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Nederlandse Centrale Organisatie Voor Toegepast-natuurwetenschappellijk

Aris Van Elven

Henricus C Buys

Aart J Naaktgeboren

Henricus G Overmars

Dirk A Noordegraaf

A semipermeable composite membrane on a microporous substrate, such as a polysulphone membrane having on its surface a semipermeable membrane being the reaction product of a polyamine, a water soluble polymer of formula 1 ##STR1## wherein R is hydrogen or an hydrocarbongroup, x is 0-99.9%, and y is 100-x mol. % and n indicates the molecular weight and of a crosslinking agent containing a polyfunctional group having reacted with the amino groups of the polyamine and of the polymer. In the formula 1 preferably R is an alkylgroup of 1-5 carbon atoms, particularly methyl, and n is equivalent to a mol. weight of more than 10.000. The water soluble polymer is advantageously a mixture of a polymer of formula 1 wherein x and y are both 50 mol. % and a polymer of formula 2, ##STR2## this last mentioned polymer being preferably obtained by hydrolysis of a compound of formula 1. The degree of hydrolysis is preferably 70 to 99.9%. The crosslinking agent is preferably a mixture of iso phtaloylchloride and trimesoylchloride; the polyamine is preferably an azolalkane compound having terminal amino groups with a straight chain comprising 8 to 24 carbon atoms, particularly 1.10-diamino-4.7-diazadecane; 1.14-diamino-4.8.11-triazatetradecane and 1.18-diamino-4.8.11.15-tetraazooctadecane. The flux of the membrane is at least 40 l/m.sup.2.h and the salt retention at least 90%.

Semipermeable composite membrane

The invention relates to polyetherurethane particles having absorptive activity whereby these particles may be applied for the extractions or the separations of metal ions from liquids, e.g. from waste liquors leaving galvanizing, printing and metal working industries. The particles are of a spherical shape, have a bulk density of at least 0.5 g/cm.sup.3 and are resistant against acidic liquids. The invention provides a method for such extractions and separation. The invention provides also a method for production of the polyetherurethane particles by forming a prepolymer and subjecting the dissolved prepolymer in the presence of 2-methylpiperazine suspension to polycondensation.

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Leersum, Netherlands

Aris Van Elven