Renewable superhydrophobic PVB/SiO2 composite membranes with self-repairing for high-efficiency emulsion separation

Design and constructing high performance filtration membranes for oil purification from emulsified oil/water mixtures with good durability and self-healing property is highly desired for the remediation of oily wastewater and oil recycling caused by oil leakage and oil spill, but remain a tough challenge. Herein, a facile and environmentally friendly method for fabricating dodecyltrichlorosilane grafted polyvinyl butyral/silica sol/silica nanoparticles composite nanofibrous microfiltration membranes is developed. The as-prepared nanofibrous membranes exhibited intriguing wetting behaviors, such as superhydrophobicity in air and under oil, small sliding angle, and extremely low adhesion force. The superwettability, hierarchical porous structure, and good mechanical properties endowed the membranes with fascinating emulsion separation performance towards highly emulsified oil/water mixtures, involving high separation efficiency >99.6%, large oil permeation flux of similar to 2316.2 L m(-2) h(-1), and excellent long-term cyclic performance in 10 cycles. Additionally, the as-prepared nanofibrous membranes exhibited superior self-healing performance against external force and maintained good emulsion separation performance after 10 abrasion-repairing cyclic processes. The successful fabrication of such nanofibrous membranes provides a versatile strategy for developing materials with high purification per-formance, good repairability, and excellent durability for the oily wastewater remediation, oil spill clean-up, and oil purification.

Automated summary

In this study, a facile and environmentally friendly method was developed to fabricate dodecyltrichlorosilane grafted polyvinyl butyral/silica sol/silica nanoparticles composite nanofibrous microfiltration membranes, which exhibited superhydrophobicity, low adhesion force, and self-healing property. The membranes showed excellent emulsion separation performance, with high separation efficiency, large oil permeation flux, and long-term cyclic performance.