Fenton-coagulation composite medicament for deep copper removal of semiconductor wastewater as well as preparation method and application of Fenton-coagulation composite medicament

Abstract

The invention relates to the technical field of copper-containing wastewater treatment, in particular to a Fenton-coagulation composite reagent for deep copper removal of semiconductor wastewater as well as a preparation method and application thereof. Composite microcrystals are prepared from ferrous ions, hydrogen peroxide and polyacrylamide, and the composite microcrystals are embedded into pores of the porous activated carbon to obtain the composite agent. The preparation method comprises the following steps: (1) adding a hydrogen peroxide solution into a ferrous salt solution under a stirring condition, slowly adding a polyacrylamide solution under a low-temperature condition, and continuing aging or standing after the polyacrylamide solution is added, so as to promote the formation of a composite microcrystal precursor; and (2) contacting the composite microcrystal precursor prepared in the step (1) with porous activated carbon, so that the composite microcrystals are embedded into pores of the activated carbon and are attached to the surface and pores of the activated carbon, thereby obtaining the composite medicament. The method is superior to treatment modes such as traditional Fenton, simple blending and conventional alkali precipitation in the aspects of effluent copper concentration, removal rate and operation stability, and has a good engineering application prospect.

Description

Technical Field

[0001] This invention relates to the field of copper-containing wastewater treatment technology, specifically to a Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater, its preparation method, and its application. Background Technology

[0002] Semiconductor manufacturing processes often generate copper-containing wastewater. Copper ions often form stable complexes with organic ligands such as EDTA and citric acid, giving them extremely high chemical stability in water. This makes it difficult to achieve efficient and stable removal using traditional alkaline neutralization and precipitation methods.

[0003] Currently, common engineering treatment technologies for copper-containing wastewater from semiconductors, especially complexed copper wastewater, mainly include chemical precipitation, Fenton oxidation, micro-electrolysis, electrochemical methods, coagulation sedimentation, and adsorption. While single-alkali precipitation processes can effectively remove free copper ions, they are extremely ineffective at removing stable complexed copper bound to organic ligands. Fenton oxidation, by using hydroxyl radicals to disrupt the coordination structure between copper and organic complexing agents, dissociates the complexed copper into free copper ions, demonstrating significant application potential in the treatment of complex copper-containing wastewater. Industrially, the common approach for treating complexed copper is "first break the complex, then coagulate, then separate," meaning that the complex is first broken down through oxidation or micro-electrolysis, followed by coagulation sedimentation and filtration to separate and remove copper ions.

[0004] However, current technologies primarily rely on multi-unit series processing, requiring separate oxidation and complex-breaking, coagulation and sedimentation, and associated adsorption or filtration units. While this process can improve copper removal efficiency to some extent, it generally suffers from problems such as long process flow, numerous equipment units, large footprint, complex step-by-step reagent dosing control, and insufficient synergy among multiple action mechanisms. These issues make it difficult to adapt to the compact transformation and long-term stable operation of end-of-pipe wastewater treatment systems in semiconductor enterprises. For low-concentration, complex-complexed copper wastewater, achieving efficient coupling of complex-breaking oxidation, adsorption enrichment, and flocculation sedimentation, and developing integrated composite reagents that combine reaction and separation functions, has become an urgent problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the existing defects and provide a Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater, its preparation method and application. Iron / hydrogen peroxide / PAM composite microcrystals are prepared and loaded into the pores of unmodified porous activated carbon to obtain an integrated composite agent with three functions: complex breaking oxidation, adsorption enrichment and flocculation bridging. The "complex breaking-oxidation-adsorption-coagulation" synergistic treatment is achieved through a single agent, which significantly improves the deep treatment efficiency and applicability of semiconductor complexed copper wastewater.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater, which is prepared by using ferrous ions, hydrogen peroxide and polyacrylamide to obtain composite microcrystals, and then embedding the composite microcrystals into the pores of porous activated carbon to obtain the composite agent.

[0007] Preparation method of Fenton-coagulant composite agent for advanced copper removal from semiconductor wastewater

[0008] (1) Preparation of composite microcrystalline precursor

[0009] Hydrogen peroxide solution was added to the ferrous salt solution under stirring conditions, and polyacrylamide solution was slowly added under low temperature conditions. After the polyacrylamide solution was added, aging or standing was continued to promote the formation of composite microcrystal precursors.

[0010] (2) Loading and embedding of composite microcrystals in porous activated carbon

[0011] The composite microcrystalline precursor obtained in step (1) is brought into contact with porous activated carbon, so that the composite microcrystalline is embedded in the pores of the activated carbon and attached to its surface and channels, thereby obtaining a composite agent.

[0012] Furthermore, the ferrous salt is a soluble ferrous salt, selected from one or both of ferrous sulfate or ferrous chloride, preferably ferrous sulfate;

[0013] Fe in the divalent iron salt solution 2+ The concentration is 0.02–0.10 mol / L, preferably 0.03–0.08 mol / L, and more preferably 0.05 mol / L.

[0014] Furthermore, the mass fraction of the hydrogen peroxide is 20% to 35%, preferably 30%;

[0015] The hydrogen peroxide and Fe 2+ The molar ratio is 1:1 to 4:1, preferably 1.5:1 to 3:1, and more preferably 2:1 to 3:1.

[0016] Furthermore, the polyacrylamide is anionic, nonionic, or weakly cationic polyacrylamide, preferably anionic polyacrylamide, and the mass fraction of the polyacrylamide solution is 0.05% to 0.30%, preferably 0.1% to 0.2%.

[0017] The amount of polyacrylamide added is 1% to 10% of the mass of the divalent iron salt, preferably 3% to 8%, and more preferably 3% to 5%.

[0018] Furthermore, in step (1), the low temperature is 0-10℃, preferably 3-8℃, more preferably 5℃; the stirring speed is 200-600 rpm, preferably 300-500 rpm; and the stirring time is 20-60 min, preferably 25-40 min, more preferably 30 min.

[0019] The aging or settling time is 0.5 to 2 hours, preferably 0.5 to 1.5 hours.

[0020] Furthermore, the activated carbon is unmodified activated carbon, preferably one of wood-based activated carbon, coal-based activated carbon, or fruit shell activated carbon, with a particle size of 80-300 mesh, preferably 100-200 mesh.

[0021] Furthermore, the mass ratio of the composite microcrystalline precursor to activated carbon is 1:1 to 1:4, preferably 1:1.5 to 1:3, and more preferably 1:2 to 1:3.

[0022] Furthermore, the embedding in step (2) can be carried out by one or more of spray drying, impregnation drying or physical grinding embedding methods, preferably by a combination of impregnation drying and physical grinding embedding.

[0023] The embedding conditions are 4–12 h, 50–70 °C, and drying for 8–10 h; preferably 6–10 h, 55–65 °C, and drying for 8–12 h; more preferably 8 h, 60 °C, and drying for 10 h.

[0024] Application of Fenton-coagulant composite agents for advanced copper removal from semiconductor wastewater

[0025] Adjust the initial pH of the copper-containing semiconductor wastewater to be treated, add Fenton-coagulation composite agent to the wastewater at a dosage of 0.2–2.0 g / L, and react by coagulation and stirring after the agent is added. First, stir rapidly for 5–15 min at a speed of 150–300 rpm; then stir slowly for 10–20 min at a speed of 40–80 rpm.

[0026] After the stirring reaction is completed, the wastewater is allowed to settle for 20-40 minutes. After settling, solid-liquid separation is carried out by gravity sedimentation, inclined plate sedimentation, filtration or centrifugation to remove the formed flocs and load carrier particles, and obtain low copper water.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This application achieves the breaking down, oxidation, adsorption, and coagulation sedimentation of complexed copper using a single composite agent, simplifying the traditional multi-unit treatment process. It exhibits good adaptability to complexed copper wastewater containing EDTA, citric acid, etc., and can stably control the effluent copper concentration below 0.5 mg / L. Activated carbon in the system not only adsorbs organic matter and oxidizes intermediate products but also serves as a loading framework for Fenton components and PAM, improving system synergy. PAM simultaneously participates in the construction of composite microcrystals and subsequent flocculation bridging, enhancing solid-liquid separation. This invention outperforms traditional Fenton, simple blending, and conventional alkaline precipitation methods in terms of effluent copper concentration, removal rate, and operational stability, demonstrating promising engineering application prospects. Attached Figure Description

[0029] Figure 1 This is a physical image of the Fenton-coagulant composite agent prepared according to the present invention. Detailed Implementation

[0030] 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.

[0031] Example 1:

[0032] A Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater is prepared by using ferrous ions, hydrogen peroxide, and polyacrylamide to obtain composite microcrystals, which are then embedded in the pores of porous activated carbon to obtain the composite agent.

[0033] Preparation method of Fenton-coagulant composite agent for advanced copper removal from semiconductor wastewater

[0034] (1) Preparation of composite microcrystalline precursor

[0035] First, prepare a ferrous salt solution. The ferrous salt can be selected from one or two of ferrous sulfate, ferrous chloride, or other soluble ferrous salts, with ferrous sulfate being preferred. The ferrous salt solution contains Fe... 2+ The concentration can be controlled between 0.02 and 0.10 mol / L, preferably between 0.03 and 0.08 mol / L, and more preferably around 0.05 mol / L.

[0036] Hydrogen peroxide solution is added to the above-mentioned ferrous salt solution under stirring conditions. The hydrogen peroxide can be industrial hydrogen peroxide, preferably with a mass fraction of 20%–35%, more preferably around 30%. Hydrogen peroxide reacts with Fe... 2+ The molar ratio is controlled between 1:1 and 4:1, preferably between 1.5:1 and 3:1, and more preferably between 2:1 and 3:1, to control Fe. 2+ The ratio of hydrogen peroxide to H2O2 balances the system's oxidizing power and stability. Within this range, effective oxidation of the complexed copper ligands is ensured, while ineffective decomposition and increased reagent consumption due to excessive hydrogen peroxide are avoided.

[0037] Subsequently, a polyacrylamide (PAM) solution is slowly added under low-temperature conditions. The PAM can be anionic, nonionic, or weakly cationic, with anionic PAM being preferred. The mass fraction of the PAM solution can be 0.05%–0.30%, preferably 0.1%–0.2%. The amount of PAM added, based on the mass of divalent iron salt, can be controlled at 1%–10%, preferably 3%–8%, and more preferably 3%–5%. PAM, on the one hand, utilizes its long-chain structure to induce the formation of relatively stable composite microcrystals between iron salt and hydrogen peroxide; on the other hand, it provides a flocculation bridging function for subsequent wastewater treatment stages.

[0038] In this step, the system temperature is controlled at 0–10℃, preferably 3–8℃, and even more preferably around 5℃. Composite processing under low-temperature conditions helps slow down the rapid decomposition of hydrogen peroxide and promotes the formation of microcrystalline structures. The stirring speed can be controlled at 200–600 rpm, preferably 300–500 rpm; the stirring time is controlled at 20–60 min, preferably 25–40 min, and even more preferably around 30 min. After PAM is added, the system can be aged or allowed to stand for 0.5–2 h, preferably 0.5–1.5 h, to promote the formation of composite microcrystalline precursors. The rate and amount of PAM addition should be controlled to avoid excessively high local viscosity or uneven microcrystalline aggregation.

[0039] (2) Loading and embedding of composite microcrystals in porous activated carbon

[0040] The “iron-hydrogen peroxide-PAM” composite microcrystalline precursor obtained in step (1) is brought into contact with unmodified porous activated carbon, so that the composite microcrystalline enters the pores of the activated carbon and adheres to its surface and channels, thereby obtaining a composite loading system.

[0041] The activated carbon is preferably unmodified powdered activated carbon or fine-particle activated carbon, and can be one of wood-based activated carbon, coal-based activated carbon, or fruit shell activated carbon, with powdered activated carbon being preferred. Its particle size can be controlled between 80 and 300 mesh, preferably 100 to 200 mesh. Unmodified activated carbon retains its original specific surface area and hydrophobicity, and can be used to adsorb organic matter and oxidation intermediates in wastewater, while also serving as a carrier framework for composite microcrystals.

[0042] The mass ratio of composite microcrystals to activated carbon can be controlled between 1:1 and 1:4, preferably between 1:1.5 and 1:3, and more preferably between 1:2 and 1:3. When the proportion of activated carbon is too low, the adsorption and loading of the framework are insufficient; when the proportion is too high, the effective oxidizing component per unit mass of reagent is relatively low, which is not conducive to the complete breakdown of complexed copper.

[0043] The loading method in this step can be spray drying, impregnation drying, or physical grinding and embedding, with impregnation followed by drying and grinding being preferred. Specifically, the composite microcrystalline precursor can be mixed with activated carbon and impregnated for 4–12 h, preferably 6–10 h, and more preferably about 8 h; then dried at 50–70℃ for 8–12 h, preferably 55–65℃ for 8–10 h, and more preferably about 60℃ for 10 h; after drying, it can be lightly ground and sieved as needed to make the particle size distribution of the obtained composite agent more uniform.

[0044] If spray drying is used, the composite microcrystalline slurry can be mixed with activated carbon and then directly spray-dried, with process parameters adjustable according to equipment conditions. If physical grinding and embedding is used, the composite microcrystalline material can be more fully incorporated into the pores of the activated carbon through low-speed grinding after mixing. Regardless of the method used, the goal is to ensure that the activated carbon not only serves as a subsequent adsorption medium but also as a supporting framework for the Fenton and PAM components, forming a composite structure with sustained-release and synergistic effects.

[0045] Application of Fenton-coagulant composite agent for advanced copper removal from semiconductor wastewater

[0046] (1) Addition of compound agents to semiconductor wastewater

[0047] The obtained Fenton-coagulant composite agent is directly added to the copper-containing semiconductor wastewater to be treated, which is especially suitable for complexed copper wastewater containing organic complexing agents such as EDTA and citric acid. The initial concentration of copper ions in the wastewater to be treated can be 5-20 mg / L, preferably 8-15 mg / L, and more preferably around 10 mg / L, which is suitable for end-of-pipe deep treatment scenarios.

[0048] During treatment, the initial pH of the wastewater can be controlled between 3.0 and 7.0, preferably between 4.0 and 6.0, further preferably between 4.5 and 5.5, and optimally around 5.0. Within this pH range, on the one hand, it is beneficial for the gradual release of the Fenton component in the composite agent to exert its complex-breaking oxidation effect, and on the other hand, it also takes into account the subsequent flocculation and sedimentation effect.

[0049] The dosage of the compound reagent can be controlled between 0.2 and 2.0 g / L, preferably between 0.5 and 1.5 g / L, and more preferably between 1.0 and 1.5 g / L. When the dosage is too low, the complexed copper will not be sufficiently broken down, resulting in a low removal rate; when the dosage is too high, the reagent consumption will increase, and it may also lead to an increase in the turbidity of the system or an increase in fine flocs.

[0050] After the reagent is added, the reaction can be carried out by coagulation and stirring: first, stir rapidly for 5-15 minutes, preferably 8-12 minutes, and even more preferably 10 minutes, with a stirring speed of 150-300 rpm, preferably 180-250 rpm; then stir slowly for 10-20 minutes, preferably 12-18 minutes, and even more preferably 15 minutes, with a stirring speed of 40-80 rpm, preferably 50-70 rpm. The rapid stirring stage is conducive to the uniform dispersion of the reagent in the wastewater and the initiation of the complex-breaking oxidation reaction, while the slow stirring stage is conducive to the bridging and flocculation effect of PAM and promotes floc growth.

[0051] The Fenton component in the compound reagent can be released gradually, preferentially disrupting the complex structure between copper and organic ligands such as EDTA and citric acid, thus converting the complexed copper into a more easily removable form. At the same time, activated carbon adsorbs organic matter and oxidation intermediates in the wastewater, reducing their interference with copper removal. PAM promotes bridging and aggregation between microparticles, iron-based reaction products, and copper-related precipitates, forming larger flocs, thus achieving synergistic reaction and separation.

[0052] (2) Sedimentation separation and effluent acquisition

[0053] After the stirring reaction is complete, the wastewater is allowed to settle for 20–40 minutes, preferably 25–35 minutes, and more preferably around 30 minutes. After settling, solid-liquid separation can be performed by gravity sedimentation, inclined plate sedimentation, filtration, or centrifugation to remove the formed flocs and carrier particles, obtaining low-copper effluent. Under laboratory conditions, it is preferable to collect the supernatant after settling and filter it through a 0.45 μm filter membrane before measuring the copper ion concentration.

[0054] Example 2:

[0055] The preparation method of the Fenton-coagulant composite agent for advanced copper removal from semiconductor wastewater is as follows: The preparation method of Example 1 is followed by the specific preparation conditions:

[0056] Ferrous sulfate was selected as the source of divalent iron to control Fe. 2+ Concentration: 0.05 mol / L; H2O2 / Fe 2+ The molar ratio was controlled at 2:1; the amount of PAM added was 5% based on the mass of iron salt; the mixture was stirred at 5℃ for 30 min and aged for 1 h; then impregnated and loaded at a mass ratio of 1:2 between composite microcrystals and unmodified powdered activated carbon, and dried at 60℃ for 10 h to obtain the composite agent. Figure 1 This is a physical image of the Fenton-coagulant composite agent prepared in this application.

[0057] The prepared Fenton-coagulant composite agent was tested using simulated complexed copper wastewater.

[0058] Using the EDTA-Cu system as the test object, the initial copper ion concentration was controlled at 10 mg / L, the molar ratio of EDTA to Cu was 1.2:1, and the initial pH of the wastewater was 5.0. For each experiment, 250 mL of wastewater was collected and stirred in a beaker for the reaction.

[0059] During wastewater treatment, the dosage of the compound reagent was 1.0 g / L. After addition, the solution was first rapidly stirred for 10 min at 200 rpm, then slowly stirred for 15 min at 60 rpm. Following this, the solution was allowed to settle for 30 min, and the supernatant was filtered through a 0.45 μm filter membrane to determine the copper ion concentration. The copper concentration could be determined using atomic absorption spectrometry, ICP-MS, or spectrophotometry, and the copper removal rate was calculated.

[0060] The copper concentration after treatment was 0.36 mg / L, and the copper removal rate was 96.4%. The reaction process resulted in the formation of distinct flocs, good settling performance, and high clarity of the supernatant.

[0061] Example 3:

[0062] Based on Example 2, H2O2 / Fe 2+ The molar ratio was adjusted to 3:1, while other conditions remained unchanged. The copper concentration after treatment was 0.24 mg / L, and the copper removal rate was 97.6%. Under these conditions, the complexed copper was more thoroughly broken down, and the copper concentration in the effluent was further reduced.

[0063] Example 4:

[0064] Based on Example 2, the mass ratio of composite microcrystals to activated carbon was adjusted to 1:3, while other conditions remained unchanged. The copper concentration after treatment was 0.29 mg / L, and the copper removal rate was 97.1%. Under these conditions, the reduction of organic interferences in the supernatant was better, and the system showed higher stability.

[0065] As can be seen from Examples 2-4 above, the composite agent of the present invention has a good deep treatment capability for complexed copper wastewater, and can treat wastewater with an initial copper concentration of about 10 mg / L to below 0.5 mg / L, thus meeting the technical effect of deep copper removal at the end of the process.

[0066] Comparative Example 1: Blank Group

[0067] The simulated complexed copper wastewater from Example 2 was treated using deionized water instead of the Fenton-coagulant composite agent, following the wastewater treatment conditions of Example 2. The copper concentration after treatment was 9.8 mg / L, with a removal rate of 2.0%.

[0068] Comparative Example 2: Only unmodified activated carbon was added

[0069] Unmodified activated carbon was used to replace the Fenton-coagulant composite agent in Example 2. The activated carbon dosage was 1.0 g / L, and no Fenton component or PAM was added. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2. The copper concentration after treatment was 7.4 mg / L, and the removal rate was 26.0%.

[0070] Comparative Example 3: Traditional Fenton Group

[0071] According to the same Fe as in Example 2 2+ The wastewater was treated with H2O2, but without the addition of PAM or the loading onto activated carbon. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2. The copper concentration after treatment was 3.1 mg / L, with a removal rate of 69.0%.

[0072] Comparative Example 4: Fe 2+ +H2O2+PAM direct addition group

[0073] Ferrous salts, hydrogen peroxide, and PAM were directly added to the wastewater, but no composite microcrystals were prepared, nor was activated carbon embedded. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2. The copper concentration after treatment was 1.2 mg / L, and the removal rate was 88.0%.

[0074] Comparative Example 5: Simple physical mixture of composite microcrystals and activated carbon

[0075] The composite microcrystals and activated carbon from Example 2 were simply mixed and directly added without impregnation, loading, or embedding. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2. The copper concentration after treatment was 0.85 mg / L, with a removal rate of 91.5%.

[0076] Comparative Example 6: Conventional Alkali Precipitation Group

[0077] The wastewater pH was adjusted to around 10 before conventional sedimentation treatment. The copper concentration after treatment was 5.2 mg / L, with a removal rate of 48.0%.

[0078] The above results indicate that activated carbon alone has limited effectiveness in removing complexed copper; while the traditional Fenton system alone can achieve some degree of complex disruption, it lacks subsequent adsorption and flocculation synergy, resulting in a still high copper concentration in the effluent; Fe 2+ When H2O2 and PAM are simply added directly, the treatment effect is better than that of traditional Fenton, but still significantly weaker than that of the composite reagent of this invention. When the composite microcrystals are simply physically mixed with activated carbon, the treatment effect is still lower than that of the loaded embedded structure of this invention. Conventional alkaline precipitation method has poor effect on the removal of complexed copper. In contrast, this invention pre-constructs the Fenton reaction components, PAM and porous activated carbon into a composite system, so that the functional components work synergistically in the same treatment process, thus significantly reducing the copper concentration in the effluent and improving the removal rate and operational stability.

[0079] Example 5:

[0080] The dosage of the reagent in Example 2 was set to 0.2, 0.5, 1.0, 1.5, and 2.0 g / L, respectively. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2, and the copper concentrations after treatment were 4.3, 1.6, 0.36, 0.22, and 0.20 mg / L, respectively. The results showed that the copper removal effect significantly increased with increasing reagent dosage; however, after the dosage reached 1.0 g / L, further increases in dosage resulted in a smaller improvement in removal efficiency. Therefore, the preferred dosage is 1.0–1.5 g / L.

[0081] Example 6:

[0082] The initial pH values ​​in Example 2 were set to 3.0, 4.0, 5.0, 6.0, and 7.0, respectively. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2, resulting in copper concentrations of 0.78, 0.42, 0.36, 0.55, and 1.12 mg / L after treatment, respectively. The results show that within the pH range of 4.0–6.0, the system of this invention exhibits a good balance between complex-breaking oxidation capacity and flocculation sedimentation effect, with the best overall treatment effect observed at pH 5.0.

[0083] Example 7:

[0084] H2O2 / Fe in Example 2 2+ The molar ratios were set to 1:1, 2:1, 3:1, and 4:1, respectively, and the simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2. The copper concentrations after treatment were 1.35, 0.36, 0.24, and 0.31 mg / L, respectively. The results indicate that the H2O2 / Fe... 2+ The treatment effect is better when the molar ratio is 2:1 to 3:1.

[0085] Example 8:

[0086] The PAM dosages in Example 2, based on the iron salt mass, were 1%, 3%, 5%, 8%, and 10%, respectively. These were used to treat the simulated complexed copper wastewater from Example 2 under the same wastewater treatment conditions. The resulting copper concentrations were 1.08, 0.48, 0.36, 0.40, and 0.52 mg / L, respectively. The results indicate that when the PAM dosage is 3%–5%, the construction of the composite microcrystals and the subsequent flocculation and sedimentation effects are well-coordinated.

[0087] Example 9:

[0088] The mass ratios of composite microcrystals to activated carbon in Example 2 were set to 1:1, 1:2, 1:3, and 1:4, respectively. The simulated complexed copper wastewater from Example 2 was treated under the wastewater treatment conditions of Example 2, and the copper concentrations after treatment were 0.62, 0.36, 0.29, and 0.47 mg / L, respectively. The results show that when the mass ratio of composite microcrystals to activated carbon is 1:2 to 1:3, a good balance can be maintained between the loading of the oxidizing component and the adsorption effect.

[0089] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A Fenton-coagulant composite agent for deep copper removal from semiconductor wastewater, characterized in that: Composite microcrystals were prepared by using ferrous ions, hydrogen peroxide, and polyacrylamide. The composite microcrystals were then embedded into the pores of porous activated carbon to obtain a composite agent.

2. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 1, characterized in that: (1) Preparation of composite microcrystalline precursor Hydrogen peroxide solution was added to the ferrous salt solution under stirring conditions, and polyacrylamide solution was slowly added under low temperature conditions. After the polyacrylamide solution was added, aging or standing was continued to promote the formation of composite microcrystal precursors. (2) Loading and embedding of composite microcrystals in porous activated carbon The composite microcrystalline precursor obtained in step (1) is brought into contact with porous activated carbon, so that the composite microcrystalline is embedded in the pores of the activated carbon and attached to its surface and channels, thereby obtaining a composite agent.

3. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The ferrous salt is a soluble ferrous salt, selected from one or both of ferrous sulfate or ferrous chloride, preferably ferrous sulfate; Fe in the divalent iron salt solution 2+ The concentration is 0.02–0.10 mol / L, preferably 0.03–0.08 mol / L, and more preferably 0.05 mol / L.

4. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The mass fraction of the hydrogen peroxide is 20% to 35%, preferably 30%; The hydrogen peroxide and Fe 2+ The molar ratio is 1:1 to 4:1, preferably 1.5:1 to 3:1, and more preferably 2:1 to 3:

1.

5. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The polyacrylamide is anionic, nonionic, or weakly cationic polyacrylamide, preferably anionic polyacrylamide, and the mass fraction of the polyacrylamide solution is 0.05% to 0.30%, preferably 0.1% to 0.2%. The amount of polyacrylamide added is 1% to 10% of the mass of the divalent iron salt, preferably 3% to 8%, and more preferably 3% to 5%.

6. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: In step (1), the low temperature is 0-10℃, preferably 3-8℃, and more preferably 5℃; the stirring speed is 200-600 rpm, preferably 300-500 rpm; and the stirring time is 20-60 min, preferably 25-40 min, and more preferably 30 min. The aging or settling time is 0.5 to 2 hours, preferably 0.5 to 1.5 hours.

7. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The activated carbon is unmodified activated carbon, preferably one of wood-based activated carbon, coal-based activated carbon, or fruit shell activated carbon, with a particle size of 80-300 mesh, preferably 100-200 mesh.

8. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The mass ratio of the composite microcrystalline precursor to activated carbon is 1:1 to 1:4, preferably 1:1.5 to 1:3, and more preferably 1:2 to 1:

3.

9. The preparation method of the Fenton-coagulation composite agent for deep copper removal from semiconductor wastewater according to claim 2, characterized in that: The embedding in step (2) can be carried out by one or more of spray drying, impregnation drying or physical grinding embedding methods, preferably by a combination of impregnation drying and physical grinding embedding. The embedding conditions are 4–12 h, 50–70 °C, and drying for 8–12 h; preferably 6–10 h, 55–65 °C, and drying for 8–10 h; more preferably 8 h, 60 °C, and drying for 10 h.

10. The application of the Fenton-coagulant composite agent for deep copper removal from semiconductor wastewater according to any one of claims 2-9, characterized in that: Adjust the initial pH of the copper-containing semiconductor wastewater to be treated, add Fenton-coagulation composite agent to the wastewater at a dosage of 0.2–2.0 g / L, and react by coagulation and stirring after the agent is added. First, stir rapidly for 5–15 min at a speed of 150–300 rpm; then stir slowly for 10–20 min at a speed of 40–80 rpm. After the stirring reaction is completed, the wastewater is allowed to settle for 20-40 minutes. After settling, solid-liquid separation is carried out by gravity sedimentation, inclined plate sedimentation, filtration or centrifugation to remove the formed flocs and load carrier particles, and obtain low copper water.

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