| 1. |
- Dutta, Joydeep, et al.
(författare)
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Device for capacitive deionization of aqueous media and method of manufacturing such a device
- 2019
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Patent (populärvet., debatt m.m.)abstract
- The present disclosure relates to a device 10 for capacitive deionization of an aqueous media containing dissolved ion species. The device comprises a cell comprising a first primary electrode 2 and a second primary electrode 3 arranged opposite the first primary electrode 2 and preferably separated by at least one non-conductive spacer 4, 4'. A third electrode 7 is interposed between the first and the second electrode. The third electrode 7 is grounded whereas the first and the second electrodes are polarized versus the grounded third electrode.
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| 2. |
- Karimiyan, Hanieh, et al.
(författare)
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Graphene Oxide/Polyethylene Glycol-Stick for Thin Film Microextraction of beta-Blockers from Human Oral Fluid by Liquid Chromatography-Tandem Mass Spectrometry
- 2019
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:20
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Tidskriftsartikel (refereegranskat)abstract
- A wooden stick coated with a novel graphene-based nanocomposite (Graphene oxide/polyethylene glycol (GO/PEG)) is introduced and investigated for its efficacy in solid phase microextraction techniques. The GO/PEG-stick was prepared and subsequently applied for the extraction of beta -blockers, acebutolol, and metoprolol in human oral fluid samples, which were subsequently detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). Experimental parameters affecting the extraction protocol including sample pH, extraction time, desorption time, appropriate desorption solvent, and salt addition were optimized. Method validation for the detection from oral fluid samples was performed following FDA (Food and Drug Administration) guidelines on bioanalytical method validation. Calibration curves ranging from 5.0 to 2000 nmol L-1 for acebutolol and 25.0 to 2000 nmol L-1 for metoprolol were used. The values for the coefficient of determination (R-2) were found to be 0.998 and 0.996 (n = 3) for acebutolol and metoprolol, respectively. The recovery of analytes during extraction was 80.0% for acebutolol and 62.0% for metoprolol, respectively. The limit of detections (LODs) were 1.25, 8.00 nmol L-1 for acebutolol and metoprolol and the lower limit of quantifications (LLOQ) were 5.00 nmol L-1 for acebutolol and 25.0 nmol L-1 for metoprolol. Validation experiments conducted with quality control (QC) samples demonstrated method accuracy between 80.0% to 97.0% for acebutolol and from 95.0% to 109.0% for metoprolol. The inter-day precision for QC samples ranged from 3.6% to 12.9% for acebutolol and 9.5% to 11.3% for metoprolol. Additionally, the GO/PEG-stick was demonstrated to be reusable, with the same stick observed to be viable for more than 10 extractions from oral fluid samples.
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| 3. |
- Laxman, Karthik, et al.
(författare)
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Tailoring the pressure drop and fluid distribution of a capacitive deionization device
- 2019
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Ingår i: Desalination. - : ELSEVIER SCIENCE BV. - 0011-9164 .- 1873-4464. ; 449, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- The performance of a capacitive deionization (CDI) device is governed by complex relations between the electrode material properties, fluid velocity and fluid distribution within the device. In order to maximize fluid (water) interaction with the electrodes, the relationships between fluid flow and electrode material properties are explored here to develop novel CDI architectures which reduce the pressure drop, improve surface utilization factor and improve the electrode salt adsorption capacity. Using activated carbon cloth (ACC) as the electrode material, the pressure drop across the CDI device is quantified with respect to flow scheme (flow-between and flow-through CDI modes) used. Computational fluid dynamic (CFD) models are developed to study and optimize the fluid velocity and distribution in order to minimize the device fluid pressure losses. The model predictions are verified by constructing the conceptualized CDI devices and correlating the theoretical and experimentally obtained pressure drops, salt adsorption capacities and fluid flow parameters. The results indicate that up to 60% reduction in pressure drop and similar to 35% increase in specific salt adsorption capacity can be achieved by simple changes to the input-output port architecture of the CDI units. The results describe a method to considerably lower energy consumption in commercial CDI devices.
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| 4. |
- Nordstrand, Johan, et al.
(författare)
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An Easy-to-Use Tool for Modeling the Dynamics of Capacitive Deionization
- 2019
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 123:30, s. 6628-6634
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Tidskriftsartikel (refereegranskat)abstract
- Capacitive deionization is an emerging method of desalinating brackish water that has been presented as an alternative to the widely applied technologies such as reverse osmosis. However, for the technology to find more widespread use, it is important not only to improve its efficiency but also to make its modeling more accessible for researchers. In this work, a program has been developed and provided as an open-source with which a user can simulate the performance of a capacitive deionization system by simply entering the basic experimental conditions. The usefulness of this program was demonstrated by predicting how the effluent concentration in a continuous-mode constant-voltage operation varies with time, as well as how it depends on the flow rate, applied voltage, and inlet ion concentration. Finally, the generality of the program has been demonstrated using data from reports in the literature wherein various electrode materials, cell structures, and operational modes were used. Thus, we conclude that the model, termed the dynamic Langmuir model, could be an effective and simple tool for modeling the dynamics of capacitive deionization.
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| 5. |
- Tofa, Tajkia Syeed, et al.
(författare)
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Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts
- 2019
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Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 9:10
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics are persistent anthropogenic pollutants which have become a global concern owing to their widespread existence and unfamiliar threats to the environment and living organisms. This study demonstrates the degradation of fragmented microplastics particularly low-density polyethylene (LDPE) film in water, through visible light-induced plasmonic photocatalysts comprising of platinum nanoparticles deposited on zinc oxide (ZnO) nanorods (ZnO-Pt). The ZnO-Pt nanocomposite photocatalysts were observed to have better degradation kinetics for a model organic dye (methylene blue) compared to bare ZnO nanorods, attributed to the plasmonic effects leading to better interfacial exciton separation and improved hydroxyl radical activity along with a 78% increase in visible light absorption. These demonstrations of the plasmonically enhanced photocatalyst enabled it to effectively degrade microplastic fragments as confirmed following the changes in carbonyl and vinyl indices in infrared absorption. In addition, visual proof of physical surface damage of the LDPE film establishes the efficacy of using plasmonically enhanced nanocomposite photocatalytic materials to tackle the microplastic menace using just sunlight for a clean and green approach towards mitigation of microplastics in the ecosystem.
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| 6. |
- Tofa, Tajkia Syeed, et al.
(författare)
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Visible light photocatalytic degradation of microplastic residues with zinc oxide nanorods
- 2019
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Ingår i: Environmental Chemistry Letters. - : Springer. - 1610-3653 .- 1610-3661. ; 17:3, s. 1341-1346
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Tidskriftsartikel (refereegranskat)abstract
- Microplastics have recently become a major environmental issue due to their ubiquitous distribution, uncontrolled environmental occurrences, small sizes and long lifetimes. Actual remediation methods include filtration, incineration and advanced oxidation processes such as ozonation, but those methods require high energy or generate unwanted by-products. Here we tested the degradation of fragmented, low-density polyethylene (LDPE) microplastic residues, by visible light-induced heterogeneous photocatalysis activated by zinc oxide nanorods. The reaction was monitored using Fourier-transform infrared spectroscopy, dynamic mechanical analyser and optical imaging. Results show a 30% increase of the carbonyl index of residues, and an increase of brittleness accompanied by a large number of wrinkles, cracks and cavities on the surface. The degree of oxidation was directly proportional to the catalyst surface area. A mechanism for polyethylene degradation is proposed.
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| 7. |
- Yohai, L., et al.
(författare)
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Nanocomposite functionalized membranes based on silica nanoparticles oss-linked to electrospun nanofibrous support for arsenic(v) sorption from contaminated underground water
- 2019
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:15, s. 8280-8289
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Tidskriftsartikel (refereegranskat)abstract
- Nanocomposite functionalized membranes were synthesized using surface functionalized mesoporous silica nanoparticles (MCM-NH2 or MCM-PEI) cross-linked to a modified polyacrylonitrile (mPAN) nanofibrous substrate for the removal of 1 mg L-1 of As(V); a concentration much higher than what has been reported for underground water in Argentina. Adsorption studies were carried out in batch mode at pH 8 with nanoparticles in colloidal form, as well as the nanoparticles supported on the modified PAN membranes (mPAN/MCM-NH2 and mPAN/MCM-PEI). Results indicate a twenty-fold improvement in As(V) adsorption with supported nanoparticles (nanocomposite membranes) as opposed to their colloidal form. The adsorption efficiency could be further enhanced by modifying the nanocomposite membrane surface with Fe3+ (mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+) which resulted in more than 95% arsenic being removed within the first 15 minutes and a specific arsenic adsorption capacity of 4.61 mg g(-1) and 5.89 mg g(-1) for mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+ nanocomposite membranes, respectively. The adsorption characteristics were observed to follow a pseudo-first order behavior. The results suggest that the synthesized materials are excellent for quick and efficient reduction of As(V) concentrations below the WHO guidelines and show promise for future applications.
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