h1

% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Keller:822014,
      author       = {Keller, Robert Gregor},
      othercontributors = {Wessling, Matthias and Goetheer, Earl},
      title        = {{F}enton’s chemistry in biorefineries},
      volume       = {14 (2021)},
      school       = {Rheinisch-Westfälische Technische Hochschule Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2021-06495},
      series       = {Aachener Verfahrenstechnik Series},
      pages        = {1 Online-Ressource : Illustrationen, Diagramme},
      year         = {2021},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, Rheinisch-Westfälische Technische
                      Hochschule Aachen, 2021},
      abstract     = {Today, the energy, industrial, and transport sectors rely
                      heavily on fossil resources as energy and carbon source. An
                      economy based on fossil carbon leads to high emissions of
                      green house gases, such as carbon dioxide, which cause the
                      anthropogenic climate change. In order to prevent a further
                      increase in the average global temperature and combat the
                      adverse impacts it entails, power-to-x technologies and
                      biorefineries are on the rise. Until now, the technological
                      breakthrough of biorefineries is hampered by numerous
                      barriers: For example, harsh chemical pretreatment
                      conditions with the use of harmful solvents for biomass
                      fractionation lead to high investment costs and high
                      complexity due to non-integrated processes. This thesis
                      presents integrated biorefinery processes based on green
                      solvents, lignin-first conceptualization, and the coupling
                      of electrochemical processes to cellulose depolymerization.
                      Lignin was extracted from beech wood chips by employing
                      hydrotropic and deep eutectic solvents. Subsequently, lignin
                      was depolymerized via Fenton’s chemistry in the
                      hydrotropic solvent and coupled with an in situ extraction.
                      Fenton’s chemistry was additionally investigated for the
                      depolymerization of cellulose that was studied using the
                      model compound cellobiose. The process was electrified as
                      electro-Fenton and coupled with an in situ membrane
                      separation. Lignin was extracted with up to $80\%$ yield
                      with deep eutectic and hydrotropic solvents. The highest
                      yields were obtained with high pretreatment temperatures of
                      120 and 200 °C, respectively, and small wood chip sizes.
                      The lignin that was extracted in a hydrotropic solution was
                      depolymerized to aromatics in the solvent itself. Even
                      though the depolymerization was successful and an in situ
                      extractionwas employed, only low amounts of value-added
                      aromatics were obtained. Organic acids were found to be the
                      main product of the depolymerization with a yield of up to
                      $30\%$ based on the initial lignin concentration. Glucose
                      was successfully formed by the depolymerization of
                      cellobiose using Fenton’s reagent. However, the
                      selectivity was limited to values below $30\%$ for all
                      parameters tested in this work. With increasing reaction
                      time, the selectivity decreased continuously due to the
                      oxidation of glucose by Fenton’s reagent. Thus, a
                      nanofiltration separation stage was coupled to the
                      (electro-)Fenton process. Experimental and simulation
                      results demonstrated that the separation prevents
                      overoxidation of glucose while simultaneously retaining the
                      reactant cellobiose and the catalyst iron in the Fenton
                      reactor. This thesis emphasizes the need for integrated
                      processes in biorefineries. Electrochemical processes
                      provide the opportunity to drive reactions by an electrical
                      potential that is powered by renewable electricity. When
                      using Fenton’s chemistry for the formation of value-added
                      compounds a strong focus must be laid on in situ separation
                      techniques to prevent degradation of the target products.},
      cin          = {416110},
      ddc          = {620},
      cid          = {$I:(DE-82)416110_20140620$},
      pnm          = {DFG project 39030946 - EXC 236: Maßgeschneiderte
                      Kraftstoffe aus Biomasse (39030946) / DFG project 390919832
                      - EXC 2186: Das Fuel Science Center – Adaptive
                      Umwandlungssysteme für erneuerbare Energie- und
                      Kohlenstoffquellen (390919832)},
      pid          = {G:(GEPRIS)39030946 / G:(GEPRIS)390919832},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      doi          = {10.18154/RWTH-2021-06495},
      url          = {https://publications.rwth-aachen.de/record/822014},
}