A kind of preparation and application process thereof of visible-light response type chlorine oxygen bismuth photochemical catalyst
Technical field
Preparation and the application process of a kind of visible-light response type chlorine of the present invention oxygen bismuth photochemical catalyst, belong to environmental chemical engineering photocatalysis water-treatment technology field, be specifically related to a kind of structure regulating action of utilizing iodide ion, the absorption spectrum of chlorine oxygen bismuth photochemical catalyst is widened visible region, is the technical scheme of feedstock production visible-light response type chlorine oxygen bismuth photochemical catalyst and application process thereof with sodium bismuthate, hydrochloric acid and KI.
Background technology
Along with the development of dye industry, its factory effluent has become one of current most important pollution source of water body.Dye wastewater has that color is dark, complicated component, the COD value is higher and characteristics such as difficult degradation, brings serious harm to ecological environment.The method of dye wastewater treatment using mainly contains at present: absorption method, membrane separation process, photocatalytic oxidation, electrochemical oxidation process, ultrasonic degradation technology etc.Photocatalytic oxidation has characteristics such as efficient energy-saving, contaminant degradation be thorough.TiO
2Be the photochemical catalyst that is most widely used, the light generation less than 387 nm responds to wavelength but its wideer band gap (~3.2 eV) makes it, and the wavelength that accounts for solar energy 45~50% is the not response of visible light of 400~750 nm.The highly anisotropic layer structure of chlorine oxygen bismuth (BiOCl) is convenient to the separation in light induced electron hole, has guaranteed the good stable photocatalytic activity of BiOCl.But broad-band gap (~3.4 eV) has limited the utilization of the visible light of BiOCl equally.Therefore, the band-gap energy of BiOCl is reduced, thereby can more fully effectively utilize solar energy to become the focus that people pay close attention to.At present, the correlative study of more existing enhancing BiOCl visible light response activity is by wide coverage.Xiong etc. have reported in the auxiliary employing down of sweet mellow wine Hydrothermal Preparation foursquare two-dimentional BiOCl nanometer sheet, and the band gap of this catalyst obviously reduces (~2.92 eV).This catalyst shows good photocatalytic activity to rhodamine B under visible light, and catalyst amount is 0.5 gL
-1The time, 10
-5MolL
-1The degraded fully in 8 minutes of rhodamine B solution (RSC Advances, 2011,1:1542-1553).The irradiation of people such as Ye by ultraviolet light is reduced to 2.65 eV with the band gap of BiOCl from 3.5 eV.This is because the irradiation of ultraviolet light makes the BiOCl caltalyst form the oxygen room in mutually.Under radiation of visible light, this catalyst to the degrading activity of the rhodamine B catalyst ground activity before than UV-irradiation improved nearly 20 times (Phys. Chem. Chem. Phys., 2012,14:82-85).People such as Chen are raw material with bismuth trichloride and nitric acid, have prepared BiOCl(~2.87 eV under the corrective action of l-lysine) photochemical catalyst.Narrow band gap may be because the pattern of nano flower-like and high (110) crystal face that exposes.After λ 〉=435 nm light sources shine 50 min, 10 mgL
-1RhB decolours fully, and its degradation rate constant reaches 0.1186 min
-1(Catalysis Communications, 2012,23:54-57).
Summary of the invention
The preparation of a kind of visible-light response type chlorine of the present invention oxygen bismuth photochemical catalyst and the purpose of application process are at the wide problem of BiOCl photochemical catalyst band gap, a kind of strong reducing property and selective absorption performance of utilizing iodide ion proposed, the BiOCl crystal is grown along the particular crystal orientation preferentially, and the absorption spectrum of BiOCl photochemical catalyst widened visible region, with sodium bismuthate, hydrochloric acid and KI are raw material, by redox, precipitation, separate, washing and drying steps prepare the method for visible-light response type chlorine oxygen bismuth photochemical catalyst and application thereof, this method is fully effectively utilized solar energy, and can solve environmental pollution problems.
The preparation method of a kind of visible-light response type chlorine of the present invention oxygen bismuth photochemical catalyst, it is characterized in that it being a kind of strong reducing property and selective absorption performance of utilizing iodide ion, the BiOCl crystal is grown along the particular crystal orientation preferentially, and the absorption spectrum of BiOCl photochemical catalyst widened visible region, be raw material with sodium bismuthate, hydrochloric acid and KI, prepare the method for visible-light response type chlorine oxygen bismuth photochemical catalyst by redox, precipitation, separation, washing and drying steps, its concrete preparation process is:
(1) sodium bismuthate is positioned in the absolute ethyl alcohol, under magnetic agitation, disperses 1~1.5 h; Prepare 1.2 molL
-1Hydrochloric acid 100 mL, and take by weighing with the hydrochloric acid solution of preparing in the KI of chlorion equimolar amounts be dissolved in 1.2 molL that prepare
-1In the hydrochloric acid solution, it is standby to form hydrochloric acid-KI mixed solution;
(2) the standby hydrochloric acid-KI mixed solution that with the speed that dripped 1mL in 8~10 minutes step (1) is prepared under magnetic agitation joins in sodium bismuthate-absolute ethyl alcohol suspension, stirring reaction times 1.5~2 h, reaction temperature control is at 20~20.5 ℃, and it is standby to make aaerosol solution;
(3) the standby aaerosol solution that step (2) is obtained filters, and filter cake usefulness distilled water and absolute ethanol washing three times are dried under 40~50 ℃ of temperature then, namely make visible-light response type BiOCl photochemical catalyst.
The preparation method of above-mentioned a kind of visible-light response type chlorine oxygen bismuth photochemical catalyst, it is characterized in that strong reducing property and selective absorption performance by iodide ion, make BiOCl crystal preferred growth on the particular crystal direction, and the band gap of BiOCl is decreased to 2.3 eV, thereby make it not only produce response to ultraviolet light, simultaneously visible light is also produced response.
The application process of above-mentioned a kind of visible-light response type chlorine oxygen bismuth photochemical catalyst, it is characterized in that prepared visible-light response type BiOCl photochemical catalyst is used for the degradation water organic matter, the particularly processing of the harmful hardly degraded organic substance rhodamine B of trace toxic or methylene blue in the water, concrete degradation step is:
Step (1): accurately take by weighing rhodamine B or the methylene blue solid of 7 mg, it is dissolved in the distilled water, and is settled to 1000 mL, make 7 mgL
-1Rhodamine B or methylene blue solution;
Step (2): accurately pipette rhodamine B that 100 mL steps (1) obtain or methylene blue solution to reactor with pipette, and add 0.03~0.05 g BiOCl photochemical catalyst, temperature of reaction system control is at 20~20.5 ℃, under half-light, adsorb 1~1.5 h earlier, make it reach the adsorption/desorption balance;
Step (3): with the 350W xenon lamp as visible light source, step (2) gained solution is carried out the photocatalytic degradation reaction under illumination, every interval 5~30min time sampling, and measure the absorbance of rhodamine B or methylene blue and calculate its conversion ratio with UV-VIS spectrophotometry.
Preparation method and the advantages of application thereof of a kind of visible-light response type chlorine of the present invention oxygen bismuth photochemical catalyst are:
(1) it is wide to have remedied chlorine oxygen bismuth photochemical catalyst band gap, can not take full advantage of the defective of solar energy.The band gap of chlorine oxygen bismuth is decreased to 2.3 eV from 3.4 eV, has increased the utilization ratio of chlorine oxygen bismuth photochemical catalyst to visible light;
(2) adopt conventional inorganic raw material as reactant, raw material is cheap and easy to get; Preparation process remains on room temperature, does not need high-temperature roasting, and the preparation condition gentleness is simple; This preparation method is environmentally friendly simultaneously, does not produce the poisonous and harmful accessory substance;
(3) visible-light response type chlorine oxygen bismuth photochemical catalyst has good photocatalytic activity under visible light, and can utilize solar energy more fully efficiently, and this utilizes significant to environmental improvement and green energy resource.
Description of drawings
Fig. 1 is the XRD figure of the visible-light response type chlorine oxygen bismuth photochemical catalyst of embodiment of the present invention 1 preparation.
Fig. 2 is the DRS figure of the visible-light response type chlorine oxygen bismuth photochemical catalyst of embodiment of the present invention 1 preparation.
The specific embodiment
Embodiment 1
Take by weighing 3.16 g sodium bismuthates, it is dispersed in the 40 mL absolute ethyl alcohols.Prepare 1.2 molL
-1Watery hydrochloric acid 40 mL, take by weighing with institute complex salt acid solution in the KI of chlorion equimolar amounts be dissolved in this hydrochloric acid and form hydrochloric acid-KI mixed solution, this mixed solution is joined in sodium bismuthate-absolute ethyl alcohol suspension with the speed that dripped 1mL in 8 minutes, obtain aaerosol solution behind stirring reaction 1.5 h.Aaerosol solution is carried out suction filtration, and with distilled water and absolute ethanol washing filter cake three times, 40 ℃ of oven dry down, namely get visible-light response type BiOCl photochemical catalyst then.
The gained photochemical catalyst is used for oxidation processes rhodamine B or aqueous solution of methylene blue.Degradation step is:
Step (1): accurately take by weighing rhodamine B or the methylene blue solid of 7 mg, it is dissolved in the distilled water, and is settled to 1000 mL, make 7 mgL
-1Rhodamine B or methylene blue solution;
Step (2): accurately pipette rhodamine B that 100 mL steps (1) obtain or methylene blue solution to reactor with pipette, and add 0.03 g BiOCl photochemical catalyst, temperature of reaction system control is adsorbed 1 h earlier at 20~20.5 ℃ under half-light, make it reach the adsorption/desorption balance;
Step (3): as visible light source, step (2) gained solution is carried out the photocatalytic degradation reaction under illumination with xenon lamp (350W).Every interval 5~30min time sampling, and measure the absorbance of rhodamine B or methylene blue and calculate its conversion ratio with UV-VIS spectrophotometry, the results are shown in Table 1.
Embodiment 2
Take by weighing 6.32 g sodium bismuthates, it is dispersed in the 80 mL absolute ethyl alcohols.Prepare 1.2 molL
-1Watery hydrochloric acid 80 mL, take by weighing with institute complex salt acid solution in the KI of chlorion equimolar amounts be dissolved in this hydrochloric acid and form hydrochloric acid-KI mixed solution, this mixed solution is joined in sodium bismuthate-absolute ethyl alcohol suspension with the speed that dripped 1mL in 10 minutes, obtain aaerosol solution behind stirring reaction 2 h.Aaerosol solution is carried out suction filtration, and with distilled water and absolute ethanol washing filter cake three times, 50 ℃ of oven dry down, namely get visible-light response type BiOCl photochemical catalyst then.
The gained photochemical catalyst is used for oxidation processes rhodamine B or aqueous solution of methylene blue.Degradation step is:
Step (1): accurately take by weighing rhodamine B or the methylene blue solid of 7 mg, it is dissolved in the distilled water, and is settled to 1000 mL, make 7 mgL
-1Rhodamine B or methylene blue solution.
Step (2): accurately pipette rhodamine B that 100 mL steps (1) obtain or methylene blue solution to reactor with pipette, and add 0.03 g BiOCl photochemical catalyst, temperature of reaction system control is adsorbed 1.5 h earlier at 20~20.5 ℃ under half-light, make it reach the adsorption/desorption balance;
Step (3): as visible light source, step (2) gained solution is carried out the photocatalytic degradation reaction under illumination with xenon lamp (350W).Every interval 5~30min time sampling, and measure the absorbance of rhodamine B or methylene blue and calculate its conversion ratio with UV-VIS spectrophotometry, the results are shown in Table 1.
Embodiment 3
Take by weighing 1.58 g sodium bismuthates, it is dispersed in the 20 mL absolute ethyl alcohols.Prepare 1.2 molL
-1Watery hydrochloric acid 20 mL, take by weighing with institute complex salt acid solution in the KI of chlorion equimolar amounts be dissolved in this hydrochloric acid and form hydrochloric acid-KI mixed solution, this mixed solution is joined in sodium bismuthate-absolute ethyl alcohol suspension with the speed that dripped 1mL in 9 minutes, obtain aaerosol solution behind stirring reaction 1.5 h.Aaerosol solution is carried out suction filtration, and with distilled water and absolute ethanol washing filter cake three times, 45 ℃ of oven dry down, namely get visible-light response type BiOCl photochemical catalyst then.
The gained photochemical catalyst is used for oxidation processes rhodamine B or aqueous solution of methylene blue.Degradation step is:
Step (1): accurately take by weighing rhodamine B or the methylene blue solid of 7 mg, it is dissolved in the distilled water, and is settled to 1000 mL, make 7 mgL
-1Rhodamine B or methylene blue solution.
Step (2): accurately pipette rhodamine B that 100 mL steps (1) obtain or methylene blue solution to reactor with pipette, and add 0.05 g BiOCl photochemical catalyst, temperature of reaction system control is adsorbed 1.5 h earlier at 20~20.5 ℃ under half-light, make it reach the adsorption/desorption balance;
Step (3): as visible light source, step (2) gained solution is carried out the photocatalytic degradation reaction under illumination with xenon lamp (350W).Every interval 5~30min time sampling, and measure the absorbance of rhodamine B or methylene blue and calculate its conversion ratio with UV-VIS spectrophotometry, the results are shown in Table 1.
It is pure that used medicine and reagent is analysis in the above embodiment.
The degraded situation of table 1 visible-light response type BiOCl photochemical catalyst under different embodiments