| 1521. |
- Posati, Tamara, et al.
(författare)
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Polydopamine Nanoparticle-Coated Polysulfone Porous Granules as Adsorbents for Water Remediation
- 2019
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:3, s. 4839-4847
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Tidskriftsartikel (refereegranskat)abstract
- Water purification technologies possibly based on eco-sustainable, low cost, and multifunctional materials are being intensively pursued to resolve the current water scarcity and pollution. In this scenario, polysulfone hollow porous granules (PS-HPGs) prepared from scraps of the industrial production of polysulfone hollow fiber membranes were recently introduced as adsorbents and filtration materials for water and air treatment. Here, we report the functionalization of PS-HPGs with polydopamine (PD) nanoparticles for the preparation of a new versatile and efficient adsorbent material, namely, PSPD-HPGs. The in situ growth of PD under mild alkaline oxidative polymerization allowed us to stably graft PD on polysulfone granules. Enhanced removal efficiency of ofloxacin, an antibiotic drug, with an improvement up to 70% with respect to the pristine PS-HPGs, and removal of Zn(II) and Ni(II) were also observed after PD modification. Remarkably, removal of Cu(II) ions with an efficiency up to 80% was observed for PSPD-HPGs, whereas no adsorption was found for the PD-free precursor. Collectively, these data show that modification with a biocompatible polymer such as PD provides a simple and valuable tool to enlarge the field of application of polysulfone hollow granules for water remediation from both organic and metal cation contaminants.
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| 1522. |
- Redaa, A., et al.
(författare)
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Assessment of elemental fractionation and matrix effects during in situ Rb-Sr dating of phlogopite by LA-ICP-MS/MS: implications for the accuracy and precision of mineral ages
- 2021
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 36:2, s. 322-344
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Tidskriftsartikel (refereegranskat)abstract
- Laser-ablation inductively-coupled plasma tandem mass-spectrometry (LA-ICP-MS/MS) allows for rapid and interference free analyses of Rb and Sr isotopes, permitting in situ Rb-Sr dating of minerals. However, the general lack of matrix matched reference materials remains one of its main obstacles, affecting both precision and accuracy. This study systematically investigates the impact of matrix effects and down-hole fractionation (DHF) on the in situ Rb-Sr ages of an igneous phlogopite mineral (MDC) analysed by an ICP-MS/MS using two different LA systems: (i) a RESOlution ArF (193 nm) excimer and (ii) a NWR (213 nm) Nd-YAG laser system. A phlogopite reference material (Mica-Mg), originating from the same location as the MDC, was prepared as a pressed nano-powder pellet (NP) and used in this study as a primary reference material. The results revealed that the accuracy of the Rb-Sr ages is typically within about 3% (for 70% of analysed samples), but occasionally higher ranging between 4 to 8% (ca. 30% of cases). We hypothesize that the above bias and uncertainty in the Rb-Sr ages are related to matrix effects between Mica-Mg-NP and MDC, due to their specific ablation characteristics and different physical properties. In addition, the elemental fractionation effects observed in this study for Rb-87/Sr-86 are also dependent on laser wavelength (i.e., 193 nm vs. 213 nm). Hence, developing an improved nano-powder reference material, or a mineral or glass with better matrix matching to natural phlogopite minerals would be desirable to further improve the accuracy of in situ Rb-Sr dating. Currently, regular monitoring of secondary and matrix-matched reference minerals such as the MDC phlogopite can be used to assess and evaluate the accuracy of in situ Rb-Sr dating of phlogopite, yielding ages within accuracy of ca. 3% or better.
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| 1523. |
- Scheiblhofer, E., et al.
(författare)
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Revisiting Glauconite Geochronology: Lessons Learned from In Situ Radiometric Dating of a Glauconite-Rich Cretaceous Shelfal Sequence
- 2022
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Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- The scarcity of well-preserved and directly dateable sedimentary sequences is a major impediment to inferring the Earth's paleo-environmental evolution. The authigenic mineral glauconite can potentially provide absolute stratigraphic ages for sedimentary sequences and constraints on paleo-depositional conditions. This requires improved approaches for measuring and interpreting glauconite formation ages. Here, glauconite from a Cretaceous shelfal sequence (Langenstein, northern Germany) was characterized using petrographical, geochemical (EMP), andmineralogical (XRD) screening methods before in situ Rb-Sr dating via LA-ICP-MS/MS. The obtained glauconite ages (similar to 101 to 97 Ma) partly overlap with the depositional age of the Langenstein sequence (+/- 3 Ma), but without the expected stratigraphic age progression, which we attribute to detrital and diagenetic illitic phase impurities inside the glauconites. Using a novel age deconvolution approach, which combines the new Rb-Sr dataset with published K-Ar ages, we recalculate the glauconite bulk ages to obtain stratigraphically significant 'pure' glauconite ages (similar to 100 to 96 Ma). Thus, our results show that pristine ages can be preserved in mineralogically complex glauconite grains even under burial diagenetic conditions (T < 65 degrees C; <1500 m depth), confirming that glauconite could be a suitable archive for paleo-environmental reconstructions and direct sediment dating.
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| 1524. |
- Shahabi-Ghahfarokhi, Sina, et al.
(författare)
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Background concentrations and extent of Cu, As, Co, and U contamination in Baltic Sea sediments
- 2021
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Ingår i: Journal of Sea Research. - : Elsevier. - 1385-1101 .- 1873-1414. ; 176
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Tidskriftsartikel (refereegranskat)abstract
- This study established background (pre-industrial) values of copper (Cu), arsenic (As), cobalt (Co), and uranium (U) in Baltic Sea sediments. The indicated background values could help identifying the spatial and temporal anthropogenic loads of these elements (metals and metalloids) in the Baltic Sea. In this study, 137 sediment samples were collected from cores obtained from 13 monitoring stations in the Gulf of Bothnia (Bothnian Bay and Sea) and the entire Baltic Proper. To understand the extent of contamination, we used direct and combined methods to define the geochemical background values as inputs for the geochemical index (Igeo) calculation. The obtained values were then compared with the background values established by the Swedish Environmental Protection Agency. From the direct method, Cu, Co, As, and U had background values of 39, 21.5, 12.4, and 6.3 mg kg−1 DW. Copper and U exhibited concentrations above the background values in surface sediment in the western and eastern Baltic Proper (maximum Igeo indicates moderate contamination). Arsenic was above background concentrations in the Baltic Sea and highest in the Gulf of Bothnia (maximum Igeo indicates strong contamination). Cobalt concentrations were within the range of background values (no contamination).
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| 1525. |
- Short, M, et al.
(författare)
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Municipal gravity sewers: an unrecognised source of nitrous oxide
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 468-469, s. 211-218
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Tidskriftsartikel (refereegranskat)abstract
- Nitrous oxide (N 2 O) is a primary ozone-depleting substance and powerful greenhouse gas. N 2 O emissions from secondary-level wastewater treatment processes are relatively well understood as a result of intensive international research effort in recent times, yet little information exists to date on the role of sewers in wastewater management chain N 2 O dynamics. Here we provide the first detailed assessment of N 2 O levels in the untreated influent (i.e. sewer network effluent) of three large Australian metropolitan wastewater treatment plants. Contrary to current international (IPCC) guidance, results show gravity sewers to be a likely source of N 2 O. Results from the monitoring program revealed hydraulic flow rate as a strong driver for N 2 O generation in gravity sewers, with microbial processes (nitrification and possibly denitrification) implicated as the main processes responsible for its production. Results were also used to develop a presumptive emission factor for N 2 O in the context of municipal gravity sewers. Considering the discrepancy with current IPCC Guidelines, further work is warranted to assess the scale and dynamics of N 2 O production in sewers elsewhere. © 2013 Elsevier B.V.
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| 1526. |
- Skoglund, Nils, et al.
(författare)
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Combustion of seaweed - A fuel design strategy
- 2017
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 165, s. 155-161
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Tidskriftsartikel (refereegranskat)abstract
- The high ash content and varying ash composition in algal biomass is often mentioned as problematic if to be used for thermal energy conversion. This paper suggests an approach where detailed information on ash composition and predicted ash formation reactions are basis for successful remedies enabling the use of fuels considered to be difficult. The procedure is demonstrated on seaweed (Saccharina latissima) cultivated for biorefinery purposes. The ash composition of the seaweed was found suitable for co-combustion with Miscanthus x giganteus, an energy crop high in alkali and silicon. Fuel mixtures were combusted in a bubbling fluidized bed reactor and ash samples were analyzed by SEM-EDS and XRD. The results showed that Ca from the seaweed was very reactive and thus efficient in solving the silicate melting problems. The fuel design approach was proven successful and the potential for using otherwise difficult seaweed fuels in synergetic co-combustion was demonstrated. (C) 2017 Elsevier B.V. All rights reserved.
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| 1527. |
- Sädbom, Stefan, et al.
(författare)
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The use of systematic sampling and XRF-XRT based scanning to determine potential recovery of metals from waste rock
- 2020
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Ingår i: Mine Water Solutions. - : International Mine Water Association. - 9783000672972 ; , s. 146-151
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Konferensbidrag (refereegranskat)abstract
- It is difficult to evaluate the potential for reprocessing and extraction of minerals from waste rock with valuable and/or harmful elements.We suggest a new sampling strategy/protocol for waste rock, specifically developed for historic mining sites, in combination with XRF-XRT scanning with a GeoCore X10 instrument.Håkansboda historical mine site in Sweden was used as a case study to look at the potential for the combination of techniques.The combination of the suggested randomized sampling strategy/protocol and the dataset from the GX10 scanning enables prediction of amenability for pre-processing with the use of mechanical sorting or if the extraction of valuable minerals only can be achieved through fine grinding, flotation or leaching.
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| 1528. |
- Tapia-Ruiz, Nuria, et al.
(författare)
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2021 roadmap for sodium-ion batteries
- 2021
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Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 2515-7655. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Increasing concerns regarding the sustainability of lithium sources, due to their limited availability and consequent expected price increase, have raised awareness of the importance of developing alternative energy-storage candidates that can sustain the ever-growing energy demand. Furthermore, limitations on the availability of the transition metals used in the manufacturing of cathode materials, together with questionable mining practices, are driving development towards more sustainable elements. Given the uniformly high abundance and cost-effectiveness of sodium, as well as its very suitable redox potential (close to that of lithium), sodium-ion battery technology offers tremendous potential to be a counterpart to lithium-ion batteries (LIBs) in different application scenarios, such as stationary energy storage and low-cost vehicles. This potential is reflected by the major investments that are being made by industry in a wide variety of markets and in diverse material combinations. Despite the associated advantages of being a drop-in replacement for LIBs, there are remarkable differences in the physicochemical properties between sodium and lithium that give rise to different behaviours, for example, different coordination preferences in compounds, desolvation energies, or solubility of the solid-electrolyte interphase inorganic salt components. This demands a more detailed study of the underlying physical and chemical processes occurring in sodium-ion batteries and allows great scope for groundbreaking advances in the field, from lab-scale to scale-up. This roadmap provides an extensive review by experts in academia and industry of the current state of the art in 2021 and the different research directions and strategies currently underway to improve the performance of sodium-ion batteries. The aim is to provide an opinion with respect to the current challenges and opportunities, from the fundamental properties to the practical applications of this technology.
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| 1529. |
- Tiberg, Charlotta, et al.
(författare)
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Speciation of Cu and Zn in bottom ash from solid waste incineration studied by XAS, XRD, and geochemical modelling
- 2021
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 119, s. 389-398
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Tidskriftsartikel (refereegranskat)abstract
- Millions of tons of bottom ash (BA) is generated from incineration of industrial and municipal solid waste each year within EU. The magnitude of leaching of metals like Cu and Zn is critical for hazard and risk assessment of these ashes. Although speciation of metals is a key factor to understand and predict metal leaching, speciation of Cu and Zn in BA is not well known. In this study six metal separated and carbonized BA were investigated by a combination of X-ray absorption spectroscopy, X-ray diffraction, leaching/extraction tests, and geochemical modelling. Five of the BA were from grate boilers and one from a fluidized bed incinerator. The aims were to identify similarities in Cu and Zn speciation and to identify main species. The combination of several techniques was necessary to draw conclusions about speciation and displayed coherent results. A similar speciation of Cu and Zn was indicated in the five studied grate boiler ashes although the proportions between species may vary. Copper(II) oxide and Cu metal were the main Cu species in all BA. Zinc(II) oxide and willemite (Zn2SiO4) were identified in grate boiler ashes. The fluidized bed ash contained Zn-Si-minerals and possibly franklinite or gahnite, while the Zn(II) oxide content was low, if any. The results have implications for classification and risk assessment of MIBA.
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| 1530. |
- Trublet, Mylene, et al.
(författare)
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Competitive Sorption of Metal Ions on Titanium Phosphate Sorbent(TiP1) in Fixed-Bed Columns : A Closed-Mine Waters Study
- 2019
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:9, s. 8145-8154
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Tidskriftsartikel (refereegranskat)abstract
- Sorptionfixed-bed column experiments were performed using atitanium phosphate ion-exchanger composed of−H2PO4units [TiO(OH)(H2PO4)·H2O]. Model mine water containingfive divalent metal ions (Cu2+,Zn2+,Mn2+,Ni2+,and Co2+) and a few closed-mine water samples were treated to evaluate the sorptionpreference of the material. For thefirst time, dynamic ion-exchange capacities(estimated to be between 3.2 and 4.2 mequiv g−1) and static ion-exchange uptakes(calculated to be between 3.1 and 3.5 mequiv g−1) were obtained for the same TiP1sorbent and data were discussed in terms of sorption behavior. It was found thatsorption processes on TiP1 in model and closed-mine waters during a columnexperiment could be accurately predicted from the corresponding batch experiment(including the sorbent’s capacities in different types of waters). A competitivesorption phenomenon in favor of Cu2+on TiP1 was established for all cases, pointingtoward the possibility of isolating pure copper concentrate from closed-mine waters.The relatively high amounts of calcium and magnesium ions present in mine waters did not appear to considerably affect theselectivity of TiP1 material. Exploratory experiments for sorbent regeneration and desorption using a low concentration of nitricacid were demonstrated.
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