A green method based on living macroalgae for the removal of rare-earth elements from contaminated waters

João Pinto; Bruno Henriques; José Soares; Marcelo Costa; Mariana Dias; Elaine Fabre; Cláudia B Lopes; Carlos Vale; José Pinheiro-Torres; Eduarda Pereira

doi:10.1016/j.jenvman.2020.110376

A green method based on living macroalgae for the removal of rare-earth elements from contaminated waters

J Environ Manage. 2020 Jun 1:263:110376. doi: 10.1016/j.jenvman.2020.110376. Epub 2020 Apr 24.

Authors

Affiliations

¹ Department of Chemistry, University of Aveiro, Aveiro, Portugal; CICECO - Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal.
² Department of Chemistry, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal; LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal. Electronic address: brunogalinho@ua.pt.
³ Department of Chemistry, University of Aveiro, Aveiro, Portugal.
⁴ Department of Chemistry, University of Aveiro, Aveiro, Portugal; CICECO - Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal.
⁵ CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, Matosinhos, Portugal.
⁶ N9VE - Nature, Ocean and Value, Lda, Porto, Portugal.
⁷ Department of Chemistry, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal; LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal.

PMID: 32174523
DOI: 10.1016/j.jenvman.2020.110376

Abstract

Low recycling rates of rare earth elements (REEs) are a consequence of inefficient, expensive and/or contaminating methods currently available for their extraction from solid wastes or from liquid wastes such as acid mine drainage or industrial wastewaters. The search for sustainable recovery alternatives was the motivation for this study. For the first time, the capabilities of 6 living macroalgae (Ulva lactuca, Ulva intestinalis, Fucus spiralis, Fucus vesiculosus, Osmundea pinnatifida and Gracilaria sp.) to remove REEs (Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy) from laboratory-prepared seawater spiked with REE solutions were evaluated. The assays lasted 72 h with REEs concentrations ranging from 10 to 500 μg L^-1. The link between REEs uptake and algal metabolism, surface morphology and chemistry were addressed. Kinetics varied among the species, although most of the removal occurred in the first 24 h, with no equilibrium being reached. Lack of mortality reveal that the algae maintained their metabolism in the presence of the REEs. Green alga U. lactuca stood out as the only capable of efficiently removing at least 60% of all elements, reaching removals up to 90% in some cases. The high bioconcentration factors, derived from mass balance analysis (c.a. 2500) support that the REEs enriched algal biomass (up to 1295 μg g^-1) may constitute an effective and environmentally friendly alternative source of REEs to conventional extraction from ores.

Keywords: Bioaccumulation; Gracilaria sp.; Rare earth elements; Recycling; Ulva lactuca; Water treatment.

MeSH terms

Gracilaria*
Metals, Rare Earth*
Seaweed*
Ulva*
Water Pollution

Substances

Metals, Rare Earth