Abstract: A method of removing surface-deposited contaminants, comprising bringing an ozone-containing treating solution into contact with the surface of a treating target on which contaminants have deposited. The ozone-containing treating solution comprises an organic solvent having a partition coefficient to ozone in a gas, of 0.6 or more, and ozone having been dissolved in the solvent. Contaminants having deposited on the surfaces of various articles including substrates for electronic devices, such as semiconductor substrates and substrates for liquid crystal display devices can be removed by room-temperature and short-time treatment in a high safety and a good efficiency.

Abstract: A method and an apparatus for removing an organic film such as a resist film from a substrate surface are provided. These are very safe even at high temperatures, and use a treatment liquid which can be recycled and reused. A treatment liquid typically formed from liquid ethylene carbonate, propylene carbonate, or a liquid mixture of these two compounds, and in particular such a treatment liquid containing dissolved ozone, is contacted with a substrate with an organic film, and the organic film is removed.

Abstract: A system for producing ultra-pure water having an electrodialysis unit 1, which has a membrane selectively permeable to monovalent cations and a membrane selectively permeable to monovalent anions, and a reverse osmosis unit 5 which is connected after the electrodialysis unit 1 in series.

Abstract: A filter unit comprises a metallic supporting plate possessed of stepped through holes opening with a larger diameter in one main surface and with a smaller diameter in the other main surface (wherein the diameter ratio of larger-diameter openings to smaller-diameter openings is desired to be in the range of 1:0.01 to 1:0.5) or a pressureproof supporting plate having in one surface thereof inclined liquid flow grooves arranged in a radial pattern and concentric circular liquid flow grooves adapted to intersect the radially arranged liquid flow grooves and a membrane filter disposed on the surface of the supporting plate containing larger-diameter openings or liquid flow grooves. This filter unit is ideally used for finely dividing and uniformly sizing suspended lipid particles assuming a definite average particle size and a specific particle size distribution.

Abstract: An apparatus for the treatment of a low-concentration organic waste water for relaim a low-concentration organic waste water having a TOC concentration of from 0.5 to 3 ppm and obtaining an ultra pure water having a TOC concentration of not more than 1 ppb is characterized by the fact that a first treating system comprising a reverse osmosis unit for transforming a low-concentration organic waste water having a TOC concentration of from 0.5 to 3 ppm into a low-concentration organic waste water having a TOC concentration of from 60 to 200 ppb and a vacuum degasifier adapted to admit an inert gas at a volumetric feed flow rate in the range of from 0.001 to 1.0 based on the volume of the waste water under treatment at a vacuum rate of not more than 35 Torrs and a second treating system comprising a low-pressure ultraviolet decomposition unit for emitting an ultraviolet light of a wavelength of 184.

Abstract: A method for vacuum deaeration of a dissolved gas in a pure water, the pure water having a specific resistivity of not less than 0.1 M.OMEGA..multidot.cm, in a vacuum degasifier column maintained at a presssure slightly higher than a saturated steam pressure at a temperature of the pure water, the column having a region filled with packings, spraying the pure water downwardly from above the region and meantime evacuating inside the column to maintain the pressure, the method comprising the steps of: carrying out the evacuation from above the region to maintain a pressure made by adding 1 mmHg to 10 mmHg to the saturated steam pressure at the temperature of the pure water inside the vacuum degasifier column; and introducing an inert gas upwardly from below the region at a volumetric flow rate in the range of from 0.001 to 1.0, based on the volumetric feed flow rate of the pure water taken as 1, simultaneously with the evacuation, to lower a dissolved oxygen concentration in the pure water below 10 ppb.

Abstract: A new process step for purifying water from a small amount, particularly a last trace amount, of organic impurities included in total organic carbon (TOC) content is incorporated into known processes for the preparation of ultra pure water comprising one or more previous filtration steps and a series of purification steps known per se. The new step comprises irradiating the water to be treated with a light in the presence of a photocatalyst comprising an inorganic semiconductor selected from TiO.sub.2, SrTiO.sub.3 and CdS in fine particulate form and a noble metal and/or an oxide thereof selected from Pt, Pd, Ru, RuO.sub.2 and Rh deposited on said semiconductor particles for a period of time sufficient to oxidatively decompose the organic impurities, resulting in a decrease in TOC content of the water to a level lower than the minimum detection level of TOC detectors, typically <0.05 mg C/l or <0.01 mg C/l depending upon the sensitivity of particular detectors available up to date.

Abstract: A method and an apparatus for measuring an impurity concentration of a liquid comprises atomizing step for atomizing the objective liquid, e.g. pure water, having a predetermined droplet size distribution, and an evaporating step for evaporating to dryness the droplets so as to generate fine particles. Those particles are fed to a condensation nuclei counter, hereinafter referred to as CNC, which counts the number of fine particles and has a specified sensitivity characteristic curve. Then impurity concentration of the objective liquid can be measured, since the concentration is related to the counted number of the CNC, the distribution of droplet size of the atomizer, and the sensitivity characteristic of the CNC including the particle deposition loss.