阅读说明：本技术 一种制备磁性碘七氧化五铋复合光催化材料的方法 (Method for preparing magnetic iodine hepta-bismuth oxide composite photocatalytic material ) 是由 徐龙君 王海龙 刘成伦 于 2020-06-29 设计创作，主要内容包括：一种制备磁性碘七氧化五铋复合光催化材料的方法,其属于无机催化材料领域。本发明先用水热法制备了硬磁性材料锶铁氧体SrFe<Sub>12</Sub>O<Sub>19</Sub>,再通过水热-焙烧法制备出了磁性碘七氧化五铋复合光催化材料(Bi<Sub>5</Sub>O<Sub>7</Sub>I/SrFe<Sub>12</Sub>O<Sub>19</Sub>)。本发明方法制备工艺简单、使用设备少、能耗低。制备的Bi<Sub>5</Sub>O<Sub>7</Sub>I/SrFe<Sub>12</Sub>O<Sub>19</Sub>磁性能稳定、光催化活性高,在模拟太阳光氙灯照射下,用0.1g制备的复合磁性光催化剂降解100mL浓度为10mg/L的罗丹明B溶液,120min对罗丹明B的降解率达到96.6％,在外加磁场下对光催化剂的磁回收率为89.3％,重复使用3次后对罗丹明B的降解率为91.6％。本发明制备出的产品可广泛用于光催化降解有机污染物领域。(A method for preparing a magnetic iodine-hepta-bismuth oxide composite photocatalytic material belongs to the field of inorganic catalytic materials. The invention firstly prepares the hard magnetic material strontium ferrite SrFe by a hydrothermal method 12 O 19 Then hydrothermal-roastingThe magnetic iodine hepta-bismuth oxide composite photocatalytic material (Bi) is prepared by the method 5 O 7 I/SrFe 12 O 19 ). The method has the advantages of simple preparation process, less used equipment and low energy consumption. Prepared Bi 5 O 7 I/SrFe 12 O 19 The magnetic property is stable, the photocatalytic activity is high, under the irradiation of a simulated sunlight xenon lamp, 100mL of 10mg/L rhodamine B solution is degraded by using 0.1g of prepared composite magnetic photocatalyst, the degradation rate of rhodamine B in 120min reaches 96.6%, the magnetic recovery rate of the photocatalyst under an external magnetic field is 89.3%, and the degradation rate of rhodamine B after repeated use for 3 times is 91.6%. The product prepared by the invention can be widely used in the field of photocatalytic degradation of organic pollutants.)

1. A method for preparing a magnetic iodine-hepta-bismuth oxide composite photocatalytic material is characterized by comprising the following steps:

(1) preparation of strontium ferrite

Preparation of SrFe by hydrothermal method₁₂O₁₉2.1624g of FeCl were weighed out separately₃·6H₂O and 0.2666g SrCl₂·6H₂O, adding 20mL of distilled water into a beaker, and then carrying out ultrasonic oscillation until the solid is completely dissolved; dropwise adding a NaOH solution with the concentration of 5.2mol/L into the mixed solution under the action of magnetic stirring, and continuously stirring for 10min after adjusting the pH of the solution to 10; then transferring the mixed solution into a 100mL polytetrafluoroethylene inner container, sealing the mixed solution in a stainless steel reaction kettle, and placing the stainless steel reaction kettle in a drying oven with the temperature of 200 ℃ for reaction for 24 hours; after the reaction is finished, soaking the filter cake obtained by suction filtration for 1h by using dilute hydrochloric acid, repeatedly washing the filter cake by using distilled water, drying the filter cake for 24h at 65 ℃, and finally grinding the filter cake to obtain SrFe₁₂O₁₉；

(2) Preparation of magnetic iodine hepta-bismuth oxide composite photocatalytic material

Respectively measuring 5mL of ethylene glycol and 35mL of distilled water, and mixing to obtain a mixed solution; 0.97g of Bi (NO) is weighed₃)₃·5H₂Adding O into the mixed solution, and performing ultrasonic treatment for 10min to obtain a suspension; weighing 0.332g of KI, adding the KI into the suspension, and stirring for 35 min; weighing 5-15 wt% of SrFe prepared in the step (1)₁₂O₁₉Adding into the above suspension, mechanically stirring the suspension for 30min, transferring into 100mL polytetrafluoroethylene liner, sealing in stainless steel reaction kettle, and baking at 160 deg.CReacting for 12h in the box; after the reaction is finished, filtering to obtain a filter cake as an intermediate product, washing the intermediate product for a plurality of times by using distilled water and absolute ethyl alcohol, and drying the intermediate product for 5 hours at the temperature of 80 ℃; then placing the intermediate product into a 100mL ceramic crucible, and placing the ceramic crucible into a muffle furnace at 480 ℃ for continuous roasting for 2 hours; cooling to room temperature, and grinding to obtain the magnetic iodine-hepta-bismuth oxide composite photocatalytic material.

2. The preparation method of the magnetic iodine hepta-bismuth oxide composite photocatalytic material as claimed in claim 1, wherein the preparation method is a hydrothermal-roasting method, so that effective compounding of a magnetic matrix strontium ferrite and an active component iodine hepta-bismuth oxide is realized.

Technical Field

The invention relates to a method for preparing magnetic iodine pentabismuth (Bi) oxide₅O₇I/SrFe₁₂O₁₉) A method for preparing a composite photocatalytic material belongs to the technical field of inorganic environment photocatalytic materials.

Background

Iodine hepta-bismuth oxide (Bi)₅O₇I) Belongs to oxygen-enriched bismuth oxyhalide and is a novel nano photocatalytic material. Bi₅O₇The I conduction band bottom consists of the Bi 6p orbital, and the valence band top consists of the Bi 6s, O2 p, and I5 p orbitals. Bi 6s and O2 p orbitals can form a large number of dispersed hybrid valence bands, which is beneficial to the migration and oxidation reaction of photo-generated holes, and the introduction of the I5 s orbitals further disperses the valence bands and increases the mobility of the photo-generated holes. At the same time, Bi₅O₇The permanent electrostatic field between the first layer and the second layer can be used as an accelerator for separating photoproduction electrons from photoproduction holes, and is favorable for improving Bi₅O₇Photocatalytic activity of I. Bi₅O₇The common preparation method of the I comprises a hydrothermal method, a roasting method, a coprecipitation method and the like, the photocatalytic material can be dispersed in liquid when pollutants are degraded in a photocatalytic manner, and the practical application of the photocatalytic material is restricted by the difficulty in separation and recovery. The composite magnetic photocatalytic material realizes the recycling of the catalytic material through an external magnetic field, and overcomes the defects of high energy consumption, long time consumption and complex process of the conventional recycling modes such as centrifugation or filtration and the like.

Strontium ferrite (SrFe)₁₂O₁₉) The magnetic material belongs to hard magnetic ferrite and has the advantages of high coercive force, large residual magnetic flux density, low production cost, strong product stability and the like. At present, the common SrFe₁₂O₁₉The preparation method comprises a ball milling method, a thermal decomposition method, a sol-gel method, an ultrasonic precipitation method and the like.

At present, to Bi₅O₇The research of I focuses mainly on improving the photocatalytic activity thereof, and neglects the recovery and reuse of catalytic materials. Such as "Journal of Materials Science: materials in Electronics "Enhance in volume 29 of 2018d photocatalytic performance of Z-scheme Cu₂O/Bi₅O₇Inanocomposides (reference 1), pure Bi was prepared by a baking method₅O₇I, then recombination is carried out to obtain Cu₂O/Bi₅O₇I composite photocatalytic material. The method has the disadvantages that: (1) preparation of Bi₅O₇When I is carried out, a glycol solution of potassium iodide (KI) is slowly dripped into bismuth nitrate pentahydrate (Bi (NO)₃)₃·5H₂O) in a glycol solution and reacting in a high-pressure kettle for 24h (120 ℃) to form a precursor, then washing and roasting to obtain the product, wherein the precursor is generated by reacting in a glycol system of a pure organic solvent, so that the cost is high, the energy consumption is high, and high-concentration organic wastewater can be generated; (2) prepared Bi₅O₇The catalytic activity of I is not high, the degradation rate of 120min to rhodamine B is only 52 percent, and the compound Cu of I and cuprous oxide₂O/Bi₅O₇The degradation rate of I is 95.5%; (3) the recovery cost of the photocatalytic material (centrifugation or suction filtration) is high, and secondary pollution is easily caused due to incomplete recovery.

For another example, in the invention patent "a preparation method of a strontium ferrite loaded bismuth vanadate composite photocatalyst" (publication No. CN103480384A) (reference 2), a roasting method is used to prepare strontium ferrite, and then a dipping roasting method is used to prepare the strontium ferrite/bismuth vanadate composite magnetic photocatalyst. The method has the following disadvantages: (1) the strontium ferrite is prepared by roasting at 800-1000 ℃ for 2-4 h, and the energy consumption is high; (2) the composite magnetic photocatalyst prepared by the method has poor photocatalytic stability, and the degradation rate of the recycled photocatalyst to methylene blue is reduced from 93% to 60% within 5 h.

Disclosure of Invention

The purpose of the invention is to provide Bi₅O₇I the problem that the catalytic activity is not high and the recovery and the reuse are difficult, provides a magnetic Bi₅O₇I/SrFe₁₂O₁₉The preparation method of the composite photocatalytic material is simple and low in cost. Prepared magnetic Bi₅O₇I/SrFe₁₂O₁₉The composite photocatalytic material has higher photocatalytic activity under the irradiation of simulated sunlight,and the catalyst is convenient to separate and recover from a liquid phase system through an external magnetic field, and the recovered catalytic material still has high photocatalytic activity. The method not only realizes resource recycling simply and efficiently, but also avoids secondary pollution possibly caused by incomplete recycling of catalytic materials.

Bi of the invention₅O₇I/SrFe₁₂O₁₉The preparation method comprises the following steps:

(1)SrFe₁₂O₁₉preparation of

Preparation of SrFe by hydrothermal method₁₂O₁₉2.1624g of FeCl were weighed out separately₃·6H₂O and 0.2666g SrCl₂·6H₂O, adding 20mL of distilled water into a beaker, and then carrying out ultrasonic oscillation until the solid is completely dissolved; dropwise adding a NaOH solution with the concentration of 5.2mol/L into the mixed solution under the action of magnetic stirring, and continuously stirring for 10min after adjusting the pH of the solution to 10; then transferring the mixed solution into a 100mL polytetrafluoroethylene inner container, sealing the mixed solution in a stainless steel reaction kettle, and placing the stainless steel reaction kettle in a drying oven with the temperature of 200 ℃ for reaction for 24 hours; after the reaction is finished, soaking the filter cake obtained by suction filtration for 1h by using dilute hydrochloric acid, repeatedly washing the filter cake by using distilled water, drying the filter cake for 24h at 65 ℃, and finally grinding the filter cake to obtain SrFe₁₂O₁₉。

(2)Bi₅O₇I/SrFe₁₂O₁₉Preparation of composite magnetic photocatalytic material

Bi is prepared by adopting a hydrothermal-roasting method₅O₇I/SrFe₁₂O₁₉Respectively weighing 5mL of ethylene glycol and 35mL of distilled water, and mixing to obtain a mixed solution; 0.97g of Bi (NO) is weighed₃)₃·5H₂Adding O into the mixed solution, and performing ultrasonic treatment for 10min to obtain a suspension; weighing 0.332g of KI, adding the KI into the suspension, and stirring for 35 min; then weighing 5-15% of SrFe prepared in the step (1)₁₂O₁₉Adding the suspension into the suspension, mechanically stirring the suspension for 30min, transferring the suspension into a 100mL polytetrafluoroethylene inner container, sealing the inner container in a stainless steel reaction kettle, and placing the stainless steel reaction kettle in a drying oven at the temperature of 160 ℃ for reaction for 12 h; after the reaction is finished, filter cakes obtained by suction filtration are taken as the middleWashing the product with distilled water and absolute ethyl alcohol for several times, and drying at 80 ℃ for 5 h; then placing the intermediate product into a 100mL ceramic crucible, and placing the ceramic crucible into a muffle furnace at 480 ℃ for continuous roasting for 2 hours; cooling to room temperature and grinding to obtain Bi₅O₇I/SrFe₁₂O₁₉A composite photocatalytic material.

By adopting the technical scheme, the invention mainly has the following effects:

(1) magnetic Bi prepared by the method of the invention₅O₇I/SrFe₁₂O₁₉The composite photocatalytic material has high photocatalytic activity, and 0.1g of magnetic Bi prepared under the irradiation of a simulated sunlight xenon lamp₅O₇I/SrFe₁₂O₁₉The composite photocatalytic material is dispersed in 100mL of 10mg/L rhodamine B solution, and the degradation rate of the rhodamine B after 120min of illumination reaches 96.6 percent (which is better than that of Cu prepared by the comparison document 1)₂O/Bi₅O₇I composite photocatalytic material).

(2) Magnetic Bi prepared by the method of the invention₅O₇I/SrFe₁₂O₁₉The recovery rate of the composite photocatalytic material under the action of an external magnetic field is up to 89.3%, and the degradation rate of the composite photocatalytic material after 3 times of repeated use is still up to 91.6%.

(3) Magnetic Bi prepared by the method of the invention₅O₇I/SrFe₁₂O₁₉The composite photocatalytic material has the advantages of simple preparation and operation method, less required equipment and low energy consumption.

Drawings

FIG. 1 shows Bi₅O₇I、SrFe₁₂O₁₉And Bi₅O₇I/SrFe₁₂O₁₉X-ray diffraction pattern of (a).

FIG. 2 shows Bi₅O₇I/SrFe₁₂O₁₉Scanning electron microscopy of (a).

FIG. 3 shows SrFe₁₂O₁₉And Bi₅O₇I/SrFe₁₂O₁₉Magnetic hysteresis loop diagram of (1).

Detailed Description

The present invention will be further described with reference to the following specific embodiments.