TY  - CONF
AU  - Vuković, N.
AU  - Nytoft, H.P.
AU  - Stojanović, Ksenija A.
PY  - 2019
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5172
AB  - The aim of this study is to check which of four performed oil asphaltene treatments shows the best similarity in distributions of biomarkers and aromatic hydrocarbons and in the values of corresponding parameters with those obtained for maltenes. The obtained results imply the lack of a unique method which can result in good fitting of all biomarker and alkylaromatic ratios in oil asphaltene treatment products and corresponding maltenes. Among the performed asphaltene treatments two methods deserve attention: oxidation by NaIO4/NaH2PO4 and pyrolysis at 400 oC.
PB  - European Association of Geoscientists & Engineers
C3  - Conference Proceedings, 29th International Meeting on Organic Geochemistry
T1  - The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils
VL  - 2019
DO  - 10.3997/2214-4609.201902944
ER  - 

@conference{
author = "Vuković, N. and Nytoft, H.P. and Stojanović, Ksenija A.",
year = "2019",
abstract = "The aim of this study is to check which of four performed oil asphaltene treatments shows the best similarity in distributions of biomarkers and aromatic hydrocarbons and in the values of corresponding parameters with those obtained for maltenes. The obtained results imply the lack of a unique method which can result in good fitting of all biomarker and alkylaromatic ratios in oil asphaltene treatment products and corresponding maltenes. Among the performed asphaltene treatments two methods deserve attention: oxidation by NaIO4/NaH2PO4 and pyrolysis at 400 oC.",
publisher = "European Association of Geoscientists & Engineers",
journal = "Conference Proceedings, 29th International Meeting on Organic Geochemistry",
title = "The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils",
volume = "2019",
doi = "10.3997/2214-4609.201902944"
}

Vuković, N., Nytoft, H.P.,& Stojanović, K. A.. (2019). The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils. in Conference Proceedings, 29th International Meeting on Organic Geochemistry
European Association of Geoscientists & Engineers., 2019.
https://doi.org/10.3997/2214-4609.201902944

Vuković N, Nytoft H, Stojanović KA. The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils. in Conference Proceedings, 29th International Meeting on Organic Geochemistry. 2019;2019.
doi:10.3997/2214-4609.201902944 .

Vuković, N., Nytoft, H.P., Stojanović, Ksenija A., "The applicability of asphaltene treatment (mild oxidation and pyrolysis) in the investigation of crude oils" in Conference Proceedings, 29th International Meeting on Organic Geochemistry, 2019 (2019),
https://doi.org/10.3997/2214-4609.201902944 . .

TY  - CONF
AU  - Stevanović, J.
AU  - Vuković, N.
AU  - Stojanović, Ksenija A.
PY  - 2019
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5171
AB  - Oils from recently drilled wells in the Turija-Sever oil field were investigated in order to understand their genetic relationships, and to define the depositional environment, thermal maturity and geologic age of the corresponding source rocks, which are still unknown. Oils from the Turija-Sever oil field are generally similar and probably belong to the same genetic type. They originate from source rocks deposited in reducing to dysoxic redox conditions, with organic matter (OM) originating from mixed marine/terrestrial sources. Slight differences among oils are reflected through certain lower contribution of algal OM to oils from the northern part of the field and/or its faster degradation under dysoxic conditions. Oils were generated from source rocks in an early stage of oil window, corresponding to vitrinite reflectance between 0.60 and 0.65 %. Source rocks are of Tertiary age. Estimated source rocks depth interval and temperature interval of oil generation correspond to 2300 m – 2500 m and 124 °C – 138 °C, respectively.
PB  - European Association of Geoscientists & Engineers
C3  - Conference Proceedings, 29th International Meeting on Organic Geochemistry
T1  - Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia)
VL  - 2019
DO  - 10.3997/2214-4609.201902803
ER  - 

@conference{
author = "Stevanović, J. and Vuković, N. and Stojanović, Ksenija A.",
year = "2019",
abstract = "Oils from recently drilled wells in the Turija-Sever oil field were investigated in order to understand their genetic relationships, and to define the depositional environment, thermal maturity and geologic age of the corresponding source rocks, which are still unknown. Oils from the Turija-Sever oil field are generally similar and probably belong to the same genetic type. They originate from source rocks deposited in reducing to dysoxic redox conditions, with organic matter (OM) originating from mixed marine/terrestrial sources. Slight differences among oils are reflected through certain lower contribution of algal OM to oils from the northern part of the field and/or its faster degradation under dysoxic conditions. Oils were generated from source rocks in an early stage of oil window, corresponding to vitrinite reflectance between 0.60 and 0.65 %. Source rocks are of Tertiary age. Estimated source rocks depth interval and temperature interval of oil generation correspond to 2300 m – 2500 m and 124 °C – 138 °C, respectively.",
publisher = "European Association of Geoscientists & Engineers",
journal = "Conference Proceedings, 29th International Meeting on Organic Geochemistry",
title = "Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia)",
volume = "2019",
doi = "10.3997/2214-4609.201902803"
}

Stevanović, J., Vuković, N.,& Stojanović, K. A.. (2019). Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia). in Conference Proceedings, 29th International Meeting on Organic Geochemistry
European Association of Geoscientists & Engineers., 2019.
https://doi.org/10.3997/2214-4609.201902803

Stevanović J, Vuković N, Stojanović KA. Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia). in Conference Proceedings, 29th International Meeting on Organic Geochemistry. 2019;2019.
doi:10.3997/2214-4609.201902803 .

Stevanović, J., Vuković, N., Stojanović, Ksenija A., "Origin of oils and source rocks characterization of the Turija-Sever oil field (SE Pannonian Basin, Serbia)" in Conference Proceedings, 29th International Meeting on Organic Geochemistry, 2019 (2019),
https://doi.org/10.3997/2214-4609.201902803 . .

TY  - CONF
AU  - Stojanović, Ksenija A.
AU  - Nytoft, H.P.
AU  - Kildahl-Andersen, G.
AU  - Vuković, N.
PY  - 2018
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5187
AB  - A 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.
PB  - IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Tomsk
C3  - 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings
T1  - The review of some novel biomarkers in sedimentary organic matter
SP  - 673
DO  - 10.17223/9785946217408/422
ER  - 

@conference{
author = "Stojanović, Ksenija A. and Nytoft, H.P. and Kildahl-Andersen, G. and Vuković, N.",
year = "2018",
abstract = "A 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.",
publisher = "IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Tomsk",
journal = "10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings",
title = "The review of some novel biomarkers in sedimentary organic matter",
pages = "673",
doi = "10.17223/9785946217408/422"
}

Stojanović, K. A., Nytoft, H.P., Kildahl-Andersen, G.,& Vuković, N.. (2018). The review of some novel biomarkers in sedimentary organic matter. in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings
IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Tomsk., 673.
https://doi.org/10.17223/9785946217408/422

Stojanović KA, Nytoft H, Kildahl-Andersen G, Vuković N. The review of some novel biomarkers in sedimentary organic matter. in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings. 2018;:673.
doi:10.17223/9785946217408/422 .

Stojanović, Ksenija A., Nytoft, H.P., Kildahl-Andersen, G., Vuković, N., "The review of some novel biomarkers in sedimentary organic matter" in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings (2018):673,
https://doi.org/10.17223/9785946217408/422 . .

TY  - CONF
AU  - Stevanović, J.
AU  - Teslić, S.
AU  - Kharchenko, I.P.
AU  - Vuković, N.
AU  - Stojanović, Ksenija A.
PY  - 2018
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5185
AB  - The 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.
PB  - IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Toms
C3  - 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings
T1  - Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia)
SP  - 697
DO  - 10.17223/9785946217408/446
ER  - 

@conference{
author = "Stevanović, J. and Teslić, S. and Kharchenko, I.P. and Vuković, N. and Stojanović, Ksenija A.",
year = "2018",
abstract = "The 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.",
publisher = "IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Toms",
journal = "10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings",
title = "Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia)",
pages = "697",
doi = "10.17223/9785946217408/446"
}

Stevanović, J., Teslić, S., Kharchenko, I.P., Vuković, N.,& Stojanović, K. A.. (2018). Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia). in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings
IFPM and IHN of the Siberian Branch of the Russian Academy of Sciences, Toms., 697.
https://doi.org/10.17223/9785946217408/446

Stevanović J, Teslić S, Kharchenko I, Vuković N, Stojanović KA. Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia). in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings. 2018;:697.
doi:10.17223/9785946217408/446 .

Stevanović, J., Teslić, S., Kharchenko, I.P., Vuković, N., Stojanović, Ksenija A., "Organic geochemistry of crude oils from the Turija oil field (SE Pannonian Basin, Serbia)" in 10th International Conference “Oil and Gas Chemistry”, Tomsk, Russia, October 01-05, 2018. Proceedings (2018):697,
https://doi.org/10.17223/9785946217408/446 . .

TY  - JOUR
AU  - Dimitrijevic, S. P.
AU  - Anđić, Zoran
AU  - Kamberović, Željko
AU  - Dimitrijevic, S. B.
AU  - Vuković, N.
PY  - 2014
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/1641
AB  - The paper presents an improved process for recycling of silver-plate brass housing. Silver and copper are recovered with a purity of 99.99 % and 99.90 %, respectively, with the aim of obtaining materials of higher value using additional procedures based on the same process and equipment. The novel approach with subsequent electrorefining yields copper of 99.99 % purity with BS EN 1978:1998 (Cu-CATH-1) quality and is referred to as LME grade A. Additional processing of silver results in superfine, micro-sized Ag powder with partie size from 0.14 to 1.13 mu m and purity of 99.999 %. Copper electrorefining tests were performed using 1.50 dm(3) of synthetic electrolyte in a 2 dm(3) electrolytic cell. Effects of current density and electrolyte composition were investigated. Optimal current density for the first and second refining was 120 A/m(2) and 200 A/m(2), respectively. Additional refining of silver was performed by chemical reduction from an aqueous solution. Optimal results were obtained with ascorbic acid as a reduction agent in concentration of 0.1 mol/dm(3) and polyvinylpyrrolidon as a protective agent in concentration of 2 % by mass. The investigation results could be adopted into production.
PB  - Bulgarian Acad Science, Sofia
T2  - Bulgarian Chemical Communications
T1  - Recycling of silver-plated brass for production of high purity copper and ultrafine silver powder for electric contacts
VL  - 46
IS  - 4
SP  - 814
EP  - 824
UR  - https://hdl.handle.net/21.15107/rcub_cherry_1641
ER  - 

@article{
author = "Dimitrijevic, S. P. and Anđić, Zoran and Kamberović, Željko and Dimitrijevic, S. B. and Vuković, N.",
year = "2014",
abstract = "The paper presents an improved process for recycling of silver-plate brass housing. Silver and copper are recovered with a purity of 99.99 % and 99.90 %, respectively, with the aim of obtaining materials of higher value using additional procedures based on the same process and equipment. The novel approach with subsequent electrorefining yields copper of 99.99 % purity with BS EN 1978:1998 (Cu-CATH-1) quality and is referred to as LME grade A. Additional processing of silver results in superfine, micro-sized Ag powder with partie size from 0.14 to 1.13 mu m and purity of 99.999 %. Copper electrorefining tests were performed using 1.50 dm(3) of synthetic electrolyte in a 2 dm(3) electrolytic cell. Effects of current density and electrolyte composition were investigated. Optimal current density for the first and second refining was 120 A/m(2) and 200 A/m(2), respectively. Additional refining of silver was performed by chemical reduction from an aqueous solution. Optimal results were obtained with ascorbic acid as a reduction agent in concentration of 0.1 mol/dm(3) and polyvinylpyrrolidon as a protective agent in concentration of 2 % by mass. The investigation results could be adopted into production.",
publisher = "Bulgarian Acad Science, Sofia",
journal = "Bulgarian Chemical Communications",
title = "Recycling of silver-plated brass for production of high purity copper and ultrafine silver powder for electric contacts",
volume = "46",
number = "4",
pages = "814-824",
url = "https://hdl.handle.net/21.15107/rcub_cherry_1641"
}

Dimitrijevic, S. P., Anđić, Z., Kamberović, Ž., Dimitrijevic, S. B.,& Vuković, N.. (2014). Recycling of silver-plated brass for production of high purity copper and ultrafine silver powder for electric contacts. in Bulgarian Chemical Communications
Bulgarian Acad Science, Sofia., 46(4), 814-824.
https://hdl.handle.net/21.15107/rcub_cherry_1641

Dimitrijevic SP, Anđić Z, Kamberović Ž, Dimitrijevic SB, Vuković N. Recycling of silver-plated brass for production of high purity copper and ultrafine silver powder for electric contacts. in Bulgarian Chemical Communications. 2014;46(4):814-824.
https://hdl.handle.net/21.15107/rcub_cherry_1641 .

Dimitrijevic, S. P., Anđić, Zoran, Kamberović, Željko, Dimitrijevic, S. B., Vuković, N., "Recycling of silver-plated brass for production of high purity copper and ultrafine silver powder for electric contacts" in Bulgarian Chemical Communications, 46, no. 4 (2014):814-824,
https://hdl.handle.net/21.15107/rcub_cherry_1641 .