A method for treating PTA wastewater

Abstract

The present invention provides a method for treating PTA wastewater, comprising the steps of: subjecting the treated PTA wastewater to biodegradation treatment and membrane separation treatment, then subjecting the treated PTA wastewater to adsorption treatment using an adsorption resin, and then subjecting the treated PTA wastewater to ultrafiltration and reverse osmosis treatment; wherein the adsorption resin is a composite of zeolite and a polymer, and is obtained by the following method: uniformly mixing zeolite, styrene, divinylbenzene, an initiator, a porogen, and 3-methyl-5-vinylpyridine to obtain an oil phase; uniformly mixing water and a dispersant to obtain an aqueous phase; uniformly mixing the oil phase and the aqueous phase, stirring, and then performing a polymerization reaction to obtain the adsorption resin. The method for treating PTA wastewater of the present invention combines physical processes with biochemical processes to effectively remove pollutants such as bromide ions and meet wastewater reuse requirements.

Description

Technical Field

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

[0002] Purified terephthalic acid (PTA), also known as pure terephthalic acid (PTA), is an organic compound typically present as white crystals or powder. Industrially, PTA is primarily produced through the liquid-phase oxidation of p-xylene to produce crude terephthalic acid, which is then refined through hydrogenation, crystallization, separation, and drying. PTA is an important chemical intermediate primarily used in the production of polyester fibers, polyester bottles, and certain engineering plastics. It is also a key raw material for intermediates such as dyes and pharmaceuticals.

[0003] The PTA production process generates a significant amount of process wastewater, primarily consisting of a mixture of reverse osmosis concentrate from the PTA wastewater station, desalination plant drainage, and boiler island desulfurization wastewater. This wastewater exhibits significant variability in both quality and quantity, with complex composition, high salinity, acidic properties, and a high COD content, making it a difficult-to-biodegrade chemical wastewater. The wastewater contains significant amounts of aromatic organic acids and inorganic ions, including p-carboxybenzaldehyde, benzoic acid, p-toluic acid, isophthalic acid, trimellitic acid, phthalic acid, and terephthalic acid. The inorganic ions primarily include cobalt, manganese, iron, calcium, magnesium, and bromine ions.

[0004] At present, physical adsorption is one of the key treatment steps for the deep treatment of purified terephthalic acid refining wastewater, which can remove most aromatic organic acids and inorganic ions. However, it faces the following problems:

[0005] The salt content in purified terephthalic acid refining wastewater is high. The molecular structure of the adsorption material is easily destroyed under high salt content, and its service life is usually short. In addition, when the adsorption material is used to remove bromide ions, the bromide ion treatment effect is poor. In the subsequent membrane treatment process, bromide ions will accelerate the aging and contamination of the reverse osmosis membrane, causing the performance of the reverse osmosis membrane to decline rapidly, and even the bromide ion content in the treated water to exceed the standard. Summary of the Invention

[0006] The object of the present invention is to provide a method for treating PTA wastewater to solve the problems in the prior art of treating PTA wastewater that the adsorption step is difficult to effectively remove bromide ions and the service life of the adsorption material is short.

[0007] The present invention provides the following technical solutions:

[0008] A method for treating PTA wastewater comprises the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment, membrane separation treatment, adsorption treatment by adsorption resin, and ultrafiltration and reverse osmosis treatment;

[0009] The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method:

[0010] (1) Zeolite, styrene, divinylbenzene, initiator, porogen, and 3-methyl-5-vinylpyridine are uniformly mixed to obtain an oil phase;

[0011] (2) Mix water and dispersant evenly to obtain an aqueous phase;

[0012] (3) The oil phase in step (1) and the water phase in step (2) are mixed evenly, stirred, and then subjected to polymerization reaction to obtain an adsorption resin.

[0013] Preferably, in step (1), the initiator is azobisisobutyronitrile; the porogen is one of toluene and xylene; and the dispersant is one of hydroxyethyl cellulose, hydroxymethyl cellulose, and polyvinyl alcohol.

[0014] Preferably, in step (1), the mass ratio of the zeolite, styrene, divinylbenzene, initiator, and porogen is 1: (2-8): (0.5-2): (0.08-0.20): (1.8-3.6);

[0015] Optionally, in step (2), the mass fraction of the dispersant in the aqueous phase is 0.3-0.8 wt %;

[0016] Optionally, in step (3), the volume ratio of the oil phase to the water phase is 1:(5-8).

[0017] Preferably, in step (1), the mass ratio of the zeolite to the 3-methyl-5-vinylpyridine is 1:(0.2-1.0).

[0018] Preferably, step (1) specifically comprises the following steps: firstly, zeolite, 3-methyl-5-vinylpyridine and porogen are uniformly mixed, and stirred at 15-35°C for 1-3h, and then styrene, divinylbenzene and initiator are added thereto, and mixed at 15-35°C to obtain an oil phase.

[0019] Preferably, step (3) specifically comprises the following steps: adding the oil phase to the water phase at 15-35°C, mixing evenly, then heating to 70-100°C at a rate of 1-3°C / min, stirring and reacting for 8-12h, filtering, washing, and drying to obtain an adsorption resin.

[0020] Preferably, the preparation method of the adsorption resin further comprises the following steps:

[0021] The adsorption resin obtained in step (3) is added to N,N-dimethylformamide, and then 1,4-dimercaptophthalazine and azobisisobutyronitrile are added thereto, mixed evenly, stirred and reacted at 50-70°C for 6-8h, filtered and washed to obtain the product.

[0022] 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).

[0023] Preferably, the preparation method of the adsorption resin further comprises the step of adding 1,3-dimercaptopropane; the mass ratio of the 1,3-dimercaptopropane to 1,4-dimercaptophthalazine is (0.03-0.08):1.

[0024] 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 hours.

[0025] Preferably, the biodegradation treatment uses a bioreactor for 24-96 hours.

[0026] Preferably, the membrane separation treatment is performed using a microfiltration membrane with a pore size of 0.1-1 μm.

[0027] Preferably, the ultrafiltration and reverse osmosis treatments are performed 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.

[0028] The above solution of the present invention includes at least the following beneficial effects:

[0029] (1) The method for treating PTA wastewater of the present invention comprises the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment and membrane separation treatment, and then subjecting the wastewater to adsorption treatment by an adsorption resin, and then subjecting the wastewater to ultrafiltration and reverse osmosis treatment; wherein the adsorption resin is a composite of zeolite and polymer, and is obtained by the following method: uniformly mixing zeolite, styrene, divinylbenzene, an initiator, a porogen, and 3-methyl-5-vinylpyridine to obtain an oil phase; uniformly mixing water and a dispersant to obtain an aqueous phase; uniformly mixing the oil phase and the aqueous phase, stirring, and then subjecting the mixture to a polymerization reaction to obtain an adsorption resin. The method for treating PTA wastewater of the present invention combines physical processes with biochemical processes, and can effectively remove pollutants such as bromide ions, thereby meeting the requirements for wastewater reuse. The biodegradation process can remove most suspended matter and organic matter in a high-salinity environment, thereby reducing the possibility of fouling and clogging in subsequent membrane separation treatment due to excessive suspended matter. The adsorption treatment can selectively adsorb bromide ions from the wastewater through the adsorption resin. After the bromide ions are removed, the damage of the bromide ions to the membranes used in the subsequent ultrafiltration and reverse osmosis processes can be greatly reduced. After the ultrafiltration and reverse osmosis treatment, the wastewater is ensured to reach a recyclable water quality, thereby realizing the recycling of the wastewater.

[0030] (2) The method for treating PTA wastewater of the present invention comprises the following steps: the adsorption resin is subjected to a polymerization reaction after mixing an oil phase formed by zeolite, styrene, divinylbenzene, an initiator, and a porogen with an aqueous phase, thereby obtaining a resin having good selectivity for bromide ions, a uniformly distributed macroporous structure, and a large specific surface area. In particular, the oil phase also includes 3-methyl-5-vinylpyridine. The pyridine group of the 3-methyl-5-vinylpyridine is alkaline and can combine with groups such as hydroxyl groups (-OH) on the surface of the zeolite when in contact with the zeolite, thereby introducing the pyridine group into the surface of the zeolite, thereby modifying the zeolite so that the surface of the zeolite has an active center that can initiate styrene polymerization. When styrene and divinylbenzene undergo a polymerization reaction under the action of the initiator, they interact with the surface of the zeolite to form a cross-linked structure. Because the 3-methyl-5-vinylpyridine participates in the polymerization reaction, the zeolite and polymer are more tightly bonded together, enhancing the resulting adsorption resin's resistance to swelling and dissolution under various environmental conditions. This improves the resin's chemical and mechanical stability, while also significantly increasing its adsorption selectivity and capacity for bromide ions. This allows for high adsorption efficiency, stable physical and chemical properties, and minimal impact from inorganic salts and other substances.

[0031] (3) The method for treating PTA wastewater of the present invention, the preparation method of the adsorption resin further comprises the following steps: adding the adsorption resin obtained in step (3) to N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 50-70°C for 6-8h, filtering and washing to obtain the adsorption resin. The adsorption resin contains a certain amount of unreacted alkenyl active ends, which can react with the thiol groups of 1,4-dimercaptophthalazine to achieve end-capping, making the polymer network of the resin more stable and enhancing its ability to resist salt ion corrosion and chemical degradation. At the same time, the thiol group and phthalazine ring with stable spatial structure are introduced. The presence of the thiol group can improve the adsorption selectivity of bromide ions, and the spatial conformation formed by the thiol group and the phthalazine ring is conducive to the specific adsorption of bromide ions and reduces the competitive adsorption of other ions. The phthalazine ring contains nitrogen atoms, has a large electronegativity, and has a conjugated system, which can adjust the charge distribution on the surface of the adsorption resin, reduce the damage of salt ions to the structure and functional groups of the adsorption resin, and thus improve the stability of the adsorption resin in high-salt water. DETAILED DESCRIPTION

[0032] In the examples of the present invention, if specific conditions are not specified, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Reagents or instruments used without specifying the manufacturer are all commercially available conventional products. Raw materials of different manufacturers and types do not affect the implementation of the technical solutions of the present invention and the achievement of the technical effects.

[0033] Example 1

[0034] The method for treating PTA wastewater of the present embodiment comprises the following steps:

[0035] The PTA wastewater to be treated is subjected to biodegradation treatment, reacted in a bioreactor for 24 hours, and then subjected to membrane separation treatment using a microfiltration membrane with a pore size of 0.1 μm. The adsorption resin is then installed on a resin bed for dynamic adsorption at a flow rate of 3 BV / h for 1 hour. The ultrafiltration membrane with a pore size of 0.01 μm is then used for ultrafiltration, and the reverse osmosis membrane with a pore size of 0.5 nm is used for reverse osmosis treatment.

[0036] The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method:

[0037] (1) First, zeolite, 3-methyl-5-vinylpyridine, and porogen were mixed evenly and stirred at 15°C for 2 h. Then, styrene, divinylbenzene, and initiator were added thereto and mixed evenly at 15°C to obtain an oil phase;

[0038] Among them, the initiator is azobisisobutyronitrile; the porogen is xylene; the mass ratio of the zeolite, styrene, divinylbenzene, initiator, and porogen is 1:5:0.5:0.20:1.8; and the mass ratio of the zeolite to the 3-methyl-5-vinylpyridine is 1:0.6.

[0039] (2) Mix water and dispersant evenly to obtain an aqueous phase;

[0040] The dispersant is hydroxyethyl cellulose, and the mass fraction of the dispersant in the aqueous phase is 0.3 wt%.

[0041] (3) Add the oil phase to the water phase at 15°C, mix well, then heat to 100°C at a rate of 1°C / min, stir and react for 8 hours, filter, wash and dry to obtain an adsorption resin.

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

[0043] Example 2

[0044] The method for treating PTA wastewater of the present embodiment comprises the following steps:

[0045] The PTA wastewater to be treated was subjected to biodegradation treatment, reacted in a bioreactor for 96 hours, and then subjected to membrane separation treatment using a microfiltration membrane with a pore size of 1 μm. The adsorption resin was then installed on a resin bed for dynamic adsorption at a flow rate of 4 BV / h for 4 hours. The ultrafiltration membrane with a pore size of 0.01 μm was then used for ultrafiltration, and the reverse osmosis membrane with a pore size of 10 nm was used for reverse osmosis treatment.

[0046] The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method:

[0047] (1) First, zeolite, 3-methyl-5-vinylpyridine, and porogen were mixed evenly and stirred at 35°C for 3 h. Then, styrene, divinylbenzene, and initiator were added thereto and mixed evenly at 35°C to obtain an oil phase;

[0048] Among them, the initiator is azobisisobutyronitrile; the porogen is xylene; the mass ratio of the zeolite, styrene, divinylbenzene, initiator, and porogen is 1:8:2:0.08:2.4; and the mass ratio of the zeolite to the 3-methyl-5-vinylpyridine is 1:0.2.

[0049] (2) Mix water and dispersant evenly to obtain an aqueous phase;

[0050] The dispersant is hydroxymethyl cellulose, and the mass fraction of the dispersant in the aqueous phase is 0.5 wt %.

[0051] (3) Add the oil phase to the water phase at 25°C, mix well, then heat to 85°C at a rate of 3°C / min, stir and react for 12 hours, filter, wash and dry to obtain an adsorption resin.

[0052] Wherein, the volume ratio of the oil phase to the water phase is 1:6.

[0053] Example 3

[0054] The method for treating PTA wastewater of the present embodiment comprises the following steps:

[0055] The PTA wastewater to be treated is subjected to biodegradation treatment, reacted in a bioreactor for 60 hours, and then subjected to membrane separation treatment using a microfiltration membrane with a pore size of 0.5 μm. The adsorption resin is then installed on a resin bed for dynamic adsorption at a flow rate of 1 BV / h for 3 hours. The ultrafiltration membrane with a pore size of 0.01 μm is then used for ultrafiltration, and the reverse osmosis membrane with a pore size of 5 nm is used for reverse osmosis treatment.

[0056] The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method:

[0057] (1) First, zeolite, 3-methyl-5-vinylpyridine, and porogen were mixed evenly and stirred at 25°C for 1 hour. Then, styrene, divinylbenzene, and initiator were added thereto and mixed evenly at 25°C to obtain an oil phase.

[0058] Among them, the initiator is azobisisobutyronitrile; the porogen is toluene; the mass ratio of the zeolite, styrene, divinylbenzene, initiator, and porogen is 1:2:1.5:0.1:3.6; and the mass ratio of the zeolite to the 3-methyl-5-vinylpyridine is 1:1.

[0059] (2) Mix water and dispersant evenly to obtain an aqueous phase;

[0060] The dispersant is polyvinyl alcohol, and the mass fraction of the dispersant in the aqueous phase is 0.8 wt%.

[0061] (3) Add the oil phase to the water phase at 35°C, mix well, then heat to 70°C at a rate of 2°C / min, stir and react for 10 hours, filter, wash and dry to obtain an adsorption resin.

[0062] Wherein, the volume ratio of the oil phase to the water phase is 1:5.

[0063] Example 4

[0064] The method for treating PTA wastewater of the present embodiment comprises the following steps:

[0065] The PTA wastewater to be treated was subjected to biodegradation treatment, reacted in a bioreactor for 65 hours, and then subjected to membrane separation treatment using a microfiltration membrane with a pore size of 0.6 μm. The adsorption resin was then installed on a resin bed for dynamic adsorption at a flow rate of 4 BV / h for 2 hours. The ultrafiltration membrane with a pore size of 0.01 μm was then used for ultrafiltration, and the reverse osmosis membrane with a pore size of 8 nm was used for reverse osmosis treatment.

[0066] The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method:

[0067] (1) First, zeolite, 3-methyl-5-vinylpyridine, and porogen were mixed evenly and stirred at 25°C for 3 h. Then, styrene, divinylbenzene, and initiator were added thereto and mixed evenly at 25°C to obtain an oil phase;

[0068] Among them, the initiator is azobisisobutyronitrile; the porogen is toluene; the mass ratio of the zeolite, styrene, divinylbenzene, initiator, and porogen is 1:6:1.5:0.12:2.5; and the mass ratio of the zeolite to the 3-methyl-5-vinylpyridine is 1:0.6.

[0069] (2) Mix water and dispersant evenly to obtain an aqueous phase;

[0070] The dispersant is polyvinyl alcohol, and the mass fraction of the dispersant in the aqueous phase is 0.8 wt%.

[0071] (3) Add the oil phase to the water phase at 25°C, mix well, then heat to 90°C at a rate of 3°C / min, stir and react for 10 hours, filter, wash and dry to obtain an adsorption resin.

[0072] Wherein, the volume ratio of the oil phase to the water phase is 1:8.

[0073] (4) The adsorption resin obtained in step (3) is added to N,N-dimethylformamide, and then 1,4-dimercaptophthalazine and azobisisobutyronitrile are added thereto, mixed evenly, stirred and reacted at 60°C for 8h, filtered and washed to obtain the product.

[0074] The concentration of the adsorption resin in the 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.

[0075] Example 5

[0076] The method for treating PTA wastewater in this embodiment is the same as that in Example 4, except that step (4) of the method for preparing the adsorption resin is different.

[0077] In this embodiment, step (4) is specifically as follows: adding the adsorption resin obtained in step (3) to N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 60°C for 8h, filtering and washing to obtain the product.

[0078] The concentration of the adsorption resin in the 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.

[0079] Example 6

[0080] The method for treating PTA wastewater in this embodiment is the same as that in Example 4, except that step (4) of the method for preparing the adsorption resin is different.

[0081] In this embodiment, step (4) is specifically as follows: adding the adsorption resin obtained in step (3) to N,N-dimethylformamide, then adding 1,4-dimercaptophthalazine and azobisisobutyronitrile thereto, mixing evenly, stirring and reacting at 60°C for 8h, filtering and washing to obtain the product.

[0082] The concentration of the adsorption resin in the 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.

[0083] Example 7

[0084] The method for treating PTA wastewater in this embodiment is the same as that in Example 4, except that step (4) of the method for preparing the adsorption resin is different.

[0085] In this embodiment, step (4) is specifically as follows: adding the adsorption resin obtained in step (3) to N,N-dimethylformamide, and then adding 1,4-dimercaptophthalazine, 1,3-dimercaptopropane, and azobisisobutyronitrile thereto, mixing them evenly, stirring and reacting at 60°C for 8h, filtering, and washing to obtain the product.

[0086] The concentration of the adsorption resin in the 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; and the mass ratio of the 1,3-dimercaptopropane to the 1,4-dimercaptophthalazine is 0.05:1.

[0087] Comparative Example 1

[0088] The method for treating PTA wastewater in this comparative example uses the same raw materials and the same amounts of raw materials as those used in Example 4, with the only difference being that step (4) is not included.

[0089] Comparative Example 2

[0090] The method for treating PTA wastewater in this comparative example uses the same raw materials and the same amounts of raw materials as those used in Example 4, with the only difference being that in step (4), the 1,4-dimercaptophthalazine is replaced by 1,3-dimercaptopropane.

[0091] Comparative Example 3

[0092] The method for treating PTA wastewater in this comparative example uses the same raw materials and the same amounts of raw materials as those used in Example 7, with the only difference being that in step (4), the mass ratio of the 1,3-dimercaptopropane to the 1,4-dimercaptophthalazine is 0.5:1.

[0093] Comparative Example 4

[0094] The method for treating PTA wastewater in this comparative example uses the same raw materials and the same amounts of raw materials as those used in Example 4, with the only difference being that 3-methyl-5-vinylpyridine is not added in step (1).

[0095] Comparative Example 5

[0096] The method for treating PTA wastewater in this comparative example uses the same raw materials and the same amounts of raw materials as those used in Example 4, with the only difference being that 3-methyl-5-vinylpyridine in step (1) is replaced by 3-vinylpyridine.

[0097] Effect Experiment Example

[0098] In order to verify the technical effect of the method for treating PTA wastewater of the present invention, the following experiments were conducted:

[0099] The pH of the untreated PTA wastewater was measured to be 6, with a bromide ion concentration of 628 mg / L and a benzoic acid concentration of 367 mg / L. Simulated PTA wastewater was prepared using sodium bromide and benzoic acid, and its pH was adjusted to 6, a bromide ion concentration of 628 mg / L, and a benzoic acid concentration of 367 mg / L. The untreated PTA wastewater and the simulated PTA wastewater were treated using the treatment methods prepared in Examples 1-7 and Comparative Examples 1-5, respectively. The bromide ion and benzoic acid concentrations of the effluent after dynamic adsorption were measured, and the bromide ion removal rate and benzoic acid removal rate were calculated.

[0100] After testing, the results are as follows:

[0101]

[0102] The adsorption resins described in Examples 1-7 and Comparative Examples 1-5 were used to adsorb the treated PTA wastewater and the simulated PTA wastewater, respectively. The adsorption capacity of the adsorption resin when it reached saturation with bromide ions was measured, which was recorded as the initial adsorption capacity Q1. The adsorption resin was then desorbed under the same conditions, and the adsorption-desorption process was repeated until the desorption number reached 10 times. During the 11th adsorption, the adsorption capacity of the adsorption resin when it reached saturation with bromide ions was measured, which was recorded as the final adsorption capacity Q2. The adsorption capacity decrease rate R was calculated according to the following formula:

[0103] R=(Q1-Q2) / Q1;

[0104] After testing, the results are as follows:

[0105]

[0106] According to the above results, 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 them from damaging the reverse osmosis membrane in subsequent processes, and the service life of the adsorption material is long.

[0107] The results of Examples 1-3, 4-6, and Comparative Example 1 demonstrate that, compared to the adsorption resins without active end-capping (Examples 1-3 and Comparative Example 1), the adsorption resins obtained by capping the resins with 1,4-dimercaptophthalazine through a "mercapto-olefin" reaction (Examples 4-6) achieve better adsorption within the specified adsorption time. They achieve higher bromide ion and benzoic acid removal rates in both the treated PTA wastewater and simulated PTA wastewater. Furthermore, they exhibit higher adsorption capacity, with minimal difference in the rate of adsorption reduction when treating both the treated PTA wastewater and the simulated PTA wastewater. In Examples 1-3 and Comparative Example 1, when treating simulated PTA wastewater with few interfering substances and low salt content, a relatively smaller adsorption capacity decrease rate can be achieved. However, when treating untreated PTA wastewater with many interfering substances and high salt content, the adsorption capacity decrease rate increases rapidly. This shows that the adsorption resin without active end-capping has a faster performance decline rate in PTA wastewater with high salt content and many interfering substances, and its service life is short when it is actually used to treat PTA wastewater.

[0108] The results of Examples 4-7 and Comparative Examples 2 and 3 show that compared to the adsorption resin obtained by capping the adsorption resin using only 1,4-dimercaptophthalazine through a "mercapto-olefin" reaction (Examples 4-6), the adsorption resin obtained by capping the adsorption resin using both 1,4-dimercaptophthalazine and 1,3-dimercaptopropane through a "mercapto-olefin" reaction (Example 7 and Comparative Example 3) exhibited higher bromide ion and benzoic acid removal rates and lower rates of adsorption capacity loss. However, when the ratio of 1,3-dimercaptopropane to 1,4-dimercaptophthalazine was too high, the bromide ion adsorption capacity decreased to a certain extent.

[0109] Compared to the adsorption resin obtained by capping the mercapto-olefin reaction using only 1,3-dimercaptopropane (Comparative Example 2), the adsorption resin obtained by capping the mercapto-olefin reaction using only 1,4-dimercaptophthalazine (Example 4) showed similar bromide ion and benzoic acid removal rates for simulated PTA wastewater. However, the bromide ion and benzoic acid removal rates decreased significantly when treating untreated PTA wastewater with a high salt content and a high interfering substance content. Furthermore, compared to the adsorption resin without active end-capping (Examples 1-3 and Comparative Example 1), the reduction in adsorption capacity for both the untreated PTA wastewater and the simulated PTA wastewater in Comparative Example 2 was similar. This suggests that while 1,3-dimercaptopropane can improve the adsorption resin's tolerance to high-salt environments, its adsorption selectivity for bromide ions is poor.

[0110] The results of Example 4 and Comparative Examples 4 and 5 show that the addition of 3-methyl-5-vinylpyridine significantly improves various properties of the adsorption resin. This is likely due to the difficulty in achieving a sufficient and stable bond between the zeolite and the polymer monomer, making it difficult to form a uniform and stable adsorption resin, resulting in a significant decrease in various properties. While the 3-vinylpyridine in Comparative Example 5 promotes polymerization of the polymer monomer on the zeolite surface, its performance is still less than ideal compared to Example 4 using 3-methyl-5-vinylpyridine. This is likely due to the presence of the methyl group in the 3-methyl-5-vinylpyridine, which modulates the surface properties of the zeolite and, in turn, affects its interaction with the polymer monomer.

[0111] It is understood from common knowledge in the art that the present invention may be implemented by other embodiments that do not depart from its spirit or essential features. Therefore, the embodiments disclosed above are, in all respects, illustrative only and not exclusive. All modifications within the scope of the present invention or equivalent to the scope of the present invention are intended to be encompassed by the present invention.

Claims

1. A method for treating PTA wastewater, characterized in that: The method comprises the following steps: subjecting the PTA wastewater to be treated to biodegradation treatment, membrane separation treatment, adsorption treatment through adsorption resin, and then ultrafiltration and reverse osmosis treatment; The adsorption resin is a composite of zeolite and polymer, and is obtained by the following method: (1) Zeolite, styrene, divinylbenzene, initiator, porogen, and 3-methyl-5-vinylpyridine are uniformly mixed to obtain an oil phase; (2) Mix water and dispersant evenly to obtain an aqueous phase; (3) Add the oil phase in step (1) to the water phase in step (2) at 15-35°C, mix well, then heat to 70-100°C at a rate of 1-3°C / min, stir and react for 8-12 hours, filter, wash and dry to obtain an adsorption resin; (4) Add the adsorption resin obtained in step (3) to N,N-dimethylformamide, then add 1,4-dimercaptophthalazine and azobisisobutyronitrile, mix well, stir and react at 50-70°C for 6-8h, filter and wash to obtain; 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); The preparation method of the adsorption resin further includes the step of adding 1,3-dimercaptopropane; the mass ratio of the 1,3-dimercaptopropane to 1,4-dimercaptophthalazine is (0.03-0.08):

1.

2. The method for treating PTA wastewater according to claim 1, wherein In step (1), the initiator is azobisisobutyronitrile; the porogen is one of toluene and xylene; and the dispersant is one of hydroxyethyl cellulose, hydroxymethyl cellulose, and polyvinyl alcohol.

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

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

5. The method for treating PTA wastewater according to claim 1, wherein Step (1) specifically includes the following steps: firstly, zeolite, 3-methyl-5-vinylpyridine and porogen are uniformly mixed, and stirred at 15-35°C for 1-3h, and then styrene, divinylbenzene and initiator are added thereto, and mixed at 15-35°C to obtain an oil phase.

6. The method for treating 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 hours.

7. The method for treating PTA wastewater according to claim 1, wherein The biodegradation treatment adopts a bioreactor to react for 24-96 hours.

8. The method for treating PTA wastewater according to claim 1, wherein The membrane separation treatment is performed using a microfiltration membrane with a pore size of 0.1-1 μm.

9. The method for treating PTA wastewater according to claim 1, wherein The ultrafiltration and reverse osmosis treatments are performed 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.

Images