PREPARATION METHOD OF PHOTOLUMINESCENT PHOTOCATALYTIC BEADS FOR DECOMPOSITION OF HARMFUL SUBSTANCES AND REMOVAL OF VIRUSES, AND PHOTOCATALYST BEADS OBTAINED FROM THE METHOD

Abstract

Provided is a method of preparing photoluminescent photocatalyst beads for removing harmful substances or viruses present in air, soil, and water, and more particularly to a method of preparing photoluminescent photocatalyst beads that are efficient in decomposing and removing a mixture of hard-to-decompose organic contaminants and removing viruses by preparing a photoluminescent photocatalyst in the form of a bead, and photoluminescent photocatalyst beads obtained from the method.

Claims

1. A method of preparing photoluminescent photocatalyst beads for decomposition of harmful substances and removal of viruses, comprising: ball-milling a mixture of a phosphor, zeolite, an inorganic binder, and titanium dioxide for 6 to 10 hours; mixing 10 to 50 parts by weight of water with 100 parts by weight of the ball-milled mixture and kneading; preparing the kneaded product in a form of beads through a bead filling machine; drying the beads at 100 to 110° C. for 1 to 3 hours; immersing the dried beads in a SiO.sub.2 sol to coat the beads; subjecting the coated beads to a first heat treatment at 400 to 500° C. for 1 to 2 hours; primarily immersing the first heat-treated beads in a 10% sodium silicate solution; subjecting the beads, which have been primarily immersed, to a second heat treatment at 100 to 150° C. for 1 hour to 2 hours; secondarily immersing the second heat-treated beads in a 10% sodium silicate solution; subjecting the beads, which have been secondarily immersed, to a third heat treatment at 100 to 150° C. for 1 hour to 2 hours; immersing the third heat-treated beads in a TiO.sub.2 sol to coat the beads with TiO.sub.2; and subjecting the TiO.sub.2-coated beads to a fourth heat treatment at 400 to 500° C. for 1 to 2 hours.

2. The method of claim 1, wherein the phosphor is selected from the group consisting of CaAl.sub.2O.sub.4: Eu-based, SrAl.sub.2O.sub.4:Eu-based, BaAl.sub.2O.sub.4: Eu-based, ZnS: Cu-based, CaAl.sub.2O.sub.19: Eu-based, SrAl.sub.2O.sub.19: Eu-based, BaAl.sub.2O.sub.19: Eu-based, BaMgAl.sub.10O.sub.17: Eu-based, SrMgAAl.sub.10O.sub.17: Eu-based, and BaMg.sub.2Al.sub.10O.sub.17: Eu-based phosphors.

3. The method of claim 1, wherein the mixture in the ball milling step is composed of 30 to 50% by weight of a phosphor, 30 to 50% by weight of zeolite, 10 to 20% by weight of an inorganic binder, and 1 to 5% by weight of TiO.sub.2.

4. The method of claim 1, wherein the SiO.sub.2 sol coating solution is prepared by mixing tetraethyl orthosilicate(TEOS):ethanol:distilled water:nitric acid in a ratio of 2:13.5:11.5:0.3 parts by weight, mixing 0.8 parts by weight of polydimethylsiloxane (PDMS) based on 100 parts by weight of the mixture, stirring at 30° C. for 1 hour, and then aging for 24 hours.

5. The method of claim 1, wherein the TiO.sub.2 coating includes coating with a TiO2 sol formed by mixing titanium isopropoxide (TTIP):ethanol:nitric acid:distilled water in a ratio of 2:13.5:0.3:11.5 parts by weight and stirring at 30° C. for 1 hour.

6. Photoluminescent photocatalyst beads for decomposition of harmful substances and removal of viruses, prepared according to the method of claim 1.

Description

[DESCRIPTION OF DRAWINGS]

[0026] FIG. 1 is a flowchart schematically illustrating a method of preparing photoluminescent photocatalyst beads according to one embodiment of the present invention.

[0027] FIG. 2 is a photograph comparing the shapes of a general photocatalyst and photoluminescent photocatalyst beads prepared by the preparation method according to the present invention.

[0028] FIG. 3 is a graph showing the results of photolysis experiments using a general photocatalyst and photoluminescent photocatalyst beads according to the present invention.

[0029] FIG. 4 is a test report on the harmful gas removal efficiency of an air purifier manufactured using photoluminescent photocatalyst beads according to the present invention.

[MODES OF THE INVENTION]

[0030] Hereinafter, preferred embodiments of the present disclosure will be described in more detail. However, the following specific structure or functional descriptions are only illustrated for the purpose of explaining embodiments according to the concept of the present invention, embodiments according to the concept of the present invention can be implemented in various forms, and it should not be understood as being limited to the examples described herein.

EXAMPLE

[0031] Phosphor:zeolite:sodium alginate:sodium silicate:titanium dioxide were mixed in a wt% ratio of 37:37:8:17:1, and then were ball-milled for 6 hours. 20 kg of water was added to 100 kg of the ball-milled mixture and kneaded for 10 minutes, and the resulting mixture was prepared in the form of beads with a size of 5 mm in a bead filling machine.

[0032] The beads prepared as above were dried at 110° C. for 2 hours.

[0033] After coating the dried beads by immersing the dried beads in a SiO.sub.2 sol, a first heat treatment was performed at 400° C. for 2 hours.

[0034] The coated beads were primarily immersed in a 10% sodium silicate solution, subjected to a second heat treatment at 110° C. for 1 hour, secondarily immersed in a 10% sodium silicate solution, and then subjected to a third heat treatment at 110° C. for 1 hour.

[0035] The heat-treated beads were immersed in a TiO.sub.2 sol, coated with TiO.sub.2, and then heat-treated at 450° C. for 2 hours to obtain photoluminescent photocatalyst beads according to the present invention.

Comparative Example

[0036] A photocatalyst plate was prepared by coating titanium dioxide on a metal plate (SUS) and used in the experiment.

EXPERIMENTAL EXAMPLE

Photolysis Experiment

[0037] 1 drop of acetic acid was added to a 0.3 m.sup.3 chamber, diffused for 30 minutes, and followed by photolysis for 2 hours.

[0038] As shown in FIG. 3, it was found that a general photocatalyst according to the Comparative Example exhibited a photolysis effect of about 40% for an initial 30 minutes and a final photolysis effect of 50%.

[0039] In contrast, the photoluminescent photocatalyst prepared according to the present invention exhibited a photolysis effect of 85% for 30 minutes and a final photolysis effect of 95%.

[0040] As can be seen from the experimental results, it was confirmed that a photocatalytic effect of the photoluminescent photocatalyst prepared according to the present invention is about twice as high as that of the general photocatalyst.

[0041] Furthermore, FIG. 4 shows the result of testing a harmful gas removal rate of an air purifier using the photoluminescent photocatalyst prepared according to the present invention, and it was confirmed that the average removal rates of ammonia gas, acetaldehyde, acetic acid, formaldehyde, toluene, and the like are 95% or more.