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Biomass waste material as potential adsorbent for sequestering pollutants
No full textKonvencionalne tehnologije za uklanjanje polutatanata iz životne sredine nisu ekonomski isplative i uglavnom generišu velike količine hemijski toksičnih muljeva. Biosorpcija se promoviše kao potencijalno alternativna tehnologija u odnosu na konvencionalne, zasnovana na primeni ekonomski prihvatljivih bioloških mateirjala koje odlikuje niska cena, visoka efikasnost, obnovljivost, minimiziran hemijski i biološki otpad, regeneracija biosorbenata sa mogućnošću izdvajanja metala. U radu su prikazani neki rezultati ispitivanja efikasnosti koščica breskve, poreklom iz 'Vino Župa' Aleksandrovac, kao agroindustrijskog otpada i urbanog otpada, vodene biljke, Miriophillum spicatum, iz veštačkog Savskog jezera u Beogradu, kao jeftinih biosorbenata za uklanjanje teških metala (Cu, Pb), uranijuma kao radionuklida i mikotoksina iz vodenih rastvora. Zemlje u razvoju poput Srbije, koje imaju velike količine otpadne biomase, biosorpcione tehnologije otvaraju mogućnost razvijanja efikasnih i jeftinih adsorbenata za uklanjanje različitih tipova polutanata sa perspektivom otvaranja novih tržišta.Conventional treatment technologies for the removal pollutants from the environment usually aren’t economically viable or may further generate huge quantity of toxic chemical sludge which requires further treatment. Biosorption is emerging as a potential alternative technique to the existing conventional technologies; its application is economically acceptable because it reuse biological materials with their major advantages: low cost, high efficiency, renewability, minimization of chemical or biological sludge, easy regeneration of biosorbents and possibility of metal recovery. The paper presents the review of the results of the biosorption efficiency of two biosorbents: peach shell, originating from 'Vino Župa' Company from Aleksandrovac, as agro-industrial waste and urban waste, aquatic plant, Myriophyllum spicatum, harvested from artificial Sava Lake, Belgrade, as low cost biosorbents for removal of several pollution type: heavy metal ions (Cu, Pb), uranium as radionuclide and mycotoxins. Biosorption treatment method is especially applicable in developing countries where a 'low cost tech' approach may be a suitable option
Synthesis and sintering of high-temperature composites based on mechanically activated fly ash
No full textKoličina letećeg pepela koji se proizvodi i koja će biti proizvedena u godinama koje dolaze zahteva razvoj novih metoda recikliranja u kojima će biti upotrebljene značajne količine ovog otpadnog materijala. Mogućnost visoko-temperaturne aplikacije (termoizolacioni i vatrostalni materijali) ukazuje na novu mogućnost za primenu letećeg pepela. Za takvu primenu leteći pepeo mora da zadovolji visoke mehaničke i termičke kriterijume. Jedan od načina da se to postigne je mehanička aktivacija letećeg pepela. U ovom radu prikazani su rezultati mehaničke aktivacije pepela iz dve različite termo-elektrane pomoću planetarnog mlina. Aktivirani pepeli su mešani sa dva veziva: portland cementom i visoko-aluminatnim cementom. Akcenat je na analizi fizičko-hemijskih svojstava i mineroloških faza zbog promena koje se dešavaju u kompozitima usled mehaničke aktivacije pepela i sinterovanja. Makro svojstva kompozita su povezana sa mikrostrukturom ispitivanom pomoću SEM analize i Rendgenske difrakcije. Termijska stabilnost kristalnih faza ispitivana je pomoću DTA. Akcenat je na utvrđivanju korelacija između mehaničke aktivacije letećeg pepela i mikrostrukture kompozita na jednoj i svojstava sinterovanog kompozita na drugoj strani.Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side
Examination of phosphate ores bioleaching from Lisina deposit
No full textPostupci rastvaranja fosfora iz nerastvornih fosfatnih ruda pomoću acidofilnih autotrofa i heterotrofa spadaju u veoma bitna istraživanja, zbog moguće primene ovih ruda kao đubriva, čija je upotreba ekonomski i ekološki prihvatljivija od industrijskih fosfatnih đubriva. Predmet ovog rada je bio da se ispita mogućnost rastvaranja fosfora iz fosfatne rude sa ležišta Lisina (Bosilegrad), u laboratorijskim uslovima, dejstvom sumporne kiseline generisane pomoću bakterijske kulture Acidithiobacillus (At.) ferrooxidans, izolovane i selekcionisane sa jalovišta površinskog kopa rudnika bakra u Boru. Cilj eksperimenta je da se utvrdi da li je moguće rudu sa navedenog ležišta u kombinaciji sa ispitivanom bakterijskom kulturom koristiti kao prirodno đubrivo. Dobijeni rezultati pokazuju da se tokom eksperimenta rastvara fosfor iz ispitivane rude pod uticajem At. ferrooxidans i da je stepen rastvaranja 24,5 %, dok je rastvaranje fosfora u kontrolnoj suspenziji (bez At. ferrooxidans) iznosilo 7,2 %. Uticaj At. ferrooxidans na rastvaranje fosfora je potvrđen, tako da dalja istraživanja treba usmeriti na ispitivanja mikrobiološkog luženja mešavina apatita sa sulfidnim supstratima, zbog eventualne primene vezane za poboljšanje kvaliteta alkalnih zemljišta.Phosphorus solubilization from insoluble phosphate ores by acidophilic autotrophs and heterotrophs is a research of significant interest, because of potential use of these ores as fertilizers, which are economically and ecologically more acceptable than industrial phosphate fertilizers. The object of this paper was to examine the possibility of phosphorus leaching from phosphate ore from Lisina deposit (Bosilegrad), by bacterially generated sulfuric acid, in laboratory conditions. The experiments were carried out with bacterium Acidithiobacillus (At.) ferrooxidans, which is isolated and selected from the copper sulphide mine in Bor. The main goal of the experiment was to confirm if it is possible to use phosphate ore in combination with examined bacterial culture, as a natural fertilizer. Results obtained show that phosphorus has been leached up to 24,5 % in suspension with At. ferrooxidans, and in the same time, degree of leaching in control suspension (without At. frrooxidans) was up to 7,2 %. Influence of At. ferrooxidans on phosphorus solubilization has been confirmed, so the future perspective of our investigations should be directed to examination of microbiological leaching of apatite mixtures with sulphide substrates, and their potential use in quality improvement of alkaline soils
Application of controlled release glass in the production of French marigold (Tagetes patula L.)
No full textU radu je ispitivana mogućnost i opravdanost primene stakla sa kontrolisanim otpuštanjem hranljivih elemenata kao novog ekološkog materijala u proizvodnji biljaka-rasada kadifice (Tagetes patula L.). Tokom istraživanja praćen je njegov uticaj na razvijenost proizvedenih biljaka-rasada. Biljke-rasada proizvedene su u polistirenskim kontejnerima (speedling system) i polipropilenskim saksijama (pot system). Istraživanja su sprovedena u stakleniku Poljoprivrednog fakulteta u Beogradu tokom 2011. U toku proizvodnje rasada dodavano je ispitivano staklo granulacije LT 0,5 mm u dozama 0-4 g/l. Rezultati istraživanja ukazuju na pozitivan efekat primenjenog stakla sa kontrolisanim otpuštanjem jona u proizvodnji biljaka-rasada kadifice. Njegovom primenom dobija se rasad bolje razvijenosti, te je njegova upotreba opravdana. Najbolji efekat na ispitivane parametre razvijenosti biljaka-rasada imala je doza od 1 g/l supstrata.This paper investigates the possibility and justification of controlled release glass application as a new ecological material in the production of plants-seedlings of French marigold (Tagetes patula L.). During the investigation its influence on the development of the produced plants-seedlings was monitored. The seedlings were produced in poly-propylene containers (speedling system) and poly-propylene pots (pot system). The trial was conducted in the greenhouse at the Faculty of Agriculture in Belgrade during 2011. In the course of seedling production the glass granulation of LT 0.5 mm was added in the following doses: 0, 1, 2, 3, and 4 g/l. The results of the research show a positive effect of controlled release glass application in the production of French marigold seedlings, since high quality seedlings were produced justifying its application. The best effect on the analyzed parameters of plant-seedling development was found when substrate was applied in the dose of 1 g/l
Crystallization behaviour of multicomponent germanate glasses
No full textPredmet ove doktorske disertacije je ispitivanje kristalizacionog ponašanja germanatnih i germanatnofosfatnih stakala iz sistema K2O-Nb2O5-GeO2 i Li2O-Al2O3- GeO2-P2O5. Na osnovu preliminarnih ispitivanja za proučavanje su izabrana stakla sastava: 30K2O·34Nb2O5·36GeO2 (mol%) i 22,5Li2O·10Al2O3·30GeO2·37,5P2O5 (mol%). Kristalizacione osobine ispitane su pri izotermskim i neizotermskim uslovima kristalizacije. Dobijeni rezultati pokazuju da trokomponentno germanatno staklo kristališe primarnom kristalizacijom, pri čemu fazni sastav kristalisanog uzorka kao i nastajanje pojedinih kristalnih faza zavise od temperature kristalizacije. Na temperaturama kristalizacije LT 800 °C kao primarna faza javlja se K3.8Nb5Ge3O20.4, a kao sekundarne faze javljaju se K4Nb6O17 i K6Nb6Ge4O26. Na temperaturama kristalizacije > 800 °C kao primarna faza javlja se K6Nb6Ge4O26, a kao sekundarne faze javljaju se: K3.8Nb5Ge3O20.4, K10Nb22Ge4O68 i KNbO3 faza. Dimenzije kristalita su 20-100 nm. U slučaju četvorokomponentnog germanatnofosfatnog stakla utvrñena je primarna kristalizacija LiGe2[PO4]3 faze sa dimenzijama kristalita 30-500 nm. Odreñen je uticaj granulacije praha stakla na mehanizam kristalizacije i fazni sastav kristalisanih uzoraka. U slučaju kompaktnih uzoraka stakla konstatovan je zapremiski mehanizam kristalizacije sa sferulitskom morfologijom rasta kristala kod oba sastava. Ispitan je proces nukleacije i odreñena je temperaturna i vremenska zavisnost brzine nukleacije. Brzine nukleacije ovih stakala su u oblasti 1,77·1014 - 7,34·1016 m-3s-1 . Odreñena je temperaturna zavisnost brzina rasta kristala i energije aktivacije koje iznose od 294 kJ/mol do 1150 kJ/mol u zavisnosti od faze koja se formira. Odreñene su oblasti nukleacije i rasta kristala, temperature maksimalne brzine nukleacije i procenjene temperature maksimalne brzine rasta kristala. Konstatovano je preklapanje oblasti nukleacije i rasta kristala kod oba sastava. U ispitivanjima su korišćene metode atomske apsorpcione (emisione) spektrometrije (AAS), spektrofotometrije, dilatometrije, diferencijalno-termijske analize (DTA), diferencijalno-skenirajuće kalorimetrije (DSC), infracrvene spektroskopije (FT-IC), rendgenske difrakcione (XRD) i skenirajuće elektronsko mikroskopske (SEM) analize...The subject of this thesis is the study of the crystallization behavior of germanate and germano-phosphate glasses from the systems K2O-Nb2O5-GeO2 and Li2O-Al2O3-GeO2- P2O5. Based on preliminary experiments the glasses of composition 30K2O·34Nb2O5·36GeO2 (mol%) and 22,5Li2O·10Al2O3·30GeO2·37,5P2O5 (mol%) were selected for examination. The crystallization properties were examined under isothermal and non-isothermal crystallization conditions. Three-component germanate glass crystallize by primary crystallization while the phase composition of crystallized sample and formation of the crystalline phases depends on temperature of crystallization. At crystallization temperatures LT 800°C as the primary phase K3.8Nb5Ge3O20.4, appeared and as seconday ones are K4Nb6O17 and K6Nb6Ge4O26. For T > 800 °C, the K6Nb6Ge4O26 appeared as primary phase and as secondary ones are K3.8Nb5Ge3O20.4, K10Nb22Ge4O68 and KNbO3. In the case of four-component germano-phosphate glass the primary crystallization of LiGe2[PO4]3 phase with crystallites dimension of 30-500 nm was detected. The effect of the grain size of glass powders on crystallization mechanism and phase composition of the crystallized samples was determined. For both glass compositions the volume crystallization mechanism with a spherulitic growth morphology of crystals was determined on compact glass samples. The nucleation process was studied and the temperature and time dependencies of nucleation rate were defined. The nucleation rate of these glasses are in the range 1,77·1014 - 7,34×1016 m-3s-1 . Also, the temperature dependence of crystal growth rate was determined and the activation energies calculated are 294 - 1150 kJ/mol depending on the phase formed. The temperature ranges of nucleation and crystal growth and the temperature of maximal nucleation rate and the temperatures of maximal crystal growth rates were determined. For both glass compositions, an overlapping of nucleation and crystal growth range was noted. The methods employed for investigation are: atomic absorption spectroscopy (AAS), spectrophotometry, dilatometry, differential thermal analysis (DTA), differential scanning calorimetry (DSC), infra reed spectroscopy (FTIR), X- ray diffraction (XRD) and scanning electron microscopy (SEM)..
Current methods for recovering metals from electronic waste
No full textKontinuirani informatički razvoj za posledicu ima stalni rast u proizvodnji čvrstog otpada. Elektronski otpad je deo univerzuma zastarelih i / ili oštećenih uređaja i komponenata koje treba na kraju njihovog životnog ciklusa na ekološki ispravan način odložiti, odnosno što je ekološki prihvatljivije - reciklirati. U ovom radu razmatrani su različiti hemijski postupci - korišćeni ili predloženi - za dobijanje metala iz elektronskog otpada, dostupni u literaturi i njihove prednosti i nedostatci. Svi navedeni postupci uključuju sledeće procese: pirometalurgiju, hidrometalurgiju, elektrohemiju i biotehnologiju (poslednje spomenuti proces neće biti predmet razmatranja u ovom radu). Dalji razvoj postojećih tehnologija ponovnog dobijanja metala iz elektronskog otpada usmerava se ka razvoju procesa sa većom efikasnošću, strogoj kontroli efluenata i emisija, primeni netoksičnih reagenasa uz mogućnost njihove maksimalne reciklabilnosti, smanjenju utroška energije - na ekonomski i ekološki siguran način.The continuous IT development has resulted in steady growth in solid waste production. Electronic scrap is a part of the universe of obsolete and/or defective equipment and components that need to be disposed or, ecologically more appropriate, to be recycled, at the end of their life cycle. This paper considers various chemical processes - used or proposed - for obtaining metals from electronic waste, available in the literature and their advantages and disadvantages. All listed procedures include following processes: pyrometallurgy, hydrometallurgy, electrochemistry and biotechnology (the last mentioned process will not be considered in this paper). Further development of recovering metals technologies from electronic waste is directed towards the process development with greater efficiency, strict control of effluents and emissions, implementation of non-toxic reagents, with the possibility of their maximum recyclability, reduced energy consumption - in an economically and environmentally safe manner
Sustainable development and environmental protection
No full textKoncept održivog razvoja je relativno novi koncept koji je uveden s ciljem da se prevaziđu nedostaci prethodnih modela razvoja; pre svega, zapostavljanje pitanja zaštite životne sredine. Održivi razvoj teži uspostavljanju ravnoteže među različitim dimenzijama razvoja: ekonomskom, ekološkom i socijalnom. Ipak, uprkos širokom korišćenju ovog pojma, neophodno je bolje razumevanje pojma održivosti kako bi se olakšala primena ovog modela razvoja. Uzimajući ovo u obzir, u radu se daje pregled različitih interpretacija i značenja diskursa održivosti, s naglaskom na odnosu između koncepta održivog razvoja i pitanja zaštite životne sredine.Sustainable development is a recently developed concept that was introduced in order to overcome the shortcomings of previous forms of development; first of all, the neglect of environmental issues. Sustainable development aims to establish an equilibrium among economic, environmental and social dimensions of development. Yet, despite an extensive use of this term, it needs better understanding in order to make easier its implementation. Taking this into account, this paper reviews various interpretations and meanings of the sustainable development discourse, focusing on the relation between sustainability and environmental protection issues
Rare element mineralization in northern part of the Srebrenica Orefield, Podrinje metallogenic district, Eastern Bosnia
No full textU polimetaličnim rudama srebrničkog rudnog polja, koje je deo podrinjske metalogenetske oblasti, a koja pripada Srpsko-Makedonskoj metalogenetskoj provinciji (SMMP), javlja se u većem obimu specifična mineralizacija, sa pojavama minerala Sn, Ti i retkih zemalja. Minerali Sn i Ti dominiraju nad ostalim retkim mineralima. Oni su vezani za intenzivne silifikacije na kontaktu paleozojskih škriljaca i magmatita dacit-andezitskog sastava (severni rudni revir). Određeno je nekoliko različitih mineralnih parageneza, koje su se formirale pre glavnog produktivnog stadijuma Fe-Pb-Zn-Sb mineralnih asocijacija. Takođe, pojedini retki minerali su analizirani pomoću elektronske mikrosonde, čime je potvrđeno kompleksno obrazovanje mineralizacija. Rudno polje Srebrenice izdvaja se od ostalih iz SMMP, i približava bolivijskim mineralnim asocijacijama. .In polymetallic ores of the Srebrenica orefield, which is a part of the Podrinje Metallogenic District and further the Serbo-Macedonian Metallogenic Province (SMMP), greisen with mineralizations of tin, titanium and REE minerals occur. Tin and titanium minerals are dominant over other rare minerals. They are connected to intensive silification onto contacts of Paleozoic slates and intrusions of dacite-andesite composition (North ore zone). Several different mineral parageneses are determined, which were formed before main productive stadium of Fe-Pb-Zn-Sb mineral associations. Furthermore, some rare minerals were analyzed using Electron Microprobe, and confirmed complex formation of mineralization. Srebrenica orefield is distinguished from all other of the SMMP and is very close to Bolivian mineral associations.
The efficiency of in vitro adsorption of mycotoxins by adsorbents of plant origin
No full textThe paper describes in vitro model for evaluation of ability of two adsorbents of plant origin, to adsorb different mycotoxins. Fresh harvested tissues of submerged aquatic plant Myriophyllum spicatum, obtained from Sava lake - Belgrade, was washed with HCl solution (3%) and then with distilled water. Plant material was afterwards dried for few days at room temperature, then for 6 hours at 50°C, crushed and sifted. Peach stones, obtained from "Vino Župa" - Aleksandrovac, were separated from soft fruit residues, washed, dried at room temperature, crushed and separated from kernels. The peach stones were further used as milled shell fractions. A total of six mycotoxins: aflatoxin B1 (AFL), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZON), diacetoxyscirpenol (DAS) and T-2 toxin were tested in vitro. For adsorption experiments crude extracts of mycotoxins were used. The ability for binding mycotoxins was evaluated in the electrolyte 0.1 M K2HPO4 (pH 3.0 and 6.9, respectively). Mass ratio of individual mycotoxin and natural mineral adsorbent was 1:5000. The experimental mixtures were incubated for 1 hour on a rotary shaker (185 rpm) at room temperature (22-25°C). The extractions of nonadsorbed mycotoxins from the filtrates were performed with organic solvents, and their quantifications were done by thin-layer chromatography. M. spicatum bound more (94.7-96.0%) of applied AFL B1 than peach stones (73.3-80.0%). In the case of OTA higher adsorption indexes were observed by peach stones (50.0-66.7%). Binding of DON has been observed only by peach stones. Its adsorption index varied from 25.0 to 50.0% depending on the pH of the used electrolyte. M. spicatum adsorbed more ZON at pH 6.9 while peach stones adsorbed more ZON at pH 3.0. In the case of type A trichothecenes (DAS and T-2 toxin) adsorbents of plant origin bound only T-2 toxin. The amount of adsorbed T-2 toxin ranged from 16.7 (pH 3.0) to 33.33% (pH 6.9)
Investigation of phase equilibria and characterization of alloys in the Bi-Cu-Ni system
No full textFazne ravnoteže u Bi-Cu-Ni ternarnom sistemu proucavane su eksperimentalnim metodama (SEM-EDS, DTA i DSC), kao i analiticki primenom CALPHAD metode. Proracun ravnotežnih faznih dijagrama u Bi-Cu-Ni sistemu izveden je na osnovu optimiziranih termodinamickih parametara za sastavne binarne sisteme i dodatnih termodinamickih parametara, odredenih u ovom radu. Proracunati fazni dijagrami izotermalnih preseka na 300oC, 400oC i 500oC uporedeni su sa eksperimentalnim rezultatima iz literature i ustanovljeno je dobro medusobno slaganje. Definisani su ternarni termodinamicki parametri za tecnu fazu, i BiNi fazu u kojima je uzeta u obzir eksperimentalno potvrdena rastvorljivost bakra u BiNi fazi. Proracunati fazni dijagrami tri vertikalna preseka uporedeni su sa DTA/DSC rezultatima iz ovog rada. Odredene su tvrdoca i elektricna provodljivost kao dopunska karakterizacija legura ispitivanog Bi-Cu-Ni ternarnog sistema.Phase equilibria in the Bi-Cu-Ni ternary system have been studied experimentally using SEM-EDS, DTA and DSC methods, and analytically using CALPHAD method. Calculation of equilibrium phase diagrams of Bi-Cu-Ni system was performed using optimized thermodynamic parameters of the constituent binary systems and additional thermodynamic parameters determined in this study. Calculated isothermal sections at 300oC, 400oC and 500oC were compared with experimental results from the literature and good agreement is found. Ternary thermodynamic parameters for the liquid phase were determined, as well as for the BiNi phase, in which the experimental confirmation of copper solubility in BiNi phase was taken into account. Three calculated vertical sections were compared with the DTA/DSC results from this work. Hardness and electrical conductivity as an additional characterization of the investigated alloys of Bi-Cu-Ni ternary system were determined