| Title |
Development of highly selective composite polymeric membranes for Li+/Mg2+ separation |
| ID_Doc |
17816 |
| Authors |
Saif, HM; Huertas, RM; Pawlowski, S; Crespo, JG; Velizarov, S |
| Title |
Development of highly selective composite polymeric membranes for Li+/Mg2+ separation |
| Year |
2021 |
| Published |
|
| DOI |
10.1016/j.memsci.2020.118891 |
| Abstract |
To meet the exponentially rising demand for lithium, it becomes vital to develop environmentally friendly processes for its recovery from brines, salt lakes and/or seawater. In this work, novel composite lithium transport selective polymeric membranes were developed to separate lithium and magnesium ions. Hydrogen manganese oxide (HMO) (at weight percentage from 0 to 25%), polystyrene sulfonate sodium salt (PSS-Na) and lithium triflate (LiCF3SO3) were added into the sulfonated polyethersulfone (SPES) matrix to prepare composite membranes. The developed membranes showed high mechanical stability and a homogeneous distribution of HMO. The most promising membrane, containing 20% (w/w) of HMO, showed an almost 13 times higher Li+ ionic conductivity (8.28 mS/cm) compared to the control composite membrane (without HMO) and an average ideal selectivity of 11.75 for the Li+/Mg2+ pair. The composite-20% membrane had the lowest intermolecular distance between the polymer chains (according to X-ray diffraction (XRD) analysis), the most flexible structure (lowest T-g) and showed the homogeneous dispersion of HMO (SEM images), which explains its highest Li+ /Mg2+ selectivity among the tested membranes. The lithium ion transport performance and separation efficiency were investigated through diffusion dialysis experiments, under different operating conditions. A binary separation factor of 9.10 for Li+/Mg2+ and Li+ molar flux of 0.026 mol/(m(2).h) was achieved without applying any external potential difference. When an external potential difference of 0.2 V was applied, the binary separation factor of Li+/Mg2+ pair was 5, while the Li+ molar flux increased almost 5 times. The obtained results provide the basis to design and develop composite lithium transport selective polymeric membranes, thus representing a promising step for future implementation of such membranes to recover lithium from saline streams. |
| Author Keywords |
Lithium recovery; Composite membranes; Lithium ion sieves (LIS); Sea mining; Diffusion dialysis |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:000609144000005 |
| WoS Category |
Engineering, Chemical; Polymer Science |
| Research Area |
Engineering; Polymer Science |
| PDF |
https://run.unl.pt/bitstream/10362/111897/1/post_print_Saif_et_al_JMS_620_2021_11889.pdf
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