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Evaluation of acute toxicological profile of the selected natural clays in rats
No full textNatural bentonite (NBNT) and natural halloysite (NHAL), as clay minerals, are used in animal nutrition because their absorption/adsorption properties contribute significantly to animals' health [1]. Clay minerals have also emerged special attention as potential materials for biomedical applications, due to their favorable physicochemical and functional related characteristics along with good biocompatibility. Since it has been proved natural clays have their toxicologcal profiles, and that any modification can change this profile, we evaluated acute toxicology on selected materials
Thermal characterization of bioactive polyphosphate glass with strontium addition
No full textPolyphosphate glasses are a class of bioactive glasses that have gained significant attention in recent years due to their unique properties and potential applications in various fields, particularly in the area of biomedical engineering. These glasses exhibit excellent biocompatibility, which is a crucial requirement for biomaterials. Furthermore, their dissolution and degradation rates can be tailored by modifying their composition, allowing for control over their bioactivity and biodegradability. Polyphosphate glasses also have the ability to form a hydroxyapatite-like layer on their surface when in contact with biological fluids, which facilitates their integration with surrounding tissues. The unique properties of polyphosphate glasses make them promising candidates for various biomedical applications, including bone tissue engineering, drug delivery, and wound healing. This paper presents the thermal characterization of two bioactive polyphosphate glass compositions with the addition of strontium, to investigate the sintering and crystallization processes. The samples were synthesized using the melt-quenching method and then sintered at various temperatures. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to analyze the thermal behavior and crystalline phases formed during sintering. Our results showed that sintering and crystallization are separate processes for both compositions. The addition of strontium to the glass improved its sintering behavior, resulting in a denser glass structure. Moreover, strontium incorporation did not affect the formation of the crystalline phase during sintering. These findings provide useful insights into the design and development of bioactive polyphosphate glass compositions for bone tissue engineering applications
X-ray structural analysis of the BaO and TiO2 starting compounds and initial mechanochemical activation
No full textThe aim of this research was to obtain an initial characterization
of the BaO and TiO2
components, as well as to conduct preliminary
research into the possibility of activating the initial components in order to
obtain barium titanate. Chemical and X-ray structural analysis of the initial
components was performed. In order to determine the possibility of
applying a mechanochemical activator and the activation time in which the
first intermediate compounds were formed by the activation of the starting
substances, the system was activated for 30 minutes. After this, an X-ray
structural analysis was performed and certain changes in the crystal lattice
of the starting components were made. X-ray structural analysis showed that during grinding, amorphization of the initial components occurred,
which is the first stage in the process of obtaining titanate, as well as the
presence of a small amount of barium titanate, which is indicating the
presence of an intermediate compound in the process of finally obtaining
barium titanate
Improving Thermoelectric Properties of p-type (BiSb)2(TeSe)3 Single Crystal by Zr Doping
No full textIn order to study the effect of Zr doping on the thermoelectric properties of p-type Bi10.17Sb30.72 Zr0.35Te58.28Se0.48 single crystal, аn ingot was prepared by Bridgman method. Cut and cleaved samples from different regions of ingot were characterized by a Hall Effect based on the Van der Pauw method. The first measurements were conducted with four ohmic contacts at room temperature and the obtained results were presented in our investigation, earlier. Аlso, high charge carriers mobility was obtained on the sample with silver contacts at the temperature of liquid nitrogen. Single crystal was characterized by Seebeck coefficient (S), conductivity (κ) and resistivity (ρ) measurements as а function of temperature in the range of 40-320°C by a home-made impedance meter. The prepared single crystal has a figure of merit (Z) of 1.22 x 10-3 K-1 at 300°C.У циљу проучавања утицаја допирања Zr на термоелектричне особине монокристала Bi10.17Sb30.72 Zr0.35Te58.28Se0.48 п-типа, припремљен је ингот Бриџмановом методом. Сечени и цепани узорци из различитих делова ингота испитивани су Холовим ефектом заснованим на Ван дер Пауовој методи. Прва мерења су спроведена са четири омска контакта на собној температури и добијени резултати су представљени у нашим истраживањима раније. Такође, добијена је висока покретљивост носиоца наелектрисања и на узорку са сребрним контактима на температури течног азота. Монокристал је испитиван мерењима Зебековог коефицијента (S), мерењима проводљивости (κ) и отпорности (ρ) у опсегу температуре од 40-320°C мерачем импедансе домаће израде. Добијени монокристал има вредност фактора квалитета (Z) од 1.22x10-3 K-1 на 300°C
Removal of heavy metal ions from multimetallic solution by modified oat straw
No full textIn this paper, the ability of waste biomass as an adsorbent was investigated. Oat straw was chosen as the starting raw material. In order to improve the adsorption capacity this material was modified with selected deep eutectic solvent (DES). Changes in the structure of the native and modified samples were examined using the SEM analysis. The efficiency of the adsorption of heavy metal ions from a multimetal solution was tested on the modified oat straw. The maximum obtained capacities of lead, copper and zinc ions were 77mg/g, 29.5mg/g and 44.1mg/g, respectively. The obtained results showed that adsorption follows pseudo-second-order kinetics model that imply chemisorption as a rate controlling step
Improvement of energy properties of lignocellulosic waste by thermochemical conversion into biochar
No full textPeach stones, a valuable agro-industrial by-product available in many countries worldwide,
comprise a renewable resource, which can be widely applied for multifunctional purposes.
Its important advantages such as high-energy value, low ash content, low price and wide
abundance, make peach stones an ideal fuel for energy production, but also for new
materials synthesis. Although peach stones exhibit adequate combustion properties,
allowing their direct use with minimal physical/chemical treatment, they often need further
modification in order to improve their thermal properties, where slow pyrolysis is frequently
used. This study aims to provide a practical and effective solution to the revalorization of
waste biomass originating from the fruit processing industry, through slow pyrolysis in order
to convert this waste into carbonaceous material – biochar. The thermo-chemical conversion
of raw biomass resulted in a stable material with excellent fuel properties, with higher mass
energy density and grinding ability, providing biochar with properties, in energy sense,
similar or even better than a coal. Biochar has a higher fixed carbon content and a higher
energy potential than biomass itself, and its application as a biofuel might reduce emissions
of greenhouse gases, as it reduces the amount of waste landed and increases the share of
energy generated from renewable sources.Koštice breskve, otpadna biomasa poreklom iz industrije prerade voća, dostupna u mnogim zemljama širom sveta, predstavlja obnovljivi resurs koji može imati različitu primenu. Prednosti koje se ogledaju u velikom energetskom potencijalu, malom sadržaju pepela, niskoj ceni i širokoj rasprostranjenosti, čine koštice breskve idealnim resursom za proizvodnju energije, ali i za sintezu novih materijala. Iako koštice breskve imaju svojstva koja im omogućavaju da se koriste uz minimalni fizičkio-hemijski tretman, često im je potrebna dodatna modifikacija kako bi se poboljšala njihova svojstva. Jedan on načina poboljšanja energetskih karakteristika otpadne biomase predstavlja termohemijska konverzija materijala u vidu spore pirolize. Ispitivanja prikazana u ovom radu obavljena su sa ciljem obezbeđivanja praktičnog i efikasnog rešenje za revalorizaciju otpadne biomase koja potiče iz industrije prerade voća, putem spore pirolize kojom se vrši konverzija ovog otpada u ugljenični materijal – biočađ. Prikazani rezultati ukazuju na glavna svojstva dobijene biočađi u funkciji njene primene kao čvrstog goriva, istovremeno ih upoređujući sa svojstvima sirove biomase. Termohemijska konverzija polazne lignocelulozne biomase daje stabilni ugljenični material odličnih gorivih karakteristika, veće energetske gustine i boljih mehaničkih svojstava, što rezultuje energetskim svojstvima koja su bolja od uglja. Biočađ poseduje znatno veći energetski potencijal od same biomase, i njegova primena kao biogoriva može redukovati emisiju gasova sa efektom staklene baste, pri čemu se istovremeno smanjuje količina deponovanog otpada ali i povećava udeo energije generisane iz obnovljivih izvora
The application of biochar onto soils-benefit for overall environment
No full textBiochar-stable, solid, carbon rich material has gained interest in the last decades as a versatile material for waste reduction whose applications in various fields can increase the efficacy of the circular economy. Biochar has demonstrated possibilities in the field of reducing negative environmental impact of different process, positive effects on climate change and sustainable energy support. All of this is connected to the biochar’s intrinsic properties, impacted by certain variables such as feedstock type, pyrolysis conditions, materials modifications etc. Biochar and its application onto soil is a typical example on how waste resources are upcycled to make a material which can be further used towards environment improvement. This paper describes some of the possible uses of biochar, with special accent paid on its beneficial application onto the soil
Luminescence transitions of Pr3+ (4f2) in fluorapatite nanocrystals for potential biomedical application
No full textFluorapatite (FAP) crystals have drawn significant interest over the last few decades as important hosts matrix for optically active trivalent rare earth ions, due to the strong crystal field splitting and large transition cross-sections. Nano-sized FAP particles doped with rare earth ions have been extensively studied as luminescent materials for biomedical applications for cell labeling and bioimaging, as well as antimicrobial agents for therapeutics.
Fluorapatite nanoparticles doped with praseodymium ions (Pr3+) were prepared by the co precipitation method and characterized. The different number of Pr3+ (4f2) transitions in the ultraviolet and visible parts of the spectrum was investigated by photoluminescence spectroscopy. Multivariate Curve Resolution–Alternating Least Squares (MCR-ALS) analyses of fluorescence spectra and ab initio calculation indicated that Pr3+ ions are
preferentially substituted Ca2 (6h) sites in FAP lattice. In addition to the substitution of cations, there is also the substitution of anionic species such as OH-, CO32-, and NO3-, which are confirmed by the CHNS method. The obtained samples were tested as bioimaging and
antibacterial agents and can potentially be used for further biomedical research
Innovative industrial symbiosis approach for acidic mine drainage neutralization
No full textFollowing the principles of sustainable development and circular economy, an innovative industrial symbiosis approach
has been developed that uses already disposed voluminous waste. The research was focused on the utilization potential
of vast amounts of flotation tailings, fly ash and acidic mine waters. Numerous previous case studies have pointed out the
harmful, long-lasting environmental damage from waste disposal. In this case, the emphasis is on finding a practical
approach for using industrial waste, specifically thermal power plant fly ash, in order to neutralize acidic mine waters
resulting from tailings disposal. The proposed treatment gives waste a practical value, eliminates its harmful effect on the
environment and redefines (lowers) regular waste management costs. In addition, it is possible to obtain valuable metals
by exploiting and reprocessing acidic mine drainage
Testing of grinding media performances at the conditions of Pb-Zn smelting slag wet milling and prediction of balls consumption by ann-based models
No full textThis paper describes a part of the experimental procedure for testing the performance of grinding media (steel balls) during the smelting slag milling, as well as the modeling procedure and model results that predict the consumption of balls under given experimental conditions. Firstly, the most suitable mineral raw material for testing the durability of the grinding media was defined. In laboratory conditions, it was determined that it is most expedient to use slag from the melting process of Pb-Zn concentrate for testing. The coarse moisture content was determined on the initial slag sample, while the particle size composition and Bond work index were determined on the crushed slag samples. In accordance with the characteristics of the raw material, the technical-technological parameters of the system for wet grinding of slag were defined, in which the balls durability test was performed. The obtained results showed that the consumption of grinding media is about 1 kg/t of slag. Six ANN models, developed on the basis of experimental results, showed good predictive abilities when it comes to stel balls consumption. As a result of modeling, high correlation coefficients were obtained, the value of which was about R = 0.99