Науково-дослідний Центр мембранних досліджень

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https://ekmair.ukma.edu.ua/handle/123456789/15612
Науково-дослідний Центр мембранних досліджень (ЦМД) - є науковим підрозділом НаУКМА, який тісно співпрацює з кафедрою хімії факультету природничих наук. Науково педагогічні співробітники кафедри хімії та ЦМД мають значний досвід роботи в галузях полімерної хімії, хімії композиційних та функціональних матеріалів, полімерних мембран, мембранних технологій та біотехнологій.

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    Fe2+ Removal from Water Using PVDF Membranes, Modified with Magnetite Nanoparticles, by Polyelectrolyte Enhanced Ultrafiltration
    (2018) Konovalova, Victoria; Kolesnyk, Iryna; Ivanenko, Olena; Burban, Anatoliy
    The aim of this study was to show results of Fe2+ removal from water by polyelectrolyte enhanced ultrafiltration on polyvinylidene fluoride membranes modified with magnetite nanoparticles. Magnetite nanoparticles were synthesized by the co-precipitation method and stabilized with sodium polyacrylate. At first stage, the surface of PVDF membranes was modified by grafting of polyethylenimine. At the second stage the polyelectrolyte, grafted to the membrane surface, was used as a linker for magnetite nanoparticles immobilization. The modification of membranes was confirmed by IR spectroscopy, scanning electron microscopy and electro kinetic analysis. The dependence of zeta-potential on pH for PVDF membrane modified with PEI has confirmed the modification of the membrane surface as zeta-potential increases with pH decrease. SEM has shown that the surface of modified membrane is densely covered with nanoparticles, which form clusters. The dependence of the volumetric flux on the applied pressure at various concentrations of the carboxymethylcellulose (CMC) has been studied. Polyelectrolyte enhanced ultrafiltration with CMC has been used for iron(II) removal at initial Fe2+ concentration of 20 mg/L. The concentrations of iron(II) in permeate using an unmodified membrane has ranged from 0.6 to 1.0 mg/L, whereas for the modified membrane it has been 0.02÷0.08 mg/L.
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    Photocatalytic properties of PVDF membranes modified with g-C3N4 in the process of Rhodamines decomposition
    (2021) Kolesnyk, Iryna; Kujawa, Joanna; Bubela, Halyna; Konovalova, Victoria; Burban, Anatoliy; Cyganiuk, Aleksandra; Kujawski, Wojciech
    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%.