Process for producing reduced keratinous substances using urea or thiourea

摘要

A process for producing a reduced keratinous substance having a high adsorptive power for cationic substances, which comprises reducing a substance containing keratin as a main ingredient under alkaline conditions to cleave the disulfide linkages of the keratin, dissolving the reduced keratin in an aqueous medium containing urea or thiourea in a concentration of less than 5 moles/liter, and then acidifying the resulting solution to precipitate the dissolved reduced keratin under such conditions that the thiol side-chains present in the reduced keratin do not substantially undergo oxidation. The reduced keratinous substance is especially useful as a heavy metal ion capturing agent.