Abstract: The invention relates to a method for photocatalytic separation of a dispersed substance from a surfactant-containing dispersion. The surfactant-containing dispersion contains at least one dispersant, one dispersed substance, one surfactant and one photocatalyst. Irradiation of the photocalyst causes the decomposition or modification of the surfactant allowing for the separation of the dispersed substance from the dispersant.

Abstract: A powdery photocatalyst based on titanium dioxide displays a bimodal particle size distribution of primary particles, with one particle component under about 30 nm and a second particle component over about 100 nm. The photocatalyst is manufactured by mixing at least two TiO2 components. One component is a TiO2 photocatalyst which is active in UV light and/or in visible light and which displays a specific surface according to BET of at least about 120 m2/g. The second component is anatase and/or rutile displaying a specific surface according to BET of less than about 50 m2/g. The two components are contained in the photocatalyst at a weight ratio of 1:1000 to 1000:1.

Abstract: A method and material for improved TiO2 pigment for paper and laminates is described. Phosphorous, titanium, and aluminum compounds are successively added to a TiO2 pigment suspension. Resulting pigments show improved greying resistance and hiding power over prior art pigments, and show improved results as pigments in tests of paper and laminates.

Abstract: A method and material for improved TiO2 pigment for paper and laminates is described. Phosphorous, titanium, and aluminum compounds are successively added to a TiO2 pigment suspension. Resulting pigments show improved greying resistance and hiding power over prior art pigments, and show improved results as pigments in tests of paper and laminates.

Abstract: A method for preparing high quality pigments having improved wettability, dispersibility and gloss characteristics, which method comprises grinding a pigment base material in a jet mill in the presence of an organic grinding aid, recovering ground pigment particles having a first organic layer, comprising the organic grinding aid, and treating the recovered pigment particles with an organic material, forming a second organic layer on the pigment particles, for improving the wettability, dispersibility and gloss characteristics of the treated pigment particles. Titanium dioxide, both untreated and pretreated with an inorganic coating, may be processed according to the method herein to yield high quality titanium dioxide pigment having improved wettability, dispersibility and gloss characteristics. The titanium dioxide pigment is particularly suitable for use in water-thinnable paint systems.

Abstract: A mixture of oligomers of alkylalkoxysilanes condensed in the chain and/or cyclic form, said mixture of oligomers containing less than 2% by weight of free alcohols and the condensed alkoxysilanes satisfying formula I: ##STR1## wherein R is an alkyl group having 3 to 18 carbon atoms, and each R' is a member (i) selected from the group consisting of methyl, ethyl or hydrogen, or is (ii) methyl or hydrogen, or is (iii) ethyl or hydrogen, the degree of oligomerization being in the range 2.ltoreq.x.ltoreq.20 and the quotient of the molar ratio ?Si/alkoxy group!.gtoreq.1; and/orsatisfying formula II: ##STR2## in which R is an alkyl group having 3 to 18 carbon atoms, and each R' is a member (i) selected from the group consisting of methyl, ethyl or hydrogen, or is (ii) methyl or hydrogen or is (iii) ethyl or hydrogen, the degree of oligomerization being x.gtoreq.3 and the quotient of the molar ratio ?Si/alkoxy group!.gtoreq.1.

Abstract: Subpigmentary titanium dioxide with decreased photoactivity is produced if known ions for increasing photostability in titanium dioxide pigments are not deposited on the surface of the subpigmentary particles, but instead are included intracrystallinely in the pigment particle (i.e., doped). In a preferred process for preparation of doped subpigmentary titanium dioxide particles, an acid solution containing the dopant is added in two stages to a suspension of subpigmentary titanium dioxide.

Abstract: A process produces fine particle titanium dioxide essentially transparent to visible light and essentially UV radiation absorbing. During preparation of the titanium dioxide product, tin dioxide with a particle size of 1 to 10 nm, and preferably 1 to 4 nm, is added, in an amount of 0.5 to 10 weight percent with respect to TiO.sub.2. The particle size of the titanium dioxide is specifically adjusted by the tin dioxide addition. Acicular particles are rounded by heat-treatment between 300.degree. and 800.degree. C., and preferably between 400.degree. and 600.degree. C. The particles can be post-treated to produce a coating of inorganic and/or organic substances. The fine particle titanium dioxide can be prepared by the decomposition of sodium titanate with hydrochloric acid or by suitable hydrolysis of a tetravalent titanium compound which leads to rutile formation.