PTA wastewater treatment method

Abstract

The invention provides a PTA wastewater treatment method, which comprises: carrying out biodegradation treatment and membrane separation treatment on to-be-treated PTA wastewater, carrying out adsorption treatment through an adsorption resin, and carrying out ultrafiltration and reverse osmosis treatment, wherein the adsorption resin is formed by compounding zeolite and a polymer, and is obtained by the following method: uniformly mixing zeolite, styrene, divinylbenzene, an initiator, a pore-foaming agent and 3-methyl-5-vinylpyridine to obtain an oil phase; uniformly mixing water and a dispersing agent to obtain a water phase; and uniformly mixing the oil phase and the water phase, stirring, and carrying out polymerization reaction to obtain the adsorption resin. According to the PTA wastewater treatment method disclosed by the invention, a physical process and a biochemical process are combined, so that pollutants such as bromide ions can be effectively removed, and the wastewater recycling requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly to a method for treating PTA wastewater. Background Art

[0002] Purified terephthalic acid, also known as Pure Terephthalic Acid (PTA), is an organic compound, usually in the form of white crystals or powder. Industrially, purified terephthalic acid is mainly produced by liquid-phase oxidation of p-xylene to produce crude terephthalic acid, and then through steps such as hydrogenation refining, crystallization, separation, and drying. Purified terephthalic acid (PTA) is an important chemical intermediate, mainly used in the production of polyester fibers, polyester bottles, and certain engineering plastics, and is also an important raw material for intermediates such as dyes and drugs.

[0003] A large amount of production wastewater is generated during the PTA production process, mainly including mixed wastewater such as reverse osmosis concentrate from the PTA wastewater treatment station, desalted water station drainage, and boiler island desulfurization wastewater. The water quality and quantity of this wastewater vary greatly, with complex components, high salt content, acidic wastewater, and high COD content, belonging to difficult-to-biodegrade chemical wastewater. The wastewater contains a large amount of aromatic organic acids and inorganic ions. Among them, the aromatic organic acids mainly include p-carboxybenzaldehyde, benzoic acid, p-toluic acid, isophthalic acid, trimellitic acid, phthalic acid, and terephthalic acid, etc., and the inorganic ions mainly include cobalt, manganese, iron, calcium, magnesium, bromine ions, etc.

[0004] Currently, when performing in-depth treatment on purified terephthalic acid refining wastewater, physical adsorption is one of the key treatment steps, which can remove most of the aromatic organic acids and inorganic ions. However, it faces the following problems: The salt content in the purified terephthalic acid refining wastewater is high, and the molecular structure of the adsorption material is easily damaged under high salt content conditions, usually with a short service life. And when using the adsorption material to remove bromine ions, the treatment effect of bromine ions is not good. In the subsequent membrane treatment process, bromine ions will accelerate the aging and pollution of the reverse osmosis membrane, resulting in a rapid decline in the performance of the reverse osmosis membrane, and even the phenomenon that the bromine ion content in the treated water exceeds the standard. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for treating PTA wastewater to solve the problems that it is difficult to effectively remove bromine ions in the adsorption step of the existing method for treating PTA wastewater and the short service life of the adsorption material.

[0006] The present invention provides the following technical solutions: A method for treating PTA wastewater, comprising the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment, membrane separation treatment, then performing adsorption treatment through an adsorption resin, and then performing ultrafiltration and reverse osmosis treatment; Among them, the adsorption resin is composed of zeolite and polymer, and is obtained by the following method: (1) Mix zeolite, styrene, divinylbenzene, initiator, pore-forming agent, and 3-methyl-5-vinylpyridine evenly to obtain an oil phase; (2) Mix water and dispersant evenly to obtain an aqueous phase; (3) Mix the oil phase in step (1) with the aqueous phase in step (2) evenly, stir, and then carry out a polymerization reaction to obtain an adsorption resin.

[0007] Preferably, in step (1), the initiator is azobisisobutyronitrile; the pore-forming agent is one of toluene and xylene; the dispersant is one of hydroxyethyl cellulose, hydroxymethyl cellulose, and polyvinyl alcohol.

[0008] Preferably, in step (1), the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:(2 - 8):(0.5 - 2):(0.08 - 0.20):(1.8 - 3.6); Optionally, in step (2), in the aqueous phase, the mass fraction of the dispersant is 0.3 - 0.8 wt%; Optionally, in step (3), the volume ratio of the oil phase to the aqueous phase is 1:(5 - 8).

[0009] Preferably, in step (1), the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:(0.2 - 1.0).

[0010] Preferably, step (1) specifically includes the following steps: First, mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent evenly, stir at 15 - 35 °C for 1 - 3 h, and then add styrene, divinylbenzene, and initiator thereto, and mix evenly at 15 - 35 °C to obtain an oil phase.

[0011] Preferably, step (3) specifically includes the following steps: At 15 - 35 °C, add the oil phase to the aqueous phase, mix evenly, then raise the temperature to 70 - 100 °C at a rate of 1 - 3 °C / min, stir and react for 8 - 12 h, and obtain the adsorption resin through filtration, washing, and drying.

[0012] Preferably, the preparation method of the adsorption resin further includes the following steps: Add the adsorption resin obtained in step (3) to N,N-dimethylformamide, then add 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mix evenly, stir and react at 50 - 70 °C for 6 - 8 h, and obtain the product through filtration and washing.

[0013] Preferably, the concentration of the adsorption resin in the N,N-dimethylformamide is 6-10 mg / ml; the mass ratio of the adsorption resin, 1,4-dimercaptophthalazine, and azobisisobutyronitrile is 1:(1.5-2.5):(0.01-0.03).

[0014] Preferably, the method for preparing the adsorption resin further includes the step of adding 1,3-dimercaptopropane; the mass ratio of 1,3-dimercaptopropane to 1,4-dimercaptophthalazine is (0.03-0.08):1.

[0015] Preferably, the adsorption treatment is to install the adsorption resin on a resin bed for dynamic adsorption at a flow rate of 1-4 BV / h for 1-4 h.

[0016] Preferably, the biodegradation treatment is carried out in a bioreactor for 24-96 h.

[0017] Preferably, the membrane separation treatment is carried out using a microfiltration membrane with a pore size of 0.1-1 μm.

[0018] Preferably, the ultrafiltration and reverse osmosis treatments are carried out using an ultrafiltration membrane with a pore size of 0.01 μm and a reverse osmosis membrane with a pore size of 0.5-10 nm.

[0019] The above solution of the present invention has at least the following beneficial effects: (1) The method for treating PTA wastewater of the present invention includes the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment and membrane separation treatment, then performing adsorption treatment with an adsorption resin, and then performing ultrafiltration and reverse osmosis treatments; wherein, the adsorption resin is composed of a composite of zeolite and a polymer and is obtained by the following method: mixing zeolite, styrene, divinylbenzene, an initiator, a pore-forming agent, and 3-methyl-5-vinylpyridine uniformly to obtain an oil phase; mixing water and a dispersant uniformly to obtain an aqueous phase; mixing the oil phase and the aqueous phase uniformly, stirring, and then performing a polymerization reaction to obtain the adsorption resin. The method for treating PTA wastewater of the present invention combines a physical process with a biochemical process, can effectively remove pollutants such as bromide ions, and meets the requirements for wastewater reuse. Among them, the biodegradation can remove most of the suspended solids and organic matter in a high-salt environment, reducing the possibility of fouling during subsequent membrane separation treatment due to excessive suspended solids. The adsorption treatment can selectively adsorb bromide ions from the wastewater through the adsorption resin. After removing the bromide ions, the damage of the bromide ions to the membrane used in the subsequent ultrafiltration and reverse osmosis processes can be greatly weakened. After the ultrafiltration and reverse osmosis treatments, the wastewater is ensured to reach the quality of reusable water, realizing the recycling of wastewater.

[0020] (2)The treatment method of PTA wastewater of the present invention. The adsorption resin is obtained by a polymerization reaction after mixing an oil phase and an aqueous phase formed by zeolite, styrene, divinylbenzene, an initiator, and a pore-forming agent, and can obtain a resin with good selectivity for bromide ions, a macroporous structure with uniform distribution, and a large specific surface area. In particular, the oil phase further includes 3-methyl-5-vinylpyridine. The pyridine group of the 3-methyl-5-vinylpyridine has alkalinity and can combine with groups such as hydroxyl groups (-OH) on the surface of the zeolite when contacting the zeolite, thereby introducing the pyridine group onto the surface of the zeolite, realizing the modification of the zeolite, and making its surface carry active centers capable of initiating the polymerization of styrene. When styrene and divinylbenzene undergo a polymerization reaction under the action of an initiator, they interact with the surface of the zeolite to form a crosslinked structure. Since the 3-methyl-5-vinylpyridine participates in the polymerization reaction, the zeolite and the polymer are more closely combined together, so that the obtained adsorption resin has enhanced ability to resist swelling and dissolution under different environmental conditions, improving the chemical stability and mechanical stability of the adsorption resin. At the same time, the adsorption selectivity and adsorption capacity for bromide ions are also greatly improved. A higher adsorption efficiency can be achieved, and the physicochemical properties are stable, and it is less affected by substances such as inorganic salts.

[0021] (3)The treatment method of PTA wastewater of the present invention. The preparation method of the adsorption resin further includes the following steps: adding the adsorption resin obtained in step (3) into N,N-dimethylformamide, and then adding 1,4-dimercapto-phthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 50-70 °C for 6-8 h, and filtering and washing to obtain the product. There are a certain amount of unreacted vinyl active ends in the adsorption resin, which can react with the mercapto groups of 1,4-dimercapto-phthalazine to achieve end-capping, making the polymer network of the resin more stable and enhancing its ability to resist salt ion erosion and chemical degradation. At the same time, mercapto groups and phthalazine rings with stable spatial structures are introduced. The presence of mercapto groups can improve the adsorption selectivity for bromide ions, and the spatial conformation formed by mercapto groups and phthalazine rings is conducive to realizing the specific adsorption of bromide ions and reducing the competitive adsorption of other ions. The phthalazine ring contains nitrogen atoms with relatively high electronegativity and has a conjugated system, which can adjust the charge distribution on the surface of the adsorption resin and reduce the damage of salt ions to the structure and functional groups of the adsorption resin, thereby improving the stability of the adsorption resin in high-salt water. Detailed implementation manners

[0022] In the embodiments of the present invention, those not specified in specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase. Raw materials from different manufacturers and models do not affect the implementation of the technical solution of the present invention and the realization of the technical effect.

[0023] Example 1

[0024] The treatment method of PTA wastewater in this embodiment includes the following steps: Perform biodegradation treatment on the PTA wastewater to be treated, react in a bioreactor for 24 hours, then perform membrane separation treatment using a microfiltration membrane with a pore size of 0.1 μm, then install the adsorption resin on the resin bed for dynamic adsorption at a flow rate of 3 BV / h for 1 hour, and then perform ultrafiltration using an ultrafiltration membrane with a pore size of 0.01 μm and reverse osmosis treatment using a reverse osmosis membrane with a pore size of 0.5 nm; Among them, the adsorption resin is composed of zeolite and polymer, and is obtained by the following method: (1) First, uniformly mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent, stir at 15 °C for 2 hours, then add styrene, divinylbenzene, and initiator thereto, and mix uniformly at 15 °C to obtain an oil phase; Among them, the initiator is azobisisobutyronitrile; the pore-forming agent is xylene; the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:5:0.5:0.20:1.8; the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:0.6.

[0025] (2) Uniformly mix water and dispersant to obtain an aqueous phase; Among them, the dispersant is hydroxyethyl cellulose. In the aqueous phase, the mass fraction of the dispersant is 0.3 wt%.

[0026] (3) At 15 °C, add the oil phase to the aqueous phase, mix uniformly, then heat up to 100 °C at a rate of 1 °C / min, stir and react for 8 hours, and obtain the adsorption resin through filtration, washing, and drying.

[0027] Among them, the volume ratio of the oil phase to the aqueous phase is 1:8.

[0028] Example 2

[0029] The treatment method of PTA wastewater in this embodiment includes the following steps: Perform biodegradation treatment on the PTA wastewater to be treated, react in a bioreactor for 96 hours, then perform membrane separation treatment using a microfiltration membrane with a pore size of 1 μm, then install the adsorption resin on the resin bed for dynamic adsorption at a flow rate of 4 BV / h for 4 hours, and then perform ultrafiltration using an ultrafiltration membrane with a pore size of 0.01 μm and reverse osmosis treatment using a reverse osmosis membrane with a pore size of 10 nm; Among them, the adsorption resin is composed of zeolite and polymer, and is obtained by the following method: (1) First, mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent evenly, stir at 35 °C for 3 h, then add styrene, divinylbenzene, and initiator thereto, and mix evenly at 35 °C to obtain an oil phase; Among them, the initiator is azobisisobutyronitrile; the pore-forming agent is xylene; the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:8:2:0.08:2.4; the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:0.2.

[0030] (2) Mix water and dispersant evenly to obtain an aqueous phase; Among them, the dispersant is hydroxymethylcellulose. In the aqueous phase, the mass fraction of the dispersant is 0.5 wt%.

[0031] (3) At 25 °C, add the oil phase to the aqueous phase, mix evenly, then heat up to 85 °C at a rate of 3 °C / min, stir and react for 12 h, and obtain the adsorption resin through filtration, washing, and drying.

[0032] Among them, the volume ratio of the oil phase to the aqueous phase is 1:6.

[0033] Example 3

[0034] The treatment method of PTA wastewater in this example includes the following steps: Perform biodegradation treatment on the PTA wastewater to be treated, react in a bioreactor for 60 h, then perform membrane separation treatment with a microfiltration membrane with a pore size of 0.5 μm, then install the adsorption resin on the resin bed for dynamic adsorption, adsorb at a flow rate of 1 BV / h for 3 h, and then perform ultrafiltration with an ultrafiltration membrane with a pore size of 0.01 μm and reverse osmosis treatment with a reverse osmosis membrane with a pore size of 5 nm; Among them, the adsorption resin is composed of zeolite and polymer and is obtained through the following method: (1) First, mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent evenly, stir at 25 °C for 1 h, then add styrene, divinylbenzene, and initiator thereto, and mix evenly at 25 °C to obtain an oil phase; Among them, the initiator is azobisisobutyronitrile; the pore-forming agent is toluene; the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:2:1.5:0.1:3.6; the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:1.

[0035] (2) Mix water and dispersant evenly to obtain an aqueous phase; Among them, the dispersant is polyvinyl alcohol. In the aqueous phase, the mass fraction of the dispersant is 0.8 wt%.

[0036] (3) At 35 °C, add the oil phase to the water phase, mix evenly, then heat it to 70 °C at a rate of 2 °C / min, stir and react for 10 h, and obtain the adsorption resin through filtration, washing, and drying.

[0037] Among them, the volume ratio of the oil phase to the water phase is 1:5.

[0038] Example 4

[0039] The treatment method of PTA wastewater in this example includes the following steps: Perform biodegradation treatment on the PTA wastewater to be treated, react in a bioreactor for 65 h, then perform membrane separation treatment using a microfiltration membrane with a pore size of 0.6 μm, then install the adsorption resin on the resin bed for dynamic adsorption at a flow rate of 4 BV / h for 2 h, and then perform ultrafiltration using an ultrafiltration membrane with a pore size of 0.01 μm and reverse osmosis treatment using a reverse osmosis membrane with a pore size of 8 nm; Among them, the adsorption resin is composed of zeolite and polymer and is obtained through the following method: (1) First, mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent evenly, stir at 25 °C for 3 h, then add styrene, divinylbenzene, and initiator to it, and mix evenly at 25 °C to obtain the oil phase; Among them, the initiator is azobisisobutyronitrile; the pore-forming agent is toluene; the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:6:1.5:0.12:2.5; the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:0.6.

[0040] (2) Mix water and dispersant evenly to obtain the water phase; Among them, the dispersant is polyvinyl alcohol. In the water phase, the mass fraction of the dispersant is 0.8 wt%.

[0041] (3) At 25 °C, add the oil phase to the water phase, mix evenly, then heat it to 90 °C at a rate of 3 °C / min, stir and react for 10 h, and obtain the adsorption resin through filtration, washing, and drying.

[0042] Among them, the volume ratio of the oil phase to the water phase is 1:8.

[0043] (4) Add the adsorption resin obtained in step (3) to N,N-dimethylformamide, then add 1,4-dimercaptophthalazine and azobisisobutyronitrile to it, mix evenly, stir and react at 60 °C for 8 h, and obtain it through filtration and washing.

[0044] Among them, the concentration of the adsorption resin in N,N-dimethylformamide is 8 mg / ml; the mass ratio of the adsorption resin, 1,4-dimercaptophthalazine, and azobisisobutyronitrile is 1:1.8:0.01.

[0045] Example 5

[0046] The method for treating PTA wastewater in this example is the same as that in Example 4, except that step (4) of the preparation method of the adsorption resin is different.

[0047] In this example, step (4) is specifically: adding the adsorption resin obtained in step (3) into N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 60°C for 8 h, and then filtering and washing to obtain the product.

[0048] Among them, the concentration of the adsorption resin in N,N-dimethylformamide is 10 mg / ml; the mass ratio of the adsorption resin, 1,4-dimercaptophthalazine, and azobisisobutyronitrile is 1:2.5:0.03.

[0049] Example 6

[0050] The method for treating PTA wastewater in this example is the same as that in Example 4, except that step (4) of the preparation method of the adsorption resin is different.

[0051] In this example, step (4) is specifically: adding the adsorption resin obtained in step (3) into N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 60°C for 8 h, and then filtering and washing to obtain the product.

[0052] Among them, the concentration of the adsorption resin in N,N-dimethylformamide is 6 mg / ml; the mass ratio of the adsorption resin, 1,4-dimercaptophthalazine, and azobisisobutyronitrile is 1:1.5:0.02.

[0053] Example 7

[0054] The method for treating PTA wastewater in this example is the same as that in Example 4, except that step (4) of the preparation method of the adsorption resin is different.

[0055] In this example, step (4) is specifically: adding the adsorption resin obtained in step (3) into N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine, 1,3-dimercaptopropane, and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 60°C for 8 h, and then filtering and washing to obtain the product.

[0056] Among them, the concentration of the adsorption resin in the N,N-dimethylformamide is 6 mg / ml; the mass ratio of the adsorption resin, 1,4-dimercapto-phthalazine, and azodiisobutyronitrile is 1:1.5:0.02. The mass ratio of 1,3-dimercaptopropane to 1,4-dimercapto-phthalazine is 0.05:1.

[0057] Comparative Example 1

[0058] The treatment method of PTA wastewater in this comparative example uses the same raw materials and the same amounts of each raw material as those in Example 4, with the only difference being that it does not include step (4).

[0059] Comparative Example 2

[0060] The treatment method of PTA wastewater in this comparative example uses the same raw materials and the same amounts of each raw material as those in Example 4, with the only difference being that in step (4), 1,4-dimercapto-phthalazine is replaced by 1,3-dimercaptopropane.

[0061] Comparative Example 3

[0062] The treatment method of PTA wastewater in this comparative example uses the same raw materials and the same amounts of each raw material as those in Example 7, with the only difference being that in step (4), the mass ratio of 1,3-dimercaptopropane to 1,4-dimercapto-phthalazine is 0.5:1.

[0063] Comparative Example 4

[0064] The treatment method of PTA wastewater in this comparative example uses the same raw materials and the same amounts of each raw material as those in Example 4, with the only difference being that 3-methyl-5-vinylpyridine is not added in step (1).

[0065] Comparative Example 5

[0066] The treatment method of PTA wastewater in this comparative example uses the same raw materials and the same amounts of each raw material as those in Example 4, with the only difference being that 3-methyl-5-vinylpyridine in step (1) is replaced by 3-vinylpyridine.

[0067] Effect Experimental Example

[0068] To verify the technical effects of the treatment method of PTA wastewater described in the present invention, the following tests were carried out: Take the PTA wastewater to be treated, measure its pH value to be 6, the bromide ion concentration to be 628 mg / L, and benzoic acid to be 367 mg / L. Prepare simulated PTA wastewater with sodium bromide and benzoic acid, adjust its pH value to 6, the bromide ion concentration to be 628 mg / L, and benzoic acid to be 367 mg / L. Respectively use the treatment methods of PTA wastewater prepared in Examples 1-7 and Comparative Examples 1-5 to treat the PTA wastewater to be treated and the simulated PTA wastewater, measure the concentrations of bromide ions and benzoic acid in the effluent after dynamic adsorption, and calculate the bromide ion removal rate and benzoic acid removal rate.

[0069] After the experiment, the results are as follows:

[0070] Respectively use the adsorption resins in Examples 1-7 and Comparative Examples 1-5 to adsorb the PTA wastewater to be treated and the simulated PTA wastewater, measure the adsorption capacity when the adsorption resin reaches saturation for bromide ions, denoted as the initial adsorption capacity Q1, then desorb the adsorption resin under the same conditions, repeat the above adsorption-desorption process until the number of desorption times reaches 10 times. When performing the 11th adsorption, measure the adsorption capacity when the adsorption resin reaches saturation for bromide ions, denoted as the final adsorption capacity Q2. Calculate the adsorption capacity decline rate R according to the following formula: R = (Q1 - Q2) / Q1; After the experiment, the results are as follows:

[0071] According to the above results, it can be seen that the treatment method of PTA wastewater described in the present invention can effectively remove aromatic organic acids represented by benzoic acid and bromide ions, effectively prevent damage to the reverse osmosis membrane in the subsequent process, and the adsorption material has a long service life.

[0072] According to the results of Examples 1-3, 4-6, and Comparative Example 1, compared with the adsorption resin without active terminal capping (Examples 1-3, Comparative Example 1), the adsorption resin obtained by capping with 1,4-dimercaptophthalazine through the "thiol-ene" reaction (Examples 4-6) can achieve better adsorption effects within the specified adsorption time, and can reach higher removal rates of bromide ions and benzoic acid in the treatment of the to-be-treated PTA wastewater and simulated PTA wastewater. Moreover, it has a higher adsorption capacity, and the difference in the adsorption amount decline rate is smaller when treating the to-be-treated PTA wastewater and simulated PTA wastewater. In Examples 1-3 and Comparative Example 1, when treating the simulated PTA wastewater with fewer interfering substances and lower salt content, a relatively smaller adsorption amount decline rate can be achieved. However, when treating the to-be-treated PTA wastewater with more interfering substances and higher salt content, the adsorption amount decline rate increases rapidly. This indicates that the adsorption resin without active terminal capping has a faster performance decline rate in PTA wastewater with high salt content and many interfering substances, and has a shorter service life when actually used to treat PTA wastewater.

[0073] According to the results of Examples 4-7 and Comparative Examples 2 and 3, compared with the adsorption resin obtained by only capping with 1,4-dimercaptophthalazine through the "thiol-ene" reaction (Examples 4-6), the adsorption resin obtained by capping with both 1,4-dimercaptophthalazine and 1,3-dimercaptopropane through the "thiol-ene" reaction (Examples 7, Comparative Example 3) has higher removal rates of bromide ions and benzoic acid and a lower adsorption amount decline rate. However, when the ratio of 1,3-dimercaptopropane to 1,4-dimercaptophthalazine is too large, the adsorption capacity of bromide ions decreases to a certain extent.

[0074] Compared with the adsorption resin obtained by only capping with 1,3-dimercaptopropane through the "thiol-ene" reaction (Comparative Example 2), the adsorption resin obtained by only capping with 1,4-dimercaptophthalazine through the "thiol-ene" reaction (Example 4) has little difference in the removal rates of bromide ions and benzoic acid in the simulated PTA wastewater. However, when treating the to-be-treated PTA wastewater with more interfering substances and higher salt content, the removal rates of bromide ions and benzoic acid decrease significantly. At the same time, compared with the adsorption resin without active terminal capping (Examples 1-3, Comparative Example 1), the difference in the adsorption amount decline rate of the to-be-treated PTA wastewater and simulated PTA wastewater in Comparative Example 2 is not large. This shows that although 1,3-dimercaptopropane can improve the tolerance of the adsorption resin in a high-salt environment, its adsorption selectivity for bromide ions is not good.

[0075] According to the results of Example 4 and Comparative Examples 4 and 5, the addition of the 3-methyl-5-vinylpyridine can significantly improve the various properties of the adsorption resin. This may be because it is difficult to form a sufficient and stable combination between the zeolite and the polymer monomer, resulting in a significant decrease in various properties as it is difficult to form a uniform and stable adsorption resin. For the 3-vinylpyridine in Comparative Example 5, although it can promote the polymerization reaction of the polymer monomer on the surface of the zeolite, its performance is still not ideal compared to Example 4 using the 3-methyl-5-vinylpyridine. This may be because the presence of the methyl group in the 3-methyl-5-vinylpyridine plays a role in regulating the surface properties of the zeolite, thereby affecting the interaction with the polymer monomer.

[0076] As is known to those skilled in the art, the present invention can be implemented by other embodiments without departing from its spiritual essence or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A method for treating PTA wastewater, characterized in that, It includes the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment and membrane separation treatment, then performing adsorption treatment with an adsorption resin, and then performing ultrafiltration and reverse osmosis treatment; Among them, the adsorption resin is composed of zeolite and polymer and is obtained by the following method: (1) Mix zeolite, styrene, divinylbenzene, initiator, pore-forming agent, and 3-methyl-5-vinylpyridine evenly to obtain an oil phase; (2) Mix water and dispersant evenly to obtain an aqueous phase; (3) Mix the oil phase in step (1) with the aqueous phase in step (2) evenly, stir, and then carry out a polymerization reaction to obtain an adsorption resin.

2. The treatment method of PTA wastewater according to claim 1, characterized in that, In step (1), the initiator is azobisisobutyronitrile; the pore-forming agent is one of toluene and xylene; the dispersant is one of hydroxyethyl cellulose, hydroxymethyl cellulose, and polyvinyl alcohol.

3. The treatment method of PTA wastewater according to claim 1, wherein, In step (1), the mass ratio of zeolite, styrene, divinylbenzene, initiator, and pore-forming agent is 1:(2 - 8):(0.5 - 2):(0.08 - 0.20):(1.8 - 3.6); Optionally, in step (2), in the aqueous phase, the mass fraction of the dispersant is 0.3 - 0.8 wt%; Optionally, in step (3), the volume ratio of the oil phase to the aqueous phase is 1:(5 - 8).

4. The treatment method of PTA wastewater according to claim 1, wherein In step (1), the mass ratio of zeolite to 3-methyl-5-vinylpyridine is 1:(0.2 - 1.0).

5. The treatment method of PTA wastewater according to claim 1, characterized in that, Step (1) specifically includes the following steps: first mix zeolite, 3-methyl-5-vinylpyridine, and pore-forming agent evenly, stir at 15 - 35 °C for 1 - 3 h, and then add styrene, divinylbenzene, and initiator thereto, and mix evenly at 15 - 35 °C to obtain an oil phase.

6. The treatment method of PTA wastewater according to claim 1, wherein Step (3) specifically includes the following steps: at 15 - 35 °C, add the oil phase to the aqueous phase, mix evenly, then raise the temperature to 70 - 100 °C at a rate of 1 - 3 °C / min, stir and react for 8 - 12 h, and obtain the adsorption resin after filtration, washing, and drying.

7. The treatment method of PTA wastewater according to claim 1, wherein The adsorption treatment is to install the adsorption resin on a resin bed for dynamic adsorption at a flow rate of 1 - 4 BV / h for 1 - 4 h.

8. The treatment method of PTA wastewater according to claim 1, characterized in that, The biodegradation treatment is carried out in a bioreactor for 24 - 96 h.

9. The treatment method of PTA wastewater according to claim 1, characterized in that, The membrane separation treatment is carried out using a microfiltration membrane with a pore size of 0.1 - 1 μm.

10. The treatment method of PTA wastewater according to claim 1, characterized in that, The ultrafiltration and reverse osmosis treatment are carried out using an ultrafiltration membrane with a pore size of 0.01 μm and a reverse osmosis membrane with a pore size of 0.5 - 10 nm.

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