title: Cork stoppers as an effective sorbent for water treatment: the removal of mercury at environmentally relevant concentrations and conditions.
abstract: The technical feasibility of using stopper-derived cork as an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions was evaluated in this study. Only 25 mg/L of cork powder was able to achieve 94 % of mercury removal for an initial mercury concentration of 500 μg/L. It was found that under the conditions tested, the efficiency of mercury removal expressed as equilibrium removal percentage does not depend on the amount of cork or its particle size, but is very sensitive to initial metal concentration, with higher removal efficiencies at higher initial concentrations. Ion exchange was identified as one of the mechanisms involved in the sorption of Hg onto cork in the absence of ionic competition. Under ionic competition, stopper-derived cork showed to be extremely effective and selective for mercury in binary mixtures, while in complex matrices like seawater, moderate inhibition of the sorption process was observed, attributed to a change in mercury speciation. The loadings achieved are similar to the majority of literature values found for other biosorbents and for other metals, suggesting that cork stoppers can be recycled as an effective biosorbent for water treatment. However, the most interesting result is that equilibrium data show a very rare behaviour, with the isotherm presenting an almost square convex shape to the concentration axis, with an infinite slope for an Hg concentration in solution around 25 μg/L.
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal. claudia.b.lopes@ua.pt.
authors.forename: Cláudia B
authors.initials: CB
authors.lastname: Lopes
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Joana R
authors.initials: JR
authors.lastname: Oliveira
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Rocha
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Daniela S
authors.initials: DS
authors.lastname: Tavares
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Silva
authors.affiliation: Corticeira Amorim, S.G.P.S., S.A.S, Paio de Oleiros, Santa Maria da Feira, Portugal.
authors.forename: Susana P
authors.initials: SP
authors.lastname: Silva
authors.affiliation: KWR Watercycle Research Institute, Nieuwegein, The Netherlands.
authors.forename: Niels
authors.initials: N
authors.lastname: Hartog
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Armando C
authors.initials: AC
authors.lastname: Duarte
authors.affiliation: Department of Chemistry/CESAM and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: E
authors.initials: E
authors.lastname: Pereira
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D008628:Mercury / Q000032:analysis / Q000737:chemistry*; D029963:Quercus; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
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