Method of treating aqueous liquids using light energy, ultrasonic energy, and a photocatalyst
AssigneeSRI International
InventorAllan J. Johnston
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Abstract
A process for efficiently removing halogenated organic compounds from contaminated aqueous liquids is described which comprises contacting the contaminated liquid with a photocatalyst while simultaneously exposing the contaminated liquid to both acoustic energy and light energy to efficiently decompose the halogenated organic compounds.
Claims26
A process for the treatment of an aqueous liquid containing a halogenated organic compound which consists of:
- a) contacting the aqueous liquid with a semiconductor photocatalyst while;
- b) irradiating the aqueous liquid with light of a wavelength higher than the band gap of the semiconductor photocatalyst;
- and
- c) simultaneously exposing the aqueous liquid to acoustical energy.
The process for the treatment of an aqueous liquid containing a halogenated organic compound to decompose said halogenated organic compound which consists of:
- a) contacting said aqueous liquid with a photocatalyst while;
- b) irradiating the aqueous liquid with light of a wavelength ranging from about 250 to about 450 nm;
- and
- c) simultaneously exposing said aqueous liquid to acoustical energy.
A process for the treatment of an aqueous liquid containing a halogenated organic compound to decompose said halogenated organic compound which consists of:
- a) contacting said aqueous liquid with a particulated photocatalyst while;
- b) irradiating the aqueous liquid with light of a wavelength ranging from about 250 to about 450 nm while;
- c) simultaneously exposing said aqueous liquid to acoustical energy;
- and
- d) separating said liquid from said particulated photocatalyst and from residues remaining after decomposure of said halogenated organic contaminants.
A process for purifying an aqueous liquid containing halogenated organic contaminants by decomposing said contaminants which consists of:
- a) mixing said liquid with a particulate photocatalyst to form a suspension of said particulate photocatalyst and said liquid having a concentration of from about 100 milligrams to about 2 grams of said photocatalyst per liter of liquid;
- b) exposing said suspension to light radiation of energy higher than the band gap of said photocatalyst;
- c) simultaneously exposing said suspension to ultrasonic energy within a range of from about 1 KHz to about 1 MHz at a power level equivalent to a range of from about 10 to about 2,500 watts for a 2 liter vessel;
- and
- d) separating said liquid from said particulated photocatalyst after decomposure of said halogenated organic contaminants.
A process for purifying water containing halogenated organic contaminants by decomposing said contaminants which consists of:
- a) mixing said liquid with a particulate photocatalyst having a particle size range of from about 0.05 to about 4,000 microns to form a suspension of said particulate photocatalyst and said liquid having a concentration of from about 100 milligrams to about 2 grams of said photocatalyst per liter of liquid;
- b) passing said suspension through an optical cell to expose said suspension to light radiation having a wavelength range of from about 250 to about 450 nm at an energy density level of at least about 1,000 microwatts/in.sup.2 of exposure area per liter of liquid;
- c) simultaneously exposing said suspension flowing through said optical cell to ultrasonic energy within a range of from about 1 KHz to about 1 MHz at a power level equivalent to a range of from about 10 to about 2,500 watts for a 2 liter vessel;
- and
- d) separating said particulated photocatalyst and decomposition products of said halogenated organic contaminants from said liquid.
A process for purifying contaminated water containing halogenated organic contaminants by decomposing said contaminants which consists of:
- a) mixing said contaminated water with particulate TiO.sub.2 having a particle size range of from about 0.05 to about 4,000 microns to form a suspension of said particulate TiO.sub.2 and said water having a concentration of from about 100 milligrams to about 2 grams of said TiO.sub.2 per liter of contaminated water;
- b) passing said suspension through an optical cell to expose said suspension to ultraviolet light radiation of from about 300 to about 360 nm at an energy density level of at least about 1,000 microwatts/in.sup.2 of exposure area per liter of liquid;
- c) simultaneously exposing said suspension flowing through said optical cell to ultrasonic energy within a range of from about 1 KHz to about 1 MHz at a power level equivalent to a range of from about 10 to about 2,500 watts for a 2 liter vessel;
- and
- d) separating said particulated TiO.sub.2 photocatalyst and decomposition products of said halogenated organic contaminants from said liquid.
Dependencies are inferred from the claim text.