Yearly Archives: 2016

Abstract:
Carbohydrate based surfactants represent an alternative to surfactants produced from
petrochemical raw materials. They can be prepared from various renewable vegetable raw
materials in a large structural diversity. This class of surfactants presents high surface active
properties and functionalities, being use in different industrial areas. The development of
carbohydrate based surfactants is possible due to their higher biodegradability and lower
toxicity. Two carbohydrate based surfactants, galactose palmitate and bolaamphiphilic
surfactant 1,12-dodecanedioyl digalactose, were synthesized by reacting the galactose with
fatty acid chlorides, in aqueous medium, alkaline catalysis, at room temperature, following the
principles of green chemistry. The structures of synthesized surfactants were proved by FT-IR
analysis. The surface activity of galactose palmitate was demonstrated by a low surface
tension at the interface water/oil.

Abstract:
Flow cytometry represents an important tool in environmental biology, and especially in cellular
biology, through its ability to distinguish among different physiological states (viable, latent and
non-viable). Flow cytometry combined with fluorescent markers, such as propidium iodide and
ethidium bromide allows to perform rapid measurements on individual cells and also
simultaneous measurements of multiple cellular parameters, both structural and functional.
The aim of this paper was to investigate the influence of the electromagnetic field on the
morpho-physiological parameters of some bacterial strains cells isolated from wastewater,
assessed through flow cytometry. In this respect, a number of 10 bacterial strains isolated from
wastewater (E. coli, Salmonella sp., Enterobacter sp., Citrobacter sp., Klebsiella sp. and
Enterococcus sp.) were exposed to an electromagnetic field (50Hz electric field at different
voltages) for 24 hours, at 37°C. Both samples, the ones exposed to electromagnetic field and
blank samples (unexposed) were assessed by flow cytometry technique. Two possible
mechanism of action have been tracked, i.e. the efflux pumps activity (fluorescence marker Ethidium Bromide) and permeabilisation of cellular layers (fluorescence marker – Propidium
Iodide). Both mechanisms of action have been identified, from slightly to significant
modifications, as compared to untreated controls, quantified as ΔMFI (median of fluorescence
intensity). Conclusion: Our results suggest that flow cytometry could be used for the real-time
evaluation of the influence of different electromagnetic fields on the aquatic microbiota, the
obtained results being of great interest for the development of technological solution with
increased efficiency in the (waste)water treatment.

Abstract:
Membrane Interface Probe – MIP (Geoprobe, USA) is a helpful tool used to detect the presence
of volatile organic compounds (VOCs) with depth in contaminated soil. Dekonta used MIP
technology within several research projects. Further, Dekonta was participating on
development of specially designed injection equipment (MIP-IN) complementary to MIP for
efficient application of remediation agents.

Abstract:
Two surfactants with one hydrophilic head group (lauroyl hydroxyproline and palmitoyl
hydroxyproline) and a bolaamphiphilic surfactant, with two hydrophilic head groups (1,12-
dodecanedioyl diglycylglycine) were synthesized using a method with reduced environmental
impact. The high conversions in useful product were sustained by FTIR analysis. It was
evaluated the surface activity of aqueous solutions of surfactants’ sodium salts and it was
demonstrated a significant reduction in the surface tension compared to distilled water.
Synthesized surfactants can be a viable alternative for the petrochemical products.

Abstract:
2,4,6-Trinitrotoluene(TNT) is one of most common toxic pollutant identified in
wastewater generated from ammunitions plants. Due to its potential carcinogenic
characteristics, TNT presence in water bodies represents a risk for human health and
aquatic life. Among modern treatment methods, TiO2 photocatalysis was successfully
applied in order to remove toxic pollutants. Fe-TiO2 assisted photocatalytic degradation
of TNT in aqueous media, under UV-VIS irradiation was studied. The effects of
operating parameters on photocatalytic process performances, kinetic and mechanism
of pollutant degradation were investigated. Solutions with (0.27-2.72) x 10-4 M TNT
content were photo-oxidized using a medium pressure Hg lamp as UV-VIS light source
(λ = 320 – 550 nm), in the following working conditions: pH = 7; photocatalyst dose =
50 – 500 mg/L; irradiation time = 30 – 240min. Prior to irradiation, the photocatalyst
was added to samples, and resulted suspension was bubbled with air (50 L/h). In order
to evaluate the effect of the main active species involved in Fe-TiO2 assisted
photocatalytic degradation of TNT we suppressed the free •.OH radicals mediated
process by addition of 16 x 10- 3M iso-propanol (i-PrOH) scavenger. Lock of •.OHads
radicals’ production on the catalyst surface was assured by addition of 16 x 10- 3M
sodium iodide (NaI). The initial and irradiated samples were analysed for TNT, NO3-,
NO2- and NH4+ concentrations by Gas Chromatography (GC), and Ion
Chromatography respectively. In the tested experimental conditions, at 2.72 x 10-4 M
pollutant concentration, the increase of catalyst load up to 200 mg/L leads to the
enhancement of initial TNT degradation rate up to 0.64 x 10-7 Ms-1. Since, ten times
increase of initial TNT content has a negative effect on pollutant degradation rate
constant, in similar experimental condition, prolonged irradiation time from 60 to 240
min was needed in order to assure pollutant advanced degradation efficiencies (≥
99.9%). The TNT degradation and its inorganic by-products formation obeyed a
pseudo-first-order kinetics. The experimental results of the reactive species quenching
showed that •.OH radicals was the predominant oxidant species participated in
reaction, and the pollutant degradation occurred mainly on the surface of catalyst.

Abstract:
The wastewater treatment plants are considered to be hotspots for antibiotic resistance
selection, transfer and dissemination. Wastewater offers favorable conditions for the
development of antibiotic resistant bacteria because it contains high amounts of organic
matter, favoring the rapid multiplication of microbial cells and the development of biofilms in
which microbial cells are in close proximity, the presence of pollutants (pesticides, heavy
metals, antibiotics) acting as selective pressure agents for resistance.
The aim of this paper is to investigate how the antibiotics susceptibility profiles of some
microbial strains isolated from wastewater are influenced by electromagnetic fields.
A number of 10 bacterial strains isolated from wastewater (E. coli, Salmonella sp.,
Enterobacter sp., Enterococcus sp., Citrobacter sp., Klebsiella sp.) were exposed to an
electromagnetic field (50Hz electric field at different voltages) for 24 hours, at 37°C. Thereafter,
the antibiotic susceptibility testing was performed for both treated and control strains, by disk
diffusion method, according to CLSI 2016.
The obtained results proved that the electromagnetic field induced in some cases a decrease
of the growth inhibition diameters such as penicillins, cephalosporins, aminoglycosides and
vancomycin, while in other cases an increase of bacterial strains susceptibility to the tested
antibiotics.
These preliminary results demonstrate that the electromagnetic filed in addition with other
selective factors which are present in the wastewaters could modulate the environmental
reservoir of antibiotic resistance and influence the frequency of the selection of resistant
bacteria and the magnitude of the potential risk of dissemination into the environment and of
contamination of animals and humans.