阅读说明：本技术 一种新型二氧化铈、制备方法及应用 (Novel cerium dioxide, preparation method and application ) 是由 赵朴素 张莉莉 朱凤霞 殷竟洲 宋洁 阚卫秋 孙小军 安礼涛 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种新型二氧化铈、制备方法及应用。在制备过程中,用超声波处理一段时间,得到二氧化铈,制备方法,包括以下步骤：S1将硝酸铈溶解在水中,再加入镁粉,超声波处理一段时间,反应得到二氧化铈沉淀物；S2离心分离出二氧化铈沉淀物；S3烘干,得到淡黄色二氧化铈粉末。本发明制备方法简单易操作,不使用大型设备,无需高温处理；制备的二氧化铈对四环素类兽药废水的光催化降解效率高,相比商业二氧化铈来说,其降解能力提升3-5倍。(The invention discloses novel cerium dioxide, a preparation method and application thereof. In the preparation process, the cerium dioxide is obtained by treating the cerium dioxide for a period of time by ultrasonic waves, and the preparation method comprises the following steps: s1, dissolving cerium nitrate in water, adding magnesium powder, performing ultrasonic treatment for a period of time, and reacting to obtain cerium dioxide precipitate; s2, centrifugally separating out cerium dioxide precipitate; s3 drying to obtain light yellow cerium dioxide powder. The preparation method is simple and easy to operate, does not use large-scale equipment, and does not need high-temperature treatment; the prepared cerium dioxide has high photocatalytic degradation efficiency on tetracycline veterinary drug wastewater, and compared with commercial cerium dioxide, the degradation capacity of the prepared cerium dioxide is improved by 3-5 times.)

1. The novel cerium dioxide is characterized in that in the preparation process, the cerium dioxide is obtained after ultrasonic treatment for a period of time.

2. The method for preparing novel cerium oxide according to claim 1, comprising the steps of:

s1, dissolving cerium nitrate in water, adding magnesium powder, performing ultrasonic treatment for a period of time, and reacting to obtain cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 drying to obtain light yellow cerium dioxide powder.

3. The method for preparing novel cerium oxide according to claim 2, wherein in S1, the mass ratio of cerium nitrate to magnesium is 1: 1.

4. the method for preparing novel cerium oxide according to claim 3, wherein in S1, the ultrasonic power is 80-130W and the treatment time is 6-10 h.

5. The method for preparing novel cerium oxide according to claim 4, wherein the drying temperature is 60-75 ℃ and the treatment time is 4-6h in S3.

6. The method for preparing novel cerium oxide according to claim 5, comprising the steps of:

s1, dissolving 4mmol of cerium nitrate in 60mL of water, adding 4mmol of magnesium powder, treating for 2h by using 100W of ultrasonic waves, and reacting to obtain a cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3, drying at 60-75 ℃ for 4-6h to obtain light yellow cerium dioxide powder.

7. The application of the novel cerium dioxide according to claim 1, wherein the cerium dioxide is used as a catalyst for photocatalytic degradation of tetracycline veterinary drug wastewater.

Technical Field

The invention relates to the technical field of cerium dioxide preparation, in particular to novel cerium dioxide, a preparation method and application thereof in tetracycline veterinary drug wastewater treatment.

Background

Antibiotics have been detected in many areas of the world in recent years, and their types have been on the increasing trend, the ecological risks of antibiotics have attracted much attention, Tetracycline (TC) is a typical antibiotic, and is widely used in pharmaceuticals and feed additives due to its ability to treat bacterial diseases, and is ranked second in antibiotic production and use. However, only a small part of tetracycline is absorbed and metabolized by human or animals, and the rest exists in the environment as excrement or per se, which poses serious threat to the ecosystem, so that the redundant tetracycline is removed, and the environment is protected. Research shows that the semiconductor photocatalyst can utilize solar energy to completely degrade tetracycline, has no secondary pollution and can be used for a plurality of times in a long-acting manner. Therefore, the search for efficient semiconductor photocatalysts is the key to solving the environmental problem caused by tetracycline pollution.

Cerium oxide is attracting attention due to its non-toxicity, simple preparation method, high oxygen storage capacity, stable chemical properties, and the like. Cerium is the most abundant element in rare earth elements, so the source of cerium dioxide is very abundant. Compared with the traditional catalyst titanium dioxide light, the cerium dioxide has more active sites due to the characteristic of easy oxidation and reduction, and is beneficial to improving the activity of the photocatalytic reaction.

For commercial cerium oxide on the market, the degradation efficiency is not satisfactory when it is used for degrading tetracycline, and for this reason, we propose a novel method for preparing cerium oxide to solve the above problems.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the existing defects and provide a novel cerium dioxide, a preparation method and application, in the process of preparing the cerium dioxide, ultrasonic treatment is carried out for a period of time, and the degradation efficiency of the prepared cerium dioxide is improved by several times compared with that of the commercially applied cerium dioxide when tetracycline is degraded by photocatalysis, so that the problems in the background technology can be effectively solved.

In order to achieve the purpose, the invention provides the following technical scheme: a new type of cerium dioxide is prepared by subjecting cerium dioxide to ultrasonic treatment for a certain period of time during the preparation process to obtain ultrasonic-treated cerium dioxide.

A preparation method of novel cerium dioxide comprises the following steps:

s1, dissolving cerium nitrate in water, adding magnesium powder, performing ultrasonic treatment for a period of time, and reacting to obtain cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 drying to obtain light yellow cerium dioxide powder.

Further, in S1, the mass ratio of cerium nitrate to magnesium is 1: 1.

furthermore, in S1, the ultrasonic power is 80-130W, and the treatment time is 6-10 h.

Furthermore, in S3, the drying temperature is 60-75 ℃, and the processing time is 4-6 h.

Further, a preparation method of the novel cerium dioxide comprises the following steps:

s1, dissolving 4mmol of cerium nitrate in 60mL of water, adding 4mmol of magnesium powder, treating for 6h by using 100W of ultrasonic waves, and reacting to obtain a cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 oven drying, and treating at 60 deg.C for 6h to obtain light yellow cerium dioxide powder.

The application of the novel cerium dioxide serving as a catalyst is applied to photocatalytic degradation of tetracycline wastewater.

The catalysis principle of the semiconductor photocatalyst is as follows:

light can excite electrons in the semiconductor, and the electrons are excited from the valence band to the conduction band to generate photoproduction electrons, and corresponding photoproduction holes are generated in the valence band, and the electrons and the holes are respectively diffused to the surface of the semiconductor and react with different reaction objects on the surface. The photogenerated electrons have reducibility and the holes have oxidability, and the two types of photogenerated electrons and holes can be respectively applied to different fields.

Catalytic principle of ceria:

the cerium dioxide is excited by photons with energy larger than or equal to the forbidden bandwidth under the irradiation of light to generate photo-generated electrons (e)^-) Excited by light into the conduction band of the semiconductor, leaving a corresponding hole (h) in the valence band⁺) (ii) a Photo-generated electrons (e)^-) And a cavity (h)⁺) The cerium dioxide nano particles are compounded or migrated to the surface of the material in the interior; photo-generated electrons (e)^-) And a cavity (h)⁺) Reach the surface of the cerium dioxide particles and interact with the substances adsorbed on the surface of the cerium dioxide particles or substances in a solvent, namely, oxidation-reduction reaction occurs, so that some free radicals (OH, O) with strong oxidizing property are generated₂ ^-) And a substance (H) having a certain oxidizing ability₂O₂) (ii) a The generated free radicals and oxidizing substances with strong oxidizing property have sufficient action with degraded pollutants to oxidize or mineralize the free radicals and the oxidizing substances into inorganic products and H₂O。

Compared with the prior art, the invention has the beneficial effects that: the novel cerium oxide has the following advantages:

the preparation method is simple and easy to operate, and large-scale equipment is not used; the prepared cerium dioxide has high photocatalytic degradation efficiency, and compared with commercial cerium dioxide, the degradation capability of the prepared cerium dioxide to tetracycline is improved by 3-5 times.

Drawings

FIG. 1 is an XRD spectrum of a sample prepared according to the present invention;

FIG. 2 is a scanning electron micrograph of a cerium oxide sample prepared according to the present invention;

FIG. 3 is a graph showing the comparison of the performance of photocatalytic tetracycline degradation.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

Referring to fig. 1-3, the present invention provides the following technical solutions:

a new type of cerium dioxide is prepared by subjecting cerium dioxide to ultrasonic treatment for a certain period of time during the preparation process to obtain ultrasonic-treated cerium dioxide.

A preparation method of novel cerium dioxide comprises the following steps:

s1, dissolving cerium nitrate in water, adding magnesium powder, performing ultrasonic treatment for a period of time, and reacting to obtain cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 drying to obtain light yellow cerium dioxide powder.

FIG. 1 is an XRD spectrum of a sample treated at high temperature, and the spectrum in FIG. 1 is consistent with a standard spectrum of cerium dioxide by comparison with the standard spectrum, which indicates that the obtained sample is cerium dioxide.

Example 1:

a preparation method of novel cerium dioxide comprises the following steps:

s1, dissolving 4mmol of cerium nitrate in 60mL of water, adding 4mmol of magnesium powder, treating for 6h by using 100W of ultrasonic waves, and reacting to obtain a cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 oven drying, and treating at 60 deg.C for 6h to obtain light yellow cerium dioxide powder.

Comparative example 1:

a preparation method of novel cerium dioxide comprises the following steps:

s1, dissolving 4mmol of cerium nitrate in 60mL of water, adding 4mmol of magnesium powder, and reacting to obtain a cerium dioxide precipitate;

s2, centrifugally separating out the precipitate of the cerium dioxide;

s3 oven drying, and treating at 60 deg.C for 6h to obtain light yellow cerium dioxide powder.

Comparative example 2:

commercial ceria is commercially available.

Fig. 2 is a scanning electron micrograph of the cerium oxide sample prepared in example 1, and it can be seen from the analysis of fig. 2 that the obtained cerium oxide is a nanoparticle.

Experimental example 1

The cerium oxides obtained in example 1 and comparative examples 1 to 2 were observed for their tetracycline photocatalytic degradation properties.

1 Experimental devices and materials

The experimental materials used in this experiment include tetracycline hydrochloride, company, all solutions in the experiment and the aqueous phase in the analysis process were prepared with deionized water.

2 photocatalytic performance evaluation method

Firstly carrying out dark reaction for 30min, taking a primary solution for centrifugal separation after the dark reaction is finished, and measuring the absorbance of supernatant liquor at the wavelength of 360nm by using an ultraviolet spectrophotometer and recording the absorbance as A₀. Centrifuging the solution every 30min under the irradiation of 300W xenon lamp, measuring absorbance of supernatant at 360nm wavelength with ultraviolet spectrophotometer, and recording as Ai,

3 Experimental methods

The illumination experiment is carried out in a cylindrical reactor, the reactor is divided into an inner part and an outer part, the outer part is a reaction container, the volume is 200mL, the reaction container is a main area of the reactor, and a small air pump is used for aeration and oxygen supply; the inside is a quartz double-layer cooling sleeve, an ultraviolet lamp is arranged on the inner layer, the interlayer is a cold water bath, and a light source is a 300W xenon lamp. The cylindrical photoreactor was placed on a magnetic stirrer to ensure uniform dispersion of ceria, and was shielded from light with a stainless steel black box. The initial concentration of the buffer solution was 10 mg.L^-1The tetracycline solution of (1). Performing photocatalytic degradation experiment, sampling at regular time, 10000 r.min^-1The cerium oxides prepared in example 1 and comparative examples 1 to 2 were respectively tested by centrifugation at the rotation speed of (1) for 10min and then filtered through a 0.45 μm filter and measured, and the results of the tests are shown in FIG. 3.

4 results of the experiment

As can be seen from the analysis of FIG. 3, the rate of degradation of tetracycline by the cerium oxide obtained in example 1 was faster than that of comparative examples 1-2, and this tendency did not change as the reaction proceeded, and the efficiency of degradation of tetracycline by the cerium oxide obtained in example 1 was about four times that of the commercial cerium oxide obtained in comparative example 2 at the 150min node. It can thus be confirmed that the cerium oxide prepared according to the present invention has higher efficiency for degradation of tetracycline than the prior art.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.