Phase Fractionation of Chemical Elements in the Mixing Zones of Acidic Volcanic and Sea Waters: Experimental Modeling Data

— Experiments on modeling the phase fractionation of trace elements (Mn, Co, Ni, Cu, Zn, Cd, Pb, Tl, Ga, Y, REE, V, As, Sb, and U) at interaction between acidic volcanic waters with seawater, accompanied by the sequential precipitation of Fe and Al hydroxides, show that the coprecipitation efficiency of various trace elements with Fe and Al hydroxides differs. The most dramatic differences were found for Ga and REE: Ga is predominantly accommodated by Fe hydroxide, whereas REE are bound mostly to Al hydroxide. It was established that, in addition to pH value, the degree of coprecipitation of trace elements also depends on the relative volume fraction of seawater, with its increase likely leading a shift in the adsorption equilibrium and, as a consequence, to a change in the coprecipitation efficiency of trace elements.