Separation performance of boron nitride nanotube stainless-steel filter

In this study, boron nitride nanotubes (BNNTs) were utilized as covering and reinforcing materials owing to their extraordinary insulation and extremely high hydrophobicity. The gas-liquid-solid annealing process was used to manufacture the BNNT stainless-steel filter, with a 120 mesh stainless steel filter serving as the substrate and B₂O₃ as the raw material. Scanning electron microscopy showed that the average diameter of the nanotubes was 0.40 μm. The BNNTs were bamboo shaped, and the BNNT stainless-steel filter was superhydrophobic, with a water contact angle was 150.49°. The materials demonstrated good separation performance, as indicated by the separation results obtained under four different test conditions (0 and 0.3 MPa, 3 and 10 mL/min). The solid-liquid separation effect of the BNNT stainless-steel filter was better than that of the Teflon filter. In oil-water separation experiments with varying water contents (1.2 and 5.8 wt%), the BNNT stainless-steel filter was more hydrophobic. Based on the results, the role of the hydrodynamic method in the separation of two superhydrophobic materials is discussed. The method introduced in this study can serve as a reference for the application of other filtration separation technologies. Furthermore, the superior separation performance of the superhydrophobic BNNT stainless-steel filter may enable the quick, effective, and continuous collection of water contaminated with oil, giving it a wide range of potential applications.