TY  - JOUR
AU  - Nastasović, Aleksandra B.
AU  - Ignjatović, Nenad L.
AU  - Uskoković, Dragan
AU  - Markovic, Dana D.
AU  - Ekmescic, Bojana M.
AU  - Maksin, Danijela D.
AU  - Onjia, Antonije E.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5987
AB  - Inverse gas chromatography at infinite dilution was applied to determine the thermodynamic interactions of poly(l-lactide) (PLLA) and the composite of biphasic calcium phosphate and PLLA (BCP/PLLA). The specific retention volumes, , of 11 organic compounds of different chemical nature and polarity (non-polar, donor or acceptor) were determined in the temperature range of 308-378 K for PLLA and 308-398 K for BCP/PLLA. The weight fraction activity coefficients of test sorbates, , and the Flory-Huggins interaction parameters, , were estimated and discussed in terms of interactions of the sorbates with PLLA and BCP/PLLA. Also, the partial molar free energy, , the partial molar heat of mixing, , the sorption molar free energy, , the sorption enthalpy, , and the sorption entropy, , were analyzed. A different chromatographic behavior of the two investigated samples, PLLA and BCP/PLLA, was observed. The values of indicated n-alkanes, diethyl ether, tetrahydrofurane (THF), cyclohexane, benzene, dioxane (except for 338 K), and ethyl acetate (EtAc) (except for 338 K) as non-solvents, and chloroform (CHCl3) as good solvent (except for 378 K) for PLLA. For BCP/PLLA, CHCl3, EtAc (for 378 K), dioxane (except for 378 K), and THF were indicated as good solvents.
T2  - Journal of Materials Science
T1  - Determination of thermodynamic interactions of polylactide and biphasic calcium phosphate/polylactidecomposite by inverse gas chromatography at infinite dilution
VL  - 49
IS  - 14
SP  - 5076
EP  - 5086
DO  - 10.1007/s10853-014-8214-3
ER  - 

@article{
author = "Nastasović, Aleksandra B. and Ignjatović, Nenad L. and Uskoković, Dragan and Markovic, Dana D. and Ekmescic, Bojana M. and Maksin, Danijela D. and Onjia, Antonije E.",
year = "2014",
abstract = "Inverse gas chromatography at infinite dilution was applied to determine the thermodynamic interactions of poly(l-lactide) (PLLA) and the composite of biphasic calcium phosphate and PLLA (BCP/PLLA). The specific retention volumes, , of 11 organic compounds of different chemical nature and polarity (non-polar, donor or acceptor) were determined in the temperature range of 308-378 K for PLLA and 308-398 K for BCP/PLLA. The weight fraction activity coefficients of test sorbates, , and the Flory-Huggins interaction parameters, , were estimated and discussed in terms of interactions of the sorbates with PLLA and BCP/PLLA. Also, the partial molar free energy, , the partial molar heat of mixing, , the sorption molar free energy, , the sorption enthalpy, , and the sorption entropy, , were analyzed. A different chromatographic behavior of the two investigated samples, PLLA and BCP/PLLA, was observed. The values of indicated n-alkanes, diethyl ether, tetrahydrofurane (THF), cyclohexane, benzene, dioxane (except for 338 K), and ethyl acetate (EtAc) (except for 338 K) as non-solvents, and chloroform (CHCl3) as good solvent (except for 378 K) for PLLA. For BCP/PLLA, CHCl3, EtAc (for 378 K), dioxane (except for 378 K), and THF were indicated as good solvents.",
journal = "Journal of Materials Science",
title = "Determination of thermodynamic interactions of polylactide and biphasic calcium phosphate/polylactidecomposite by inverse gas chromatography at infinite dilution",
volume = "49",
number = "14",
pages = "5076-5086",
doi = "10.1007/s10853-014-8214-3"
}

Nastasović, A. B., Ignjatović, N. L., Uskoković, D., Markovic, D. D., Ekmescic, B. M., Maksin, D. D.,& Onjia, A. E.. (2014). Determination of thermodynamic interactions of polylactide and biphasic calcium phosphate/polylactidecomposite by inverse gas chromatography at infinite dilution. in Journal of Materials Science, 49(14), 5076-5086.
https://doi.org/10.1007/s10853-014-8214-3

Nastasović AB, Ignjatović NL, Uskoković D, Markovic DD, Ekmescic BM, Maksin DD, Onjia AE. Determination of thermodynamic interactions of polylactide and biphasic calcium phosphate/polylactidecomposite by inverse gas chromatography at infinite dilution. in Journal of Materials Science. 2014;49(14):5076-5086.
doi:10.1007/s10853-014-8214-3 .

Nastasović, Aleksandra B., Ignjatović, Nenad L., Uskoković, Dragan, Markovic, Dana D., Ekmescic, Bojana M., Maksin, Danijela D., Onjia, Antonije E., "Determination of thermodynamic interactions of polylactide and biphasic calcium phosphate/polylactidecomposite by inverse gas chromatography at infinite dilution" in Journal of Materials Science, 49, no. 14 (2014):5076-5086,
https://doi.org/10.1007/s10853-014-8214-3 . .

TY  - JOUR
AU  - Markovic, Dana D.
AU  - Lekić, Branislava M.
AU  - Rajaković-Ognjanović, Vladana N.
AU  - Onjia, Antonije E.
AU  - Rajaković, Ljubinka V.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5871
AB  - Numerous regression approaches to isotherm parameters estimation appear in the literature. The real insight into the proper modeling pattern can be achieved only by testing methods on a very big number of cases. Experimentally, it cannot be done in a reasonable time, so the Monte Carlo simulation method was applied. The objective of this paper is to introduce and compare numerical approaches that involve different levels of knowledge about the noise structure of the analytical method used for initial and equilibrium concentration determination. Six levels of homoscedastic noise and five types of heteroscedastic noise precision models were considered. Performance of the methods was statistically evaluated based on median percentage error and mean absolute relative error in parameter estimates. The present study showed a clear distinction between two cases. When equilibrium experiments are performed only once, for the homoscedastic case, the winning error function is ordinary least squares, while for the case of heteroscedastic noise the use of orthogonal distance regression or Margarts percent standard deviation is suggested. It was found that in case when experiments are repeated three times the simple method of weighted least squares performed as well as more complicated orthogonal distance regression method.
T2  - Scientific World Journal
T1  - A New Approach in Regression Analysis for Modeling Adsorption Isotherms
DO  - 10.1155/2014/930879
ER  - 

@article{
author = "Markovic, Dana D. and Lekić, Branislava M. and Rajaković-Ognjanović, Vladana N. and Onjia, Antonije E. and Rajaković, Ljubinka V.",
year = "2014",
abstract = "Numerous regression approaches to isotherm parameters estimation appear in the literature. The real insight into the proper modeling pattern can be achieved only by testing methods on a very big number of cases. Experimentally, it cannot be done in a reasonable time, so the Monte Carlo simulation method was applied. The objective of this paper is to introduce and compare numerical approaches that involve different levels of knowledge about the noise structure of the analytical method used for initial and equilibrium concentration determination. Six levels of homoscedastic noise and five types of heteroscedastic noise precision models were considered. Performance of the methods was statistically evaluated based on median percentage error and mean absolute relative error in parameter estimates. The present study showed a clear distinction between two cases. When equilibrium experiments are performed only once, for the homoscedastic case, the winning error function is ordinary least squares, while for the case of heteroscedastic noise the use of orthogonal distance regression or Margarts percent standard deviation is suggested. It was found that in case when experiments are repeated three times the simple method of weighted least squares performed as well as more complicated orthogonal distance regression method.",
journal = "Scientific World Journal",
title = "A New Approach in Regression Analysis for Modeling Adsorption Isotherms",
doi = "10.1155/2014/930879"
}

Markovic, D. D., Lekić, B. M., Rajaković-Ognjanović, V. N., Onjia, A. E.,& Rajaković, L. V.. (2014). A New Approach in Regression Analysis for Modeling Adsorption Isotherms. in Scientific World Journal.
https://doi.org/10.1155/2014/930879

Markovic DD, Lekić BM, Rajaković-Ognjanović VN, Onjia AE, Rajaković LV. A New Approach in Regression Analysis for Modeling Adsorption Isotherms. in Scientific World Journal. 2014;.
doi:10.1155/2014/930879 .

Markovic, Dana D., Lekić, Branislava M., Rajaković-Ognjanović, Vladana N., Onjia, Antonije E., Rajaković, Ljubinka V., "A New Approach in Regression Analysis for Modeling Adsorption Isotherms" in Scientific World Journal (2014),
https://doi.org/10.1155/2014/930879 . .

TY  - JOUR
AU  - Markovski, Jasmina S.
AU  - Markovic, Dana D.
AU  - Đokić, Veljko R.
AU  - Mitrić, Miodrag
AU  - Ristić, Mirjana
AU  - Onjia, Antonije E.
AU  - Marinković, Aleksandar D.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5843
AB  - An efficient adsorbents for arsenate removal was developed by modification of calcined eggshell with goethite (calcined eggshell/goethite; sorbent 1), alpha-MnO2 (calcined eggshell/alpha-MnO2; sorbent 2) and hybride system goethite/alpha-MnO2 (calcined eggshell/goethite/alpha-MnO2; sorbent 3). Methods and processes for preparation of novel adsorbents were defined and obtained materials were characterized by BET, XRD, SEM and FTIR analysis. The influence of functionalization methods, solution pH, contact time, temperature, interfering ions and initial arsenate concentration on efficiencies of arsenate adsorption were studied in a batch system. Based on the orthogonal distance regression (ODR) fitting, using R-2, MARE and RMSRE statistical criteria, Langmuir and Sips equations were chosen for description of adsorption equilibriums on sorbents 1 and 3, respectively. The maximum adsorption capacities of 33.38 mg g(-1), 13.54 mg g(-1) and 47.04 mg g(-1) for sorbents 1-3, respectively, were obtained. Time-dependent study revealed that pseudo-second-order equation fitted well the kinetic data, while the Weber Morison model predicted intra-particle diffusion as main adsorption rate controlling step. Thermodynamic parameters indicated exothermic, feasible and spontaneous nature of adsorption process on sorbents I and 3. Results of Visual MINTEQ equilibrium speciation modeling program was used for studying pH, ionic strength and interfering ions influences on arsenate adsorption. (C) 2013 Elsevier B.V. All rights reserved.
T2  - Chemical Engineering Journal
T1  - Arsenate adsorption on waste eggshell modified by goethite, alpha-MnO2 and goethite/alpha-MnO2
VL  - 237
SP  - 430
EP  - 442
DO  - 10.1016/j.cej.2013.10.031
ER  - 

@article{
author = "Markovski, Jasmina S. and Markovic, Dana D. and Đokić, Veljko R. and Mitrić, Miodrag and Ristić, Mirjana and Onjia, Antonije E. and Marinković, Aleksandar D.",
year = "2014",
abstract = "An efficient adsorbents for arsenate removal was developed by modification of calcined eggshell with goethite (calcined eggshell/goethite; sorbent 1), alpha-MnO2 (calcined eggshell/alpha-MnO2; sorbent 2) and hybride system goethite/alpha-MnO2 (calcined eggshell/goethite/alpha-MnO2; sorbent 3). Methods and processes for preparation of novel adsorbents were defined and obtained materials were characterized by BET, XRD, SEM and FTIR analysis. The influence of functionalization methods, solution pH, contact time, temperature, interfering ions and initial arsenate concentration on efficiencies of arsenate adsorption were studied in a batch system. Based on the orthogonal distance regression (ODR) fitting, using R-2, MARE and RMSRE statistical criteria, Langmuir and Sips equations were chosen for description of adsorption equilibriums on sorbents 1 and 3, respectively. The maximum adsorption capacities of 33.38 mg g(-1), 13.54 mg g(-1) and 47.04 mg g(-1) for sorbents 1-3, respectively, were obtained. Time-dependent study revealed that pseudo-second-order equation fitted well the kinetic data, while the Weber Morison model predicted intra-particle diffusion as main adsorption rate controlling step. Thermodynamic parameters indicated exothermic, feasible and spontaneous nature of adsorption process on sorbents I and 3. Results of Visual MINTEQ equilibrium speciation modeling program was used for studying pH, ionic strength and interfering ions influences on arsenate adsorption. (C) 2013 Elsevier B.V. All rights reserved.",
journal = "Chemical Engineering Journal",
title = "Arsenate adsorption on waste eggshell modified by goethite, alpha-MnO2 and goethite/alpha-MnO2",
volume = "237",
pages = "430-442",
doi = "10.1016/j.cej.2013.10.031"
}

Markovski, J. S., Markovic, D. D., Đokić, V. R., Mitrić, M., Ristić, M., Onjia, A. E.,& Marinković, A. D.. (2014). Arsenate adsorption on waste eggshell modified by goethite, alpha-MnO2 and goethite/alpha-MnO2. in Chemical Engineering Journal, 237, 430-442.
https://doi.org/10.1016/j.cej.2013.10.031

Markovski JS, Markovic DD, Đokić VR, Mitrić M, Ristić M, Onjia AE, Marinković AD. Arsenate adsorption on waste eggshell modified by goethite, alpha-MnO2 and goethite/alpha-MnO2. in Chemical Engineering Journal. 2014;237:430-442.
doi:10.1016/j.cej.2013.10.031 .

Markovski, Jasmina S., Markovic, Dana D., Đokić, Veljko R., Mitrić, Miodrag, Ristić, Mirjana, Onjia, Antonije E., Marinković, Aleksandar D., "Arsenate adsorption on waste eggshell modified by goethite, alpha-MnO2 and goethite/alpha-MnO2" in Chemical Engineering Journal, 237 (2014):430-442,
https://doi.org/10.1016/j.cej.2013.10.031 . .

TY  - JOUR
AU  - Lekić, Branislava M.
AU  - Markovic, Dana D.
AU  - Rajaković-Ognjanović, Vladana N.
AU  - Đukić, Aleksandar R.
AU  - Rajaković, Ljubinka V.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5698
AB  - In this study, removal of arsenic ions using two industrial by-products as adsorbents is represented. Removal of As(III) and As(V) from water was carried out with industrial by-products: residual from the groundwater treatment process, iron-manganese oxide coated sand (IMOCS), and blast furnace slag from steel production (BFS), both inexpensive and locally available. In addition, the BFS was modified in order to minimise its deteriorating impact on the initial water quality. Kinetic and equilibrium studies were carried out using batch and fixed-bed column adsorption techniques under the conditions that are likely to occur in real water treatment systems. To evaluate the application for real groundwater treatment, the capacities of the selected materials were further compared to those exhibited by commercial sorbents, which were examined under the same experimental conditions. IMOCS was found to be a good and inexpensive sorbent for arsenic, while BFS and modified slag showed the highest affinity towards arsenic. All examined waste materials exhibited better sorption performances for As(V). The maximum sorption capacity in the batch reactor was obtained for blast furnace slag, 4040 mu gAs(V)/g.
T2  - Journal of Chemistry
T1  - Arsenic Removal from Water Using Industrial By-Products
DO  - 10.1155/2013/121024
ER  - 

@article{
author = "Lekić, Branislava M. and Markovic, Dana D. and Rajaković-Ognjanović, Vladana N. and Đukić, Aleksandar R. and Rajaković, Ljubinka V.",
year = "2013",
abstract = "In this study, removal of arsenic ions using two industrial by-products as adsorbents is represented. Removal of As(III) and As(V) from water was carried out with industrial by-products: residual from the groundwater treatment process, iron-manganese oxide coated sand (IMOCS), and blast furnace slag from steel production (BFS), both inexpensive and locally available. In addition, the BFS was modified in order to minimise its deteriorating impact on the initial water quality. Kinetic and equilibrium studies were carried out using batch and fixed-bed column adsorption techniques under the conditions that are likely to occur in real water treatment systems. To evaluate the application for real groundwater treatment, the capacities of the selected materials were further compared to those exhibited by commercial sorbents, which were examined under the same experimental conditions. IMOCS was found to be a good and inexpensive sorbent for arsenic, while BFS and modified slag showed the highest affinity towards arsenic. All examined waste materials exhibited better sorption performances for As(V). The maximum sorption capacity in the batch reactor was obtained for blast furnace slag, 4040 mu gAs(V)/g.",
journal = "Journal of Chemistry",
title = "Arsenic Removal from Water Using Industrial By-Products",
doi = "10.1155/2013/121024"
}

Lekić, B. M., Markovic, D. D., Rajaković-Ognjanović, V. N., Đukić, A. R.,& Rajaković, L. V.. (2013). Arsenic Removal from Water Using Industrial By-Products. in Journal of Chemistry.
https://doi.org/10.1155/2013/121024

Lekić BM, Markovic DD, Rajaković-Ognjanović VN, Đukić AR, Rajaković LV. Arsenic Removal from Water Using Industrial By-Products. in Journal of Chemistry. 2013;.
doi:10.1155/2013/121024 .

Lekić, Branislava M., Markovic, Dana D., Rajaković-Ognjanović, Vladana N., Đukić, Aleksandar R., Rajaković, Ljubinka V., "Arsenic Removal from Water Using Industrial By-Products" in Journal of Chemistry (2013),
https://doi.org/10.1155/2013/121024 . .

TY  - JOUR
AU  - Rajaković, Ljubinka V.
AU  - Markovic, Dana D.
AU  - Rajaković-Ognjanović, Vladana N.
AU  - Antanasijević, Davor Z.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5225
AB  - The analytical properties of an analytical method must be evaluated through validation protocols. Beside specificity and/or selectivity, linearity of calibration, repeatability and accuracy, the most important parameters are: LOD (limit of detection) and LOQ (limit of quantification). Through these limits, it is possible to define the smallest concentration of analyte that can be reliably detected and quantified. To establish these limits, an analyst should apply several estimation methods and test a large number of sample replicates. It is difficult to make a compromise between complex statistical programs and the simple analytical demand to have reliable analytical parameters. The differences and equivalency of estimation methods and approaches for analytical limits could be overcome by an experimental comparison. In this paper, the focus is the LOD of inductively coupled plasma-mass spectrometry (ICP-MS) measurements employed for the determination of arsenic. The current approaches for the calculation of the LOD are summarized and critically discussed. (C) 2012 Elsevier B.V. All rights reserved.
T2  - Talanta
T1  - Review: The approaches for estimation of limit of detection for ICP-MS trace analysis of arsenic
VL  - 102
IS  - SI
SP  - 79
EP  - 87
DO  - 10.1016/j.talanta.2012.08.016
ER  - 

@article{
author = "Rajaković, Ljubinka V. and Markovic, Dana D. and Rajaković-Ognjanović, Vladana N. and Antanasijević, Davor Z.",
year = "2012",
abstract = "The analytical properties of an analytical method must be evaluated through validation protocols. Beside specificity and/or selectivity, linearity of calibration, repeatability and accuracy, the most important parameters are: LOD (limit of detection) and LOQ (limit of quantification). Through these limits, it is possible to define the smallest concentration of analyte that can be reliably detected and quantified. To establish these limits, an analyst should apply several estimation methods and test a large number of sample replicates. It is difficult to make a compromise between complex statistical programs and the simple analytical demand to have reliable analytical parameters. The differences and equivalency of estimation methods and approaches for analytical limits could be overcome by an experimental comparison. In this paper, the focus is the LOD of inductively coupled plasma-mass spectrometry (ICP-MS) measurements employed for the determination of arsenic. The current approaches for the calculation of the LOD are summarized and critically discussed. (C) 2012 Elsevier B.V. All rights reserved.",
journal = "Talanta",
title = "Review: The approaches for estimation of limit of detection for ICP-MS trace analysis of arsenic",
volume = "102",
number = "SI",
pages = "79-87",
doi = "10.1016/j.talanta.2012.08.016"
}

Rajaković, L. V., Markovic, D. D., Rajaković-Ognjanović, V. N.,& Antanasijević, D. Z.. (2012). Review: The approaches for estimation of limit of detection for ICP-MS trace analysis of arsenic. in Talanta, 102(SI), 79-87.
https://doi.org/10.1016/j.talanta.2012.08.016

Rajaković LV, Markovic DD, Rajaković-Ognjanović VN, Antanasijević DZ. Review: The approaches for estimation of limit of detection for ICP-MS trace analysis of arsenic. in Talanta. 2012;102(SI):79-87.
doi:10.1016/j.talanta.2012.08.016 .

Rajaković, Ljubinka V., Markovic, Dana D., Rajaković-Ognjanović, Vladana N., Antanasijević, Davor Z., "Review: The approaches for estimation of limit of detection for ICP-MS trace analysis of arsenic" in Talanta, 102, no. SI (2012):79-87,
https://doi.org/10.1016/j.talanta.2012.08.016 . .