Dr. Milad Eftekhari Tel.: +49 351 260 3873

Job-Id: 2026/35 (2208)

At HZDR, we promote and value diversity among our employees. We welcome applications from people with diverse backgrounds regardless of gender, ethnic and social origin, belief, disability, age, and sexual orientation. Severely disabled persons are given preference in the event of equal suitability.

Helmholtz-Zentrum

01328 Dresden

PhD Student (f/m/d) Experimental analyses of Ion-Specific effects on Bubble-Particle Attachment and Bubble-Bubble Coalescence in Flotation

With cutting-edge research in the fields of ENERGY, HEALTH and MATTER, around 1,500 employees from more than 70 nations at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) are committed to mastering the great challenges facing society today.

The Institute of Fluid Dynamics is conducting basic and applied research in the fields of thermo-fluid dynamics and magnetohydrodynamics in order to improve the sustainability, the energy efficiency and the safety of industrial processes.

The Department of Fluid Dynamics Resource Technology Processes is looking for a PhD Student (f/m/d) Experimental analyses of Ion-Specific effects on Bubble-Particle Attachment and Bubble-Bubble Coalescence in Flotation.

Your tasks

• Measure ion-specific effects on bubble-particle attachment and detachment using an innovative flotation kinetics apparatus
• Study particles from industrial partners to map attachment and detachment kinetics as functions of water composition, reagents, dosages, and their interactions
• Quantify ion-specific effects on bubble coalescence using innovative multicolour thin-film interferometry
• Evaluate synergistic effects between ions in recycled water and added frothing agents, and determine film lifetimes for model development
• Use an inline endoscope and an optical fiber Doppler probe (OFDP) to determine bubble surface loading as well as bubble size and velocity
• Integrate and interpret measurement data to derive robust relationships between water chemistry, reagents, and interfacial flotation mechanisms
• Support model development and model parameterization (e.g., attachment/detachment kinetics, coalescence models) based on experimental data
• Document, present, and publish results in reports, scientific contributions, and project meetings

Your profile

• Completed university studies (Master/Diploma) in the field of Process Engineering, Chemical Engineering, Chemistry (especially Physical Chemistry / Surface Chemistry), Physics, Mechanical Engineering, Materials Science, or a comparable discipline
• Experience in or strong interest in interfacial physics/chemistry, surface science, wetting, thin films, and colloidal/interfacial phenomena
• Experience in or strong interest in bubble-particle interactions, especially attachment/detachment and flotation kinetics
• Basic familiarity with multiphase measurement systems (e.g., optical probes, inline endoscopy, interferometric methods) is an advantage
• Interest in model development and model parameterization based on experimental data (e.g., kinetic models, coalescence models) is desirable
• Independent, structured, and reliable way of working in the laboratory
• Strong problem-solving skills in experimental setup, instrumentation, and measurement campaigns
• Good teamwork and communication skills in an interdisciplinary project environment
• Willingness to collaborate with industrial and academic partners and to participate in experimental campaigns; a secondment of around 3 months in Cape Town, South Africa is planned
• Good programming skills for data analysis, image processing, and model fitting (e.g., Python, MATLAB)
• Good written and spoken English

Our offer

• A vibrant research community in an open, diverse and international work environment
• Scientific excellence and extensive professional networking opportunities
• A structured PhD program with a comprehensive range of continuing education and networking opportunities - more information about the PhD program at the HZDR can be found here
• Salary and social benefits in accordance with the collective agreement for the public sector ( TVöD-B und) including 30 days of paid holiday leave, company pension scheme (VBL)
• We support a good work-life balance with the possibility of part-time employment, mobile working and flexible working hours
• Numerous company health management offerings
• Employee discounts with well-known providers via the platform Corporate Benefits
• An employer subsidy for the "Deutschland-Ticket Jobticket"

We look forward to receiving your application documents (including cover letter, CV, diplomas/transcripts, etc.), which you can submit via our online-application-system.