Double Z type CuO/CuBi2O4/Bi2O3Composite photocatalyst and preparation method and application thereof
阅读说明：本技术 双Z型CuO/CuBi2O4/Bi2O3复合光催化剂及其制备方法和应用 (Double Z type CuO/CuBi2O4/Bi2O3Composite photocatalyst and preparation method and application thereof ) 是由 张朝红 么鸿砜 王君 铁梅 房大维 于 2021-09-26 设计创作，主要内容包括：本发明涉及双Z型CuO/CuBi-(2)O-(4)/Bi-(2)O-(3)复合光催化剂及其制备方法和应用。将Cu(OH)-(2)和Bi(OH)-(3)分散于蒸馏水中,充分搅拌使混合溶液均匀后进行过滤,将过滤得到的沉淀混合物在50℃干燥12h,干燥后的粉末均匀研磨,放入马弗炉中于350～550℃,煅烧2～5h,得目标产物CuO/CuBi-(2)O-(4)/Bi-(2)O-(3)。本发明通过控制煅烧温度与煅烧时间,能够使三种纳米粒子共存,基于不完全固相反应制备的双Z型CuO/CuBi-(2)O-(4)/Bi-(2)O-(3)复合光催化剂,在太阳光下可高效光催化降解水中有机污染物。(The invention relates to double Z type CuO/CuBi 2 O 4 /Bi 2 O 3 A composite photocatalyst and a preparation method and application thereof. Mixing Cu (OH) 2 And Bi (OH) 3 Dispersing in distilled water, fully stirring to make the mixed solution uniform, filtering, drying the precipitate mixture obtained by filtering at 50 ℃ for 12h, uniformly grinding the dried powder, putting the powder into a muffle furnace, calcining at 350-550 ℃ for 2-5 h to obtain the target product CuO/CuBi 2 O 4 /Bi 2 O 3 . According to the invention, by controlling the calcination temperature and the calcination time, three types of nano particles can coexist, and the double Z-type CuO/CuBi prepared based on incomplete solid-phase reaction can be prepared 2 O 4 /Bi 2 O 3 A composite photocatalyst which can be used under sunlightHigh-efficiency photocatalytic degradation of organic pollutants in water.)
1. Double Z type CuO/CuBi2O4/Bi2O3The composite photocatalyst is characterized in that the preparation method comprises the following steps: mixing Cu (OH)2And Bi (OH)3Dispersing in distilled water, stirring for 3-4 h, filtering, and drying the filtered precipitate at 50 ℃ for 12 h; uniformly grinding the dried powder, putting the powder into a muffle furnace, calcining at 350-550 ℃ for 2-5 h to obtain a target product CuO/CuBi2O4/Bi2O3。
2. The double Z-type CuO/CuBi of claim 12O4/Bi2O3A composite photocatalyst is characterized in that, in terms of molar ratio, Cu (OH)2:Bi(OH)3＝1:1。
3. The double Z-type CuO/CuBi of claim 1 or 22O4/Bi2O3A composite photocatalyst, characterized in that said Cu (OH)2The preparation method comprises the following steps: adding Cu (NO)3)2·3H2Dissolving O in deionized water, stirring to dissolve the O, dropwise adding a NaOH solution, magnetically stirring, standing, removing a supernatant, washing a precipitate with distilled water until the pH of an eluate is 7-8, and centrifuging to obtain Cu (OH)2。
4. The double Z-type CuO/CuBi of claim 1 or 22O4/Bi2O3A composite photocatalyst, characterized in that said Bi (OH)3The preparation method comprises the following steps: adding Bi (NO)3)3·5H2Dissolving O in ethylene glycol, stirring to dissolve, then dropwise adding a NaOH solution, magnetically stirring, standing, removing a supernatant, washing a precipitate with distilled water until the pH of an eluate is 7-8, and centrifuging to obtain Bi (OH)3。
5. The double Z-type CuO/CuBi of claim 1 or 22O4/Bi2O3The application of the composite photocatalyst in degrading antibiotics under sunlight.
6. Use according to claim 5, characterized in that the method is as follows: adding double Z type CuO/CuBi into solution containing antibiotics2O4/Bi2O3And (3) irradiating the composite photocatalyst for 3-4 hours under sunlight.
7. Use according to claim 6, characterized in that the double Z-form CuO/CuBi2O4/Bi2O3The adding amount of the composite photocatalyst is 0.5-2.0 g/L.
8. Use according to any one of claims 5 to 7, wherein the antibiotic is a quinolone antibiotic.
9. The use according to claim 8, characterized in that said quinolone antibiotic is norfloxacin.
Technical Field
The invention belongs to the field of photocatalysts, and particularly relates to a method for preparing double Z-shaped CuO/CuBi by adopting a chemical precipitation method and an incomplete solid-phase reaction method2O4/Bi2O3A composite photocatalyst and application thereof in catalyzing and degrading antibiotic wastewater under sunlight.
Background
Antibiotics are typical persistent organic pollutants, and Norfloxacin (NFX) is used as a third-generation quinolone antibiotic, is an antibiotic drug with broad spectrum, and is widely applied to treatment of diseases of human beings and animals. Since these antibiotics are used in large quantities and cannot be completely absorbed in the human body and livestock, residues are released into water, causing a series of environmental pollution problems. Therefore, a large amount of NFX residual substances are often present in the natural environment. At present, environmental protection and management have attracted extensive attention from countries in the world. The traditional treatment methods such as a microbiological method, a physical method and a chemical method have the problems of unsatisfactory treatment effect, high treatment cost, secondary pollution to the environment and the like. In recent years, the photocatalytic oxidation technology has become a better choice for treating antibiotics in wastewater due to the characteristics of strong redox capability, no secondary pollution, low cost, good degradation effect after repeated utilization and the like.
In the research of photocatalytic oxidation technology, a ternary double-Z type photocatalytic structural system formed by compounding a wide band gap semiconductor with a proper band gap structure and a narrow band gap semiconductor is one of effective ways for improving photocatalytic activity. CuBi2O4As a typical p-type semiconductor material, the material has a forbidden band width of about 1.7eV, and attracts attention due to a narrow band gap and good photocatalytic performance. CuO belongs to a monoclinic system and is a few metal oxide semiconductors. When the nano-grade nano. The bismuth-based compound mainly contains metal bismuth and other bismuth compounds, has special layered structure and appropriate forbidden band width, and is Bi2O3Is the simplest bismuth-based compound, and is considered to be a promising visible light photocatalyst due to a special electronic structure and excellent visible light response performance. The three semiconductors have proper band gap structures and good catalysisThe performance and chemical property stability, low cost, simple preparation process and the like, and has stronger degradation capability on antibiotic wastewater and dye wastewater, thereby having important research value.
Disclosure of Invention
The object of the present invention is achieved by Cu (OH)2And Bi (OH)3By controlling the calcination temperature and time, a portion of the reaction mixture is converted into CuBi2O4The other part generates CuO and Bi under the high temperature condition2O3Further, the three components coexist in a form of almost no interface to form the double Z-type CuO/CuBi2O4/Bi2O3A composite photocatalyst is provided. The construction of the composite system improves the oxidation reduction capability of the system, reduces the recombination rate of electrons and holes, and can fully utilize sunlight to enhance the photocatalytic activity.
Another object of the present invention is to utilize the double Z-type CuO/CuBi2O4/Bi2O3The composite photocatalyst catalyzes and degrades antibiotics in water.
The technical scheme adopted by the invention is as follows: double Z type CuO/CuBi2O4/Bi2O3The preparation method of the composite photocatalyst comprises the following steps: mixing Cu (OH)2And Bi (OH)3Dispersing in distilled water, stirring for 3-4 h, filtering, and drying the filtered precipitate at 50 ℃ for 12 h; uniformly grinding the dried powder, putting the powder into a muffle furnace, calcining at 350-550 ℃ for 2-5 h to obtain a target product CuO/CuBi2O4/Bi2O3。
Further, the double Z-type CuO/CuBi2O4/Bi2O3Composite photocatalyst, in molar ratio, Cu (OH)2:Bi(OH)3＝1:1。
Further, the double Z-type CuO/CuBi2O4/Bi2O3Composite photocatalyst, said Cu (OH)2The preparation method comprises the following steps: adding Cu (NO)3)2·3H2Dissolving O in deionized water, stirring to dissolve, and dropwise adding NaOH solutionMagnetically stirring, standing, removing supernatant, washing precipitate with distilled water until the pH of eluate is 7-8, and centrifuging to obtain Cu (OH)2。
Further, the double Z-type CuO/CuBi2O4/Bi2O3Composite photocatalyst of Bi (OH)3The preparation method comprises the following steps: adding Bi (NO)3)3·5H2Dissolving O in ethylene glycol, stirring to dissolve, then dropwise adding a NaOH solution, magnetically stirring, standing, removing a supernatant, washing a precipitate with distilled water until the pH of an eluate is 7-8, and centrifuging to obtain Bi (OH)3。
The invention provides double Z-type CuO/CuBi2O4/Bi2O3The application of the composite photocatalyst in degrading antibiotics under sunlight.
Further, the method is as follows: adding double Z type CuO/CuBi into solution containing antibiotics2O4/Bi2O3And (3) irradiating the composite photocatalyst for 3-4 hours under sunlight.
Further, double Z-type CuO/CuBi2O4/Bi2O3The adding amount of the composite photocatalyst is 0.5-2.0 g/L.
Further, the antibiotic is a quinolone antibiotic.
Still further, the quinolone antibiotic is Norfloxacin (NFX).
The invention has the beneficial effects that: the invention prepares double Z type CuO/CuBi through incomplete solid phase reaction2O4/Bi2O3The composite photocatalyst has simple preparation method and can ensure that CuO and CuBi are mixed2O4、Bi2O3The photo-generated electrons coexist in a form of almost no interface, and the transmission efficiency of the photo-generated electrons is improved. Double Z type CuO/CuBi2O4/Bi2O3The construction of the composite photocatalyst not only can effectively utilize sunlight, but also improves the oxidation-reduction capability of the system and the photoproduction of electron-hole pairs (e)--h+) The photocatalytic activity is further improved.
Drawings
Fig. 1 is an X-ray diffraction pattern of CuO.
FIG. 2 is Bi2O3X-ray diffraction pattern of (a).
FIG. 3 is CuBi2O4X-ray diffraction pattern of (a).
FIG. 4 is a CuO/CuBi diagram2O4/Bi2O3X-ray diffraction pattern of (a).
FIG. 5 is a CuO/CuBi diagram2O4/Bi2O3Scanning electron microscopy of (a).
FIG. 6 is CuO/CuBi2O4/Bi2O3Transmission electron microscopy images of (a).
FIG. 7 is a CuO/CuBi diagram2O4/Bi2O3Ultraviolet and visible diffuse reflection absorption spectrogram.
FIG. 8 is a graph of UV-VIS absorption of norfloxacin solutions degraded by different catalysts.
Detailed Description
Example 1
(one) double Z type CuO/CuBi2O4/Bi2O3The preparation method of the composite photocatalyst comprises the following steps:
1) preparation of Cu (OH) by chemical precipitation2: first, 1.210g of Cu (NO) was weighed3)2·3H2O in a beaker, 50mL of deionized water was added thereto, and the mixture was magnetically stirred for 30min to be completely dissolved. Secondly, 10mL of 1.0mol/L NaOH solution is dropwise added into a beaker, magnetically stirred for 1.0h and then kept stand until Cu (OH)2The supernatant was removed after precipitation was complete. Washing the precipitate with deionized water until the pH of an eluate is 7-8, and centrifuging to obtain Cu (OH)2。
2) Preparation of Bi (OH) by chemical precipitation3: first, 2.425g of Bi (NO) was weighed3)3·5H2O in a beaker, 100mL of ethylene glycol was added thereto and stirring was continued for 30min to completely dissolve it. Secondly, 15mL of 1.0mol/L NaOH solution is dropwise added into a beaker, magnetically stirred for 1.0h and then kept stand until Bi (OH)3The supernatant was removed after precipitation was complete. And washing the precipitate with deionized waterWashing until the pH of the eluate is 7-8, and centrifuging to obtain Bi (OH)3。
3) Preparation of CuO/CuBi by incomplete solid phase reaction2O4/Bi2O3The composite photocatalyst comprises: mixing the above prepared Cu (OH)2And Bi (OH)3Mixing at a molar ratio of 1:1, dispersing in distilled water, stirring for 3.0 hr, filtering, and drying the filtered mixed precipitate at 50 deg.C for 12 hr. After drying, the powder is put into a mortar for even grinding and then put into a crucible. Calcining at 350 deg.C, 450 deg.C and 550 deg.C for 3.0h, and calcining at 450 deg.C for 2.0h, 4.0h and 5.0h, respectively. The obtained products are respectively marked as CuO/CuBi2O4/Bi2O3(350-3)、CuO/CuBi2O4/Bi2O3(450-3)、CuO/CuBi2O4/Bi2O3(550-3)、CuO/CuBi2O4/Bi2O3(450-2)、CuO/CuBi2O4/Bi2O3(450-4)、CuO/CuBi2O4/Bi2O3(450-5)。
(II) comparative example
Preparing CuO nano particles: first, 1.210g of Cu (NO) was weighed3)2·3H2O in a beaker, 50mL of deionized water was added thereto, and the mixture was magnetically stirred for 30min to be completely dissolved. Secondly, 10mL of 1.0mol/L NaOH solution is dropwise added into a beaker, magnetically stirred for 1.0h and then kept stand until Cu (OH)2The supernatant was removed after precipitation was complete. Washing the precipitate with deionized water until the pH of an eluate is 7-8, and centrifuging to obtain Cu (OH)2And (4) precipitating. And drying the obtained precipitate at 50 ℃ for 12h, uniformly grinding the dried precipitate, and putting the dried precipitate into a crucible to calcine the precipitate at 450 ℃ for 4.0h in a muffle furnace to obtain the CuO nano particles.
Preparation of Bi2O3Nanoparticle: first, 2.425g of Bi (NO) was weighed3)3·5H2O in a beaker, 100mL of ethylene glycol was added thereto and stirring was continued for 30min to completely dissolve it. Secondly, 15mL of 1.0mol/L NaOH solution is dropwise added into a beaker, magnetically stirred for 1.0h and then kept stand until Bi (OH)3The supernatant was removed after precipitation was complete. And areWashing the precipitate with deionized water until the pH of an eluate is 7-8, and centrifuging to obtain Bi (OH)3And (4) precipitating. Drying the obtained precipitate at 50 ℃ for 12h, uniformly grinding the dried precipitate, and calcining the dried precipitate in a crucible at 450 ℃ for 4.0h to obtain Bi2O3Nanoparticles.
Preparation of CuBi2O4Nanoparticle: first, 0.6050g of Cu (NO) was weighed3)2·3H2O was dissolved in 30mL of deionized water and stirred to dissolve it. Dropwise adding 5mL of 1.0mol/L NaOH solution into the solution, magnetically stirring for 1.0h, standing until Cu (OH)2The supernatant was removed after precipitation was complete. Washing the precipitate with deionized water until the pH of an eluate is 7-8, and centrifuging to obtain Cu (OH)2And (4) precipitating. Next, 2.425g of Bi (NO) was weighed3)3·5H2Dissolving O in 100mL of ethylene glycol, stirring continuously to dissolve completely, dropwise adding 15mL of 1.0mol/L NaOH solution, magnetically stirring for 1.0h, standing until Bi (OH)3The supernatant was removed after precipitation was complete. Washing the precipitate with deionized water until the pH of an eluate is 7-8, and centrifuging to obtain Bi (OH)3And (4) precipitating. Finally, the obtained Cu (OH)2And Bi (OH)3Dispersing the precipitate in distilled water, stirring for 3.0h, filtering, drying the filtered precipitate mixture at 50 deg.C for 12h, grinding the dried powder, calcining in a muffle furnace at 700 deg.C for 3.0h to obtain CuBi2O4Nanoparticles.
(III) characterization of the catalyst
Fig. 1 is an XRD spectrum of the CuO nanoparticles prepared in the comparative example, and as shown in fig. 1, the characteristic peaks of CuO are consistent with those of the standard card (JCPDS 80-1917). The results show that CuO was successfully prepared.
FIG. 2 shows Bi prepared in comparative example2O3XRD pattern of the nanoparticles, as shown in FIG. 2, Bi2O3Can be clearly seen and corresponds one-to-one with the standard card (JCPDS 71-2274), which indicates that Bi2O3The preparation is successful.
FIG. 3 is CuBi prepared in comparative example2O4The XRD pattern of the nanoparticles, as shown in figure 3,CuBi2O4the characteristic peaks of (A) are in accordance with the standard card (JCPDS 71-1774). The results show that CuBi is successfully synthesized2O4。
FIG. 4 is a double Z-type CuO/CuBi2O4/Bi2O3(450-4) XRD pattern of the composite photocatalyst, as shown in figure 4, belongs to CuO and CuBi2O4、Bi2O3Characteristic peaks of the three substances can be observed, and the result shows that CuO/CuBi is successfully prepared2O4/Bi2O3(450-4) the composite photocatalyst.
FIG. 5 is a CuO/CuBi diagram2O4/Bi2O3(450-4) scanning electron microscopy images. As can be seen from FIG. 5, the cubic rhombus-shaped CuO and the short rod-shaped Bi having a smooth surface2O3And relatively massive CuBi2O4All can be observed, and the test result shows that the CuO/CuBi is successfully prepared2O4/Bi2O3A composite photocatalyst is provided.
FIG. 6 is CuO/CuBi2O4/Bi2O3(450-4) transmission electron microscopy image. From FIG. 6, it can be clearly seen that the lattice fringes and widths in three different directions are CuO and Bi respectively through comparison2O3And CuBi2O4Nanoparticles, thus the results demonstrate the coexistence of three nanoparticles, CuO/CuBi2O4/Bi2O3The composite photocatalyst is successfully prepared.
FIG. 7 is a CuO/CuBi diagram2O4/Bi2O3(450-4) ultraviolet visible diffuse reflectance absorption spectrum. As shown in FIG. 7, the prepared CuO/CuBi2O4/Bi2O3The composite photocatalyst has an absorption wavelength of 200-800nm, and can effectively utilize sunlight.
Example 2 double Z-type CuO/CuBi2O4/Bi2O3Application of composite photocatalyst in degradation of antibiotics under sunlight
Influence of (I) catalyst calcination temperature on norfloxacin degradation rate
The experimental method comprises the following steps: 0.03g of CuO/CuBi was weighed out separately2O4/Bi2O3(350-3)、CuO/CuBi2O4/Bi2O3(450-3) and CuO/CuBi2O4/Bi2O3(550-3) irradiating the mixture in 3 quartz tubes containing 30mL of NFX solution with the initial concentration of 5mg/L under sunlight for 3h, centrifuging to obtain a supernatant, filtering the supernatant, and measuring the absorbance within the wavelength range of 200-800 nm. The absorbance at 274.9nm was substituted into the standard curve formula and the NFX degradation rate was calculated. The results are shown in Table 1.
Percent degradation rate (%) (1-C/C)0) X 100% (wherein C)0: NFX concentration in the stock solution; c: concentration of NFX in the sample).
TABLE 1 influence of catalyst calcination temperature on norfloxacin degradation rate
As can be seen from Table 1, the composite photocatalyst CuO/CuBi prepared at the calcination temperature of 450 ℃ is2O4/Bi2O3(450-3) the degradation NFX effect is best, the degradation rate can reach 63.91% after being irradiated for 3 hours in sunlight, so the double Z type CuO/CuBi prepared by the invention2O4/Bi2O3The calcination temperature of the composite photocatalyst is 450 ℃.
Influence of (II) catalyst calcination time on norfloxacin degradation rate
The experimental method comprises the following steps: 0.03g of CuO/CuBi was weighed out separately2O4/Bi2O3(450-2)、CuO/CuBi2O4/Bi2O3(450-3)、CuO/CuBi2O4/Bi2O3(450-4) and CuO/CuBi2O4/Bi2O3(450-5) in 4 quartz tubes added with 30mL of NFX solution with the initial concentration of 5mg/L, irradiating for 3h under the sunlight, centrifuging to obtain the supernatant, filtering the supernatant, and then measuring the absorbance within the wavelength range of 200-800 nm.The absorbance at 274.9nm was substituted into the standard curve formula and the NFX degradation rate was calculated. The results are shown in Table 2.
TABLE 2 influence of catalyst calcination time on norfloxacin degradation rate
As can be seen from Table 2, when the calcination temperature is 450 ℃ and the calcination time is 4 hours, the prepared double Z-type CuO/CuBi2O4/Bi2O3(450-4) the composite photocatalyst has the highest degradation rate to NFX, and the degradation rate is 74.52%.
(III) influence of different catalysts on degradation rate of norfloxacin
0.03g of CuO and Bi were weighed out separately2O3、CuBi2O4And CuO/CuBi2O4/Bi2O3(450-4) irradiating for 3h under sunlight in 4 quartz tubes into which 30mL of NFX solution with the initial concentration of 5mg/L is added, centrifuging to obtain the supernatant, filtering the supernatant, and measuring the absorbance within the wavelength range of 200-800 nm. The absorbance at 274.9nm was substituted into the standard curve formula and the NFX degradation rate was calculated. The results are shown in table 3 and fig. 8.
TABLE 3 Effect of different catalysts on norfloxacin degradation Rate
As can be seen from Table 3, compared with 3 monomers, the double Z-type CuO/CuBi prepared by the invention2O4/Bi2O3The composite photocatalyst has the best degradation effect on NFX pollutants, and the degradation rate can reach 74.52%.
As can be seen from FIG. 8, in sunlight, CuO and Bi are present2O3、CuBi2O4Monomer and CuO/CuBi2O4/Bi2O3(450-4) the composite photocatalyst has the degradation effect on NFX, but the double Z type CuO/CuBi2O4/Bi2O3(450-4) the composite photocatalyst has the most obvious effect of degrading NFX solution.
Influence of (IV) illumination time on norfloxacin degradation rate
4 parts of 0.03g CuO/CuBi are weighed out2O4/Bi2O3(450-4) in 4 quartz tubes added with 30mL of NFX solution with the initial concentration of 5mg/L, irradiating for different times under the sunlight, sampling, centrifuging to obtain the supernatant, filtering the supernatant, and then measuring the absorbance within the wavelength range of 200-800 nm. The absorbance at 274.9nm was substituted into the standard curve formula and the NFX degradation rate was calculated. The results are shown in Table 4.
TABLE 4 Effect of light time on norfloxacin degradation Rate
As can be seen from Table 4, the NFX degradation rate increases with the increase of the illumination time, and when the illumination is carried out for 240min, the NFX degradation degree is the maximum, and the degradation rate can reach 82.34%.
(V) influence of different adding amounts of catalyst on degradation rate of norfloxacin
30mL of norfloxacin solution with initial concentration of 5mg/L is measured and respectively placed in 4 quartz tubes, and CuO/CuBi with different dosages are respectively added2O4/Bi2O3(450-4) irradiating the composite photocatalyst for 3h under the sunlight, centrifuging to obtain a supernatant, filtering the supernatant, and then measuring the absorbance of the supernatant in the wavelength range of 200-800 nm. The absorbance at 274.9nm was substituted into the standard curve formula and the NFX degradation rate was calculated. The results are shown in Table 5.
Percent degradation rate (%) (1-C/C)0) X 100% (wherein C)0: the concentration of the stock solution; c: concentration of sample).
TABLE 5 Effect of different amounts of catalyst on norfloxacin degradation
As can be seen from Table 5, the degradation rate of NFX increased and then decreased as the amount of catalyst added increased. When the adding amount of the catalyst is 1.0g/L, the CuO/CuBi is added2O4/Bi2O3(450-4) the highest degradation rate of the composite photocatalyst to NFX is 74.52%.
In the above examples, norfloxacin was used as the antibiotic, but norfloxacin is not a limitation to the antibiotic degraded by the present invention, and the method of the present invention is suitable for degrading any antibiotic and dye wastewater.
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