[go: up one dir, main page]

WO1993017971A1 - Matieres et procedes permettant la photocatalyse amelioree de composes organiques - Google Patents

Matieres et procedes permettant la photocatalyse amelioree de composes organiques Download PDF

Info

Publication number
WO1993017971A1
WO1993017971A1 PCT/US1992/001790 US9201790W WO9317971A1 WO 1993017971 A1 WO1993017971 A1 WO 1993017971A1 US 9201790 W US9201790 W US 9201790W WO 9317971 A1 WO9317971 A1 WO 9317971A1
Authority
WO
WIPO (PCT)
Prior art keywords
beads
particles
bead
water
oil
Prior art date
Application number
PCT/US1992/001790
Other languages
English (en)
Inventor
Adam Heller
James R. Brock
Original Assignee
Board Of Regents, The University Of Texas System
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Board Of Regents, The University Of Texas System filed Critical Board Of Regents, The University Of Texas System
Priority to AU23216/92A priority Critical patent/AU2321692A/en
Priority to PCT/US1992/001790 priority patent/WO1993017971A1/fr
Publication of WO1993017971A1 publication Critical patent/WO1993017971A1/fr

Links

Classifications

    • 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
    • B01J19/127—Sunlight; Visible light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
    • C02F3/344—Biological treatment of water, waste water, or sewage characterised by the microorganisms used for digestion of mineral oil
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/10—Photocatalysts

Definitions

  • This invention relates to materials and methods for aggregating, biodegrading, and photocatalyzing the oxidation of organic compounds floating on water, such as those typically resulting from an oil spill.
  • Organic compounds invade the world's waterways from many sources in addition to oil spills. For example, refineries located along rivers often introduce substantial amounts of organic products and waste into the water. Organic compounds from landfills and waste sites can leach down to water tables below the earth's surface.
  • Recreational motorboats often exhaust and leak a certain amount of oil and gasoline into lakes and reservoirs. These are just a few of the sources of organic compounds entering water resources.
  • the problems associated with petroleum in water may be ameliorated over time thorough various natural treatment processes. Among these are evaporation, dissolution, dispersion, adsorption onto suspended particulate matter, sinking, and microbial oxidation.
  • photocatalytic oxidation (alternatively referred to as photoassisted or photochemical oxidation, or as photooxidation) . Since oil and related organic materials generally have a lower density than water, they tend to float on the surface of water as a film, and are thereby exposed to a significant amount of solar illumination. Natural photocatalytic oxidation of floating oil films has been the subject of several studies, and it is generally known that oxidation of organic compounds in oil can be naturally photocatalyzed and that the oxidation products are generally more water soluble and/or less refractory compounds, such as alcohols, ketones, and carboxylic acids. These photooxidation products may be environmentally less harmful, because after dissolving, they tend to be more readily attacked by microorganisms for eventual complete oxidation to C0 2 .
  • Another technique which has been suggested is the use of organic photosensitizers to photocatalyze the oxidation of the oil film.
  • a potential problem with this type of technique is that the wavelengths needed to excite the oil-dissolved photosensitizer are often absorbed by other constituents of the oil film. Furthermore, even if the photosensitizer has been excited by a photon, it may be "quenched", i.e. transfer energy to another dissolved compound that is not an adequate photosensitizer. Therefore, this technique has not been ⁇ , widely accepted.
  • One broad aspect of the present invention provides a bead having an exterior surface that is at least
  • coated beads contemplated by this invention generally have an equivalent diameter of less than about 2 millimeters.
  • equivalent diameter is used herein to mean the diameter of a sphere which would have the same volume as the bead. Thus, for example, if the bead has a volume of pi/6 mm 3 , it has an equivalent diameter of 1 mm.
  • water floatable means that the coated bead has such physical characteristics that is will float at or near the surface of water either indefinitely (e.g. until washed ashore or dissolved, or for a sufficient 35 period of time such that the material coated on the bead may be effective to assist in, induce or accelerate oxidation of organic compounds floating on the water under sunlight.
  • the coated bead may be made floatable in at least three ways. First, the coated bead may have a density less than the density of water. Second, the coated bead may be treated such that it is substantially hydrophobic (i.e. oleophilic) , and therefore be kept by interfacial forces on the film near the water surface.
  • the coated bead may be made sufficiently small for the sedimentation velocity to be substantially reduced, particularly in viscous oils.
  • their precipitation time through an oil film may be long enough such that they are in contact with the oil film for a sufficient length of time to effect photooxidation thereof.
  • the coated bead size could be small enough such that the sedimentation velocity would be on the order of 10 "6 centimeters per second, thereby making their precipitation time through a typical oil film longer than about 24 hours.
  • the coated beads provided by this invention when used to treat oil slicks on the surface of an ocean or sea, have a density less than the density of sea water.
  • the coated beads will therefore tend to float along with the oil slick on the surface of the sea water.
  • the coated beads preferably have a density less than the density of the water onto which they are to be dispersed.
  • the bead has a relatively high index of refraction, and the coating material has an even higher index of refraction.
  • the bead may tend to trap and waveguide light to the photocatalytic coating material. This is desirable, since generally the more light that reaches the photocatalytic coating material. the greater the photon flux for photoassisted oxidation of the oil by oxygen.
  • the photocatalytic coating material have an index of refraction of at least about 2.
  • the bead have an index of refraction of at least about 1.5 (as is typical of most Si0 2 - based glasses or 1.6 (as is typical of most ceramics) .
  • index of refraction is that measured at the sodium D-line near 589 n .
  • the index of refraction refers to the bead shell material only, and not the hollow (air) interior.
  • the coating material preferably comprises an n-type semiconductor having a band gap of at least about 2 eV.
  • the coating material is also preferably photoconductive.
  • Specific compounds which may be used alone or in combination as the coating material include titanium dioxide, zinc oxide, zinc sulfide, and iron oxide. Other compounds may be effective as photocatalysts, but may be less preferable either because of their toxicity, or because of their photodecomposition (i.e. photooxidation of their surface or photodissolution) .
  • the beads comprise an inorganic material, which generally may be coated readily with photocatalytic compounds.
  • hollow glass or hollow ceramic beads may be used.
  • the bead may comprise an organic material.
  • a photocatalytic coating material may tend to photocatalyze the oxidation of an organic bead material by oxygen
  • the bead preferably should be protected with an intermediate layer comprising a material which will not allow oxidization of the organic bead material or itself be oxidized by oxygen in a process photocatalyzed by the outer coating material.
  • the organic bead material may be, for example, a plastic material such as polyethylene or polypropylene.
  • the protective intermediate layer may be, for example, silicon dioxide or aluminum oxide.
  • each coated bead is preferably less than the thickness of the oil film to be treated.
  • the lower limit on the equivalent diameter of the coated beads is on the order of about one tenth of the wavelength of light. This is so because if the beads are smaller, their dielectric properties (including their index of refraction) tend to be averaged with those of the medium in which they are immersed, and light of appropriate wavelengths (e.g. longer than 200 nm) will not be substantially refracted or reflected at the particle-liquid interface. In order to optically guide and trap light, coated beads with an equivalent diameter of at least about 30-100 nm are thus preferred.
  • the coated beds provided by this invention have an equivalent diameter of less than about 200 microns, more preferably less than about 100 microns. and most preferably between about 10 and 30 microns, but have at least a 30 nm equivalent diameter.
  • the invention provides coated beads which are oil dispersible and water floatable and capable of accelerating the oxidation of hydrocarbons in the presence of oxygen and light.
  • oil dispersible as used herein means that the coated beads are capable of being dispersed in or on oil. That is, they may have a surface that makes them wetted by oil.
  • the present invention provides a method for treating an oil film floating on a body of water using the coated beads described above.
  • the method comprises the steps of dispersing a plurality of such coated beads on an oil film, and allowing the coated beads to be exposed to solar illumination and ambient air, thereby accelerating the oxidation of organic compounds in the oil film.
  • the coated beads Preferably, have an average equivalent diameter less than the average thickness of the oil film, and the coated beads float at or near the surface of the oil film.
  • light may be trapped by the beads and waveguided to the coating material.
  • the present invention provides a method for treating an oil film floating on a body of water comprising the steps of dispersing a plurality of water floatable particles on oil film, the particles comprising a material that under illumination and in the presence of air is capable of oxidizing organic compounds in the oil film.
  • the particles are allowed to be exposed to solar illumination and ambient air, thereby accelerating the oxidation of organic compounds in the oil film.
  • the term "particle” is intended to mean any form of solid particulate matter, but is not intended to include individual dissolved molecules. Specifically, the term particle as used herein includes particulates having on the order of at least 5 nm physical dimension.
  • the particle material comprises an inorganic material, such as an n-type semiconductor having a band gap of at least about 2 eV.
  • the particle material is also preferably photoconductive.
  • Appropriate materials for use in this method include titanium dioxide, zinc oxide, zinc sulfide, and iron oxide.
  • the beads may be made to aggregate organic compounds.
  • the beads do not disperse on an oil layer, but instead form floating clumps made up of bead-oil matrices.
  • the beads may be used in conjunction with microbes that biodegrade organic compounds.
  • oil may be partially photooxidized by the beads, and then microbes may be used to complete the oxidation to carbon dioxide and other less harmful products.
  • the bead surface is optimized to a have a specified amount of coverage by a catalyst. In this manner optimum photoillumination properties may be achieved without use of excess catalyst.
  • the bead will preferably float on the surface of oil.
  • percent of the bead surface area above of the oil-air interface has been optimized.
  • bead densities may be tailored for certain oil densities to achieve the optimum bead surface area above the oil-air interface, and thereby achieve optimum photocatalytic effect.
  • the beads are coated with a catalyst, and a small amount of palladium.
  • the palladium has been found to synergistically work in conjunction with other less expensive catalysts to achieve enhanced photocatalytic effects.
  • Figure 1 is an exterior view of a partially coated bead as provided by a preferred embodiment of the present invention.
  • Figure 2 is a sectional view of the coated bead shown in Figure 1.
  • Figure 3 is an exterior view of another partially coated bead as provided by this invention.
  • Figure 4 is a schematic drawing showing coated beads dispersed in an oil film floating on water, as provided by preferred methods of practicing this invention.
  • Figures 5 and 6 depict chromatograph results for samples of organic compounds that have been treated with certain beads and ultraviolet light.
  • Figures 7-9 depict fluorescence measurements for certain samples that were treated with microbes, beads, and/or light.
  • Figures 10-11 show catalyst distribution and photon flux on a bead on oil.
  • Figure 12 shows light dispersion of oil (A) and fused quartz (B) .
  • Figure 13 shows the refractive indices of aluminosilicate glasses as a function of their relative composition.
  • Figure 14 shows the absorbance of several Middle East Crudes.
  • Figures 15-16 show the absorbed ultraviolet light fraction for various bead surface coverage by titanium dioxide.
  • Figure 17 shows the calculated fraction of the incident solar UV flux absorbed by the titanium dioxide coating as a function of the area of the bead coated by the titanium dioxide coating.
  • Figure 18 shows a hollow glass bead partially covered by titanium dioxide and deeply immersed in oil.
  • Figure 19 shows the absorbed UV fraction for various bead surface coverage by titanium dioxide.
  • Figure 20 shows the calculated fraction of the incident 360 nm solar flux absorbed by the titanium dioxide coating as a function of the index of refraction of the glass of the beads.
  • Figure 21 shows the calculated fraction of the incident 360 nm solar flux absorbed by the titanium dioxide coating as a function of the thickness of the shell of the beads.
  • Figure 22 shows a cell used for methanol oxidation experiments.
  • Figures 23-27 show the transfer current as a function of time for vitreous carbon electrodes using various catalysts at various conditions.
  • Figure 28 shows the effect of palladium incorporation in the titanium crystallites on the rate of HC1 generation through the photoassisted oxidation of sodium 2,2'-dichloropropionate in water.
  • Various embodiments of this invention provide environmentally safe technology for treating crude oil slicks resulting from oil spills, in the form of coated beads or particles designed to float with and photoassist in (i.e. photocatalyze) the oxidation of oil slicks when exposed to sunlight and oxygen dissolved in oil, dissolved in water, or in air.
  • the beads may be used by themselves or with microbes.
  • the beads may be capable of spreading on oil slicks to photocatalyze the oil, or the beads may be capable of forming floating matrixes in which oil is aggregated in the matrix and then photocatalyzed.
  • the beads consist of hollow glass or ceramic microspheres of about 10-30 microns diameter. Beads of this type are manufactured and are commercially available. Their density is about 0.4 g/cm 3 for glass beads and about 0.7-0.8 g/cm 3 for ceramic beads. Microbeads of 10-30 microns diameter are nearly invisible to the human eye, and thus not an eyesore. Larger microbeads could alternatively be used and would typically have the appearance of white sand.
  • Figs. 1 and 2 illustrate a preferred coated bead 10 for use in this invention.
  • Each hollow bead 11 may be coated at random sites with a photocatalytic coating material 12, resulting in a bead with coated areas 13 and uncoated areas 14.
  • the bead may alternatively be fully coated, but is preferably only partially coated so as to save on coating material.
  • sunlight may enter the coated bead 10 through exposed areas 14 and may be waveguided to the coating material 12, as described in more detail below.
  • the term "oxidation material” is defined to mean a material that will enhance or catalyze oxidation reactions.
  • the coating material 12' may be dispersed relatively uniformly on the bead 11'.
  • the coating material 12 comprises Ti0 2 pigment particles having diameter on the order of 30-200 nm.
  • the coated bead 10 is engineered to have a density of around 0.4-0.9 g/cm 3 , and the regions 14 of the bead that are not n-Ti0 2 particle coated are made hydrophobic (i.e. oleophilic) . In use, such coated beads will tend to be attracted to and float with an oil layer.
  • the coated beads may be prepared by starting with commercial hollow glass or ceramic microspheres and depositing on their surfaces a semiconducting photocatalyst by a gas phase process.
  • a gas phase process for example, the
  • 20 surface of the beads may be prepared in a fluidizing bed arrangement by flowing through a stream of dry nitrogen that contains a surface di- or trialkoxy (or chloro) silane. Subsequently, a gaseous dispersion of Ti0 pigment particles may be passed through the bed of
  • oxidation material includes semiconductor materials.
  • the beads may be covered with a semiconductor at least partially coated with palladium.
  • the surface of the ceramic beads may be coated by a smoke of partially hydrolyzed, reactive ⁇ titanium tetrachloride (TiCl or tetraalkoxide(Ti(OR) 4 ) .
  • SiO 2 35 (glass) hydrophobic i.e. oleophilic
  • an oil-wetted coating on the bead such as exposure to trimethyl chlorosilane vapor (e.g. a dry air-stream with trimethyl chlorosilane) .
  • trimethyl chlorosilane vapor e.g. a dry air-stream with trimethyl chlorosilane
  • Only one monolayer is typically needed to make the surface hydrophobic.
  • the partially coated bead 10 may be exposed to such a material to render it substantially hydrophobic.
  • the resulting hydrophobic organic monolayers may be photooxidized on the bead areas 13 coated with n-Ti0 2 particles 12, they will remain on the uncoated glass or ceramic surface 14.
  • the bead 11 surface may first be made hydrophobic, and subsequently partially coated with photocatalytic material 12.
  • a plurality of water floatable, partially coated beads 16 may be dispersed within an oil film 18 on water 20.
  • the beads 16 may be of varying density and degree of hydrophicity, and thus reside at differing depths of the oil film 18, as shown in Fig. 4.
  • the diameter of the beads 16 is preferably less than the thickness of the oil film 18.
  • the critical trapping angles at the air-oil and oil-water interfaces to achieve such propagation are typically about around 46° and 72°, respectively.
  • the coated beads 16 being preferably made of glass or ceramic, have an index of refraction at some or all of their surface of approximately 1.5 or more, which is above that of seawater and oil.
  • incident sunlight represented as dashed lines 24
  • the higher index coated beads 16 by total internal reflection of the light.
  • the index of refraction of Ti0 2 (rutile) is about 2.8 (well above the index of the glass or ceramic)
  • the light may be waveguided to the Ti0 2 coating particles.
  • the effect may be similar to a high index dust particle (analogous to the Ti0 2 on the bead) on an optical fiber (analogous to the oil film) carrying a laser beam (analogous to the reflected sunlight) .
  • both direct and reflected light can reach the photocatalytic coating material on the coated beads 16.
  • Photons of less than 3 eV energy, absorbed by the particles, can produce a flux of oxidizing holes and peroxide forming electrons, thereby accelerating oxidation or organic compounds in the oil film 18.
  • the actual solar radiation collecting area per microbead will typically depend on the extinction coefficient through the 300-400 nm range. Even for highly absorbing oils, the effective collection area per microbead may be greater than approximately 0.01 cm 2 , considerably larger than the actual bead surface area of the smaller beads of this invention.
  • the initial photooxidation products will be slightly water soluble alcohols, ketones, and carboxylic acids. Though not proven to be safe to sealife, these products can be highly diluted as they can dissolve in seawater. Also, the photooxidation products may be far more rapidly attacked by microorganisms (that eventually oxidize them to C0 2 ) than the hydrocarbons of a slick.
  • the diameter of the preferred beads is approximately 10-30 microns, about 6 g of material will cover 1 m 2 of area (this is a conservative estimate, since each microbead may actually collect light from an area that is 10-100 times its own, even in a heavy, strongly absorbing crude, because of the waveguiding properties of the oil film) .
  • the materials cost is approximately 1.3 /m 2 .
  • the corresponding materials cost for cleaning up 1 barrel of oil in one month is thus less than $2.60.
  • coated microbeads provided by this invention may be carried in and dispersed from bulk grain or fertilizer carrying ships, then dispersed on the ocean surface with the oil, by wind and waves. Because the coated beads are preferably hydrophobic and because their density can be adjusted to be somewhat less than that of crude oil, they can follow the slicks, floating near their surface. Their transportation and dispersion costs should be similar to those for bulk free-flowing fertilizers.
  • the materials used for the beads and bead coatings are substantially safe to ingest, and thus will not significantly harm humans, fish, birds or vegetation.
  • the beads may be prepared with mixed Ti0 2 from several sources, as discussed below.
  • a mixture of Ti0 2 was prepared as follows: about 0.64 g of Degussa Corporation brand P25 Ti0 2 was mixed with about 2.56 g Hombitan brand Ti0 2 (Sachtlebenchemie GMBH, Duisburg-Homberg, Germany) and 1.68 g SLG (PQ Corporation) brand beads.
  • the SLG brand beads are alumino silicate beads.
  • the total Ti0 2 weight percent was about 16 %, of which about 3.2 % was the Degussa P25 Ti0 2 , and about 12.8% was the Hombitan Ti0 2 .
  • the Degussa Ti0 2 tended to be smaller than the Hombitan.
  • the Degussa was used to "cement" Hombitan to the beads, since the Hombitan was more difficult to adhere to the beads. In this manner the larger Hombitan crystals were attached to the beads, which tended to improve the amount of Ti0 2 on the bead surface.
  • the Degussa and Hombitan was generally mixed together first, and then the beads were carefully added. After preparing the Ti0 2 mixture, as small amount as possible of nano(i.e. , deionized) water was added to make a thick slurry. The mixture was then stirred gently and sonicated for about 5 minutes. The sonicating bath was a vibrating bath which operated at high frequency to enhance mixing, as is well known in the art.
  • the mixture was then dried in the oven at 120° for about 1 hr. After drying the remaining beads were calcined (in an ambient atmosphere) in a furnace at about 750°C for about 1 hour. The beads were then cooled.
  • the beads were contacted (etched) with boiling 0.1M HC1 for about 10 min.
  • the beads were then washed in nano water in a microanalysis separator (i.e., usually a funnel or highly porous filter paper).
  • the beads were then dried in a oven at about 110°C. It is estimated that about 8.3 weight percent of the resulting beads was Ti0 2 .
  • the beads of the invention may be made so that they include a nonporous shell onto which the coating material may be coated.
  • the shell may be non-gas permeable, and may enclose a gas-filled or evacuated core.
  • floatable beads or particles may be made so that they do not tend to disperse or float with the oil individually. Instead these beads or particles are capable of forming matrices which aggregate the oil.
  • the beads that aggregate have surfaces modified with oleophilic 3-dimensional matrices of 100 to 5000 Angstrom thickness.
  • the oil is soaked into the matrices and the oil in the matrices may stick to itself, thereby causing the beads to stick to each other, and to other beads coated with oil.
  • the beads may form pores between the beads because, among other possible reasons, the beads are made with an enhanced oleophilic surface.
  • the enhanced oleophilic surface causes the beads to stick to the oil, and each other (the beads tend to be attracted to other beads that are coated with oil) .
  • pores may be formed between the beads.
  • the matrices are then believed to aggregate oil due to capillary forces acting on the oil when the oil is contacted with the matrices.
  • the surface of the beads has been modified such that the beads may form oleogel structures which enhance attraction of the oil.
  • one embodiment of the invention includes water floatable beads that have an equivalent diameter of less than about 2 mm, wherein the beads have an exterior surface which is at least partially coated with a material that under illumination and in the presence of air is capable of accelerating the oxidation of organic compounds floating on water, and wherein the beads are capable of aggregating organic compounds during use.
  • the beads may be at least partially coated with an organosilicate network. This network may include a series of organosilicon oxide crosslinking.
  • the beads that may enable them to aggregate oil is highly oleophilic nature of the coating on the beads.
  • This oleophilic coating is provided by alkyl groups (e.g., methyl groups) bonded to crosslinked silicon atoms on the surface of the beads.
  • the highly oleophilic nature of the beads may be quantified in that the beads are capable of forming less than a fifteen degree contact angle, as defined by the Young equation, when contacted with a substantially water-insoluble organic compound.
  • the beads are capable of forming approximately a 0-10 degree contact angle, more preferably a 0-5 degree contact angle, and more preferably still a 0-2 degree contact angle, as defined by the Young equation, when contacted with a substantially water-insoluble organic compound.
  • the beads of the invention are believed to be covered by a crosslinked network which creates small discontinuities on the bead surface. These discontinuities are believed to contribute to the aggregation of the organic compounds via capillary action. These discontinuities may include pores or crevasses, however these pores are believed to be much smaller than pores that are created on glass by standard procedures. The pores in the discontinuities of the present invention are believed to be about 10-100 Angstroms in size.
  • the beads of the invention are capable of aggregating substantial amounts of organic compounds. For instance, preferably about 0.5 to 2.0 grams of beads are capable of aggregating about 1.0 gram of organic compound. It has been found that the beads may aggregate at least about 50 percent of their weight of oil in less than about five minutes.
  • the beads of the invention may be capable of spontaneously aggregating oil or other non-crystalline organic compounds.
  • the beads of the invention may be used for extracting organic compounds mixed in water (i.e., not just on the surface) by dispersing the beads in the water, preferably with stirring.
  • the aggregation beads of the invention may aggegate organic compounds in the water and then float to the surface, thereby removing organic compounds from the water.
  • the surface of the beads may be preferentially coated with certain percentages of the coating material (see collection optics discussion below) .
  • an optimal amount of the bead may be exposed to the air at the bead-air interface (see collection optics discussion below) .
  • light utilization, refraction and reflection within the bead may be optimized.
  • approximately 45-90 percent, more preferably 50-75 percent, of the exterior surface of each bead is exposed to air when the beads are floated on organic compounds during use.
  • the organic compounds tend to form matrices that may be left in the water to photooxidize by exposure to additional solar illumination and ambient air.
  • These matrices i.e., oil-bead clumps
  • These matrices may then be left in the water to photooxidize, or they may be collected and brought on ships or land, and then exposed to solar illumination and ambient air. Alternately, oil-bead matrices may be allowed to wash ashore, and then photooxidize on land.
  • the beads may be used with a microbe that is capable of biodegradmg at least one organic compound in the oil film (see microbe discussion below) .
  • the aggregation beads may be made by mixing an organosilicate with the beads; adding the coating material to the mixture; and then heating the mixture. Less than a stoichiometric amount of water (preferably about 0.3 to less than 1.0, more preferably about 0.4- 0.6) may be added to the organosilicate before mixing with the beads.
  • the organosilicate and water mixture is heated and refluxed before mixing with the beads.
  • the organosilicate and bead mixture may be heated and refluxed before adding the coating material.
  • the organosilicate used above may be a composition which includes a compound or compounds according to the formula:
  • R is an alkyl, alkoxy, hydroxide, or hydrogen group, and wherein the average ratio of alkyl groups to silicon groups in the composition is greater than or equal to one, and less than two, and wherein the average ratio of alkoxy groups to silicon groups in the composition is greater than two, and less than or equal to three.
  • the alkyl groups are methyl groups
  • the alkoxy groups are methoxy groups.
  • the organosilicate include methyltrimethoxysilane.
  • the organosilicate may also be a mixture of any or all of methyltrimethoxysilane, tetramethoxysilane, or dimethydimethoxysilane.
  • One method of preparing beads that aggregate oil included the following steps:
  • Degussa P-25 Ti0 2 (Degussa Corp., North Dublin, Ohio, U.S.A.) was then added slowly and carefully to the flask. Degussa P-25 is believed to be a mixture of approximately one-third rutile and approximately two-thirds anatase. The mixture was then refluxed for about 2 hours.
  • the beads were then heated in an oven at about 200°C, and then water washed until a clear solution obtained.
  • the beads were then etched once dilute 0.1 Molar HC1.
  • the beads were then washed in a 2,000 ml separatory funnel 10-20 times with 750-1000 ml nano water. When the water in the funnel remained clear, the beads were then again etched in dilute HC1 and then rewashed with nano-pure water about 3-5 times.
  • Beads prepared by the above procedure tended to have at least a 2-3% quantum efficiency (i.e., percent of photons that photoinduce a reaction) in the conversion of 3-octanol to 3-octanone.
  • This quantum efficiency may be roughly doubled if the beads are slightly reduced (i.e., placed in a hydrogen stream at about 450°C for about 1 hour and 15 minutes) .
  • the activity may be further enhanced if the Ti0 2 is then coated with a small amount of palladium.
  • the bonding of Ti0 2 particles to the SLG beads using methyltrimethoxy silane as a coupling agent is a three step process, as discussed below.
  • the reactions are carried out in a batch reactor held at about 78°C (which is the approximate boiling point of the solvent) .
  • the first step involves the partial polymerization reaction of methoxy units to form, primarily, chains of a polysiloxene gel.
  • a substoichlometric amount of water is added that, at an acidic pH, polymerizes the MTMOS into a sol network still having reactive methoxy groups. Only a small amount of the MTMOS monomer is actually polymerized.
  • the stoichiometry of the reaction may be:
  • the SLG microspheres are then added to the solution.
  • the surface pH of the beads is about 5.8, the pH of the solvent is about 3-3.5. Moisture on the bead surface may cause the sol in the solution to react with the bead surface. The surface thus becomes covered with the partially polymerized sol.
  • Ethanol was used as a solvent. Other solvents could be used such as alkanes (e.g., hexane). Ethanol was chosen because of its low cost and toxicity. It is believed to be important that an excessive amount of water is not added to the reaction. Otherwise, the reaction may progress to complete polymerization. In other words, a small amount of water may partially crosslink the MTMOS, but not totally react or polymerize the MTMOS. Thus available methoxy groups for further reaction may remain after the water is added, as discussed above.
  • Titanium dioxide particles are added to the silica sol SLG/solvent solution.
  • the pH of the titania, Degussa P-25, is about 4.2.
  • the hydrated Ti0 2 particle surface may then be reacted with unreacted methoxy groups.
  • the Ti0 2 particles begin to bond to the bead through reaction of the remaining methoxy groups in the sol layer with the Ti0 2 surface.
  • pH of the bead may affect attachment of Ti0 2 and MTMOS to the bead.
  • the solution is finally filtered, and allowed to dry and cure.
  • the Ti0 2 particles are bonded to the SLG (PQ Corporation) bead.
  • the procedure results in bonding to the surface of the SLG beads of a matrix containing photoactive titania.
  • the surface of the matrix is made oleophilic by the polymer's alkyl units.
  • the excess Ti0 2 is removed by repeated washing in water and one wash in dilute HC1.
  • Beads prepared by this procedure have a titania (“Ti0 2 ”) loading of 5 to 15+ wt% Ti0 2 , depending on the amounts of the reagents and titania used.
  • Ti0 2 titania
  • the coating is stable under uv exposure for several weeks, and the beads are photoactive in the conversion of 3-octanol to 3- octanone.
  • Primary quantum efficiencies are Ti0 2 loading dependent and are typically of 1-4.5%.
  • Surface area of the beads prior to their modification is about 0.1 m 2 per gram.
  • the above method causes the area of the beads to be about 6 m 2 per gram. This surface area was measured by BET nitrogen adsorption. The surface area tends to increase as the amount of Ti0 2 increases.
  • the beads of the invention may include a hermetically sealed glass enclosed bubble that may be evacuated or contain a gas.
  • a hermetically sealed glass enclosed bubble that may be evacuated or contain a gas.
  • at least one surface of the beads is substantially smooth, and thus the beads are substantially nonporous.
  • the smooth surface of the beads is coated with an aleophilic matrix that is 100-5000 Angstroms thick.
  • the microbeads may be used with microbes to enhance oxidation and/or biodegradation of organic compounds.
  • microbes are well known in the art, and the following is a brief discussion of some of these microbes.
  • Hydrocarbon degradation by microbe communities usually depends on the composition of the community and its adaptive response to the presence of hydrocarbons.
  • Bacteria and fungi are agents of degradation, with bacteria tending to assume the dominant role in marine ecosystems and fungi becoming more important in freshwater and terrestrial environments.
  • Adapted communities i.e., those which have been previously exposed to hydrocarbons, exhibit higher biodegradation rates than communities with no history of hydrocarbon contamination.
  • Individual organisms may metabolize only a limited range of hydrocarbon substrates, so that mixed populations with overall broad enzymatic capacities may be preferred to degrade complex mixtures of hydrocarbons such as crude oil in soil, freshwater, and marine environments.
  • Preferred hydrocarbon-degrading bacteria in marine environments include Achromobacter, Acinetobacter,
  • Fungi tend to be relatively minor components of the marine microflora, increasing in numbers in nearshore regions, the intertidal zone, and salt marshes and mangrove areas. Fungi are important inhabitants of specialized niches such as submerged wood, the surface film of water, decomposing algae, and the surface of tarballs.
  • a hydrocarbon-degrading fungus, Cladosporium resinae tends to degrade petroleum if added as an inoculum.
  • Seeding involves the introduction of allochthonous microbes into the natural environment for the purpose of increasing the rate or extent of biodegradation of pollutants.
  • the criteria to be met by effective seed microbes include the ability to degrade most petroleum components, genetic stability, viability during storage, rapid growth following storage, a high degree of enzymatic activity and growth in the environment, the ability to compete with indigenous microbes, nonpathogenicity, and the inability to produce toxic metabolites.
  • Mixed cultures have been used as inocula for seeding because of the relative ease with which microbes with different and complementary hydrocarbon- degrading capabilities may be isolated. Seed microbes may be chosen from those genera listed in Table 1.
  • microbial strains have been constructed through genetic manipulation which are able to degrade a variety of different types of hydrocarbons.
  • a multiplasmid- containing Pseudomonas strain capable of oxidizing aliphatic, aromatic, terpenic, and polyaromatic hydrocarbons may be constructed.
  • Such recombinant microbes may be well suited as seeding organisms for the degradation of oil spills.
  • Beads may be reduced to increase the quantum efficiency of their photocatalytic activity. For instance, beads prepared according to Example 2 above were reduced in a stream of H2 (100 cm 3 of H 2 per minute) at 450°C for 2.5 hours and cooled down to room temperature under a stream of H 2 .
  • the Ti0 2 on the beads may be partially coated with palladium to increase the quantum efficiency.
  • One method used to coat the beads is discussed below.
  • a first solution was prepared by dissolving 0.011 g of PdS04 in 50 ml of nano water with 3 to 4 drops of concentrated HC1. Five ml of this solution was mixed with 3 g of beads prepared according to Example 2 above, 2.5 ml of glacial acetic acid, and 200 ml of nano water. This mixture was then put under UV radiation (6mW/cm 2 ) with N 2 bubbling through it for about 20 hrs. The beads were then filtered, washed and dried.
  • Beads were prepared according to example 2 above and then reduced at 450 C for 2.5 hours, and then coated with palladium, according to example 6 above, so that about 1.2 weight percent of the beads was palladium.
  • Reactor vessels were prepared that had a constant flowthrough of oxygen during photooxidation.
  • Various crude oil samples as outlined below, were illuminated with ultraviolet light for 65 hours. After 65 hours, photooxidation was stopped and the crude oil fractions collected and dissolved in 5 ml of hexane. Components of each sample are given below and were added in the order given.
  • the toluene was added to help spread the heavier crude oil on the water. After photocatalytic oxidation of the samples, they were analyzed using a high performance liquid chromatograph system ("HPLC" system) . The procedure for analysis was as follows:
  • a NH 2 Sep-Pak cartridge (Waters Chromatography, U.S.A.) was prepared by flushing the cartridge with 5 ml of hexane.
  • the X axis represents time, in minutes.
  • the samples with the beads (samples 1 in Figures 5-6) exhibited substantially lower amounts of the crude oil components than the samples that did not have beads in them.
  • Some of the peaks for the samples with beads were different than the peaks for the samples without beads, indicating that photooxidation is breaking the crude oil samples into different compounds.
  • photocatalytic oxidation converts the primarily non-polar components of the oil to polar that are not eluted from the adsorption column.
  • Figures 5-6 show that 50-80% of the various organic compounds was oxidized.
  • Beads means beads without a coating material were added to the sample.
  • bearings/catalyst means beads prepared according to Example 2 were added to the sample.
  • MTMOS beads means beads prepared according to Example 3 were added to the sample. The components of the systems were placed in the covered crystallization dishes in the following sequence.
  • the water with fertilizer is made by dropping 7 drops of "Schultz-Instant" plant food in 1 liter of nano water.
  • the plant food is believed to include nitrogen, phosphorous, and potassium.
  • microbe culture 0.5 ml of a mixed culture from Oppenheimer (Austin, Texas, U.S.A.). The culture contents was not disclosed by Oppenheimer. Beads/catalyst - 2g
  • Crude oil means oil was in the sample.
  • UV radiation means that the samples were irradiated with UV light, as discussed above.
  • Turbidity increase in the water layer was observed to be greatest in the samples with beads proposed according to Examples 2 and 3 above.
  • the microbeads of the invention have a specified amount of their exterior surface covered with catalyst.
  • the beads may be designed so that a certain percentage of the beads extends above the oil-air interface. Both the amount of surface coverage and bead extension above the interface may be optimized to enhance light collection optics of the beads.
  • the optics of the system is analyzed. The procedures and results of this analysis are presented below.
  • an electron-hole pair may be generated in the Ti0 2 microcrystal.
  • the electron may react with surface-adsorbed oxygen, reducing it to hydrogen peroxide.
  • the hole may oxidize adsorbed water to OH radicals and photons, and the OH radicals may oxidize in turn adsorbed organic compounds.
  • the electrons react with oxygen and protons to produce hydrogen peroxide.
  • Titanium dioxide is denser than either oil or seawater.
  • the density of anatase is 3.8, and that of rutile is 4.3.
  • Collection optics depends on the complex refractive indices of the glass, of the Ti0 2 , and of the oil in the UV band of interest—that is, 350-360 nm.
  • the aluminosilicate glasses used may have real indices ranging from 1.48 to 1.73 at 350 nm.
  • Both the literature and experimental measurements show that crude oils adsorb strongly in the UV.
  • the absorbencies of three crude oils (Arab light, Arab heavy, Basrah light) at 350 nm ranged between 1.5-3.0x10* cm "1 .
  • a 2 ⁇ n thick layer of one of these crudes adsorbs 95% of the solar UV flux at 350-360 nm. Therefore, it is preferred that the hollow glass beads have sufficiently low density to float on the surface at the air/oil interface, and are sufficiently buoyant so that less than one-half of the bead is submerged in the oil.
  • the hollow beads were considered to be of arbitrary diameter with shells made of perfectly transparent aluminosilicate glass and a shell thickness about 10% of the diameter.
  • the depth of immersion of a bead in an oil slick depends on the viscosity of the oil and its surface properties (which both vary with age of slick, temperature, etc.) as well as on the density of the bead itself. Therefore, for the initial estimate it is assumed that the bead is floating as shown in Figure 10. In Figure 10 the depth of immersion was about 15% of the external diameter of the bead.
  • the incoming radiation was taken to be of unit intensity at 360 nm and made an angle of 45 degrees with the surface.
  • the photon flux adsorbed by the Ti0 2 particles has two components, an outer and inner flux, as indicated by Fig. 10.
  • the outer flux involves absorption of solar photons that only pass through the atmosphere, for example Ray A, Fig. 11.
  • the inner flux is composed of photons refracted into the bead at the air-glass interface and are subsequently absorbed by the attached Ti0 2 , for example Ray B or Ray C, Fig. 11.
  • the collection of sunlight is analyzed for beads at varying photocatalyst coverages and varying immersion in the strongly UV light-absorbing crudes. Theory
  • An angular absorption function (AAF) was introduced that relates the absorbed light with the Ti0 2 monocrystal layer's "center" polar angle A(#) for a layer of area S. Assuming that occupation of all positions on the bead's surface by the Ti0 2 layer have uniform probabilities, we can consider an angle-averaged absorption A av by a Ti0 2 crystalline layer (regardless of its position on the glass bead) can be considered to only depend for optically thick crystallites on the covered area T of the bead. This is:
  • A(T, ⁇ ) is the amount of energy absorbed by a Ti0 2 layer of area T with its center at the polar angle ⁇ .
  • u,v are the current coordinates of the microbead surface and dS is a surface element.
  • Index of refraction refers only to its real part. For silica glass and oil the variation in the indices with wavelength, i.e., dispersion in the near UV does not exceed 1% (Fig. 12).
  • the Y-axis is the index of refraction and the X-axis is the wavelength in ⁇ M.
  • the curve is the dispersion of oil (Curve A) and fused quartz (Curve B) .
  • the index of aluminosilicate glasses (A1203-Si0 2 ) depends strongly on their alumina content (Fig. 13).
  • the Y-axis is the index of refraction and the X-axis is the composition (mole % of A1 2 0 3 ) .
  • any Ti0 2 monocrystallite layer is considered to be continuous, having boundaries that are parallel to the surface of the bead, and thick enough to absorb all of the photons with energies exceeding the band-gap. Provided the bead density is much less than the density of the oil, the beads are floating on the surface as shown in Fig. 10.
  • Fig. 14 shows that the UV light is strongly absorbed by the crudes.
  • Curve A represents Basrah light
  • Curve B is Arab light
  • Curve C is Arab heavy.
  • Y-axis is the absorbance, in ⁇ M "1
  • the X-axis is the UV wavelength in ⁇ M.
  • the AAF of the bead totally covered by Ti0 2 is a perfect circle (a perfect sphere in three dimensions) .
  • A,. v 0.65
  • absorption is independent of the optical properties of the glass bead.
  • a microbead is almost totally immersed in an oil layer, as shown in Fig. 18.
  • most of the attached photocatalyst is immersed in the highly absorbing crude oil layer.
  • the AAFs shown in Fig. 15 for a microbead with most of its surface above the oil layer change to those shown in Fig. 19 for the nearly submerged microbead.
  • the AAFs become more stretched and decrease in value because the incident flux pencil is narrowed. They are less symmetrical with respect to the incident flux direction because the whole optical system becomes less symmetrical.
  • Corresponding values of average absorption are shown in the same figure.
  • the effectiveness of the photocatalyst layer for this case is shown in Fig. 17(B).
  • the microbeads of the invention may be at least partially coated with a semiconductor the surface of which is coated palladium.
  • This system under illumination and in the presence of air, is capable of accelerating the oxidation of organic compounds floating on water.
  • the coating material may include approximately 0.001 to 3.0 weight percent palladium in the semiconducting catalyst (e.g. the Ti0 2 ) , more preferably approximately 0.01 to 0.5 weight percent palladium.
  • the catalytic reaction of organic compounds on water is believed to involve oxidation of surface-adsorbed water by holes to produce OH radicals that oxidize organic compounds. This reaction is believed to be coupled with reduction of dissolved 0 2 , initially to peroxide and then ultimately to water.
  • the rate of the hole initiated oxidation may be fast, but it may not be faster than the rate of 0 2 reduction by electrons.
  • 0 2 is not reduced at a high enough rate, electrons tend to accumulate on the photocatalyst and the rate of radiationless electron-hole recombination is enhanced until the sum of the rates of recombination and electron transfer to oxygen tends to equal the rate of photogeneration of holes.
  • the rate of photooxidation may equal, and be limited by, the rate of 0 2 reduction.
  • the cell used for the methanol experiments had two compartments separated by a fine glass frit. The cell was designed so that the particles in the slurry, illuminated at the window in the front of one compartment, had to travel for >l ⁇ and cover distance of -2cm in order to discharge their excess charge at a vitreous carbon electrode in the back of the same compartment, where the UV flux was negligible. Vitreous carbon was chosen for charge collection because of its inertness in both oxidation of methanol and reduction of oxygen or water in the potential range where Ti0 2 particles can exchange electrons with it.
  • the charge-collecting glassy carbon electrode (Atomergic, N.Y., U.S.A.) was of 0.3cm diameter and 0.65cm length. Contact to it was made with a silver epoxy to a copper wire.
  • the Ag/AgCl electrode in the second compartment consisted of a 0.1cm thick 1x2cm silver foil. Before each measurement the Ag/AgCl electrode was cleaned in concentrated NH40H, reanodized in 1M HC1 and its -(0.040 - 0.045)V potential vs. SCE
  • the Ti0 2 slurry in the illuminated compartment was magnetically stirred and purged with N 2 (99.9%), 0 2 (99.9%) or air for 30 min. before each measurement.
  • the slurry consisted of 5mg of the Ti0 2 or Pd/Ti0 2 , 75mL of water or an NaCl solution in water and 5mL of methanol. Prior to introduction into the test chamber, 40mL of the slurry was sonicated for 5 min. These 40mL were poured into the illuminated compartment, while the remaining 35mL were poured into the second compartment, containing the Ag/AgCl electrode.
  • the area of the Pyrex window through which the cell was illuminated was 3.75cm 2 and the UV ( ⁇ ⁇ 400nm) irradiance on the window was 0.5mWcm "2 corresponding, for 3.5eV photons, to 5.3xl0 "6 einsteins cm “2 h _1 and for the 3.75cm 2 window to 2xl0" s einsteins h "1 .
  • the electronics consisted of a regulated power supply (Lambda Electronics, Melville, N.Y., U.S.A.), mercury batteries (2.3V) with a homemade voltage divider, a Keithley 614 electrometer, and a Kipp and Zonen BD91 XYY't recorder.
  • the second cell in which the experiments with sodium dichloropropionate were performed, was a 2.5x2.5x5cm Pyrex cuvette with an attached lOOmL bulb containing 0 2 , N 2 or air and magnetic stirring.
  • the UV ( ⁇ ⁇ 400nm) irradiance on the 2.5x5cm face was 50mWcm ⁇ 2 , corresponding for 3.5eV photons face was 5.3x10"* einsteins cm “2 !! "1 , and the total flux on the 12.5cm 2 illuminated face was 6.7xl0' 3 einsteins h" 1 .
  • the slurry for the measurement of the rate of photodegradation of sodium 2,2'-dichloropropionate (10" 2 M in water) consisted of 150mg Ti0 2 or Pd/Ti0 2 suspended in 30mL of water. The 0 2 pressure was maintained near 1 atm. The entire UV flux was absorbed, i.e., the UV flux at the back of the cell was close to nil.
  • the Ti0 2 used was a sample of Hombitan" from Sachtleben, Hamburg, Germany. The material of 0.1-0.3 ⁇ m particle size and anatase phase was calcined prior to use in air at 500°C.
  • the 3 wt% Pd/Ti0 2 samples were prepared by photoelectrodepositing Pd on the Ti0 2 particles in an aqueous slurry (20mL) containing PdCl 2 (25mg) , Ti0 2 (0.5g) and glacial acetic acid (lmL) . Following sonication, the suspension was stirred under UV illumination for 5h.
  • the photoelectrodeposition process involved photoassisted oxidation of acetic acid coupled with reduction of Pd 2+ to Pd°, a possible net reaction being.
  • the bluish black Pd/Ti0 2 powder was thoroughly washed with deionized water, filtered and dried at 120°C.
  • the particle transit time determined by the rotation rate of the magnetic stirrer, is greater than Is. Therefore, the only charge on the particles that is observed is the charge that is not rapidly dissipated by oxidation or reduction of solution components, i.e., only long-lived electrons or holes on the particles are observed.
  • the counter/reference Ag/AgCl electrode was located in a compartment separated from the illuminated one by a frit through which Ti0 2 particles could not pass. Thus, the counterelectrode reaction did not interfere with the observations of the charge of the particles in the illuminated compartment.
  • Figure 23 shows the current collected at the vitreous carbon electrode when maintained at +0.35V vs. Ag/AgCl. That at this potential the Ti0 2 particles are neither reduced nor oxidized in the dark is seen in Figure 25. At a potential of 0.25V vs. Ag/AgCl (Fig. 24) the Ti0 2 particles are still substantially reduced in the dark, i.e. electrons are transferred from the particles to the electrode. There is no such transfer at +0.35V vs. Ag/AgCl (Fig. 25).
  • Figure 23 one . observes under an N 2 atmosphere a substantial current when the light is on. This current is again associated with electron transfer from the Ti0 2 particles to the electrode.
  • the number of photons, x can be l or 2, depending on whether (a) each of the two oxidation steps requires a photon or (b) the second step occurs spontaneously, resulting from injection of an electron into the semiconductor, i.e. involving (photocurrent doubling, well known in the photooxidation of some organic molecules on semiconductors, including Ti0 2 .
  • the possible reaction sequences (eq. 4-7) are the following;
  • Step (6a) may include the following individual reactions:
  • the highest primary quantum efficiency obtained in our experiments is 0.72. Losses are caused by recombination at the surface and at the metal particles, as well as by reverse reactions of electrons with »OH radicals.
  • the catalytic or quantum efficiency of photoassisted oxidation is increased by Pd deposits on the Ti0 2 particles by a factor of 7 at a Pd content of 2%. The efficiency decreases at higher Pd loadings.
  • FIGURE 22 Cell used for measuring the residual charge on slurried Ti0 2 and Pd activated Ti0 2 particles following illumination. Because the illuminated compartment contains an optically dense Ti0 2 slurry, the particles are excited only near the window. The glassy carbon electrode in the dark back of the illuminated compartment measures the charge of the particles after they traverse the ⁇ 2cm front to back distance.
  • FIGURE 23 Delayed charge collection currents from slurried Ti0 2 particles following their illumination in 1.6M aqueous methanol solutions saturated with nitrogen, air or oxygen.
  • the collecting electrode was maintained at +0.35V vs. Ag/AgCl 2 , where as shown in Figure 25, uncharged Ti0 2 particles neither gain nor lose electrons.
  • FIGURE 24 Delayed charge collection currents from slurried Ti0 2 particles in nitrogen saturated, 1.6M aqueous methanol at Figure 24 +0.25V and at Figure 25 +0.35V vs. Ag/AgCl. Note that following their illumination the particles are oxidized, i.e. lose electrons at either potential. However, at 0.25V the particles pick up electrons from the electrode while at +0.35V they do not.
  • FIGURE 26 Palladium catalysis of the depolarization of the slurried Ti0 2 particles by dissolved oxygen. Delayed charge collection currents, following illumination of the particles, are shown for Pd (3% Wt) coated Ti0 2 particles in nitrogen saturated 1.6M methanol, 0.3M NaCl (left) and in the same 0 2 saturated solution, (right) .
  • the charge collecting electrode potential is +0.35V vs. Ag/AgCl.
  • FIGURE 27 Dependence of the delayed charge collection current from slurried bare Ti0 2 particles on the solution-saturating gas in 1.6M aqueous methanol at 0.3M NaCl (top) and at 3.0M NaCl (bottom).
  • FIGURE 28 Co-catalysis of the photoassisted oxidation of lO M sodium 2,2'-dichloropropionate: dependence of the rate of HCl generation on the Pd loading of the Ti0 2 particles.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Microbiology (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Health & Medical Sciences (AREA)
  • Catalysts (AREA)
  • Physical Water Treatments (AREA)

Abstract

On décrit une perle (16) présentant une surface externe qui est au moins partiellement recouverte d'une matière qui, lorsqu'elle est éclairée (24) et en présence d'air (22), peut accélérer l'oxydation de composés organiques, tels que le pétrole (18) flottant à la surface de l'eau, par exemple l'eau de mer (20). La perle (16) flotte à la surface de l'eau et présente un diamètre équivalent inférieur à 2 mm, de préférence de l'ordre de 10 à 200 microns. Ces perles revêtues peuvent être utilisées pour accélérer sous l'effet de la lumière (24) l'oxydation d'une pellicule de pétrole flottante (18) (provenant par exemple d'une fuite de pétrole). On disperse à cet effet les perles revêtues (16) dans la pellicule afin qu'elles soient exposées à la lumière solaire et à l'oxygène. On peut utiliser des variantes de ces perles avec des micro-organismes qui dégradent le pétrole, ou pour provoquer l'agrégation du pétrole.
PCT/US1992/001790 1992-03-05 1992-03-05 Matieres et procedes permettant la photocatalyse amelioree de composes organiques WO1993017971A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU23216/92A AU2321692A (en) 1992-03-05 1992-03-05 Materials and methods for enhanced photocatalyzation of organic compounds
PCT/US1992/001790 WO1993017971A1 (fr) 1992-03-05 1992-03-05 Matieres et procedes permettant la photocatalyse amelioree de composes organiques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1992/001790 WO1993017971A1 (fr) 1992-03-05 1992-03-05 Matieres et procedes permettant la photocatalyse amelioree de composes organiques

Publications (1)

Publication Number Publication Date
WO1993017971A1 true WO1993017971A1 (fr) 1993-09-16

Family

ID=22230862

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/001790 WO1993017971A1 (fr) 1992-03-05 1992-03-05 Matieres et procedes permettant la photocatalyse amelioree de composes organiques

Country Status (2)

Country Link
AU (1) AU2321692A (fr)
WO (1) WO1993017971A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5616532A (en) * 1990-12-14 1997-04-01 E. Heller & Company Photocatalyst-binder compositions
US5849200A (en) * 1993-10-26 1998-12-15 E. Heller & Company Photocatalyst-binder compositions
GB2327082A (en) * 1997-04-01 1999-01-13 Doryokuro Kakunenryo Disposing of waste oil by sorption
GB2346140A (en) * 1997-04-01 2000-08-02 Doryokuro Kakunenryo Disposal method for fuel oil and crude oil spills
US6498000B2 (en) 1993-06-28 2002-12-24 Ishihara Sangyo Kaisha, Ltd. Photocatalyst composite and process for producing the same
RU2232806C2 (ru) * 2002-08-12 2004-07-20 Институт биологии Уфимского научного центра РАН Консорциум штаммов микроорганизмов bacillus brevis и arthrobacter species, используемый для очистки воды и почвы от нефти и нефтепродуктов
EP2573164A1 (fr) * 2011-09-23 2013-03-27 Green C GmbH Procédé de décomposition microbiologique d'hydrocarbures
WO2017114918A1 (fr) * 2015-12-30 2017-07-06 Koninklijke Philips N.V. Appareil d'oxydation photocatalytique
WO2018106791A1 (fr) * 2016-12-06 2018-06-14 University Of South Carolina Amélioration de la toxicité du mazout et stimulation de l'assimilation de mazout par des bactéries
CN109607829A (zh) * 2019-02-21 2019-04-12 清华大学 一种黑臭水体修复药剂及其制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3562153A (en) * 1970-02-05 1971-02-09 Cabot Corp Oil absorbent compositions
US4863608A (en) * 1986-02-20 1989-09-05 Nomura Micro Science Co., Ltd. Photocatalytic treatment of water for the preparation of ultra pure water

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3562153A (en) * 1970-02-05 1971-02-09 Cabot Corp Oil absorbent compositions
US4863608A (en) * 1986-02-20 1989-09-05 Nomura Micro Science Co., Ltd. Photocatalytic treatment of water for the preparation of ultra pure water

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ENVIRON. SCI. TECHNOL., Vol. 19, No. 7, 1985, J.R. PAYNE AND C.R. PHILIPS, "Photochemistry of Petroleum in Water", pages 569-579. *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5616532A (en) * 1990-12-14 1997-04-01 E. Heller & Company Photocatalyst-binder compositions
US6498000B2 (en) 1993-06-28 2002-12-24 Ishihara Sangyo Kaisha, Ltd. Photocatalyst composite and process for producing the same
US6093676A (en) * 1993-10-26 2000-07-25 E. Heller & Company Photocatalyst-binder compositions
US5849200A (en) * 1993-10-26 1998-12-15 E. Heller & Company Photocatalyst-binder compositions
US5854169A (en) * 1993-10-26 1998-12-29 E. Heller & Company Photocatalyst-binder compositions
US6030536A (en) * 1997-04-01 2000-02-29 Japan Cycle Nuclear Development Institute Disposal method for fuel oil and crude oil spills
GB2346140A (en) * 1997-04-01 2000-08-02 Doryokuro Kakunenryo Disposal method for fuel oil and crude oil spills
GB2327082B (en) * 1997-04-01 2001-06-06 Doryokuro Kakunenryo Disposal method for fuel oil and crude oil spills
GB2327082A (en) * 1997-04-01 1999-01-13 Doryokuro Kakunenryo Disposing of waste oil by sorption
RU2232806C2 (ru) * 2002-08-12 2004-07-20 Институт биологии Уфимского научного центра РАН Консорциум штаммов микроорганизмов bacillus brevis и arthrobacter species, используемый для очистки воды и почвы от нефти и нефтепродуктов
EP2573164A1 (fr) * 2011-09-23 2013-03-27 Green C GmbH Procédé de décomposition microbiologique d'hydrocarbures
WO2017114918A1 (fr) * 2015-12-30 2017-07-06 Koninklijke Philips N.V. Appareil d'oxydation photocatalytique
WO2018106791A1 (fr) * 2016-12-06 2018-06-14 University Of South Carolina Amélioration de la toxicité du mazout et stimulation de l'assimilation de mazout par des bactéries
US11814308B2 (en) * 2016-12-06 2023-11-14 University Of South Carolina Nanoparticles for the amelioration of oil toxicity and stimulation of bacterial oil degradation
US12103880B2 (en) 2016-12-06 2024-10-01 University Of South Caroina Methods for the amelioration of oil toxicity and stimulation of bacterial oil degradation
CN109607829A (zh) * 2019-02-21 2019-04-12 清华大学 一种黑臭水体修复药剂及其制备方法

Also Published As

Publication number Publication date
AU2321692A (en) 1993-10-05

Similar Documents

Publication Publication Date Title
AU657470B2 (en) Materials and methods for photocatalyzing oxidation of organic compounds on water
US5256616A (en) Materials and methods for photocatalyzing oxidation of organic compounds on water
Md Rosli et al. Photocatalytic Performance of ZnO/g-C 3 N 4 for Removal of Phenol under Simulated Sunlight Irradiation
Nair et al. Rates of photocatalytic oxidation of crude oil on salt water on buoyant, cenosphere-attached titanium dioxide
Divya et al. Photocatalytic degradation of azo dye Orange II in aqueous solutions using copper-impregnated titania
Shon et al. Visible light responsive titanium dioxide (TiO 2)
Sienkiewicz et al. Effect of calcination on the photocatalytic activity and stability of TiO2 photocatalysts modified with APTES
Hariprasad et al. Sunlight induced removal of Rhodamine B from water through semiconductor photocatalysis: effects of adsorption, reaction conditions and additives
Sboui et al. TiO2/Ag2O immobilized on cellulose paper: A new floating system for enhanced photocatalytic and antibacterial activities
US10413888B2 (en) Iron doped titanium dioxide nanocrystals and their use as photocatalysts
WO1993017971A1 (fr) Matieres et procedes permettant la photocatalyse amelioree de composes organiques
Devipriya et al. Solar Photocatalytic Removal of Chemical and Bacterial Pollutants from Water Using Pt/TiO2‐Coated Ceramic Tiles
Abualnaja et al. Development of photo-induced Ag0/TiO2 nanocomposite coating for photocatalysis, self-cleaning and antimicrobial polyester fabric
Pillai et al. Photocatalysis as an effective advanced oxidation process
Tiwari et al. Facile synthesis and characterization of nanocomposite Au0 (NPs)/titanium dioxide: Photocatalytic degradation of Alizarin Yellow
Sutanto et al. Synthesis and characterization of ZnO: TiO2 nano composites thin films deposited on glass substrate by sol-gel spray coating technique
Chen et al. A study on photodegradation of trichloroethylene using an optical fiber coated with different photocatalysts
Yepseu et al. Optical and photocatalytic properties of CuxS/ZnO composite thin films deposited by robotic spray pyrolysis deposition
LADUM MATERIALS AND METHODS FOR ENHANCED PHOTOCATALYZATION OF ORGANIC COMPOUNDS WITH
Divya et al. Nano-photocatalysts in the treatment of colored wastewater-a review
Jianqiao et al. Semiconductor photocatalyst of tin oxide quantum dots prepared in aqueous solution for degradation of organic pollutants in contaminated water
Nyangiwe et al. The decolourisation of Methyl Orange and textile effluent under UV using commercial and synthesized nano-TiO2
Shinde et al. Solar light assisted photocatalysis of water using a zinc oxide semiconductor
Kato et al. Photocatalytic Degradation of Phenol with Ultrasonic Mist and Sunlight
Aziz et al. Recent progress on development of TiO2 thin film photocatalysts for pollutant removal

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AT AU BB BG BR CA CH CS DE DK ES FI GB HU JP KP KR LK LU MG MN MW NL NO PL RO RU SD SE US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU MC NL SE BF BJ CF CG CI CM GA GN ML MR SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref country code: US

Ref document number: 1994 244149

Date of ref document: 19940725

Kind code of ref document: A

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA