Sewage treatment agent and preparation method thereof

Abstract

The invention discloses a sewage treatment agent and a preparation method thereof, and relates to the field of sewage treatment agents. When the sewage treatment agent is prepared, ferroferric oxide and tetrabutyl titanate are evenly mixed and then grafted with 3-chloropropyltrimethoxysilane, and pre-modified magnetic titanium dioxide is obtained; the pre-modified magnetic titanium dioxide and N, N-bis (2-chloroethyl) propan-1-amine are subjected to a reaction, and modified magnetic titanium dioxide is obtained; the preparation method comprises the following steps: reacting gallium nitrate nonahydrate with 2-aminoterephthalic acid, soaking in methanol, and grafting 6-(1H-imidazole-2-yl) pyridylaldehyde for reaction to obtain modified MIL-68 (Ga); and reacting the modified magnetic titanium dioxide with the modified MIL-68 (Ga) to obtain the sewage treatment agent. The sewage treatment agent prepared by the invention has excellent photocatalytic degradation performance, heavy metal ion complexing performance and anion adsorption performance.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment agents, in particular to a sewage treatment agent and a preparation method thereof. Background Art

[0002] At present, with the advancement of science and technology and the development of society, people's living standards have been greatly improved, but climate change and environmental problems have become increasingly prominent. Climate change and water pollution are considered to be the two most pressing environmental problems facing the world. Due to the burning of fossil fuels, the indiscriminate discharge of untreated factory wastewater, agricultural fertilization, and the frequent use of chemical substances in the production process, harmful gases, heavy metals, pesticides and other pollutants are discharged into the environment, causing serious ecological problems. For example, the enrichment of organic matter in water bodies can easily cause large-scale outbreaks of plankton (algae, etc.), causing eutrophication of water bodies, causing serious damage to the ecological environment, and at the same time causing certain impacts on people's life safety.

[0003] First, due to the traditional water treatment technology, the process is complicated, and consumes a lot of energy, it is easy to cause secondary pollution. However, the photocatalytic technology, which has developed rapidly in recent years, has brought good news to everyone in water treatment. Due to its outstanding advantages such as safety, non-toxicity, and low energy consumption, it has attracted extensive attention from scientific researchers at home and abroad, and has achieved good results in the scientific research process. Therefore, the present invention prepares a sewage treatment agent with excellent photocatalytic degradation performance. Summary of the invention

[0004] The purpose of the present invention is to provide a sewage treatment agent and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A sewage treatment agent is obtained by reacting modified magnetic titanium dioxide and modified MIL-68 (Ga).

[0007] As an optimization, the modified magnetic titanium dioxide is obtained by mixing ferrosoferric oxide and tetrabutyl titanate and then grafting 3-chloropropyltrimethoxysilane and N,N-bis(2-chloroethyl)propane-1-amine in sequence.

[0008] As an optimization, the modified MIL-68 (Ga) is obtained by reacting gallium nitrate nonahydrate with 2-aminoterephthalic acid, immersing the mixture in methanol, and then grafting 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde.

[0009] As an optimization, the gallium nitrate nonahydrate comes from Shandong Desheng New Materials Co., Ltd.

[0010] A method for preparing a sewage treatment agent comprises the following preparation steps:

[0011] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:(55-65):(155-165), perform ultrasonic dispersion for 25-35 minutes, add ammonia water in an amount of 1-3 times the mass of ferroferric oxide, continue ultrasonic dispersion for 5-15 minutes, stir at 60-70°C and 200-300 rpm for 10-20 minutes, uniformly add tetrabutyl titanate in an amount of 1-3 times the mass of ferroferric oxide within 30-50 minutes, continue stirring for 5-7 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 3-5 times respectively, and dry at 55-65°C for 11-13 hours to obtain magnetic titanium dioxide;

[0012] (2) Mix magnetic titanium dioxide and anhydrous ethanol in a mass ratio of 1:(24-26), ultrasonically disperse for 25-35 minutes, add 3-chloropropyltrimethoxysilane alcoholysis solution 3-4 times the mass of magnetic titanium dioxide, stir at 75-85°C and 410-430 r / min for 3-5 hours, filter, wash with anhydrous ethanol and deionized water for 3-5 times, and dry at 70-80°C for 6-8 hours to obtain pre-modified magnetic titanium dioxide; Mix pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane in a mass ratio of 1:(4-5):(8-10), reflux at 35-45°C for 23-25 ​​hours, heat to 45-55°C and distill under reduced pressure for 1-2 hours, wash with anhydrous ethanol and deionized water for 3-5 times, and dry at 65-75°C for 11-13 hours to obtain modified magnetic titanium dioxide;

[0013] (3) Mix hydrated gallium nitrate, 2-aminoterephthalic acid and N,N-dimethylformamide in a mass ratio of 1:(0.2-0.3):(12-13), stir at 20-30°C and 300-400 rpm for 25-35 min, add 2.25-2.27 mol / L hydrofluoric acid (1.6-1.8 times the mass of hydrated gallium nitrate), continue stirring for 25-35 min, heat to 120-130°C, continue stirring for 5-7 h, cool naturally to room temperature and filter, wash with N,N-dimethylformamide 3-5 times, and dry at 95-105°C for 4-6 h to obtain crude amino MIL-68 (Ga); soak the crude amino MIL-68 (Ga) in anhydrous methanol for 7-9 h. Change once, soak for 2 to 4 days, filter, and dry at 195 to 205°C for 9 to 11 hours to obtain activated amino MIL-68 (Ga); mix activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1: (0.3 to 0.5): (2 to 3): (25 to 35): (9 to 11), quickly freeze at -200 to -190°C, heat to 115 to 125°C and let stand for 2 to 4 days, cool naturally to room temperature and filter, wash with N, N-dimethylformamide and acetone for 3 to 5 times respectively, extract with tetrahydrofuran for 11 to 13 hours, and dry at 55 to 65°C for 11 to 13 hours to obtain modified MIL-68 (Ga);

[0014] (4) The modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane are mixed in a mass ratio of 1: (2-3): (6-8), stirred at 20-30°C and 200-300 rpm for 25-35 min, heated to 55-65°C and stirred for 23-25 ​​h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 3-5 times respectively, and dried at 60-70°C for 16-18 h to obtain a sewage treatment agent.

[0015] As an optimization, the reaction equation of the magnetic titanium dioxide in step (1) is:

[0016]

[0017] As an optimization, the 3-chloropropyltrimethoxysilane alcoholysis solution in step (2) is obtained by mixing 3-chloropropyltrimethoxysilane and a 50% ethanol solution by volume in a mass ratio of 1:9, adjusting the solution pH to 3.5 with glacial acetic acid, and ultrasonically dispersing for 30 minutes.

[0018] As an optimization, the reaction equation of the pre-modified magnetic titanium dioxide in step (2) is:

[0019]

[0020] As an optimization, the reaction equation for the modified magnetic titanium dioxide in step (2) is:

[0021]

[0022] As an optimization, the reaction equation for activating amino MIL-68 (Ga) in step (3) is:

[0023]

[0024] As an optimization, the reaction equation for the modified MIL-68(Ga) in step (3) is:

[0025]

[0026] As an optimization, the reaction equation of the sewage treatment agent in step (4) is:

[0027]

[0028] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0029] When preparing the sewage treatment agent, the present invention comprises the following steps: uniformly mixing ferrosoferric oxide and tetrabutyl titanate, and then grafting 3-chloropropyltrimethoxysilane to obtain pre-modified magnetic titanium dioxide; reacting the pre-modified magnetic titanium dioxide with N,N-bis(2-chloroethyl)propane-1-amine to obtain modified magnetic titanium dioxide; reacting gallium nitrate nonahydrate with 2-aminoterephthalic acid, and then immersing the mixture in methanol, and then grafting 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde to obtain modified MIL-68(Ga); and reacting the modified magnetic titanium dioxide with the modified MIL-68(Ga) to obtain the sewage treatment agent.

[0030] First, ferrosoferric oxide and tetrabutyl titanate are mixed and then grafted with 3-chloropropyltrimethoxysilane to obtain pre-modified magnetic titanium dioxide; the pre-modified magnetic titanium dioxide and N,N-bis(2-chloroethyl)propane-1-amine are reacted to obtain modified magnetic titanium dioxide; a core-shell magnetic titanium dioxide is prepared by a sol-gel method, which adsorbs suspended particles and heavy metal ions and precipitates them while expanding the light absorption range of titanium dioxide, enhancing photocatalytic performance, and improving the heavy metal ion complexing performance and photocatalytic degradation performance of the sewage treatment agent; a quaternary ammonium branching reaction is carried out using N,N-bis(2-chloroethyl)propane-1-amine to obtain a modified magnetic titanium dioxide with a hyperbranched structure, and the quaternary ammonium cation can produce electrical neutralization and electrostatic adsorption with negatively charged particles, aggregate pollutants and enhance the precipitation effect, and at the same time, the precipitation net capture effect of the hyperbranched structure has a strong physical adsorption effect, thereby improving the anion adsorption performance of the sewage treatment agent;

[0031] Secondly, gallium nitrate nonahydrate and 2-aminoterephthalic acid are reacted and then immersed in methanol, and then 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde is grafted to obtain modified MIL-68(Ga); modified magnetic titanium dioxide and modified MIL-68(Ga) are reacted to obtain a sewage treatment agent; activated MIL-68(Ga) is obtained by pore modification to provide as many reaction sites as possible, expand the light absorption range of titanium dioxide, enhance the photocatalytic activity of titanium dioxide, and improve the photocatalytic degradation performance of the sewage treatment agent; 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde is grafted by Schiff base reaction to form a stable five-membered ring structure that can complex heavy metal ions, thereby improving the heavy metal ion complexing performance of the sewage treatment agent; chlorine is reacted with the secondary amine on pyridine to form a stable chemical bond between the modified magnetic titanium dioxide and the modified MIL-68(Ga), thereby improving the stability of the sewage treatment agent. DETAILED DESCRIPTION

[0032] 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 described embodiments 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 work are within the scope of protection of the present invention.

[0033] Embodiment 1:

[0034] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0035] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:55:155, ultrasonically disperse for 25 minutes, add ammonia water with a mass of 1 times that of ferroferric oxide, continue ultrasonication for 5 minutes, stir at 60°C and 200 rpm for 20 minutes, uniformly add tetrabutyl titanate with a mass of 1 times that of ferroferric oxide within 30 minutes, continue stirring for 7 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 3 times respectively, and dry at 55°C for 13 hours to obtain magnetic titanium dioxide;

[0036] (2) Magnetic titanium dioxide and anhydrous ethanol were mixed in a mass ratio of 1:24, ultrasonically dispersed for 25 minutes, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 3 times that of magnetic titanium dioxide was added, stirred at 75°C and 410 r / min for 5 hours, filtered, washed with anhydrous ethanol and deionized water for 3 times, and dried at 70°C for 8 hours to obtain pre-modified magnetic titanium dioxide; pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane were mixed in a mass ratio of 1:4:8, refluxed at 35°C for 25 hours, heated to 45°C and distilled under reduced pressure for 2 hours, washed with anhydrous ethanol and deionized water for 3 times, and dried at 65°C for 13 hours to obtain modified magnetic titanium dioxide;

[0037] (3) Gallium nitrate hydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:0.2:12, stirred at 20°C and 300 rpm for 35 min, 2.25 mol / L hydrofluoric acid (1.6 times the mass of gallium nitrate hydrate) was added, and stirring was continued for 35 min. The temperature was raised to 120°C, and stirring was continued for 7 h. After naturally cooling to room temperature, it was filtered, washed with N,N-dimethylformamide for 3 times, and dried at 95°C for 6 h to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol for 7 min. h, filtered after soaking for 4 days, and dried at 195°C for 11h to obtain activated amino MIL-68 (Ga); mixed activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1:0.3:2:25:9, quickly frozen at -200°C, heated to 115°C and allowed to stand for 4 days, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide and acetone for 3 times respectively, extracted with tetrahydrofuran by Soxhlet for 11h, and dried at 55°C for 13h to obtain modified MIL-68 (Ga);

[0038] (4) The modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.1:6, stirred at 20°C and 200 rpm for 35 min, heated to 55°C and stirred for 25 h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 3 times respectively, and dried at 60°C for 18 h to obtain a sewage treatment agent.

[0039] Embodiment 2:

[0040] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0041] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:60:160, ultrasonically disperse for 30 minutes, add ammonia water twice the mass of ferroferric oxide, continue ultrasonication for 10 minutes, stir at 65°C and 250 rpm for 15 minutes, uniformly add tetrabutyl titanate twice the mass of ferroferric oxide within 40 minutes, continue stirring for 6 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 4 times respectively, and dry at 60°C for 12 hours to obtain magnetic titanium dioxide;

[0042] (2) Magnetic titanium dioxide and anhydrous ethanol were mixed in a mass ratio of 1:25, ultrasonically dispersed for 30 minutes, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 3.5 times that of the magnetic titanium dioxide was added, stirred at 80°C and 420 r / min for 4 hours, filtered, washed with anhydrous ethanol and deionized water for 4 times, and dried at 75°C for 7 hours to obtain pre-modified magnetic titanium dioxide; pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane were mixed in a mass ratio of 1:4.5:9, refluxed at 40°C for 24 hours, heated to 50°C and distilled under reduced pressure for 1.5 hours, washed with anhydrous ethanol and deionized water for 4 times, and dried at 70°C for 12 hours to obtain modified magnetic titanium dioxide;

[0043] (3) Gallium nitrate hydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:0.25:12.5, stirred at 25°C and 350 rpm for 30 min, 2.26 mol / L hydrofluoric acid (1.7 times the mass of gallium nitrate hydrate) was added, and stirring was continued for 30 min. The temperature was raised to 125°C, and stirring was continued for 6 h. After natural cooling to room temperature, it was filtered, washed with N,N-dimethylformamide for 4 times, and dried at 100°C for 5 h to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol for 8 h, filtered after soaking for 3 days, and dried at 200°C for 10 h to obtain activated amino MIL-68 (Ga); mixed activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1:0.4:2.5:30:10, quickly frozen at -195°C, heated to 120°C and allowed to stand for 3 days, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide and acetone for 4 times respectively, extracted with tetrahydrofuran for 12 h, and dried at 60°C for 12 h to obtain modified MIL-68 (Ga);

[0044] (4) The modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.2:7, stirred at 25°C and 250 rpm for 30 min, heated to 60°C and stirred for 24 h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 4 times respectively, and dried at 65°C for 17 h to obtain a sewage treatment agent.

[0045] Embodiment 3:

[0046] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0047] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:65:165, ultrasonically disperse for 35 minutes, add ammonia water 3 times the mass of ferroferric oxide, continue ultrasonication for 15 minutes, stir at 70°C and 300 rpm for 10 minutes, uniformly add tetrabutyl titanate 3 times the mass of ferroferric oxide within 50 minutes, continue stirring for 5 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 5 times respectively, and dry at 65°C for 11 hours to obtain magnetic titanium dioxide;

[0048] (2) Magnetic titanium dioxide and anhydrous ethanol were mixed in a mass ratio of 1:26, ultrasonically dispersed for 35 minutes, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 4 times that of magnetic titanium dioxide was added, stirred at 85°C and 430 r / min for 3 hours, filtered, washed with anhydrous ethanol and deionized water for 5 times, and dried at 80°C for 6 hours to obtain pre-modified magnetic titanium dioxide; pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane were mixed in a mass ratio of 1:5:10, refluxed at 45°C for 23 hours, heated to 55°C and distilled under reduced pressure for 1 hour, washed with anhydrous ethanol and deionized water for 5 times, and dried at 75°C for 11 hours to obtain modified magnetic titanium dioxide;

[0049] (3) Gallium nitrate hydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:0.3:13, stirred at 30°C and 400 rpm for 25 min, 2.27 mol / L hydrofluoric acid (1.8 times the mass of gallium nitrate hydrate) was added, stirring was continued for 25 min, the temperature was raised to 130°C, stirring was continued for 5 h, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide for 5 times, and dried at 105°C for 4 h to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol for 9 h, filtered after soaking for 2 days, and dried at 205°C for 9h to obtain activated amino MIL-68 (Ga); mixed activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1:0.5:3:35:11, quickly frozen at -190°C, heated to 125°C and allowed to stand for 2 days, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide and acetone for 5 times respectively, extracted with tetrahydrofuran for 13h, and dried at 65°C for 11h to obtain modified MIL-68 (Ga);

[0050] (4) The modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.3:8, stirred at 30°C and 300 rpm for 25 min, heated to 65°C and continued to stir for 23 h, naturally cooled to room temperature and then filtered, washed with deionized water and anhydrous ethanol for 5 times respectively, and dried at 70°C for 16 h to obtain a sewage treatment agent.

[0051] Comparative Example 1:

[0052] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0053] (1) Titanium dioxide and anhydrous ethanol were mixed in a mass ratio of 1:25, ultrasonically dispersed for 30 minutes, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 3.5 times that of titanium dioxide was added, stirred at 80°C and 420 r / min for 4 hours, filtered, washed with anhydrous ethanol and deionized water for 4 times, and dried at 75°C for 7 hours to obtain pre-modified titanium dioxide; pre-modified titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane were mixed in a mass ratio of 1:4.5:9, refluxed at 40°C for 24 hours, heated to 50°C and distilled under reduced pressure for 1.5 hours, washed with anhydrous ethanol and deionized water for 4 times, and dried at 70°C for 12 hours to obtain modified titanium dioxide;

[0054] (3) Gallium nitrate hydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:0.25:12.5, stirred at 25°C and 350 rpm for 30 min, 2.26 mol / L hydrofluoric acid (1.7 times the mass of gallium nitrate hydrate) was added, and stirring was continued for 30 min. The temperature was raised to 125°C, and stirring was continued for 6 h. After natural cooling to room temperature, it was filtered, washed with N,N-dimethylformamide for 4 times, and dried at 100°C for 5 h to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol for 8 h, filtered after soaking for 3 days, and dried at 200°C for 10 h to obtain activated amino MIL-68 (Ga); mixed activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1:0.4:2.5:30:10, quickly frozen at -195°C, heated to 120°C and allowed to stand for 3 days, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide and acetone for 4 times respectively, extracted with tetrahydrofuran for 12 h, and dried at 60°C for 12 h to obtain modified MIL-68 (Ga);

[0055] (4) The modified titanium dioxide, modified MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.2:7, stirred at 25°C and 250 rpm for 30 min, heated to 60°C and stirred for 24 h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 4 times respectively, and dried at 65°C for 17 h to obtain a sewage treatment agent.

[0056] Comparative Example 2:

[0057] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0058] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:60:160, ultrasonically disperse for 30 minutes, add ammonia water twice the mass of ferroferric oxide, continue ultrasonication for 10 minutes, stir at 65°C and 250 rpm for 15 minutes, uniformly add tetrabutyl titanate twice the mass of ferroferric oxide within 40 minutes, continue stirring for 6 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 4 times respectively, and dry at 60°C for 12 hours to obtain magnetic titanium dioxide;

[0059] (2) Magnetic titanium dioxide and anhydrous ethanol were mixed at a mass ratio of 1:25, ultrasonically dispersed for 30 min, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 3.5 times that of the magnetic titanium dioxide was added, stirred at 80 ° C and 420 r / min for 4 h, filtered, washed with anhydrous ethanol and deionized water for 4 times respectively, and dried at 75 ° C for 7 h to obtain pre-modified magnetic titanium dioxide;

[0060] (3) Gallium nitrate hydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:0.25:12.5, stirred at 25°C and 350 rpm for 30 min, 2.26 mol / L hydrofluoric acid (1.7 times the mass of gallium nitrate hydrate) was added, and stirring was continued for 30 min. The temperature was raised to 125°C, and stirring was continued for 6 h. After natural cooling to room temperature, it was filtered, washed with N,N-dimethylformamide for 4 times, and dried at 100°C for 5 h to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol for 8 h, filtered after soaking for 3 days, and dried at 200°C for 10 h to obtain activated amino MIL-68 (Ga); mixed activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol in a mass ratio of 1:0.4:2.5:30:10, quickly frozen at -195°C, heated to 120°C and allowed to stand for 3 days, naturally cooled to room temperature and filtered, washed with N,N-dimethylformamide and acetone for 4 times respectively, extracted with tetrahydrofuran for 12 h, and dried at 60°C for 12 h to obtain modified MIL-68 (Ga);

[0061] (4) The pre-modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.2:7, stirred at 25 °C and 250 rpm for 30 min, heated to 60 °C and continued to stir for 24 h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 4 times respectively, and dried at 65 °C for 17 h to obtain a sewage treatment agent.

[0062] Comparative Example 3:

[0063] A method for preparing a sewage treatment agent, the method comprising the following steps:

[0064] (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:60:160, ultrasonically disperse for 30 minutes, add ammonia water twice the mass of ferroferric oxide, continue ultrasonication for 10 minutes, stir at 65°C and 250 rpm for 15 minutes, uniformly add tetrabutyl titanate twice the mass of ferroferric oxide within 40 minutes, continue stirring for 6 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 4 times respectively, and dry at 60°C for 12 hours to obtain magnetic titanium dioxide;

[0065] (2) Magnetic titanium dioxide and anhydrous ethanol were mixed in a mass ratio of 1:25, ultrasonically dispersed for 30 minutes, 3-chloropropyltrimethoxysilane alcoholysis solution with a mass of 3.5 times that of the magnetic titanium dioxide was added, stirred at 80°C and 420 r / min for 4 hours, filtered, washed with anhydrous ethanol and deionized water for 4 times, and dried at 75°C for 7 hours to obtain pre-modified magnetic titanium dioxide; pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane were mixed in a mass ratio of 1:4.5:9, refluxed at 40°C for 24 hours, heated to 50°C and distilled under reduced pressure for 1.5 hours, washed with anhydrous ethanol and deionized water for 4 times, and dried at 70°C for 12 hours to obtain modified magnetic titanium dioxide;

[0066] (3) Mix hydrated gallium nitrate, 2-aminoterephthalic acid and N,N-dimethylformamide in a mass ratio of 1:0.25:12.5, stir at 25°C and 350 rpm for 30 min, add 2.26 mol / L hydrofluoric acid (1.7 times the mass of hydrated gallium nitrate), continue stirring for 30 min, heat to 125°C, continue stirring for 6 h, cool naturally to room temperature and filter, wash with N,N-dimethylformamide 4 times, dry at 100°C for 5 h, and obtain crude amino MIL-68 (Ga); soak the crude amino MIL-68 (Ga) in anhydrous methanol, change it every 8 h, filter after soaking for 3 days, and dry at 200°C for 10 h to obtain activated amino MIL-68 (Ga);

[0067] (4) The modified magnetic titanium dioxide, activated amino MIL-68 (Ga) and dichloromethane were mixed in a mass ratio of 1:1.2:7, stirred at 25 °C and 250 rpm for 30 min, heated to 60 °C and continued to stir for 24 h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 4 times respectively, and dried at 65 °C for 17 h to obtain a sewage treatment agent.

[0068] Test example:

[0069] 1. Photocatalytic degradation performance

[0070] Test method: Take 60 mg of the sewage treatment agent obtained in each embodiment and the comparative example as a sample, add the sample into 60 mL of a methylene blue solution with a concentration of 10 mg / L (C0), stir for 30 minutes in a dark place, irradiate with a 500W x-arc lamp with a filter (λ>420nm) under visible light for 180 minutes, centrifuge at 8000 rpm for 3 minutes after 30 minutes, detect the methylene blue concentration C1 with a Cary5000 ultraviolet spectrophotometer, and calculate the degradation rate = (C0-C1) / C0*100%.

[0071] 2. Heavy metal ion complexing properties

[0072] Test method: Take 10 mg of the sewage treatment agent obtained in each example and the comparative example as a sample, add the sample into 10 mL of Pb with a concentration of 100 mg / L (C0) 2+ The ion solution was shaken at 25°C and 180 rpm for 24 h, and 0.01 mol / L sodium hydroxide solution and hydrochloric acid solution were added to adjust the pH value to 7. After filtering, the Pb content in the filtrate was determined by atomic absorption spectrometry (TAS-990AFG). 2+ Ion concentration, calculate the complexation rate = (C0-C1) / C0*100%.

[0073] 3. Anion adsorption performance

[0074] Test method: Take 50 mg of the sewage treatment agent obtained in each embodiment and the comparative example as samples, mix 5 mL of sodium sulfide standard solution, 40 mL of deionized water, 5 mL of p-aminodimethylaniline solution and 1 mL of ammonium ferric sulfate solution, use a 10 mm cuvette to measure the absorbance A0 of the solution at 665 nm on a UV spectrophotometer, add the sample to avoid light, stir at 25 ° C, 200 rpm for 80 min, and then centrifuge, use Shimadzu UV-2700 spectrophotometer to measure the absorbance A1 of sulfide in the solution, and calculate the adsorption rate = (A0-A 1) / A0*100% (25 g of FeNH4(SO4)2·12H2O was dissolved in deionized water containing 5 mL of H2SO4, and then deionized water was added to obtain 200 mL of ammonium ferric sulfate solution; 2 g of p-aminodimethylaniline salt was dissolved in 700 mL of deionized water, and then 200 mL of sulfuric acid was added, and finally deionized water was added to make up to 1000 mL to obtain p-aminodimethylaniline solution; 7.5 g of Na2S·9H2O was dissolved in deionized water, and deionized water was added to make up to 1000 mL to obtain sodium sulfide standard solution).

[0075] Table 1 below shows the analysis results of the photocatalytic degradation performance, heavy metal ion complexing performance and anion adsorption performance of the sewage treatment agents of Examples 1 to 3 of the present invention and Comparative Examples 1 to 3.

[0076] Table 1

[0077] Degradation rate % Complexation rate % Adsorption rate % Example 1 72.5 94.3 98.7 Example 2 72.8 94.8 99.4 Example 3 72.6 94.5 98.9 Comparative Example 1 48.1 83.6 97.6 Comparative Example 2 70.6 94.2 26.8 Comparative Example 3 71.9 29.5 98.3

[0078] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the sewage treatment agent prepared by the present invention has good photocatalytic degradation performance, heavy metal ion complexing performance and anion adsorption performance.

[0079] By comparison, the degradation rate and complexation rate of Examples 1, 2, and 3 are higher than those of Comparative Example 1, which illustrates that the magnetic titanium dioxide with a core-shell structure is prepared by the sol-gel method, which adsorbs suspended particles and heavy metal ions and precipitates them while expanding the light absorption range of titanium dioxide, enhancing the photocatalytic performance, and improving the heavy metal ion complexation performance and photocatalytic degradation performance of the sewage treatment agent.

[0080] By comparison, the adsorption rates of Examples 1, 2, and 3 are higher than those of Comparative Example 2, indicating that the modified magnetic titanium dioxide with a hyperbranched structure is obtained by carrying out a quaternary ammonium branching reaction using N,N-bis(2-chloroethyl)propane-1-amine, and the quaternary ammonium cations can produce electrical neutralization and electrostatic adsorption with negatively charged particles, thereby aggregating pollutants and enhancing the precipitation effect. At the same time, the precipitation netting effect of the hyperbranched structure has a strong physical adsorption effect, thereby improving the anion adsorption performance of the sewage treatment agent.

[0081] By comparison, the complexing rates of Examples 1, 2, and 3 are higher than those of Comparative Example 3, indicating that 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde is grafted through the Schiff base reaction to form a stable five-membered ring structure capable of complexing heavy metal ions, thereby improving the heavy metal ion complexing performance of the sewage treatment agent.

[0082] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of 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 sewage treatment agent, characterized in that: The sewage treatment agent is obtained by reacting modified magnetic titanium dioxide and modified MIL-68 (Ga); The modified magnetic titanium dioxide is obtained by mixing ferrosoferric oxide and tetrabutyl titanate and then grafting 3-chloropropyltrimethoxysilane and N,N-bis(2-chloroethyl)propane-1-amine in sequence; The modified MIL-68 (Ga) is obtained by reacting gallium nitrate nonahydrate with 2-aminoterephthalic acid, soaking the mixture in methanol, and then grafting 6-(1H-imidazole-2-yl)pyridinecarboxaldehyde.

2. A method for preparing a sewage treatment agent, characterized in that: The method comprises the following preparation steps: (1) Mix ferroferric oxide, acetonitrile and anhydrous ethanol in a mass ratio of 1:(55-65):(155-165), perform ultrasonic dispersion for 25-35 minutes, add ammonia water in an amount of 1-3 times the mass of ferroferric oxide, continue ultrasonic dispersion for 5-15 minutes, stir at 60-70°C and 200-300 rpm for 10-20 minutes, uniformly add tetrabutyl titanate in an amount of 1-3 times the mass of ferroferric oxide within 30-50 minutes, continue stirring for 5-7 hours, cool naturally to room temperature, filter, wash with anhydrous ethanol and acetonitrile for 3-5 times respectively, and dry at 55-65°C for 11-13 hours to obtain magnetic titanium dioxide; (2) Mix magnetic titanium dioxide and anhydrous ethanol in a mass ratio of 1:(24-26), ultrasonically disperse for 25-35 minutes, add 3-chloropropyltrimethoxysilane alcoholysis solution 3-4 times the mass of magnetic titanium dioxide, stir at 75-85°C and 410-430 r / min for 3-5 hours, filter, wash with anhydrous ethanol and deionized water for 3-5 times, and dry at 70-80°C for 6-8 hours to obtain pre-modified magnetic titanium dioxide; Mix pre-modified magnetic titanium dioxide, N,N-bis(2-chloroethyl)propane-1-amine and dichloromethane in a mass ratio of 1:(4-5):(8-10), reflux at 35-45°C for 23-25 ​​hours, heat to 45-55°C and distill under reduced pressure for 1-2 hours, wash with anhydrous ethanol and deionized water for 3-5 times, and dry at 65-75°C for 11-13 hours to obtain modified magnetic titanium dioxide; (3) Gallium nitrate nonahydrate, 2-aminoterephthalic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:(0.2-0.3):(12-13), stirred at 20-30°C and 300-400 rpm for 25-35 min, added with 2.25-2.27 mol / L hydrofluoric acid (1.6-1.8 times the mass of gallium nitrate nonahydrate), continued to stir for 25-35 min, heated to 120-130°C, continued to stir for 5-7 h, cooled naturally to room temperature, filtered, and filtered with N,N -dimethylformamide for 3 to 5 times, and dried at 95 to 105°C for 4 to 6 hours to obtain crude amino MIL-68 (Ga); the crude amino MIL-68 (Ga) was soaked in anhydrous methanol, which was changed every 7 to 9 hours, and filtered after soaking for 2 to 4 days, and dried at 195 to 205°C for 9 to 11 hours to obtain activated amino MIL-68 (Ga); activated amino MIL-68 (Ga), 6-(1H-imidazole-2-yl) pyridine carboxaldehyde, acetic acid, o-dichlorobenzene and n-butanol were mixed in a mass ratio of 1:

1. 1:(0.3-0.5):(2-3):(25-35):(9-11) mix well, freeze quickly at -200--190°C, heat to 115-125°C and let stand for 2-4 days, cool naturally to room temperature and filter, wash with N,N-dimethylformamide and acetone for 3-5 times respectively, extract with tetrahydrofuran for 11-13h, dry at 55-65°C for 11-13h to obtain modified MIL-68(Ga); (4) The modified magnetic titanium dioxide, modified MIL-68 (Ga) and dichloromethane are mixed in a mass ratio of 1: (2-3): (6-8), stirred at 20-30°C and 200-300 rpm for 25-35 min, heated to 55-65°C and stirred for 23-25 ​​h, naturally cooled to room temperature and filtered, washed with deionized water and anhydrous ethanol for 3-5 times respectively, and dried at 60-70°C for 16-18 h to obtain a sewage treatment agent.

3. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation of the magnetic titanium dioxide in step (1) is:

4. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The 3-chloropropyltrimethoxysilane alcoholysis solution in step (2) is obtained by mixing 3-chloropropyltrimethoxysilane and 50% ethanol solution by volume in a mass ratio of 1:9, adjusting the pH of the solution to 3.5 with glacial acetic acid, and ultrasonically dispersing for 30 minutes.

5. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation of the pre-modified magnetic titanium dioxide in step (2) is:

6. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation for the modified magnetic titanium dioxide in step (2) is:

7. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation for the activation of amino MIL-68 (Ga) in step (3) is:

8. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation for the modified MIL-68(Ga) in step (3) is:

9. The method for preparing a sewage treatment agent according to claim 2, characterized in that: The reaction equation of the sewage treatment agent in step (4) is:

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