2017, Issue 63(67), Fasc. 2 (June)
Contents
pages 1- 8 Download
Agri-Wastes – Feedstock for Biorefinery
ANA-MARIA CHEŞCĂ, "Gheorghe Asachi" Technical University of Iaşi,
Faculty of Chemical Engineering and Environmental Protection
BOGDAN
MARIAN TOFANICĂ, "Gheorghe Asachi" Technical University of Iaşi, Faculty of
Chemical Engineering and Environmental Protection
ADRIAN CĂTĂLIN PUIȚEL,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection,
puitelac@tuiasi.ro
DAN
GAVRILESCU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of
Chemical Engineering and Environmental Protection
pages 9 - 18 Download
Abstract
Straws and stalks are important categories of
lignocellulosic agri- wastes. The availability of these materials is high,
taking into account their extended cultivation. Their chemical composition
represents an argument for their use as feedstock for papermaking fiber
production. In this study, soda pulping process was employed for
delignification of wheat straws (Triticum aestivum), corn stalks (Zea mays),
rapeseed (Brassica napus) and sunflower (Helianthus annuus). The obtained
pulps have been characterized from the perspectives of papermaking. Lignin
separated from spent liquors resulted from pulping of agri-wastes is an
alternative to increase overall process feasibility. In such context, the
separated spent liquors were acid treated for lignins separation, which were
further characterized by UV and IR spectroscopy techniques and gel
permeation chromatography. The obtained results are important in
establishing the potential usage of such lignins.
Keywords: straw;
stalks; pulp; paper; lignin.
XRD Analysis of the Structural Properties of Layered Double Hydroxides Comprising Zn and Al Partially Substituted with Cu and Ce and their Derived Mixed Oxides
DIANA GILEA, "Gheorghe Asachi" Technical University of Iaşi, Faculty of
Chemical Engineering and Environmental Protection,
gilea.diana91@gmail.com
GABRIELA CARJA,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection,
gcarja@ch.tuiasi.ro
pages 19 - 25 Download
Abstract
The structural changes of layered double hydroxides (LDHs), when
zinc was partially substituted by copper and aluminum was partially substituted
by cerium in the layer of the LDHs matrix was monitored by X-ray diffraction
(XRD), while the bulk composition of the studied samples was confirmed by X-ray
fluorescence (XRF). The substituted samples preserved the layered structure, but
the constrictions of the network appeared as a result of the substitution. After
calcination at 850°C for 7 h, well crystallized mixed oxides containing copper
and cerium were formed. The results point out that the calcination temperature
is important to establish the structural features of the resulting mixtures of
mixed oxides.
Keywords: layered double hydroxides; XRD; mixed oxides;
copper; cerium
Diffusion Coefficients from Sorption Experimental Data
IONUŢ OVIDIU FORŢU, "Gheorghe Asachi" Technical University of Iaşi,
Faculty of Chemical Engineering and Environmental Protection
RODICA SERETEANU,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection
EUGENIA TEODORA IACOB
TUDOSE, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection, etudose@tuiasi.ro
IOAN MĂMĂLIGĂ,
"Gheorghe Asachi"
Technical University of Iaşi, Faculty of Chemical Engineering and
Environmental Protection
pages 27 -39 Download
Abstract
The diffusion of volatile components trough polymers or other
materials of different geometry (plane, spherical or cylindrical) is essential
for many industrial applications. In order to characterize the mass transport in
these processes, an effective diffusion coefficient is needed. The diffusion
coefficients estimation, usually using indirect methods, is based on
experimental measurements of volatile components diffusion, retained on
sorbents. Hence, the diffusivity is assessed by measuring pressure, sample
weight or concentration, externally. These calculations require an appropriate
model which describes the processes and the occurring transport phenomena. In
this paper we present estimations of the diffusion coefficients using
theoretical and experimental methods. These experimental methods are based on
the kinetics of the solvent retention within materials of different shapes.
Keywords: cylindrical geometry; diffusion; planar geometry; process; spherical
geometry.
Conformational Analysis of Polysiloxanes Substituted with Azobenzene
SIMONA CIOBOTĂRESCU, "Gheorghe Asachi" Technical University of Iaşi,
Faculty of Chemical Engineering and Environmental Protection, University of Angers, France
Physics Department
ELENA-LUIZA EPURE,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection, lepure@tuiasi.ro
NICOLAE HURDUC,
"Gheorghe
Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and
Environmental Protection
pages 41 - 49 Download
Abstract
This work presents a molecular modeling study with regard to the
conformational behaviour of azo-polysiloxane in function of the content in cis
azobenzene (CA). Molecular dynamics was used to carry a NVT simulation of
azobenzene substituted polysiloxane in bulk. Conformational analysis was
performed to determine how the CA concentration affects the polymeric chain’s
three-dimensional structure. The radius of gyration was found not to change with
the variation of CA content, while the potential energy increased with the
increasing of CA percentage. The low change in free volume from one structure to
another supports the constant radius of gyration. The correlated results suggest
that the CA brings conformational tension on the structure. The macromolecular
chain is unable to position itself in a less structural conflictive arrangement
and determines a growth in potential energy. More studies are needed for further
investigation and to link these findings with simulations in layer and solution.
Keywords: molecular modelling; azo; isomerisation; configuration.
Iron Based Layered Double Hydroxide and its Calcined Derivate as Efficient Photocatalysts in Phenol Removal
ELENA-FLORENTINA GROSU, "Gheorghe Asachi" Technical University of Iaşi,
Faculty of Chemical Engineering and Environmental Protection,
elena_grosu89@yahoo.com
GABRIELA CARJA,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical
Engineering and Environmental Protection,
gcarja@ch.tuiasi.ro
pages 51 - 60 Download
Abstract
We report here the fabrication of novel semiconductor
photocatalysts with high efficiency in the advanced oxidation reactions. Layered
double hydroxides (LDHs) are nontoxic and environmental friendly anionic clays
studied due to their photoresponses under UV, visible and solar irradiation. In
this work ZnFeAlLDH and the derived mixed oxides obtained after calcination,
denoted as ZnFeAl750 were synthesized and used for the first time in the process
of phenol photodegradation under irradiation with a solar simulator. The
structure and the optical properties of the catalysts were studied by XRD, FTIR
and UV-Vis techniques. The photocatalytic tests were done using a solar
simulator. The results demonstrate that ZnFeAlLDH has a specific hydrotalcite
structure that transformed into highly homogeneous mixed oxides after
calcination at 750°C. The tested catalysts are able to absorb light starting
from the red region of the spectrum. Results show that the maximum
photodegradation of phenol was reached with ZnFeAl750, which removed 70% from
the initial concentration of the phenol pollutant after 6 h of irradiation with
solar light.
Keywords: LDHs; photocatalyst; mixed oxides; pollutant; phenol;
solar photodegradation.
Habilitation Thesis Summary:
Design of High Performing
Materials with Increased Thermal Stability: Structure-Property Relationship
and Degradation Mechanism
GABRIELA LISA, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, gapreot@ch.tuiasi.ro
pages 61 - 64 Download