A series of hydrophilic cationic polyurethane foams (defined as modified PUFs) were prepared by using N-methyl diethanolamine (defined as N-MDA) as the reactant and treating the foams by hydrochloric acid.The catalytic activity of N-MDA was effectively inhibited by using the mixture of phosphoric acid and acetic acid as the acidic inhibitor and the PUFs were successfully prepared at high amount of N-MDA.The structures and properties of the resulting samples were analyzed by IR spectrometer

contact angle measuring instrument

electronic stripping tester

conductivity meter and zeta potential meter.With increasing the amount of N-MDA

the cation content and hydrophilicity of the samples increased gradually

but the elastic resilience

tensile strength and elongation at break increased first and then decreased.Furthermore

The modified sample was used as a novel microorganism immobilized carrier for adsorbing activated sludge.The results indicated that the modified PUF displayed a higher adsorption rate for activated sludge than the unmodified one (defined as contrast PUF).And its highest adsorption capacity for activated sludge could reach 180 g/L

more than two times of the capacity (80 g/L) of the contrast PUF.The adsorbing processes of these two carriers were explained based on the hydrophilicity of their backbone surfaces and the electrostatic attraction between the carrier and activated sludge.The improved adsorption property should make the modified PUF suitable for application in microbial immobilization.