APPLICATION PHOTOCATALYSIS FOR TREATMENT OF VOCS AND FORMALDEHYDE CONTAMINATIONS

APPLICATION DE PHOTOCATALYSE DESTINEE AU TRAITEMENT DE LA CONTAMINATION AUX COV ET AU FORMALDEHYDE

English Abstract

The photocatalytic solutions of the present invention comprise essentially of
about 0-10
weight % of Nano-Grade Metal Oxides, about 0-1 weight % of Thickening Agent,
about
0-3 weight % of Quaternary Ammonium Bromide, about 0-5 weight % of Organic
Acid
(1), about 0-5 weight % of Organic Acid (2), about 0-8 weight % of Alkylene
Glycol, and
about 80-95 Weight % of Distilled Water. These photocatalytic solutions can
effectively
eliminate the VOCs, including Formaldehyde, through the destruction or
transformation
of VOCs to innocuous end-products, i.e. CO2 and H2O.

Claims

Claims:
1. A photocatalytic solution composition for use in removal of harmful
organic
volatile chemical substances, bacteria and mould, comprising:
(a) about 0 to 10 Wt % of Nano-Grade Metal Oxides
(b) about 0 to 1 Wt % of Thickening Agent
(c) about 0 to 3 Wt % of Quaternary Ammonium Bromide
(d) about 0 to 5 Wt % of Organic Acid (1)
(e) about 0 to 5 Wt % of Organic Acid (2)
(f) about 0 to 8 Wt % of Alkylene Glycol
(g) about 89 to 95 Wt % of Distillated Water
2. The photocatalytic solution compositions according to claim 1(a),
wherein said
Nano-Grade Metal Oxide is Zinc Oxide or Titanium Dioxide or mixed Zinc Oxide
and Titanium Dioxide in 0 wt % to 100 wt %, respectively.
3. The photocatalytic solution compositions according to claim 1(b),
wherein said
Thickening Agent is Guar Gum or Bentonite or Corn Starch or Food Grade Flour
or a mixture thereof.
4. The photocatalytic solution composition according to claim 1(c),
wherein, said
Quaternary Ammonium Bromide is consisted of Cetyl Trimethyl Ammonium
Bromide.
5. The photocatalytic solution composition according to claim 1(d),
wherein, said
Organic Acid (1) is Acetic Acid or Formic Acid or a mixture thereof.
6. The photocatalytic solution composition according to claim 1(e),
wherein, said
Organic Acid (2) is Citric Acid or Oxalic Acid or a mixture thereof.
7. The photocatalytic solution composition according to claim 1(f),
wherein, said
Alkylene Glycol is selected from the group consisting of Ethylene Glycol, and
or
Propylene Glycol.
8. The photocatalytic solution composition according to claim 1(g),
wherein, said
Distillated Water is prepared by doubly distilled, or if such facility is not
available,
any filtered natural source of water or tap water will also do, nonetheless.

Description

Application Photocatalysis for Treatment of VOCs and Formaldehyde
Contaminations
Background of Invention:
1. Field of Invention
The present invention is related to the novel photocatalytic solutions, which
could effectively
eliminate the VOCs, including Formaldehyde. Volatile organic compounds (VOCs)
are the
major group of indoor air pollutants, which significantly impact indoor air
quality and
influence human health. Photocatalytic Oxidation is a cost-effective
technology for VOCs
removal, compared with adsorption, biofiltration, or thermal catalysis method.
Development
of active photocatalyst systems is crucial for the Photocatalytic Oxidation
reaction. Among a
large number of engineered nano metal oxides, TiO2 and ZnO (nano-particles)
are of
particular interest.
2. Description of Prior Art
In today's life, indoor air pollutions have drawn a global attention regarding
the
improvement of indoor air quality. Indoor air pollutants mainly include
Nitrogen Oxides
(NO), Carbon Oxides (CO and CO2), VOCs and Particulates. Among the pollutions,
VOCs
are prominent representative indoor pollutants of which, Acetone (C3H60), 1-
Butanol
.. (C411100), Butyraldehyde (C41180), m-Xylene (C81110) could be converted to
harmless CO2
and H20 through Heterogeneous Photocatalytic Oxidation as revealed by Peral
and 011is
[Journal of Catalysis, 136, 554-565, 1991].
Another VOC, i.e. Trichloroethylene (C2HC13) was studied by Jacoby, Blake and
Noble
[Journal of Catalysis, 157, 87-96, 1995], whom described the kinetics of the
oxidation of
Trichloroethylene in air via heterogeneous photocatalysis.
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Obee and Brown [Environmental Science and Technology, 29, 1223-1231, 1995]
reported
the effects of humidity and traces contaminant levels on the oxidation rates
of 1,3-Butadiene
(C4H6), Toluene (C6H5CH3), and Formaldehyde (CH20) by TiO2 Photocatalysis.
VOCs are known to have long term effects on humans and considered to be
carcinogenic,
.. mutagenic, or teratogenic, as reported by Tsoukleris, Maggos and Vassilakos
et al. [Catalyst
Today, 129, 96-101, 2007].
Moreover, Derwent, Jenkin and Saunders et al. [Atmospheric Environment, 37,
1983-1991,
2003] studied some VOCs emissions and reported that these emissions can
contribute to the
formation of urban smog and ozone, stratospheric ozone depletion and the
greenhouse effect.
With the increasing concerns on the indoor air quality, the degradation of
VOCs has easily
become the main point of research efforts in today's scientific world.
JPH09225322 discloses
compositions containing nano- TiO2 that could decompose environmental
pollutants in water
and air.
US20130156649A1 describes the construction of the "Purification Unit and
Deodoriding
Device", of which nano- TiO2 was deployed as the active ingredient.
TiO2 is the most popular photocatalyst currently employed due to the
hydrophilic
properties of TiO2 and its ability to degrade a wide range of inorganic and
organic compounds
under irradiation of UV or near UV-light. The development of new
photocatalysts appeared
therefore to be a necessity to push forward the current photocatalytic
performances. A lot of
.. researches are currently conducted to find out new materials and/or improve
the properties of
the current ones. This invention focuses on the enhancing strategies to boost
the
photocatalytic efficiency of the two most common photocatalysts, TiO2 and ZnO.
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Summary of the Invention
The present invention provides a photocatalytic solution composition for use
in
removal of harmful organic volatile chemical substances, bacteria and mould,
comprising:
(a) about 0 to 10 Wt % of Nano-Grade Metal Oxides
(b) about 0 to 1 Wt % of Thickening Agent
(c) about 0 to 3 Wt % of Quaternary Ammonium Bromide
(d) about 0 to 5 Wt % of Organic Acid (1)
(e) about 0 to 5 Wt % of Organic Acid (2)
(f) about 0 to 8 Wt % of Alkylene Glycol
(g) about 89 to 95 Wt % of De-ionized Water
The composition solution can be sprayed directly onto any cleaned surfaces,
which
boasts great self-cleaning power in the presence of sun light, known as
"Photocatalysis".
Photocatalysis is the acceleration of a photoreaction in the presence of a
catalyst. In catalyzed
photolysis, light is absorbed by an adsorbed substrate. The process,
photocatalytic activity
(PCA), depends on the ability of the catalyst to create electron-hole pairs,
which generate free
radicals (e.g. hydroxyl radicals: =OH) able to undergo secondary reactions.
Its practical
application was made possible by the discovery of water electrolysis by means
of the nano-
particles (Ti02/Zn0).
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Harmless
Co= 4.0)
Harmful 7
Light
Organio Poll utant
gad Ica
Pr*OtOCMPiot
(T )
aro)
+
0 electron
Moreover, Volatile Organic Compounds (VOCs), including Formaldehyde, are the
major pollutants in indoor air, which significantly impact indoor air quality
and thus
influencing human health. A long-term exposure to these VOCs will be
detrimental to human
health causing sick building syndrome (SBS). Photocatalytic oxidation of VOCs
is a cost-
effective technology for VOCs removal compared with adsorption, biofiltration,
or thermal
catalysis.
Researchers have developed a method for keeping walls and windows clean
without
human intervention. The key to these self-cleaning surfaces are
photocatalysts, substances
that mediate chemical reactions and are activated by light energy. When
organic matter
comes into contact with a photocatalyst, it is oxidized at an increased rate
and decomposes
into water and carbon dioxide. In layman's terms, the VOC contaminants come
into contact
with the Photocatalyst, they would be destroyed and turned to carbon dioxide
and water. This
property enables photocatalyst-coated walls and windows to break down any
organic dirt that
sticks to them.
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Description of the preferred Embodiment
The present invention is directed to photocatalytic solution compositions for
treatment
of VOCs and Formaldehyde contaminations. The characteristics of the inventive
composition
include its non-toxic nature, greater efficiency in terms of rate of
disrupting contaminants'
molecular structure, more rapid reaction toward sunlight, and improved safety
due to a lower
vapor pressure. .
The preferred Nano-Grade Metal Oxide (particle size between 10nm-200nm), which
is
white color powder. When dispersed totally in solution, it is colorless. The
photocatalytic
solution preferably comprise from about 0 wt % to about 10 wt % of nano-grade
Metal Oxide,
more preferably from about 1 wt % to 5 wt % of Metal Oxide.
The preferred Nano-Grade Metal Oxide is preferred to be Zinc Oxide, Titanium
Dioxide or mixed Zinc Oxide and Titanium Dioxide in 0 wt % to 100 wt %,
respectively.
The photocatalytic solution preferably comprise from about 0 wt % to about 1
wt % of
Thickening Agent. The Thickening Agent can be selected from Guar Gum,
Bentonite, Corn
Starch or Food Grade Flour. The preferred Thickening Agent is preferred to be
Guar Gum
from about 0.01 wt % to 0.5 wt % of Guar Gum.
The photocatalytic solution preferably comprise from about 0 wt % to about 3
wt % of
Quaternary Ammonium Bromide as surface active agent, is more preferably Cetyl
Trimethyl
Ammonium Bromide, which is a cationic surfactant with anti-bacteria function.
The preferred
Cetyl Trimethyl Ammonium Bromide is more preferred to be from about 0.1 wt %
to 1 wt %.
The preferred Organic Acid (1), which is transparent liquid. The
photocatalytic
. solution preferably comprise from about 0 wt % to about 5 wt % of Organic
Acid, more
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preferably from about 1 wt % to 5 wt %. The preferred Organic Acid is
preferred to be Acetic
Acid, Formic Acid or mixed Acetic Acid and Formic Acid in 0 wt % to 100 wt %,
respectively.
The preferred Organic Acid (2), which is white powder. The photocatalytic
solution
preferably comprise from about 0 wt % to about 5 wt % of Organic Acid, more
preferably
from about 1 wt % to 5 wt %. The preferred Organic Acid is preferred to be
Citric Acid,
Oxalic Acid or mixed Citric Acid and Oxalic Acid in 0 wt % to 100 wt %,
respectively.
The photocatalytic solution preferably comprise from about 0 wt % to about 8
wt % of
Alkylene Glycol with high affinity of hydroscopic property, is more preferably
Propylene
Glycol, which possesses water liking function. The preferred Propylene Glycol
is more
preferred to be from about 0.5 wt % to 3 wt %.
The photocatalytic solution of the present invention also comprises 89 wt % to
95 wt
% of Distilled Water as aqueous media, which forms nano-micelle with the metal
oxide, more
preferably from 90 wt % to 95 wt %.
All of the above inventive photocatalytic solution compositions are suitable
for the
removal of the airborne pollutants.
It is to be understood that the invention is not limited in its application to
the details of
the removal of airborne pollutants. The invention is capable of other
embodiments and of
being practiced and carried out in various ways. Also, it is to be understood,
that the
phraseology and terminology employed herein are for the purpose of description
and should
not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon
which this
disclose is based, may readily be utilized as a basis for designing other
chemical compositions,
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formulae and fuels for carrying out the several purposes of the present
invention. And the
abstract of the present invention is just an abstract, not intended to be
limiting as to the scope
of the invention in any way.
,
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