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Contemporary methods of testing human milk quality
No full textInfant nutrition is essential for their growth and development. This research aims to determine the total antioxidant capacity of the infant food for preterm infants and indicate adequate methods for testing the quality and biological value of milk and infant food. The total antioxidant capacity (TAC) was determined in human milk and an infant formula for premature infants. The determination of the total antioxidant capacity was made using cyclic and differential pulse voltammetry, potentiometry and electron paramagnetic resonance spectroscopy. The results of three comparative electrochemical methods indicate that human milk has a higher antioxidant potential compared to infant formula, which contributes to better physiological development of the child. Fenton-based electron paramagnetic resonance spectroscopy method provides additional insight into TAC analysis, whereby a carbon-centered radical and an ascorbyl radical are formed in infant food. All methods can be used to determine TAC, since the results obtained individually with each method follow the same trend
Essential and toxic elements content in the medicinal plant Capsella bursa-pastoris (L.) Medic. and its extracts
No full textDue to its anti-inflammatory and antibacterial properties, Capsella bursa-pastoris (L.)
Medic., has been considered a medicinal plant, and hence, it is frequently used for teas and
tincture preparation. In this research, samples of this medicinal plant were collected in
Belgrade, Bor, Vršac, and Sremska Mitrovica in Serbia, during the spring of 2021. This
study assessed the levels of toxic and essential elements accumulated in theabove-ground
parts of a plant, and herbal infusions, and ethanolic extracts prepared of same aerial parts
of plant. The concentration of elements: As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Zn, S,
P, Mg, K, and Ca was determined by inductively coupled plasma optical emission
spectroscopy (ICP-OES). Translocation factors were calculated for each sampling site,
followed by correlation analysis, in order to investigate elements distribution and
extraction levels
Modified lignin-based microspheres as a green sorbent for the removal of chromium ions
No full textThe unique chemical structure of lignin shows the possibility of its application as a basic material for
the sorption of various pollutants from water. In this paper, the newly synthesized porous lignin-based
material was used to remove Cr(VI) ions. Modified lignin microspheres (LMS) were synthesized by the
process of inverse copolymerization of kraft lignin with poly (ethylene-imine), and amino modified
iron oxide (magnetite) using epoxy-functionalized cross-linker. The shape of obtained adsorption
material was partially spherical to spherical. The functionalization was performed to improve the
pollutant removal capacity. Structural and surface characteristics of the LMS microspheres were
characterized by Brunauer-Emmett-Teller method (BET), Fourier transform infrared spectroscopy
(FTIR), scanning electron microscopy (SEM) and point of zero charge pH (pHPZC). The maximum
adsorption capacity for oxyanion Cr(VI) was 77.024 mg g-1obtained by Langmuir adsorption isotherm
at 35°C. Based on kinetic studies, the adsorption process follows a pseudo second-order model.
Thermodynamic parameters have shown that the adsorption process is endothermic and spontaneous.
LMS is an environmentally friendly, cost-effective and therefore promising adsorbent for the removal
of Cr(VI) with efficient adsorption and reusability
Limestone processing – problems
No full textLimestone is a versatile commodity used to create products for ag-ricultural, environmental, and industrial purposes. Cement, paint, soil amend-ments, and even breakfast cereals all contain this resourceful mineral. Of course, mined limestone is not naturally found in a suitable form for many of these products. Therefore, various processing systems are needed to transform raw limestone rock material into a useful product. Common limestone processing methods that prepare the material for subsequent manufacturing stages include drying, calcining, pre-conditioning, and pelletization. The following information highlights limestone processing issues associated with these techniques, as well as general material challenges associated with limestone manufacturing
X-Ray diffraction analysis of mechanically activated natural zeolite
No full textIn this research, preliminary investigations of the influence of mechanical energy during the
milling process on a sample of natural zeolite were performed. Activation was performed in a
mill with a ceramic vessel and ceramic balls for 15, 30 and 60 minutes. The XRD method was
used to determine the phase composition. The XRD patterns were obtained on a Philips PW-
1710 automated diffractometer using a Cu tube operated at 40 kV and 30 mA. All the XRD
measurements were performed at room temperature in a stationary sample holder. Crystallite
domain size were calcuclated using SiroQuant v4 software. The mineral composition of the analyzed sample is as follows: clinoptilolite-heulandite zeolite types, smectite/chlorite
minerals, quartz, feldspars, mica, and irregularly interstratified clay minerals. Crystallinity
degree of all present phases decreases with activation time in comparison to the non-activated
sample. Crystallite domain size for diffration maximum (020) of non-activated sample was
533 Å (FWHM 0.240 o), and decreases with acitivation time to 202 Å (FWHM 0.275 o) for
sample activated 60 min
Potential of rangeland species Festuca valesiaca for phytoremediation of contaminated sites: case study of copper mine Bor, Serbia
No full textMetalliferous mine wastes are notable sources of contamination remaining after ore
exploitation process. Bor mine is one of the largest copper mine basins in Europe where longterm
mining caused severe degradation and environmental pollution, making it one of the
remediation priorities in the country. Mine wastes, formed by non-selective overburden
deposition, generated surface Technosols of variable physico-chemical conditions. Moreover,
they are characterized by increased concentration of potentially toxic elements, such as As,
Cu, Pb, and Zn.
Festuca valesiaca Schleich. ex Gaudin, species characteristic for rangelands of
Eurasia, was found colonizing dry sandy patches of Bor mine waste Technosols. Parent
material was fresh andesite and conglomerates rocks of volcanic origin. This research aims at
revealing the potential of F. valesiaca for phytoremediation of such multi-contaminated sites.
Composite rizosphere soil and plant material were collected and analyzed from several
selected sites. Soil pH was measured in 1 to 2.5 ratio of soil and distilled water using pHmeter.
Organic carbon content was determined by the method of Tjurin, while total nitrogen
content was obtained by Kjeldahl digestion process. Pseudo-total and bioavailable
concentration of As, Cu, Pb, and Zn were determined in soil samples by using aqua-regia and
EDTA-extraction, respectively. Underground and aboveground parts of F.valesiaca were
digested with HNO3 and H2O2. Concentration of elements in soil and plant material was
analyzed using ICP-OES (Thermo Scientific, 6500 Duo). Bioconcentration (BCF), bioaccumulation (BAF) and transfer factors (TF) were determined for pseudo-total and
EDTA-available soil fractions.
Technosols colonized by F. valesiaca were alkaline (pH=7.23-8.35), with low organic
matter (0.85-2.5%) and total nitrogen content (0.03-0.05 %). Pseudo-total contents of As, Cu,
Pb and Zn were 137 mg kg-1, 1152 mg kg-1, 113 mg kg-1and 221 mg kg-1, respectively.
Bioavailable fractions ranged from 4.75% (As) to 36.2% (Pb) of their pseudo-total content.
Estimated BCF for Cu was highest, exhibiting values 1.12, while in the case of bioavailable
Cu fractions it was 6.52. Generally, BCFEDTA values were >1 for all investigated elements.
While all BAF factors were 1 (1.05, 1.14 and
5.87, respectively). Root to shoot ratios were low, ranging from 0.18 (Cu) to 0.41 (As).
F. valesiaca showed phytostabilization potential in case of pseudo-total Cu content at
Bor mine waste site. Moreover, it also exhibited possibility for accumulating all investigated
trace elements in roots in relation to their bioavailable concentration. As this is palatable
species, low transfer of elements from root to shoot enables safe use of F. valesiaca for
phytostabilization of copper mine wastes in Bor, but potentially also for other similar multipolluted
sites within its wide distribution range
Upgrading fuel potentials of waste biomass via hydrothermal carbonization (vol 75, pg 297, 2021)
No full textThe application of pine-based adsorbents to remove potentially toxic elements from aqueous solutions
No full textBased on the concept of circular economy and green chemistry, the conversion of wastes into high added value products should be of great importance. From this point of view, this review chapter summarizes the application of pine-based adsorbents obtained from pine bark, pine cone and pine needles, to adsorb heavy metals, radionuclides, rare earths, and others from aqueous media. Effect of various parameters such as pH, temperature, and contact time is critically presented and discussed in detail. The adsorption capacities, fitted https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotherm and kinetic models, as well as thermodynamic aspects, are also included in the discussion. The present compilation reveals that generally the experimental data are better fitted by the Langmuir isotherm and pseudo-second-order kinetic models and the adsorption is a spontaneous process. From this literature survey, it is evident that pine-based adsorbents have interesting adsorption properties and could be attractive candidates as adsorbents for inorganic pollutants removal from (waste)water
Crystal growth of La(2)SrB(10)O(19)from undercooled melt
No full textThe crystal growth rate of La(2)SrB(10)O(19)in an undercooled melt of stoichiometric composition was studied. The crystallization of the bulk samples was performed in a single-stage regime under isothermal conditions at the selected temperatures for the different time periods. The surface crystallization was observed and in all crystallized samples, the La(2)SrB(10)O(19)crystalline phase was identified. Based on the dependence of the crystalline layer thickness on treatment time at selected temperature, crystal growth rate was obtained. The crystal growth rates were from 1.65 x 10(-8)to 2.77 x 10(-7)m s(-1)in the temperature interval (700-780 degrees C). The experimental values were compared to the calculated values using theoretical model of the crystal growth. The experimental growth rate followed the same trend as the calculated growth rate, but the experimental values were higher than the calculated
Mechanisms of alachlor and pentachlorobenzene adsorption on biochar and hydrochar originating from Miscanthus giganteus and sugar beet shreds
No full textThis work investigates the adsorption mechanism of alachlor and pentachlorobenzene on chars (hydrochars and biochars) originated from Miscanthus giganteus and sugar beet shreds. Two different processes were used: hydrothermal conversion at three temperatures (180, 200, and 220 degrees C) and slow pyrolysis at 400 degrees C. Specific surface area (SSA) for all investigated chars ranged 3.87-260 m(2)/g, whereby biochars had a higher SSA. For hydrochars from sugar beet shreds, both the SSA (3.87-5.53 m(2)/g) and pore volume (0.023-0.0277 cm(3)/g) increased with increasing temperature, while the opposite trend was observed for hydrochars from miscanthus. The opposite trend could be a consequence of the different chemical composition of the used feedstock such as hemicelluloses and cellulose which can produce volatile organic products at higher temperatures and may cause the reduction of SSA. All adsorption isotherms were well described by the Freundlich model. The nonlinearity of the isotherms ranged from 0.450 to 0.986. K-d values for both investigated compounds followed the order: hydrochars from sugar beet shred LT hydrochars from miscanthus LT biochars, implying that the SSA of the chars affects the adsorption mechanism. In general, all the investigated adsorbents demonstrated higher adsorption affinity for pentachlorobenzene in comparison with alachlor, implying that hydrophobic interactions enhanced the adsorption of the more hydrophobic organic compound. In addition, for all hydrochars, adsorption affinities for the smaller pentachlorobenzene are significantly greater than for the larger alachlor, probably due to its ability to better penetrate into the pores of the adsorbents. This type of research is necessary to obtain safe adsorbents for water remediation