Untersuchungen zur Herstellung von agglomerierten Anionenaustauschern auf Styrol- und Methacrylat-Basis

The support particles were obtained by functionalizing a highly crosslinked PS-DVB-resin with sulfuric acid. The reaction proofed to be reproducible. The emulsion polymerization of styrene-type latex-particles was examined using the VBC-DVB monomer system. Critical process parameters were varied systematically. The products were characterized by photon correlation spectroscopy and scanning electron microscopy. The synthesis of latex particles was transferred successfully to GMA-EGDMA, THFMA-EGDMA and HPMA monomer systems obtaining functional particles for latex-agglomerated anion exchangers. Coagulation during functionalization of latex particles presented a difficulty in reproduction of VBC-DVB-latex-columns. This was also the cause of high backpressure in methacrylate latex columns leading to early performance loss in long term tests. The characterization of the different column-types showed that substitution of the styrene-type VBC-DVB-latex with methacrylate-latex significantly improves the peaksymmetry of polarizable anions such as Bromide and Nitrate. Additionally the resolution of the Fluoride peak and injection peak was achieved and identical efficiency for eight inorganic anions was observed. The chemical structure of the latex functional group influenced the selectivity of polarizable and multivalent anions. These effects are due to different charge densities and hydrations. In addition to that, on VBC-DVB-columns an increased peaktailing was observed with the polarity of the quaternary ammonium-ion.