Phytic acid-based chelating adsorption resin, preparation method thereof and application of phytic acid-based chelating adsorption resin in adsorption of Cr (VI) in wastewater

Abstract

The invention discloses phytic acid-based chelating adsorption resin, a preparation method thereof and application of the phytic acid-based chelating adsorption resin in Cr (VI) adsorption. The phytic acid-based chelating adsorption resin is obtained through aqueous solution free radical polymerization of phytic acid-based functional monomers, acrylamide and a cross-linking agent under the action of an initiator, the adsorption capacity and the stability of the adsorption resin on heavy metal ions are improved by utilizing the strong chelating property, the oxidation resistance, the color protection property and the like of a plurality of phosphate groups of the phytic acid, and the defects that the adsorption capacity of polyacrylamide resin on the heavy metal ions is low, the acid resistance is weak and an aqueous solution of the phytic acid easily causes secondary pollution on a water body are overcome; the raw materials used in the preparation method are cheap and easy to obtain, the synthesis process is simple, green and environment-friendly, large-scale production is easy, and the preparation method has a very good market prospect.

Description

Technical Field

[0001] The invention relates to wastewater treatment and belongs to the technical field, and specifically relates to a phytic acid-based chelated adsorption resin and a preparation method thereof and application in adsorbing Cr(VI). Background Art

[0002] With the rapid development of global industrialization, heavy metal pollution poses a serious threat to human health and the environment. Among them, Cr(VI) is considered a carcinogen by the International Agency for Research on Cancer because it is mutagenic and teratogenic. Cr(VI) is a heavy metal ion that exists in large quantities in wastewater from electroplating, dyes, leather, textiles and other industries. It is highly toxic and carcinogenic, and is difficult to biodegrade, seriously endangering the ecological environment and human health.

[0003] At present, the methods for removing Cr(VI) include chemical precipitation, electrochemical method, ion exchange method, reverse osmosis, photocatalysis, biochemistry, adsorption, etc. The adsorption method has the advantages of simplicity, convenience, low cost, strong selectivity, and good treatment effect. It is especially suitable for removing low-concentration heavy metal ions and has been widely used to treat wastewater containing Cr(VI). Resin adsorption is currently the most environmentally friendly adsorption method. Its adsorption mechanism is mainly to use various active groups of resin such as hydroxyl, carboxyl, phosphate, and amino groups to "capture" heavy metal ions in wastewater through chelation. These functional resin materials can effectively adsorb heavy metal ions.

[0004] Phytic acid is an organic polyacid extracted from plants. The multiple phosphate groups in its molecular structure have strong chelating properties and strong binding ability to metal ions. However, since phytic acid is water-soluble, although it can form a complex with metal ions, it cannot effectively remove metal ions from water bodies. If used improperly, it will cause secondary pollution of water bodies. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] The present invention is proposed to solve the problems that polyacrylamide resin has low adsorption capacity for heavy metal ions, weak acid resistance and phytic acid aqueous solution is easy to cause secondary pollution to water bodies.

[0007] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a phytic acid-based chelated adsorption resin.

[0008] In order to solve the above technical problems, the present invention provides the following technical solution:

[0009] a. A repeating unit phytic acid functional monomer PA-GMA having a structural formula of phytic acid PA and glycidyl methacrylate GMA as shown in formula (I);

[0010]

[0011] b. a repeating unit of acrylamide AM connected to the terminal C=C double bond of the repeating unit of the phytic acid functional monomer PA-GMA, wherein the structural formula is shown in formula (II), wherein n represents the number of repeating units, and n is a non-zero integer;

[0012]

[0013] c. The molar ratio of phytic acid PA to glycidyl methacrylate GMA in the repeating unit phytic acid functional monomer PA-GMA is 1:3-6;

[0014] d. The molar ratio of the repeating unit phytic acid functional monomer PA-GMA to the repeating unit acrylamide AM is 1:0-5.

[0015] Another object of the present invention is to provide a method for preparing a phytic acid-based chelated adsorption resin.

[0016] In order to solve the above technical problems, the present invention provides the following technical scheme: comprising: stirring and dissolving phytic acid functional monomer PA-GMA, acrylamide AM, a crosslinking agent and distilled water, passing nitrogen for 30 minutes to 60 minutes, adding an initiator, and heating the reaction in a water bath under nitrogen protection to obtain a phytic acid chelating adsorption resin.

[0017] As a preferred embodiment of the method for preparing the phytic acid-based chelated adsorption resin of the present invention, the method for preparing the phytic acid-based functional monomer comprises:

[0018] As a preferred embodiment of the method for preparing the phytic acid-based chelated adsorption resin of the present invention, the cross-linking agent includes one of N,N-methylenebisacrylamide, N-hydroxymethylacrylamide, ethylene glycol bisacryl ester, and trimethylolpropane triene acrylate.

[0019] As a preferred embodiment of the method for preparing the phytic acid-based chelated adsorption resin of the present invention, the initiator is composed of a water-soluble oxidant and a reductant, wherein the oxidant includes one or more of potassium persulfate, ammonium persulfate, and hydrogen peroxide;

[0020] The reducing agent includes one or more of sulfite, bisulfite, ascorbic acid and pyrosulfite.

[0021] As a preferred embodiment of the method for preparing the phytic acid-based chelated adsorption resin of the present invention, the molar ratio of the oxidant to the reductant is greater than 1.

[0022] As a preferred embodiment of the method for preparing the phytic acid-based chelated adsorption resin of the present invention, the reaction temperature of the water bath heating reaction is 20 to 50° C., and the reaction time is 6 to 12 hours.

[0023] Another object of the present invention is to provide a method for adsorbing Cr(VI) in wastewater.

[0024] To solve the above technical problems, the present invention provides the following technical solution: adding phytic acid-based chelated adsorption resin to wastewater containing Cr(VI) in an amount of 25-40 g / L, adjusting the pH of the wastewater and stirring for adsorption treatment to achieve adsorption of Cr(VI) in the wastewater.

[0025] As a preferred embodiment of the method for adsorbing Cr(VI) in wastewater of the present invention, the pH of the wastewater containing Cr(VI) is adjusted to 2-6.

[0026] As a preferred embodiment of the method for adsorbing Cr(VI) in wastewater of the present invention, the stirring speed of the adsorption treatment is 100-200 r / min, the temperature of the adsorption treatment is 10-70°C, and the time of the adsorption treatment is 30-300 min.

[0027] Beneficial effects of the present invention:

[0028] The present application innovatively proposes a phytic acid-based chelated adsorption resin, a preparation method thereof, and an application in the adsorption of Cr(VI), utilizing the strong chelating, antioxidant and color protection properties of multiple phosphate groups of phytic acid to improve the adsorption capacity and stability of the adsorption resin for heavy metal ions, overcoming the shortcomings of polyacrylamide resin adsorption for heavy metal ions, such as low adsorption capacity, weak acid resistance, and the secondary pollution of water bodies caused by aqueous solutions of phytic acid. The raw materials used in the preparation method are cheap and easily available, the synthesis process is simple, green and environmentally friendly, easy to mass produce, and has good market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0030] Figure 1 This is a schematic diagram of the process for preparing phytic acid-based chelated adsorption resin according to Example 2 of the present invention.

[0031] Figure 2 This is the infrared spectrum of the phytic acid-based chelated adsorption resin obtained in Example 2 of the present invention.

[0032] Figure 3 The present invention shows the influence of different solution pH on the adsorption of Cr(VI) by phytic acid-based chelating adsorption resin.

[0033] Figure 4 The figure shows the influence of different adsorption times on the adsorption effect of Cr(VI) by phytic acid chelating adsorption resin of the present invention.

[0034] Figure 5 The figure shows the effect of the dosage of the phytic acid-based chelated adsorption resin on the adsorption of Cr(VI). DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0038] Unless otherwise specified, the raw materials used in the present invention are all commercially available in the art.

[0039] The preparation of the phytic acid functional monomer (PA-GMA) in the present invention is as follows:

[0040] In a 500mL four-necked round-bottom flask equipped with a thermometer, an electric stirrer, a constant pressure dropping funnel, and a nitrogen conduit, 0.15mol of a phytic acid solution of 70% phytic acid, 1% of urea, and 0.1% of p-hydroxyanisole were added and stirred to dissolve, and then heated to 30°C in a water bath. Under nitrogen protection, 0.9mol of glycidyl methacrylate was added to the constant pressure dropping funnel. Under stirring, glycidyl methacrylate was added dropwise within 2 hours, and the dropping speed was strictly controlled to ensure that the temperature did not exceed 40°C during the dropping process. After all the additions were completed, the reaction was carried out at a constant temperature of 45°C for 5 hours, and the reaction solution became homogeneous, and the reaction was stopped to obtain PA-GMA.

[0041] Example 1

[0042] This embodiment provides a method for preparing a phytic acid-based chelating adsorption resin, specifically:

[0043] 1) Preparation of phytic acid functional monomer (PA-GMA):

[0044] In a 500mL four-necked round-bottom flask equipped with a thermometer, an electric stirrer, a constant pressure dropping funnel, and a nitrogen conduit, 0.15mol of a phytic acid solution of 70% phytic acid, 1% of urea, and 0.1% of p-hydroxyanisole were added and stirred to dissolve, and then heated to 30°C in a water bath. Under nitrogen protection, 0.9mol of glycidyl methacrylate was added to the constant pressure dropping funnel. Under stirring, glycidyl methacrylate was added dropwise within 2 hours, and the dropping speed was strictly controlled to ensure that the temperature did not exceed 40°C during the dropping process. After all the additions were completed, the reaction was carried out at a constant temperature of 45°C for 5 hours, and the reaction solution became homogeneous, and the reaction was stopped to obtain PA-GMA.

[0045] 2) Preparation of phytic acid chelated adsorption resin:

[0046] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer and a nitrogen inlet, add 60.00gPA-GMA, 0.90gN,N'-methylenebisacrylamide and 75.00gdistilled water, stir and dissolve, pass nitrogen for 30 minutes, then add 0.25g sodium bisulfite and 0.25g ammonium persulfate in sequence, heat to 30°C in a water bath, and react for 6 hours under nitrogen protection to obtain a phytic acid-based chelating adsorption resin.

[0047] Example 2

[0048] Reference Figure 1 The present embodiment is different from the embodiment 1 in that the preparation of the phytic acid chelating adsorption resin in step 2) is adjusted by introducing acrylamide, specifically:

[0049] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit, 36.00g PA-GMA, 24g acrylamide, 0.90g N,N'-methylenebisacrylamide, and 75.00g distilled water were added and stirred to dissolve, and then nitrogen was passed for 30min, and then 0.25g sodium bisulfite and 0.25g ammonium persulfate were added in sequence, heated to 30°C in a water bath, and reacted for 6h under nitrogen protection to obtain the phytic acid chelating adsorption resin of this embodiment.

[0050] Figure 2 The infrared spectrum of the phytic acid chelate adsorption resin prepared in this example shows that the infrared spectrum has a wavelength of 2950 cm －1 The peaks appearing at 1720 cm-1 are the -CH- symmetric and antisymmetric stretching vibration absorption peaks of polyacrylamide. －1 and 1630cm－1 The nearby peaks are the stretching vibration absorption peaks of -C=O and CN in polyacrylamide, 1172 cm －1 The absorption peak near 1049 cm is attributed to the P=O stretching vibration peak of phytic acid. －1 The peak at is the typical stretching vibration absorption peak of phytic acid POC, and the infrared spectrum shows the successful preparation of phytic acid-based chelating adsorption resin.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that the preparation of step 2) phytic acid chelate adsorption resin is adjusted, specifically:

[0053] A 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit was equipped with 30.00gPA-GMA, 30gacrylamide, 0.90gN,N'-methylenebisacrylamide, and 75.00gdistilled water. After stirring and dissolving, nitrogen was passed through for 30min, and then 0.25g sodium bisulfite and 0.25g ammonium persulfate were added in sequence. The mixture was heated to 30°C in a water bath and reacted for 6h under nitrogen protection to obtain the phytic acid chelating adsorption resin of the present embodiment.

[0054] Example 4

[0055] The difference between this embodiment and embodiment 1 is that the preparation of step 2) phytic acid chelate adsorption resin is adjusted, specifically:

[0056] In a 500mL three-necked round-bottom flask equipped with a thermometer, an electric stirrer, and a nitrogen conduit, 24.00g PA-GMA, 36g acrylamide, 0.90g N,N'-methylenebisacrylamide, and 75.00g distilled water were added and stirred to dissolve, and then nitrogen was passed for 30min, and then 0.25g sodium bisulfite and 0.25g ammonium persulfate were added in sequence, heated to 30°C in a water bath, and reacted for 6h under nitrogen protection to obtain the phytic acid chelating adsorption resin of this embodiment.

[0057] Application Testing

[0058] Take 50mL of potassium dichromate solution (10mg / L) and place it in a 100mL stoppered conical flask. Add a certain amount of phytic acid chelating adsorption resin prepared in the above example. Under certain temperature and pH conditions, shake at 150r / min for 250min, let it stand for 30min, and measure the supernatant after separation. The concentration of Cr(VI) in the supernatant is measured by diphenylcarbazide spectrophotometry. The experimental results are as follows: Figures 3 to 5 shown.

[0059] Figure 3The effect of different solution pH on the removal rate under the conditions of phytic acid chelating adsorption resin addition amount of 10g / L, temperature of 20℃, and adsorption time of 250min. Figure 4 The effect of different reaction temperatures on the removal rate under the conditions of 10 g / L phytic acid chelating adsorption resin addition, pH 2, and adsorption time of 250 min. Figure 5 Under the conditions of pH 2, temperature 20℃ and adsorption time 250min, the effect of different amounts of phytic acid chelating adsorption resin added on the removal rate.

[0060] from Figures 3 to 5 It can be seen that the phytic acid chelate adsorption resin prepared in the present application has a higher removal rate of Cr(VI) with time extension and temperature increase, and increases first and then decreases with pH increase. When pH = 2, the Cr(VI) removal rate reaches the highest. When the amount of phytic acid chelate adsorption resin is 40g / L, under the same conditions, the sample of Example 1 has the best removal rate of Cr(VI), and the removal rate can reach 95.5%.

[0061] In summary, the present invention discloses a phytic acid-based chelated adsorption resin, a preparation method thereof, and an application in the adsorption of Cr(VI), and utilizes the strong chelating, antioxidant and color protection properties of multiple phosphate groups of phytic acid to improve the adsorption capacity and stability of the adsorption resin for heavy metal ions, thereby overcoming the shortcomings of polyacrylamide resin adsorption for heavy metal ions, such as low adsorption capacity, weak acid resistance, and the secondary pollution of water bodies caused by aqueous solutions of phytic acid. The raw materials used in the preparation method are cheap and easily available, the synthesis process is simple, green and environmentally friendly, and easy to scale up production.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A phytic acid-based chelated adsorption resin, characterized in that: It is composed of: a. A repeating unit phytic acid functional monomer PA-GMA having a structural formula of phytic acid PA and glycidyl methacrylate GMA as shown in formula (I); b. a repeating unit of acrylamide AM connected to the terminal C=C double bond of the repeating unit of the phytic acid functional monomer PA-GMA, wherein the structural formula is shown in formula (II), wherein n represents the number of repeating units, and n is a non-zero integer; c. The molar ratio of phytic acid PA to glycidyl methacrylate GMA in the repeating unit phytic acid functional monomer PA-GMA is 1:3-6; d. The molar ratio of the repeating unit phytic acid functional monomer PA-GMA to the repeating unit acrylamide AM is 1:0-5.

2. The method for preparing a phytic acid-based chelated adsorption resin according to claim 1, wherein: The method comprises the following steps: stirring and dissolving phytic acid functional monomer PA-GMA, acrylamide AM, a crosslinking agent and distilled water, passing nitrogen for 30 to 60 minutes, adding an initiator, and heating in a water bath under nitrogen protection to react, thereby obtaining a phytic acid chelating adsorption resin.

3. The method for preparing a phytic acid-based chelated adsorption resin as claimed in claim 2, wherein: The crosslinking agent includes one of N,N-methylenebisacrylamide, N-hydroxymethylacrylamide, ethylene glycol bisacryl ester, and trimethylolpropane triene acrylate.

4. The method for preparing a phytic acid-based chelated adsorption resin according to claim 2, wherein: The initiator is composed of a water-soluble oxidant and a reductant, wherein the oxidant includes one or more of potassium persulfate, ammonium persulfate, and hydrogen peroxide; The reducing agent includes one or more of sulfite, bisulfite, ascorbic acid and pyrosulfite.

5. The method for preparing a phytic acid-based chelated adsorption resin as claimed in claim 4, characterized in that: The molar ratio of the oxidizing agent to the reducing agent is >1.

6. The method for preparing the phytic acid-based chelated adsorption resin according to claim 2, wherein: The reaction temperature of the water bath heating reaction is 20-50° C., and the reaction time is 6-12 hours.

7. A method for adsorbing Cr(VI) in wastewater, characterized in that: Use the phytic acid chelated adsorption resin described in claim 1.

8. The method for adsorbing Cr(VI) in wastewater according to claim 7, characterized in that: The phytic acid-based chelating adsorption resin is added to the wastewater containing Cr(VI) at a dosage of 25-40 g / L, and the pH value of the wastewater is adjusted and then stirred for adsorption treatment to achieve the adsorption of Cr(VI) in the wastewater.

9. The method for adsorbing Cr(VI) in wastewater according to claim 8, characterized in that: The pH of the Cr(VI)-containing wastewater is adjusted to 2-6.

10. The method for adsorbing Cr(VI) in wastewater according to claim 8, characterized in that: The stirring speed of the adsorption treatment is 100-200 r / min, the temperature of the adsorption treatment is 10-70° C., and the time of the adsorption treatment is 30-300 min.

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