Abstract: A device comprising a measuring device for determining the flow rate of a water stream, a measuring device for determining the concentration of hydrogen peroxide in the water stream, a measuring device for determining the concentration of peracetic acid in the water stream, a metering device for metering a reducing agent into the water stream downstream of the measuring devices for the concentrations, and a control device which, from the flow rate of the water stream, the concentration of hydrogen peroxide in the water stream and the concentration of peracetic acid in the water stream, calculates an amount of reducing agent for reducing the content of hydrogen peroxide and peracetic acid to a desired value and actuates the metering device for metering the reducing agent, makes possible reliable reduction of the content of hydrogen peroxide and peracetic acid in a water stream.

Abstract: The present invention is directed to pulverulent mixtures comprising hydrogen peroxide and hydrophobized, pyrogenically prepared silicon dioxide powder, preferably with a methanol wettability of at least 40. The pulverulent mixtures exhibit good storage stability and can be used for the controlled release of hydrogen peroxide and/or oxygen. The invention also includes methods of making these pulverulent mixtures and methods of using the mixtures in detergents, cleaning compositions, topical medications, antimicrobials and other products.

Abstract: Pulverulent mixture comprising hydrogen peroxide and hydrophobized, pyrogenically prepared silicon dioxide powder, wherein the hydrophobized silicon dioxide powder has a methanol wettability of at least 40 and is present to the extent of less than 9 wt. %, based on the total weight, and the content of hydrogen peroxide, based on the total weight, is between 10 and 50 wt. % It is prepared by a process in which hydrophobized silicon dioxide powder with a methanol wettability of more than 40 is treated with an aqueous hydrogen peroxide solution at temperatures of not more than 70° C. It can be used in detergents, in cleaning compositions and in skin and hair treatment compositions.

Abstract: Pulverulent mixtures containing hydrogen peroxide and hydrophobised silicon dioxide are used for the controlled release of hydrogen peroxide and/or oxygen. The controlled release can take place in a time-delayed manner or by the application of pressure. Hydrogen peroxide can be released into aqueous or pulverulent media and in emulsions, gels, creams or pastes.

Abstract: Method for reducing harmful organisms on surfaces in contact with continuously or periodically flowing currents of cooling water used for throughflow cooling without recirculation, wherein the harmful organisms are algae, mussels and slime forming organisms, by periodically adding an aqueous treatment agent containing at least one peroxycarboxylic acid with 1 to 6 C atoms to the flowing water once every 5 to 100 hours over a period of 3 to 60 minutes in an amount corresponding to at least 1 ppm of peroxycarboxylic acid to reduce growth of the organisms on the surfaces.

Abstract: Method for reducing harmful organisms on surfaces in contact with continuously or periodically flowing currents of cooling water used for throughflow cooling without recirculation, wherein the harmful organisms are algae, mussels and slime forming organisms, by periodically adding an aqueous treatment agent containing at least one peroxycarboxylic acid with 1 to 6 C atoms to the flowing water once every 5 to 100 hours over a period of 3 to 60 minutes in an amount corresponding to at least 1 ppm of peroxycarboxylic acid to reduce growth of the organisms on the surfaces.

Abstract: A method for preserving wood that includes impregnating the wood with a wood preservative agent based on one or more compounds of at least one metal of the 1st and/or 2nd subgroups of the periodic system and fixing the metal(s) for purposes of reducing the danger of leaching. The wood is (i) impregnated with a preservative containing a water-soluble zinc compound or (ii) wood that has already been impregnated with a zinc-free preservative or one that contains at least one metal compound of the 1st and/or 2nd subgroups is impregnated with a second preservative that contains at least one water-soluble zinc compound, and wood impregnated in accordance with (i) or (ii) is impregnated with an aqueous solution of a salt of trimercapto-s-triazine (TMT), dithiocarbamate or trithiocarbonate.

Abstract: A method for preserving wood that includes impregnating the wood with a wood preservative agent based on one or more compounds of at least one metal of the 1st and/or 2nd subgroups of the periodic system and fixing the metal(s) for purposes of reducing the danger of leaching. The wood is (i) impregnated with a preservative containing a water-soluble zinc compound or (ii) wood that has already been impregnated with a zinc-free preservative or one that contains at least one metal compound of the 1st and/or 2nd subgroups is impregnated with a second preservative that contains at least one water-soluble zinc compound, and wood impregnated in accordance with (i) or (ii) is impregnated with an aqueous solution of a salt of trimercapto-s-triazine (TMT), dithiocarbamate or trithiocarbonate.

Abstract: Hardness-stabilizing and scale-preventing aqueous percarboxylic acid solutions contain a hardness stabilizer selected from the group (i) polymers prepared by oxidative polymerization of acrolein or of acrolein and acrylic acid, (ii) polyacrylic acid, (iii) copolymers of acrylic acid and another unsaturated carboxylic acid and (iv) polymaleic acid, wherein the average molecular weight Mw of the hardness stabilizer is in the range 500 to 25000, and the solutions are obtained by adding the hardness stabilizer to a percarboxylic acid solution. Preferred solutions contain a hardness stabilizer (i) with a Mw of 1000 to 15000. The solutions may also contain a surfactant. The solution can be used for controlling microorganisms in aqueous systems, in particular water-circulating systems.