Treatment method of hydroxylamine-containing waste liquid

Abstract

The invention relates to a treatment method of hydroxylamine-containing waste liquid. The treatment method comprises the following steps: (1) mixing a transition metal catalyst with hydroxylamine-containing waste liquid to obtain mixed liquid, and carrying out self-decomposition reaction; (2) maintaining the pH value of the mixed solution at 9.0-10.5 in the self-decomposition reaction process; and (3) after the self-decomposition reaction is finished, carrying out solid-liquid separation to obtain the hydroxylamine-removed waste liquid. The chemical environment during hydroxylamine decomposition reaction is alkaline, the condition is easy to realize, and the use amount of acid is greatly reduced. Meanwhile, the amount of added simple substances and compounds containing metal elements is small, and the amount of generated corresponding metal-containing reaction waste is small. And finally, the heat required by the reaction can be completely provided by the heat released by the decomposition of the hydroxylamine, and the self-decomposition of the hydroxylamine can be realized without additional energy.

Description

Technical Field

[0001] The present invention relates to the technical field of organic waste liquid treatment, in particular to a method for treating hydroxylamine-containing waste liquid. Background Art

[0002] High-concentration organic waste liquid containing hydroxylamine is often produced in industrial production. This type of waste liquid has strong reducing properties and potential instability. Improper treatment can easily lead to safety and environmental risks. The existing hydroxylamine waste liquid treatment process is mainly aimed at low-concentration systems. Usually, the pH of the waste liquid needs to be adjusted to a strong acidity first. This process consumes a large amount of inorganic acid and uses the acidic environment to dissolve metal elements. The metal ions produced by the dissolution catalyze the decomposition of hydroxylamine. CN109205840A discloses a method for treating hydroxylamine wastewater, which comprises adjusting the pH of the hydroxylamine wastewater to be treated to 2-8; adding a catalytic amount of trivalent iron ion component and stirring, wherein the catalytic amount refers to the weight of the trivalent iron ion being 0.5-5% of the weight of the hydroxylamine component; adding hydrogen peroxide dropwise and stirring until the system has no obvious heat release, and the reaction is terminated. CN108217901A discloses a method for degrading hydroxylamine and / or hydroxylamine salts in wastewater, comprising adjusting the acidity of wastewater containing hydroxylamine and / or hydroxylamine salts until the acidity of the wastewater is 34,000 to 272,000 mg KOH / g; passing the resulting wastewater through a reactor containing an iron-containing compound, wherein the iron-containing compound is insoluble in water and can ionize to produce Fe under acidic conditions, and the reaction is continued for 20 to 60 minutes. 3+ Iron-containing compounds can continuously degrade hydroxylamine and / or hydroxylamine salts in wastewater.

[0003] However, this existing process consumes a significant amount of acid, resulting in high treatment costs and the potential for secondary pollution. Furthermore, the system is poorly adaptable to high-concentration hydroxylamine and exhibits low efficiency. Therefore, there is an urgent need to develop an efficient and economical treatment technology for high-concentration hydroxylamine wastewater that can significantly reduce acid usage and significantly reduce the use of metal additives. Summary of the Invention

[0004] To solve the above technical problems, the present invention uses a transition metal catalyst to induce the self-decomposition of hydroxylamine under alkaline conditions, thereby achieving efficient treatment of high-concentration hydroxylamine waste liquid.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for treating hydroxylamine-containing waste liquid, the method comprising:

[0007] (1) mixing a transition metal catalyst with a hydroxylamine-containing waste liquid to obtain a mixed liquid and subjecting it to a self-decomposition reaction;

[0008] (2) During the autolysis reaction, the pH of the mixed solution is maintained at 9.0-10.5, for example, 9.0, 9.2, 9.4, 9.6, 9.8, 10 or 10.5, to carry out the autolysis reaction;

[0009] (3) After the autolysis reaction is completed, solid-liquid separation is performed to obtain dehydroxylamine waste liquid.

[0010] The present invention uses a transition metal catalyst to reduce the energy barrier that needs to be overcome for the self-decomposition reaction to occur, forms an unstable intermediate through the transition metal element and hydroxylamine, and triggers the self-decomposition reaction of hydroxylamine under alkaline conditions. During the self-decomposition reaction, a small amount of pH regulator is continuously added to promote the self-decomposition reaction and maintain the system at a pH suitable for self-decomposition. At the same time, the problem of excessive acid consumption is solved, and hydroxylamine in waste liquid is removed efficiently.

[0011] The present invention has no limitation on the solid-liquid separation, and any method known to those skilled in the art for solid-liquid separation may be used, such as filtration, sedimentation or centrifugation.

[0012] As a preferred technical solution of the present invention, the metal catalyst includes any one of a transition metal element, a transition metal oxide and a transition metal salt, or a combination of at least two of them.

[0013] As a preferred technical solution of the present invention, the transition metal element includes any one of iron, copper, cobalt and nickel, or a combination of at least two of them.

[0014] As a preferred technical solution of the present invention, the transition metal oxide includes any one of iron oxide, copper oxide, cobalt oxide and nickel oxide, or a combination of at least two thereof.

[0015] As a preferred technical solution of the present invention, the transition metal salt includes any one or a combination of at least two of ferric chloride, cupric chloride, cobalt chloride, nickel chloride, ferric sulfate, ferrous sulfate, cupric sulfate, cobalt sulfate and nickel sulfate, preferably ferrous sulfate or cupric chloride.

[0016] The present invention uses transition metal elements, transition metal oxides and transition metal salts as transition metal catalysts, which can trigger the self-decomposition reaction of hydroxylamine under alkaline conditions. The heat generated by the decomposition of hydroxylamine can be used to maintain the reaction without the need to introduce additional new heat.

[0017] As a preferred technical solution of the present invention, the hydroxylamine content of the hydroxylamine-containing waste liquid is 2%-15% by mass, for example, 2%, 6%, 8%, 10% or 15%.

[0018] The treatment method of the present invention is applicable to waste liquid with a relatively high hydroxylamine concentration, and the autodecomposition reaction is more easily carried out in the waste liquid with a high concentration.

[0019] Preferably, the pH value of the hydroxylamine-containing waste liquid is 10-12, for example, it can be 10, 10.5, 11, 11.5 or 12.

[0020] Preferably, the components of the hydroxylamine-containing waste liquid include hydroxylamine, ethanolamine, isopropanolamine and additives.

[0021] Preferably, the additive comprises bisalic acid and / or catechol.

[0022] As a preferred technical solution of the present invention, the addition amount of the transition metal catalyst is 3wt%-6wt% of the hydroxylamine-containing waste liquid, for example, it can be 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt% or 6wt%.

[0023] The present invention controls the rate of the self-decomposition reaction by controlling the amount of the transition metal catalyst, thereby avoiding safety accidents caused by overheating of the reaction, while ensuring a good catalytic effect and fully removing hydroxylamine from the hydroxylamine-containing waste liquid.

[0024] As a preferred technical solution of the present invention, the self-decomposition reaction time is 4-6 hours, for example, it can be 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours.

[0025] Preferably, stirring is performed during the autolysis reaction.

[0026] Preferably, no heating is performed during the autolysis reaction.

[0027] As a preferred technical solution of the present invention, a pH regulator is continuously added during the autodecomposition reaction to maintain the pH of the mixed solution.

[0028] Preferably, the pH adjuster comprises sulfuric acid.

[0029] The present invention detects the pH value of the system during the autolysis reaction, and adjusts the timing and amount of adding the pH regulator according to the change of the pH value in the system to maintain a sustainable, efficient and mild autolysis reaction in the system.

[0030] As a preferred technical solution of the present invention, the processing method includes:

[0031] (1) mixing a transition metal catalyst with a hydroxylamine-containing waste liquid having a hydroxylamine content of 2% to 15% by mass to obtain a mixed liquid to initiate a self-decomposition reaction, wherein the amount of the transition metal catalyst added is 3% to 6% by mass of the hydroxylamine-containing waste liquid;

[0032] (2) During the autolysis reaction, sulfuric acid was continuously added to adjust the pH of the mixture to 9-10.5 and stirred to carry out the autolysis reaction for 4-6 hours;

[0033] (3) After the autolysis reaction is completed, solid-liquid separation is performed to obtain dehydroxylamine waste liquid.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] (1) The method for treating hydroxylamine-containing waste liquid provided by the present invention can decompose hydroxylamine in organic waste liquid with high concentration of hydroxylamine, and catalyze the self-decomposition reaction of hydroxylamine by adding a transition metal catalyst.

[0036] (2) The method for treating hydroxylamine-containing waste liquid provided by the present invention is carried out under alkaline conditions, and the decomposition of hydroxylamine at a high pH value can be achieved using as little acid as possible. The heat generated by the decomposition of hydroxylamine is used to maintain the reaction without the need to introduce additional new heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 1 is a flow chart of a method for treating hydroxylamine-containing waste liquid provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0039] Example 1

[0040] The present embodiment provides a method for treating hydroxylamine-containing organic waste liquid, the method comprising: (1) mixing ferrous sulfate heptahydrate with hydroxylamine-containing waste liquid having a hydroxylamine content of 10% by mass to obtain a mixed liquid, wherein the amount of ferrous sulfate heptahydrate added is 5 wt % of the hydroxylamine-containing waste liquid, and the pH value of the hydroxylamine-containing waste liquid is 11.9; (2) during the autolysis reaction, continuously and slowly adding sulfuric acid to adjust the pH of the mixed liquid to 10, stirring, and performing the autolysis reaction for 5 hours; and (3) after the autolysis reaction is completed, performing filter pressing to remove precipitated solids to obtain the dehydroxylamine waste liquid.

[0041] Example 2

[0042] The present embodiment provides a method for treating hydroxylamine-containing organic waste liquid, the method comprising: (1) mixing a mixed powder of ferrous sulfate heptahydrate and copper powder with hydroxylamine-containing waste liquid having a hydroxylamine content of 2% by mass to obtain a mixed liquid, wherein the amount of the mixed powder added is 6 wt % of the hydroxylamine-containing waste liquid, and the pH value of the hydroxylamine-containing waste liquid is 10; (2) during the autodecomposition reaction, continuously and slowly adding sulfuric acid to adjust the pH of the mixed liquid to 9, stirring, and performing the autodecomposition reaction for 4 hours; and (3) after the autodecomposition reaction is completed, performing filter pressing to remove precipitated solids to obtain dehydroxylamine waste liquid.

[0043] Example 3

[0044] The present embodiment provides a method for treating hydroxylamine-containing organic waste liquid, the method comprising: (1) mixing ferrous sulfate heptahydrate with hydroxylamine-containing waste liquid having a hydroxylamine content of 15% by mass to obtain a mixed liquid, wherein the amount of ferrous sulfate heptahydrate added is 3 wt % of the hydroxylamine-containing waste liquid, and the pH value of the hydroxylamine-containing waste liquid is 12; (2) during the autolysis reaction, continuously and slowly adding sulfuric acid to adjust the pH of the mixed liquid to 10.5, stirring, and performing the autolysis reaction for 6 hours; and (3) after the autolysis reaction is completed, performing filter pressing to remove precipitated solids to obtain the dehydroxylamine waste liquid.

[0045] Example 4

[0046] This embodiment provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as that of Example 1, except that ferrous sulfate heptahydrate in step (1) is replaced by an equal mass of ferric oxide.

[0047] Example 5

[0048] This embodiment provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as that of Example 1, except that ferrous sulfate heptahydrate in step (1) is replaced by ferric chloride of equal mass.

[0049] Example 6

[0050] This embodiment provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as that of Example 1, except that the ferrous sulfate heptahydrate in step (1) is replaced by an equal mass of copper chloride dihydrate.

[0051] Example 7

[0052] This embodiment provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as that of Example 1, except that the ferrous sulfate heptahydrate in step (1) is replaced by zinc chloride of equal mass.

[0053] Example 8

[0054] This embodiment provides a method for treating hydroxylamine-containing organic waste liquid. The treatment method is the same as that of Example 1, except that the amount of ferrous sulfate heptahydrate added is 7 wt % of the hydroxylamine-containing waste liquid. During the treatment process of this embodiment, the reaction is violent and liquid splashing occurs.

[0055] Example 9

[0056] This embodiment provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as that of Example 1, except that the amount of ferrous sulfate heptahydrate added is 2 wt % of the hydroxylamine-containing waste liquid.

[0057] Comparative Example 1

[0058] This comparative example provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as Example 1 except that sulfuric acid is not added.

[0059] Comparative Example 2

[0060] This comparative example provides a method for treating organic waste liquid containing hydroxylamine. The treatment method first performs step (2) of adjusting the pH, and then performs step (1) of adding ferrous sulfate heptahydrate. The rest is the same as Example 1.

[0061] Comparative Example 3

[0062] This comparative example provides a method for treating organic waste liquid containing hydroxylamine. The treatment method is the same as Example 1 except that the pH is adjusted to 5.

[0063] Test Method

[0064] The hydroxylamine content of the hydroxylamine removal waste liquid obtained in Examples 1-9 and Comparative Examples 1-3 was determined by spectrophotometry, and the hydroxylamine removal rate was calculated. The test results are shown in Table 1.

[0065] Test results

[0066] Table 1

[0067] Examples and Comparative Examples Hydroxylamine removal rate (%) Example 1 99 Example 2 98 Example 3 96 Example 4 96 Example 5 97 Example 6 92 Example 7 23 Example 8 - Example 9 51 Comparative Example 1 38 Comparative Example 2 52 Comparative Example 3 42

[0068] “-” in the table means no data.

[0069] The test results show that:

[0070] (1) It can be seen from Examples 1 to 6 that the present invention can achieve a good hydroxylamine removal effect while achieving a low acid consumption by catalyzing the self-decomposition reaction of hydroxylamine with a transition metal catalyst, and the hydroxylamine removal rate can reach more than 92%. It can be seen from Example 7 that the present invention improves the hydroxylamine removal rate by optimizing the type of transition metal catalyst.

[0071] (2) It can be seen from Examples 1 and 8-9 that the present invention can achieve a better hydroxylamine removal rate by further controlling the amount of transition metal catalyst added, and further control the reaction rate to avoid safety problems caused by excessive reaction.

[0072] (3) It can be seen from Example 1 and Comparative Examples 1-3 that the present invention promotes the self-decomposition of hydroxylamine by adjusting the pH, reduces the amount of catalyst and acid used, and achieves green and efficient removal of hydroxylamine in wastewater. When the pH is not adjusted, the hydroxylamine removal rate is reduced from 99% in Example 1 to 38% in Comparative Example 1. When the pH is adjusted first in Comparative Example 2 and the pH is not controlled during the reaction, the hydroxylamine removal rate is reduced to 52%. When the pH is too low in Comparative Example 3, the hydroxylamine removal rate is reduced to 42%.

[0073] In summary, the present invention achieves the technical effect of efficiently removing hydroxylamine in wastewater at low acid consumption through the synergistic effect of transition metal catalyst and pH adjustment.

[0074] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for treating hydroxylamine-containing waste liquid, characterized in that: The processing method comprises: (1) mixing a transition metal catalyst with a hydroxylamine-containing waste liquid to obtain a mixed liquid and subjecting it to a self-decomposition reaction; (2) maintaining the pH of the mixed solution at 9.0-10.5 during the autolysis reaction; (3) After the autolysis reaction is completed, solid-liquid separation is performed to obtain dehydroxylamine waste liquid.

2. The processing method according to claim 1, characterized in that The transition metal catalyst includes any one of a transition metal element, a transition metal oxide and a transition metal salt, or a combination of at least two of them.

3. The processing method according to claim 2, characterized in that The transition metal element includes any one of iron, copper, cobalt and nickel, or a combination of at least two of them.

4. The processing method according to claim 2, characterized in that The transition metal oxide includes any one of iron oxide, copper oxide, cobalt oxide and nickel oxide, or a combination of at least two thereof.

5. The processing method according to claim 2, characterized in that: The transition metal salt includes any one or a combination of at least two of ferric chloride, cupric chloride, cobalt chloride, nickel chloride, ferric sulfate, ferrous sulfate, cupric sulfate, cobalt sulfate and nickel sulfate, preferably ferrous sulfate or cupric chloride.

6. The processing method according to any one of claims 1 to 5, characterized in that: The hydroxylamine content of the hydroxylamine-containing waste liquid is 2%-15% by mass; Preferably, the pH value of the hydroxylamine-containing waste liquid is 10-12.

7. The processing method according to any one of claims 1 to 6, characterized in that: The amount of the transition metal catalyst added is 3%-6% of the hydroxylamine-containing waste liquid.

8. The processing method according to any one of claims 1 to 7, characterized in that: The self-decomposition reaction time is 4-6h; Preferably, stirring is performed during the autodecomposition reaction; Preferably, no heating is performed during the autolysis reaction.

9. The processing method according to any one of claims 1 to 8, characterized in that: During the autodecomposition reaction, a pH regulator is continuously added to maintain the pH of the mixed solution; Preferably, the pH adjuster comprises sulfuric acid.

10. The processing method according to any one of claims 1 to 9, characterized in that: The processing method comprises: (1) mixing a transition metal catalyst with a hydroxylamine-containing waste liquid having a hydroxylamine content of 2% to 15% by mass to obtain a mixed liquid to initiate a self-decomposition reaction, wherein the amount of the transition metal catalyst added is 3% to 6% of the hydroxylamine-containing waste liquid; (2) During the autolysis reaction, sulfuric acid was continuously added to adjust the pH of the mixture to 9.0-10.5 and stirred to carry out the autolysis reaction for 4-6 hours; (3) After the autolysis reaction is completed, solid-liquid separation is performed to obtain dehydroxylamine waste liquid.

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