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Forward osmosis (FO) has primarily been explored for applications in water desalination. While FO has also shown potential in concentrating dairy products, little to no attention has been paid to its potential in concentrating biotherapeutics, particularly to the very high concentrations needed for many monoclonal antibody products that are delivered by subcutaneous injection. This study demonstrates the feasibility of using FO as an alternative to ultrafiltration (UF) to achieve highly concentrated protein formulations using human Immunoglobin G (hIgG) as a model protein. The permeate flux in FO, using 1 M NaCl as the draw solution, decreased with increasing hIgG concentration due primarily to concentration polarization effects that are strongly influenced by the increase in feed viscosity for the concentrated hIgG solution. The importance of the hIgG viscosity on the FO performance was demonstrated by performing experiments with concentrated polyethylene glycol solutions and through mathematical modeling that accounts for the effects of both external and internal concentration polarization on FO performance. Batch concentration experiments with FO achieved final hIgG concentrations greater than 290 g/L compared to a maximum achievable concentration in UF of approximately 150 g/L. These results clearly demonstrate the potential of using FO, with high osmotic pressure draw solutions, to achieve highly concentrated formulations of therapeutic proteins that are beyond the capability of current UF processes.
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This content will become publicly available on July 29, 2026
Functionalized Magnetic Nanoparticles as Recyclable Draw Solutes for Forward Osmosis: A Sustainable Approach to Produced Water Reclamation
Magnetic nanoparticles (MNPs), especially iron oxide (Fe3O4), display distinctive superparamagnetic characteristics and elevated surface-area-to-volume ratios, facilitating improved physicochemical interactions with solutes and pollutants. These characteristics make MNPs strong contenders for use in water treatment applications. This research investigates the application of iron oxide MNPs synthesized via co-precipitation as innovative draw solutes in forward osmosis (FO) for treating synthetic produced water (SPW). The FO membrane underwent surface modification with sulfobetaine methacrylate (SBMA), a zwitterionic polymer, to increase hydrophilicity, minimize fouling, and elevate water flux. The SBMA functional groups aid in electrostatic repulsion of organic and inorganic contaminants, simultaneously encouraging robust hydration layers that improve water permeability. This adjustment is vital for sustaining consistent flux performance while functioning with MNP-based draw solutions. Material analysis through thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) verified the MNPs’ thermal stability, consistent morphology, and modified surface chemistry. The FO experiments showed a distinct relationship between MNP concentration and osmotic efficiency. At an MNP dosage of 10 g/L, the peak real-time flux was observed at around 3.5–4.0 L/m2·h. After magnetic regeneration, 7.8 g of retrieved MNPs generated a steady flow of ~2.8 L/m2·h, whereas a subsequent regeneration (4.06 g) resulted in ~1.5 L/m2·h, demonstrating partial preservation of osmotic driving capability. Post-FO draw solutions, after filtration, exhibited total dissolved solids (TDS) measurements that varied from 2.5 mg/L (0 g/L MNP) to 227.1 mg/L (10 g/L MNP), further validating the effective dispersion and solute contribution of MNPs. The TDS of regenerated MNP solutions stayed similar to that of their fresh versions, indicating minimal loss of solute activity during the recycling process. The combined synergistic application of SBMA-modified FO membranes and regenerable MNP draw solutes showcases an effective and sustainable method for treating produced water, providing excellent water recovery, consistent operational stability, and opportunities for cyclic reuse.
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- PAR ID:
- 10621085
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Separations
- Volume:
- 12
- Issue:
- 8
- ISSN:
- 2297-8739
- Page Range / eLocation ID:
- 199
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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