Modeling the antifouling properties of atomic layer deposition surface-modified ceramic nanofiltration membranes

Abstract

This work investigates the enhancement of antifouling properties of ceramic nanofiltration membranes by surface modification via atomic layer deposition (ALD) of TiO₂. Feed solutions containing bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA) were used as model foulants. The classic fouling mechanism models and the modified fouling indices (MFI) were deduced from the flux decline profiles. Surface roughness values of the ALD coated and uncoated membranes were 63 and 71 nm, respectively, while the contact angles were 34.2 and 59.5°, respectively. Thus, coating increased the water affinity of the membrane surfaces and consequently improved the anti-fouling properties. The MFI values and the classic fouling mechanism correlation coefficients for cake filtration for the ALD coated and the uncoated membrane upon SA fouling were 42,963 (R² = 0.82) and 143,365 sL⁻² (R² = 0.98), respectively, whereas the correlation coefficients for the combined foulants (SA + BSA + HA) were 267,185 (R² = 0.99) and 9569 sL⁻² (R² = 0.37), respectively. The study showed that ALD can effectively enhance the antifouling properties of ceramic membranes.

Graphical Abstract

Keywords:

• Atomic layer deposition
• ceramic membranes
• fluorescence spectroscopy
• modified fouling index
• molecular weight cut off
• surface modification

Acknowledgements

The University of South Africa (UNISA) and the National Research Foundation (NRF) are acknowledged for their financial support. The Technical University of Delft (TU Delft) is acknowledged for training in ALD and membrane technology.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

The author(s) reported there is no funding associated with the work featured in this article.