Asymmetrically superwetting Janus Double-layer fabric for synchronous oil removal and catalytic reduction of aromatic dyes

Abstract

Effective synchronized removal of oils and aromatic dyes from wastewater is of great significance for environmental and water rehabilitation. Herein, cotton fabric was first grafted with polyaniline (PANI) nanofibers via a dilute solution polymerization to obtain Fabric@PANI. Utilizing the reversible oxidation-reduction property of PANI, the Fabric@PANI was in-situ oxidized to form superhydrophilic Fabric@PANI@Ag. Afterwards, the Fabric@PANI@Ag was post-modified with octadecanethiol (Thiol) to obtain the superhydrophobic/superoleophilic Fabric@PANI@Ag@Thiol. Notably, the PANI nanofibers as the activated anchored sites could uniformly and robustly immobilize Ag nanoparticles on the fabric. Moreover, a functional superwetting double-layer fabric (DL-Fabric) with asymmetric wettability that consisted of a top Fabric@PANI@Ag layer and a bottom Fabric@PANI@Ag@Thiol layer was prepared, on which immiscible oils can pass through both layers of the DL-Fabric and the water with soluble organic dyes can only wet the top layer. In addition, the water-soluble organic dyes can be reductive degradation using NaBH4 with the assistance of Ag catalysis, achieving simultaneous oil-removal (flux > 2.7 L m−2 s−1, oil rejection > 95%) and in situ catalytic reduction of aromatic dyes (0.01–0.02 M, efficiency > 99.2%). Thus, the versatile functionality of the fabric combined with its facile preparation strategy showed great potential applications in cost-effective water purification.