Preparation of hydrophilic and antibacterial bifunctional PVDF ultrafiltration membrane based on pomegranate peel powder

Pomegranate peels are often regarded as waste products, despite its antibacterial properties and hydrophilic functional groups. In this work, varying concentrations (0, 0.05, 0.15, 0.2 and 0.5 wt%) of pomegranate peel powder (PPP) were doped into polyvinylidene fluoride (PVDF) ultrafiltration membranes (UF) as antimicrobial agents and hydrophilic modifiers. With increase in PPP concentration, the water contact angle (from 83° to 66°) and porosity (from 73% to 54%) of the membrane showed a decrease, while the water flux, mechanical strength, and elongation at break had a consistent pattern of first increase followed by subsequent decrease. The morphological characteristics, chemical composition and thermodynamic properties of the membranes were further analyzed by SEM, FTIR, TAG, and DSC respectively. Additionally, in comparison to the PVDF pure membrane, membranes containing PPP demonstrated a more pronounced inhibitory impact on E. coli, and when the concentration was 0.15 wt% (M2), the BSA rejection rate (93.72%) and water flux (734.7 L m−2 h−1) of the membrane reached the peak. In conclusion, this study proposes the consideration of a cost-effective, environmentally friendly UF membrane with hydrophilic and antibacterial dual function, highlighting the promising application of pomegranate peel as agricultural waste in the membrane industry.