PROCEDE ET DISPOSITIF D'OXYDATION PHOTOCATALYTIQUE D'ESPECES CHIMIQUES CONTENUES DANS L'EAU

METHOD AND APPARATUS FOR PHOTOCATALYTIC OXIDATION OF WATER-BORNE CHEMICAL SPECIES

Abrégé français

La présente invention concerne un procédé et dispositif (10) de purification de l'eau permettant de détruire et d'éliminer des espèces chimiques. Le procédé consiste à faire descendre l'eau sur un élément ondulé incliné (12) fait en un catalyseur métallique tout en la soumettant à une lumière ultraviolette. L'élément ondulé est monté dans un chenal (11), un réservoir (15) étant disposé en aval du chenal incliné. Une pompe (17) permet de faire remonter l'eau du réservoir vers le haut du chenal. La source de lumière ultraviolette est soit une source artificielle, soit le soleil, soit enfin l'association des deux.

Abrégé anglais

A method of, and an apparatus (10) for, purifying water to destroy and remove
chemical species is disclosed involving passing the water down an undulating
inclined member (12) formed by a metallic catalyst whilst being exposed to
ultraviolet light. The enclosed surface is positioned in a trough (11), and a
tank (15) is positioned at the bottom of the inclined trough, and a pump (17)
is used to pump water from the tank to the top of the trough. The source of
ultraviolet light is an artificial source, or the sun, or both.

Revendications

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CLAIM:
1. A method of purifying water to destroy and remove
chemical species, wherein the water is passed down an
inclined surface formed by a metallic catalyst whilst being
exposed to ultraviolet light, said inlcined surface also
being such as to provide turbulence in the water.
2. A method as claimed in Claim 1, wherein the water
is pumped from a tank at the bottom of the inclined surface
to the top of the inclined surface, and gravitates down the
surface to the tank.
3. A method as claimed in Claim 1 or 2, wherein the
source of ultraviolet light is an artificial source, or the
sun, or both.
4. A method as claimed in any one of the preceding
claims, wherein the flow of water to the top of the
inclined surface is regulated.
5. An apparatus for purifying water for destroying
and removing chemical species, said apparatus comprising
means to provide an inclined surface of metallic catalyst,
and exposed to a source of ultraviolet light, said inclined
surface also being such as to provide turbulence in the
water.
6. An apparatus as claimed in Claim 5, further
including a tank positioned at the bottom of said inclined
surface, and a pump to pump water from said tank to the top
of said surface.
7. An apparatus as claimed in Claim 5 or 6, wherein
the source of ultraviolet light is an artificial source, or
the sun, or both.

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8. An apparatus as claimed in any one of Claims 5 to
7, wherein the means to provide said surface is a backing
member to which a layer of metallic catalyst is applied,
and said backing member with the metallic catalyst applied
thereto is positioned within a trough.
9. An apparatus as claimed in any one of Claims 5 to
8, wherein the means to provide said surface is undulated
along its length to provide a series of transverse ridges.
10. An apparatus as claimed in any one of Claims 5 to
9, wherein means are provided to regulate the flow of water
to the top of said surface.

Description

PCTiAU 9 5 / O O ~ 7
21 q3643 RECEI~IED O 4 h~ ~99
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WATE~ P~IRIFICATION
Technical Field
The ~resent in~ention relates to the ~urification
of contaminated water, and in ~articular an im~ro~ed method
and a~paratus for ~hotocatalytic oxidation of water borne
chemical s~ecies, for exam~le, microtoxins, phenolic
com~ounds, and ~esticide and insecticide com~ounds.
Background Art
Photocatalytic oxidation (destruction and
G~ovàl) of water borne chemical s~ecies has been the
subject of considerable re3earch in recent years, and has
involved oxidisation of a wide range of water borne
chemical s~ecies where catalytic surfaces, represented by a
suspen~ion of ~owdered catalytic material contained in a
closed sy4tem through which the contaminated water
circulates, is exposed to a photoactivating light source,
or alternati~ely a ~tationery catalytic 4urface is ~rovided
over which the contaminated water ~asses whil~t being
exposed to a source of ~hotoacti~ating ultra~iolet light
which may be sunlight or an artificial ~ource of
ultra~iolet light.
Disclosure of the Invention
We have found that the destruction and ~e~o~al of
chemical s~ecies cont~;n~nts in water can be improved
markedly if a stationary catalytic surface formed by-a
metallic catalyst, and inclined at an angle down which the
cont~m;nated water flows, is exposed to sunlight or
artificially generated ultra~iolet light.
The in~ention therefore en~isages a method of
purifying water to destroy and remo~e chemical s~ecies,
wherein the water is ~assed down an inclined surface formed
by a metallic catalyst, wh~lst being exposed to ultra~iolet
light, the incl~ned surface also being such as to ~ro~ide
turbulence in the water.
The in~ention also en~isages an a~aratus for
purifying water to de~troy and remove chemical s~ecies,
P~h4J

~CrIAU 9 5 1 0 0 3 7 3
2 1 9 3 6 4 3 RECEI\IEO O 4 APR 199
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said ap~aratus com~rising means to provide an inclined
surface of metallic catalyst, and exposed to a source of
ultraviolet light, said inclined surface alsobeing such as
to ~rovide turbulence in the water.
Brief Descri~tion of the Drawinas
one ~referred embodiment of the invention will
now be described with reference to the accom~anying
drawings, in which:
Figure 1 i8 a schematic ~lan view of the
a~aratus of the ~referred embodiment and to carry out the
method of the ~referred embodiment.
Figure 2 is a schematic side elevational view of
the a~paratus of Figure 1, and
Figure 3 is an enlarged view of the catalytic
surface of the embodiment of Figures 1 and 2.
Best Mode for Carryin~ Out the Invention
Referring to the drawings, the a~paratus,
~enerally indicated as 10, comprises an inclined trough 11
which contains an undulating member 12 ~roviding a series
of transverse ridges, and consisting of an outer layer 13
of a metallic catalyst ~u~orted as a thin film on a
backing 14 of glass fibre matting or glass fibre weave, or
any other material which ~rovides a suitable backing. The
trough 11 terminates at its lower end above an o~en to~ed
tank 15 into which water gravitating down the trough on the
metallic catalyst surface is delivered. Water in the tank
15 is drawn through a transfer ~i~e 16 by a ~um~ 17 which
~um~s the water u~ through a su~ply pi~e 18, contA;n;ng a
flow control valve 19, to a heA~r manifold 20 from which
the water flows to the to~ of the trough 11 and down the
trough to the tank 15. The ridges ~rovided by the
undulating member 12 assisting generating turbulence in the
flow of water down the trough which assists the
~hotocatalytic oxidation of the chemical s~ecies in the
contaminated water, whilst if a single ~as8 down the trough
is not sufficient to destroy and remove the chemical
~MEN~EDSHEET
~U

2 1 ~ 3 6 4 3
s~ecies, the water ean be cireulated around the ~y~tem as
many t~mes as are neeessary to aehle~e the desired result.
In this ~referred embodiment of the invention a
lam~ 21 ~roviding a ~ource of ultra~iolet l~ght i8
~ositioned above and ~arallel to the trough, and extends
along substantially the full length of the trough.
Alternatively, or in addition, sunlight may be u ed to
provide a natural souree of ultraviolet light when water
~urifieation during daylight hours is acee~table.
In the ~referred embodiment a metallic cataly~t
of titanium dioxide antaese has been found to be an
effeetive metallie eatalyst, although other metallie
catalysts may be effective to the same or lesser extent.
~MENDED8HEET
~E4/AU

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