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Adsorption und Rückgewinnung organischer Säuren aus wässrigen Lösungen mittels Hydrotalcit am Beispiel der Bernsteinsäure

 
: Schöwe, Nick

:
Fulltext urn:nbn:de:hbz:294-45671 (8.2 MByte PDF)
MD5 Fingerprint: 0eba74d2fe008e6e15d9762a33a14243
Created on: 30.4.2016


Bochum, 2015, III, 162 pp.
Bochum, Univ., Diss., 2015
German
Dissertation, Electronic Publication
Fraunhofer UMSICHT Oberhausen ()
adsorption; Säure; Rückgewinnung; Bernsteinsäure; wässrige Lösung

Abstract
The present study focuses on the removal and recovery of organic acids by adsorption with hydrotalcite using succinic acid as an example. The aim is to develop a sorption process with hydrotalcite as inorganic adsorbent and, hence, to study scientifically the selective isolation of organic acids from aqueous solutions (fermentation broth). This study has allowed it to successfully improve the application of powdered hydrotalcite by granulation of the material, and thus to permit the applicability in customary chromatographic columns. Within this study the granules are characterized in detail concerning their specific surface area, pore size and pore structure. Adsorption isotherms of granulated hydrotalcite are calculated in order to give a description of the adsorption equilibrium and to draw a direct comparison of these with isotherms of commercially available anion exchange resins. The reusability of the granules is shown by sequenced sorption cycles in gravimetric tests. The granules can be thermally regenerated for reuse. Research on lactic acid as an example for monocarboxylic acids has revealed the applicability of the granules for adsorption of further monocarboxylica cids. After optimization of process parameters up to 98 % of the previous bound organic acid can be recovered in desorption solution. For prediction of the performance of the hydrotalcite granules a mathematical model is implemented to simulate the adsorption process of succinic acid on these granules. The reproduction of the experimental performance of the hydrotalcite granules is possible by the simulation of breakthrough curves of succinic acid solution. Against the background of an industrial use, the event of competition for the adsorption of succinic acid on hydrotalcite granules by other anions and molecules are being examined using carboxylic acid solutions with interfering components. The role of phosphate is critical, since it is selectively adsorbed along with organic acids. The decrease of the operating adsorption capacity results from components which interfere with the adsorption process, but are not necessarily bound. Moreover, this decrease does not necessarily have to correspond to the sum of influences of the individual components. A possible process for succinic acid production using A. succiniciproducens and a continuous in situ removal of succinic acid using hydrotalcite granules is considered theoretically. On the basis of these considerations, the significant increase in the maximum achievable amount of the end product is shown. The practical coupling of column unit and fermentation system leads to an integrative downstream process with the option of continuous removal of the succinic acid.

 

Im Rahmen der Arbeit wird die Entwicklung eines adsorptiven Verfahrens mit Hydrotalcit als anorganisches Adsorbens zur selektiven Isolierung von organischen Säuren aus wässrigen (Fermentations-) Lösungen vorgenommen. Die Anwendbarkeit von pulverförmigem Hydrotalcit in handelsüblichen Chromatographiesäulen wird durch eine Granulierung des Materials ermöglicht und das Adsorbens ausführlich charakterisiert. Am Beispiel der Bernsteinsäure wird ein Modell zur Simulation des Adsorptionsvorgangs implementiert. Experimentell werden die Einflüsse von relevanten Anionen und Molekülen auf die Adsorption von organischen Säuren bestimmt. Anhand des Fermentationsprozesses von Bernsteinsäure mit A. succiniciproducens wird ein mögliches Gesamtverfahren mit integrierter Produktabtrennung über Hydrotalcit-Granulate betrachtet. Die Kopplung von Säuleneinheit und Fermentationssystem führt zu einem integrativen Aufreinigungsverfahren, bei dem eine kontinuierliche Abtrennung von Bernsteinsäure möglich ist.

: http://publica.fraunhofer.de/documents/N-370052.html