Nanoporöse hochvernetzte Polymere und Aktivkohlen in selektiven Adsorptions- und Nanofiltrationsprozessen zur Anwendung in biogenen Wertschöpfungsketten
- Nanoporous hypercrosslinked polymers and activated carbons in selective adsorption and nanofiltration processes for bio based value streams
Schute, Kai; Palkovits, Regina (Thesis advisor); Rose, Marcus (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, RWTH Aachen University, 2020
Hypercrosslinked porous polymers (HCP) from aromatic building blocks and polymer based spherical activated carbons (PBSAC) create a promising material basis for usage in a variety of separation processes. Especially adsorption and membrane processes. Biobased value chains on the other hand often create challenging separation processes, in which classical approaches face certain limitations. In this context the presented work delivers exemplary solutions in such fields of application. Initially a novel way of synthesizing a variety of HCP using conventional brønsted acids is developed. The obtained materials are then characterized with focus on the textural properties showing high hydrophobic surfaces and specific surface areas with above 1800 m² g-1. The HCP as well as PBSAC were then tested in adsorption processes with focus on 5-hydroxymethylfurfural (5-HMF)/fructose as well as itaconic acid/glucose. Both batch and continuous sorption experiments show high selectivities towards 5-HMF and itaconic acid by using HCP and PBSAC. Even the use of real fermentation broths contained the selectivity. Studies on the surface polarity furthermore enabled the description of the adsorption behaviour which was enabled through the targeted correlation between adsorption experiments and the polarity of different carboxylic acids. A reversed trend between the capacity of the adsorption and the dipole moment were observed presenting a semi quantitative way on estimating sorption selectivities. Lastely, the use of the mixed matrix membrane concept was used to develop HCP based membranes. Their usability was shown in nanofiltration applications on water based systems. Moderate rejections were presented through different dyes.