Ultrathin pH-sensitive nanoporous membranes for superfast size-selective separation

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Stimuli-responsive nanoporous membranes are crucial for tunable separation processes.
• Existing membranes often lack sensitivity or efficient fabrication methods.

Purpose of the Study:

• To develop novel ultrathin, pH-sensitive nanoporous membranes.
• To investigate their fabrication via self-assembly and evaluate their separation performance.

Main Methods:

• Fabrication of membranes through the self-assembly of poly(acrylic acid) (PAA) with metal hydroxide nanostrands.
• Characterization of membrane thickness, pore size, and pH-dependent permeation/rejection properties.
• Testing water flux and rejection across a range of pH values.

Main Results:

• Successfully fabricated ultrathin (28 nm) PAA-based nanoporous membranes.
• Achieved ultrafast water permeation (3740 L m⁻¹ h⁻¹ bar⁻¹) and good rejection.
• Demonstrated significant pH-sensitivity, with a sharp decrease in water flux around pH 5.0.

Conclusions:

• The developed membranes offer a promising platform for pH-responsive separation.
• Their ease of fabrication and tunable properties suggest broad applicability.
• Potential uses include controlled release systems and advanced size- and charge-selective separations.