Zr-BiOI / GO composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of photocatalytic materials, and discloses a Zr-BiOI / GO composite material and a preparation method and application thereof. The preparation method comprises the following steps: dispersing iodized salt in a water solvent A to obtain a solution A; dispersing graphene oxide in a water solvent B to obtain a solution B; the preparation method comprises the following steps: dispersing a bismuth source and a zirconium source in an organic solvent, and stirring at 30-90 DEG C to obtain a solution C; and adding the solution B into the solution C under the stirring action, then adding the solution A, adjusting the pH value to 10, stirring, cooling to room temperature, filtering, washing, drying and grinding to obtain the Zr-BiOI / GO composite material. The Zr-BiOI / GO composite photocatalytic material prepared by the invention has the characteristics of large specific surface area, good photocatalytic performance, high utilization rate of visible light and the like, the preparation method is simple, the photocatalytic effect is good, and the production cost of the composite material is low.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and particularly relates to a Zr-BiOI / GO composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its unique layered structure and relatively narrow bandgap, bismuth oxyiodide (BiOI) has been widely studied as a photocatalyst and shown significant potential. However, since the photo-generated electron-hole pairs in BiOI are prone to recombination, its photocatalytic activity is affected, which severely limits the further application and development of BiOI as a photocatalyst. To improve the photocatalytic efficiency of BiOI, methods such as morphology regulation, noble metal deposition, and semiconductor compounding can be used. Although these methods can improve the photocatalytic activity to a certain extent, there are still problems such as easy recombination of electron-hole pairs and relatively narrow visible light response range.

[0003] Therefore, the present invention provides a Zr-BiOI / GO composite material, a preparation method thereof, and an application thereof. Summary of the Invention

[0004] To solve the above deficiencies in the prior art, the present invention provides a Zr-BiOI / GO composite material, a preparation method thereof, and an application thereof. The present invention uses a hydrolysis method to obtain a Zr-BiOI / GO composite photocatalytic material. GO, as a carrier, provides a large number of binding sites and promotes the rapid transport of carriers; BiOI, as a semiconductor with a relatively narrow bandgap, has good visible light response performance. After hydrothermal compounding, no new phase appears in the Zr-doped sample, and the sample retains the crystal phase structure of the original BiOI. It is possible that Zr enters the BiOI lattice to form a substitutional solid solution. And in the Zr-BiOI / GO composite photocatalytic material system prepared by the present invention, electrons (e - ) rapidly move from BiOI to Zr, inducing a reduction reaction; holes (h + ) can migrate to the surface of BiOI, inducing an oxidation reaction; electrons and holes can be effectively separated, while inhibiting their recombination, overcoming the deficiency that the photo-generated electron-hole pairs of single BiOI are prone to recombination, and improving the photocatalytic activity.

[0005] The Zr-BiOI / GO composite material, a preparation method thereof, and an application thereof of the present invention are realized through the following technical solutions:

[0006] The first object of the present invention is to provide a preparation method of a Zr-BiOI / GO composite material, comprising the following steps:

[0007] Disperse an iodine salt in water solvent A to obtain solution A;

[0008] Disperse graphene oxide in water solvent B to obtain solution B;

[0009] Disperse bismuth source and zirconium source in an organic solvent, and perform a first stirring treatment at 30-90 °C to obtain solution C; and under this stirring action, add the solution B to the solution C to obtain solution D;

[0010] Add the solution A to the solution D, adjust the pH to 10, perform a second stirring treatment, cool to room temperature, filter, wash, dry and grind to obtain the Zr-BiOI / GO composite material.

[0011] Preferably, the iodide salt is one or more of potassium iodide, sodium iodide, and calcium iodide;

[0012] The bismuth source is one or more of bismuth nitrate, bismuth sulfate, and bismuth chloride;

[0013] The zirconium source is one or more of zirconium oxychloride, zirconium nitrate, and zirconium tetrachloride.

[0014] Preferably, the organic solvent is one or more of ethylene glycol, ethanol, and glycerol;

[0015] And the dosage ratio of the organic solvent to the bismuth source and zirconium source is 50 mL: 1-4 mmol: 0.01-0.2 mmol.

[0016] Preferably, the molar ratio of the iodide salt in the solution A to the bismuth source in the solution D is 1-6: 1-4.

[0017] Preferably, the dosage ratio of graphene oxide in the solution B to the bismuth source in the solution C is 0.01-0.03 g: 1-4 mmol.

[0018] Preferably, the dosage ratio of the iodide salt to the water solvent A is 1-6 mmol: 30 mL;

[0019] The dosage ratio of graphene oxide to the water solvent B is 0.01-0.03 g: 50 mL.

[0020] Preferably, pump the solution A into the solution D through a peristaltic pump, and the pumping rate is 1-4 r / min.

[0021] Preferably, the stirring rate of the first stirring treatment is 200-300 r / min, and the stirring time is 10-30 min;

[0022] The stirring rate of the second stirring treatment is 200-300 r / min, and the stirring time is 1-4 h.

[0023] The second object of the present invention is to provide a Zr-BiOI / GO composite material prepared by the above preparation method.

[0024] The third object of the present invention is to provide an application of the above Zr-BiOI / GO composite material in photocatalytic degradation of organic pollutants in wastewater.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention uses a hydrolysis method to prepare a Zr-BiOI / GO composite photocatalytic material. GO, as a carrier, provides a large number of binding sites and promotes the rapid transport of carriers; BiOI, as a semiconductor with a relatively narrow bandgap, has good visible light response performance. After hydrothermal compounding, no new phase appears in the Zr doping, and the sample retains the crystal phase structure of the original BiOI. It is possible that Zr enters the BiOI lattice to form a substitutional solid solution. In the prepared Zr-BiOI / GO composite photocatalytic material system, electrons (e - ) quickly move from BiOI to Zr, inducing a reduction reaction; holes (h + ) can migrate to the surface of BiOI, inducing an oxidation reaction. Electrons and holes can be effectively separated, and at the same time, the recombination of the two is inhibited, overcoming the deficiency that the photogenerated electron-hole pairs of single BiOI are easily recombined, and improving the photocatalytic activity.

[0027] The chemical reagents used in the present invention are easily available, and the preparation process is mild and simple, meeting the requirements of green development; the preparation method of the present invention has low cost, can greatly reduce the manufacturing cost, the prepared Zr-BiOI / GO composite photocatalytic material has an increased specific surface area, improved photocatalytic performance, enhanced utilization rate of visible light, and high removal efficiency for organic pollutants.

[0028] The Zr-BiOI / GO composite photocatalytic material prepared by the present invention has the characteristics of a large specific surface area, good photocatalytic performance, and high utilization rate of visible light. The preparation method is simple, the photocatalytic effect is good, and the production cost of the composite material is low. Description of the Drawings

[0029] Figure 1 SEM image of the nano BiOI photocatalytic material prepared in Comparative Example 1;

[0030] Figure 2 SEM image of the nano BiOI / GO photocatalytic material prepared in Comparative Example 4;

[0031] Figure 3 SEM image of the nano Zr-BiOI / GO photocatalytic material prepared in Example 1;

[0032] Figure 4TEM image of the nano - BiOI photocatalytic material prepared in Comparative Example 1;

[0033] Figure 5 TEM image of the nano - BiOI / GO photocatalytic material prepared in Comparative Example 4;

[0034] Figure 6 TEM image of the nano - Zr - BiOI / GO photocatalytic material prepared in Example 1;

[0035] Figure 7 XRD patterns of the nano - BiOI prepared in Comparative Example 1, the nano - BiOI / GO prepared in Comparative Example 4, and the nano - Zr - BiOI / GO composite photocatalytic material prepared in Example 1;

[0036] Figure 8 FT - IR spectra of the nano - BiOI prepared in Comparative Example 1, the nano - BiOI / GO prepared in Comparative Example 4, and the nano - Zr - BiOI / GO composite photocatalytic material prepared in Example 1;

[0037] Figure 9 UV - vis spectra of the nano - BiOI prepared in Comparative Example 1, the nano - BiOI / GO prepared in Comparative Example 4, and the nano - Zr - BiOI / GO composite photocatalytic material prepared in Example 1;

[0038] Figure 10 Photocatalytic degradation effect diagrams of the nano - BiOI prepared in Comparative Example 1, the nano - BiOI / GO prepared in Comparative Example 4, and the nano - Zr - BiOI / GO composite photocatalytic material prepared in Example 1. Detailed implementation manners

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0040] The present invention provides a Zr - BiOI / GO composite material, and its preparation method is as follows:

[0041] Disperse the iodine salt in the aqueous solvent A to obtain Solution A;

[0042] Disperse the graphene oxide in the aqueous solvent B to obtain Solution B;

[0043] Disperse the bismuth source and zirconium source in the organic solvent, and then perform the first stirring treatment at 30 - 90 °C to obtain Solution C; and under this stirring action, add Solution B to Solution C to obtain Solution D;

[0044] Add Solution A to Solution D, adjust the pH to 10, perform the second stirring treatment, cool to room temperature, filter, wash, dry and grind to obtain the Zr - BiOI / GO composite material.

[0045] It should be noted that considering the solubility differences among iodine salt, graphene oxide, bismuth source and zirconium source, in order to make each component fully mixed, preferably, the bismuth source used is bismuth nitrate pentahydrate, and the zirconium source is zirconium oxychloride. After forming solutions of iodine salt, graphene oxide, bismuth source and zirconium source respectively, they are then mixed for reaction to enable full reaction among the respective preparation raw materials to form Zr-BiOI / GO composite material.

[0046] Considering the factor of catalytic activity, the iodine salt used in the present invention is potassium iodide. Using water as the solvent, the iodine salt is dissolved in water alone, and the dosage ratio of the iodine salt to the water solvent A is 1-6 mmol: 30 mL to enable the iodine salt to be fully dissolved in water to form solvent A.

[0047] The present invention disperses graphene oxide alone in a water solvent to obtain solution B, and the dosage ratio of the graphene oxide to the water solvent B is 0.01-0.03 g: 50 mL. In order to make graphene oxide uniformly dispersed in water solvent B, the present invention preferably uses ultrasonic waves to uniformly disperse graphene oxide in water solvent B, and the ultrasonic frequency of the ultrasonic waves is 80-90 kHz, the ultrasonic power is 100-120 W, and the ultrasonic time is 20-40 min.

[0048] In order to enable the zirconium source to be uniformly doped into BiOI, the present invention preferably disperses the bismuth source and zirconium source together uniformly in an organic solvent to obtain a mixed solution of bismuth source and zirconium source; and the dosage ratio of the organic solvent to the bismuth source and zirconium source is 50 mL: 1-4 mmol: 0.01-0.2 mmol. In order to make the bismuth source and zirconium source uniformly dispersed in the organic solvent, the present invention preferably uses ultrasonic waves to disperse the bismuth source and zirconium source, and the ultrasonic frequency of the ultrasonic waves is 80-90 kHz, the ultrasonic power is 100-120 W, and the ultrasonic time is 10-30 min. In order to ensure that the bismuth source and zirconium source can be uniformly loaded on graphene oxide, so as to uniformly form Zr-BiOI on graphene oxide in the subsequent process and obtain a Zr-BiOI / GO composite material with uniform components, the present invention preferably performs a stirring treatment on the mixed solution of bismuth source and zirconium source after ultrasonic treatment to make each component fully mixed. At the same time, under this stirring action, the above-prepared solution B is added and mixed uniformly. Subsequently, continue to perform a stirring treatment to make graphene oxide in the solution uniformly dispersed, and the stirring rate is 200-300 r / min, and the stirring time is 10-30 min. Among them, the dosage ratio of graphene oxide in the solution B to the bismuth source in the solution C is 0.01-0.03 g: 1-4 mmol.

[0049] In order to enable the uniform formation of Zr-BiOI on graphene oxide, the present invention preferably slowly adds the above solution A to the above solution D, so that the iodide salt in solution A can fully react with the bismuth ions and zirconium ions supported on graphene oxide to form zirconium-doped BiOI, that is, a Zr-BiOI / GO composite material is obtained. And the molar ratio of the iodide salt in solution A to the bismuth source in solution D is 1-6:1-4. In order to ensure that solution A is slowly added to the above solution D, the present invention preferably pumps solution A into solution D through a peristaltic pump, and the pumping rate is 1-4 r / min. After the pumping is completed, the pH of the system is adjusted to 10 with 1 mol / L NaOH, and then a second stirring treatment is carried out to achieve the purpose of loading the zirconium source on GO. And the stirring rate of the second stirring treatment is 200-300 r / min, and the stirring time is 1-4 h. And the present invention uses deionized water and absolute ethanol as detergents to wash the filtered product after the above second stirring treatment, and at least washes 3 times to remove soluble impurities such as chloride ions. Then, through drying treatment, the washing solvent remaining on the surface of the product is removed, and the drying temperature is 60 °C, and the drying time is 8-12 h, that is, the Zr-BiOI / GO composite photocatalytic material of the present invention is obtained.

[0050] Example 1

[0051] This example provides a Zr-BiOI / GO composite photocatalytic material, and its preparation method is as follows:

[0052] 1) 0.166 g of potassium iodide was uniformly dispersed in 30 mL of deionized water to obtain solution A.

[0053] 2) 0.025 g of graphene oxide (GO) was placed in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated at room temperature for 20 min to uniformly disperse GO in deionized water to obtain solution B.

[0054] 3) 0.485 g of bismuth nitrate pentahydrate and 0.0322 g of zirconium oxychloride octahydrate were placed in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated for 20 min, and then placed in a water bath at 50 °C and stirred at a stirring rate of 250 r / min for 30 min to obtain solution C.

[0055] 4) The solution C was continuously stirred at the stirring rate of step 3) above, and under this stirring action, the above solution B was added. After the addition was completed, it was continuously stirred for 30 min to obtain solution D.

[0056] 5) Using a peristaltic pump at 2 r / min, slowly pump the solution A prepared in step 1) above into the solution D in step 4) above. After the addition is completed, adjust the pH value to 10 with 1 mol / L NaOH, then stir at a stirring rate of 250 r / min for 1 h. After the reaction is completed, cool to room temperature, wash 3 times with deionized water and anhydrous ethanol respectively, and dry in a blast drying oven at 60 °C for 12 h to obtain the Zr-BiOI / GO composite photocatalytic material.

[0057] Example 2

[0058] This example provides a Zr-BiOI / GO composite photocatalytic material, and its preparation method is as follows:

[0059] 1) Uniformly disperse 0.232 g of potassium iodide in 30 mL of deionized water to obtain solution A.

[0060] 2) Place 0.01 g of graphene oxide (GO) in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonically treat at room temperature for 20 min to uniformly disperse GO in deionized water to obtain solution B.

[0061] 3) Place 0.970 g of bismuth nitrate pentahydrate and 0.0032 g of zirconium oxychloride octahydrate in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonically treat for 20 min, then place in a water bath at 30 °C and stir at a stirring rate of 250 r / min for 20 min to obtain solution C.

[0062] 4) Continue to stir solution C at the stirring rate in step 3) above, and under this stirring action, add solution B above. After the addition is completed, continue to stir for 30 min to obtain solution D.

[0063] 5) Using a peristaltic pump at 3 r / min, slowly pump the solution A prepared in step 1) above into the solution D in step 4) above. After the addition is completed, adjust the pH value to 10 with 1 mol / L NaOH, then stir at a stirring rate of 250 r / min for 4 h. After the reaction is completed, cool to room temperature, wash 3 times with deionized water and anhydrous ethanol respectively, and dry in a blast drying oven at 60 °C for 10 h to obtain the Zr-BiOI / GO composite photocatalytic material.

[0064] Example 3

[0065] This example provides a Zr-BiOI / GO composite photocatalytic material, and its preparation method is as follows:

[0066] 1) Uniformly disperse 0.996 g of potassium iodide in 30 mL of deionized water to obtain solution A.

[0067] 2) Place 0.03 g of graphene oxide (GO) in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonically treat at room temperature for 20 min to uniformly disperse GO in deionized water, obtaining solution B.

[0068] 3) Place 1.94 g of bismuth nitrate pentahydrate and 0.0483 g of zirconium oxychloride octahydrate in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonically treat for 20 min. Subsequently, place it in a water bath at 90 °C and stir at a stirring rate of 250 r / min for 10 min to obtain solution C.

[0069] 4) Continue to stir solution C at the stirring rate in step 3) above. Under this stirring action, add the above solution B. After the addition is completed, continue to stir for 30 min to obtain solution D.

[0070] 5) Slowly pump solution A prepared in step 1) above into solution D in step 4) at 2 r / min through a peristaltic pump. After the addition is completed, adjust the pH value to 10 with 1 mol / L NaOH. Subsequently, stir at a stirring rate of 250 r / min for 2 h. After the reaction is completed, cool to room temperature, wash 3 times with deionized water and anhydrous ethanol respectively, and dry in a blast drying oven at 60 °C for 11 h to obtain the Zr - BiOI / GO composite photocatalytic material.

[0071] Comparative Example 1

[0072] This comparative example provides a BiOI photocatalytic material, and its preparation method is as follows:

[0073] 1) Uniformly disperse 0.166 g of potassium iodide in 30 mL of deionized water to obtain solution A.

[0074] 2) Place 0.485 g of bismuth nitrate pentahydrate in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonically treat for 20 min. Subsequently, place it in a water bath at 50 °C and stir at a stirring rate of 250 r / min for 30 min to obtain solution C.

[0075] 3) Slowly pump solution A prepared in step 1) above into solution C in step 2) at 2 r / min through a peristaltic pump. After the addition is completed, stir at a stirring rate of 250 r / min for 1 h. After the reaction is completed, cool to room temperature, wash 3 times with deionized water and anhydrous ethanol respectively, and dry in a blast drying oven at 60 °C for 12 h to obtain the BiOI photocatalytic material.

[0076] That is, the difference between this comparative example and Example 1 is that this comparative example does not add graphene oxide and zirconium source.

[0077] Comparative Example 2

[0078] This comparative example provides a BiOI photocatalytic material, and its preparation method is as follows:

[0079] 1) 0.232 g of potassium iodide was uniformly dispersed in 30 mL of deionized water to obtain solution A.

[0080] 2) 0.970 g of bismuth nitrate pentahydrate was placed in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated for 20 min. Subsequently, it was placed in a water bath at 30 °C and stirred at a stirring rate of 250 r / min for 20 min to obtain solution C.

[0081] 3) Through a peristaltic pump at 3 r / min, the solution A prepared in the above step 1) was slowly pumped into the solution C in the above step 2). After the addition was completed, it was stirred at a stirring rate of 250 r / min for 4 h. After the reaction ended, it was cooled to room temperature, washed 3 times with deionized water and anhydrous ethanol respectively, and dried in a blast drying oven at 60 °C for 10 h to obtain the BiOI photocatalytic material.

[0082] That is, the difference between this comparative example and Example 2 is that this comparative example does not add graphene oxide and zirconium source.

[0083] Comparative Example 3

[0084] This comparative example provides a BiOI photocatalytic material, and its preparation method is as follows:

[0085] 1) 0.996 g of potassium iodide was uniformly dispersed in 30 mL of deionized water to obtain solution A.

[0086] 2) 1.94 g of bismuth nitrate pentahydrate was placed in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated for 20 min. Subsequently, it was placed in a water bath at 90 °C and stirred at a stirring rate of 250 r / min for 10 min to obtain solution C.

[0087] 3) Through a peristaltic pump at 4 r / min, the solution A prepared in the above step 1) was slowly pumped into the solution C in the above step 2). After the addition was completed, it was stirred at a stirring rate of 250 r / min for 2 h. After the reaction ended, it was cooled to room temperature, washed 3 times with deionized water and anhydrous ethanol respectively, and dried in a blast drying oven at 60 °C for 11 h to obtain the BiOI photocatalytic material.

[0088] That is, the difference between this comparative example and Example 3 is that this comparative example does not add graphene oxide and zirconium source.

[0089] Comparative Example 4

[0090] This comparative example provides a BiOI / GO photocatalytic material, and its preparation method is as follows:

[0091] 1) 0.166 g of potassium iodide was uniformly dispersed in 30 mL of deionized water to obtain solution A.

[0092] 2) 0.025 g of graphene oxide (GO) was placed in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated at room temperature for 20 min to uniformly disperse GO in deionized water, obtaining solution B.

[0093] 3) 0.485 g of bismuth nitrate pentahydrate was placed in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated for 20 min, and then placed in a water bath at 50 °C and stirred at a stirring rate of 250 r / min for 30 min to obtain solution C.

[0094] 4) Solution C was continuously stirred at the stirring rate of step 3) above, and under this stirring action, solution B was added. After the addition was completed, stirring was continued for 30 min to obtain solution D.

[0095] 5) Solution A prepared in step 1) above was slowly pumped into solution D of step 4) at 2 r / min through a peristaltic pump. After the addition was completed, it was stirred at a stirring rate of 250 r / min for 1 h. After the reaction ended, it was cooled to room temperature, washed 3 times with deionized water and anhydrous ethanol respectively, and dried in a blast drying oven at 60 °C for 12 h to obtain the BiOI / GO composite photocatalytic material.

[0096] That is, the difference between this comparative example and Example 1 is that this comparative example does not add a zirconium source.

[0097] Comparative Example 5

[0098] This comparative example provides a BiOI / GO photocatalytic material, and its preparation method is as follows:

[0099] 1) 0.232 g of potassium iodide was uniformly dispersed in 30 mL of deionized water to obtain solution A.

[0100] 2) 0.01 g of graphene oxide (GO) was placed in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, it was ultrasonically treated at room temperature for 20 min to uniformly disperse GO in deionized water, obtaining solution B.

[0101] 3) Place 0.970 g of bismuth nitrate pentahydrate in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonicate for 20 min. Then place it in a water bath at 30 °C and stir at a stirring rate of 250 r / min for 20 min to obtain Solution C.

[0102] 4) Continue to stir Solution C at the stirring rate in Step 3) above. Under this stirring action, add the above Solution B. After the addition is complete, continue to stir for 30 min to obtain Solution D.

[0103] 5) Slowly pump Solution A prepared in Step 1) above into Solution D in Step 4) at 3 r / min through a peristaltic pump. After the addition is complete, stir at a stirring rate of 250 r / min for 4 h. After the reaction is completed, cool to room temperature, wash three times with deionized water and anhydrous ethanol respectively, and dry in a blast drying oven at 60 °C for 10 h to obtain the BiOI / GO composite photocatalytic material.

[0104] That is, the difference between this comparative example and Example 2 is that this comparative example does not add a zirconium source.

[0105] Comparative Example 6

[0106] This comparative example provides a BiOI / GO photocatalytic material, and its preparation method is as follows:

[0107] 1) Uniformly disperse 0.996 g of potassium iodide in 30 mL of deionized water to obtain Solution A.

[0108] 2) Place 0.03 g of graphene oxide (GO) in 50 mL of deionized water, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonicate at room temperature for 20 min to uniformly disperse GO in deionized water to obtain Solution B.

[0109] 3) Place 1.94 g of bismuth nitrate pentahydrate in 50 mL of ethylene glycol, and under ultrasonic conditions with an ultrasonic frequency of 85 kHz and a power of 110 W, ultrasonicate for 20 min. Then place it in a water bath at 90 °C and stir at a stirring rate of 250 r / min for 10 min to obtain Solution C.

[0110] 4) Continue to stir Solution C at the stirring rate in Step 3) above. Under this stirring action, add the above Solution B. After the addition is complete, continue to stir for 30 min to obtain Solution D.

[0111] 5) The solution A prepared in the above step 1) was slowly pumped into the solution D in the above step 4) by a peristaltic pump at 2 r / min. After the addition was completed, the solution was stirred at a stirring rate of 250 r / min for 2 h. After the reaction was completed, it was cooled to room temperature, washed with deionized water and anhydrous ethanol for 3 times respectively, and dried in a 60° C. forced air drying oven for 11 h to obtain a BiOI / GO composite photocatalytic material.

[0112] That is, the difference between this comparative example and Example 3 is that no zirconium source is added in this comparative example.

[0113] Experimental part

[0114] (I) Morphology test analysis

[0115] 1) SEM test

[0116] The present invention takes Comparative Example 1, Comparative Example 4 and Example 1 as examples, and performs SEM tests on them respectively, and the test results are as follows: Figure 1 , Figure 2 and Figure 3 shown.

[0117] in, Figure 1 This is a SEM image of the BiOI photocatalytic material prepared in Comparative Example 1, and it can be seen that the BiOI is spherical, has a smooth surface, and has a certain thickness, similar to a petal shape, so the prepared BiOI structure is called a microsphere flower-like structure.

[0118] Figure 2 This is the SEM image of the BiOI / GO composite photocatalytic material prepared in Comparative Example 4, and it can be seen that

[0119] BiOI / GO presents an obvious layered structure, which is determined by the inherent properties of graphene oxide, and more BiOI can be observed on the surface of the layer.

[0120] Figure 3 This is the SEM image of the Zr-BiOI / GO composite photocatalytic material prepared in Example 1. It can be seen that nanoparticles are evenly covered on the surface of the GO sheet. At the same time, Zr-BiOI / GO still presents a layered structure like BiOI, indicating that after doping and composite, the material still has the layered structure of BiOI, the particle size is reduced, and it is a nano-scale material.

[0121] 2) TEM test

[0122] The present invention takes Comparative Example 1, Comparative Example 4 and Example 1 as examples, and TEM tests are performed on them respectively, and the test results are as follows: Figure 4 , Figure 5 and Figure 6 shown.

[0123] Among them, Figure 4 is the TEM image of the BiOI photocatalytic material prepared in Comparative Example 1. It can be seen that the nano-BiOI presents a large particle morphology, with a high degree of overlap and serious agglomeration.

[0124] Figure 5 is the TEM image of the BiOI / GO composite photocatalytic material prepared in Comparative Example 4. It can be seen that the prepared material better retains the lamellar structure of graphene oxide. It can be seen that BiOI is loaded on the surface, and the particle size is relatively uniform.

[0125] Figure 6 is the TEM image of the Zr-BiOI / GO composite photocatalytic material prepared in Example 1. It can be seen that in Zr-BiOI / GO, BiOI and the composite GO present a sheet structure, enabling BiOI to be well dispersed, increasing the specific surface area, and thus exposing more photocatalytic active sites. It can also be seen that there are dot-like substances generated on the material surface, which may be the Zr(OH)4 precipitate formed by the partially doped Zr on the surface, indicating that the Zr element has been successfully doped into the material.

[0126] (2) XRD test

[0127] In this invention, taking Comparative Example 1, Comparative Example 4 and Example 1 as examples, XRD tests were respectively carried out on them, and the test results are as Figure 7 shown.

[0128] And from Figure 7 it can be seen that the diffraction peaks of nano-BiOI correspond to the (001), (102), (110), (200), (114), (212) crystal planes, which are consistent with the BiOI card JCPDS No.10-0445 of the tetragonal phase. For Zr-BiOI / GO, no characteristic peaks of graphene oxide were observed. This may be due to the partial amorphousness of graphene oxide, resulting in defects in the graphene oxide film and losing its crystallinity. No new phase appears due to zirconium doping, and the sample retains the original crystal phase structure of BiOI. It may be that zirconium enters the BiOI lattice to form a substitutional solid solution.

[0129] (3) FT-IR test

[0130] In this invention, taking Comparative Example 1, Comparative Example 4 and Example 1 as examples, FT-IR tests were respectively carried out on them, and the test results are as Figure 8 shown.

[0131] And from Figure 8 it can be seen that in the Zr-BiOI / GO sample, at 3427 cm -1 and 1573 cm -1The absorption peaks appearing at [specific location] are caused by the stretching vibration peak and bending vibration peak of the -OH bond in the water molecules adsorbed on the catalyst surface; 2917 cm -1 and 1477 cm -1 The absorption peaks at [specific location] are attributed to the stretching vibration peak and bending vibration peak of the C-H bond in the hydrocarbons adsorbed on the catalyst surface; 1726 cm -1 The newly added absorption peak at [specific location] is the stretching vibration peak of the C=O bond in the carboxyl group and carbonyl group at the edge of the GO sheet; 1323 cm -1 The newly added absorption peak at [specific location] is the stretching vibration peak of the Zr-OH bond; 1005 cm -1 The newly added absorption peak at [specific location] is the stretching vibration peak of the C-C bond; 910 - 500 cm -1 The newly added absorption peak at [specific location] should be the stretching vibration peak of the Zr-O bond, indicating that part of the zirconium element has been successfully doped into the BiOI lattice; 452 cm -1 The absorption peak at [specific location] is the stretching vibration peak of the Bi-O bond. The above results show that the prepared Zr-BiOI / GO has the target structure.

[0132] (IV) UV-vis Test

[0133] In this invention, taking Comparative Example 1, Comparative Example 4 and Example 1 as examples, UV-vis tests were respectively carried out on them, and the test results are as Figure 9 shown.

[0134] And it can be seen from Figure 9 that the absorption edges of the materials are all in the visible light region. Compared with pure BiOI, the optical absorption edge of Zr-BiOI / GO shifts towards a larger wavelength. According to the tangent method, the optical absorption thresholds of BiOI and Zr-BiOI / GO can be obtained, which are 640.6 nm and 726.4 nm respectively. According to the calculation formula of the band gap energy E g = 1240 / λ g , it can be calculated that the band gap energy of BiOI is about 1.94 eV, while that of Zr-BiOI / GO is 1.71 eV. The decrease in the band gap energy can absorb and utilize more visible light, generate more photo-generated electron-hole pairs, thereby improving the visible light response range of the catalyst and the performance of the material in photocatalytic degradation of pollutants.

[0135] (V) Photocatalytic Degradation Effect

[0136] In this invention, taking Comparative Example 1, Comparative Example 4 and Example 1 as examples, photocatalytic degradation effect tests were respectively carried out on them, and the test results are as Figure 10 shown.

[0137] And it can be seen from Figure 10It can be seen that the CR solution without the addition of photocatalytic material has almost no photocatalytic degradation effect under visible light (the curve of the blank control can be ignored). The degradation rates of CR by BiOI, BiOI / GO, and Zr-BiOI / GO are 33.82%, 67.74%, and 95.42% respectively. The results show that by adding zirconium elements, the removal rate of the composite material for CR increases rapidly, indicating that Zr (p-type semiconductor) effectively reduces the recombination of photogenerated electron-hole pairs, thereby increasing the carrier lifetime. In addition, the incorporation of Zr in BiOI increases the specific surface area and promotes the transfer of photogenerated charges, greatly improving the photocatalytic degradation efficiency.

[0138] (VI) Removal effect on organic pollutants in wastewater

[0139] In this invention, a Congo red solution containing 40 mg / L is used to simulate organic pollutants in wastewater. The materials prepared in Comparative Example 1, Comparative Example 4, and Example 1 are used as photocatalysts, and the removal effect on Congo red in the Congo red solution is tested according to the following method:

[0140] Weigh 10 mg of BiOI in Comparative Example 1, 10 mg of BiOI / GO in Comparative Example 4, and 10 mg of Zr-BiOI / GO in Example 1, and place them respectively in 100 mL of Congo red solution containing 40 mg / L. Stir in the dark at 25 °C for 0.5 h, irradiate and stir with an LED lamp for 2 h, filter with a 0.45 μm microfiltration membrane to obtain a clear liquid, and use an ultraviolet spectrophotometer to measure the absorbance of the Congo red solution at 497 nm. The results are shown in Table 1.

[0141] Table 1 Detection and analysis results of samples

[0142]

[0143] As can be seen from Table 1, the Zr-BiOI / GO composite material has a better effect on removing organic wastewater than the photocatalytic effect of nano-BiOI. The specific surface areas of the modified materials all increase, improving the contact with pollutants and facilitating the photocatalytic process.

[0144] Obviously, the above embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A preparation method of a Zr-BiOI / GO composite material, characterized in that, Including the following steps: Disperse the iodized salt in the aqueous solvent A to obtain solution A; Disperse graphene oxide in the aqueous solvent B to obtain solution B; Disperse the bismuth source and zirconium source in an organic solvent, and perform a first stirring treatment at 30-90 °C to obtain solution C; And under this stirring action, add the solution B to the solution C to obtain solution D; Add the solution A to the solution D, adjust the pH to 10, perform a second stirring treatment, cool to room temperature, filter, wash, dry and grind to obtain the Zr-BiOI / GO composite material.

2. The preparation method according to claim 1, characterized in that, The iodized salt is one or more of potassium iodide, sodium iodide, and calcium iodide; The bismuth source is one or more of bismuth nitrate, bismuth sulfate, and bismuth chloride; The zirconium source is one or more of zirconium oxychloride, zirconium nitrate, and zirconium tetrachloride.

3. The preparation method according to claim 1, characterized in that, The organic solvent is one or more of ethylene glycol, ethanol, and glycerol. And the dosage ratio of the organic solvent to the bismuth source and zirconium source is 50 mL: 1-4 mmol: 0.01-0.2 mmol.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the iodized salt in the solution A to the bismuth source in the solution D is 1-6: 1-4.

5. The preparation method according to claim 1, characterized in that The dosage ratio of graphene oxide in the solution B to the bismuth source in the solution C is 0.01-0.03 g: 1-4 mmol.

6. The preparation method according to claim 1, characterized in that, The dosage ratio of the iodized salt to the aqueous solvent A is 1-6 mmol: 30 mL; The dosage ratio of graphene oxide to the aqueous solvent B is 0.01-0.03 g: 50 mL.

7. The preparation method according to claim 1, characterized in that Pump the solution A into the solution D through a peristaltic pump, and the pumping rate is 1-4 r / min.

8. The preparation method according to claim 1, characterized in that, The stirring rate of the first stirring treatment is 200-300 r / min, and the stirring time is 10-30 min; The stirring rate of the second stirring treatment is 200-300 r / min, and the stirring time is 1-4 h.

9. A Zr-BiOI / GO composite material prepared by the preparation method according to any one of claims 1-8.

10. An application of the Zr-BiOI / GO composite material according to claim 9 in photocatalytic degradation of organic pollutants in wastewater.

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