Apparatus and method for recycling sulfuric acid

Abstract

To provide a novel method for treating waste sulfuric acid and improving the quality of recycled sulfuric acid.SOLUTION: An apparatus for recycling sulfuric acid is provided. A container has an internal space. An inlet is located on a first side of the container and introduces a liquid containing sulfuric acid and hydrogen peroxide. An outlet is located on a second side of the container and discharges the treated liquid from the container. The first and second sides face each other. An infrared lamp and an ultraviolet lamp are located in the inner space of the container and contact the liquid. Infrared light emitted from the infrared lamp and ultraviolet light emitted from the ultraviolet lamp decompose hydrogen peroxide in the liquid into water and oxygen. Infrared light heats the liquid and oxygen is discharged from an air hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an apparatus and method for recycling sulfuric acid. [Background technology]

[0002] In semiconductor manufacturing processes, electronic-grade sulfuric acid is used to prepare Caro's acid solution to clean wafers, and waste sulfuric acid from this cleaning process is the largest process waste liquid. In 2021, the amount of waste sulfuric acid generated reached 365,000 tons. As the semiconductor industry expands, the amount of waste sulfuric acid (which is difficult to remove) is expected to reach 516,000 tons. Waste sulfuric acid, which consists of more than 50 wt% sulfuric acid and 1 wt% to 5 wt% hydrogen peroxide, cannot be directly reused due to its strong oxidizing properties. For the main contaminants in waste sulfuric acid such as hydrogen peroxide, the current treatment is to add hydrochloric acid as a catalyst to decompose hydrogen peroxide until it is less than 50 mg / L. However, this process produces harmful substances such as chlorine gas and leaves chloride ions in the purified sulfuric acid. Therefore, this process is not the optimal purification method. In addition, commercial enzymes can be added to remove hydrogen peroxide from waste sulfuric acid, but it is expensive and not very effective. Furthermore, enzymes have problems such as chemical residues and changes in the quality of the acid, making it difficult to use the acid without removing the enzymes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2019 / 0174802A1 [Patent Document 2] Taiwan Patent Application Publication No. TW559940B Summary of the Invention [Problem to be solved by the invention]

[0004] New methods are needed to treat waste sulfuric acid and to improve the quality of the recycled sulfuric acid. [Means for solving the problem]

[0005] An embodiment of the present disclosure provides an apparatus for recycling sulfuric acid, including a container, an inlet, an outlet, an infrared (IR) lamp, an ultraviolet (UV) lamp, a bracket, and a lid. The container has an interior space. The inlet is located on a first side of the container. The inlet is used to introduce a liquid containing sulfuric acid and hydrogen peroxide. The liquid can be introduced into the container from the inlet via a pump. The outlet is located on a second side of the container. The outlet is used to discharge the treated liquid from the container. The first side and the second side are opposed. The infrared lamp is located in the interior space of the container. The infrared lamp is adapted to contact the liquid. The ultraviolet lamp is located in the interior space of the container. The ultraviolet lamp is adapted to contact the liquid. The bracket is located in the interior space of the container. The bracket connects the infrared lamp and the ultraviolet lamp. The lid covers an upper side of the container. The lid has an air hole. The air hole can be connected to an exhaust device. Infrared light emitted from the infrared lamp and ultraviolet light emitted from the ultraviolet lamp decompose hydrogen peroxide in the liquid into water and oxygen. The infrared heats the liquid and oxygen is expelled through the air hole. The liquid is preferably heated to between 90°C and 130°C.

[0006] In some embodiments, the device further comprises a three-way valve connected to the outlet and used to exhaust oxygen.

[0007] In some embodiments, the infrared radiation has a wavelength of 1500 nm to 6500 nm.

[0008] In some embodiments, the wavelength of the ultraviolet light is between 230 nm and 275 nm.

[0009] In some embodiments, the energy density of each of the infrared and ultraviolet rays is 0.1 W / cm 2 from 16 W / cm 2It is.

[0010] In some embodiments, the ratio of infrared to ultraviolet energy densities is between 4:1 and 20:1.

[0011] In some embodiments, the apparatus further includes other infrared lamps and other ultraviolet lamps, wherein the ratio of the total cross-sectional area of ​​the infrared lamps to the cross-sectional area of ​​the container is from 1:100 to 5:100, and the ratio of the total cross-sectional area of ​​the ultraviolet lamps to the cross-sectional area of ​​the container is from 1:100 to 5:100.

[0012] In some embodiments, the infrared lamps are arranged in a cross-section of the container to form a first circle, and the ultraviolet lamps are arranged in a cross-section of the container to form a second circle, the first and second circles being concentric, and the diameter of the first circle being greater than the diameter of the second circle.

[0013] In some embodiments, the flow rate of the liquid introduced through the inlet is between 0.5 m / hr and 3 m / hr.

[0014] In some embodiments, the sulfuric acid concentration of the liquid is between 50 wt% and 70 wt%.

[0015] In some embodiments, the hydrogen peroxide concentration of the liquid is between 10,000 mg / L and 60,000 mg / L, and the hydrogen peroxide concentration of the treated liquid is 50 mg / L or less.

[0016] In some embodiments, the sidewall of the container has a textured structure.

[0017] One embodiment of the present disclosure provides a method for recycling sulfuric acid, comprising the steps of: providing a liquid containing sulfuric acid and hydrogen peroxide in a container; decomposing the hydrogen peroxide in the liquid into water and oxygen using infrared and ultraviolet light, where the liquid is heated to 90°C to 130°C by the infrared light; and collecting the treated liquid.

[0018] In some embodiments, the method further comprises removing oxygen upon decomposition of hydrogen peroxide into water and oxygen.

[0019] In some embodiments, the infrared radiation has a wavelength of 1500 nm to 6500 nm.

[0020] In some embodiments, the wavelength of the ultraviolet light is between 230 nm and 275 nm.

[0021] In some embodiments, the energy density of each of the infrared and ultraviolet rays is 0.1 W / cm 2 from 16 W / cm 2 It is.

[0022] In some embodiments, the ratio of infrared to ultraviolet energy densities is between 4:1 and 20:1.

[0023] In some embodiments, the sulfuric acid concentration of the liquid is between 50 wt% and 70 wt%.

[0024] In some embodiments, the hydrogen peroxide concentration of the liquid is between 10,000 mg / L and 60,000 mg / L, and the hydrogen peroxide concentration of the treated liquid is 50 mg / L or less. Effect of the Invention

[0025] The present disclosure combines ultraviolet and infrared light to effectively increase the reaction rate (eg, increase the efficiency of decomposing hydrogen peroxide in the same treatment time).

[0026] Detailed description will be given in the following embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0027] The present disclosure can be more fully understood by reading the following detailed description and embodiments in conjunction with the accompanying drawings. [Figure 1]FIG. 1 illustrates a perspective view of an apparatus for recycling sulfuric acid according to some embodiments. [Diagram 2] 1 illustrates several embodiments of multiple vessels connected in series. [Diagram 3] 2 shows a cross-sectional view of the bracket, infrared lamp, and ultraviolet lamp in the apparatus for recycling sulfuric acid of FIG. 1 along the cross section a-a'. [Figure 4] 2 shows a cross-sectional view of an arrangement of infrared and ultraviolet lamps in the apparatus for recycling sulfuric acid of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be apparent that one or more embodiments may be practiced without these specific details. Additionally, for purposes of simplicity in the drawings, well-known structures and devices are generally shown.

[0029] An embodiment of the present disclosure provides an apparatus 100 for recycling sulfuric acid, as shown in FIG. 1. The apparatus 100 includes a container 101 having an internal space. In some embodiments, the container 101 is made of poly(tetrafluoroethene) (PTFE) or other suitable material. PTFE is resistant to acid corrosion and heat, and has a certain angle of reflecting infrared and ultraviolet light, which is advantageous for processing liquids as described below. The container 101 in FIG. 1 is cylindrical, but is not limited thereto. Those skilled in the art can adopt any reasonable shape of the container without departing from the scope of the present disclosure. For example, the cross section of the container 101 may be not only circular, but also square, rectangular, hexagonal, elliptical, or any other shape, as long as it is convenient for installation and operation. In addition, the volume of the container 101 may be 1 L to 20 L, but is not limited thereto. If the volume of the container 101 is too small, the amount of liquid that can be processed in a certain time is insufficient. If the volume of the container 101 is too large, it is difficult to assemble and clean.

[0030] The apparatus 100 also includes an inlet 103 located on a first side of the vessel 101 for introducing a liquid containing sulfuric acid and hydrogen peroxide. The liquid can be introduced into the vessel 101 from the inlet 103 via a pump. The inlet 103 can be connected via a conduit to a process chamber (e.g., an etching chamber or a cleaning chamber, not shown) that produces the liquid. In general, the liquid produced by the process chamber may contain a small amount of solid impurities. The solid impurities can be removed by a filtration net. The liquid is then introduced into the vessel 101. The conduit connecting the process chamber and the inlet 103 can be made of PTFE or polypropylene (PP), depending on the temperature of the liquid produced by the process chamber. If the temperature of the liquid is high (e.g., higher than 80° C.), the conduit can be made of heat-resistant PTFE. If the temperature of the liquid is low (e.g., room temperature), the conduit can be made of PP, which can reduce costs.

[0031] The device 100 also includes an outlet 105 located on the second side of the container 101 for discharging the treated liquid from the container 101, the first side facing the second side. The outlet 105 may be connected to a collection tank (not shown) or to the inlet 103 of another device 100. For example, as shown in FIG. 2, multiple devices 100 may be connected in series, and the outlet 105 of each device 100 may be connected to the inlet 103 of the next device 100 via a pipe. In this way, the amount of liquid that can be treated per unit time can be increased. Using multiple devices 100 with small volumes connected in series (rather than a single device with a large volume) is advantageous for cleaning and maintenance in practical use. For example, after replacing one of the multiple devices 100 connected in series with a new device 100, the liquid can be continued to be processed, and the replaced device 100 can be cleaned and maintained at the same time. In contrast, when cleaning and maintaining a single device with a large volume, the processing of the liquid must be stopped. Even if a separate single device with a larger volume is prepared as a backup, the cost of assembling and disassembling it is still higher than that of the device 100 with a smaller volume connected in series. In the state where the device 100 is installed, for example, the first side is the upper side of the container 101, and the second side is the lower side of the container 101. The inlet 103 is preferably provided at a position lower than the outlet 105. The inlet 103 is preferably provided at a position close to the lower side of the container 101, and the outlet 105 is preferably provided at a position close to the upper side of the container 101. The liquid that flows into the container 101 from the inlet 103 located at the lower side flows toward the outlet 105 located at the upper side, and in the container 101, decomposition of hydrogen peroxide in the liquid into water and oxygen is promoted using infrared and ultraviolet rays. The oxygen is discharged to the outside of the device 100 through an air hole provided in the upper lid. The liquid treated in the container 101 is discharged to the outside of the device 100 through the outlet 105 located at the upper side. The outlet 105 may be connected to the inlet 103 of another device 100 in a liquid-flowable manner, so that the treated liquid is further treated by the other device 100.

[0032] The apparatus 100 also includes an infrared lamp 107 located in the interior space of the vessel 101 and in contact with the liquid. It is noted that the efficiency of the infrared lamp 107 may be increased because the infrared lamp 107 is not mounted on the sidewall of the vessel 101. The tube of the infrared lamp 107 is made of quartz, which avoids the problem of acid corrosion of the liquid.

[0033] The device 100 also includes an ultraviolet lamp 109 located in the interior space of the vessel 101 and in contact with the liquid. It is noted that the ultraviolet lamp 109 is not installed on the sidewall of the vessel 101, which may increase the efficiency of the ultraviolet lamp 109. The tube of the ultraviolet lamp 109 is made of quartz, which avoids the problem of acid corrosion of the liquid. It is noted that the liquid volume tends not to be higher than the outlet 105, since an excessively high liquid volume will negatively affect the life of the infrared lamp 107 and the ultraviolet lamp 109.

[0034] The apparatus 100 also includes a bracket 111 located in the inner space of the container 101 for connecting the infrared lamp 107 and the ultraviolet lamp 109. The structure of the bracket 111 is as shown in the cross-sectional view of FIG. 3. FIG. 3 shows a cross-sectional view of the bracket 111, the infrared lamp 107, and the ultraviolet lamp 109 in the apparatus 100 for recycling sulfuric acid of FIG. 1 along the cross section a-a'. In FIG. 3, the bracket 111 has a cross shape in a circular frame to increase the degree of support, and the infrared lamp 107 and the ultraviolet lamp 109 are located at the end points of the cross shape, respectively. It should be understood that FIG. 3 is merely an example and does not limit the scope of the present disclosure. Alternatively, the frame of the bracket 111 may be other shapes, such as a square, a hexagon, or another suitable shape, and the cross shape may be changed to other patterns, such as a star shape (e.g., *). In some embodiments, the brackets 111 may be spaced apart to provide a higher degree of support, and the spacing between adjacent brackets 111 and the pattern of brackets 111 may be the same or different. Take Fig. 3 as an example, the pattern of brackets 111 has a turbulent effect that helps to uniformly mix the liquid flowing from inlet 103 to outlet 105. In addition, as shown in Fig. 1, the sidewall of the container 101 may be flat or have a certain uneven structure (not shown) to further enhance the turbulent effect.

[0035] 1, the apparatus 100 also includes a lid 115 that covers the top of the container 101 and has an air hole 117, which can be connected to an exhaust system (not shown). The lamp bases of the infrared lamp 107 and the ultraviolet lamp 109 protrude from the lid 115 and connect to a power source, and a bracket 119 may optionally be disposed on the lid 115 to support the ends of the infrared lamp 107 and the ultraviolet lamp 109.

[0036] In some embodiments, the infrared light emitted from the infrared lamp 107 and the ultraviolet light emitted from the ultraviolet lamp 109 decompose the hydrogen peroxide in the liquid into water and oxygen, the infrared light heats the liquid, and the oxygen is exhausted through the air hole 117. The liquid is preferably heated to 90°C to 130°C. If the liquid temperature is too low, the efficiency of decomposing hydrogen peroxide is insufficient. If the liquid temperature is too high, a large amount of oxygen is generated quickly and cannot be easily controlled. The infrared light not only heats the liquid, but also promotes the ultraviolet light to decompose the hydrogen peroxide. If the infrared lamp 107 is not adopted (for example, only the ultraviolet lamp 109 is adopted and the liquid is heated by another heating device such as a hot plate), the effect of decomposing hydrogen peroxide is reduced.

[0037] The sulfuric acid recycling apparatus 100 shown in FIG. 2 may further include a three-way valve 113 connected to the outlet 105 and used to exhaust oxygen. The three-way valve 113 may be disposed between the outlet 105 of the container 101 and a collection tank (not shown), or between the outlet 105 of the container 101 and the inlet 103 of the next container 101. The oxygen generated by decomposing hydrogen peroxide can be exhausted from the above-mentioned air hole 117 and the three-way valve 113. The oxygen does not accumulate in the container 101 and does not adversely affect the step of treating the liquid. The three-way valve 113 may also be connected to the outlet 105 of the container 101 and the inlet 103 (or collection tank) of the next container 101 through a pipe. In addition, the three-way valve 113 may be connected to an exhaust device (not shown) like the above-mentioned air hole 117.

[0038] In some embodiments, the wavelength of the infrared ray is 1500 nm to 6500 nm, which corresponds to the wavelength of the main absorption peak of hydrogen peroxide, such as 2800 nm to 2900 nm, 3500 nm to 3600 nm, and 6000 nm to 6500 nm. If the wavelength of the infrared ray is not within the above range, the decomposition effect of hydrogen peroxide cannot be effectively improved.

[0039] In some embodiments, the wavelength of the ultraviolet light is from 230 nm to 275 nm. If the wavelength of the ultraviolet light is not within the above range, hydrogen peroxide cannot be effectively decomposed.

[0040] In some embodiments, the energy density of each of the infrared and ultraviolet rays is 0.1 W / cm 2 from 16 W / cm 2 If the energy density of infrared or ultraviolet light is too low, hydrogen peroxide cannot be effectively decomposed. If the energy density of infrared or ultraviolet light is too high, it becomes difficult to control the reaction temperature, and sulfuric acid or hydrogen peroxide will boil, increasing the risk of operation.

[0041] In some embodiments, the ratio of infrared and ultraviolet energy density is 4:1 to 20:1. If the ratio is too low, the reaction rate cannot be increased, and the treatment effect is reduced. If the ratio is too high, it is difficult to control the reaction temperature, and sulfuric acid or hydrogen peroxide will boil, increasing the risk of operation.

[0042] In some embodiments, the device further includes another infrared lamp 107 and another ultraviolet lamp 109, and the ratio of the total cross-sectional area of ​​the infrared lamp 107 to the cross-sectional area of ​​the container 101 is 1:100 to 5:100, and the ratio of the total cross-sectional area of ​​the ultraviolet lamp 109 to the cross-sectional area of ​​the container 101 is 1:100 to 5:100. If the total cross-sectional area of ​​the infrared lamp 107 is too small, the heating time will be too long and the desired reaction temperature cannot be reached. If the total cross-sectional area of ​​the infrared lamp 107 is too large, it will be difficult to control the reaction temperature, and sulfuric acid or hydrogen peroxide will boil, increasing the risk of operation.

[0043] In some embodiments, as shown in FIG. 4, the infrared lamps 107 are arranged in a cross section of the vessel 101 to form a first circle, and the ultraviolet lamps 109 are arranged in a cross section of the vessel 101 to form a second circle, the first circle and the second circle are concentric, and the diameter of the first circle is larger than the diameter of the second circle. FIG. 4 shows a cross section of the arrangement of the infrared lamps and the ultraviolet lamps in the apparatus for recycling sulfuric acid of FIG. 1. It should be understood that FIG. 4 only shows a cross section of the infrared lamps 107 and the ultraviolet lamps (e.g., the bracket 111 is not shown in this cross section). In some embodiments, the bracket 111 may be disposed between the infrared lamps 107 and the ultraviolet lamps 109 and fixed in the vessel 101. FIG. 4 is merely for illustrative purposes, not for limiting the scope of the present disclosure. Those skilled in the art can arrange the multiple infrared lamps 107 and the multiple ultraviolet lamps 109 in any manner. For example, the infrared lamps 107 and the ultraviolet lamps 109 may be arranged in a staggered and circular fashion. Regardless of how the infrared lamps 107 and the ultraviolet lamps 109 are arranged, the objective is to achieve the maximum and most uniform infrared and ultraviolet distribution effect with the minimum energy consumption, so that the infrared and ultraviolet light can decompose the hydrogen peroxide in the liquid, and the infrared light can heat the liquid.

[0044] In some embodiments, the flow rate of the liquid introduced from the inlet is 0.5 m / hour to 3 m / hour. If the flow rate of the liquid introduced is too fast, the effect of decomposing hydrogen peroxide will be insufficient. If the flow rate of the liquid introduced is too slow, the uniformity of the liquid will be poor, and the effect of decomposing hydrogen peroxide will be reduced.

[0045] In some embodiments, the sulfuric acid concentration of the liquid is between 50 wt% and 70 wt%. The sulfuric acid is not substantially affected by the above steps. However, due to the decomposition of hydrogen peroxide to form water and oxygen, the sulfuric acid concentration in the treated liquid is slightly reduced (e.g., diluted by the water produced by the decomposition of hydrogen peroxide).

[0046] In some embodiments, the hydrogen peroxide concentration of the liquid is 10000mg / L to 60000mg / L, and the hydrogen peroxide concentration of the treated liquid is 50mg / L or less. The concentration of hydrogen peroxide in the treated liquid may be 40mg / L or less, 30mg / L or less, 10mg / L or less, or even lower than the detection limit of the instrument. In some embodiments, the treated liquid contains a high concentration of sulfuric acid and a very low concentration (or even none) of hydrogen peroxide, so that it can be used in relatively non-precise industries without further purification. In addition, the method does not add any auxiliary agent (e.g., hydrochloric acid) to the liquid, so that the treated liquid is free of any other auxiliary agent and is essentially composed of water and sulfuric acid (and small amounts of hydrogen peroxide, if present).

[0047] In some embodiments, the method for recycling sulfuric acid may include preparing a liquid in a container, the liquid containing sulfuric acid and hydrogen peroxide. The container may be the container 101 of the above-mentioned device 100 or another container. Then, the hydrogen peroxide in the liquid is decomposed into water and oxygen by infrared and ultraviolet light, and the liquid is heated to 90°C to 130°C by infrared light. Finally, the treated liquid is collected. The wavelength and energy density of the infrared and ultraviolet light in this method, as well as the sulfuric acid concentration and hydrogen peroxide concentration in the liquid and the treated liquid, are similar to those described above and will not be repeated here. Therefore, the present disclosure provides a method and device for recycling sulfuric acid, which can decompose hydrogen peroxide in the liquid without adding any auxiliary agent and can effectively recycle sulfuric acid. Compared with the conventional method of adding auxiliary agent, the method of the present disclosure can avoid the generation of harmful gases (e.g., chlorine gas or NOx) in the reaction process and the damage to the treatment equipment and related piping. Moreover, the recycled sulfuric acid recycled in the present disclosure without adding auxiliary agent has high purity and can be directly used in other industries, such as the printed circuit board industry. Compared with the method using only ultraviolet light, the present disclosure combines ultraviolet light and infrared light, which can effectively increase the reaction rate (e.g., the decomposition efficiency of hydrogen peroxide is high in the same treatment time). The method for recycling sulfuric acid is preferably carried out using the device according to the present embodiment.

[0048] In the following, exemplary embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand. The concept of the present invention is not limited to the exemplary embodiments shown herein, but may be embodied in various forms. For clarity, descriptions of known parts will be omitted, and similar reference numerals will denote similar components throughout. EXAMPLES

[0049] In the following examples, the concentration of hydrogen peroxide was analyzed according to the method disclosed by Steller (Spectrophotometric Determination of Hydrogen Peroxide Using Potassium (IV) Oxalate", Analyst, Oct., 105, 950-954 (1980)). For example, an acidic solution of potassium titanium oxalate (0.05M potassium titanium oxalate in 3M H2SO4 solution) was mixed with different amounts of hydrogen peroxide to form different amounts of yellow complexes of tetravalent titanium. These were analyzed by a spectrophotometer, and the absorbance at 400 nm was measured, and then the calibration curve was calibrated. During the analysis, 5 mL of the acidic solution of potassium titanium oxalate, an appropriate amount of sample, and deionized water were mixed uniformly, and the absorbance at 400 nm of the mixture was measured. The concentration of hydrogen peroxide in the sample could be calculated from the absorbance and the calibration curve.

[0050] Comparative Example 1 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 50,000 mg / L hydrogen peroxide was prepared. The mixture was heated to 90°C on a hot plate, and the hydrogen peroxide in the mixture was tracked to obtain a decomposition reaction rate (0.0017 min -1 ), and the decomposition efficiency of hydrogen peroxide (5%) after 1 h of treatment were calculated.

[0051] Comparative Example 2 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 50,000 mg / L hydrogen peroxide was prepared. The mixture was heated to 90°C on a hot plate and irradiated with ultraviolet light (254 nm / 0.22 W / cm 2 ) and tracked the hydrogen peroxide in the mixture to determine the decomposition reaction rate (0.0021 min -1 ), and the decomposition efficiency of hydrogen peroxide after 1 h of treatment (14%) were calculated.

[0052] Comparative Example 3 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 50,000 mg / L hydrogen peroxide was prepared. The mixture was irradiated with infrared light (1500 nm to 6500 nm / 4.21 W / cm 2 ), which heated the mixture to 90°C. The hydrogen peroxide in the mixture was monitored to determine the decomposition reaction rate (0.0026 min -1 ), and the decomposition efficiency of hydrogen peroxide after 1 h of treatment (18%) were calculated.

[0053] Comparative Example 4 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 50,000 mg / L hydrogen peroxide was prepared. The mixture was irradiated with infrared light (1500 nm to 6500 nm / 4.21 W / cm 2 ), which heated the mixture to 105°C. The hydrogen peroxide in the mixture was monitored to determine the decomposition rate (0.0039 min -1 ), and the decomposition efficiency of hydrogen peroxide after 1 h of treatment (28%) were calculated.

[0054] Comparative Example 5 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 50,000 mg / L hydrogen peroxide was prepared. The mixture was irradiated with infrared light (1500 nm to 6500 nm / 4.21 W / cm 2 ), which heated the mixture to 120°C. The hydrogen peroxide in the mixture was monitored to determine the decomposition reaction rate (0.0073 min -1 ), and the decomposition efficiency of hydrogen peroxide after 1 h of treatment (46%) were calculated.

[0055] Comparative Example 6 A 200 mL mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 55,000 mg / L hydrogen peroxide was prepared. The mixture was irradiated with infrared light (1500 nm to 6500 nm / 4.21 W / cm 2 ), which heated the mixture to 130°C. The hydrogen peroxide in the mixture was tracked and the decomposition reaction rate (0.0173 min -1 ), and the decomposition efficiency of hydrogen peroxide after 1 h of treatment (68%) were calculated.

[0056] Example 1 A mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 47,500 mg / L of hydrogen peroxide was prepared. The mixture was irradiated with infrared rays (1,500 nm to 6,500 nm / 4.21 W / cm 2 ) and ultraviolet light (254 nm / 0.22 W / cm 2 ), which heated the mixture to 130°C. The hydrogen peroxide in the mixture was monitored to determine the decomposition reaction rate (0.0239 min -1 The decomposition efficiency of hydrogen peroxide after 1 hour of treatment (about 84%) was calculated. The sulfuric acid concentration of the treated mixture was 60 wt%, and the hydrogen peroxide concentration was 50 mg / L.

[0057] Example 2 A waste solution of sulfuric acid and hydrogen peroxide containing 76 wt% sulfuric acid and 6250 mg / L of hydrogen peroxide was generated at the factory. The mixture was subjected to infrared irradiation (1500 nm to 6500 nm / 4.21 W / cm 2 ) and ultraviolet light (254 nm / 0.22 W / cm 2 ), which heated the mixture to 130°C. The hydrogen peroxide in the mixture was monitored to determine its decomposition rate (0.0228 min -1 The decomposition efficiency of hydrogen peroxide after 1 hour of treatment (about 82%) was calculated. The sulfuric acid concentration of the treated mixture was 76 wt%, and the hydrogen peroxide concentration was 50 mg / L.

[0058] Example 3 See Figure 1. A cylindrical container with a diameter of 40 cm and a length of 180 cm was selected for use. Four infrared lamps (diameter 3 cm, length 180 cm, emission wavelength 1500 nm to 6500 nm, energy density 9.27 W / cm) were used. 2 ) and three ultraviolet lamps (diameter 3 cm, length 180 cm, emission wavelength 253.7 nm, energy density 1.02 W / cm 2 ) was placed in the container. The arrangement of the infrared lamp and the ultraviolet lamp can be seen in FIG.

[0059] A mixture of sulfuric acid and hydrogen peroxide containing 60 wt% sulfuric acid and 47,500 mg / L hydrogen peroxide was prepared. The mixture was introduced into the vessel through an inlet at the bottom. The flow rate of the mixture was 2.59 m / h. The mixture was irradiated with infrared and ultraviolet light and heated to 130°C. The air hole in the lid was connected to an exhaust system to exhaust the oxygen produced. The treated mixture, which had passed through a three-way valve (used to exhaust the oxygen in the mixture), was introduced into the inlet at the bottom of the vessel. The treated mixture was circulated back into the vessel. The hydrogen peroxide in the mixture was tracked to determine the decomposition reaction rate (0.024 min -1 The decomposition efficiency of hydrogen peroxide after 1 hour of treatment (about 85%) was calculated. The sulfuric acid concentration of the treated mixture was 60 wt%, and the hydrogen peroxide concentration was 50 mg / L.

[0060] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed methods and materials. It is intended that the specification and various embodiments be considered as exemplary only, with the true scope of the present disclosure being indicated by the following claims and their equivalents. [Explanation of symbols]

[0061] a-a' cross section 100...device 101...container 103...Entrance 105...Exit 107 Infrared lamp 109...Ultraviolet lamp 111,119...Bracket 113...Three-way valve 115...lid 117 Air vent

Claims

1. 1. An apparatus for recycling sulfuric acid, comprising: A container having an interior space; an inlet located on a first side of the vessel for introducing a liquid containing sulfuric acid and hydrogen peroxide; an outlet located on a second side of the vessel for discharging treated liquid from the vessel, the outlet being opposed to the first side and the second side; an infrared lamp located within the interior space of the vessel and in contact with the liquid; an ultraviolet lamp located within the interior space of the vessel and in contact with the liquid; a bracket located in the internal space of the container and connecting the infrared lamp and the ultraviolet lamp; A lid covering the upper side of the container and having an air hole; Including, An apparatus in which the infrared rays emitted from the infrared lamp and the ultraviolet rays emitted from the ultraviolet lamp decompose the hydrogen peroxide in the liquid into water and oxygen, the infrared rays heat the liquid, and the oxygen is discharged from the air hole.

2. 10. The apparatus of claim 1 further comprising a three-way valve connected to said outlet for exhausting said oxygen.

3. 2. The apparatus of claim 1, wherein the infrared radiation has a wavelength of 1500 nm to 6500 nm.

4. 2. The apparatus of claim 1, wherein the ultraviolet light has a wavelength of 230 nm to 275 nm.

5. The energy density of each of the infrared rays and the ultraviolet rays is 0.1 W / cm ２ to 16 W / cm ２ 2. The apparatus of claim 1 ,

6. 2. The apparatus of claim 1, wherein the ratio of energy densities of the infrared radiation to the ultraviolet radiation is from 4:1 to 20:

1.

7. 2. The apparatus of claim 1, further comprising other infrared lamps and other ultraviolet lamps, wherein a ratio of a total cross-sectional area of ​​the infrared lamps to a cross-sectional area of ​​the vessel is from 1:100 to 5:100, and a ratio of a total cross-sectional area of ​​the ultraviolet lamps to a cross-sectional area of ​​the vessel is from 1:100 to 5:

100.

8. 8. The apparatus of claim 7, wherein the infrared lamps are arranged in a cross-section of the container to define a first circle and the ultraviolet lamps are arranged in a cross-section of the container to define a second circle, the first and second circles being concentric, and the diameter of the first circle being greater than the diameter of the second circle.

9. 2. The apparatus of claim 1, wherein the flow rate of the liquid introduced through the inlet is from 0.5 m / hr to 3 m / hr.

10. 2. The apparatus of claim 1, wherein the liquid has a sulfuric acid concentration of 50 wt% to 70 wt%.

11. 2. The apparatus of claim 1, wherein the liquid has a hydrogen peroxide concentration of 10,000 mg / L to 60,000 mg / L and the treated liquid has a hydrogen peroxide concentration of 50 mg / L or less.

12. The device of claim 1 , wherein the sidewall of the container has a textured structure.

13. 1. A method for recycling sulfuric acid, comprising the steps of: Providing a liquid in a container containing sulfuric acid and hydrogen peroxide; decomposing the hydrogen peroxide in the liquid into water and oxygen using infrared and ultraviolet light, and heating the liquid to 90°C to 130°C by the infrared light; collecting the treated liquid; The method includes:

14. 14. The method of claim 13, implemented using the device of claim 1.

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