The composite photo-catalyst g-C of efficient removal persistent organic pollutants
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4the preparation of-bismuth ferrite and application thereof
Technical field
The invention belongs to field of Environment Protection, be specifically related to the composite photo-catalyst g-C efficiently removing persistent organic pollutants
3n
4the preparation of-bismuth ferrite and application thereof.
Background technology
In recent years, environmental pollution badly influences daily life, therefore how effectively to eliminate the organic pollution to human hazard, has become the focus that scientific circles pay close attention to.Traditional administering method not only poor effect, and not environmentally, easily secondary pollution is caused to environment.Photocatalysis technology, in solution problem of environmental pollution, shows great application potential.And, because Photocatalitic Technique of Semiconductor self has plurality of advantages, as: cheap, nontoxic, energy consumption is low.Therefore, this technology obtains extensive research.
Bismuth ferrite, as a kind of novel conductor photocatalysis material, can be used for degradable organic pollutant.BFO energy gap, at 2.1eV-2.9eV, has good response in visible-range, with TiO
2compare, more effectively can utilize visible ray, but its photocatalytic activity is lower, this just hinders it as the application in photochemical catalyst realization.The factor affecting material light catalysis activity mainly contains three aspects: the specific area of (1) catalysis material; (2) photochemical catalyst produces the ability of electron-hole pair; (3) electronics and the hole separation rate on material.The photocatalytic activity that bismuth ferrite is lower is also mainly subject to the restriction of these factors.For this reason, improve the photocatalytic activity of bismuth ferrite, improve its light absorpting ability, the method for improvement has multiple, that relatively commonly uses at present has following three kinds: (1) improves the specific area of material by the bismuth ferrite preparing different-shape and structure, thus improves its photocatalytic activity; (2) by carrying out metal or doped metallic oxide, as Zn, Mn, La etc. to bismuth ferrite material.Thus effectively strengthen absorbing properties, and then improve the catalytic performance of material in photocatalytic applications; (3) the secret band structure of ferrous acid can be improved by ion doping, increase carrier concentration, reduce electron-hole pair recombination rate, the photocatalysis performance that ferrous acid is secret can not only be improved, its magnetic can also be strengthened.But its photo-quantum efficiency is still to be strengthened, and bismuth ferrite exists photoetch.Although can be improved the cycle performance of material by the modification of material, its visible light catalysis activity still has much room for improvement.
G-C
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4be considered to a kind of sustainable, non-metal semiconductive photochemical catalyst that can utilize Visible Light Induced Photocatalytic pollutant, good stability, nontoxic, can photolysis water hydrogen, its band gap width is about 2.7eV, and energy absorbing wavelength is less than the light of 460nm, in photocatalysis and degraded, have potential application.But single g-C
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4itself can only absorb the visible ray of small part, thus independent g-C
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4photocatalytic activity not high, which has limited its practice.
Therefore, in conjunction with g-C
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4with the respective advantage of bismuth ferrite material, sol-gal process one step is adopted to prepare g-C
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4-bismuth ferrite composite photocatalyst material, by this composite light degradation persistent organic pollutants bisphenol-A, has good photocatalysis effect, and can repeatedly recycle, and has important practical guided significance to degraded persistent organic pollutants aspect.
Summary of the invention
The photo-generated carrier recombination rate that the object of the invention is to solve photochemical catalyst in current photocatalysis field is high, the low and g-C of a kind of efficiency light response of exploitation of quantum efficiency
3n
4-bismuth ferrite composite photo-catalyst and preparation method thereof, the method adopts sol-gal process synthesis.By sol-gal process one-step synthesis g-C
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4-bismuth ferrite composite photo-catalyst.And by this catalyst application in photocatalysis treatment persistent organic pollutants.
The present invention is achieved like this, a kind of composite photo-catalyst g-C of efficient removal persistent organic pollutants
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4the preparation method of-bismuth ferrite, is characterized in that method step is as follows;
(1) with bismuth source and source of iron for raw material, the two dissolved respectively in organic solvent, normal temperature lower magnetic force stirs until dissolve completely, mixing and stirring;
(2) add a certain amount of melamine, until be uniformly dissolved, heating obtains sol solution, and continue to stir certain hour, dry 24-48 hour at 80-100 DEG C of temperature, obtains xerogel;
(3) xerogel grinding is transferred in Muffle furnace and calcines 3-5 hour, be cooled to room temperature, after grinding sample.
Further, described bismuth source is bismuth nitrate and hydrate thereof, and source of iron is ferric nitrate and hydrate thereof.
Further, described organic solvent is EGME.
Further, described certain hour is 0.5-1 hour.
Further, in Muffle furnace, calcining heat is 500-550 DEG C.
G-C of the present invention
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4the application of-bismuth ferrite composite photo-catalyst is: employing xenon lamp is light source, in environment, persistent organic pollutants bisphenol-A is as light degradation model, composite and bisphenol-A solution are fully mixed with the bisphenol-A organic pollution in photocatalytic degradation Simulated Water environment, bisphenol-A in efficient removal water environment, the bisphenol-A removed in 2 hours in water environment reaches more than 90% (concentration is 10mg/L), photocatalytic activity is good, and stable performance, is successful one-step synthesis method g-C first
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4-bismuth ferrite composite photo-catalyst, reacted catalyst can recycled for multiple times, has great importance and good development prospect in waste water control.
G-C provided by the invention
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4the preparation method of-bismuth ferrite composite photo-catalyst and its original had advantage as follows:
1. by sol-gal process one-step synthesis method g-C
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4-bismuth ferrite composite photo-catalyst;
2.g-C
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4introducing be conducive to the right separation of photo-generate electron-hole, and the specific area of material can be improved thus can fully contact with organic pollution;
3. take xenon lamp as light source, without the need to oxidant applying and auxiliary agent, the persistent organic pollutants in water can be removed efficiently;
4. the preparation of catalyst has good repeatability, and catalytic activity is high, and abundant raw material is easy to get, and facilitates industrialization promotion.
Accompanying drawing explanation
Fig. 1 is g-C
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4the XRD figure of-bismuth ferrite composite photo-catalyst, has as can be seen from the figure successfully synthesized g-C
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4-bismuth ferrite composite photo-catalyst.
Fig. 2 is g-C
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4the infrared spectrum of-bismuth ferrite composite photo-catalyst, can confirm g-C in composite further from spectrogram
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4existence.
Fig. 3 is g-C
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4the uv drs figure of-bismuth ferrite composite photo-catalyst, as can be seen from the figure composite there occurs obvious red shift, and explanation better can utilize visible ray.
Fig. 4 is g-C
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4the design sketch of the light degradation bisphenol-A of-bismuth ferrite composite photo-catalyst, as can be seen from the figure composite reached 90% to bisphenol-A degradation effect in 2 hours, compared single bismuth ferrite and g-C
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4be significantly improved.
Detailed description of the invention
Realizing key technology of the present invention is prepare g-C
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4-bismuth ferrite composite photo-catalyst, for achieving the above object, the invention provides following technical scheme:
G-C
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4the preparation method of-bismuth ferrite composite photo-catalyst, the method comprises:
(1) make bismuth salt and molysite dissolve in organic solvent respectively, form the organic solution of bismuth-containing salt and the organic solution containing molysite;
(2) fully mix by the organic solution of the bismuth-containing salt of same ratio in (1) with containing the organic solution of molysite, the magnetic agitation regular hour, form bismuth-containing salt and the mixed organic solvents containing molysite;
(3) a certain amount of melamine is added by the mixed solution of (2);
(4) mixed organic solvents in (3) is carried out evaporate to dryness, obtain xerogel;
(5) the xerogel grind into powder in (4) be transferred in Muffle furnace calcine, be cooled to room temperature, grind to obtain sample:
Bismuth salt described in step (1) is bismuth nitrate and hydrate thereof, and described molysite is ferric nitrate and hydrate thereof, and described organic solution is EGME;
The magnetic agitation regular hour described in step (2) is 0.5-1 hour;
A certain amount of melamine that adds described in step (3) is 30-50%;
The temperature of organic solution being carried out evaporate to dryness described in step (4) is 80-100 DEG C, and the evaporate to dryness time is 24-48 hour;
Described in step (5) powder is carried out calcination processing time temperature be 500-550 DEG C, the time is 3-5 hour;
The g-C that said method is prepared
3n
4-bismuth ferrite composite photo-catalyst is for the treatment of the persistent organic pollutants in environment.
Embodiment one
First Bi (the NO of 0.005mol is taken
3)
35H
2o and 0.005molFe (NO
3)
39H
2o sample is dissolved in the EGME solution of 30ml respectively, is uniformly dissolved at normal temperatures under magnetic agitation, will containing Bi (NO
3)
3eGME solution and 0.005molFe (NO
3)
3eGME solution mixing, normal temperature lower magnetic force stirs 30 minutes, add the melamine of 0.01mol, after being uniformly dissolved, heating is stirred to colloidal sol shape, the sample of colloidal sol shape is transferred to baking oven 90 DEG C of dryings 24 hours, obtain gel, by being transferred in Muffle furnace 550 DEG C of calcinings 4 hours after gel abrasive powdered, be cooled to room temperature, after grinding sample.Take the above-mentioned catalyst of 0.100g, joining 100mL initial concentration is in the bisphenol-A organic pollution of 10mg/L, dark reaction carried out light degradation after 40 minutes, light source power is 300W, from liquid level 15cm, sampling in every 20 minutes, by the absorbance of spectrophotometer measurement sample, light-catalyzed reaction, after 120 minutes, reaches 90% to the clearance of persistent organic pollutants bisphenol-A.