Exfoliated boron nitride nanosheets/polyvinylidene fluoride composite membranes: A potential technique for efficient water-oil separation

Boron nitride nanosheets (BNNS) possess unique chemical, structural, and mechanical properties that make them attractive for applications such as dielectric systems, catalysis, energy storage and water treatment. However, challenges remain in efficiently exfoliating boron nitride (BN) and integrating it into polymer membranes to enhance their separation performance. This study addresses these challenges by exfoliating BN derived from the calcination of boric acid (B₂O₃) and urea (CO(NH₂)₂) under an inert nitrogen (N₂) atmosphere. The exfoliated BNNS were then incorporated into polyvinylidene fluoride (PVDF) to fabricate BNNS/PVDF composite membranes with amphiphilic surfaces via solution casting. The morphology of the exfoliated BN was confirmed using scanning electron microscopy (SEM), revealing nanosheets within the BN matrix. Raman spectroscopy showed a prominent peak at 1393 cm⁻¹ corresponding to the E₂g mode of BN, verifying that the structural integrity was maintained. X-ray diffractometer (XRD) analysis detected a significant peak at 2θ = 26°, characteristic of the (002) crystallographic plane of BN. Successful incorporation of BNNS into PVDF was demonstrated by SEM imaging of the composite membranes, which exhibited notable structural changes compared to pristine PVDF. A reduction in water contact angle indicated increased hydrophilicity, suggesting improved water-oil separation performance. These findings highlight the potential of BNNS/PVDF membranes in enhanced wastewater treatment applications. • Exfoliated BN nanosheets enhance PVDF membranes for water-oil separation. • BNNS/PVDF composites show improved hydrophilicity and membrane structure • Structural integrity of BNNS confirmed by SEM, Raman, and XRD analysis. • Amphiphilic BNNS/PVDF membranes offer promise for wastewater treatment.