2020, Volume 66(70), Issue 4 (December)
Contents
pages 1- 8 Download
Multiple linear regression (MLR) models used for the prediction of excess thermodynamic properties based on experimental determination of refractive index
IULIANA BÎRGĂUANU, "Gheorghe Asachi" Technical University,
"Cristofor
Simionescu" Faculty of Chemical Engineering and Environmental Protection,
iuliana.birgauanu@yahoo.com
CĂTĂLIN LISA,
"Gheorghe Asachi" Technical
University, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection
SILVIA CURTEANU, "Gheorghe Asachi" Technical
University, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection
GABRIELA LISA, "Gheorghe Asachi" Technical
University, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection
pages 9 - 21 Download
Abstract
In engineering, it is very important to have thorough
knowledge of the thermodynamic and conveying properties of fluid mixtures,
as they are mainly used to study the interactions that occur in fluids with
several components, as well as to design various equipment for separation by
distillation, fractional distillation and solvent extraction, and to achieve
a scientific approach of the risk factors that affect separation processes.
Our research group used the statistical processing of experimental data by
the multiple linear regressions (MLR) method in order to estimate the excess
molar volume starting from the experimental values of the refractive index
for ternary systems. In this paper we will prove that this type of
experimental data processing could also be used to predict other excess
thermodynamic properties such as excess viscosity and excess surface tension
(PE). In order to achieve this goal, we will use both the literature data
and experimental data obtained in our laboratory on the thermodynamic
properties of certain fluid mixtures. The created mathematical models
correlate the excess thermodynamic properties with the refractive index, the
standard temperature and the fluid mixture composition: PE= A0 + A1X1 + A2X0
+ A3(T/298.15) + A4n, where X1 and X2 are the molar fractions, T is the
temperature expressed in Kelvin and n is the refractive index. These models
are extremely useful in practice. The refractive index can be easily
determined, with rather good accuracy and low substance consumption. These
mathematical models also allow the determination of other properties, such
as density, viscosity and surface tension, which are more difficult to
determine by experimental methods.
Keywords: MLR models, density,
viscosity, surface tension, refractive index, multicomponent systems
Stabilization of w/o emulsions using ecofriendly emulsifiers
EMIL IOAN MUREȘAN, "Gheorghe Asachi" Technical University of Iasi,
"Cristofor Simionescu" Faculty of Chemical Engineering and Environmental
Protection, Romania, eimuresan@yahoo.co.uk
ANGELA DĂNILĂ,
"Gheorghe Asachi" Technical University of Iasi, Faculty of Industrial Design
and Business Management, Department of Chemical Engineering, Romania
pages 23 - 30 Download
Abstract
An ecological emulsifier, containing a mixture of fatty acid
esters was prepared by the transesterification reaction of sunflower oil
with ethanol. The reaction was catalysed by CaO resulted from the
calcination of the eggshells. Several emulsions consisting of sunflower oil
and water, which differ from each other by the ratio between phases (70% U /
30% A, 60% U / 40% and 50% U / 50% A) and by the concentration of emulsifier
(2%, 4% and 6% respectively with respect to the vegetable oil mass), were
prepared. The influence of the emulsifier concentration and of the ratio
between phases on the stability of the emulsions were studied. The
microscopic images, the stability index values and the turbidity's values
showed that the most stable is the emulsion containing 60% U / 40% A and 4%
emulsifier.
Keywords: emulsion stability, turbidity, vegetable oil,
eggshell, microscopic image
Natural dye extraction from Pelargonium roseum plants using ultrasound method
DOINA SIBIESCU, "Gheorghe Asachi" Technical University of Iași, România,
"Cristofor Simionescu" Faculty of Chemical Engineering and Environmental
Protection, dsibiesc@ch.tuiasi.ro
MIHAELA VIZITIU,
"Gheorghe Asachi"
Technical University of Iași, România, "Cristofor Simionescu" Faculty of
Chemical Engineering and Environmental Protection
pages 31 - 38 Download
Abstract
Dyes derived from natural sources have been used since
ancient times in households and in various fields. Subsequently, synthetic
dyes were synthesized, but in terms of toxicity, the variant in which the
existence of substances harmful to the environment is not a problem is the
first category. The aim of this paper is to discover a better solid-liquid
extraction technique to avoid the infiltration of dyes found in groundwater
following the discharge of wastewater in which they are contained. A source
of natural dyes is represented by plant materials that are used in plant
research applications, in food, as well as in the paint industries. These
could be Green wattle bark, Marigold flowers, Pomegranate rinds, Pelargonium
roseum, 4’o clock plant flowers, Cocks Comb flowers and more like these. We
used Pelargonium roseum plants. The influence of ultrasound on the
extraction of natural dyes from this material plant as a source of dyes has
been studied in comparison with the process of magnetic stirring. Analytical
studies, such as UV-VIS spectrophotometry and gravimetric analysis, were
performed on the extract. In this regard, the present paper aims at
screening the locally available natural dye yielding plants for dyeing
purpose. The effect of power ultrasound in the extraction of natural dyes
has been studied. Improving the efficiency of dye extraction from plant
materials with 87.5% by using ultrasound has led to the conclusion that this
method is much faster and more efficient than magnetic stirring.
Keywords: Pelargonium roseum, dye solid–liquid extraction, ultrasound
sonochemistry
Biosorbents based on microorganisms
ALEXANDRA CRISTINA BLAGA, "Gheorghe Asachi" Technical University of
Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection
IOANA LUIZA HORCIU, "Gheorghe Asachi" Technical
University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical
Engineering and Environmental Protection
CARMEN ZAHARIA,
"Gheorghe
Asachi" Technical University of Iași, Romania, "Cristofor Simionescu"
Faculty of Chemical Engineering and Environmental Protection
LĂCRĂMIOARA
RUSU, "Vasile Alecsandri" University of Bacău, Faculty of
Engineering
CRISTINA GRIGORAS, "Vasile Alecsandri" University of Bacău,
Faculty of Engineering
DANIELA ȘUTEU, "Gheorghe Asachi" Technical University
of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection,
danasuteu67@yahoo.com
pages 39 - 53 Download
Abstract
Biosorption is a technique used for the removal of not
easily biodegradable pollutants from waters (especially metals and dyes),
that can use a variety of biomaterials with adsorptive properties including
microbial microorganism (algae, bacteria, fungi), but also industrial and
agricultural wastes. The biosorption abilities of microbial biomass towards
dyes and metal ions have been extensively studied, as these biosorbents are
low-cost and ecofriendly materials for water/wastewater treatment
applications, and can be chemically modified, via various techniques, or
genetically engineered to enhance their biosorption capacity. The functional
groups, such as carboxyl, amine and phosphonate of the cell wall
constituents (peptidoglycan, manan, chitin and chitosan), offer increase
biosorption potentials.
Keywords: biosorption, dyes, immobilization,
metals ions, microbial biosorbents, wastewaters
Particle air pollution (PM10) monitoring and public opinion on air quality. A case study in northeastern Romania
BRANIȘTE MIHAELA-VICTORIA, "Gheorghe Asachi" Technical University of
Iași, "Cristofor Simionescu" Faculty of Chemical Engineering and
Environmental Protection, Romania
ȘTEFAN IULIANA, "Gheorghe Asachi"
Technical University of Iași, "Cristofor Simionescu" Faculty of Chemical
Engineering and Environmental Protection, Romania
ANA MELANIA,
"Gheorghe
Asachi" Technical University of Iași, Faculty of Hydrotechnical Engineering,
Geodesy and Environmental Engineering, Romania
UNGA FLORIN, The Cyprus
Institute, Climate & Atmosphere Research Center, Nicosia, Cyprus
MARIUS
MIHAI CAZACU, "Gheorghe Asachi" Technical University of Iasi, Department of
Physics, Romania,
cazacumarius@gmail.com
pages 55 - 67 Download
Abstract
Air pollution continues to be a concern for both the
scientific community and the general population. Promoting pollution events
and the impact they could have on the environment and human health must be
an ongoing challenge. This paper presents a case study on ambient air
quality by monitoring particle concentrations (PM10) in the northeastern
part of Romania. The analysis of a survey on the opinion of the general
population regarding air quality is also presented. The research began with
our concern about the data issued by the WHO (World Health Organization)
which shows that tens of thousands of people are lost, annually, prematurely
due to pollution. Experimental data show that in some areas the
concentration of PM10 is much exceeded. Moreover, in some areas this
concentration is exceeded no less than 82 times in 7 months. At the same
time, the survey shows that people believe they are responsible for the
well-being of the environment but are not sufficiently informed about the
quality of the air they breathe.
Keywords: PM10, air quality, survey
Habilitation thesis summary
Micro- and nanostructured materials with applications in medicine and
environmental protection
MARGARETA GABRIELA CIOBANU, "Gheorghe Asachi" Technical University of Iaşi, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, gciobanu@ch.tuiasi.ro
pages 69 - 72 Download