TY  - JOUR
AU  - Popović, Mina
AU  - Veličković, Zlate S.
AU  - Bogdanov, Jovica
AU  - Marinković, Aleksandar D.
AU  - Luna, Mariano Casas
AU  - Trajković, Isaak
AU  - Obradović, Nina
AU  - Pavlović, Vladimir B.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5238
AB  - In this study, the structure, morphology and composition of the synthesized magnetite/3D-printed wollastonite (3D_W/M) composite were characterized, and its adsorption performance with respect to As(V) and Cr(VI) were studied. Magnetite (MG) modified 3D printed wollastonite was obtained by two step procedure: modification of 3D_W with 3-aminoproylsilane (APTES) followed by controlled magnetite (MG) deposition to obtain 3D_W/M adsorbent. The structure/properties of 3D_W/M were confirmed by applying FTIR, XRD, TGD/DTA, and SEM analysis. The adsorption properties of hybrid adsorbents were carried out for As(V) and Cr(VI) removal-one relative to the initial pH value, the adsorbent mass, the temperature, and the adsorption time. Time-dependent adsorption study was best described by pseudo-second order equation, while Weber Morris analysis showed that intraparticle diffusion controled diffusional transport. Similar activation energy, 17.44 and 14.49 kJ•mol-1 for adsorption As(V) and Cr(VI) on 3D_W/M, respectively, indicated main contribution of physical adsorption. Determination of adsorption parameters was performed by applying different adsorption isotherm models, and the best fit was obtained using Freundlich model. The adsorption capacity of 24.16 and 29.6 mg g-1 for As(V) and Cr(VI) at 2o C, Co = 5.5 and 5.3 mg L-1, respectively, were obtained. Thermodynamic study indicated favourable process at a higher temperature. Preliminary fixed-bed column study and results fitting with Bohart-Adams, Yoon-Nelson, Thomas, and Modified dose-response model showed good agreement with results from the batch study.
PB  - International Institute for the Science of Sintering (IISS)
T2  - Science of Sintering
T1  - Removal of the As(V) and Cr(VI) from the Water Using Magnetite/3D-Printed Wollastonite Hybrid Adsorbent
VL  - 54
IS  - 1
SP  - 105
EP  - 124
DO  - 10.2298/SOS2201105P
ER  - 

@article{
author = "Popović, Mina and Veličković, Zlate S. and Bogdanov, Jovica and Marinković, Aleksandar D. and Luna, Mariano Casas and Trajković, Isaak and Obradović, Nina and Pavlović, Vladimir B.",
year = "2022",
abstract = "In this study, the structure, morphology and composition of the synthesized magnetite/3D-printed wollastonite (3D_W/M) composite were characterized, and its adsorption performance with respect to As(V) and Cr(VI) were studied. Magnetite (MG) modified 3D printed wollastonite was obtained by two step procedure: modification of 3D_W with 3-aminoproylsilane (APTES) followed by controlled magnetite (MG) deposition to obtain 3D_W/M adsorbent. The structure/properties of 3D_W/M were confirmed by applying FTIR, XRD, TGD/DTA, and SEM analysis. The adsorption properties of hybrid adsorbents were carried out for As(V) and Cr(VI) removal-one relative to the initial pH value, the adsorbent mass, the temperature, and the adsorption time. Time-dependent adsorption study was best described by pseudo-second order equation, while Weber Morris analysis showed that intraparticle diffusion controled diffusional transport. Similar activation energy, 17.44 and 14.49 kJ•mol-1 for adsorption As(V) and Cr(VI) on 3D_W/M, respectively, indicated main contribution of physical adsorption. Determination of adsorption parameters was performed by applying different adsorption isotherm models, and the best fit was obtained using Freundlich model. The adsorption capacity of 24.16 and 29.6 mg g-1 for As(V) and Cr(VI) at 2o C, Co = 5.5 and 5.3 mg L-1, respectively, were obtained. Thermodynamic study indicated favourable process at a higher temperature. Preliminary fixed-bed column study and results fitting with Bohart-Adams, Yoon-Nelson, Thomas, and Modified dose-response model showed good agreement with results from the batch study.",
publisher = "International Institute for the Science of Sintering (IISS)",
journal = "Science of Sintering",
title = "Removal of the As(V) and Cr(VI) from the Water Using Magnetite/3D-Printed Wollastonite Hybrid Adsorbent",
volume = "54",
number = "1",
pages = "105-124",
doi = "10.2298/SOS2201105P"
}

Popović, M., Veličković, Z. S., Bogdanov, J., Marinković, A. D., Luna, M. C., Trajković, I., Obradović, N.,& Pavlović, V. B.. (2022). Removal of the As(V) and Cr(VI) from the Water Using Magnetite/3D-Printed Wollastonite Hybrid Adsorbent. in Science of Sintering
International Institute for the Science of Sintering (IISS)., 54(1), 105-124.
https://doi.org/10.2298/SOS2201105P

Popović M, Veličković ZS, Bogdanov J, Marinković AD, Luna MC, Trajković I, Obradović N, Pavlović VB. Removal of the As(V) and Cr(VI) from the Water Using Magnetite/3D-Printed Wollastonite Hybrid Adsorbent. in Science of Sintering. 2022;54(1):105-124.
doi:10.2298/SOS2201105P .

Popović, Mina, Veličković, Zlate S., Bogdanov, Jovica, Marinković, Aleksandar D., Luna, Mariano Casas, Trajković, Isaak, Obradović, Nina, Pavlović, Vladimir B., "Removal of the As(V) and Cr(VI) from the Water Using Magnetite/3D-Printed Wollastonite Hybrid Adsorbent" in Science of Sintering, 54, no. 1 (2022):105-124,
https://doi.org/10.2298/SOS2201105P . .

TY  - JOUR
AU  - Vorkapić, Miloš
AU  - Mladenović, Ivana
AU  - Ivanov, Toni
AU  - Kovačević, Aleksandar
AU  - Mohammad Sakib, Hasan
AU  - Aleksandar, Simonović
AU  - Trajković, Isaak
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5363
AB  - Five series of specimens with two different print orientations (−45/45 and 0/90) and two print layer thicknesses (0.1 and 0.2 mm) were made. In total 60 specimens with 100% filament infill were made. One specimen series (20 pieces) was isolated as a reference or thermally untreated. Before the thermal treatment (annealing), two specimen moulding methods were used: NaCl powder (granulation 63 mm: 20 pieces) and Calcium Sulphate (Gypsum: 20 pieces). During the annealing, specimens immersed in NaCl powder were heated in a drying oven to the filament melting point (for PLA: 200°C, with a duration interval of 30 min), while the treatment of the heated specimens in gypsum was performed at a temperature of around 190°C, with duration interval of 3 h with the observed temperature inside the mould of about 100°C. An ultrasonic bath and a drying oven were used in the gypsum treatment. Temperature measurement and control during both annealing treatments were performed using a thermal imaging camera, while the temperature control inside the drying oven was performed using a digital thermometer. After treatment, the specimens in the moulds were cooled at room temperature, and the dimensions of annealing and untreated specimens were controlled. Surface morphology was characterised using scanning electron microscopy (SEM). The SEM analysis reveals improved internal structure after heat treatment of the PLA specimens. These results show that the investigated specimens after heat treatments had better structural properties than the referent specimens. Tensile testing on a universal testing machine in compliance with the ASTM D638 standard was also performed. The referent PLA specimen with −45/45 and layer thickness of 0.1 mm had the highest tensile stress value (64.08 MPa) while the specimen with minimal tensile stress value before fracture was 0/90, 0.2 mm (54.81 MPa). Heat treatment in gypsum showed the most significant increase in strength with −45/45 (0.1 mm) being the strongest (71.66 MPa) while the strongest specimen treated in sodium chloride was −45/45 (0.1 mm) with maximum tensile stress of 70.08 MPa. The mechanical characteristics of the PLA were characterised using the Vickers microhardness tester. The PLA microhardness value was calculated according to standards ASTM E384 and ISO 6507. The referent PLA specimen with −45/45 (0.2 mm) orientation shows the maximal microhardness value (125 MPa), and the minimal microhardness value was observed for the 0/90 (0.1 mm) orientation specimens (108 MPa). The heat treatment specimens in gypsum have a better hardness (185 MPa) than those treated in gypsum (165 MPa), with microhardness increasing by about 12%. The essence of the work is reflected in the additional filament processing to achieve a better structural and mechanical performance of the materials and reduce the anisotropy that is characteristic of 3D printing.
PB  - SAGE
T2  - Advances in Mechanical Engineering
T1  - Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds
VL  - 14
IS  - 8
SP  - 1
EP  - 15
DO  - 10.1177/16878132221120737
ER  - 

@article{
author = "Vorkapić, Miloš and Mladenović, Ivana and Ivanov, Toni and Kovačević, Aleksandar and Mohammad Sakib, Hasan and Aleksandar, Simonović and Trajković, Isaak",
year = "2022",
abstract = "Five series of specimens with two different print orientations (−45/45 and 0/90) and two print layer thicknesses (0.1 and 0.2 mm) were made. In total 60 specimens with 100% filament infill were made. One specimen series (20 pieces) was isolated as a reference or thermally untreated. Before the thermal treatment (annealing), two specimen moulding methods were used: NaCl powder (granulation 63 mm: 20 pieces) and Calcium Sulphate (Gypsum: 20 pieces). During the annealing, specimens immersed in NaCl powder were heated in a drying oven to the filament melting point (for PLA: 200°C, with a duration interval of 30 min), while the treatment of the heated specimens in gypsum was performed at a temperature of around 190°C, with duration interval of 3 h with the observed temperature inside the mould of about 100°C. An ultrasonic bath and a drying oven were used in the gypsum treatment. Temperature measurement and control during both annealing treatments were performed using a thermal imaging camera, while the temperature control inside the drying oven was performed using a digital thermometer. After treatment, the specimens in the moulds were cooled at room temperature, and the dimensions of annealing and untreated specimens were controlled. Surface morphology was characterised using scanning electron microscopy (SEM). The SEM analysis reveals improved internal structure after heat treatment of the PLA specimens. These results show that the investigated specimens after heat treatments had better structural properties than the referent specimens. Tensile testing on a universal testing machine in compliance with the ASTM D638 standard was also performed. The referent PLA specimen with −45/45 and layer thickness of 0.1 mm had the highest tensile stress value (64.08 MPa) while the specimen with minimal tensile stress value before fracture was 0/90, 0.2 mm (54.81 MPa). Heat treatment in gypsum showed the most significant increase in strength with −45/45 (0.1 mm) being the strongest (71.66 MPa) while the strongest specimen treated in sodium chloride was −45/45 (0.1 mm) with maximum tensile stress of 70.08 MPa. The mechanical characteristics of the PLA were characterised using the Vickers microhardness tester. The PLA microhardness value was calculated according to standards ASTM E384 and ISO 6507. The referent PLA specimen with −45/45 (0.2 mm) orientation shows the maximal microhardness value (125 MPa), and the minimal microhardness value was observed for the 0/90 (0.1 mm) orientation specimens (108 MPa). The heat treatment specimens in gypsum have a better hardness (185 MPa) than those treated in gypsum (165 MPa), with microhardness increasing by about 12%. The essence of the work is reflected in the additional filament processing to achieve a better structural and mechanical performance of the materials and reduce the anisotropy that is characteristic of 3D printing.",
publisher = "SAGE",
journal = "Advances in Mechanical Engineering",
title = "Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds",
volume = "14",
number = "8",
pages = "1-15",
doi = "10.1177/16878132221120737"
}

Vorkapić, M., Mladenović, I., Ivanov, T., Kovačević, A., Mohammad Sakib, H., Aleksandar, S.,& Trajković, I.. (2022). Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds. in Advances in Mechanical Engineering
SAGE., 14(8), 1-15.
https://doi.org/10.1177/16878132221120737

Vorkapić M, Mladenović I, Ivanov T, Kovačević A, Mohammad Sakib H, Aleksandar S, Trajković I. Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds. in Advances in Mechanical Engineering. 2022;14(8):1-15.
doi:10.1177/16878132221120737 .

Vorkapić, Miloš, Mladenović, Ivana, Ivanov, Toni, Kovačević, Aleksandar, Mohammad Sakib, Hasan, Aleksandar, Simonović, Trajković, Isaak, "Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds" in Advances in Mechanical Engineering, 14, no. 8 (2022):1-15,
https://doi.org/10.1177/16878132221120737 . .