Zimmermann, Yannick
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Yannick
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Zimmermann, Yannick
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- PublikationBiodeterioration affecting efficiency and lifetime of plastic-based photovoltaics(Elsevier, 16.09.2020) Schmidt, Felix; Lenz, Markus; Schaeffer, Andreas; Zimmermann, Yannick; Alves dos Reis Benatto, Gisele; Kolvenbach, Boris; Krebs, Frederik [in: Joule]The low environmental impact of electricity generation using solar cells crucially depends on high energy-conversion efficiencies, long lifetimes and a minimal energy and material demand during production. Emerging thin-film photovoltaics such as perovskites on plastic substrates could hold promise to fulfil all these requirements. Under real-world operating conditions photovoltaic operation is challenged by biological stressors, which have not been incorporated for evaluation in any test. Such stressors cause biodeterioration, which impairs diverse, apparently inert materials such as rock, glass and steel and therefore could significantly affect the function and stability of plastic-based solar cells. Given that different photovoltaic technologies commonly use similar materials, the biodeterioration mechanisms reviewed here may possibly affect the efficiency and lifetimes of several technologies, if they occur sufficiently fast (during the expected lifetime of photovoltaics). Once the physical integrity of uppermost module layers is challenged by biofilm growth microbially mediated dissolution and precipitation reactions of photovoltaic functional materials are very likely to occur. The biodeterioration of substrates and seals also represents emission points for the release of potentially harmful photovoltaic constituents to the environment01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationSystematic approach to harness the potential of CRM secondary sources on the example of red mud(05/2017) Ujaczki, Eva; Zimmermann, Yannick; Gasser, Christoph A.; Molnar, Monika; Feigl, Victoria; Lenz, Markus06 - Präsentation
- PublikationRed mud as secondary source for critical raw materials – Extraction study(Wiley, 2017) Ujaczki, Eva; Zimmermann, Yannick; Molnar, Monika; Feigl, Victoria; Lenz, Markus; Gasser, Christoph A. [in: Journal of Chemical Technology & Biotechnology]Red mud is a by-product of alumina extraction from bauxite by the Bayer process produced in the billion tons scale worldwide. Red muds, or more generally bauxite residues, are regarded as waste, but may potentially be valuable sources of critical raw materials (CRM). In the present study both conventional extracting agents (mineral acids) and small molecular weight complexing agents (organic acids) were evaluated regarding their efficiency to extract CRM such as rare earth elements (REEs) from red mud. On a molar base, highest extraction efficiencies for REEs were achieved using HCl compared with the other acids investigated. Consequently, an experimental design approach was used to determine optimal conditions for CRM extraction using HCl. Instead of maximizing the extraction of a number of selected metals, the maximum economic potential as the sum of all metals (total metal extracted × economic value of the respective metal) was chosen as the application relevant response variable. Four explanatory variables (i.e. HCl concentration, contact time, temperature and slurry concentration) were used. RESULTS Optimal conditions maximizing the economic potential were predicted for 5.98 mol L−1 HCl, 21 h contact time, 50°C, and 56.7 g L−1 slurry concentration. Indeed, experimentally determined economic potential corresponded well (71% of predicted) with the predictions, allowing a maximum recovery of 297.6 US $ t−1. CONCLUSION Though the studied red muds were relatively low in CRM concentrations, the systematic approach developed here allows straightforward transfer to other red muds, harnessing the potential of the latter as important secondary source for CRM. © 2017 Society of Chemical Industry01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationRed mud as secondary source for critical raw materials – Purification of rare earth elements by liquid/liquid extraction(Wiley, 2017) Ujaczki, Eva; Zimmermann, Yannick; Gasser, Christoph; Molnar, Monika; Feigl, Victoria; Lenz, Markus [in: Journal of Chemical Technology & Biotechnology]BACKGROUND Critical raw materials (CRM) are crucial to Europe's economy and essential to maintaining and improving our quality of life due to their usage for production of many devices. Red mud is generated from alumina production where bauxite is digested in hot sodium hydroxide solution during the Bayer process. Red mud can contain considerable amounts of CRM such as rare earth elements (REEs). In the present study, purification of CRM from perturbing, co-extracted elements such as Fe and Al from red mud hydrochloric acid leachates was evaluated. RESULTS A first purification was achieved by removing Fe (>87%) from the acidic leachate using precipitation with NaOH. REEs as well as Al were hardly removed by precipitation (21%, and 33%, resp.). A second purification was achieved using liquid/liquid extraction (LLE) with di-(2-ethylhexyl)phosphoric acid (D2EHPA). Here, four explanatory variables (i.e. LLE organic/aqueous ratio, D2EHPA concentration in kerosene, stripping acid organic/aqueous ratio, HCl concentration) were studied. Finally, the optimal extraction conditions maximizing the economic potential (total metal extracted × economic value of the respective metal) of CRM were determined using a design of experiment approach. CONCLUSION The experimentally determined economic potential extracted corresponded well to the prediction (88%; to the predictions, maximum recovery of 17.18 ± 0.59 US $ t−1). Ultimately, more than 40% of the overall REEs (>62% of the leachable REEs) in red mud were purified using LLE, whereas Al was successfully rejected from the concentrate (∼5% of the overall Al present). © 2017 Society of Chemical Industry01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationEnvironmental aspects of printable and organic electronics (POE)(04/2016) Hengevoss, Dirk; Zimmermann, Yannick; Brun, Nadja; Hugi, Christoph; Corvini, Philippe; Lenz, Markus; Fent, Karl; Nisato, Giovanni; Lupo, Donald; Ganz, Simone [in: Organic and Printed Electronics: Fundamentals and Applications]04 - Beitrag Sammelband oder Konferenzschrift
- PublikationIncineration of organic solar cells: Efficient end of life management by quantitative silver recovery(Royal Society of Chemistry, 2016) Sondergaard, Roar R.; Zimmermann, Yannick; Lenz, Markus; Krebs, Frederik; Martinez Espinosa, Nieves [in: Energy & Environmental Science]Recovery of silver from the electrodes of roll-to-roll processed org. solar cells after incineration has been performed quant. by extn. with nitric acid. This procedure is more than 10 times faster than previous reports and the amt. of acid needed for the extn. is reduced by a factor of 100-150. LCA studies show that the resulting environmental impacts from silver extn. of incinerated ashes are more favorable on almost all std. factors compared to extn. from shredded org. solar cells. The so lessened environmental impacts by efficient recovery fully justify the use of Ag as an electrode in scaled prodn. of org. solar cells.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationOutdoor fate and environmental impact of polymer solar cells through leaching and emission to rainwater and soil(Royal Society of Chemistry, 2016) Martinez Espinosa, Nieves; Zimmermann, Yannick; dos Reis Benatto, Gisele A.; Lenz, Markus; Krebs, Frederik [in: Energy & Environmental Science]The emission of silver and zinc to the aq. environment (rain, fog, dew) from polymer solar cells installed outdoors is presented. Studies included pristine solar cells and solar cells subjected to mech. damage under natural weather conditions in Denmark. We find the emission of silver and zinc to the environment through pptd. water for damaged solar cells, and also obsd. failure and emission from an initially undamaged device in an expt. that endured for 6 mo. In the case of the damaged cells, we found that the drinking water limits for Ag were only exceeded on a few single days. We also progressed our studies to include end-of-life management. To assess the implications of improper practices (uncontrolled disposal, landfilling) at the end-of-life, we buried different OPV types in intact and damaged forms in soil columns. In the case of high Ag emission (shredded cells), the potential for migration was confirmed, even though the soil was found to exhibit sequestration of silver. We conclude that recycling of Ag at the end-of-life is mandatory from an environmental point of view.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationFeasibility for critical raw material recovery from Hungarian red muds of different origin(2015) Ujaczki, Eva; Zimmermann, Yannick; Feigl, Victoria; Lenz, Markus06 - Präsentation
- PublikationRecovery of rare earth elements from Hungarian red mud with combined acid leaching and liqiud-liquid extraction(2015) Lenz, Markus; Ujaczki, Eva; Zimmermann, Yannick; Feigl, Victoria [in: Bauxite Residue Valorisation and Best Practices Conference]04 - Beitrag Sammelband oder Konferenzschrift
- PublikationEvaluation of two Reuse Technologies for a Hungarian Red Mud(2015) Lenz, Markus; Ujaczki, Eva; Zimmermann, Yannick; Molnar, Monika; Gruiz, Katalin; Feigl, Victoria06 - Präsentation