Photocatalytic properties of PVDF membranes modified with g-C3N4 in the process of Rhodamines decomposition

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Kolesnyk, Iryna
Kujawa, Joanna
Bubela, Halyna
Konovalova, Victoria
Burban, Anatoliy
Cyganiuk, Aleksandra
Kujawski, Wojciech
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The PVDF membrane modification was performed utilizing the graphitic carbon nitride (g-C3N4) in order togenerate photocatalytic properties under visible light irradiation. Graphitic carbon nitride was synthesized viaheating of melamine. Commercial PVDF ultrafiltration membranes with cut-offof 150 kDa were activated with acarbonate buffer and g-C3N4was subsequently attached by terminal amino groups. The structural and mor-phological properties of g-C3N4and membrane materials have been characterized using TEM, SEM-EDX, FTIRand EDX analysis. The adsorption of Rhodamine B and Rhodamine 6G on modified membranes and their sub-sequent degradation of dyes were studied. Membranes with immobilized g-C3N4possessed 10 times higheradsorption rate of Rhodamine 6G compared to Rhodamine B. The highest photocatalytic activity of modifiedmembranes has been observed in alkaline media. Using isopropanol,tert-butylhydroquinone, potassium iodineand Cr(VI) as%OH,%O2−,h+andēscavengers, it has been shown that the generated holes have been responsiblefor dyes degradation in acidic media and superoxide radicals in alkaline media, and both of them at neutralconditions. The transport through PVDF-g-C3N4membranes have been characterized by the volumetricflux of320–350 L/(m2·h) during the ultrafiltration of dyes. Rejection of Rhodamine B and Rhodamine 6G was of 96 and94%, respectively. The yield of dyes decomposition was about 80% and 85% for Rhodamine B and Rhodamine6G, correspondingly, within the range of dye concentration from 5 to 50 mg/L. PVDF-g-C3N4membranes werecharacterized with high stability and reusability in process of dyes ultrafiltration in the crossflow mode. The lossof membrane activity after 5 cycles of ultrafiltration (total duration equal to 50 h) was approximately 15%.
Polyvinylidene fluoride membrane, Photocatalytic membrane, Graphitic carbon nitride, Rhodamine B, Rhodamine 6G, Photocatalysis, article
Photocatalytic properties of PVDF membranes modified with g-C3N4 in the process of Rhodamines decomposition / Kolesnyk I., Kujawa J., Bubela H., Konovalova V., Burban A., Cyganiuk A., Kujawski W. // Separation and Purification Technology. - 2020. - Vol. 250. - Article number 117231.