1 Chemical products, biological preparations, bacteriological preparations for use in the treatment of water, water purification and industrial effluent treatment; filtering materials; ceramic materials for filtration; ceramic materials for reverse osmosis; chemical products for the industrial treatment of liquids; ion exchangers; organic and/or mineral chemical products, in particular ceramics used especially in manufacturing filtering parts, filtration or reverse osmosis filters and membranes; chemical products, catalysts, additives, chemical intermediates, active principles, extracts of purified natural essences, for use in the following industries, namely pharmaceutics, cosmetics, electronics, foodstuffs, colorants, textiles, painting, glassware, nuclear engineering, metallurgy, plastics; cleaning and sterilising products for resins in particular ion exchangers; chemical products, fluids, especially eluents for use in chromatography and crystallography, in particular for use in preparative chromatography; chemical products for separation or fractionation processes using chromatography; intermediary products for the synthesis of pharmaceutical, veterinary, sanitary and cosmetic active principles