A kind of preparation method of porous calcium phosphate silver catalyst
Technical field
The present invention relates to a kind of preparation method of porous calcium phosphate silver catalyst, belong to sewage treatment area in the environment protection.
Background technology
Traditional water treatment method efficient is low, cost is high, have secondary pollution problems, the solution that waste water control can not get always.The development of nanotechnology and application probably thoroughly solve this difficult problem.Began to find TiO in 1972
2Oxidation activity is higher, and chemical stability is good, and to the human body toxicological harmless, cost is low, and is pollution-free, applied range, thereby paid attention to most, but TiO
2Large (the anatase octahedrite TiO for example of energy gap
2Energy gap Eg=3.2 eV), light that only can absorbing ultraviolet light district (wavelength is less than 387 nm), lower to the utilising efficiency of sun power.In June, 2010, the researchist of material research institution finds that Trisilver phosphate has the effect of photocatalyst, and the photoxidation effect is more than the decades of times of at present known various photocatalysts.
Hydrotalcite-based compound LDHs) be to pile up the compound that forms by interlayer anion and positively charged laminate.The hydrotalcite chemical structure of general formula is: [M
2+ 1-xM
3+X (OH)
2]
X+[(A
N-)
X/nMH
2O], M wherein
2+And M
3+Be respectively the divalence and the trivalent metal cation that are positioned on the main body laminate, such as Mg
2+, Ni
2+, Zn
2+, Mn
2+, Cu
2+, Co
2+, Pd
2+, Fe
2+Deng divalent cation and Al
3+, Cr
3+, Co
3+, Fe
3+All can form hydrotalcite Deng Tricationic; A
N –Be interlayer anion, can comprise inorganic anion, organic anion, title complex negatively charged ion, same many and heteropolyanion; X is M
3+/ (M
2++ M
3+) molar ratio, approximately be that 4:1 is to 2:1; M is the number of middle water molecule.Its similar is in brucite Mg (OH)
2, share seamed edge and form the main body laminate by octahedron.Be positioned at the divalent metal M on the laminate
2+Can be by the close trivalent metal cation M of ion half price in certain proportional range
3+Isomorphous substitution so that laminate is positively charged, interlayer exist can exchange negatively charged ion and the positive charge balance on the laminate so that the one-piece construction of LDHs is electric neutrality.The negatively charged ion of interlayer can be exchanged, and through a series of modifications, hydrotalcite material can obtain the many kinds of materials that performance is different.
Absorption is the important step of heterogeneous catalytic reaction, improves adsorption effect and is conducive to promote catalysis speed.Sorbent material is made porous material, be conducive to the solid-liquid separation of promoting absorption and can promote catalyzer.If the hole of this material can reach nano level, then can enlarge the specific surface area of catalyzer and bring into play nano effect, promote catalytic effect.
Summary of the invention
The object of the invention is to for the deficiencies in the prior art, propose a kind of preparation method of porous calcium phosphate silver catalyst, the method is that Trisilver phosphate is made porous material, is beneficial to absorption, not only can keeps its nano effect but also can be beneficial to precipitate and separate.
The technical solution used in the present invention is to adopt following steps:
1) be that the amount of 1:1 ~ 1:1.5 is configured to the solution that total concn is 2 ~ 4 mol/L with Silver Nitrate and aluminum nitrate according to mol ratio;
2) dripping mass concentration in this solution is 50% ~ 70%NaOH solution, regulate pH value to 8 ~ 10, during dropping under 300 ~ 400 rpm rapid stirring 60~120 minutes, 24 ~ 48 h wear out under 60 ~ 70 ℃ of conditions after being added dropwise to complete, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 2 ~ 3 times, 70 ~ 90 ℃ of lower oven dry;
3) with step 2) oven dry after solid join in the orthophosphate solution that concentration is 2 ~ 4 mol/L, add 20 ~ 200 g in every liter of orthophosphate solution, stir 2 ~ 6 h, aging 12 ~ 24 h under the room temperature, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 2 ~ 3 times, 70 ~ 90 ℃ of lower oven dry;
4) solid after the step 3) oven dry is calcined 2 ~ 3h in retort furnace under 450 ~ 550 ℃, obtain the porous calcium phosphate silver catalyst.
The invention has the beneficial effects as follows:
1. utilize the structure of catalyzer itself to form carrier, make carrier and catalyzing integrated, need not additional carrier, avoid supported catalyst to peel off from carrier surface.
2. catalyzer forms the nanometer layer structure, has nano effect, is conducive to bring into play catalytic effect.
3. laminate structure is conducive to form larger specific surface area, can promote absorption, and then make catalytic effect better.
Embodiment
Be that the amount of 1:1 ~ 1:1.5 is configured to the solution that total concn is 2 ~ 4 mol/L with Silver Nitrate and aluminum nitrate according to mol ratio first, dripping mass concentration in this solution is that 50% ~ 70%NaOH solution is regulated pH value to 8 ~ 10 again, during dropping under 300 ~ 400 rpm rapid stirring 60~120 minutes, 24 ~ 48 h wear out under 60 ~ 70 ℃ of conditions after being added dropwise to complete, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 2 ~ 3 times, 70 ~ 90 ℃ of lower oven dry, silver ions and aluminum ion form the layered solid of hydrotalcite-like compound in this process.
The solid that obtains is joined in the orthophosphate solution that concentration is 2 ~ 4 mol/L, add 20 ~ 200 g in every liter of orthophosphate solution, stir 2 ~ 6 h, aging 12 ~ 24 h under the room temperature, solid-liquid separation after aging the finishing is with solid washed with de-ionized water 2 ~ 3 times, 70 ~ 90 ℃ of lower oven dry, negatively charged ion in this process in phosphate radical and the houghite, the nitrate radical exchange forms the Trisilver phosphate structure; To dry solid and in retort furnace, under 450 ~ 550 ℃, calcine 2 ~ 3h, through calcining, obtain the porous calcium phosphate silver catalyst.
3 embodiment of the present invention below are provided:
Embodiment 1
With Silver Nitrate and and aluminum nitrate be that the amount of 1:1.5 is configured to the solution that total concn is 4 mol/L according to mol ratio; Dripping mass concentration in this solution is that 70%NaOH solution is regulated pH value to 10, during dropping under 400 rpm rapid stirring 120 minutes, after being added dropwise to complete under 70 ℃ of conditions aging 48 h, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 3 times, 90 ℃ of lower oven dry; The solid that obtains is joined in the orthophosphoric acid salt sodium radio-phosphate,P-32 solution that concentration is 4 mol/L, add 200 g in every liter of orthophosphate solution, stir 6 h, aging 24 h under the room temperature, solid-liquid separation after aging the finishing is with solid washed with de-ionized water 3 times, 90 ℃ of lower oven dry; Solid is calcined 2h in retort furnace, obtain the porous calcium phosphate silver catalyst under 550 ℃.
The porous calcium phosphate silver catalyst 0.5g that obtains is joined in the Xylene Red waste water that 500mL concentration is 30 mg/L, under the irradiation of 500w Metal-halogen lamp, react 25 min, percent of decolourization is 99.1%, and catalyst separating is simple, can reuse.
Embodiment 2
With Silver Nitrate and and aluminum nitrate be that the amount of 1:1 is configured to the solution that total concn is 2mol/L according to mol ratio; Dripping mass concentration in this solution is that 50%NaOH solution is regulated pH value to 8, during dropping under 300 rpm rapid stirring 60 minutes, after being added dropwise to complete under 60 ℃ of conditions aging 24 h, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 2 times, 70 ℃ of lower oven dry; The solid that obtains is joined in the orthophosphoric acid salt potassium phosphate solution that concentration is 2 mol/L, add 20 g in every liter of potassium phosphate solution, stir 2 h, aging 12 h under the room temperature, solid-liquid separation after aging the finishing is with solid washed with de-ionized water 2 times, 70 ℃ of lower oven dry; Solid is calcined 3h in retort furnace, obtain the porous calcium phosphate silver catalyst under 450 ℃.
The porous calcium phosphate silver catalyst 0.5g that obtains is joined in gold orange 7 waste water that 500mL concentration is 35 mg/L, under the irradiation of 500w Metal-halogen lamp, react 25 min, percent of decolourization is 98.7%, and catalyst separating is simple, can reuse.
Embodiment 3
With Silver Nitrate and and aluminum nitrate be that the amount of 1:1.5 is configured to the solution that total concn is 3 mol/L according to mol ratio; Dripping mass concentration in this solution is that 60%NaOH solution is regulated pH value to 9, during dropping under 350 rpm rapid stirring 80 minutes, after being added dropwise to complete under 70 ℃ of conditions aging 30 h, solid-liquid separation after aging the finishing, with solid washed with de-ionized water 3 times, 80 ℃ of lower oven dry; The solid that obtains is joined in the sodium radio-phosphate,P-32 solution that concentration is 4 mol/L, add 100 g in every liter of sodium radio-phosphate,P-32 solution, stir 4h, aging 18h under the room temperature, solid-liquid separation after aging the finishing is with solid washed with de-ionized water 3 times, 80 ℃ of lower oven dry; Solid is calcined 2h in retort furnace, obtain the porous calcium phosphate silver catalyst under 500 ℃.
The porous calcium phosphate silver catalyst 0.5g that obtains is joined in the rose red b waste water that 500mL concentration is 30 mg/L, under the irradiation of 500w Metal-halogen lamp, reaction 25min, percent of decolourization is 99.2%, catalyst separating is simple, can reuse.