abstract
The present study tested whether the presence of potentially toxic elements (PTEs) (Cd, Cr, Cu, Pb, Hg and Ni), commonly found in wastewaters, interferes with the ability of macroalgae (Ulva intestinalis, Ulva lactuca, Fucus spiralis, Fucus vesiculosus, Gracilaria sp. and Osmundea pinnatifida) to remove rare earth elements (REEs) (La, Ce, Pr, Nd, Eu, Gd, Tb, Dy and Y), which are key elements for most high technologies (e.g. electronics, aerospace, renewable energy). Results proved the high capacity of living macroalgae to remove REEs from multielement solutions, with the following sequence of bioconcentration factors being observed: U. intestinalis (2790) > Gracilaria sp. (2119) > O. pinnatifida (1742) > U. lactuca (1548) > F. vesiculosus (944) > F. spiralis (841). Competition among REEs to sorption sites on the six macroalgae was minor due to the chemical similarities between the elements. However, Ce and Y were the less removed while Gd, La and Eu the most removed among REEs. Ionic strength was an important factor in the sorption process, with salinity affecting differently the six macroalgae. Surprisingly, the presence of potential toxic elements in solution enhanced the removal of REEs. The most plausible explanation is the preferentially complexation of those elements by carbonates over REEs, which facilitates the binding of REEs cations onto the surface of macroalgae. (C) 2020 Elsevier Ltd. All rights reserved.
keywords
HEAVY-METALS; SIMULTANEOUS REMOVAL; ULVA-LACTUCA; BIOSORPTION; BIOACCUMULATION; BIOTECHNOLOGY; ADSORPTION; CHEMISTRY; RECOVERY; SINGLE
subject category
Environmental Sciences & Ecology
authors
Costa, M; Henriques, B; Pinto, J; Fabre, E; Dias, M; Soares, J; Carvalho, L; Vale, C; Pinheiro-Torres, J; Pereira, E
our authors
Elaine Fabre
PhD Studentacknowledgements
Bruno Henriques benefited from a Research position funded by national funds (OE), through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Thanks are also due to the financial support to REQUIMTE, CESAM and CIIMAR (UIDB/50006/2020, UIDB/50017/2020thornUIDP/50017/2020 and UID/Multi/04423/2019, respectively), to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020, and to N9VE - Nature, Ocean and Value, Lda, for their cooperation in this work.