The third research area of the CEEC Jena – clean tech –focuses on various membrane technologies. Amongst others, polymer-based membranes are investigated, which are obtained, e.g., via the combination of block copolymers.
In addition, ceramic membranes – a core competence of the Fraunhofer Institute for Ceramic Technologies and Systems IKTS Hermsdorf play an important role. For example, nanoporous ceramic materials for substance separation and membranes for high-temperature separation are being investigated. Another research aspect is water technologies.
Cavitation describes the formation, growth and implosive collapse of vapor or gas bubbles in a liquid. It creates chemical and physical effects, which are used in a broad range of applications. Chemical effects are accompanied by the so-called hot spots, which are located in the center of the collapsing bubbles and show temperatures up to 5000 K and high pressures up to 1000 atm. As a result, pyrolytic degradation of volatile organic compounds (VOCs) as well as the homolytic cleavage of water molecules inside the hot spot occur. The formed hydroxyl radicals with their high oxidation potential are able to degrade micropollutants like pharmaceuticals and hormones, effectively. Therefore, the cavitation process belongs to the Advanced Oxidation Processes (AOP). The physical effects of cavitation are mainly based on shear forces and micro streams, which form the so-called micro jets at phase boundary layers. Thus, cavitation shows a great potential for different mixing and cleaning processes and is able to accelerate mass transport limited reactions.
In our working group hydrodynamic as well as acoustic cavitation and their combination as a hybrid method, the so-called Hydrodynamic-Acoustic-Cavitation (HAC) are used in different research fields. Mainstay is the acoustic or optical cavitation field analysis with hydrophones and chemiluminescence and the reactor development/optimization for specific applications.
At the CEEC, cavitation technologies are applied in the process intensification of different transport limited reactions or multiphase systems. The synthesis of nanoparticles or the coating of various surface materials are part of the research activities as well as the disintegration and pretreatment of different biomass feed stocks for increasing the gas yield and reducing residuals.
In the research field of renewable resources, we focus on energetic and material related utilization of different organic feedstock.
For the process intensification of biogas production, efficient technologies are tested, which accelerate the process limiting hydrolysis step. For example, cavitation technologies can be used as a pretreatment process, due to the disintegration of the biomass. Beside an increased biogas production, this leads to reduced residuals and to noticeable improvements in subsequent processes. This is the reason, why pretreatment steps are mentioned to be the key technologies for an efficient material and/or energetic utilization of biomass.
Fuels derived from renewable resources contributes to guarantee of the human mobility, combined with different inherent advantages and disadvantages. In this area, we try to develop new concepts for the synthesis of biofuels, which use biogenic residual and wastes as well as alternative energy inputs.
For the development of efficient and resource saving processes different approaches with pioneering regulation and control systems are implemented in the research projects. Thus, the energy input (e.g. disintegration/biofuels synthesis) can be adjusted dynamically at the actual conditions like costs and qualities of feed stock, price of electricity, season whereas the process works at the optimal (economic/ecologic) operation point permanently.
The development of pioneering and innovative technologies for the treatment of industrial and municipal wastewater as well as the removal of contaminants (e.g. micro pollutants, pharmaceuticals) in different aquatic systems comes more and more in the fore of the public and science.
One of the main research topic in the working group focusses on Advanced Oxidation Processes (AOP), where oxygen-containing species with high oxidation potential are generated and used for the degradation of different organic pollutants. There exists different AOP-technologies like photo(cata)lysis, ultrasound, hydrodynamic cavitation, electrochemical and pyro- as well as piezoelectric methods. Depending on the substrate flow and concentration of the contaminants, we use different AOP-technologies or combinations of these single methods for the oxidative degradation of anthropogenic (micro)-pollutants like pharmaceutical or industrial chemicals. Therefore, we need sensitive analytical methods for the detection and quantification of the oxidizing species, the pollutants and their transformation products. Next to AOP-processes, we focus on the application of carbon-based adsorption material for the adsorptive separation of different pollutants.
Another research topic is the resource recovery from wastewater. Phosphor, as a finite resource and essential macronutrient, is of particular interest, as it is closely linked to food security. To ensure the future phosphor supply, our working group investigate different phosphor recovery strategies. Moreover, membrane technologies and especially the modification of the separation layer for the separation of oil/water emulsions and produced water plays a crucial role in this research field.
The topic microplastic and its implication as well as the long-term effects on different ecosystems attracted considerable public attention over the last few years. The harmful effect on the fauna due to ingestion is already known, but long-term effects can only be estimated. Another less known effect is the (de-)sorption behavior of micro plastic with respect to photochemical and mechanical ageing. The hydrophobic surfaces of the polymer particles are able to adsorb and accumulate hydrophobic organic compounds such as different industrial chemical and pharmaceuticals. The ageing process effects the sorption capacity and therefore, we try to increase the knowledge of the sorption kinetics under different environmental conditions and develop models for the assessment of the pollutant loading.