A method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor

Abstract

The present application relates to the chemical technology field, propose a kind of method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor, comprising the following steps: S1, dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor acidification, vacuum dechlorination, secondary blowing dechlorination, neutralization, filtration, settlement treatment, liquid alkali is added, and pretreatment liquid is obtained;S2, sodium hypochlorite is added to pretreatment liquid and uniformly mixed, and copper oxide doped carbon nitride composite molecular sieve is used as catalyst to carry out catalytic oxidation, and the mother liquor after sodium hypochlorite treatment is obtained.Through the above technical scheme, the problem that the total ammonium content of the treated dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor in the related art is too high is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the chemical technology field, specifically, a method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor. BACKGROUND

[0002] In the production process of chlorinated isocyanuric acid products, the use of sodium hypochlorite to treat dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor involves the challenge of catalyst technology, which directly restricts the environmental protection and economy of the process of treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite. The core problem of the catalyst system currently used in the process of treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite is that in the complex chemical environment of high concentrations of cyanuric acid, sodium chloride and inorganic ammonium salt in the mother liquor, the traditional catalyst for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite is easily occupied by the surface active site or ion exchange, resulting in a decrease in the catalytic efficiency of treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite, and the catalyst cannot play its role in reducing the total ammonium content of the mother liquor. This leads to a too high total ammonium content in the mother liquor after catalytic oxidation.

[0003] Therefore, it is necessary to develop a new catalyst that can reduce the total ammonium content in dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, and to develop an efficient method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, which is the key to breaking through the bottleneck of chlorinated isocyanuric acid mother liquor treatment technology. SUMMARY

[0004] The present application provides a method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, which solves the problem of too high total ammonium content in the treated dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor.

[0005] The technical solution of the present application is as follows:

[0006] The present application provides a method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, which includes the following steps:

[0007] S1, acidifying, vacuum dechlorinating, secondary blowing and dechlorinating, neutralizing, filtering and settling the dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, and adding liquid alkali to obtain a pretreated liquid;

[0008] S2, adding sodium hypochlorite to the pretreated liquid and mixing uniformly, catalytically oxidizing, filtering, and obtaining a mother liquor treated with sodium hypochlorite;

[0009] The catalytic oxidation uses a catalyst;

[0010] The preparation method of the catalyst includes the following steps:

[0011] A1, mixing the molecular sieve, melamine and dimethylformamide uniformly, concentrating, drying, calcining to obtain a catalyst precursor;

[0012] A2, soaking the catalyst precursor with a lye, filtering, washing, drying, performing H exchange to obtain an H type molecular sieve;

[0013] A3, performing copper ion exchange on the H type molecular sieve to obtain a catalyst.

[0014] As a further technical solution, the mass ratio of the molecular sieve to melamine is 10:1-10, preferably 10:3-5.

[0015] As a further technical solution, copper ion exchange is performed using a copper chloride solution;

[0016] The concentration of the copper chloride solution is 0.05-1 mol / L;

[0017] The mass to volume ratio of the H type molecular sieve to the copper chloride solution is 0.05-0.2 g / mL.

[0018] As a further technical solution, the mass ratio of the catalyst to the sodium hypochlorite is 1:20-30.

[0019] As a further technical solution, the molecular sieve is a ZSM-5 molecular sieve.

[0020] As a further technical solution, the mass to volume ratio of the molecular sieve to dimethylformamide is 1 g:10-15 mL.

[0021] As a further technical solution, in step A1, the calcination temperature is 500-570 DEG C, and the time is 5-7 h.

[0022] In the method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, in the preparation process of the catalyst, the calcination temperature is 500-570 DEG C, which enables melamine to be converted into carbon nitride and interact with the active sites on the surface of the molecular sieve, and the time is 5-7 h, which ensures that the above process can be completely performed.

[0023] As a further technical solution, the lye is sodium hydroxide with a concentration of 0.05-0.1 mol / L;

[0024] The H exchange process is: adding the dried catalyst precursor into an ammonium salt solution, stirring, filtering, washing, drying, and calcining at 500-650 DEG C for 3-4 h.

[0025] As a further technical solution, the ammonium salt solution is ammonium nitrate with a concentration of 0.05-0.1 mol / L.

[0026] The stirring speed is 500-600 rpm, the temperature is 70-80 DEG C, and the time is 20-28 h.

[0027] As a further technical solution, the copper ion exchange process is: soaking H-type molecular sieve in copper chloride solution for exchange, filtering, washing, drying, and calcining at 500-600 DEG C for 3-5 h.

[0028] As a further technical solution, the soaking temperature is 40-50 DEG C, and the time is 18-20 h.

[0029] As a further technical solution, the mass-volume ratio of the catalyst precursor to the lye is 1-1.2 g / mL.

[0030] As a further technical solution, the mass-volume ratio of the catalyst precursor to the ammonium salt solution is 0.1-0.2 g / mL.

[0031] As a further technical solution, it further comprises step A4, specifically: soaking the molecular sieve after copper ion exchange in an equal volume of a mixed solution of ferric chloride, nickel chloride and manganese chloride, drying, calcining, to obtain a catalyst.

[0032] As a further technical solution, in the mixed solution of ferric chloride, nickel chloride and manganese chloride, the mass ratio of water, ferric chloride, nickel chloride and manganese chloride is 95:2:2:3-4.

[0033] As a further technical solution, in step A4, the calcining temperature is 600-650 DEG C, and the time is 4-5.5 h.

[0034] In the method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, in the preparation of the catalyst, the equal volume impregnation method is used to composite ferric chloride, nickel chloride and manganese chloride in the molecular sieve after copper ion exchange, and the ferric chloride, nickel chloride and manganese chloride are calcined to obtain three metal oxides of iron oxide, nickel oxide and manganese dioxide. The variable oxidation state of iron oxide promotes the oxidation of ammonium ions through redox cycle, enhances the adsorption and activation capacity of ammonium ions, and the redox activity of nickel oxide cooperates with iron oxide to accelerate the conversion of ammonium ions. Manganese dioxide provides a variety of oxidation states to provide a variety of electron transfer paths, cooperates with other components to oxidize ammonium ions, and promotes the decomposition of sodium hypochlorite to produce strong oxidizing active oxygen species, enhances the oxidation effect of ammonium ions, and further reduces the total ammonium content of dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor.

[0035] As a further technical solution, the pH of the pretreatment solution is 11-12.

[0036] As a further technical solution, in step S2, the molar ratio of cyanuric acid to sodium hypochlorite in the pretreatment solution is 1:7-8.

[0037] The temperature of the catalytic oxidation is 60-80 DEG C, and the time is 2-3h.

[0038] The working principle and beneficial effects of the present application are as follows:

[0039] In the present application, a catalyst is introduced in the process of treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite. The catalyst is first compounded with nitrogen carbide, and then subjected to H exchange, copper ion exchange and further compounding with copper oxide. Due to the special electronic structure and chemical activity of nitrogen carbide, the active center with excellent adsorption function can be formed after the combination with molecular sieve, which has high adsorption selectivity and adsorption capacity for ammonium-containing substances in the mother liquor. The introduction of copper oxide improves the treatment efficiency of the catalyst for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor with sodium hypochlorite, thereby effectively reducing the total ammonium content in the treated mother liquor. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0041] In the following examples and comparative examples, melamine was purchased from Suzhou Tejiste Chemical Co., Ltd., with the product number T-12. The specific surface area of ZSM-5 molecular sieve was 350m 2 / g, and the pore size was 0.5nm, which was purchased from Raodong (Liaoning) New Material Co., Ltd.

[0042] Example 1

[0043] A method for treating dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, comprising the following steps:

[0044] S1, acidifying, vacuum dechlorinating, secondary blowing dechlorinating, neutralizing, filtering and settling the dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor, adding liquid alkali to adjust the pH to 12 to obtain a pretreatment solution;

[0045] S2, adding sodium hypochlorite to the pretreatment solution and mixing uniformly (the molar ratio of cyanuric acid to sodium hypochlorite in the pretreatment solution is 1:8), and catalytically oxidizing at 80 DEG C for 2h to obtain a mother liquor treated with sodium hypochlorite;

[0046] A catalyst is used in the catalytic oxidation, and the mass ratio of the catalyst to sodium hypochlorite is 1:30. The preparation method of the catalyst comprises the following steps:

[0047] A1, ZSM-5 molecular sieve, melamine and dimethylformamide are uniformly mixed (the mass-volume ratio of the molecular sieve to dimethylformamide is 1 g:10 mL, and the mass ratio of the molecular sieve to melamine is 10:1), calcined at 570 DEG C for 5h, to obtain a catalyst precursor;

[0048] A2, the catalyst precursor is soaked with 0.1 mol / L sodium hydroxide (the mass-volume ratio of the catalyst precursor to the lye is 1.2 g / mL), washed, dried, and the dried catalyst precursor is added to a 0.1 mol / L ammonium nitrate solution (the mass-volume ratio of the catalyst precursor to the ammonium nitrate solution is 0.2 g / mL), stirred at 600 rpm at 80 DEG C for 20h, filtered, washed, dried, and calcined at 650 DEG C for 3h to obtain an H-type molecular sieve;

[0049] A3, the H-type molecular sieve is soaked in a 0.1 mol / L copper chloride solution at 50 DEG C for 18h (the mass-volume ratio of the H-type molecular sieve to the copper chloride solution is 0.2 g / mL), concentrated, dried, and calcined at 600 DEG C for 3h to obtain a catalyst.

[0050] Example 2

[0051] A method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor, comprising the following steps:

[0052] S1, the dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor is acidified, vacuum dechlorinated, secondary blowing dechlorinated, neutralized, filtered, and settled, liquid caustic is added to adjust the pH to 11, and a pretreated liquid is obtained;

[0053] S2, sodium hypochlorite is added to the pretreated liquid and uniformly mixed (the molar ratio of cyanuric acid to sodium hypochlorite in the pretreated liquid is 1:7), and catalytic oxidation is carried out at 60 DEG C for 3h to obtain a sodium hypochlorite treated mother liquor;

[0054] A catalyst is used during catalytic oxidation, and the mass ratio of the catalyst to sodium hypochlorite is 1:20, and the preparation method of the catalyst comprises the following steps:

[0055] A1, ZSM-5 molecular sieve, melamine and dimethylformamide are uniformly mixed (the mass-volume ratio of the molecular sieve to dimethylformamide is 1 g:15 mL, and the mass ratio of the molecular sieve to melamine is 10:1), calcined at 500 DEG C for 7h, to obtain a catalyst precursor;

[0056] A2, the catalyst precursor is soaked with 0.05 mol / L sodium hydroxide (the mass-volume ratio of the catalyst precursor to the lye is 1 g / mL), washed, dried, and then added to 0.05 mol / L ammonium nitrate solution (the mass-volume ratio of the catalyst precursor to the ammonium nitrate solution is 0.1 g / mL), stirred at 500 rpm for 28 h at 70°C, filtered, washed, dried, and calcined at 500°C for 4 h to obtain H-type molecular sieves;

[0057] A3, the H-type molecular sieves are soaked in 0.05 mol / L copper chloride solution at 40°C for 20 h (the mass-volume ratio of the H-type molecular sieves to the copper chloride solution is 0.05 g / mL), concentrated, dried, and calcined at 500°C for 5 h to obtain the catalyst.

[0058] Example 3

[0059] The difference between this example and Example 2 is only that the mass ratio of the molecular sieves to melamine in this example is 1:1.

[0060] Example 4

[0061] The difference between this example and Example 2 is only that the mass ratio of the molecular sieves to melamine in this example is 10:3.

[0062] Example 5

[0063] The difference between this example and Example 2 is only that the mass ratio of the molecular sieves to melamine in this example is 2:1.

[0064] Example 6

[0065] The difference between this example and Example 5 is only that the preparation method of the catalyst in this example further includes the following steps:

[0066] A4, the molecular sieves after copper ion exchange are soaked in an equal volume of a mixed solution of iron chloride, nickel chloride, and manganese chloride (prepared from water, iron chloride, nickel chloride, and manganese chloride with a mass ratio of 95:2:2:4), dried, and calcined at 650°C for 4 h to obtain the catalyst.

[0067] Example 7

[0068] The difference between this example and Example 5 is only that the preparation method of the catalyst in this example further includes the following steps:

[0069] A4, the molecular sieves after copper ion exchange are soaked in an equal volume of a mixed solution of iron chloride, nickel chloride, and manganese chloride (prepared from water, iron chloride, nickel chloride, and manganese chloride with a mass ratio of 95:2:2:3), dried, and calcined at 600°C for 4.5 h to obtain the catalyst.

[0070] Comparative Example 1

[0071] The difference between the present comparative example and Example 2 is only that the preparation method of the catalyst of the present comparative example comprises the following steps:

[0072] The ZSM-5 molecular sieve, melamine and dimethylformamide were mixed uniformly (the mass-volume ratio of the molecular sieve to dimethylformamide was 1 g: 15 mL, and the mass ratio of the molecular sieve to melamine was 10: 1), calcined at 500 ℃ for 7 h to obtain the catalyst.

[0073] Comparative Example 2

[0074] The difference between the present comparative example and Example 2 is only that the preparation method of the catalyst of the present comparative example comprises the following steps:

[0075] A1, the ZSM-5 molecular sieve was soaked with 0.05 mol / L sodium hydroxide (the mass-volume ratio of the catalyst precursor to the lye was 1 g / mL), washed, dried, and the dried catalyst precursor was added to a 0.05 mol / L ammonium nitrate solution (the mass-volume ratio of the catalyst precursor to the ammonium nitrate solution was 0.1 g / mL), stirred at 500 rpm at 70 ℃ for 28 h, filtered, washed, dried, and calcined at 500 ℃ for 4 h to obtain the H-type molecular sieve;

[0076] A2, the H-type molecular sieve was soaked in a 0.05 mol / L copper chloride solution at 40 ℃ for 20 h (the mass-volume ratio of the H-type molecular sieve to the copper chloride solution was 0.05 g / mL), concentrated, dried, and calcined at 500 ℃ for 5 h to obtain the catalyst.

[0077] Comparative Example 3

[0078] The difference between the present comparative example and Example 2 is only that the catalyst of the present comparative example is a ZSM-5 molecular sieve.

[0079] Experimental Example

[0080] The mother liquor after the sodium hypochlorite treatment obtained in Examples 1-7 and Comparative Examples 1-3 was determined for the ammonium content, and the test method was as follows: Nessler's reagent spectrophotometry: the organic ammonia in the sample was converted into inorganic ammonium in a concentrated sulfuric acid solution by adding a catalyst and heating, the inorganic ammonium was evaporated in the form of ammonia under alkaline conditions, and after being absorbed by a boric acid solution, Nessler's reagent was added for color development, and the colored solution was determined by photometry at a wavelength of 420 nm. The test results are shown in Table 1.

[0081] Table 1 Test results of total ammonium content

[0082]

[0083] From Table 1, it can be seen that, compared with Comparative Examples 1-3, Examples 1-5 illustrate that, by preparing the copper oxide-doped carbon nitride composite molecular sieve, the total ammonium content of the treated dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor is reduced.

[0084] Compared with Example 5, Examples 6-7 illustrate that, by further compounding iron oxide, nickel oxide and manganese dioxide in the copper ion-exchanged molecular sieve, the total ammonium content of the treated dichloroisocyanuric acid and trichloroisocyanuric acid mother liquor is further reduced.

[0085] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor, characterized by, The method comprises the following steps: S1, dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor acidification, vacuum dechlorination, secondary blowing dechlorination, neutralization, filtration, sedimentation treatment, adding liquid alkali, and obtaining a pretreated liquid; S2, adding sodium hypochlorite to the pretreated liquid and mixing uniformly, catalytic oxidation, and filtering to obtain a sodium hypochlorite treated mother liquor; in step S2, the molar ratio of cyanuric acid in the pretreated liquid to the sodium hypochlorite is 1:7-8; The catalytic oxidation is catalyzed by using a catalyst; The preparation method of the catalyst comprises the following steps: A1, mixing molecular sieve, melamine and dimethylformamide uniformly, concentrating, drying, calcining to obtain a catalyst precursor; the molecular sieve is ZSM-5 molecular sieve; A2, soaking the catalyst precursor with lye, filtering, washing, drying, H exchange to obtain H type molecular sieve; A3, copper ion exchange of the H type molecular sieve to obtain a catalyst; The process of H exchange is: adding the dried catalyst precursor into an ammonium salt solution, stirring, filtering, washing, drying, and calcining at 500-650 DEG C for 3-4 h.

2. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, Copper chloride solution is used for copper ion exchange; The concentration of the copper chloride solution is 0.05-1 mol / L; The mass-volume ratio of the H type molecular sieve and the copper chloride solution is 0.05-0.2 g / mL.

3. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, In step A1, the calcination temperature is 500-570 DEG C, and the time is 5-7 h.

4. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, The lye is a sodium hydroxide solution with a concentration of 0.05-0.1 mol / L.

5. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, The process of copper ion exchange is: soaking the H type molecular sieve in the copper chloride solution for exchange, filtering, washing, drying, and calcining at 500-600 DEG C for 3-5 h.

6. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, Step A4 is further included, specifically: immersing the molecular sieve after copper ion exchange in an equal volume of a mixed solution of ferric chloride, nickel chloride and manganese chloride, drying, calcining to obtain a catalyst.

7. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 6, characterized in that, In the mixed solution of ferric chloride, nickel chloride and manganese chloride, the mass ratio of water, ferric chloride, nickel chloride and manganese chloride is 95:2:2:3-4.

8. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 7, characterized in that, In step A4, the calcination temperature is 600-650 DEG C, and the time is 4-4.5 h.

9. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, The pH of the pretreated liquid is 11-12.

10. The method for treating dichloroisocyanuric acid, trichloroisocyanuric acid mother liquor according to claim 1, characterized in that, The temperature of the catalytic oxidation is 60-80 DEG C, and the time is 2-3 h.

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