title: Modification of the surface of activated carbon electrodes for capacitive mixing energy extraction from salinity differences.
abstract: The "capacitive mixing" (CAPMIX) is one of the techniques aimed at the extraction of energy from the salinity difference between sea and rivers. It is based on the rise of the voltage between two electrodes, taking place when the salt concentration of the solution in which they are dipped is changed. We study the rise of the potential of activated carbon electrodes in NaCl solutions, as a function of their charging state. We evaluate the effect of the modification of the materials obtained by adsorption of charged molecules. We observe a displacement of the potential at which the potential rise vanishes, as predicted by the electric double layer theories. Moreover, we observe a saturation of the potential rise at high charging states, to a value that is nearly independent of the analyzed material. This saturation represents the most relevant element that determines the performances of the CAPMIX cell under study; we attribute it to a kinetic effect.
authors.affiliation: Dipartimento di Scienze della Salute, Università degli Studi di Milano - Bicocca, via Cadore 48, Monza (MB) 20900, Italy. Electronic address: massimo.marino@unimib.it.
authors.forename: M
authors.initials: M
authors.lastname: Marino
authors.affiliation: Dipartimento di Scienze della Salute, Università degli Studi di Milano - Bicocca, via Cadore 48, Monza (MB) 20900, Italy. Electronic address: lorenza.misuri@unimib.it.
authors.forename: L
authors.initials: L
authors.lastname: Misuri
authors.affiliation: Department of Applied Physics, School of Sciences, University of Granada, 18071 Granada, Spain. Electronic address: jimenezo@ugr.es.
authors.forename: M L
authors.initials: ML
authors.lastname: Jiménez
authors.affiliation: Department of Applied Physics, School of Sciences, University of Granada, 18071 Granada, Spain. Electronic address: sahualli@ugr.es.
authors.forename: S
authors.initials: S
authors.lastname: Ahualli
authors.affiliation: MAST Carbon International Ltd. of Jays Close, Basingstoke, Hampshire RG22 4BA, United Kingdom. Electronic address: kozynch@mastcarbon.co.uk.
authors.forename: O
authors.initials: O
authors.lastname: Kozynchenko
authors.affiliation: MAST Carbon International Ltd. of Jays Close, Basingstoke, Hampshire RG22 4BA, United Kingdom. Electronic address: steve.tennison@mastcarbon.co.uk.
authors.forename: S
authors.initials: S
authors.lastname: Tennison
authors.affiliation: Politechnika Wrocklawska, Wybrzéze Wyspiánskiego 27, 50-370 Wrocław, Poland. Electronic address: marek.bryjak@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Bryjak
authors.affiliation: Dipartimento di Scienze della Salute, Università degli Studi di Milano - Bicocca, via Cadore 48, Monza (MB) 20900, Italy. Electronic address: dbrogioli@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Brogioli
keywords: Capacitive mixing; Electric double layer; Energy from salinity difference; Gouy–Chapman–Stern model; Surface groups