阅读说明：本技术 一种提高有机溶剂酸沉降纳米木质素稳定性的方法 (Method for improving stability of organic solvent acid-precipitated nano lignin ) 是由 徐建 吴海军 杨超华 左宗涛 顾帅令 王标 张楷 徐霞 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种提高有机溶剂酸沉降纳米木质素稳定性的方法,包括以下步骤：将有机溶剂酸沉降制备的纳米木质素从制备溶液中直接离心洗涤,洗涤后加入去离子水再次进行离心洗涤,重复多次；加入去离子水,调节纳米木质素的浓度；通过匀浆机将团聚的纳米木质素均匀分散一段时间,再利用超声波分散设备进行一段时间超声分散,最终得到高稳定性纳米木质素分散液。本发明具有操作简单、成本较低的优点,在保证纳米木质素粒子大小的同时,改善Zeta电位,极大地提高了纳米木质素粒子的稳定性,制得的高稳定性纳米木质素分散液应用广泛。(The invention discloses a method for improving the stability of organic solvent acid-precipitated nano lignin, which comprises the following steps: directly centrifugally washing the nano lignin prepared by organic solvent acid sedimentation from the preparation solution, adding deionized water after washing, centrifugally washing again, and repeating for multiple times; adding deionized water, and adjusting the concentration of the nano lignin; uniformly dispersing the agglomerated nano lignin for a period of time by a homogenizer, and performing ultrasonic dispersion for a period of time by using ultrasonic dispersion equipment to finally obtain the high-stability nano lignin dispersion liquid. The method has the advantages of simple operation and low cost, improves Zeta potential while ensuring the size of the nano lignin particles, greatly improves the stability of the nano lignin particles, and has wide application of the prepared high-stability nano lignin dispersion liquid.)

1. A method for improving the stability of organic solvent acid-precipitated nano lignin is characterized by comprising the following steps:

(1) directly centrifugally washing the nano lignin prepared by organic solvent acid sedimentation from the preparation solution, adding deionized water after washing, centrifugally washing again, and repeating for multiple times; adding deionized water, and adjusting the concentration of the nano lignin to be 0.2-0.9 mg/mL;

(2) uniformly dispersing the agglomerated nano lignin for a period of time by a homogenizer, and performing ultrasonic dispersion for a period of time by using ultrasonic dispersion equipment to finally obtain the high-stability nano lignin dispersion liquid.

2. The method for improving the stability of the organic solvent acid-settled nano lignin according to claim 1, wherein the method for preparing the nano lignin by the organic solvent acid-settled nano lignin comprises the following steps: dissolving lignin in alcohol solvent, filtering to remove impurities, adding acid into lignin solution, dialyzing, and adding acid into dialysate to obtain preparation solution containing nano lignin.

3. The method for improving the stability of organosolv acid-settled nanocignin according to claim 2, wherein: the acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and trifluoroacetic acid.

4. The method for improving the stability of organosolv acid-settled nanocignin according to claim 1, wherein: when in centrifugal washing, the centrifugation speed of each time is 18000-22000rpm, and the centrifugation time is 13-17 min.

5. The method for improving the stability of organosolv acid-settled nanocignin according to claim 1, wherein: the homogenizer uniformly disperses the agglomerated nano lignin for 15-25min at the speed of 8000-12000 rpm.

6. The method for improving the stability of organosolv acid-settled nanocignin according to claim 1, wherein: the frequency of the ultrasonic dispersion equipment is 40kHz, the power is 100w, and the ultrasonic dispersion time is 8-22 min.

Technical Field

The invention relates to the technical field of nano lignin production, in particular to a method for improving the stability of organic solvent acid-precipitated nano lignin.

Background

Among the three components of biomass, cellulose and hemicellulose which are relatively simple in structure and composition are taken as the three components, and certain progress is achieved from the research and industrialization perspectives; however, as for another component lignin having a complex three-dimensional structure, studies on its utilization are still underway. The continuous development of the nano technology provides a new way for the high-added-value utilization of the lignin, and the characteristics of larger specific surface area, better compatibility and no cytotoxicity of the nano lignin are considered. Therefore, the lignin prepared nanoparticles show good application prospects in the aspects of drug carriers, nano fillers and the like. The nano lignin prepared by acid precipitation is very easy to agglomerate due to the reasons of low surface charge, extremely short distance between particles, very large van der Waals force and the like, and meanwhile, strong hydrogen bonds are formed between the agglomerated nano lignin and are difficult to separate, so that the using effect of the nano lignin is not ideal due to the reasons.

Therefore, it is necessary to provide a method for improving the stability of the acid-precipitated nano lignin in the organic solvent, so that the stability of the nano lignin particles can be improved while the size of the nano lignin particles is ensured.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a method for improving the stability of organic solvent acid-precipitated nano lignin.

In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:

a method for improving the stability of organic solvent acid-precipitated nano lignin comprises the following steps:

(1) directly centrifugally washing the nano lignin prepared by organic solvent acid sedimentation from the preparation solution, adding deionized water after washing, centrifugally washing again, and repeating for multiple times; adding deionized water, and adjusting the concentration of the nano lignin to be 0.2-0.9 mg/mL;

(2) uniformly dispersing the agglomerated nano lignin for a period of time by a homogenizer, and performing ultrasonic dispersion for a period of time by using ultrasonic dispersion equipment to finally obtain the high-stability nano lignin dispersion liquid.

Further, as mentioned above, the method for improving the stability of the organic solvent acid-precipitated nano lignin comprises the following steps: dissolving lignin in alcohol solvent, filtering to remove impurities, adding acid into lignin solution, dialyzing, and adding acid into dialysate to obtain preparation solution containing nano lignin.

Further, in the method for improving the stability of the organic solvent acid-precipitated nano lignin, the acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and trifluoroacetic acid.

Further, in the method for improving the stability of the organic solvent acid-precipitated nano lignin, the centrifugation speed is 18000-22000rpm each time and the centrifugation time is 13-17min during the centrifugal washing.

Further, in the method for improving the stability of the organic solvent acid-precipitated nano lignin, the homogenizer uniformly disperses the agglomerated nano lignin for 15-25min at the speed of 8000-12000 rpm.

Further, in the method for improving the stability of the organic solvent acid-precipitated nano lignin, the frequency of the ultrasonic dispersion equipment is 40kHz, the power is 100w, and the ultrasonic dispersion time is 8-22 min.

The invention has the beneficial effects that:

the method of the invention has the advantages of simple operation,

the invention provides a method for improving the stability of organic solvent acid-precipitated nano lignin, which has the advantages of scientific and reasonable design, simple operation and low cost, improves Zeta potential while ensuring the size of nano lignin particles, greatly improves the stability of the nano lignin particles, and has wide application of the prepared high-stability nano lignin dispersion liquid.

Of course, it is not necessary for any one product that embodies the invention to achieve all of the above advantages simultaneously.

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.

In the invention, the method for preparing the nano lignin by organic solvent acid sedimentation comprises the following steps: dissolving lignin in alcohol solvent, filtering to remove impurities, adding acid into lignin solution, dialyzing, and adding acid into dialysate to obtain preparation solution containing nano lignin. The acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and trifluoroacetic acid.

The following embodiments are relevant to the present invention:

example 1

Centrifuging the acid-precipitated nano lignin at 20000rpm for 15min, washing with deionized water, and repeating the steps for 3 times. Deionized water is added to adjust the concentration of the nano lignin to be 0.3 mg/mL. After dispersing for 20min at 10000rpm by using a homogenizer, carrying out ultrasonic treatment for 20min by 100w, and detecting the average particle size, PDI and Zeta potential of the nano lignin by using Malvern ZS 90.

The results show that the particle size, PDI and Zeta potential of the original nano lignin are respectively 160.1nm, 0.278 and-13.7 mV, and the nano lignin after redispersion is respectively 210.3nm, 0.384 and-30.57 mV.

Example 2

Centrifuging the acid-precipitated nano lignin at 20000rpm for 15min, washing with deionized water, and repeating the steps for 3 times. Deionized water is added to adjust the concentration of the nano lignin to be 0.9 mg/mL. Dispersing for 10min at 10000rpm by using a homogenizer, then carrying out ultrasonic treatment for 10min by 100w, and detecting the average particle size, PDI and Zeta potential of the nano lignin by using Malvern ZS 90.

The results show that the particle size, PDI and Zeta potential of the original nano lignin are respectively 160.1nm, 0.278 and-13.7 mV, and the nano lignin after redispersion is respectively 537.9nm, 0.592 and-30.21 mV.

Example 3

Centrifuging the acid-precipitated nano lignin at 20000rpm for 15min, washing with deionized water, and repeating the steps for 3 times. Deionized water is added to adjust the concentration of the nano lignin to be 0.6 mg/mL. Dispersing for 20min at 10000rpm by using a homogenizer, then carrying out ultrasonic treatment for 10min by 100w, and detecting the average particle size, PDI and Zeta potential of the nano lignin by using Malvern ZS 90.

The results show that the particle size, PDI and Zeta potential of the original nano lignin are respectively 160.1nm, 0.278 and-13.7 mV, and the nano lignin after redispersion is respectively 425.6nm, 0.532 and-30.45 mV.

Example 4

Centrifuging the acid-precipitated nano lignin at 20000rpm for 15min, washing with deionized water, and repeating the steps for 3 times. Deionized water is added to adjust the concentration of the nano lignin to be 0.2 mg/mL. After dispersing for 20min at 10000rpm by using a homogenizer, carrying out ultrasonic treatment for 20min by 100w, and detecting the average particle size, PDI and Zeta potential of the nano lignin by using Malvern ZS 90.

The results show that the particle size, PDI and Zeta potential of the original nano lignin are respectively 160.1nm, 0.278 and-13.7 mV, and the nano lignin after redispersion is respectively 280.0nm, 0.453 and-30.21 mV.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.