Practical trainings, student assistants and theses

Lithium is in high global demand due to its suitability for a wide range of applications, particularly in rechargeable batteries for the electronics sector. This is attributed to its low mass and high energy density, which enable compact battery designs and efficient recharging capabilities of lithium-ion accumulators. In the battery electric vehicle (BEV) sector, lithium is particularly difficult to replace. Between 2010 and 2100, an estimated increase of 20 million metric tons (Mt) is expected in this field, representing a remarkable 21% rise from the 107,000 tons produced just one year earlier. This trend might be ascribed to the increasing development and demand for lithium-ion batteries in the electric vehicle sector. Currently, lithium is mined from brines, pegmatites, or sedimentary rocks. However, its limited supply, coupled with significant environmental and political challenges associated with traditional production methods, necessitates the development of alternative technologies for lithium recovery. One promising approach is the recovery of lithium from spent batteries or battery waste. This method not only helps address the global supply-demand gap but also conserves natural resources and reduces environmental impact by minimizing the need for new mining activities. Furthermore, recycling lithium from used batteries supports the creation of a circular economy, ensuring a sustainable and resilient supply chain for this critical material. However, the development of a highly lithium-selective and cost-effective materials is still challenging due to its chemical properties. The analogues of organic ligands such as crown ethers and calix[n]arens are found to be most effective for the lithium recovery due to their distinctive features, including ring size and functional attaching groups. The objective of this thesis is to design and develop various crown ethers and calix[n]arenes for the selective recovery of lithium from different battery waste solutions. The developed crown ethers and calix[n]arenes will be tested for complexation with lithium ions using various analytical techniques followed by its application in bioionflotation and liquid-liquid extraction.
Key Responsibilities:

• Conduct literature research on crown ethers and calix[n]arenes for the recovery of lithium through hydro- and biometallurgical process
• Design and conduct laboratory experiments using synthesized crown ethers and calix[n]arenes with different hydrometallurgical and biometallurgical parameters
• Optimize experimental conditions for high recovery rates for lithium and other valuable metals
• Prepare a thesis report and present findings at conferences or workshops

• Bachelor's degree in Chemistry, Chemical Engineering, Biotechnology, Environmental Engineering or related field
• Good oral and written communication skills in English or German
• Ability to work independently and systematically

• Duration: 6 months
• Start Date: Start in April 2025 is possible
• Funding: Remuneration according to HZDR internal regulations

This study examines how surface properties (particle size, porosity, surface area, ...) affect the carbonation of Ca/Mg silicate minerals or tailings, focusing on enhancing CO₂ sequestration and understanding chemical mechanisms. Advanced techniques, including BET, porosimetry, SEM imaging, particle size distribution (PSD) analysis, XRD, Raman spectroscopy, XRF, TGA, and particle shape/geometry studies will be used. A modified regrind mill setup will optimize surface area under ambient conditions to minimize passive layer formation and improve carbonation kinetics. The findings aim to support sustainable cement production by enhancing CO₂ sequestration processes and adding value to mine tailings.

• Educational background: Chemcial or Materials engineering, Process engineering or related field
• Knowledge of basic laboratory skills, analytical techniques (such as Raman spectroscopy, TGA, ICP, XRF, )
• Good English skills
• Ability to work independently

• Duration: 6 months
• Start date: as soon as possible
• Workplace: Freiberg

Emerging pollutants, such as pharmaceuticals and per- and polyfluoroalkyl substances (PFAS), pose significant environmental and health risks due to their persistence and bioaccumulation. Conventional treatment methods often fail to effectively remove these contaminants from water systems. This master’s thesis focuses on an advanced hybrid approach combining bioflotation with hydrodynamic cavitation (HC) to enhance pollutant removal efficiency. The study aims to evaluate the effectiveness of this method in degrading or separating pharmaceuticals and PFAS from contaminated water and optimizing process parameters.
Tasks:

• Selection of suitable bioflotation agents and hydrodynamic cavitation parameters for pollutant removal
• Characterization of treated water samples using analytical techniques such as HPLC and TOC analyser
• Optimization of bioflotation and cavitation conditions to enhance removal efficiency

• Field of study: Chemistry, Chemical Engineering or related field
• Experience in organic chemistry, knowledge of the techniques to synthesize compounds and to characterize them; experience in coordination chemistry, biochemistry and/or technical chemistry is advantageous
• Good oral and written communication skills in English or German
• Ability to work independently and systematically

• Working in a multi-disciplinary team
• Working place HZDR: Location Dresden and Freiberg (HIF)
• Start date: Either an immediate start or a start in Spring 2025 is possible
• Duration of the internship or thesis according to the study regulations, but at least 4 months
• Remuneration according to HZDR internal regulations, scholarship holders (e.g., ERASMUS+) are welcome

As an important element in batteries, lithium is a critical material for the future energy transition. Derivatives of the alkaloid punicine have been developed with various organic residues to specifically interact with elements such as lithium, or lithium-containing minerals, as surfactants for the upgrading of battery recycling products via flotation separation. Punicine, as a head group, represents a zwitterionic, switchable biomolecule (biosurfactant), in terms of charge via pH and in terms of radical state via UV irradiation potentially influencing its specific interaction with chemical groups or ions. This could be an important factor in ion flotation, which is used to separate ions from battery wastewater. The aim of the project is to investigate this aspect, with a focus on the specific interactions of punicine with lithium ions under the influence of irradiation. Along with ion flotation as the separation method, fundamental investigations such as calorimetry and FTIR will be employed.
We are looking for a motivated student who enjoys working with analytical methods and is eager to explore complex interrelationships.

• Student in, for example, Chemistry, Chemical Engineering, Process Engineering, etc.
• Interest in analytical methods
• First experience in the lab and working with analytical methods (FTIR, Calorimetry, etc.)

• Start date from April 2025 onwards
• Duration of the internship or thesis according to the study regulations, but at least 4 months
• Compensation possible, scholarship holders (e.g., ERASMUS+) are welcome

Currently, there is a broad discussion whether ventilation by frequent window opening is sufficient for providing a sufficient amount of fresh air or if technical air purification devices based on e.g. HEPA filters are better solutions for public spaces. Furthermore, there is another discussion ongoing, whether a well-guided laminar flow or a high degree of mixing within a room is more beneficial. The latter, on the one hand distributes the potentially virus-laden aerosols in the whole room, but on the other hand reduces the peak concentrations of these aerosols clouds by magnitudes.

The objective is to perform aerosol propagation experiments and to estimate the potential aerosol inhalation of people in dynamic situations. To achieve this, an aerosol generator will be used in a demonstrator room under different flow conditions. The data from different scenarios will be processed in order to obtain a transference function that can relate the aerosol source with the aerosol receivers.

X-ray fluorescence analysis (XRF) is a standard method to analyse a wide range of elements. Unfortunately, light elements (Z<11) are hard or impossible to analyse using XRF. On the other hand, LIBS (Laser induced breakdown spectroscopy) is able to analyse these elements. Especially the analysis of Lithium in solid samples is an urgent and currently needed topic. We aim to combine the two methods by developing an integrated workflow using fused beads, which is a standard technique for XRF sample preparation, for XRF analysis of the major elements and subsequent LIBS analysis for elements like e.g. Li.
Besides the development of a simple procedure to produce fused beads appropriate for both methods, calibration for both XRF and LIBS have to be implemented. The outcome of this (Master’s, Bachelor’s) thesis should be a as simple as possible workflow (including sample preparation), a sufficient number of reference materials (by e.g. mixing pure components), calibrations for XRF and LIBS, respectively and an evaluation of the desired method’s limitations. Motivated students of analytical chemistry, geosciences or adequate subjects are addressed.

Fine-grained solid particles from various industrial sources, which would otherwise be discarded, should ideally be processed to valuable products or inert residues. They contain valuable residuals, such as metals, that can be returned to the industrial cycle instead of being landfilled. This is one aim of the Helmholtz project FINEST in which this work is embedded.
The different finest powders need to be mixed and agglomerated for further processing. Our work in the project deals with the granular mixing. One aim is to describe the process using flow simulations in OpenFOAM.
The particle flow is described based on the rheology of the bulk material, while the mixing process between the particles is described using a transport equation. In addition, there are terms for the segregation that takes place in parallel.
We are looking for someone with experience in CFD or other modelling to refine the implementation of this model and then perform parameter studies and validation using experimental data.

• Student of e.g. Computational Engineering, Modelling and Simulation, Mechanical Engineering, Process Engineering, Chemical Engineering
• General interest in fluid mechanics and simulations
• Preliminary experience in CFD, ideally OpenFOAM
• Preliminary experience in code development (C++) optional

• Start from March 2025
• Duration of internship or thesis according to study regulations
• Remuneration available, scholarship holders (e.g. ERASMUS+) welcome

Focused ion beam induced deposition (FIBID) allows the high resolution 3D printing of insulating, conducting, semiconducting and superconducting nanostructures with nearly arbitrary shape. However, while being similar to focused electron beam induced deposition (FEBID) the physical processes are different enough that successful printing strategies from FEBID can not be transferred one to one to the FIBID process. FEBID 3D Algorithm for Stream File generation (F3AST) is a software package developed by our partners at the Vienna University of Technology (TU Wien) that has been successfully used to predict growth parameters for FEBID. The package is agnostic to the underlying charged particle technique and should be capable—potentially with some minor modifications—to also be used for the FIBID process.

The objective of this master thesis is to obtain calibration parameters for FIBID using the helium ion microscope (HIM). The HIM is a focused ion beam (FIB) technique that allows the imaging and fabrication of nanostructures with an optimum resolution in the sub-nanometer range. It utilizes a 0.5 nm wide focused beam of He ions to raster scan the surface. This beam of energetic (typically 10 keV to 30 keV) ions can be used for high resolution imaging and materials processing. After successful calibration of the model complex 3D nanostructures will be created to demonstrate the applicability of the
F3AST software for ion beam based 3D printing.

The researchers at the TU Wien will provide a modified version of the F3AST code able to generate input files for the FIBICS NPVE pattern generator. HIM and a W(CO)6 precursor gas will be used to grow simple 3D structures for the calibration of the software. HIM and scanning electron microscope (SEM) imaging will be used to obtain high resolution images of the nanostructures and extract the required geometrical parameters which will be feed to the F3AST software. Transmission electron microscope (TEM) investigations will be used to assess the composition of selected structures.
After successful completion of the calibration complex 3D structures will be grown and their fidelity will be qualitatively and where possible quantitatively evaluated.

Bachelor in Physics or Materials Science
Ability to work in a nanotechnology lab using delicate equipment
Ability to create simple scripts using python or similar languages
Presentation and office skills

You will be embedded in the ion induced nanostructures group (FWIZ-N) at the ion beam center (IBC) of the HZDR.

Understanding the behaviour of fibre-laden drops is critical due to their presence in various industrial applications, including microelectronics fabrication, portable medical devices, and biofuel production. Our work focuses on the numerical simulation of fibre-laden drops, specifically investigating a single long deformable fibre within a drop impacting a solid substrate. The study aims to elucidate the dynamic interactions between the fibre and the drop. Key objectives include determining the changes in drop dynamics due to the fibre and observing fibre deformation upon impact.

This work will involve computational fluid dynamics (CFD), particularly finite volume methods, with a focus on interface tracking using the Volume of Fluid approach. The simulation will incorporate surface wettability to enhance our understanding of elasto-capillary interactions, offering insights relevant to real-world applications.

We are seeking a motivated student with prior experience in CFD (preferably OpenFOAM) or similar modelling software.

• Enrolled in a degree program such as Process Engineering, Mechanical Engineering, or Computational Modelling and Simulation
• Strong interest in particle-fluid dynamics and numerical simulations
• Preliminary experience in CFD, ideally with OpenFOAM
• Basic coding skills, preferably in C++

• Immediate start possible
• Duration of internship or thesis as per university regulations
• Remuneration available, scholarship holders (e.g. ERASMUS+) are welcome

Production of electricity by nuclear power plants inevitably generates high-level and long-lived radioactive waste. A solution considered by several nuclear waste management agencies is to store them into deep underground repositories. The principle of such a concept is to provide a multi-barrier system to avoid the release of the radioactive waste through the biosphere for very long time scales (up to hundred thousand of years). It is thus of great importance to be able to characterize both at a macroscopic and a molecular level the different processes (retention, reduction, surface precipitation, etc.) that can take place onto mineral surfaces and thus affect the availability and the mobility of the radionuclides. This information can be inserted in surface complexation models for the description and prediction over a long time-scale of the interaction of pollutants at the solid/liquid interface with several sorbent surfaces. These surface complexation models rely on a thermodynamic description of the solid/water interface and represent a geochemically robust and sound approach to quantify adsorption equilibria.

The solution of adsorption equilibria problems can be reached via Gibbs Free Energy Minimization and/or Law of Mass Action. Standard procedures apply commonly used geochemical software such as FITEQL/PHREEQC coupled to shell optimizers (UCODE, PEST). They are nevertheless subject to numerical instability and/or convergence problems, and to the risk to fall into a local minimum region rather than a global optimum valley. This risk is drastically increased when the number of adjustable parameters becomes higher than 3 or 4. Also the “trial and error” approach within the numerical fitting data can become very fast time consuming.

Thus, the objective of the present work are i) to develop alternative approaches to enable the handling of a high number of adjustable parameters at once, ii) the speed up of the optimizing procedure in order to reduce the time required for the user to reach a satisfactory description of the experimental data.

Your specific tasks:

• Implement a genetic algorithm coupled to Levenberg-Marquardt optimization on a high performance computing cluster,

• Compare the results of with another optimization path, namely Downhill Simplex,

• Find reliable ways to provide realistic uncertainties of the adjustable parameters (e.g. scale sensitivity, Monte-Carlo, etc.).

This internship or assistant position can be used as a basis for a follow-up Research Project, Bachelor or Master thesis.

Good knowledge in python programming and standard optimization routines (Newton-Raphson, Levenberg-Marquardt, etc.) is mandatory.

Students without knowledge in chemistry are also encouraged to apply.

Very good English skills are appreciated.

Duration min. 3 months

Start: from now

Workplace: HZDR, Dresden-Rossendorf

At Helmholtz-Zentrum Dresden-Rossendorf (HZDR), over 1,500 employees from more than 70 nations are conducting cutting-edge research in the fields of ENERGY, HEALTH, and MATERIALS to address the major challenges facing society today.
The Center for Advanced Systems Understanding (CASUS), founded in Görlitz in 2019, is a German-Polish interdisciplinary research center focusing on data-intensive digital systems.
CASUS offers student internships in a wide range of scientific fields. You are welcome to apply and join CASUS if you are interested in gaining knowledge in the following research areas:

• Theoretical Chemistry
• Earth System Science
• Systems Biology
• Digital Health
• Computational Radiation Physics
• Theory of complex systems
• Dynamics of Complex Living Systems
• Machine Learning for Infection and Disease

• Student in computer science, physics, chemistry, or related fields
• Student already enrolled at the university in Germany, Poland or Czech Republic (close exchange and attendance in the office preferable and combined with the moblie working from Germany combinable)
• Eager to learn new skills
• Strong motivation to work in a collaborative environment
• Preliminary experience in code development is an advantage
• Excellent communication skills in English and/or German or Polish

• A vibrant research community in an open, diverse and international work environment
• Scientific excellence and extensive professional networking opportunities
• A wide range of qualification opportunities
• We support a good work-life balance with the possibility of part-time employment, mobile working and flexible working hours
• Either an immediate start or a start in 2024 is possible

1D- und 2D-Ramanspektroskopische Meßreihen oder auch Maps liefern detaillierte ortsaufgelöste chemische Informationen über die untersuchten Proben. Damit kann z. B. die Komponentenverteilung in Stoffgemischen quantitativ bestimmt oder die Homogenität einphasiger Proben gezeigt werden. Andererseits lassen sich lokale Strukturveränderungen, Spannungszustände, Stapelfolgenänderungen in 2D-Materialien und Punktdefekte charakterisieren. Voraussetzung dabei ist eine möglichst engmaschige Datenerfassung bis hin zur Auflösungsgrenze der verwendeten Laserstrahlung sowie eine große Anzahl an Messpunkten. Mit modernen Spektrometern sind Messzeiten im Sekundenbereich gut realisierbar. Die Umsetzung der spektroskopischen in eine chemische Information erfordert dann die Extraktion von Parametern wie Schwingungsfrequenz, Intensität und Linienbreite durch Spektrenanpassung. Die Gerätesoftware bietet dafür nur eingeschränkte Möglichkeiten.
Im Rahmen einer Graduierungsarbeit soll in Zusammenarbeit mit dem HZDR-Rechenzentrum ein Auswertealgorithmus für die automatisierte Auswertung von 1D- und 2D-Ramanspektroskopischen Meßreihen entwickelt, an Beispielen getestet und dokumentiert werden.

1. Studium der Werkstoffwissenschaften, Physik oder Chemie
2. Interesse, Freude und Befähigung für wissenschaftliche Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Sehr gute Englisch-Kenntnisse

Die Arbeit ist in die umfangreichen Aktivitäten der Abteilung Nanoelektronik (FWIO) zu 2D-Werkstoffen eingebettet. Sie kann jederzeit aufgenommen werden.

Background:

Currently, there is a broad discussion whether ventilation by frequent window opening is sufficient for providing a sufficient amount of fresh air or if technical air purification devices based on e.g. HEPA filters are better solutions for public spaces. Furthermore, there is another discussion ongoing, whether a well-guided laminar flow or a high degree of mixing within a room is more beneficial. The latter, on the one hand distributes the potentially virus-laden aerosols in the whole room, but on the other hand reduces the peak concentrations of these aerosols clouds by magnitudes.

Objectives:

The objective is to perform aerosol propagation experiments and to estimate the potential aerosol inhalation of people in dynamic situations. To achieve this, an aerosol generator will be used in a demonstrator room under different flow conditions. The data from different scenarios will be processed in order to obtain a transference function that can relate the aerosol source with the aerosol receivers.

Tasks:

• Literature survey
• Aerosol experiments in different scenarios.
• Post-processing of the results.

• Student of natural sciences or engineering
• Willingness to conduct experimental work

Duration:

4-6 months

Remuneration:

According to HDZR guidelines

Wir beschäftigen uns mit der Entwicklung von PET-Radiotracern, die Rezeptoren im Tumormikromilieu (TME = tumor microenvironment) für die Diagnostik und Therapie von Krebs sichtbar machen. Dazu werden geeignete tumoraffine Leitstrukturen identifiziert (niedermolekulare organische Moleküle, Peptide und Peptidomimetika), synthetisiert und mit einem geeigneten Radionuklid kovalent (z. B. Fluor-18, Iod-123) oder über einen Chelator (z. B. Gallium-68, Lutetium-177) markiert. Diese Radioliganden werden in vitro an Tumorzelllinien und in vivo im Tiermodell hinsichtlich einer Anwendung in der Nuklearmedizin getestet. Langfristiges Ziel ist die Translation der entwickelten Radiotracer in die Klinik als Diagnosewerkzeug (PET/CT) oder nach Markierung mit einem Beta- oder Alphastrahler für die Endoradiotherapie von Tumorerkrankungen.
Im Rahmen eines Studentenpraktikums oder einer Bachelor- oder Masterarbeit sollen organische Wirkstoffmoleküle synthetisiert und für eine anschließende radiochemische Markierung modifiziert werden. Die neuen Radioliganden werden dann biologisch in vitro und in vivo untersucht.

• Studium der Chemie
• Gute Noten in organischer Synthesechemie
• Fähigkeit sich in ein interdisziplinäres Wissenschaftler-Team einzugliedern
• Bereitschaft zum Umgang mit Radioaktivität
• Gute Kenntnisse der deutschen und englischen Sprache

• Beginn nach Absprache jederzeit möglich
• Praktikumsdauer mind. 4 Wochen, mit möglichst täglicher Anwesenheit

Turmkraftwerke stellen die neueste Generation von Anlagen zur solarthermischen Elektroenergieerzeugung dar (s. Abbildung). Großflächige Spiegelanordnungen konzentrieren Sonnenlicht auf einen zentralen Absorber, wo es in Wärmeenergie umwandelt wird, die dann auf ein Wärmeträgermedium übertragen wird. Gegenüber der Photovoltaik hat die Solarthermie den inhärenten Vorteil, Energie zu speichern und bei Bedarf bereit zu stellen. Die Herausforderung für die weitere Erhöhung des Wirkungsgrades von Solarkraftwerken besteht in der Entwicklung von Werkstoffen mit einer Temperaturstabilität bis zu 800 °C an Luft.
Im Rahmen von Graduierungsarbeiten und Hilfstätigkeiten sollen thermisch stabile Beschichtungen für die Kernkomponenten von Solarturmkraftwerken entwickelt und getestet werden. Dabei kommen modernste in situ und ex situ Methoden wie Magnetronsputtern, Ellipsometrie, UV-vis-NIR-FTIR-Reflektometrie und Ramanspektroskopie zur Anwendung.
Zu diesem Themenbereich werden u. a. die folgenden Aufgabenstellungen angeboten:
i) Schichtabscheidung und Optimierung der optischen und elektrischen Eigenschaften von transparenten leitfähigen Oxiden für Solarkraftwerke;
ii) Entwicklung von neuartigen Absorber- und Wärmespeicherwerkstoffen für Solarkraftwerke;
iii) Design und Simulation von solarselektiven Beschichtungen für Solarkraftwerke.

Zur Charakterisierung der untersuchten Materialien stehen modernste in situ und ex situ Analysemethoden zur Verfügung. Die Arbeiten können jederzeit aufgenommen werden.

1. Studium der Werkstoffwissenschaften, Physik oder Chemie
2. Interesse, Freude und Befähigung für experimentelle wissenschaftliche Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Sichere Englischsprachkenntnisse (fließend oder besser)

Internationale Forschungsumgebung, ortsübliche Aufwandsentschädigung