Use of some hydrazine derivatives for the separation of mercury(II) from aqueous solutions by flotation technique

Some hydrazine derivatives viz; pyridinium chloride acetylhydrazine (PAH), 1-acetylpyridinium chloride-4-phenylthiosemicarbazide (APPT), 1-acetylpyrid inium chloride-o-hydroxyacetophenone hydrazone (APHH), trimethylammonium ch loride acetylhydrazine (TAH), 1-acetyltrimethylammonium chloride-o-hydroxya cetophenone hydrazone (ATHH) and 1-acetyltrimethylammonium chloride diacety lmonoxime hydrazone (ATDH) are investigated as floating agents for the sepa ration of mercury (If) using oleic acid surfactant. Of these, APPT is the m ost suitable for giving maximum flotation efficiency(similar to 100 %). Sur factant, metal ion and ligand concentrations, ionic strength, foreign ions, pH and temperature are examined as important parameters affecting the floa tability of Hg(II). The procedure is successfully applied to recover Hg(II) from some natural water samples with a relative standard deviation of 1.6 %. Moreover, the mechanism of flotation is suggested based on some physical and chemical studies on the solid complexes isolated from aqueous and scum layers.