Preparation method, product and application of Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater

Abstract

The application relates to a preparation method, product and application of a Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater. The Fe-based composite material is constructed by using the structural advantages of MOFs materials, the active metal components are stabilized by using the skeleton structure of ZIFs, the decomplexation and chelation of complex phosphorus are promoted, and the Fe-based material further forms insoluble ferric phosphate with the complex phosphorus, so that the efficient removal of total phosphorus is realized, the treatment cost of sludge is further reduced, and the resource treatment of total phosphorus in chemical nickel wastewater is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method, product and application of a Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater, which utilizes the Fe-based precipitant to promote the formation of insoluble iron phosphate, effectively removes total phosphorus and also realizes resource recycling, and is used in the field of electroplating wastewater treatment. BACKGROUND

[0002] With the development of electroplating industry, the pollution problem that follows is still an important link affecting the development of the industry. Electroplating wastewater mainly comes from cleaning of plated parts, floor washing, hanging tool and pole washing, etc., among which, the cleaning wastewater of plated parts is one of the main sources of electroplating wastewater, accounting for about 80% of the total amount of production wastewater, which not only consumes a large amount of water, but also produces complex types of wastewater. The treatment and recycling of electroplating wastewater play a crucial role in saving water resources and protecting the environment.

[0003] In recent years, electroless nickel plating (ENP) has become a widely used surface treatment technology due to its uniform coating, no need for external power supply, high hardness, good wear resistance, and no restriction on part shape. However, with the advancement of electroless plating process, nickel ions are gradually consumed, and by-products such as phosphite, sodium ions, and sulfate gradually accumulate, resulting in waste ENP (SENP) solution. SENP contains a large amount of complex nickel, hypophosphite, phosphite, and sulfate, as well as a small amount of complex, neutralizing agent / buffer, stabilizer, and whitening agent. On the one hand, the SENP solution contains toxic chemical elements, causing environmental problems; on the other hand, due to its complex composition, it is difficult to treat. Nickel and nickel compounds not only pose a serious threat to aquatic plants and animals, but also pose a serious threat to human health. Phosphorus can easily cause water eutrophication, leading to the outbreak of water bloom, blue-green algae, and red tide. On the other hand, nickel is a relatively expensive heavy metal resource, and phosphorus is a non-renewable resource. Therefore, according to the principles and goals of green chemistry, it is of great significance to adopt efficient treatment methods to realize the recovery and reuse of nickel and phosphorus, and the treated wastewater meets environmental protection requirements.

[0004] In electroless nickel plating, most of the nickel exists in the form of stable complexes, and phosphorus mainly exists in the form of hypophosphite and phosphite, which greatly affects the precipitation removal effect of nickel ions or phosphorus. Some studies have reported the use of Fenton oxidation process to oxidize hypophosphite and phosphite, but the oxidation efficiency is still low in actual treatment, and a large amount of sludge is generated, increasing the cost of sludge treatment. Chemical precipitation method consumes a large amount of chemical reagents, but it is commonly used, simple to operate, effective, and mature in technology, especially in treating high-concentration nickel and phosphorus, which is the preferred method for treating chemical nickel wastewater. SUMMARY

[0005] In view of the problems of low efficiency and high treatment cost of the Fenton oxidation process, a simple chemical precipitation method is used to quickly precipitate the complex nickel and form sludge for waste resource utilization, and the application aims to provide a preparation method of Fe-based composite precipitator for removing complex phosphorus in electroplating chemical nickel wastewater.

[0006] Another purpose of the application is to provide a Fe-based composite precipitator product for removing complex phosphorus in electroplating chemical nickel wastewater prepared by the above method.

[0007] Another purpose of the application is to provide an application of the above product.

[0008] The purpose of the application is achieved by the following scheme: a preparation method of Fe-based composite precipitator for removing complex phosphorus in electroplating chemical nickel wastewater, characterized by using Fe-based composite material to carry out decomplexation-chelation precipitation on the complex phosphorus in water to form iron phosphate precipitate, which can not only effectively reduce the total phosphorus content in water, but also can be reused as a resource, comprising the following steps:

[0009] (1) Under magnetic stirring, Fe(NO3)3.9H2O and Zn(NO3)2.6H2O are dissolved in N,N-dimethylformamide (DMF) according to a certain molar ratio, the molar ratio of Fe(NO3)3.9H2O and Zn(NO3)2.6H2O is 1: (5-30), and a certain proportion of metal nitrate is slowly added to the iron-zinc mixed solution, and the mixture is uniformly mixed to facilitate the synergistic effect between the various metals;

[0010] (2) A certain amount of dimethyl imidazole is dissolved in DMF according to a certain molar ratio of Zn to dimethyl imidazole ligand, then the mixed solution in (1) is added dropwise to the ligand solvent, and after the dropwise addition is completed, it is transferred to a polytetrafluoroethylene reaction container, and the reaction temperature and time are adjusted;

[0011] (3) After the reaction is completed and the temperature is lowered to room temperature, the precipitate is collected by centrifugation, and washed and freeze-dried to obtain the ZIFs precursor;

[0012] (4) The product in (3) is placed in a tube furnace for calcination treatment, the calcination atmosphere is controlled to be 5% H2 / Ar2 or N2, and the calcination temperature and time are controlled, and the Fe-based composite precipitator is obtained.

[0013] In step (1), the metal nitrate is one or two of manganese nitrate, copper nitrate and cobalt nitrate.

[0014] Preferably, in step (2), the molar ratio of Zn(NO3)2.6H2O to dimethyl imidazole ligand is 1:(5-8), and the reaction is carried out at 80-120 DEG C for 4-10 h.

[0015] In step (2), the calcination temperature is 500-900 DEG C, and the calcination is carried out for 2-6 h.

[0016] The application also provides a Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater, which is prepared according to any of the above methods.

[0017] The application also provides a use of the Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater.

[0018] The application can make the complex phosphorus decomplexing by synthesizing a Fe-based composite precipitant, and the Fe-based composite precipitant can be coordinated with Fe ions, and the Fe-based composite precipitant can be converted into a relatively stable iron phosphate precipitate by adjusting pH, and the Fe-based composite precipitant can not only solve the problem of total phosphorus removal, but also can realize the reuse of non-renewable resource phosphorus, and has good practical significance.

[0019] The phosphorus removal experiment of the Fe-based composite precipitant is carried out in a beaker, a certain amount of the above-mentioned precipitant is dispersed into a certain amount of DMF solvent, and the Fe-based composite precipitant solution is prepared, and the pH of the system is adjusted to about 3-4. 0.5 mL of the Fe-based composite precipitant solution is added to 50 mL of the chemical nickel wastewater (total phosphorus = 49 mg / L) according to the volume ratio of 1:100, and after stirring for 2 min, the upper layer is separated, and the supernatant is taken to determine the removal rate of total phosphorus in the electroplating chemical nickel wastewater.

[0020] The application has the following advantages:

[0021] (1) The application uses ZIF precursor as a sacrificial precursor, and through one-step high-temperature pyrolysis, the metal-organic skeleton structure of the ZIF precursor is well preserved, and the mesoporous structure with a large specific surface area is beneficial to the mass transfer and diffusion of reactants. On this basis, the Zn left after the pyrolysis of ZIF-8 can effectively fix the active metal and improve the structural stability of the Fe-based composite precipitant.

[0022] (2) The Fe-based composite precipitant prepared by the application can accelerate the decomplexing and precipitation of complex hypophosphite through the synergistic effect of multiple metals, and promote the rapid removal of total phosphorus.

[0023] (3) The preparation method of the Fe-based composite precipitant proposed by the application is simple and controllable, and the phosphorus removal process can effectively reduce the treatment cost of sludge and promote the resource utilization, and has potential application prospect in the field of environmental governance. DETAILED DESCRIPTION

[0024] The application is further illustrated by examples.

[0025] Example 1:

[0026] A Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater, which utilizes Fe-based composite material to carry out decomplexation-chelation precipitation on complex phosphorus in water to form iron phosphate precipitate, can not only effectively reduce the total phosphorus content in water, but also can recycle the iron phosphate as a resource, and is prepared according to the following steps:

[0027] (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) according to a molar ratio of 1:5 to obtain a zinc-iron mixed solution; a certain proportion of manganese nitrate and copper nitrate is slowly added to the zinc-iron mixed solution, and the mixture is uniformly mixed;

[0028] (2) Dimethylimidazole is weighed according to a molar ratio of 1:8 of Zn to dimethylimidazole ligand, and is dissolved in DMF to obtain a ligand solvent; then the mixed solution obtained in (1) is added dropwise to the ligand solvent, and after the dropwise addition is completed, the mixture is transferred to a polytetrafluoroethylene reaction container, the reaction temperature is adjusted to 120 ℃, and the reaction is carried out for 10 h;

[0029] (3) After the reaction is completed and the temperature is lowered to room temperature, the precipitate is collected by centrifugation, and is washed and freeze-dried to obtain a ZIFs precursor;

[0030] (4) The ZIFs precursor product in (3) is placed in a tube furnace for calcination treatment, the calcination atmosphere is controlled to be 5% H2 / Ar2, and the calcination is carried out at 800 ℃ for 4 h to obtain the Fe-based composite precipitant.

[0031] The prepared precipitant can remove 95.3% of the total phosphorus in the chemical nickel wastewater.

[0032] Example 2:

[0033] A Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater, which is similar to the steps in Example 1, and is prepared according to the following steps:

[0034] (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) according to a molar ratio of 1:10, and a certain proportion of manganese nitrate and copper nitrate is slowly added thereto, and the mixture is uniformly mixed;

[0035] (2) According to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:6, a certain amount of dimethyl imidazole was weighed and dissolved in DMF, then the mixed solution in (1) was added dropwise into the ligand solvent, and after the dropwise addition was completed, it was transferred to a polytetrafluoroethylene reaction container, and the reaction temperature and time were adjusted to 120°C and 10h, respectively;

[0036] (3) After the reaction was completed and cooled to room temperature, the precipitate was collected by centrifugation, and washed, freeze-dried to obtain a ZIFs precursor;

[0037] (4) The product in (3) was placed in a tube furnace for calcination treatment, the calcination atmosphere was controlled to be 5%H2 / Ar, and the calcination was carried out at 800°C for 2h to obtain a Fe-based composite precipitator.

[0038] The prepared precipitator can remove 94.5% of total phosphorus in chemical nickel wastewater treatment.

[0039] Example 3:

[0040] A Fe-based composite precipitator for removing complex phosphorus in electroplating chemical nickel wastewater was prepared according to the following steps similar to the steps of Example 1:

[0041] (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O were dissolved in N,N-dimethylformamide (DMF) according to the molar ratio of 1:30, and a certain proportion of copper nitrate was slowly added thereto, and the mixture was uniformly mixed;

[0042] (2) According to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:8, dimethyl imidazole was weighed and dissolved in DMF, then the mixed solution obtained in step (1) was added dropwise into the ligand solvent, and after the dropwise addition was completed, it was transferred to a polytetrafluoroethylene reaction container, and the reaction temperature was adjusted to 110°C, and the reaction was carried out for 6h;

[0043] (3) After the reaction was completed and cooled to room temperature, the precipitate was collected by centrifugation, and washed, freeze-dried to obtain a ZIFs precursor;

[0044] (4) The product in (3) was placed in a tube furnace for calcination treatment, the calcination atmosphere was controlled to be 5%H2 / Ar, and the calcination was carried out at 900°C for 2h to obtain a Fe-based composite precipitator.

[0045] The prepared precipitator can remove 90.8% of total phosphorus in chemical nickel wastewater treatment.

[0046] Example 4:

[0047] A kind of Fe-based composite precipitant for removing complex phosphorus in electroplating chemical nickel wastewater, which is prepared according to the following steps:

[0048] (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) according to the molar ratio of 1:20, and a certain proportion of manganese nitrate is slowly added, and mixed uniformly;

[0049] (2) Dimethyl imidazole is dissolved in DMF according to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:8, then the mixed solution obtained in step (1) is added dropwise into the ligand solvent, after the dropwise addition is completed, it is transferred to a polytetrafluoroethylene reaction container, the reaction temperature is adjusted to 80℃, and the reaction is carried out for 10h;

[0050] (3) After the reaction is completed and the temperature is lowered to room temperature, the precipitate is collected by centrifugation, and then washed and freeze-dried to obtain the ZIFs precursor;

[0051] (4) The product in (3) is placed in a tube furnace for calcination treatment, the calcination atmosphere is controlled to be N2, and the calcination is carried out at 800℃ for 2h, and then the Fe-based composite precipitant is obtained.

[0052] The removal rate of total phosphorus in the prepared precipitant in the treatment of chemical nickel wastewater can reach 84.9%.

Claims

1. Use of a Fe-based composite precipitant for removing phosphorus complexed in electroplating chemical nickel wastewater, characterized in that, The Fe-based composite precipitant accelerates the decomplexation and precipitation of the complexed hypophosphite through the synergistic effect of multiple metals, promotes the rapid removal of total phosphorus, and comprises the following preparation steps: (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF), and the molar ratio of Fe(NO3)3·9H2O to Zn(NO3)2·6H2O is 1: (5-30), to obtain a zinc-iron mixed solution; a certain proportion of metal nitrate is slowly added to the zinc-iron mixed solution and mixed uniformly; (2) Dimethylimidazole is weighed according to the molar ratio of Zn to dimethylimidazole ligand, dissolved in DMF to obtain a ligand solvent; then the mixed solution obtained in (1) is added dropwise into the ligand solvent, and after the dropwise addition is completed, it is transferred to a polytetrafluoroethylene reaction container, and the reaction is carried out at 80-120 ℃ for 4-10 h; (3) After the reaction is completed and the temperature is lowered to room temperature, the precipitate is collected by centrifugation, washed, and freeze-dried to obtain a ZIFs precursor; (4) The ZIFs precursor product in (3) is placed in a tube furnace for calcination treatment, the calcination atmosphere is controlled to be N2 or Ar containing 5% H2, and the calcination is carried out at 500-900 ℃ for 2-6 h to obtain a Fe-based composite precipitant. In step (1), the metal nitrate is one or two of manganese nitrate, copper nitrate, and cobalt nitrate.

2. Use according to claim 1, characterized in that, In step (2), the molar ratio of Zn(NO3)2·6H2O to dimethylimidazole ligand is 1: (5-8).

3. Use according to any one of claims 1 to 2, characterized in that, Prepared according to the following steps: Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) according to a molar ratio of 1:5 to obtain a zinc-iron mixed solution; a certain proportion of manganese nitrate and copper nitrate is slowly added to the zinc-iron mixed solution and mixed uniformly; (2) Dimethylimidazole is weighed according to the molar ratio of Zn to dimethylimidazole ligand, dissolved in DMF to obtain a ligand solvent; then the mixed solution obtained in (1) is added dropwise into the ligand solvent, and after the dropwise addition is completed, it is transferred to a polytetrafluoroethylene reaction container, and the reaction temperature is adjusted to 120 ℃, and the reaction is carried out for 10 h; (3) After the reaction is completed and the temperature is lowered to room temperature, the precipitate is collected by centrifugation, washed, and freeze-dried to obtain a ZIFs precursor; (4) The ZIFs precursor product in (3) is placed in a tube furnace for calcination treatment, the calcination atmosphere is controlled to be N2 or Ar containing 5% H2, and the calcination is carried out at 500-900 ℃ for 2-6 h to obtain a Fe-based composite precipitant.

4. Use according to any one of claims 1 to 2, characterized in that, Prepared according to the following steps: (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) according to a molar ratio of 1:10, and a certain proportion of manganese nitrate and copper nitrate is slowly added thereto and mixed uniformly; (2) A certain amount of dimethyl imidazole was weighed according to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:6, dissolved in DMF, then the mixed solution in (1) was added dropwise into the ligand solvent, and after the dropwise addition was completed, it was transferred into a polytetrafluoroethylene reaction container, and the reaction temperature and time were adjusted to 120°C and 10h, respectively; (3) After the reaction was completed and cooled to room temperature, the precipitate was collected by centrifugation, washed, and freeze-dried to obtain a ZIF precursor; (4) The product in (3) was placed in a tube furnace for calcination treatment, the calcination atmosphere was controlled to be 5% H2-containing Ar, and the calcination was carried out at 800°C for 2h to obtain a Fe-based composite precipitator.

5. Use according to any one of claims 1 to 2, characterized in that, Prepared according to the following steps: (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O were dissolved in N,N-dimethylformamide (DMF) according to the molar ratio of 1:30, and a certain proportion of copper nitrate was slowly added thereto, and the mixture was uniformly mixed; (2) Dimethyl imidazole was weighed according to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:8, dissolved in DMF, then the mixed solution obtained in step (1) was added dropwise into the ligand solvent, and after the dropwise addition was completed, it was transferred into a polytetrafluoroethylene reaction container, and the reaction temperature was adjusted to 110°C, and the reaction was carried out for 6h; (3) After the reaction was completed and cooled to room temperature, the precipitate was collected by centrifugation, washed, and freeze-dried to obtain a ZIF precursor; (4) The product in (3) was placed in a tube furnace for calcination treatment, the calcination atmosphere was controlled to be 5% H2-containing Ar, and the calcination was carried out at 900°C for 2h to obtain a Fe-based composite precipitator.

6. Use according to any one of claims 1 to 2, characterized in that, Prepared according to the following steps: (1) Under magnetic stirring, Fe(NO3)3·9H2O and Zn(NO3)2·6H2O were dissolved in N,N-dimethylformamide (DMF) according to the molar ratio of 1:20, and a certain proportion of manganese nitrate was slowly added thereto, and the mixture was uniformly mixed; (2) Dimethyl imidazole was weighed according to the molar ratio of Zn(NO3)2·6H2O to dimethyl imidazole ligand of 1:8, dissolved in DMF, then the mixed solution obtained in step (1) was added dropwise into the ligand solvent, and after the dropwise addition was completed, it was transferred into a polytetrafluoroethylene reaction container, and the reaction temperature was adjusted to 80°C, and the reaction was carried out for 10h; (3) After the reaction was completed and cooled to room temperature, the precipitate was collected by centrifugation, washed, and freeze-dried to obtain a ZIF precursor; (4) The product in (3) was placed in a tube furnace for calcination treatment, the calcination atmosphere was controlled to be N2, and the calcination was carried out at 800°C for 2h to obtain a Fe-based composite precipitator.