Sustainable and scalable development of PVDF-OH Ag/TiOx nanocomposites for simultaneous oil/water separation and pollutant degradation

Abstract

Freshwater scarcity is a persistent global problem and is frequently worsened by contamination with oils and oil-soluble contaminants. Although the technological union of microfiltration membranes and pollutant-degrading nanoparticles are up-and-coming solutions to eliminate oils from the aquatic environment, an utterly sustainable production process enabling the transfer of these materials close to reality has not been presented so far. Here, for the first time, electrospinning and reactive laser ablation in liquids (RLAL) are combined to prepare a set of chemically stable PVDF-based membranes through a process with a favorable sustainability footprint and endowing all the features for production scale-up. The most efficient reclamation of purified water from oily wastewater was found with the membranes decorated with 2.2 wt% Ag/TiO_x nanoparticles in an alkaline solution. The entire recovery process takes place in ultra-short contact times (∼0.3 s), while beyond 58% of an organic pollutant (4-nitrophenol) and 80% of a tight oil emulsion (n-hexane in water) can be degraded and separated, respectively, in a continuous 20-min gravity-driven filtration. Thus, these findings provide a groundwork for the sustainable and scalable development of advanced nanotechnology for cleansing oily polluted water.