A method for efficiently separating nickel, hypophosphorous acid and ammonia from electroless nickel plating waste liquid

Abstract

The present application relates to waste liquid treatment technical field, specifically to a kind of from chemical nickel plating waste liquid high-efficiency separation nickel, hypophosphorous acid and ammonia method, comprising the following steps: S1, nanofiltration: using roll nanofiltration membrane to chemical nickel plating waste water is nanofiltration separation, obtain containing nickel waste water, containing hypophosphorous acid and ammonia waste water;S2, bipolar membrane electrodialysis: the arrangement mode of bipolar membrane electrodialysis system is set to: the anode, first bipolar membrane, anion membrane, cation membrane, second bipolar membrane, cathode are sequentially arranged, containing hypophosphorous acid and ammonia waste water is passed into desalination room, deionized water is added in the acid room and base room, obtain hypophosphorous acid solution and ammonia gas;Then realize the separation of hypophosphorous acid and ammonia;The hypophosphite in the present application, ammonium in chemical nickel plating waste liquid is efficiently separated, and it is important to improve the phosphorus, ammonia resource utilization efficiency in chemical nickel plating waste liquid, reduce chemical nickel plating waste liquid processing difficulty and processing cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste liquid treatment, in particular to a method for efficiently separating nickel, hypophosphorous acid and ammonia from chemical nickel plating waste liquid. BACKGROUND

[0002] The chemical nickel plating waste liquid is complex in composition, containing not only heavy metal organic complex such as EDTA-Ni and nickel citrate, but also monovalent ions such as hypophosphite and ammonia. At present, the Fenton oxidation method is mainly used for treating chemical nickel plating waste liquid and waste water, and a large amount of sludge is generated, and the resources of hypophosphorus and ammonia are seriously wasted. If the hypophosphite and ammonium in the chemical nickel plating waste liquid are efficiently separated, it is of great significance to improve the resource utilization efficiency of phosphorus and ammonia in the chemical nickel plating waste liquid, and to reduce the difficulty and cost of treating the chemical nickel plating waste liquid.

[0003] Nanofiltration (NF) is a pressure-driven membrane technology between ultrafiltration and reverse osmosis. Because of its appropriate membrane pore size (usually between 0.5-1 nm) and charge repulsion mechanism, nanofiltration membranes can effectively retain macromolecular organic substances (>150 Da) and multivalent ions, while allowing monovalent ions (NH4 + , NO3 - , H2PO2 - ) to pass through. This selectivity makes nanofiltration membranes have good prospects in separating EDTA-Ni from other components in chemical nickel plating wastewater.

[0004] Bipolar membrane electrodialysis (BMED) is an advanced membrane separation technology that can separate anions and cations in wastewater without using chemical reagents, and generate corresponding acids and bases through the action of an electric field. This technology has a significant advantage in efficiently separating molecules such as ammonium (NH4 + ) and hypophosphite (H2PO2 - ) in waste water.

[0005] Therefore, the present application designs a method for efficiently separating nickel, hypophosphorous acid and ammonia from chemical nickel plating waste liquid to combine nanofiltration membranes and electrodialysis technology to improve separation efficiency. SUMMARY

[0006] In order to solve the above problems, the present application provides a method for efficiently separating nickel, hypophosphorous acid and ammonia from chemical nickel plating waste liquid.

[0007] A method for efficiently separating nickel, hypophosphorous acid and ammonia from chemical nickel plating waste liquid, comprising the following steps:

[0008] S1, nanofiltration:

[0009] First, the pH of the electroless nickel plating waste liquid is adjusted to 5-6, then 0.8-1% of the total volume of the electroless nickel plating waste liquid is introduced into the complex breaker, and stirred for 15-25 min; when the pH of the electroless nickel plating waste liquid begins to rise, UV light is introduced and stirring is continued until the pH no longer changes;

[0010] The method of introducing UV light is: taking one minute as the basis, the change rate of pH < 0.05, the intensity of UV light is 20-25 μmol·m -2 ·s -1 , and the irradiation intensity is increased by 3-5 μmol·m -2 ·s -1 per minute until 0.05 ≤ the change rate of pH, and the intensity of UV light is reduced to 5-10 μmol·m -2 ·s -1 ;

[0011] The electroless nickel plating wastewater is subjected to nanofiltration separation at 20-30℃ and 5-15 MPa using a roll-type nanofiltration membrane to obtain a nickel-containing wastewater, a wastewater containing hypophosphorous acid and ammonia;

[0012] S2, bipolar membrane electrodialysis:

[0013] The arrangement of the bipolar membrane electrodialysis system is set as: the anode, the first bipolar membrane, the anion membrane, the cation membrane, the second bipolar membrane, and the cathode are arranged in sequence, the area between the first bipolar membrane and the anion membrane is the acid chamber, the area between the cation membrane and the second bipolar membrane is the alkali chamber, and the area between the anion membrane and the cation membrane is the desalination chamber;

[0014] The wastewater containing hypophosphorous acid and ammonia is introduced into the desalination chamber, deionized water is added to the acid chamber and the alkali chamber, and the volume ratio of deionized water in the acid chamber to that in the alkali chamber is 1:2-3, wherein the voltage of the bipolar membrane electrodialysis is 10-30 V, and the current density is 15-25 A / m 2 , the hypophosphite ion enters the acid chamber, the ammonium ion enters the alkali chamber, further hypophosphorous acid solution and ammonia gas are obtained, until no ammonia gas is generated, the bipolar membrane electrodialysis is completed, and the separation of hypophosphorous acid and ammonia is realized.

[0015] Further, the roll-type nanofiltration membrane uses one of NF90, DK8040F-30P, and TM620N-400.

[0016] Note: NF90 nanofiltration membrane is used for Ni 2+The wastewater has good treatment effect, and the removal rate is more than 98%; the DK8040F-30P nanofiltration membrane is excellent in mechanical strength and anti-pollution performance, has low requirement on the quality of the inlet water, small operation pressure, low energy consumption, high flux, and can effectively remove microorganisms, colloids, suspended solids and other impurities in water; the TM620N-400 has the characteristics of acid resistance, corrosion resistance and high chemical stability, can effectively purify high-concentration heavy metals such as nickel in wastewater, and realize more than 90% of wastewater recovery and purification.

[0017] Further, the anion membrane adopts FAA-PK-130 or AMI-7001S, and the cation membrane adopts FKB-PK-130 or FKL-PK-130.

[0018] Description: The above membrane types can selectively transmit anions or cations, and can effectively separate specific anion species or cation species from a solution.

[0019] Further, the first bipolar membrane and the second bipolar membrane both adopt one of BPM-6012-50, BMP-200 and JED-6012-40.

[0020] Description: The above bipolar membranes can provide efficient ion exchange and separation in the process of electrodialysis.

[0021] Further, the total time T of passing the wastewater containing hypophosphorous acid and ammonia into the dilution chamber is divided into multiple equal time periods t1, t2, t3, … t n , n = 6-15; the value of T is 30-45 min, and the values of t1…t n are all 3-5 min, and the production rate V t of ammonia gas in the alkali chamber in each time period is detected; wherein the passing rate of the wastewater containing hypophosphorous acid and ammonia in the first time period t1 is 4-6 L / min, the temperature in the alkali chamber is 20-25℃, and the pressure in the alkali chamber is 5-10 MPa.

[0022] When V t-1 -V t ≤0, compared with the previous time period, the temperature in the alkali chamber is increased by 1.4-1.6 times, the pressure in the alkali chamber is reduced by 50-60%, and the passing rate of the wastewater containing hypophosphorous acid and ammonia is increased by 15-20%;

[0023] When 0<V t-1 -V t , compared with the previous time period, the temperature in the alkali chamber is kept unchanged, the pressure in the alkali chamber is reduced by 10-20%, and the passing rate of the wastewater containing hypophosphorous acid and ammonia is reduced by 5-10%.

[0024] Note: After nanofiltration, there may still be a small amount of nickel left in the wastewater. Therefore, the ammonia generation rate in each time period is tested. When the generation rate changes, it may be affected by nickel. When the rate decreases, increasing the solution's fluidity by increasing the temperature can reduce the viscosity, thereby accelerating ion migration and improving separation efficiency. Reducing the pressure can lower the boiling point of water, which is conducive to the volatilization and collection of ammonia, further improving the separation rate of ammonia. Increasing the wastewater flow rate can process more wastewater in a unit of time, increase the supply of ammonium ions, and promote the generation of ammonia.

[0025] When the rate increases, continuing to reduce the pressure can maintain the ammonia generation rate, keeping it efficient. However, too high an ammonia generation rate can increase the burden on the ion exchange membrane, reducing the performance of the membrane. Therefore, by reducing the flow rate, the workload of the membrane can be reduced, the risk of membrane contamination can be reduced, and the ammonia concentration in the system can be reduced, reducing the impact of gas-liquid equilibrium, which helps ammonia to more easily escape from the wastewater and be captured by the collection system.

[0026] Further, when V t-1 -V t ≤-20%~-30%V t , first perform plasma activation treatment on the deionized water in the alkali chamber to obtain plasma-activated water, and set the turbulence intensity of the plasma-activated water to 5-6%; wherein the plasma activation treatment time is 1-2 min, and the power is 600-700 W.

[0027] When-20%~-30%V t <V t-1 -V t ≤0, first perform plasma activation treatment on the deionized water in the alkali chamber to obtain plasma-activated water, and set the turbulence intensity of the plasma-activated water to 2-3%; wherein the plasma activation treatment time is 0.5-1 min, and the power is 450-550 W.

[0028] Note: Plasma activation can improve water activity and promote hydrolysis reactions, thereby facilitating ammonia generation. When the ammonia generation rate decreases, activation can stimulate ammonia release and improve ammonia recovery efficiency. However, when the ammonia generation rate no longer decreases significantly, reducing plasma activation and turbulence intensity can reduce power consumption, helping to lower overall operating costs. Adjusting the degree of plasma activation and turbulence intensity according to the real-time changes in ammonia generation rate can more finely control the electrodialysis process, ensuring optimal reaction conditions and avoiding excessive resource consumption.

[0029] Further, the method of plasma activation treatment is to spray the plasma prepared by a low-temperature plasma generator into the deionized water in the alkali chamber.

[0030] Explanation: The plasma generated by the low-temperature plasma generator is sprayed into water to produce so-called low-temperature plasma active water, which contains active oxidants and is helpful for the generation of ammonia.

[0031] Compared with the existing method for separating nickel, hypophosphorous acid and ammonia in wastewater, the present application has the following advantages:

[0032] (1) The separation method of the present application can realize the effective release of nickel at a lower pH value through acidification treatment, and then the addition of a complex breaker can effectively destroy the structure of the complex nickel in the wastewater to release free nickel ions, which is helpful for the subsequent nickel recovery process. The change of pH is adjusted by UV irradiation. Initially, a higher intensity of UV irradiation (20-25 μmol·m-2·s-1) is used to accelerate the complex breaking reaction, so that the pH change rate increases to 0.05 or more, which indicates that the stability of the complex is quickly destroyed and the nickel ions are released, thereby improving the complex breaking efficiency. When the pH change rate reaches or exceeds 0.05, the intensity of UV irradiation is reduced, which helps to balance the reaction rate and energy consumption, avoids the increase of energy consumption and possible side reactions caused by excessive light irradiation, and stops the UV irradiation when the pH no longer changes, which indicates that the reaction has reached equilibrium. The conditions at this time are conducive to the complete release and selective removal of nickel ions. Then, nanofiltration can effectively intercept multivalent ions such as nickel ions, while bipolar membrane electrodialysis can utilize its unique ion exchange function to convert hypophosphite and ammonia ions into corresponding acids and bases, respectively, to achieve their effective separation. Bipolar membrane electrodialysis is an electrically driven process that does not require the addition of chemical reagents. Compared with the traditional chemical precipitation method, it can save energy and chemical reagent usage, reduce processing cost, and through bipolar membrane electrodialysis, hypophosphite and ammonia ions can be converted into phosphoric acid and ammonia water, thereby improving the purity of these products and facilitating their subsequent recovery and utilization.

[0033] (2) The separation method of the present application reduces the influence of a small amount of nickel that may still remain in the wastewater after nanofiltration by dividing the bipolar membrane electrodialysis process into multiple time periods, i.e., by testing the ammonia generation rate in each time period, when the generation rate changes, it is possible that there is the influence of nickel; when the rate decreases, the solution mobility is increased by increasing the temperature to reduce the viscosity, thereby accelerating the ion migration and improving the separation efficiency; by reducing the pressure, the boiling point of water can be reduced, which is conducive to the volatilization and collection of ammonia, further improving the separation rate of ammonia; increasing the flow rate of the wastewater can process more wastewater in unit time, which can increase the supply of ammonium ions and promote the generation of ammonia; when the rate increases, the ammonia generation rate can be maintained by continuing to reduce the pressure, so that it remains efficient; however, too high an ammonia generation rate can increase the burden on the ion exchange membrane and reduce the performance of the membrane, therefore, by reducing the flow rate, the workload of the membrane can be reduced, the risk of membrane pollution can be reduced, and the ammonia concentration in the system can be reduced, which reduces the influence of gas-liquid equilibrium, and helps the ammonia gas to escape from the wastewater more easily and be captured by the collection system. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flow diagram of the separation method of the present application;

[0035] Figure 2 is a comparison chart of the results of the separation method exploration 2 of the present application;

[0036] Figure 3 is a comparison chart of the results of the separation method exploration 3 of the present application;

[0037] Figure 4 is a comparison chart of the results of the separation method exploration 4 of the present application. DETAILED DESCRIPTION

[0038] To further illustrate the manner in which the application is made and to implement the effects achieved by the application, the technical solutions of the application will be described below in conjunction with experiments.

[0039] Example 1: A method for efficiently separating nickel, hypophosphorous acid and ammonia from electroless nickel plating wastewater, as shown in Figure 1 , comprising the following steps:

[0040] S1, nanofiltration:

[0041] First, adjust the pH of the electroless nickel plating wastewater to 5.5, then introduce a chelate breaker such as sodium ferrate into 0.9% of the total volume of the electroless nickel plating wastewater, and stir for 20 min; when the pH of the electroless nickel plating wastewater begins to rise, introduce UV light and continue to stir until the pH no longer changes;

[0042] The method of introducing UV light is: taking one minute as the basis, the pH change rate < 0.05, the intensity of UV light is 23 pmol·m-2 ·s -1 , and irradiated continuously with an increasing light intensity of 4 pmol m-2s-1 per minute until the rate of change of pH was 0.05, the intensity of UV irradiation was reduced to 7 pmol m-2s-1. -2 ·s -1 -2 ·s -1 ;

[0043] The chemical nickel plating wastewater is subjected to nanofiltration separation at 25 DEG C and 10 MPa by using a nanofiltration membrane, wherein the nanofiltration membrane is NF90, and the nanofiltration separation obtains the wastewater containing nickel, the wastewater containing hypophosphorous acid and ammonia;

[0044] S2, bipolar membrane electrodialysis:

[0045] The arrangement mode of the bipolar membrane electrodialysis system is set as follows: the anode, the first bipolar membrane, the anion membrane, the cation membrane, the second bipolar membrane and the cathode are arranged in sequence, the region between the first bipolar membrane and the anion membrane is an acid chamber, the region between the cation membrane and the second bipolar membrane is an alkali chamber, and the region between the anion membrane and the cation membrane is a desalination chamber; the anion membrane is FAA-PK-130, the cation membrane is FKB-PK-130, and the first bipolar membrane and the second bipolar membrane are both BPM-6012-50;

[0046] The wastewater containing hypophosphorous acid and ammonia is introduced into the desalination chamber, deionized water is added into the acid chamber and the alkali chamber, and the volume ratio of the deionized water in the acid chamber to the deionized water in the alkali chamber is 1:2.5, wherein the voltage of the bipolar membrane electrodialysis is 20 V, and the current density is 20 A / m 2 , the hypophosphite ions enter the acid chamber, the ammonium ions enter the alkali chamber, further hypophosphorous acid solution and ammonia gas are obtained, until no ammonia gas is generated, the bipolar membrane electrodialysis is completed, and the separation of hypophosphorous acid and ammonia is realized;

[0047] The ammonia gas is recovered by using a hydrochloric acid solution with a concentration of 300 g / L to absorb the ammonia gas, so as to obtain ammonium chloride, and the recovery is completed.

[0048] Example 2: The difference between the present example and Example 1 is that the pH of the chemical nickel plating wastewater is first adjusted to 6, and then 0.8% of the total volume of the chemical nickel plating wastewater is added into the complex breaker, and stirred for 15 min.

[0049] Example 3: The difference between the present example and Example 1 is that the pH of the chemical nickel plating wastewater is first adjusted to 5, and then 1% of the total volume of the chemical nickel plating wastewater is added into the complex breaker, and stirred for 25 min.

[0050] ​Example 4: The difference between this example and Example 1 is that the rate of change of pH is < 0.05 on a one minute basis, the intensity of UV irradiation is 20 pmol m -2 ·s -1 , and the irradiation is continued with an increase of 3 pmol m -2 ·s -1 per minute until 0.05 < rate of change of pH, and the intensity of UV irradiation is reduced to 10 pmol m -2 ·s -1 .

[0051] Example 5: The difference between this example and Example 1 is that the rate of change of pH is < 0.05 on a one minute basis, the intensity of UV irradiation is 25 pmol m -2 ·s -1 , and the irradiation is continued with an increase of 5 pmol m -2 ·s -1 per minute until 0.05 < rate of change of pH, and the intensity of UV irradiation is reduced to 5 pmol m -2 ·s -1 .

[0052] Example 6: The difference between this example and Example 1 is that the electroless nickel plating wastewater is subjected to nanofiltration separation at 20℃ and 5MPa using a spiral nanofiltration membrane, and the spiral nanofiltration membrane used is DK8040F-30P.

[0053] Example 7: The difference between this example and Example 1 is that the electroless nickel plating wastewater is subjected to nanofiltration separation at 30℃ and 15MPa using a spiral nanofiltration membrane, and the spiral nanofiltration membrane used is TM620N-400.

[0054] Example 8: The difference between this example and Example 1 is that the volume ratio of deionized water in the acid chamber to the base chamber is 1:2, the anion membrane used is AMI-7001S, and the cation membrane used is FKB-PK-130.

[0055] Example 9: The difference between this example and Example 1 is that the volume ratio of deionized water in the acid chamber to the base chamber is 1:3, the anion membrane used is FAA-PK-130, and the cation membrane used is FKL-PK-130.

[0056] Example 10: The difference between this example and Example 1 is that the voltage for bipolar membrane electrodialysis is 10V, the current density is 15A / m 2 , and both the first bipolar membrane and the second bipolar membrane used are BMP-200.

[0057] Example 11: The difference between this example and Example 1 is that the voltage of the bipolar membrane electrodialysis is 30 V, and the current density is 25 A / m 2 , and the first bipolar membrane and the second bipolar membrane are both JED-6012-40.

[0058] Example 12: The difference between this example and Example 1 is that the total time T of passing the hypophosphorous acid and ammonia-containing wastewater into the desalination chamber is divided into multiple equal time periods t1, t2, t3,... t n , n = 9; the value of T is 36 min, and the values of t1... t n are all 4 min, and the ammonia gas production rate V t in the alkali chamber in each time period is detected; wherein the passing rate of the hypophosphorous acid and ammonia-containing wastewater in the first time period t1 is 5 L / min, the temperature in the alkali chamber is 23℃, and the pressure in the alkali chamber is 7.5 MPa.

[0059] When V t-1 -V t ≤ 0, compared with the previous time period, the temperature in the alkali chamber is increased by 1.5 times, the pressure in the alkali chamber is reduced by 55%, and the passing rate of the hypophosphorous acid and ammonia-containing wastewater is increased by 17.5%.

[0060] When 0 < V t-1 -V t , compared with the previous time period, the temperature in the alkali chamber is kept unchanged, the pressure in the alkali chamber is reduced by 15%, and the passing rate of the hypophosphorous acid and ammonia-containing wastewater is reduced by 7.5%.

[0061] Example 13: The difference between this example and Example 12 is that the value of T is 30 min, and the values of t1... t n are all 3 min.

[0062] Example 14: The difference between this example and Example 12 is that the value of T is 45 min, and the values of t1... t n are all 5 min.

[0063] Example 15: The difference between this example and Example 12 is that the passing rate of the hypophosphorous acid and ammonia-containing wastewater in the first time period t1 is 4 L / min, the temperature in the alkali chamber is 20℃, and the pressure in the alkali chamber is 10 MPa.

[0064] Example 16: The difference between this example and Example 12 is that the passing rate of the hypophosphorous acid and ammonia-containing wastewater in the first time period t1 is 6 L / min, the temperature in the alkali chamber is 25℃, and the pressure in the alkali chamber is 5 MPa.

[0065] Example 17: The difference between this example and Example 12 is that when V t-1 -V t ≤ 0, the temperature in the alkali chamber is increased by 1.4 times, the pressure in the alkali chamber is reduced by 50%, and the flow rate of the wastewater containing hypophosphorous acid and ammonia is increased by 15% compared with the previous time period.

[0066] Example 18: The difference between this example and Example 12 is that when V t-1 -V t ≤ 0, the temperature in the alkali chamber is increased by 1.6 times, the pressure in the alkali chamber is reduced by 60%, and the flow rate of the wastewater containing hypophosphorous acid and ammonia is increased by 20% compared with the previous time period.

[0067] Example 19: The difference between this example and Example 12 is that when 0 < V t-1 -V t , the temperature in the alkali chamber is kept unchanged, the pressure in the alkali chamber is reduced by 10%, and the flow rate of the wastewater containing hypophosphorous acid and ammonia is reduced by 5% compared with the previous time period.

[0068] Example 20: The difference between this example and Example 12 is that when 0 < V t-1 -V t , the temperature in the alkali chamber is kept unchanged, the pressure in the alkali chamber is reduced by 20%, and the flow rate of the wastewater containing hypophosphorous acid and ammonia is reduced by 10% compared with the previous time period.

[0069] Example 21: The difference between this example and Example 12 is that when V t-1 -V t ≤ -20% ~ -30% V t , the deionized water in the alkali chamber is subjected to plasma activation treatment to obtain plasma-activated water, and the turbulent intensity of the plasma-activated water is set to 5.5%; wherein the plasma activation treatment time is 1.5 min, and the power is 650 W;

[0070] When -20% ~ -30% V t < V t-1 -V t ≤ 0, the deionized water in the alkali chamber is subjected to plasma activation treatment to obtain plasma-activated water, and the turbulent intensity of the plasma-activated water is set to 2.5%; wherein the plasma activation treatment time is 0.8 min, and the power is 500 W;

[0071] The method of the plasma activation treatment is that the plasma prepared by the low-temperature plasma generator is sprayed into the deionized water in the alkali chamber.

[0072] Example 22: The difference between this example and Example 21 is that when Vt-1 -V t ≤-20%~-30%V t When V≤-20%~-30%, the turbulent intensity of the plasma-activated water is set to 5%; wherein the plasma-activated treatment time is 1 min and the power is 600 W.

[0073] Example 23: The difference between this example and Example 21 is that when V t-1 -V t ≤-20%~-30%V t When V≤-20%~-30%, the turbulent intensity of the plasma-activated water is set to 6%; wherein the plasma-activated treatment time is 2 min and the power is 700 W.

[0074] Example 24: The difference between this example and Example 21 is that when V t <V t-1 -V t ≤0, the turbulent intensity of the plasma-activated water is set to 2%; wherein the plasma-activated treatment time is 0.5 min and the power is 450 W.

[0075] Example 25: The difference between this example and Example 21 is that when V t <V t-1 -V t ≤0, the turbulent intensity of the plasma-activated water is set to 3%; wherein the plasma-activated treatment time is 1 min and the power is 550 W.

[0076] Experimental Example: The description of this experimental example is based on the description in Example 1, and is intended to illustrate the actual application effect of the present application.

[0077] In order to illustrate the advantages of the separation method of the present application, the concentrations of nickel, hypophosphorous acid and ammonia in the wastewater before separation are tested, and compared with the concentrations of nickel, hypophosphorous acid and ammonia in the wastewater after nanofiltration and bipolar membrane electrodialysis, so as to obtain the separation rates of nickel, hypophosphorous acid and ammonia, which are used as the performance data of the separation method of the present application.

[0078] 1. To explore the influence of the parameters of the breakage treatment and nanofiltration on the separation rate of nickel.

[0079] Table 1: Separation rate of nickel in Examples 1-7

[0080] Group Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 % Isolation 99.98 99.86 99.92 99.78 99.89 99.91 99.93

[0081] From the data in Table 1, it can be seen that too small or too large parameters of the acidification breakage treatment, too small or too large change amount of UV light intensity, and too small or too large nanofiltration parameters will all reduce the separation rate of nickel. It can be seen that the separation rate of nickel after the breakage treatment and nanofiltration is higher, and the separation rate is stable at more than 99.75%.

[0082] 2. Explore the influence of bipolar membrane electrodialysis parameters on the separation rate of hypophosphorous acid and ammonia.

[0083] By Figure 2 The results show that, compared with Examples 1-11, the volume of deionized water in the acid chamber is too small or too large, the voltage and current of bipolar membrane electrodialysis are too small or too large, which will reduce the separation rate of hypophosphorous acid and ammonia. In general, the parameters of Example 1 are relatively more optimal.

[0084] 3. Explore the influence of treatment parameters of the alkali chamber on the separation rate of ammonia in bipolar membrane electrodialysis.

[0085] The difference between Comparative Example 1 and Example 12 is that the flow rate remains unchanged at each time period;

[0086] The difference between Comparative Example 2 and Example 12 is that when 0 < V t-1 -V t The temperature and pressure in the alkali chamber remain unchanged compared with the previous time period;

[0087] By Figure 3 The results show that, compared with Examples 1, 12-20 and Comparative Examples 1-2, adjusting the temperature and pressure parameters of the alkali chamber according to the change in ammonia gas production rate significantly improves the separation rate of ammonia. Compared with Examples 12-20 and Comparative Examples 1-2, Comparative Example 1 lacks the flexibility of flow rate, and Comparative Example 2 lacks the flexibility of parameters after the ammonia gas production rate increases. Therefore, the regular change in Example 8 has a beneficial effect on improving the separation rate of ammonia.

[0088] Comparative Examples 12-20, the time period is too small or too large, the parameters of the first time period are too small or too large, the adjustment range of the parameters after the ammonia gas production rate decreases is too small or too large, and the adjustment range of the parameters after the ammonia gas production rate increases is too small or too large, which will reduce the improvement effect of the separation rate of ammonia. Therefore, in general, the parameters of Example 8 are relatively more optimal.

[0089] 4. Explore the influence of treatment parameters of the alkali chamber on the separation rate of ammonia when the ammonia gas production rate decreases in bipolar membrane electrodialysis.

[0090] By Figure 4 The results show that, compared with Examples 12, 21-25, ion plasma activation of deionized water in the alkali chamber further improves the separation rate of ammonia when the ammonia gas production rate decreases.

[0091] Comparative Examples 21 to 25, when the ammonia generation rate decreases more, the plasma activation parameters are too small or too large, and when the ammonia generation rate decreases less, the plasma activation parameters are too small or too large, all of which reduce the separation rate of ammonia, and therefore, in comparison, the parameters of Example 21 are relatively more optimal.

Claims

1. A method for efficiently separating nickel, hypophosphorous acid and ammonia from a waste solution of electroless nickel plating, characterized by, The method comprises the following steps: S1, nanofiltration: First, adjust the pH of the electroless nickel plating waste liquid to 5-6, then introduce 0.8-1% of the total volume of the electroless nickel plating waste liquid into the complex breaker, and stir for 15-25 min; when the pH of the electroless nickel plating waste liquid begins to rise, introduce UV light and continue to stir until the pH no longer changes; The method for introducing UV light is: taking one minute as a reference, the change rate of pH is less than 0.05, the intensity of UV light is 20-25 μmol·m -2 ·s -1 , and the light intensity is increased by 3-5 μmol·m -2 ·s -1 per minute until 0.05≤the change rate of pH, and the intensity of UV light is reduced to 5-10 μmol·m -2 ·s -1 . Then, use a roll-type nanofiltration membrane to perform nanofiltration separation on the electroless nickel plating wastewater at 20-30℃ and 5-15 MPa, to obtain a nickel-containing wastewater, a hypophosphorous acid and ammonia-containing wastewater; S2, bipolar membrane electrodialysis: The arrangement mode of the bipolar membrane electrodialysis system is: the anode, the first bipolar membrane, the anion membrane, the cation membrane, the second bipolar membrane, and the cathode are arranged in sequence, the region between the first bipolar membrane and the anion membrane is an acid chamber, the region between the cation membrane and the second bipolar membrane is an alkali chamber, and the region between the anion membrane and the cation membrane is a desalination chamber; The waste water containing hypophosphorous acid and ammonia is introduced into the desalination chamber, deionized water is added into the acid chamber and the base chamber, and the volume ratio of the deionized water in the acid chamber to the deionized water in the base chamber is 1:2-3, wherein the voltage of the bipolar membrane electrodialysis is 10-30 V, and the current density is 15-25 A / m 2 The hypophosphite ions enter the acid chamber, the ammonium ions enter the base chamber, hypophosphorous acid solution and ammonia gas are further obtained, until no ammonia gas is generated, the bipolar membrane electrodialysis is completed, and the separation of hypophosphorous acid and ammonia is realized.

2. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the electroless nickel plating waste solution according to claim 1, characterized in that, The roll-type nanofiltration membrane uses one of NF90, DK8040F-30P, and TM620N-400.

3. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the electroless nickel plating waste solution according to claim 1, characterized in that, The anion membrane uses FAA-PK-130 or AMI-7001S, and the cation membrane uses FKB-PK-130 or FKL-PK130.

4. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the electroless nickel plating waste solution according to claim 1, characterized in that, The first bipolar membrane and the second bipolar membrane both use one of BPM-6012-50, BMP-200, and JED-6012-40.

5. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the waste solution of electroless nickel plating according to claim 1, characterized in that, The total time T of passing the hypophosphorous acid and ammonia containing wastewater into the desalination chamber is divided into multiple equal length time periods t1, t2, t3,... t n , n = 6-15; the T value is 30-45 min, the t1....t n values are all 3-5 min, and the ammonia gas production rate V n in the alkali chamber in each time period t1....t t is detected. In the first time period t1, the hypophosphorous acid and ammonia-containing wastewater is introduced at a rate of 4-6 L / min, the temperature in the alkali chamber is 20-25℃, and the pressure in the alkali chamber is 5-10 MPa. When V t-1 -V t ≤0, the temperature in the alkali chamber is increased by 1.4-1.6 times, the pressure in the alkali chamber is reduced by 50-60%, and the feeding rate of the wastewater containing hypophosphorous acid and ammonia is increased by 15-20% compared with the previous time period. When 0 < V t-1 - V t The temperature in the alkali chamber is kept constant, the pressure in the alkali chamber is reduced by 10-20%, and the flow rate of the wastewater containing hypophosphorous acid and ammonia is reduced by 5-10% compared with the previous time period.

6. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the electroless nickel plating waste solution according to claim 5, characterized in that, When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V t-1 -V t ≤-20%~-30%V t When V <000001 When -20% to -30% V t <V t-1 -V t ≤0, first plasma-activated treatment is performed on the deionized water in the alkali chamber to obtain plasma-activated water, and the turbulent intensity of the plasma-activated water is set to 2-3%; wherein the plasma-activated treatment time is 0.5-1 min, and the power is 450-550 W.

7. The method for efficiently separating nickel, hypophosphorous acid and ammonia from the electroless nickel plating waste solution according to claim 6, characterized in that, The method of the plasma activation treatment is: spraying the plasma prepared by a low-temperature plasma generator into the deionized water in the alkali chamber.

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