Highly Efficient and Flexible Electrospun Carbon–Silica Nanofibrous Membrane for Ultrafast Gravity-Driven Oil–Water Separation

Abstract

A novel free-standing and flexible electrospun carbon-silica composite nanofibrous membrane is newly introduced. The characterization results suggest that the electrospun composite nanofibers are constructed by carbon chains interpenetrated through a linear network of 3-dimensional SiO2. Thermogravimetric analysis indicates that the presence of insulating silica further improve the thermal resistance of the membrane. Additionally, the mechanical strength test shows that the membrane's toughness and flexibility can be enhanced if the concentration of SiO2 is maintained below 2.7 wt %. Thermal and chemical stability test show that the membrane's wettability properties can be sustained at an elevated temperature up to 300 °C and no discernible change in wettability was observed under highly acidic and basic conditions. After surface-coating with silicone oil for 30 mins, the composite membrane exhibits ultra-hydrophobic and superoleophilic properties with water and oil contact angles being 144.2 ± 1.2° and 0°, respectively. The enhanced flexibility and selective wetting property enables the membrane to serve as an effective substrate for separating free oil from water. Lab-scale oil-water separation test indicates that the membrane possesses excellent oil-water separation efficiency. In addition, its inherent property of high porosity allows oil-water separation to be performed in a gravity-driven process with high-flux. We anticipate that this study will open up a new avenue for fabrication of free-standing carbonaceous composite membrane with tunable flexibility for energy efficient and high-throughput production of clean water.

Recent Progress of Polyurethane-Based Materials for Oil/Water Separation

“…[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] Commonly, the mechanical property of electrospun¯ber would decrease after absorption of the oil. Due to the good elastic and mechanical properties, electrospun PU membranes have practical application in oil/water separation.…”

Applications of nanotechnology in oil and gas industry: Progress and perspective

“…Improve rock surface property for flooding applications Nanomembrane Drilling/Completion Production Refining 1. Enhance separation of gas streams and removal of impurities from oil and gas streams Li et al, [23] Tai et al, [24] Khalilpour et al [25] 2. Remove small suspended oil particles and dissolved elements 3.…”

“…In addition to nanofiltration in wastewater treatment, nanomembranes play an important role in oil/water separation, including purifying oil, enhancing gas separation, and CO 2 capture and storage. [23][24][25] A micro/nano dual-scaled porous nitrocellulose (NC) membrane was fabricated and it showed high efficiency of oil/water separation. [81] In comparison to "oil-removing" types of materials, the "water-removing" membranes with underwater superoleophobicity can avoid fouling or even blocking by oils due to their oleophilic characteristics, and it can rapidly separate water from a variety of oil/water mixtures including hexane, petroleum ether, and crude oil.…”

A Hierarchically-Nano Structured TiO2-Carbon Nanofibrous Membrane for Concurrent Gravity-Driven Oil-Water Separation

“…1f), the membrane can be bended at an angle of 90° without loss of structural integrity. This phenomenon can be attributed to the entanglement of the continuous and flexible carbon-silica nanofibers [25]. To further examine the wettability of the as-fabricated membrane, the spreading process of a water droplet is recorded by a VCA instrument operated in dynamic mode at a capture speed of 30 frames per second.…”