Interaction between Selenium Derivatives and Heavy Metal Ions: Cu2+and Pb2+

✍ Scribed by Giorgio Feroci; Adamo Fini; Roberto Badiello; Alberto Breccia

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 118 KB
• Volume: 57
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1997.1494

✦ Synopsis

The interaction between selenium derivatives (sodium selenate, sodium selenite, selenourea, and DL-selenomethionine) and heavy metal ions (Cu 2/ and Pb 2/ ) was studied by polarography in aqueous solutions. Selenate does not interact with the selected ions; while selenite form a 1:1 soluble complex with Pb 2/ (Kf Å 4.9 1 10 4 ) and a poorly soluble salt with Cu 2/ (K ps Å 3.8 1 10 09 ). DL-Selenomethionine forms a colloidal complex with Cu 2/ (K f Å 1.4 1 10 4 ), while does not interact with Pb 2/ . Pb 2/ ions also display a poor affinity for selenourea: the system is not stable, because oxidation and hydrolysis of selenourea and precipitation of lead (II) selenide can occur. In the presence of Cu 2/ , selenourea forms a complex. The potential for the oxidation of selenourea and the reduction of Cu 2/ ions originated mixed currents (cathanodic wave). For comparison also systems containing thiourea and methionine were considered.