Method of making UV lamp for air cleaning

The invention relates to a method for fabricating a UV lamp for treating waste gas and to a UV lamp for treating waste gases fabricated therefrom, which is designed and fabricated based on solgel coating techniques by coating a sol of photocatalytic materials comprising anatasse TiO.sub.2 as the main component, and/or other semi-conductive components such as WO.sub.3, ZnO, SnO.sub.2, or Fe.sub.2 O.sub.3, on a glass-fiber-cloth, and/or then impregnate this cloth with oxidation catalyst of precious metal such as Pd, Au, Pt or Ag, or transition metal oxide about Mo, Nb, B, Ce or Cr, and then wrap this cloth on a UV lamp. The invention relates also to a process for treating waste gases by using said UV lamp for treating waste gas through irradiating UV light therefrom on the surface of such photocatalytic materials to generate free electron and electron hole pairs which can decompose waste gases such as organic or inorganic pollutants in the air into unharmful gases.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a method for fabricating a UV lamp for treating 
waste gas and to a UV lamp for treating waste gases fabricated therefrom, 
which is designed and fabricated based on solgel coating techniques by 
coating a sol of photocatalytic materials on a glass-fiber-cloth, and/or 
then impregnate this cloth with oxidation catalysts and finally, wrap and 
fix this cloth on a UV lamp. The invention relates also to a process for 
treating waste gases by using said UV lamp for treating waste gas through 
irradiating UV light therefrom on the surface of such photocatalytic 
materials to generate free electron and electron hole pairs which can 
decompose waste gases such as organic or inorganic pollutants in the air 
into unharmful gases. 
2. Description of the Prior Art 
Solgel techniques have been emphasized today by technically advanced 
countries for several main reasons, namely, when developments of 
traditional chemical and physical technologies met bottlenecks, and in 
particular, when inorganic materials produced through traditional 
techniques can no longer satisfy requirements, especially, for thin film 
coating, materials having multiple components and special structures that 
can not coated by conventional physical and/or chemical method, as well as 
when coating those material on irregularly curve surfaces can not been 
achieved by conventional evaporating disposition techniques, the solgel 
technique, on the other hand, can easily generate a metal oxide film 
thereon, and at the same time, it is the characteristic feature of the 
solgel technique that the photocatalytical film obtained thereby has a 
porous crystallite structure required by the photocatalytical action. 
Therefore, solgel coating techniques become one of the most interesting 
techniques for research and development in the latter part of the 
twentieth century. 
Recently, preparation of catalysts by solgel techniques also received 
emphasis by chemical industries, and in particular, photocatalytic 
techniques is the most important one, including the early developed 
photocatalytic powders for treating waste water, such as, for example, 
Robat A. Clyde, U.S. Pat. No. 4,446,236; Robat E. Hetrick, Ford Motor 
Company, U.S. Pat. No. 4,544,470; Yashiaki Harada et al., Osaka Gas 
Company, U.S. Pat. No. 4,699,720; Tomoji Kawai, et al., Nomura Micro 
Science Co., U.S. Pat. No. 4,863,608; David G. Ritchie, U.S. Pat. No. 
5,069,885; Gerald Cooper, et al., Photo Catalytics Inc., U.S. Pat. Nos. 
5,116,582; 5,118,422; 5,174,877; and 5,294,315; Adam Heller, et al., Board 
of Regents, The University of Texas System, U.S. Pat. No. 5,256,616; Ali 
Safarzedeh-Amiri, Cryptonics Corporation, U.S. Pat. No. 5,266,214; Fausto 
Miano & Borgarello, Eniricerche S.p.a., U.S. Pat. No. 5,275,741; Nancy S. 
Foster et al., Regents of the University of Colorado, U.S. Pat. No. 
5,332,508; Ivan Wlassics et al., Ausimont S.p.a., U.S. Pat. No. 5,382,337; 
Paul C. Melanson & James A. Valdez, Anatol Corporation, U.S. Pat. No. 
5,395,522; Henry G. Peebles III et al., American Energy Technology, Inc., 
U.S. Pat. No. 5,449,466; Brain E. Butters & Anthony L. Powell, Purific 
Environmental Technologies, Inc., U.S. Pat. Nos. 5,462,674; 5,554,300; and 
5,589,078; Yin Zhang, et al., Board of Control of Michigan Technology 
University, U.S. Pat. No. 5,501,801; Clovis A. Linkous, University of 
Central Florida, U.S. Pat. No. 5,518,992; and Eiji Normura & Tokuo Suita, 
Ishihara Sanyo Kaisha Ltd., U.S. Pat. No. 5,541,096. 
The above-mentioned U.S. patents relate chiefly to water treatments, which 
in the case of granular catalysts, a filtration recovering apparatus is 
invariably used, and it is of the most importance that such photocatalysis 
needs sufficient dissolved oxygen in water, otherwise, an aerating 
operation must carry out for supplying oxygen required by the 
photocatalytic degradation. 
Since then, photocatalysts were used also for treating waste gases, such as 
those described in, for example, Gregory B. Roupp & Lynette A. Dibble, 
Arizona State University, U.S. Pat. No. 5,045,288; Jeffrey g. Sczechowski 
et al., The University of Colorado, U.S. Pat. No. 5,439,652; William A. 
Jacoby & Danial M. Blake, U.S. Pat. No. 5,449,443; Zhenyyu Zhang & James 
R. Gehlner, Inrad, U.S. Pat. No. 5,468,699; and Franz D. Oeste, Olga 
Dietrich Neeleye, U.S. Pat. No. 5,480,524. 
The above-mentioned patens relate originally to treatment of waste gases, 
and basically, were carried out in a closer reactor, and therefore, 
utilization or operation of granular catalysts or catalysts coating 
granules usually needed, in general, complicate equipments. 
The above-described disadvantages made the prior art photocatalysts 
difficult to apply on polluted air treating in our living environment, and 
among them, the only one waste water and/or waste gases disposal 
photocatalytic reactor comprising a UV lamp wrapped with photocatalysts 
coated film having fibers as supports thereof was the one described in 
Michael K. Robertson & Robert G. Henderson, Nutech Energy Systems Inc., 
U.S. Pat. No. 4,982,712. As above mentioned, such reactor was a closed 
type one such that counter flowing of gases must be forced by a blower 
which made such reaction system being inconveniently practice in our 
living environment. 
As for UV lamp for treating waste gases, it is generally based on the 
sustained oxidative degradation against organic and/or inorganic hazardous 
materials in the air by a photocatalytic reaction to render them into 
nonharmful substances such as water or carbon dioxide. Since 
photocatalytic reaction took place on the catalyst through UV irradiating 
on hazardous waste gases and oxygen, it is inactive in case that UV light 
can not reach the catalyst. Accordingly, only the catalyst in the 
extremely thin top layer (less than one micron) that received UV light 
becomes active under such conditions. Therefore, in practice, it is used 
to employ a film coating of photocatalyst on carry substrate materials 
which are transmittable by UV or light to prepare a photocatalyst film. 
Photocatalytic action can be effected only in case of direct UV irradiation 
on coating, while it is inactive in case of backside irradiating. The 
reason therein relates to the fact that electron hole pairs generated 
during UV irradiating on the surface of photocatalyst will combine in 
extremely short time period (microseconds) and release thermal energy 
before reacting with oxygen and/or materials to be reacted. 
Nevertheless, a photoelectric-chemical catalyst having an electroconductive 
layer incorporated in the coating film structure can transfer electron 
generated during UV irradiating via the conductor therein to the positive 
electrode, such that the electron hole can be retained and the persisting 
time period of reactive positions can be postponed and thereby improves 
the efficiency of UV irradiation. However, such coating film is not easy 
to fabricate and practice. Consequently, it is essential for 
photocatalytical reaction to take place in simultaneous presence of 
oxygen, moisture, reactants and catalysts as well as in combination with 
UV irradiation to give rise the oxidative degradation. 
Since the effective thickness of photocatalysts is extremely small, it is 
sufficient for a layer of photocatalytical material having a thickness of 
less than 1 micron to be deposited on UV transmittable substrate by a 
solgel coating technique. Because photocatalytical materials are in 
general metal oxides, it is conventional to use vacuum deposition, redox 
plating, and aqueous precipitation/adsorption coating techniques to form a 
thin film. Among them, the vacuum deposition technique is usually employed 
for depositing on the surface of a flat structure, which can not meet the 
practical requirement in this field. Furthermore, since vacuum deposition 
is not capable of obtaining a porous structure of catalysts and a 
crystalline structure having photocatalytical action, it becomes useless 
therefor. The aqueous precipitation/adsorption coating technique consists 
of precipitating a photocatalytical metal oxide on the surface of a 
substrate, however, because the bonding strength between the catalyst thus 
adsorbed and the surface of the substrate is generally not strong enough, 
the coating peels easily and is not durable. As for the redox plating, 
titanium metal or alloy thereof has been used to form a titanium dioxide 
thin film under oxidation condition at high temperature, however, since 
the substrate is an opaque metal and the surface area of the catalyst film 
thus obtained is insufficient, the photocatalytical efficiency is poor to 
be practical. 
As sated previously, since the solgel coating technique can generate easily 
a coating film on an irregular surface structure as well as can produce a 
porous crystallite structure required by the photocatalytical action, and 
also from the view of the inherent feature of the photocatalytical 
reaction, the present inventors adopt the solgel coating technique for 
fabricating the UV lamp for treating waste gases according to the 
invention. 
As for the solgel coating technique, in general, a metal alkoxide such as 
Ti(OR).sub.4, wherein R is a hydrocarbyl group, CnH.sub.2 n.sub.+1, where 
n=1.about.5, and is, for example, methyl, ethyl, n-propyl, isopropyl, 
n-butyl, t-butyl, sec-butyl, pentyl and the like; is used as the main 
component in admixture with organic and/or inorganic salts of other metals 
such as W, Zn, Sn, and Fe and undergoes hydrolytic condensation in an 
alcohol solvent to form an organic metal polymer which is dissolved in 
that alcohol solution as a sol. Amounts of alkoxide, water, additives and 
solvent can be adjusted depending to the requirement of coating to form 
the desired film. 
As the substrate used in the solgel coating technique, glass fiber woven 
cloth can provides an increased surface area of photocatalysts and can 
allow waster gases in the air diffuse readily in the photocatalytic active 
sites. The glass fiber woven cloth can be the one conventionally used in 
production of the printing circuit board, which, in general, has a fiber 
diameter of 10.about.100.mu., fiber number of 1.about.10, and porosity of 
100.about.1000 mesh. The glass fiber woven cloth can be reinforced with a 
silane. In addition to the glass fiber, other materials such as quartz, 
ceramics or metal can be used as the substrate. 
Then, the glass fiber cloth can be impregnated batchwise or continuously 
with the photocatalyst sol by a roller, wherein, through controlling the 
drawing speed of the cloth and the humidity and temperature in the air, an 
uniform layer (0.1.about.1.0.mu.) of photocatalyst coating can be applied 
on the surface of the glass fiber cloth. The coated fiber cloth is 
undergone a hydrolysis in the air for 1.about.10 minutes, baked at a 
temperature of 100.about.200.degree. C. for 10.about.30 minutes, sintered 
at high temperature of 400.about.600.degree. C. for 10.about.120 minutes 
and thereafter, cooled for 10.about.120 minutes to a temperature below 
200.degree. C. to produce a photocatalyst-coated glass fiber cloth. 
In the production of the above-described photocatalyst-coated glass fiber 
cloth, in order to improve the efficiently of treating waste gases, it can 
be soaked with a aqueous solution containing metal salts having oxidative 
catalytic action. Such metal salts include precious metal such as 
inorganic salts of Pd, Pt, Au and Ag or inorganic salts of transition 
metal such as Mo, Nb, V, Ce or Cr. The glass fiber cloth is ready for use 
after being soaked with oxidative catalyst after dried. 
For use of the above-said photocatalyst and/or oxidative catalyst-coated 
glass fiber cloth in production of the UV lamp for treating waste gases, 
they can be tailored into a size depending on the length or size of the UV 
lamp and the number of wrapping layer required. In general, the number of 
layer is to achieve an UV blocking of above 99%, and normally, is 
2.about.3 layers. After wrapping around the UV lamp, it is fixed by UV 
resistant glue, or seamed by laser sintering. 
Suitable UV lamp is the common UV lamp, including those having wavelength 
of 254, 312 or 365 nm. Among them, UV lamps having wavelength of 254 and 
312 nm should employ SiO.sub.2 quartz and thus have high production costs, 
whereas the one having wavelength of 365 nm can be produced with soda lime 
glass tubes and has a low cost. Depending on the type of waste gases 
treatments, a UV lamp of 254 nm can be used for the case requiring higher 
energy for degrading waste gases and those of 365 nm can be used for the 
photocatalytic degradation of common waste gases. The UV of 365 nm is 
known as mosquito-capturing lamp, whereas the UV lamp of 254 nm is known 
as sterilizing lamp. Therefore, if the 365 nm UV lamp is wrapped with 
topical or a single layer of a photocatalyst-coated glass fiber cloth, it 
can function both as waste gas treating and mosquito-capturing; whereas 
the 254 nm UV lamp is wrapped with topical or a single layer of a 
photocatalyst-coated glass fiber cloth, it can function both as waste gas 
treating and sterilization. 
SUMMARY OF THE INVENTION 
Accordingly, in one aspect, the invention provides a process for coating 
photocatalyst on a glass fiber woven cloth, which comprising (1) 
formulating a photocatalyst coating-forming sol; (2) dip coating a glass 
fiber cloth with a photocatalyst sol; (3) drying and sintering into a 
coating having photocatalytic function; (4) impregnating said 
photocatalyst-coated glass fiber cloth with a solution of an oxidation 
catalyst; and (5) drying again to form a photocatalyst-coated glass fiber 
cloth. 
In another aspect, the invention provides a process for fabricating a UV 
lamp for treating waste gas, which is designed and fabricated through 
solgel techniques by coating photocatalytic materials on a quartz-or 
glass-fiber-cloth, sintering this photocatalytic material-coated fiber 
cloth at high temperature into a structure having photocatalytic action, 
and then wrapping this cloth on a UV lamp. 
In still another aspect, the invention provides a UV lamp for treating 
waste gases, which is fabricated by the above-described process. 
In yet another aspect, the invention provides a method for treating waste 
gases in the air by using the above-said UV lamp through irradiating UV 
light on the surface of such photocatalytic materials to generate free 
electron and electron hole pairs which can decompose waste gases in the 
air into harmless products.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As stated above, in one aspect, the invention provides a process for 
coating photocatalyst on a glass fiber woven cloth, which comprising (1) 
formulating a photocatalyst coating-forming sol; (2) dip coating a glass 
fiber cloth with a photocatalyst sol; (3) drying and sintering into a 
coating having photocatalytic function; (4) impregnating said 
photocatalyst-coated glass fiber cloth with a solution of an oxidation 
catalyst; and (5) drying again to form a photocatalyst-coated glass fiber 
cloth. 
The photocatalyst sol used in the above-said process for coating 
photocatalyst on a glass fiber woven cloth contains as the main component 
a metal alkoxide such as Ti(OR).sub.4, wherein R is a hydrocarbyl group, 
CnH.sub.2 n.sub.+1, where n=1.about.5, and is, for example, methyl, ethyl, 
n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, pentyl and the like; in 
a solvent such as alcohols, for example, ethanol, isopropanol, butanol, 
pentanol and the like. Amount of water added should be controlled to a 
H.sub.2 O/Ti(OR).sub.4 mol ratio of 0.5.about.2. Suitable amount of 
organic acid such as formic acid, acetic acid, propionic acid and the 
like, can be added as modifier and HCl or hNO.sub.3 is used to adjust pH 
thereof in a range of 1.0.about.3.0. Then, after reacting under stirring 
and heating, a TiO.sub.2 sol can be obtained. The concentration of the 
TiO.sub.2 sol can be adjusted with alcohol solvent to a suitable range of 
1.about.10 wt %. 
The thus-formed TiO.sub.2 sol can be incorporated with other photocatalytic 
components including WO.sub.3, ZnO, SnO.sub.2, and Fe.sub.2 O.sub.3 which 
can be added as organic and/or inorganic salts thereof. The inorganic 
salts thereof can be halides and nitrates, whereas the organic salts can 
be acetates and acetoacetonate provided that they are soluble in the 
alcohol solvent. The alcohol solution obtained after dissolving completely 
can be evaporated to remove water and then redissolved by adding alcohol 
solvent to form a precursor alcohol solution of WO.sub.3, ZnO, SnO.sub.2, 
and Fe.sub.2 O.sub.3. Addition of the MOx precursor alcohol solution is 
desired amount to lead to a weight ratio of MOx/TiO.sub.2 =1.about.100% 
results in a photocatalyst coating forming sol. 
The thus-formed photocatalyst coating-forming sol can be used then to apply 
on a substrate such as glass, ceramics, carbonaceous materials or metal, 
which, preferably, are transparent and in fibrous shape. In one embodiment 
of the invention, the substrate is a fiber or a fiber bundle. The solgel 
coating technique can apply directly on the fiber or fiber bundle, while 
it can apply after weaving of the fiber. Since, after solgel coating and 
sintering, the fiber and fiber bundle can be bonded directly by an 
adhesive into an useful nonwoven, otherwise, they might be damaged by 
weaving machine during weaving after solgel coating. Therefore, it is 
desirable to solgel coating on fiber woven cloth and sintered to fabricate 
the desired photocatalyst-coated fiber cloth. 
The drying and sintering in the solgel coating process according to the 
invention can be carried out conventionally, such as, impregnating the 
glass fiber cloth batchwise or continuously with the photocatalyst sol by 
a roller, wherein, through controlling the drawing speed of the cloth and 
the humidity and temperature in the air, an uniform layer 
(0.1.about.10.mu.) of photocatalyst coating can be applied on the surface 
of the glass fiber cloth. The coated fiber cloth is undergone a hydrolysis 
in the air for 1.about.10 minutes, baked at a temperature of 
100.about.200.degree. C. for 10.about.30 minutes, sintered at high 
temperature of 400.about.600.degree. C. for 10.about.120 minutes and 
thereafter, cooled for 10.about.120 minutes to a temperature below 
200.degree. C. to produce a photocatalyst-coated fiber cloth. 
In order to improve the capacity and efficiency of photocatalyst coating on 
treating waste gases, such as those containing organic substances having 
halogen, nitrogen, phosphorus and sulfur elements, the photocatalyst must 
be incorporated with oxidation catalysts. Suitable oxidation catalysts can 
be those commonly used, including such as, precious metal type and 
transition metal type. The precious metal type is usually presented as 
elemental state, such as, for example, Pd, Pr, Au or Ag, whereas the 
transition metal type is presented as metal oxides such as, for example, 
MoO.sub.3, Nb.sub.2 O.sub.5, V.sub.2 O.sub.5, CeO.sub.2 or Cr.sub.2 
O.sub.3. The amount of such oxidation catalysts in the photocatalyst is in 
a range of 018 10.0 wt %. Because such oxidation catalyst itself exhibits 
an ability of oxidizing waste gases in the air as well as can capture free 
electrons, electron hole pairs or active radicals generated from the 
action of the free electrons and electron hole pairs on O.sub.2 and 
H.sub.2 O, such as, .OH, H.sup.+, .O.sub.2.sup.-, HO.sub.2., OH.sup.- and 
the like which are released subsequently for oxidative degrading waste 
gases as they approached, such that the existing time period of electron 
hole and free electrons can be sustained and thereby improve the capacity 
and efficiency of the photocatalysts. 
According to the process of the invention, the addition of oxidation 
catalyst is carried out, after solgel coating a photocatalyst on the fiber 
woven cloth, by impregnating the cloth with a solution of oxidation 
catalytic metal salt. Since the fiber woven cloth itself has a meso-pores 
and the photocatalyst coating has many micro pores, when the 
photocatalyst-coated fiber cloth is dipped in the solution of metal salts, 
the oxidation catalytic metal salts will be adsorbed in the meso pores 
within the fiber cloth and/or be absorbed in the micro-pores within the 
photocatalyst coating, which, after evaporating the solvent, has many fine 
metal salts remained on the fiber cloth and thus accomplishes the process 
of incorporation of oxidation catalysts in the photocatalyst-coated fiber 
cloth. 
under irradiation of UV light, this layer of photocatalyst coating will 
generate free electron hole pairs. Oxygen and water on the surface of the 
catalyst will receive such electron hole pairs and become in an metastable 
state having oxidizing ability. When these ions in a metastable state 
having oxidizing ability encounter the organic or inorganic gases in the 
air, a chemical binding and degradation reaction will take place 
immediately. Under constantly supplying of those ions, the hazardous waste 
gases in the air will be degraded into unharmful gases which consist 
mainly of carbon dioxide and water. This photocatalytic reaction mechanism 
can be illustrated as follow: 
##EQU1## 
The above-mentioned reaction equations can be balanced into 
(1).times.3+(2).times.2+(3).times.3+(4).times.2+(5)+(6)+(7)+(8).times.4=(9 
). From equation (9), by way of example, when waste gas (A) is reacted 
firstly with .OH, 4 moles of waste gas require 2 moles of water and one 
mole of oxygen. Thus, this indicates that photocatalytical reaction needs 
absolutely both of water and oxygen. This conclusion is supported by the 
fact that, in the case of photocatalytic hydrolysis of organic materials 
in water, the reaction efficiency in the aqueous solution lack of 
dissolved oxygen is poor, and likewise, the reaction efficiency in air 
lack of moisture is also poor. Unless, subsequent to the photocatalytic 
degradation of waste gases in air, the product contains water or 
substances that can react with h.sup.+ in a manner analogous to water and 
thereby forms .OH and H.sup.+, the reaction mechanism can proceed 
continuously. 
In another aspect, the invention provides a process for fabricating UV lamp 
for treating waste gases which, as described above, is designed and 
fabricated through solgel techniques by coating photocatalytic materials 
on a quartz-or glass-fiber-cloth, sintering this photocatalytic 
material-coated fiber cloth at high temperature into a structure having 
photocatalytic action, and then wrapping this cloth on a UV lamp. 
In order to improve the efficacy of the UV lamp, and to not allow the UV 
and visible light generated by the UV lamp being absorbed by opaque 
materials such that the function of treating waste gases can not be 
provided, in one embodiment of the invention, quartz or glass fiber 
materials are used as the substrate. Among them, quartz lass is a material 
consisting of SiO.sub.2 which is transmittable by the UV light having 
wavelength of 254 nm, 312 nm and 365 nm derived from the UV lamp, while 
common glass is transmittable only by UV light of 365 nm. If the 
activation energy for degrading waste gases is high, it is preferably to 
adopt UV lamps of 254 nm or 312 nm in conjunction with quartz glass fiber 
woven cloth as the supporting substrate of photocatalysts. With respect to 
the common organic waste gases, a UV lamp of 365 nm wavelength is 
sufficiently used in combination with common glass fiber woven cloth as 
the substrate. Thus, when the UV lamp illuminates on the 
photocatalyst-coated glass fiber woven cloth, a portion of the light will 
be absorbed, a portion reflected and a portion be transmitted, wherein 
reflected and transmitted portions can be absorbed subsequently by the 
photocatalyst coating till completely absorbed for proceeding of 
photocatalytical degradation of waste gases. 
Now, referring to FIGS. 1A-C, the structure of the photocatalyst thin 
coating on the surface of the photocatalyst-coated quartz or common glass 
fiber prepared by the above-described solgel coating process according to 
the invention and impregnated with oxidation catalysts will be illustrated 
as follow: if a single glass fiber &lt;1&gt; was photocatalyst-coated &lt;2&gt;, as 
shown in FIG. 1(A), there are tine interstitial pathway &lt;6&gt; surrounding 
the anatase TiO.sub.2 crystal &lt;7&gt; within the coating, as shown in FIG. 
1(B), and a plurality of fine oxidation catalysts are adsorbed on the 
surface of the coating as well as in the internal interstitial pathway, as 
shown in FIG. 1(C). 
If a bundle consisting a number of glass fibers &lt;5&gt; has been 
photocatalyst-coated &lt;2&gt;, as shown in FIG. 2(C), similarly, there are 
likewise anatase TiO.sub.2 crystals &lt;7&gt; and tine interstitial pathways &lt;6&gt; 
within the structure of the photocatalyst coating, and there are a 
plurality of fine oxidation catalysts &lt;3&gt; absorbed on the surface of the 
coating as well as in the inner interstitial pathways. If a glass fiber 
woven cloth &lt;4&gt; has been photocatalyst-coated &lt;2&gt;, as shown in FIG. 2(A), 
a photocatalyst-coated glass fiber woven cloth &lt;41&gt; is obtained, as shown 
in FIG. 2(B), there are again anatase TiO.sub.2 crystals &lt;7&gt; and tine 
interstitial pathways &lt;6&gt; within the structure of the photocatalyst 
coating, and there are a plurality of fine oxidation catalysts &lt;3&gt; 
absorbed on the surface of the coating as well as in the inner 
interstitial pathways. 
Now, referred to FIGS. 3A-C, as one aspect of the invention, the 
fabrication of the UV lamp for treating waste gases according to the 
invention will be explained below. The UV lamp for treating waste gases 
according to the invention is fabricated by wrapping around a UV lamp tube 
with a photocatalyst-coated glass fiber woven cloth in a manner as winding 
type, covering box type or sleeve type, as shown in FIG. 3. In case of 
using linear UV lamp tube &lt;11&gt;, one or two round of a photocatalyst-coated 
glass fiber cloth &lt;41&gt; are wound plainly around the tube and fixed on the 
glass tube by applying on both end and the edge with adhesives such as UV 
light resistant silicone type adhesives or glass cement, such as shown in 
FIG. 3(A). 
In the case of circular UV lamp tube &lt;12&gt;, the photocatalyst-coated glass 
fiber cloth can be tailored into a covering box &lt;42&gt; and cover the box on 
the circular UV lamp tube, as shown in FIG. 3(B). While in the case of 
U-shaped UV lamp tube &lt;13&gt;, the photocatalyst-coated glass fiber cloth can 
be tailored into a sleeve &lt;43&gt; and slip the sleeve &lt;43&gt; on the U-shaped UV 
lamp tube, as shown in FIG. 3(C). 
Furthermore, in order to retain the original function of the UV lamp, the 
UV lamp tube can be wrapped with the photocatalyst-coated glass fiber 
cloth on a part thereof, such as in a manner of &lt;412&gt; shown in FIG. 4(C), 
such that, for example, the 365 nm UV lamp which uses soda lime glass tube 
&lt;112&gt; can thereby have both functions of waste gas treatment and 
mosquito-capturing, while the partly wrapped 254 nm or 312 nm UV lamp 
which use quartz glass tube &lt;111&gt; can thereby have both functions of waste 
gases treatment and sterilization. 
The linear UV lamp can be wrapped on whole tube with a photocatalyst-coated 
glass fiber cloth in a manner as &lt;411&gt; shown in FIG. 4(B) with its 
cross-section view shown in FIG. 4(A). As to the constructure of that UV 
lamp, a quartz glass tube &lt;111&gt; or soda lime glass tube &lt;112&gt; is vacuum 
sealed at both ends. The heating filaments &lt;113&gt; therein are filled with 
minor amount of mercury and are connected with external heating pins 
&lt;114&gt;. Next, the tube is sealed by cementing with tube bases &lt;115&gt; at both 
ends. Finally, the photocatalyst-coated glass fiber cloth &lt;41&gt; is wound 
around and fixed on the UV lamp by a two-sided adhesive film &lt;116&gt; and 
then sealed the edge by a quick drying UV adhesive &lt;117&gt;, as shown in FIG. 
5(A), and thereby accomplishes the fabrication of the UV lamp for treating 
waste gases according to the invention. 
In the fabrication of the UV lamp for treating waste gases according to the 
invention, the circular UV lamp tube &lt;12&gt; is wrapped with 
photocatalyst-coated glass fiber cloth box &lt;42&gt; and the U-shaped UV lamp 
tube &lt;13&gt; is wrapped with a photocatalyst-coated glass fiber cloth sleeve 
&lt;43&gt;, wherein these photocatalyst-coated glass fiber cloth box &lt;42&gt; or 
sleeve &lt;43&gt; can be made separately, and, when they are used, they can be 
simply placed on the UV lamp tube in a manner as described above to 
function. 
As described above, the UV lamp for treating waste gases according to the 
invention is constructed by wrapping a photocatalyst-coated glass fiber 
woven cloth around a UV lamp tube such that, when the UV lamp is turned on 
in the air, a function of waste gases treatment occurs accordingly. As 
such, no mater whether the photocatalyst-coated glass fiber woven cloth is 
used to warp around a linear UV lamp &lt;11&gt;, a circular UV lamp &lt;12&gt; or a 
U-shaped UV lamp &lt;13&gt; tube, such function of treating waste gases always 
requires three conditions as following: (1) when turned on, UV lights of 
245 nm/312 nm or 365 nm emitted by the UV lamp will transmit through the 
glass tube and illuminate on the photocatalyst coating; (2) there are 
moisture and photocatyltically degradable waste gases in the air, which 
can diffuse through the large interstitial pathway within the coated glass 
fiber woven cloth to the photocatalyst coating illuminated by the UV 
light; and (3) unharmful gaseous products generated by photocatyltically 
degrading waste gases in the air and the air itself can back diffusing 
through the large intersitial pathway within the coated glass fiber woven 
cloth into the air. 
Now, as a yet another aspect of the invention, a process for treating waste 
gases according to the invention will be described below. In the process 
for treating waste gases according to the invention, the above-described 
UV lamp for treating waste gases is used. As the UV lamp for treating 
waste gases is wrapped with a photocatalyst-coated glass fiber woven 
cloth, the air &lt;21&gt; that contains organic or inorganic hazardous waste 
gases &lt;22&gt; normally contains also moisture &lt;23&gt; and carbon dioxide &lt;24&gt;, 
as illustrated in FIG. 5(A), which can pass from outside of the coated 
glass fiber woven cloth &lt;41&gt; into the interstitial space between the 
coated glass fiber cloth and the lamp tube by diffusing through the large 
interstitial pathway, whereupon, as the UV light emitted by the UV lamp 
illuminates on the photocatalyst &lt;2&gt;, electron hole pairs generated will 
combine with O.sub.2 and H.sub.2 O in the air to produce .OH free radical 
which then undergoes a oxidative degradation reaction with such hazardous 
waste gas &lt;22&gt; in the air according to the reaction equations (1) to (8) 
and the balanced reaction equation (9). The reaction products comprise 
H.sub.2 O &lt;23&gt;, CO.sub.2 &lt;24&gt; and other gases &lt;25&gt;, which, in combination 
with some O.sub.2 consumed residual air &lt;21'&gt;, unreacted waste gases 
&lt;22'&gt;, total moisture &lt;23'&gt; and total CO.sub.2 &lt;.gtoreq.'&gt;, discharge out 
of the coated glass fiber cloth &lt;41&gt; by back diffusing through the large 
interstitial pathway within said coated glass fiber woven cloth as shown 
in FIG. 5(B), while the change of reactants and products occurred upon UV 
illuminating the photocatalyst coating &lt;2&gt; on the glass fiber yarn bundle 
&lt;5&gt; is illustrated in FIG. 5(C). 
In one embodiment, the process for treating waste gases according to the 
invention comprises a open type of use of the UV lamp according to the 
invention, which, based on the fitting with surrounding facilities, can 
comprise nature convection and forced convection types, while, based on 
the manner of installation, can comprise horizontal and perpendicular 
installation types, that is, in such open types, it is unnecessary that 
the UV lamp for treating waste gases has to be in a closed container and 
the input of gases to be treated in the container and the output of 
gaseous products from the container must be conducted by a blower. It need 
simply install the UV lamp for treating waste gases, whereby, since, when 
the UV lamp is turned on, a heat energy from the heating filaments on both 
ends can transfer to the lamp tube, and, in the course of conversion of 
electric energy into UV light, heat energy generated from consumption of 
part of energy thereof can transfer also to the lamp tube, so that some 
definite heat energy will radiates from the lamp tube, and thereby 
provides energy required for nature convecting and diffusing the air. 
In one embodiment, the UV lamp for treating waste gases is hanged 
horizontally, the nature convection of air forces the air &lt;21&gt; beneath the 
UV lamp to flow upwardly and part of them diffuse into the gap between the 
photocatalyst-coated glass fiber woven cloth &lt;41&gt; and the UV lamp tube, 
where, after oxidative degradation by the action of the photocatalyst 
coating and the UV light, diffuse away the photocatalysts-coated glass 
fiber cloth &lt;41&gt;, while unreacted gases diffuses upwardly and outwardly 
along the gap, and finally, air &lt;21'&gt; in admixture with H.sub.2 O &lt;23'&gt;, 
CO.sub.2 &lt;24'&gt;, residual waste gases &lt;2'&gt; and gaseous reaction products 
&lt;25&gt; will diffuse upwardly and convects spontaneously out of the UV lamp; 
meanwhile, gases in the entire space will be continuously treated through 
gas diffusion and nature convection and by the action of the UV lamp for 
treating waste gases according to the invention, as illustrated in FIG. 
6(A). 
In another embodiment, the UV lamp for treating waste gases according to 
the invention is hanged perpendicularly, as shown in FIG. 6(C), where, the 
diffusion and spontaneous convection of the air, basically, are similar to 
those occurred in the horizontal installation. However, due to 
perpendicular hanging, the nature convection is stronger and the effect of 
gas diffusion is also stronger, and thereby provides better treating 
capability for waste gas. In yet another embodiment, an out sleeve &lt;8&gt; is 
provided around the UV lamp and results in better effect as illustrated in 
FIG. 6(B). Such outer sleeve is made of transparent material and must have 
an inner diameter larger than that of the UV lamp, for example, an inner 
diameter twice larger that the outer diameter of the UV lamp, while, has a 
length comparable to that of the UV lamp. 
In still another embodiment, in order to arrange a forced air convection, 
the UV lamp for treating waste gases can be installed in an air flowing 
space or a conduct, such as, for example, at the outlet of an air 
conditioner, within the air conduct of an air conditioner, on the base of 
ventilator in a bathroom, and in a sewer, whereby, the efficiency of waste 
gas treatment can be improved by means of external forced air convection, 
as illustrated in FIG. 7(A)/(B). 
In summary, the UV lamp for treating waste gases according to the invention 
can be installed in a open status, such as, simply replacing the common 
sunlight lamp tube with the UV lamp of the invention, whereby, when the 
lamp is turned on, the hazardous waste gases in air can be degraded into 
unharmful gases. Moreover, the UV lamp for treating waste gases according 
to the invention can be designed and tailor-made with respect to the 
requirements of various application situations, such as, air conditioning 
conduct in buildings, ventilation in family bathroom, refrigerator, food 
and dish store oven and air conditioner. Furthermore, the UV lamp of the 
invention can be designed and fabricated to have both the original 
function thereof such as mosquito-capturing and sterilization and the 
function of treating waste gases. In addition, the UV lamp for treating 
waste gases according to the invention can be used whole day, especially, 
at night and in dark room, where, since light source of a UV lamp tube do 
not emit just UV light but includes some bluish visible light also, such 
that it not only can be used as a low illumination lamp at night, but also 
can treat waste gases in air to keep the air clean. 
Many changes and modifications in the above described embodiments of the 
invention can, of course, be carried out without departing from the scope 
thereof. Accordingly, to promote the progress in science and the useful 
arts, the invention is disclosed and is intended to be limited not only by 
the scope of the appended claims.