can be 2-4 hours. Through the drying, the aluminum-containing adsorbent in the form of a dry rod can be obtained, which can be directly used for adsorption, or can be further calcined and then used for adsorption.

[0035] In order to further improve the adsorption performance of the aluminum-containing adsorbent, the above-mentioned calcination is preferably performed. That is, the aluminum-containing adsorbent in the form of a carrier is preferably used. According to the preferred embodiment of the present application, from the perspective of improving the adsorption performance of the aluminum-containing adsorbent, preferably, the temperature of the calcination is 400-700°C, and the time is 1-4 hours; more preferably, the temperature of the calcination is 550-650°C, and the time is 1-2 hours.

[0036] The treatment method of the present application can be widely used in various kinds of waste water containing fluorine ions, wherein the content of fluorine ions can be, for example, 1-50 mg / L or 1-20 mg / L, etc.

[0037] From the perspective of improving the adsorption effect of fluorine ions in cooperation with the aluminum-containing adsorbent of the present application, it is preferred that the pH of the waste water containing fluorine is adjusted to 6-8 before the adsorption of fluorine ions in the waste water containing fluorine is carried out by using the aluminum-containing adsorbent. By carrying out the adsorption under the above-mentioned pH condition, the performance of the aluminum-containing adsorbent can be better exerted.

[0038] In order to sufficiently carry out the process of adsorption, preferably, the time of the adsorption can be 30 min-1 h.

[0039] The process of the adsorption can be used by immersing the aluminum-containing adsorbent of the present application in the waste water containing fluorine, and in order to make the waste water containing fluorine and the aluminum-containing adsorbent fully contact, the two can also be appropriately mixed by stirring, etc.

[0040] Since the aluminum-containing adsorbent of the present application is shaped, after the adsorption is completed, it can be conveniently separated from the waste water containing fluorine, thereby facilitating the process of treatment. And by being appropriately shaped to the required size, the aluminum-containing adsorbent of the present application can cooperate with various different adsorption treatment scenarios.

[0041] In addition, the aluminum-containing adsorbent of the present application can also be conveniently regenerated after use, and still has a high adsorption effect after regeneration.

[0042] By using the treatment method of the present application, the content of fluorine ions in the waste water containing fluorine after treatment is lower than 1 mg / L, preferably 0.5 mg / L or less. The treatment method of the present application has a good treatment effect on waste water containing fluorine.

[0043] The present application will be described in detail below through examples.

[0044] Example 1

[0045] Three kinds of pseudo-boehmite powders (PB90, PB120, SB powder) of different series were respectively prepared into dry strips according to the ratio of 308 g: 6 g: 4 mL: 280 mL of pseudo-boehmite powder, sesbania powder, nitric acid, and purified water, and the dry strips were put into the waste water containing fluorine 5.09 g / mL (pH 6.2) to be treated, soaked for 1 h, and the fluorine ions in the waste water were removed by adsorption. After suction filtration, the fluorine content in the filtrate was analyzed, and the results are shown in Table 1 below.

[0046] Table 1

[0047] Example No. Dry stick Wastewater F content 1-1 PB90 dry stick 1 200ml 0.84 mg / L 1-2 PB120 dry stick 2 200ml 0.88 mg / L 1-3 SB powder dry stick 3 200ml 0.73 mg / L

[0048] Example 2

[0049] After different series of three kinds of pseudo-boehmite powders (PB90, PB120, SB powder) are respectively mixed with cellulose, nitric acid, clean water according to the ratio of 30.8g:3g:1.3mL:75mL to make dry strips, dried at 150℃ for 3 hours, and then calcined at 600℃ for 2 hours to prepare the carrier, 5g of the carrier is put into the waste water containing fluorine 5.09g / mL (pH is 6.2) to be treated, soaked for 1h, and the fluorine ion in the waste water is removed by adsorption, and then the fluorine content in the filtrate is analyzed after suction filtration, and the results are shown in Table 2.

[0050] Table 2

[0051] Example No. Carrier Wastewater F content 2-1 PB90 carrier 1 200ml 0.58 mg / L 2-2 PB120 carrier 2 200ml 0.46 mg / L 2-3 SB powder carrier 3 200ml 0.44 mg / L

[0052] It can be seen from the results of the above examples that the aluminum-containing adsorbent of the present application can obtain good fluorine ion adsorption effect.

[0053] Furthermore, it can be seen from the comparison between Example 1 and Example 2 that the fluorine ion adsorption effect can be further improved by calcining during the preparation of the aluminum-containing adsorbent.

[0054] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. A method for treating fluoride-containing wastewater, characterized in that, This method includes using aluminum-containing adsorbents to adsorb fluoride ions from fluoride-containing wastewater; The aluminum-containing adsorbent is prepared by mixing boehmite powder with molding aids, acid, water, and optionally a Y-type molecular sieve, followed by molding, drying, and calcination. The amount of the molding aid is 1-10 parts by weight relative to 100 parts by weight of the pseudoboehmite powder; The amount of acid used is 1-5 parts by weight relative to 100 parts by weight of the pseudoboehmite powder; The amount of water used is 80-250 parts by weight relative to 100 parts by weight of the pseudoboehmite powder. Before using aluminum-containing adsorbents to adsorb fluoride ions from fluoride-containing wastewater, the pH of the wastewater should be adjusted to 6-8. The adsorption time is 30 min to 1 h. The acid is nitric acid. The fluoride ion content in the treated fluoride-containing wastewater is less than 0.5 mg / L.

2. The processing method according to claim 1, wherein, The molding aid is guar gum powder and / or cellulose.

3. The processing method according to claim 1, wherein, The Y-type molecular sieve is a USY molecular sieve.

4. The processing method according to any one of claims 1-3, wherein, The amount of Y-type molecular sieve used is 0-500 parts by weight relative to 100 parts by weight of the pseudoboehmite powder.

5. The processing method according to any one of claims 1-3, wherein, The roasting temperature is 400-700℃, and the time is 1-4 hours.

6. The processing method according to any one of claims 1-3, wherein, The drying temperature is 100-200℃, and the time is 2-4 hours.

7. The processing method according to any one of claims 1-3, wherein, The forming process is extrusion forming.