The concentration of metals was determined using an inductively coupled plasma-optical emission spectroscopy (ICP-OES, 7500CS, Agilent Technologies, USA). Before analysis, each sample was diluted using 5% nitric acid (Suprapur, Sigma-Aldrich, Australia) to ensure their elemental components remain in solution. Before each batch of analysis, detector calibration was performed electronically followed by wavelength calibration using a multi-element wavelength calibration solution. Different dilutions of the standard solutions were prepared to obtain a calibration curve (R 2 >0.99). Solution pH and conductivity were measured using an Orion 4-Star Plus pH/conductivity meter (Thermo Scientific, USA). Change in membrane properties (i.e., membrane hydrophobicity) after filtration was analysed by measuring the contact angle using a goniometer (Rame-Hart, USA).
The recovered crystals of lithium carbonate were characterised using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) (JSM-6490, JEOL, Japan). The purity of the crystals was verified using X-ray diffraction (XRD) spectrum (GBC MMA, USA) at diffraction angles (2θ) ranging from 5 to 90° with a stepwise increase of 0.02° using Cu-Kα radiation at 40 kV and 150 mA.
The recovered crystals of lithium carbonate were characterised using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) (JSM-6490, JEOL, Japan). The purity of the crystals was verified using X-ray diffraction (XRD) spectrum (GBC MMA, USA) at diffraction angles (2θ) ranging from 5 to 90° with a stepwise increase of 0.02° using Cu-Kα radiation at 40 kV and 150 mA.