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The review of some novel biomarkers in sedimentary organic matter
No full textA series of novel C33-C35 hexacyclic benzohopanes have been identified in coals and crude oils
of different ages from all over the world [1]. They differ from regular benzohopanes by the presence
of methyl group in position C-31. These compounds are more abundant in coals and terrestrial oils.
The investigation also showed that mature samples have distributions of benzohopanes distinct from
immature ones, which are characterised by a greater number of benzohopane isomers. Although exact
structures of the additional isomers were not determined, it seems they were formed by an
isomerisation of alkyl groups attached to the aromatic ring.
Two novel monoaromatic hydrocarbons (MW = 270; basic fragment ions m/z 255 and 146)
were identified in coals, mudstones and crude oils. Their structures were determined as cis- and transicetexa-
8,11,13-trienes (or dehydroicetexanes) using NMR spectroscopy. Dehydroicetexanes are
potential biomarkers of Cupressaceae (cypress conifers).
Benzo[b]naphtho[d]furans (BNFs) have been identified in oils, condensates, source-rocks,
coals and coaly shales, being more abundant in the latter. We detected BNFs (m/z 218) in relatively
high amounts in the aromatic fractions of pyrolysates of brown coals which attained the maturity
corresponding to vitrinite reflectance of 1.80 %Rr [2]. This result suggests that BNFs can be attractive
for investigations of mature fluids that originate from gas/condensate prone sources, rich in type III
kerogen, which are usually depleted in biomarkers. Recently, it was observed that [2,1]/[1,2]BNF
ratio can be used to describe lithofacies [3]. This ratio is much lower in sediments from fluvial-deltaic
systems than in clay-depleted sediments from marine environments.
1-Chloro-n-alkanes (m/z 91) have been identified in saltmarsh vegetation, recent sediments
from estuarine setting and freshwater lake sediments [4]. Despite their absence in the investigated
crude oils, we identified a series of 1-chloro-n-alkanes in pyrolysates of the corresponding
asphaltenes, obtained at 250 oC. This result indicates very good preservation of biomarkers occluded
inside asphaltenes and announces a possible application of 1-chloro-n-alkanes in correlation studies
Adsorption of chromates, arsenates and selenates on raw vulcanic rock found on Etna
No full textFinding the raw material which can be used as adsorbent of heavy metals from water solution without any modification would be beneficial for solving the capital issue of water pollution. Heavy metal water pollution is a problem of almost every single country, so in the near future huge amounts of adsorbents would be needed to reduce the level of water pollutants. Considering this fact it is necessary to find available, abundant and cheap raw material which can be utilized as adsorbent as is or with minor processing. A plenty of mineral raw material fulfil all requirements of the potential cheap adsorbent. Aim of this paper is to determine potential of volcanic rock found in Etna valley as an adsorbent of heavy metals in anionic form (chromates, arsenates and selenates). Characterization of the volcanic rock was done with chetnical methods (AAS, AES, gravimetric analysis, XRF) and physicochetnical methods (XRD, FTIR, SEM). Also maximal adsorption capacity was determined. All the results of adsorption capacity were satisfying considering the mineral composition, granulation and porosity
Mineralogy and crystallographic properties of HEU-type zeolitic tuff from the Novaković deposit, Bosnia and Herzegovina
No full textU radu su predstavljeni rezultati mineraloške i strukturne analize zeolitskog tufa lokaliteta Novaković, u Bosni i Hercegovini. Tuf je beličaste boje, osnovni mineralni sastav je mineral iz serije hejlandita – Ca-klinoptilolit. Prateća komponenta je amorfna faza, vulkansko staklo i amorfni SiO2. Ispitivanjem termičke stabilnosti, utvrđeno je da je struktura zeolita stabilna do 600 oC. Određivana je i struktura Ca-klinoptilolita u zeolitskom tufu. Struktura je utačnjavana u prostornoj grupi C2/m, sa neuređenom raspodelom Al i Si u tetraedarskoj mreži. Za ispitivanje su korišćene metode rendgenske difrakcije praha na polikristalnom uzorku (XRD, X-Ray powder diffraction analysis), skenirajuće elektronske mikroskopije i energodisperzivne spektroskopije x-zracima (SEM/EDS, scanning electron microscopy and energy dispersive spectroscopy analysis) i diferencijalno termička i diferencijalno termogra-vimetrijska analiza (DTA/DTG, differential thermal and thermogravimetric analysis).This paper presents mineralogical and crystallographic characterization of the zeolitic tuff from the Novakovic deposit, Republic of Bosnia and Herzegovina. The zeolitic tuff is of a whitish color composed of Ca-clinoptilolite and an amorphous phase (volcanic glass and amorphous SiO2). The zeolitic tuff was analyzed by X-ray diffraction of the polycrystalline sample (XRPD), scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), and differential thermal and thermo- gravimetric (DTA/DTG) methods. According to the results obtained, it can be concluded that the studied zeolitic tuff is composed of Heu-type minerals. Based on the chemical analysis, thermal treatment and XRPD analysis it was determined that this is a mineral Ca-clinoptilolite. Thermal analysis in the temperature range from 300 up to 700ºC showed that the examined zeolite minerals from the Novaković deposit are stable up to the temperature of 600ºC. The crystal structure of Ca-clinoptilolite has been refined in the centrosymmetric space group C2/m (S.G. 12) with disordered distribution of Al and Si in the tetrahedral framework. The unit-cell parameters are as follows: a = 17.662 Å, b = 17.874 Å, c = 7.402 Å, β = 116.32º and V = 2122.73 Å3. The basic structural motif is represented by four channels. Three channels are composed of eight-membered rings, and one of ten-membered rings. The ten-membered (channel A) and one eight-membered channel (B) are parallel to the crystallographic axis c, and the other eight-membered channel is parallel to the a-axis. Ca-clinoptilolite comprises approximately 90 % of the studied zeolite tuff while the rest 10 % is the amorphous phase. The overall cation exchange capacity (CEC) amounts to 187 mmolM+/100g, and calcium represents the most abundant cation in the studied sample. The atomic ratios of Si/Al, Na+/(Na++K+), and Ca2+/(Ca2++Mg2+) are as follows: 4.36, 0.14, and 0.55, respectively. The zeolite tuff is both thermally and structurally stable and has applications in various areas of industry and agriculture
Elektroforetski taložene biokeramičke kompozitne prevlake sa gentamicinom za biomedicinsku namenu u formi koštanih implantata
No full textSposobnost osteointegracije i izvanredna biokompatibilnost hidroksiapatita (HAP) u
kombinaciji sa dobrim mehaničkim i antimikrobnim svojstvima hitozana (CS) uz dodatak
antibiotika gentamicina (Gent) omogućava dobijanje biokompatibilnih prevlaka sa
poboljšanom biološkom funkcijom. U cilju povećanja biokompatibilnosti i bioaktivnosti
titanskih (Ti) implantata, izvršena je modifikacija površine Ti nanošenjem biokeramičke
HAP/CS/Gent prevlake postupkom elektroforetskog taloženja (EPD). Taloženje je izvedeno
u jednom stupnju, iz trokomponentne vodene suspenzije pri konstantnom naponu.
Karakterizacija dobijenih prevlaka je izvršena primenom infracrvene spektroskopije sa
Furijeovom transformacijom (FT-IR) i skenirajuće elektronske mikroskopije (FE-SEM).
Citotoksičnost dobijenih prevlaka je ispitana MTT testom, a primenom testa u suspenziji
verifikovana je antibakterijska aktivnost. Dobijeni rezultati su potvrdili formiranje nove
kompozitne prevlake HAP/CS/Gent sa velikim potencijalom za upotrebu u biomedicini.The ability of osseointegration and excellent biocompatibility of hydroxyapatite (HAP)
combined with good mechanical and antimicrobial properties of chitosan (CS) with the
addition of antibiotic gentamicin (Gent), enabled the production of biocompatible coatings
with improved biological function. In order to increase the biocompatibility and bioactivity
of titanium (Ti) implants, Ti surface was modified by applying the bioceramic HAP/CS/Gent
coating using electrophoretic deposition process (EPD). Deposition was carried out in one
step from a three-component aqueous suspension (HAP/CS/Gent) at constant voltage. The
obtained coatings were characterized by Fourier transform infrared spectroscopy (FT-IR),
and field emission scanning electron microscopy (FE-SEM). The cytotoxicity of the obtained
coatings was evaulated by MTT assay, and the antibacterial activity was verified using test
in suspension. Results obtained confirmed the formation of a new HAP/CS/Gent composite
coating with future prospect for biomedical use
Ag-doped fluorapatite nanomaterials obtained by neutralization method
No full textSrebrom dopirani fluorapatiti (AgFAP) su sintetisani postupkom neutralizacije
(reakcija Ag2O rastvarenog u HF i H3PO4 sa suspenzijom Ca(OH)2). [1] Sintetisani
uzorci AgFAP imali su procentnu zastupljenost jona srebra ([Ag/(Ag + Ca)]·100%) od
0.001, 0.01 i 1%. Rendgenska difraktometrijska (XRD) analiza uzoraka FAP i AgFAP
pokazala je da su položaji difrakcionih pikova slični i da su u skladu sa ASTM podacima za fluorapatite (Slika 1). FAP kao materijal ima kristalnu rešetku sa heksagonalnom P63/m prostornom grupom, sa dva strukturno različita položaja Ca2+ jona (Ca1 (4f) i Ca2 (6h) položaji). FTIR and SEM analize pokazale su da su čestice AgFAP uzoraka homogene i nano-veličine. Fluorescencija AgFAP uzoraka je pomerena ka zelenom regionu, u odnosu na fluorescenciju FAP nanočestica (u ljubičastom regionu vidljivog dela spektra). MCR ALS analize su pokazale formiranje dva maksimuma u AgFAP fluorescentnom spektru (na 420 i 520 nm), kao posledica dopiranja Ag+ jona u Ca1 (4f) položaj FAP rešetke (Slika 1). Rezultati DFT proračuna su pokazali da je Ag+ jon jače vezan u Ca1 položaju (-1352,6 kcal/mol) nego u Ca2 položaju (-1249.0 kcal/mol). Ispitivanja antibakterijskih aktivnosti su pokazale da svi uzorci AgFAP imaju biocidni efekat na patogene, [1] dok samo AgFAP3 uzorak (1% Ag+) može poslužiti kao nanomaterijala za zaštitu od zračenja, kao i za pripremu fotoluminiscentnih dozimetara, jer ovaj materijal apsorbuje fotone u celoj oblasti UV zračenja. Rezultati ove studije ukazuju da su srebrom dopirani fluorapatitni
nanomaterijali pogodni za različite biomedicinske primene, kao antibakterijski
biomaterijali u ortopediji, stomatologiji i u prečišćavanje otpadnih voda.Silver doped fluorapatite (AgFAP) nanopowders were synthesised by
neutralization method (reaction of dissolving Ag2O in solution of HF and H3PO4 with suspension of Ca(OH)2). [1] AgFAP samples were synthesized with atomic ratios of [Ag/(Ag + Ca)]·100% of 0.001, 0.01 and 1%. The XRD patterns of FAP and Ag+-doped FAP samples (Figure 1) are similar, with the positions of X-ray diffraction peaks in accordance with ASTM data for fluorapatite. FAP as material has a crystal lattice with a hexagonal symmetry space group P63/m, with two structurally different positions of Ca2+ ion (Ca1 (4f) and Ca2 (6h) sites). FTIR and SEM analysis showed that the particles of AgFAP samples are nano-sized and homogenous. Fluorescence of AgFAP is red shifted to the green region compared to fluorescence of FAP nanoparticles (in the violet region of visible part of the spectrum). MCR-ALS analyses showed the formation of two maxima in AgFAP fluorescence spectra (at 420 and 520 nm), as a consequence of Ag+ ions doping at Ca1 (4f) site in the FAP lattice (Figure 1). The results of DFT calculations showed that an Ag+ ion is stronger bonded to Ca1 site (-1352.6 kcal/mol) than to Ca2 site (-1249.0 kcal/mol). Antibacterial studies have shown that all studied AgFAP samples exhibit biocidal effect against pathogens, [1] while only AgFAP3 (1% of Ag+) nanopowder might be used as the radiation protective nanomaterial, as well as for preparation of photoluminescence dosimeters, because this material absorbs photons over all part of the UV radiation spectrum. The result of this study indicates that Ag-doped fluorapatite nanomaterials are promising for different biomedical applications, as antibacterial biomaterials in orthopedics, dentistry and in the purification of waste water
Compound spinel as a masking pigment obtained by mechanochemical treatment
No full textMechanochemical and thermal treatment of metal oxides (Chromium, Cobalt, Zinc,
Titanium, Magnesium, and Aluminum oxides) results in the formation of compound spinel with
a formula Co0.51Zn0.29Mg0.41Cr1.24Al0.24Ti0.31O4 - used as masking pigment. Such treatment of
metallic oxides initiates a complex series of transformation using mechanical energy disturbing
the arrangement of the crystal and molecular structure, as chemical and thermodynamic balance.
With optical and scanning electron microscopy with EDX analysis. X-ray and chemical analysis
of the resulting spinel - the quality, structure, grain size and color of the obtained spinel were
determined. Also, the reaction surfaces, the resulting phase transformations, and the degree of
formed dislocations and defects in the crystal lattice of the obtained spinel were determined. By
the obtained results, the optimal conditions of the mechanochemical process have been designed,
which involve the design the vibration mill (geometry, ceramic balls, and other), grinding time,
the temperature in the mill, and rpm of the mill
Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering
No full textThe influence of the sintering method on the mineral phase transformations and development of the crystalline microstructure of steatite ceramics was investigated. The steatite samples were fabricated from talc and bentonite as low-cost raw materials. Feldspar and barium carbonate, as fluxing agents, were altered in the steatite composition. Dilatometric analysis was applied in the monitoring of the dimensional changes and thereby densification of steatite during the traditional sintering (TS) procedure up to 1200 degrees C. Spark plasma sintering (SPS) method was used under the following sintering conditions: 100 degrees C/min heating rate, uniaxial pressure of 50 MPa; sintering temperature 800 degrees C/1 min or 1000 degrees C/2 min. Crystallinity changes and mineral phase transition during sintering were observed by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy equipped with the EDS mapping. It was found that SPS sintering facilitated all microstructural changes during high temperature treatment and shifted them to lower temperatures. SPS treatment conducted at 1000 degrees C resulted in maximum densification of the steatite powder compacts and the formation stabilized protoenstatite structure
An artificial neural network approach for the estimation of the primary production of energy from municipal solid waste and its application to the Balkan countries
No full textAlthough the use of municipal solid waste to generate energy can decrease dependency on fossil fuels and consequently reduces greenhouse gases emissions and areas that waste occupies, in many countries municipal solid waste is not recognized as a valuable resource and possible alternative fuel. The aim of this study is to develop a model for the prediction of primary energy production from municipal solid waste in the European countries and then to apply it to the Balkan countries in order to assess their potentials in that field. For this purpose, general regression neural network architecture was applied, and correlation and sensitivity analyses were used for optimisation of the model. The data for 16 countries from the European Union and Norway for the period 2006-2015 was used for the development of the model. The model with the best performance (coefficient of determination R-2 = 0.995 and the mean absolute percentage error MAPE = 7.757%) was applied to the data for the Balkan countries from 2006 to 2015. The obtained results indicate that there is a significant potential for utilization of municipal solid waste for energy production, which should lead to substantial savings of fossil fuels, primarily lignite which is the most common fossil fuel in the Balkans
Application of multi-criteria decision-making methods for managing quality and beneficiation of pelletized fly ash
No full textThe aim of this work is to analyze the impact and the potentials of multiple criteria decision-making methods (MCDM) especially focusing on its application in the field of sustainable solutions to waste problems. To demonstrate the applicability of MCDM methods in the field of mineral processing, the fly ash pellets selection problem was considered. Studies reported in this paper used three selected size fractions of pelletized fly ash, from power plant Nikola Tesla —B, Obrenovac, obtained at different amounts of the binder. Physical-mechanical properties of pellets samples were tested, afterwards the complex methods of multi-criteria decision making was presented, with the objective to determine adequate pellets for producing lightweight concrete. The criteria weighting was performed firstly, by AHP method, afterwards a decision model was applied, by using TOPSIS method. Fly ash pellets were ranked and the results obtained that the best pellet quality was archived for mean diameter (D9) of 11.21 mm and 8.36 mm, with compressive strength
of 6 MPa
Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia)
No full textThe Turija oil field, being an important oil field in Serbia, is located in the Banat Depression of
the southeastern part of the Pannonian Basin. Oil samples from the Turija oil field were investigated
in order to estimate origin, depositional environment, thermal maturity and age of the corresponding
source rocks. For that purpose, a comprehensive analysis of biomarkers and aromatic compounds was
performed.
n-Alkanes are predominant compounds in the total ion chromatograms of saturated fractions of
all samples, showing that Turija oils are not biodegraded. The distributions of n-alkanes, which are
characterised by equivalent abundances of long- and short-chain homologues and maximums at C17,
C21 and C27, suggest a mixed aquatic-terrestrial origin. The uniform distributions of regular C27-C29
5α(H)14α(H)17α(H) 20(R) steranes support the previous assumption. The presence of oleanane in all
samples is indicative for a contribution of angiosperm plants to the precursor organic matter (OM).
Furthermore, the presence of this biomarker implies the Upper Cretaceous or younger age of the
corresponding source rocks. Isoreniratane and its derivatives have been identified in all samples.
Although isorenieratane can originate from β-carotene, which is widespread in algae, bacteria and
terrestrial plants, the presence of other catagenetic products of isorenieratene (mass fragmentogram
m/z 133 of the aromatic fraction) unambiguously confirms a contribution of green sulphur bacteria
Chlorobiaceae to the precursor organic material [1].
The pristane to phytane (Pr/Ph) ratio ranges from 0.64 to 1.17, indicating reducing to dysoxic
conditions during the deposition of precursor OM. The presence of the above mentioned
isorenieratane derivatives implies the photic zone of anoxia. The stratification of water column is also
supported by the presence of gammacerane and values of gammacerane index, GI = gammacerane x
10/(gammacerane + C30 17α(H)21β(H)-hopane) > 1 in almost all the samples. Alkylated 2-methyl-2-
(4,8,12-trimethyltridecyl) chromans (MTTCs) were detected in all studied oils. A predominance of
5,7,8-trimethyl-MTTC over 5,8-dimethyl-MTTC, 7,8-dimethyl-MTTC and 8-methyl-MTTC,
associated with the values of MTTC ratio (MTTC = 5,7,8-trimethyl-MTTC/ΣMTTCs) in 0.44 to 0.65
range, indicates deposition of OM in a brackish environment [2].
The maturity of Turija oils was determined using typical sterane and hopane isomerisation
maturity parameters and methyldibenzothiophene ratio, MDBTR = 4-MDBT/1-MDBT [3]. The
obtained results indicate that Turija oils were generated in an early stage of oil window