68th Annual Gaseous Electronics Conference/9th International Conference on Reactive Plasmas/33rd Symposium on Plasma Processing
Volume 60, Number 9
Monday–Friday, October 12–16, 2015;
Honolulu, Hawaii
Session PR4: Electron Collisions
1:30 PM–3:00 PM,
Thursday, October 15, 2015
Room: 303 AB
Chair: Igor Bray, Curtin University
Abstract ID: BAPS.2015.GEC.PR4.2
Abstract: PR4.00002 : Electron Scattering by biomass molecular fragments
2:00 PM–2:30 PM
Preview Abstract
Abstract
Author:
Marco Lima
(UNICAMP)
The replacement of fossil fuels by biofuels from renewable sources may not
be a definite answer for greenhouse gas emissions problems, but it is a good
step towards a sustainable energy strategy. Few per cent of ethanol is being
mixed to gasoline in many countries and in some of them, like Brazil, a very
aggressive program has been developed, using, in large scale, flex fuel
engines that can run with any mixture of gasoline and ethanol, including
100{\%} ethanol. Important points are how to produce ethanol in a
sustainable way and with which technology? Biomass is a good candidate to
enhance the first generation (produced from Corn in USA and from sugarcane
in Brazil) production towards the so-called second-generation ethanol, since
it has cellulose and hemicellulose as source of sugars. In order to liberate
these sugars for fermentation, it is important to learn how to separate the
main components. Chemical routes (acid treatment) and biological routes
(enzymatic hydrolysis) are combined and used for these purposes. Atmospheric
plasmas can be useful for attacking the biomass in a controlled manner and
low energy electrons may have an important role in the process. Recently, we
have been studying the interaction of electrons with lignin subunits
(phenol, guaiacol, p-coumaryl alcohol), cellulose components, $\beta
$-D-glucose and cellobiose ($\beta $(1-4) linked glucose dimer) and
hemicellulose components [2] ($\beta $-D-xylose). We also obtained results
for the amylose subunits $\alpha $-D-glucose and maltose ($\alpha $(1-4)
linked glucose dimer). Altogether, the resonance spectra of lignin,
cellulose and hemicellulose components establish a physical--chemical basis
for electron-induced biomass pretreatment that could be applied to biofuel
production.
In order to describe a more realistic system (where molecules are ``wet''),
we have obtained the shape resonance spectra of phenol-water clusters, as
obtained previously from elastic electron scattering calculations. Our
results, obtained in a simple model (phenol in the presence of one and two
water molecules), indicate that the well-known indirect mechanism for
hydrogen elimination in the gas phase is significantly impacted on by
microsolvation, due to the competition between vibronic couplings on the
solute and solvent molecules. This fact suggested how relevant the solvation
effects could be for the electron-driven damage of biomolecules and the
biomass delignification. We have also discussed microsolvation signatures in
the differential cross sections that could help to identify the solvated
complexes and access the composition of gaseous admixtures of these species.
In a collaboration project involving Australia (within the Brazilian Science
Without Borders program), Portugal, Spain and Brazil, we have focused on
obtaining theoretical and experimental electronic excitation cross sections
of phenol and furfural for 10-50 eV electron impact energies. Convergence on
electronic multichannel coupling stands as the biggest challenge to obtain
agreement between theory and experiments. In my presentation, I will discuss
the current status of this project.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2015.GEC.PR4.2