阅读说明：本技术 一种烷基氯化铵改性钠基膨润土的制备方法及其在处理石油废水中的应用 (Preparation method of alkyl ammonium chloride modified sodium bentonite and application of alkyl ammonium chloride modified sodium bentonite in treatment of petroleum wastewater ) 是由 王顺慧 兰贵红 孙宁妍 叶欢 吴虹宇 孙乔 刘向明 程兴涛 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种烷基氯化铵改性钠基膨润土的制备方法,包括以下步骤：(1)在钠基膨润土中加入去离子水,调节pH值至7～8,然后加入四甲基氯化铵,加热搅拌至完全溶解；(2)继续加入十八烷基三甲基氯化铵溶液,在加热条件下搅拌一段时间后,冷却至室温、洗涤、抽滤、烘干、冷却后研磨过筛,即可。将改性钠基膨润土投加到含油废水中,调节pH为6～7,设定温度在45±1℃条件下反应,搅拌2～3h,含油废水中油污除去率可高达96.25％,吸附去除废水的油污废水可达标排放(GB8978-1996)。(The invention discloses a preparation method of alkyl ammonium chloride modified sodium bentonite, which comprises the following steps: (1) adding deionized water into sodium bentonite, adjusting the pH value to 7-8, then adding tetramethylammonium chloride, and heating and stirring until the mixture is completely dissolved; (2) and continuously adding the octadecyl trimethyl ammonium chloride solution, stirring for a period of time under a heating condition, cooling to room temperature, washing, performing suction filtration, drying, cooling, grinding and sieving to obtain the octadecyl trimethyl ammonium chloride. The modified sodium bentonite is added into the oily wastewater, the pH is adjusted to 6-7, the reaction is carried out at the set temperature of 45 +/-1 ℃, the stirring is carried out for 2-3 h, the oil stain removal rate in the oily wastewater can reach 96.25%, and the oil stain wastewater after the wastewater is adsorbed and removed can reach the standard discharge (GB 8978-1996).)

1. The preparation method of the alkyl ammonium chloride modified sodium bentonite is characterized by comprising the following steps:

(1) adding deionized water into sodium bentonite, adjusting the pH value to 7-8, then adding tetramethylammonium chloride, and heating and stirring until the mixture is completely dissolved;

(2) and continuously adding the octadecyl trimethyl ammonium chloride solution, stirring for a period of time under a heating condition, cooling to room temperature, washing, performing suction filtration, drying, cooling, grinding and sieving to obtain the octadecyl trimethyl ammonium chloride.

2. The preparation method of alkylammonium chloride modified sodium bentonite according to claim 1, wherein the mass-to-volume ratio of sodium bentonite to deionized water in step (1) is (45-50) g: (400-500) mL.

3. The preparation method of alkylammonium chloride modified sodium bentonite according to claim 1, wherein the mass ratio of sodium bentonite to tetramethylammonium chloride in step (1) is (45-50): 6.

4. The preparation method of alkylammonium chloride modified sodium bentonite according to claim 1, wherein the heating and stirring temperature in step (1) is 60 ℃ for 30-40 min.

5. The method for preparing alkylammonium chloride modified sodium bentonite according to claim 1, wherein the mass ratio of sodium bentonite to octadecyltrimethyl ammonium chloride in the step (2) is (45-50): (21-22), and the concentration of the solution of octadecyltrimethyl ammonium chloride is 0.042-0.044 g/mL.

6. The preparation method of alkylammonium chloride modified sodium bentonite according to claim 1, wherein the heating temperature in step (2) is 60 ℃ and the heating time is 2-2.5 h.

7. The method for preparing alkylammonium chloride modified sodium bentonite according to claim 1, wherein the solvent used in the washing process in the step (2) is a mixed solvent of deionized water and absolute ethyl alcohol in a volume ratio of 1:1, and the standard of washing is that the filtrate is 0.100-0.105 mol/L Ag₂SO₄The solution was titrated until no white precipitate was produced.

8. The preparation method of alkylammonium chloride modified sodium bentonite according to claim 1, wherein the drying temperature in step (2) is 70 ± 2 ℃ and the drying time is 24 h.

9. The application of the alkylammonium chloride modified sodium bentonite in the treatment of petroleum wastewater according to any one of claims 1-8 is characterized in that the alkylammonium chloride modified sodium bentonite is added into the oil-containing wastewater, the pH is adjusted to 6-7, the reaction is carried out at the set temperature of 45 +/-1 ℃, and the stirring is carried out for 2-3 h, so that the petroleum wastewater can reach the discharge standard.

10. The application of the alkylammonium chloride modified sodium bentonite in the treatment of petroleum wastewater according to claim 9, wherein the mass-to-volume ratio of the alkylammonium chloride modified sodium bentonite to the oily wastewater is (1-5) g: 50 mL.

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a preparation method of alkyl ammonium chloride modified sodium bentonite and application of the alkyl ammonium chloride modified sodium bentonite in treatment of petroleum wastewater.

Background

The petroleum industrial wastewater contains a large amount of hydrocarbons, and toxic substances such as phenols, polycyclic aromatic hydrocarbons and esters, and if the petroleum industrial wastewater is not properly treated, the toxic substances in the water body can be accumulated, and finally, the ecological system is damaged. The components and characteristics of the oily wastewater greatly differ from each other due to different industries, the oily wastewater has complex components, the oily wastewater is mainly divided into suspended oil, dispersed oil, emulsified oil and dissolved oil according to the particle size, the problems of water environment pollution and the like are emphasized by government departments, and strict emission requirements are made on oily wastewater, so that the method has higher practical significance and practical value on further research on the petroleum wastewater treatment technology.

The current treatment method of oily wastewater is classified by action principle and mainly comprises gravity separation method, filtration separation method, coagulation method, biological method, flotation method, adsorption separation method and the like, wherein the adsorption method usually adopts bentonite. The bentonite is a cheap, nontoxic and excellent-performance adsorbent, the content of the bentonite is second in China and accounts for 60 percent of the total amount of the world, the predicted resource amount is more than 70 hundred million tons, the bentonite is cheap, the specific surface area is large, the adsorption capacity is strong, the bentonite is called montmorillonite clay, and the theoretical molecular formula of the montmorillonite is as follows: ex (H)₂O)₄{(Al₂-X,Mgx)₂[(Si,Al)₄O₁₀](OH)₂}. Bentonite is a cheap, non-toxic, excellent adsorbent, and has many excellent characteristics, such as hydrophilicity, expansibility, adsorbability, and suspensibility, due to its large specific surface area and cation exchange volume and its surface absorbing a water filmBuoyancy, stability, etc. But the effect is not good when the oily wastewater is treated due to good hydrophilic and oleophobic properties. The modified bentonite not only can further improve the specific surface area and enlarge the interlayer spacing, but also can change the hydrophilicity so as to obviously improve the oil absorption performance, the research on the modified bentonite for treating the oily wastewater mostly uses cetyl trimethyl ammonium bromide as a modifier, for example, the CTMAB modified bentonite such as Caochun and the like is used for treating the oily wastewater, the oil removal rate reaches 85.8 percent (Caochun, in ice, Zhaoying. the research on the treatment of the oily wastewater by the modified bentonite [ J]Silicate notification, 2012, 31(6): 1382-1387); honley and the like use magnetized organically modified bentonite to investigate the adsorption performance of the material on perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in water, and find that the effect of the modified material for adsorbing PFOS is superior to the experiment that PFOA (Hongrene, butylqianyun, Sunjiang, evergreen magnetized organically modified bentonite adsorbs perfluorochemicals in water [ J]The university of Lanzhou traffic, 2021,40(02): 107-.

Therefore, how to further improve the oil absorption performance of bentonite in the petroleum wastewater treatment process is a problem which needs to be solved urgently by the technical personnel in the field.

Disclosure of Invention

In view of the above, the invention provides a preparation method of alkylammonium chloride modified sodium bentonite, which can not only improve the specific surface area of bentonite, but also change the hydrophilicity of a bentonite adsorption material and improve the oil absorption performance of the bentonite, and when the preparation method is used for treating petroleum wastewater, the oil stain removal efficiency is high and the preparation method is environment-friendly.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of alkyl ammonium chloride modified sodium bentonite comprises the following steps:

(1) adding deionized water into sodium bentonite, adjusting the pH value to 7-8, then adding tetramethylammonium chloride, and heating and stirring until the mixture is completely dissolved;

(2) and continuously adding the octadecyl trimethyl ammonium chloride solution, stirring for a period of time under a heating condition, cooling to room temperature, washing, performing suction filtration, drying, cooling, grinding and sieving to obtain the octadecyl trimethyl ammonium chloride.

The sodium bentonite is a cheap and nontoxic adsorbent with excellent performance, has good dispersibility and good hydrophilic and oleophobic properties, and has poor effect in treating oily wastewater due to the hydrophilicity of the sodium bentonite.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the mass-to-volume ratio of the sodium bentonite to the deionized water in the step (1) is (45-50) g: (400-500) mL.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the mass ratio of the sodium bentonite to the tetramethylammonium chloride in the step (1) is (45-50): 6.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the heating and stirring temperature in the step (1) is 60 ℃, and the time is 30-40 min.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the mass ratio of the sodium bentonite to the octadecyl trimethyl ammonium chloride solution in the step (2) is (45-50): (21-22) g, and the concentration of the octadecyl trimethyl ammonium chloride solution is 0.042-0.044 g/mL.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the heating temperature in the step (2) is 60 ℃, and the heating time is 2-2.5 h.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the solvent used in the washing process in the step (2) is a mixed solvent of deionized water and absolute ethyl alcohol in a volume ratio of 1:1, and the standard of washing is that the filtrate is 0.100-0.105 mol/L of Ag₂SO₄The solution was titrated until no white precipitate was produced.

Preferably, in the preparation method of the alkylammonium chloride modified sodium bentonite, the drying temperature in the step (2) is 70 +/-2 ℃, and the drying time is 24 hours.

The invention also discloses application of the alkylammonium chloride modified sodium bentonite in treatment of petroleum wastewater, the alkylammonium chloride modified sodium bentonite is added into the oil-containing wastewater, the pH is adjusted to 6-7, the reaction is carried out at the set temperature of 45 +/-1 ℃, and the stirring is carried out for 2-3 h, so that the petroleum wastewater reaches the discharge standard (GB8978-1996), and the oil stain removal rate in the oil-containing wastewater reaches 96.25%.

Preferably, in the application of the alkylammonium chloride modified sodium bentonite in the treatment of petroleum wastewater, the mass-to-volume ratio of the alkylammonium chloride modified sodium bentonite to the oily wastewater is (1-5) g: 50 mL.

According to the technical scheme, compared with the prior art, the preparation method of the alkyl ammonium chloride modified sodium bentonite is simple, low in cost, stable in chemical property and recyclable; the modified bentonite is used in the treatment process of petroleum wastewater, has the advantages of short treatment flow, convenient operation, good removal effect and environmental friendliness, and can effectively solve the problems in the treatment process of industrial oily wastewater so as to improve the treatment efficiency.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is an infrared spectrogram of sodium bentonite before and after modification of the invention, wherein (a) is the sodium bentonite infrared spectrogram; (b) the modified sodium bentonite has an infrared spectrogram;

FIG. 2 is SEM pictures of sodium bentonite before and after modification of the invention, wherein (a) and (b) are SEM pictures of sodium bentonite, and (c) and (d) are SEM pictures of sodium bentonite after modification of the invention;

FIG. 3 is XRD patterns of sodium bentonite before and after modification, (a) sodium bentonite before modification, and (b) organic bentonite after modification;

FIG. 4 is a contact angle test of sodium bentonite before and after modification, (a) is a contact angle image of sodium bentonite before modification, and (b) is a contact angle image of sodium bentonite after modification;

FIG. 5 is the oil removal rate of sodium bentonite before and after modification;

FIG. 6 shows COD values of sodium bentonite before and after modification.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention relates to a method for treating oil-containing components in industrial oily wastewater, which mainly comprises the steps of adding an adsorbent alkyl modified sodium bentonite into the industrial oily wastewater, fully mixing the sodium bentonite with the wastewater, filtering after mixing for a period of time, measuring the oil content in the wastewater before and after the adsorbent is added by utilizing a COD method, and calculating the adsorption effect.

The preparation method of the alkylammonium chloride modified sodium bentonite comprises the following steps: firstly, weighing 50g of sodium bentonite, putting the sodium bentonite into a 500mL beaker, adding 200mL of deionized water, adjusting the pH value to 7-8, adding 6g of tetramethylammonium chloride, stirring until the mixture is dissolved, heating to 60 ℃, and stirring for 30-40 minutes; dissolving 21.27g of octadecyl trimethyl ammonium chloride in 50mL of pure water, adding the solution into a reaction system, stirring at 60 ℃ for 2-2.5 hours, cooling to room temperature, standing for 24 hours, washing with a mixed solvent of deionized water and absolute ethyl alcohol (V: V ═ 1:1), performing suction filtration, and repeating the above operation steps at least twice until the filtrate is 0.1mol/L of Ag₂SO₄Titrating the solution until no white precipitate is generated; drying for 24 hours at the temperature of 70 +/-2 ℃, cooling, grinding, sieving by a 90-mesh sieve to obtain the alkylammonium chloride modified sodium bentonite.

The invention researches the properties of the sodium bentonite before and after modification.

Referring to fig. 1(a), it is a sodium bentonite infrared spectrogram, and (b) the modified sodium bentonite infrared spectrogram of the invention. The infrared spectrum shows that 3650 cm and 3450cm exist before and after modification^-1The left and right peaks are assigned to the Al-OH and Si-OH stretching vibration absorption peaks. 1118,1049,476cm^-1The nearby absorption peak is derived from the vibrational expansion and contraction of Si-O; 790cm^-1The vicinity is stretching vibration from Mg-OH, and the characteristic peaks are represented before and after modification, which indicates that the original skeleton of the modified bentonite is not damaged.

The modified bentonite is added with 2923cm^-1And 2858cm^-1Left and right peaks, which represent methylene antisymmetric and symmetric stretching vibrations. At 1452cm^-1The peaks appearing on the left and right are from-CH₂-shear mode vibration and-CH₃Antisymmetric deformation vibration at 752cm^-1The weak absorption peak appearing on the left and right is the vibration absorption peak of methylene, 1220cm^-1The absorption peaks of the C-N bond are shown in the left and right, and the increased absorption peaks compared with the original bentonite indicate that the modifier is successfully attached to the sodium bentonite.

From fig. 2(a) - (d), it is seen that the sodium bentonite and the organic bentonite have irregular scale shapes on their surfaces, the basic structure of the bentonite is not changed, but the small fragments on the surface of the sodium bentonite are significantly less than that of the modified bentonite, because the long-chain ammonium groups are loaded into the bentonite, the surface of the organic bentonite is looser, the specific surface area is increased, the small particles adsorbed on the large particles are increased, and the oil absorption rate is greatly improved.

FIG. 3 is XRD patterns of sodium bentonite before and after modification, (a) sodium bentonite before modification, and (b) organic bentonite after modification; from the bragg formula, it is found that the d001 of sodium bentonite before modification is 1.40606, and the d001 of organobentonite after modification is 1.51546, and thus the addition of the modifier increases the bentonite layer spacing.

FIG. 4 is a contact angle test of sodium bentonite before and after modification, wherein the contact angle of the sodium bentonite before modification is 10.34 degrees, which shows that the sodium bentonite before modification has strong hydrophilicity; the contact angle of the modified sodium bentonite is 90.27 degrees, and the modified bentonite is not hydrophilic any more, so that the modified bentonite can better adsorb hydrophobic organic substances and improve the oil absorption performance.

FIG. 5 shows the oil removal rate of sodium bentonite before and after modification. Experiments are carried out under the optimal conditions (45 +/-1 ℃, the pH value is 6-7, the soil feeding amount is 3g, the adsorption time is 2-3 h), the oil removal rate of the organically modified bentonite reaches 96.25%, and under the same condition, the oil removal rate of the sodium bentonite is only 49.73%, which can show that the bentonite can well adsorb oil substances after being modified.

FIG. 6 shows COD values of sodium bentonite before and after modification. The experiment is carried out again under the optimal condition (45 +/-1 ℃, the pH value is 6-7, when the soil feeding amount is 3g, the adsorption time is 2-3 h), the COD removal rate of the organically modified bentonite reaches 87.20%, under the same condition, the COD removal rate of the raw soil is only 54.60%, and the result shows that the bentonite can better adsorb the oxidized pollutants in the water after being modified.

The embodiment of the invention also performs experimental research on the influence of each reaction condition on the oil stain removal rate when the alkylammonium chloride modified sodium bentonite is used for treating petroleum wastewater.

Influence of volume ratio of bentonite to oil extraction wastewater on oil stain removal rate

(1) Taking oil extraction wastewater with the concentration of 35-150 mg/L, and adjusting the pH to 7;

(2) the method comprises the following steps of (1-5) g of alkylammonium chloride modified sodium bentonite and oil extraction wastewater in a mass-volume ratio: mixing 50 mL;

(3) stirring for 2.5h at 45 ℃ under the condition of 400r/min, and after fully stirring and precipitating, the oil stain removal rate in the oil-containing wastewater reaches 91.4-95.9%.

TABLE 1

Volume ratio of bentonite to oil extraction wastewater	1g：50mL	2g：50mL	3g：50mL	4g：50mL	5g：50mL
						Oil stain removal rate/%)	91.44	95.75	95.90	95.60	93.89

Secondly, influence of reaction temperature on oil stain removal rate

(1) Taking oil extraction wastewater with the concentration of 35-150 mg/L, and adjusting the pH to 7;

(2) the method comprises the following steps of (1) mixing alkyl ammonium chloride modified sodium bentonite and oil extraction wastewater according to the mass-volume ratio of 3 g: mixing 50 mL;

(3) stirring for 2.5h at 25, 35, 45, 55 and 65 ℃ respectively under the condition of 400r/min, and fully stirring and precipitating to ensure that the oil stain removal rate in the oily wastewater reaches 81.1-96.2 percent.

TABLE 2

Reaction temperature/. degree.C	25	35	45	55	65
						Oil stain removal rate/%)	81.11	95.90	96.18	96.03	96.18

Influence of pH value on oil stain removal rate

(1) Taking oil extraction wastewater with the concentration of 35-150 mg/L, and adjusting the pH values to 5, 6, 7, 8 and 9 respectively;

(2) the method comprises the following steps of (1) mixing alkyl ammonium chloride modified sodium bentonite and oil extraction wastewater according to the mass-volume ratio of 3 g: mixing 50 mL;

(3) stirring for 2.5h at 45 ℃ and 65 ℃ under the condition of 400r/min, and after full stirring and precipitation, the oil stain removal rate in the oil-containing wastewater reaches 89.5-96.3 percent and 90.7-96.2 percent.

TABLE 3

Fourth, the influence of the reaction time on the oil stain removal rate

(1) Taking oil extraction wastewater with the concentration of 35-150 mg/L, and adjusting the pH to 6;

(2) the method comprises the following steps of (1) mixing alkyl ammonium chloride modified sodium bentonite and oil extraction wastewater according to the mass-volume ratio of 3 g: mixing 50 mL;

(3) stirring for 0.5h, 1h, 1.5h, 2h and 2.5h at 45 ℃ under the condition of 400r/min, and after fully stirring and precipitating, the oil stain removal rate in the oil-containing wastewater reaches 42.3-96.3 percent.

TABLE 4

Reaction time/h	0.5	1	1.5	2	2.5
						Oil stain removal rate/%)	42.32	70.65	89.31	95.54	96.25

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the scheme disclosed by the embodiment, the scheme corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.