Manufacturing of ceramic membranes for oil-in-water emulsification and oil recovery from wastewater

• Applicant: Dr. Michaela Wilhelm
• Subject Area: Glass, Ceramics and Derived Composites ; Synthesis and Properties of Functional Materials ; Production Automation and Assembly Technology
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 327896934

Emulsions play an important role in product development and formulation, as well as encapsulation of food, pharmaceutical and cosmetic products. Conventional methods for emulsion production and/or separation present some drawbacks, such as the use of high shear stress, high energy demanding and polydisperse droplet size distribution. In this sense, membrane technology emerges as an alternative method to overcome these issues and to produce fine and stable emulsions. Most of the research is focused on polymeric membranes. However, membrane performance still needs developments towards scaling up, mainly regarding fouling behavior. Ceramic membranes arise as effective options for oily wastewater treatment or emulsification, since they exhibit superior resistance to high temperature, high concentration of oil content, foulants, and strong cleaning agents. On the other hand, commercial available ceramic filtration membranes do often have a broad pore size distribution, which lead to inhomogeneous droplet sizes during emulsification. Therefore, new manufacturing techniques still need to be developed for producing membranes that show narrow pore size distribution in the range of 0,1-1 µm and reduced fouling, and consequently increasing membrane lifetime and economic feasibility.The novelty of this project is the manufacturing of polymer derived ceramic membranes, whose properties can be altered on the nanoscale (composition of the precursor) and by the processing technique (shaping, pyrolysis temperature). Two different precursors, polysiloxanes and a polysilazane, will be studied as precursor, mixed with filler particles (e.g. SiO2, SiC) and template particles (PMMA, styrene nanoparticles) and casted or pressed to membranes. Beside the preparation of a defined macropore structure, the surface characteristic will be altered between hydrophilic and hydrophobic by varying materials compositions and the use of different pyrolysis temperatures. For comparison reason the manufacturing of oxidic ceramic membranes (ZrO2, Al2O3) with uniform pore size distribution by a water-based colloidal process (tape casting) will be included. The surface characteristic of these membranes will be adjusted by grafting silanes of different polarity. The influence of the pore size distribution and the surface characteristic will be investigated by emulsification as well as oil recovery from aqueous wastewater. While the preparation of new membrane structures with adjusted pore size and surface characteristic is basically investigated by the German team, the process characterization and a first scale-up of membrane geometries by the Brazilian partner will prepare the manufacturing of affordable and durable ceramic membranes for emulsification and oil recovery.

• DFG Programme: Research Grants
• International Connection: Brazil
• Cooperation Partner: Professor Dachamir Hotza