CN102430410A - Preparation method of TiO2/SiO2/NiFe2O4 magnetic composite photocatalyst - Google Patents

Abstract

The invention relates to a preparation method of a TiO2/SiO2/NiFe2O4 magnetic composite photocatalyst. The method is mainly characterized in that a hydrothermal method is utilized to prepare magnetic nickel ferrite particles, a hydrolytic precipitation method is utilized to coat a silicon dioxide layer outside the nickel ferrite particles, and a sol-gel method is utilized to deposit TiO2 on the SiO2/NiFe2O4 surface by using SiO2/NiFe2O4 as a magnetic core and tetrabutyl titanate as a precursor. The invention has the following advantages: the particles of the material are small, and TiO2 and NiFe2O4 are isolated by the silicon dioxide; and thus, the photocatalysis performance of the titanium dioxide is not influenced by the nickel ferrite, and the titanium dioxide can be effectively recycled through an external magnetic field. In addition, the magnetic substance used in the method is nickel ferrite with stable properties, and the magnetic performance of the nickel ferrite can not be influenced by high-temperature calcination.

Description

TiO 2/ SiO 2/ NiFe 2O 4The preparation method of magnetic composite photocatalyst

Technical field

The present invention relates to a kind of TiO ₂/ SiO ₂/ NiFe ₂O ₄The preparation of magnetic composite photocatalyst belongs to the magnetic photocatalyst technical field of material.

Background technology

Photocatalysis is a kind of very potential water technology, and it and traditional water treatment compared with techniques have remarkable advantages, such as: disposal ability is strong, reaction condition is gentle, non-secondary pollution or the like.But in the suspension system recovery issues limit of catalyst its application; Much human is attempted that photochemical catalyst is fixed on a kind of carrier such as bead, glass fibre, zeolite etc. and is gone up preparation fixed composite photo-catalyst; Perhaps photocatalyst film; But this method has reduced the specific area and the mass transfer rate of catalyst, and the active of photochemical catalyst significantly reduced.In recent years, there is the people that photochemical catalyst is combined with magnetic material, utilizes externally-applied magnetic field to separate, obtained good effect.Magnetic photocatalyst not only has very big specific area, and mass transfer rate is high, under the externally-applied magnetic field effect, is easy to separate, and has solved the drawback of fixed titanium dioxide well.

Summary of the invention

The objective of the invention is to prepare the magnetic titanium dioxide composite photo-catalyst that a kind of photocatalysis performance is good, be easy to reclaim.

A kind of TiO of the present invention ₂/ SiO ₂/ NiFe ₂O ₄The preparation method of composite magnetic photochemical catalyst is characterized in that having following preparation process and step:

A. NiFe ₂O ₄Preparation

At first prepare Ni ferrite (NiFe ₂O ₄), nickel nitrate and ferric sesquichloride are dissolved in an amount of distilled water by the 1:2 mol ratio altogether; Add the hydrazine hydrate that concentration is 1mol/L then, wherein the volume ratio of distilled water and hydrazine hydrate is 20:1; The mass volume ratio of nickel nitrate and hydrazine hydrate is 1:2.3, the hydrazine hydrate that the nickel nitrate configuration of promptly per 1 gram mass is 2.3 milliliters; After stirring, add an amount of sodium hydroxide solution, the pH value of above-mentioned mixed liquor is adjusted to 10～11; Change over to then in the autoclave, in 180 ℃ of angry temperature reaction 8h; Reaction finishes the back and takes out autoclave, is washed with distilled water to neutrality, and suction filtration, drying, grinding then obtains magnetic NiFe ₂O ₄Powder.

B. SiO ₂/ NiFe ₂O ₄Preparation

Take by weighing the magnetic NiFe of an amount of above-mentioned preparation gained ₂O ₄Powder joins in an amount of absolute ethyl alcohol, and ultrasonic dispersion adds in the ammonia spirit of distilled water that volume ratio is 5:1 and concentrated ammonia liquor again, stirs; Then to the above-mentioned mixed liquor that dropwise adds ethyl orthosilicate and absolute ethyl alcohol in the liquid that is mixed in; The volume ratio of ethyl orthosilicate and absolute ethyl alcohol is 1:40; The used Ni ferrite powder and the mass volume ratio of ethyl orthosilicate are 1:0.9; It is the ethyl orthosilicate of 0.9 milliliter of per 1 gram Ni ferrite configuration; Constantly stir and reaction 2h; Filtering, dry, grinding, obtain SiO ₂/ NiFe ₂O ₄Powder;

C. TiO ₂/ SiO ₂/ NiFe ₂O ₄The preparation of magnetic composite photocatalyst

The SiO that takes by weighing an amount of above-mentioned preparation and get ₂/ NiFe ₂O ₄Powder is incorporated in an amount of absolute ethyl alcohol, adds a certain amount of butyl titanate again; Described SiO ₂/ NiFe ₂O ₄The mass volume ratio of powder and described butyl titanate consumption is 1: (0.09～0.1); Be per 1 milligram of SiO ₂/ NiFe ₂O ₄The butyl titanate that the powder configuration is 0.09～0.1 milliliter; Mixed liquor is carried out ultrasonic dispersion, make it even; And then to add its pH value be 3 the absolute ethyl alcohol and the fused solution of distilled water, constantly stirs, and makes its reaction, and make mixed liquor change gel into from colloidal sol; Ageing 24h then; And in 80 ℃ of following dry 12h; Take out the back and grind, put into 500 ℃ of Muffle furnaces again and calcine 2.5h; Finally make TiO ₂/ SiO ₂/ NiFe ₂O ₄Powder is magnetic composite photocatalyst.

The characteristics of the inventive method are following:

(1) TiO of the present invention's preparation ₂/ SiO ₂/ NiFe ₂O ₄Magnetic photocatalyst is TiO ₂, SiO ₂And NiFe ₂O ₄Compound, wherein three's content is TiO respectively ₂95%, SiO ₂1%, NiFe ₂O ₄4%.

(2) TiO of the present invention's preparation ₂/ SiO ₂/ NiFe ₂O ₄The coercivity of magnetic photocatalyst is 160.72G, and saturation magnetization is 1.4411emu/g, and remanent magnetism is 0.37011emu/g.

(3) TiO that the present invention is prepared ₂/ SiO ₂/ NiFe ₂O ₄Magnetic photocatalyst 0.16g joins in the methyl orange solution of 80ml 10mg/L, ultrasonic 30min, and 30min is stirred in the dark place; Make it reach the absorption-desorption balance, then at black light lamp (8W, λ=365nm; Totally four lamps) photocatalytic degradation 300min down, the clearance of methyl orange reaches 85.3%.

(4) TiO of the present invention's preparation ₂/ SiO ₂/ NiFe ₂O ₄Magnetic photocatalyst externally-applied magnetic field next time yield can reach more than 90%.

(5) the used magnetic carrier is NiFe among the present invention ₂O ₄, its stable in properties, high-temperature calcination does not influence its magnetic behavior.

(6) NiFe in the sample of the present invention's preparation ₂O ₄Content is few, has not only reduced cost, has also reduced magnetisable material to TiO ₂The adverse effect of photocatalysis performance.

Description of drawings

Fig. 1 is TiO ₂/ SiO ₂/ NiFe ₂O ₄The XRD figure spectrum of magnetic composite photocatalyst.

The specific embodiment

After specific embodiment of the present invention being described at present.

Embodiment

Concrete steps in the present embodiment are following:

(1), preparation NiFe ₂O ₄: accurately take by weighing 3.243g FeCl ₃6H ₂O and 1.745g Ni (NO ₃) ₂6H ₂O is dissolved in the 80ml distilled water, adds the hydrazine hydrate solution of 4ml 1mol/L, stirs.Be adjusted to about 10 with the sodium hydroxide solution of 5mol/L pH value then, form suspension mixed liquor.Suspension is transferred in the 150ml autoclave, tightened lid, place 180 ℃ air dry oven hydro-thermal reaction 8h.After reaction finishes, take out autoclave, cooling is transferred to product in the 500ml beaker then rapidly, is washed with distilled water to neutrality, and suction filtration then with product dry 3h in 80 ℃ air dry oven, grinds, and has promptly obtained magnetic NiFe ₂O ₄Powder.

(2), preparation SiO ₂/ NiFe ₂O ₄: accurately take by weighing 0.56g Ni ferrite powder and add in the 20ml absolute ethyl alcohol, ultrasonic dispersion adds 20ml distilled water and 4ml concentrated ammonia liquor again; Mix, in above-mentioned mixed liquor, dropwise add the mixed liquor of 0.5ml ethyl orthosilicate and 20ml absolute ethyl alcohol then, stirring reaction 2h; Filter then; 80 ℃ of oven dry are ground, and promptly obtain SiO ₂/ NiFe ₂O ₄Powder.

(3), preparation TiO ₂/ SiO ₂/ NiFe ₂O ₄: accurately take by weighing 0.032g silica/Ni ferrite powder and add in the 20ml absolute ethyl alcohol, add the 3ml butyl titanate again, ultrasonic being uniformly dispersed is designated as A liquid; In the 10ml absolute ethyl alcohol, add 0.48ml distilled water, and its pH value is adjusted to 3, be designated as B liquid; When stirring, B liquid is dropwise joined in the A liquid, continue stirring reaction to mixed liquor and change gel into from colloidal sol, ageing 24h; Change dry 12h in 80 ℃ of air dry ovens over to, take out, dried product is ground; Put into 500 ℃ of Muffle furnaces again and calcine 2.5h, finally make TiO ₂/ SiO ₂/ NiFe ₂O ₄Powder also is a magnetic composite photocatalyst.

Instrument detecting

The TiO that present embodiment is made ₂/ SiO ₂/ NiFe ₂O ₄Magnetic composite photocatalyst carries out the XRD Instrumental Analysis, and the result is shown among Fig. 1.

Fig. 1 is TiO ₂/ SiO ₂/ NiFe ₂O ₄The XRD figure of magnetic composite photocatalyst is composed, and from figure, can obviously observe the base peak of anatase phase titanium dioxide, and the peak of Ni ferrite is not obvious, because its content is low, is coated fully.

Claims (1)

1. TiO ₂/ SiO ₂/ NiFe ₂O ₄The preparation method of composite magnetic photochemical catalyst is characterized in that having following preparation process and step:

A. NiFe ₂O ₄Preparation

At first prepare Ni ferrite (NiFe ₂O ₄), nickel nitrate and ferric sesquichloride are dissolved in an amount of distilled water by the 1:2 mol ratio altogether; Add the hydrazine hydrate that concentration is 1mol/L then, wherein the volume ratio of distilled water and hydrazine hydrate is 20:1; The mass volume ratio of nickel nitrate and hydrazine hydrate is 1:2.3, the hydrazine hydrate that the nickel nitrate configuration of promptly per 1 gram mass is 2.3 milliliters; After stirring, add an amount of sodium hydroxide solution, the pH value of above-mentioned mixed liquor is adjusted to 10～11; Change over to then in the autoclave, in 180 ℃ of angry temperature reaction 8h; Reaction finishes the back and takes out autoclave, is washed with distilled water to neutrality, and suction filtration, drying, grinding then obtains magnetic NiFe ₂O ₄Powder;

B. SiO ₂/ NiFe ₂O ₄Preparation

Take by weighing the magnetic NiFe of an amount of above-mentioned preparation gained ₂O ₄Powder joins in an amount of absolute ethyl alcohol, and ultrasonic dispersion adds in the ammonia spirit of distilled water that volume ratio is 5:1 and concentrated ammonia liquor again, stirs; Then to the above-mentioned mixed liquor that dropwise adds ethyl orthosilicate and absolute ethyl alcohol in the liquid that is mixed in; The volume ratio of ethyl orthosilicate and absolute ethyl alcohol is 1:40; The used Ni ferrite powder and the mass volume ratio of ethyl orthosilicate are 1:0.9; It is the ethyl orthosilicate of 0.9 milliliter of per 1 gram Ni ferrite configuration; Constantly stir and reaction 2h; Filtering, dry, grinding, obtain SiO ₂/ NiFe ₂O ₄Powder;

C. TiO ₂/ SiO ₂/ NiFe ₂O ₄The preparation of magnetic composite photocatalyst

The SiO that takes by weighing an amount of above-mentioned preparation and get ₂/ NiFe ₂O ₄Powder is incorporated in an amount of absolute ethyl alcohol, adds a certain amount of butyl titanate again; Described SiO ₂/ NiFe ₂O ₄The mass volume ratio of powder and described butyl titanate consumption is 1: (0.09～0.1); Be per 1 milligram of SiO ₂/ NiFe ₂O ₄The butyl titanate that the powder configuration is 0.09～0.1 milliliter; Mixed liquor is carried out ultrasonic dispersion, make it even; And then to add its pH value be 3 the absolute ethyl alcohol and the fused solution of distilled water, constantly stirs, and makes its reaction, and make mixed liquor change gel into from colloidal sol; Ageing 24h then; And in 80 ℃ of following dry 12h; Take out the back and grind, put into 500 ℃ of Muffle furnaces again and calcine 2.5h; Finally make TiO ₂/ SiO ₂/ NiFe ₂O ₄Powder is magnetic composite photocatalyst.

Images