Viktoriia Konovalova

• National University of Kyiv Mohyla Academy

Paper introduces an efficient technique for removing excess Fe(II) ions from water using modified polyvinylidene fluoride membranes. Capability for Fe(II) removal was investigated for three types of PVDF membranes (pristine PVDF, PVDF/Fe3O4 blend, and PVDF/Fe3O4 blend membrane with additional immobilization of Fe3O4 nanoparticles using polymer spac...

This study focuses on creating a method to produce ion-crosslinked alginate-based hydrogel systems that enable immediate drug release. The research investigates the kinetics of releasing a bactericidal drug to facilitate the healing process relief. The technique involves enhancing the immobilization of amphiphilic medicines on calcite microparticle...

In order to provide a method of low-energy membrane emulsification process in food and pharmaceutical industries the water-in-oil (W/O) chitosan emulsions with a narrow droplet size distribution were prepared using 0.1 µm pore size polyethylene terephthalate (PET) track-etched membranes. Droplet size distributions and emulsion stability were studie...

The PVDF membrane modification was performed utilizing the graphitic carbon nitride (g-C3N4) in order to generate photocatalytic properties under visible light irradiation. Graphitic carbon nitride was synthesized via heating of melamine. Commercial PVDF ultrafiltration membranes with cut-off of 150 kDa were activated with a carbonate buffer and g-...

The objective of this study is related to the modification of polyethersulfone membranes with α-amylase incorporated into chitosan-based polymeric micelles in order to reduce the membrane fouling. Amphiphilic chitosan derivatives have been synthesized through grafting of palmitic (PA) and stearic (SA) acids onto low-molecular weight chitosan. CMC v...

The fabrication of novel polyethersulfone membranes with a magnetically active surface nanolayer aiming at the reduction of concentration polarization effect and fouling phenomena is reported. Magnetic nanoparticles (MNPs) with the size smaller than 20 nm were immobilized in boundary layer of the membrane using the polyethylenimine flexible spacer....

A novel method of polyethersulfone membrane modification with α-amylase entrapped in polymeric micelles is proposed to improve the antifouling properties of membranes. The immobilization of α-amylase is performed by its incorporation into micelles based on commercial polymeric surfactants (Tetronic®-701 and Tetronic®-90R4) with their subsequent ads...

In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the im...

Electrolyte hydrogels are perspective materials for applications in electrochemical devices, which work at ambient temperatures. In this work, hydrogel sulpho-modified membranes were formed by radical co-polymerization of sodium styrensulphonate and potassium sulphopropyl acrylate with acrylamide and acrylonitrile. The hydrogel membranes were obtai...

Currently antimicrobial polymer materials are produced by either polymer compounding with inorganic or organic biocides or by coating polymer surfaces with biocidal molecules including chemical binding. The general problems with the additive approach are poor compatibility between many biocides and majority polymers, decreasing in mechanical and ot...

To render the surface of ultrafiltration membranes biocidal, cellulose membranes were modified with chitosan, a naturally occurring polycationic biocide. Through the use of chitosans of different molecular weights and membranes with different pore sizes, the alteration of the morphological structure of tethered chitosan layers was achieved. The imp...

A robust processing of polymers into antimicrobial materials is introduced using polymer/clay nanotechnology. Antimicrobial activity of commercially available organoclays modified with cationic surfactants has been screened in tests against gram-negative Escherichiacoli and gram-positive Staphylococcusaureus bacteria. Despite the leaching biocidal...

Sequential reduction of chromate and nitrate, two competitive electron acceptors, has been demonstrated for strains of Pseudomonas genus for both planktonic cells and cells immobilised in agar layers on the surface of synthetic membrane. Denitrification occurs practically after chromate depletion. This order of reduction process is consistent with...

A study of the reduction of chromium (VI) and nitrate or manganese (IV) ions present in the cultivation medium of denitrifying bacteria of the genus Pseudomonas showed that Cr(VI) ions are reduced first. The rate of Cr(VI) reduction was found to be independent of the presence of Mn(IV) or nitrate ions in the medium.

Chromate reduction was studied in a membrane bioreactor under action of Pseudomonas bacteria immobilized in agar–agar films on the surface of synthetic membrane. Immobilized cells are protected from the excessive toxic action at high chromate concentration that improves cell activity compared with free cells. Almost complete chromate reduction was...

Non-nitrate-reducing collection bacteria from the genus Pseudomonas were found to be able to use hexavalent chromium as a terminal electron acceptor. The reduction of Cr(VI) was accompanied by an increase in the cell biomass. At the Cr(VI) concentrations in the medium lower than 15 mg/l, the non-nitrate-reducing pseudomonads reduced Cr(VI) less eff...

Non-nitrate-reducing collection bacteria from the genus Pseudomonas were found to be able to use hexavalent chromium as a terminal electron acceptor. The reduction of Cr(VI) was accompanied by an increase in the cell biomass. At Cr(VI) concentrations in the medium lower than 15 mg/l, the non-nitrate-reducing pseudomonads reduced Cr(VI) less efficie...

A possibility to prepare the biofunctional membranes showing the biocatalytic properties and use those in post-treatment of wastewater containing synthetic dyes have been established. Selected Pseudomonas mendocina and Bacillus subtilis cultures were used as biocatalysts for dye destruction. It has been established that cells in spore form are able...