Nanofibrous microfiltration membrane based on cellulose nanowhiskers

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Water Treatment

Background:

• Developing advanced microfiltration (MF) membranes with high flux, low pressure drop, and superior retention is crucial for water purification.
• Existing membranes often face limitations in balancing these properties, particularly for removing diverse microbial contaminants like bacteria and viruses.
• Nanomaterials offer unique properties for enhancing membrane performance, but their integration requires careful design and fabrication.

Purpose of the Study:

• To engineer a multilayered nanofibrous MF membrane system by incorporating cellulose nanowhiskers into an electrospun scaffold.
• To achieve high flux, low pressure drop, and effective retention of bacteria and bacteriophages.
• To investigate the impact of cellulose nanowhisker loading on pore size, surface charge, and overall membrane performance.

Main Methods:

• Fabrication of a multilayered membrane using electrospun polyacrylonitrile (PAN) nanofibers on a poly(ethylene terephthalate) (PET) substrate.
• Impregnation of ultrafine cellulose nanowhiskers (CNWs) onto the PAN nanofiber surface to create a cross-linked nanostructured mesh.
• Characterization of membrane properties including pore size, surface charge (zeta potential, conductivity titration), mechanical strength, and filtration performance against bacteria and bacteriophages.

Main Results:

• The developed CNW-based MF membrane exhibited a high surface-to-volume ratio and a negatively charged surface.
• Mean pore size and distribution were tunable by adjusting CNW loading, resulting in good mechanical properties and high surface charge density.
• The membrane demonstrated significantly higher adsorption capacity for a model dye compared to commercial membranes and achieved full retention of bacteria (E. coli, B. diminuta; LRV > 6) and decent retention of bacteriophage MS2 (LRV > 2).

Conclusions:

• The cellulose nanowhisker-impregnated nanofibrous membrane represents a promising advancement in microfiltration technology.
• This system effectively balances high flux, low pressure drop, and robust retention capabilities for microbial contaminants.
• The tunable nature and enhanced adsorption properties of the CNW-based membrane offer significant potential for water treatment applications.