CN102432064B

CN102432064B - Method for synthesizing nanometer titanium dioxide by reverse microemulsion carbon adsorption titanium tetrachloride hydrolytic system

Info

Publication number: CN102432064B
Application number: CN 201110279338
Authority: CN
Inventors: 郭贵宝; 安胜利; 介瑞华; 魏洪培; 赵永旺
Original assignee: Inner Mongolia University of Science and Technology
Current assignee: Inner Mongolia University of Science and Technology
Priority date: 2011-09-07
Filing date: 2011-09-07
Publication date: 2013-08-28
Anticipated expiration: 2031-09-07
Also published as: CN102432064A

Abstract

The invention relates to a method for synthesizing nanometer titanium dioxide by reverse microemulsion carbon adsorption titanium tetrachloride hydrolytic system, belongs to the field of nano material preparation technology. The invention solves the problems of easy agglomeration and sintering of ultrafine titanium dioxide. The method is comprises the following steps: adopting titanium tetrachloride, carbon black, and acetic acid as raw materials, preparing a cyclohexane microemulsion system by an acetic acid aqueous solution with a pH of 2, dropwisely adding into a cyclohexane microemulsion system formed by titanium tetrachloride, anhydrous alcohol, and carbon black, mixing and stirring at normal temperature, pouring into a reaction kettle, reacting in the microreactor by hydrothermal reaction, reduced-pressure distillation, washing, drying, grinding, and calcining the precipitates adsorbed by the carbon black, obtaining the nanometer titanium dioxide with high-temperature stability. The invention has mild reaction conditions, high yield; the obtained product has high crystallinity, large specific surface area, small particle size, good photocatalytic activity.

Description

The synthetic method of reverse micro emulsion charcoal absorption titanium tetrachloride hydrolysis system nano titanium oxide

Technical field

The present invention relates to the synthetic method of reverse micro emulsion charcoal absorption titanium tetrachloride hydrolysis system nano titanium oxide, belong to the nano material preparation technical field.

Background technology

Photochemical catalysis is a kind of emerging environmental purification technology.Nano titanium dioxide photocatalysis oxidation or reduction effectively is adsorbed on its lip-deep harmful molecule, and kill bacteria suppresses virus, and harmful organic substance, bacterium etc. can be converted into innoxious substances such as water and carbonic acid gas, and without any secondary pollution.The photocatalyst of existing preparation is nano TiO 2 powder mostly, in order to improve the photocatalytic activity of titanium dioxide, must make it have higher degree of crystallinity, smaller particles size and higher specific surface area, in order to there is more chain carrier to participate in reaction, increase active.Present prepared by reverse microemulsion method titanium oxide nanoparticles commonly used, this method be mainly with the water nuclear of the w/o type microemulsion microreactor as precipitin reaction, will contain to remain the microemulsion of precipitating ion and mix with the another kind of microemulsion that contains precipitation agent.The certain concentration gradient of the unavoidable generation of mixing process causes the process of different zones precipitin reaction in the microemulsion asynchronous, and synthetic nano particle diameter distributes and broadens.The titanium dioxide ultra-fine grain that makes all is easy to generate reunion, sintering in dry, roasting stage, and the particle diameter of synthetic nanoparticle increases.Obtaining uniform particles, crystal formation is good, specific surface area is big ultrafine titania and avoid in reunion dry, heat treatment stages as simple preparation method how, is the target that people seek for a long time.

Summary of the invention

The invention provides and a kind ofly can stop reunion and the reverse micro emulsion charcoal of the sintering absorption titanium tetrachloride hydrolysis system nano titanium oxide synthetic method of titanium dioxide in preparation process.

Technical solution:

The present invention includes the method for being prepared as follows:

(1) is to measure titanium tetrachloride and dehydrated alcohol in ice-water bath stir at 0.5～1.5: 20 by volume, gets mixed system A;

(2) the cetyl trimethylammonium bromide CTAB of 0.50～0.7g is dissolved in the 200mL hexanaphthene makes solution B, measure 5mL mixed system A, add in the solution B, stir, be that achromaticity and clarification is stablized microemulsion C to system, be 0.50～0.85: 1 ratio weighing carbon black again in contained titanium tetrachloride mass ratio among carbon black and the microemulsion C, carbon black is added solution C, continue in ice-water bath, to stir, ultrasonic oscillation 1～2h gets mixed system D;

(3) 0.50～0.7g cetyl trimethylammonium bromide CTAB is dissolved in the 200mL hexanaphthene, the pH value that dropping is disposed with acetic acid is 1～2 aqueous acetic acid 2.5ml, drips 6～8ml propyl carbinol simultaneously, stir, and be that achromaticity and clarification is stablized microemulsion E to system;

(4) mixed system D is mixed with microemulsion E, stir 20～40min, pour into then in the teflon-lined autoclave, temperature: 120 ℃～160 ℃, be cooled to room temperature after stirring 8～14h, gained charcoal adsorption precipitation thing deionized water wash, dry 3～5h under 80～100 ℃ condition, heat-up rate with 10～20 ℃/min after grinding is warming up to 500～800 ℃ of roasting 2～4h, gets the high thermal stability nano titanium oxide.

Described acetic acid is Glacial acetic acid.

Transferring to pH value of aqueous solution with Glacial acetic acid is 2.

The present invention adds the another kind of microemulsion that contains precipitation agent then and mixes the Ti of formation (OH) owing to add suitable carbon black in treating the microemulsion of precipitating ion ₄Fine powder is adsorbed by carbon black, has stoped ultra-fine grain to produce at precipitation, drying stage on the one hand and has reunited.On the other hand, when dried mixture is elevated to 300 ℃ when temperature, Ti (OH) ₄The powder decomposition has formed TiO ₂Nano-powder, this moment, carbon was not oxidized, had prevented TiO ₂Nano-powder is at the sintering in roasting stage.TiO ₂Nano-powder is actually the product that microemulsion and adsorbing coupled " wetting " process of carbon combine with " doing " process, be expected to synthesize the particle that has than small particle size and concentrated size distribution, prepare reunion and the sintering problem of Nano titanium dioxide for solution utilizes the microemulsion method.

In a single day effect of the present invention: the present invention adds an amount of carbon black in microemulsion, as strong sorbent material, forms nano particle in microreactor, adsorbed by carbon black, has stoped ultra-fine grain in precipitation, dry, roasting stage generation reunion.Thermal treatment does not see that rutile produces mutually under 800 ℃ of hot conditionss, illustrates to adopt the reverse micro emulsion carbon adsorption can significantly improve the transition temperature of anatase titanium dioxide, thereby improves its thermostability; 500 ℃ of roasting 2h charcoal absorption nano titanium oxide specific surface areas are 78.6m ²/ g, about 18 nanometers of particle diameter, the specific surface area synthetic with the degussa vapor phase process is about 50m ²/ g nano titanium oxide (TiO ₂P25) compare, specific surface area increases about 28m ²/ g.Adopt the carbon adsorption production cost low, be convenient to carry out the production of extensive nano titanium oxide.

Reaction conditions gentleness of the present invention, productive rate height; The product degree of crystallinity height that obtains, specific surface area is big, and particle diameter is little, and photocatalysis performance is good.

Description of drawings

Fig. 1 is the XRD spectra of specific embodiment of the invention gained charcoal absorption titanium dioxide sample behind 800 ℃ of maturing temperature sintering;

Fig. 2 is 500 ℃ of SEM figure behind the sintering for specific embodiment of the invention gained charcoal absorption titanium dioxide sample through maturing temperature.

Embodiment

(1) get titanium tetrachloride 1.85ml and dehydrated alcohol 37ml, magnetic agitation, ultrasonic oscillation in ice-water bath are total to 1h and get mixed solution A with titanium tetrachloride and raw spirit;

(2) cetyl trimethylammonium bromide (CTAB) of 0.60g is dissolved in the 200mL hexanaphthene makes solution B, the mixing solutions 5mL that step (1) is prepared slowly adds in the solution B, stir, transfer achromaticity and clarification to system to by the opaque milk sap of oyster white and stablize microemulsion, the 0.31g carbon black is added in the solution B, and continuation is stirred in ice-water bath, ultrasonic oscillation is total to 2h and gets mixed system C;

(3) 0.60g cetyl trimethylammonium bromide (CTAB) is dissolved in the 200mL hexanaphthene, dropping is 2 aqueous acetic acid 2.5ml with the pH value of acetic acid configuration, drips propyl carbinol 7ml simultaneously and transfers achromaticity and clarification to system to by the opaque milk sap of oyster white and stablize microemulsion D;

(4) mixed system C is mixed with microemulsion D, stir 20～40min, pour into then in the teflon-lined autoclave, at 150 ℃, stir down and be cooled to room temperature behind the hydro-thermal 10h, gained charcoal adsorption precipitation thing is after repeatedly washing, and drying and grinding back are warming up to 500 ℃ or 800 ℃ of roasting 4h with the heat-up rate of 10 ℃/min again, get the high thermal stability nano titanium oxide.

Comparative example: as a comparison, we utilize the synthetic nano titanium oxide (TiO of degussa vapor phase process ₂P25) compare, the nano titanium oxide that the present invention makes, as shown in Figure 1, thermal treatment does not see that rutile produces mutually under 800 ℃ of hot conditionss, illustrate and adopt the reverse micro emulsion carbon adsorption can significantly improve the transition temperature of anatase titanium dioxide, thereby improve its thermostability; 500 ℃ of roasting 2h charcoal absorption nano titanium oxide specific surface areas are 78.6m ²/ g, about 18 nanometers of particle diameter, the specific surface area synthetic with the degussa vapor phase process is about 50m ²/ g nano titanium oxide (TiO ₂P25) compare, specific surface area increases about 28m ²/ g.Simultaneously, as shown in Figure 2, the nano titanium oxide that the present invention makes, the degree of crystallinity height, specific surface area is big, and particle diameter is little, adopts the carbon adsorption production cost low, is convenient to carry out the production of extensive nano titanium oxide.

Claims

1. the reverse micro emulsion charcoal adsorbs the synthetic method of titanium tetrachloride hydrolysis system nano titanium oxide, it is characterized in that method steps is as follows:

(2) the cetyl trimethylammonium bromide CTAB of 0.50～0.7g is dissolved in the 200mL hexanaphthene makes solution B, measure 5mL mixed system A, add in the solution B, stir, stablize microemulsion C for clarification to system, be 0.50～0.85: 1 ratio weighing carbon black again in contained titanium tetrachloride mass ratio among carbon black and the microemulsion C, carbon black is added solution C, continue in ice-water bath, to stir, ultrasonic oscillation 1～2h gets mixed system D;

(3) 0.50～0.7g cetyl trimethylammonium bromide CTAB is dissolved in the 200mL hexanaphthene, the pH value that dropping is disposed with acetic acid is 2 glacial acetic acid aqueous solution 2.5ml, drips 6～8ml propyl carbinol simultaneously, stir, and be that microemulsion E is stablized in clarification to system;