KR20020007800A - Chalconitride Glass Electrodes for Selective Heavy Metal Ions and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A heavy metal selective glass electrode is provided, which is mechanically and chemically stable by inducing modification of structure of chalcogenide glass to strengthen its reticulate structure. Also, a method for producing such a heavy metal selective glass electrode having a rapid response speed and a wide applicable temperature at a low cost is provided. CONSTITUTION: The glass electrode comprises a chalcogenide glass prepared using Ge-Se-Te-Si3N4 as starting materials being doped with CdS and HgTe to form a thin film of Ge-Se-Te-Si3N4-CdS/HgTe. A mother glass is prepared by injecting Ge, Se, Te and Si3N4 to a quartz ample, followed by sealing; placing the ample in a horizontal tube furnace wherein the ample is melted, followed by rapid cooling to form parent glass. The glass electrode is prepared by doping the mother glass with CdS/HgTe and injecting to a quartz ample, followed by sealing; placing the ample in a horizontal tube furnace wherein the ample is melted, followed by rapid cooling to form glass for electrode; grinding the resulting glass for electrode and compounding a coating solution in amine; and forming a thin film by a spin coating method, followed by thermal treatment optimally at 200 deg.C.

Description

{Chalconitride Glass Electrodes for Selective Heavy Metal Ions and manufacturing method}

The present invention provides a heavy metal ion selective electrode material that is mechanically and chemically stable by strengthening the network structure of a glass electrode applied as a heavy metal ion sensor with excellent electrical conductivity and ion conductivity, and to form a thin film for maintaining ion selectivity and sensitivity. The present invention provides a method of manufacturing a heavy metal ion selective electrode material capable of shortening the response speed, increasing the use temperature range, and manufacturing a thin film at low cost.

With the development of industry and civilization, the emission of various pollutants increased, which caused environmental pollution, and their harmful effects on the human body and ecosystem caused malformation and alteration of cancer and water.

Among these environmental pollutions, in particular, water pollution has reached a fairly serious level as being directly related to survival.

In order to prevent water pollution, regular inspections on wastewaters discarded by domestic sewage and industry are carried out.However, some of the wastewaters that are discharged unauthorizedly flow out to the rivers and the seas in an instant, so the pollution degree at the time of inspection and the pollution degree after inspection are different. Indicates.

In addition, since the pollutants released during the inspection period are unprotected, fast inspection time is most important in measuring the water pollution.

Therefore, it was required to manufacture a chemical sensor that is quick to respond to harmful substances and is easy to carry. Ion-selective electrodes have been introduced as chemical sensors that meet these requirements.

Ion-selective electrodes have a high degree of selectivity for single ions or pairs of ions by indicating the concentration of a particular ion in a solution through the electrode potential. In other words, it is a device that immediately converts the amount of harmful substances such as heavy metal ions in the wastewater into electrical signals. Conditions for ion-selective electrode materials include selectivity to selectively find the ions to be detected accurately in the presence of interfering ions, sensitivity to detect even small amounts, and long-term conditions in a pH <2 environment. Should be stable upon exposure.

Heavy metal ion selective electrode materials currently used are polymers such as polyvinyl chloride or epoxy, and the measurement range is 0.1 to 10 ^-5 M, the operating temperature is 0 to 50 ℃, and the response time is about 30 seconds. Many restrictions apply. Recently, attention has been focused on chalcogenide glass, which has excellent ionic and electrical conductivity and is chemically very stable as a new material, and has a high sensitivity of metallurgical selective electrode due to faster redox reaction in aqueous solution than conventional electrodes. The possibility as a material has been proposed, and expectations have been raised for practical use. However, chalcogenide glass has a weak thermal and mechanical properties compared to oxide glass, and there is a problem that it must be manufactured at a very high cost because a method such as chemical vapor deposition or sputtering by plasma sputtering should be used when manufacturing a thin film.

Accordingly, an object of the present invention is to provide a mechanically and chemically stable heavy metal ion selective electrode material by inducing a change in the chalcogenide glass structure applied as a heavy metal ion sensor with excellent electrical and ionic conductivity to strengthen the network structure. .

Another object of the present invention is to reduce the response speed and increase the operating temperature range in terms of the formation of a thin film for maintaining ion selectivity and sensitivity, which is important in heavy metal ion selective electrode materials, and to produce a thin film at low cost in process. It is to provide a method for producing a heavy metal ion selective electrode material.

Features of the present invention for achieving this object,

A heavy metal ion selective electrode material based on chalcogenide glass having excellent ion and electrical conductivity, chemical stability, fast redox reaction in aqueous solution, and excellent sensitivity,

The heavy metal ion selective electrode material,

CdS and HgTe are doped into the chalconitrile mother glass prepared using Ge-Se-Te-Si3N4 as a starting material, and a Ge-Se-Te-Si3N4-CdS / HgTe thin film is formed.

Another feature of the invention,

In the manufacturing method of the heavy metal ion selective electrode for using chalcogenide glass which is excellent in ion and electrical conductivity, is chemically stable, and has quick sensitivity and redox reaction in aqueous solution, as an ion selective electrode material,

The manufacturing method of the heavy metal ion selective electrode material,

Preparing a mother glass by charging and sealing a quartz ampoule using Ge, Se, Te, and Si 3 N 4 as starting materials to melt and quench in a horizontal tube;

Preparing a glass for an electrode by doping CdS / HgTe into the mother glass manufactured through the above step, charging and sealing a quartz ampoule, melting and quenching in a horizontal tube;

The electrode glass prepared in the above step is pulverized to synthesize a coating solution, and the thin film is prepared by the spin coating method, characterized in that it comprises a thin film forming step of the electrode glass.

1 is a heavy metal ion selective electrode using glass

2 is a schematic view of a thin film of a heavy metal ion selective material

3 is a manufacturing process diagram of a heavy metal ion selective glass thin film according to the present invention

4 is a cross-sectional view of a Ge-Se-Te-Si3N4-CdS glass thin film according to the present invention.

5 is a cross-sectional view of a Ge-Se-Te-Si3N4-HgTe glass thin film according to the present invention.

Figure 6 shows an embodiment of the present invention, the potential difference vs. response time curve of Ge-Se-Te-Si3N4-CdS glass electrode in Cd2 + aqueous solution

Figure 7 shows an embodiment of the present invention, the potential difference vs. response time curve of Ge-Se-Te-Si3N4-HgTe glass electrode in Hg2 + aqueous solution

8 is a graph of stability evaluation according to the present invention, the potential difference curve according to the measurement time of the Ge-Se-Te-Si3N4-CdS / HgTe glass electrode

* Description of the symbols for the main parts of the drawings *

1: Ge-Se-Te-Si3N4-CdS / HgTe thin film

2: Reference Solution in the Quartz Tube

3: SiO2 Tube

4: Platinum wire (Pt Rod)

5: silicone wafer

Hereinafter, the present invention will be described with reference to the drawings.

In the present invention, in order to improve the thermal and mechanical properties of the chalcogenide glass, Si3N4 is added to the glass to prepare a chalconitride glass of which the network structure of the glass is strengthened, and amine is used as a solvent. A thin film was prepared by spin coating to prepare a heavy metal ion selective electrode. The response time of the prepared heavy metal ion selective electrode for Cd 2+ and Hg 2+ ions, respectively, was shorter than that of conventional materials.

1 is a schematic diagram of a heavy metal ion selective electrode, symbol 1 is a Ge-Se-Te-Si3N4-CdS / HgTe thin film, 2 is a reference solution contained in a SiO2 tube, 3 is a SiO2 tube containing a standard solution and a platinum wire is erected, and 4 is a platinum rod.

FIG. 2 is a schematic view of the thin film of the present invention manufactured by spin coating, and shows a Ge-Se-Te-Si 3 N 4 -Cd-S / HgTe thin film 1 deposited on the surface of a silicon wafer 5.

Figure 3 is a flow chart of the glass thin film manufacturing process proceeds to the thin film of the mother glass production-electrode glass production-electrode glass, Ge-Se-Te-Si3N4-CdS / HgTe thin film (1) of the present invention is prepared by spin coating do.

The manufacturing process is first made of high purity (99.999%) Ge, Se, Te, Si3N4 as a starting material (S101), and charged into a silica ampoule (Ampoul) in order to manufacture the mother glass chalconitride glass After that, the suture is performed under a pressure of 10 ⁻⁵ torr or less (S102). The sealed quartz ampoule is charged into a horizontal tube furnace, melted at 850 ° C. for 24 hours at a temperature increase rate of 1 K / min, and quenched to prepare a glass (S103).

After preparing the mother glass, doped CdS and HgTe in the mother glass prepared for the production of electrode glass (S201), charged in a quartz ampoule, sutured under a pressure of 10 ^-5 torr or less (S202), similar to the above process, That is, the glass is manufactured by melting at 1000 ° C./1050° C. for 10 hours at a temperature rising rate of 1 K / min, respectively.

The glass forming region of the prepared glass is shown in Table 1.

Glass Formation Regions of Ge-Se-Te-Si3N4-CdS / HgTe Glass Ge30Se60Te10 (fixed) Si3N4 (wt%) CdS (wt%) HgTe (wt%) 0.1 to 1.0 1 to 5 1 to 7

In order to thin the electrode glass, the electrode glass was pulverized (S301), Ge-Se-Te-Si3N4-CdS / HgTe glass powder was used as a solute and an amine solvent to synthesize a coating solution (S302). After coating for 20 seconds in a spin coater (Spin Coater) to rotate at 2500rpm to dry at 200 ℃ to produce a thin film of Ge-Se-Te-Si3N4-CdS / HgTe (S303), and heat-treated (S304).

The prepared thin film is shown in FIGS. 4 and 5.

4 is a cross section of a Ge-Se-Te--Si3N4-CdS glass thin film, and FIG. 5 is a cross section of a Ge-Se-Te-Si3N4-HgTe glass thin film.

When the thin film is used as a heavy metal ion selective electrode, a modified surface layer is formed on the surface of the thin film by an oxidation-reduction reaction, and ion exchange occurs at this portion. This reaction occurs simultaneously on the inner and outer surfaces of the glass membrane, revealing the concentration difference between the common ions in the internal standard solution and the external test solution and the concentration gradient of holes produced by ion exchange. The movement of the charge carrier (Charge Carrier) is a current flow due to the diffusion due to the concentration gradient, the potential difference occurs inside and outside the glass film, the read value is pX (X = Cd, Hg).

(Example 1)

Ge-Se-Te-Si3N4-CdS thin films were prepared by spin coating, and Ge-Se-Te- in aqueous solution of Cd2 + was used to measure the response time in 1000 ppm Cd solution using the time when the potential difference reached equilibrium. The potential difference versus response time curve of the Si 3 N 4 -CdS glass electrode is shown in the graph of FIG. 6.

As shown in the curve of FIG. 6, the potential difference reached an equilibrium after about 20 seconds after the electrode was immersed in the Cd solution, and showed that the response time was shortened compared to the conventional commercialized material, and was stable up to about 200 ° C. Confirmed. In addition, as shown in (a) of FIG. 8, as a result of stability evaluation according to time of the electrode, it was shown that it is stable for more than 100 days.

(Example 2)

Ge-Se-Te-Si3N4-HgTe thin films were prepared by spin coating, and Ge-Se-Te-Si3N4 in Hg2 + aqueous solution was used to measure the response time in a 1000 ppm Hg solution using the time when the potential difference reached equilibrium. The potential difference versus response time curve of the -HgTe glass electrode is shown in FIG. 7. That is, the potential difference reached equilibrium after about 25 seconds after the electrode was immersed in the Hg solution, it was confirmed that it is stable up to about 200 ℃. In addition, as shown in (b) of FIG. 8, the stability evaluation result of the electrode was stable for more than 70 days.

According to the present invention, in the heavy metal ion detection sensor using a conventional polyvinyl chloride or epoxy electrode, the ion-selective electrode is added to the chalconitride glass reinforced with the network structure by adding Si3N4, and the method of manufacturing the thin film by chemical vapor deposition Metal ion-selective chalconitrile glass thin film replaced by spin coating method is more mechanically and chemically stable than conventional materials, and the spin coating method makes manufacturing process simpler, shortens response time, and increases the range of operating temperature. Due to this there is an effect that can be utilized as a next-generation heavy metal ion selective electrode material.

Claims (4)

A heavy metal ion selective glass electrode based on a chalcogenide glass having excellent ion and electrical conductivity, chemical stability, fast oxidation-reduction reaction in aqueous solution, and excellent sensitivity, The heavy metal ion selective glass electrode, A heavy metal ion-selective glass electrode, characterized in that a Ge-Se-Te-Si3N4-CdS / HgTe thin film is formed by doping CdS and HgTe in a chalconitrile mother glass prepared using Ge-Se-Te-Si3N4 as a starting material. In the manufacturing method of the heavy metal ion selective glass electrode for using chalcogenide glass which is excellent in ion and electrical conductivity, is chemically stable, and is quick in oxidation-reduction reaction in aqueous solution, and has excellent sensitivity as an ion selective electrode material, The manufacturing method of the heavy metal ion selective glass electrode, Preparing a mother glass by charging and sealing a quartz ampoule using Ge, Se, Te, and Si 3 N 4 as starting materials to melt and quench in a horizontal tube; Preparing a glass for an electrode by doping CdS / HgTe into the mother glass manufactured through the above step, charging and sealing a quartz ampoule, melting and quenching in a horizontal tube; The method of manufacturing a heavy metal ion-selective glass electrode, comprising the step of pulverizing the glass for electrode prepared in the above step, synthesizing a coating liquid, and manufacturing a thin film by spin coating and heat-treating the electrode glass. The method of claim 2, A method for producing a heavy metal ion selective glass electrode, characterized in that amine is used as the organic solvent used in the spin coating method. The method of claim 2, Optimum heat treatment of the thin film is a heavy metal ion selective glass electrode manufacturing method, characterized in that carried out at a temperature of 200 ℃.