阅读说明：本技术 一种银杏叶改性双金属去除污水厂出水中抗生素抗性基因的方法 (Method for removing antibiotic resistance genes in effluent of sewage plant by using modified double metals of ginkgo leaves ) 是由 高景峰 段婉君 邬志龙 张文治 王雨薇 于 2019-11-21 设计创作，主要内容包括：一种银杏叶改性双金属去除污水厂二级出水中抗生素抗性基因的方法,属于分子生物学领域。室温条件下,以银杏叶提取液作为分散剂与稳定剂,钴作为金属催化剂,通过化学还原法制备了表面修饰型和负载型银杏叶改性的铁钴双金属颗粒,用于抗生素抗性基因的去除。同时改变合成用量,提高银杏叶改性型铁钴双金属颗粒去除抗生素抗性基因能力(钴负载量为0～10％；银杏叶改性型铁钴双金属颗粒的投加浓度为0.84～1.68g/L)。本发明利用银杏叶改性型铁钴双金属颗粒去除抗生素抗性基因,方法简单快捷,绿色环保,能在短时间内达到去除抗生素抗性基因的目的,并极大的提高了改性铁的利用能力。(A method for removing antibiotic resistance genes in secondary effluent of a sewage plant by using modified bimetal ginkgo leaves belongs to the field of molecular biology. At room temperature, ginkgo leaf extract is used as a dispersant and a stabilizer, cobalt is used as a metal catalyst, and surface-modified and supported ginkgo leaf modified iron-cobalt bimetallic particles are prepared by a chemical reduction method and are used for removing antibiotic resistance genes. Meanwhile, the synthetic dosage is changed, and the capability of the ginkgo leaf modified iron-cobalt bimetallic particles for removing antibiotic resistance genes is improved (the cobalt loading is 0-10%; and the adding concentration of the ginkgo leaf modified iron-cobalt bimetallic particles is 0.84-1.68 g/L). The method for removing the antibiotic resistance genes by utilizing the ginkgo leaf modified iron-cobalt bimetallic particles is simple, rapid, green and environment-friendly, can achieve the purpose of removing the antibiotic resistance genes in a short time, and greatly improves the utilization capacity of the modified iron.)

1. A method for removing antibiotic resistance genes in secondary effluent of a sewage plant by using ginkgo leaf modified metal nanoparticles is characterized by comprising the following steps:

the method comprises the following steps: cleaning ginkgo leaf modified metal nano particles with acetone, and then cleaning with deionized water for three times;

step two: adding the ginkgo leaf modified metal nanoparticles into secondary effluent of a sewage treatment plant at room temperature, stirring or/and oscillating for no more than 10min, filtering and separating, and filtering the water phase of the whole system to remove antibiotic resistance genes in the secondary effluent.

2. The method for removing antibiotic resistance genes from secondary effluent of a sewage plant according to claim 1, wherein the particles comprise nanoscale zero-valent iron particles, nanoscale iron-cobalt particles, ginkgo leaf-modified nanoscale zero-valent iron particles, and apricot leaf-modified iron-cobalt bimetallic particles.

3. The method for removing antibiotic resistance genes from secondary effluent of a sewage plant according to claim 2, wherein the patent percentage content of cobalt in the metal nanoparticles is 0-10%.

4. The method for removing antibiotic resistance genes from secondary effluent of a sewage plant according to claim 1, wherein the initial pH of the secondary effluent is 5-9.

5. The method for removing antibiotic resistance genes from secondary effluent of a sewage plant as claimed in claim 1, wherein the primary control raw water dissolved oxygen of the secondary effluent is 0.35-8.94 mg/L.

6. The method for removing antibiotic resistance genes from secondary effluent of a sewage plant according to claim 1, wherein the concentration of the ginkgo biloba leaf modified metal nanoparticles in the secondary effluent is 0.84-1.68 g/L.

7. According to claim 1The method for removing the antibiotic resistance genes in the secondary effluent of the sewage plant by using the ginkgo leaf modified metal nanoparticles is characterized in that the initial concentration of the antibiotic resistance genes in the secondary effluent is 2.21 multiplied by 10²-2.54×10⁸copies/mL。

Technical Field

The invention belongs to the field of nano materials, wastewater treatment and molecular biology, and particularly relates to a method for removing antibiotic resistance genes in secondary effluent of a sewage plant by using ginkgo leaf modified iron-cobalt bimetallic particles.

Background

Antibiotic resistance genes can be encoded in bacterial chromosomes or extrachromosomal plasmids, triggering the biochemical defense mechanisms of the antibiotic resistance genes. This mechanism allows the bacteria to survive in the presence of the corresponding antibiotic compounds, which can seriously impair the efficacy of the antibiotic and pose a threat to public health. Antibiotic resistance genes are considered an emerging environmental pollutant. In addition, sewage treatment plants have also attracted considerable attention as one of the major "hot spots" for the diffusion of antibiotic resistance into the environment. Meanwhile, sewage treatment plants are one of the major sites for inhibiting the spread of antibiotic resistance genes. Therefore, controlling antibiotic resistance genes in sewage treatment plants is a new challenge to cope with drug resistance on a global scale.

Common disinfection technologies in sewage treatment plants mainly include chlorination, ultraviolet treatment and ozone oxidation. Chlorination disinfection is a disinfection method for inactivating microorganisms. However, chlorine can form various disinfection byproducts that are more toxic than the parent compound. Compared with chlorination disinfection, ultraviolet disinfection does not produce disinfection by-products. However, GiovannaFerro et al analyzed the potential of the UV/hydrogen peroxide process for the removal of antibiotic resistance genes. The results showed that the bla TEM gene expression increased to 3.7X 10 after 240min treatment³copies/mL, removal rate of qnr S gene in original sample (5.1X 10)⁴copies/mL) and final sample (4.3X 10)⁴copies/mL) without significant change. Yao et al, using ozone oxidation to resolve sulfonamide resistance gene sul 1 and tetracycline resistance gene tet G of secondary effluent from a sewage treatment plant, found that the reduction effect of both antibiotic resistance genes increases with the increase of ozone dosage, and when the ozone concentration increases from 27mg/L to 177.6mg/L, the antibiotic resistance genes increase from 0.5log and 0.2log to 3.2log and 2.5log, respectively, so to achieve ideal removal effect, a large amount of ozone needs to be consumed. In sum, these methods may not be sufficient to successfully remove antibiotic resistance genes (bacteria and the like are antibiotic resistant)Antibody gene produced under the conditions). Therefore, in order to effectively remove antibiotic resistance genes from secondary effluent of sewage treatment plants, a new sterilization method needs to be established.

The nano zero-valent iron of 5g/L can obviously reduce the abundance of tetracycline resistance genes and int I1 in a system in a high-temperature anaerobic digestion system of sludge; after the nano zero-valent iron is added into an anaerobic digestion system of pig manure, the reduction of antibiotic resistance genes is improved by 33.3 percent. Therefore, the nano zero-valent iron has a certain reduction effect on the antibiotic resistance gene. However, studies on the influence of nano-iron-based metals on the abundance of antibiotic resistance genes in secondary treatment effluent are rarely reported. The nano-iron-based particles are particles taking nano zero-valent iron as a main existing form, and specifically comprise nano zero-valent iron-based bimetallic particles, nano zero-valent iron modified or loaded by a certain method and iron-based bimetallic particles. Robert W.Gillham et al pioneered the use of nano zero-valent iron for treating chlorinated hydrocarbons in 1994, which raised the hot trend of nano-iron-based particle research worldwide, and the heat and footsteps of researchers to research nano-iron-based particles for repairing pollutants in the environment have been continued for more than twenty years, and there is no sign of slowing down. Although bimetallic particles are effective in removing contaminants, they lack stability, primarily due to the high surface energy and magnetic properties of the bimetallic particles themselves, and nanoscale particles are highly susceptible to agglomeration into micron-sized or larger particles. The agglomeration of the particles reduces the mobility and specific surface area of the particles, the contact area with pollutants is reduced, and the bimetallic particles are easy to react with water or oxygen to passivate the surfaces of the particles, thereby further reducing the reaction activity. The modified nano iron-based particles can inhibit the agglomeration among the particles and the passivation of the surfaces of the particles to a certain extent, and more stable particles are prepared to replace non-modified nano iron-based metal particles.

Ginkgo biloba is one of the oldest plants on earth, and contains a variety of flavones (free flavones and flavonoid glycosides), terpene lactones, phenolic acids and procyanidins as main ingredients. The ginkgo leaves belong to agricultural and forestry wastes, which are renewable, pollution-free and low-cost materials and accord with the concept of treating wastes with processes of wastes against one another. Most of the substances are neutral, and can provide steric hindrance effect and inhibit the agglomeration of particles when covering the surfaces of the particles. Researches by high peaks and the like find that when a target pollutant is active brilliant blue KN-R, the ginkgo leaf modified iron-cobalt bimetallic particles can completely remove the active brilliant blue KN-R with the initial concentration of 900mg/L within 5.5 min. The gao Jing Feng et al also performed batch tests to study the removal of triclosan; the result shows that after the reaction is carried out for 5min, the removal effect of the ginkgo leaf modified iron-cobalt bimetallic particles on the triclosan is improved by 72.4 percent compared with that of the unmodified iron-cobalt bimetallic particles. However, the reduction capability of folium ginkgo modified iron-cobalt bimetallic particles on genotype pollutants has not been studied.

Disclosure of Invention

Aiming at the problems, the invention provides a method for removing antibiotic resistance genes in secondary effluent of a sewage plant by using ginkgo leaf modified iron-cobalt bimetallic particles. The method can rapidly and environmentally remove the antibiotic resistance genes in the secondary effluent, reduce the antibiotic resistance propagation risk and is beneficial to the resource utilization of the reclaimed water.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for removing antibiotic resistance genes in secondary effluent of a sewage plant by using ginkgo leaf modified metal nanoparticles comprises the following steps:

the method comprises the following steps: cleaning ginkgo leaf modified metal nano particles with acetone, and then cleaning with deionized water for three times;

step two: adding the ginkgo leaf modified metal nanoparticles into secondary effluent of a sewage treatment plant at room temperature, stirring or/and oscillating for no more than 10min, filtering and separating, and filtering the water phase of the whole system to remove antibiotic resistance genes in the secondary effluent.

Wherein the particles comprise nano zero-valent iron particles, nano iron-cobalt particles, ginkgo leaf modified nano zero-valent iron particles and apricot leaf modified iron-cobalt bimetallic particles.

Wherein the content of cobalt in the metal nano-particles is 0-10%.

Wherein the initial pH value of the secondary effluent is 5-9.

Wherein the initial control of the dissolved oxygen of the raw water of the secondary effluent is 0.35-8.94 mg/L.

Wherein the concentration of the ginkgo leaf modified metal nano particles in the secondary effluent is 0.84-1.68 g/L.

Wherein the initial concentration of the antibiotic resistance gene in the secondary effluent is 2.21X 10²-2.54×10⁸copies/mL。

The preparation method of the ginkgo leaf modified metal nano-particles comprises the following steps:

(1) washing dust impurities on the ginkgo leaves with deionized water, and drying at 105 ℃ for 24 hours preferably;

(2) pulverizing dried folium Ginkgo, sieving, preferably selecting folium Ginkgo powder with particle diameter below 300 μm;

(3) soaking folium Ginkgo powder in anhydrous methanol for ultrasonic treatment, preferably soaking folium Ginkgo powder in anhydrous methanol at a ratio of 20-60g/L for ultrasonic treatment for 1 hr;

(4) filtering folium Ginkgo powder methanol solution to obtain filtrate as folium Ginkgo extractive solution; vacuum filtering with 0.45 μm organic filter membrane;

(5) mixing the ginkgo leaf extract with a ferrous sulfate solution at room temperature to obtain an iron salt-ginkgo leaf extract mixed solution; preferably, the mixture is shaken in a constant-temperature water bath shaker for 5min at the rotation speed of 210-250rpm and the temperature of 25 ℃.

(6) Adding a potassium borohydride solution into a mixed solution of iron salt and a ginkgo leaf extracting solution at room temperature to react to obtain a suspension of ginkgo leaf modified nano-iron particles, oscillating while adding, bubbling the solution immediately to generate a black solid in the system, and standing after the potassium borohydride solution is added until the system does not bubble any more.

(7) Mixing the cobalt chloride solution and the ginkgo leaf modified nano-iron suspension for reaction to generate ginkgo leaf modified nano-iron-cobalt bimetallic particles; placing the mixture in a constant-temperature water bath shaking table to oscillate for 20min at the rotating speed of 210-250rpm and the temperature of 25 ℃.

(8) Separating out folium Ginkgo modified nanometer iron cobalt bimetallic particles by magnetic separation, washing with deionized water and acetone, and storing the particles in acetone.

The preparation and preservation method of the non-modified nano-Fe-Co bimetallic particles is similar to the steps except that the ginkgo leaf extract is not introduced.

The ultrasonic power of the invention is 60-100W, and the temperature is 20-40 ℃.

The mass ratio of the ginkgo leaf powder to the ferrous sulfate is 0-1.4987 and is not 0; the mass ratio of the potassium borohydride ferrous sulfate is 0.3880-0.7761; the mass ratio of folium Ginkgo powder to cobalt chloride is 0-1990.8553, and is not 0.

The invention has the advantages and beneficial effects that:

(1) the method for removing the antibiotic resistance genes in the secondary effluent of the sewage plant based on the ginkgo leaf modified iron-cobalt bimetallic particles can effectively remove the antibiotic resistance genes in the secondary effluent.

(2) The antibiotic resistance genes are removed by utilizing the ginkgo leaf modified iron-cobalt bimetallic particles, and the metal particles can be recovered in a magnetic separation mode to prevent secondary pollution.

(3) The whole process is simple to operate, convenient and fast, and has a profound application prospect.

Drawings

FIG. 1 is a comparison of the effect of different nanoparticles in example 1 on the removal of antibiotic resistance genes from secondary effluent of a sewage plant;

FIG. 2 is a diagram illustrating the removal of antibiotic resistance genes from secondary effluent of a sewage plant by ginkgo leaf-modified Fe-Co bimetallic particles under different cobalt loadings in example 2;

FIG. 3 is a graph showing the removal of antibiotic resistance genes from secondary effluent of a sewage plant by ginkgo leaf-modified Fe-Co bimetallic particles at different initial pH values in example 3;

FIG. 4 shows the removal of antibiotic resistance genes from secondary effluent of a sewage plant by ginkgo leaf-modified Fe-Co bimetallic particles at different initial dissolved oxygen values in example 4;

FIG. 5 shows the removal of antibiotic resistance genes from the secondary effluent of a sewage plant in example 5 at different dosages of modified iron-cobalt bimetallic particles.

Detailed description of the preferred embodiments

The present invention will be further described with reference to the following specific examples, but the present invention is not limited to these examples.