CN102489290A - Preparation method of nano bismuth vanadate photocatalyst loaded on active carbon fiber - Google Patents

Abstract

The invention relates to a preparation method of activated carbon fiber loaded nano bismuth vanadate photocatalyst, comprising: (1) adding bismuth salt and stabilizer to phosphate buffer, stirring to form a suspension; dissolving metavanadate in Phosphate buffer, then added to the above suspension, stirred evenly to form a transparent solution; (2) Adjust the pH of the above transparent solution to 6.0-8.0 with an alkaline solution, and then add the active Carbon fiber, stirred until evenly mixed, then centrifuged, filtered, washed, then put into a muffle furnace for roasting, and finally cooled and ground to obtain the product. The preparation method of the present invention is simple and easy, has low requirements on equipment, and has good operability; the activated carbon fiber powder bismuth vanadate prepared by the present invention is evenly loaded, and can efficiently degrade persistent toxic and harmful substances under the conditions of ultraviolet light and visible light. Simple and recyclable.

Description

A kind of preparation method of activated carbon fiber loaded nano bismuth vanadate photocatalyst

technical field

The invention belongs to the field of preparation of nano bismuth vanadate photocatalyst, in particular to a preparation method of activated carbon fiber loaded nano bismuth vanadate photocatalyst.

Background technique

In recent years, the photocatalytic technology represented by titanium dioxide (TiO ₂ ) has been widely used in the field of environmental pollution control, especially in the treatment of refractory biodegradable wastewater and air purification. However, due to its wide band gap, only It can only have photocatalysis under the irradiation of ultraviolet light, which limits the further expansion of its application field. In order to improve _the utilization efficiency of TiO ₂ to sunlight, many experts and scholars at home and abroad have carried out a lot of research work on TiO ₂ photocatalysts responding to visible light. Hybrid modification, etc., aiming to expand its spectral response range and improve its visible light catalytic activity. Nevertheless, the modified _TiO2 photocatalysts still have problems such as unsatisfactory visible light catalytic activity and poor photodegradation ability at the current stage, which lead to their poor practicability.

Recent studies have found that bismuth vanadate (BiVO ₄ ), a compound oxide with a monoclinic scheelite structure, has photocatalytic activity under visible light irradiation, and can decompose water molecules to produce oxygen and degrade organic pollutants. potential photocatalyst. However, the adsorption performance of BiVO ₄ is poor, and the generated photogenerated carriers are difficult to migrate and easy to recombine, which affects its visible light activity. At present, there are few research reports on the compound modification and doping of BiVO ₄ , and there are not many reports on loading it on porous materials with good adsorption properties, such as activated carbon. Therefore, how to enhance its performance in the visible light range Absorption, as well as improving its catalytic activity under visible light, are the main research focuses in the current research and development of _BiVO4 high-efficiency photocatalysts.

The conventional methods of sewage treatment mainly include: physical separation method, biodegradation method, chemical decomposition method, etc., but these methods have certain limitations. Therefore, researchers have begun to work on the development of high efficiency, low energy consumption, wide application range and deep oxidation Capable water purification technology. In recent years, many scholars have used TiO ₂ for photocatalytic degradation of organic pollutants in water bodies. Although some effects have been achieved, the treatment effect is often not ideal due to the limitation of its photoresponse range.

Contents of the invention

The technical problem to be solved by the present invention is to provide a preparation method of activated carbon fiber-loaded nano-bismuth vanadate photocatalyst. The method is simple and easy to operate, and has low requirements on equipment. Efficiently degrade persistent toxic and harmful substances under light and visible light conditions.

A kind of preparation method of activated carbon fiber loaded nano-bismuth vanadate photocatalyst of the present invention comprises:

(1) Add bismuth salt and stabilizer to phosphate buffer, stir to form a suspension; dissolve metavanadate in phosphate buffer, then add to the above suspension, stir evenly, and form a transparent Solution; wherein the molar concentration of bismuth salt and metavanadate is 0.05-0.25 mol/L, and the molar concentration of stabilizer is 0.01-0.05 mol/L;

(2) Adjust the pH value of the above-mentioned transparent solution to 6.0 to 8.0 with an alkaline solution, then add activated carbon fiber at 40 to 100 ° C, stir until evenly mixed, then centrifuge, filter, and wash, then put it in a muffle furnace, Calcined at 250-400°C for 3-6 hours, and finally cooled and ground to obtain the product; the mass ratio of activated carbon fiber to bismuth salt is 2-10:1.

The stirring time in the step (1) to form the suspension by stirring is 30 to 60 minutes.

The bismuth salt described in step (1) is bismuth nitrate, bismuth chloride or bismuth acetate.

The stabilizer described in step (1) is sodium gluconate, disodium edetate or butane tetracarboxylic acid.

The metavanadate described in step (1) is sodium metavanadate, potassium metavanadate or ammonium metavanadate.

The molar ratio of bismuth salt and metavanadate described in step (1) is 1:1.

The phosphate buffer solution described in the step (1) is composed of potassium dihydrogen phosphate and 0.035mol/L sodium hydroxide with a substance concentration of 0.05mol/L.

The alkaline solution described in step (2) is an aqueous solution of sodium hydroxide or potassium hydroxide with a concentration of 1.0 mol/L-3.0 mol/L.

Activated carbon fiber itself is a kind of adsorbent with good performance. It has the characteristics of large specific surface area and strong adsorption capacity. It can also achieve the beneficial effect of adsorbing and removing inorganic pollutants such as heavy metal ions in water treatment applications. The present invention utilizes the characteristics of the unique layered hollow structure, large specific surface area, and strong adsorption capacity of activated carbon fibers, and combines the visible light catalytic activity of BiVO ₄ to successfully load nano-BiVO ₄ onto activated carbon fibers to prepare a visible light active carbon fiber with high catalytic activity. Responsive photocatalytic materials, and applying them to the advanced treatment of biologically refractory wastewater, can achieve efficient removal of organic pollutants in water, especially for persistent micro-pollutants that are difficult to effectively remove by conventional treatment, and without secondary pollution question.

Beneficial effect

(1) The preparation method of the present invention is simple and easy, has low requirements on equipment, and has good operability;

(2) The activated carbon fiber powder prepared by the invention is evenly loaded with bismuth vanadate, can efficiently degrade persistent toxic and harmful substances under the conditions of ultraviolet light and visible light, and is easy to use and recyclable.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

(1) Add bismuth nitrate and disodium edetate into the phosphate buffer, and stir magnetically for 30 minutes to form a suspension; dissolve sodium metavanadate evenly in the phosphate buffer, and then add it dropwise to the In the above-mentioned suspension, the constant magnetic stirring is uniform to form a transparent solution; wherein the molar concentration of bismuth nitrate and sodium metavanate is 0.05mol/L, and the molar concentration of disodium edetate is 0.01mol/L. L, phosphate buffer saline is made up of potassium dihydrogen phosphate and 0.035mol/L sodium hydroxide that the concentration of substance is 0.05mol/L;

(2) Adopt the sodium hydroxide solution that concentration is 1.0mol/L to adjust the pH value of above-mentioned transparent solution to be 6.0, then add activated carbon fiber at 40 ℃, the mass ratio of bismuth nitrate and activated carbon fiber is 1: 2, continuous magnetic stirring Mix, centrifuge, filter, wash, put into muffle furnace, bake at 250°C for 3 hours, cool and grind, and then get activated carbon fiber photocatalyst powder loaded with nano-bismuth vanadate.

Example 2

(1) Add bismuth acetate and butane tetracarboxylic acid into the phosphate buffer, and stir magnetically for 45 minutes to form a suspension; dissolve potassium metavanadate evenly in the phosphate buffer, and then add it dropwise to the above suspension In the turbid liquid, the magnetic stirring is continued to form a transparent solution; the concentration of bismuth acetate and potassium metavanadate is 0.15mol/L, the concentration of butane tetracarboxylic acid is 0.025mol/L, and the concentration of phosphate buffer The liquid is composed of potassium dihydrogen phosphate with a concentration of 0.05mol/L and sodium hydroxide with a concentration of 0.035mol/L;

(2) The pH value of the above-mentioned transparent solution is adjusted to 7.0 by using a sodium hydroxide aqueous solution with a concentration of 2.0mol/L, and then adding activated carbon fibers at 70°C, the mass ratio of bismuth acetate to activated carbon fibers is 1: 5, and the magnetic stirring is continued Mix, centrifuge, filter, wash, put into muffle furnace, bake at 320°C for 5h, cool and grind, then get activated carbon fiber photocatalyst powder loaded with nano-bismuth vanadate.

Example 3

(1) Add bismuth chloride and sodium gluconate to the phosphate buffer, stir magnetically for 60 minutes to form a suspension; dissolve ammonium metavanadate evenly in the phosphate buffer, and then add it dropwise to the above suspension In the solution, the magnetic force is constantly stirred to form a transparent solution; wherein the molar concentration of bismuth chloride and ammonium metavanadate is 0.25mol/L, the molar concentration of sodium gluconate is 0.05mol/L, and the phosphate buffer is composed of The concentration of the substance is composed of potassium dihydrogen phosphate of 0.05mol/L and sodium hydroxide of 0.035mol/L;

(2) Use potassium hydroxide aqueous solution with a concentration of 3.0mol/L to adjust the pH value of the above-mentioned transparent solution to 8.0, then add activated carbon fiber at 100°C, the mass ratio of bismuth chloride and activated carbon fiber is 1: 10, continuous magnetic force Stir and mix, centrifuge, filter, wash, put into a muffle furnace, bake at 400°C for 6 hours, cool and grind, and then get activated carbon fiber photocatalyst powder loaded with nano-bismuth vanadate.

Example 4

Wastewater treatment experiment: take the mixed printing and dyeing wastewater finally discharged from a printing and dyeing factory as the treatment object, after pretreatment by microfiltration membrane filtration, add the same amount of photocatalysts prepared in Examples 1 to 3, and continuously After 4 hours of light irradiation, the decolorization rate and COD _Cr removal rate of printing and dyeing wastewater are shown in the following table:

Decolorization rate COD _Cr removal rate Example 1 95.2% 91.1% Example 2 99.1% 97.7% Example 3 98.5% 96.1%

Claims (8)

1. A preparation method of activated carbon fiber loaded nano bismuth vanadate photocatalyst, comprising: (1) Add bismuth salt and stabilizer to phosphate buffer, stir to form a suspension; dissolve metavanadate in phosphate buffer, then add to the above suspension, stir evenly, and form a transparent Solution; wherein the molar concentration of bismuth salt and metavanadate is 0.05-0.25 mol/L, and the molar concentration of stabilizer is 0.01-0.05 mol/L; (2) Adjust the pH value of the above-mentioned transparent solution to 6.0 to 8.0 with an alkaline solution, then add activated carbon fiber at 40 to 100 ° C, stir until evenly mixed, then centrifuge, filter, and wash, then put it in a muffle furnace, Calcined at 250-400°C for 3-6 hours, and finally cooled and ground to obtain the product; the mass ratio of activated carbon fiber to bismuth salt is 2-10:1. 2. The preparation method of a kind of activated carbon fiber-loaded nano-bismuth vanadate photocatalyst according to claim 1, characterized in that: the stirring time in the stirring to form the suspension described in step (1) is 30-60min. 3. The preparation method of a kind of activated carbon fiber supported nano-bismuth vanadate photocatalyst according to claim 1, characterized in that: the bismuth salt described in step (1) is bismuth nitrate, bismuth chloride or bismuth acetate. 4. the preparation method of a kind of activated carbon fiber supported nano-bismuth vanadate photocatalyst according to claim 1, is characterized in that: the stabilizing agent described in step (1) is sodium gluconate, disodium edetate or butane tetracarboxylic acid. 5. the preparation method of a kind of activated carbon fiber supported nano bismuth vanadate photocatalyst according to claim 1, is characterized in that: the metavanadate described in step (1) is sodium metavanadate, potassium metavanadate or ammonium metavanadate. 6. the preparation method of a kind of activated carbon fiber supported nano bismuth vanadate photocatalyst according to claim 1, is characterized in that: the mol ratio of bismuth salt described in step (1) and metavanadate is 1: 1 . 7. the preparation method of a kind of activated carbon fiber supported nano-bismuth vanadate photocatalyst according to claim 1, is characterized in that: the phosphate buffer solution described in step (1) is 0.05mol/L by the amount concentration of substance Potassium dihydrogen phosphate and 0.035mol/L sodium hydroxide. 8. The preparation method of a kind of activated carbon fiber supported nano-bismuth vanadate photocatalyst according to claim 1, characterized in that: the alkaline solution described in step (2) has a concentration of 1.0mol/L～3.0mol/L Aqueous sodium hydroxide or potassium hydroxide solution.