CN101920991A - A kind of method for preparing nano titanium dioxide - Google Patents

Abstract

The invention discloses a method for preparing nano-titanium dioxide with good photocatalytic activity by using industrial-grade titanium acetylacetonate as a titanium source, and belongs to the technical field of nano-titanium dioxide preparation. The present invention prepares nano-scale amorphous titanium dioxide by hydrolyzing titanium acetylacetonate under hydrothermal conditions, and puts it in a muffle furnace for calcination to convert it into anatase type, and proves the prepared by photocatalytic degradation dye experiment Titanium dioxide has good photocatalytic activity. The preparation process of the present invention is simple and convenient, and the cost is low, and it is easy to carry out large-scale production.

Description

A kind of method for preparing nano titanium dioxide

technical field

The invention relates to a method for preparing nano-titanium dioxide by using industrial-grade titanium acetylacetonate as a titanium source, in particular a method for preparing nano-titanium dioxide with simple preparation process, low cost and good photocatalytic activity.

Background technique

As a green, stable and efficient semiconductor photocatalyst, titanium dioxide is widely used in the treatment of inorganic wastewater and the degradation of organic matter. Among the three crystal forms of titanium dioxide, the anatase type has become the main choice for people to prepare photocatalysts due to its good photoelectric properties, and the simple preparation process, clean, non-toxic and non-secondary pollution manufacturing raw materials are suitable for large-scale production. Equipment requirements have become the main goal pursued by producers of titanium dioxide photocatalytic preparations. At present, the titanium sources used to prepare nano-titanium dioxide are mainly butyl titanate, titanium tetrachloride, titanyl sulfate, etc., and the synthesis methods are mainly sol-gel and hydrothermal methods. In the US5330953 patent, anatase-type nano-titanium dioxide was hydrothermally synthesized using titanyl sulfate as a titanium source. Sugimoto et al. (Colloid Interface Sci. 2003, 259 (1): 53-61.) used the sol-gel method to prepare nano-titanium dioxide with different shapes and sizes by changing the type of amine added and adjusting the pH value. Jun et al. (J.Am.Chem.Soc., 2003, 125:15981-15985.) used a non-hydrolytic sol-gel process to prepare spherical and rod-shaped nano-titanium dioxide with good dispersion through a surface-active selective agent. Ding et al. (J.Am.Chem.Soc., 2007, 129:6362-6363.) synthesized high-quality anatase nano-titanium dioxide in ionic liquid by microwave method using titanium isopropoxide as a precursor.

Titanium acetylacetonate is a chelate compound of titanium and acetylacetone, which is mainly used as a modifier for coatings, inks, varnishes and other products; curing accelerators, surface treatment agents, tackifiers, etc. So far, no one has been found to use titanium acetylacetonate as a titanium source to prepare nano-titanium dioxide. The chemical properties of titanium acetylacetonate are relatively stable, the price is low, and the toxicity is low, and the preparation method of nano-titanium dioxide by using it as a titanium source is simple, and the obtained product has good photocatalytic activity, and is expected to be produced on a large scale.

Contents of the invention

The purpose of the invention is to provide a method for synthesizing nano-titanium dioxide with good photocatalytic activity by using a new industrial-grade titanium source.

The present invention is realized through the following steps:

(1) Dissolve titanium acetylacetonate in absolute ethanol, add concentrated hydrochloric acid, the volume ratio of titanium acetylacetonate and absolute ethanol is 1:8～1:12, the volume ratio of titanium acetylacetonate and concentrated hydrochloric acid is 3:1 ~5:1, magnetic stirring to mix the reaction solution evenly, pour the yellow transparent reaction solution into a hydrothermal kettle, obtain amorphous titanium dioxide powder after hydrothermal reaction, wash the product with absolute ethanol, centrifuge, and dry .

(2) The obtained amorphous nano titanium dioxide is placed in a muffle furnace for roasting.

(3) The temperature of the hydrothermal reaction in the present invention is at least 120° C., and the reaction time is more than 10 h.

(4) In the present invention, the calcination temperature is 300-600° C., and the calcination time is more than 3 hours.

(5) The nano-titanium dioxide powder prepared by the present invention is anatase type, complete crystallization, particle size less than 50nm, regular shape and good dispersibility.

(6) Use X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), automatic physical and chemical adsorption analyzer (BET) to measure the specific surface area in the isothermal adsorption mode to analyze the morphology and structure of the product, The photocatalytic degradation experiment was carried out with Rhodamine B solution as the target dye, and the absorbance was measured by UV-Vis spectrophotometer to evaluate its photocatalytic activity.

Description of drawings

Figure 1 is the XRD diffraction spectrum of the prepared nano titanium dioxide, in which the diffraction peaks are all characteristic diffraction peaks of anatase titanium dioxide.

Figure 2 is a scanning electron micrograph of the prepared nano-titanium dioxide.

Figure 3 is a transmission electron micrograph of the prepared nano-titanium dioxide.

Fig. 4 is a graph showing the time-degradation rate relationship of photocatalytic degradation of rhodamine B solution by nano-titanium dioxide at different calcination temperatures.

1. 500°C 2. 600°C 3. 400°C 4. 300°C

The preparation of embodiment 1 nano titanium dioxide

Add 2 mL of titanium acetylacetonate and 0.6 mL of concentrated hydrochloric acid to 20 mL of absolute ethanol, and stir with a magnetic force. After the reactants are evenly mixed, transfer the reaction solution into a 25 mL hydrothermal kettle, 120 ° C, 10 h.

The obtained product was washed with absolute ethanol, centrifuged, and dried in a constant temperature drying oven at 60°C.

The dried amorphous nano-titanium dioxide is put into a muffle furnace for roasting at temperatures of 300, 400, 500, and 600° C. respectively.

The characterization analysis of the nano-titanium dioxide obtained under the different calcination temperatures of embodiment 2

As shown in Figure 1, the nano-titanium dioxide obtained at different calcination temperatures all exhibited the characteristic diffraction peaks of anatase-type titanium dioxide, had no impurities, and had complete crystallization.

The following table shows the specific surface area of nano-titanium dioxide prepared at different calcination temperatures and the average particle size data of the product calculated by XRD patterns.

The photocatalytic activity experiment of the nano-titanium dioxide obtained under the different calcination temperature of embodiment 3

(1) Prepare a rhodamine B solution with a concentration of 10 μg/L, and place the prepared solution in a dark place.

(2) Weigh 0.1 g of titanium dioxide roasted at different temperatures, place them in photocatalytic reactors, add 100 mL of the target degradation solution prepared in step (1), stir magnetically for 30 minutes, and wait for the titanium dioxide to disperse evenly, turn on the water source, light source , for photocatalytic degradation experiments.

(3) Absorb the photocatalytic degradation liquid in the reactor every 30 minutes, and use it for the measurement of the ultraviolet-visible absorbance after centrifugation.

(4) It can be seen from Figure 4 that the prepared nano-titanium dioxide has excellent photocatalytic activity, especially the degradation rate of rhodamine B solution has exceeded 60% after the catalytic reaction of the sample at 500 ° C for 60 minutes, and the final degradation rate has reached 100% .

Claims (4)

1. A method for preparing nano-titanium dioxide, characterized in that: titanium acetylacetonate is used as the titanium source, dehydrated alcohol is the solvent, concentrated hydrochloric acid is the hydrolysis accelerator, hydrothermal reaction under normal pressure makes the titanium source hydrolyzed, after the reaction finishes, alcohol washing, centrifuging, drying, and roasting the obtained product to obtain nano titanium dioxide. 2. the method for preparing nano titanium dioxide as claimed in claim 1, is characterized in that: concrete steps are as follows: (1) Dissolve titanium acetylacetonate in absolute ethanol, add concentrated hydrochloric acid, the volume ratio of titanium acetylacetonate and absolute ethanol is 1:8～1:12, the volume ratio of titanium acetylacetonate and concentrated hydrochloric acid is 3:1 ~5:1, magnetic stirring to mix the reaction solution evenly, pour the yellow transparent reaction solution into a hydrothermal kettle for hydrothermal reaction, the temperature of the hydrothermal reaction is at least 120°C, the reaction time is more than 10h, after the hydrothermal reaction Obtain amorphous titanium dioxide powder, wash the product with absolute ethanol, centrifuge, and dry; (2) Calcining the obtained amorphous nano titanium dioxide, the calcining temperature is 300-600° C., and the calcining time is more than 3 hours. 3. The method for preparing nano-titanium dioxide as claimed in claim 1 or 2, characterized in that: the mass percent concentration of concentrated hydrochloric acid is 37%. 4. The method for preparing nano-titanium dioxide according to claim 1 or 2, characterized in that: the drying temperature of the amorphous titanium dioxide powder is lower than 70°C.

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