| 1. |
- Sarmad, Shokat, et al.
(författare)
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Amine functionalized deep eutectic solvent for CO2 capture : Measurements and modeling
- 2020
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Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 309
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Tidskriftsartikel (refereegranskat)abstract
- Deep eutectic solvents (DESs) have gained a great interest among researchers owing to their inherent advantages to become an adaptable alternative to ionic liquids (ILs) and common amine solutions for CO2 capture. In the present study, we prepared five new three-component DESs by functionalization of choline chloride-ethanolamine (1,7, mol,mol) DES using different types of amines: diethanolamine (amine type 2), methyldiethanolamine (amine type 3), piperazine (amine type 2) as well as 1-(2-aminoethyl)piperazine (amine type 1 and 2). All of the prepared DESs are liquid at room temperature and their melting points were in the range of 265–276 K. The solubility of CO2 in the studied DESs was measured at pressures up to 2 MPa and 298.15 K. The obtained experimental data were analyzed by the use of generic Redlich-Kwong equation of state (RK-EOS) model and Henry's law constant have been calculated from the obtained experimental data through the EOS correlation. All the studied DESs show chemical absorption of CO2 which can be approved based on the excess enthalpy and Gibbs energy functions. FT-IR spectroscopy and 13C NMR verified the formation of carbamate in the CO2 absorption process which revealed the chemisorption of CO2 in the studied DESs. The ideal association model has been utilized to describe the excess thermodynamic functions and two different types of the chemical association have been detected AB2 and AB, (A refer to DESs and B to CO2). Based on the obtained solubility data, the amines that enhanced the absorption capacity of choline chloride-ethanolamine (1,7) follow the trend as follows: piperazine > aminoethylpiperazine > methyldiethanolamine > diethanolamine. Therefore, piperazine can be considered as an absorption enhancer. The viscosity of DESs before and after CO2 absorption as well as the thermal behavior of the DESs were also investigated.
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| 2. |
- Sarmad, Shokat, et al.
(författare)
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Vapor-liquid equilibrium of ionic liquids
- 2020
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Ingår i: Encyclopedia of ionic liquids. - Singapore : Springer. - 9789811067396 - 9789813342200 ; , s. 1-22
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Stanicic, Ivana, 1994, et al.
(författare)
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Fate of lead, copper, zinc and antimony during chemical looping gasification of automotive shredder residue
- 2021
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 302
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Tidskriftsartikel (refereegranskat)abstract
- Gasification experiments in this study were performed in a 2–4 MW indirect gasifier coupled to a semi-commercial CFB combustor at Chalmers University of Technology. Experiments were carried out during 13 days with automotive shredder residue (ASR), giving a unique opportunity to investigate the bed material under realistic conditions and with long residence times. The metal rich ash was accumulated in the bed, gaining some oxygen carrying capabilities, creating a chemical looping gasification (CLG) process. This study aims to expand the knowledge about the chemistry of zinc, copper, lead and antimony during CLG of ASR. Several experimental methods have been utilized, such as XRD, SEM-EDX and XPS along with detailed thermodynamic calculations to study chemical transformations that can occur in the system. Thermodynamic calculations showed that the reduction potential affect the phase distribution of these elements, where highly reduction conditions result in heavy metals dissolving in the slag phase. Copper and zinc ferrites, lead silicates and antimony oxides were identified at the particle surfaces in the bottom ash. The formation of an iron rich ash layer plays an important role, especially for copper and zinc speciation. The main pathways in the complex CLG system have been discussed in detail.
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| 4. |
- Ullakko, Kari, et al.
(författare)
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Isothermal Martensite Transformation of Fe-Ni-C Alloys as a Function of Hydrostatic Pressure
- 1990
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Ingår i: Materials Science Forum volumes 56-58. - Zürich : Trans Tech Publiations. ; , s. 197-200
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Konferensbidrag (refereegranskat)abstract
- Isothermal martensite transformation as a function of hydrostatic pressure was studied in Fe-Ni-C alloys. It was observed that the transformation was much the same as it happens as a function of time. Any noticeable differences in the morphology between isothermal and athermal martensite were not seen.
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| 5. |
- Zäll, Erik, et al.
(författare)
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Environmentally sustainable electroplating of selective cobalt-chromium coating on stainless steel for efficient solar collectors
- 2022
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 245
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Tidskriftsartikel (refereegranskat)abstract
- Half of today's global energy consumption is in the form of heating and cooling. Solar collectors are the most promising sustainable alternative to fossil fuels in this sector. The most important component in a solar collector is the receiver, which by use of a selective surface absorbs and converts solar irradiance to thermal energy. Herein, a novel selective surface for low-to mid-temperature solar collectors is developed, studied and presented. The surface is produced by electroplating a cobalt-chromium coating on a stainless steel substrate using an electrolyte based on a deep eutectic solvent. Our method makes use of trivalent instead of traditionally used hexavalent chromium, which significantly reduces health-related issues and makes it more environmentally benign. We obtain a coating of chromium doped cobalt where the surface exhibits an absorptance and emittance of 0.96 and 0.14, respectively, giving it a solar-to-thermal efficiency of 0.95. An observed loss in optical efficiency, is shown to correlate to an oxidation of the metallic cobalt to Co3O4 at elevated temperatures. We further show that this oxidation can be mitigated by dip-coating a protective silica top coating, which concurrently improves the optical selectivity of the surface. The present selective surface is efficient, cheap, scalable, and easy to produce sustainably, making it competitive to industry standards. We foresee that our method will have impact on the advancement of improved low-to mid-temperature solar collectors, assisting a faster transition towards a sustainable society.
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| 6. |
- Buckland, Philip I., 1973-, et al.
(författare)
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The Strategic Environmental Archaeology Database : a resource for international, multiproxy and transdisciplinary studies of environmental and climatic change
- 2015
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Konferensbidrag (refereegranskat)abstract
- Climate and environmental change are global challenges which require global data and infrastructure to investigate. These challenges also require a multi-proxy approach, integrating evidence from Quaternary science and archaeology with information from studies on modern ecology and physical processes among other disciplines. The Strategic Environmental Archaeology Database (SEAD http://www.sead.se) is a Swedish based international research e-infrastructure for storing, managing, analysing and disseminating palaeoenvironmental data from an almost unlimited number of analysis methods. The system currently makes available raw data from over 1500 sites (>5300 datasets) and the analysis of Quaternary fossil insects, plant macrofossils, pollen, geochemistry and sediment physical properties, dendrochronology and wood anatomy, ceramic geochemistry and bones, along with numerous dating methods. This capacity will be expanded in the near future to include isotopes, multi-spectral and archaeo-metalurgical data. SEAD also includes expandable climate and environment calibration datasets, a complete bibliography and extensive metadata and services for linking these data to other resources. All data is available as Open Access through http://qsead.sead.se and downloadable software. SEAD is maintained and managed at the Environmental Archaeology Lab and HUMlab at Umea University, Sweden. Development and data ingestion is progressing in cooperation with The Laboratory for Ceramic Research and the National Laboratory for Wood Anatomy and Dendrochronology at Lund University, Sweden, the Archaeological Research Laboratory, Stockholm University, the Geoarchaeological Laboratory, Swedish National Historical Museums Agency and several international partners and research projects. Current plans include expanding its capacity to serve as a data source for any system and integration with the Swedish National Heritage Board's information systems. SEAD is partnered with the Neotoma palaeoecology database (http://www.neotomadb.org) and a new initiative for building cyberinfrastructure for transdisciplinary research and visualization of the long-term human ecodynamics of the North Atlantic funded by the National Science Foundation (NSF).
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| 7. |
- Bhatti, Tariq M.
(författare)
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Bioleaching of organic carbon rich polymetallic black shale
- 2015
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Ingår i: Hydrometallurgy. - : Elsevier BV. - 0304-386X .- 1879-1158. ; 157, s. 246-255
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Tidskriftsartikel (refereegranskat)abstract
- The present study describes the extraction of metals from organic-carbon rich Kyrk Tasjo (Sweden) polymetallic black shale using mixed cultures of acidophilic iron- and sulfur-oxidizing microorganisms. Quartz, Mite, micro-cline, calcite, dolomite and pyrite minerals were present in shale matrix. Black shale contained 10.77% organic carbon as kerogen and 1.16% inorganic carbon (graphite). The leaching experiments were performed in shake flasks and stirred tank reactors with and without acidophilic Fe- and S-oxidizing psychrotolerant, mesophile and moderate thermophile strains at 6,30 and 45 degrees C. Biological oxidation of pyrite generated sulfuric acid and ferric sulfate in leach solutions during leaching process. Microbial leaching solubilized 80-90% of the total metals (U, Cu, Ni, Mn, Mo, Y and Zn) after 15-20 days of bioleaching at 30 and 45 degrees C; whereas metal solubilization was slower with acidophilic psychrotolerant bacteria at 6 degrees C. The biodegradation of kerogen released tetradecane (CH3(CH2)(12)CH3), a long-chain aliphatic hydrocarbon compound and several other un-identified hydrocarbons in leach solutions during bioleaching of black shale. The addition of PO43- and NH4+ in the growth medium during bioleaching had no effect or decreased the metal solubilization, suggesting that the microorganisms obtained these nutrients from the minerals and kerogen (C100H112O9N2S5), a nitrogenous hydrocarbon compound present in the shale matrix. Metal dissolution from black shale was mainly attributed to the acid concentration in leach solution and temperature. The leaching data demonstrate the feasibility of extracting metals from the black shale without additional nutrient supply that constitute a cost saving for commercial scale application of bioleaching process. The bioleaching approach does not appear warranted to view of the low concentrations, albeit relatively high recoveries of valuable metals from the black shale. The leaching data indicate that exposed black shale occurrences, being subject to ambient weather conditions, constitute a long term environmental challenge.
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| 8. |
- Bjurström, Johan, et al.
(författare)
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Tunable spring balanced magnetic energy harvester for low frequencies and small displacements
- 2022
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 259
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a novel concept to efficiently harvest vibrational energy at low frequencies and very small displacement. We describe and evaluate an electromagnetic energy harvester which generates power from a magnetic circuit with motion induced variations of an air gap. External vibrations induce oscillations of the gap length around an equilibrium point, due to a linear spring counteracting the magnetic force. The relative position of the spring can be adjusted to optimize the harvester output for excitation amplitude and frequency. A simulation model is built in COMSOL and verified by comparison with lab measurements. The simulation model is used to determine the potential performance of the proposed concept under both harmonic and non-harmonic excitation. Under harmonic excitation, we achieve a simulated RMS load power of 26.5 μW at 22 Hz and 0.028 g acceleration amplitude. From a set of comparable EH we achieve the highest theoretical power metric of 1712.2 µW/cm3/g2 while maintaining the largest relative bandwidth of 81.8%. Using measured non-harmonic vibration data, with a mean acceleration of 0.039 g, resulted in a mean power of 52 μW. Moreover, the simplicity and robustness of our design makes it a competitive alternative for use in practical situations.
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| 9. |
- Carlborg, Markus, et al.
(författare)
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Exposure of refractory materials during high-temperature gasification of a woody biomass and peat mixture
- 2018
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 38:2, s. 777-787
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Tidskriftsartikel (refereegranskat)abstract
- Finding resilient refractory materials for slagging gasification systems have the potential to reduce costs and improve the overall plant availability by extending the service life. In this study, different refractory materials were evaluated under slagging gasification conditions. Refractory probes were continuously exposed for up to 27 h in an atmospheric, oxygen blown, entrained flow gasifier fired with a mixture of bark and peat powder. Slag infiltration depth and microstructure were studied using SEM EDS. Crystalline phases were identified with powder XRD. Increased levels of Al, originating from refractory materials, were seen in all slags. The fused cast materials were least affected, even though dissolution and slag penetration could still be observed. Thermodynamic equilibrium calculations were done for mixtures of refractory and slag, from which phase assemblages were predicted and viscosities for the liquid parts were estimated. © 2017 Elsevier Ltd
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| 10. |
- Chernyschova, Irina V., et al.
(författare)
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Mechanism of adsorption of long-chain alkylamines on silicates : a spectroscopic study. 2. Albite
- 2001
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 17:3, s. 775-785
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Tidskriftsartikel (refereegranskat)abstract
- Using FTIR (DRIFTS and IRRAS) and XPS spectroscopy, ζ potential measurements, and Hallimond flotation tests, we confirmed that long-chain primary amines are adsorbed on silicates at pH 6-7 through the 2D-3D precipitation mechanism. The orientation and packing of dodecyl- and hexadecylammonium acetate and chloride adsorbed on albite in the different regions of the adsorption isotherm were determined. It was shown that these characteristics depend strongly on the substrate. Coadsorption of the counterion was not revealed, but the counterion was found to affect indirectly the adsorption at concentrations above the concentration of the bulk amine precipitation
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