CA2059932A1 - Destruction process - Google Patents
Destruction processInfo
- Publication number
- CA2059932A1 CA2059932A1 CA002059932A CA2059932A CA2059932A1 CA 2059932 A1 CA2059932 A1 CA 2059932A1 CA 002059932 A CA002059932 A CA 002059932A CA 2059932 A CA2059932 A CA 2059932A CA 2059932 A1 CA2059932 A1 CA 2059932A1
- Authority
- CA
- Canada
- Prior art keywords
- process according
- plate
- organic material
- disc
- titanium dioxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
- A62D3/10—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation
- A62D3/17—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation to electromagnetic radiation, e.g. emitted by a laser
- A62D3/176—Ultraviolet radiations, i.e. radiation having a wavelength of about 3nm to 400nm
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J19/12—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
- B01J19/122—Incoherent waves
- B01J19/123—Ultra-violet light
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
- B01J19/1887—Stationary reactors having moving elements inside forming a thin film
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/20—Organic substances
- A62D2101/22—Organic substances containing halogen
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/20—Organic substances
- A62D2101/26—Organic substances containing nitrogen or phosphorus
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/20—Organic substances
- A62D2101/28—Organic substances containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen
Abstract
DESTRUCTION PROCESS A process for the decomposition of photocatically degradable organic material includes exposing the organic material to ultraviolet light as the material is passing across the surface of a spinning disc. The surface of the disc carries anatase titanium dioxide adhering to the disc. The anatase titanium dioxide acts as a catalyst in the degradation process and preferably has a high surface area. Organic materials such as hydrocarbons alcohols, acids, esters and others are destroyed by this enviromnentally acceptable process.
Description
3 ~ .
This invention relates to a destruction process and particularly to a process for the decomposition of organic materi~l by ultraviolet light.
According to the present ;nvention a process for the 5 decomposition of photocatalytically degradable organic material comprises exposing said organic material in fluid form to ultraviolet light and passing said orgar~ic material across the surface of a plate-like member rotating about a central axis perpendicular to the radial plane of said mem~r thereby accelerating said organic material ~o radially outwardly of said axis across said surface of said member which carries anatase titanium dioxide adhering to said surface.
Generally speaking tbis invention makes use of a so-called "spinning disc reactor". This type of reactor includes within a reaction chamber a plate-like member or an assembly of a plurality of such 5 members which is rotated about its central axis, usually a vertical ax~s, but a horizontal axis, or any other orientation is not e~ccluded, to ef~ect transfer of a liquid material from the central al~is radially across the plate or plates to agitate and distNrb said liquid materiaL Usually the liquid w~ll be transferred either horizontally or vertically 20 depending on the orientation of the plate. This t~e of reactor has now been found to be of value in promoting the degradation of photodegradable org~c materials since it is designed to maximise turbulence within a very ~hin liquid filIrL This high degree of turbulence facilitates the mass transfer of oxygen, organic entitites, 25 rea~ion products and intermediates, and other reactive species :. .
This invention relates to a destruction process and particularly to a process for the decomposition of organic materi~l by ultraviolet light.
According to the present ;nvention a process for the 5 decomposition of photocatalytically degradable organic material comprises exposing said organic material in fluid form to ultraviolet light and passing said orgar~ic material across the surface of a plate-like member rotating about a central axis perpendicular to the radial plane of said mem~r thereby accelerating said organic material ~o radially outwardly of said axis across said surface of said member which carries anatase titanium dioxide adhering to said surface.
Generally speaking tbis invention makes use of a so-called "spinning disc reactor". This type of reactor includes within a reaction chamber a plate-like member or an assembly of a plurality of such 5 members which is rotated about its central axis, usually a vertical ax~s, but a horizontal axis, or any other orientation is not e~ccluded, to ef~ect transfer of a liquid material from the central al~is radially across the plate or plates to agitate and distNrb said liquid materiaL Usually the liquid w~ll be transferred either horizontally or vertically 20 depending on the orientation of the plate. This t~e of reactor has now been found to be of value in promoting the degradation of photodegradable org~c materials since it is designed to maximise turbulence within a very ~hin liquid filIrL This high degree of turbulence facilitates the mass transfer of oxygen, organic entitites, 25 rea~ion products and intermediates, and other reactive species :. .
2 ~ 3 2 across the catalys~/liquid, and litluid/gas, interfaces within the system. Most other devices incorporating an immobilised TiO2 suffer from mass trans~er lirnitations.
The plate~like member usually has the forrn of a dlisc and the surface which is to contact the organic material can be provided with protrusions, indentations or can be corrugated~ porous or perforated.
the plate-like member is rotated liquid flows from the central axis radially outwardly across the surface of the rnember and is accelerated and agitated.
0 Usually the organic material to be treated in the process of the invention is introduced in the fonn of a fluid into the reactor at ths centre of the plate-like member and conveniently is i~troduced along the axis through a support for the member which also provides lhe rotational drive to the plate-like member from a suitably located electr~c motor or other rotational drive unit, e.g. a hydraulic motor.
The plate-like member can be ~ormed from any material which is sufISciently strong to withstand ~he stress geIlerated in the material during use. Preferably the matenal is substantially resistant to attack by any compound with which it is brought into contact dunng use. Typically the plate-like member is formed of glass~
- ceramic or preferably a metal such as stainless steel, nickel or titanium but other materials sucb as wood, porcus plastic and paper can be used. A borosilicate glass plate-like member has been found to be useful when the member is fonned of glass.
2~5~
Typically the pla~e-like member when in the form of a disc has a diameter of from 25 cm to 5 metres. The mernber can h~ve a thickness of from 0.05 mm to 50 mm, preferably from 0.25 mm to S
mm, especially from O.S mm to 2.S mm.
s If desired the plate can h~ve a series of concen~ric grooves on the ~Ipper surface to be contacted with the li~d. V-shaped grooves presenting a continuously decreasing gradient to the liquid as it travels across the sur~ace of the plate-like member increase the retention of the liquid on the surface at higher rotational speeds of 0 the member.
Generally spealcin~ the speed of rotation of the plate-lilce member is in the range 50 rpm to 10,0~ rpm and preferably in the range 100 rpm to 5000 rpm. llle speed of rotation affects the aceeleration of the liquid across the surface of the plate-like member.
The speed of rotation and ~e rate of flow of liquid onto the surfaee of the plate-like member are such that a thin film of the liquid is ~ormed on the rotating sur~ace of the member and this thin film is subjected during rotation to a high degree of turbulence as it is thrown radially outwardly of the mem~er.
Normally the plate-like member is mounted with its surface either vertical or horizontal and it is the upper surface across which the liquid is caused to ~low during ex~osure to ultraviolet ligh~.
l~e surface of the member in contac~ with the liquid carries a pho~oactive catalyst which promotes the degradation of the organic material. In the process of the present inventio~l the catalyst is 2 ~ 3 2 anatase titanium dioxide, typically that produced by the hydrolysis of a soluble titanium compolmd such as titanyl sulphate or titaluum tetrachloride and which after precipitation is calcined to produce the anatase titanium dioxi(!le. Preferably the calcination conditions are chosen so that the time and/or temperature is somewhat less than that which would be required to produce optimum pigmentary anatase titanium diox~de. The catalyst pre~erably has a high surface area of from 20 to 200 m2jgm. Typically a hydrated precipitate of titanium dioxide is calcined at a temperature of from 100C to 1000C
7 0 for l0 minutes to 1000 minutes. Usually tbe anatase titanium dioxide has a particle size of *om 0.001 micron to 1.0 micron.
If desired the anatase titanium dioxide can be produced by the oxidation of a titanium halide such as titanium tetrachloride under conditions such that the product has the desired high surface area.
The plate-like mem~er carries tbe active catalyst at least on the surface to be in direct contact with the li~id to be treated and, as a result of the method of preparatioll, usually both radial surfaces of the member are coated with the chosen catalyst. One suitable procedure employed to coat the member with the catalyst is to immerse the member in an aqueous dispersion of the anatase titanium dioxidc for a period of say 3 to 10 minutes and then d~ the treated plate member in an oven for a period of say 30 to 75 minutes at a temperature of 70C to 100C. l~is treatment proeedure is repeated until a desired eiEecti~e amount ~ the catalyst has been applied to the surface of the member. Using an aqueous dispeMion 2~9~3~ .
containing from S to 15 gram per li~re TiO~ a total of from 7 to 15 ;mmersion/dry~ng ~ycles produces a~ "active" member.
Other procedures can include immersion in solutions of organic titanium compounds, with precipitation of TiO2 by sol/gel 5 techn~ques, and pyrolysis of titan~um compounds directly onto the sur~ace of the member. Additionally other support lmaterials can be coated w~th TiO2 and then attached to the sur~ace of the member The organic material to be treated in the process of the invention is in the form of a fluid during treatment. Where the 0 organic material to be degraded is a liquid itself then it can be treated directly. However the organic can be dissolved or dispersed in water or in any other suitable medium prior to treatment. Aqueous solutions are preferred since the presence of water acts as a saurce for hydroxyl radicals and &cilitates the transport of o7ygen across the 5 liquid/gas and solid/liquid interface. Typically the aqueous solution of the organic can have any pH value but pre~erably is acidic having a pH less than 7 and more preferably less than 4.
Activatioll of the anatase titanium dioxide catalyst is ensured ~ exp;osing the catalyst to the effect of ultraviolet light. The liquid to 2 o be treated is exposed to the light as it is in contact with the surface of the plate~ e mem~er and whilst ultraviolet light of any wavelength caII be used it has been found that light emitted by so-called low pressure lamps is more effective in promoting degradation of the organic materia1. Typically UV light of up to 400 nanometers can be ~5~9~
used but the mos~ preferred light is that h~ving a wavelength of from 240 t~ 280 nm.
The process can be operated batchwise or continuously. In batch operation liquid to be treated is held in a holding tank and 5 recycled across the surface of the rotating pla~e member until all n~cessary degradation has been completed. Al~ernatively continuous operation can be ef~ected if the re~guired degradation is obtained by a single pass across the surface of the plate member or by a succession o~ passes acrcss a number of different plate members. Usually 0 suitable analytical means will be employed to test the extent of degradation prior to discharge of water to the environrnent.
Any organic compound which is capable of photodegradation can be treated by the method of the invention. Depending on the exac~ nature of ~he organ~c material various by-products can be 5 obtaine~. For those organic compounds composed solely of carbon hydrogen and oxygen the process produces wa~er and carbon dioxide as the degradation products. For organic rnaterials contai~ing halogen additionally dilute rnineral acid is a degradation product.
The process, in any event, produces relatively easily handleable 2 o chemicals from often complex organic compounds.
Usually the process of the invention is carried out at room temperature with the rotating plate mounted in a suitable confining reactor equipped with a suitable source of ultraviolet light.
Typical organic compounds which can be treated in 25 acsord~nce with the invention are aliphatic or aromatic :
hydrocarbons, alcohols, acids, esters, ketones, amines and halogen substituted compounds. Pesticides are other environmentally ha2ardolls organic products eminently suitable for treatment by the process of the invention.
The invention is illustrated in the following Examples in which app~atus as shown in the accompanying drawing was used.
In the drawing:
Figure 1 is a diagrammatic representation of the overall layout, 0 Figure 2 is one form of reactort and lFigure 3 is an alternative form of reactor.
As shown the apparatus includes a reactor chamber 1 having mounte~l borizontally therein a rotatable disc 2 on a hollow shaft 3 coupled to a motor 4. A storage tank S has an outlet 6 in the base of the tank 5 ~hrough which the contents of the tank can be dra~ned through pipe 7. The outlet 6 is also coupled to a pump 8 to feed the contents of the tank S through the hollow shaft 3 to the upper su~face of the disc 2. The base of the reactor chamber 1 has an outlet 9 to a pllmp 10 and a return pipe 11 to the tank S.
Figure 2 illustrates one ~orm of reactor chamber 1 in which there is horizontally mounted lamps 12 to produce ultraviolet light.
The lamp 12 ex:tends across a diameter of the disc 2.
In Figure 3 an alternative arrangement of reactor chamber 1 is shown in which the lamp 12 is mounted vertically above but axially in :
9 3 ~
line with the axis of the disc. A reflector 13 is positioned to direct the light onto the di~ 2.
The reactor chamber 1 is equipped with an axial deflector plate 14 to deflect flQW of liquid from the hollow shaft 3 onto the s upper surface of the diss 2. The tank S is equipped with a stirrer lS.
As used the rotatable disc 2 was forrned from borosilicate glass and had a diameter of 38 cm. The speed of rota~ion o~ the disc in the following experiments was 350 rpm and a liquid flow rate across the upper surface of the disc 2 was maintained at 180 litres per hour. The lo temperature within the reactor cham~er 1 was maintained at about 25C.
The rotatable disc 2 carried a coating of anatase titanium dioxide the particular ~o~m of which is described in the following examples. The disc was coated by preparing a~ aqueous slurry of the :L5 ti~anium dioxide containing 10 gpl by milling ~e anatase titanium dioxide with water in the required amount and the disc 2 was then immersed in the slurry for a period of S minutes. The disc was rem~ved from the slurry and dried in an oven at 90C ~or one hour.
This particular coating and drying procedure was repeated for a total 20 of 10 cycles. The disc was then washed tlhoroughly after the last drying stage to rer~o~e any loose titanium dioxide particles from the surface.
le 1 A 38 cm disc o~ borosilicate ~lass was coated with a thin film 25 of TiO2 as described previously.
20~9~32 l'he disc was athched to the shah 3 and run at 350 rpm. An aqueous solution ~ontaining 1~0 micromoles per litre of 4-chlorophenol was pumped over the disc at the rate of 180 ~/hr whilst the disc was illuminated with UV light as shown in Figure ~ from two s 15 watt low-pressure lamps at differen~ intensities~ Solution pH was maintained at pH 3.1 wi~h 2% H2SO,~.
Rates o~ reac~ion calculated from experimental data were as follows:-W inten~ityR~tQofR~ctiOn (KR) Wln Experiment A14.0 0.563 E~xperiment B27.9 0.652 KR is de~med by reference ~o the Langmuir-Hinshelwood Kinetics.
5 13~a~2 Experimen~al collditions were similar to Example 1 except that the low pressure lamp was substituted by a 400 watt medium pressure lamp as in Figure 3.
Results were as ~ollows:
2 o UV int~l~t~ of Re~iQII ~K1R.) w~-2 Mi~mo~es,/min/litre Experiment A27.9 0.228 Experiment B49.0 0.245 Experiment C98.2 0.381 Experiment D246.0 0.418 2059~3~
1~
The above results demonstrate that the use of a low pressure lamp increases the speed of destru~ion ~ 4-chloro-phenol, compared with a medium pressure, higher output, lamp. This increase could not be accounted for in ~er~T~ vf a pho~ochemical reactiorl.
5 E:~am~e ~
E~xamples 1 and 2 were repeated with a~ initial concentration of 1Q0 micromoles/litre oE salicylic ac4id.
UV Inte~sit~ mp _ ate o~ Re~ction (KR) Wm-2 Micromoles,/m;n/l.i¢~
0 E~periment A ~7.9 Low 0.419 Pressure Experiment B 246.0 Medium 0.185 Pressure The rate of de~adation of the salicylic acid is slower than Eor 5 4-cblorophenol, but, once again, the low pressure lamp is more effective tban the medium pressure lamp.
E~LE 4 Ex~rimental conditions were similar to Experiment 1 using two 15W l~w pressure lamps and an initial concen~ration of 100 20 micromoles per litre of 4-chlorophenol. Solution pH was controlled by addition of acid or alkali as required.
~lutio~ D~ ~a~ic te ~ Re~tiQn Microllloles/min/litre Experiment A 3 (:~lorophenol 0.418 Exper~ment B 5 Chlorophenol 0.~57 Experiment C1l Chlorophellol 0.121
The plate~like member usually has the forrn of a dlisc and the surface which is to contact the organic material can be provided with protrusions, indentations or can be corrugated~ porous or perforated.
the plate-like member is rotated liquid flows from the central axis radially outwardly across the surface of the rnember and is accelerated and agitated.
0 Usually the organic material to be treated in the process of the invention is introduced in the fonn of a fluid into the reactor at ths centre of the plate-like member and conveniently is i~troduced along the axis through a support for the member which also provides lhe rotational drive to the plate-like member from a suitably located electr~c motor or other rotational drive unit, e.g. a hydraulic motor.
The plate-like member can be ~ormed from any material which is sufISciently strong to withstand ~he stress geIlerated in the material during use. Preferably the matenal is substantially resistant to attack by any compound with which it is brought into contact dunng use. Typically the plate-like member is formed of glass~
- ceramic or preferably a metal such as stainless steel, nickel or titanium but other materials sucb as wood, porcus plastic and paper can be used. A borosilicate glass plate-like member has been found to be useful when the member is fonned of glass.
2~5~
Typically the pla~e-like member when in the form of a disc has a diameter of from 25 cm to 5 metres. The mernber can h~ve a thickness of from 0.05 mm to 50 mm, preferably from 0.25 mm to S
mm, especially from O.S mm to 2.S mm.
s If desired the plate can h~ve a series of concen~ric grooves on the ~Ipper surface to be contacted with the li~d. V-shaped grooves presenting a continuously decreasing gradient to the liquid as it travels across the sur~ace of the plate-like member increase the retention of the liquid on the surface at higher rotational speeds of 0 the member.
Generally spealcin~ the speed of rotation of the plate-lilce member is in the range 50 rpm to 10,0~ rpm and preferably in the range 100 rpm to 5000 rpm. llle speed of rotation affects the aceeleration of the liquid across the surface of the plate-like member.
The speed of rotation and ~e rate of flow of liquid onto the surfaee of the plate-like member are such that a thin film of the liquid is ~ormed on the rotating sur~ace of the member and this thin film is subjected during rotation to a high degree of turbulence as it is thrown radially outwardly of the mem~er.
Normally the plate-like member is mounted with its surface either vertical or horizontal and it is the upper surface across which the liquid is caused to ~low during ex~osure to ultraviolet ligh~.
l~e surface of the member in contac~ with the liquid carries a pho~oactive catalyst which promotes the degradation of the organic material. In the process of the present inventio~l the catalyst is 2 ~ 3 2 anatase titanium dioxide, typically that produced by the hydrolysis of a soluble titanium compolmd such as titanyl sulphate or titaluum tetrachloride and which after precipitation is calcined to produce the anatase titanium dioxi(!le. Preferably the calcination conditions are chosen so that the time and/or temperature is somewhat less than that which would be required to produce optimum pigmentary anatase titanium diox~de. The catalyst pre~erably has a high surface area of from 20 to 200 m2jgm. Typically a hydrated precipitate of titanium dioxide is calcined at a temperature of from 100C to 1000C
7 0 for l0 minutes to 1000 minutes. Usually tbe anatase titanium dioxide has a particle size of *om 0.001 micron to 1.0 micron.
If desired the anatase titanium dioxide can be produced by the oxidation of a titanium halide such as titanium tetrachloride under conditions such that the product has the desired high surface area.
The plate-like mem~er carries tbe active catalyst at least on the surface to be in direct contact with the li~id to be treated and, as a result of the method of preparatioll, usually both radial surfaces of the member are coated with the chosen catalyst. One suitable procedure employed to coat the member with the catalyst is to immerse the member in an aqueous dispersion of the anatase titanium dioxidc for a period of say 3 to 10 minutes and then d~ the treated plate member in an oven for a period of say 30 to 75 minutes at a temperature of 70C to 100C. l~is treatment proeedure is repeated until a desired eiEecti~e amount ~ the catalyst has been applied to the surface of the member. Using an aqueous dispeMion 2~9~3~ .
containing from S to 15 gram per li~re TiO~ a total of from 7 to 15 ;mmersion/dry~ng ~ycles produces a~ "active" member.
Other procedures can include immersion in solutions of organic titanium compounds, with precipitation of TiO2 by sol/gel 5 techn~ques, and pyrolysis of titan~um compounds directly onto the sur~ace of the member. Additionally other support lmaterials can be coated w~th TiO2 and then attached to the sur~ace of the member The organic material to be treated in the process of the invention is in the form of a fluid during treatment. Where the 0 organic material to be degraded is a liquid itself then it can be treated directly. However the organic can be dissolved or dispersed in water or in any other suitable medium prior to treatment. Aqueous solutions are preferred since the presence of water acts as a saurce for hydroxyl radicals and &cilitates the transport of o7ygen across the 5 liquid/gas and solid/liquid interface. Typically the aqueous solution of the organic can have any pH value but pre~erably is acidic having a pH less than 7 and more preferably less than 4.
Activatioll of the anatase titanium dioxide catalyst is ensured ~ exp;osing the catalyst to the effect of ultraviolet light. The liquid to 2 o be treated is exposed to the light as it is in contact with the surface of the plate~ e mem~er and whilst ultraviolet light of any wavelength caII be used it has been found that light emitted by so-called low pressure lamps is more effective in promoting degradation of the organic materia1. Typically UV light of up to 400 nanometers can be ~5~9~
used but the mos~ preferred light is that h~ving a wavelength of from 240 t~ 280 nm.
The process can be operated batchwise or continuously. In batch operation liquid to be treated is held in a holding tank and 5 recycled across the surface of the rotating pla~e member until all n~cessary degradation has been completed. Al~ernatively continuous operation can be ef~ected if the re~guired degradation is obtained by a single pass across the surface of the plate member or by a succession o~ passes acrcss a number of different plate members. Usually 0 suitable analytical means will be employed to test the extent of degradation prior to discharge of water to the environrnent.
Any organic compound which is capable of photodegradation can be treated by the method of the invention. Depending on the exac~ nature of ~he organ~c material various by-products can be 5 obtaine~. For those organic compounds composed solely of carbon hydrogen and oxygen the process produces wa~er and carbon dioxide as the degradation products. For organic rnaterials contai~ing halogen additionally dilute rnineral acid is a degradation product.
The process, in any event, produces relatively easily handleable 2 o chemicals from often complex organic compounds.
Usually the process of the invention is carried out at room temperature with the rotating plate mounted in a suitable confining reactor equipped with a suitable source of ultraviolet light.
Typical organic compounds which can be treated in 25 acsord~nce with the invention are aliphatic or aromatic :
hydrocarbons, alcohols, acids, esters, ketones, amines and halogen substituted compounds. Pesticides are other environmentally ha2ardolls organic products eminently suitable for treatment by the process of the invention.
The invention is illustrated in the following Examples in which app~atus as shown in the accompanying drawing was used.
In the drawing:
Figure 1 is a diagrammatic representation of the overall layout, 0 Figure 2 is one form of reactort and lFigure 3 is an alternative form of reactor.
As shown the apparatus includes a reactor chamber 1 having mounte~l borizontally therein a rotatable disc 2 on a hollow shaft 3 coupled to a motor 4. A storage tank S has an outlet 6 in the base of the tank 5 ~hrough which the contents of the tank can be dra~ned through pipe 7. The outlet 6 is also coupled to a pump 8 to feed the contents of the tank S through the hollow shaft 3 to the upper su~face of the disc 2. The base of the reactor chamber 1 has an outlet 9 to a pllmp 10 and a return pipe 11 to the tank S.
Figure 2 illustrates one ~orm of reactor chamber 1 in which there is horizontally mounted lamps 12 to produce ultraviolet light.
The lamp 12 ex:tends across a diameter of the disc 2.
In Figure 3 an alternative arrangement of reactor chamber 1 is shown in which the lamp 12 is mounted vertically above but axially in :
9 3 ~
line with the axis of the disc. A reflector 13 is positioned to direct the light onto the di~ 2.
The reactor chamber 1 is equipped with an axial deflector plate 14 to deflect flQW of liquid from the hollow shaft 3 onto the s upper surface of the diss 2. The tank S is equipped with a stirrer lS.
As used the rotatable disc 2 was forrned from borosilicate glass and had a diameter of 38 cm. The speed of rota~ion o~ the disc in the following experiments was 350 rpm and a liquid flow rate across the upper surface of the disc 2 was maintained at 180 litres per hour. The lo temperature within the reactor cham~er 1 was maintained at about 25C.
The rotatable disc 2 carried a coating of anatase titanium dioxide the particular ~o~m of which is described in the following examples. The disc was coated by preparing a~ aqueous slurry of the :L5 ti~anium dioxide containing 10 gpl by milling ~e anatase titanium dioxide with water in the required amount and the disc 2 was then immersed in the slurry for a period of S minutes. The disc was rem~ved from the slurry and dried in an oven at 90C ~or one hour.
This particular coating and drying procedure was repeated for a total 20 of 10 cycles. The disc was then washed tlhoroughly after the last drying stage to rer~o~e any loose titanium dioxide particles from the surface.
le 1 A 38 cm disc o~ borosilicate ~lass was coated with a thin film 25 of TiO2 as described previously.
20~9~32 l'he disc was athched to the shah 3 and run at 350 rpm. An aqueous solution ~ontaining 1~0 micromoles per litre of 4-chlorophenol was pumped over the disc at the rate of 180 ~/hr whilst the disc was illuminated with UV light as shown in Figure ~ from two s 15 watt low-pressure lamps at differen~ intensities~ Solution pH was maintained at pH 3.1 wi~h 2% H2SO,~.
Rates o~ reac~ion calculated from experimental data were as follows:-W inten~ityR~tQofR~ctiOn (KR) Wln Experiment A14.0 0.563 E~xperiment B27.9 0.652 KR is de~med by reference ~o the Langmuir-Hinshelwood Kinetics.
5 13~a~2 Experimen~al collditions were similar to Example 1 except that the low pressure lamp was substituted by a 400 watt medium pressure lamp as in Figure 3.
Results were as ~ollows:
2 o UV int~l~t~ of Re~iQII ~K1R.) w~-2 Mi~mo~es,/min/litre Experiment A27.9 0.228 Experiment B49.0 0.245 Experiment C98.2 0.381 Experiment D246.0 0.418 2059~3~
1~
The above results demonstrate that the use of a low pressure lamp increases the speed of destru~ion ~ 4-chloro-phenol, compared with a medium pressure, higher output, lamp. This increase could not be accounted for in ~er~T~ vf a pho~ochemical reactiorl.
5 E:~am~e ~
E~xamples 1 and 2 were repeated with a~ initial concentration of 1Q0 micromoles/litre oE salicylic ac4id.
UV Inte~sit~ mp _ ate o~ Re~ction (KR) Wm-2 Micromoles,/m;n/l.i¢~
0 E~periment A ~7.9 Low 0.419 Pressure Experiment B 246.0 Medium 0.185 Pressure The rate of de~adation of the salicylic acid is slower than Eor 5 4-cblorophenol, but, once again, the low pressure lamp is more effective tban the medium pressure lamp.
E~LE 4 Ex~rimental conditions were similar to Experiment 1 using two 15W l~w pressure lamps and an initial concen~ration of 100 20 micromoles per litre of 4-chlorophenol. Solution pH was controlled by addition of acid or alkali as required.
~lutio~ D~ ~a~ic te ~ Re~tiQn Microllloles/min/litre Experiment A 3 (:~lorophenol 0.418 Exper~ment B 5 Chlorophenol 0.~57 Experiment C1l Chlorophellol 0.121
Claims (13)
1. A process for the decomposition of photocatalytically degradable organic material comprising exposing said organic material in fluid form to ultraviolet light and passing said organic material across the surface of a plate-like member rotating about a central axis perpendicular to the radial plane of said member thereby accelerating said organic material radially outwardly of said axis across said surface of said member which carries anatase titanium dioxide adhering to said surface.
2. A process according to claim 1 in which the anatase titanium dioxide has a surface area of from 20 to 200 m2/gm.
3. A process according to claim 1 in which the anatase titanium dioxide has a particle size of from 0.001 to 1.0 micron.
4. A process according to claim 1 in which the ultraviolet light is that emitted by a low pressure lamp.
5. A process according to claim 1 in which the ultraviolet light has a wavelength of up to 400 nanometers.
6. A process according to claim 1 in which the plate-like member has the form of a disc having a diameter of from 25 cm to 5 metres.
7. A process according to claim 1 in which the plate-like member has a thickness of from 0.05 mm to 50 mm.
8. A process according to claim 1 in which the plate-like member is rotated at a speed of from 50 rpm to 10,000 rpm.
9. A process according to claim 8 in which the plate-like member is rotated at a speed of from 100 rpm to 5,000 rpm.
10. A process according to claim 1 in which the said organic material is a dispersion or a solution in water.
11. A process according to claim 10 in which the water dispersion or solution is acidic.
12. A process according to claim 11 in which the water dispersion or solution has a pH of less than 4.
13. A process according to claim 1 in which the said organic material is a hydrocarbon, an alcohol, an acid, an ester, a ketone, an amine or a halogen substituted compound.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US9102766.4 | 1991-02-09 | ||
| GB919102766A GB9102766D0 (en) | 1991-02-09 | 1991-02-09 | Destruction process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2059932A1 true CA2059932A1 (en) | 1992-08-10 |
Family
ID=10689774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002059932A Abandoned CA2059932A1 (en) | 1991-02-09 | 1992-01-23 | Destruction process |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5308458A (en) |
| EP (1) | EP0499362B1 (en) |
| AU (1) | AU646133B2 (en) |
| CA (1) | CA2059932A1 (en) |
| DE (1) | DE69203877T2 (en) |
| DK (1) | DK0499362T3 (en) |
| ES (1) | ES2075602T3 (en) |
| GB (2) | GB9102766D0 (en) |
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|---|---|---|---|---|
| DE69421734T2 (en) * | 1993-03-11 | 2000-07-13 | Fuji Electric Co Ltd | Pollutant removal procedures |
| AU709825B2 (en) * | 1994-06-27 | 1999-09-09 | Ronald William Arthur | Water Purification |
| AUPM646094A0 (en) * | 1994-06-27 | 1994-07-21 | Arthur, Ronald W. | An improved method for the photocatalytic oxidation of water borne chemical species |
| US5698177A (en) * | 1994-08-31 | 1997-12-16 | University Of Cincinnati | Process for producing ceramic powders, especially titanium dioxide useful as a photocatalyst |
| US5547655A (en) * | 1994-11-28 | 1996-08-20 | Chou; Tse-Chaun | Recovery and regeneration of sulfuric acid |
| US5564065A (en) * | 1995-01-19 | 1996-10-08 | Chelsea Group Ltd. | Carbon monoxide air filter |
| US5494643A (en) * | 1995-04-04 | 1996-02-27 | University Of New Mexico | Method and apparatus for optimizing control of an immobilized film photoreactor |
| US6238738B1 (en) | 1996-08-13 | 2001-05-29 | Libbey-Owens-Ford Co. | Method for depositing titanium oxide coatings on flat glass |
| EP0850676B1 (en) * | 1996-12-27 | 2002-03-27 | Nippon Shokubai Co., Ltd. | Use of a catalyst for removing organic halogen compounds and method for removing organic halogen compounds |
| FR2760445B1 (en) * | 1997-03-04 | 1999-04-16 | Lyonnaise Eaux Eclairage | PROCESS FOR TREATING WATER CONTAINING ORGANIC IMPURITIES AND MICROORGANISMS |
| US6054227A (en) * | 1997-03-14 | 2000-04-25 | Ppg Industries Ohio, Inc. | Photocatalytically-activated self-cleaning appliances |
| US6027766A (en) * | 1997-03-14 | 2000-02-22 | Ppg Industries Ohio, Inc. | Photocatalytically-activated self-cleaning article and method of making same |
| US7096692B2 (en) * | 1997-03-14 | 2006-08-29 | Ppg Industries Ohio, Inc. | Visible-light-responsive photoactive coating, coated article, and method of making same |
| KR100253095B1 (en) * | 1997-12-05 | 2000-04-15 | 윤종용 | Photo-oxidation equipment, water treatment system and water treating method thereby for semiconductor fabricating |
| WO1999064357A1 (en) * | 1998-06-12 | 1999-12-16 | Kabushiki Kaisha Himeka Engineering | Apparatus for photocatalytic reaction with and method for fixing photocatalyst |
| US6233748B1 (en) * | 1998-07-31 | 2001-05-22 | Integrated Medical Systems, Inc. | Environmental protection system |
| GB9903474D0 (en) * | 1999-02-17 | 1999-04-07 | Univ Newcastle | Process for the conversion of a fluid phase substrate by dynamic heterogenous contact with an agent |
| US6248235B1 (en) | 1999-03-30 | 2001-06-19 | Robin Scott | Fluid purification system |
| GB9913315D0 (en) | 1999-06-08 | 1999-08-11 | Pilkington Plc | Improved process for coating glass |
| EP1162179B1 (en) * | 2000-06-10 | 2004-09-15 | Degussa AG | Photocatalytic process |
| US6902397B2 (en) * | 2002-08-01 | 2005-06-07 | Sunstar Americas, Inc. | Enhanced dental hygiene system with direct UVA photoexcitation |
| GB0218314D0 (en) | 2002-08-07 | 2002-09-11 | Albagaia Ltd | Apparatus and method for treatment of chemical and biological hazards |
| US6783740B2 (en) * | 2002-09-30 | 2004-08-31 | Northrop Grumman Corporation | Sintered glass bead filter with active microbial destruction |
| US7125527B2 (en) * | 2003-09-05 | 2006-10-24 | Kinetichem, Inc. | Methods of operating surface reactors and reactors employing such methods |
| GB2419100A (en) * | 2004-10-15 | 2006-04-19 | Protensive Ltd | Spinning disc reactor with cross-flow filtration or solvation |
| US7927553B2 (en) * | 2007-06-15 | 2011-04-19 | Din-Ping Tsai | Photocatalytic reactor with movable conformal light guiding plate |
| US20100213046A1 (en) * | 2009-01-06 | 2010-08-26 | The Penn State Research Foundation | Titania nanotube arrays, methods of manufacture, and photocatalytic conversion of carbon dioxide using same |
| CN102502941A (en) * | 2011-11-03 | 2012-06-20 | 重庆理工大学 | Method for treating organic wastewater through photocatalysis by inclined double-pole liquid film |
| US9573297B2 (en) * | 2011-11-21 | 2017-02-21 | Reza Reza Youssefi | Method and system for enhancing polymerization and nanoparticle production |
| CN113198410B (en) * | 2021-05-07 | 2022-07-19 | 山东师范大学 | Composite photocatalyst amplifying and synthesizing device and method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB328410A (en) * | 1929-04-03 | 1930-05-01 | Ernst Buhtz | An improved method and apparatus for irradiating substances |
| FR2058540A5 (en) * | 1969-09-15 | 1971-05-28 | Anvar | |
| DE2343407A1 (en) * | 1972-08-30 | 1974-03-14 | Allied Chem | REACTION PROCESS AND DEVICE FOR IMPLEMENTING THE SAME |
| EP0023745B1 (en) * | 1977-12-01 | 1985-05-08 | Imperial Chemical Industries Plc | Process and apparatus for effecting mass transfer |
| DE2965174D1 (en) * | 1978-02-21 | 1983-05-19 | Ici Plc | Chemical process on the surface of a rotating body with subsequent discharge of the reaction product |
| SE8001635L (en) * | 1979-03-05 | 1980-09-06 | Franz Bohnensieker | PROCEDURE FOR STERILIZING HEAVY SHOES AND DEVICE FOR PERFORMING THE PROCEDURE |
| US4303486A (en) * | 1979-03-28 | 1981-12-01 | Board Of Regents, University Of Texas System | Methods of photocatalytic decarboxylation of saturated carboxylic acid |
| DE3071856D1 (en) * | 1979-05-31 | 1987-01-22 | Ici Plc | Process and apparatus for effecting mass transfer |
| ATE13016T1 (en) * | 1980-12-08 | 1985-05-15 | Ici Plc | MASS EXCHANGE DEVICE. |
| DE3272341D1 (en) * | 1981-10-26 | 1986-09-04 | Ici Plc | Centrifugal gas-liquid contact apparatus |
| EP0080311B1 (en) * | 1981-11-24 | 1986-01-15 | Imperial Chemical Industries Plc | Contacting device |
| AU600289B2 (en) * | 1986-07-22 | 1990-08-09 | Commonwealth Scientific And Industrial Research Organisation | Coating photoactive metal oxides onto substrates |
| CA1287829C (en) * | 1986-10-02 | 1991-08-20 | Cooper H. Langford | Composite photocatalyst for refractory waste degradation |
| JP2739128B2 (en) * | 1987-07-27 | 1998-04-08 | ウイスコンシン アラムニ リサーチ ファンデーション | Decomposition method of organic chemicals by titanium ceramic membrane |
| US4892712A (en) * | 1987-09-04 | 1990-01-09 | Nutech Energy Systems Inc. | Fluid purification |
| JPH0611378B2 (en) * | 1988-10-18 | 1994-02-16 | 工業技術院長 | Method for removing volatile organic chlorine compounds |
| US5045288A (en) * | 1989-09-15 | 1991-09-03 | Arizona Board Of Regents, A Body Corporate Acting On Behalf Of Arizona State University | Gas-solid photocatalytic oxidation of environmental pollutants |
| GB9102767D0 (en) * | 1991-02-09 | 1991-03-27 | Tioxide Group Services Ltd | Destruction process |
-
1991
- 1991-02-09 GB GB919102766A patent/GB9102766D0/en active Pending
-
1992
- 1992-01-20 GB GB9201111A patent/GB2252707B/en not_active Expired - Fee Related
- 1992-01-20 DE DE69203877T patent/DE69203877T2/en not_active Expired - Fee Related
- 1992-01-20 ES ES92300473T patent/ES2075602T3/en not_active Expired - Lifetime
- 1992-01-20 DK DK92300473.3T patent/DK0499362T3/en active
- 1992-01-20 EP EP92300473A patent/EP0499362B1/en not_active Expired - Lifetime
- 1992-01-22 AU AU10379/92A patent/AU646133B2/en not_active Ceased
- 1992-01-23 CA CA002059932A patent/CA2059932A1/en not_active Abandoned
- 1992-01-27 US US07/826,466 patent/US5308458A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB2252707A (en) | 1992-08-12 |
| EP0499362B1 (en) | 1995-08-09 |
| GB2252707B (en) | 1994-10-26 |
| DE69203877D1 (en) | 1995-09-14 |
| ES2075602T3 (en) | 1995-10-01 |
| DE69203877T2 (en) | 1995-12-07 |
| US5308458A (en) | 1994-05-03 |
| AU646133B2 (en) | 1994-02-10 |
| GB9201111D0 (en) | 1992-03-11 |
| EP0499362A1 (en) | 1992-08-19 |
| DK0499362T3 (en) | 1995-09-18 |
| GB9102766D0 (en) | 1991-03-27 |
| AU1037992A (en) | 1992-08-13 |
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