High-selectivity composite adsorption material for petrochemical wastewater treatment and preparation method of high-selectivity composite adsorption material

Abstract

The invention relates to the technical field of petrochemical wastewater purification treatment, in particular to a high-selectivity composite adsorption material for petrochemical wastewater treatment and a preparation method thereof, and the preparation method comprises the following steps: dispersing sodium bentonite in deionized water, adding an intercalator, and reacting to obtain pretreated bentonite; dispersing the pretreated bentonite in an ethanol aqueous solution, adding trithiol-s-triazine trisodium salt, and reacting to obtain sulfydryl modified bentonite; the sulfydryl modified bentonite is dispersed in ethyl alcohol, an amino silane coupling agent is dropwise added, and aminated bentonite is obtained through a reaction; the preparation method comprises the following steps: dispersing aminated bentonite into anhydrous tetrahydrofuran, and adding gamma-butyl selenolactone for reaction to obtain the composite adsorption material. According to the prepared composite material, through the synergistic effect of multiple adsorption mechanisms, the adsorption selectivity and bonding strength of metal ions in petrochemical wastewater are remarkably improved, and a technical support is provided for precise purification treatment of the petrochemical wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical wastewater purification and treatment, and in particular to a highly selective composite adsorption material for petrochemical wastewater treatment and a preparation method thereof. Background Art

[0002] Petrochemical wastewater has a complex composition and usually contains a variety of organic pollutants and heavy metal ions, posing a serious threat to the environment and human health. Traditional physical and chemical treatment methods often have problems such as low treatment efficiency, high cost, and secondary pollution. Adsorption has been widely used in the field of petrochemical wastewater treatment due to its advantages such as simple operation, high treatment efficiency, and relatively low cost. In recent years, various new adsorption materials such as activated carbon, biochar, and metal-organic framework materials have continued to emerge, but these materials still face technical bottlenecks in practical applications such as poor selectivity, limited adsorption capacity, and difficulty in regeneration. In particular, the heavy metal ions in petrochemical wastewater are of various types and have large concentration differences. Traditional adsorption materials often have similar adsorption capacities for different metal ions, making it difficult to achieve selective enrichment and efficient removal of specific highly toxic metal ions. There is an urgent need to develop functional materials with highly selective adsorption mechanisms.

[0003] Bentonite, as a natural clay mineral, has the characteristics of layered structure, large specific surface area, and strong ion exchange capacity, and is widely used in the field of wastewater treatment. In order to improve the adsorption performance of bentonite, researchers have developed a variety of modification methods. For example, CN201710343150.6 discloses a method for preparing a ternary composite modified bentonite material. The preparation method of the ternary composite modified bentonite material is as follows: first, the bentonite is acid-modified with a dilute acid solution with a concentration of 1-10wt% to obtain acid-modified bentonite; then, the acid-modified bentonite is organically modified with a quaternary ammonium salt. After the organic modification reaction is completed, polyhydroxyaluminum is added to the system for inorganic modification to obtain a ternary composite modified bentonite material. However, the existing bentonite modification technology still has obvious shortcomings: on the one hand, traditional acid modification can easily lead to the destruction of the bentonite structure and affect its stability; on the other hand, the existing modification methods mainly work through physical adsorption and simple ion exchange mechanisms, lack the ability to chemically recognize specific metal ions, and have low selectivity for target heavy metal ions. It is difficult to achieve accurate and efficient removal effects in complex petrochemical wastewater containing multiple metal ions. Summary of the Invention

[0004] In view of this, the present invention proposes a highly selective composite adsorption material for petrochemical wastewater treatment and a preparation method thereof, in order to solve the problem in the prior art that bentonite is difficult to achieve accurate and efficient removal in complex petrochemical wastewater.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment, comprising the following steps:

[0006] S1. Disperse sodium bentonite in deionized water, add an intercalant, and heat to 60-80° C. for 1-2 hours to obtain pretreated bentonite.

[0007] S2. Dispersing the pretreated bentonite in an ethanol aqueous solution, adding trithiodisulfide s-triazine trisodium salt, and stirring at 25-30° C. for 14-18 hours to obtain thiol-modified bentonite;

[0008] S3, dispersing the mercapto-modified bentonite in ethanol, ultrasonically dispersing, adding an aminosilane coupling agent dropwise, and reacting at 70-90° C. for 4-5 hours under nitrogen protection to obtain amino-modified bentonite;

[0009] S4. Disperse the amino bentonite in anhydrous tetrahydrofuran, add γ-butylselenolactone, and react at 40-50° C. for 1-2 hours under nitrogen protection to obtain the composite adsorption material.

[0010] On the basis of the above technical solution, preferably, in step S1, the mass ratio of sodium bentonite to intercalant is 1:0.45-0.55, and the intercalant is 1-hexadecyl-3-methylimidazolium bromide.

[0011] Specifically, in step S1, 1-hexadecyl-3-methylimidazolium bromide is used as an intercalation agent to modify bentonite through an ion exchange mechanism, increasing the interlayer structure of the bentonite. Simultaneously, the imidazole ring in the intercalation agent molecule, as an aromatic heterocyclic structure, can form a π-π stacking interaction with the triazine ring of the subsequent trimercapto-s-triazine trisodium salt to be loaded, further improving the loading rate and loading stability of the trimercapto-s-triazine trisodium salt. In step S2, the thiol group contained in the trimercapto-s-triazine trisodium salt has a strong affinity for metal ions such as mercury, lead, and cadmium, thereby improving the adsorption capacity for these metal ions. In step S3, an aminosilane coupling agent is grafted onto the bentonite surface to provide reactive sites for the subsequent introduction of γ-butylselenolactone molecules. Furthermore, the amino group itself has a certain metal ion complexing ability, forming a synergistic adsorption effect with the thiol group of the trimercapto-s-triazine trisodium salt. In step S4, γ-butylselenolide is a cyclic organic selenium compound that can undergo a ring-opening reaction with an amino group under mild conditions. The organic selenium group on the γ-butylselenolide molecule has a very strong affinity for certain specific heavy metal ions (such as mercury ions), forming a very stable metal-selenium coordination bond. More importantly, there is an obvious synergistic effect between the selenium group and the thiol group of trithiol-s-triazine trisodium salt: the two can form multidentate chelate complexes with the same metal ion, greatly enhancing the stability of the coordination bond. In addition, γ-butylselenolide also has certain antioxidant properties, which helps to maintain the chemical stability of the material during long-term use.

[0012] On the basis of the above technical solution, preferably, in step S2, the mass ratio of the pretreated bentonite to the trisodium salt of trimercapto-s-triazine is 1:0.08-0.15.

[0013] Based on the above technical solution, preferably, in step S3, the mass ratio of the mercapto-modified bentonite to the aminosilane coupling agent is 1:0.06-0.12.

[0014] On the basis of the above technical solution, preferably, the aminosilane coupling agent is (3-aminopropyl)trimethoxysilane or (3-aminopropyl)triethoxysilane.

[0015] On the basis of the above technical solution, preferably, in step S4, the mass ratio of the aminated bentonite to γ-butylselenolactone is 1:0.04-0.1.

[0016] Based on the above technical solution, preferably, in step S1, the preparation method of sodium bentonite includes:

[0017] S11, adding bentonite ore and sodium polyacrylate into water, stirring and then allowing to stand, filtering, centrifuging, and drying to obtain purified bentonite;

[0018] S12. The purified bentonite is dispersed in water, sodium carbonate is added, and the mixture is heated at 60-80° C. for 1-1.5 hours to obtain sodium bentonite.

[0019] Based on the above technical solution, preferably, in step S11, the amount of sodium polyacrylate added is 0.2-0.3% of the mass of the original bentonite; in step S12, the amount of sodium carbonate added is 3-5% of the mass of the purified bentonite.

[0020] Specifically, sodium polyacrylate, as an anionic polymer dispersant, prevents bentonite particles from agglomerating through the dual mechanisms of electrostatic repulsion and steric hindrance. Through the dispersing effect of sodium polyacrylate, the montmorillonite particles in the bentonite ore can be fully dispersed, avoiding the valuable minerals from settling with the coarse particles due to agglomeration, and significantly improving the recovery rate of fine-grained montmorillonite. Sodium carbonate undergoes ion exchange reaction with calcium and magnesium ions between bentonite layers to produce sodium-based bentonite. + After replacing divalent cations, the expansibility and ion exchange capacity of bentonite were significantly improved, and the interlayer structure was more conducive to subsequent intercalation modification.

[0021] The present invention also provides a highly selective composite adsorption material for petrochemical wastewater treatment, wherein the highly selective composite adsorption material is prepared by the preparation method according to any one of claims 1 to 8.

[0022] The present invention also provides a use of the highly selective composite adsorption material described above in the purification of petrochemical wastewater.

[0023] The highly selective composite adsorption material for petrochemical wastewater treatment and the preparation method thereof of the present invention have the following beneficial effects compared with the prior art:

[0024] (1) The present invention constructs a composite adsorption material with the synergistic effect of multiple functional groups through a four-step preparation process of intercalation pretreatment, thiol modification, amination and selenolactone modification. The material combines the layered porous structure of bentonite, the strong chelating ability of trimercapto-s-triazine, the complexing properties of amino groups and the specific binding characteristics of organic selenium groups to achieve highly selective adsorption of specific heavy metal ions in petrochemical wastewater. Compared with traditional single-functional adsorption materials, the composite material prepared by the present invention significantly improves the adsorption of metal ions (Hg 2+ , Pb 2+ and Cd 2+ )’s adsorption selectivity and binding strength provide technical support for the precise purification treatment of petrochemical wastewater.

[0025] (2) In the present invention, 1-hexadecyl-3-methylimidazolium bromide is used as an intercalating agent. Its long carbon chain structure effectively expands the interlayer distance, and the imidazole ring structure forms a stable bond with trithiolsammonium trisalicylate through π-π stacking, thereby improving the loading density and stability of the functional groups. Subsequently, sodium bentonite is grafted and modified with trithiolsammonium trisalicylate, aminosilane coupling agent, and γ-butylselenolide. The three functional groups of thiol, amino, and organic selenium are arranged in an orderly manner in space. When heavy metal ions enter the adsorption site, they can simultaneously form a stable multi-dentate chelate ring with multiple coordinating atoms. The covalent bonding of the silane coupling agent and the electrostatic interaction of the intercalating agent jointly construct a multi-level molecular anchoring system, ensuring the long-term stable existence of each functional group in a complex water environment, avoiding the performance degradation caused by the loss of functional components, and achieving the organic unity of structural stability and adsorption activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 paying any creative work.

[0027] Figure 1 The present invention is a flow chart of a method for preparing a highly selective composite adsorption material for treating petrochemical wastewater. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment, comprising the following steps:

[0031] (1) 100 g of bentonite ore and 0.25 g of sodium polyacrylate were added to 1000 ml of water, stirred for 1.5 h, and then allowed to stand for 30 min. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 min). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 4 g of sodium carbonate was added, and the mixture was heated at 70 ° C for 1-1.5 h. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 min), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0032] (2) Disperse 100 g of sodium bentonite in 1000 ml of deionized water and ultrasonically disperse it for 15 min to fully disperse it. Dissolve 50 g of 1-hexadecyl-3-methylimidazolium bromide in 100 ml of warm water to prepare a solution, which is then slowly added dropwise to the bentonite dispersion. The temperature is raised to 70°C and the reaction is continued for 1.5 h. After the reaction is completed, the solution is centrifuged, washed 2-3 times with 60°C hot water, and dried in an oven at 80°C to obtain pretreated bentonite.

[0033] (3) 100 g of pretreated bentonite was dispersed in 1000 ml of ethanol aqueous solution (the volume of ethanol and water was 3:1), ultrasonically dispersed for 20 min, 11 g of trithiodimethoxy-s-triazine trisodium salt was dissolved in 20 ml of water, and slowly added dropwise to the bentonite dispersion under stirring at room temperature, and stirred at 27 ° C for 16 h. After the reaction was completed, the mixture was centrifuged, washed with ethanol 2-3 times, and dried in an oven at 60 ° C to obtain thiol-modified bentonite;

[0034] (4) 100 g of mercapto-modified bentonite was dispersed in 1000 ml of ethanol, and dry nitrogen was introduced to remove moisture. The mixture was ultrasonically dispersed for 15 min, and 9 g of aminosilane coupling agent was added dropwise. The mixture was reacted at 80 ° C for 4.5 h under nitrogen protection. After the reaction, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous ethanol, and then washed once with acetone. The mixture was dried in a vacuum oven at 60 ° C to obtain amino-modified bentonite.

[0035] (5) 100 g of amino bentonite was dispersed in 1000 ml of anhydrous tetrahydrofuran, and dry nitrogen was introduced to remove water. The mixture was ultrasonically dispersed for 10 min, and 7 g of γ-butylselenolide was added. The mixture was reacted at 45 ° C for 1.5 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous tetrahydrofuran, and once with anhydrous ethanol. The mixture was dried in a vacuum oven at 50 ° C, and ground through a 100 mesh sieve to obtain a composite adsorption material.

[0036] Example 2

[0037] This embodiment provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment, comprising the following steps:

[0038] (1) 100 g of bentonite ore and 0.2 g of sodium polyacrylate were added to 1000 ml of water, stirred for 1 hour, and then allowed to stand for 30 minutes. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 minutes). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 3 g of sodium carbonate was added, and the mixture was heated at 60 ° C for 1.5 hours. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 minutes), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0039] (2) Disperse 100g of sodium bentonite in 1000ml of deionized water and disperse thoroughly by ultrasonic dispersion for 15min. Dissolve 45g of 1-hexadecyl-3-methylimidazolium bromide in 100ml of warm water to prepare a solution, then slowly add the solution dropwise to the bentonite dispersion and heat to 60°C for 2h. After the reaction, centrifuge, wash 2-3 times with 60°C hot water, and dry in an oven at 80°C to obtain pretreated bentonite.

[0040] (3) 100 g of pretreated bentonite was dispersed in 1000 ml of ethanol aqueous solution (the volume of ethanol and water was 3:1), ultrasonically dispersed for 20 min, 8 g of trithiodimethoxy-s-triazine trisodium salt was dissolved in 20 ml of water, and slowly added dropwise to the bentonite dispersion under stirring at room temperature, and stirred at 25 ° C for 18 h. After the reaction was completed, the mixture was centrifuged, washed with ethanol 2-3 times, and dried in an oven at 60 ° C to obtain thiol-modified bentonite;

[0041] (4) 100 g of mercapto-modified bentonite was dispersed in 1000 ml of ethanol, and dry nitrogen was introduced to remove moisture. The mixture was ultrasonically dispersed for 15 min, and 6 g of aminosilane coupling agent was added dropwise. The mixture was reacted at 70 ° C for 5 h under nitrogen protection. After the reaction, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous ethanol, and then washed once with acetone. The mixture was dried in a vacuum oven at 60 ° C to obtain amino-modified bentonite.

[0042] (5) 100 g of amino bentonite was dispersed in 1000 ml of anhydrous tetrahydrofuran, and dry nitrogen was introduced to remove water. Ultrasonic dispersion was performed for 10 min, and 4 g of γ-butylselenolide was added. The mixture was reacted at 40 °C for 2 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous tetrahydrofuran, and once with anhydrous ethanol. The mixture was dried in a vacuum oven at 50 °C and ground through a 100-mesh sieve to obtain a composite adsorbent material.

[0043] Example 3

[0044] This embodiment provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment, comprising the following steps:

[0045] (1) 100 g of bentonite ore and 0.3 g of sodium polyacrylate were added to 1000 ml of water, stirred for 2 h, and then allowed to stand for 30 min. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 min). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 5 g of sodium carbonate was added, and the mixture was heated at 80 ° C for 1 h. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 min), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0046] (2) Disperse 100g of sodium bentonite in 1000ml of deionized water and disperse thoroughly by ultrasonic dispersion for 15min. Dissolve 55g of 1-hexadecyl-3-methylimidazolium bromide in 100ml of warm water to prepare a solution, then slowly add the solution dropwise to the bentonite dispersion and heat to 80°C for 1h. After the reaction, centrifuge, wash 2-3 times with 60°C hot water, and dry in an oven at 80°C to obtain pretreated bentonite.

[0047] (3) 100 g of pretreated bentonite was dispersed in 1000 ml of ethanol aqueous solution (the volume of ethanol and water was 3:1), ultrasonically dispersed for 20 min, 15 g of trithiodimethoxy-s-triazine trisodium salt was dissolved in 20 ml of water, and slowly added dropwise to the bentonite dispersion under stirring at room temperature, and stirred at 30 ° C for 14 h. After the reaction was completed, the mixture was centrifuged, washed with ethanol 2-3 times, and dried in an oven at 60 ° C to obtain thiol-modified bentonite;

[0048] (4) 100 g of mercapto-modified bentonite was dispersed in 1000 ml of ethanol, and dry nitrogen was introduced to remove moisture. The mixture was ultrasonically dispersed for 15 min, and 12 g of aminosilane coupling agent was added dropwise. The mixture was reacted at 90 ° C for 4 h under nitrogen protection. After the reaction, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous ethanol, and then washed once with acetone. The mixture was dried in a vacuum oven at 60 ° C to obtain amino-modified bentonite.

[0049] (5) 100 g of amino bentonite was dispersed in 1000 ml of anhydrous tetrahydrofuran, and dry nitrogen was introduced to remove water. Ultrasonic dispersion was performed for 10 min, and 10 g of γ-butylselenolide was added. The mixture was reacted at 50 ° C for 1 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous tetrahydrofuran, and once with anhydrous ethanol. The mixture was dried in a vacuum oven at 50 ° C, and ground through a 100-mesh sieve to obtain a composite adsorption material.

[0050] Comparative Example 1

[0051] This comparative example provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment. The preparation method is the same as that of Example 1, except that the intercalant in step (2) is hexadecyl ammonium bromide, and the amount added is the same as that of Example 1.

[0052] Comparative Example 2

[0053] This comparative example provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment. The preparation method is the same as that of Example 1, except that the sodium bentonite is not introduced with trisodium trithiolstrazine. Specifically, the method is as follows:

[0054] (1) 100 g of bentonite ore and 0.25 g of sodium polyacrylate were added to 1000 ml of water, stirred for 1.5 h, and then allowed to stand for 30 min. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 min). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 4 g of sodium carbonate was added, and the mixture was heated at 70 ° C for 1-1.5 h. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 min), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0055] (2) Disperse 100 g of sodium bentonite in 1000 ml of deionized water and ultrasonically disperse it for 15 min to fully disperse it. Dissolve 50 g of 1-hexadecyl-3-methylimidazolium bromide in 100 ml of warm water to prepare a solution, which is then slowly added dropwise to the bentonite dispersion. The temperature is raised to 70°C and the reaction is continued for 1.5 h. After the reaction is completed, the solution is centrifuged, washed 2-3 times with 60°C hot water, and dried in an oven at 80°C to obtain pretreated bentonite.

[0056] (3) Disperse 100 g of pretreated bentonite in 1000 ml of ethanol, introduce dry nitrogen to remove moisture, ultrasonically disperse for 15 min, dropwise add 9 g of aminosilane coupling agent, react at 80 ° C for 4.5 h under nitrogen protection, cool to room temperature after the reaction, centrifuge, wash twice with anhydrous ethanol, then wash once with acetone, and dry in a vacuum oven at 60 ° C to obtain amino bentonite;

[0057] (4) 100 g of amino bentonite was dispersed in 1000 ml of anhydrous tetrahydrofuran, and dry nitrogen was introduced to remove water. Ultrasonic dispersion was performed for 10 min, and 7 g of γ-butylselenolide was added. The mixture was reacted at 45 ° C for 1.5 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, washed twice with anhydrous tetrahydrofuran, and once with anhydrous ethanol. The mixture was dried in a vacuum oven at 50 ° C, and ground through a 100-mesh sieve to obtain a composite adsorption material.

[0058] Comparative Example 3

[0059] This comparative example provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment. The preparation method is the same as that of Example 1, except that γ-butylselenolactone is not grafted. Specifically,

[0060] (1) 100 g of bentonite ore and 0.25 g of sodium polyacrylate were added to 1000 ml of water, stirred for 1.5 h, and then allowed to stand for 30 min. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 min). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 4 g of sodium carbonate was added, and the mixture was heated at 70 ° C for 1-1.5 h. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 min), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0061] (2) Disperse 100 g of sodium bentonite in 1000 ml of deionized water and ultrasonically disperse it for 15 min to fully disperse it. Dissolve 50 g of 1-hexadecyl-3-methylimidazolium bromide in 100 ml of warm water to prepare a solution, which is then slowly added dropwise to the bentonite dispersion. The temperature is raised to 70°C and the reaction is continued for 1.5 h. After the reaction is completed, the solution is centrifuged, washed 2-3 times with 60°C hot water, and dried in an oven at 80°C to obtain pretreated bentonite.

[0062] (3) 100 g of pretreated bentonite was dispersed in 1000 ml of ethanol aqueous solution (the volume of ethanol and water was 3:1), ultrasonically dispersed for 20 min, 11 g of trithiodimethoxy-s-triazine trisodium salt was dissolved in 20 ml of water, and slowly added dropwise to the bentonite dispersion under stirring at room temperature, and stirred at 27 ° C for 16 h. After the reaction was completed, the mixture was centrifuged, washed with ethanol 2-3 times, and dried in an oven at 60 ° C to obtain thiol-modified bentonite;

[0063] (4) The thiol-modified bentonite was dispersed in 1000 ml of anhydrous tetrahydrofuran, and dry nitrogen was introduced to remove water. The mixture was ultrasonically dispersed for 10 min, and 7 g of γ-butylselenolide was added for blending. The mixture was mixed at 45 ° C for 1.5 h, and then cooled to room temperature. The mixture was centrifuged, washed, dried, and ground through a 100 mesh sieve to obtain a composite adsorption material.

[0064] Comparative Example 4

[0065] This comparative example provides a method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment. The preparation method is the same as that of Example 1, except that trithiolstriazine trisodium salt and γ-butylselenolactone are blended, specifically:

[0066] (1) 100 g of bentonite ore and 0.25 g of sodium polyacrylate were added to 1000 ml of water, stirred for 1.5 h, and then allowed to stand for 30 min. The lower layer of precipitate was removed by filtration, and the upper layer of liquid was centrifuged (5000 r / min for 10 min). The lower layer of precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain purified bentonite; 100 g of purified bentonite was dispersed in 1000 ml of water, 4 g of sodium carbonate was added, and the mixture was heated at 70 ° C for 1-1.5 h. After the reaction was completed, the mixture was centrifuged (4000 r / min, 15 min), the precipitate was taken and dried at 100 ° C, and ground through a 200 mesh sieve to obtain sodium bentonite.

[0067] (2) Disperse 100 g of sodium bentonite in 1000 ml of deionized water and ultrasonically disperse it for 15 min to fully disperse it. Dissolve 50 g of 1-hexadecyl-3-methylimidazolium bromide in 100 ml of warm water to prepare a solution, which is then slowly added dropwise to the bentonite dispersion. The temperature is raised to 70°C and the reaction is continued for 1.5 h. After the reaction is completed, the solution is centrifuged, washed 2-3 times with 60°C hot water, and dried in an oven at 80°C to obtain pretreated bentonite.

[0068] (3) Disperse 100g of pretreated bentonite in 1000ml of ethanol-water solution (the volume ratio of ethanol to water is 3:1) and ultrasonically disperse it for 20min to fully disperse it. Dissolve 11g of trithiolsatizine trisodium salt and 7g of γ-butylselenolactone in 100ml of ethanol-water solution to prepare a mixed solution, and stir it mechanically at room temperature to completely dissolve it. Slowly add the mixed solution dropwise to the bentonite dispersion. After the addition is complete, stir it mechanically at room temperature for 6h to fully mix the functional components with the bentonite. After the reaction is completed, centrifuge (3500r / min, 15min), wash it twice with ethanol to remove excess functional components, dry it in an oven at 60℃ for 10h, and grind it through a 100-mesh sieve to obtain a composite adsorbent material.

[0069] Performance testing

[0070] The adsorption capacity of the composite adsorbent prepared in the above examples and comparative examples was tested. The main method was as follows: the multi-stage composite adsorbent was placed in simulated wastewater containing 10 mg / L Hg 2+ 、15mg / LCd 2+ and 20mg / LPb 2+ The mass ratio of the composite adsorbent material to the simulated wastewater was 1g:1000ml. After stirring at room temperature for 30 minutes, the composite adsorbent material was separated. The concentration of pollutants in the simulated wastewater was then tested and the removal rate was calculated. The results are shown in Table 1.

[0071] Table 1 Performance test

[0072]

[0073]

[0074] As can be seen from Table 1, the composite adsorption material prepared by the technical solution of this embodiment has good adsorption performance for metal ions and is superior to the adsorbent of the comparative example.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment, characterized in that: The following steps are involved: S1. Disperse sodium bentonite in deionized water, add an intercalant, and heat to 60-80° C. for 1-2 hours to obtain pretreated bentonite. S2. Dispersing the pretreated bentonite in an ethanol aqueous solution, adding trithiodisulfide s-triazine trisodium salt, and stirring at 25-30° C. for 14-18 hours to obtain thiol-modified bentonite; S3, dispersing the mercapto-modified bentonite in ethanol, ultrasonically dispersing, adding an aminosilane coupling agent dropwise, and reacting at 70-90° C. for 4-5 hours under nitrogen protection to obtain amino-modified bentonite; S4. Disperse the amino bentonite in anhydrous tetrahydrofuran, add γ-butylselenolactone, and react at 40-50° C. for 1-2 hours under nitrogen protection to obtain the composite adsorption material.

2. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 1, wherein: In step S1, the mass ratio of sodium bentonite to intercalant is 1:0.45-0.55, and the intercalant is 1-hexadecyl-3-methylimidazolium bromide.

3. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 1, wherein: In step S2, the mass ratio of the pretreated bentonite to the trisodium trithiodiphenylamine is 1:0.08-0.

15.

4. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 1, wherein: In step S3, the mass ratio of the mercapto-modified bentonite to the aminosilane coupling agent is 1:0.06-0.

12.

5. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 4, wherein: The aminosilane coupling agent is (3-aminopropyl)trimethoxysilane or (3-aminopropyl)triethoxysilane.

6. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 1, wherein: In step S4, the mass ratio of the amination bentonite to γ-butylselenolactone is 1:0.04-0.

1.

7. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 1, wherein: In step S1, the preparation method of sodium bentonite includes: S11, adding bentonite ore and sodium polyacrylate into water, stirring and then allowing to stand, filtering, centrifuging, and drying to obtain purified bentonite; S12. The purified bentonite is dispersed in water, sodium carbonate is added, and the mixture is heated at 60-80° C. for 1-1.5 hours to obtain sodium bentonite.

8. The method for preparing a highly selective composite adsorption material for petrochemical wastewater treatment according to claim 7, wherein: In step S11, the amount of sodium polyacrylate added is 0.2-0.3% of the mass of the original bentonite ore; in step S12, the amount of sodium carbonate added is 3-5% of the mass of the purified bentonite.

9. A highly selective composite adsorption material for petrochemical wastewater treatment, characterized by: The highly selective composite adsorption material is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the highly selective composite adsorption material according to claim 9 in the purification of petrochemical wastewater.

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