Influence of surface-active substances on the redox processes of metal ions: a contribution to the speciation analysis of metals in aquatic systems

✍ Scribed by Marta Plavšií; Božena Ćosović

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 676 KB
• Volume: 284
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)85060-7

✦ Synopsis

Ah&net

The cathodic (reduction) and anodic (oxidation) waves of different heavy metal ions (Cu, Cd, In, Pb, 'II) were investigated in the presence of the non-ionic surfactant Triton X-100 and humic acid (HA) by electrochemical methods (differential-pulse voltammetry and a.c. voltammetry). The adsorption and complexation properties of the organic substances were also examined. Conclusions about the possible influences of organic matter on the speciation analysis of heavy metal ions in the bulk solution and on the mercury/water interface are drawn. For Cu the predominant reaction with HA will be complexation even at lower pH (1.6). In neutral and alkaline solutions Cd and Pb ions will be complexed either in the bulk of solution or at the electrode surface. At lower pH inhibition of oxidoreduction processe s occurred owing to surface coverage of the electrode. Indium will be. complexed with HA present at higher pH (3.&I), whereas at lower pH the hydrophobic/hydrophilic effects play an important role in the interfacial region. Owing to the low tendency to form complexes and the small sire of thallium ion, its oxidoreduction processes are not infhrenced by the presence of either Triton X-100 or HA.