• Novel adsorptive membranes were fabricated by incorporating PEG-grafted phosphoric acid-modified boron nitride (PEG-g-PA/BN) into PVDF via melt blending and phase inversion, achieving enhanced arsenic removal.
• The 93:7 BN membrane exhibited the highest arsenic adsorption capacity, attributed to complexation between arsenic ions and PA/BN within the PVDF matrix.
• Increasing PEG-g-PA/BN content reduced water flux and porosity but improved anti-fouling resistance and solute rejection, balancing permeability and adsorption performance.
• The study demonstrates a scalable method for producing functionalized boron nitride-based adsorptive membranes for efficient heavy metal removal in wastewater treatment.