PVDF/Ag@SiO2 nanofiber membranes with surface substructure for dye catalytic degradation and oil-water separation

Abstract

Background

Effective removal of oils and aromatic dyes from water is of critical, global importance for environmental and water remediation. Developing multifunctional membrane materials capable of both oil-water separation and in-situ catalytic degradation offers a promising, efficient, and environmentally friendly solution to this challenge.

Methods

In this study, Ag@SiO₂ nanoparticles with a high specific surface area and catalytic activity were successfully synthesized. These nanoparticles were loaded onto electrospun PVDF nanofiber membranes using physical deposition. To enhance the number of active sites on Ag@SiO₂, groove substructures were introduced into the PVDF nanofiber membranes during electrospinning. This modification resulted in nanofiber membranes exhibiting superhydrophilicity and underwater superoleophobicity.

Significant findings

The resulting PVDF nanofiber membranes demonstrated high water flux (1151.99 L/m²/h) and excellent oil-water separation performance (>99 %) under self-weight. Additionally, in the presence of NaBH₄, the organic dye methylene blue (MB) underwent complete catalytic degradation within 4 min, with a first-order degradation rate constant of 0.567 min^-1. After ten cycles, the nanofiber membranes retained over 90 % of their catalytic efficiency, indicating long-term operational stability. These nanofiber membranes offer a novel strategy for efficient oil-water separation and water purification.