A method for treating PCB nickel-containing wastewater based on ozone catalysis

Abstract

The application relates to the technical field of sewage treatment, and particularly discloses a PCB nickel-containing wastewater treatment method based on ozone catalysis. The PCB nickel-containing wastewater treatment method based on ozone catalysis comprises the following steps: step 1), wastewater is injected into an initial sedimentation tank, precipitation is carried out, upper water is taken out, filtered water is filtered out, and pretreated water is obtained; step 2), the pretreated water is introduced into a reaction tank, a composite catalyst and alkali are introduced into the reaction tank, continuous stirring is carried out, ozone is introduced, and stirring reaction is carried out for 3-5 hours, and reaction water is obtained; and step 3), the reaction water is introduced into a sedimentation tank, a flocculating agent is introduced, upper water is taken out, filtered water is filtered out, and clean water is obtained; the composite catalyst is a composite of acetylacetone iron, cuprous cyanide and zirconium silicate. The application has the advantage that nickel in nickel-containing wastewater can be better removed.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and in particular to a method for treating nickel-containing PCB wastewater based on ozone catalysis. Background Technology

[0002] Printed Circuit Boards (PCBs) are indispensable components in modern electronic products. They serve as the support for electronic components and the carrier for electrical connections. Almost every electronic device, from small items like electronic watches and calculators to large systems like automobiles, computers, 5G communication equipment, and military weapon systems, uses PCBs. my country's PCB industry has developed rapidly, with its total output value exceeding 50% of the global PCB industry's total output value. The Yangtze River Delta and Pearl River Delta regions alone account for approximately 90% of China's total PCB output value.

[0003] With the continuous development and expansion of the PCB industry, the wastewater problem generated during PCB production has become increasingly prominent. PCB manufacturing is a complex and highly integrated manufacturing technology with a long production process and many pollution-generating steps. PCB wastewater not only contains various heavy metals but also many toxic organic compounds such as cyanide, while ammonia nitrogen and total phosphorus levels exceed standards. To promote the healthy development of the PCB industry and to unify the supervision of environmental issues, the government has gradually incorporated PCB manufacturers into centralized management within industrial parks. The industrialization of PCB parks is becoming increasingly evident, with more companies operating within these parks, leading to a continuous increase in wastewater generated.

[0004] Nickel plating, as a commonly used surface treatment technology, is widely applied in various industries such as electronics, automotive, and machinery. The gold plating process in printed circuit board manufacturing uses either electroless or electroplating nickel plating. To ensure the stability, lifespan, and coating quality of the plating solution, electroless nickel plating solutions require the addition of large amounts of soluble nickel salts and hypophosphite, as well as complexing agents, accelerators, stabilizers, brighteners, and pH buffers. In electroless nickel plating solutions, the complexing agents used are mostly organic acids, such as citric acid. Nickel is classified as a pollutant, and regulations require that nickel-containing wastewater generated during nickel plating processes be collected, treated, and meet standards separately. Because the complexing agents in electroless nickel plating solutions contain various ligands, these ligands combine with nickel ions to form stable complexes. Conventional heavy metal hydroxide precipitation processes are insufficient to achieve stable compliance with nickel-containing wastewater treatment standards; therefore, there is room for improvement. Summary of the Invention

[0005] To better remove nickel from nickel-containing wastewater, this application provides a method for treating nickel-containing PCB wastewater based on ozone catalysis.

[0006] The ozone-catalyzed method for treating nickel-containing PCB wastewater provided in this application adopts the following technical solution:

[0007] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0008] Step 1): Inject wastewater into the primary sedimentation tank, allow it to settle, take the supernatant water, filter the water, and obtain pretreated water.

[0009] Step 2): Pretreated water is introduced into the reaction tank, composite catalyst and alkali are added to the reaction tank, and the mixture is stirred continuously. Ozone is introduced and the reaction is stirred for 3-5 hours to obtain reaction water.

[0010] Step 3): Flow the reaction water into the sedimentation tank, add flocculant, take the upper layer water, filter the water, and obtain clean water;

[0011] The composite catalyst is a mixture of iron acetylacetone, cuprous cyanide, and zirconium silicate.

[0012] By adopting the above technical solution, and using a composite catalyst composed of ferric acetylacetone, cuprous cyanide, and zirconium silicate in combination with ozone for catalytic oxidation, the nickel ion complexes in the wastewater are destroyed, allowing the nickel ions to react smoothly with the alkali to form a precipitate. This achieves a good removal effect of nickel ions, and the nickel ion concentration after wastewater treatment can reach ≤0.1mg / L, which well meets the discharge standards.

[0013] Preferably, the mass ratio of iron acetylacetonate, cuprous cyanide, and zirconium silicate is 12-14:9-11:17-19.

[0014] By adopting the above technical solution and specifically selecting the mass ratio of ferric acetylacetonate, cuprous cyanide, and zirconium silicate, the catalytic oxidation effect in combination with ozone is more significant, which can better remove nickel ions from wastewater and make the wastewater treatment effect better.

[0015] Preferably, the amount of composite catalyst added is 38-44 mg composite catalyst / 1 L wastewater.

[0016] By adopting the above technical solution and specifically selecting the amount of composite catalyst to be added, the effect of catalytic oxidation can be guaranteed while reducing raw material waste and better controlling costs, which has high economic value.

[0017] Preferably, the ozone injection rate is 65-75 mg ozone / L wastewater.

[0018] By adopting the above technical solution and specifically selecting the amount of ozone introduced, a better catalytic oxidation effect can be ensured, raw material waste can be reduced, and economic value can be further improved.

[0019] Preferably, the flocculant is a mixture of polyaluminum chloride and polyacrylamide.

[0020] By adopting the above technical solution and specifically selecting a combination of polyaluminum chloride and polyacrylamide as flocculants, the flocculation and sedimentation effect is better, resulting in better quality of treated water.

[0021] Preferably, the mass ratio of polyaluminum chloride to polyacrylamide is 1-2:1-2.

[0022] By adopting the above technical solution and specifically selecting the mass ratio of polyaluminum chloride and polyacrylamide, the effect of colloids capturing suspended solids is further improved, making the flocculation and sedimentation effect more significant and the wastewater treatment effect better.

[0023] Preferably, the dosage of the flocculant is 2-4 mg flocculant / 1 L wastewater.

[0024] By adopting the above technical solution and specifically selecting the amount of flocculant added, a better flocculation and sedimentation effect can be ensured, while reducing raw material waste and controlling costs.

[0025] Preferably, the alkali is sodium hydroxide.

[0026] By adopting the above technical solution and specifically selecting sodium hydroxide, the precipitation of nickel ions is better, and it is less likely to introduce new pollutants, resulting in better wastewater treatment.

[0027] In summary, this application has the following beneficial effects:

[0028] 1. Because this application uses a composite catalyst made of ferric acetylacetone, cuprous cyanide and zirconium silicate in combination with ozone for catalytic oxidation, the nickel ion complex in the wastewater is destroyed, allowing the nickel ions to react smoothly with the alkali to form a precipitate. This achieves a good removal effect of nickel ions, so that the nickel ion concentration after wastewater treatment can reach ≤0.1mg / L, which well meets the discharge standards.

[0029] 2. In this application, the preferred method is to select the specific mass ratio of ferric acetylacetone, cuprous cyanide, and zirconium silicate, which, when combined with ozone, results in a more significant catalytic oxidation effect, better removal of nickel ions from wastewater, and thus a better wastewater treatment effect.

[0030] 3. This application ensures the effectiveness of catalytic oxidation while reducing raw material waste and better controlling costs by specifically selecting the amount of composite catalyst and the amount of ozone introduced, thus having high economic value. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] Example 1

[0033] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0034] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0035] Step 2): 1000L of pretreated water is introduced into the reaction tank. 12g of ferric acetylacetone, 9g of cuprous cyanide, 17g of zirconium silicate, and 2kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 65g of ozone is introduced and stirred at 10r / min for 3 hours to obtain the reaction water.

[0036] Step 3) Pass the reaction water into the sedimentation tank, add 1g of polyaluminum chloride and 1g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0037] Iron acetylacetone was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0038] Cuprous cyanide was purchased from Hubei Dongcao Chemical Technology Co., Ltd.

[0039] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0040] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0041] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0042] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0043] Example 2

[0044] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0045] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0046] Step 2): 1000L of pretreated water is introduced into the reaction tank. 13g of ferric acetylacetone, 10g of cuprous cyanide, 18g of zirconium silicate, and 3kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 70g of ozone is introduced and stirred at 10r / min for 4 hours to obtain the reaction water.

[0047] Step 3) Pass the reaction water into the sedimentation tank, add 1.5g of polyaluminum chloride and 1.5g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0048] Iron acetylacetone was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0049] Cuprous cyanide was purchased from Hubei Dongcao Chemical Technology Co., Ltd.

[0050] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0051] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0052] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0053] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0054] Example 3

[0055] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0056] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0057] Step 2): 1000L of pretreated water is introduced into the reaction tank. 14g of ferric acetylacetone, 11g of cuprous cyanide, 19g of zirconium silicate, and 4kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 75g of ozone is introduced and stirred at 10r / min for 5 hours to obtain the reaction water.

[0058] Step 3) Pass the reaction water into the sedimentation tank, add 2g of polyaluminum chloride and 2g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0059] Iron acetylacetone was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0060] Cuprous cyanide was purchased from Hubei Dongcao Chemical Technology Co., Ltd.

[0061] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0062] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0063] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0064] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0065] Comparative Example 1

[0066] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0067] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0068] Step 2): 1000L of pretreated water is introduced into the reaction tank. 13g of ferrocene, 10g of cuprous cyanide, 18g of zirconium silicate and 3kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 70g of ozone is introduced and stirred at 10r / min for 4 hours to obtain the reaction water.

[0069] Step 3) Pass the reaction water into the sedimentation tank, add 1.5g of polyaluminum chloride and 1.5g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0070] Ferrocene was acquired by Jinan Shuangying Chemical Co., Ltd.

[0071] Cuprous cyanide was purchased from Hubei Dongcao Chemical Technology Co., Ltd.

[0072] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0073] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0074] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0075] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0076] Comparative Example 2

[0077] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0078] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0079] Step 2): 1000L of pretreated water is introduced into the reaction tank. 13g of acetylacetone iron, 10g of copper oxide, 18g of zirconium silicate and 3kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 70g of ozone is introduced and stirred at 10r / min for 4 hours to obtain the reaction water.

[0080] Step 3) Pass the reaction water into the sedimentation tank, add 1.5g of polyaluminum chloride and 1.5g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0081] Iron acetylacetone was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0082] Copper oxide was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0083] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0084] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0085] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0086] Comparative Example 3

[0087] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0088] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0089] Step 2): 1000L of pretreated water is introduced into the reaction tank. 13g of ferric acetylacetone, 10g of cuprous cyanide, 18g of cobalt carbonate, and 3kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 70g of ozone is introduced and stirred at 10r / min for 4 hours to obtain the reaction water.

[0090] Step 3) Pass the reaction water into the sedimentation tank, add 1.5g of polyaluminum chloride and 1.5g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0091] Iron acetylacetone was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0092] Cuprous cyanide was purchased from Hubei Dongcao Chemical Technology Co., Ltd.

[0093] Cobalt carbonate was purchased from Shandong Duoju Chemical Co., Ltd.

[0094] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0095] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0096] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0097] Comparative Example 4

[0098] A method for treating nickel-containing PCB wastewater based on ozone catalysis includes the following steps:

[0099] Step 1) Inject the wastewater into the primary sedimentation tank, let it stand for 2 hours to settle, take the upper layer of water, filter the water to obtain pretreated water.

[0100] Step 2): 1000L of pretreated water is introduced into the reaction tank. 13g of ferrocene, 10g of copper oxide, 18g of cobalt carbonate and 3kg of sodium hydroxide are added to the reaction tank. The mixture is stirred continuously at 10r / min. 70g of ozone is introduced and stirred at 10r / min for 4 hours to obtain the reaction water.

[0101] Step 3) Pass the reaction water into the sedimentation tank, add 1.5g of polyaluminum chloride and 1.5g of polyacrylamide, take the upper layer of water, filter the water through the filter cloth to obtain purified water.

[0102] Ferrocene was acquired by Jinan Shuangying Chemical Co., Ltd.

[0103] Copper oxide was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0104] Cobalt carbonate was purchased from Shandong Duoju Chemical Co., Ltd.

[0105] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0106] Polyaluminum chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0107] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0108] Experiment 1

[0109] All embodiments and comparative examples used the same batch of wastewater for the experiments.

[0110] The nickel ion content of the wastewater used in the experiment was specifically 18.456 mg / L.

[0111] The wastewater was treated using the ozone-catalyzed PCB nickel-containing wastewater treatment methods described in the various embodiments and comparative examples. The purified water obtained after treatment was tested, and the nickel ion content in the purified water of each embodiment and comparative example was recorded.

[0112] The experimental data are detailed in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] According to the data comparison of each embodiment and comparative example in Table 1, the nickel ion content in the purified water obtained in each embodiment is significantly lower than that in each comparative example. It can be seen that when using ozone catalytic oxidation to treat nickel-containing wastewater, the addition of a catalyst composed of ferric acetylacetone, cuprous cyanide and zirconium silicate can significantly improve the nickel ion removal rate, resulting in better wastewater treatment effect and purified water that can better meet the stringent discharge standards.

[0117] When other catalysts are used to replace iron acetylacetone, cuprous cyanide, and zirconium silicate in the examples, although there is still some effect in removing nickel ions, the effect is significantly reduced and it is difficult to meet the increasingly stringent emission standards.

[0118] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for treating nickel-containing PCB wastewater based on ozone catalysis, characterized in that: Includes the following steps: Step 1) Inject the wastewater into the primary sedimentation tank, allow it to settle, take the supernatant water, filter the water, and obtain pretreated water; Step 2): Pretreated water is introduced into the reaction tank. Composite catalyst and alkali are added to the reaction tank, and the mixture is stirred continuously. Ozone is introduced and the reaction is stirred for 3-5 hours to obtain reaction water. Step 3) Flow the reaction water into the sedimentation tank, add flocculant, take the upper layer water, filter the water, and obtain clean water; The composite catalyst is a mixture of iron acetylacetone, cuprous cyanide, and zirconium silicate. The mass ratio of ferric acetylacetonate, cuprous cyanide, and zirconium silicate is 12-14:9-11:17-19. The amount of the composite catalyst added is 38-44 mg of composite catalyst per 1 L of wastewater; The ozone injection rate is 65-75 mg ozone / L wastewater.

2. The method for treating nickel-containing PCB wastewater based on ozone catalysis according to claim 1, characterized in that: The flocculant is a mixture of polyaluminum chloride and polyacrylamide.

3. The method for treating nickel-containing PCB wastewater based on ozone catalysis according to claim 2, characterized in that: The mass ratio of polyaluminum chloride to polyacrylamide is 1-2:1-2.

4. The method for treating nickel-containing PCB wastewater based on ozone catalysis according to claim 3, characterized in that: The dosage of the flocculant is 2-4 mg flocculant / 1 L wastewater.

5. The method for treating nickel-containing PCB wastewater based on ozone catalysis according to claim 1, characterized in that: The alkali is sodium hydroxide.

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