A catalyst for modified gallium arsenide wafer cutting and grinding waste and a preparation method and application thereof

Abstract

This invention relates to the field of photocatalysis technology, specifically to a modified gallium arsenide wafer grinding waste catalyst, its preparation method, and its application. The preparation method includes the following steps: Step 1: Grinding the gallium arsenide grinding waste, washing it with solvent, and drying it to obtain powder; Step 2: Placing the powder obtained in Step 1 into a covered crucible and placing it in a muffle furnace for heat treatment. After maintaining the heat treatment for a period of time, the mixture is naturally cooled to room temperature to obtain a solid material that has undergone thermal polymerization treatment; Step 3: Grinding the thermally polymerized solid material into powder, washing it several times with solvent in a centrifuge, and finally filtering and drying it to obtain the modified gallium arsenide wafer grinding waste catalyst. This technical solution achieves efficient resource utilization through "waste treatment," directly converting hazardous solid waste into a high-value-added catalyst, and simultaneously solving the problems of waste disposal costs and environmental risks.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a modified gallium arsenide wafer cutting and grinding waste catalyst, its preparation method, and its application. Background Technology

[0002] Gallium arsenide (GaAs), a core material for second-generation compound semiconductors, is widely used in high-speed electronic devices, photovoltaic cells, and light-emitting diodes. Its wafer manufacturing process generates a large amount of cutting and grinding waste, commonly known as "ash." This waste, containing toxic arsenic, is explicitly classified as hazardous solid waste, and its safe disposal has long been an environmental challenge for the semiconductor industry. Traditional treatment approaches primarily focus on "harmlessness" and "low-value utilization," failing to fully explore its intrinsic value as a high-purity semiconductor material.

[0003] Meanwhile, photocatalytic degradation in advanced oxidation technologies is an effective method for treating recalcitrant organic wastewater (such as dye wastewater containing methylene blue). The core of this approach lies in developing efficient, stable, and low-cost photocatalysts. Current mainstream research focuses on complex modifications to traditional photocatalysts to enhance their visible light activity or on exploring novel catalytic materials. However, these strategies often rely on high-purity commercial chemical raw materials and sophisticated synthesis processes, resulting in high catalyst costs and hindering their large-scale engineering applications.

[0004] In summary, the current technological landscape presents two independent dilemmas: on the one hand, GaAs waste, with its intrinsic semiconductor properties, is treated as an environmental burden, resulting in resource waste; on the other hand, the preparation of high-performance photocatalysts urgently requires more economical raw material sources. Combining these two needs—that is, transforming hazardous GaAs waste into high-value-added photocatalytic materials—has become a highly promising research direction for realizing the concept of "treating waste with waste and turning waste into treasure."

[0005] In view of this, we propose a modified gallium arsenide wafer cutting and grinding waste catalyst, its preparation method and application. Summary of the Invention

[0006] The purpose of this invention is to provide a modified gallium arsenide wafer cutting and grinding waste catalyst, its preparation method, and its application, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A modified gallium arsenide wafer cutting and grinding waste catalyst, its preparation method, and its application, comprising the following steps: Step 1: Grind the gallium arsenide cutting and grinding waste, clean it with solvent and dry it to obtain powder; Step 2: Place the powder obtained in Step 1 into a covered crucible and place it in a muffle furnace for heat treatment. After maintaining the heat treatment for a period of time, allow it to cool naturally to room temperature to obtain a solid material that has undergone thermal polymerization treatment. Step 3: Grind the solid material after thermal polymerization into powder, wash it several times with solvent in a centrifuge, and finally filter and dry it to obtain the modified gallium arsenide wafer cutting and grinding waste catalyst.

[0009] Preferably, the solvents used in step one are deionized water and anhydrous ethanol, the cleaning method is to first clean with deionized water 3-5 times, and then clean with anhydrous ethanol 1-3 times, and the drying is carried out in a constant temperature oven at 60°C for 8-12 hours.

[0010] Preferably, the heat treatment in step two involves heating to 800°C at a rate of 2°C / min and maintaining the temperature for 1-5 hours.

[0011] Preferably, the solvents used in step three are deionized water and anhydrous ethanol. The cleaning method involves first washing with deionized water 3-5 times, and then washing with anhydrous ethanol 1-3 times. The drying method involves placing the powder in an oven and drying it at 60°C.

[0012] A modified gallium arsenide wafer cutting and grinding waste catalyst is prepared by the above-described preparation method.

[0013] The above-mentioned modified gallium arsenide wafer cutting waste catalyst is used in the photocatalytic degradation of methylene blue.

[0014] Preferably, it is used as a photocatalyst for the photocatalytic degradation of methylene blue, specifically in the following steps: The modified gallium arsenide wafer cutting waste catalyst was mixed with the methylene blue solution to be treated and stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium. Then, it was irradiated with a 500W xenon lamp for 180 minutes. Samples were taken at intervals, and the concentration of methylene blue in the reaction solution was detected by spectrophotometry.

[0015] Preferably, the concentration of methylene blue in the methylene blue solution to be treated is 10 mg·L⁻¹. -1 The volume of the methylene blue solution was 45 mL, and the amount of modified gallium arsenide wafer cutting and grinding waste catalyst added was 30 mg.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention transforms gallium arsenide (GaAs) wafer cutting and grinding waste into a high-efficiency photocatalytic material through a one-step thermal polymerization method. Its beneficial effects are mainly reflected in three aspects: First, it achieves efficient resource utilization through "waste-to-waste" conversion, directly transforming hazardous solid waste into a high-value-added catalyst, simultaneously solving the problems of waste disposal costs and environmental risks; second, it obtains a practical material with superior performance and stability. The modified gallium arsenide wafer cutting and grinding waste catalyst has high crystallinity and a dense structure, and can completely degrade 10 mg / L methylene blue within 180 minutes under simulated sunlight. Furthermore, its excellent pressure resistance and corrosion resistance ensure long-term stable catalytic performance; third, it provides an economical and feasible new approach to pollution control. This process is simple and efficient, with near-zero raw material costs, providing an innovative solution for organic wastewater treatment that combines high catalytic activity, high stability, and low environmental impact. Attached Figure Description

[0017] Figure 1 The XRD patterns of Comparative Example 1 and Examples 1-5 of the present invention are shown below. Figure 2 The FTIR spectra of Comparative Example 1 and Examples 1-5 of the present invention are shown below; Figure 3 XPS spectra of the full spectrum (a), C 1s (b), Zr 3d (c), Si 2p (d), Al 2p (e), O 1s (f), Ga 2p (g), and As 3d (h) of Comparative Example 1 and Example 4 of the present invention; Figure 4 SEM images of Comparative Example 1(a) and Example 4(b); Figure 5 These are UV-vis images of Comparative Example 1 and Examples 1-5 of the present invention; Figure 6 The images show the photocatalytic degradation effect of methylene blue in Comparative Example 1 and Examples 1-5 of this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the gallium arsenide wafer cutting and grinding waste used in this invention comes from the actual production process of Jiangsu Ningda Environmental Protection Co., Ltd.; unless otherwise specified, all chemical reagents involved in this invention are purchased through commercial channels.

[0020] Comparative Example 1: The collected gallium arsenide cutting and grinding waste was ground and sieved, washed 4 times with deionized water, washed once with anhydrous ethanol, and finally dried in a constant temperature oven at 60℃ for 10 hours to obtain powder, which was named GaAs Cutting Slag.

[0021] Example 1: A method for preparing GaAs-CS-800-1 nanocatalyst using gallium arsenide wafer cutting and grinding waste as a precursor, comprising the following steps: (1) Weigh 10g of GaAs Cutting Slag and put it into a covered crucible. Place it in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min. Then calcine it for 1h.

[0022] (2) After naturally cooling to room temperature, wash with deionized water, centrifuge at 6000 rpm for 10 min, wash repeatedly 4 times, and then wash once with anhydrous ethanol; finally dry in a constant temperature oven at 60℃ for 10 h to obtain modified gallium arsenide wafer cutting and grinding waste catalyst, named GaAs-CS-800-1.

[0023] Example 2: A method for preparing a modified gallium arsenide wafer cutting and grinding waste catalyst, comprising the following steps: (1) Weigh 10g of GaAs Cutting Slag and put it into a covered crucible. Place it in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min. Then calcine it for 2h.

[0024] (2) After naturally cooling to room temperature, wash with deionized water, centrifuge at 6000 rpm for 10 min, wash repeatedly 4 times, and then wash once with anhydrous ethanol; finally dry in a constant temperature oven at 60℃ for 10 h to obtain modified gallium arsenide wafer cutting and grinding waste catalyst, named GaAs-CS-800-2.

[0025] Example 3: A method for preparing a modified gallium arsenide wafer cutting and grinding waste catalyst, comprising the following steps: (1) Weigh 10g of GaAs Cutting Slag and put it into a covered crucible. Place it in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min. Then calcine it for 3h.

[0026] (2) After naturally cooling to room temperature, wash with deionized water, centrifuge at 6000 rpm for 10 min, wash repeatedly 4 times, and then wash once with anhydrous ethanol; finally dry in a constant temperature oven at 60℃ for 10 h to obtain modified gallium arsenide wafer cutting and grinding waste catalyst, named GaAs-CS-800-3.

[0027] Example 4: A method for preparing a modified gallium arsenide wafer cutting and grinding waste catalyst, comprising the following steps: (1) Weigh 10g of GaAs Cutting Slag and put it into a covered crucible. Place it in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min. Then calcine it for 4h.

[0028] (2) After naturally cooling to room temperature, wash with deionized water, centrifuge at 6000 rpm for 10 min, wash repeatedly 4 times, and then wash once with anhydrous ethanol; finally dry in a constant temperature oven at 60℃ for 10 h to obtain modified gallium arsenide wafer cutting and grinding waste catalyst, named GaAs-CS-800-4.

[0029] Example 5: A method for preparing a modified gallium arsenide wafer cutting and grinding waste catalyst, comprising the following steps: (1) Weigh 10g of GaAs Cutting Slag and put it into a covered crucible. Place it in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min. Then calcine it for 5h.

[0030] (2) After naturally cooling to room temperature, wash with deionized water, centrifuge at 6000 rpm for 10 min, wash repeatedly 4 times, and then wash once with anhydrous ethanol; finally dry in a constant temperature oven at 60℃ for 10 h to obtain modified gallium arsenide wafer cutting and grinding waste catalyst, named GaAs-CS-800-5.

[0031] Example 6: The modified gallium arsenide wafer cutting waste catalyst obtained in Examples 1-5 was used for photocatalytic degradation of methylene blue, specifically according to the following steps: 30 mg of modified gallium arsenide wafer grinding waste catalyst was mixed with 45 mL of a 10 mg·L⁻¹ solution. -1 The mixture was stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium, and then irradiated with a 500W xenon lamp for 180 minutes. Samples were taken at intervals, and the concentration of methylene blue in the reaction solution was detected by spectrophotometry.

[0032] The XRD patterns of the photocatalytic materials prepared in Comparative Example 1 and Examples 1-5 of this invention are as follows: Figure 1 As shown. Comparative Example 1 and Examples 1-5 all exhibit significant phase structures of ZrSiO4, Al2O3, and GaAs. The value corresponding to ZrSiO4 is 20.15. o (101), 27.05 o (200), 33.89 o (211), 35.71 o (112), 38.54 o (220), 40.74 o (202), 43.93 o (301), 47.55o (103), 52.22 o (321), 53.54 o (312), 55.72 o (400), 62.94 o (420), 67.80 o (332), 73.48 o (431), 75.41 o (224) (PDF#06-0266). Corresponding to 25.56 for Al2O3. o (012), 35.20 o (104), 37.81 o (110), 43.36 o (113), 52.55 o (024), 57.51 o (116), 66.50 o (214), 68.91 o (300), 77.08 o (119) (PDF#46-1212). Corresponding to 26.98 GaAs. o (111), 45.30 o (220), 53.61 o (311) (PDF#65-0234). With the increase of heat treatment time, the overall characteristic peaks showed a trend of increasing peak value, indicating that the crystallinity of each substance increased.

[0033] The infrared spectra of the photocatalytic materials prepared in Comparative Example 1 and Examples 1-5 of this invention are as follows: Figure 2 As shown in the figure, this diagram clearly illustrates the significant evolution of the surface chemical structure of GaAs grinding waste (mainly containing ZrSiO4, Al2O3, and GaAs) after heat treatment at 800℃ for different times (1-5 hours). The original waste has a thickness of 400-1000 cm³. -1 Multiple characteristic peaks within the range correspond to vibrations of the original crystal phase (such as Si-O and Al-O bonds). After heat treatment, these characteristic peaks were significantly weakened, indicating that the high-temperature treatment destroyed the original ordered structure; at the same time, all heat-treated samples showed a decrease in the vibration frequency of the crystal phase within the range of 1000-1200 cm⁻¹. -1 A significantly enhanced broad absorption band appears, mainly due to the heat treatment-induced formation of the amorphous aluminosilicate network and the vibrations of the Ga / Al oxide, while at ~1600 cm⁻¹... -1The new peaks indicate that residual organic pollutants in the waste underwent in-situ carbonization, forming amorphous carbon or graphitized carbon. As the calcination time increased from 1 hour to 5 hours, the intensity of these newly formed peaks generally increased (most significantly in the 5-hour sample), indicating that the longer heat treatment time promoted the structural reconstruction, surface amorphization, and carbonization processes of the solid waste components. This in-situ generation of surface amorphization and carbonaceous matter induced by simple heat treatment is expected to synergistically enhance the material's adsorption capacity for reactants and the separation efficiency of photogenerated charges, thus providing crucial structural evidence for the direct conversion of hazardous solid waste into functional materials with potential photocatalytic activity.

[0034] The elemental XPS spectra of the photocatalytic materials prepared in Comparative Example 1 and Example 4 of this invention are as follows: Figure 3 As shown in the figure, the XPS spectra comprehensively reveal the mechanism by which heat treatment reconstructs the chemical composition and valence state of the GaAs cutting and grinding waste surface. After treatment at 800℃ for 4 hours, a fundamental transformation occurred on the sample surface: the C1s spectrum showed carbonization of organic pollutants, forming sp... 2 A carbon-dominated conductive carbon layer (~284.8 eV) was observed. The O 1s spectrum showed no significant change in the lattice oxygen ratio, indicating that the heat treatment process did not introduce external oxygen but instead drove the redistribution and chemical state transformation of surface oxygen species. Peak shifts and intensity changes in the Zr 3d, Si 2p, and Al 2p spectra confirmed the high-temperature reconstruction of ZrSiO4 and Al2O3 components. Chemical shifts in the Ga 2p and As 3d spectra clearly pointed to the oxidation of GaAs to form Ga2O3 and As2O3 on the GaAs surface. These changes synergistically constructed a composite surface structure characterized by a "conductive carbon layer encapsulating multi-component oxides." This structure not only enhances light absorption and charge separation efficiency but also provides abundant active sites for reactant adsorption and surface catalysis, thus providing a crucial surface chemical basis for the photocatalytic resource recovery of inert solid waste.

[0035] SEM images of the photocatalytic materials prepared in Comparative Example 1 and Example 4 of this invention are as follows: Figure 4 As shown in the figure. This figure visually reveals the significant surface morphology reconstruction that occurs after the material is heat-treated at 800°C for 4 hours. Original waste ( Figure 4 a) The surface is relatively smooth and dense, but a small number of particles are still attached, which is consistent with the characteristics of industrial cutting waste. After heat treatment ( Figure 4(b) The surface becomes extremely rough and exhibits a distinct three-dimensional porous and aggregated structure, with increased particle size and mutual adhesion, forming abundant pores and gaps. This evolution from "smooth" to "rough and porous" is corroborated by the formation of new functional groups observed in infrared spectroscopy and the strong enhancement of carbon / oxygen signals in XPS: high-temperature treatment not only removes the original surface contaminants but also promotes vigorous reactions among the various components inside the waste (such as organic carbonization, oxide generation, and sintering), ultimately constructing a composite surface with high specific surface area and complex roughness. This morphology is extremely beneficial for photocatalysis: the rough and porous surface greatly increases the light-harvesting efficiency and the number of active sites, and provides channels for reactant adsorption and mass transfer, thus synergizing with the carbon / oxide heterostructure induced by heat treatment inside the material to jointly optimize the separation of photogenerated charges and surface reaction kinetics.

[0036] The ultraviolet-visible absorption spectra of the photocatalytic materials prepared in Comparative Example 1 and Examples 1-5 of this invention are as follows: Figure 5 As shown, the intrinsic light absorption properties of the catalyst changed significantly after heat treatment. The absorption edge of the bulk GaAs cutting waste was located at approximately 708 nm, while the absorption edge of the modified sample red-shifted to approximately 745 nm, moving about 37 nm towards longer wavelengths. This red-shift phenomenon directly corresponds to a reduction in the optical band gap of the material, meaning that the modified material can absorb and utilize visible light and even near-infrared light with longer wavelengths and lower energy, greatly broadening its photoresponse range, which is crucial for improving the utilization rate of sunlight.

[0037] The photocatalytic degradation performance of the materials prepared in Comparative Example 1 and Examples 1-5 of this invention is compared to that of methylene blue. Figure 6As shown, during the dark adsorption stage (-30 to 0 minutes), the modified samples showed a slight enhancement in their adsorption capacity for methylene blue, especially those treated for 4 and 5 hours. This directly confirms the previous characterization results showing a rougher, more porous surface and an increase in functional groups, which is beneficial for the enrichment of reactants. After entering the light irradiation stage, the performance of all modified samples in degrading methylene blue significantly improved, with GaAs-CS-800-4 exhibiting the best performance, almost completely degrading methylene blue after 180 minutes of irradiation. This trend is highly consistent with the structural evolution of the material: longer heat treatment time promotes more complete surface carbonization, the formation of amorphous oxide layers, and a more optimized heterojunction structure (as shown by FT-IR, XPS, and SEM), thereby synergistically improving the material's light absorption (UV-Vis spectrum redshift and enhancement), charge separation and transport efficiency, ultimately manifesting as superior photocatalytic degradation kinetics. However, excessive heat treatment time leads to a reduction in active sites, limited mass transfer, and increased charge recombination, resulting in performance degradation. This provides a key basis for precisely controlling the structure and performance of solid waste-derived catalysts by controlling the heat treatment time. This figure strongly demonstrates that industrial solid waste can be effectively converted into high-value-added photocatalytic materials through one-step thermal treatment.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a catalyst from modified gallium arsenide wafer cutting and grinding waste, characterized in that, Includes the following steps: Step 1: Grind the gallium arsenide cutting and grinding waste, clean it with solvent and dry it to obtain powder; Step 2: Place the powder obtained in Step 1 into a covered crucible and place it in a muffle furnace for heat treatment. After maintaining the heat treatment for a period of time, allow it to cool naturally to room temperature to obtain a solid material that has undergone thermal polymerization treatment. Step 3: Grind the solid material after thermal polymerization into powder, wash it several times with solvent in a centrifuge, and finally filter and dry it to obtain the modified gallium arsenide wafer cutting and grinding waste catalyst.

2. The method for preparing the modified gallium arsenide wafer cutting and grinding waste catalyst according to claim 1, characterized in that, The solvents mentioned in step one are deionized water and anhydrous ethanol. The cleaning method is to first clean with deionized water 3-5 times, and then clean with anhydrous ethanol 1-3 times. The drying is carried out in a constant temperature oven at 60°C for 8-12 hours.

3. The method for preparing the modified gallium arsenide wafer cutting and grinding waste catalyst according to claim 1, characterized in that, The heat treatment in step two involves heating to 800°C at a rate of 2°C / min and maintaining the temperature for 1-5 hours.

4. The method for preparing the modified gallium arsenide wafer cutting and grinding waste catalyst according to claim 1, characterized in that, The solvents used in step three are deionized water and anhydrous ethanol. The cleaning method is to first clean with deionized water 3-5 times, and then clean with anhydrous ethanol 1-3 times. The drying method is to place the powder in an oven and dry it at 60°C.

5. A modified gallium arsenide wafer cutting and grinding waste catalyst, characterized in that, It is prepared by the method of any one of claims 1-4.

6. The application of the modified gallium arsenide wafer cutting waste catalyst according to claim 5 in the photocatalytic degradation of methylene blue.

7. The application of the modified gallium arsenide wafer grinding waste catalyst according to claim 6 in the photocatalytic degradation of methylene blue, characterized in that, It is used as a photocatalyst for the photocatalytic degradation of methylene blue, specifically in the following steps: The modified gallium arsenide wafer cutting waste catalyst was mixed with the methylene blue solution to be treated and stirred in the dark for 30 minutes to reach adsorption-desorption equilibrium. Then, it was irradiated with a 500W xenon lamp for 180 minutes. Samples were taken at intervals, and the concentration of methylene blue in the reaction solution was detected by spectrophotometry.

8. The application of the modified gallium arsenide wafer grinding waste catalyst according to claim 7 in the photocatalytic degradation of methylene blue, characterized in that, The concentration of methylene blue in the methylene blue solution to be treated is 10 mg·L -1 The volume of the methylene blue solution is 45 mL, and the addition amount of the modified gallium arsenide wafer cutting and grinding waste material catalyst is 30 mg.

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