COAGULANT AND METHOD OF TREATMENT BY COAGULATION

摘要

A coagulant comprising a soluble amidine polymer which can be produced at low cost is provided without using a conventional process for coagulant production in which an N-vinylcarboxamide is used and this results in a high cost. This coagulant is usable in the treatment of the water obtained by sludge dehydration from municipal sewage or industrial wastewater, treatment of dyeing wastewater, treatment of raw water for tap water, treatment of a waste-paper dispersion containing ink particles to be separated (deinking treatment), and treatment of a papermaking feedstock before papermaking. The coagulant is further usable as an internal additive for papermaking and applicable to a color additive in coating materials for ink-jet printing paper. This coagulant comprises a water-soluble polymer having specific repeating units which has been produced by subjecting a copolymer of (meth)acrylamide and (meth)acrylonitrile to the Hofmann reaction, subsequently neutralizing the resultant polymer with an acid, and heat-treating the polymer. Also provided is a method of coagulation with the coagulant.