Vladimir Dodevski

Analysis of the Interaction of Pulsed Laser with Nanoporous Activated Carbon Cloth

Interaction of pulsed transversely excited atmospheric (TEA) CO2-laser radiation at 10.6 μm with nanoporous activated carbon cloth was investigated. Activated carbon cloth of different adsorption characteristics was used. Activated carbon cloth modifications were initiated by laser pulse intensities from 0.5 to 28 MW/cm2, depending on the cloth adsorption characteristics. CO2 laser radiation was effectively absorbed by the used activated carbon cloth and largely converted into thermal energy. The type of modification depended on laser power density, number of pulses, but mostly on material characteristics such as specific surface area. The higher the surface area of activated carbon cloth, the higher the damage threshold.

Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O () as Solid Solutions

The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095 () with the fluorite type crystal structure of CeO2 were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4

Optimization of Active Carbonaceous Material Obtained by Low Hydrothermal Carbonization of Plane Tree Seed with H3PO4

Activated carbons (ACs) were successfully prepared using plane tree seed (PTS) as a cheap and renewable raw material. The plane tree seeds were firstly treated combining magnetic (MM) and ultrasonic mixing (USM) during 0.5, 1 and 3 h in 1 M, 3 M and 6 M of H3PO4 solutions, and then activated at 260 °C during 20 h (low temperature hydrothermal carbonization–low HTC) in above mentioned solutions of the same molarity. The influence of combined mixing and activation processes on physical, structural and morphological properties, and their optimization was studied by X-ray powder diffraction (XRPD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis.

ADSORPCIJA METILENSKOG PLAVOG NA AKTIVNOM UGLJENIKU DOBIJENOM OD PLODA PLATANA

Plod platana je koriscen za dobijanje praskastog aktivnog uglja. Kao aktivirajuce sredstvo u pripremi je upotrebljena koncentrovana fosforna kiselina. Izvrsena je ravnotežna adsorpcija katjonske boje metilen plavo na sintetizovanom materijalu. Dobijeni rezultati su fitovani sa tri ravnotežna adsorpciona modela. Eksperimentalni rezultati su analizirani od strane Langmuir izoterme, Freundlich izoterme i Temkin izoterme. Najbolje slaganje eksperimentalnih rezultata sa teorijskim modelima je dobijeno u slucaju Langmuir-ovog ravnotežnog modela. Prema Langmuirovom modelu, postignut je najbolji adsorpcioni kapacitet boje na adsorbentu koji iznosi 354,60 mg g-1 kada je aktivan ugalj tretiran sa NaOH.