Redox-driven stable isotope fractionation in transition metals: Application to Zn electroplating

Stable Isotopes of Transition and Post-Transition Metals as Tracers in Environmental Studies

“…Cadmium has an even lower boiling point (~760 C) than Zn, and like Zn, Cd in ores likely evaporates during smelting favoring escape of light Cd isotopes in the exhaust, as recently demonstrated by Cloquet et al (2006a). Cadmium behaves like Zn during electroplating (Kavner et al 2008), potentially resulting in a large pool of isotopically light Cd in the environment. Although Cd is discussed in this chapter mainly in a multi-tracer context, Rehk€ amper et al (2011) provide a thorough discussion of the application of Cd isotopes in environmental studies.…”

“…Thus Zn can evaporate from ore during smelting, which would favor escape of light Zn isotopes in the exhaust as demonstrated by Mattielli et al (2009), and retention of heavy Zn isotopes in the slag residue as shown by Sivry et al (2009). Kavner et al (2008) demonstrated that electroplated Zn, reduced to metallic state from a large pool of aqueous Zn(II), is isotopically light compared to the parent solution, potentially resulting in a large pool of isotopically light electroplated Zn in the environment. In addition, Weiss et al (2007) demonstrated that Zn adsorption due to complexation by organic compounds is selective for the heavy Zn isotopes, resulting for example in peat samples that have heavier Zn isotope compositions than any potential natural source.…”

“…Examples of processes resulting in kinetic isotope effects are evaporation, where light isotopes of metals such as Zn and Cd escape more efficiently at the liquid-air interface than heavy isotopes (e.g. Cloquet et al 2006a, b), electroplating, where light isotopes of metals from the plating bath are preferentially deposited onto a metal substrate (Kavner et al 2008), and diffusion (Richter et al 2009). A special class of kinetic isotope effects arises for elements having differences in specific isotope reaction rates, for example where the odd-numbered isotopes of Hg behave non-systematically with respect to the even-numbered isotopes (Bergquist and Blum 2009;Blum 2011 .…”

Tracing of anthropogenic zinc sources in coastal environments using stable isotope composition

“…13 experiments (Kavner et al,2008, Black et al, 2011Black et al, 2014). The exact contribution of roasting and electroplating steps on the overall zinc isotope fractionation of ores and wastes is difficult to determine.…”

“…Previous work suggested that zinc isotopes fractionate during major anthropogenic process such as smelting (Shiel et al, 2010, Weiss et al, 2007, combustion (Matielli et al, 2007, Ochoa andWeiss, 2015) and electroplating (Kavner et al, 2008), generating anthropogenic fingerprints isotopically distinct from natural isotopic compositions (Guegien, 2008;Yin et al, 2016,). High-temperature processes involved during roasting and smelting of ores tend to fractionate zinc isotopes in the gas phase, with an enrichment of the lightest isotopes in air emissions and heavier isotopes in slags and effluents Borok et al, 2010;Ochoa Gonzalez and Weiss, 2015;Ocho Gonzalez et al, 2016;Yin et al, 2016).…”