CN101264925A - Method for preparing nano zinc sulfide - Google Patents

Abstract

The invention relates to a preparation method of nanometer zinc sulfide, which comprises the following steps: Na2S solution and ZnO solid powder are mixed; wherein, the mass ration of liquid to solid is 1-1.5 to 1, and the concentration of the Na2S solution is 1-3mol/L; before reaction, the mixture is dispersed by ultrasonic vibration, under the temperature of 70 to 90 DEG C, magnetic stirring reaction is conducted; after the reaction is completed, the product obtained is washed first by distilled water and then by absolute ethyl alcohol, and dried in vacuum in order to acquire nanometer ZnS powder. The preparation method of nanometer zinc sulfide has the advantages of simplicity, rapidity, and high purity as well as desirable performance of the nanometer zinc sulfide.

Description

A kind of preparation method of nanometer zinc sulfide

Technical field

The present invention relates to a kind of preparation method of nanometer zinc sulfide.

Background technology

ZnS is the II-VI group iii v compound semiconductor material with broad direct band gap, and its electroluminescent and photoluminescence efficiency are higher, is the important substrate material of present multicolor phosphor.The document of the preparation of relevant ZnS nano material and performance study was a lot of in recent years, summarize and get up to be divided into physics method and chemical method two big classes, wherein physical method mainly contains: vapour deposition process, sputtering method, low-temperature plasma method and vapor condensing method etc., this class methods plant and instrument complexity, the cost height; Chemical method mainly contains hydro-thermal solvent-thermal method, chemical precipitation method, microemulsion method, sol-gel method and LB embrane method etc., and raw material is more expensive in these methods, and uses a large amount of organic solvents, process control complexity, or uniform particles is poor, and particle easily bonds or reunion etc.Thereby be necessary to explore new synthetic method, in conjunction with the advantage of solid phase method and liquid phase method, prepare high purity, well behaved nano-zinc sulfide simply, quickly.

Xu J F etc. has invented a kind of novel preparation method of nanometer zinc sulfide: promptly utilize the gas evaporation technology to prepare the zinc fine particles of median size for 80nm earlier, highly active zinc fine particles surface when ingress of air understands that some is oxidized, is the Zn/ZnO nanopowder particles.An amount of Zn/ZnO powder is placed certain density Na ₂In the S solution, form suspension, at 50 ℃ of following sonic oscillations, the color of reaction system is white by black commentaries on classics, forms the ZnS precipitation, filters, washs, and obtaining median size is the spherical ZnS particulate of 40nm, and process is as follows:

2Zn+O ₂→2ZnO(1)

ZnO+Na ₂S+H ₂O→ZnS+2NaOH(2)

Analyzing aforesaid method can find: 1, this method essence is reaction (2), does not therefore need with nanometer zinc as raw material.Because the preparation nano zine oxide is simpler than the preparation nano zinc powder, cost is also lower, so can directly do raw material with nano zine oxide even common zinc oxide.2, the experimental result as this investigator shows, the easy kish zinc of products obtained therefrom, and purity is not high.

The present invention is a raw material with common zinc oxide powder and sodium sulphite directly first, utilizes the pre-dispersed effect of ultrasonic wave, has prepared the nano-zinc sulfide of excellent property.

Summary of the invention

Purpose of the present invention aims to provide a kind of simple, prepares high purity, well behaved method of nanometer zinc sulfide quickly.

The objective of the invention is to realize by following manner:

With Na ₂S solution mixes with the ZnO pressed powder, and wherein liquid-solid mass ratio is 1-1.5: 1, and Na ₂The concentration of S solution is 1-3mol/L; And before reaction, swing dispersion by the ultrasonic wave newspaper, and under 70-90 ℃ of temperature, carrying out the magnetic agitation reaction, the product that obtains after reaction is finished is used absolute ethanol washing with distilled water and back earlier, promptly gets the nanometer ZnS powder after the vacuum-drying.

Described ultrasonic wave Chun swings the preferred 10-20min of jitter time, most preferably 15min.

Preferred 1.5-2.5 of time hour of magnetic agitation reaction, most preferably 2 hours.

The most preferred reaction conditions of the present invention is: 80 ℃ of temperature of reaction, Na ₂S volumetric molar concentration 2mol/L, liquid-solid ratio 1.2:1.

The concrete implementation step of the present invention is:

The present invention's technical scheme in order to achieve the above object is at room temperature, preparation Na ₂S solution is with Na ₂S solution mixes with the ZnO pressed powder, after ultra-sonic oscillation are disperseed, change in the three-necked bottle then, and 2/3 of three-necked bottle submerged in the water-bath of certain temperature, magnetic agitation 1.5-2.5 hour, the product that obtains after reaction is finished is used absolute ethanol washing with distilled water and back earlier, promptly gets the nanometer ZnS powder after the vacuum-drying.Utilization XRD, SEM, IR and TG-DTA analyze the nano particle product, and the result shows the cubes zink sulphide of nano-zinc sulfide product for the well-crystallized, and mean particle size is 50 nanometers, and has good infrared light transmission and thermostability.Under ultrasonication, as raw material, can obtain the nano-zinc sulfide product with common ZnO.Experiment is proof also: the pattern of raw material does not have influence substantially to the pattern of product.

The present invention compares with prior preparation method, has following advantage: technology is simple, raw material is cheap, preparation cycle is short, and the nano particles that generates is evenly distributed.The present invention directly uses be the easier preparation of ratio nano zinc powder and more facile zinc oxide as the raw material production nano-zinc sulfide, practicality more economically.

In the present invention, under action of ultrasonic waves, directly with the synthetic preparation of zinc oxide reaction nanometer ZnS, reaction principle is as follows for we:

With (Δ _rG _m) _{T, P}Can differentiate the direction of reaction, but Δ _rG _m ^θThe limit that can only reflect reaction.In the ordinary course of things, Δ _rG _m ^θCan not be as the foundation of differentiating the Direction of Reaction, because Δ _rG _m ^θValue is that reactant and product all are in the gibbs free energy change value of reacting under the standard state, therefore can only judge the Direction of Reaction under these specified conditions.Under practical situation, use Δ _rG _mCriterion is judged the direction of reaction.For reaction:

ZnO(s)+S ^2-(aq)+H ₂O(l)＝ZnS(s，sph)+2OH ^-(aq)

${\mathrm{\&Delta;}}_r{G}_m={\mathrm{\&Delta;}}_r{G}_m^{\mathrm{\&theta;}}+{}_2\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A20081003112100071.png,A20081003112100072.png"\; state="\{\{state\}\}">R</figure-callout>}\mathrm{TIn}(C_{{\mathrm{OH}}^{-}}^2/C_{S^{2-}})$

According to isotherm formula

If Δ _rG _m＜0, then reaction can be carried out by forward; Otherwise reaction can not be carried out by forward.If Δ _rG _m ^θAbsolute value very big, Δ then _rG _m ^θSign just determined Δ basically _rG _mSymbol.Therefore, if Δ _rG _m ^θVery big negative value is arranged, then in the ordinary course of things, Δ _rG _mIt roughly also is negative value.Table 1 is the gibbs free energy changeization under the differing temps.Can judge by table 1, with ZnO and Na ₂It is possible that the S solution reaction prepares ZnS.

Gibbs free energy changeization during table 1 differing temps

Under the room temperature, ZnO, the ZnS solubility product in water is respectively 3 * 10 ^-18, 1 * 10 ^-24, ZnS more is insoluble in water than ZnO, thereby helps reaction forward and carry out.

Ultrasonic wave is the most remarkable to ZnS particulate particle size influences, the ZnS particle that the ultrasonic dispersing afterreaction obtains has all reached Nano grade, otherwise can only reach micron order: as Fig. 1 point A is the preceding ultrasonic dispersing of reaction 15 minutes, point B is for reacting the back ultrasonic dispersing 15 minutes, point C is each ultrasonic dispersing of reaction front and back 15 minutes, puts D, E, F, G, is respectively each ultrasonic dispersing of reaction front and back 5 minutes, 10 minutes, 20 minutes and 25 minutes.Fig. 2 (a), 2 (b), 2 (c) are respectively the ZnS size distribution figure that the laser particle size instrument records the preceding ultrasonic dispersing 15min of stirring in water bath, stirs back ultrasonic dispersing 15min and each ultrasonic dispersing 15min of stirring front and back.

Na ₂S reaction volumetric molar concentration is to the crucial factor of product purity influence.Fig. 3 is the Na of 1.125mol/L ₂The XRD figure spectrum of the ZnS that the S reaction obtains, Fig. 4 is the Na of 2.0mol/L ₂The XRD figure spectrum of the ZnS that the S reaction obtains.By collection of illustrative plates as seen, Na ₂S reaction volumetric molar concentration is that the ZnS that obtains of 1.125mol/L is impure, also has a small amount of unreacted ZnO, characteristic peak (111), (220), (311) that ZnS is arranged on the XRD figure spectrum, be the zincblende lattce structure of cubic, also shown characteristic peak (100), (002), (101), (110) of ZnO simultaneously; Na ₂S reaction volumetric molar concentration is that the ZnS purity that obtains of 2.0mol/L is higher, does not have other any impurity peaks substantially.

Description of drawings

Fig. 1 ultrasonic wave is to the influence of ZnS average particle size.

The ZnS size distribution figure that Fig. 2 laser particle size instrument records.

Fig. 3 Na ₂S reaction volumetric molar concentration is the XRD figure spectrum of 1.125mol/L ZnS powder.

Fig. 4 Na ₂S reaction volumetric molar concentration is the XRD figure spectrum of 2.0mol/L ZnS powder.

The SEM figure of the common ZnO raw material of Fig. 5.

The SEM figure of Fig. 6 nanometer ZnS product.

The SEM of Fig. 7 multiform looks ZnO raw material.

The SEM figure of Fig. 8 nanometer ZnS product.

Embodiment

Following examples are intended to illustrate the present invention rather than limitation of the invention further.The present invention can implement by described any mode of summary of the invention.

Embodiment 1

1) with 20mL Na ₂S (2.0mol/L) solution and 2g ZnO powder (pattern as shown in Figure 1), add in the 100ml beaker and mixing, liquid-solid ratio (L/S) 1.2: 1, ultra-sonic oscillation are disperseed 15min, pour in the there-necked flask of 100ml then immediately, connect condenser west tube, there-necked flask 2/3 submerges in 80 ℃ the water-bath, magnetic agitation 2h.With distilled water the product in the there-necked flask is dashed to the 200ml beaker immediately after reaction is finished, place the cold water chilling.Suction filtration, and be washed with distilled water to filtrate dropping CuSO ₄Nondiscoloration is used absolute ethanol washing three times again, last vacuum-drying, and the nanometer ZnS particulate pattern that obtains is as shown in Figure 2.

Embodiment 2

With 20mL Na ₂S (2.0mol/L) solution and 2g ZnO powder (pattern as shown in Figure 3), add in the 100ml beaker and mixing, liquid-solid ratio (L/S) 1.2: 1, ultra-sonic oscillation are disperseed 15min, pour in the there-necked flask of 100ml then immediately, connect condenser west tube, there-necked flask 2/3 submerges in 80 ℃ the water-bath, magnetic agitation 2h.With distilled water the product in the there-necked flask is dashed to the 200ml beaker immediately after reaction is finished, place the cold water chilling.Suction filtration, and be washed with distilled water to filtrate dropping CuSO ₄Nondiscoloration is used absolute ethanol washing three times again, last vacuum-drying, and the nanometer ZnS particulate pattern that obtains is as shown in Figure 4.

As seen SEM by product schemes, and the ZnS of the ZnO of different-shape reaction gained has close pattern.

Claims (4)

1, a kind of preparation method of nanometer zinc sulfide is characterized in that, with Na ₂S solution mixes with the ZnO pressed powder, and wherein liquid-solid mass ratio is 1-1.5: 1, and Na ₂The concentration of S solution is 1-3mol/L; And before reaction, swing dispersion by the ultrasonic wave Chun, and under 70-90 ℃ of temperature, carrying out the magnetic agitation reaction, the product that obtains after reaction is finished is used absolute ethanol washing with distilled water and back earlier, promptly gets the nanometer ZnS powder after the vacuum-drying.

2, a kind of preparation method of nanometer zinc sulfide according to claim 1 is characterized in that, it is 10-20min that described ultrasonic wave Chun swings jitter time.

3, a kind of preparation method of nanometer zinc sulfide according to claim 1 is characterized in that, the time of magnetic agitation reaction is 1.5-2.5 hour.

4, a kind of preparation method of nanometer zinc sulfide according to claim 1 is characterized in that, 80 ℃ of temperature of reaction, Na ₂S volumetric molar concentration 2mol/L, liquid-solid ratio 1.2: 1.

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