The role of organic colloids in the sequestration and mobilization of copper in smelter-impacted soils

Abstract

This study shows that Cu occurs predominantly as Cu-sulfides and Cu-bearing phosphates and -carbonates in organic matter (OM) colloids within smelter-impacted soils in which they are often associated with other...

Atom probe tomography and transmission electron microscopy: a powerful combination to characterize the speciation and distribution of Cu in organic matter

“…3-7). These conclusions are in accord with the observations by Mantha et al 28 and Jadoon and Schindler 29 who showed that higher concentrations of Cu occurred in altered OM and on surfaces of silica inclusions within mineralized OM. The latter authors argued that the adsorption of Cu 2+ on silanol groups resulted subsequently in the heterogeneous nucleation of covellite nanoparticles on the surface of the silica inclusions.…”

“…S1 †). The sample contains Cu, Zn and Pb concentrations above the average of all collected samples (Tables S1 and S2 29 Size and chemical composition of organic particles OM particles are mainly in the ne to coarse sand size fraction (>180 mm) and contain Fe-, Cu-, Zn-and S-bearing phases within their porous matrix and on their surfaces. Some of these phases occur as euhedral to anhedral particles.…”

“…2). 29,52,53 Diffusion. Hydrous amorphous silica is colloidal in nature, has a high surface area (>400 m 2 g À1 (ref.…”

“…The authors proposed that the Cu-NP formed through the diffusion of Cu- and S-bearing species into the interior of the OM and the reduction of these species resulted in the formation of metallic Cu and CuS x phases within OM. Jadoon and Schindler 29 characterized the sequestration of Cu-bearing nanoparticles within organic colloids in surficial soils at two distinct sites around the smelter in Rouyn-Noranda, Quebec, Canada. The authors showed that in thin soils overlying bedrock secondary Cu-sulfide (CuS x ) nanoparticles were often associated with other inorganic phases such as Fe-(hydr)oxide and amorphous silica.…”

“…In this study, we will use the combination of transmission electron microscopy (TEM) and atom probe tomography (APT) to explore the occurrence and distribution of Cu-bearing nanoparticles and -precursors in OM particles, collected from the surficial forest soil site in Rouyn-Noranda previously described by Jadoon and Schindler. 29 This study will specifically examine the sequestration of Cu by OM in a S-depleted environment ( i.e. with S concentrations below the detection limit of an energy dispersive spectroscopy (EDS) system (<0.1 wt%)).…”