Publications by authors named "Maria Kapnisti"

The removal of radioactive contaminants from aquifers is a matter of great concern. In this paper, coated copper-based nanoparticles (Cu-based NPs) were investigated as sorbent materials to remove uranium and thorium from low-level wastes, and especially from water, considering the influences of temperature, time, concentration, and pH. Cu-based NPs were derived through a hydrothermal synthesis from copper nitrate degradation in the presence of the bifunctional with COOH-terminated PEG, TEG as well as PEG 8000.

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The Cs- and Ba-sorption, onto bentonite from Kimolos island (Cyclades, Greece) was investigated in aqueous solutions in the presence of Na, Ca and humic acid. Batch experiments were performed using as tracers Cs and Ba and γ-ray spectroscopy. The sorption significantly depended on initial concentration, ionic strength and temperature of the solutions.

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Intending to expand the thermo-physical properties of bio-based polymers, furan-based thermoplastic polyesters were synthesized following the melt polycondensation method. The resulting polymers, namely, poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), poly(butylene 2,5-furandicarboxylate) (PBF) and poly(1,4-cyclohexanedimethylene 2,5-furandicarboxylate) (PCHDMF) are used in blends together with various polymers of industrial importance, including poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), poly(L-lactic acid) (PLA) and polycarbonate (PC). The blends are studied concerning their miscibility, crystallization and solid-state characteristics by using wide-angle X-ray diffractometry (WAXD), differential scanning calorimetry (DSC) and polarized light microscopy (PLM).

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Poly(butylene 2,5-furandicarboxylate) (PBF) constitutes a new engineering polyester produced from renewable resources, as it is synthesized from 2,5-furandicarboxylic acid (2,5-FDCA) and 1,4-butanediol (1,4-BD), both formed from sugars coming from biomass. In this research, initially high-molecular-weight PBF was synthesized by applying the melt polycondensation method and using the dimethylester of FDCA as the monomer. Furthermore, five different series of PBF blends were prepared, namely poly(l-lactic acid)-poly(butylene 2,5-furandicarboxylate) (PLA-PBF), poly(ethylene terephthalate)-poly(butylene 2,5-furandicarboxylate) (PET-PBF), poly(propylene terephthalate)-poly(butylene 2,5-furandicarboxylate) (PPT-PBF), poly(butylene 2,6-naphthalenedicarboxylate)-poly(butylene 2,5-furandicarboxylate) (PBN-PBF), and polycarbonate-poly(butylene 2,5-furandicarboxylate) (PC-PBF), by dissolving the polyesters in a trifluoroacetic acid/chloroform mixture (1/4 /) followed by coprecipitation as a result of adding the solutions into excess of cold methanol.

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New materials were synthesized for application in sorption of radionuclides from aqueous solutions. The elaboration was performed by conversion of power plant ash using the hydrothermal method under optimum experimental conditions. Sodalite, Na-Y, and analcime were formed from ash precursor during the treatment, exhibiting thermal stability as revealed by the characterization by X-ray diffraction (XRD) and thermogravimetric differential thermal analysis (TG-DTA).

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