M. Sc. Rebecca Volkmann

PhD Student
M. Sc. Rebecca Volkmann
Building A 71, Room 226
Telegrafenberg
14473 Potsdam

Function and Responsibilities:

PhD student in the Interface Geochemistry section 3.5

GeoGraduate representative GFZ Potsdam

First aid worker Interface Geochemistry section 3.5

Research Interests:

In my PhD project, I will study nucleation and growth kinetics of the phosphate mineral struvite (MgNH4PO4*6H2O). It is common in wastewater pipelines, guano deposits human kidney stones. Recent studies investigated struvite formation conditions especially in wastewaters to avoid pipeline blocking and to recover the precipitates to use them as soil fertilizers. 

I investigate nucleation and growth in a pure system of (NH4)2HPO4 - MgCl2*6H2O with UV-Vis turbidity measurements and monitoring of the pH during struvite synthesis in solution. There is little known about temperature dependence of formation, so I monitor kinetics in a low temperature system. Furthermore, nucleation and growth in solutions with components that are common in urine are conducted to mimick the process of struvite kidney stone formation. This includes co-precipitation and transformation of common paragenetic minerals, such as apatite, brushite and newberyite. Synthesized samples are analysed by scanning electron microscopy (SEM) and X-ray diffraction methods (XRD).

The research also focuses on struvite as a possible phosphorous-providing mineral source for the genesis of early life during the Archean Earth time period. The well-known "warm little pond scenario" for the beginning of life suggests an urea-rich, liquid medium, to that results from struvite formation with urinary components can be transferred. For further information see Struvite crystalization.

Career:

2020 - recent: PhD student, section 3.5, German Research Centre for Geosciences Potsdam

2017 - 2020:    Research assistant, petrology working group, Ruhr University Bochum

2017:                 Student assistant, petrology working group, Ruhr University Bochum

Education:

2017 - 2020:  M.Sc. Geosciences, majoring petrology, Ruhr University Bochum

                          Topic of master's thesis: "Carbonate minerals associated with the volcano-sedimentary iron-ores of the Lahn-Dill type:
                          A petrographic and geochemical study"

2013 - 2017:  B.Sc. Geosciences, Ruhr University Bochum

                          Topic of bachelor's thesis: "Petrographie und Geochemie an Metapeliten der Buchan-Zone in Nordost-Schottland"

Research Boards and Committees:

2021 - recent: Member of the "GetStarted" project group within the German Mineralogical Society to support students and young researchers
                             in the fields of  geochemistry, mineralogy, crystallography and petrology in their professional careers

2017 - recent: Member of the German Mineralogical Society (DMG)

Awards:

2022 | Receiver of bursary for Zurich School of Crystallography 2022

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