CN104801308A - NiFe2O4/TiO2/sepiolite composite photocatalyst and preparation method thereof - Google Patents

Abstract

The invention discloses a NiFe2O4/TiO2/sepiolite composite photocatalyst which comprises the components of sepiolite, TiO2 and NiFe2O4, wherein the sepiolite is taken as a carrier, the TiO2 coats the surface of the sepiolite in a form of film, and the NiFe2O4 is loaded on the surface of the TiO2 in a form of granule. The invention also provides a preparation method of the NiFe2O4/TiO2/sepiolite composite photocatalyst. According to the NiFe2O4/TiO2/sepiolite composite photocatalyst and the preparation method thereof disclosed by the invention, the TiO2 coats the surface of the sepiolite in the form of film, and the NiFe2O4 is loaded on the surface of the TiO2 in the form of granule; the NiFe2O4 is loaded on the surface of the TiO2 film in the form of granule, does not shield the whole TiO2 film but forms a coincidence effect with the TiO2; the sepiolite is taken as the carrier, so that the adsorption capacity of the catalyst can be further improved, and further the catalyst simultaneously has the advantages of good adsorption effect, high photocatalytic activity and capabilities of recovering and repeatedly utilizing, and widens the response range of light; the catalytic activity of the catalyst in an ultraviolet light zone is improved, and the response wavelength of the catalyst is transferred from the ultraviolet light zone to a visible light zone, so that the utilization rate of sunlight can be improved.

Description

A kind of NiFe 2o 4/ TiO 2/ sepiolite composite photo-catalyst and preparation method thereof

Technical field

The present invention relates to photocatalytic oxidation technical field, relate in particular to a kind of NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst and preparation method thereof.

Background technology

Photochemical catalytic oxidation law technology is a kind of new and effective technology for treating industrial waste water being applied to field of wastewater over nearly twenties years.Photochemical catalyst conventional in photochemical catalytic oxidation law technology is nano-TiO ₂, it is for wastewater treatment, is a new breakthrough of green technology.Nano-TiO ₂photochemical catalyst is under the irradiation of ultraviolet light, the electron-hole pair that energy generation is oxidized and reducing power is stronger, the chloro phenols, halogenated hydrocarbon, dioxin, various organic acids etc. that can effectively degrade in paper waste, and except cleanliness is high, degradation speed is fast, non-secondary pollution, life cycle pollutant that is long, that be suitable for is wide, reach the object of once-used degradeable pollutant, so very extensive to its research.

At present, TiO ₂to come with some shortcomings in actual application part as photochemical catalyst, such as: TiO ₂photochemical catalyst quantum efficiency low, Selective adsorption is poor, and condition of cure is harsh, easily cohesion, easy in inactivation, and spectral response range is at ultraviolet region, and in solar spectrum, visible light part can not effectively utilize, and these all limit TiO ₂commercial Application.For TiO ₂as the deficiency that photochemical catalyst exists, domestic and international to TiO at present ₂photochemical catalyst mainly carries out the study on the modification of two aspects: one is exploitation TiO ₂loaded photocatalyst; Two is to TiO by doping ₂carry out modification, make it be utilized better in actual applications.

At TiO ₂in loaded photocatalyst research field, researcher is had to develop TiO ₂/ sepiolite supported type photochemical catalyst, this catalyst is at sepiolite surface parcel TiO ₂, sepiolite is moisture zeopan clay mineral, low price, and wide material sources are a kind of porous media materials with more bigger serface, can improve the adsorption effect to organic pollution.There is a large amount of microchannel in sepiolite crystal structure, be combined by countless parallel tubular shape duct, its specific area is large, and sepiolite adsorption property is subject to the restriction of its crystal structure.Sepiolite surface charge is broken by the Si-O key on its surface and Al-O key generation hydrolysis, acid can be become, also can as alkali, the hydroxyl (-OH) on the R-OH that broken key hydrolysis produces, therefore it has both sexes, these surface reactions make sepiolite surface band electric charge.Modifying function mainly makes sepiolite structure charge in aqueous and surface charge change, thus changes charging property and the adsorption activity of sepiolite.

Passing through doping to TiO ₂carry out modification field, have researcher to utilize magnetic material to TiO ₂carry out the composite catalyst adulterating to be formed, conventional doping gimmick has at Fe ₃o ₄or CoFe ₂o ₄surface parcel TiO ₂, this composite catalyst can increase light abstraction width, photocatalytic activity.In addition owing to being doped with magnetic material, be conducive to the recovery and reuse of catalyst.

Summary of the invention

Technical problem to be solved by this invention is to provide and a kind ofly has the NiFe of advantage that advantages of good adsorption effect, photocatalytic activity are high, can reclaim and reuse simultaneously ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.

In order to solve the problems of the technologies described above, the present invention adopts following technical scheme: a kind of NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, composition comprises sepiolite, TiO ₂and NiFe ₂o ₄, sepiolite is carrier, TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface.

Further, wherein the content of Ni is 1-2wt%, the content of Fe is 1.9-3.8wt%, the content of Ti is 12-18wt%, more than be divided into sepiolite.NiFe ₂o ₄/ TiO ₂when each constituent content of/sepiolite composite photo-catalyst is within the scope of this, its good catalytic activity.

Further, the content of the content of Ni to be the content of 1.5wt%, Fe be 2.8wt%, Ti is 15wt%, more than be divided into sepiolite.

The present invention also provides described NiFe ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst, comprises the following steps:

(1) pretreatment of sepiolite

Sepiolite powder is broken into end, be placed in dust technology immersion 15-24h that concentration is 5-15%, filter, with water rinse to neutral post-drying, then at the temperature lower calcination 2-4h of 400-500 DEG C, filtered out by the sepiolite floating on water body upper position with water rinse, after dry, sieve gets particle diameter is that 100-125 object sepiolite powder are as carrier;

(2) TiO ₂the preparation of colloidal sol

Under room temperature, by volume part, the butyl titanate of 15-20 is fully dissolved in the absolute ethyl alcohol of 40-50, then the acetylacetone,2,4-pentanedione of 5-6 is added, obtain solution A, solution B is obtained after the distilled water of 0.75-1.0 and the absolute ethyl alcohol of 20-25 fully being mixed, under the condition constantly stirred, solution B is joined in solution A gradually, then with red fuming nitric acid (RFNA) or concentrated hydrochloric acid, pH value is adjusted to 4-5, stir l-2h, add the polyethylene glycol of 1-1.5, then under the condition of 40-65 DEG C, stir l-1.5h, obtain the TiO of yellow transparent ₂colloidal sol, by TiO ₂colloidal sol is ageing 12-15h at room temperature;

(3) at sepiolite surface parcel TiO ₂film

TiO ₂the number of plies of film is 1-3 layers, every layer of TiO ₂the formation method of film is: under room temperature, sepiolite is joined TiO ₂in colloidal sol, be stirred to and TiO ₂colloidal sol mixes completely, then dries under the condition of 70-85 DEG C, finally under the condition of 400-500 DEG C, calcines 1-3h, for subsequent use after cooling;

(4) at TiO ₂film area load NiFe ₂o ₄particle

Under room temperature, by weight, by the Ni (NO of 2.91-5.82 ₃) ₂6H ₂fe (the NO of O and 8.08-16.16 ₃) ₃9H ₂o joins in the absolute ethyl alcohol of 55.3-63.2, stirs 30-60min, by the NaOH solution of 5-20mol/L, pH value is adjusted to 9-10, then adds and be enclosed with TiO ₂the sepiolite of film, stirs 30-60min, then under the condition of 160-180 DEG C, reacts 18-24h, carries out Separation of Solid and Liquid, washing, finally dry under the condition of 70-85 DEG C, obtain described NiFe after cooling ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.

For the purpose of succinctly describing, NiFe of the present invention below ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst referred to as this catalyst, described NiFe ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst is referred to as this method.

Beneficial effect of the present invention is:

(1) this catalyst is by TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface, NiFe ₂o ₄load is at TiO in the form of granules ₂film surface, can not cover whole TiO ₂film, but and TiO ₂form a coincidence effect, using sepiolite as carrier, can further improve the adsorption capacity of catalyst, thus this catalyst is had simultaneously advantages of good adsorption effect, photocatalytic activity are high, can reclaim and reuse advantage, and expanded photoresponse scope, this catalyst is not only improved in the catalytic activity of ultraviolet region, and response wave length moves to visible region from ultraviolet region, thus can improve the utilization rate of sunshine.

(2) this catalyst have employed NiFe ₂o ₄, NiFe ₂o ₄not only there is magnetic action, be easy to reclaim and recycling, and NiFe ₂o ₄under ultraviolet light also can catalyzing and degrading pollutant as catalyst, its load is at TiO ₂film surface, improves the degradation rate of this catalyst at ultraviolet region on the one hand, widens photoresponse scope to visible region on the other hand.

(3) this method is by NiFe with hydro-thermal method ₂o ₄synthesis load is at TiO ₂film surface, the feature of hydro-thermal method to prepare that purity is higher, the nano particle of good dispersion, good crystalline, so just makes NiFe ₂o ₄with the form of nano particle very equably load at TiO ₂film surface, and be that forced hydrolysis generates Ni (OH) due to what adopted before hydro-thermal reaction ₂with Fe (OH) ₃, do not add hydrolysis inhibitor and surfactant, thus ensure NiFe in hydro-thermal reaction subsequently ₂o ₄not easily exist in membrane form, but be distributed in TiO with graininess ₂film surface.

(4) this method is calcined sepiolite in the preprocessing process of sepiolite, impurity in sepiolite surface and internal void can be become gaseous material to remove, thus increase sepiolite specific surface area and porosity, improve surface area and the adsorption capacity of sepiolite, be conducive to TiO ₂load, improve photocatalysis performance.

(5) this method is at TiO ₂in the preparation process of colloidal sol, butyl titanate and distilled water generation hydrolysis generate TiO ₂colloidal sol, because the hydrolysis of butyl titanate is very violent, so add the inhibitor of acetylacetone,2,4-pentanedione as it, acetylacetone,2,4-pentanedione and butyl titanate form ligand, and a large amount of water can not be removed, and these ligands prevent hydrolysis to carry out, and TiO ₂further polymerization, thus form stable colloidal solution.

(6) this method is at sepiolite surface parcel TiO ₂1-3 layers of TiO have been wrapped up in the process of film ₂film, along with TiO ₂the increase of rete number, catalytic effect can be become better and better, and works as TiO ₂when rete number is more than 3 layers, catalytic effect is deteriorated.

Accompanying drawing explanation

Fig. 1 is the NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the scanning electron microscope (SEM) photograph of/sepiolite composite photo-catalyst.

Fig. 2 is existing TiO ₂the NiFe of/sepiolite supported type photochemical catalyst and the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the solid ultraviolet-visible light spectrogram of/sepiolite composite photo-catalyst.

Fig. 3 is the NiFe of sepiolite and the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the infrared spectrogram of/sepiolite composite photo-catalyst.

Fig. 4 is with the NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the degradation efficiency figure of/sepiolite composite photo-catalyst photocatalytic degradation methylene blue solution.

Detailed description of the invention

Below in conjunction with embodiment, the invention will be further described:

Embodiment 1

A kind of NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, composition comprises sepiolite, TiO ₂and NiFe ₂o ₄, sepiolite is carrier, TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface, wherein the content of the content of Ni to be the content of 1.5wt%, Fe be 2.8wt%, Ti is 15wt%, more than be divided into sepiolite.

Above-mentioned NiFe ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst, comprises the following steps:

(1) pretreatment of sepiolite

Sepiolite powder is broken into end, be placed in concentration be 5% dust technology soak 20h, filter, with water rinse to neutral post-drying, then Muffle furnace is placed at the temperature lower calcination 4h of 400 DEG C, filtered out by the sepiolite floating on water body upper position with water rinse, after dry, sieve gets particle diameter is that 100 object sepiolite powder are as carrier;

(2) TiO ₂the preparation of colloidal sol

Under room temperature, by volume part, the butyl titanate of 18 is fully dissolved in the absolute ethyl alcohol of 40, then the acetylacetone,2,4-pentanedione of 5.5 is added, obtain solution A, solution B is obtained after the distilled water of 0.88 and the absolute ethyl alcohol of 25 fully being mixed, under the condition constantly stirred, solution B is joined in solution A gradually, then with red fuming nitric acid (RFNA), pH value is adjusted to 4, stir (80r/min) 1.5h, add the polyethylene glycol of 1.2, then under the condition of 52 DEG C, stir (100r/min) lh, obtain the TiO of yellow transparent ₂colloidal sol, by TiO ₂colloidal sol is ageing 12h at room temperature;

(3) at sepiolite surface parcel TiO ₂film

TiO ₂the number of plies of film is 2 layers, every layer of TiO ₂the formation method of film is: under room temperature, sepiolite is joined TiO ₂in colloidal sol, stir (80r/min) 1.2h and make sepiolite and TiO ₂colloidal sol mixes completely, then dries under the condition of 70 DEG C, and drying course adopts first water-bath to steam near dry, then dries with drying box, is finally placed in Muffle furnace under the condition of 500 DEG C to calcine 1h, for subsequent use after cooling;

(4) at TiO ₂film area load NiFe ₂o ₄particle

Under room temperature, by weight, by the Ni (NO of 4.37 ₃) ₂6H ₂fe (the NO of O and 12.12 ₃) ₃9H ₂o joins in the absolute ethyl alcohol of 59, and magnetic agitation (120r/min) 45min, is adjusted to 9 by the NaOH solution of 5mol/L by pH value, then adds and is enclosed with TiO ₂the sepiolite of film, stirs (100r/min) 30min, then under the condition of 180 DEG C, reacts 21h, carry out Separation of Solid and Liquid, washing after cooling, finally dry under the condition of 70 DEG C, obtain described NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.

Embodiment 2

A kind of NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, composition comprises sepiolite, TiO ₂and NiFe ₂o ₄, sepiolite is carrier, TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface, wherein the content of the content of Ni to be the content of 1wt%, Fe be 1.9wt%, Ti is 12wt%, more than be divided into sepiolite.

Above-mentioned NiFe ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst, comprises the following steps:

(1) pretreatment of sepiolite

Sepiolite powder is broken into end, be placed in concentration be 10% dust technology soak 15h, filter, with water rinse to neutral post-drying, then Muffle furnace is placed at the temperature lower calcination 3h of 450 DEG C, filtered out by the sepiolite floating on water body upper position with water rinse, after dry, sieve gets particle diameter is that 112 object sepiolite powder are as carrier;

(2) TiO ₂the preparation of colloidal sol

Under room temperature, by volume part, the butyl titanate of 15 is fully dissolved in the absolute ethyl alcohol of 45, then the acetylacetone,2,4-pentanedione of 5 is added, obtain solution A, solution B is obtained after the distilled water of 0.75 and the absolute ethyl alcohol of 20 fully being mixed, under the condition constantly stirred, solution B is joined in solution A gradually, then with red fuming nitric acid (RFNA), pH value is adjusted to 5, stir (120r/min) lh, add the polyethylene glycol of 1.5, then under the condition of 65 DEG C, stir (80r/min) l.2h, obtain the TiO of yellow transparent ₂colloidal sol, by TiO ₂colloidal sol is ageing 15h at room temperature;

(3) at sepiolite surface parcel TiO ₂film

TiO ₂the number of plies of film is 1 layer, every layer of TiO ₂the formation method of film is: under room temperature, sepiolite is joined TiO ₂in colloidal sol, stir (100r/min) 1.5h and make sepiolite and TiO ₂colloidal sol mixes completely, then dries under the condition of 80 DEG C, and drying course adopts first water-bath to steam near dry, then dries with drying box, is finally placed in Muffle furnace under the condition of 450 DEG C to calcine 2h, for subsequent use after cooling;

(4) at TiO ₂film area load NiFe ₂o ₄particle

Under room temperature, by weight, by the Ni (NO of 2.91 ₃) ₂6H ₂fe (the NO of O and 8.08 ₃) ₃9H ₂o joins in the absolute ethyl alcohol of 55.3, and magnetic agitation (80r/min) 30min, is adjusted to 10 by the NaOH solution of 15mol/L by pH value, then adds and is enclosed with TiO ₂the sepiolite of film, stirs (120r/min) 60min, then under the condition of 160 DEG C, reacts 24h, carry out Separation of Solid and Liquid, washing after cooling, finally dry under the condition of 85 DEG C, obtain described NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.

Embodiment 3

A kind of NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, composition comprises sepiolite, TiO ₂and NiFe ₂o ₄, sepiolite is carrier, TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface, wherein the content of the content of Ni to be the content of 2wt%, Fe be 3.8wt%, Ti is 18wt%, more than be divided into sepiolite.

Above-mentioned NiFe ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst, comprises the following steps:

(1) pretreatment of sepiolite

Sepiolite powder is broken into end, be placed in concentration be 15% dust technology soak 24h, filter, with water rinse to neutral post-drying, then Muffle furnace is placed at the temperature lower calcination 2h of 500 DEG C, filtered out by the sepiolite floating on water body upper position with water rinse, after dry, sieve gets particle diameter is that 125 object sepiolite powder are as carrier;

(2) TiO ₂the preparation of colloidal sol

Under room temperature, by volume part, the butyl titanate of 20 is fully dissolved in the absolute ethyl alcohol of 50, then the acetylacetone,2,4-pentanedione of 6 is added, obtain solution A, solution B is obtained after the distilled water of 1.0 and the absolute ethyl alcohol of 23 fully being mixed, under the condition constantly stirred, solution B is joined in solution A gradually, then with concentrated hydrochloric acid, pH value is adjusted to 4.5, stir (100r/min) 2h, add the polyethylene glycol of 1, then under the condition of 40 DEG C, stir (120r/min) 1.5h, obtain the TiO of yellow transparent ₂colloidal sol, by TiO ₂colloidal sol is ageing 13h at room temperature;

(3) at sepiolite surface parcel TiO ₂film

TiO ₂the number of plies of film is 3 layers, every layer of TiO ₂the formation method of film is: under room temperature, sepiolite is joined TiO ₂in colloidal sol, stir (120r/min) 1h and make sepiolite and TiO ₂colloidal sol mixes completely, then dries under the condition of 85 DEG C, and drying course adopts first water-bath to steam near dry, then dries with drying box, is finally placed in Muffle furnace under the condition of 400 DEG C to calcine 3h, for subsequent use after cooling;

(4) at TiO ₂film area load NiFe ₂o ₄particle

Under room temperature, by weight, by the Ni (NO of 5.82 ₃) ₂6H ₂fe (the NO of O and 16.16 ₃) ₃9H ₂o joins in the absolute ethyl alcohol of 63.2, and magnetic agitation (100r/min) 60min, is adjusted to 9 by the NaOH solution of 20mol/L by pH value, then adds and is enclosed with TiO ₂the sepiolite of film, stirs (80r/min) 45min, then under the condition of 170 DEG C, reacts 18h, carry out Separation of Solid and Liquid, washing after cooling, finally dry under the condition of 80 DEG C, obtain described NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.

Embodiment 4

To the NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst is (hereinafter referred to as NiFe ₂o ₄/ TiO ₂/ sepiolite) carry out electron-microscope scanning, the test of solid ultraviolet-visible light spectrogram and examination of infrared spectrum, test result is shown in Fig. 1, Fig. 2 and Fig. 3.

Be at sepiolite surface parcel TiO on the left of Fig. 1 in the embodiment of the present invention 1 ₂scanning electron microscope (SEM) photograph after film, right side is NiFe ₂o ₄/ TiO ₂the scanning electron microscope (SEM) photograph of/sepiolite, as can be seen from Figure 1, sepiolite is through modified slabbing, and surface area is large, TiO ₂film is defined, TiO on sepiolite surface ₂film area load has granular NiFe ₂o ₄, therefore the present invention is conducive to increasing specific area, absorption property and photocatalytic activity.

In Fig. 2, a is existing TiO ₂/ sepiolite supported type photochemical catalyst is (hereinafter referred to as TiO ₂/ sepiolite) solid ultraviolet-visible light spectrogram, b is NiFe ₂o ₄/ TiO ₂the solid ultraviolet-visible light spectrogram of/sepiolite, as can be seen from Figure 2, TiO ₂there is wider energy gap (3.2eV), TiO ₂the energy gap of/sepiolite is reduced to 3.18eV, and NiFe ₂o ₄/ TiO ₂the energy gap of/sepiolite is reduced to 2.85eV further, shows the NiFe of gained of the present invention ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst has better catalytic activity to visible ray, thus improves the utilization ratio to visible ray.The NiFe of gained of the present invention also can be found out from Fig. 2 ₂o ₄/ TiO ₂the photoresponse scope of/sepiolite composite photo-catalyst extends to visible region.

In Fig. 3, a is the infrared spectrogram of sepiolite, and b is NiFe ₂o ₄/ TiO ₂the infrared spectrogram of/sepiolite, at 600-800cm ^-1time, NiFe ₂o ₄/ TiO ₂/ sepiolite compared with the infrared spectrogram of sepiolite, 668cm ^-1the absworption peak at place dies down, 755cm ^-1the Si-O at place _outwardabsworption peak disappears, this is because NiFe ₂o ₄/ TiO ₂the cause of the Ti-O in/sepiolite.1029cm ^-1the Si-O at place _instretching vibration peak intensity substantially remain unchanged.3570cm ^-1the absworption peak of the free O-H at place disappears, and 535cm ^-1the absworption peak of the Si-O-Mg at place weakens, and illustrates that the magnesium in sepiolite may be substituted, may make Si-O _{bridge falls}-Si increases, thus causes hole to increase, and absorption quantitative change is large.

Embodiment 5

The NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the photocatalytic degradation methylene blue solution measure of merit of/sepiolite composite photo-catalyst

Reaction initial conditions: methylene blue initial concentration 50mg/L, catalyst amount 0.4g, pH=5, it is carried out degradation experiment under ultraviolet catalytic reactor, degradation time is 60min, carries out visible spectrophotometer and measures its absorbance, measure methylene blue degradation efficiency every 10min sampling.Test result as shown in Figure 4, can be found out, the NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst degradation efficiency when 60min can reach 85.56%, and existing TiO ₂/ sepiolite supported type photochemical catalyst and CoFe ₂o ₄-TiO ₂doping photochemical catalyst at identical conditions degradation efficiency generally can only reach about 70%.

Embodiment 6

Existing TiO ₂/ sepiolite supported type photochemical catalyst, existing CoFe ₂o ₄-TiO ₂the NiFe of doping photochemical catalyst and the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the photocatalytic degradation methylene blue solution effectiveness comparison of/sepiolite composite photo-catalyst

Experiment condition: catalyst amount 1.0g, methylene blue initial concentration 4mg/L, pH=5, and degradation experiment is carried out under visible light catalytic reactor, degradation time is 120min, carries out measuring its absorbance, calculate methylene blue degradation efficiency every 20min sampling, result of the test is as shown in table 1, as can be seen from Table 1 the NiFe of the embodiment of the present invention 1 gained ₂o ₄/ TiO ₂the absorbance of/sepiolite composite photo-catalyst and degradation rate are all obviously better than existing TiO ₂/ sepiolite supported type photochemical catalyst and existing CoFe ₂o ₄-TiO ₂doping photochemical catalyst, this shows NiFe of the present invention ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst also has good photocatalytic degradation effect under visible light, and existing existing TiO ₂/ sepiolite supported type photochemical catalyst and existing CoFe ₂o ₄-TiO ₂doping photochemical catalyst photocatalytic degradation effect extreme difference under visible light, does not almost respond.

Table 1

Be to be understood that example as herein described and embodiment only in order to illustrate, those skilled in the art can make various amendment or change according to it, when not departing from Spirit Essence of the present invention, all belong to protection scope of the present invention.

Claims (4)

1. a NiFe ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, is characterized in that: composition comprises sepiolite, TiO ₂and NiFe ₂o ₄, sepiolite is carrier, TiO ₂be wrapped in sepiolite surface in membrane form, NiFe ₂o ₄load is at TiO in the form of granules ₂surface.

2. NiFe as claimed in claim 1 ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, is characterized in that: wherein the content of Ni is 1-2wt%, the content of Fe is 1.9-3.8wt%, the content of Ti is 12-18wt%, more than be divided into sepiolite.

3. NiFe as claimed in claim 2 ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst, is characterized in that: the content of the content of Ni to be the content of 1.5wt%, Fe be 2.8wt%, Ti is 15wt%, more than be divided into sepiolite.

4. NiFe as claimed any one in claims 1 to 3 ₂o ₄/ TiO ₂the preparation method of/sepiolite composite photo-catalyst, comprises the following steps:

(1) pretreatment of sepiolite

Sepiolite powder is broken into end, be placed in dust technology immersion 15-24h that concentration is 5-15%, filter, with water rinse to neutral post-drying, then at the temperature lower calcination 2-4h of 400-500 DEG C, filtered out by the sepiolite floating on water body upper position with water rinse, after dry, sieve gets particle diameter is that 100-125 object sepiolite powder are as carrier;

(2) TiO ₂the preparation of colloidal sol

Under room temperature, by volume part, the butyl titanate of 15-20 is fully dissolved in the absolute ethyl alcohol of 40-50, then the acetylacetone,2,4-pentanedione of 5-6 is added, obtain solution A, solution B is obtained after the distilled water of 0.75-1.0 and the absolute ethyl alcohol of 20-25 fully being mixed, under the condition constantly stirred, solution B is joined in solution A gradually, then with red fuming nitric acid (RFNA) or concentrated hydrochloric acid, pH value is adjusted to 4-5, stir l-2h, add the polyethylene glycol of 1-1.5, then under the condition of 40-65 DEG C, stir l-1.5h, obtain the TiO of yellow transparent ₂colloidal sol, by TiO ₂colloidal sol is ageing 12-15h at room temperature;

(3) at sepiolite surface parcel TiO ₂film

TiO ₂the number of plies of film is 1-3 layers, every layer of TiO ₂the formation method of film is: under room temperature, sepiolite is joined TiO ₂in colloidal sol, be stirred to and TiO ₂colloidal sol mixes completely, then dries under the condition of 70-85 DEG C, finally under the condition of 400-500 DEG C, calcines 1-3h, for subsequent use after cooling;

(4) at TiO ₂film area load NiFe ₂o ₄particle

Under room temperature, by weight, by the Ni (NO of 2.91-5.82 ₃) ₂6H ₂fe (the NO of O and 8.08-16.16 ₃) ₃9H ₂o joins in the absolute ethyl alcohol of 55.3-63.2, stirs 30-60min, by the NaOH solution of 5-20mol/L, pH value is adjusted to 9-10, then adds and be enclosed with TiO ₂the sepiolite of film, stirs 30-60min, then under the condition of 160-180 DEG C, reacts 18-24h, carries out Separation of Solid and Liquid, washing, finally dry under the condition of 70-85 DEG C, obtain described NiFe after cooling ₂o ₄/ TiO ₂/ sepiolite composite photo-catalyst.