| 1. |
- Li, Jing, et al.
(författare)
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Fabrication and application of polyurea formaldehyde-bioasphalt microcapsules as a secondary modifier for the preparation of high self-healing rate SBS modified asphalt
- 2020
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Ingår i: Construction and Building Materials. - : Elsevier. - 0950-0618 .- 1879-0526. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- In this study, microcapsules were prepared from polyurea formaldehyde (as microcapsules wall) and bio-asphalt (as microcapsules core) and were in turn applied to prepare microcapsule-styrene-butadiene styrene (microcapsule/SBS) modified asphalt. When the asphalt wall was broken, the bio-asphalt (core) drifted out and was well blended with the SBS modified asphalt to repair the damaged gap, thereby improving the self-healing ability of the pristine SBS modified asphalt. Ductility test showed that the healing rate of microcapsule/SBS modified asphalt was much greater than that of pure SBS modified asphalt. Dynamic shear rheometer and multi-stress creep recovery tests revealed that microcapsule/SBS modified asphalt exhibited better viscoelasticity, high temperature stability (by thermogravimetric analysis) and rutting resistance than pure SBS modified asphalt attributed to the even dispersion of microcapsules in SBS as confirmed by fluorescent microscopy. Compared with the pure SBS modified asphalt, the storage modulus and loss modulus of 0.4% microcapsule/SBS modified asphalt increased by 24.8% and 17.7% at 46 degrees C, respectively. Scanning electron microscopy and transmission electron microscopy analyses revealed spherical morphology of the microcapsules with wrinkled depressions on the surface, while the wall of microcapsule coated the core. This study can be envisioned of great promise for the preparation of alternative types of modified asphalt for practical applications in construction and highway industries.
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| 2. |
- Li, Jing, et al.
(författare)
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Preparation and properties of modified graphene oxide incorporated waterborne polyurethane acrylate
- 2019
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Ingår i: Polymer international. - : Society of Chemical Industry. - 0959-8103 .- 1097-0126. ; 68:6, s. 1091-1101
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a new modifier (KPG) was prepared by modifying graphene oxide with gamma-glycidoxypropyl trimethoxysilane (KH560) and polydimethylsiloxane (PDMS). KPG was in turn added to aqueous urethane acrylate for the fabrication of waterborne polyurethane polyacrylate emulsion modified with KH560-PDMS composite (KPG/WPUA). Textural characterizations of the KPG/WPUA coating were achieved via Fourier transform infrared, SEM, TGA and AFM techniques, which revealed that the KPG/WPUA film possessed a smooth surface. The synthesized KPG/WPUA films were tested for mechanical properties, hydrophobicity and acid/water corrosion performance which suggested their highly hydrophobic surface. KPG/WPUA with 0.1% KPG showed a contact angle of 118.35 degrees, 30.35 degrees higher than that of pristine WPUA. The KPG/WPUA film exhibited higher thermal stability, i.e. a 5% weight loss temperature of 305 degrees C, which was 30 degrees C higher than that of pristine WPUA film. The Young's modulus and elongation at break of the KPG/WPUA film were 34.1 MPa and 74.88% respectively, which were higher than that of WPUA film. Furthermore, KPG/WPUA films exhibited greater resistance (without obvious blistering and the white spotting phenomenon) to H2O2, HCl and water corrosion than pristine WPUA. The superior performance of KPG/WPUA films was attributed to the network chain structure formed upon the introduction of KPG into WPUA. The outstanding performance of KPG/WPUA films in terms of mechanical properties, thermal stability and high resistance to acidic and water corrosion makes them interesting alternative contenders for target applications. (c) 2019 Society of Chemical Industry
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| 3. |
- Meng, Fei, et al.
(författare)
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Analysis of Virgin Asphalt Brands via the Integrated Application of FTIR and Gel Permeation Chromatography
- 2020
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Ingår i: Arabian journal for science and engineering. - : Springer. - 2193-567X .- 2191-4281. ; 45, s. 7999-8009
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Tidskriftsartikel (refereegranskat)abstract
- Counterfeit asphalts have often been deliberately adulterated to reduce costs, which has seriously impeded the development of road and highway construction. In this study, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and gel permeation chromatography (GPC) were applied in combination to explore a fast, accurate, low-cost and efficient method to better identify the brand and quality of asphalt. Results revealed that ATR-FTIR spectra of seven brands of asphalt were basically identical, while they differ in benzene ring substituent content and (-CH2-)n (n >= 4) content. The fingerprint intervals of virgin asphalt were 1770-1636 cm-1, 1060-985 cm-1 and 920-690 cm-1. The aging degree of the same brand of asphalt was identified by 1770-1636 cm-1 and 1060-985 cm-1, while 920-690 cm-1 range was used to identify the fingerprint interval of the original asphalt brand. GPC analysis revealed that the large molecular size (LMS) content of original Fu Lian and Shuang Long asphalt brands greatly differed which were not identified by FTIR. Owing to the thermal oxidation, the LMS content of the same brand of virgin asphalt increased by 4-6% after short-term aging. The present study based on the integrated operation of GPC-FTIR for the fast and accurate recognition and distinguishing between different brands of asphalts could be of potential practical applications.
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| 4. |
- Muhammad, Yaseen, et al.
(författare)
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Boosting the hydrodesulfurization of dibenzothiophene efficiency of Mn decorated (Co/Ni)-Mo/Al2O3 catalysts at mild temperature and pressure by coupling with phosphonium based ionic liquids
- 2019
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 375
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Tidskriftsartikel (refereegranskat)abstract
- Hydrodesulfurization (HDS) of fuel oils is the most viable and commercially acceptable approach operated under harsh operating conditions. To avoid harsh reaction conditions, this study is designed on the HDS of dibenzothiophene (DBT) under the combined effect of five types of Phosphonium based ionic liquids (PILs) i.e. [C4H9)3(C14H29)P]Br, [(C8H17)(C4H9)3P]Br [(C4H9)4P]Cl, [BMIM]PF6 and [C4H9)3(C16H33)P]Br with 5 wt% Mn promoted (Co or Ni)-Mo/Al2O3 catalysts at extremely ambient temperature and pressure. Catalysts were prepared by wet impregnation technique followed by their sulfidation (30% CS2 in cyclohexane) and textural characterization via SEM, BET, PXRD and XPS techniques. Catalytic activity results indicated that DBT conversion was boosted from 24% (by mere Mn-Ni-Mo/Al2O3) to 84% (by Mn-Ni-Mo/Al2O3 coupled with 10 g of [(C4H9)3(C16H33)P]Br) at 3 MPa H2 pressure, 120 °C and 4 h reaction time. Among the five types of PILs, the enhancement in HDS activity combined with solid catalyst was found dependent on the type and length of cation chain. The enhanced DBT conversion caused by Mn-Ni-Mo/Al2O3 solid catalyst coupled with IL was envisioned to be due the synergy between hydrogenation reaction (by the former) and extractive desulfurization (by the later) with an overall HDS activity order of: Mn-Ni-Mo/Al2O3 > Mn-Co-Mo/Al2O3 > Ni-Mo/Al2O3 > Co-Mo/Al2O3. HDS products were analyzed by GC-MS and possible reaction route was anticipated. This study successfully discovered and elaborated of boosting of HDS of DBT at extremely mild operation conditions under the integrated effect of solid catalyst and PILs and hence can be pragmatically envisaged as an alternative approach for fuel oils desulfurization and other similar reactions on industrial level.
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| 5. |
- Muhammad, Yaseen, et al.
(författare)
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Hydrodesulfurization of dibenzothiophene using Pd-promoted Co–Mo/Al2O3 and Ni–Mo/Al2O3 catalysts coupled with ionic liquids at ambient operating conditions
- 2019
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:18, s. 10371-10385
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur compounds in fuel oils are a major source of atmospheric pollution. This study is focused on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) via the coupled application of 0.5 wt% Pd-loaded Co–Mo/Al2O3 and Ni–Mo/Al2O3 catalysts with ionic liquids (ILs) at ambient temperature (120 °C) and pressure (1 MPa H2). The enhanced HDS activity of the solid catalysts coupled with [BMIM]BF4, [(CH3)4N]Cl, [EMIM]AlCl4, and [(n-C8H17)(C4H9)3P]Br was credited to the synergism between hydrogenation by the former and extractive desulfurization and better H2 transport by the latter, which was confirmed by DFT simulation. The Pd-loaded catalysts ranked highest by activity i.e. Pd–Ni–Mo/Al2O3 > Pd–Co–Mo/Al2O3 > Ni–Mo/Al2O3 > Co–Mo/Al2O3. With mild experimental conditions of 1 MPa H2 pressure and 120 °C temperature and an oil : IL ratio of 10 : 3.3, DBT conversion was enhanced from 21% (by blank Ni–Mo/Al2O3) to 70% by Pd–Ni–Mo/Al2O3 coupled with [(n-C8H17)(C4H9)3P]Br. The interaction of polarizable delocalized bonds (in DBT) and van der Waals forces influenced the higher solubility in ILs and hence led to higher DBT conversion. The IL was recycled four times with minimal loss of activity. Fresh and spent catalysts were characterized by FESEM, ICP-MS, EDX, XRD, XPS and BET surface area techniques. GC-MS analysis revealed biphenyl as the major HDS product. This study presents a considerable advance to the classical HDS processes in terms of mild operating conditions, cost-effectiveness, and simplified mechanization, and hence can be envisaged as an alternative approach for fuel oil processing.
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| 6. |
- Su, Zhibin, et al.
(författare)
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Preparation and properties of aminated graphene fiber incorporated modified asphalt
- 2019
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Ingår i: Construction and Building Materials. - : Elsevier. - 0950-0618 .- 1879-0526. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- The inert nature of polyacrylonitrile (PAN) fiber limits the development of fiber asphalt pavement, which can however be tackled by modifying PAN. In this paper, PAN was modified via self-polymerization of dopamine and covalent grafting of aminated graphene, which were in turn used to prepare three kinds of modified asphalt. Dynamic shear rheometer (DSR) tests showed that the aminated graphene modified fiber based asphalt had better viscoelasticity and resistance to permanent deformation than the pristine fiber added asphalt. 3% NH2-GNPs/D-PAN modified asphalt exhibited about 8% higher G* than 3% PAN modified asphalt at a fixed shear frequency. The aminated graphene modified asphalt exhibited enhanced hydrophobicity, adhesion work and water resistance (increased by 14%) than unmodified PAN fiber added asphalt as determined via contact angle measurement. Trabecular bending test and water-immersed Marshall stability test showed that NH2-GNPs/D-PAN incorporated modified asphalt mixture realized the best cracking resistance at low temperature and water damage resistance, which is consistent with the result of DSR and contact angle tests. FT-IR characterization confirmed the successful grafting of amino group onto graphene oxide and that graphite oxide was reduced to graphene. The fiber structure and successful grafting of aminated graphene onto the fiber surface in the PAN modified asphalt was further characterized and confirmed by SEM and AFM.
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| 7. |
- Subhan, Sidra, et al.
(författare)
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Fabrication of MnO2 NPs incorporated UiO-66 for the green and efficient oxidative desulfurization and denitrogenation of fuel oils
- 2021
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier. - 2213-3437. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Manganese oxide nanoparticles (MnO2 NPs) are deposited over Zr-based UiO-66 molecular organic framework (MOF) resulting in MnO2/UiO-66 composite which is oxidized with NaClO for the catalytic oxidative desulfurization and denitrogenation of fuel oil. The as-synthesized composites were characterized via FE-SEM, EDX, BET, XPS and FT-IR techniques which confirmed the uniform deposition of MnO2 NPs and resulted in increased surface area and average mesoporous volume of pristine UiO-66. Catalytic results showed that MnO2/UiO-66 oxidized 2000 ppm of DBT (347 ppm Sulfur) and pyridine (502.8 ppm Nitrogen) in 3 min at O/S and O/N of 4, 0.06 g/15 mL catalyst dose and 25 °C. The mechanism behind the super-fast and highly efficacious performance of MnO2/UiO-66 is the ideal synergy among Mn4+, Zr4+ and NaClO species, which produced strong oxidizing •OH and •O2− radicals. Under the optimized reaction parameters, much higher removal of DBT and pyridine (100%) was achieved as compared to those of BT, 4,6-DMDBT, indole, and carbazole up to 6th cycles. This study provided important oxidant-catalyst system i.e. MnO2/UiO-66-NaClO for the highly efficacious, super-fast, and time and cost-effective alternative to the large scale oxidative desulfurization and denitrogenation of fuel oils.
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| 8. |
- Subhan, Sidra, et al.
(författare)
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Studies on the Selection of a Catalyst-Oxidant System for the Energy-Efficient Desulfurization and Denitrogenation of Fuel Oil at Mild Operating Conditions
- 2019
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 33:9, s. 8423-8439
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Tidskriftsartikel (refereegranskat)abstract
- This study reports the selection of an ideal catalyst–oxidant system for the energy-efficient catalytic oxidative desulfurization (CODS) of dibenzothiophene (DBT) and denitrogenation (CODN) of pyridine over Mn–Co–Mo/Al2O3 and acid-functionalized 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl/ZnCl2) ionic liquid (IL) catalysts using H2O2 and NaClO as oxidants. The NaClO–catalyst system realized 100% CODS/CODN activity within 15 min at 25 °C at comparatively low activation energies of 4.9 and 5.4 kJ/mol for DBT and pyridine, respectively, under optimal conditions of oxidant-to-sulfur ratio of 4, oxidant-to-nitrogen ratio of 8, ionic liquid-to-oil ratio of 1.5/5, and 0.1 g of Mn–Co–Mo/Al2O3 catalyst for 15 mL of model fuel. Both catalytic activity and kinetics results revealed a NaClO–catalyst system with greater efficiency and lesser energy requirements than a H2O2–catalyst system, and hence the former realized enhanced CODS and CODN than the latter. Furthermore, the Mn–Co–Mo/Al2O3 catalyst favored CODS, while [Bmim]Cl/ZnCl2 possessed greater affinity for the CODN process, owing to the stronger nucleophilic interaction of the cationic species in IL toward hindered nitrogen compounds. Further justification for the CODS and CODN activities and textural characterization of the fresh and spent catalysts were provided by PXRD, XPS, SEM, EDX elemental mapping, and BET surface area characterizations. Based on the results, this study is potentially viable owing to its environmental greenness, enhancement in the calorific value of the final fuel, and genially benignant application in energy consumption via mild operating conditions and hence can be envisaged as a practicable alternative approach in industrial processing of fuel oils.
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| 9. |
- Subhan, Sidra, et al.
(författare)
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Ultra-fast and highly efficient catalytic oxidative desulfurization of dibenzothiophene at ambient temperature over low Mn loaded Co-Mo/Al2O3 and Ni-Mo/Al2O3 catalysts using NaClO as oxidant
- 2019
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Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 237, s. 793-805
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Tidskriftsartikel (refereegranskat)abstract
- This study reports the ultra-fast and highly efficient oxidative desulfurization (ODS) of dibenzothiophene (DBT) at room temperature over low Mn (0.5 wt%) incorporated Co-Mo/Al2O3 and Ni-Mo/Al(2)O(3 )catalysts using NaClO as oxidant. The effect of disparate operating parameters i.e. mode of catalyst preparation, DBT initial concentration, reaction time, temperature, catalyst and oxidant dose, oxidant type and reaction pH on oxidation process was investigated. Results revealed that remarkably high and ultra-fast A DBT conversion of 100% was achieved within 5 min utilizing 15 mL sample of 2000 ppm (347 ppm sulfur), 0.1 mL of 0.138 M NaClO (O/S6.6 mol/mol), 0.1 g Mn-Co-Mo/Al2O3 catalyst at pH 12, and 25 degrees C reaction temperature. A reaction mechanism for the highly efficient ODS activity of Mn promoted catalysts accredited to the synergistic effect of Mn active phase and high oxidizing power of NaClO was proposed. An overall ODS catalytic activity order of: Mn-Co-Mo/Al2O3 > Mn-Ni-Mo/Al2O3 > Co-Mo/Al2O3 > Ni-Mo/Al2O3 > Mo/Al2O3 was observed. Discernment of the surface morphology and textural properties of fresh and spent catalysts were characterized using Scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy dispersive X-Ray (EDX), and BET surface area analysis which helped in evaluating the catalytic activity results. Due to ultra-fast and highly efficacious nature, simple and safe mechanization, cost effectiveness, and operation at ambient reaction conditions, this study can be envisaged as an effective approach for the ODS of fuel oils on industrial level.
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| 10. |
- Zhu, Ying, et al.
(författare)
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Effects of divalent copper on tetracycline degradation and the proposed transformation pathway
- 2020
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 27:5, s. 5155-5167
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Tidskriftsartikel (refereegranskat)abstract
- To reveal the characteristics of tetracycline (TC) photocatalytic degradation under Cu(II) coexistence, effects of Cu(II) on TC photocatalytic degradation by ZnO nanoparticles (ZnO NPs) as a function of pH, humic acid (HA), and initial Cu(II) concentration were investigated. Interaction of TC with Cu(II) in the treatment process was analyzed by circular dichroism (CD) spectroscopy, while TC degradation pathway was investigated by high-performance liquid chromatography-mass spectrometry. Sixty-five percent and ninety-one percent TC degradation within 60 min in the absence and presence of Cu(II), respectively, was reported. Both adsorption and photocatalytic degradation of TC under Cu(II) coexistence increased with increasing pH from 3 to 6, while decreased with further increase in pH. HA inhibited the degradation of TC by ZnO NPs both in the presence as well absence of Cu(II), while TC degradation decreased from 91 to 73% and from 73 to 37% in the presence and absence of Cu(II), respectively. TC degradation by ZnO NPs first increased then decreased with increasing Cu(II). Maximum TC degradation (about 94%) was obtained in the optimum concentration range of Cu(II) (0.05-0.15 mmol/L). In addition, there was a lag effect between TC adsorption and degradation on ZnO NPs. TC degradation was improved via Cu(II)-TC surface complexation and followed N-demethylation and hydroxylation routes. This study could be of potential importance in extrapolating the transformation of TC or other antibiotics under the coexistence of heavy metals in water.
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