阅读说明：本技术 一种利用甘草地上部分提取液绿色合成纳米氧化锌的方法及其应用 (Method for green synthesis of nano zinc oxide by using licorice aerial part extract and application thereof ) 是由 宋吉明 董庄庄 方晶 于 2021-01-09 设计创作，主要内容包括：本发明公开了一种利用甘草地上部分提取液绿色合成纳米氧化锌的方法及其应用。将甘草地上部分干燥、粉碎后,经加热回流提取、过滤、浓缩,得到甘草地上部分提取液；以甘草地上部分提取液和锌源配位得到前驱体、经煅烧绿色合成纳米氧化锌。结果表明以甘草地上部分提取液为生物模板剂制备的纳米氧化锌为六方纤锌矿结构,结晶度良好,晶粒平均尺寸约58.8 nm。以氙灯为光源,在60 min内合成纳米氧化锌对亚甲基蓝(MB)染料降解率可达到98.6%。该制备方法简单、反应条件温和、不需添加额外的化学试剂,且稳定性良好,具有很好的光催化性能。(The invention discloses a method for green synthesis of nano zinc oxide by using an aerial part extract of liquorice and application thereof. Drying and crushing the overground part of the liquorice, heating, refluxing, extracting, filtering and concentrating to obtain an overground part extracting solution of the liquorice; the extraction liquid of the overground part of the liquorice is coordinated with a zinc source to obtain a precursor, and the precursor is calcined to synthesize the nano zinc oxide in a green way. The result shows that the nano zinc oxide prepared by taking the extract of the overground part of the liquorice as the biological template agent has a hexagonal wurtzite structure, good crystallinity and the average size of crystal grains of about 58.8 nm. The degradation rate of the nano zinc oxide to Methylene Blue (MB) dye can reach 98.6 percent within 60 min by taking a xenon lamp as a light source. The preparation method is simple, the reaction condition is mild, no additional chemical reagent is needed to be added, the stability is good, and the photocatalysis performance is good.)

1. A method for green synthesis of nano zinc oxide by using an aerial part extract of liquorice and application thereof are characterized by comprising the following steps:

airing and crushing the aerial part of liquorice, weighing 10-100 g of powder in 10-20 times of distilled water, performing reflux extraction for 1-3 hours at the temperature of 65-85 ℃, performing suction filtration under reduced pressure, separating filtrate and filter residue, repeatedly extracting the filter residue, combining supernate, and performing reduced pressure concentration to 1/3 of the original volume to obtain an aerial part extract of liquorice for later use; heating 20-80 ml of aerial part extract of Glycyrrhrizae radix at 60-80 deg.C under magnetic stirring, and adding zinc nitrate hexahydrate to obtain Zn²⁺The concentration is 0.4-0.8 mmol/L, the mixture is subjected to rotary evaporation to form an extract, the extract is dried in a forced air drying oven at the temperature of 60-80 ℃ overnight to obtain a yellow precursor, the precursor is transferred to a ceramic crucible, and the precursor is taken out after being subjected to heat preservation in a muffle furnace at the temperature of 400 ℃ for 2-4 hours to obtain white nano zinc oxide powder, and the characterization shows that the nano zinc oxide prepared by taking the overground part extract of liquorice as a biological template has a hexagonal wurtzite structure, good crystallinity and the average size of crystal grains is about 58.8 nm.

2. The application of the nano zinc oxide synthesized by the method in the claim 1 in photocatalytic degradation of methylene blue dye is characterized in that a 300W xenon lamp is used as a light source, 50 mg ZnO nanoparticles are used as a photocatalyst, 50-200 ml of 15 mg/L methylene blue dye aqueous solution is degraded, and the mixed solution is placed in a dark room for 30-60 min before irradiation of the xenon lamp to achieve adsorption-desorption balance; and then carrying out catalytic degradation under a xenon lamp light source, taking out 3 ml of mixed solution every 10 min, carrying out centrifugal separation, taking supernatant, and detecting the absorbance at 664 nm by using an ultraviolet spectrophotometer to monitor the dye concentration, wherein the result shows that the degradation rate of the methylene blue dye by synthesizing the nano zinc oxide can reach 98.6% within 60 min.

Technical Field

The invention belongs to the technical field of nano material preparation, and particularly relates to a method for green synthesis of nano zinc oxide by utilizing an aerial part extract of liquorice and application thereof.

Background

The nano material has important significance in scientific development and application due to the special functions and effects thereof, and opens up a new research field for the development of new materials. The synthesis of nano materials mostly adopts physical, chemical and biological synthesis methods, wherein the chemical synthesis route is widely accepted, and a plurality of inorganic and organic reducing agents are used, but the method has the defects of high cost, high toxicity, difficult separation, high danger and the like. Over the past decade, many researchers have proposed the use of natural biomass or agricultural waste, such as plant leaf extracts, flowers, fruits, vegetables, bacteria, fungi, algae, etc., as green synthetic nanomaterials. Compared with the traditional physical and chemical methods, the green synthesis process for the nano material has the advantages of mild reaction conditions, small toxicity of used chemical substances, simple separation, low synthesis cost and the like.

ZnO is a novel multifunctional semiconductor material, has strong catalytic activity, is green and environment-friendly, and can be repeatedly used. In the patent (Xulegimine and the like, a preparation method of zinc oxide, CN 2020107008620), zinc oxide with different shapes is obtained by controlling the addition amounts of zinc acetate dihydrate and ammonia water through a hydrothermal method, but the method is still a chemical synthesis route and has the defects of high cost, high toxicity and the like; in the literature (Lufan, etc., nano zinc oxide prepared by vine tea flavone in green and the antioxidation and antibacterial properties thereof, fine chemical engineering, 2020, 37(09): 1793-1798), nano zinc oxide is prepared by the vine tea flavone by using a solution combustion method, and the nano zinc oxide is subjected to antibacterial and antioxidant researches, and the results show that the ZnO prepared in green has good antioxidant activity and bacteriostatic ability. According to literature investigation, no patent related to green synthesis of nano zinc oxide from an extract of the aerial part of liquorice is reported at present. The method takes the extract of the aerial part of the liquorice as a template, synthesizes nano zinc oxide nanoparticles in a green way by coordination and calcination, performs a series of characterization on a synthetic sample, and determines the capability of the synthetic sample for degrading organic pollutants by photocatalysis.

Disclosure of Invention

The invention aims to provide a method for green synthesis of nano-zinc oxide by using an aerial part extract of liquorice and application thereof.

The invention comprises the following steps:

1. preparation of licorice aerial part extract solution

Cutting the overground part of the liquorice into small sections, crushing the small sections by using a crusher, sieving the small sections by using a sieve of 80 meshes, weighing 10-100 g of overground part powder of the liquorice, adding 10-20 times of distilled water, extracting the powder for 1-3 hours at the temperature of 65-85 ℃, carrying out suction filtration under reduced pressure, separating filtrate and filter residue, repeatedly extracting the filter residue for 1-3 times, combining supernate, and carrying out rotary evaporation and concentration to 1/3 of the original volume to obtain the overground part extract of the liquorice for later use.

2. Green preparation of nano zinc oxide from aerial part extract of liquorice

Heating 20-80 ml of radix Glycyrrhizae aerial part extractive solution at 60-80 deg.C under magnetic stirring, and adding zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂O) to Zn²⁺The concentration is 0.4-0.8 mmol/L, and the mixture is steamed in a rotating way to form an extract. And drying the sample in a forced air drying oven at the temperature of 60-80 ℃ overnight to obtain a yellow precursor. And transferring the precursor into a ceramic crucible, preserving the heat of the ceramic crucible in a muffle furnace at 400 ℃ for 2-4 h, and taking out the ceramic crucible to obtain white powder.

Photocatalytic degradation of Methylene Blue (MB) dyes by ZnO nanoparticles

Under the irradiation of a xenon lamp light source (300W), the photocatalytic degradation performance of the green synthesized ZnO nanoparticles on the MB dye is evaluated. A system consisting of 50 mg of ZnO nanoparticles and 50-200 ml of MB dye (15 mg/L) is carried out in a glass container, before irradiation, the ZnO nanoparticles are reacted in a dark room for 30-60 min to reach adsorption-desorption equilibrium, then catalytic degradation is carried out under a xenon lamp light source, 3 ml of mixed solution is taken out every 10 min, centrifugal separation is carried out, and supernatant is taken out to detect the absorbance at 664 nm through an ultraviolet spectrophotometer to monitor the dye concentration.

Description of the drawings:

FIG. 1 is an X-ray diffraction (XRD) spectrum of ZnO nanoparticles prepared in example 2;

FIG. 2 is a Fourier Infrared (FTIR) spectrum of ZnO nanoparticles prepared in example 2; (ii) a

FIG. 3 is a Thermogravimetric (TG) curve of the ZnO nanoparticle precursor prepared in example 2;

FIG. 4 is a Transmission Electron Microscope (TEM) picture of ZnO nanoparticles prepared in example 2;

FIG. 5 is a graph of UV absorption spectra of photocatalytic degradation of Methylene Blue (MB) dye by ZnO nanoparticles in example 3 at different times;

FIG. 6 shows the MB dye degradation rate of photocatalytic degradation of ZnO nanoparticles in example 3;

the specific implementation mode is as follows:

the invention is illustrated in detail below with reference to the examples:

example 1: preparation of aerial part extract of licorice

Cutting the aerial parts of the liquorice into small sections, crushing the small sections by using a crusher, sieving the small sections by using a sieve of 80 meshes, accurately weighing 10 g of aerial parts of the liquorice powder, adding 15 times of water solution, extracting the mixture for 2 hours at the temperature of 85 ℃, carrying out vacuum filtration to separate filtrate and filter residue, repeatedly extracting the filter residue for 3 times, combining supernate, and carrying out vacuum concentration to l/3 of the original volume to obtain the aerial parts of the liquorice extract for later use.

Example 2: green preparation of zinc oxide nanoparticles from aerial part extract of liquorice

Heating 50 ml radix Glycyrrhizae aerial part extractive solution under magnetic stirring at 80 deg.C, adding zinc nitrate hexahydrate (Zn (NO)₃)₂·6H₂O) to Zn²⁺And (3) performing rotary evaporation until the concentration is 0.5 mmol/L to form an extract, and drying the sample in a forced air drying oven at the temperature of 80 ℃ overnight to obtain a yellow precursor. And then transferring the precursor into a ceramic crucible, preserving the heat of the ceramic crucible in a muffle furnace at 400 ℃ for 3 h, and taking out the ceramic crucible to obtain white nano zinc oxide powder.

Example 3: photocatalytic degradation of MB dye by ZnO particles

Under the irradiation of a xenon lamp light source (300W), the photocatalytic degradation performance of the green synthesized ZnO nanoparticles on the MB dye is evaluated. All experiments were carried out in a glass vessel consisting of 50 mg ZnO nanoparticles and 100 ml MB dye (15 mg/L), after adsorption-desorption equilibrium was reached 30 min in the dark before irradiation, catalytic degradation was carried out under a xenon lamp light source, 3 ml of mixed solution was taken out every 10 min, centrifuged and the dye concentration was monitored by detecting the absorbance at 664 nm with an ultraviolet spectrophotometer.

The synthesized nano zinc oxide particles are characterized, as shown in figure 1, the crystal structure of the synthesized ZnO nanoparticles is determined by XRD, and the result shows that the diffraction peaks of the material correspond to the peak positions of ZnO in the hexagonal wurtzite structure of the standard card, the peak shapes are sharp, no impurity peak appears, and the prepared zinc oxide has good crystallinity and high purity. As shown in fig. 2, the infrared characteristics of ZnO nanoparticles are as follows: 3409 cm^-1The peak may be due to stretching of-OH groups in biological activities such as flavones, phenols, etc.; 1382 cm^-1The peak is ascribed to the bending vibration peak of the powder surface bridging hydroxyl group and is 600 cm^-1To 400 cm^-1The energy band of the region is attributable to the stretching vibration frequency of the metal oxygen, namely 472 cm^-1The peak is the stretching vibration peak of Zn-O, which shows that functional groups such as ketone, carboxylic acid, polyalcohol and terpenoid play a main role in the biological reduction reaction. As shown in FIG. 3, thermogravimetric analysis of the precursor shows that the precursor is a main weightless zone at 65-380 ℃, and the curve at this temperature interval first drops rapidly and then drops slowly and becomes gentle after 320 ℃. The process is mainly caused by the decomposition of residual moisture and OH & lt- & gt on the surface of the intermediate body and the loss of part of crystal water, and the weight loss rate is 69%. The intermediate has basically decomposed completely at about 380 deg.c, and the temperature for calcining to prepare zinc oxide may be over 380 deg.c and 400 deg.c. As shown in fig. 4, the hexagonal wurtzite structure of the ZnO nanoparticles can be visually observed by TEM, which is consistent with the XRD analysis result, the average diameter is about 58.8 nm, and the particle size distribution is uniform.

The evaluation of the effect of the ZnO nanoparticles on degrading MB can be seen in fig. 5-6, that MB solution is degraded quickly within 60 min, and the degradation rate reaches 98.6% within 60 min, which shows that the green synthesized nano zinc oxide particles have good photocatalytic performance.