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Orchid species Anacamptis morio as a potential bioremediator of As, Cd and Pb
No full textIn this study concentration of toxic elements as, Cd, and Pb were determined in different soil types and belonging orchid species Anacamptis morio vital parts, in order to examine accumulation patterns and provide new insights about the potential use of this orchid in bioremediation technology. Soils developed on limestone, serpentine, and the chert were subjected to the BCR sequential extraction. Samples of orchid roots and tubers, as underground parts, and stems, leaves, and inflorescences, as above-ground organs, were also analyzed for the content of as, Cd and Pb. During this research, it was observed that metal content in soil is directly proportional to its content in the plant, more specifically in roots, which suggests that A. morio can potentially be used in the phytostabilization of contaminated sites. Values for BCF factors showed Cd immobilization in roots regardless of the soil type. A certain level of arsenic was transferred from roots to leaves indicating the potential for accumulation of this element into aboveground organs. Assessment of the phytoremediation potential of this orchid or another plant species from diverse environments is important as it provides information about the possibility of their future application in environmental remediation programs
Uklanjanje jona olova iz vodenih rastvora primenom hidročađi komine kupine
No full textU okviru ovog rada ispitan je potencijal hidročađi komine kupine za uklanjane jona olova iz vodenih rastvora. Upoređena je adsorpciona efikasnost materijali dobijenih hidrotermalnom karbonizacijom na različitim temperaturama (20, 240 i 260°S). U cilju poboljšanja adsorpcionih performansi, najefikasnija hidročađje modifikovana primenom 1M rastvora KOH. Preliminarni rezultati su pokazali da modifikovana hidročađ pokazuje višestruko povećanje adsorpcionog kapa- citeta (85,5 mgle) u odnosu na nemodifikovanu (19,5 mg/g). Poznato je da alkalna modifikacija povećava broj kiseoničnih funkcionalnih grupa na površini hidročađi što može biti razlog poboljšanja adsorpcije olova. Rezultati pokazuju da KOH- modifikovana hidročađ kupine može biti razmatrana kao efikasan adsorbens jona
olova
Performances of Vermiculite and Perlite Based Thermal Insulation Lightweight Concretes
No full textThis experimental study was conducted with an aim to investigate the effect of the elevated temperature on the mineral phase composition, microstructure and mechanical properties of the thermal insulation lightweight concretes. The first group of experimental concretes was based on the expanded vermiculite and expanded perlite used as lightweight aggregates (in 65 wt%) in combination with either ordinary Portland cement or refractory calcium aluminate cement. The mix-design of the second group of concretes comprised standard quartz aggregate, vermiculite or perlite as aggregate replacement (25 wt%) and binder (PC or CAC). A total of 10 concrete mix-designs were fabricated in form of 40x40x160 mm samples which were submitted to heat-treatment at 400 degrees, 600 degrees, 800 degrees and 1000 degrees C upon standard 28-days period of curing and hardening. The changes in crystallinity and mineral phase composition induced by temperature were monitored by X-ray diffraction technique. Microstructural visualizations of the non-fired and fired concrete samples were conducted by scanning electron microscopy accompanied with EDX analysis. The results indicated that despite the decrease in compressive strengths upon firing, investigated lightweight concretes can be categorized both as thermal insulators and structural materials
Thermodynamic Aspect of Sodium Carbonate Mechanical Transformations under Different Environment
No full textDuring mechanical activation, the energy of treated material is raised to a higher level that can lead to the chemical transformation of the activated material. This is the point that should be considered as a phenomenon of the mechanochemical transformations appearing as a result of mechanical activation. Sodium carbonate as a substance that is often subjected to mechanochemical synthesis was mechanically activated in this study. The subject was the monitoring of changes in the physico-chemical characteristics of sodium carbonate after exposure to different degrees of activation time within the range of 1-28 minutes. After activation, the samples were deposited in three environments, CO2, air, and vacuum, at room temperature, in a period of 64 days. The mass changes occurring during the treatment were measured depending on the processing environment. Increasing the mass was evident and was attributed to the chemisorption of moisture and carbon dioxide present in the air as a consequence of the sodium carbonate activation. The methods also used were calcimetric chemical analysis and X-ray structural analysis. According to obtained results, it was found that activated sodium carbonate is mass-transformed into sodium bicarbonate, whereby these changes are functionally dependent on activation time and the processing environment
Removal of emerging contaminants from water by zeolite-rich composites: A first approach aiming at diclofenac and ketoprofen
No full textIn this study, composites of the natural zeolites and cationic surfactants cetylpyridinium chloride and Arquad (R) 2HT-75 were used for removal of two emerging contaminants - diclofenac sodium and ketopmfen. Modifying a clinoptilolite- and a phillipsite-rich tuff, with surfactants with one or two hydrophobic tails, resulted in composites in monolayer and bilayer forms. The intention was to better evaluate interactions of composites with selected molecules. Starting materials and composites were characterized by ATR-FTIR and STA coupled with EGA. The adsorption capacities of the prepared sorbents were estimated by determination of adsorption isotherms and kinetic runs. Maximum adsorption capacity, obtained from the Langmuir model, showed that the best results were for the bilayer form of the composites up to 35 mg/g. Between the two surfactants, composites with cetylpyridinium chloride gave better results. Zeta potential measurements showed that the surfactants turned out to be unstable on the zeolite surface, the only exception being bilayers prepared using the two-tailed surfactant Arquad (R) 2HT-75. These results suggested possible applications of these composites for water treatment purposes
Fire-resistant composites based on acrylic-functionalized lignin and polyester resin obtained from waste poly(ethylene terephthalate)
No full textThis paper investigates the using potential of acryl-functionalized kraft lignin (AKL) in reducing the
flammability of polymer composites based on recycled unsaturated polyester resins (UPR). Acryl functionalization of
kraft lignin was performed by direct esterification of free polyphenolic groups with acryloyl chloride, after what, the
AKL was blended in UPR resin synthesized from the polyols obtained by catalytic depolymerization of waste
poly(ethylene terephthalate). The AKL was homogenized in UPR resin in different weight ratios: 2.5, 5.0, 7.5, and 12.5
wt.%. Structural and dynamic-mechanical characteristics of acryl-functionalized kraft lignin and composites were
determined using FTIR spectroscopy, dynamic-mechanical analysis (DMA), and tensile tests. The influence of
functionalization and mass fraction of AKL on tensile and thermal properties of UPR resin was studied. The thermal
properties of the composite were tested according to the standard UL-94 method, based on which the highest category
of heat-resistant materials is a composite with 12.5 wt.% acyl-functionalized lignin
Tehnološka ispitivanja i naučno-stručna validacija rude iz ležišta „Kula“ u cilju proširenja eksploatacionog prostora i uvećanja rudnih rezervi Rudnika „Grot“-Kriva Feja (Vranje)
No full textRudnik olova i cinka GROT AD – Kriva Feja je osnovan krajem 2007. god. Posle privatizacije Rudnika GROT DP, koji je bio pravni sledbenik poznatog Rudnika RO Blagodat – Vranje. Time je GROT AD, kao rudnik pod novim imenom, nasledio znatno duži istorijat, čiji koreni sežu do 1911. kada je rudarsko društvo „Societe commerciale d’Orientale“ iz Milana (Italija) otvorilo rudnik sa separacijom “Mine de Musul”. Prva sistematska geološka istraživanja ležišta Blagodat obavila je RMHK „Trepča” u periodu 1963-67. Rezultat tih istraživanja bile su rudne rezerve A+B+C1 kategorije od 4.8 Mt sa 4.16% Pb i 4.24% Zn. Rudnik GROT AD vrši istraživanje i eksploataciju Pb-Zn rude u eksploatacionom polju Blagodat, koje i danas zadržava značajnu potencijalnost. Eksploataciono polje ima površinu od 11.6 km2 i oblik složenog mnogougla. Eksploataciono polje je prikazano na slici 1. Do 2015. je urađeno sedam geoloških elaborata o rezervama, u ležištu Blagodat (reviri Bare-Đavolja vodenica, Vučkovo i Đ. vodenica II), zaključno sa 2011. overeno je 469.131 t rezervi A+B+C1 kategorije sa 3.95% Pb i 5.61% Zn. Celo rudno polje Blagodat i većina eksploatacionog polja, istočno od razvođa na Besnoj Kobili, pripadaju opštini Bosilegrad, a zapadni deo opštini Vranje. Celokupno područje je izrazito planinsko sa dominantnim grebenom planine Besna Kobila (1923 m) koji je razvođe Crnomorskog i Egejskog sliva
Fabrication and characterization of luminescent Pr3+ doped fluorapatite nanocrystals as bioimaging contrast agents
No full textFluorapatite doped with rare-earth elements has a wide-range of biomedical applications. Here, a new type of fluorapatite nanocrystals doped with praseodymium (FAP-Pr) with excitation-emission profiles in visible part of the spectrum is fabricated. Energy levels of Pr3+ activator ion contain metastable multiples states that offer the possibility of efficient multicolor emission lines in FAP nanocrystals. Three types of FAP-Pr nanocrystals with 0.1%, 0.5% and 1% atomic percent of Pr3+ (along with the undoped FAP control sample) are studied. Their novel chemical production method is described, the FAP-Pr nanocrystals structure, biocompatibility and the suitability for cell imaging are analyzed. Physicochemical characterization confirms crystals down to nanometer size. In addition, quantum-chemical calculation predicts that Pr3+ ions are incorporated into the FAP crystal lattice at Ca2 (6 h) sites. In vitro viability results shows that FAP-Pr nanocrystals are nontoxic to live cells. Additionally, the cell uptake of the FAP-Pr nanocrystals is studied using fluorescence-based widefield and confocal microscopy. The nanocrystals show characteristic green emission at 545 nm (P-3(0)-> H-3(5) transition of Pr3+ ion) and orange emission at 600 nm (D-1(2)-> H-3(4)), which we use to discriminate from cell autofluorescence background. Orthogonal projections across 3D confocal stacks show that the nanocrystals are able to enter the cells positioning themselves within the cytoplasm. Overall, the new FAP-Pr nanocrystals are biocompatible and of the tested types, the 0.5% Pr3+ doped nanocrystals show the highest promise as a tracking nanoparticle probe for bioimaging applications
Waste Slag from Heating Plants as a Partial Replacement for Cement in Mortar and Concrete Production. Part I-Physical-Chemical and Physical-Mechanical Characterization of Slag
No full textNumerous factors influence the complexity of environmental and waste management problems, and the most significant goal is the reuse of materials that have completed their "life cycle" and the reduction in the use of new resources. In order to reduce impact of waste slag on the environment, in the present study, waste slag, generated in heating plants after lignite combustion, was characterized in detail and tested for application as a replacement for cement in mortar or concrete production. For physical-chemical characterization of slag, different experimental and instrumental techniques were used such as chemical composition and determination of the content of heavy metals, investigation of morphological and textural properties, thermal analysis, X-ray, and infrared spectroscopy. Physical-mechanical characterization of slag was also performed and included determination of activity index, water requirement, setting time and soundness. A leaching test was also performed. Presented results show that waste slag may be used in mortar and concrete production as a partial cement replacement, but after additional combustion at 650 degrees C and partial replacement of slag with silica fume in the minimal amount of 12%. The maximal obtained cement replacement was 20% (17.8% slag and 2.2% of silica fume)
Mogućnost razvoja tehnologije prerade bazalta
No full textU radu je ispitivana mogućnost primene bazalta iz ležišta Vrelo - Kopaonik, za dobijanje proizvoda staklo-keramike poboljšanih svojstava za primenu u proizvodnji konstrukcionih elemenata opreme u metalurgiji i rudarstvu. Jedan od ciljeva bio je i proširenje primene ispitivanih keramičkih materijala u inženjerskoj praksi kao zamena za metalne materijale. Istraženi su postupci prečišćavanja, mlevenja I mehaničke aktivacije bazaltnog agregata, postupci sinteze uzoraka procesima presovanja I sinterovanja, kao i procesi topljenja, livenja i termičkog tretmana. S obzirom na rigorozne uslove eksploatacije u metalurškim i rudarskim procesima u cilju ispitivanja kvaliteta i izbora materijala primenjeno je više metoda karakterizacije -rendgenska difrakciona analiza, optička i skenirajuća elektronska mikroskopija, ultrazvučna vibraciona metoda sa stacionarnim uzorkom, kompjuterska analiza slike. Dobra tehnička svojstva čini bazalt važnom sirovinom za primenu u različitim granama industrije. U radu su prikazani i rezultati istraživanja primene bazalta za izradu vatrostalnih premaza za zaštitu metalnih i nemetalnih konstrukcija, kao i ispitivanje primene ojačivača na bazi bazalta u kompozitima tipa polimerna osnova/bazaltni prah za specifične uslove primenu u mašinstvu I građevinarstvu. Srbija raspolaže kvalitetnim bazaltom (stenama bazalta) za istraživanja sinteze novih materijala i široku primenu u industriji. Primena ove vrste sirovina može da doprinese poboljšanju ekonomskih, energetskih i ekoloških aspekata poslovanja metalurških i rudarskih pogona, kao i pogona za reciklažu otpada