Patent ID: 6863812

Claim:
A collector cassette used to trap dissolved metals in seawater in which a plurality of collectors are superposed and sandwiched between two nets to make a collector unit and a plurality of such collector units are stacked at suitable spacing and fixed by bolts to make a collector cassette, the collector having an amidoxime group and a hydrophilic group for removing dissolved metals from seawater which is produced by the steps of, exposing a substrate fiber in the form of either a nonwoven or woven cloth to a radiation to generate a reaction initiating radical on the fiber, wherein the nonwoven or woven cloth is made of a fiber of a core/sheath structure that has a polyolefinic fiber coated with a different polyolefin, co-grafting a polymerizable monomer having a cyano group onto the radiated polyolefin fiber in the presence of a polymerizable monomer having a hydrophilic group, and reacting the cyano groups in the graft side chains with hydroxylamine to convert them to amidoxime groups, whereby both amidoxime and hydrophilic groups are introduced into the same graft side chains and wherein the amidoxime group and hydrophilic groups are introduced at a molar ratio of 70:30-30:70.