| 摘要 |
PURPOSE:To remove harmful heavy metal ions dissolved in water effectively by adsorption with an adsorbent consisting of a condensation product of methylolated thiourea with polyethyleneimine. CONSTITUTION:Thiourea or N-substituted compound such as diethylthiourea, ethylenethiourea, etc. is reacted with formaldehyde to produce methylolated compound. The resulting methylolated thiourea or N-substituted methyloltiourea is condensed with polyethyleneimine in an aqueous medium while adjusting the pH with an addition of sulfuric acid. When the condensation reaction is conducted in a ratio of 0.25 to 5 moles of methylolthiourea per monomer unit of polyethyleneimine, the reaction of methylol group(s) with primary and secondary amino groups of polyethyleneimine affords the desired adsorbent. Harmful heavy metals such as mercury, lead, cadminum, etc. can be removed effectively by this adsorbent. |
