TW202210409A - Method for removing hydrogen peroxide from sulfuric acid - Google Patents

Abstract

A method for removing hydrogen peroxide from sulfuric acid comprises the following steps: Add catalysts into the feedstock, perform cooling, remove metal in sulfuric acid, and obtain high purity dilute sulfuric acid after filtration. The present invention eventually generates metal sulfide and high purity dilute sulfuric acid (completely without hydrogen peroxide) whereas both materials can be recycled and re-used. Therefore, the effect of recycle and reuse of polybasic products can be achieved. The present invention will not produce chloride ions and thus reduce the additional risk that the equipment may be corroded. Furthermore, the present invention can completely remove hydrogen peroxide from sulfuric acid and produce high purity dilute sulfuric acid. High purity dilute sulfuric acid can directly serve as the raw material for various processing chemical reactions to achieve the goal of highly purifying waste sulfuric acid as well as recycle and reuse with high efficiency. Thus, the sustainable utilization rate of waste sulfuric acid is enhanced.

Description

Method for removing hydrogen peroxide in sulfuric acid

The present invention relates to a method for removing hydrogen peroxide in sulfuric acid, in particular, it refers to a method for removing hydrogen peroxide in sulfuric acid which can make waste sulfuric acid with hydrogen peroxide to be more fully reused.

The wafer foundry in the semiconductor industry cleans the surface of silicon wafers with high _- purity sulfuric _acid during the wafer manufacturing process, mainly for cleaning silicon wafers after photoresist removal _{. 2} ), forming a strong oxidant, and oxidatively decomposes the organic matter in the wafer into CO ₂ and H ₂ O, and finally produces the so-called waste sulfuric acid; and the main component in the waste sulfuric acid is the concentration of sulfuric acid (H ₂ SO ₄ ) About 40%-85%, hydrogen peroxide (H ₂ O ₂ ) about 4% to 8%, and the rest are mainly water.

However, there are too many impurities in the waste sulfuric acid, especially the hydrogen peroxide (H ₂ O ₂ ) contained in the waste sulfuric acid is a strong oxidant, so it will limit the reusability of the sulfuric acid (H ₂ SO ₄ ), so the waste sulfuric acid cannot be directly returned to the wafer. The process is reused; the foundry's reuse of waste sulfuric acid treatment usually removes the hydrogen peroxide (H ₂ O ₂ ) in the waste sulfuric acid and generates other reused products as a treatment method for waste sulfuric acid.

There are many known methods for removing hydrogen peroxide in waste sulfuric acid. At present, the following two are most widely used. One method is to add hydrochloric acid (HCl) to waste sulfuric acid for chemical reaction. The main chemical reaction is: H ₂ O ₂ + 2HCl→ Cl _2(g) + 2H ₂ O; another method is to add activated carbon or enzymes to waste sulfuric acid, and then achieve the effect of decomposing hydrogen peroxide (H ₂ O ₂ ).

However, the conventional method for removing hydrogen peroxide in waste sulfuric acid has the following deficiencies:

1. Adding hydrochloric acid (HCl) to waste sulfuric acid, although part of hydrogen peroxide (H ₂ O ₂ ) in waste sulfuric acid can be removed, the final product will produce dilute sulfuric acid (H ₂ SO ₄ ) containing chloride ions (Cl ^- ), Chloride ions (Cl ^- ) can cause problems in product processing, and process equipment may be easily corroded, resulting in poor quality of processed products.

2. Adding enzymes to waste sulfuric acid can remove part of hydrogen peroxide in waste sulfuric acid, but its removal rate is not high, and the chemical reaction time is very long, which finally leads to a lot of increase in treatment costs.

In view of this, the applicant of this case, based on his years of experience in research and development in related fields, conducted in-depth discussions on the aforementioned deficiencies, and actively sought solutions based on the aforementioned needs. invention.

The main purpose of the present invention is a method for removing hydrogen peroxide in sulfuric acid, and further speaking, a method for removing hydrogen peroxide in sulfuric acid by making waste sulfuric acid with hydrogen peroxide to be more fully reused.

In order to achieve the above-mentioned purpose, the present invention removes the method for hydrogen peroxide in sulfuric acid, and includes the following steps S1～S5:

S1 feeding step: take sulfuric acid (H ₂ SO ₄ ) containing hydrogen peroxide (H ₂ O ₂ ) 0.1% to 10% as raw material feed;

S2 adding catalyst step: adding metal or metal oxide as catalyst to carry out chemical reaction to remove hydrogen peroxide (H ₂ O ₂ );

S3 cooling step: sulfuric acid (H ₂ SO ₄ ) chemically reacts with the catalyst to generate exothermic phenomenon, and temperature control is performed using cooling equipment;

S4 metal removal step: sulfuric acid (H ₂ SO ₄ ) chemically reacts with the catalyst to generate sulfuric acid (H ₂ SO ₄ ) containing metal ions, so divalent sulfur (S ^2- ) substances are added to chemically react the metal to generate metal sulfide;

S5 Filtration step: The product generated by the reaction is filtered and separated, and high-purity metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be separated.

Among them, activated carbon can be added after the filtration step S5 for deodorization, so that the product generated after filtration can reduce the peculiar smell, so as to maintain the product quality.

Among them, when the divalent sulfur (S ^2- ) substance in the metal removal step of S4 is input for chemical reaction, the input dose can be controlled by the ORP (redox potential) control device; while the divalent sulfur (S ^2- ) substance It can be divalent sulfur (S ^2- ) substances such as sodium hydrosulfide (NaHS), sodium sulfide (Na ₂ S), organic sulfur or hydrogen sulfide (H ₂ S), the supply of the divalent sulfur (S ^2- ) substances The source can be supplied through commercially available divalent sulfur (S ^2- ) substances to ensure that the sulfuric acid (H ₂ SO ₄ ) containing metal ions has a stable and appropriate source of divalent sulfur (S ^2- ) substances, thereby To achieve the purpose of stably carrying out the chemical reaction of removing metal ions.

By the method for removing hydrogen peroxide in sulfuric acid of the present invention, high-purity metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ) can finally be generated, and the chemical reaction time can be passed through the added catalyst dosage, cooling equipment, divalent sulfur (S ^2- ) Substance dosage control, so chemical reaction can be carried out efficiently, and the two final products can be used as raw materials for other processing processes or used for other purposes, thus improving the sustainable utilization rate of products after process processing, especially The present invention finally produces high-purity dilute sulfuric acid (H ₂ SO ₄ ) that can be directly processed by many chemical reactions. Therefore, the waste sulfuric acid originally containing hydrogen peroxide can be used in a wider range of applications after being treated by the present invention.

In order to allow a more detailed understanding of the purpose, effect, features and structure of the present invention, preferred embodiments are given and described in conjunction with the drawings as follows.

First, please refer to Fig. 1 and Fig. 2 at the same time, Fig. 1 is a flow chart of a method for removing hydrogen peroxide in sulfuric acid according to a preferred embodiment of the present invention, and Fig. 2 is a schematic implementation diagram of a method for removing hydrogen peroxide in sulfuric acid according to a preferred embodiment of the present invention.

The method 1 of removing hydrogen peroxide in sulfuric acid according to a preferred embodiment of the present invention includes the following steps S1 to S5 (as shown in FIG. 1 ), and this embodiment is illustrated by taking copper oxide (CuO) as an example (as shown in FIG. 1 ) 2):

S1 feeding step: as shown in S101 in Figure 2, using sulfuric acid (H ₂ SO ₄ ) containing 0.1% to 10% of hydrogen peroxide (H ₂ O ₂ ) as raw material feed;

S2 adding catalyst step: adding metal or metal compound as a catalyst for chemical reaction to remove hydrogen peroxide (H ₂ O ₂ ); the catalyst can be copper or copper compounds, such as copper oxide (CuO), hydrogen Copper oxide (Cu(OH) ₂ ), copper carbonate (‎CuCO ₃ ), copper sulfate (‎CuSO ₄ ), metal copper (Cu), etc.; the catalyst can also be silver (Ag) or silver compounds; The catalyst can also be mercury (Hg) or mercury compounds, and among them, copper oxide (CuO) is the best catalyst, so this embodiment is described with copper oxide (CuO) as the catalyst;

As shown in S201 and S202 in Figure 2, when sulfuric acid (H ₂ SO ₄ ) containing hydrogen peroxide (H ₂ O ₂ ) is added with copper oxide (CuO) as a catalyst, the hydrogen peroxide (H ₂ O ₂ ) can be decomposed. The chemical reaction is accelerated and copper sulfate (CuSO ₄ ) is formed, and the dose of copper oxide (CuO) can be adjusted according to the proportional concentration of hydrogen peroxide (H ₂ O ₂ ) in sulfuric acid (H ₂ SO ₄ ), so that hydrogen peroxide (H ₂ O ₂ ) can be completely decomposed and removed without producing unnecessary products, mainly only metal ions and sulfuric acid (H ₂ SO ₄ ).

The chemical reaction formula is mainly as follows:

CuO _(s) + H ₂ SO _4(l) → CuSO _4(l) + H ₂ O _(l)

2H₂ O_{2 ( l )} ^Cu2+ _→ 2H₂ O_{( l )} + O_{2 ( g )}

S3 cooling step: the chemical reaction between sulfuric acid (H ₂ SO ₄ ) and the catalyst produces exothermic phenomenon, and temperature control equipment is used for temperature control; since the chemical reaction between sulfuric acid (H ₂ SO ₄ ) and the catalyst is a chain reaction, the reaction process The temperature will continue to rise until the reactants are completely reacted and exhausted. Therefore, if the reaction temperature is not controlled, when the temperature is too high, the equipment may be damaged or even the danger of explosion may occur. It is better to maintain at 60℃~90℃ to keep the temperature stable and make the chemical reaction proceed stably.

S4 metal removal step: sulfuric acid (H ₂ SO ₄ ) chemically reacts with the catalyst to generate sulfuric acid (H ₂ SO ₄ ) containing metal ions, so divalent sulfur (S ^2- ) substances are added to chemically react the metal to generate metal Sulfide; as shown in S401 in Figure 2, using copper oxide (CuO) as a catalyst and hydrogen sulfide (H ₂ S) gas as a divalent sulfur (S ^2- ) substance as an example, sulfuric acid (H ₂ SO ₄ ) After the reaction, copper sulfate (CuSO ₄ ) is generated, and the hydrogen sulfide (H ₂ S) gas can chemically react with copper sulfate (CuSO ₄ ) to generate copper sulfide (CuS), and this chemical reaction is used to remove copper sulfate (CuSO 4 ) ₄ ) in copper ions (Cu ²⁺ ).

The chemical reaction formula is mainly as follows:

H ₂ S _(g) + CuSO _4(l) → CuS _(s) ↓+ H ₂ SO _4(l)

S5 filtration step: as shown in S501 and S502 in Figure 2, the product generated by the reaction is filtered and separated, and metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be separated; the product copper sulfate generated by the reaction is used. (CuSO ₄ ) as an example, copper sulfate (CuSO ₄ ) reacts with hydrogen sulfide (H ₂ S) gas to generate high-purity copper sulfide (CuS) and high-purity dilute sulfuric acid (H ₂ SO ₄ ). The final product of this chemical reaction is pure Finally, the high-purity copper sulfide (CuS) and the high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be collected and reused separately. The aforementioned high-purity copper sulfide (CuS) can be used as a preparation for analysis experiments and other purposes, while the high-purity copper sulfide (CuS) can be used for Dilute sulfuric acid (H ₂ SO ₄ ) can directly provide chemical reaction raw materials for various processing processes, resulting in the effect of diversified recovery and reuse (S501 and S502 in Figure 2).

Among them, activated carbon can be added to remove odor after the filtration step S5, so that the product generated after filtration can reduce the peculiar smell, so as to maintain the product quality.

Among them, when the divalent sulfur (S ^2- ) substance in the metal removal step of S4 is input for chemical reaction, the input dose can be controlled by the ORP (redox potential) control device; while the divalent sulfur (S ^2- ) substance It can be divalent sulfur (S ^2- ) such as sodium hydrosulfide (NaHS), sodium sulfide (Na ₂ S), organic sulfur or hydrogen sulfide (H ₂ S), or through commercially available divalent sulfur (S ² ). ^- ) substance is used as a source to ensure that the sulfuric acid (H ₂ SO ₄ ) containing metal ions has a stable and appropriate source of divalent sulfur (S ^2- ), so as to achieve the purpose of stably carrying out the chemical reaction of removing metal ions (this The examples take copper sulfate (CuSO ₄ ) as an example).

By the method for removing hydrogen peroxide in sulfuric acid of the present invention, high-purity metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be finally generated, and chloride ions (Cl ^- ) will not be generated, but both products can be generated as _The raw materials of other processing processes or other purposes can be used to improve the sustainable utilization rate of the products after processing _. The waste sulfuric acid originally containing hydrogen peroxide can be used in a wider range after being treated by the present invention.

Please refer to Fig. 3, Fig. ₃ is the inspection report of the method for removing _hydrogen peroxide in sulfuric acid according to the preferred embodiment of the present invention; The hydrogen peroxide has been almost completely removed, so the finally generated high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be directly recovered and used again.

In summary, the present invention removes the method for hydrogen peroxide in sulfuric acid, and its advantages are:

1. Generate high-purity dilute sulfuric acid (H ₂ SO ₄ ) for high-proportion recovery and reuse: the present invention can finally generate high-purity metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ), and both main products can be It is recycled again to improve the sustainable utilization rate of the product after the process, especially the present invention finally generates high-purity dilute sulfuric acid (H ₂ SO ₄ ) that can be directly used for many chemical reaction processing applications, so that the original containing hydrogen peroxide (H ₂ O ₂ ) The waste sulfuric acid treated by the present invention has a wider range of uses.

2. Products of multiple recycling and reuse: the present invention will finally generate two or more recyclable products from waste sulfuric acid containing hydrogen peroxide (H ₂ O ₂ ), such as high-purity copper sulfide (CuS), high-purity dilute sulfuric acid (H 2 O 2 ). ₂ SO ₄ ), which can provide more diversified recycling.

3. Because copper ions are used as catalysts, other chloride ions will not be generated: the present invention uses copper ions as catalysts, and the final main products are metal sulfides and high-purity dilute sulfuric acid, so chloride ions will not be generated, so the equipment can be maintained. Less susceptible to corrosion to avoid unnecessary process risks.

Therefore, the present invention has excellent progress and practicability among similar products, and at the same time, after searching domestic and foreign technical data and documents about such structures, it is true that no identical or similar structures exist before the application in this case. Therefore, this case The patent requirements for "creativeness", "suitability for industrial utilization" and "progressiveness" should be met, and the application should be filed in accordance with the law.

However, the above are only preferred embodiments of the present invention, and any other equivalent structural changes made by applying the description of the present invention and the scope of the patent application should be included in the scope of the patent application of the present invention.

1: Method for removing hydrogen peroxide in sulfuric acid S1: Feeding step S2: Add catalyst step S3: cooling step S4: Metal removal step S5: Filtration step S101: raw material (sulfuric acid containing hydrogen peroxide) S201: Add catalyst (copper oxide) S202: Removal of hydrogen peroxide to form copper sulfate S401: Adding hydrogen sulfide to generate copper sulfide and high-purity sulfuric acid S501: Collect copper sulfide for reuse S502: Collect high-purity sulfuric acid for reuse

Fig. 1: the flow chart of the method for removing hydrogen peroxide in sulfuric acid in the preferred embodiment of the present invention; Fig. 2: the implementation schematic diagram of the method for removing hydrogen peroxide in sulfuric acid in the preferred embodiment of the present invention; Fig. 3: The inspection report of the method for removing hydrogen peroxide in sulfuric acid in the preferred embodiment of the present invention.

without.

1: Method for removing hydrogen peroxide in sulfuric acid

S1: Feeding step

S2: Add catalyst step

S3: cooling step

S4: Metal removal step

S5: Filtering step

Claims (10)

A method for removing hydrogen peroxide in sulfuric acid, comprising the following steps S1~S4: S1 feeding step: using sulfuric acid containing hydrogen peroxide (H ₂ O ₂ ) 0.1%~10% as raw material feed; S2 adding catalyst step: adding Metals or metal compounds are used as catalysts for chemical reaction to remove hydrogen peroxide (H ₂ O ₂ ); S3 cooling step: sulfuric acid (H ₂ SO ₄ ) chemically reacts with catalysts to generate exothermic phenomena, and temperature control equipment is used for temperature control ; S4 removes metal step: sulfuric acid (H ₂ SO ₄ ) and catalyst are chemically reacted to generate sulfuric acid containing metal ions, so adding divalent sulfur (S ^2- ) substance to chemically react metal to generate metal sulfide; S5 filtration Step: filter and separate the product generated by the reaction, and metal sulfide and high-purity dilute sulfuric acid (H ₂ SO ₄ ) can be separated. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is to add copper (Cu) as a catalyst for chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is to add a copper compound as a catalyst to carry out a chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is adding silver (Ag) as a catalyst to carry out a chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is to add a silver compound as a catalyst to carry out a chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is to add mercury (Hg) as a catalyst for chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the step of adding a catalyst to S2 is to add a mercury compound as a catalyst to carry out a chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein, after the filtering step S5, activated carbon can be added for deodorization. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the divalent sulfur (S ^2- ) substance in the metal removal step S4 is controlled by an ORP (redox potential) control device to control its input dose for chemical reaction. The method for removing hydrogen peroxide in sulfuric acid according to claim 1, wherein the supply source of divalent sulfur (S ^2- ) material in the metal removal step of S4 can be directly used as a source through commercially available divalent sulfur (S ^2- ) material.

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