Using XRD and TG/DTG/DSC Studies to Follow the Structural Changes
Induced by the Substitution of Al3+ with Ga3+ in 2-D Zn-rich Layered Double
Hydroxides Matrices
EUGENIA CORINA IGNAT, “Gheorghe Asachi” Technical University of Iasi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection GABRIELA CARJA, “Gheorghe Asachi” Technical University of
Iasi, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection,
gcarja@ch.tuiasi.ro
Abstract Changes in the structural characteristics of ZnAlLDHs, when
Al3+ was replaced by Ga3+ and the structural features of the mixed oxide
derived by calcination were rigorously assessed using X-ray diffraction
(XRD) and thermogravimetric analysis (TG/DTG/DSC). The results of XRD
analysis point out the formation of an LDH phase, without any impurity, with
slight differences between samples prepared with specific trivalent cations,
in relation to the higher volume of Ga compared to Al, due to their
different cationic rays. After the calcination, the LDH structure collapsed
and the characteristic XRD reflections of the mixed oxides were obtained.
The results of the TG/DTG/DSC analysis indicate that the mass loss reported
in terms of moles was almost similar for ZnAlLDH and ZnGaLDH. This
demonstrates that the adsorbed water, CO2 and HO- content are similar in the
substituted LDH. Hence, this study has revealed that both the composition of
the Zn-rich LDHs and the calcination temperature are important parameters
for tailoring the structural characteristics of the newly formed
ZnO/Ga2O3/ZnGa2O4 homogeneous mixed oxides. Keywords: Layered double
hydroxides, mixed oxides, X-Ray diffraction, thermogravimetric analysis,
structural properties
An Approach of Recycling Textile Waste with Industrial Applications
FLORIN ST. C. MUSTATA, “Gheorghe Asachi” Technical University of Iaşi,
Faculty of Industrial Design and Business Management, Iaşi, Romania,
florinmustata@gmail.com ANTONELA CURTEZA, “Gheorghe Asachi” Technical University of Iaşi, Faculty of
Industrial Design and Business Management, Iaşi, Romania
Abstract The fashion industry output a great volume of waste caused
by mass production. A great percentage of those garments are disposed in
land fields after use, instead of being recycled. In order to prevent the
generation of this enormous quantity of waste, the paper will explore
methods or strategies to recycle natural and synthetic textile waste.
Industrial methods used to recycle textile waste evaluated are: textile
recycling to cellulose, separation and conversion of textile waste from
wool-polyester and cotton-polyester blends. Associated Recyclability
Potential Index (RPI) will be evaluated. Some methods to separate textile
waste use selective digestion of wool fibers from wool-polyester mixtures.
Some applications use the keratinize in two step process with addition of a
reducing agent. The polyester fibers are recovered after the process. We can
see that, after the process, the natural fibers are decomposed and the
polyester fabric is in good conditions, then can be used for new garment
production. Keywords: Textile waste, environmental strategies,
recycling, wool-polyester blends, cotton-polyester blends
Spinning Disc Technology for Textile Wastewater Treatment:
Characteristics, Modeling/Optimization Study
CARMEN ZAHARIA, “Gheorghe Asachi” Technical University of Iasi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection EUGENIA TEODORA IACOB-TUDOSE, “Gheorghe Asachi” Technical
University of Iasi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection,
etudose@ch.tuiasi.ro
Abstract The spinning disc (SD) technology has been used for a
number of applications due to its improved attributes. This study focuses on
applying SD technology to a textile wastewater treatment in order to
improve, without any other additional treatment, its suspended solids and
color contents. An experimental planning based on a central compositional
rotatable matrix of 23 order is used for modeling. Also, the optimal values
of all considered process variables (independent ones: flow rate (z1) within
10-30 L/h experimental range, disc rotational speed (z2) in 200-1100 rpm
range, operating time (z3) within 5-30 min range) were established together
with the dependent ones: treatment degree of suspended solids content (Y1)
and discoloration (Y2). The SD treatment feasibility was reasonably good
(max. Y1 = 45.07% and Y2 = 26.59%). Thus, it can minimize color and solids
loads within a relatively short time period and can be used within the
primary treatment step. Keywords: discoloration, flow rate, spinning
disc (SD) technology modeling and optimization, suspended solids removal,
textile wastewater treatment
Environmental Friendly Manufacturing the Geopolymer Foam from
Aluminosilicate Wastes Completely Excluding the Cement
BOGDAN VALENTIN PĂUNESCU, Consitrans SA Bucharest, Romania ADRIAN
IOANA, University Politehnica of Bucharest, Faculty of Science and Materials
Engineering, Romania LUCIAN PĂUNESCU, Cosfel Actual SRL Bucharest,
Romania,
lucianpaunescu16@gmail.com
Abstract Geopolymer foam was produced by foaming with hydrogen
peroxide (H2O2) of aluminosilicate mixture composed of fly ash and clay
brick waste activated with an alkaline activator (water glass and sodium
hydroxide in aqueous solution). Other mixture components were expanded
perlite as a siliceous additive, a usual fine aggregate (sand), and a less
frequently used surfactant (olive oil). The characteristics of the
geopolymer foam were: density in the range of 420 - 560 kg/m3, porosity
between 71.5 - 76.9%, thermal conductivity within the limits 0.080 - 0.122
W/m·K, and compressive strength between 4.1-5.6 MPa. The low values of
density and thermal conductivity indicated good thermal insulation
properties of the geopolymer foam, similar to those of this type product
presented in the literature. The residual materials contributed to the low
level of costs and the complete replacement of ordinary cement in the
concrete composition led to the significant reduction of CO2 emissions.
Keywords: geopolymer foam, aluminosilicate binder, coal fly ash, hydrogen
peroxide, alkaline activator
Current Trends in The Radar Absorbing Materials
ELISA APOSTOLESCU, University Politehnica of Bucharest, Faculty of
Aerospace Engineering, Romania MIHAELA AURELIA VIZITIU, “Gheorghe
Asachi” Technical University of Iasi, “Cristofor Simionescu” Faculty of
Chemical Engineering and Environmental Protection, Iaşi, Romania,
mihaela-aurelia.vizitiu@academic.tuiasi.ro
Abstract The study of materials with properties of reducing or
blocking electromagnetic radiation used in RADAR detection has gained
momentum in recent years, especially after the discovery of graphene and
metamaterials. The paper aims to present the main absorbing radar materials,
the classic ones based on metal or carbon particles but also the recently
discovered ones, based on complex mixtures of materials with good
electrical, magnetic and thermal properties with dielectric materials.
Keywords: Radar absorbing materials (RAM), graphene, metamaterials,
electrical conductivity
Bio-Foaming Agent Used for Preparing Cellular Glass from Recycled
Residual Glass
LUCIAN PĂUNESCU, Cosfel Actual SRL Bucharest, Romania,
lucianpaunescu16@gmail.com SORIN-MIRCEA AXINTE, Daily Sourcing & Research SRL Bucharest, Romania;
Department of Applied Chemistry and Materials Science, University
Politehnica of Bucharest, Romania ADRIAN IOANA, Faculty of Science and
Materials Engineering, University Politehnica of Bucharest, Romania ENIKÖ VOLCEANOV, Faculty of Science and Materials Engineering, University Politehnica of Bucharest, Romania; Metallurgical Research Institute SA
Bucharest, Romania BOGDAN-VALENTIN PĂUNESCU, Consitrans SA Bucharest,
Romania
Abstract Cellular glass from powders of recycled residual glass,
borax as a fluxing agent, and elm leaves as a bio-foaming agent thermally
treated at over 825ºC by unconventional microwave heating (according to the
own technique) was experimentally manufactured. The wetted mixture was
pressed into a mold and then freely inserted into the inner space of a
ceramic tube of high microwave susceptible materials placed inside the
microwave oven. Ground elm leaves (51 wt. %) were used for the first time as
a bio-foaming agent replacing the much more expensive usual foaming agents.
The results showed that the cellular glass in the optimal variant is
suitable for its application as a heat-insulating building material, having
the apparent density of 0.35 g/cm3, thermal conductivity of 0.074 W/m·K, and
porosity of 83.3%. Due to the choice of using borax (6 wt. %), the
compressive strength of the foam was improved, the 2.5 MPa value of the
optimal variant being only the lowest of the range of 2.5-5.9 MPa achieved
in this experiment. Keywords: cellular glass, residual glass, elm leaf,
borax, microwave heating
Benchmarking on Aloe vera Gel Extraction
ABDOURAMANE NSANGOU, Department of Mechanical Engineering, ENSET,
University of Douala, Cameroon DOINA SIBIESCU, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania,
dsibiesc@tuiasi.ro PIERRE MARCEL
ANICET NOAH, Department of Mechanical Engineering, ENSET, University of
Douala, Cameroon NKEMAJA DYDIMUS EFEZE, HTTTC Bambili-University of
Bamenda, Cameroon FABIEN EBANDA BETENE, Department of Mechanical
Engineering, ENSET, University of Douala, Cameroon BENJAMIN II CASTRO
MPAH EKOUME, Department of Mechanical Engineering, ENSET, University of
Douala, Cameroon VALERY HAMBATÉ GOMDJÉ, Departments of Textile and
Leather Engineering, ENSPM, University of Maroua, Cameroon
Abstract Aloe vera gel is composed of more than 70% saccharide and
polysaccharides is the transparent mucilage contained in the parenchymal
cells of the fresh Aloe vera leaf. This study objective was to produce a
comparison of a set of extraction methods of Aloe vera in the literature.
The methodology used is the synthesis of a set of scientific articles,
theses, dissertations dealing with the issue of Aloe vera gel extraction.
The databases used are (Science Direct, Google Scholar, and ResearchGate).
This work studied 6 types of extractions (traditional extraction, Soxhlet
extraction, Organic solvent extraction, Ultrasonic extraction, Supercritical
extraction and Microwave). These types of extractions were evaluated on
several parameters, namely: extraction principles, solvents, extraction
time, yield, liquid ratio, gel efficiency and number of extractions. The
analysis shows that the quality and yield of Aloe vera gel depends on the
type of extraction it undergoes, organic solvent extraction which are:
yield, which is 20.67 per kg, liquid ratio 1:15, number of extraction 2
times. Although other extraction methods have some information like
traditional extraction the efficiency of gel is poor, the same Aloe vera can
undergo three times traditional extraction then Soxhlet extraction the
efficiency is improved. Ultrasonic extraction has a high efficiency, 98.06%
compared to organic solvent extraction whose yield is 90% and microwave
extraction in ethanol solvent with yield of 80%. Each type of extraction has
its own principle and the solvent to be used. Keywords: Aloe vera gel,
benchmarking, extraction
Evaluation of the Biosorption Performance of Marine Green Algae Biomass
(Ulva lactuca sp.) in the Removal of Inorganic Pollutants
ALINA-ALEXANDRA CIOBANU, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania LOREDANA MUNTEANU, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania GABRIELA VASILE, National
Research and Development Institute for Industrial Ecology, Bucharest,
Romania LAURA BULGARIU, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania,
lbulg@ch.tuiasi.ro
Abstract Contamination of water sources with inorganic pollutants
(cations or anions) is still a serious environmental problem, for which
solutions are still being sought. Therefore, finding a biosorbent that can
retain both cations and anions represent a solution to this problem. In
addition, if such a biosorbent has a low preparation cost, its use in
decontamination processes is recommended. Based on these considerations, in
this study, marine green algae biomass (Ulva lactuca sp.) was used as a
biosorbent for the removal of Cu(II) (inorganic cation) and HPO42-
(inorganic anion) from aqueous media. The experiments were conducted in
batch systems, as a function of initial concentration of each inorganic ion,
at constant pH (6.53), biosorbent dosage (4.0 g·L-1), contact time (1440
min) and temperature (20 ± 2°C). The maximum biosorption capacities obtained
from Langmuir model under these experimental conditions, were 11.44 mg·g-1
for Cu(II) ions and 7.45 mg·g-1 for HPO42- ions, respectively. FTIR
spectrometry, SEM microscopy and potentiometric and conductometric titration
were used for the characterization of the algae biomass. The structural
particularities highlighted by these methods, show that this type of biomass
has functional groups on its surface that can interact both with cations and
anions from aqueous media. Therefore, its use as a biosorbent in
decontamination processes is a viable solution. Keywords: marine green
algae biomass, Ulva lactuca sp., Cu(II) ions, HPO42- ions, biosorption
Methods of Obtaining Magnesium Nanostructured Adsorbent Materials
LUISA MARIA TRIFAȘ, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iaşi, Romania GABRIELA CIOBANU, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania MARIA HARJA, “Gheorghe
Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of
Chemical Engineering and Environmental Protection, Iaşi, Romania,
maria.harja@academic.tuiasi.ro
Abstract Researches in material oxides offers solutions in a variety
of fields including environment, energy production and storage,
biotechnology, medicine and healthcare, electronics, etc. Nanomaterials have
concerned attention in recent decades due to their different enhanced
properties, such as a large surface, particle size, optical or magnetic
properties. To obtain oxide nanomaterials with good performance, the
controlled shape of nanoparticles is very important. This paper outlines few
methods for the preparation of nanoparticles as well as the advantages of
using methods to obtain oxide materials. Conventional methods are still used
in the industrial production of many oxide materials, however there is a
growing demand for alternative routes to green synthesizes of oxide
materials with superior properties. The main current methods of obtaining
nanomaterials in the solid state are the sol-gel method, coprecipitation,
hydrothermal. Keywords: nanomaterials, sol-gel method, precipitation/
co-precipitation method, hydrothermal/solvothermal method
Wastes Used for Obtaining Sustainable Building Materials
MIHAI
VRABIE, S.C. Gemite RO SRL, Iaşi, Romania; “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania MIHAELA CAFTANACHI, S.C.
Gemite RO SRL, Iaşi, Romania; “Gheorghe Asachi” Technical University of
Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection, Iaşi, Romania ALEXANDRU-IOAN COTOFAN, S.C.
Gemite RO SRL, Iaşi, Romania MARIA HARJA, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania,
maria.harja@academic.tuiasi.ro
Abstract Advanced strategies have recently been investigated in
order to decrease the environmental pollution, the danger of depleting raw
material stocks, and increasing pollution following the release of
significant volumes of CO2, resulted by the manufacturing of ordinary
cement. The total or partial substitution of cement with a variety of wastes
or by-products, from other industrial sectors, is one method of utilizing
its to create new building materials. The following wastes can be employed
as raw materials in the formulation of advanced materials based on their
qualities and chemical content: fly ash, silica fume, bottom ash,
phosphogypsum, rice husk ash, red mud, slag, oil fuel ash, etc. For design
the building materials with the requirement properties, wastes and
by-products utilized as raw materials are activated with different reagents.
In this paper wastes from burning processes and few industrial wastes are
presented, with refer to most important properties for obtaining the proper
building materials. Keywords: wastes, fly ash, alkali activated
materials, alkaline solution, slag, silica fume