Abstract
Water-soluble poly (methacrylohydrazide) (PMH) was prepared by the hydrazinolysis of poly (methyl methacrylate) (PMMA) with hydrazine hydrate (HH), and the removal of heavy metals from an aqueous solution by the PMH was investigated. Removal was carried out by precipitation or flotation method. As PMH was found to form water-insoluble polymer complexes with heavy metals, especially with mercury, at various pH value, the removal of mercury from an aqueous solution could easily be carried out by the filtration of the precipitates. The highest removability was observed when PMH, prepared from PMMA (M. W.225 x 1O2-) and HH, was added to Hg2+ solution in a molar ratio of 3-4 hydrazide groups to one Hg2+, and more than 98.5% of Hg2+ was removed from the aqueous solution containing Hg2+ (10 me). When excess PMH was added to the Hg2solution, it was found that the polymer complexes tended to redisperse into water. Introducing styrene, a hydrophobic group, into PMH prevented the redispersion of the precipitate. It was found that the selective removal of Hg"could be carried out by changing the pH of the aqueous solutions containing mercury and other metals.
