CN103041795A

CN103041795A - Preparation method of titanium dioxide photocatalyst

Info

Publication number: CN103041795A
Application number: CN2012105808773A
Authority: CN
Inventors: 冯庆革; 张菲; 宋宝玲; 李浩璇; 刘少友; 王孝英; 王婷; 王东波; 覃思颖
Original assignee: Guangxi University; Kaili University
Current assignee: Guangxi University; Kaili University
Priority date: 2012-12-27
Filing date: 2012-12-27
Publication date: 2013-04-17

Abstract

A preparation method of a titanium dioxide photocatalyst comprises the following steps of: by a solid phase method, selecting titanyl sulfate dehydrate as a titanium source, and performing solid phase reaction on the titanyl sulfate dehydrate with sodium oxalate at room temperature by a mechanical polishing method under the condition that a small amount of surfactant is added so as to obtain a precursor titanyl oxalate; and calcining the precursor at a certain temperature, eluting and purifying to obtain the titanium dioxide photocatalyst. The titanium dioxide photocatalyst can degrade methyl orange into carbon dioxide, water and a small amount of small molecular organic substance under the conditions of room temperature and ultraviolet irradiation, and has the significant advantage as follows: the methyl orange can be degraded to a relatively great degree within a relatively short irradiation time. Therefore, the solid-phase preparation method of the titanium dioxide is a feasible method which is easy to operate and energy-saving.

Description

A kind of preparation method of titanium dioxide optical catalyst

One, technical field

The invention belongs to environmental catalysis material technology field, be specifically related to a kind of preparation method of titanium dioxide optical catalyst, and the application of this catalyst in photo-catalytic degradation of methyl-orange.

Two, background technology

The advantages such as titanium dioxide is high, cheap and easy to get with its stability, good, the antiacid caustic corrosion ability of chemical stability is strong, nontoxic, it is a kind of good photochemical catalyst, be used to persistent organic pollutants in the sewage always, removal such as azo dyes, rhodamine, phenol, nitrobenzene etc., in photocatalysis research, be in core status, and worldwide be widely used.

At present, the main method of preparation titanium dioxide optical catalyst has liquid phase method and vapor phase method, liquid phase method such as sol-gel process, alkoxide hydrolysis etc., agglomeration is grown, is prone to reaction time, and colloidal sol is subject to the impact of the factors such as addition, inhibitor, acid and the solvent species of pure titanium salt kind, water and complexing additive usually, has brought inconvenience for the industrialized production of titanium dioxide to a certain extent; Vapor phase method such as gas phase oxyhydrogen flame Hydrolyze method require very high to the pattern of the material of equipment and reactor, and exist production cost high, the deficiencies such as process technologies complexity.Therefore seek new, easy and simple to handle and be easy to realize that the synthetic method of the preparation titanium dioxide optical catalyst of industrialized production has become the major issue that needs to be resolved hurrily.In recent years, solid reaction process is low with its cost, productive rate is high, technique is simple, need not solvent, be fit to the attention that the advantage such as large-scale production is subject to numerous scholars day by day, and as a kind of new chemical synthesis means, its superiority day by day reveals.Sum up forefathers' achievement in research, discovery still remains in depth to be explored about the correlative study of adopting solid phase method to prepare the titanium dioxide optical catalyst aspect and is perfect, sintering temperature is left to be desired on the scheduling theory that affects of titanium dioxide optical catalyst crystal formation on the one hand, it is to be determined to be that optimum calcination temperature has, and the photocatalytic activity of product has to be evaluated on the other hand.

Three, summary of the invention

The object of the present invention is to provide a kind of preparation method of titanium dioxide optical catalyst, it can by simple operation process, obtain to have the catalysis material of high light catalytic performance.

The present invention achieves the above object by the following technical programs: a kind of preparation method of titanium dioxide optical catalyst, and with TiOSO ₄2H ₂O is the titanium source, adopts the method for mechanical lapping to make itself and Na ₂C ₂O ₄Solid phase reaction occurs at normal temperatures, and through roasting, washing purifying, oven dry obtains TiO again ₂Photochemical catalyst, concrete preparation process is:

(1) 1.0 ~ 1.2:1 takes by weighing respectively Na in molar ratio ₂C ₂O ₄And TiOSO ₄2H ₂O;

(2) with Na ₂C ₂O ₄Place agate mortar to grind 15 ~ 30min, stand-by;

(3) with TiOSO ₄2H ₂After O and surfactant mix, grind 15 ~ 30min, obtain mixture A;

(4) Na after will grinding ₂C ₂O ₄And the mixture A of step (3) gained changes in another agate mortar, and then mixed grinding 50 ~ 90min is placed in the thermostatic drying chamber, in 60～105 ℃ of lower 6 ~ 24h that keep, and naturally cooling after taking out, grinding namely obtains presoma TiOC ₂O ₄

(5) with presoma TiOC ₂O ₄Place Muffle furnace in 300 ~ 800 ℃ of lower roasting 4 ~ 7h, removed at this Surface During activating agent, simultaneously TiOC ₂O ₄Decompose; The decomposition reaction equation:

(6) after step (5) products therefrom naturally cools to room temperature, porphyrize is again through repeatedly washing, until with the BaCl of 1g/L ₂Solution qualitative reaction supernatant free from admixture ion exists, and oven dry obtains TiO ₂Photochemical catalyst.

Described surfactant is polyethylene glycol PEG, is specially PEG-200, PEG-400 or PEG-600, and described surfactant is all the water soluble polymer organic compound, belongs to nonionic surface active agent, and its consumption is pressed Na ₂C ₂O ₄And TiOSO ₄2H ₂1.0 ~ 2.5% of O gross weight adds.Add surfactant and play lubricated, as to increase the contact between the reaction mass effect that disperses.

Described washing operation comprises deionized water washing and absolute ethanol washing.

Outstanding advantages of the present invention is:

Compare with sol-gel process with traditional vapor phase method, not only employed equipment is simple in the present invention, operating process convenient, preparation condition is gentle, and can be under the prerequisite of utilizing comparatively cheap raw material, namely obtain the higher titanium dioxide optical catalyst of photocatalytic activity by simple grinding, calcining, washing etc., avoid adopting the some shortcomings that exist in liquid phase method and the vapor phase method and the restriction of many correlative factors; Simultaneously, provide more fully theoretical foundation for adopting solid phase method to produce titanium dioxide optical catalyst, for its suitability for industrialized production has indicated direction.

Four, description of drawings

Fig. 1 is under 300 ~ 800 ℃ of different sintering temperatures with Fig. 2, the TiO that obtains ₂The XRD collection of illustrative plates of sample.

Five, the specific embodiment

Below by embodiment technical scheme of the present invention is described further.

Embodiment 1

Accurately take by weighing 19.5960g TiOSO ₄2H ₂O and 0.3300g PEG-200 place agate mortar mixed grinding 15min, add the 13.4000g Na that grinds gained through 15min again ₂C ₂O ₄Mix, grind again 50min, the gained mixture is placed thermostatic drying chamber, in 60 ℃ of lower 6h that keep, naturally cool to room temperature after the taking-up, obtain presoma TiOC ₂O ₄Get presoma TiOC ₂O ₄Totally three parts, change over to respectively in three porcelain crucibles, place Muffle furnace, respectively at 300 ℃, 350 ℃, 400 ℃ lower roasting 4h, obtain containing the TiO of impurity ₂, described impurity mainly is Na ₂SO ₄, after temperature is down to 100 ℃ times, takes out and put into drier and naturally cool to room temperature, after the grinding, adopt the mode of centrifuge washing, use successively deionized water and absolute ethyl alcohol cyclic washing, to containing the TiO of impurity ₂Powder carries out purifying, until with the BaCl of 1g/L ₂Solution qualitative reaction supernatant to free from admixture ion exists, washing finish to be placed in the thermostatic drying chamber in 85 ℃ lower dry, until oven dry, take out place in the drier naturally cooling after, grinding obtains TiO again ₂Photocatalyst product.

TiO in the product that 300 ℃, 350 ℃, the 400 ℃ lower roastings of embodiment 1 are made ₂The analysis result of the XRD diffracting spectrum of sample as can be known, the heat treatment process, the diffraction peak intensity of sample is grow along with the rising of calcining heat from 300 ℃ to 400 ℃, half-peak breadth then narrows down gradually, shows that crystal grain grows up gradually with the rising of sintering temperature.

Embodiment 2

Accurately take by weighing 19.5960g TiOSO ₄2H ₂O and 0.5050g PEG-400 place agate mortar mixed grinding 20min, add the 14.0700g Na that grinds gained through 20min again ₂C ₂O ₄, mix, grind again 1h, the gained mixture is placed thermostatic drying chamber, in 85 ℃ of lower 24h that keep, naturally cool to room temperature after the taking-up, obtain presoma TiOC ₂O ₄, with presoma TiOC ₂O ₄Change in the porcelain crucible, place Muffle furnace, in 450 ℃ of lower roasting 4h, obtain containing the TiO of impurity ₂Equally, operate according to method and the step of the removal of impurities described in the embodiment 1, finally obtain TiO ₂Photocatalyst product.

Embodiment 3

Accurately take by weighing 19.5960g TiOSO ₄2H ₂O and 0.8919g PEG-600 place agate mortar mixed grinding 30min, add the 16.0800g Na that grinds gained through 30min again ₂C ₂O ₄Mix, grind again 1.5h, the gained mixture is placed thermostatic drying chamber, in 105 ℃ of lower 12h that keep, naturally cool to room temperature after the taking-up, obtain presoma TiOC ₂O ₄Get presoma TiOC ₂O ₄Totally two parts, change over to respectively in two porcelain crucibles, place Muffle furnace, respectively at 650 ℃, 800 ℃ lower roasting 7h, obtain containing the TiO of impurity ₂Equally, operate according to method and the step of the removal of impurities described in the embodiment 1, finally obtain TiO ₂Photocatalyst product.

To embodiment 2 and embodiment 3 products therefrom TiO ₂The interpretation of result of the XRD diffracting spectrum of sample as can be known, the present invention is with TiOSO ₄2H ₂O is the titanium source, the TiO in the product that the employing solid reaction process makes ₂Be Anatase, not only crystal property is good in 450 ℃ of prepared products of lower roasting, and purity is high, and the average grain size that adopts the Scherrer equation to calculate this product is about 10.2nm.When temperature was higher than 650 ℃, titanate began to form, and is mainly Na ₂Ti ₃O ₇Until after 800 ℃ of roastings, TiO ₂Remain with Anatase and exist, this is because a large amount of Na ⁺Existence, improved TiO ₂Brilliant temperature and heat endurance, namely its brilliant temperature has been produced hysteresis.

Embodiment 4

Adopt many test tube types photochemical reaction instrument, estimate TiO take methyl orange as the target degradation product ₂The photocatalytic activity of photochemical catalyst, concrete steps are as follows: 450 ℃ of prepared TiO of lower roasting that accurately take by weighing 0.1000g ₂Photochemical catalyst is in quartz ampoule, and pipetting initial concentration is 20mg/L, and pH is that 3 methyl orange solution 50mL is in quartz ampoule, open magnetic agitation, set mixing speed 750r/min, carry out first the dark reaction of 30min, so that catalyst and methyl orange molecule reach adsorption equilibrium; Open mercury lamp again and enter photoreaction stage, detect every the 3min sampling, adopt " single tube sampling method " every sub-sampling 5mL, then suspension is carried out centrifugation, centrifugation time is 5min, and centrifugal speed is 8000r/min; Centrifugal complete after, get supernatant and measure it at the absorbance (A at characteristic absorption wavelength place _t), use with respect to the initial absorbance (A of methyl orange ₀) changing value react its degradation rate.After the detection, the catalyst that detects in liquid and the centrifuge tube is refunded continuation reaction in the corresponding former quartz ampoule in the lump.Ultraviolet-ray visible absorbing collection of illustrative plates in conjunction with methyl orange solution in the Photocatalytic Degradation Process draws, and under this study condition, methyl orange solution is after the UV illumination of 15min, and solution becomes colorless, and percent of decolourization has reached 99.3%.With TiO ₂The similar research of photo-catalytic degradation of methyl-orange is compared, and among the present invention, adopts the prepared TiO of solid phase method ₂Photocatalytic activity is good, in the short period of time, can make methyl orange obtain maximum decolorization and degradation.

Claims

1. the preparation method of a titanium dioxide optical catalyst is characterized in that, with TiOSO ₄2H ₂O is the titanium source, adopts the method for mechanical lapping to make itself and Na ₂C ₂O ₄Solid phase reaction occurs at normal temperatures, and through roasting, washing purifying, oven dry obtains TiO again ₂Photochemical catalyst, concrete preparation process is:

(2) with Na ₂C ₂O ₄Place agate mortar to grind 15 ~ 30min, stand-by;

2. the preparation method of titanium dioxide optical catalyst according to claim 1, it is characterized in that, described surfactant is polyethylene glycol PEG, be specially PEG-200, PEG-400 or PEG-600, described surfactant is all the water soluble polymer organic compound, belong to nonionic surface active agent, its consumption is pressed Na ₂C ₂O ₄And TiOSO ₄2H ₂1.0 ~ 2.5% of O gross weight adds.