| Title |
Phosphorus recovery by Donnan dialysis: Membrane selectivity, diffusion coefficients, and speciation effects |
| ID_Doc |
25847 |
| Authors |
Shashvatt, U; Amurrio, F; Portner, C; Blaney, L |
| Title |
Phosphorus recovery by Donnan dialysis: Membrane selectivity, diffusion coefficients, and speciation effects |
| Year |
2021 |
| Published |
|
| DOI |
10.1016/j.cej.2021.129626 |
| Abstract |
Donnan dialysis occurs when an electrochemical potential gradient exists for ions on either side of an ionexchange membrane. We posit that this phenomenon can be leveraged to develop a sustainable process for nutrient recovery from wastewater. In this work, we conducted a fundamental study of the key parameters that control orthophosphate (P(V)) removal and recovery by Donnan dialysis. First, a new variable, namely the minimum draw ion concentration ratio between the draw and waste solutions (Rd/w), was established as the principal design parameter for Donnan dialysis. Then, the following variables were evaluated for their effects on P(V) removal and recovery: waste solution composition; draw anion type and concentration; and, membrane selectivity, thickness, and hydration. The waste solution pH controlled P(V) sorption to the anion-exchange membrane, with HPO42- exhibiting a higher affinity than H2PO4- . For an Rd/w of 10, 90.7% of H2PO4- and 98.4% of HPO42- were removed from a 10 mM P(V) waste solution using 100 mN and 218 mN NaCl draw solutions, respectively. The P(V) removal efficiency was dependent on draw solution concentration, and 77.1%, 95.3%, and 98.4% HPO42- removal was achieved with 48 (Rd/w = 2), 115 (Rd/w = 5), and 218 mM (Rd/w = 10) NaCl draw solutions, respectively. The rate of P(V) recovery was faster with HCOO- draw anions than with Cldue to (i) the higher separation factor for P(V) over HCOO- (7.28) compared to Cl- (1.27) and (ii) the greater extent of membrane hydration with HCOO- draw solutions. Overall, this work established a new design parameter (Rd/w) and applied that parameter to optimize the draw solution chemistry for phosphorus recovery by Donnan dialysis. |
| Author Keywords |
Donnan dialysis; Phosphorus; Ion exchange; Nutrient recovery; Circular economy; Resource recovery |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:000663704900006 |
| WoS Category |
Engineering, Environmental; Engineering, Chemical |
| Research Area |
Engineering |
| PDF |
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