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Published on: January 7, 2019
Pharmaceutical retention mechanisms by nanofiltration membranes
Long D Nghiem1, Andrea I Schäfer, Menachem Elimelech
1Environmental Engineering, University of Wollongong, New South Wales 2522, Australia.
Environmental Science & Technology
|October 26, 2005
Summary
Nanofiltration (NF) membrane retention of pharmaceuticals like sulfamethoxazole, carbamazepine, and ibuprofen depends on membrane type and molecule properties. Retention is governed by size exclusion for tight membranes and electrostatic repulsion plus size exclusion for loose membranes.
Area of Science:
- Environmental Science
- Chemical Engineering
- Materials Science
Background:
- Pharmaceuticals are emerging contaminants in water.
- Nanofiltration (NF) is a promising technology for removing pharmaceuticals.
- Understanding retention mechanisms is crucial for effective NF process design.
Purpose of the Study:
- Investigate retention mechanisms of sulfamethoxazole, carbamazepine, and ibuprofen by NF membranes.
- Relate pharmaceutical retention to membrane characteristics, molecular properties, and solution chemistry.
- Determine the influence of pH and molecular properties on pharmaceutical removal.
Main Methods:
- Laboratory-scale nanofiltration experiments.
- Utilized two well-characterized NF membranes (tight and loose).
- Analyzed retention based on membrane properties, pharmaceutical physicochemical characteristics, and solution chemistry.
Main Results:
- Tight NF membrane retention is dominated by steric exclusion.
- Loose NF membrane retention involves both electrostatic repulsion and steric exclusion.
- Ionizable pharmaceuticals show pH-dependent retention, with higher retention for ionized forms.
- Hydrophobicity and polarity significantly influence retention of uncharged pharmaceuticals.
Conclusions:
- Pharmaceutical retention by NF membranes is complex, depending on membrane type and molecular properties.
- Electrostatic interactions and steric hindrance are key mechanisms, especially for ionizable compounds.
- Physicochemical properties like hydrophobicity and polarity are critical for predicting retention, particularly for neutral species.
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