Modified polyurethane foamed materials used as adsorbents

A process for producing polyurethane foams by reacting polyisocyanates with compounds having at least two hydrogen atoms which are reactive toward isocyanates, which comprises applying

• (i) ethylenimine, polyethylenimine, polyvinylamine, polyvinylamine copolymers, carboxymethylated polyethylenimines, phosphonomethylated polyethyleneimines, quarternized polyethylenimines and/or dithiocarbamatized polyethylenimines or
• (ii)alkali metal hydroxides and/or alkaline earth metal hydroxides or a mixture of (i) and (ii)
• to the surface of the foam.