Comprehensive Study of Physicochemical Properties in Poly-(Vinylidene Fluoride) Membranes Loaded with OPEFB's Lignin/ Lignosulfonate via Phase Inversion

The development of membrane technology is rapidly advancing, such as hydrophilic PVDF membranes, which provide anti-fouling properties to the membrane. Therefore, this research innovates the development of hydrophilic PVDF membranes by incorporating lignin-lignosulfonate fillers from OPEFBs in situ. This study successfully prepared hybrid PVDF membranes using the phase inversion method. ATR-FTIR, XRD, and TGA/DSC analyses confirmed that the addition of 2 % filler promoted the formation of the beta-phase in PVDF, which was more dominant than with the addition of 4 % filler, especially in the PLs2 % membrane. SEM images of the membranes showed an asymmetric structure with finger-like and sponge-like pores. Interactive 3D surface imaging demonstrated increased pore potential peaks when lignosulfonate was added compared to lignin. The addition of 4 % filler had a hydrophilic-hydrophobic repelling effect, increasing the porosity and water absorption of the PL4 % and PLs4 % membranes. Phase inversion membranes were relatively hydrophilic with a water contact angle of 61 degrees, and adding filler reduced the membrane's contact angle by 8 degrees. Based on the obtained results, it can be concluded that PVDF hybrid membranes with lignin and lignosulfonate fillers have significant potential for development in membrane technology applications that require hydrophilic membranes, such as wastewater treatment and seawater desalination. PVDF membranes are synthesized via phase inversion, integrating lignin/lignosulfonate fillers. This process prompts the fillers to align with the membrane surface during liquid-liquid demixing, enhancing the dominance of the beta phase by aligning the C-F groups of PVDF. The incorporation of these fillers, particularly at PLs4%, significantly boosts beta-phase formation, ensuring a homogeneous structure. . image