Comprehensive utilization method of acidic wastewater containing phosphorus and sulfur

Abstract

The invention discloses a comprehensive utilization method of acidic wastewater containing phosphorus and sulfur, and belongs to the field of comprehensive utilization of acidic wastewater containing phosphorus and sulfur. A comprehensive utilization method of acidic wastewater containing phosphorus and sulfur comprises the following steps: S1, taking a certain volume of production wastewater of a fine chemical diazonium deamination reaction as a raw material, adding water for dilution, filtering, collecting filtrate, controlling the reaction temperature, and introducing ammonia gas into the filtrate to adjust the pH value; s2, a Fe-MImCl / C catalyst and hydrogen peroxide are added into the production wastewater treated in the step S1, stirring and suction filtration are conducted, filtrate is obtained for standby application, and the solid is the Fe-MImCl / C catalyst; and S3, introducing ammonia gas into the filtrate obtained in the step S2 until the pH value is 5-6, and carrying out rotary evaporation to obtain the ammonium sulfate-ammonium phosphate compound fertilizer. According to the method, the phosphorus and sulfur-containing acidic wastewater generated in the fine chemical industry can be effectively utilized, the environmental protection pressure is relieved, and the resource utilization of wastes is realized.

Description

Technical Field

[0001] The invention relates to the field of comprehensive utilization of acidic wastewater containing phosphorus and sulfur, and more specifically, to a comprehensive utilization method of acidic wastewater containing phosphorus and sulfur. Background Art

[0002] According to incomplete statistics, the fine chemical industry alone produces more than 25,000 tons of phosphorus-containing sulfuric acid wastewater each year due to diazo deamination reactions. The traditional treatment method is chemical precipitation, which converts sulfur and phosphorus into inorganic salts and then landfills them. Since the wastewater contains a large amount of phosphorus and sulfur elements, it is a huge waste if they are not used as resources.

[0003] Ammonium thiophosphate is a compound fertilizer that integrates the three major nutrients of nitrogen, phosphorus and sulfur. Its unique advantage lies in its balanced nutritional ratio, which can fully meet the needs of plant growth. It is suitable for a variety of crops such as corn, wheat, and soybeans, and has a large market space. Phosphorus and nitrogen are one of the macroelements necessary for plant growth. Although sulfur is not as widely recognized as a macroelement as nitrogen, phosphorus, and potassium, it is also a necessary component for plants to synthesize proteins, amino acids and other substances. It also has a positive effect on improving plant resistance and quality. Compared with other chemical fertilizers, the notable feature of ammonium thiophosphate is its comprehensive nutrient supply capacity, which can effectively improve fertilizer utilization and promote crop yield and quality improvement.

[0004] Therefore, it is necessary to provide a method for treating production wastewater from diazo deamination reaction in the fine chemical industry, by which ammonium thiophosphate compound fertilizer for plant growth can be prepared. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for comprehensive utilization of phosphorus-sulfur-containing acidic wastewater, which can effectively utilize the phosphorus-sulfur-containing acidic wastewater generated in the fine chemical industry, reduce environmental pressure, realize the resource utilization of waste, and promote the sustainable development of the fine chemical industry.

[0006] To solve the above problems, the present invention adopts the following technical solutions.

[0007] A comprehensive utilization method of acidic wastewater containing phosphorus and sulfur comprises the following steps: S1: Take a certain volume of production wastewater from the diazo deamination reaction of fine chemicals as raw material, dilute with water, filter, collect the filtrate, control the reaction temperature and introduce ammonia into the filtrate to adjust the pH; S2: adding Fe-MImCl / C catalyst and hydrogen peroxide to the production wastewater treated in step S1, stirring, filtering, and the filtrate is set aside; S3: Ammonia gas is introduced into the filtrate of step S2 until the pH value is 5-6, and the ammonium thiophosphate compound fertilizer is obtained by rotary evaporation.

[0008] Furthermore, in the production wastewater of the fine chemical diazo deamination reaction, the phosphate ion content is 2.2~3.0 mol / L, the sulfate ion content is 2.0~3.5 mol / L and the hydrogen ion concentration is 8.0~12.0 mol / L, and the rest is a small amount of sodium ions and other ions.

[0009] Furthermore, the volume ratio of water added for dilution in step S1 to production wastewater is 3.0-5.0:1.

[0010] Furthermore, in the step S2, the weight ratio of the Fe-MImCl / C catalyst to the production wastewater is 0.01-0.03:1.

[0011] Furthermore, in step S2, the concentration of hydrogen peroxide is 30%, and the volume ratio of hydrogen peroxide to production wastewater is 0.1-0.2:1.

[0012] Furthermore, in the step S1, the reaction temperature is 15-30°C; ammonia gas is introduced to adjust the pH to 3-5.

[0013] Furthermore, in the step S2, the stirring time is 2 to 5 h.

[0014] Further, the preparation method of the Fe-MImCl / C catalyst in the S2 step is as follows: A1: In an ethanol solution, N-methylimidazole and hydrochloric acid are stirred to form a salt, FeCl3 is added to react for 0.5-1h, and then activated carbon is added and stirred for 8-10h to obtain a mixture; A2: The mixture obtained in step A1 is subjected to rotary evaporation, dried, and then calcined under a nitrogen atmosphere; after the calcination, it is soaked in sulfuric acid, washed with clean water and dried to obtain a Fe-MImCl / C catalyst.

[0015] Furthermore, in step A1, the molar ratio of N-methylimidazole, hydrochloric acid and FeCl3 is 1:1.0~1.1:0.2~0.4.

[0016] Furthermore, the preparation method of the Fe-MImCl / C catalyst is preferably as follows: in an ethanol solution, N-methylimidazole and hydrochloric acid are stirred to react with salt, FeCl3 is added to react for 0.5-1 h, activated carbon is added, stirring is continued for 8-10 h, ethanol is removed by rotary evaporation, and the sample is dried at 90-110 °C in a vacuum oven for 3-4 h, and the dried sample is calcined at 800-1000 °C in a nitrogen atmosphere for 4-7 h, and the calcined sample is soaked in 0.5 mol / L sulfuric acid for 1-3 h, and the sample is washed with clean water until neutral, and dried at 90-110 °C in a vacuum oven for 4-5 h for use.

[0017] Compared with the prior art, the advantages of the present invention are: 1. This scheme uses the acidic wastewater containing phosphorus and sulfur produced in the fine chemical industry as raw materials to prepare ammonium thiophosphate compound fertilizer, which can reduce the cost of wastewater disposal and avoid wastewater pollution to the environment. In addition, this scheme can effectively utilize phosphorus and sulfur resources and reduce the preparation cost of ammonium thiophosphate compound fertilizer.

[0018] 2. The ammonium thiophosphate compound fertilizer prepared in this scheme has a high proportion of water-soluble phosphorus, which is beneficial to plant absorption.

[0019] 3. The Fe-MImCl / C catalyst provided in this scheme can be reused and will not introduce iron ions into the system. DETAILED DESCRIPTION

[0020] (I) The preparation method of the catalyst Fe-MImCl / C is as follows: Add 24.6 g N-methylimidazole and 25 mL concentrated hydrochloric acid to 500 mL ethanol and stir at room temperature for 0.5 h; add 16.2 g FeCl3 and continue stirring for 0.5 h; then add 100 g activated carbon and continue stirring for 8 h; remove ethanol by rotary evaporation and dry in a vacuum oven at 100 °C for 3 h; the dried sample is calcined at 900 °C for 5 h in a nitrogen atmosphere, the calcined sample is soaked in 0.5 mol / L sulfuric acid for 2 h, the sample is washed with clean water until neutral, and dried in a vacuum oven at 100 °C for 4 h for use.

[0021] Embodiment 1:

[0022] Take 100 mL of production wastewater (158 g) from fine chemical diazo deamination reaction, the phosphate ion content in the wastewater is 2.25 mol / L, the sulfate ion content is 2.46 mol / L and the hydrogen ion concentration is 10.08 mol / L. Dilute with 400 mL of water, filter and remove solid impurities; slowly pass ammonia into the filtrate, control the solution temperature at 15~30 ℃, until the solution pH is 3.8; add 3 g of the prepared Fe-MImCl / C catalyst and 15 mL of 30% hydrogen peroxide to the solution, stir at room temperature for 3 h, filter, and Fe-MImCl / C can be reused; continue to slowly pass ammonia into the filtrate, control the solution temperature at 15~30 ℃, until the pH is 5.6, and remove water by rotary evaporation to obtain 63.1 g of ammonium thiophosphate compound fertilizer; the mass fraction of total nitrogen is 21.6%, the mass fraction of available phosphorus (P2O5) is 25.3%, the mass fraction of sulfur is 12.8%, and the moisture content is 1.8%.

[0023] Embodiment 2:

[0024] Take 100 mL of production wastewater (160 g) from the fine chemical diazo deamination reaction. The phosphate ion content, sulfate ion content and hydrogen ion concentration in the wastewater are 2.33 mol / L, 2.57 mol / L and 10.93 mol / L. Dilute with 400 mL of water, filter and remove solid impurities; slowly pass ammonia into the filtrate, control the solution temperature at 15-30 °C, until the solution pH is 4.0; add 2.4 g of the prepared Fe-MImCl / C catalyst and 16 mL of 30% hydrogen peroxide to the solution, stir at room temperature for 4 h, filter, and Fe-MImCl / C can be reused; continue to slowly pass ammonia into the filtrate, control the solution temperature at 15-30 °C, until the pH is 5.8, and remove water by rotary evaporation to obtain 64.6 g of ammonium thiophosphate compound fertilizer; the mass fraction of total nitrogen is greater than 23.6%, the mass fraction of available phosphorus (P2O5) is 25.6%, the mass fraction of sulfur is 12.7%, and the moisture content is 1.6%.

[0025] Embodiment 3:

[0026] Take 100 mL of production wastewater (168 g) from the fine chemical diazo deamination reaction. The phosphate ion content in the wastewater is 2.35 mol / L, the sulfate ion content is 2.80 mol / L, and the hydrogen ion concentration is 11.74 mol / L. Dilute with 400 mL of water, filter and remove solid impurities; slowly pass ammonia into the filtrate, control the solution temperature at 15-30 °C, until the solution pH is 4.4; add 3.6 g of the prepared Fe-MImCl / C catalyst and 16 mL of 30% hydrogen peroxide to the solution, stir at room temperature for 3 h, filter, and Fe-MImCl / C can be reused; continue to slowly pass ammonia into the filtrate, control the solution temperature at 15-30 °C, until the pH is 5.7, and remove water by rotary evaporation to obtain 69.1 g of ammonium thiophosphate compound fertilizer; the mass fraction of total nitrogen is greater than 23.8%, the mass fraction of available phosphorus (P2O5) is 24.1%, the mass fraction of sulfur is 12.9%, and the moisture content is 1.9%.

[0027] Embodiment 4:

[0028] Take 100 mL of production wastewater (168 g) from the fine chemical diazo deamination reaction. The phosphate ion content in the wastewater is 2.35 mol / L, the sulfate ion content is 2.80 mol / L, and the hydrogen ion concentration is 11.74 mol / L. Dilute with 400 mL of water, filter and remove solid impurities; slowly pass ammonia into the filtrate, control the solution temperature at 15-30 ° C, until the solution pH is 4.2; add the Fe-MImCl / C catalyst recovered in Example 3 and 18 mL of 30% hydrogen peroxide to the solution, stir at room temperature for 3.5 h, filter with suction, and Fe-MImCl / C can be reused; continue to slowly pass ammonia into the filtrate, control the solution temperature at 15-30 ° C, until the pH is 5.5, and remove moisture by rotary evaporation to obtain 68.8 g of ammonium thiophosphate compound fertilizer; the mass fraction of total nitrogen is greater than 23.9%, the mass fraction of available phosphorus (P2O5) is 24.2%, the mass fraction of sulfur is 13.0%, and the moisture content is 1.6%.

Claims

1. A method for comprehensive utilization of acidic wastewater containing phosphorus and sulfur, characterized in that: The following steps are involved: S1: Take a certain volume of production wastewater from the diazo deamination reaction of fine chemicals as raw material, dilute with water, filter, collect the filtrate, control the reaction temperature and introduce ammonia into the filtrate to adjust the pH; S2: adding Fe-MImCl / C catalyst and hydrogen peroxide to the production wastewater treated in step S1, stirring, filtering, and the filtrate is set aside; S3: Ammonia gas is introduced into the filtrate of step S2 until the pH value is 5-6, and then the ammonium thiophosphate compound fertilizer is obtained by rotary evaporation.

2. The method for comprehensive utilization of acidic wastewater containing phosphorus and sulfur according to claim 1, characterized in that: The volume ratio of the water added for dilution in step S1 to the production wastewater is 3.0-5.0:

1.

3. The comprehensive utilization method of a phosphorus-sulfur-containing acidic wastewater according to claim 1, characterized in that: In the step S2, the weight ratio of the Fe-MImCl / C catalyst to the production wastewater is 0.01-0.03:

1.

4. The comprehensive utilization method of a phosphorus-sulfur-containing acidic wastewater according to claim 1, characterized in that: In the step S2, the concentration of hydrogen peroxide is 30%, and the volume ratio of hydrogen peroxide to production wastewater is 0.1-0.2:

1.

5. The method for comprehensive utilization of phosphorus-sulfur-containing acidic wastewater according to claim 1, characterized in that: In the step S1, the reaction temperature is 15-30°C; ammonia gas is introduced to adjust the pH to 3-5.

6. The comprehensive utilization method of phosphorus-sulfur-containing acidic wastewater according to claim 1, characterized in that: In the step S2, the stirring time is 2 to 5 h.

7. The comprehensive utilization method of phosphorus-sulfur-containing acidic wastewater according to claim 1, characterized in that: The preparation method of the Fe-MImCl / C catalyst in the S2 step is as follows: A1: In an ethanol solution, N-methylimidazole and hydrochloric acid are stirred to form a salt, FeCl3 is added to react for 0.5-1 h, and then activated carbon is added and stirred for 8-10 h to obtain a mixture; A2: The mixture obtained in step A1 is subjected to rotary evaporation, dried, and then calcined under a nitrogen atmosphere; after the calcination, it is soaked in sulfuric acid, washed with clean water and dried to obtain a Fe-MImCl / C catalyst.

8. The method for comprehensive utilization of acidic wastewater containing phosphorus and sulfur according to claim 7, characterized in that: In the step A1, the molar ratio of N-methylimidazole, hydrochloric acid and FeCl3 is 1:1.0~1.1:0.2~0.4.