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Zaštita Materijala 4. 2016


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Vincenzo Leone1*, Pasquale Iovino1, Elio Coppola1, Stefano Salvestrini1, Sante Capasso2

1Second University of Naples, Department of Environmental, Biological and Pharmaceutical Science and Technologies, Caserta, Italy, 2University of Naples, Environmental Technologies University Spin-off, Second Caserta, Italy

 

 

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604515L

Zastita Materijala 57 (4)
515 – 518  (2016)

Sorption of organic pollutants onto zeolitic tuff

Abstract

The isotherms of sorption of six organic pollutants (phenylmethanol (benzyl alcohol), phenol, cyclohexanol, o-xylene, toluene and cyclohexane) from water solutions onto zeolitic tuff (Si/Al ratio = 2.4) have been determined by batch experiments at 25 °C, in 1.0∙10-3 mol dm-3 Tris-HCl buffer, pH 6.0. The solutions were analyzed by gas-chromatography. The best description of the experimental data was given by the Freundlich equation, whose constants have been determined and compared with literature data.

Keywords: organic pollutants; zeolitic tuff; sorption.

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Sorpcija organskih zagađivača na zeolitskom tufu

Izvod

Izoterme, koje prikazuju sorpciju šest organskih zagađivača (fenil methanol – benzyl alcohol, fenol, cikloheksanol, o-ksilen, toluen i cikloheksan), iz vodenih rastvora, na zeolitskom tufu (Si/Al odnos =2.4), su određene šaržnim postupkom, na  25°C, u rastvoru pufera – 1.0∙10-3 mol dm-3 Tris-HCl (pH 6.0). Rastvori su analizirani na gasnom hromatografu. Najbolje slaganje eksperimentalnih rezultata je postignuto sa Frojndlih-ovim sorpcionim modelom, čije konstante su određene i upoređene sa literaturnim podacima.

Ključne reči: organski zagađivači, zeolitski tuff, sorpcija.

Dalje>>>

 


 

 

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Blagica Cekova1*, Filip Jovanovski2, Viktorija Bezhovska2

1MIT University, Faculty of ecological resources menagment, Skopje, Republic of Macedonia, 2University of Skopje,  Faculty of Technology and Metallurgy, Skopje, Republic of Macedonia

 

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604519C

Zastita Materijala 57 (4)
519 – 522  (2016)

Modification of NaY zeolite by citric acid through application of tensides

Abstract

The zeolites are popular group of minerals for collectors and important group of minerals for industrial and other purposes. They combine rarity, beauty, complexity and unique crystal habits. Typically forming in the cavities, or vesicles, of volcanic rocks, zeolites are the result of very low grade metamorphism. Some are formed  from just subtle amounts of heat and pressure and can just barely be called metamorphic, while others are found in obviously metamorphic regimes. There is undergoing extensive research into the formation of zeolites and their unique properties.

The NaY zeolite is analogue to the natural zeolite phosphazide and belongs to the IVth group according to the zeolite classification. The typical composition of NaY elementary cell is Na56[(AlO2)56(SiO2)136]·250H2O containing double hexagonal rings (D6R). This research was focused on a NaY zeolite, obtained by hydro-thermal procedure with a chosen oxide ratio: SiO2/Al2O3 = 9.0; Na2O/SiO2 = 0.33; H2O/Na2O = 40. The chemical composition of the starting mixture for the synthesis is determined by the chemical formula 2.97Na2O·Al2O3·9SiO2·118.8H2O. The dealumination process on the NaY zeolite was performed by application of citric acid with concentrations of 0.1 and 0.5 mol/dm3 and introduction of tensides (I, II, III, IV). Dealumination procedure is conducted in order to extract the most of the Al content from the zeolite structure while preserving the crystal structure, with crystalinity above 50%. NaY zeolite has a solid structure and therefore a dealumination process is required in order to modify this material into a suitable catalyst, as well as for other uses. Obtained products were analyzed by X-Ray, and DTA, TGA and DTG. The results of the performed dealumination are presented in tables. Crystalinity was determined as 56.90%, compared to the crystalinity of the commercial zeolite that has a reported crystalinity of 100%.

Keywords: dealumination, citric acid, NaY zeolite, crystalinity.

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Modifikacija NaY zeolita sa limunskom kiselinom sa primenom na tenzide

Izvod

Zeoliti su popularna grupa minerala za kolekcionare i značajna grupa minerala za industrijske i druge svrhe. Oni kombinuju retkost, lepotu, složenost i jedinstvene kristalne oblike. Tipično, formiraju se u šupljinama ili kesicama od vulkanskih stena. Zeoliti su rezultat veoma niske razrade metamorfizma. Neki oblik zeolita od samo suptilnim količina toplote i pritiska se jedva može nazvati metamorfoznim dok ostali se nalaze u očigledno metamorfnim režimima. Postoje polazna opsežna istraživanja u formiranju zeolita i njihovim jedinstvenim svojstvima.

NaY zeolit je analog sa prirodnim zeolitom fosfazida i pripada četvrtoj grupi prema klasifikaciji zeolita. Tipičan sastav NaY osnovne ćelije Na56 [(AlO2)56 (SiO2) 136] • 250 SiO2 sadrže dvostruke heksagonalne prstenove (D6R). Ovo istraživanje je fokusirano na NaY zeolite, dobijene hidrotermalnim procesom sa izabranim oksidnim odnosom: SiO2 /Al2O3 = 9,0;  Na2O/SiO2 = 0,33 i H2O/Na2O = 40. Hemijski sastav polazne smeše za sintezu određuje hemijsku formulu 2.97 Na2O • Al2O3 • 9 SiO2 • 118.8 H2O. Proces dealuminacije na NaY zeolitu je izveden primenom limunske kiseline sa koncentracijama 0,1 i 0,5 mol/ dm3 i uvođenjem tenzida (I, II, III, IV). Dealuminatni postupak se izvodi kako bi se izvukla većina sadržaja Al sa zeolitne strukture, čuvajući kristalnu strukturu, uz kristalnost iznad 50%. NaY zeolit ima solidnu strukturu i zato je potreban proces dealuminacije da bi se modifikovao ovaj materijal u prikladnog katalizatora i za druge namene. Dobijeni proizvodi su analizirani sa X-Ray,  DTA, TGA i DTG. Rezultati izvršene dealuminacije su predstavljeni u tabelama. Kritalnost dobijenog zeolita je određena sa 56.90%, u poređenju sa kristalnošću komercijalnog zeolita, koji ima prijavljenu kristalnost od 100%.

Ključne reči: dealuminacija, limunska kiselina,  NaY zeolit, kristalnost.

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Danijela Rajić1*, Dragan Tošković1, Ljubica Vasiljević1, Željko Ostojić2

1Univerzitet u Istočnom Sarajevu, Tehnološki fakultet, Zvornik, Republika Srpska, 2Alumina d.o.o., Zvornik, Republika Srpska

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604523R

Zastita Materijala 57 (4)
523 – 532  (2016)

Određivanje uticaja organskih i neorganskih mikroprimesa na fizičko-hemijske karakteristike deterdžentskog zeolita tipa 4A

Izvod

U ovom radu je izvršena sinteza deterdžentskog zeolita tipa 4A pri tačno određenim uslovima sa vremenom kristalizacije od 4 časa na temperaturi 85°C. Sintetisani su zeoliti bez primjesa sa čistim polaznim sirovinama kao i zeoliti sa dodatkom organskih i neorganskih primjesa dodatkom sljedećih supstanci: Na2SO4, CaSO4, CaCl2 , FeSO4 i Na2C2O4. Istraživanja su vršena u laboratorijskim uslovima i omogućila su definisanje zavisnosti fizičko-hemijskih karakteristika zeolita od uticaja primjesa u odnosu na zeolit dobijen bez primjesa. Za karakterizaciju dobijenog zeolita korištena je Atomska apsorpciona spektrofotometrija, Rendgeno strukturna analiza, kao i klasične hemijske analize. Nakon istraživanja utvrđeno je da sulfati u bilo kom obliku znatno pogoršavaju kvalitet dobijenog zeolita za razliku od hloridih jona. Oksalati pogoršavaju njegov kvalitet prema svim ispitivanim parametrima (npr. JIK 80,52 mgCaO/g suvog zeolita). Oprezni moramo biti naročito sa koncentracijom Fe3+ jona jer znatno smanjuje bjelinu (88,40%) u koncentraciji od 0,08g/L. Ovim ispitivanjima su se otvorile nove mogućnosti za ispitivanje uticaja koje primjese imaju na zeolite. Neke od primjesa dovode do promjene u kristalnoj strukturi tako da se ne dobija 4A tip nego zeolit drugačije strukture i karakteristika.

Ključne riječi: zeolit, mikroprimjese, jonoizmjenjivački kapacitet, sinteze zeolita.

Dalje>>>

Determination of the influence of organic and  inorganic impurity on physico-chemical properties of detergent zeolite type 4A

Abstract

This paper shows  the synthesis of detergent zeolite type 4A, on the precise conditions of crystallization with time of 4 hours at 85 ° C. Zeolites without impurities were synthesized with clean raw material and also zeolites with the addition of organic and inorganic impurities by adding the following substances: Na2SO4, CaSO4, CaCl2, FeSO4 i Na2C2O4.  The studies were conducted in laboratory conditions and enabled the definition depending on the physical and chemical characteristics of zeolite from the influence of impurities in comparison with zeolite obtained without impurities. For the characterization of the resulting zeolite was used Atomic absorption spectrophotometry, X-ray structural analysis, as well as classical chemical analysis. This synthesis shows that sulfates in any form significantly deteriorate the quality of the obtained zeolite in contrast to chloride ions. Oxalates worsen its quality to all tested parameters (eg. JIK 80.52 mgCaO / g dry zeolite). We have to be careful especially with the concentration of Fe 3+ ions as significantly reduce the whiteness (88.40%) at a concentration of 0,08g/L. These studies have opened up new possibilities for studying the influence that impurities have on zeolites. Some impurities lead to changes in the crystal structure so we do not get a 4A type than zeolite different structure which has worse characteristic.

Keywords: zeolite, impurities, physic-chemical properties, synthesis

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Ljubica Vаsiljević1*, Branko Škundrić2,
Miladin Gligorić1, Časlav Lačnjevac3

1Univerzitet u Istočnom Sаrаjevu, Tehnološki fаkultet Zvornik, Zvornik, Republika Srpska, 2Akаdemijа nаukа i umjetnosti Republike Srpske, Banja Luka,  Republika Srpska, 3Univerzitet u Beogradu, Poljoprivredni fakultet, Beograd, Republika Srbija

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604533V

Zastita Materijala 57 (4)
533 – 538  (2016)

Zavisnost apsorpcije lutensola, kristaličnosti i specifične površine od temperature kristalizacije zeolita

Izvod

U cilju određivanja zavisnosti apsorpcije lutensola, kristaličnosti i specifične površine na zeolitu sintetisanom pri različitim temperaturama kristalizacije, praćena je promjena kristaličnosti (XRD), apsorpcija lutensola (LUT), srednji prečnik čestica (Ds50%), specifična površina,a urađena je i skenirajuća elektronska mikroskopija (SEM) sintetisanih uzoraka zeolita. Sinteza uzoraka se odvijala na temperaturi kristalizacije 70, 75, 80, 85 i 90°C, dok su sirovine ( Na-aluminat i Na-silikat) bile na temperauri 90°C  na početku sinteze. Srednji prečnik čestica kretao se zavisno od temperature kristalizacije u skladu sa principima autokatalitičke nukleacije i „efekta pamćenja“ gela. Povećanje kristaličnosti u sintezama sa manjom apsorpcijom lutensola uočeno je u analiziranim sistemima sa temperaturom kristalizacije od 75°C. Na temperaturi kristalizacije od 90°C kristaličnost znatno pada i iznosi 37,87%, dok apsorpcija raste na račun povećanja udjela drugih nezeolitnih vrsta. Ovo potvrđuje i SEM analiza. Specifična površina se smanjuje sa povećanjem udjela kristalne faze zeolita A, od 11,30 do 2,14 m2/g zeolita.

Ključne reči: apsorpcija lutensola, kristaličnost, temperatura kristalizacije, zeolit.

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The absorption of lutensol, crystallinity and specific surface area depending on the zeolite crystallization temperature

Abstract

In order to determine the dependence of absorption Lutensol, crystallinity and specific surface area of the zeolite synthesized at different temperatures crystallization was performed by a change in crystallinity (XRD), absorption Lutensol (LUT), average diameter of particles (DS50%), specific surface area and  scanning electron microscopy (SEM) synthesized zeolites. Synthesis of the samples was held at a temperature of crystallization of 70, 75, 80, 85 and 90°C, while the raw material (Na-aluminate and of Na-silicate) were at temperatures of 90°C at the start of the synthesis. Average diameter of particles varied depending on the temperature of crystallization in accordance with the principles of autocatalytic nucleation and the “memory effect” of the gel.

Increasing the crystallinity of the synthesized samples with low oil absorption was observed in the analyzed system of the crystallization temperature of 75 ° C. At the temperature of crystallization 90 °C  crystallinity is significantly decrease at  37.87 % while  absorption of  Lutensol increases at the expense of increasing the of other types of non zeolites  kinds. This is confirmed by SEM analiza. Specific  surface area decreases with conclusive increase of the crystal phase zeolite A, from 11.30 to 2.14 m2/g zeolite.

Keywords: absorption Lutensol, crystallinity, crystallization temperature, zeolite.

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Jelena Pavlović1*, Tore Krogstad2,
Nevenka Rajić3

1University of Belgrade, Innovation Centre of the Faculty of Technology and Metallurgy, Belgrade, Serbia, 2Norwegian University of Life Sciences, Faculty of Environmental Science and Technology, Norway, 3University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604539P

Zastita Materijala 57 (4)
539 – 544  (2016)

 Influence of the Fe(III)-modified clinoptilolite on phosphorus leaching from different soil types

Abstract

Influence of the iron(III)-modified clinoptilolite (FeCLI) on phosphorus leaching from two different Norwegian soil types (sand and clay loam soil) was studied using a column system at room temperature. FeCLI was used in different amounts of 0.5, 1.5 and 2.5 wt. %. The obtained results indicate that the presence of FeCLI causing a reduction of phosphorus leaching from both soil types. The reduction efficiency increases with the FeCLI amount. Addition of 2.5 wt.% FeCLI to the soils decreased the phosphorus leaching by 48 % from clay loam soil and by 42 % from sand soil compared to the control systems. FeCLI also increased pH of the soils from 5.1 to 7.0 for sand and from 5.7 to 7.7 for clay loam soil. All obtained results indicate that FeCLI is a promising soil supplement for the studied soil types due to phosphorus preservation and a decrease of soil acidity.

Keywords: phosphorus, soil, phosphorus leaching, eutrophication, natural zeolite, iron-clinoptilolite.

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Uticaj Fe(III)-modifikovanog klinoptilolita na izluživanje fosfora iz različitih vrsta zemljišta

Izvod

U radu je ispitivan uticaj gvožđe(III)-modifikovanog klinoptilolita (FeCLI) na izluživanje fosfora iz dve različite vrste norveškog zemljišta (pesak i glinovita ilovača). Eksperimenti su izvedeni u kolonama na sobnoj temperaturi. FeCLI je dodavan u različitim koncentracijama 0,5; 1,5 i 2,5 mas. %. Dobijeni rezultati ukazuju da FeCLI doprinosi smanjenju izluživanja fosfora kako iz peskovitog, tako i iz glinovito ilovačastog zemljišta. Efikasnost FeCLI raste sa povećanjem koncentracije FeCLI u zemljištu. U koncentraciji 2,5 mas.% FeCLI smanjuje izluživanje fosfora za 48 % (iz glinovite ilovače) i 42 % (iz peskovitog zemljišta). Takođe, FeCLI povećava pH zemljišta: od 5,1 do 7,0 (pesak) i 5,7 do 7,7 (glinovita ilovača). Dobijeni rezultati ukazuju da je FeCLI perspektivan suplement koji doprinosi zadržavanju fosfora u zemljištu i smanjenju kiselosti obe vrste ispitivanih zemljišta.

Ključne reči: fosfor, zemljište, izluživanje fosfora, eutrofikacija, prirodni zeolit, gvožđe-klinoptilolit.

Dalje>>>

 


 

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Valentina A. Nikashina1*, Inna B. Serova1, Tatjana G. Kusmina1, Irma A. Roschina1, Irina N.Gromyak1, Nadezhda Lihareva2, Ognjan Petrov2

1Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow, Russia, 2Institute of Mineralogy and Crystallography, BAS, Sofia,Bulgaria

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604545N

Zastita Materijala 57 (4)
545 – 550  (2016)

Features of kinetics of Sr2+ sorption from surface drinking water on clinoptilolites from Russian and Bulgarian deposits

Abstract

The kinetics of Sr2+ ion-exchange process on NH4+– forms of clinoptilolites from deposits in Russia and Bulgaria on the sample of the surface drinking water was investigated in detail. It was shown, that the kinetic process on clinoptilolite includes 3 stages. The obtained data are the initial one for the development of a mathematical model of the dynamic ion-exchange process on NH4+-form of clinoptilolites from diluted solutions that makes possible to generate the computer program and thereupon to calculate the break-through curves of Sr2+ sorption on NH4+- clinoptilolite for different dynamic conditions.

Keywords: clinoptilolite, Sr2+ ion-exchange, kinetics, the surface drinking water, mathematical model.

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Karakteristike kinetike sorpcije Sr2+ iz površinskih pijaćih voda na klinoptilolitu iz Ruskih i Bugarskih ležišta

Izvod

U radu je ispitivana kinetika procesa jonske izmene Sr2+ na NH4+-formama klinoptilolita iz ležišta u Rusiji i Bugarskoj. Eksperimenti su rađeni sa realnim uzorkom površinske vode za piće.  Pokazano je da kinetika procesa jonske izmene Sr2+ na klinoptilolitu uključuje tri stupnja. Dobijeni rezultati su neophodni za razvijanje matematičkog modela koji bi opisao proces jonske izmene, iz razblaženih rastvora, na NH4+-formama klinoptilolita u dinamičkim uslovima. Model bi bio osnova da se napravi kompjuterski program koji bi omogućio proračune krivih proboja za adsorpciju Sr2+ na NH4+-klinoptilolitu pri različitim dinamičkim uslovima.

Ključne reči: klinoptilolit, Sr2+  jon-razmena, kinetika, površine vode za piće, matematički model.

Dalje>>>

 


 

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Srđan Matijašević1*,  Snežana Zildžović1,
Jovica Stojanović1, Marija Đošić1, Jelena Nikolić1, Mirjana Stojanović1,  Nebojša Labus2

1Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade, Serbia, 2Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604551M

Zastita Materijala 57 (4)
551 – 558  (2016)

Removal of uranium (VI) from aqueous solution by acid modified zeolites

Abstract

The objective of this study was the review of natural zeolite, modified with acid, as a candidate material for the remediation of groundwater contaminated by uranium(VI). The modified zeolite samples were obtained by treatment of natural zeolite – clinoptilolite with acids: hydrochloric, oxalyc and citric. Starting and modified zeolites were characterized by chemical analysis, SEM, XRPD analysis, IR spectroscopy, thermal (TG/DT) analysis and by determination of cation exchange capacity, while starting and nonadsorbed amounts of uranium(VI) ion were determined by fluorometric method. Batch experiments were conducted to investigate the effect of solid/liquid ratio, pH and time on the U(VI) uptake by zeolite. Modification of zeolitic tuff with acids significantly increased adsorption of uranium(VI). The highest adsorption of uranium(VI) ion was achieved on clinoptilolite modified with hydrochloric acid. Uranium(VI) adsorption data for zeolite modified with hydrochloric acid was fitted to the Langmuir model.

Keywords: zeolite – clinoptilolite, acid modification, uranium(VI) adsorption.

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Uklanjanje uranil-jona iz rastvora kiselo tretiranim zeolitima

Izvod

Cilj ovog rada je prikaz mogućnosti primene prirodnog i modifikovanog zeolitskog minerala kao adsorbenta i materijala za sanaciju voda kontaminiranih uranijum jonom. Modifikovani uzorci zeolita dobijeni su tretiranjem prirodnog zeolita – klinoptilolita sa kiselinama: hlorovodoničnom, oksalnom i limunskom. Polazni i modifikovani zeoliti su okarakterisani hemijskom analizom, skenirajućom elektronskom mikroskopijom (SEM), rendgenskom analizom (XRPD), IC spektroskopijom, termičkom (TG/DTA) analizom i određivanjem kapaciteta katjonske izmene, a polazne i neadsorbovane količine uranijum jona su određene fluorimetrijski. Eksperimenti su sprovedeni da se ispita uticaj odnosa čvrsto/tečno, pH i vremena na adsorpciju uranijum jona na zeolitu. Utvrđeno je da tretman sa kiselinama zeolita povećava adsorpciju uranijum jona. Najviši indeks adsorpcije imao je uzorak zeolita modifikovan sa hlorovodoničnom kiselinom. Dobijeni rezultati adsorpcije na H-zeolitu su izračunati prema Langmirovom modelu.

Ključne reči: zeolit-klinoptilolit, modifikacija kiselinom, adsorpcija uranil-jona.

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Milan Kragović*, Aleksandra Daković, Marija Marković, Anđela Petković

Institute for technology of nuclear and other mineral raw materials, Belgrade, R.Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604559K

Zastita Materijala 57 (4)
559 – 564  (2016)

Kinetic of thermal degradation of alginate-zeolite composites

Abstract

In this work, natural and Fe(III)-modified zeolte were tested as additives for alginate in order to improve its thermal and pyrolytic properties. For that purpose the natural zeolite (NZA) and Fe(III)-modified zeolite coated with alginate (FeA) were used. Thermal degradation of the samples was investigated by using thermal analytic techniques, thermogravimetric (TG) and differential thermal analysis (DTA). The samples were heated from 25oC to 1000oC at different heating rates (from 5 to 20oC).  From experimental results, thermal degradation of the sodium alginate could be clearly separated into several stages based on the weight loss and the weight loss rate. The kinetic parameters (activation energy and pre-exponential factor) for the main degradation phase (from 180 to 500oC) thus were estimated by using the pseudo first-order assumption. The results showed that used zeolites affected the thermal properties of the alginate and reduce activation energy required for pyrolysis from 87.30 kJ/mol for pure alginate to 72.75 kJ/mol for NZA and 63.35 kJ/mol for FeA. These pyrolysis investigations can be useful for better understanding the thermal stability of these alginate biocomposites and provide necessary information for thermally processing wastes from these biodegradable materials.

Keywords: Na-alginate, natural zeolite, Fe(III)-modified zeolite, composite, thermogravimetric and differential thermal analysis, thermal degradation kinetic.

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Kinetika termijskog razlaganja kompozita alginata i zeolita

Izvod

U ovom radu ispitivana je upotreba prirodnog i Fe(III)-modifikovanog zeolite kao aditiva alginatu u cilju poboljšanja njegovih termijskih i pirolitičkih osobina. Za tu namenu korišćeni su uzorci prirodnog (PZA) i Fe(III)-modifikovanog zeolita prekrivenih alginatom (FeA). Sagorevanje uzoraka praćeno je termijskim analitičkim tehnikama, diferencijalnom termijskom analizom (DTA) i termogravimetrijskom analizom (TGA). Uzorci su zagrevani u temperaturskom intervalu od 25 do 1000oC pri različitim brzinama zagrevanja (od 5 do 20oC). Na osnovu eksperimentalnih rezultata, merenjem gubitka mase, termijsko razlaganje natrijum alginata se jasno može podeliti u nekoliko koraka. Na osnovu kinetičkog modela pseudo-prvog reda određeni su kinetički parametri (aktivaciona energija i pred eksponencijalni faktor) koji se odnose na temperaturski interval od 180 do 500oC. Dobijeni rezultati su pokazali da upotrebljeni zeoliti utiču na termijske osobine alginata kao i da smanjuju aktivacionu energiju potrebnu za njegovu pirolizu sa 87,30 kJ/mol za čist alginat na 72,75 kJ/mol za PZA i 63,35 kJ/mol za FeA. Ova ispitivanja mogu biti korisna za bolje razumevanje termijske stabilnosti alginatnih biokompozita i mogu dati informacije važne za termijske procese biorazgrađujućih materijala.

Ključne reči: Na-alginat, prirodni zeolit, Fe(III)-modifikovani zeolit, kompozit, termogravimetrijska i diferencijalna termijska analiza, kinetika termijske degradacije.

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Szilvia Ormándi*, István Dódony

Eötvös Loránd University, Dept. of Mineralogy, Budapest, Hungary

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604565O

Zastita Materijala 57 (4)
565 – 570  (2016)

Synthesis and structural study of the Linde Type-A zeolite prepared from kaolinite

Abstract

The goal of this work is to synthesize and measure the crystal structuras of sodalite-related zeolites using X-ray power diffraction technique. We made a successful attempt to recover the Linde Type A (LTA) zeolite framework using X-ray diffraction data sets. Cation exchange was done in this structure with Cs+ ions, in order to demonstrate the usability of LTA in the nuclear technique.

Linde Type A zeolite crystals were synthetized using (NaOH) method from metakaolinite as the starting material. The resulted LTA crystals exhibit cubic and spherical shapes as showned by scanning electron microscopy.

In the LTA framework the interchangeable cations are Na+ ions, which were replaced by (H3O)+ and Cs+ ions respectively. We measured the resulted structural changes, using X-ray powder diffraction data in the SIR (Semi Invariant Reconstruction) program package.

The measured hkl and intensity data sets are the inputs for structure determination. Due to overlapping reflections, some samples resulted in high R-factor values. However, the resulted LTA-type framework proved to be evident. We refined the atom position in the SHELX program package.

Keywords: synthesis, zeolite, kaolinite, metakaolinite, LTA, ion exchange Cs, SIR.

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Sinteza i ispitivanje strukture LTA zeolita dobijenog iz kaolina

Izvod

Cilj ovog rada je sinteza i ispitivanje kristalne strukture sodalitnog zeolita korišćenjem tehnike rendgenske difrakcije. Korišćenjem podataka dobijenih rendgenskom difrakcionom analizom uspešno je određena struktura kristalne rešetke LTA zeolita. Kako bi se pokazala upotrebljivost LTA u uklanjanju nuklearnog otpada u strukturi dobijenog uzorka urađena je jonska izmena sa Cs+ jonima.

Upotrebom metode sa NaOH iz metakaolinita kao početnog materijala sintetisani su kristali LTA zeolita. Skenirajućom elektronskom mikroskopijom pokazano je da su dobijeni LTA kristali kubnih i sfernih oblika.

U LTA rešetki izmenljivi katjoni (Na+ joni) izmenjeni su najpre H3O+ a zatim Cs+ jonima. Upotrebom SIR (Semi Invariant Reconstruction) softvera i korišćenjem podataka dobijenih rendgenskom spektroskopijom praćene su dobijene strukturne promene u uzorku.

Kao polazni podaci za strukturna određivanja korišćene su hkl vrednosti i intenziteti odgovarajućih spektralnih linija. Zbog preklapanja refleksija kod nekih uzoraka došlo je do pojave većih vrednosti R faktora. Ipak, očigledno je da je dobijen LTA tip rešetke. Softverski paket SHELIX je korišćen za prikazivanje preraspodele atomskih pozicija.

Ključne reči: sinteza, zeolit, kaolinit, metakaolinit, LPA, jonska razmena Cs, SIR.

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Munkhjargal Dashnyam1*, Oyuntsetseg Janchiv2, Ulambayar Renchinhand2, Ganbaatar Jamsranjav2

1Defenve university of Mongolia, Department of Mathematics and Computer Technology, Ulan Bator, Mongolia, 2Institute of Chemistry and Chemical technology, Mongolian Academy of Sciences, Ulan Bator, Mongolia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604571D

Zastita Materijala 57 (4)
571 – 576  (2016)

The investigation of the effect of relevant parameters of Mongolian natural zeolites for ammonium ion removal from aqueous solution

Abstract

Our study investigated the potential of natural tseolite for ammonium ions removal from aqueous solution. In batch study, the effect of relevant parameters such as pH, adsorbent dosage, contact time and initial ammonium concentration. Also, the effect pH investigated on ammonium removal of  aqueous solutions. The removal capacity of clinoptilolite increased by 15 minutes during our experiment.

The Langmuir and Freundlich model were applied to describe the equilibrium isotherms for ammonium uptake and the Freundlich model agree very well with experimental data. Based on the results, it can be concluded that the natural zeolite is suitable for removal of NH4+ ions  wastewater.

Кeywords: clinoptilolite, natural zeolites, ammonium ion, aqueous solution.

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Ispitivanje efekta relevantnih parametara Mongolskih prirodnih zeolita za uklanjanje amonijum jona iz vodenog rastvora

Izvod

U radu je ispitivan potencijal prirodnog zeolita iz ležišta u Mongoliji za uklanjanje amonijum jona iz vodenih rastvora. Razmatran je uticaj različitih parametara, kao što su pH rastvora, količina adsorbenta, vreme kontakta I početna koncentracija amonijum jona, na stepen uklanjanja amonijum jona. Rezultati su pokazali da pH rastvora utiče na efikasnost uklanjanja amonijum jona. Uklanjanje amonijum jona je brz process koji se dešava u prvih 15 min kontakta, a kapacitet adsorpcije klinoptilolita raste sa porastom početne koncentracije amonijum jona. Kod određivanja adsorpcionih izotermi, Langmir i Frojndlih modeli su primenjeni za fitovanje eksperimentalnih rezultata, i najbolje slaganje je postignuto sa Frojndlih-ovim modelom. Na osnovu dobijenih rezultata može se zaključiti da je prirodni zeolit iz ležišta u Mongoliji pogodan za uklanjanje  NH4+ jona iz otpadnih voda.

Ključne reči: klinoptilolit, prirodni zeoliti, amonijum jon, vodeni rastvor.

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Vesna Grekulović*, Mirjana Rajčić-Vujasinović,
Zoran Stević

Univerzitet u Beogradu, Tehnički fakultet u Boru, Bor, Srbija

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604577G

Zastita Materijala 57 (4)
577 – 581  (2016)

Uticaj vremena stajanja u rastvoru benzotriazola na anodno ponašanje legure AgCu50

Izvod

Uticaj benzotriazola na ponašanje srebra, bakra i legure AgCu50 pri anodnoj polarizaciji praćen je uranjanjem elektroda od ovih metalnih materijala u rastvor inhibitora koncentracije 0,01 mol/dm3 u trajanju od 30, 360, 720 i 1440 minuta, nakon čega su elektrode unošene u rastvor 0,1 mol/dm3 NaOH i ispitivane metodom ciklične voltametrije. Na cikličnim voltamogramima snimljenim za čisto srebro, čist bakar i leguru AgCu50 u 0,1 mol/dm3 NaOH nakon stajanja elektroda u 0,01 mol/dm3 BTA, vrednosti gustine struje anodnih strujnih pikova su manje u odnosu na vrednost gustine struje bez prethodnog kontakta elektroda sa rastvorom BTA. Tokom stajanja elektroda u rastvoru 0,01 mol/dm3 BTA formira se film AgBTA u slučaju srebra,  i CuBTA u slučaju bakra, koji štite površinu od korozije.

Ključne reči: srebro, bakar, BTA, ciklična voltametrija

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The effect of immersion time in a benzotriazole solution on anodic behaviour of AgCu50 alloy

Abstract

Electrochemical behavior of silver ,copper  and AgCu50 alloy after their immersion in 0.01 mol/dm3 benzotriazole solution for 30, 360, 720 i 1440 minutes, was investigated in 0.1 mol/dm3 NaOH using the cyclic voltammetry method. Currents on cyclic voltammograms for both, pure silver, pure copper and AgCu50 alloy recorded after imemersion in the benzotriazole solution are lower than the corresponding currents obtained without the contact of the metals with BTA. During the immersion of electrodes in solution of benzotriazole, a protective film of AgBTA is formed on silver and CuBTA film is formed on copper surface. Increasing in immersion time has a positive effect on silver and copper corrosion resistance in investigated solution.

Keywords: silver, copper, BTA, cyclic voltammetry

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Abd El-Aziz S. Fouda1*, Ayman Y. El-Khateeb2,
Hesham H. El-Zhery3, Mohamed Fakih4

1El-Mansoura University, Department of Chemistry, Faculty of Science, El-Mansoura, Egypt, 2Mansoura University, Department of Agric. Chemistry, Faculty of Agriculture, Mansoura, Egypt, 3Umm Al-Qura University, Health Science College at Al Leith, KSA,  Egypt, 4Lab manager in Talkha sanitation plant, water and wastewater company, Daqahlia, Egypt

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604583F

Zastita Materijala 57 (4)
583 – 596  (2016)

The role of aqueous ocimum basilicum extract for monitoring the corrosion inhibition of carbon steel used in sanitation plants and its effect on Escherichia coli

Abstract

The inhibitive effect of aqueous plant extract of Ocimum Basilicum was tested as green corrosion extract for CS(CS) in 3.5% NaCl and 16 ppm Na2S. It has excellent inhibition efficiency (% P) of about 88% provided by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The increase of the extract concentration leads to increase in the % P. The adsorption of the extract on the CS surface obeys Langmuir adsorption isotherm with physical adsorption on the metal surface. The analysis of EDX and SEM confirmed the formation of the extract precipitates on the metal surface, reducing the corrosion reaction.  The biological test of the extract on Escherichia Coli culture shows that there no effect on the biological activity of Escherichia Coli and can be applied safely without any harmful effect on sanitation plants.

Keywords: Ocimum Basilicum, EDX -SEM, Sanitation plants, Escherichia coli.

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Uloga vodenih Ocimum basilicum ekstrakta za praćenje inhibicije korozije ugljeničnih čelika korišćenih u sanitarnim postrojenjima i njihov uticaj na Escherichia coli

Izvod

Efekat vodenog ekstrakta bilja Ocimum basilicum je testiran kao ekstrakt zelene korozije za CS (CS) na 3,5% NaCl i 16 ppm Na2S. On ima odličnu efikasnost inhibicije (% p) od oko 88%, pod merenja smanjenja gubitka težine, potentiodinamičke polarizacije, elektrohemijske impedanse (EIS) i elektrohemijske frekvencije modulacije (EFM).  Povećanje koncentracije ekstrakta dovodi do povećanja u % P. Adsorpcija ekstrakta na CS površini prati Langmuirovu adsorpcionu izotermu sa fizičkom adsorpcijom na površini metala. Analiza EDKS i SEM potvrđuje da taloženje ekstrakta na metalnu površinu smanjuje reakciju korozije. Biološki test ekstrakta na Escherichia Coli kulture pokazuje da nema nikakvog uticaj na biološku aktivnost Escherichia coli i može se bezbedno primeniti bez štetnog efekta na sanaciju postrojenja.

Ključne reči: Ocimum Basilicum, EDX -SEM, sanitarna postrojenja, Escherichia coli.

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Branimir N. Grgur1*, Milica M. Gvozdenović1,
Branimir Z. Jugović2

1University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia, 2Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604597G

Zastita Materijala 57 (4)
597 – 599  (2016)

The influence of light on corrosion of polyaniline coated mild steel

Abstract

The influence of light of the mild steel corrosion in 3% NaCl solution with polyaniline coating based on the possibilities that polyaniline can generate photoelectrons, even in the laboratory conditions has been investigated.

Keywords: mild steel; corrosion; polyaniline; photoelectrochemistry.

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Uticaj osvetljenosti na koroziju mekog čelika sa prevlakom polianalina  

Izvod

Ispitivan je uticaj svetlosti na koroziju mekog čelika sa prevlakom polianilina u 3% rastvoru NaCl sa pretpostavkom da polianilin može generisati fotoelektrone čak i u uslovima laboratorijskog osvetljenja.

Klјučne reči: meki čelik; korozija; polianilin; fotoelektrohemija.

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Karmina Miteva1*, Slavčo Aleksovski1,
Gordana Bogoeva-Gaceva1,2

1Ss ”Cyril and Methodius” University in Skopje, Faculty of Technology and Metallurgy, Skopje, Republic of Macedonia, 2Research Center for Environment and Materials, Macedonian Academy of Sciences and Arts, Skopje, Macedonia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604600M

Zastita Materijala 57 (4)
600 – 604  (2016)

Catalytic pyrolysis of waste plastic into liquid fuel 

Abstract

Process of pyrolysis is a thermochemical process conducted at high temperatures and usually in presence of catalysts. Different type of catalysts, natural and synthetic, can be used for conversion of organic wastes into valuable fuels. The aim of this work is conversion of waste polyolefin mixture and production of liquid fuel using mixture of Al2O3 and SiO2 as a catalyst. Waste mixture was pyrolyzed at temperature range 400-550oC and obtained products were liquid fuel, gas and minor solid residue. Under the optimized reaction conditions, the condensed liquid fraction is much larger than the gaseous fraction. Different amounts of catalyst and polyolefin mixture as a feedstock were used. According to the obtained results, the retention time and the percent of SiO2 in the catalyst mixture have predominant effect on the amount of liquid product. Decreasing the quantity of SiO2 in the catalyst mixture increased the yield of liquid product. The physical properties of obtained liquid products were characterized and according to the measured values, liquid fuel belongs to light fraction of diesel fuel.

Keywords: Pyrolysis, waste plastic, catalytic conversion, fuel, physical properties.

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Katalitička piroliza otpadne plastike u tečno gorivo

Izvod

Proces pirolize je termohemijski postupak koji se izvodi na visokim temperaturama i obično u prisustvo katalizatora. Različite vrste katalizatora, prirodnih i sintetičkih, može se koristiti za konverziju iz organskog otpada u vredna goriva. Cilj ovog rada je konverzija otpada poliolefinske mešavine u proizvodnju tečnih goriva, koristeći mešavinu Al2O3 i SiO2 kao katalizator. Mešavina otpada je podvrgnuta procesu pirolize u temperaturnom opsegu 400-550oC i dobijeni proizvodi su tečno gorivo, gas i malo čvrsti ostatak. Pod optimalnim reakcionim uslovima, kondenzovana tečna frakcija je mnogo veća od gasovite frakcije. Korišćene su različite količine katalizatora i poliolefinske mešavine kao sirovine. Prema dobijenim rezultatima, retenciono vreme i procenat SiO2 u katalizatorskoj smeši imaju dominantan uticaj na iznos tečnog proizvoda. Smanjenje količine SiO2 u smeši katalizatora poveća prinos tečnog proizvoda. Fizičke osobine dobijenih tečnih proizvoda su okarakterisane po izmerenoj vrednosti. Tečno gorivo spada u lake frakcije dizel goriva.

Ključne reči: piroliza, otpadna plastika, katalitička konverzija, gorivo, fizička svojstva.

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Abdusalam Drah1, Jelena D. Rusmirović2, Milena Milošević1, Mustafa Kalifa1, Ivana Stojiljković3, Milica Rančić3, Aleksandar D. Marinković1*

1University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia, 2University of Belgrade, Innovation center, Faculty of Technology and Metallurgy, Belgrade, Serbia, 3University of Belgrade, Faculty of Forestry, Belgrade, Serbia

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604605D

Zastita Materijala 57 (4)
605 – 612  (2016)

Techno-economic analysis of unsaturated polyester production from waste PET

Abstract

Unsaturated polyester resins (UPe) were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate (PET) depolymerization with dipropylene glycol (DPG) in the presence of tetrabutyl titanate catalyst. Waste PET glycolyzed product and UPes were characterized by FTIR and NMR spectroscopy, elemental analysis, acid value (AV), hydroxyl value (HV) and iodine value. Nanocomposites, based on unsaturated polyester resins and hexamethyldisilazane modified silica nanoparticles, were prepared with intention to show one of valuable applicative commercialization of UPe resin. In order to determine potential of the possible implementation of developed new technology for UPe production some aspect of techno-economic analysis was analyzed.  Economic potential/benefit and process profitability of the presented technology was based on the use of recycled raw input materials, i.e. waste PET, which is one of the most effective ways to save natural resources, protect the environment, and save money. Principles of green economy was incorporated in the results of developed UPe production technology which is related to both environmental protection and profitability achievement with no additional negative impact to environment, i.e. pollution decrease without negative effect of implemented technology.

Keywords: unsaturated polyester, modified silica, nanocomposite, profitability, green economy

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Tehno-ekonomska analiza proizvodnje nezasićenih poliestera izotpadnog PET-a

Izvod

Nezasićene poliestarske smole (UPe) su sintetisane iz anhidrida maleinske kiseline i proizvoda glikolize, dobijenih depolimerizacijom poli(etilen tereftalata) (PET-a) sa dipropilen-glikolom (DPG) u prisustvu tetrabutil-titanata kao katalizatora. Proizvod glikolize otpadnog PET-a i UPe smole su okarakterisani pomoću FTIR i NMR spektroskopije, elementalne analize, kiselinskog (AV), hidroksilnog (HV) i jodnog broja. Nanokompoziti, bazirani na nezasićenim poliestarskim smolama i nanočesticama silicijum-dioksida modifikovanim heksametildisilazanom, pripremljene su sa namerom da se prikaže jedna od značajnih komercijalnih primena UPe smola. U cilju određivanja mogućnosti mogućih implementacija razvijenih novih tehnologija proizvodnje UPe smola,  urađena je neki tehno-ekonomska analiza.  Ekonomska korist i profitabilnost procesa prikazane tehnologije su zasnovani na primeni reciklaže sirovog materijala, otpadnog PET-a, što predstavlja jedan od najefektivnijih načina da se očuvaju prirodni resursi, zaštiti životna sredina i uštedi novac. Principi zelene ekonomije su ugrađeni u razvijenoj tehnologiji proizvodnje UPe smola, što se odnosi i na zaštitu životne sredine i dostizanje profitabilnosti bez dodatnih negativnih uticaja na životnu sredinu, odnosno na smanjenje zagađenja bez negativnog uticaja na implementiranu tehnologiju.

Ključne reči: nezasićene poliestarske smole, modifikovani silicijum-dioksid, nanokompoziti, profitabilnost, zelena ekonomija.

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Jagoda Radošević1, Petar Ljumović1*,
Antonija Višekruna2

1University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia, 2Aluminij d.d. Mostar, Mostar, BiH

Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
UDC:620.162/.163.oo1.5
doi:10.5937/ZasMat1604613R

Zastita Materijala 57 (4)
613 – 622  (2016)

Properties of Al – Ga alloys during cathodic polarization in NaF solution

Abstract

In this paper, the electrochemical properties of high – purity aluminium with the addition of small amounts of gallium at high cathodic potentials have been investigated. The anodic current was followed through time in order to determine the quantity of charge needed for the formed substances oxidation. Anodic current responses for the period of 1 s were recorded. Time responses for the cathodic and anodic currents were recorded and showed in characteristic diagrams. The range of low and high cathodic potentials (LCP, HCP) was defined for all samples. For the experimental work, standard electrochemical cell with saturated calomel electrode (SCE) and platinum counter electrode were used. The solution 2 M NaF was used for this work.

Keywords: Al-Ga alloy, Cathodic polarization, Aluminium activation, NaF solution, Hydration potential.

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Svojstva Al – Ga legure tokom katodne polarizacije u rastvoru NaF

Izvod

U ovom radu analizirana su elektrokemijska svojstva superčistog aluminija uz dodatak malih količina galija pri visokom katodnom potencijalu. Potencijal anode je praćen u vremenu, u cilju određivanja količine naboja potrebnog za oksidaciju nastalih supstanci. Odgovori anodnih potencijala su bilježeni u vremenu od 1 sekunde. Vremenski odgovori za katodni i anodni potencijal snimani su i prikazani karakterističnim dijagramima. Raspon niskih i visokih katodnih potencijala (LCP, HCP) definiran je za sve uzorke. U eksperimentalnom radu korištena je standardna elektrokemijska ćelija sa zasićenom kalomel elektrodom (SCE) uz protuelektrodu od platine. Otopina korištena u radu je 2 M NaF.

Ključne riječi: Legura Al-Ga, katodna polarizacija, aktivacija aluminija, otopina NaF, potencijal hidratacije.

 

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