Dually Prewetted Underwater Superoleophobic and under Oil Superhydrophobic Fabric for Successive Separation of Light Oil/Water/Heavy Oil Three-Phase Mixtures

Abstract

Remediation of oil spills requires new technologies to separate light oil/water/heavy oil mixtures. Low-cost, biological, and environmentally friendly materials are needed to treat water pollution caused by oils. In this study, a corn straw powder (CSP)-coated fabric (CSPF) was fabricated by spraying waste CSP and polyurethane onto amphiphilic cotton fabric, and thus, the wettability of CSPF is enhanced by taking advantage of the hierarchical structure and increased surface roughness. Therefore, the CSPF could be dually prewetted (DCSPF) with both water and oil, and it showed underwater superoleophobic and under oil superhydrophobic properties without any further chemical modification. When applied to light oil/water/heavy oil separation, the DCSPF could be used to successively separate light oil/water/heavy oil three-phase mixtures under gravity with a high separation efficiency and flux. In addition, the DCSPF showed excellent structural and chemical stability according to repeated cycling and corrosive solution/oil separation experiments. The results of this study are of value in providing a simple, low-cost, and environment-friendly approach for application in the field of successive separation of light oil/water/heavy oil three-phase mixtures.

Mussel‐Inspired Dual‐Superlyophobic Biomass Membranes for Selective Oil/Water Separation

“…The oil content in filtrates were in the range of 12.9 ± 4.9 ppm ( o ‐xylene, XYL) to 43.7 ± 5.1 ppm (TOL), and water content was in the range of 37.3 ± 1.4 ppm (for CTC/water mixture) to 130.1 ± 2.4 ppm (for CF/water mixture) (Figure 9H; Figure S9, Supporting Information). The simple preparation as well as high performance in flux and separation efficiency of the membranes are competitive to other dual‐superlyophobic membranes previously reported (Table S1, Supporting Information) 9,11,29,32c,38. More interestingly, the dual‐superlyophobic membranes show effective separation for both oil‐in‐water and water‐in‐oil emulsions.…”

“…These results demonstrate that infused water or oil layers are stable enough such that the counterpart phase (oil or water) can hardly reach the solid surface. Therefore, the membranes feature excellent repellency and antifouling ability toward both oil and water, resulting in the dual‐superlyophobic behavior . Also important is that the wettability of both cotton@PDA and KP@PDA can be easily switched between underoil superhydrophobicity and underwater superoleophobicity via drying and prewetting by the corresponding membrane infusion liquid.…”

“…The separation is driven by gravity. Liquid flux is calculated by the following equation where F (L m −2 h −1 ) is the flux, V is the volume of liquid passing through the membrane, A is working area of the membranes, and t is permeation time.…”

Development of One‐Step Water‐Repellent and Flame‐Retardant Finishes for Cotton

“…Both of nano‐ and micro‐hierarchical surface roughness and low surface energy are recognized as strong heuristic to accomplish superhydrophobic property, which is a key role to produce waterproof fabrics. Nonetheless, low surface energy modifiers are commonly fluorine‐based materials which are highly toxic and expensive, which led to limiting its wider applications …”

Fabrication of Green Superhydrophobic/Superoleophilic Wood Flour for Efficient Oil Separation from Water

“…Due to their remarkable waterproofing performance, superhydrophobic materials have been prepared through various approaches, involving a sol-gel process [19], vapor phase deposition [20], chemical etching [21,22], surface fluorination [23] and electrospinning [24]. To date, a number of advanced materials with superhydrophobic and superoleophilic properties have been synthesized and applied to the disposal of spilled oil [25][26][27][28][29]. For example, Wang et al [30] developed a facile electrochemical deposition method to prepare a novel functional micro-nano hierarchical structured copper mesh film with special superhydrophobic and superoleophilic characteristics for the effective removal of oil from water.…”