| Title |
Tuning charge density in tethered electrolyte active-layer membranes for enhanced ion-ion selectivity |
| ID_Doc |
10225 |
| Authors |
Porter, CJ; Wang, L; Zhong, MJ; Elimelech, M |
| Title |
Tuning charge density in tethered electrolyte active-layer membranes for enhanced ion-ion selectivity |
| Year |
2023 |
| Published |
|
| DOI |
10.1016/j.memsci.2022.121214 |
| Abstract |
Efforts toward developing membranes for aqueous separations beyond desalination have intensified, in attempts to achieve zero liquid discharge and a circular economy. Treatment of unconventional wastewaters and brines as well as recovery of valuable species require separation of solutes and ions. Recently, tethered electrolyte active-layer membranes (TEAMs) with dense ionizable brush polymers grafted from cellulose ultrafiltration supports were introduced as a robust, highly controllable membrane platform for these aqueous separations. In this study, we investigate crosslinking of single-block TEAMs to increase the effective charge density and coverage of pores by the active layer, and to possibly tap into size-based exclusion mechanisms. We also determine if crosslinking multiblock TEAMs comprising block copolymers of both negative and positive charge can better align blocks, thereby improving ion rejection. Single-block TEAMs with relatively short crosslinkers proved to have the highest divalent co-ion rejection in dilute solutions, at similar to 85-95%. NaCl was rejected similar to 55 and 80% by crosslinked negatively- and positively-charged TEAMs, respectively. Anion monovalent selectivity, Cl-/SO42-, was as high as similar to 25 for negative TEAMs, while the maximum Na+/Ca2+ ratio achieved by positive TEAMs was similar to 9.5. This work reinforces the value of ultrathin brush active-layer membranes and TEAMs as important tools to understand fundamental transport through membranes and better control synthesis for targeted selectivity. |
| Author Keywords |
Tethered-electrolyte active-layer membranes; Surface-initiated atom transfer radical; polymerization; Polyelectrolyte; Selectivity; Polymer brush |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:000978662800001 |
| WoS Category |
Engineering, Chemical; Polymer Science |
| Research Area |
Engineering; Polymer Science |
| PDF |
http://manuscript.elsevier.com/S0376738822009590/pdf/S0376738822009590.pdf
|