Multipurpose wastewater purifying agent and preparation method thereof

Abstract

The invention relates to the technical field of wastewater treatment, and particularly discloses a multipurpose wastewater purifying agent and a preparation method thereof. The multipurpose wastewater purifying agent is prepared from the following components in percentage by mass: 30 to 50 percent of modified bentonite adsorbent, 30 to 50 percent of activated carbon, 3 to 10 percent of polyacrylamide and 3 to 5 percent of ammonium persulfate, the modified bentonite adsorbent is obtained by modifying bentonite through ionic liquid, and the ionic liquid comprises sulfydryl-containing ionic liquid and modified ionic liquid; the preparation method of the modified ionic liquid comprises the following steps: mixing an imidazolium ionic liquid with salicylic acid, adding a catalyst, carrying out a heating reaction for a period of time, and carrying out post-treatment to obtain the modified ionic liquid. The purifying agent provided by the invention has excellent wastewater treatment capacity, and can be used for treating petrochemical engineering and domestic multi-source wastewater.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and more specifically, it relates to a multi-purpose wastewater purifying agent and a preparation method thereof, which are particularly suitable for efficiently adsorbing various heavy metal ions and organic pollutants in petrochemical wastewater and domestic sewage simultaneously. Background Art

[0002] With the advancement of the industrial revolution, dangerous industrial pollutants are discharged into the environment, seriously damaging human health and the ecosystem. Specifically, industries such as textiles, printing, petroleum, paint, and pharmaceuticals that use large amounts of solvents and organic chemicals may pollute surface water, groundwater, and seawater. Especially the problem of heavy metal pollution, the heavy metals in wastewater have the characteristics of long-term persistent toxicity and non-biodegradability, and can cause serious harm to human health through pollution of soil, water, air, especially the food chain.

[0003] Due to its unique lamellar structure and stable physical and chemical properties, bentonite is regarded as a good adsorbent material by domestic and foreign scholars. Modified bentonite is obtained by modifying bentonite through different methods such as organic and inorganic methods, and it has good adsorption effects on heavy metals, pesticides, dyes, organic matters, etc. in wastewater.

[0004] Ionic liquids are low-melting organic salts composed entirely of ions. As a "green solvent", they can dissolve polar and non-polar organic and inorganic substances, are easy to separate, and can be recycled. Immobilizing ionic liquids can obtain supported ionic liquids or solid substances with an ionic liquid structure on the surface, which combines the advantages of solid-phase carrier materials while maintaining the physical and chemical properties of the ionic liquids themselves.

[0005] There have been reports on the use of adsorbents prepared from supported ionic liquids for heavy metal ions, but the existing adsorbents of supported ionic liquids generally have problems of single treatment function and single adsorption selectivity, and cannot fully adsorb and treat all heavy metal ions in wastewater, or cannot effectively remove the organic matters in wastewater. Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a multi-purpose wastewater purifying agent and a preparation method thereof. The provided wastewater purifying agent effectively solves the defect of single function of the existing purifying agent, and provides an innovative path for the low-cost integrated treatment of complex industrial wastewater.

[0007] In a first aspect, the present application provides an ionic liquid for wastewater treatment, adopting the following technical solution:

[0008] A modified ionic liquid, obtained by modifying an imidazole-based ionic liquid with salicylic acid as a functional improver. The specific preparation steps are as follows:

[0009] Mix an imidazole-based ionic liquid with salicylic acid, add a catalyst, heat and react for a period of time, and then perform post-treatment to obtain a modified ionic liquid.

[0010] Preferably, the imidazole-based ionic liquid is 1-vinyl-3-ethylimidazolium hexafluorophosphate.

[0011] Preferably, the molar ratio of salicylic acid to the imidazole-based ionic liquid is 1:(1 - 1.1), preferably 1:(1 - 1.05), and more preferably 1:1.05.

[0012] Preferably, the catalyst is at least one of methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, and solid superacid.

[0013] Preferably, based on the mass of salicylic acid, the dosage of the catalyst is 0.1 - 0.5 wt%; preferably 0.2 - 0.4 wt%, and more preferably 0.3 wt%.

[0014] Preferably, the temperature of the heating reaction is 120 - 140 °C, preferably 130 - 140 °C, and more preferably 140 °C.

[0015] Preferably, the time of the heating reaction is 12 - 14 h, preferably 12 h.

[0016] In a second aspect, the present application provides an adsorbent for wastewater treatment, adopting the following technical solution:

[0017] An adsorbent is obtained by using bentonite as an adsorption substrate and co-modifying it with a mercapto-containing ionic liquid and the above-prepared modified ionic liquid. The specific preparation steps are as follows:

[0018] Disperse bentonite in water, add a mercapto-containing ionic liquid and a modified ionic liquid, heat and react for a period of time, and then perform post-treatment to obtain the adsorbent.

[0019] Preferably, the heating temperature is 60 - 80 °C and the heating time is 6 - 12 h.

[0020] Furthermore, before the modification of the bentonite, acid activation and organic intercalation treatment are successively carried out to enhance the ion exchange ability of the bentonite for metal ions in wastewater and the hydrophobic adsorption ability for organic pollutants. The specific treatment steps are as follows:

[0021] Mix bentonite with hydrochloric acid, heat and stir for a period of time, then centrifuge and wash to obtain acidified bentonite. Add the acidified bentonite to an ethanol solution of cetyltrimethylammonium bromide, perform ultrasonic treatment for a period of time, and then heat and reflux to obtain organically intercalated bentonite.

[0022] Preferably, the concentration of hydrochloric acid is 3 - 5 mol / L, and the mass ratio of bentonite to hydrochloric acid is 1:(10 - 15).

[0023] Preferably, the heating temperature after mixing bentonite and hydrochloric acid is 60 - 80 °C, and the heating time is 2 - 4 h.

[0024] Preferably, the molar ratio of acidified bentonite to cetyltrimethylammonium bromide is 1:(0.2 - 0.5).

[0025] Preferably, the ultrasonic frequency after mixing acidified bentonite and cetyltrimethylammonium bromide is 20 - 25 kHz, the power is 50 - 100 W, the ultrasonic time is 0.5 - 1 h, the heating temperature is 60 - 80 °C, and the reflux time is 8 - 12 h.

[0026] Bentonite is a 2:1 type layered structure composed of two layers of silicon oxygen tetrahedron sheets and one layer of aluminum oxygen octahedron sheets. This structure endows bentonite with a large specific surface area and good adsorption performance, enabling it to effectively adsorb organic pollutants in wastewater. However, the layer spacing of bentonite is relatively fixed, which to a certain extent limits the number of its adsorption sites and adsorption efficiency. Currently, there are many ways to solve this problem, including but not limited to intercalating bentonite with cationic surfactants or activating bentonite with acids, etc., to increase the layer spacing. This application provides a method for modifying bentonite, using functionalized ionic liquids to conduct composite immobilization modification on bentonite. The obtained modified bentonite is used as a wastewater adsorbent, which can comprehensively adsorb various metal ions and also has excellent adsorption ability for organic pollutants in wastewater.

[0027] In the third aspect, this application provides a multi - purpose wastewater purifying agent, adopting the following technical solution:

[0028] A multi - purpose wastewater purifying agent contains the following components in mass percentages: 30 - 50% of modified bentonite adsorbent, 30 - 50% of activated carbon, 3 - 10% of polyacrylamide, and 3 - 5% of ammonium persulfate.

[0029] In the fourth aspect, this application provides a preparation method of a multi - purpose wastewater purifying agent, adopting the following technical solution:

[0030] A preparation method of a multi - purpose wastewater purifying agent includes the following steps: mixing the modified bentonite adsorbent, activated carbon, polyacrylamide, and ammonium persulfate, and stirring evenly to obtain it.

[0031] In summary, this application has the following beneficial effects:

[0032] (1) This application uses the method of composite immobilization of bentonite with multi-functional ionic liquids to enhance the adsorption capacity of the adsorbent for pollutants in wastewater and achieve the directional adsorption of different pollutants; by modifying bentonite through acid activation and organic intercalation, the ion exchange capacity of bentonite for metal ions and the hydrophobic adsorption capacity for organic pollutants are enhanced.

[0033] (2) This application provides a preparation method of functionalized ionic liquids, which is obtained by modifying imidazole-based ionic liquids with salicylic acid as a functional improver. The obtained modified ionic liquids have good adsorption capacities for metal ions and organic pollutants, as well as excellent elution and recycling adsorption performances.

[0034] (3) This application provides a purifying agent formulation, which has good treatment effects on petrochemical wastewater, domestic sewage, etc., especially excellent adsorption treatment effects on metal ions and organic pollutants in wastewater. Detailed implementation manners

[0035] The following specific examples illustrate the implementation manners of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0036] In addition, it should be understood that one or more method steps mentioned in this application do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these clearly mentioned steps, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is only a convenient tool for identifying each method step, rather than restricting the arrangement order of each method step or the scope of implementation of this application. The change or adjustment of their relative relationship, without substantial change in technical content, should also be regarded as the scope of implementation of this application.

[0037] If the specific experimental conditions are not specified in the examples, they are usually in accordance with the conventional conditions in the art or the conditions recommended by reagent companies; the materials, reagents, etc. used in the examples, unless otherwise specified, can be obtained through commercial channels.

[0038] Example 1

[0039] Preparation of modified ionic liquid: Weigh 147.48 g of 1-vinyl-3-ethylimidazolium hexafluorophosphate (purchased from Shanghai Moni Chemical Technology Co., Ltd.) and 69.06 g of salicylic acid, add 16.81 g of methanesulfonic acid, and heat under reflux at 140 °C for 12 h. Add 300 mL of n-heptane, transfer the mixture to a separatory funnel to separate the organic layer from the catalyst, and remove the catalyst layer. The organic phase is washed three times with deionized water, once with saturated brine, dried over anhydrous sodium sulfate, filtered by suction, and the resulting filtrate is distilled under reduced pressure at 130 °C to remove the solvent. Finally, 152.35 g of modified ionic liquid is obtained with a yield of 75%.

[0040] The NMR results of the product are as follows: 1 H NMR(400MHz,DMSO-d6)=12.447(s,1H),9.743(s,1H),7.829(d,J=8.0Hz,1H),7.534(t,J=8.0Hz,1H),7.349(d,J=8.0Hz,1H),7.313(s,1H),7.109(s,1H),6.981(s,1H),4.717(t,J=7.5Hz,1H),4.510(t,J=7.5Hz,1H),3.439(q,J=7.0Hz,2H),1.267(t,J=7.0Hz,3H).

[0041] The IR results of the product are as follows: IR(KBr,υ,cm -1 ):3451–2506(br,s,-COOH&-OH),2953(m,sp 3 C-H),2874(m,sp 3 C-H),1709(s,C=O),1601(m,C=C),1585(m,C=N / C=C),1464(m,δCH2),1383(m,δ s CH3),1252(m,υC-O),857(s,υP-F).

[0042] The structural formula of the product is:

[0043] Example 2

[0044] Preparation of modified bentonite adsorbent: Add 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) to 100 ml of deionized water and ultrasonically treat for 0.5 h. Add 1 g of the modified ionic liquid prepared in Example 1 and 1 g of trioctylmethylammonium 2-mercaptobenzoate (purchased from Shanghai Moni Chemical Technology Co., Ltd.), heat to 70 °C and stir for 12 h. After cooling, filter by suction and wash, and obtain the modified bentonite adsorbent after drying.

[0045] Example 3

[0046] Preparation of modified bentonite adsorbent: 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) was added to 50 g of 3 mol / L hydrochloric acid solution, stirred at 70 °C for 3 h, centrifuged and washed until neutral to obtain acidified bentonite; according to the molar ratio of 1:0.5, the acidified bentonite was added to an ethanol solution of 1 mol / L cetyltrimethylammonium bromide, and ultrasonicated for 45 min under the conditions of 20 kHz and 75 w, heated to 70 °C and refluxed for 8 h to obtain organically intercalated bentonite.

[0047] 5 g of the organically intercalated bentonite was added to 100 ml of deionized water and ultrasonicated for 0.5 h, 1 g of the modified ionic liquid prepared in Example 1 and 1 g of trioctylmethylammonium 2-mercaptobenzoate (purchased from Mony Chemical Technology (Shanghai) Co., Ltd.) were added, heated to 70 °C and stirred for 12 h. After cooling, it was filtered and washed, and dried to obtain the modified bentonite adsorbent.

[0048] Example 4

[0049] Preparation of crosslinked modified bentonite adsorbent: 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) was added to 50 g of 3 mol / L hydrochloric acid solution, stirred at 70 °C for 3 h, centrifuged and washed until neutral to obtain acidified bentonite; according to the molar ratio of 1:0.5, the acidified bentonite was added to an ethanol solution of 1 mol / L cetyltrimethylammonium bromide, and ultrasonicated for 45 min under the conditions of 20 kHz and 75 w, heated to 70 °C and refluxed for 8 h to obtain organically intercalated bentonite.

[0050] 5 g of the organically intercalated bentonite was added to 100 ml of deionized water and ultrasonicated for 0.5 h, 1 g of the modified ionic liquid prepared in Example 1 and 1 g of trioctylmethylammonium 2-mercaptobenzoate (purchased from Mony Chemical Technology (Shanghai) Co., Ltd.) were added, heated to 70 °C and stirred for 12 h. After cooling, it was filtered and washed, and dried to obtain the modified bentonite adsorbent.

[0051] According to the solid-liquid ratio of 1 g:15 mL, the modified bentonite adsorbent was dispersed in absolute ethanol, 10% of the mass of the modified bentonite adsorbent was added with epichlorohydrin, stirred evenly, 0.1 mol / L NaOH solution was added dropwise, the pH was adjusted to 9-10, under nitrogen protection, the temperature was raised to 80 °C, and stirred for 2 h; after the reaction, the pH was adjusted to neutral, centrifuged and washed, and dried in vacuo at 60 °C to obtain the crosslinked modified bentonite adsorbent.

[0052] Comparative Example 1

[0053] Preparation of organic intercalated bentonite: 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) was added to 50 g of 3 mol / L hydrochloric acid solution, stirred at 70 °C for 3 h, centrifuged and washed until neutral to obtain acidified bentonite; according to the molar ratio of 1:0.5, the acidified bentonite was added to an ethanol solution of 1 mol / L cetyltrimethylammonium bromide, and ultrasonically treated for 45 min at 20 kHz and 75 w, heated to 70 °C and refluxed for 8 h to obtain organic intercalated bentonite.

[0054] Comparative Example 2

[0055] Preparation of modified bentonite adsorbent: 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) was added to 50 g of 3 mol / L hydrochloric acid solution, stirred at 70 °C for 3 h, centrifuged and washed until neutral to obtain acidified bentonite; according to the molar ratio of 1:0.5, the acidified bentonite was added to an ethanol solution of 1 mol / L cetyltrimethylammonium bromide, and ultrasonically treated for 45 min at 20 kHz and 75 w, heated to 70 °C and refluxed for 8 h to obtain organic intercalated bentonite.

[0056] 5 g of the organic intercalated bentonite was added to 100 ml of deionized water and ultrasonically treated for 0.5 h, 1 g of the modified ionic liquid prepared in Example 1 was added, heated to 70 °C and stirred for 12 h, after cooling, filtered and washed by suction, and dried to obtain the modified bentonite adsorbent.

[0057] Comparative Example 3

[0058] Preparation of modified bentonite adsorbent: 5 g of bentonite (purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS: 1302-78-9) was added to 50 g of 3 mol / L hydrochloric acid solution, stirred at 70 °C for 3 h, centrifuged and washed until neutral to obtain acidified bentonite; according to the molar ratio of 1:0.5, the acidified bentonite was added to an ethanol solution of 1 mol / L cetyltrimethylammonium bromide, and ultrasonically treated for 45 min at 20 kHz and 75 w, heated to 70 °C and refluxed for 8 h to obtain organic intercalated bentonite.

[0059] 5 g of the organic intercalated bentonite was added to 100 ml of deionized water and ultrasonically treated for 0.5 h, 1 g of trioctylmethylammonium 2-mercaptobenzoate (purchased from Mery Chemical Technology (Shanghai) Co., Ltd.) was added, heated to 70 °C and stirred for 12 h, after cooling, filtered and washed by suction, and dried to obtain the modified bentonite adsorbent.

[0060] Adsorption performance test:

[0061] Prepare simulated wastewater (containing 5 μg / mL Cu 2+ 、50 μg / mL Pb2+ 、 30 μg / mL Cr 6+ 、 5 μg / mL Ni 2+ 、 40 mg / mL methyl orange), take 10 mL of simulated wastewater, add 0.1 g of adsorbent, stir for 30 min and then filter. Test the contents of various metal ions and methyl orange in the filtered simulated wastewater, and calculate the adsorption rate of the adsorbent in each example and comparative example = (ion concentration before adsorption - ion concentration after adsorption) / ion concentration before adsorption × 100%.

[0062] Table 1 Test Results of Adsorption Performance

[0063]

[0064] It can be seen from the test results in Table 1 that the adsorbent prepared in this application has adsorption universality for various metal ions, can simultaneously adsorb and remove various metal ions in wastewater, and also has good adsorption and removal effects on organic pollutants.

[0065] Cyclic Adsorption Performance Test:

[0066] The used adsorbent is eluted with 1 mL of 0.2 mol / L nitric acid solution, and the eluted adsorbent is used to adsorb and purify the simulated wastewater. After repeating this process 5 times, the adsorption rate of the adsorbent is tested, and the adsorption retention rate = fifth adsorption rate / first adsorption rate × 100% is calculated. The test results are recorded in Table 2 below.

[0067] Table 2 Test Results of Cyclic Adsorption Performance

[0068]

[0069]

[0070] It can be seen from the test results in Table 2 that the adsorbent prepared in this application still has a high adsorption retention rate after 5 cycles of use. Especially after modifying bentonite with ionic liquid and then crosslinking and immobilizing bentonite with epichlorohydrin, the adsorption retention rate of the adsorbent can reach more than 89%, which is a more preferred scheme.

[0071] Example 5

[0072] Preparation of Multi - purpose Wastewater Purifying Agent: Take 50% of the modified bentonite adsorbent prepared in Example 2, 40% of activated carbon, 6% of polyacrylamide (purchased from Shanghai Luowei Chemical Co., Ltd., specifically cationic, molecular weight 22 million, solid content ≥ 88%), and 4% of ammonium persulfate, and mix them evenly to obtain it.

[0073] Example 6

[0074] Preparation of multi - purpose wastewater purifying agent: Take 50% of the modified bentonite adsorbent prepared in Example 3, 40% of activated carbon, 6% of polyacrylamide, and 4% of ammonium persulfate, and mix them evenly to obtain the product.

[0075] Example 7

[0076] Preparation of multi - purpose wastewater purifying agent: Take 50% of the modified bentonite adsorbent prepared in Example 4, 40% of activated carbon, 6% of polyacrylamide, and 4% of ammonium persulfate, and mix them evenly to obtain the product.

[0077] Wastewater purification performance test

[0078] Weigh 1000 mL of industrial wastewater, add the multi - purpose wastewater purifying agent according to the dosage of 1.5 g / L, and conduct water quality detection 12 hours after dosing.

[0079] Among them, the COD concentration is measured by the potassium dichromate method, the total phosphorus concentration is measured by the orthophosphate colorimetric method, the ammonia nitrogen concentration is measured by the Nessler colorimetric method, and the total nitrogen concentration is measured by the alkaline potassium persulfate ultraviolet spectrophotometry. The test results are recorded in Table 3 below.

[0080] Table 3 Test results of wastewater purification performance

[0081]

[0082]

[0083] It can be seen from the test results in Table 3 that the wastewater purifying agent provided by this application has obvious removal and purification effects on COD, total phosphorus, ammonia nitrogen, and total nitrogen, especially the purification effects on COD, total phosphorus, and total nitrogen are prominent.

[0084] As mentioned above, the above are only the preferred embodiments of the present invention, and do not limit the present invention in any form or essence. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. For those skilled in the art, without departing from the spirit and scope of the present invention, any equivalent changes made by using the technical content disclosed above, such as minor modifications, decorations, and evolutions, are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications, and evolutions made to the above - mentioned embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A multi-purpose wastewater purifying agent, characterized in that, Components containing the following mass percentages: 30 - 50% of modified bentonite adsorbent, 30 - 50% of activated carbon, 3 - 10% of polyacrylamide, 3 - 5% of ammonium persulfate; The modified bentonite adsorbent is obtained by modifying bentonite with ionic liquid.

2. The multi-purpose wastewater purifying agent according to claim 1, characterized in that, The ionic liquid consists of mercapto - containing ionic liquid and modified ionic liquid; the preparation method of the modified ionic liquid is: mixing imidazole - based ionic liquid with salicylic acid, adding a catalyst, heating and reacting for a period of time, and then performing post - treatment to obtain the modified ionic liquid.

3. The multi-purpose wastewater purifying agent according to claim 2, characterized in that, The molar ratio of salicylic acid to imidazole - based ionic liquid is 1:(1 - 1.1).

4. The multi-purpose wastewater purifying agent according to claim 2, characterized in that, The catalyst uses at least one of methanesulfonic acid, p - toluenesulfonic acid, trifluoromethanesulfonic acid and solid superacid. Based on the mass of salicylic acid, the dosage of the catalyst is 0.1 - 0.5 wt%.

5. The multi-purpose wastewater purifying agent according to claim 2, wherein The temperature of the heating reaction is 120 - 140 °C, and the time of the heating reaction is 12 - 14 h.

6. The multi-purpose wastewater purifying agent according to claim 2, characterized in that The preparation method of the modified bentonite adsorbent is: dispersing bentonite in water, adding mercapto - containing ionic liquid and modified ionic liquid, heating and reacting for a period of time, and then performing post - treatment to obtain the adsorbent.

7. The multi-purpose wastewater purifying agent according to claim 6, characterized in that, The heating temperature is 60 - 80 °C, and the heating time is 6 - 12 h.

8. The multi-purpose wastewater purifying agent according to claim 6, characterized in that, Before modification, the bentonite is also subjected to acid activation and organic intercalation treatment in sequence.

9. The multi-purpose wastewater purifying agent according to claim 8, characterized in that, The steps of acid activation and organic intercalation treatment are: mixing bentonite with hydrochloric acid, heating and stirring for a period of time, centrifuging and washing to obtain acidified bentonite, adding the acidified bentonite to an ethanol solution of cetyltrimethylammonium bromide, performing ultrasonic treatment for a period of time, and then heating and refluxing to obtain organically intercalated bentonite.

10. A preparation method of the multi-purpose wastewater purifying agent according to any one of claims 1-9, characterized in that, It includes the following steps: mixing the modified bentonite adsorbent, activated carbon, polyacrylamide, and ammonium persulfate, and stirring evenly to obtain it.

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