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Korozijai ir karščiui atsparaus plieno standaus apkrovimo ciklinių deformavimo parametrų nustatymas / Evaluation of cyclic properties by static characterristics for structural materialsKopūstienė, Diana 13 June 2005 (has links)
It is impossible to improve the quality of the machines, to increase their reliability and lifetime if the working conditions and the properties of the material are not analyzed. We must know the type of the material (hardening, softening or cyclically stabile), what is chosen for the constructions in low cycle loading, because strain and stress change during the exploitation and depend on this type. If we know the type of the material, we can determine the possibility of its application in concrete exploitation conditions. Real working conditions of the most constructions are close to loading with limited strain (hard straining), because elastic and plastic deformation is met in the zones of crack and stress concentration, that are surrounded with elastically deformed material.
The low cycle loading curves parameters A, and are used for the computation of elastic plastic strain curves. These parameters are obtained from the soft low cycle loading results in many cases. The other possible ways for the determination of parameters A, and are shown in this work.
The most investigated materials had the initial instability in the interval . For more objective evaluation of stress strain curves parameters A, and , all values of width of hysteresis loop up to semicycle were rejected as insignificant in comparison with the rest lifetime in cycles range . The parameter for the evaluation of hardening (softening) intensity was determined, when the values of... [to full text]
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Arsenic stabilization in step-wise amended soil / Pakopinė arseno stabilizacija užterštame dirvožemyjeVaičikauskaitė, Alfreda 01 June 2011 (has links)
This master thesis was performed in order to investigate arsenic stabilization in step-wise amended soil. Object of the work - soil which taken from the former wood impregnation industrial site in Forsmo, Sweden. It is contaminated with chromate-zinc-arsenate (CZA). Method of the work - three different amendments were used: zerovalent iron (Fe), fly-ash (FA) and peat (P). The test was performed in three weeks. During the first week, four mixtures (with each single additive and with all together) and blank soil was observed. During the second and third weeks test was performed step-wise adding amendments to soil+Fe mixture. Moisture was kept constant all the time. After each week extractions were made and later investigated by doing electrical conductivity, redox potential and pH tests. For elemental composition ICP-OES analysis was performed. The results of the work - the best result to stabilize arsenic were achieved by adding single iron. Stabilisation using iron, fly-ashes and peat elevated As leaching compared to non-amended soil. Step-wise amendment did not have a significant difference from single amelioration neither to arsenic, nor to other heavy metals investigated. / Darbo tikslas - įvertinti pakopinės stabilizacijos poveikį arseno bei kitų sunkiųjų metalų (SM) judrumui užterštame dirvožemyje. Darbo objektas - chromuotu cinko arsenatu užterštas dirvožemis, paimtas iš buvusios medienos apdirbimo aikštelės Forsmo vietovėje, Švedijoje. Darbo metodika - tyrimui buvo naudoti trejopi priedai: geležis (0), lakieji pelenai ir durpės. Tyrimas atliktas per tris savaites. Pirmosios savaitės metu buvo stebimi keturi dirvožemio ir jo priedų mišiniai bei kontrolinis dirvožemio mėginys. Vėliau dirvožemio ir geležies mišinys buvo pakopiniu būdu papildomas lakiaisiais pelenaisi ir durpėmis. Iš visų mišinių padarytos ištraukos ir jose matuojamas elektrinis laidumas, oksidacijos-redukcijos potencialas, pH; atlikta elementinė analizė. Darbo rezultatai - efektyviausiai arseną stabilizuoja geležis. Stabilizacija, naudojant lakiuosius pelenus ir durpes, padidino arseno išsiplovimą iš dirvožemio, lyginant su kontroliniu dirvožemio mėginiu. Pakopinė stabilizacija nebuvo efektyvesnė už vienkartinę stabilizaciją nei arseno, nei kitų tirtų sunkiųjų metalų atžvilgiu.
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Uticaj promene fizičko-hemijskih uslova i odabranih tretmana na mobilnost metala u sistemu sediment/voda / The impact of changes in physical-chemical conditions and selected treatments on the mobility of metals in sediment / water systemsKrčmar Dejan 08 October 2010 (has links)
<p>U radu je ispitana distribucija metala u sistemu sediment/voda na najugroženijim vodotocima u<br />AP Vojvodini. Na osnovu dobivenih podataka urađena je procena rizika na osnovu analize<br />porne vode, kiselog volatilnog sulfida i simultano ekstrahovanih metala i sekvencijalne<br />ekstrakcione procedure. Procena mobilnosti metala u sistemu sediment/voda određena je<br />promenom fizičko-hemijskih uslova u realnom sistemu (vodotok) i u laboratorijskim uslovima.<br />Ispitana je efikasnost in-situ (aeracijom sistema sediment/voda) i ex-situ remedijacije<br />sedimenta metodama termičkog tretmana i solidifikacije/stabilizacije.<br />Rezultati su ukazali da u svakom vodotoku i zaštićenoj zoni postoji lokacija u kojoj je sediment<br />barem po jednom metalu klasifikovan (holandski sistem klasifikacije sedimenata) kao zagađen<br />(klasa 3) ili izuzetno zagađen sediment (klasa 4). Generalno, kvalitet sedimenta manjih<br />vodotoka (Krivaja, Nadela, Kudoš, Veliki Bački kanal i Begej) je lošiji u odnosu na ostale<br />ispitivane vodotoke.<br />Procena dostupnosti metala u sedimentu Velikog Bačkog kanala ukazala je da na svakom<br />ispitivanom profilu postoji minimum jedan metal i jedna metoda koja definiše sediment kao<br />visoko rizičan. Takođe je zaključeno da je sediment na delu od 2+000 do 4+900 km zagađeniji,<br />jer postoji veći broj metala i metoda koji ga definišu kao visoko rizičnim. Ovako dobijeni<br />rezultati ukazuju da nije dovoljan jednostavan i samo jedan pristup u oceni kvaliteta sedimenta<br />i proceni rizika koji metali mogu da ispolje u akvatičnom ekosistemu.<br />Ukazano je da pomeranje sedimenta (npr. otvaranja ustave), dovodi do promene fizičkohemijskih<br />uslova u sistemu sediment/voda, resuspenzije i transporta sedimenta. Usled ovih<br />promena povećava se dostupnost metala i dolazi do povećanja njihove koncentracije u vodenoj<br />fazi čime se znatno povećava rizik i mogućnost ispoljavanja negativnih efekata na akvatični<br />ekosistem.<br />U slučaju resuspenzije sedimenta u sistemu sediment/voda pronađena je zavisnost između<br />koncentracije metala u suspendovanim materijama i vodi od sadržaja određenih frakcija u<br />suspendovanim materijama (sadržaj organskih materija i frakcije do 63 μm).<br />Remedijacione tehnike često su ekonomski neprihvatljive zbog velike zapremine zagađenog<br />sedimenta. Ukazano je da primena in-situ aeracije, omogućava smanjenje količine sedimenta<br />(čime se smanjuju troškovi eventualno naknadnog tretmana sedimenta), a da je tretman<br />solidifikacije/stabilizacije sedimenta sa glinom i termičke remedijacije zadovoljavjući sa<br />aspekta izluživanja metala. Dobijeni rezultati izvedenih testova izluživanja ukazali su na<br />moguću primenu ovih tretmana u pogledu rešavanja problema sedimenta koji je zagađen<br />metalima, bilo u pogledu sigurnog odlaganja na deponiju ili u smislu njegove upotrebe kao<br />dodatka pri proizvodnji građevinskog materijala (opeke), osnove za puteve, uređenje obale<br />(nasipa) itd. Na taj način mogu se znatno umanjiti troškovi izmuljivanja i manipulacije<br />kontaminiranog sedimenta, a sama remedijacija učiniti mnogo prihvatljivijom</p> / <p> This work investigates the distribution of metals in the sediment / water systems of the most<br /> endangered rivers in Vojvodina. Utilizing the data obtained, risk assessments are carried out<br /> based on analysis of pore water, acidic volatile sulphides and simultaneously extracted metals<br /> and sequential extraction procedure. The assessment of metal mobility in the sediment / water<br /> system is determined by the changing physical and chemical conditions in real systems<br /> (waterways) and under laboratory conditions. The effectiveness of in-situ (aeration of sediment<br /> / water) and ex-situ remediation of sediment by thermal treatment methods and solidification /<br /> stabilization are investigated.<br /> The results show that in each waterbody and protected area, certain locations have sediment<br /> which for at least one metal, is classified (by the Dutch system of sediment classification ) as<br /> polluted (class 3) or highly polluted (class 4). In general, the quality of sediment in smaller<br /> rivers (Krivaja, Nadela, Kudoš, Veliki Bački canal and Begej) is inferior to the other rivers<br /> studied.<br /> Assessment of the metals availability in the sediments of the Veliki Bački canal indicates that<br /> in each profile examined, at least one metal and one method defines the sediment as very<br /> hazardous. It is also shown that the sediment at the section from 2 +000 to 4 +900 km is the<br /> most polluted, with a number of metals and methods that define it as a high risk. The results<br /> indicate that it is inadequate to have a simple singular approach to sediment quality assessment<br /> and the assessment of the risks posed by metals detected in aquatic ecosystems.<br /> This work shows that sediment movement (e.g. from opening a sluice gate) leads to changes in<br /> the physical-chemical conditions of the sediment / water system, with resuspension and<br /> sediment transport. These changes increase metals availability and increase their<br /> concentrations in the aqueous phase, significantly increasing the posed risk and the possibility<br /> of adverse effects on aquatic ecosystems.<br /> In the case of sediment resuspension in the sediment / water system, a relationship was found<br /> between the concentration of metals in suspended matter and the concentration in the water for<br /> certain fractions of suspended matter (organic matter content and the fraction up to 63 μm).<br /> Remediation techniques are often not economically viable due to the large volume of<br /> contaminated sediments involved. It is shown that the implementation of in-situ aeration<br /> reduces the amount of sediment (which reduces the costs of subsequent sediment treatment),<br /> and that solidification / stabilization treatment with clay and thermal remediation results in<br /> satisfactory remediation with respect to metals leaching. Leaching test results show the<br /> potential of these treatments to solve the problem of sediments which are contaminated with<br /> metals, either in terms of safe disposal in landfill or in terms of its use as a supplement in the<br /> production of building materials (brick), as road foundation, or for river bank reinforcement<br /> (dams), etc.. Thus, the costs of dredging and manipulating contaminated sediments can be<br /> significantly reduced, making remediation itself much more applicable.</p>
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Procena potencijala remedijacije sedimenta primenom imobilizacionih agenasa / Assessment of potential remediation of metal contaminated sediment using imobilisation agentsDalmacija Milena 28 June 2010 (has links)
<p>Predmet izučavanja ove disertacije je ispitivanje mogućnosti imobilizacije toksičnih metala u sedimentu primenom imobilizacione tehnike solidifikacije/stabilizacije portland cementom, kalcijum-oksidom, prirodnim zeolitom, letećim pepelom, kaolinitom, montmorilonitom, i različitim smešama ovih agenasa kao i određivanje njihove efikasnosti u zavisnosti od brojnih faktora. Efikasnost imobilizacionih postupaka praćena je korišćenjem tzv. testova izluživanja, odnosno određivanjem koncentracije metala koji su u toku određenog vremena iz imobilisane faze prešli u mobilnu fazu gde se smatraju potencijalno opasnim i biodostupnim. Krajnji cilj svakog testa izluživanja je mogućnost procene adekvatnosti primene određene imobilizacione, odnosno remedijacione tehnike. Efikasnost imobilizacionih postupaka zavisi i od određenih osobina: pH rastvora, dodatka imobilizacionog agensa što je istraživanjem ispitano. Na osnovu ovog testa, odnosno odnosa kumulativne frakcije metala koja je oslobođena iz imobilizacione smeše u mobilnu fazu i vremena određen je tip mehanizma koji omogućava transport metala (spiranje, difuzija, rastvaranje). Takođe su određeni i i parametri (koeficijenti difuzije, indeksi izlužljivosti) koji će poslužiti za ocenu efikasnosti prethodno primenjenih imobilizacionih tehnika. Primenjeni su i modifikovani testovi izluživanja sa ciljem što bolje simulacije realnih uslova. U modifikovanim testovima izluživanja korišćen je rastvor sa pH 3,25 da bi se simulirali uslovi koji oponašaju kisele kiše, odnosno uslovi u realnom sistemu. Takođe je koršćen i rastvor huminskih materija sa ciljem simulacije uslova velikog organskog opterećenja do kojeg bi moglo doći u slučaju akcidentnih situacija (na primer poplava) i generalno uslova koji se stvaraju u prirodi pri raspadanju organskog materijala (lišće, trava, itd.). Rezultati dobijeni simulacijom ovih uslova će dalje omogućiti modelovanje ponašanja metala u smislu dugoročnog "izluživanja" iz tretiranog sedimenta kao i procenu najefikasnijih agenasa za imobilizaciju različitih metala u sedimentu. Na osnovu dobijenih rezultata, zaključeno je da su optimalni agensi za imobilizaciju metala u sedimentu smeša cementa i kreča (5% cementa i 10% kreča), smeša montmorilonita i kreča (30% montmorilonita i 10% kreča), leteći pepeo (30%) i zeolit (30%). U ovim smešama dominantan mehanizam izluživanja je difuzija, a ove smeše se mogu smatrati inertnim otpadom po svim ispitivanim kriterijumima. Ovi rezultati se mogu upotrebiti za projektovanje i izgradnju pilot postrojenja na kome bi se ispitala efikasnost ovih agenasa za remedijaciju sedimenta u realnim uslovima. Dobijeni podaci su neprocenjivi sa aspekta ekonomski i ekološki prihvatljivog upravljanja sedimentom.</p> / <p>This work is concerned with exploring the possibilities of immobilization of toxic metals in sediments using solidification/stabilization as imobilization technique and using Portland cement, calcium oxide, natural zeolite, flying ash, kaolinite, montmorilonite, and various mixtures of these agents and determine their effectiveness depending on many factors. Performance of imobilization procedures was followed by the use of so-called leaching tests and determination of the metals concentration that are within a specified interval of time leached from the immobile phase and as such can be considered potentially hazardous and bioavailable. The ultimate goal of every leaching test is to assess the adequacy of the possibility of applying certain imobilization or remediation technique. Performance of imobilizaction procedures depends on certain characteristics: pH of solution, additon of imobilization agent, etc. Based on this test, ie relation between the cumulative fraction of metal leached from imobilization mixture and time, the type of leaching mechanism that allows the transport of metals (wash-off, diffusion, dissolution) was determined. Other parameters which will serve for evaluating the efficiency of the previously applied imobilization techniques (diffusion coefficients, leaching indices) were also determined. Modified leaching tests were applied with the aim of better simulation of real conditions on the field. In the modified leaching tests the solution with pH 3.25 was used to simulate conditions that mimic acid rain and conditions in the real system. The humic acid solution was also used with the aim to simulate high organic loads which could occur in the case accident situation (eg floods) and the general conditions that are created in naturewhen decaying organic material (leaves, grass, etc.). The results obtained by simulating these conditions will enable the modeling of behavior of metals in terms of long-term leaching period from the treated sediment and assess the most effective agents for the immobilization of various metals in the sediments. Based on these results, it was concluded that the optimal agents for immobilization of metals in the sediment mixture of cement and lime (5% cement and 10% lime), a mixture montmorilonite and lime (30% montmorilonite and 10% lime), fly ash (30%) and zeolite (30%). In these mixtures dominant leaching mechanism is diffusion, and these mixtures can be considered as inert waste by all tested criteria. These results can be used to design and builda pilot plant in which order to evaluate the effectiveness of these agents for remediation of sediment in real terms. The obtained data are invaluable from the aspect of economic and ecologically acceptable management of sediment.</p>
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Primena stabilizovanog nano nula valentnog gvožđa i komercijalnih imobilizacionih agenasa za remedijaciju sedimenta kontaminiranog toksičnim metalima / Application of stabilized nano zero valent iron and commercial immobilisation agents for remediation of sediment contaminated with toxic metalsTomašević Dragana 03 October 2013 (has links)
<p>Predmet istraživanja ove disertacije je mogućnost korišćenja nano nula<br />valentnog gvožđa stabilizovanog sa bentonitom, kaolinitom i karboksimetil<br />celulozom za imobilizaciju teških metala, kao i ponašanje i sudbina metala u<br />sedimentu. Istraživanja je usmero u dva pravca: prvi deo istraživanja ima za cilj,<br />pre svega da definiše bolje razumevanje ponašanja metala u sedimentu i<br />određivanje njihove potencijalne mobilnost, biodostupnost i potencijalne<br />toksičnost na osnovu metoda sekvencijalne ekstrakcione procedure, kiselo<br />volatilnog sulfida i simultano ekstrahovanih metalau netretiranim i tretiranim<br />uzorcima sedimenta. Takođe, određena je efikasnosti korišćenja nanomaterijala<br />za imobilizaciju metala u sedimentu iz tretiranih smeša korišćenjem tzv. testova<br />„izluživanja“ kao i definisanje dominantnog mehanizma izluživanja koji<br />omogućava transport metala. Drugi deo istraživanja ima za cilj ispitivanje<br />mogućnosti primene nano nula valentnog gvožđa obloženog sa bentonitom,<br />kaolinitom i karboksimetilcelulozom za tretman zagađenog sedimenta na lokaciji<br />(in-situ), uz određivanje potencijalnog rizika po okolinu na osnovu rezultata<br />sekvencijlane ekstrakcione procedure i ekstrakcija u jednom koraku nakon<br />tretmana. Primenjeni su i modifikovani testovi izluživanja sa ciljem što bolje<br />simulacije realnih uslova. Rezultati dobijeni simulacijom ovih uslova i daljom<br />karakterizacijom smeša, kako sa nanomaterijalom tako i smeša sa glinom,<br />omogućuju izradu modela ponašanja metala u smislu dugoročnog "izluživanja" iz<br />tretiranog (stabilizovanog) sedimenta kao i procenukoji materijali su efikasniji<br />za imobilizaciju toksičnih metala u sedimentu.</p> / <p>This thesis explores the possibility of using nano zero valent iron stabilized with<br />bentonite, kaolinite, and carboxymethyl cellulose for the immobilization of heavy<br />metals, as well as the behaviour and fate of metalsin sediments. Research is focused<br />in two directions: the first part of the study aimsto find a better understanding of the<br />behaviour of metals in sediments and to determine their potential mobility,<br />bioavailability and potential toxicity based on sequential extraction procedures and<br />acid volatile sulphides and simultaneously extracted metals methods, in untreated and<br />treated sediment samples. The efficacy of using nanomaterials for the immobilization<br />of metals in sediments is also determined, by applying "leaching" tests to the treated<br />mixtures and defining the dominant leaching mechanism that enables the transport of<br />metals. The second part of the study aims to examine the possibilities of applying<br />nano zero valent iron coated with bentonite, kaolinite and carboxymethyl cellulose for<br />the treatment of contaminated sediment in-situ, to determine the potential risk posed<br />to the environment after treatment, based on the results of sequential extraction<br />procedures and a single step extraction. Modified leaching tests were applied in order<br />to achieve better simulation of real conditions. The results of simulating these<br />conditions and further characterization of mixtureswith both nanomaterials and clay,<br />provide a long term "leaching" model for the behaviour of metals in the treated<br />(stabilized) sediments, as well as assessing which materials are most effective for the<br />immobilization of toxic metals in sediments.</p>
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Potencijal upotrebe piritne izgoretine u tretmanu otpadnih voda i mogućnost njene dalje sanacije primenom imobilizacionih agenasa / Potential use of pyrite cinders in wastewater treatment and the possibility of its further disposal by using imobilizacionih agentsKerkez Djurdja 17 October 2014 (has links)
<p>Predmet izučavanja ove disertacije bio je ispitivanje mogućnosti korišćenja piritne izgoretine u tretmanu otpadnih voda tekstilne industrije kao i dalji tretman mulja nastalog nakon ovog procesa. Naime, nakon iskorišćenja ovog otpada u Fenton procesima, iskorišćena piritna izgoretina u najvećem procentu čini mulj koji zaostaje nakon tretmana. Kako se piritna ruda još u procesu proizvodnje sumporne kiseline koristi neprečišćena, zaostali mulj koji je potencijalno toksičan i ne može se direktno odlagati bez prethodnog tretmana. Stoga, primenjena je tehnika stabilizacija i solidifikacija (S/S) uz korišćenje portland cementa, kalcijum-oksida, prirodnog zeolita, letećeg pepela, kaolinita, bentonita i autohtone gline za imobilizaciju metala. Istraživanja u ovoj disertaciji vršena su u dve faze. Prva faza imala je za cilj optimizaciju operativnih uslova Fenton tretmana pri kojima se postiže najviši stepen obezbojavanja i mineralizacije ispitivanih efluenata. Takođe ispitivanje je uključilo i karakterizaciju nastalih efluenata kako bi se procenila efikasnost primenjenog, i mogućnost daljeg tretmana. Druga faza uključivala je karakterizaciju nastalog mulja nakon tretmana obojenih efluenata i njegov tretman solidifikacijom i stabilizacijom. Vršeno je određivanje efikasnosti primenjenih imobilizacionih agenasa u S/S tretmanu i dominantnog mehanizma <br />izluživanja metala koji opisuju njihov transport iz dobijenih solidifikata. Primenjeni su i modifikovani testovi izluživanja sa ciljem što bolje simulacije realnih uslova. Rezultati dobijeni simulacijom uslova će dalje omogućiti modelovanje ponašanja metala u smislu dugoročnog "izluživanja" iz tretiranog otpada kao i procenu najefikasnijih agenasa za imobilizaciju različitih metala u ovom tipu otpada. TakoĎe primenjeni su testovi izluživanja sa jednom ekstrakcijom kako bi se osiguralo slaganje rezultata sa maksimalno dozvoljenim koncentracijama aktuelnih pravilnika. Na osnovu dobijenih rezultata zaključeno je da se piritna izgoretina može uspešno koristiti kao izvor katalitičkog gvožđa u Fenton tretmanima obojenih efluenata i može se smatrati efektivnom metodom predtretmana za nebiodegradabilne otpadne vode, čineći ih pogodnijim za konvencionalni biološki tretman. Takođe u drugoj fazi istraživanja, na osnovu dobijenih rezultata, zaključeno je da je mulj tertian sa navedenim imobilizacionim agensima uspešno solidifikovan i stabilizovan materijal. Optimalane su smeše koje kao jedan od imobilizacionih agenasa sadrže leteći <br />pepeo, prevashodno u kombinaciji sa cementom i krečom. Dobijeni podaci su neprocenjivi sa aspekta ekonomski i ekološki prihvatljivog upravljanja opasnim industrijskim otpadom. </p> / <p>This work is concerned with exploring the possibility of using pyrite cinders in the treatment of textile industry effluents and further treatment of sludge generated after this process. Namely, after the utilization of this waste in Fenton processes slag that remains after treatment is mostly composed of used pyrite cinder. As the pyrite ore, in the production of sulfuric acid, is used untreated, sludge that remains is potentially toxic and cannot be disposed directly without treatment. Therefore, the stabilization and solidification (S/S) technique with the usage of portland cement, calcium oxide, zeolite, fly ash, kaolinite, bentonite and native clay was used for metal immobilization. The research in this dissertation was carried out in two phases. The first phase aimed to optimize the operational conditions of Fenton treatment in which the highest degree of decolourization and mineralization was achieved in tested effluents. Also the research has included the characterization of generated effluents in order to evaluate the effectiveness of the treatment applied, and the possibility of further treatment. The second phase involved the characterization of the generated sludge after the treatment of effluents that contained dyes and its treatment with solidification and stabilization technique. The determination of used immobilization agents effectiveness was Conducted to determine the efficacy of immobilization agents in S / S treatment and the dominant mechanism of leaching of metals that describe their transport from the received solidificate . Were applied and modified leaching tests with the aim of better simulation of real conditions. The results obtained by condition simulation will enable the modeling of behavior of metals in terms of long-term leaching period from the treated sludge and assess the most effective agents for the immobilization of various metals in this type of waste. Also, single-extraction leaching tests were applied to ensure the accordance of obtained results with the maximum permissible concentrations of current regulations. Based on these results, it was concluded that the pyrite cinders can be successfully used as a source of catalytic iron in Fenton treatment of effluents containing dyes, and can be considered an effective pretreatment method for non-biodegradable waste waters, making them amenable to conventional biological treatment. Also in the second phase, based on the results obtained, it was concluded that the sludge treated with aforementioned immobilization agents represents a successfully solidified and stabilized material. The optimal mixtures are those that contain fly ash as one of the used immobilization agents, primarily in combination with cement and lime. The obtained data are invaluable in terms of economic and environmentally sound management of hazardous industrial waste.</p>
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Uticaj starenja stabilizovanog i solidifikovanog sedimenta na strukturne karakteristike matriksa i izluživanje metala / Influence of aging of stabilized and solidified sediment on the structural characteristics of the matrix and metal leachingRađenović Dunja 09 October 2020 (has links)
<p>Predmet izučavanja ove disertacije obuhvatio je ispitivanje uticaja starenja stabilizovanog/solidifikovanog (S/S) sedimenta zagađenog teškim metalima i arsenom, i efikasnost primenjenih imobilizacionih agenasa (Portland cement, kreč, leteći pepeo, zeolit, montmorilonit i kaolinit) nakon dugogodišnjeg starenja S/S smeša. Shodno tome ispitana je dugoročna stabilnost i postojanost dobijenih S/S smeša sa aspekta izluživanja pomenutih metala, promene u minerološkim i strukturnim karakteristikama, kao i uticaj sušenja i zrenja materijala na pomenute parametre. Istraživanja u disertaciji obuhvatila su dve faze. Prva faza imala je za cilj procenu rizika i početnu karakterizaciju netretiranog sedimenta primenom analize pseudo-ukupnog sadržaja metala kojom je utvrđen sadržaj metala u početnom uzorku sedimenta. Druga faza uključivala je primenu tretmana stabilizacije i solidifikacije na kontaminirani sediment dodavanjem različitih imobilizacionih agenasa. Analize su se vršile nakon 7 i 28 dana od primenjenog S/S tretmana, kao i nakon 7 godina sa ciljem da se utvrdi uticaj višegodišnjeg starenja i zrenja monolitnih smeša na mobilnost metala i strukturne karakteristike smeša. U okviru druge faze istraživanja ispitana je toksičnost S/S smeša primenom DIN i TCLP testova izluživanja, dok je test toksičnosti primenom bakterija Vibrio Fischeri doprineo u sagledavanju procene rizika S/S smeša po organizme. Nakon 28 dana i 7 godina korišćena je sekvencijalna ekstrakcija za određivanje mobilnost i biodostupnost metala u monolitnim matriksima. U cilju utvrđivanja mikrostukturnih karakteristika sedimenta primenjena je rendgenska difrakciona analiza (XRD) za ispitivanje kristalnih struktura S/S smeša i detekciju mineralnog sastava. Pomoću elektronskog mikroskopa i energodisperzivnog detektora sa X-zrakom (SEM/EDS) određena je kvalitativna i kvantitativna distribucija metala i drugih elemenata od interesa, dok se za identifikaciju formiranih funkcionalnih grupa u monolitnim smešama primenio spektrometar sa infracrvenom Furijeovom transformacijom (FTIR). Na osnovu dobijenih rezultata zaključeno je da se mobilnost teških metala i arsena značajno smanjila nakon 7 godina za smeše tretirane cementom (C5), krečom (L10), letećim pepelom (F30) i kaolinitom (K20), a efekat stabilizacije je pokazan transformacijom metala iz direktne toksične frakcije u stabilnije oblike. Smeše C5 i K20 ispoljavaju najmanje toksične efekate od svih smeša, jer je procenat inhibicije na bioluminiscentnim bakterijama manji od 13%, dok je u pogledu izdržljivosti monolitna smeša C5 pokazala najveću pritisnu čvrstoću od svih smeša. Dobijeni podaci su neprocenjivi za dobijanje stvarnog uvida u dugoročnu efikasnost primenjenog tretmana i mogućnost bezbedne upotrebe ili odlaganja dobijenih S/S smeša sa aspekta zaštite životne sredine, kao i ekonomski i ekološki prihvatljivog upravljanja opasnim otpadom.</p> / <p>The subject of study in this dissertation included to investigate the effect of aging of stabilized/solidified (S/S) sediment contaminated with heavy metals and arsenic, and the efficacy of the applied immobilization agent (Portland cement, lime, fly ash, zeolite, montmorillonite and kaolinite) after long-term aging of S/S mixtures. The<br />long - term stability and stability of the obtained S/S mixtures from the aspect of leaching of the mentioned metals, changes in mineralogical and structural characteristics, as well as the influence of drying and maturation of the material on the mentioned parameters were examined. The research in the dissertation included two phases. The first phase aimed at risk assessment and initial characterization of untreated sediment using pseudo-total metal content analysis which determined the<br />metal content in the initial sediment sample. The second phase involved applying stabilization and solidification treatments to the contaminated sediment by adding various immobilizing agents. The analyzes were performed after 7 and 28 days from the applied S/S treatment, as well as after 7 years in order to determine the influence of perennial aging and maturation of monolithic mixtures on metal mobility and structural characteristics of the mixtures. In the second phase of the study, the toxicity of S/S mixtures using DIN and TCLP leaching tests was examined, while the toxicity test using bacteria Vibrio Fischeri contributed to the assessment of the risk of S/S mixtures to organisms. After 28 days and 7 years, sequential extraction was used to determine the mobility and bioavailability of metals in monolithic matrices. In order to determine the microstructural characteristics of the sediment, x-ray diffraction analysis (XRD) was used to examine the crystal structures of S/S mixtures and to detect the mineral composition. The qualitative and quantitative distribution of metals and other elements of interest was determined using an electron microscope and an energy-dispersive X-ray detector (SEM / EDS), while an infrared Fourier transform spectrometer(FTIR) was used to identify the formed functional groups in monolithic mixtures. Based on the obtained results, it was concluded that the mobility of heavy metals and arsenic decreased significantly after 7 years for mixtures treated with cement (C5), lime (L10), fly ash (F30) and kaolinite (K20), and the stabilization effect was shown by transformation of metals from direct toxic fractions into more stable forms. Mixtures C5 and K20 exhibit the least toxic effects of all mixtures, because the percentage of inhibition on bioluminescent bacteria is less than 13%, while in terms of durability, the monolithic mixture C5 showed the highest compressive strength of all mixtures. The obtained data are invaluable for gaining real insight into the long-term efficiency of the applied treatment and the possibility of safe use or disposal of the obtained S/S mixtures from the aspect of environmental protection, as well as economically and ecologically acceptable hazardous waste management.</p>
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Optimizacija sastava nosećeg sloja kolovozne konstrukcije na bazi agregata od hladno recikliranog asfalta sa aspekta mehaničkih karakteristika / Optimization of the pavement base layer content on the basis of thereclaimed asphalt pavement aggregate in terms of mechanicalpropertiesJakovljević Radomir 21 September 2016 (has links)
<p>U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja<br />izvršenog na uzorcima pripremljenim sa različitim učešćem struganog asfalta (RAP)<br />i dodatnog - "novog" drobljenog kamenog agregata. Variranjem učešća struganog<br />asfalta i dodatnog drobljenog kamenog agregata i variranjem učešća oba veziva<br />omogućeno je praćenje uticaja sastava na mehaničke karakteristike mešavine.<br />Uticaj vrste i količine upotrebljenog veziva na mehaničke karakteristike nosećeg<br />sloja kolovoza sagledano je kroz variranje sadržaja cementa i bitumenske emulzije.<br />Predmet istraživanja je definisanje međusobne zavisnosti odnosno korelacije,<br />određenih mehaničkih karakteristika mešavine u funkciji vrste i količine<br />komponentnih materijala i veziva i ocena njihovih fundamentalnih mehaničkih<br />karakteristika.</p> / <p>In dissertation are resented results of own experimental research on<br />samples that have been prepared with different amount of reclaimed<br />asphalt (RAP) and the additional - "new" crushed stone aggregate. By<br />varying participation of reclaimed asphalt and additional crushed stone<br />and varying participation of both binders monitoring of the impact of the<br />composition on the mechanical properties of the mixture was enabled.<br />The influence of type and amount of binder on the mechanical properties<br />of the pavement base layer is seen through variation in the content of<br />cement and bitumen emulsion. The subject of the research is to define the<br />mutual dependence and correlation of certain mechanical characteristics<br />of the mixture as a function of the types and quantities of component<br />materials and binders and evaluation of their fundamental mechanical<br />properties.</p>
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Elektrokoagulacioni i adsorpcioni tretmani efluenata u grafičkim procesima ofset štampe / Electrocoagulation and Adsorption Treatments of Effluents in Offset Printing Graphic ProcessesAdamović Savka 09 September 2016 (has links)
<p>Predmet doktorske disertacije je uklanjanje neorganskih i organskih polutanata iz efluenata ofset tehnike štampe (otpadnog razvijača i otpadnog sredstva za vlaženje) u cilju minimiziranja njihovog štetnog uticaja na životnu sredinu. Uklanjanje polutanata sprovedeno je primenom elektrokoagulaciono/ flotacionog (EKF) tetmana, adsorpcionog (AD) tretmana i kombinacijom navedenih tretmana. Izvodljivost i efikasnost tretmana analizirana je ispitivanjem uticaja karakterističnih operativnih promenljivih u okviru procesa na smanjivanje količine polutanata. Mehanizmi EKF i AD tretmana definisani su na osnovu teorijskih matematičko kinetičkih modela. Za rešavanje problema odlaganja mulja nastalog nakon EKF tretmana primenjen je solidifikaciono/stabiliza-cioni tretman sa odgovarajućim imobilizacionim agensima. Razvijen je efikasan model kombinacije tretmana efluenata grafičkih procesa ofset štampe kojim je omogućena konverzija efluenata u proizvode kompatibilne sa principima i normativima životne sredine.</p> / <p>The topic of this doctoral dissertation is the removal of inorganic and organic pollutants from the offset printing effluents (waste developer and waste fountain solution) in order to minimize their damaging influence onto the environment. The removal of the pollutants has been performed by electrocoagulation/flotation (ECF) treatment, adsorption (AD) treatment and the combination of the two said treatments. Feasibility and efficacy of the treatments has been analyzed by investigating the effect of characteristic operational variables within the process on the decrease in the quantity of pollutants. The mechanisms of ECF and AD treatments have been defined on the basis of theoretical mathematical-kinetic models. For the solution of the problem of sludge disposal, originating from the ECF treatment, a solidification/stabilization treatment with immobilization agents has been applied. An efficient model that combines the offset printing effluent treatments has been developed, the one which enables the conversion of effluents into products compatible with environmental principles and norms.</p>
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Uklanjanje metala iz vode primenom stabilisanog i „zelenom“ sintezom produkovanog nano gvožđa (0) / Removal of metals from water using stabilized and “green” method produced nano iron (0)Poguberović Sofija 04 July 2016 (has links)
<p>Predmet izučavanja ove disertacije je ispitivanje mogućnosti primene stabilisanog nano Fe(0) i „zelenom“ sintezom produkovanog nano Fe(0) u uklanjanju Cr(VI), Cd(II), Cu(II), Ni(II), Pb(II) i As(III) iz vode. Sinteza nano Fe(0) za stabilizaciju izvršena je konvencionalnom metodom redukcije gvožđa sa natrijum borhidridom u prisustvu materijala za stabilizaciju: kaolinita, bentonita i karboksimetil celuloze. Za „zelenu” sintezu nano Fe(0) korišćeno je lišće drveća: hrasta, duda i višnje. Karakterizacija dobijenih nanomaterijala izvršena je transmisionom i skenirajućom elektronskom mikroskopijom. Rezultati karakterizacije su pokazali da se tokom sinteze nano Fe(0) natrijum borhidridom i stabilizacije kaolinitom, bentonitom i karboksimetil celulozom, formiraju nano čestice Fe(0) veličine 20 do 90 nm, dok su veličine čestica nano Fe(0) sintetisanih „zelenom“ metodom iznosile 10-30 nm i okarakterisane su kao nano čestice sfernog oblika, različitih veličina bez značajane aglomeracije. Primena nano Fe(0) na efikasnost uklanjanja metala iz vode ispitivana je pri različitim uslovima: uticaju doze nanomaterijala, početne koncentracije metala, pH vrednosti rastvora i kontaktnog vremena. Dobijeni rezultati prilikom ispitivanja uticaja doze nanomaterijala na efikasnosti uklanjanja odabranih metala iz vode primenom stabilisanih i „zelenih“ nanomaterijala pokazali su da se povećanjem doze nanomaterijala povećava efikasnost uklanjanja. Prilikom primene stabilisanih nanomaterijala, koncentracije 14.00 gFe(0)/l, postignute su visoke efikasnosti uklanjanja, već pri dozama od 2 ml, dok je efikasnost uklanjanja primenom „zelenih“ nanomaterijala koncentracije 1,395 gFe(0)/l bila niža. Prilikom ispitivanja uticaja pH vrednosti na uklanjanje metala iz vode primenom ispitivanih nanomaterijala, određeni su optimalni opsezi pH vrednosti pri kojima se postiže najveća adsorpcija metala na ispitivanim nanomaterijalima. Veza između metala i ispitivanih nanomaterijala objašnjena je modelovanjem Langmuir-ove i Freunlich-ove adsorpcione izoterme. Veće adsorpcione kapacitete prilikom adsorpcije svih ispitivanih metala pokazali su nanomaterijali produkovani „zelenom“ sintezom u odnosu na stabilisane nanomaterijale, što je povezano sa veličinom čestica, tj. manje nanočestice nanomaterijala produkovanih „zelenom” sintezom imaju veću specifičnu površinu i samim tim mogu ponuditi više reaktivnih mesta, veću reaktivnost i bolju disperziju. Ispitivanje kinetike adsorcije Cr(VI), Cd(II), Cu(II), Ni(II), Pb(II) i As(III) na ispitivanim stabilisanim i „zelenom“ sintezom produkovanim nanomaterijalima pokazalo je veoma brzu reakciju adsorpcije metala na ispitivanim nanomaterijalima i bolje slaganje eksperimentalno dobijenih podataka sa pseudo-drugim kinetičkim modelom. Rezultati dobijeni u ovom istraživanju omogućiće procenu primene nano Fe(0) za uklanjanje metala iz vode, posebno adsorpciju metala iz vode kao i odabir najefikasnijeg i najekonomičnijeg adsorbensa za uklanjanje različitih metala iz vode.</p> / <p>This work is concerned with exploring the possibility of application of stabilized nano Fe(0) and nano Fe (0) produced by “green” synthesis in the removal of Cr(VI), Cd(II), Cu(II), Ni(II), Pb(II) and As(III) from the water. Synthesis of nano Fe(0) for the stabilization is carried out according to conventional method of iron reduction with sodium borohydride in the presence of a material for stabilization: kaolinite, bentonite and carboxymethyl cellulose. Leaves of oak, mulberry and cherry trees used for “green” synthesis of nano Fe(0). Characterization of nanomaterials was performed by transmission and scanning electron microscopy. The characterization results have shown that during the synthesis and stabilization of nano Fe (0) process formed nanoparticles with size from 20 to 90 nm, while the nano Fe (0) particles synthesized by "green" method were within the size of 10-30 nm and characterized as spherical nanoparticles with various sizes without significant agglomeration. Application of nano Fe (0) on the removal efficiency of metals from water was studied under different conditions: the influence of nanomaterials dose, the initial metal concentrations, pH value of the solution and the contact time. The results obtained during the examination of the impact of nanomaterial dose on the removal efficiency of selected metals from water have shown that increasing of nanomaterial dose increases removal efficiency. High removal efficiency is achieved when used 2 ml of stabilized nanomaterials, concentration of 14.00 gFe(0)/L, while when "green" nanomaterials, concentration of 1,395 gFe(0)/L, were used the removal efficiency was lower. The optimal ranges of pH values at which the tested nanomaterials reach the maximum adsorption of metals were obtained, during the examination of the influence of pH value on removal of metals from water by using the tested nanomaterials The relation between the metals and tested nanomaterials is explained by modeling of Langmuir's and Freunlich's adsorption isotherm. Nanomaterials produced by "green" synthesis showed higher adsorption capacity than stabilized nanomaterials, which is related with particle size, i.e. the nanoparticles produced by "green" synthesis have less particles, higher specific surface area and therefore can offer more reactive sites, greater reactivity and better dispersion. Kinetics tests showed a very fast adsorption of metal on the tested nanomaterials and better agreement with the experimental data to second pseudo-kinetic model. The results obtained in this study will enable the assessment of the application of nano Fe (0) for the removal of metals from water, especially for the adsorption of metals from water as well as the selection of the most efficient and most economical of the adsorbent for the removal of various metals from water.</p>
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