Fabrication of a Bi₂O₃ Surface-Modified Polyvinylidene Fluoride Membrane via an Ultraviolet Photografting Method: Improving Hydrophilicity and Degree of Acrylic Acid Grafting

Abstract

In this study, a superior hydrophilic polyvinylidene fluoride (PVDF) membrane with an enhanced monomer grafting ratio was prepared via an ultraviolet (UV) photografting polymerization method. The water contact angle (WCA) of the Bi 2 O 3 −acrylic acid (AA)-modified PVDF membrane reduces to 40.4°with the increasing of Bi 2 O 3 content, illustrating significant enhancement of membrane hydrophilicity. Attenuated total reflection Fourier transform infrared spectra and atomic absorption spectroscopy reveal that Bi 2 O 3 −AA-modified membranes have more than five times AA grafting degree onto the surface of the hydrophobic PVDF membranes than only the AA-modified membrane. The mechanism of Bi 2 O 3 promoting degree of AA grafting during the polymerization process is also especially explored in this research, and h + and • O 2 − are proved to be primary active species in graft polymerization. Unexpectedly, the modified membrane has much better retention performance compared with the neat membrane. In addition, the Bi 2 O 3 −AA modified membrane also shows self-cleaning property for degradation dyes on the membrane surface.

Highly Efficient Oxygen-Activated Self-Cleaning Membranes Prepared by Grafting a Metal–Organic Framework-Derived Catalyst

“…ROS Identification. As studies have shown that the catalytic oxidation of organic dyes depends strongly on the action of highly reactive ROS that may be generated by oxygen activation, 38 radical scavenging experiments were combined with EPR spintrapping techniques in this study to detect ROS formed during the process of catalytic oxidation. TBA (100 mM), p-BQ (10 mM), and L-histidine (50 mM) were used as scavengers of •OH, •O 2 − , and 1 O 2 , respectively, 57 to determine the relative contributions of different ROS to the catalytic degradation of pollutants.…”

“…The CuNi–C grafting process is illustrated in Scheme and includes PVDF membrane surface carboxylation, catalyst handling and deposition, and thermal cross-linking. , PVDF membranes were ultrasonically cleaned with an ethanol–water solution to remove surface impurities and adhered organic contaminants and subsequently dried. Acrylic acid was grafted onto the PVDF membrane surface by dip-coating and ultraviolet (UV) grafting.…”

“…Preparation of a PVDF@CuNi−C Catalytic Membrane. The CuNi−C grafting process is illustrated in Scheme 1 and includes PVDF membrane surface carboxylation, 38 catalyst handling and deposition, 39 and thermal cross-linking. 40,41 PVDF membranes were ultrasonically cleaned with an ethanol−water solution to remove surface impurities and adhered organic contaminants and subsequently dried.…”

Surface modification of a PVDF membrane by co‐grafting hydroxyl and zwitterionic polymers to enhance wettability and antifouling property

“…Also, UV photo-grafting method has the advantages of low cost and easy continuous process compared to one of the conventional coating methods, plasma polymerization process, which usually includes the vacuum process. Moreover, numerous materials can be grafted through UV photo-grafting, [30][31][32][33] with zwitterionic polymer grafting being a typical application. For instance, a polysulfobetaine methacrylate (PSBMA) brush was grafted onto a PVDF membrane to enhance its ultrafiltration performance.…”

Fabricating novel PVDF-g-IBMA copolymer hydrophilic ultrafiltration membrane for treating papermaking wastewater with good antifouling property

“…Ultraviolet (UV)-induced Cu(II)-mediated reversible deactivation radical polymerization (RDRP) is an environmentally friendly synthesis technology which combines UV stimulation and Cu(II)-mediated RDRP (Chuang et al 2014;Hu et al 2018aHu et al , 2018b. UV-induced Cu(II)-mediated RDRP can be used to modify pure PVDF membranes as it enables a more compact combination of hydrophobic and hydrophilic chains to ensure that the hydrophilic chain is fixed on the surface of the PVDF membranes (Cui et al 2019;Zou et al 2020;Li et al 2021). Therefore, the addition of amphiphilic copolymers to PVDF membranes can improve the hydrophilicity and antifouling properties.…”