An environment-friendly heavy metal wastewater treatment agent

Abstract

The present invention discloses an environment-friendly heavy metal wastewater treatment agent, belonging to the technical field of wastewater treatment, which is prepared by the following steps: S1. Mix absolute ethanol and deionized water, add γ-mercaptopropyltrimethoxysilane and stir for 5-10 min, then add porous zeolite molecular sieve, stir and react at a temperature of 50-60 °C for 6-8 h, filter, wash and dry to obtain mercapto-functionalized zeolite molecular sieve; S2. Mix the mercapto-functionalized zeolite molecular sieve and absolute ethanol, add triallyl crown ether, 1,2-ethanedithiol and benzophenone, and react under ultraviolet light irradiation for 8-15 h. Filter, wash and dry the product to obtain the environment-friendly heavy metal wastewater treatment agent, which does not contain elements (nitrogen, phosphorus) that are likely to cause water eutrophication, is more environmentally friendly than the existing heavy metal wastewater treatment agents, and has high treatment efficiency and good effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to an environment-friendly heavy metal wastewater treatment agent. Background Art

[0002] In recent years, the pollution of industrial wastewater, which has drawn increasing attention, seriously threatens people's physical health and quality of life. Electroplating is one of the industries with serious pollution. It not only generates a large amount of wastewater, but also contains a large number of metal ions in the wastewater, such as Cu 2+ , Ni 2+ , Cr 2+ , Zn 2+ , Pb 2+ , Ag 2+ , Cd 2+ etc., which are extremely toxic. Moreover, if not recycled, it will cause waste of resources. At present, the most widely used electroplating wastewater treatment technology at home and abroad is the chemical precipitation method. For example, Chinese Patent CN104973674B discloses a heavy metal wastewater treatment agent, which contains 8 parts of β-cyclodextrin, 9 parts of polyacrylamide, 3 parts of carrageenan, 8 parts of sodium humate and 70 parts of sepiolite, etc. Although the removal rate of Pb 2+ in the wastewater can reach more than 99%, the long-term use of this nitrogen-containing water treatment agent or the existing nitrogen-containing and / or phosphorus-containing water treatment agents is likely to cause eutrophication of water bodies, resulting in secondary pollution of water quality. Therefore, it is necessary to provide an environment-friendly heavy metal wastewater treatment agent without nitrogen and phosphorus elements. Summary of the Invention

[0003] The purpose of the present invention is to provide an environment-friendly heavy metal wastewater treatment agent to solve the problem that the existing heavy metal wastewater treatment agents containing elements such as nitrogen and phosphorus cause eutrophication of water bodies and secondary pollution of water quality after long-term use.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] An environment-friendly heavy metal wastewater treatment agent is prepared by the following steps:

[0006] S1. Mix absolute ethanol and deionized water, add γ-mercaptopropyltrimethoxysilane and stir for 5 - 10 min, then add porous zeolite molecular sieve. Stir and react at 50 - 60 °C for 6 - 8 h, then filter, wash and dry to obtain mercapto-functionalized zeolite molecular sieve;

[0007] S2. Mix mercapto-functionalized zeolite molecular sieve and absolute ethanol, add triallyl crown ether, 1,2-ethanedithiol and benzophenone, and react under ultraviolet light irradiation for 8 - 15 h. Filter, wash and dry the product to obtain the environment-friendly heavy metal wastewater treatment agent.

[0008] Further, the dosage ratio of absolute ethanol, deionized water, γ-mercaptopropyltrimethoxysilane, and porous zeolite molecular sieve in S1 is 60 - 80 mL : 20 - 40 mL : 0.2 - 0.4 g : 8 - 10 g.

[0009] Further, the dosage ratio of mercapto-functionalized zeolite molecular sieve, absolute ethanol, triallyl crown ether, 1,2-ethanedithiol, and benzophenone in S2 is 5 - 10 g : 130 - 150 mL : 6 g : 1 g : 0.1 - 0.2 g, and the ultraviolet light wavelength is 100 - 400 nm.

[0010] Further, the porous zeolite molecular sieve is obtained through the following steps:

[0011] Add sodium silicate and deionized water to a flask. After stirring and mixing for 10 - 15 min, successively add cetyltrimethylammonium bromide, tetramethylammonium hydroxide, and aluminum sulfate solution. After stirring for 20 min, adjust the pH to 10 with sodium hydroxide solution, then add the seed crystal ZSM-3. After stirring for 30 min, transfer it to a reaction kettle. After stirring for 2 h, heat up to 120 °C and keep the temperature constant for reaction for 48 h. Wash and filter the reaction product, dry it at 100 °C, and then place it in a muffle furnace and calcine it at 550 °C for 7 h to obtain it;

[0012] In the above process, the mass ratio of sodium silicate, deionized water, cetyltrimethylammonium bromide, tetramethylammonium hydroxide, aluminum sulfate, and the seed crystal ZSM-3 is 1 : 100 : 0.2 : 0.15 : 0.01 : 0.05 - 0.1. The aluminum sulfate solution is composed of aluminum sulfate and deionized water according to 1 g : 10 mL. The mass fraction of the sodium hydroxide solution is 40%. Using cetyltrimethylammonium bromide and tetramethylammonium hydroxide as template agents, a composite molecular sieve with microporous and mesoporous structures is prepared, which has a large surface area, strong adsorption performance, a wide range of applications, good stability, and contains silicon hydroxyl groups that are easy to modify.

[0013] Further, the triallyl crown ether is obtained through the following steps:

[0014] Add 4'-carboxybenzo-18-crown-6-ether, pentaerythritol triallyl ether, and DMF to a four-necked flask equipped with a stirrer, thermometer, water separator (connected to a spherical condenser), and air duct in sequence. After stirring for 5 min, add p-toluenesulfonic acid and hydroquinone, heat up to reflux for 6 - 8 h. After the reaction is completed, remove DMF and hydroquinone by vacuum distillation to obtain triallyl crown ether;

[0015] In the above process, the dosage ratio of 4'-carboxybenzo-18-crown-6-ether, pentaerythritol triallyl ether, DMF, p-toluenesulfonic acid and hydroquinone is 0.01 mol: 0.01 - 0.012 mol: 80 - 120 mL: 0.1 - 0.2 g: 0.1 - 0.2 g. Using 4'-carboxybenzo-18-crown-6-ether and pentaerythritol triallyl ether as substrates, through an esterification reaction, a reaction product containing three allyl structures and a crown ether structure is obtained.

[0016] Advantages of the present invention:

[0017] The present invention provides an environmentally friendly heavy metal wastewater treatment agent, which does not contain elements (nitrogen, phosphorus) that are likely to cause water eutrophication, is more environmentally friendly than existing heavy metal wastewater treatment agents, and uses porous zeolite molecular sieve as the base material. It is surface-treated with γ-mercaptopropyltrimethoxysilane to make its surface rich in mercapto groups. Then, through a thiol-ene click reaction, the mercapto-functionalized zeolite molecular sieve, triallyl crown ether and 1,2-ethanedithiol undergo a chemical reaction to form a hyperbranched polymer layer containing a crown ether structure, sulfur ether bonds and terminal mercapto groups on the surface of the porous zeolite molecular sieve, making the obtained final product have both the high adsorption performance of the porous zeolite molecular sieve and the chelating effect of chemical groups. Moreover, the hyperbranched polymer is rich in cavities, and the crown ether molecule has cavities, and heavy metal ions can be coated by the cavities. Therefore, the heavy metal wastewater treatment agent obtained by the present invention not only has high treatment efficiency and good effect, but also is environmentally friendly. Specific embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0019] Example 1

[0020] A triallyl crown ether is obtained through the following steps:

[0021] In a four-necked flask equipped with a stirrer, thermometer, water separator (connected to a spherical condenser), and air duct, 0.01 mol of 4'-carboxybenzo-18-crown-6-ether, 0.01 mol of pentaerythritol triallyl ether and 80 mL of DMF are added in sequence. After stirring for 5 minutes, 0.1 g of p-toluenesulfonic acid and 0.1 g of hydroquinone are added, and the temperature is raised to reflux for 6 hours. After the reaction is completed, DMF and hydroquinone are removed by vacuum distillation to obtain triallyl crown ether.

[0022] Example 2

[0023] A triallyl crown ether is obtained through the following steps:

[0024] Into a four-necked flask equipped with a stirrer, a thermometer, a water separator (connected to a spherical condenser), and an air duct, 0.01 mol of 4'-carboxybenzo-18-crown-6-ether, 0.012 mol of pentaerythritol triallyl ether, and 120 mL of DMF are sequentially added. After stirring for 5 min, 0.2 g of p-toluenesulfonic acid and 0.2 g of hydroquinone are added. The temperature is raised to reflux for 8 h. After the reaction ends, DMF and hydroquinone are removed by vacuum distillation to obtain the triallyl crown ether.

[0025] Example 3

[0026] An environment-friendly heavy metal wastewater treatment agent is prepared through the following steps:

[0027] S1. Mix 60 mL of absolute ethanol and 20 mL of deionized water, add 0.2 g of γ-mercaptopropyltrimethoxysilane, stir for 5 min, then add 8 g of porous zeolite molecular sieve. Stir and react at 50 °C for 6 h, then filter, wash, and dry to obtain mercapto-functionalized zeolite molecular sieve.

[0028] S2. Mix 5 g of mercapto-functionalized zeolite molecular sieve and 130 mL of absolute ethanol, add 6 g of triallyl crown ether, 1 g of 1,2-ethanedithiol, and 0.1 g of benzophenone, and react under ultraviolet light irradiation for 8 h. The product is filtered, washed, and dried to obtain the environment-friendly heavy metal wastewater treatment agent. The wavelength of the ultraviolet light is 100 - 400 nm.

[0029] Among them, the porous zeolite molecular sieve is obtained through the following steps:

[0030] Add 100 g of sodium silicate and 10 L of deionized water to the flask, stir and mix for 10 min, then sequentially add 20 g of cetyltrimethylammonium bromide, 15 g of tetramethylammonium hydroxide, and a solution composed of 1 g of aluminum sulfate and 10 mL of deionized water. Stir for 20 min, adjust the pH to 10 with 40 wt% sodium hydroxide solution, then add 5 g of seed crystal ZSM-3, stir for 30 min, transfer to a reaction kettle, stir for 2 h, then raise the temperature to 120 °C and react at a constant temperature for 48 h. The reaction product is washed with water, filtered, dried at 100 °C, and then calcined in a muffle furnace at 550 °C for 7 h.

[0031] Example 4

[0032] An environment-friendly heavy metal wastewater treatment agent is prepared through the following steps:

[0033] S1. Mix 70 mL of absolute ethanol and 30 mL of deionized water, add 0.3 g of γ-mercaptopropyltrimethoxysilane, stir for 8 min, then add 9 g of porous zeolite molecular sieve. Stir and react at 55 °C for 7 h, then filter, wash, and dry to obtain mercapto-functionalized zeolite molecular sieve;

[0034] S2. Mix 8 g of mercapto-functionalized zeolite molecular sieve and 140 mL of absolute ethanol, add 6 g of triallyl crown ether, 1 g of 1,2-ethanedithiol, and 0.15 g of benzophenone, and react under ultraviolet light irradiation for 10 h. Filter, wash, and dry the product to obtain the environmentally friendly heavy metal wastewater treatment agent. The wavelength of the ultraviolet light is 100 - 400 nm.

[0035] Among them, the porous zeolite molecular sieve is obtained through the following steps:

[0036] Add 100 g of sodium silicate and 10 L of deionized water to a flask, stir and mix for 12 min, then successively add 20 g of cetyltrimethylammonium bromide, 15 g of tetramethylammonium hydroxide, and a solution composed of 1 g of aluminum sulfate and 10 mL of deionized water. Stir for 20 min, adjust the pH to 10 with 40 wt% sodium hydroxide solution, then add 8 g of seed crystal ZSM-3, stir for 30 min, transfer to a reaction kettle, stir for 2 h, then raise the temperature to 120 °C and react at a constant temperature for 48 h. Wash and filter the reaction product, dry at 100 °C, and then calcine in a muffle furnace at 550 °C for 7 h.

[0037] Example 5

[0038] An environmentally friendly heavy metal wastewater treatment agent is prepared by the following steps:

[0039] S1. Mix 80 mL of absolute ethanol and 40 mL of deionized water, add 0.4 g of γ-mercaptopropyltrimethoxysilane, stir for 10 min, then add 10 g of porous zeolite molecular sieve. Stir and react at 60 °C for 8 h, then filter, wash, and dry to obtain mercapto-functionalized zeolite molecular sieve;

[0040] S2. Mix 10 g of mercapto-functionalized zeolite molecular sieve and 150 mL of absolute ethanol, add 6 g of triallyl crown ether, 1 g of 1,2-ethanedithiol, and 0.2 g of benzophenone, and react under ultraviolet light irradiation for 15 h. Filter, wash, and dry the product to obtain the environmentally friendly heavy metal wastewater treatment agent. The wavelength of the ultraviolet light is 100 - 400 nm.

[0041] Among them, the porous zeolite molecular sieve is obtained through the following steps:

[0042] Add 100 g of sodium silicate and 10 L of deionized water to a flask. After stirring and mixing for 15 min, sequentially add 20 g of cetyltrimethylammonium bromide, 15 g of tetramethylammonium hydroxide, and a solution composed of 1 g of aluminum sulfate and 10 mL of deionized water. After stirring for 20 min, adjust the pH to 10 with 40 wt% sodium hydroxide solution, then add 10 g of seed crystal ZSM-3. After stirring for 30 min, transfer it to a reaction kettle. After stirring for 2 h, heat it to 120 °C and keep it at a constant temperature for reaction for 48 h. Wash and filter the reaction product, dry it at 100 °C, and then calcine it in a muffle furnace at 550 °C for 7 h.

[0043] Comparative Example 1

[0044] Compared with Example 3, only replace the triallyl crown ether in Example 3 with pentaerythritol triallyl ether, and the other raw materials and preparation process are the same as those in Example 3.

[0045] Comparative Example 2

[0046] This comparative example is the mercapto-functionalized zeolite molecular sieve in Example 3.

[0047] Perform performance tests on the environmentally friendly heavy metal wastewater treatment agents obtained in Examples 3 - 5 and Comparative Examples 1 - 2.

[0048] I. Take Cu 2+ 50 mL of simulated wastewater with concentrations of 30 mg / L respectively. Fix the dosage of each group of environmentally friendly heavy metal wastewater treatment agent at 0.02 g. After stirring at room temperature for 10 min, 30 min, and 60 min, respectively measure the removal rates of heavy metal ions in each group. The results are shown in Table 1:

[0049] Table 1

[0050]

[0051] As can be seen from Table 1, compared with Comparative Example 1 and Comparative Example 2, Examples 3, 4, and 5 have 2+ higher Cu removal efficiency and better removal effect;

[0052] II. Take 50 mL of actual electroplating wastewater. Fix the dosage of each group of environmentally friendly heavy metal wastewater treatment agent at 0.05 g, the pH value at 6, the turbidity at 5.51, the Cu 2+ concentration at 84.021 mg / L, the Cr 6+ concentration at 61.973 mg / L, the Ni 2+ concentration at 24.120 mg / L, and the Zn 2+ concentration at 72.023 mg / L. Stir at room temperature for 2 h, and calculate the removal rates of heavy metal ions in each group. The results are shown in Table 2:

[0053] Table 2

[0054] Removal rate (%) Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 <![CDATA[Cu 2+ > 99.12 99.54 99.99 97.41 93.18 <![CDATA[Cr 6+ > 99.65 99.87 100 96.24 90.62 <![CDATA[Ni 2+ > 99.26 99.71 99.96 93.27 91.34 <![CDATA[Zn 2+ > 99.34 99.69 99.91 92.19 89.45

[0055] As can be seen from Table 2, compared with Example 3, the heavy metal wastewater treatment agent obtained in Comparative Example 1 has no crown ether structure, and the heavy metal wastewater treatment agent obtained in Comparative Example 2 has no crown ether, thioether structure and the characteristics of hyperbranched polymer, and cannot combine the high-efficiency adsorption performance of porous zeolite molecular sieve and the chelation of chemical groups, lacking the encapsulation effect of the cavities of hyperbranched polymer and crown ether molecules on heavy metal ions. Therefore, the effect is worse than that of Example 3. And as can be seen from Table 2, Examples 3, 4, and 5 have higher removal efficiency and better removal effect on heavy metal ions in electroplating wastewater.

[0056] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0057] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly heavy metal wastewater treatment agent, characterized in that, It is made by the following steps: S1. Mix absolute ethanol and deionized water, add γ-mercaptopropyltrimethoxysilane and stir for 5 - 10 min, then add porous zeolite molecular sieve. Stir and react at 50 - 60 °C for 6 - 8 h, then filter, wash and dry to obtain mercapto-functionalized zeolite molecular sieve; S2. Mix mercapto-functionalized zeolite molecular sieve and absolute ethanol, add triallyl crown ether, 1,2-ethanedithiol and benzophenone, and react under ultraviolet light irradiation for 8 - 15 h. Filter, wash and dry the product to obtain the environmentally friendly heavy metal wastewater treatment agent; Triallyl crown ether is obtained by the following steps: Add 4'-carboxybenzo-18-crown-6-ether, pentaerythritol triallyl ether and DMF into a flask in sequence, stir for 5 min, then add p-toluenesulfonic acid and hydroquinone, heat up to reflux for 6 - 8 h. After the reaction is completed, remove DMF and hydroquinone by vacuum distillation to obtain triallyl crown ether; The dosage ratio of absolute ethanol, deionized water, γ-mercaptopropyltrimethoxysilane and porous zeolite molecular sieve in S1 is 60 - 80 mL: 20 - 40 mL: 0.2 - 0.4 g: 8 - 10 g; The dosage ratio of mercapto-functionalized zeolite molecular sieve, absolute ethanol, triallyl crown ether, 1,2-ethanedithiol and benzophenone in S2 is 5 - 10 g: 130 - 150 mL: 6 g: 1 g: 0.1 - 0.2 g; The dosage ratio of 4'-carboxybenzo-18-crown-6-ether, pentaerythritol triallyl ether, DMF, p-toluenesulfonic acid and hydroquinone is 0.01 mol: 0.01 - 0.012 mol: 80 - 120 mL: 0.1 - 0.2 g: 0.1 - 0.2 g.

2. An environmentally friendly heavy metal wastewater treatment agent according to claim 1, characterized in that Porous zeolite molecular sieve is obtained by the following steps: Add sodium silicate and deionized water into a flask, stir and mix for 10 - 15 min, then add cetyltrimethylammonium bromide, tetramethylammonium hydroxide and aluminum sulfate solution in sequence. Stir for 20 min, adjust the pH to 10 with sodium hydroxide solution, then add seed crystal ZSM-3, stir for 30 min and transfer to a reaction kettle. Stir for 2 h, then heat up to 120 °C and react at a constant temperature for 48 h. Wash and filter the reaction product, dry at 100 °C and then calcine in a muffle furnace at 550 °C for 7 h.

3. An environmentally friendly heavy metal wastewater treatment agent according to claim 2, characterized in that, The mass ratio of sodium silicate, deionized water, cetyltrimethylammonium bromide, tetramethylammonium hydroxide, aluminum sulfate and seed crystal ZSM-3 is 1: 100: 0.2: 0.15: 0.01: 0.05 - 0.1.

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