Hydranal composite 5

The material was ground and sieved using a mortar grinder (Fritsch, Pulverisette 2) and a vibratory sieve shaker (Fritsch, Analysette 3). The goethite was digested using a microwave digester (8 positions, Milestone). The metal content of the digested samples was measured via inductively coupled plasma optical emission spectroscopy (ICP-OES), Optima 3000DV from PerkinElmer. The metal content of all the PLSs was determined via ICP-OES, Optima 8300 from PerkinElmer, with the exception of the screening experiments for DES selection, where the metal content of the different samples was measured using a portable benchtop Bruker Total Reflection X-ray Fluorescence (TXRF) Spectrometer S2 Picofox. An Eppendorf 5804 centrifuge was used to facilitate the phase separation. X-ray powder diffraction (XRD) was used for the phase identification of the crystalline fraction (Bruker D2 Phaser). The quantitative XRDs were performed with a PANalytical EMPYREAN system operated at 40 kV and 45 mA, with a cobalt anode and equipped with a BBHD (Bragg Brentano High Definition) and a 3D detector (PIXcel 3D) with an active scanning length of 3.347° 2θ. The water content of the DESs was measured using a Mettler-Toledo V30S KF titrator where HYDRANAL™ – Composite 5, and HYDRANAL™ – Methanol dry (Honeywell, Fluka) were used as titrant and medium, respectively.