Auflistung nach Autor:in "Jekel, Martin"

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A quick test method for predicting the adsorption of organic micropollutants on activated carbon
(2022) Zhang, Qiqi; Jekel, Martin; Ruhl, Aki Sebastian; Zhang, Yongjun
Controlling the contamination of water cycles with organic micropollutants (OMPs) has been targeted in many regions. Adsorption with activated carbon is an effective technology to remove OMPs from different water matrices. To efficiently design or operate the adsorption process, the adsorption of OMPs should be properly assessed, usually with time-consuming batch adsorption tests and sophisticated analyses. In this study, a quick adsorption test method has been developed by loading powdered activated carbon (PAC) into a syringe filter which can be used subsequently to filtrate the water sample in short time (<60 s). Treated wastewater was applied to compare the quick test method and conventional batch test regarding the adsorption of 14 frequently detected OMPs, the abatement of UV254, and changes in fractions of dissolved organic matter (DOM). Similar adsorption patterns of individual OMPs, total OMPs, and DOM fractions was found with two methods. UV254 can predict the removal of total OMPs and most individual OMPs in both methods. Both the abatement of UV254 or the removal of OMPs determined in the quick test led to a highly accurate prediction of OMP adsorption in the conventional adsorption tests. The novel quick test method thus could help operators and researchers quickly monitor the adsorption capacity of PAC products. Quelle: https://www.sciencedirect.com/
Analysis of polyethylene microplastics in environmental samples, using a thermal decomposition method
(2015) Dümichen, Erik; Bannick, Claus Gerhard; Barthel, Anne-Kathrin; Braun, Ulrike; Brand, Kathrin; Jekel, Martin; Senz, Rainer
Small polymer particles with a diameter of less than 5 mm called microplastics find their way into the environment from polymer debris and industrial production. Therefore a method is needed to identify and quantify microplastics in various environmental samples to generate reliable concentration values. Such concentration values, i.e. quantitative results, are necessary for an assessment of microplastic in environmental media. This was achieved by thermal extraction in thermogravimetric analysis (TGA), connected to a solid-phase adsorber. These adsorbers were subsequently analysed by thermal desorption gas chromatography mass spectrometry (TDS-GC-MS). In comparison to other chromatographic methods, like pyrolyse gas chromatography mass spectrometry (Py-GC-MS), the relatively high sample masses in TGA (about 200 times higher than used in Py-GC-MS) analysed here enable the measurement of complex matrices that are not homogenous on a small scale. Through the characteristic decomposition products known for every kind of polymer it is possible to identify and even to quantify polymer particles in various matrices. Polyethylene (PE), one of the most important representatives for microplastics, was chosen as an example for identification and quantification.Quelle: http://www.sciencedirect.com
Anthropogene Spurenstoffe und Krankheitserreger im urbanen Wasserkreislauf
(Universitätsverlag der TU Berlin, 2016) Jekel, Martin; Ruhl, Aki Sebastian
Im Forschungsprojekt ASKURIS wurden das Auftreten und die Entfernung organischer Spurenstoffe und resistenter Krankheitserreger in urbanen Wasserkreisläufen erforscht. Neueste analytische Methoden wurden eingesetzt, um entlang des Wasserkreislaufes bekannte Substanzen in kleinsten Konzentrationen zu quantifizieren und unbekannte Spurenstoffe zu identifizieren. Deren Entfernung durch bestehende und zusätzliche technische Barrieren (Aktivkohle und/oder Ozon) wurde an unterschiedlichen Stellen des Wasserkreislaufes untersucht. Für eine Bewertung der technischen Barrieren wurden Kosten und Auswirkungen auf die Umwelt bilanziert. Toxische Effekte auf Mensch und Umwelt wurden untersucht, um ein eventuelles Risiko abschätzen zu können. Mit empirischen, sozialwissenschaftlichen Methoden wurde die Wahrnehmung von Risiken in der Bevölkerung analysiert. Die Forschungsergebnisse aus ASKURIS wurden in das Risikomanagementsystem des größten deutschen Wasserver- und -entsorgers integriert. Quelle: HP der Hrsg.
Conditioning fixed-bed filters with fine fractions of granulated iron hydroxide (MyGFH)
(2018) Hilbrandt, Inga; Jekel, Martin; Ruhl, Aki Sebastian
The fine fraction of granular ferric hydroxide (MyGFH, < 0.3 mm) is a promising adsorbent for the removal of heavy metals and phosphate, but properties of MyGFH were hitherto not known. The present study aimed at characterizing MyGFH regarding its physical and chemical properties and at evaluating methods for the conditioning of fixed-bed filters in order to develop a process that combines filtration and adsorption. Conditioning was done at different pH levels and for different particle sizes. Anthracite, coke, pumice and sand were studied as potential carrier materials. A method for the evaluation of the homogeneity of the iron hydroxide particle distribution on pumice filter grains using picture analysis was developed. Pre-washed pumice (pH 8.5) proved to lead to high embedment and a homogeneous distribution of MyGFH. Filter runs with phosphate (2 mg/L P) showed similar breakthrough curves for the embedded fine fraction adsorbent and for conventional GFH. © 2018 by the authors.
Impacts of autochthonous particulate organic matter on redox-conditions and elimination of trace organic chemicals in managed aquifer recharge
(2023) Filter, Josefine; Ermisch, Till; Jekel, Martin; Ruhl, Aki Sebastian
Autochthonous carbon fxation by algae and subsequent deposition of particulate organic matter can have signifcant efects on redox conditions and elimination of trace organic chemicals (TOrCs) in managed aquifer recharge (MAR). This study investigated the impacts of diferent algae loadings (0-160 g/m2) and infltration rates (0.06-0.37 m/d) on overall oxygen consumption and elimination of selected TOrCs (diclofenac, formylaminoantipyrine, gabapentin, and sulfamethoxazole) in adapted laboratory sand columns. An infltration rate of 0.37 m/d in conjunction with an algae load of 80 g/m2 (dry weight) sustained oxic conditions in the sand bed and did not afect the degradation of TOrCs. Thus, the availability of easily degradable organic carbon from algae did not infuence the removal of TOrCs at an infuent concentration of 1 Ìg/L. In contrast, a lower infltration rate of 0.20 m/d in combination with a higher algae loading of 160 g/m2 caused anoxic conditions for 30 days and signifcantly impeded the degradation of formylaminoantipyrine, gabapentin, sulfamethoxazole, and diclofenac. Especially the elimination of gabapentin did not fully recover within 130 days after pulsed algae deposition. Hence, measures like micro-sieving or nutrient control are required at bank fltration or soil aquifer treatment sites with low infltration rates. © The Author(s) 2023
Mikroplastik im Wasserkreislauf
(Universitätsverlag der TU Berlin, 2020) Jekel, Martin; Anger, Philipp; Bannick, Claus Gerhard; Barthel, Anne-Kathrin; Grummt, Tamara; Kuckelkorn, Jochen; Obermaier, Nathan; Ruhl, Aki Sebastian; Strobel, Claudia; Technische Universität Berlin. Fachgebiet Wasserreinhaltung; Bundesanstalt für Materialforschung und -prüfung
Das interdisziplinäre Forschungsprojekt MiWa widmete sich grundlegenden Fragestellungen zur Analytik und Wirkung von Mikroplastik-Partikeln im Wasserkreislauf. Es wurden Methoden der Umweltprobennahme, der Probenaufbereitung und verschiedene Detektionsverfahren zur Charakterisierung und Quantifizierung von Mikroplastik intensiv untersucht, miteinander verglichen und weiterentwickelt. Öko- und humantoxikologische Untersuchungen dienten dem Zweck, die potenziell von Mikroplastik ausgehende Gefährdung für die aquatische Umwelt und den Menschen zu analysieren und zu bewerten. Eine Harmonisierung und Standardisierung von Methoden der Probennahme, Probenaufbereitung und Mikroplastik-Detektion sind trotz der erheblichen Fortschritte derzeit nur teilweise möglich. Die ökotoxikologischen Studien zeigen zwar die Aufnahme von Mikroplastik-Partikeln durch einige Organismen, jedoch konnte bisher keine schädigende Wirkung nachgewiesen werden. Dabei wurden für eine Auswahl aquatischer Modellspezies sowohl Szenarien direkter als auch indirekter Exposition innerhalb einer Nahrungskette betrachtet. Interaktionen mit menschlichen Modellzellen wurden bislang nur bei Mikroplastik-Partikeln mit Größen weit unterhalb von 1 Ìm (also Nanoplastik) beobachtet. Eine umfassende Bewertung ist bislang nicht möglich. Quelle: https://depositonce.tu-berlin.de
Mikroplastik: Entwicklung eines Umweltbewertungskonzepts
(2016) Miklos, David; Jekel, Martin; Obermaier, Nathan; Technische Universität Berlin; Deutschland. Umweltbundesamt
In dieser Arbeit wird eine umfassende Literaturzusammenstellung über (potenzielle) Einträge in die Umwelt, sowie Vorkommen und Auswirkungen von MP in der aquatischen Umwelt gegeben. Darüber hinaus werden aktuelle Untersuchungsverfahren von Probenahme, Probenaufbereitung und Analytik betrachtet, kritisch diskutiert und offene Fragen benannt. Ökotestverfahren zur Ermittlung potenzieller MP-Wirkungen werden im Hinblick auf Methodik und Übertragbarkeit überprüft. In diesem Zusammenhang werden insbesondere der limnische Bereich sowie MPEinträge über den Ablauf kommunaler Kläranlagen betrachtet. Hierbei wird ein erster vorläufiger Vorschlag für Beurteilungswerte zu MP in Oberflächengewässern und in Abläufen kommunaler Kläranlagen in Deutschland abgeleitet. Schließlich wird ein Handlungsleitfaden zur Interpretation und Einordnung von Befunden von MP in der Umwelt aufgezeigt, eine mögliche Integration der MP-Thematik in vorhandene Rechtssysteme diskutiert und Vorschläge für Minderungsmaßnahmen werden unterbreitet.Quelle: http://www.umweltbundesamt.de
Optimized and validated settling velocity measurement for small microplastic particles (10-400 My m)
(2023) Dittmar, Stefan; Jekel, Martin; Ruhl, Aki Sebastian
The settling velocity of nonbuoyant microplastics is one of the key parameters to describe their vertical transport in water, yet it has rarely been studied for small microplastics (<500 My m) thus far. Respective measurements are challenging as they are prone to disruptive factors such as thermal convection. With decreasing size, it also becomes more difficult to handle target particles separately. Instead, it is favorable to work with suspensions-especially when characterizing particle populations based on sufficient individual measurements. This study establishes and validates a suitable measuring setup, which mainly consists of a precisely tempered settling column that is monitored via optical imaging with subsequent particle tracking. Comprehensive validation experiments with different spherical particles covering the desired size (10-388 My m) and density range (1.05-2.46 g/cm3) verify exceptionally high measurement accuracy and precision. Different investigation schemes were proposed and successfully tested for polydisperse and monodisperse particle samples, respectively. At elevated particle doses, measured settling velocities increased due to swarm effects and interactions between particles. A novel empirical model was fitted to represent those effects. The model can aid in limiting the particle dosage and thus prevent overestimations of single particle velocities. © 2023 The Authors
Quantification and characterisation of activated carbon in activated sludge by thermogravimetric and evolved gas analyses
(2018) Braun, Ulrike; Dittmann, Daniel; Jekel, Martin; Ruhl, Aki Sebastian
Advanced wastewater treatment with powdered activated carbon (PAC) leads to a spread of PAC into different purification stages of wastewater treatment plants (WWTP) due to recirculation and filter back-wash. Currently, no methods for quantification of PAC in activated sludge are available. In this study, PAC containing activated sludge from four WWTP were examined by two-step thermogravimetric analysis (TGA) with heating up to 600˚C in N2 and subsequently in synthetic air. Direct quantification of PAC according to temperature specific weight losses was possible for one WWTP. Quantification by combining specific mass losses was found to be an alternative direct method, with a detection limit of 1.2% PAC in dry sample mass. Additionally, evolved gas analysis (EGA) by infrared-spectroscopy (FTIR) during TGA revealed interaction mechanisms between PAC and activated sludge. Aliphatic compounds from activated sludge were identified as major substances influenced by PAC. In derivative thermogravimetry (DTG), a typical double peak at approximately 300˚C was found to be related to carbonylic species with increased evolution of acetic acid in aged activated sludge. TGA and EGA are promising tools to understand, control and optimise the application of PAC in advanced wastewater treatment. © 2018 Elsevier Ltd. All rights reserved.