PCB nickel-containing wastewater treatment method based on ozone catalysis

Abstract

The invention 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), injecting wastewater into a primary sedimentation tank, precipitating, taking upper-layer water, and filtering effluent to obtain pretreated water; (2) introducing the pretreated water into a reaction tank, adding a composite catalyst and alkali into the reaction tank, continuously stirring, introducing ozone, and stirring to react for 3-5 hours to obtain reaction water; 3, the reaction water flows into a sedimentation tank, a flocculating agent is put into the sedimentation tank, upper-layer water is taken, effluent is filtered, and purified water is obtained.The composite catalyst is a compound of ferric acetylacetonate, cuprous cyanide and zirconium silicate.The method has the advantage that nickel in the nickel-containing wastewater can be better removed.

Description

Technical Field

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

[0002] Printed Circuit Board (PCB) is an indispensable component in modern electronic products. It is the support of electronic components and the carrier of electrical connection. Almost every electronic device, from electronic watches and calculators to cars, computers, 5G communication equipment, and military weapon systems, uses PCB. my country's PCB industry has developed rapidly, and its total output value has exceeded the global PCB industry's total output value by more than 50%, while the PCB output value of the Yangtze River Delta and the Pearl River Delta regions has reached about 90% of China's total output value.

[0003] With the continuous development and growth of the PCB industry, the problem of wastewater generated during PCB production has become increasingly prominent. PCB manufacturing is a complex and cumbersome, highly comprehensive manufacturing technology with a long production process and many polluting steps. PCB wastewater contains not only a variety of heavy metals, but also many toxic organic substances such as cyanide, and the ammonia nitrogen and total phosphorus in the water exceed the standard. In order to promote the healthy development of the PCB industry and to unify the supervision of environmental protection issues, the government has gradually integrated PCB production enterprises into the centralized management of industrial parks. The parkization of the PCB industry has become increasingly obvious, the number of enterprises in the park has increased, and the wastewater generated by PCB parks has continued to increase.

[0004] Nickel plating is a commonly used surface treatment technology and is widely used in electronics, automobiles, machinery and other industries. The gold plating process in the printed circuit board process uses chemical nickel plating or electroplating nickel. In order to ensure the stability, service life and coating quality of the plating solution, in addition to a large amount of soluble nickel salts and hypophosphites, a large amount of chelating agents, accelerators, stabilizers, brighteners and pH buffers need to be added to the chemical nickel plating solution. In the chemical nickel plating solution, the chelating agents used are mostly organic acids, such as citric acid. Nickel belongs to a class of pollutants, and regulations require that nickel-containing wastewater generated in the nickel plating process be collected, treated and meet standards separately. Since the chelating agent in the chemical nickel plating solution contains a variety of ligands, these ligands combine with nickel ions to form stable complexes. It is difficult to achieve stable treatment of nickel-containing wastewater to meet standards using conventional heavy metal hydroxide precipitation processes. Therefore, there is still room for improvement. Summary of the invention

[0005] In order to better remove nickel from nickel-containing wastewater, the present application provides a method for treating PCB nickel-containing wastewater based on ozone catalysis.

[0006] The present application provides a method for treating PCB nickel-containing wastewater based on ozone catalysis, which adopts the following technical solution: A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), injecting the wastewater into the primary sedimentation tank, settling, taking the upper layer of water, filtering the water, and obtaining pretreated water; Step 2), the pretreated water is passed into a reaction tank, a composite catalyst and a base are added into the reaction tank, the mixture is continuously stirred, ozone is passed into the reaction tank, and the mixture is stirred for reaction for 3-5 hours to obtain reaction water; Step 3), the reaction water flows into a sedimentation tank, a flocculant is added, the upper layer of water is taken, and the water is filtered to obtain purified water; The composite catalyst is a compound of ferric acetylacetonate, cuprous cyanide and zirconium silicate.

[0007] By adopting the above technical scheme, a composite catalyst composed of ferric acetylacetonate, cuprous cyanide and zirconium silicate is used in combination with ozone for catalytic oxidation, so that the nickel ion complex in the wastewater is destroyed, and the nickel ions can react smoothly with the alkali to form a precipitate, which can achieve a good effect of removing nickel ions. After the sewage is treated, the nickel ion concentration can reach ≤0.1 mg / L, which well meets the emission standards.

[0008] Preferably, the mass ratio of ferric acetylacetonate, cuprous cyanide and zirconium silicate is 12-14:9-11:17-19.

[0009] By adopting the above technical scheme, by specifically selecting the mass ratio of ferric acetylacetonate, cuprous cyanide and zirconium silicate, the effect of catalytic oxidation in combination with ozone is more significant, and nickel ions in sewage can be better removed, resulting in better sewage treatment effect.

[0010] Preferably, the input amount of the composite catalyst is 38-44 mg composite catalyst / 1 L wastewater.

[0011] By adopting the above technical solution and specifically selecting the input amount of the composite catalyst, the catalytic oxidation effect can be ensured while reducing the waste of raw materials, thus better controlling the cost and having a higher economic value.

[0012] Preferably, the amount of ozone introduced is 65-75 mg ozone / 1 L of wastewater.

[0013] By adopting the above technical solution and specifically selecting the amount of ozone introduced, a better catalytic oxidation effect can be ensured, and the waste of raw materials can be reduced, which can further improve the economic value.

[0014] Preferably, the flocculant is a compound of polyaluminium chloride and polyacrylamide.

[0015] By adopting the above technical solution and specifically selecting a flocculant as a compound of polyaluminium chloride and polyacrylamide, the flocculation and sedimentation effect is better, thereby improving the quality of the treated purified water.

[0016] Preferably, the mass ratio of the polyaluminium chloride to the polyacrylamide is 1-2:1-2.

[0017] By adopting the above technical solution and specifically selecting the mass ratio of polyaluminium chloride and polyacrylamide, the effect of colloid in capturing suspended solids can be further improved, the effect of flocculation and sedimentation can be more significant, and the sewage treatment effect can be better.

[0018] Preferably, the input amount of the flocculant is 2-4 mg flocculant / 1 L of wastewater.

[0019] By adopting the above technical solution and specifically selecting the input amount of flocculant, a better flocculation and sedimentation effect can be ensured, and the waste of raw materials can be reduced and the cost can be controlled.

[0020] Preferably, the base is sodium hydroxide.

[0021] By adopting the above technical solution and specifically selecting sodium hydroxide, the effect of nickel ion precipitation is better, and it is not easy to introduce new pollutants, so the sewage treatment effect is better.

[0022] In summary, this application has the following beneficial effects: 1. Since the present application adopts a composite catalyst composed of ferric acetylacetonate, cuprous cyanide and zirconium silicate in combination with ozone for catalytic oxidation, the nickel ion complex in the wastewater is destroyed, so that the nickel ions can react smoothly with the alkali to form a precipitate, and a good effect of removing nickel ions can be achieved. After the sewage is treated, the nickel ion concentration can reach ≤0.1 mg / L, which meets the emission standards very well.

[0023] 2. In the present application, it is preferred to specifically select the mass ratio of ferric acetylacetonate, cuprous cyanide and zirconium silicate, and the effect of catalytic oxidation in combination with ozone is more significant, which can better remove nickel ions in sewage and make the sewage treatment effect better.

[0024] 3. This application ensures the effect of catalytic oxidation while reducing the waste of raw materials, better controlling costs, and having high economic value by specifically selecting the input amount of the composite catalyst and the introduction amount of ozone. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the embodiments.

[0026] Example 1 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0027] Step 2), 1000L of pretreated water is passed into the reaction tank, 12g of ferric acetylacetonate, 9g of cuprous cyanide, 17g of zirconium silicate, and 2kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, and stirring is continued. 65g of ozone is passed into the reaction tank at a speed of 10r / min, and the reaction is stirred for 3h to obtain reaction water.

[0028] Step 3), the reaction water is passed into a sedimentation tank, 1g of polyaluminium chloride and 1g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0029] Ferric acetylacetonate was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0030] Cuprous cyanide was purchased from Hubei Tosoh Chemical Technology Co., Ltd.

[0031] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0032] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0033] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0034] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0035] Example 2 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0036] Step 2), 1000L of pretreated water is passed into the reaction tank, 13g of ferric acetylacetonate, 10g of cuprous cyanide, 18g of zirconium silicate, and 3kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, and stirring is continued. 70g of ozone is passed, the speed is 10r / min, and the reaction is stirred for 4h to obtain reaction water.

[0037] Step 3), the reaction water is passed into a sedimentation tank, 1.5 g of polyaluminium chloride and 1.5 g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0038] Ferric acetylacetonate was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0039] Cuprous cyanide was purchased from Hubei Tosoh Chemical Technology Co., Ltd.

[0040] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0041] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0042] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0043] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0044] Example 3 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0045] Step 2), 1000L of pretreated water is passed into the reaction tank, 14g of ferric acetylacetonate, 11g of cuprous cyanide, 19g of zirconium silicate, and 4kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, stirring is continued, 75g of ozone is passed, the speed is 10r / min, stirring and reacting for 5h, and reaction water is obtained.

[0046] Step 3), the reaction water is passed into a sedimentation tank, 2g of polyaluminium chloride and 2g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0047] Ferric acetylacetonate was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0048] Cuprous cyanide was purchased from Hubei Tosoh Chemical Technology Co., Ltd.

[0049] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0050] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0051] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0052] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0053] Comparative Example 1 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0054] Step 2), 1000L of pretreated water is passed into the reaction tank, 13g of ferrocene, 10g of cuprous cyanide, 18g of zirconium silicate, and 3kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, and stirring is continued. 70g of ozone is passed, the speed is 10r / min, and the reaction is stirred for 4h to obtain reaction water.

[0055] Step 3), the reaction water is passed into a sedimentation tank, 1.5 g of polyaluminium chloride and 1.5 g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0056] Ferrocene was purchased from Jinan Shuangying Chemical Co., Ltd.

[0057] Cuprous cyanide was purchased from Hubei Tosoh Chemical Technology Co., Ltd.

[0058] Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0059] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0060] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0061] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0062] Comparative Example 2 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0063] Step 2), 1000L of pretreated water is passed into the reaction tank, 13g of ferric acetylacetonate, 10g of copper oxide, 18g of zirconium silicate, and 3kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, and stirring is continued. 70g of ozone is passed, the speed is 10r / min, and the reaction is stirred for 4h to obtain reaction water.

[0064] Step 3), the reaction water is passed into a sedimentation tank, 1.5 g of polyaluminium chloride and 1.5 g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0065] Ferric acetylacetonate was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0066] Copper oxide was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. Zirconium silicate was purchased from Jining Juji New Materials Co., Ltd.

[0067] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0068] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0069] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0070] Comparative Example 3 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0071] Step 2), 1000L of pretreated water is passed into the reaction tank, 13g of ferric acetylacetonate, 10g of cuprous cyanide, 18g of cobalt carbonate, and 3kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, stirring is continued, 70g of ozone is passed, the speed is 10r / min, stirring and reacting for 4h to obtain reaction water.

[0072] Step 3), the reaction water is passed into a sedimentation tank, 1.5 g of polyaluminium chloride and 1.5 g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0073] Ferric acetylacetonate was purchased from Shandong Jinshengtai Chemical Co., Ltd.

[0074] Cuprous cyanide was purchased from Hubei Tosoh Chemical Technology Co., Ltd.

[0075] Cobalt carbonate was purchased from Shandong Poly Chemical Co., Ltd.

[0076] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0077] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0078] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0079] Comparative Example 4 A method for treating PCB nickel-containing wastewater based on ozone catalysis comprises the following steps: Step 1), inject the wastewater into the primary sedimentation tank, let it settle for 2 hours, take the upper layer of water, filter the water, and obtain pretreated water.

[0080] Step 2), 1000L of pretreated water is passed into the reaction tank, 13g of ferrocene, 10g of copper oxide, 18g of cobalt carbonate, and 3kg of sodium hydroxide are added into the reaction tank, the speed is 10r / min, and stirring is continued. 70g of ozone is passed, the speed is 10r / min, and the reaction is stirred for 4h to obtain reaction water.

[0081] Step 3), the reaction water is passed into a sedimentation tank, 1.5 g of polyaluminium chloride and 1.5 g of polyacrylamide are added, the upper layer of water is taken, and the water is filtered through a filter cloth to obtain clean water.

[0082] Ferrocene was purchased from Jinan Shuangying Chemical Co., Ltd.

[0083] Copper oxide was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0084] Cobalt carbonate was purchased from Shandong Poly Chemical Co., Ltd.

[0085] Sodium hydroxide was purchased from Shandong Haochen New Material Technology Co., Ltd.

[0086] Polyaluminium chloride was purchased from Gongyi Hongyuan Environmental Protection Technology Co., Ltd.

[0087] Polyacrylamide was purchased from Beijing Shouhua Zhongyan Environmental Protection Technology Co., Ltd.

[0088] Experiment 1 The same batch of wastewater was used for the experiments in various embodiments and comparative examples.

[0089] The nickel ion content of the wastewater used in the experiment was specifically 18.456 mg / L.

[0090] This batch of wastewater was treated using the ozone-catalyzed PCB nickel-containing wastewater treatment method of each embodiment and comparative example. The purified water obtained after the treatment was tested, and the nickel ion content in the purified water of each embodiment and comparative example was recorded.

[0091] The experimental data are shown in Table 1.

[0092] Table 1 According to the data comparison of each embodiment and the 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 the nickel-containing wastewater is treated by ozone catalytic oxidation, the nickel ion removal rate can be significantly improved by adding a catalyst composed of ferric acetylacetonate, cuprous cyanide and zirconium silicate, so that the sewage treatment effect is better, and the purified water obtained can better meet the strict emission standards.

[0093] When other catalysts are used to replace ferrous acetylacetonate, cuprous cyanide, and zirconium silicate in the examples alone or in combination, although there is a certain effect of removing nickel ions, the effect is significantly reduced, making it difficult to meet the requirements of increasingly stringent emission standards.

[0094] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for treating PCB nickel-containing wastewater based on ozone catalysis, characterized in that: The following steps are involved: Step 1), inject the wastewater into the primary sedimentation tank, precipitate, take the upper layer of water, filter the water, and obtain pretreated water; Step 2), the pretreated water is passed into the reaction tank, a composite catalyst and a base are added into the reaction tank, the mixture is continuously stirred, ozone is passed into the reaction tank, and the mixture is stirred for reaction for 3-5 hours to obtain reaction water; Step 3), the reaction water flows into the sedimentation tank, a flocculant is added, the upper layer of water is taken, and the water is filtered to obtain purified water; The composite catalyst is a compound of ferric acetylacetonate, cuprous cyanide and zirconium silicate.

2. The method for treating PCB nickel-containing wastewater based on ozone catalysis according to claim 1, characterized in that: The mass ratio of the ferric acetylacetonate, cuprous cyanide and zirconium silicate is 12-14:9-11:17-19.

3. The method for treating PCB nickel-containing wastewater based on ozone catalysis according to claim 2, characterized in that: The input amount of the composite catalyst is 38-44 mg composite catalyst / 1 L wastewater.

4. The method for treating PCB nickel-containing wastewater based on ozone catalysis according to claim 3, characterized in that: The amount of ozone introduced is 65-75 mg ozone / 1 L of wastewater.

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

6. The method for treating PCB nickel-containing wastewater based on ozone catalysis according to claim 5, characterized in that: The mass ratio of the polyaluminium chloride to the polyacrylamide is 1-2:1-2.

7. The method for treating PCB nickel-containing wastewater based on ozone catalysis according to claim 6, characterized in that: The input amount of the flocculant is 2-4 mg flocculant / 1 L of wastewater.

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

Images