A regeneration method for a sodium carboxylate gel-type ion exchange resin

Abstract

This application relates to the technical field of ion exchange resin regeneration, and specifically discloses a regeneration method for carboxylate gel-type ion exchange resin. The regeneration method comprises the following steps: continuously passing a hydrochloric acid solution into the adsorption-saturated carboxylate gel-type ion exchange resin, then continuously passing an organic acid treatment solution into the carboxylate gel-type ion exchange resin, and finally continuously passing an alkali solution into the carboxylate gel-type ion exchange resin and washing with water until the effluent is neutral; wherein, the organic acid treatment solution contains 0.1-0.5 wt% surfactant, the organic acid in the organic acid treatment solution includes strong organic acids, and the strong organic acids are selected from at least one of benzenesulfonic acid, acrylic acid and citric acid. The resin obtained by the regeneration method of this application has the advantages of high regeneration rate and many repeated use times.

Description

Technical Field

[0001] This application relates to the technical field of ion exchange resin regeneration. More specifically, it relates to a regeneration method for carboxylate gel-type ion exchange resin. Background Art

[0002] The difference between heavy metal pollutants and conventional organic pollutants is that heavy metal pollutants cannot be biodegraded during the biosphere material cycle. Heavy metal pollutants can enter the food chain through various ways, and are easily accumulated in organisms, and induce various toxic biochemical reactions, thus damaging human health. Relevant environmental protection regulations have imposed strict restrictions on the concentration of heavy metal pollutants in industrial wastewater discharges, and have also imposed strict restrictions on the concentration of heavy metal ions in domestic drinking water, and have indicated the need for source treatment of industrial wastewater heavy metal pollutants to significantly reduce the concentration of heavy metal ions in the wastewater discharged from factories.

[0003] Heavy metal pollutants usually come from industrial production fields such as metal mineral processing, metallurgy, glass production, mining, metal electroplating, battery manufacturing, etc. Production enterprises need to perform pretreatment of production wastewater and adopt efficient heavy metal removal measures or technologies to reduce the concentration of heavy metal pollutants in the discharged wastewater. Among various treatment methods, compared with chemical addition of alkali solution precipitation and membrane separation technology, the ion exchange resin adsorption technology has the advantages of excellent heavy metal removal efficiency and no secondary pollution, and the ion exchange resin can be reused through regeneration with low economic investment. Among them, the carboxylate gel-type ion exchange resin can absorb water and swell in water, and the water absorption ratio is much higher than that of the carboxylate styrene-based ion exchange resin. The high water absorption and swelling ratio property can greatly improve the interception efficiency of the resin for heavy metal pollutants. At the same time, the carboxylate gel-type ion exchange resin has high selectivity and can specifically adsorb heavy metal ions in sewage, and conventional sodium and potassium ions will not be adsorbed. Therefore, the carboxylate gel adsorbent is widely used in removing heavy metal pollutants in sewage.

[0004] The existing regeneration method for carboxylate gel-type ion exchange resin is to use a 10% mass fraction sodium chloride solution for regeneration. However, this method has problems such as low regeneration efficiency, high consumption of the regeneration liquid volume, difficulty in recovering precious metals from the regeneration liquid, and too high salt concentration in the waste regeneration liquid, which is not easy to be harmlessly disposed of.

[0005] In the prior art, the ion exchange resin is regenerated by eluting with sulfuric acid and then desorbing with an alkali solution. On the one hand, this method can ensure the regeneration rate of the ion exchange resin and its secondary utilization, reduce the consumption of the regeneration liquid, and on the other hand, it can also realize the resource recovery of useful metals. However, this method still has problems such as low regeneration rate of the ion exchange resin (only about 85% level) and low number of times of repeated utilization of the ion exchange resin.

[0006] Therefore, it is necessary to provide a regeneration method for carboxylate gel-type ion exchange resin to improve the regeneration rate and the number of times of repeated use of the ion exchange resin. Summary of the Invention

[0007] In order to improve the regeneration rate and the number of times of repeated use of the ion exchange resin, the present application provides a regeneration method for carboxylate gel-type ion exchange resin.

[0008] The regeneration method for carboxylate gel-type ion exchange resin provided by the present application adopts the following technical solutions:

[0009] A regeneration method for carboxylate gel-type ion exchange resin includes the following steps:

[0010] Continuously introduce hydrochloric acid solution into the adsorption-saturated carboxylate gel-type ion exchange resin, then continuously introduce the organic acid treatment solution into the carboxylate gel-type ion exchange resin, and finally continuously introduce the alkali solution into the carboxylate gel-type ion exchange resin and wash with water until the effluent is neutral.

[0011] Among them, the organic acid treatment solution contains a surfactant, the organic acid in the organic acid treatment solution includes a strong organic acid, and the strong organic acid is selected from at least one of benzenesulfonic acid and acrylic acid.

[0012] If only hydrochloric acid solution and then alkali solution are used for treatment, in this process, the hydrochloric acid solution and the carboxylate gel-type ion exchange resin undergo cation exchange to displace the heavy metals adsorbed on the carboxylate gel-type ion exchange resin and obtain a hydrogen-type ion exchange resin; then the ion exchange resin is washed with alkali solution to convert the hydrogen-type ion exchange resin into a carboxylate gel-type ion exchange resin; finally, it is washed with deionized water to remove the residual alkali solution in the ion exchange column and at the same time make the carboxylate gel-type ion exchange resin fully absorb water and swell, which can improve the absorption efficiency of the carboxylate gel-type ion exchange resin for heavy metal pollutants.

[0013] However, when the sewage containing heavy metal pollutants also contains COD, when treating this type of sewage with sodium carboxylate gel-type ion exchange resin, part of the COD is also adsorbed on the sodium carboxylate gel-type ion exchange resin together with the heavy metals; there is a certain intermolecular force between the hydrophobic groups in COD and the hydrophobic groups in the sodium carboxylate gel-type ion exchange resin. After treatment with hydrochloric acid solution, part of the COD still adheres to the sodium carboxylate gel-type ion exchange resin and is difficult to separate from the sodium carboxylate gel-type ion exchange resin, resulting in a low regeneration rate of the sodium carboxylate gel-type ion exchange resin. The regeneration rate of the regenerated sodium carboxylate gel-type ion exchange resin is difficult to reach 90%. Therefore, by adopting the above technical solution, in the present application, after treating the sodium carboxylate gel-type ion exchange resin with hydrochloric acid solution, the sodium carboxylate gel-type ion exchange resin is further treated with an organic acid treatment solution. Among them, the surfactant in the organic acid treatment solution improves the performance of COD, making COD easily dispersed in the organic acid treatment solution; at the same time, the strong organic acids in it all contain non-polar groups, further improving the polarity of the organic acid treatment solution, making COD more inclined to be dispersed in the organic acid treatment solution, thereby realizing the separation of COD and the sodium carboxylate gel-type ion exchange resin, and further improving the regeneration rate of the sodium carboxylate gel-type ion exchange resin.

[0014] Optionally, the content of the strong organic acid in the organic acid treatment solution is 0.01 - 0.05 mol / L.

[0015] Through the above technical solution, the content of the strong organic acid is within an appropriate range. If the content of the organic acid is too small, it is still difficult to achieve the separation of COD and the sodium carboxylate gel-type ion exchange resin; if the content of the organic acid is too large, the residue of the organic acid will also affect the regeneration rate of the sodium carboxylate gel-type ion exchange resin.

[0016] Optionally, the treatment time of the organic acid treatment solution is 20 - 30 min.

[0017] Optionally, the addition amount of the surfactant in the organic acid treatment solution is 0.1 - 0.5 wt%.

[0018] Optionally, the surfactant is selected from at least one of sodium dodecylbenzenesulfonate, α-olefin sulfonate, and vinyl sulfonate.

[0019] Optionally, the organic acid treatment solution is heated and then passed into the sodium carboxylate gel-type ion exchange resin, and the heating temperature is 45 - 60 °C.

[0020] In the present application, the heating temperature can be 45 °C, 47 °C, 51 °C, 54 °C, 57 °C, or 60 °C.

[0021] The applicant found that through the above technical solution, the regeneration rate of the sodium carboxylate gel-type ion exchange resin can be further improved after heating.

[0022] Optionally, the organic acid further includes a weak organic acid; the weak organic acid is selected from at least one of phenol and acetic acid.

[0023] Through the above technical solution, the organic group provided by the weak organic acid further improves the affinity between the organic acid treatment liquid and COD, thereby further improving the separation effect of COD and the carboxylate gel-type ion exchange resin, and making the regeneration rate of the carboxylate gel-type ion exchange resin higher.

[0024] Optionally, the molar ratio of the weak organic acid to the strong organic acid is (0.2-0.5):1.

[0025] In the present application, the molar ratio of the weak organic acid to the strong organic acid can be 0.2:1, 0.3:1, 0.4:1 or 0.5:1.

[0026] Optionally, the time for continuously introducing the hydrochloric acid solution into the carboxylate gel-type ion exchange resin is 30-60 min, and the concentration of hydrochloric acid in the hydrochloric acid solution is 0.07-0.13 mol / L.

[0027] Through the above technical solution, selecting an appropriate hydrochloric acid concentration and treatment time can ensure a high regeneration rate of the carboxylate gel-type ion exchange resin.

[0028] Optionally, the time for continuously introducing the alkali solution into the carboxylate gel-type ion exchange resin is 45-80 min; the concentration of the alkali in the alkali solution is 0.071-0.153 mol / L.

[0029] By adopting the above technical solution, selecting an appropriate alkali concentration and treatment time can ensure a high regeneration rate of the carboxylate gel-type ion exchange resin.

[0030] In summary, the present application has the following beneficial effects:

[0031] 1. It is found in the present application that when treating electroplating wastewater with a carboxylate gel-type ion exchange resin, the COD therein will adhere to the resin, and it is difficult to effectively remove it through traditional regeneration methods, resulting in a low regeneration conversion rate of the carboxylate gel-type ion exchange resin. By adding a treatment step of an organic acid treatment liquid between the hydrochloric acid treatment and the alkali solution treatment, the organic acid and surfactant in the organic acid treatment liquid cooperate to improve the interaction force between the COD and the resin, making the affinity between the COD and the organic acid treatment liquid higher, thereby separating the COD from the carboxylate gel-type ion exchange resin, and then significantly improving the regeneration rate of the carboxylate gel-type ion exchange resin.

[0032] 2. The present application further improves the affinity of the organic acid treatment liquid by adding a strong organic acid and a weak organic acid together, and further improves the regeneration rate of the carboxylate gel-type ion exchange resin.

[0033] 3. The method of the present application further improves its treatment effect by heating the organic acid treatment liquid, thereby improving the regeneration rate of the sodium carboxylate gel-type ion exchange resin. Detailed implementation manners

[0034] The present application will be further described in detail below with reference to embodiments. The raw materials involved in the present application are all obtained from ordinary commercial sources unless otherwise specified.

[0035] Embodiments

[0036] An ion exchange column filled with a new sodium carboxylate gel-type ion exchange resin is used to treat the electroplating solution wastewater containing 40 mg / L COD in the nickel plating process, and then the sodium carboxylate gel-type ion exchange resin is regenerated.

[0037] Embodiment 1

[0038] A regeneration method for a sodium carboxylate gel-type ion exchange resin, the steps of which are as follows:

[0039] S1. After the ion exchange column filled with the sodium carboxylate gel-type ion exchange resin adsorbs heavy metals to saturation, regeneration operation is carried out. Close the sewage inlet valve of the ion exchange column, open the injection pump of 0.07 mol / L hydrochloric acid solution to inject hydrochloric acid solution, and the duration is 60 min. The effluent is discharged into the storage tank.

[0040] S2. Then close the injection pump of 0.07 mol / L hydrochloric acid solution, open the injection pump of the organic acid treatment liquid, and the duration is 30 min. Among them, the organic acid treatment liquid contains 0.03 mol / L of acrylic acid and 0.1 wt% of α-olefin sulfonate.

[0041] S3. Then close the injection pump of the organic acid treatment liquid, open the circulation pump of 0.071 mol / L sodium hydroxide solution, and the duration is 80 min; finally, close the circulation pump of 0.071 mol / L sodium hydroxide solution, open the injection pump of deionized water, sample and analyze that the effluent pH = 7.0, complete the regeneration of the resin, and the ion exchange column is ready for use.

[0042] Embodiment 2

[0043] A regeneration method for a sodium carboxylate gel-type ion exchange resin, the steps of which are as follows:

[0044] S1. After the ion exchange column filled with the sodium carboxylate gel-type ion exchange resin adsorbs heavy metals to saturation, regeneration operation is carried out. Close the sewage inlet valve of the ion exchange column, open the injection pump of 0.1 mol / L hydrochloric acid solution to inject hydrochloric acid solution, and the duration is 45 min. The effluent is discharged into the storage tank.

[0045] S2. Subsequently, close the injection pump for 0.1 mol / L hydrochloric acid solution, and turn on the injection pump for the organic acid treatment solution for 25 min. Among them, the organic acid treatment solution contains 0.03 mol / L of benzenesulfonic acid and 0.3 wt% of sodium dodecylbenzenesulfonate.

[0046] S3. Subsequently, close the injection pump for the organic acid treatment solution, and turn on the circulation pump for 0.103 mol / L sodium hydroxide solution for 60 min; finally, close the circulation pump for 0.103 mol / L sodium hydroxide solution, turn on the injection pump for deionized water, and sample and analyze that the pH of the effluent is 7.0 to complete the regeneration of the resin, and the ion exchange column is ready for use.

[0047] Example 3

[0048] A regeneration method for a sodium carboxylate gel-type ion exchange resin, the steps of which are as follows:

[0049] S1. After the ion exchange column filled with sodium carboxylate gel-type ion exchange resin adsorbs heavy metals until saturated, perform a regeneration operation. Close the sewage inlet valve of the ion exchange column, turn on the injection pump for 0.13 mol / L hydrochloric acid solution to introduce hydrochloric acid solution for 30 min, and discharge the effluent into the storage tank.

[0050] S2. Subsequently, close the injection pump for 0.13 mol / L hydrochloric acid solution, and turn on the injection pump for the organic acid treatment solution for 20 min. Among them, the organic acid treatment solution contains 0.05 mol / L of benzenesulfonic acid and 0.5 wt% of sodium vinylsulfonate.

[0051] S3. Subsequently, close the injection pump for the organic acid treatment solution, turn on the circulation pump for 0.153 mol / L sodium hydroxide solution for 45 min; finally, close the circulation pump for 0.103 mol / L sodium hydroxide solution, turn on the injection pump for deionized water, and sample and analyze that the pH of the effluent is 7.0 to complete the regeneration of the resin, and the ion exchange column is ready for use.

[0052] Comparative Example 4

[0053] The difference between this example and Example 2 is that the organic acid treatment solution contains 0.005 mol / L of benzenesulfonic acid and 0.3 wt% of sodium dodecylbenzenesulfonate, and the others are the same as Example 2.

[0054] Example 5

[0055] The difference between this example and Example 2 is that the organic acid treatment solution contains 0.01 mol / L of benzenesulfonic acid and 0.3 wt% of sodium dodecylbenzenesulfonate, and the others are the same as Example 2.

[0056] Example 6

[0057] The difference between this example and Example 2 is that the organic acid treatment solution contains 0.05 mol / L of benzenesulfonic acid and 0.3 wt% of sodium dodecylbenzenesulfonate, and the others are the same as in Example 2.

[0058] Comparative Example 7

[0059] The difference between this example and Example 2 is that the organic acid treatment solution contains 0.07 mol / L of benzenesulfonic acid and 0.3 wt% of sodium dodecylbenzenesulfonate, and the others are the same as in Example 2.

[0060] Example 8

[0061] The difference between this example and Example 8 is that the organic acid treatment solution contains 0.05 mol / L of benzenesulfonic acid, 0.3 wt% of sodium dodecylbenzenesulfonate and 0.02 mol / L of phenol, and the others are the same as in Example 8.

[0062] Example 9

[0063] The difference between this example and Example 8 is that the organic acid treatment solution is preheated to 55 °C and then fed into the ion exchange column. The specific method is as follows:

[0064] A regeneration method for a carboxylate gel-type ion exchange resin, and its steps are as follows:

[0065] S1. The same as in Example 2.

[0066] S2. The organic acid treatment solution is preheated to 55 °C, then the injection pump for the 0.1 mol / L hydrochloric acid solution is closed, and the injection pump for the organic acid treatment solution is opened for 25 minutes. Among them, the organic acid treatment solution is the same as in Example 8.

[0067] S3. The same as in Example 2.

[0068] Comparative Example

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 2 is that the organic acid treatment solution contains 0.05 mol / L of benzenesulfonic acid and 0.02 mol / L of phenol, without a surfactant, and the others are the same as in Example 2.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 2 is that the organic acid treatment solution contains 0.3 wt% of sodium dodecylbenzenesulfonate and 0.02 mol / L of phenol, without benzenesulfonic acid, and the others are the same as in Example 2.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 2 is that the regeneration method in this comparative example does not treat the ion exchange column with an organic acid treatment solution. Specifically:

[0075] A regeneration method for a sodium carboxylate gel-type ion exchange resin, the steps of which are:

[0076] S1. After the ion exchange column filled with the sodium carboxylate gel-type ion exchange resin adsorbs heavy metals until saturation, a regeneration operation is carried out. Close the sewage inlet valve of the ion exchange column, open the injection pump of 0.1 mol / L hydrochloric acid solution to introduce hydrochloric acid solution for 45 minutes, and discharge the effluent into the storage tank.

[0077] S2. Subsequently, close the injection pump of 0.1 mol / L hydrochloric acid solution, open the circulation pump of 0.103 mol / L sodium hydroxide solution for 60 minutes; finally, close the circulation pump of 0.103 mol / L sodium hydroxide solution, open the injection pump of deionized water, sample and analyze that the effluent pH = 7.0, complete the regeneration of the resin, and the ion exchange column is ready for use.

[0078] Performance detection test

[0079] 1. Refer to the national standard GB / T 36769-2018 to determine the regeneration conversion rate of the sodium carboxylate gel-type ion exchange resin. The specific results are shown in Table 1.

[0080] Table 1 Regeneration conversion rate of sodium carboxylate gel-type ion exchange resin in different implementation schemes

[0081]

[0082] It can be seen from the data results of Examples and Comparative Example 3 in Table 1 that after treating the sodium carboxylate gel-type ion exchange resin with the organic acid treatment solution of the present application, the regeneration conversion rate of the sodium carboxylate gel-type ion exchange resin is significantly improved. Among them, from the data results of Example 2 and Comparative Example 4, Examples 5-6 and Comparative Example 7, it is seen that when treating the sodium carboxylate gel-type ion exchange resin with the organic acid treatment solution of the present application, the content of strong organic acid in the organic acid treatment solution is recommended to be controlled within the range of 0.01-0.05 mol / L, otherwise it will affect the regeneration effect of the sodium carboxylate gel-type ion exchange resin. And Examples 2 and 8 show that adding both strong organic acid and weak organic acid in the organic acid treatment solution can further improve the regeneration rate of the sodium carboxylate gel-type ion exchange resin; in addition, Example 9 heats the organic acid treatment solution to further enhance the treatment effect of the organic acid treatment solution, so that the regeneration rate of the sodium carboxylate gel-type ion exchange resin is improved.

[0083] In this solution, the surfactant and organic acid in the organic acid treatment liquid interact with each other and are indispensable. The surfactant improves the interaction relationship between the organic acid treatment liquid and COD, making it easier for COD to form a stable interaction force with the organic acid, so that COD is carried away by the organic acid treatment liquid, thereby improving the regeneration rate of the sodium carboxylate gel-type ion exchange resin.

[0084] 2. Measure the COD in the effluent after treatment with the organic acid treatment liquid Cr value, and the specific results are shown in Table 2.

[0085] Table 2 COD in the effluent after treatment with the organic acid treatment liquid in different embodiments Cr value

[0086] Embodiment Example 2 Example 8 Example 9 Comparative Example 3 <![CDATA[COD Cr (mg / L)]]> 15.45 18.64 20.31 5.16

[0087] The wastewater treated by the sodium carboxylate gel-type ion exchange resin of this application contains 40 mg / L of COD. After this wastewater passes through the new sodium carboxylate gel-type ion exchange resin, 25-50 wt% of the COD will remain in the sodium carboxylate gel-type ion exchange resin. It can be seen from the data results in Table 2 that a large amount of COD remaining in the sodium carboxylate gel-type ion exchange resin can be removed by the regeneration method of this application. The data results of Example 2 and Comparative Example 3 show that the COD removal amount of the regeneration method of this application is significantly improved. In Example 8, after strengthening both the organic acid and the weak organic acid in the organic acid treatment liquid, the COD removal effect is further improved; in addition, the method of preheating the organic acid treatment liquid in Example 9 can also further improve the COD removal effect.

[0088] This specific embodiment is only an explanation of this application, and it does not limit this application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A regeneration method for a sodium carboxylate gel-type ion exchange resin, characterized in that, It includes the following steps: Continuously introduce hydrochloric acid solution into the carboxylate gel-type ion exchange resin saturated with adsorption, then continuously introduce the organic acid treatment solution into the carboxylate gel-type ion exchange resin, and finally continuously introduce the alkali solution into the carboxylate gel-type ion exchange resin and wash with water until the effluent is neutral; Among them, the organic acid treatment solution contains a surfactant, the organic acid in the organic acid treatment solution includes strong organic acids, and the strong organic acids are selected from at least one of benzenesulfonic acid and acrylic acid; the organic acid also includes weak organic acids; the weak organic acids are selected from at least one of phenol and acetic acid; The molar ratio of the weak organic acid to the strong organic acid is (0.2 - 0.5):1; The content of the strong organic acid in the organic acid treatment solution is 0.01 - 0.05 mol / L; The treatment time of the organic acid treatment solution is 20 - 30 min; The surfactant is selected from at least one of sodium dodecylbenzenesulfonate, α-olefin sulfonate and vinyl sulfonate; The organic acid treatment solution is heated and then introduced into the carboxylate gel-type ion exchange resin, and the heating temperature is 45 - 60 °C; The carboxylate gel-type ion exchange resin is an exchange resin that has treated electroplating wastewater.

2. The regeneration method of a sodium carboxylate gel-type ion exchange resin according to claim 1, characterized in that, The time for continuously introducing the hydrochloric acid solution into the carboxylate gel-type ion exchange resin is 30 - 60 min, and the concentration of hydrochloric acid in the hydrochloric acid solution is 0.07 - 0.13 mol / L.

3. The regeneration method of a sodium carboxylate gel-type ion exchange resin according to claim 1 or 2, characterized in that, The time for continuously introducing the alkali solution into the carboxylate gel-type ion exchange resin is 45 - 80 min; the concentration of the alkali in the alkali solution is 0.071 - 0.153 mol / L.

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