Valorization of different types of biomass via polyoxometalates to formic acid derivatives and desired solid products

This dissertation deals with the utilization of various biomass using polyoxometalate (POM) catalysts. Formic acid as well as its derivatives and solid valuable products like proteins from the ProFA process and cellulose from the POM-ionosolv process were produced. The solid value products depended on the starting biomass used. A cellulose-rich solid was produced from lignocellulosic biomass and a protein-rich solid from algae-based biomass. The first part of the dissertation deals with the production of cellulose-rich solids and formic acid or its derivatives. For this purpose, the lignocellulosic biomass was first fractionated using different methods (organosolv and ionosolv) which were subsequently compared with regard to further oxidation using POM catalysts. The ionosolv method proved to be a promising method as more formic acid could be produced. Using a tributylmethylphosphonium methylsulfate ionic liquid (IL) and methanol as co-solvent, a white, cellulose-rich solid with over 90 % glucan was successfully produced. Furthermore, the production of formic acid/formic acid derivatives using POM catalysts in different solvents was investigated. In particular, the solvent-catalyst interaction of the solvent best suited for the production of cellulose-rich solids was investigated using various analytical techniques. It was found that a POM-IL salt forms in the IL/methanol solvent in-situ, which has different selectivities to methyl formate as a formic acid derivative depending on the IL. In the second part of the dissertation, the production of protein-rich solids from macroalgae was investigated using the OxFA (Oxidation of lignocellulosic biomass to formic acid) process. Different types of macroalgae (red algae (Porphyra dioica), brown algae (Fucus vesiculosus) and green algae (Ulva fenestrata)) as well as two different POM catalysts (H5PV2Mo10O40 and H8PV5Mo7O40) were screened. Applying the most promising combination, Porphyra dioica and H5PV2Mo10O40, an optimization study was performed using a Box-Behnken Design of Experiments. This allowed the formic acid yield to be increased from 8.6 % to 16.4 % in combination enabling a protein recovery of 59.5 %. In order to further increase the protein recovery, three promising extraction methods (alkali hydrolysis, ultrasound-assisted extraction and IL extraction) were tested and optimized. Ultrasoundassisted extraction was identified as the best method enabling a protein recovery of 87.2 %. The findings of this dissertation have helped to evaluate the possibilities of POM catalysts in biorefinery-like concepts and to further develop these concepts.

Subjects

lignocellulosic biomass

algal biomass

polyoxometalates

formic acid

valorization

DDC Class

660.6: Biotechnology

5: Natural Sciences and Mathematics::

540: Chemistry

660.6: Biotechnology

660: Chemistry; Chemical Engineering

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

thesis_Stefanie Wesinger_Valorization of different types of biomass via polyoxometalates to formic acid derviatives and desired solid products.pdf

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20.97 MB

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Valorization of different types of biomass via polyoxometalates to formic acid derivatives and desired solid products