A composite preparation for removing ammonia nitrogen from water, and its preparation method and application

Abstract

The present invention relates to a composite preparation for removing ammonia nitrogen from water, and a preparation method and application thereof. The composite preparation for removing ammonia nitrogen from water is mainly composed of the following components by mass fraction: 75% to 90% of modified carbon nitride, 8% to 20% of modified titanium dioxide, 2% to 5% of diatomaceous earth, and 1% to 2% of sodium sulfate. The composite preparation for removing ammonia nitrogen from water of the present invention can treat water with medium and low concentrations of ammonia nitrogen, has a simple preparation process, a high removal rate, and has a pH adjustment function. The composite preparation can be reused after simple treatment, and is suitable for removing ammonia nitrogen in aquaculture farms.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection and water treatment materials, and specifically relates to a composite preparation for removing ammonia nitrogen from water, and a preparation method and application thereof. Background Art

[0002] Ammonia nitrogen is one of the common pollutants in water, mainly from animal feces and food residues, pesticides and fertilizers in agricultural production, and industrial wastewater from meat processing, leather making, steel, petrochemicals, and pharmaceutical manufacturing. Excessive ammonia nitrogen content in water will disrupt the original ecological balance, causing eutrophication of water bodies, massive growth of algae, mass death of fish and shrimp, and deterioration of water quality.

[0003] Ammonia nitrogen in water is mainly in the form of free ammonia (NH 3 ) and ammonium ions (NH 4 + ) exist in two forms. When the pH of water rises, free ammonia (NH 3 ) content increases, causing great harm to aquatic animals and producing odor, increasing treatment costs.

[0004] The commonly used ammonia nitrogen treatment technologies can be divided into physical, chemical and biological removal technologies according to the removal principle. Physical removal technology mainly uses porous solid adsorbents to adsorb ammonia nitrogen in water on the surface of the material. It is widely used because of its low cost and simple operation. Patent application CN108940190A discloses a preparation method and application of modified zeolite, which has a better removal effect on ammonia nitrogen in sewage, but cannot reduce the pH of the water body; Patent application CN108479686A discloses Na 4 Ti 5 O 12 The preparation method and the application method in wastewater deammoniation are disclosed, but the titanate can only remove ammonium ions (NH 4 + ). Summary of the invention

[0005] In order to address the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a composite formulation for removing ammonia nitrogen from water and a preparation method thereof. The composite formulation for removing ammonia nitrogen from water can effectively remove ammonia nitrogen while reducing the pH of the water and improving the water quality.

[0006] Another object of the present invention is to provide an application of the above-mentioned composite preparation for removing ammonia nitrogen in water.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A composite preparation for removing ammonia nitrogen from water, mainly composed of the following components in mass fractions:

[0009]

[0010] Preferably, the composite preparation for removing ammonia nitrogen in water is composed of the following components in mass fractions:

[0011]

[0012] Preferably, the modified carbon nitride is prepared by the following steps:

[0013] (1) preparing a modifier solution with a concentration of 0.1 mol / L to 1 mol / L, wherein the modifier is a sodium salt or sodium hydroxide;

[0014] (2) weighing sodium bicarbonate and melamine in a molar ratio of 0.5:1 to 5:1, mixing them evenly, calcining them in a muffle furnace, washing them with water to neutrality after natural cooling, and drying them to obtain carbon nitride;

[0015] (3) Add carbon nitride to the modifier solution, stir for 8 to 12 hours, and after sufficient modification, filter, wash, and dry to obtain modified carbon nitride.

[0016] More preferably, the sodium salt is one of sodium chloride, sodium sulfate, sodium carbonate, sodium citrate, sodium dodecyl sulfate, and disodium ethylenediaminetetraacetate, and most preferably one of sodium dodecyl sulfate and disodium ethylenediaminetetraacetate.

[0017] More preferably, the initial calcination temperature is 20°C to 40°C, the heating time is 150min to 180min, the insulation temperature is 500°C to 600°C, and the insulation time is 240min to 360min.

[0018] More preferably, the solid-liquid ratio of carbon nitride to modifier solution is 1 g: (10-50) ml.

[0019] Preferably, the modified titanium dioxide is prepared by the following steps: weighing a certain amount of TiO 2 , soak in concentrated sulfuric acid with a mass fraction of 50% to 80% for 24 hours, and then soak the TiO 2 The mixture was kept at 400-800°C in a muffle furnace for 4-8 hours, cooled naturally, taken out and ground to obtain modified titanium dioxide.

[0020] The preparation method of the composite preparation for removing ammonia nitrogen in water comprises the following steps:

[0021] (1) Weigh the modified carbon nitride and diatomaceous earth in the required ratio and grind them in a ball mill for 30 minutes;

[0022] (2) Then, modified titanium dioxide and sodium sulfate were added in sequence, and grinding was continued for 30 minutes to obtain a composite preparation.

[0023] The composite preparation for removing ammonia nitrogen from water of the present invention is used in treating ammonia-containing water, and the application method comprises: placing the composite preparation in an amount of 0.05 g / L to 0.5 g / L in ammonia-containing water for a treatment time of 3 to 12 hours. 3 ) or ammonium ion (NH 4 + ) are adsorbed and removed, thereby reducing the ammonia nitrogen concentration in the water. At the same time, the modified titanium dioxide slowly releases protons, lowering the pH value of the water and effectively improving the water quality.

[0024] The ammonia-containing water body has an ammonia nitrogen concentration of 0.5 mg / L to 50 mg / L.

[0025] The modified titanium dioxide in the composite preparation used for treating water bodies can be recycled, and after recycling, it can be recycled according to the preparation method of the modified titanium dioxide.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] The composite preparation for removing ammonia nitrogen from water of the present invention can reduce the pH of water and improve water quality while efficiently removing ammonia nitrogen. Under static conditions, the ammonia nitrogen removal rate can reach 74.49%, and the pH of water can be reduced from 10.60 to 8.35.

[0028] The composite preparation for removing ammonia nitrogen in water bodies of the present invention has the advantages of simple preparation process, high removal rate, diverse functions and the like.

[0029] The composite preparation for removing ammonia nitrogen from water bodies of the present invention is used to treat ammonia-containing water bodies and has the characteristics of diverse functions, simple operation, green circulation, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is the ammonia nitrogen removal result of modified carbon nitride and modified 5A molecular sieve under different modifiers;

[0031] Figure 2 The graph is a graph showing the pH variation over time when the composite preparation for removing ammonia nitrogen from water according to the present invention is placed in an ammonia-containing water body. In the graph, ammonia nitrogen scavenger A refers to composite preparation A for removing ammonia nitrogen from water, and modified carbon nitride refers to carbon nitride modified by disodium ethylenediaminetetraacetate. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. The raw materials involved in the present invention can be purchased directly from the market. For process parameters not particularly noted, conventional techniques can be used.

[0033] Ammonia nitrogen concentration was determined using HJ 535-2009 "Determination of ammonia nitrogen in water - Nessler's reagent spectrophotometric method"

[0034] Removal rate η=(C 0 -C i ) / C 0 *100%

[0035] Where: C 0 is the ammonia nitrogen concentration of the original water (mg / L); C i It is the ammonia nitrogen concentration in the treated water (mg / L).

[0036] Comparative Example 1: Preparation of modified carbon nitride

[0037] Step 1: prepare 0.3 mol / L sodium chloride solution, disodium citrate solution, sodium dodecyl sulfate solution, disodium ethylenediaminetetraacetic acid solution, and sodium hydroxide solution respectively as modifier solutions;

[0038] Step 2: weigh sodium bicarbonate and melamine in a molar ratio of 0.5:1, mix well, transfer into a crucible, and place in a muffle furnace; the initial temperature is 30°C, the insulation temperature is 500°C, the heating time is 160min, and the insulation time is 240min; cool naturally to room temperature, wash with deionized water until neutral; place in an oven at 90°C for 12h;

[0039] Step 3: Add the dried powder into 5 groups of modifier solutions at a solid-liquid ratio of 1g:10mL respectively, stir magnetically at room temperature for 12h, filter, and dry in an oven at 90°C for 12h to obtain sodium chloride modified carbon nitride, disodium citrate modified carbon nitride, sodium dodecyl sulfonate modified carbon nitride, disodium ethylenediaminetetraacetic acid modified carbon nitride, and sodium hydroxide modified carbon nitride, respectively, for use.

[0040] The modified carbon nitride prepared above is used to treat ammonia-containing water, and the ammonia nitrogen content of the water is C 0 =5.5135mg / L.

[0041] Pipette 50 mL of ammonia-containing water into a 100 mL conical flask, add 0.1 g of the prepared modified carbon nitride, and after leaving for 12 hours, measure the ammonia nitrogen content C of the water. i , calculate the clearance rate η. The results are shown in Table 1:

[0042] Table 1 Ammonia nitrogen removal rate of modified carbon nitride in treating ammonia-containing water

[0043]

[0044]

[0045] It can be seen from the removal rates of various modified carbon nitrides in Table 1 that the ammonia nitrogen removal rate of carbon nitride can be effectively improved by modification with sodium dodecyl sulfate and disodium ethylenediaminetetraacetate.

[0046] Comparative Example 2: Preparation of modified 5A molecular sieve

[0047] Step 1: prepare 0.3 mol / L sodium chloride solution, disodium citrate solution, sodium dodecyl sulfate solution, disodium ethylenediaminetetraacetic acid solution, and sodium hydroxide solution respectively as modifier solutions.

[0048] Step 2: Wash the 5A molecular sieve with deionized water and dry it in an oven at 90°C for 12 hours.

[0049] Step 3: Add the dried powder to 5 groups of modifier solutions at a solid-liquid ratio of 1g:10mL, stir magnetically at room temperature for 12h, filter, and dry in an oven at 90°C for 12h to obtain sodium chloride modified 5A molecular sieve, disodium citrate modified 5A molecular sieve, sodium dodecyl sulfate modified 5A molecular sieve, disodium ethylenediaminetetraacetic acid modified 5A molecular sieve, and sodium hydroxide modified 5A molecular sieve, respectively, for use.

[0050] The modified 5A molecular sieve prepared above was used to treat ammonia-containing water, and the ammonia nitrogen content of the water was C 0 =5.5135mg / L.

[0051] Transfer 50 mL of ammonia-containing water into a 100 mL conical flask, add 0.1 g of the prepared modified 5A molecular sieve, and after leaving it for 12 hours, measure the ammonia nitrogen content of the water. i , calculate the clearance rate η. The results are shown in Table 2:

[0052] Table 2 Ammonia nitrogen removal rate of modified 5A molecular sieve in treating ammonia-containing water

[0053]

[0054] From the comparison of the removal rates of the modified 5A molecular sieves in Table 2 and the removal rates of the modified carbon nitrides in Table 1, it can be seen that the removal effect of the modified carbon nitride is better than that of the modified 5A molecular sieve. Figure 1 .

[0055] Comparative Example 3: Preparation of modified titanium dioxide

[0056] Step 1: Weigh a certain amount of analytical pure TiO 2 , soak in 75% concentrated sulfuric acid for 24 hours.

[0057] Step 2: Move into a muffle furnace, keep the temperature at 400°C for 4 hours, and grind into powder after natural cooling to obtain modified titanium dioxide.

[0058] Prepare 1L of 50mg / L ammonia water with an initial pH of 9.75, add 0.2g of modified titanium dioxide, and measure the pH change at a fixed time. The results are shown in Table 3:

[0059] Table 3 pH changes of water body neutralized by modified titanium dioxide

[0060]

[0061] It can be seen from Table 3 that when modified titanium dioxide is added to water, its proton release is a process, which gradually changes the pH of the water and improves the water quality.

[0062] As the main component of the ammonia-containing water filter column, the modified titanium dioxide can reduce the pH of the water after passing through it, and filter out impurities, with a highly efficient and significant treatment effect. At the same time, the modified titanium dioxide after use can be directly recovered, soaked in 75% concentrated sulfuric acid for 12 hours, roasted in a muffle furnace at 400°C for 4 hours, and cyclically measured. The results showed that when the initial pH of the water was 9.75, it was still able to reduce the pH of the water to about 8.5 after 12 hours. The effect did not decay after multiple cycles, with good repeatability and green economy.

[0063] Example 1

[0064] 1. Preparation of modified carbon nitride

[0065] Step 1: Prepare a 0.3 mol / L disodium ethylenediaminetetraacetic acid solution as a modifier solution;

[0066] Step 2: weigh sodium bicarbonate and melamine in a molar ratio of 0.5:1, mix well and transfer into a crucible, and place into a muffle furnace; the initial temperature is 30°C, the insulation temperature is 500°C, the heating time is 160min, and the insulation time is 240min; cool naturally to room temperature, wash with deionized water until neutral; place in an oven at 90°C for 12h;

[0067] Step 3: The powder obtained by drying in step 2 is added to a disodium ethylenediaminetetraacetic acid solution and a sodium dodecyl sulfate solution at a solid-liquid ratio of 1 g:10 mL. After magnetic stirring at room temperature for 12 hours, the powder is filtered and dried in an oven at 90°C for 12 hours to obtain disodium ethylenediaminetetraacetic acid modified carbon nitride for later use.

[0068] Referring to the above steps 1 to 3, the disodium ethylenediaminetetraacetic acid solution is replaced with a sodium dodecyl sulfate solution, and the other operations remain unchanged to obtain a sodium dodecyl sulfate-modified carbon nitride for later use.

[0069] 2. Preparation of modified titanium dioxide

[0070] Weigh a certain amount of analytical pure TiO 2 , soaked in 75% concentrated sulfuric acid for 24 hours. After filtering out the concentrated sulfuric acid, move it into a muffle furnace, keep it at 400℃ for 4 hours, and grind it into powder after natural cooling to obtain modified titanium dioxide.

[0071] 3. Preparation of compound preparation A

[0072] Step 1: Prepare compound preparation A for removing ammonia nitrogen from water according to the following mass fractions:

[0073]

[0074] Step 2: Weigh the modified carbon nitride and diatomaceous earth in the required ratio, and grind them in a ball mill for 30 minutes;

[0075] Step 3: Then add modified titanium dioxide and sodium sulfate in sequence, and continue grinding for 30 minutes to obtain composite preparation A.

[0076] 4. Preparation of compound preparation B:

[0077] Step 1: Prepare compound preparation B for removing ammonia nitrogen from water according to the following mass fractions:

[0078]

[0079] Step 2: Weigh the corresponding mass of modified carbon nitride and diatomaceous earth according to the required ratio, and grind them in a ball mill for 30 minutes;

[0080] Step 3: Then add modified titanium dioxide and sodium sulfate in sequence, and continue grinding for 30 minutes to obtain composite preparation B.

[0081] Prepare ammonia-containing water with an ammonia nitrogen concentration of 10 mg / L, transfer 50 mL into a 100 mL conical flask, and set up 4 groups of water to be treated:

[0082] Group 1 added 0.1g of compound preparation A for removing ammonia nitrogen from water, and group 2 added only 0.1g of disodium ethylenediaminetetraacetic acid modified carbon nitride as a comparison. After 12 hours, the ammonia nitrogen content of group 1 was 2.55mg / L, and the removal rate was 74.49%. The pH change over time was measured, and the pH decreased from 10.60 to 7.83. Figure 2 As shown; the ammonia nitrogen content in the water of Group 2 was determined to be 2.79 mg / L, and the removal rate was 72.15%.

[0083] Group 3 added 0.1g of compound preparation B for removing ammonia nitrogen from water, and group 4 added only 0.1g of sodium dodecyl sulfate modified carbon nitride as a comparison. After 12 hours, the ammonia nitrogen content of group 3 was 2.77mg / L, and the removal rate was 72.33%. The pH was measured over time, and the pH decreased from 10.60 to 7.91; the ammonia nitrogen content of group 2 was 3.19mg / L, and the removal rate was 68.12%.

[0084] It can be seen that the composite preparation for removing ammonia nitrogen from water of the present invention contains disodium ethylenediaminetetraacetic acid modified carbon nitride, which maintains good ammonia nitrogen removal ability, and the introduced modified titanium dioxide can reduce the pH of the water body, sodium sulfate has a certain bactericidal effect, and diatomaceous earth makes the components better mixed, effectively improving the water quality. It has the characteristics of diverse functions and good effects.

[0085] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A composite preparation for removing ammonia nitrogen from water, characterized in that: It is composed of the following components in mass fractions: Modified carbon nitride 75% ~ 90% Modified titanium dioxide 6% ~ 20% Diatomaceous earth 1% ~ 5% Sodium sulfate 1% ~ 2%; The modified carbon nitride is prepared by the following steps: (1) preparing a modifier solution with a concentration of 0.1 mol / L to 1 mol / L, wherein the modifier is a sodium salt or sodium hydroxide; the sodium salt is one of sodium chloride, sodium sulfate, sodium carbonate, sodium citrate, sodium dodecyl sulfate, and disodium ethylenediaminetetraacetate; (2) Weighing sodium bicarbonate and melamine in a molar ratio of 0.5:1 to 5:1, mixing them evenly, calcining them in a muffle furnace, washing them with water to neutrality after natural cooling, and drying them to obtain carbon nitride; the initial calcination temperature is 20°C to 40°C, the heating time is 150min to 180min, the insulation temperature is 500°C to 600°C, and the insulation time is 240min to 360min; the solid-liquid ratio of carbon nitride to modifier solution is 1g:(10~50)ml; (3) Add carbon nitride to the modifier solution, stir for 8-12 hours, filter, wash and dry after sufficient modification to obtain modified carbon nitride; The modified titanium dioxide is prepared by the following steps: weighing TiO2, soaking it in concentrated sulfuric acid with a mass fraction of 50% to 80% for 24 hours, keeping the soaked TiO2 in a muffle furnace at 400 to 800° C. for 4 to 8 hours, cooling it naturally, taking it out and grinding it to obtain the modified titanium dioxide.

2. A composite preparation for removing ammonia nitrogen from water according to claim 1, characterized in that: The composite preparation for removing ammonia nitrogen in water is composed of the following components by mass fraction: Modified carbon nitride 85% Modified titanium dioxide 8% Diatomaceous earth 5% Sodium sulfate 2%.

3. The method for preparing the composite preparation for removing ammonia nitrogen from water according to claim 1 or 2, characterized in that: The following steps are involved: (1) Weigh the corresponding mass of modified carbon nitride and diatomaceous earth according to the required ratio and grind them in a ball mill for 30 minutes; (2) Then, modified titanium dioxide and sodium sulfate are added in sequence, and grinding is continued for 30 minutes to obtain the composite preparation for removing ammonia nitrogen from water.

4. Use of the composite preparation for removing ammonia nitrogen from water according to claim 1 or 2 in treating ammonia-containing water.

5. The use according to claim 4, characterized in that: The application method comprises: placing the composite preparation for removing ammonia nitrogen in water at a dosage of 0.05 g / L to 0.5 g / L into an ammonia-containing water body, and the treatment time is 3 to 12 hours.

6. The use according to claim 4, characterized in that: The ammonia-containing water body has an ammonia nitrogen concentration of 0.5 mg / L to 50 mg / L.

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