FTIR studija adsorpcije ugljen-monoksida na izmenjenim zeolitima tipa X, Y i mordenita

In this work Fourier transform infrared (FTIR) study has been applied to study the adsorption of carbon monoxide on transition metal (Mn2+, Co2 Ni2+) ion-exchanged zeolites type Y, X and mordenites. The adsorption of CO at room temperature produces overlapping IR absorption bands in the 2120–2200 cm-1 region. The frequency of the band around 2200 cm-1 is found to be dependent not only on the charge-balancing transition metal cation but also on the framework composition. The frequencies of the band near 1600 cm-1 was found to be dependent on the Si/Al ratio of the investigated zeolites.U ovom radu ispitivana je adsorpcija ugljen-monoksida na izmenjenim zeolitima (Mn2+, Co2+, Ni2+) tipa X, Y i mordenita primenom infracrvene spektroskopije sa Furijeovom analizom (FTIR). Adsorpcijom CO na sobnoj temperaturi nastaju složene trake u spektralnoj oblasti od 2120 do 2200 cm-1.Uočeno je da frekvencija trake na oko 2200 cm-1 zavisi i od katjona prisutnog u strukturi, i od sastava same zeolitske rešetke. Uočeno je takođe da frekvencije traka na oko 1600 cm-1 zavise od strukture, odnosno od Si/Al odnosa ispitivanih zeolita

Termodinamika adsorpcije n-heksana na jonski izmenjenim X zeolitima

In this work, the free energy changes and entropy changes of adsorption of n-hexane on zeolites of the MxNa87-2xX (M=Co,Ni,Zn,Cd) type were determined using their isosteric sorption heats. It was found that the exchange of Na ions in NaX with bivalent cations (Co, Ni, Zn, Cd) significantly alters the adsorption characteristics of NaX zeolite. The free energy changes and entropy changes of n-hexane adsorption were dependent on the surface coverage and on the nature of the charge-balancing cation. The specific influence of the exchanged cations on the free energy changes and entropy changes of sorption of n-hexane originates from the size, location and electronic configuration of the cation.U ovom radu su određene promene slobodne energije i promena entropije adsorpcije n-heksana na zeolitima tipa MxNa87-2xX (M=Co,Ni,Zn,Cd) na osnovu izosternih toplota sorpcije. Pokazano je da izmena Na+ jona u NaX zeolitu dvovalentnim katjonima (Co,Ni,Zn,Cd) značajno menja adsorpcione karakteristike NaX zeolita. Takođe je utvrđeno da promena slobodne energije i promena entropije adsorpcije n-heksana zavisi i od stepena pokrivenosti površine zeolita

Introduction of transition metal cations (Co2+ and Zn2+) into dealuminated NaY zeolite obtained by citric acid treatment

Aluminum ions were extracted from the framework of the faujasite type zeolite NaY (Si/Al=2.4) by citric acid treatment. Dealuminated CoY and ZnY zeolites of high cobalt and zinc content were prepared by replacing sodium ions with Co2+ and Zn2+ in dealuminated Y zeolites, with increased framework Si/Al ratio. Chemical and XRD analyses of zeolites were performed and the FTIR-ATR spectra were recorded. The results of physicochemical analyses are discussed in terms of unit cell (u.c.) composition

Fraktalna analiza površine mezoporoznog aluminijum(III)-oksida sa dodatkom PEG i La(III) dobijenog sol-gel postupkom

Active porous alumina was prepared via a sol-gel method and subjected to thermal treatment in the temperature range 500-1200 °C. The addition of lanthanum effectively inhibited the surface area loss of the aluminas. Fractal analysis from nitrogen adsorption isotherm was used to study the pore surface roughness of alumina samples with different chemical compositions (PEG, PEG and lanthanum) and calcinations conditions in terms of the surface fractal dimension, d. The Mahnke and Mögel (MM) model was used to determine the value of d of La(III)-doped alumina. Following the MM model, the d value of the activated aluminas increased as the calcination temperature increased from 500 to 700 °C but decreased after calcination at 1000, 1100 and 1200 °C. The addition of polyethylene glycol (PEG 5600) to the boehmite sol reduced the surface fractal of the activated alumina due to the heterogeneous distribution of the pores. With increasing La(III) concentration from 0.015 to 0.045 mol La(III)/mol Al(III), the d value of La-modified alumina samples decreased, indicating a smoother surface. The obtained PEG+La-doped boehmite sol can be used as a precursor dispersion for the deposition of mesoporous alumina coatings on stainless steel foil, by the spray pyrolysis method.Aktivni porozni aluminijum-oksid dobijen sol-gel metodom je termički obrađen na povišenim temperaturama u intervalu od 500 do 1200 °C. Ispitivan je uticaj temperature termičke obrade i dodatka polietilen glikola (PEG) i La(III) jona na specifičnu površinu, zapreminu pora i prečnik pora, kao i fraktalnu dimenziju površine aktiviranog aluminijum-oksida. Na osnovu podataka iz adsorpcionoesorpcionih izotermi azota određen je tip pora i izračunate su vrednosti osnovnih parametara teksturalnih svojstava uzoraka. Porast temperature termičke obrade prouzrokovao je smanjenje specifične površine sa 280 na 65 m2 g-1, zapremine pora sa 0,45 na 0,27 cm3 g-1, porast preovlađujućeg prečnika pora od 3 do 6 nm i porast fraktalne dimenzije površine od 2,068 do 2,192. Dobijeni bemitni sol sa dodatkom PEG i La(III) jona može se iskoristiti kao prekursorska disperzija pri sprej-pirolitičkoj metodi sinteze aluminijum oksidnih prevlaka na nosaču od nerđajućeg čelika

Adsorpcija nikotina iz vodenih rastvora na različitim vrstama zeolita

The plant alkaloid, nicotine, is a strongly toxic heterocyclic compound: the lethal dose for an adult human being (40-60 mg) is importantly lower in comparison with the other known poisons such as arsenic or strychni­ne. Cigarettes represent "the most toxic and addictive form of nicotine". Besides the negative effects of nicotine on public health produced by self-administration, recently another potentially very dangerous effect has been recognized: because of its miscibility with water, nicotine can be found in industrial wastewaters, and consequently, in groundwater. Therefore, the problem of nicotine removal from aqueous solutions has became an interesting topic. In this work, the removal of nicotine has been probed by adsorption on solid materials. Adsorption of nicotine on different zeolites (clinoptilolite, ZSM-5 and beta zeolite) and on activated carbon was investigated from aqueous solutions, at 298 K. The obtained results are presented as adsorption isotherms: the amount of adsorbed nicotine as a function of equilibrium concentration. These data were obtained from the residual amount of nicotine in the aqueous phase, by the use of UV spectroscopy. The highest amounts of adsorbed nicotine was found for activated carbon and p zeolite (~ mmol·g-1). The attempt to modify the adsorption properties of ZSM-5 zeolite has been also done: ZSM-5 was modified by ion-exchange with VIII group metal (Cu2+ and Fe3+). In addition, the adsorption of nicotine on ZSM-5 zeolite with different Si/Al ratios has been done. It has been noticed that ion-exchange did not improve the adsorption possibilities, while the adsorption was importantly lower in the case of higher silicon content in ZMS-5 structure. 13C NMR spectra were collected for suspensions formed of solid adsorbent and aqueous solution of nicotine; in this way, the part of nicotine molecule which is most probably connected with the adsorbent was recognized.U ovom radu ispitivana je adsorpcija nikotina iz vodenih rastvora na različitim zeolitima (klinoptilolitu, ZSM-5 i beta zeolitu) kao i na aktivnom uglju visoke specifične površine; na 298K. Dobijeni rezultati prikazani su u formi adsorpcionih izotermi: količina adsorbovanog nikotina u funkciji od ravnotežnih koncentracija nikotina. Ovi podaci dobijeni su iz određivanja količine nikotina preostale u vodenoj fazi, metodom UV spektroskopije. Najveće količine adsorbovanog nikotina utvrđene su na aktivnom uglju i beta zeolitu (~ mmol/g). Iz 13C NMR spektara snimljenih iz suspenzije: čvrsti adsorbent-vodeni rastvor nikotina, utvrđen je atom ugljenika preko koga se molekul nikotina najverovatnije vezuje sa površinama zeolita

Supplementary material for the article: Mihajlović-Lalić, L. E.; Damjanović, L.; Šumar-Ristović, M.; Savić, A.; Sabo, T. J.; Dondur, V.; Grgurić-Šipka, S. Cytotoxic Pt(IV) and Ru(II) Complexes Containing a Biologically Relevant Edda-Type Ligand: A Comparative Study of Their Thermal Properties. Journal of the Serbian Chemical Society 2016, 81 (8), 897–905. https://doi.org/10.2298/JSC160320059M

Supplementary material for: [https://doi.org/10.2298/JSC160320059M]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2325

Syntheses of Pb-ceramic from zeolite precursors: XRPD refinement and SEM/EDS analysis

The Pb-ceramic was syntheses by process of thermally induced phase transformation of Pb-exchange LTA and FAU zeolites. Both frameworks collapse into amorphous intermediate products after heating between 600 and 650 o C. Prolonged heating of the intermediate product over 1100o C results directly in formation of a disorder Pb feldsparLTA [a =8.4171(4) Å, b=13.0532(4) Å, c=7.1722(4) Å, β=115.35(3)°] and Pb-feldsparFAU [a=8.426(4) Å, b=13.0608(4) Å, c=7.1773(4) Å, β=115.36(3)°] phase. The phase conversions in the temperature range investigated were followed by thermal (DTA/TGA), XRPD, and SEM/EDS analyses. The results showed that the Pbceramic could be obtained by process of thermally induced phase transformation of Pbexchange zeolites.I Serbian Ceramic Society Conference : 1CSCS-2011 : program and the book of abstracts; March 17-18, 2011; Belgrad

Removal of Cs Ions from Aqueous Solutions by Using Matrices of Natural Clinoptilolite and its Safe Disposal

The possibility to use natural zeolite - clinoptilolite as a host material for radioactive Cs immobilization has been investigated. Cs-exchanged form of clinoptilolite which was prepared by treatment of clinoptilolite powder with 0.25 M CsCl solution was compacted. Both, powder and powder compact of exchanged clinoptilolite were thermally treated at 1200 C-0. The XRPD analysis showed that Cs was successfully immobilized after heat treatment by formation of stable cesium dodecaoxo-alumopentasilicate in both, powder sample and compact. The newly formed compound showed satisfactory Cs ions retention during leaching test. The sintered compact showed somewhat better resistance to Cs leaching than the thermally treated powder. The compressive strength of sintered compact was close to 200 MPa which is more than enough for easy handling and safe storage

Al, Fe-pillared clays in catalytic decolorization of dye containing water

Al,Fe-pillared clays (PILCs) have shown good performance in catalytic wet peroxide oxidation (CWPO) of organic pollutants in water. They have predominantly been tested in the degradation of phenol. There are seldom reports on their use in the degradation of other organic pollutants such as toluene and dyes. In this work a series of Al,Fe–PILCs with different Fe3+ content was synthesized and characterized. Their catalytic performance was studied in the CWPO of food dye tartrazine used as a model compound. Degree of decolorization of tartrazine containing aqueous solution was monitored in relation to different parameters such as Fe3+ content and temperature

Cytotoxic Pt(IV) and Ru(II) complexes containing a biologically relevant edda-type ligand: A comparative study of their thermal properties

The thermal behaviour of a Pt(IV) and a Ru(II) complex coordinated to dibutyl (S,S)-alpha,alpha'-(1,2-ethanediyldiimino)biscyclohexanepropanoate was investigated using thermogravimetry (TG) and differential scanning calorimetry (DSC). The study included an investigation of the thermal decomposition of these complexes in the temperature range of 30 to 590 degrees C and an evaluation of the activation energy for the first decomposition steps. For both metal complexes, broad DSC peaks indicated complex thermal transformation processes. The two-step decomposition of the Pt(IV) complex started at 175 and ended at about 418 degrees C, leaving elemental platinum as the final residue. On the other hand, the Ru(II) analogue decomposed in three stages. Thermal degradation was evident beginning at 144 degrees C and suggested the decomposition of a coordinated ligand as the dominant process. For this complex, the proposed final residue was RuO2. Kinetic parameters for the first decomposition step were obtained by means of the multi-heating rates method, in this case the Kissinger-Akahira-Sunose (KAS) method. The mean activation energy calculated for 0.2 lt alpha lt 0.8 were 122.0 kJ mol(-1) for the Pt(IV) and 118.9 kJ mol(-1) for the Ru(II) complex and decreased constantly, a characteristic of a multi-step process.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3434