High-activity nanocellulose water clarifier and preparation method thereof

Abstract

The invention discloses a high-activity nanocellulose water clarifier and a preparation method thereof. The preparation method comprises the following steps: firstly, screening out nano-cellulose which is easy to disperse in an oil-water interface, carrying out etherification modification on the nano-cellulose through an alkyl methyl ester etherifying agent, and researching etherification modification conditions of the alkyl methyl ester etherifying agent, so that the prepared modified nano-cellulose has a relatively strong breaking effect on oil-in-water emulsion; meanwhile, cationic quaternary ammonium salt type side groups are introduced through etherification reaction, so that the modified nanocellulose further obtains strong charge adsorption effect on oil-containing colloid in water, and fine floc is formed to float. The nano cellulose is modified by alkyl methyl ester and quaternization, so that a high-activity nano cellulose water clarifier product can be prepared, and the nano cellulose water clarifier has a wide application prospect in the field of oil-water separation of offshore oilfields.

Description

Technical Field

[0001] The invention relates to the technical field of natural macromolecular polymer modification, and in particular to a high-activity nanocellulose water-purifying agent and a preparation method thereof. Background Art

[0002] In recent years, as people pay more and more attention to the transformation and utilization of renewable biomass resources, nanocellulose has received widespread attention due to its unique properties. Nanocellulose has the characteristics of wide sources, renewable, easy to degrade, nano-size effect and functional modification. In the modified nanocellulose-based polymer water-purifying agent, the cyclic hydrophobic groups of nanocellulose have a natural ability to capture crude oil, and after the modified charge extrusion, it is easy to form fine crude oil flocs and float up. In addition, the nanocellulose-based polymer has a low viscosity in water and is not easy to form difficult-to-recover colloids. This type of nano-scale polymer water-purifying agent has broad application prospects in the oil-water separation system of offshore oil platforms.

[0003] The light crude oil processing process is short and requires an efficient oil-water separator. However, the currently synthesized polymer water-clearing agent has a high molecular weight and slow diffusion and dissolution. The crude oil flocs formed are large in size and easily clog the hydrocyclone. The water-clearing effect is poor, which affects the oil-water separation effect and cannot meet the use needs well. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a highly active nanocellulose water purifier and a preparation method thereof. The present invention adopts etherified modified nanocellulose and introduces highly active lipophilic functional groups to achieve rapid oil-water separation, thereby meeting the oil-water separation requirements of light crude oil.

[0005] In a first aspect, the present invention provides a method for preparing a highly active nanocellulose water-purifying agent, which is achieved by adopting the following technical scheme.

[0006] A method for preparing a highly active nanocellulose water-clearing agent, the water-clearing agent comprising the following raw materials in parts by weight: 200-230 parts of nanocellulose, 5-7 parts of an alkyl methyl ester etherifying agent, 20-30 parts of deionized water, 30-35 parts of an etherification accelerator, 15-18 parts of a quaternary ammonium salt etherifying agent, and 0.2-0.5 parts of a pH regulator;

[0007] The preparation method of the water purifier comprises the following steps:

[0008] S1. Mix nanocellulose, alkyl methyl ester etherifying agent and deionized water, and stir to dissolve;

[0009] S2. Raise the temperature to 60-65 degrees, drop the etherification promoter, adjust the pH value of the system to 9.5-10, and react for 3-4 hours;

[0010] S3. Under stirring conditions, a quaternary ammonium salt-type etherifying agent and an etherification accelerator were added to the system, and the reaction was continued with stirring for 2 to 3 hours;

[0011] S4. Adjust the pH value to 9-9.5 with an etherification promoter, then raise the temperature to 70-75 degrees and continue the reaction for 1.5-2 hours;

[0012] S5. Cool down to 30-40 degrees, adjust the pH of the system to 6-7 with a pH regulator, and obtain a highly active nanocellulose water purifier.

[0013] Furthermore, the nanocellulose is prepared from coniferous wood fibers, the diameter of the nanocellulose is 40nm-100nm, and the solid content is 2.5-3%.

[0014] By adopting the above technical scheme, the present invention preferably selects the nanocellulose width diameter to be 40nm-100nm. When the nanocellulose diameter is less than 40nm, the fluidity of the nanocellulose deteriorates, it is inconvenient to modify and use on site, and it is impossible to prepare a modified nanocellulose water-purifying agent with a sufficient concentration; in addition, when the nanocellulose diameter is greater than 100nm, the modified nanocellulose diffuses slowly at the oil-water interface, and the water-purifying effect will be reduced; therefore, nanocellulose with a diameter of 40nm to 100nm is preferred, which is conducive to obtaining modified nanocellulose with good fluidity and good dispersion in oil and water.

[0015] Furthermore, the alkyl methyl ester etherifying agent is a mixture of methyl chloroacetate and methyl chloropropionate, and the composite mass ratio is 1:1 to 2:3.

[0016] By adopting the above technical scheme, nanocellulose is etherified and modified by using alkyl methyl ester etherifying agents, and the etherification modification conditions of alkyl methyl ester etherifying agents are studied. The modified nanocellulose obtained has a strong breaking effect on water-in-oil emulsions. At the same time, the nanocellulose is compositely etherified and modified by using two alkyl methyl ester etherifying agents with different chain lengths. The modified nanocellulose obtained has a good breaking effect on water-in-oil bubbles of different specifications.

[0017] Furthermore, the quaternary ammonium salt etherifying agent is a composite of 3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride, and the mass ratio of the two is 1:1 to 1:2.

[0018] By adopting the above technical scheme, cationic quaternary ammonium salt type side groups are introduced through etherification reaction, so that the modified nanocellulose can further obtain strong charge adsorption effect on oil-containing colloids in water, forming fine flocs that float on the surface; the nanocellulose can be modified by alkyl methyl ester and quaternization to prepare a highly active nanocellulose water purifier product.

[0019] Furthermore, the etherification promoter is a compound of 30% sodium hydroxide and 20% potassium hydroxide, and the weight ratio is 1:1 to 3:2.

[0020] Furthermore, the pH adjuster is any one of hydrochloric acid, acetic acid and sulfuric acid.

[0021] By adopting the above technical solution and using a pH adjuster to adjust the pH of the system, it can be adjusted according to the pH conditions of the platform wastewater, so that the modified nanocellulose has better applicability and better water purification performance.

[0022] Furthermore, the mass ratio of the etherification promoter in step S2 and step S3 is (8-10):(22-25).

[0023] In a second aspect, the present invention provides a highly active nanocellulose water-purifying agent, which is achieved by adopting the following technical scheme.

[0024] A highly active nanocellulose water-cleaning agent prepared by the above preparation method has a solid content greater than 10% and a bulk viscosity less than 100 cp. The agent can be used as a flocculant to treat organic industrial wastewater and as a water-cleaning agent to treat oily wastewater.

[0025] The present invention achieves the following beneficial effects.

[0026] (1) The present invention optimizes the nanocellulose width to be 40 nm to 100 nm, which is beneficial for obtaining a nanocellulose matrix with good fluidity and good dispersion in oil and water, and is also beneficial for etherification modification;

[0027] (2) Nanocellulose was etherified by using an alkyl methyl ester etherifying agent, and the etherification modification conditions of the alkyl methyl ester etherifying agent were studied. The modified nanocellulose obtained had a strong breaking effect on water-in-oil emulsions. At the same time, the nanocellulose was modified by using two alkyl methyl ester etherifying agents with different chain lengths. The modified nanocellulose obtained had a good breaking effect on water-in-oil bubbles of different sizes.

[0028] (3) The present invention introduces cationic quaternary ammonium salt side groups through etherification reaction, so that the modified nanocellulose further obtains strong charge adsorption effect on oil-containing colloids in water, forming fine flocs that float on the surface; the nanocellulose is modified by alkyl methyl ester and quaternary ammonium to prepare a highly active nanocellulose water purifier product;

[0029] (4) The present invention uses a pH regulator to adjust the pH of the system, which can be adjusted according to the pH of the platform wastewater, so that the modified nanocellulose has better applicability and better water purification performance;

[0030] (5) The modified nanocellulose prepared by the present invention has good flowability and good oil-water interface dispersion performance by controlling the width and aspect ratio of the nanocellulose, and the viscosity is less than 100cp, which is convenient for on-site injection and use;

[0031] In summary, the high-activity nanocellulose water-purifying agent prepared by the present invention has the characteristics of strong lipophilicity, fast diffusion speed, low bulk viscosity, good low-temperature resistance, rapid solubility and storage stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a diagram showing the oil-water separation performance of the highly active nanocellulose-based polymer of the present invention for oily wastewater (a diagram showing the effect of clear water after standing in a water bath for 20 minutes, from left to right are Examples 1-7). DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below through specific implementation methods.

[0034] The nanocellulose used in the embodiments of the present invention is prepared from softwood fiber and purchased from China Pulp and Paper Research Institute Co., Ltd.

[0035] Example 1

[0036] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0037] 200 g of nanocellulose, 5 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 20 g of deionized water were added into a reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 61 degrees, 8 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.5, and the reaction was continued for 3 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-cyclopentane) was slowly added in agitation. 15g of 2-hydroxypropyltrimethylammonium chloride (mixed in a mass ratio of 1:1) and 22g of an etherification promoter (mixed in a weight ratio of 1:1 with 30% sodium hydroxide and 20% potassium hydroxide) were added to a reactor, and the reaction was continued with stirring for 3 hours; the pH value was adjusted to 9.2 with the etherification promoter, and then the temperature was raised to 70 degrees and the reaction was continued for 2 hours; the temperature was slowly lowered to 30 degrees with circulating water, and the pH of the system was adjusted to 6 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 67cp and a solid content of 10.2%.

[0038] Example 2

[0039] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0040] 210 g of nanocellulose, 6 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 20 g of deionized water were added into a reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 63 degrees, 9 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.6, and the reaction was continued for 3 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropane) was slowly added in. 16g of 1,2-trimethylammonium chloride (mixed in a weight ratio of 1:1) and 23g of an etherification promoter (mixed in a weight ratio of 1:1 with 30% sodium hydroxide and 20% potassium hydroxide) were added to a reactor, and the reaction was continued with stirring for 2.5 hours; the pH value was adjusted to 9.3 with the etherification promoter, and then the temperature was raised to 72 degrees and the reaction was continued for 1.5 hours; the temperature was slowly lowered to 36 degrees with circulating water, and the pH of the system was adjusted to 6 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 72cp and a solid content of 10.4%.

[0041] Example 3

[0042] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0043] 220 g of nanocellulose, 6 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 20 g of deionized water were added to the reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 62 degrees, and 9 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.7, and the reaction was continued for 3.5 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-cyclopentane) was slowly added; 17g of 2-hydroxypropyltrimethylammonium chloride (mixed in a mass ratio of 1:1) and 24g of an etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) were added to a reactor, and the reaction was continued with stirring for 2.5 hours; the pH value was adjusted to 9.4 with the etherification promoter, and then the temperature was raised to 70 degrees and the reaction was continued for 2 hours; the temperature was slowly lowered to 30 degrees with circulating water, and the pH of the system was adjusted to 7 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 69cp and a solid content of 10.0%.

[0044] Example 4

[0045] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0046] 230 g of nanocellulose, 7 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 22 g of deionized water were added to a reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 62 degrees, and 10 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.8, and the reaction was continued for 4 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-cyclopentane) was slowly added; 18g of 2-hydroxypropyltrimethylammonium chloride (mixed in a mass ratio of 1:1) and 25g of an etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) were added to a reactor, and the reaction was continued with stirring for 3 hours; the pH value was adjusted to 9.5 with the etherification promoter, and then the temperature was raised to 73 degrees and the reaction was continued for 2 hours; the temperature was slowly lowered to 30 degrees with circulating water, and the pH of the system was adjusted to 6.5 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 65cp and a solid content of 10.3%.

[0047] Example 5

[0048] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0049] 220 g of nanocellulose, 6 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 20 g of deionized water were added to the reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 63 degrees, and 10 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.9, and the reaction was carried out for 3 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-cyclopentane) was slowly added; 17g of 2-hydroxypropyltrimethylammonium chloride (mixed in a mass ratio of 1:1) and 24g of an etherification promoter (mixed in a weight ratio of 1:1 with 30% sodium hydroxide and 20% potassium hydroxide) were added to a reactor, and the reaction was continued with stirring for 2 hours; the pH value was adjusted to 9.3 with the etherification promoter, and then the temperature was raised to 74 degrees and the reaction was continued for 1.5 hours; the temperature was slowly lowered to 34 degrees with circulating water, and the pH of the system was adjusted to 7 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 69cp and a solid content of 10.5%.

[0050] Example 6

[0051] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0052] 210 g of nanocellulose, 5 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 22 g of deionized water were added into a reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 64 degrees, 8 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 10.0, and the reaction was carried out for 4 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxy 17g of propyltrimethylammonium chloride (mixed in a mass ratio of 1:1) and 25g of an etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) were added to a reactor, and the reaction was continued with stirring for 2 hours; the pH value was adjusted to 9.3 with the etherification promoter, and then the temperature was raised to 70 degrees and the reaction was continued for 1.5 hours; the temperature was slowly lowered to 36 degrees with circulating water, and the pH of the system was adjusted to 6.5 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 66cp and a solid content of 10.3%.

[0053] Example 7

[0054] A method for preparing a highly active nanocellulose water-purifying agent comprises the following steps:

[0055] 210 g of nanocellulose, 6 g of alkyl methyl ester etherifying agent (methyl chloroacetate and methyl chloropropionate mixed in a weight ratio of 1:1) and 22 g of deionized water were added into a reactor and stirred thoroughly to dissolve; the temperature was slowly raised to 65 degrees, and 9 g of etherification promoter (30% sodium hydroxide and 20% potassium hydroxide mixed in a weight ratio of 1:1) was slowly dripped in, the pH value of the system was adjusted to 9.8, and the reaction was continued for 3 hours; while continuing to stir, the quaternary ammonium salt etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropane) was slowly added in. 18g of 1,2-trimethylammonium chloride (mixed in a weight ratio of 1:1) and 25g of an etherification promoter (mixed in a weight ratio of 1:1 with 30% sodium hydroxide and 20% potassium hydroxide) were added to a reactor, and the reaction was continued with stirring for 2.5 hours; the pH value was adjusted to 9.4 with the etherification promoter, and then the temperature was raised to 70 degrees and the reaction was continued for 1.5 hours; the temperature was slowly lowered to 38 degrees with circulating water, and the pH of the system was adjusted to 7 with acetic acid, a pH regulator, to obtain a high-activity nanocellulose water-purifying agent with a bulk viscosity of 62cp and a solid content of 10.2%.

[0056] Performance Testing

[0057] The oil-water separation performance of the highly active nanocellulose water-clearing agent prepared in Examples 1-7 of the present application was tested. The testing method was based on the industry standard SY / T 5797-1993 "Method for evaluating the performance of oil-in-water emulsion demulsifiers". The test results are shown in Tables 1 and Figure 1 .

[0058] Table 1 Oil-water separation performance of highly active nanocellulose-based polymers for oily wastewater

[0059]

[0060]

[0061] Note: A+, A, A-: clear; B+, B, B-: fair; C+, C, C-: poor

[0062] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in the field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the technical requirements.

Claims

1. A method for preparing a highly active nanocellulose water purifier, characterized in that: The water purifier comprises the following raw materials in parts by weight: 200-230 parts of nanocellulose, 5-7 parts of alkyl methyl ester etherifying agent, 20-30 parts of deionized water, 30-35 parts of etherification accelerator, 15-18 parts of quaternary ammonium salt etherifying agent, and 0.2-0.5 parts of pH regulator; The preparation method of the water purifier comprises the following steps: S1. Mix nanocellulose, alkyl methyl ester etherifying agent and deionized water, and stir to dissolve; S2. Raise the temperature to 60-65 degrees, drop the etherification promoter, adjust the pH value of the system to 9.5-10, and react for 3-4 hours; S3. Under stirring conditions, a quaternary ammonium salt-type etherifying agent and an etherification accelerator were added to the system, and the reaction was continued with stirring for 2 to 3 hours; S4. Adjust the pH value to 9-9.5 with an etherification promoter, then raise the temperature to 70-75 degrees and continue the reaction for 1.5-2 hours; S5. Cool down to 30-40 degrees, adjust the pH of the system to 6-7 with a pH regulator, and obtain a highly active nanocellulose water purifier.

2. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The nanocellulose is prepared from coniferous wood fibers, has a diameter of 40nm-100nm, and a solid content of 2.5-3%.

3. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The alkyl methyl ester etherifying agent is a mixture of methyl chloroacetate and methyl chloropropionate, and the compounding mass ratio is 1:1 to 2:

3.

4. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The quaternary ammonium salt etherifying agent is a composite of 3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride, and the mass ratio of the two is 1:1 to 1:

2.

5. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The etherification accelerator is a compound of 30% sodium hydroxide and 20% potassium hydroxide, and the weight ratio is 1:1 to 3:

2.

6. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The pH adjuster is any one of hydrochloric acid, acetic acid and sulfuric acid.

7. The method for preparing a highly active nanocellulose water-purifying agent according to claim 1, characterized in that: The mass ratio of the etherification promoter in step S2 and step S3 is (8-10):(22-25).

8. A high-activity nanocellulose water-purifying agent prepared by the preparation method according to any one of claims 1 to 7.

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