Flexible crystalline zinc doped silica nanofibers with superior wettability and remediation for oily wastewater

Abstract

Construction of ceramic fibrous membranes with good mechanical property and separation performance for the remediation of surfactant stabilized emulsions at high-temperature or complex environment is on great demand, yet still a challenge. Herein, the zinc ions doped silica (ZSO) nanofibrous membranes with expectable flexibility and superior selective wettability is prepared via a facile sol–gel electrospinning technique. The doping of zinc ions in silica nanofibers induced the obvious variation in crystalline and surface roughness structure, which were directly relevant to the mechanical properties and wettability of the resultant ZSO nanofibrous membranes. The advantageous features favored the ZSO membranes with excellent surfactant stabilized oil-in-water emulsion separation performance, including the separation efficiency of >98 %, the permeation flux of ∼3900 L m−2 h−1 driven by gravity, outstanding chemical stability, and good reusability within 10 cycles. In addition, the rationally designed micro-/nano-structured composite ceramic fibrous membranes displayed significant improvements on structural stability, mechanical property, and prominent separation performance towards emulsions at high temperature (∼95 °C) and nanoparticle-containing wastewater. The clarification of the relationship among crystalline structure, surface roughness, mechanical properties, and application performance would facilitate the fabrication of filtration materials used in the fields of oil-spill cleanup, seawater destination, and wastewater remediation.