Ionic liquids for the development and conversion of sustainable resources

Ioniq Liquid — Ioniq Liquid
Image Credit: Susanne Stein

WSS Resources Team — WSS Resources Team
Image Credit: WSS Resources, FU Berlin

The Swiss Werner Siemens Foundation (WSS), which already supports numerous outstanding innovations and extraordinary ideas in technology and the natural sciences, is giving new impetus to sustainable chemistry in Berlin with its ten-year funding commitment.

In recent years, researchers led by Sebastian Hasenstab-Riedel from Freie Universität Berlin have developed a technology that makes it much easier and more energy-efficient to store, transport, and process chlorine.

Together with his colleagues, organic chemist Rainer Haag, mineralogist Timm John, and electrochemist Siegfried R. Waldvogel, Sebastian Hasenstab-Riedel and his team are working on new fields of application for chlorine storage technology. In this way, they are contributing to the transformation of chemistry in a variety of ways.

The Werner Siemens Foundation

The Werner Siemens Foundation is based in Zug, Switzerland. Since 2003, its philanthropic arm has been providing substantial funding to support outstanding innovations and talented young researchers in the fields of technology and natural sciences. The research projects it supports address relevant problems of our time and are on the threshold of applicability. There are currently two dozen such projects underway. They all have a duration of at least five years.

In spring 2023, chemist Prof. Dr. Sebastian Hasenstab-Riedel and a team from Freie Universität Berlin received one of six research awards worth one million Swiss francs, with which the foundation honored research ideas on technologies for sustainable resource use.

→ Werner Siemens Foundation

Chloride-based reactive Ionic Liquids

Chlorspeicher

Ionic Liquids are salts that are liquid at room temperature and that can absorb large amounts of chlorine with low vapour pressure. This type of storage medium chemically binds chlorine gas or hydrogen chloride in liquid form. When slightly heated, the chlorine is released, making it available for production processes, and the liquid salt can be reused. In future, this will make it easier and safer to store, transport, and produce chlorine, also by using renewable electricity.

Recycling von Hightech-Metallen

In Elektromotoren, Windturbinen oder Handys stecken große Mengen an wertvollen Metallen, etwa Seltenerdmetalle. «Wir wollen Methoden entwickeln, um diese Rohstoffe einfach aus den Produkten herauszulösen und zu rezyklieren», sagt Mineraloge Timm John. Erste Versuche zeigen, dass sich mit der Ionischen Flüssigkeit Hightech-Metallverbindungen schon bei niedrigen Temperaturen auflösen und die einzelnen Metalle abscheiden lassen.

Conversion of biomass

Every year, four million tons of glycerin are produced as a by-product of biodiesel production; paper production generates as much as 100 million tons of lignin as a residual material. According to chemistry professor Rainer Haag, such biological residues can be converted into valuable chemical raw materials or functional materials with the help of ionic liquids.

Turning contaminated landfills into resource-rich sites

“Using electrochemical processes, we can remove chlorine from existing compounds and store it again in ionic liquid,” says Siegfried R. Waldvogel, director of the Max Planck Institute for Chemical Energy Conversion and guest professor at Freie Universität Berlin. Examples of such chlorine-containing waste include pesticide waste from the 1950s to the 1990s and chlorine-containing polymers such as PVC, which is widely used in construction. Millions of tons of this waste are stored in easily accessible landfills because recycling has been too expensive until now. With the help of the chlorine storage facility, these contaminated sites suddenly become attractive raw materials and can further advance the defossilization of the chemical industry. The advantage of this method is that the carbon skeleton is completely preserved and available for further use.