Nelson Mandela University - Port Elizabeth, South Africa
Topic of the exchange program: Lysis of algae (especially diatoms) in ionic liquids, extraction of silica shells and educts for green biodiesel synthesis.
As part of the newly established exchange program between the Nelson Mandela University (NMMU) in Port Elisabeth and the Johannes Gutenberg-Universty (JGU) in Mainz, Julian Schülein visited the group of Prof. Dr. B. Zeelie at InnoVenton.
Combining the knowledge of functional ionic liquid synthesis at JGU and algae lipofaction at NMMU, the task was to extract diatom-algae without disrupting the silica shell. Furthermore, the extraction products should be used in green biodiesel processing.
The most promising group of ionic liquids for the lipofaction of the very tough cellulose based membranes were the imidazolium acetates, which unfortunately are very complicated to synthesize using common batch routes. However, a process to manufacture heavy metal free dimethylimidazolium acetate was established at JGU so that the lipofaction could be investigated with this group of ionic liquids. The absence of heavy metals is crucial for bio-applications to exclude metal-induced toxicity as reason for the death of algae.
The experiments showed the consistency and feasibility of lysis using acetate ionic liquids. GC-MS analysis showed that a high fraction of lysis byproducts were the desired n-alkane alkohols, which could be easily converted to biodiesel. Usually disrupting algae shells to yield n-alkane alkohols is done at very high temperatures and pressure which could be avoided using the ionic liquid catalyzed process at ambient pressure and temperature.
Julian Schülein was awarded the Hoechst scholarship for scientific offspring during his stay abroad.
Left: Julian Schülein at Innoventon Labs, right: graphical abstract of the project
Zhejiang University - Hangzhou, P.R. China
Topic of the exchange program: Development of a fully automated micro phase separator using common electronics
The Chinese Academy of Science awarded Viktor Misuk and Julian Schülein with a full scholarship for up to 3 months to visit the group of Prof. Dr. J. Lu at the Chemical Science and Engineering Departement in Hangzhou, P.R. China. The goal of this program was to design a fully automated phase separator for microfluidic applications.
The main challenge of this project was to create an interface between an commercially available phase separator from Microglas and a custom designed flow control unit using common electronic hardware.
Depending on the viscosity and flow rate of the two-phase medium, the available phase separator was not functioning efficiently without permanent regulation by hand. This was, however, inefficient, not reliable and not feasible for 24/7 operation of industrial plants.
The problem was solved by using a commercially available webcam and a self-programmed image analysis software. The software recognized the phase boundary as well as the chip boundaries and was capable of adjusting the self-assembled and automated outlet valves so that the phase boundary was kept in the middle of the separator.
Further use of this image analysis software was to recognize and characterize the mixing quality in retention mixing units (RMU, more) in glass capillaries.
Left: Part of the Prof. Dr. Lu's research group with Viktor fine tuning the automated valves, right: Viktor Misuk, Julian Schülein and Prof. Dr. Lu (from left to right) in front of the valve control unit.
Nelson Mandela University - Port Elizabeth, South Africa
Topic of the exchange program: Continuous synthesis of LiCo- and LiMn-oxides as electrodes in lithium batteries.
Continuing the already existing exchange programm between the Nelson Mandela Metropolitan University (NMMU) and the Johannes Gutenberg-University (JGU) in humanities to natural sciences, Ms. Charmelle Snyders visited the group of Prof. Dr. Löwe in Mainz.
Charmelle is a PhD student in chemistry at the group of Prof. Dr. E. Ferg at NMMU. Her interests are the electrode synthesis for (lithium) batteries.
Her objective at JGU was to enhance the synthesis of crystalline Lithium-Cobalt and Lithium-Manganese electrodes for Lithium-Ion batteries and to create a continuous process for synthesizing them using microreaction technology.
The porosity and crystallite size of electrodes is of great importance for high capacity batteries with very fast charge and discharge rates. Due to the fact that the diffusion of the lithium ions limits the capacity and maximum currents of Lithium-Ion batteries, the electrodes have to be as porous and well defined as possible. This property depends on the mixing quality in the production process (a sol-gel-process), which predetermines the crystallite size and porosity of the metal-oxides. The advantages of microreaction technology in this case are obvious.
However, decomposing nitrate salts at temperatures greater than 800° C is not easily achieved in microreactors due to the lack of residence time control, caused by gaseous decomposition products. Therefore, the sol generation was done using ultra fast injection mixing with droplet generation directly afterwards. This sol droplet could then be injected into an 800° C hot oven equipped with a conveyor screw or an oven which is placed upside down. For droplet generation, dry and pre-heated nitrogen gas was used which also enhanced the removal of the decomposition products.
The use of a 3-zone oven easily enabled slow, step-wise heating when necessary. A video of the running process can be seen here: Video (at the very button of the page)
Left: Charmelle Snyders in front of the hot injection unit, right: version 2 of the injection setup with 1000°C hot conveyor screw and droplet injection
Tec de Monterrey - Monterrey, Mexico
Mrs. Waltraut Müller from Mainz University is currently staying at 
the Tec the Monterrey in Mexico for a temporary research position. She is working on her PhD thesis about self-organizing amphiphilic block copolymers of poly-butadieneoxide-block-poly-ethylene.
Mrs. Müller is member of the Graduate class of excellence "Polymers in Advanced Technologies" (POLYMAT) which is operated by the Johannes Gutenberg University, comprising the departments of chemistry, physics, biology and the Max Planck Institute for Polymer Research (MPI-P). The aim of POLYMAT is to provide young researchers with a comprehensive training in advanced methods of synthesis and characterization of polymer materials. This includes research in how to design and optimize polymer-based materials and processes for advanced technologies.
Mrs Müller worked in the Department of Chemical Technology (Microprocess Engineering), supervised by Dr. Alejandro Montesinos, Tec de Monterrey. Email: alejandro_montesinos@itesm.mx