JOURNAL OF ENGINEERING & PROCESSING MANAGEMENT

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UPRAVLJANJE HEMIJSKIM I MIKROBIOLOŠKIM KVALITETOM VODE U BAZENIMA ZA KUPANJE I REKREACIJU Article  in  JOURNAL OF ENGINEERING & PROCESSING MANAGEMENT · February 2017 DOI: 10.7251/JEPMSR1608091A

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Volume 8, No. 1, 2016 _____________________________________________________________________________________

JOURNAL OF ENGINEERING & PROCESSING MANAGEMENT An International Journal

Supported by Ministry of Science and Technology of Republic of Srpska and Academy of Science and Arts of Republic of Srpska

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Name of Journal/Naziv časopisa: Journal of Engineering & Processing Management Editors/Urednici: Prof. Miladin Gligorić, co-editor Prof. Mitar Perušić, co-editor Technical Editor/Tehnički urednik: M.Sc. Danijela Rajić M.Sc. Marija Riđošić Editorial board/Uređivački odbor: Prof. Miladin Gligorić, University of East Sarajevo, Faculty of Technology Zvornik, RS, B&H Prof. Mitar Perušić, University of East Sarajevo, Faculty of Technology Zvornik, RS, B&H Prof. Miomir Pavlović, University of East Sarajevo, Faculty of Technology Zvornik, RS, B&H Prof. Milovan Jotanović, University of East Sarajevo, Faculty of Technology Zvornik, RS, B&H Prof. Andrzej Kowal, Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland, Prof. Vladimir Srdić, Universty of Novi Sad, Faculty of Technology, Serbia Prof. Zdravko Krivokapić, University of Podgorica, Faculty of Mechanical Engineering, Montenegro Prof. Svetomir Hadži Jordanov, University “St. Kiril and Metodij” Skopje, Faculty of Technology and Metallurgy, Macedonia Prof. Ivan Krastev, Institute of Physical Chemistry, Bulgarian Academy of Sciences, Bulgaria Prof. Regina Fuchs-Godec, University of Maribor, Faculty of Chemistry and Chemical Engineering, Slovenia Prof. Ivan Esih, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Croatia. Publisher/Izdavač: University of East Sarajevo, Faculty of Technology Zvornik, Republic of Srpska, Bosnia & Herzegovina For publisher/ Za izdavača: Prof. Miladin Gligorić, Dean Number of copies/Tiraž: 300 Journal of Engineering & Processing Management Karakaj bb, 75 400 Zvornik Republic of Srpska, Bosnia & Herzegovina + 387(56) 261 072 + 387(56) 260 190 [email protected] www.journalepm.org ____________________________________________________________________________________

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Predgovor Poštovani, cilj časopisa je prezentacija i diskusija rezultata koji su neposredno vezani za teorijske, inženjerske i menadžerske aspekte, kako u hemijskoj i procesnoj industriji, prehrambenoj industriji, tako i u metalurgiji, građevinarstvu i industriji, kao i tema iz oblasti zaštite životne sredine. Ovom prilikom pozivamo autore sa univerziteta, istraživačkih centara i industrije da uzmu učešće u narednim brojevima ovog časopisa. Uređivački odbor

Preface Dear, The main objective of the Journal is presentation and discussion of the results that are directly linked to theoretical managing and engineering aspects in chemical and processing industry, food industry as well as in metallurgy, construction and industrial finishing, also including topics related to environment and environmental protection. The authors from universities, research centres and industry are invited to submit papers and take part in future numbers of this publication. Editorial board

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CONTENTS 1.

MATERIAL AND ENERGY FLOW MANAGEMENT-LIFELONG LEARNING COURSES EXPERIENCES Z. Zavargo, A. Jokić, J. Pavličević, B. Ikonić, O. Bera

2.

ADSORPCIJA METILENSKOG PLAVOG NA AKTIVNOM UGLJENIKU DOBIJENOM OD PLODA PLATANA V. Dodevski, B. Kaluđerović, S. Krstić, Đ. Čokeša, D. Brković

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3.

ANALYTICAL STUDY OF MARBLE CONSOLIDATION BY OXALATE PRECIPITATION USING DENSITY, FTIR AND POWDER-XRD MEASUREMENTS R. Terzu, E. Baraj, S. Yu, C. Förester, H. Kropf, K. Xhaxhiu, M. Come

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ODREĐIVANJE ZAPRLJANOSTI KOTLOVSKIH TERMOENERGETSKIM POSTROJENJIMA B. Stojanović

U

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5.

ISTRAŽIVANJE ZADOVOLJSTVA KORISNIKA USLUGE U FARMACEUTSKOJ MALOPRODAJI PRIMENOM SERVQUAL MODELA S. Ćortoševa, E. Garvanska-Nečev

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6.

EFECTS OF CHEMICAL COMPOSITION ON THE MICROSTRUCTURE AND PROPERTIES OF THE Cu-Ge-Sb ALLOYS D. Gurešić, A. Đorđević, A. Marković, M. Tomović, N. Talijan, I. Manasijević

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NOVI PRILAZ ODREĐIVANJU MINIMALNE REZERVOARA ZA KOMPRIMOVAN VAZDUH M. Perušić, B. Pejović, R. Filipović, M. Smiljanić, M. Radić

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PRODUCTION OF GLASS-CERAMICS FROM WASTE MATERIALS AND OPTIMIZATIN OF THE MAIN PROCESS PARAMETERS B. Angjusheva, E. Fidancevski, K. Lisichkov, V. Jovanov

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KVALITET OTPADNIH VODA I ZAGAĐENOG VAZDUHA GALVANSKO-HEMIJSKIH PROCESA B. Arsenović, B. Ivanović

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CIJEVI

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ZAPREMINE

10. UPRAVLJANJE HEMIJSKIM I MIKROBIOLOŠKIM KVALITETOM VODE U BAZENIMA ZA KUPANJE I REKREACIJU B. Antonić, M. Gligorić, A. Došić, D. Vujadinović, R. Grujić, D. Babić

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11. SHORT OVERWIEV OF ENCAPSULATION TECHNOLOGIES FOR DELIVERY OF BIOACTIVES TO FOOD K. Trifković, G. Tadić, B. Bugarski

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Volume 8, No. 1, 2016 _____________________________________________________________________________________ Z. Zavargo, A. Jokić, J. Pavličević, B. Ikonić

DOI: 10.7251/JEPMEN1608007Z UDK: 005.6:66.012 Scientific paper

MATERIAL AND ENERGY FLOW MANAGEMENT- LIFELONG LEARNING COURSES EXPERIENCES Zoltan Zavargo1, Aleksandar Jokić1, Jelena Pavličević1, Bojana Ikonić1, Oskar Bera1 [email protected] University of Novi Sad, Faculty of Technology, Serbia

Abstract Material and energy flow management is among the most important factors for the economic growth of a society in harmony with nature and it will play the main role only in the area of sustainable development. The three lifelong learning courses were developed in order to introduce this concept to the industry professionals and administration at the city and regional level. The main goal was to heighten awareness of participants to this topic, as in Serbia it is relatively new approach in corporate and administrative management. The results of the courses confirmed the interest in this kind of lifelong learning courses with suggestion to join it in a single course with emphasise on the specific participant’s problems. Key words: lifelong learning, material and energy flow management 1. INTRODUCTION People are changing the environment, which fact is today undeniable and based on a number of evidences. The rapidity of influences on the ecosystems is increasing and the pressure on the Earth's ecosystems is reaching its limits, i.e. the point of no return. Ecosystems are characterised by constant flows and transformations of matter through a biogeochemical cycles (substance turnover or cycling of substances) such as carbon cycle, nitrogen cycle, water cycle, phosphorus cycle, etc. There is no waste in natural systems. Ecosystems are in process of a constant change, in the past driven by natural forces, but nowadays under increasing humans’ influences. The unmatched usage of resources from the environment and in the same time excessive pollutants discharge to the environment is the basic

type of connection between the environment and society. Resources and energy sources are becoming scarcer and in the same time more valuable. The highly efficient use of raw materials and energy, tied with the prevention of waste creation and loss, are becoming an imperative in future society development. Material flow analysis (MFA) is one of the different methodologies that deal with material and energy flow management in industrial and natural systems [1]. It is a depiction of physical flows (material and energy) that are related to the economy. It was adopted as a policy tool after the UN conference in Rio de Janeiro, 1992.. Material and energy flow analysis improves effectiveness of material and energy use. Integrated Pollu

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Prevention and Control Directive (IPPC Directive) requires comprehensive analyses of all energy and material flows as part of the approval of new industrial installation, and the modernisation of existing ones [2]. The Western Balkans countries, Serbia amongst them, can aspect the number of challenges on their way to the EU. One of the most pronounced is the transition of its industrial and energy systems into a renewable and sustainable sector. Difficulties are met with equivalent opportunities to phase out energy intensive structure of the society and reduce greenhouse gas emissions, save energy, reduce waste creation as well as to protect nature. By choosing for a material and energy flow analysis potential savings can be identified in industrial, regional and country level in order to establish resource and energy efficiency. The conditions in surrounding area of the Republic of Serbia, especially in the European Union, clearly show that the country needs a very deliberate and organized system of the education in the area of energy efficiency and sustainable development as one of the key conditions for the development of the Republic of Serbia towards a society based on knowledge capable to provide good employment of the population [3]. The goal of this article is to present results of the Tempus project concerning the lifelong learning (LLL) courses programme on material and energy flow management conducted at the Faculty of Technology, in Novi Sad, Serbia. 2. LLL ON MATERIAL FLOW ANALYSIS Material flow analysis is a systematic assessment of the flows and stocks of materials within a system  Industrial Material Flow Management,  Course 2: Ecosystem Management, Industrial Ecology and Zero Emission,  Course 3: Ecosystem Management Engineering Principles of Sustainable Water and Energy Management Developed lifelong learning courses have similar concept. The first part of the courses consists of short introduction to ecosystem management as a

defined in space and time [4]. MFA connects the sources and and final sinks of a material. The results of an MFA can be obtained by a simple material balance comparing all inputs, stocks, and outputs of a process. This characteristic of MFA makes it the method attractive as a decision-support tool in resource management, waste management, as well as environmental management [4]. Material flow analyses are conducted on a national, regional or city scale, but it can also be conducted along an industrial supply chain involving a number of companies. Although this is not new concept in sustainable development, its application in Serbia is sporadic and it needs to be promoted. It can be achieved through lifelong learning courses aimed to introduce this concept to industry sector as well as to public services personal and stakeholders. In the frame of higher education lifelong learning has special place. As a special form of activities within educational areas, higher education institutions will organize and implement the lifelong education following a general technological progress, the development of the area and the needs of the labour market, and lifelong learning to adapt ECTS system and it will include elements relating to non-formal education [5]. The cooperation of companies, the state and the academic sector in the areas of energy and material usage efficiency is crucial in order to develop new technologies and for effective technology transfer and their incorporation in the production systems of the Republic of Serbia. With this goal in mind at Faculty of Technology Novi Sad three lifelong learning courses are developed: 

Course

1:

Ecosystem

Management,

holistic approach to an environmental protection and sustainable development. Its main goal was to present a nature’s way to deal with material and energy flows in ecosystems. In the same time relations between society and environment were examined and possible solutions to achieve sustainable development with economic progress. The second part was different for each of courses, related to the topics of material flow analysis. The topics are: industrial ecology and zero

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emission; and engineering principles of sustainable water and energy management and industrial material flow management. At this section of the course participants are introduced to defining and understanding the flows of energy and materials through setting up material and energy balances. During the course analytical techniques and concepts for goal setting with respect to energy and material sustainability will be defined. These concepts include ecological footprint, the Natural Step, Factor 4 / Factor 10 and other assessment tools [3]. In order to obtain the objective information about the level attendee’s knowledge related to the main topic of courses and to evaluate course quality questionnaires were done prior and after the each course. The scope of this questionnaire is about exiting of knowledge on material flow analyses as well as on ecosystem management i.e. sustainable development. The participants were employees in public services, industry professionals, and stakeholders from the city and provincial level.

3. DATA EVALUATION This questionnaire consists of ten questions, which are related to the specific course content. Correct answers gained maximum points per question, while incomplete gained certain point’s fraction while false answers gained null points. Every question carries the same number of points (10), and results of the tests were expressed as percentage of whole test points. The comparative analysis of the results achieved at the introductory test and exam results of tests for each course are shown in tables 1, 2 and 3.

4. RESULTS AND DISCUSSION The results of introductory tests show a wide variety of knowledge, from very high (80.83%) to very low level (12.33%) depending on specific course topic. The highest scores of introductory test were accomplished during course 3. In the case of exam after the course better results were achieved in second group i.e. course 2. As for overall results it can be seen that best scores are achieved at introductory test for course 3, whilst best results for exam are obtained in course 2.

The results for the first part of courses related to ecosystem management showed that best results for introductory test were achieved in the third group of participants i.e. at the course 3. The results can be expected as the third group of participants was mainly made up of stakeholders at city level that are familiar with environmental problems of the region. On the other side, high scores obtained in introductory test were followed with slightly higher performance at the exam, (Table 3.). Table 1. Results at the test and exam - course 1 Topic Ecosystem management Energy efficiency and Eco-efficiency in industry Industrial Material Flow Management Fundamentals of material and energy balances Overall achievement

Test %

Exam %

36.67

95.15

33.33

93.33

32.00

99.09

12.33

81.52

38.11

92.27

It could be concluded that higher knowledge at beginning of the course prevented participants to adopt more specific information in regard to the ecosystem management. On the other hand, the biggest acquiring of new knowledge in for this topic was observed in the group that took the first course. In the case of fundamentals of material and energy balances that were covered in the all three courses results are somewhat unanticipated. In the first group mainly made up from industrial professionals lowest score was achieved only 12.33%. After the course results of the exam were significantly improved, 81.52, but still lower compared for the groups 2 and 3. Other topics related to the material flow analysis had relatively high results obtained at introductory test. The topic of industrial material flow management was reasonably well known by the industrial professionals, although in that group lowest results were achieved for fundamentals of material and energy balances. On the other hand participants of

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the third course showed highest knowledge at the introductory test. Table 2. Results at the test and exam - course 2 Topic Ecosystem management Zero Emission Concept Industrial Ecology Fundamentals of material and energy balances Overall achievement

Test %

Exam %

28.67

75.00

46.67

100.00

33.33

100.00

20.00

100.00

32.17

93.75

The third course participants were mainly from the city administration and public services. They had gain experience through other lifelong learning courses that they took part in. Table 3. Results at the test and exam - course 3 Topic Ecosystem management Sustainable Energy Management Sustainable Water Management Fundamentals of mass and energy balances Overall achievement

Test %

Exam %

80.83

85.00

62.50

91.67

45.00

88.89

63.33

87.30

60.33

88.21

At the end of each course evaluation was done. Results of the courses evaluation indicated that concluded that it would be more effective to make a general course covering the main features necessary for the adoption of the basic principles attendees were satisfied with the course content but suggestion was that these three courses should be rearranged into one with emphasize on the case studies and existing problems. The future single course would include basic theoretical features of the three previous courses with underlining real problems facing participants. In that manner more examples would be made of

specific problems those more related to attendees. The focus would be on the creation of material and energy flows in selected industry processes as well as regional balances. 5. CONCLUSION In this paper, the courses of lifelong learning from the material and energy management flows are presented. Courses were developed and held in three topics arrangement (1) The management of material flows in industry, (2) Industrial Ecology and the concept of zero emissions, and (3) engineering principles of sustainable management of water and energy. At the beginning of each course anonymous test was carried out about knowledge of course topic. At the end of the course participants are divided written materials and presentations. The first course was held for the NIS, the oil refinery in Novi Sad, the second for regional administration, Autonomous Province of Vojvodina, APV, and the third course for the administration of the City of Novi Sad. After the the course participants took the exam to evaluate their progress at selected topics. Results achieved on the exam clearly show significant improvement in knowledge compared to the beginning of the course (course 1: 38.11% test and 88.92% exam; course 2: 32.17% test and 93.75% exam; course 3: 60.33% test and 88.21% exam). As can be seen, the maximum knowledge of the introductory test is shown on the course 3 and minimum on the course 2. On examination the most knowledge has been shown on the course 2 (93.75%). Achieved knowledge of the other two courses were about the same (88.92% course 1 and course 3 88.21%). At the end evaluations courses was done. The evaluations were positive, whilst the number of proposals, and comments was minimal. It was concluded that it would be more effective to make a general course covering the main features necessary for the adoption of the basic principles of management of material and energy flows and that the next step in cooperation with the participants can result in more specific courses, tailored to their interests.

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ACKNOWLEDGMENTS This work was supported by the Tempus project 544634-TEMPUS-1-2013-1-DE-TEMPUS-JPHES, under title: International Joint Master programm on Material and Energy Flows management. REFERENCES [1] Wrisberg, N., Haes H.A., Triebswetter U., Eder P., Clift R., (2002). Analytical Tools for Environmental Design and Management in a Systems Perspective. The Combined Use of Analytical Tools, Kluwer Academic Publishers, Dordrecht, The Netherlands. [2] Directive 2008/1/EC of the European Parliament and of the Council of 15 January 2008 concerning integrated pollution prevention and control. [3] Jokić A., Zavargo Z., Ikonić B., Pavličević J., Bera O., (2015) Lifelong Learning Courses on Material and Energy Flow Management, WBCInno2015 International conference – September 18th, Novi Sad, Serbia. [4] Brunner, P.H. and Rechberger, H. (2004). Practical Handbook of Material Flow Analysis. Lewis Publishers, New York: Lewis. ISBN 1-56670-604-1. [5] Strategija Razvoja Obrazovanja u Srbiji do 2020. Godine, Sl. glasnik RS", br. 107/2012, (in Serbian).

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DOI: 10.7251/JEPMSR1608013D UDK: 66.081.3:661.183.2 Naučni rad

ADSORPCIJA METILENSKOG PLAVOG NA AKTIVNOM UGLJENIKU DOBIJENOM OD PLODA PLATANA Vladimir Dodevski1, Branka Kaluđerović1, Sanja Krstić1, Đuro Čokeša1, Danijela Brković2 [email protected] Institut nuklearnih nauka „Vinča“, Beograd, Srbija Tehnološko-metalurški fakultet, Univerzitet u Beogradu, Beograd, Srbija 1

2

Izvod Plod platana je korišćen za dobijanje praškastog aktivnog uglja. Kao aktivirajuće sredstvo u pripremi je upotrebljena koncentrovana fosforna kiselina. Izvršena je ravnotežna adsorpcija katjonske boje metilen plavo na sintetizovanom materijalu. Dobijeni rezultati su fitovani sa tri ravnotežna adsorpciona modela. Eksperimentalni rezultati su analizirani od strane Langmuir izoterme, Freundlich izoterme i Temkin izoterme. Najbolje slaganje eksperimentalnih rezultata sa teorijskim modelima je dobijeno u slučaju Langmuir-ovog ravnotežnog modela. Prema Langmuirovom modelu, postignut je najbolji adsorpcioni kapacitet boje na adsorbentu koji iznosi 354,60 mg g-1 kada je aktivan ugalj tretiran sa NaOH. Ključne reči: Adsorpcija, Metilen plavo, Platan, Aktivni ugalj

1. UVOD Boje se sastoje od molekula koji teško biološki degradiraju. Sa sve većim korišćenjem širokog spektra boja, zagađenje od boja otpadnih voda postaje veće i alarmantnije. Većina boja se raspadaju dajući opasne proizvode, kao što su ugljen monoksid, ugljen dioksid i hloridi vodonika koji redukuju prodor svetlosti fotosinteze [1]. Štaviše boje po sebi su same toksične u živom organizmu. Metilen plavo boja je katjonska boja koja ima različite primene u hemiji, biologiji, medicini i u bojnoj industriji. Široku primenu u prečišćavanju zagađenih površinskih, podzemnih i industrijskih voda ima komercijalni aktivni ugalj kao adsorbent. Karakteristiku dobrog adsorbenta ima zbog velike specifične površine, raspodele pora kao i sposobnosti

da neselektivno u značajnoj meri adsorbuje mnoge štetne sastojke iz zagađene vode [2,3]. Aktivni ugalj se može proizvesti iz velikog broja prekursora (polaznih materijala), uključujući drvo, treset, kokosovu ljusku, poljoprivredni otpad, sintetičke smole i itd. [4]. Prekursori su izloženi različitim metodama aktiviranja kao što su fizička i hemijska u pokušaju da se dobije aktivni ugalj sa visokim stepenom adsorpcije za određenu primenu. Zbog velikog zagađenja javila se potreba za uklanjanjem i smanjivanjem zagađenja. Akcenat je stavljen na adsorpcionu tehniku. Agencija za zaštitu prirodne sredine (USEPA) navela je aktivni ugalj kao jedno od najboljih sredstava za kontrolu životne zagađeno

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V. Dodevski, B. Kaluđerović, S. Krstić, Đ. Čokeša, D. Brković

Jedan od glavnih razloga korišćenja aktivnog uglja pored svojih dobrih osobina je njegova isplativost ako je u pitanju njegov alternativni način dobijanja od jeftinih polaznih sirovina [5]. Adsorpcija na aktivnom uglju ima primenu u prehrambenoj, farmaceutskoj, hemijskoj, automobilskoj, nuklearnoj industriji, itd. Primeri za to su razni filteri, prečišćivači, nosači katalizatora, baterije, kao elektrodni materijal u elektrohemiji i raznim drugim razlicitim granama industrije. Ukupna svetska proizvodnja aktivnog uglja iz 2002. godine iznosi 750.000 tona godišnje. Vodeći svetski proizvođači aktivnog uglja su : SAD, Kina, Japan i Holandija. Dobijeni aktivni ugalj se sastoji iz paralelnih ravni šestočlanih ugljeničnih prstenova koji zbog vakancija ili raznih primesa grade amorfnu strukturu [6]. Na ivicama ravni, hetero-atomi (kiseonik, vodonik, azot) poseduju funkcionalne grupe koje stupaju u međusobne interakcije ili interakcije sa odgovarajućim adsorbatom. Način aktivacije i vrsta prekursora direktno utiču na strukturu dobijenog aktivnog uglja tj. na njegovu poroznost kao i vrstu zastupljenosti funkcionalnih grupa na površini. Tretman kiselina se generalno koristi da oksiduje poroznu površinu ugljenika; da poboljša kiselu sredinu, ukloni mineralne elemente i poboljša hidrofilne površine. Površinski funkcionalne grupe konsolidovane su i unutar poroznog ugljenika. Utvrđeno je da su odgovorne za različitosti u katalitičkim i fizičko-hemijskim svojstvima ugljovodoničnih materijala [7-9]. Način aktiviranja i vrsta prekursora direktno utiču na strukturu dobijenog aktivnog uglja, na poroznost i tip funkcionalnih grupa na površini [10]. Mnogi istraživači su bili usmereni kako na izmene, kao i na karakterizaciju površinskih funkcionalnih grupa ugljenikovih materijala u cilju poboljšanja ili poboljšanja njihovih primena [11-13] Specifična površina, pore, struktura i površina hemijskih funkcionalnih grupa poroznog ugljenika određuju primenu [14-17]. Porozni ugljenik sa svojim velikim adsorpcionim sposobnostima i visokom poroznošću su u širokoj upotrebi u raznim oblastima, kao što su nosači katalizatora, elektrodni materijal za baterije, industrijsko prečišćavanje, dobijanje nanokompozita itd. [18]. Prirodni materijali kao što su pirinač [19], banana i kokosovo vlakno [20], palmino ulje [21] su

se koristili kao prekursori za dobijanje ugljenika. Struktura poroznog ugljenika se može kontrolisati na različite načine, kao što su: uslovi aktivacije (sredstvo aktivacije, temperatura i vreme), vrsta perkursora i itd. [22]. Platan (platanaceae) sadrži nekoliko vrsta drveća raspoređenih po severnoj hemisferi. Dlakavo, suvo, seme kao plod ju gusto upakovano u tvrdu drap loptu koja sadrži nekoliko stotina čekinja od kojih svaka ima jedno seme. Seme može biti prikupljeno sa drveta u jesen jer tada sazreva. Oni su jeftina i obnovljiva sirovina koja se može podići za nekoliko meseci svake godine [23]. U ovom radu, seme platana je iskorišćeno kao polazna sirovina za dobijanje aktivnog uglja pri čemu je kao aktivirajuće sredstvo korišćena fosforna kiselina. Dobijeni aktivni ugalj korišćen je kao adsorbent za uklanjanje katjonske boje metilen plavo (MP) iz vodenih rastvora. Izvršeno je određivanje adsorpcionih izotermi. 2. EKSPERIMENTALNI DEO Priprema aktivnog uglja Aktivni ugljenik je dobijen hidrotermalnom karbonizacijom ploda platana a kao aktivirajuće sredstvo je korišćena koncetrovana fosforna kiselina 85%(wt.%) za pH=1. Koncetracija rastvora je 1.333 M. Posle toga su napravljeni 0,05M rastvori: NaOH, Na2CO3 i NaHCO3. Jedan uzorak je ostao u prvobitnom stanju, odnosno nije tertian a početna pH vrednost je 1. Po 0.5g uzorka stavljeno je u polietilenske boce i zatim je sipano 50 ml 0.05M različitog rastvora, tako da je u svakoj boci početni uzorak sa različitim rastvorom, a zatim je sve to izmešano magnetnom mešalicom pri konstantnoj brzini od 150 rpm, na sobnoj temperaturi. Nakon toga je isprano sa vodom i sušeno u sušnici na 100°C. Uzorci su pripremljeni za sorpciju bojom MP. Metilen plavo (MP) Metilen plavo (MP) je izabran kao adsorbat. Često se koristi kao adsorbat prilikom procenjivanja adsorpcionih sposobnosti novosintetisanih aktivnih ugljeva. Najviše se koristi u tekstilnoj industriji, u

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hemiji kao redoks indikator i medicini. Akutno izlaganje ovoj boji, kod čoveka može dovesti do ubrzanog rada srca, povraćanja, cianoze, žutice i nekroze tkiva [24]. Molekularna formula je C16H18N3SCl a ime po IUAPAC-u je 3.7bis(Dimethylamino)-phenothiazin-5-ium chloride. Njegova molarna masa je 319.85 (g.mol-1) i λmax(nm) = 663. Adsorpcija metilen aktivnom uglju

plavog

na

sintetisanom

Isptivanje adsorpcije MP je vršeno uravnotežavanjem po 50 mg uzoraka sintetisanog aktivnog ugljenika (netretipranog, tretiranog sa: Na2CO3; NaHCO3 i NaOH) sa po 50 cm3 rastvora MP različitih početnih koncentracija (C0 = 50 – 1000 mg dm-3 bez podešavanja pH koje je iznosilo oko 5). Adsorpciona ravnoteža MP na pripremljenim materijalima je postignut posle 24 h mešanja na mešilici pri temparaturi od 25 °C. Uravnotežena suspenzija je razdvojena na centrifuge pri broju obrtaja n=4000 min-1 u trajanju 30 min. Ravnotežne koncentracije Ce su merene na UV-VIS spektrofotometru Thermo Fisher Scientific Evolution 60S pri talasnoj dužini 665 nm. 3. REZULTATI I DISKUSIJA Adsorpcija MP na aktivnom uglju se opisuje linearizovanim adsorpcionim izotermama radi utvrđivanja po kom teorijskom modelu adsorpcije se proces odvija. Eksperimentalno dobijeni rezultati su fitovani prema sledećim linearizovanim teorijskim modelima izotermi: Langmuir-ovom, Freundlichovom i Temkin-ovom [25]. Najbolje se pokazala Langmuir-ova izoterma jer se javlja linearna zavisnost kod sva 4 ispitivana uzorka, a ostala dva modela nisu prikazana u rezultatima.

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cm3 je zapremina rastvora MP i m = 50 mg je masa adsorbenta. Tabela 1. Parametri ravnotežnog modela adsorpcije

Tretira n sa Netreti ran Na2CO 3

NaHC O3 NaOH

A

B

R

0.087 14 0.021 64 0.005 06 0.001 39

0.006 63 0.007 4 0.005 54 0.002 82

0.999 71 0.999 88 0.999 98 0.999 88

KL,d m3/g 76 342 1095 2029

qm, mg/g

SM P, m2/ g

150.82 96 135.13 51 180.50 54 354.60 99

41 6 37 2 49 7 97 7

Dobijeni laboratorijski rezultati adsorpcije MP na sintetisanom aktivnom ugljeniku su korelisani sa adsorpcionim izotermama: Langmuir-a; Freundlich-a i Temkin-a [10]. Najbolje korelacije se postižu Langmuir-ovim modelom koristeći linearizovanu Langmuir-ovu jednačinu: (2) gde je: KL Langmuir-ova konstanta; i qm (mg g-1) maksimalna količina MP koja može biti adsorbovana. Koristeći maksimalnu količinu adsorbovanog MP izvršena je procena specifične međufazne površine uzorka pokrivene sa Slika 1. Ravnotežni adsorpcioni model: Langmuirmolekulima MP prema jednačine: SMP = qm x Am x ova izoterma 0,02 x1023/MMP , gde je molekulska površina MP Am= 1,30 nm2 i molekulska masa MP MMP = 284 Ravnotežna količina MP adsorbovana na g/mol.A je odsečak sa Langmuir-ove izoterme, B je sintetisanom aktivnom ugljeniku je izračunata nagib sa Langmuir-ove izoterme, R je preciznost jednačinom (1): fitovanja Langmuir-ove izoterme, Iz tabele 1. se vidi da je najbolje rezultate pokazao aktivan ugalj tretiran sa NaOH. Površina uzorka aktivnog uglja je (1) prikazana SEM spektroskopijom. Slika 2 pokazuje morfologiju površine aktivnog uglja napravljenog od gde je C0 ( mg dm-3) početna koncentracija MP, Ce punih i šupljih štapića. Takođe, različiti oblici i ( mg dm-3) je ravnotežna koncentracija MP, V = 50 veličine štapića se mogu videti na slici. Na većim uvećanjima, pore unutar štapića mogu se lepo uočiti. 16 Journal of Engineering & Processing Management|

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pH=1 NaOH NaHCO3

165 160

Na2CO3

155 150

Transmitance %

145 140 135 130 125 120 115 110 105 100 95 90 85 4000

3000

2000

Wavenumber / cm

1000

0

-1

Slika 3. FTIR spektar uzoraka i njegove funkcionalne grupe

Slika 2. Aktivni ugljenik (plod platana) pH = 1 FTIR spektroskopija je široko korišćena za karakterizaciju površinskih grupa različitih materijala, i zbog te karakteristike je primenjena na različite vrste ugljeničnih materijala. FT-IR je korišćen kao kvalitativna metoda za određivanje hemijske strukture ugljeničnih materijala. Nije bilo lako dobiti dobar spektar jer ugalj crni materijal koji apsorbuje skoro sva zračenja u vidljivom spektru, a pikovi dobijeni su obično suma od interakcije različitih tipova grupa. Na površini hemijskih funkcionalnih grupa dobijenog aktivnog uglja su okarakterisani FT-IR spektroskopijom i rezultat je dijagram koji je prikazan na slici 3.

Slika 4. XRD uzorka pH=1 i tretiranog sa NaOH Pre svega bendovi su pronađeni, dodela na širok OH adsorpciju u rasponu plan od 3500 do 3200 cm-1 i C = o istezanje apsorpcija na 1690 cm-1. Alifatski ugljovodonik (-C-H) je na približno 2900 cm-1 i trake na 1610 cm-1 može pripisati C = C istezanju aromatičnih i furanic prstenova. Karakteristične trake zbog C-O (hidroksil, estar ili etar) vibracije istezanja su uočene u opsegu 1300-1000 cm-1, dok bend na 790 cm-1 je dobio aromatičnu C-H vezu van ravni savijanja. Sa slike 4. se vidi da je uzorak pH=1 amorfan.

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4. ZAKLJUČAK Studija je pokazala da se opisanim postupkom dobija aktivni ugalj velike specifične površine i izraženih adsorpcionih sposobnosti za uklanjanje ispitivanih katjonskih vrsta iz vodenih rastvora. Zbog pomenutih osobina i sposobnosti može se ukazati na potencijalnu upotrebu ploda platana kao lako dostupne prirodne sirovine i isplative za proizvodnju aktivnog uglja. Ispitivanjem ploda platana (aktivnog uglja) tretiranog sa NaOH utvrđeno je da se boja metilen plavo u znatno većoj meri adsorbuje u baznoj sredini zbog konkurentnog

uticaja protona pri adsorpciji, kao što se može videti iz linearne zavisnosti Langmuir-ove izoterme kao i rezultata iz tabele. Adsorpcioni kapacitet boje na adsorbentu koji iznosi 354,60 mg g-1. Zahvalnica Ovaj rad je sa projekta III 45005, koje finansira Ministarstvo prosvete, nauke i tehnološkog razvoja Republike Srbije, kojima se autori ovom prilikom zahvaljuju.

LITERATURA [1] Ould Brahima, M. Belmedani, A. Belgacema, H. Hadounb, Z. Sadaouib, Chem Eng Trans. 2014, 38, 121-126 [2] M. Momčilović, M. Purenović, M. Miljković, A. Bojić, M. Ranđelović, Hem Ind. 2011, 65, 123-129 [3] P. Chingombe, B. Saha, R.J. Wakeman, Carbon. 2005, 43, 3132-3143 [4] H.Chiang, C.Huang, P. Chiang, Chemosphere. 2002, 47, 257-265 [5] B. Sivakumar , C.Kannan, and S. Karthikeyan, Rasayan J.Chem. 2012, 5, 321327 [6] J. Pastor-Villegas, J.M. Meneses Rodriguez, J.F. Pastor-Valle, M. Garcia Garcia, J. Anal. Appl. Pyrol. 2007, 80, 507-514 [7] S. Biniak, G.Szymansk, J. Siedlewski, A. Swiatkowski, Carbon. 1997, 35, 1799-1810 [8] G. Szymansk, Karpinski Z, S. Biniak, A.Swiatkowski, Carbon. 2002, 40, 26272639 [9] MT. Izquierdo, B.Rubio, C. Mayoral, JM. Andre’s, Appl Catal B Environ. 2001, 33, 315-324 [10] S.D. Faust, O.M. Aly, Chemistry of Water Treatment, 2nd ed., Taylor and Francis, 1998, p. 134 [11] M. Izquierdo, B.Rubio, C. Mayoral, JM. Andre’s, Appl Catal B Environ, 2001, m3, 315-324

[12] J. Shim, S. Park, S. Ryu, Carbon, 2001, 39, 1635-1642 [13] C. Yin, M. Aroua, W. Daud, Sep Purif Technol. 2007,52,403-415 [14] P. Albers, K. Deller, B. M. Despeyroux, G. Prescher, A. Schafer, J. Catal. 1994, 150, 368-37 [15] M. Sevilla, C. Sanchis, E. Morallon, A. B. Fuertes, Electrochem. Acta. 2009, 54, 2234-2238 [16] H. Zhu, M. Mc Shane, M. J, J. Am. Chem. Soc. 2005,127,13448-13449 [17] A. Matilainen, M. Vieno, T. Tuhkanen, Environ. Int. 2006, 32, 324-331 [18] M. Wisniewski, A. Pacholczyk, A.Terzyk , G. Rychlicki, J. Colloid Interface Sci. 2011, 354, 891-894 [19] L. Wang, Y. Guo, B. Zou, C. Rong, X. Ma, Y. Qu, Y. Li, Z. Wang, Biores Techn. 2011, 102, 1947-1950 [20] A.J. Romero-Anaya, M.A. LilloRodenas, C. Salinas-Martinez de Lecea, A. Linares-Solano, Carbon. 2012, 50, 31583169 [21] J. Guo, A. Lua, Mater Letter. 2001, 55, 334-339 [22] S.D. Faust, O.M. Aly, Chemistry of Water Treatment, 2nd ed., Taylor and Francis, 1998, p. 134 [23] B. Kaludjerović, V. Jovanović , S. Stevanović, Ž. Bogdanov, Ultrason Sonochem. 2014, 21, 782-789

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[24] B. Hameed, A. Ahmad, K. Latiff Dyes Pigm. 2007, 75, 143-149 [25] S. Karagoz, T. Tay, S. Ucar, M. Erdem, Bioresour. Technol. 2008, 99, 6214622

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DOI: 10.7251/JEPMSR1608013D UDK: 66.081.3:661.183.2 Scientific paper

ADSORPTION OF METHYLENE BLUE DYE ON ACTIVATED CARBON OBTAINED FROM THE FRUIT OF PLANE TREES Vladimir Dodevski1, Branka Kaluđerović1, Sanja Krstić1, Đuro Čokeša1, Danijela Brković2 [email protected] Institute of nuclear sciences „Vinča“, Belgrade, Serbia Faculty of Technology and metallurgy, Belgrade University, Belgrade, Serbia 1

2

Abstract The fruit of plane trees is used to obtain the powdered activated carbon. As the activating agent is used in the preparation of concentrated phosphoric acid. Completed the equilibrium adsorption of cationic methylene blue dye in the synthesized material. These results were fitted with three adsorption equilibrium model. The experimental results were analyzed by the Langmuir isotherm, Freundlich isotherm in the Temkin isotherm. The best fit of the experimental results with theoretical models is obtained in the case of Langmuir's equilibrium models. According to the Langmuir model, achieved the best adsorption capacity of the adsorbent color which is 354.60 mg g-1 when activated carbon treated with NaOH.

Keywords: Adsorption, methylene blue, planetree, activated carbon

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R.Terzu, E. Baraj, S. Yu, C. Förester, H. Kropf, K. Xhaxhiu, M. Come

DOI: 10.7251/JEPMEN1608021T UDK: 552.46:66.066.7:543.4 Scientific paper

ANANALYTICAL STUDY OF MARBLE CONSOLIDATION BY OXALATE PRECIPITATION USING DENSITY, FTIR AND POWDER-XRD MEASUREMENTS Rihana Terzu1, Edlira Baraj2, Shun Yu2, Christiane Förester3, Holger Kropf4, Kledi Xhaxhiu1, Marsilda Come3 [email protected] University of Tirana, Department of Chemistry, Faculty of Natural Sciences, Albania 2 Department of Chemistry Faculty of Mathematical Engineering and Physics Engineering, Albania 3 Institute Soft Matter and Functional Materials, Helmholtz-Zentrum, Berlin 4 Department of Nanoscale Structures and Microscopic Analyses, Institute Applied Materials, HelmholtzZentrum, Berlin 1

Abstract Our recent study on consolidation of marble samples with the purpose of culture heritage protection occurred by periodical calcium oxalate precipitation on top of quasi parallelepipedic samples. The overall process consisting of three stages of treatment, starting with 5 % calcium acetate solution for 60 minutes at 20°C, a draining step at 70°C for 30 min, followed by a treatment with 5 % ammonium sulfate solution, it followed with the third stage which includes the treatment with 5% ammonium oxalate solution revealed a continuous density increace, determined using ethanol. As the natural samples had an initial density of 2.5871 g/cm3, it increased up to 2.6980 g/cm3 for 50 times treatments. The precipitation of oxalate on top of calcium carbonate substrate, in form of calcite, revealed two distinguished infra-red bands, at 1316 cm-1and 1624 cm-1 unsymmetrically located around the carbonate one at 1426 cm-1.The intensity of the bands was proportional to the number of treatments. The continuous surface coverage investigated in parallel by powder XRD evidenced the presence of whewellite crystallites deposited on top of calcite, and their intensity increasing as well with the number of treatments. This method exhibits a reliable oxalate coverage of marble sample surfaces which doesn’t influence considerably their water solubility. Key words: calcium oxalate, marble, precipitation, density, FTIR, X- ray powder diffraction (XRD)

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1. INTRODUCTION Marble is a material that is found constantly in the building, whether for structural purposes (columns, floors, etc.) or decorative (friezes, reliefs, statues, etc.). Marble is a noble material with a special charm and easily processed, but is sensitive to changes in natural atmospheric agents or others resulting from urban and industrial activity. Marble is formed through a process of metamorphic sedimentary rocks such as limestone and dolomite, and has a low porosity [1]. When exposed to the outside environment, these carbonate stone materials undergo wet weathering that irrevocably degrades the stone substrate. Thus to prevent the deterioration and degradation of stone as a result of erosion and weathering, is very important to choose adequate methods of conservation and protection which acknowledge the chemical and physical character of diverse stone lithotypes. An effective treatment may be considered as one that protects the carbonate materials from degradation mechanisms, while not causing any damage to the stone itself [2]. A suitable method has been identified in the use of the calcium oxalate method that imitates the natural patina observed on monuments where the underlying marble substrate is usually well conserved. In nature, this patina consists mainly of calcium oxalate which exists in two forms: monohydrate whewellite (CaC2O4·H2O) and dehydrated weddellite (CaC2O4 ·2H2O). Formation of calcium oxalate on calcareous stone has been noted to penetrate deeply in an intergranular position or along micro fracture. [2-3]. Calcium oxalate compared to calcium carbonate is less soluble in the water [4]. Consolidation is considered to be one of major conservation interventions for building stones, sculptures, decorative surface, in attempt to prevent the deterioration and degradation of stone [5]. Besides the type of product used, the consolidation action achieved depends on the treatment methodology, which to a large extent can be described using parameters such as product concentration, solvent type, application process, and contact time.The product, solvent, and concentration are in general well managed in research protocols

and reported in the published literature [6]. In our study we used three stages of treatment, starting with 5% calcium acetate solution followed by a treatment with 5% ammonium sulfate solution and 5% ammonium oxalate solution. In this way, crystallization centers are formed, which grow further as a consequence of the deposition of cations and anions present. The chemical reaction is: Ca (CH3COO)2 + (NH4)2 SO4 → CaSO4 + 2NH4 C2H3O2 CaSO4 + (NH4)2C2O4→ ↓CaC2O4 + (NH4)2SO4

(1) (2)

The precipitation of oxalate on top of calcium carbonate substrate, in form of calcite, is assessed by the Fourier transform infrared spectroscopy (FTIR). Also, the continuous surface coverage investigated in parallel by powder XRD evidenced the presence of whewellite crystallites deposited on top of calcite, revealing their intensity increasing as well with the number of treatments. This method exhibits a reliable oxalate coverage of marble sample surfaces which doesn’t influence considerably their water solubility. 2. EXPERIMENTAL 2.1. Reagents All chemicals used were of analytical grade. The necessary reactants used for treatments of samples are: Calcium Acetate; Ammonium Sulphate and Ammonium Oxalate. The marble sample from the slabs of the Tirana Cultural Centre “The Pyramid” was used. The marble samples employed in this study are cut in parallelepiped form blocs with lengths of 25 ± 1mm, widths and thicknesses of 7 mm. 2.1.1. Sample preparation

To remove the attached dust, the prepared samples were dipped in distilled water for 2-3 hours followed by drying for 6 hours at 70 °C, 6 hours at 22 Journal of Engineering & Processing Management|

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100°C and 12 hours at 125°C. While treating them by three chemical solutions (5%) [5], in order to form insoluble precipitates inside them. In our study were used three stages of treatment, starting with 5 % calcium acetate solution for 60 minutes at 200C, a draining step at 70°C, for 30 min, followed by a treatment with 5 % ammonium sulfate solution. After the application of the same draining procedure as previous, it followed with the third stage which includes the treatment with 5% ammonium oxalate solution (NH4)2C2O4∙H2O, followed by the same draining procedure. One sample was left untreated to be used as blank, other samples were subject of: 10, 20, 30, 40, 50 treatments respectively, revealing each time weight increase.

be used as blank, other samples were subject of: 10, 20, 30, 40, 50 treatments respectively, revealing each time weight increas. The natural samples had aninitial density of 2.5871 g/cm3, it increased up to 2.6980 g/cm3 for 50 times treatments. Density is a direct reflection of the material porosity. During the treatments was formed oxalate on top of calcium carbonate substrate, which is more insoluble, and morphology, shinning, etc. In order to prove the assumptions from light microscopic images above, the marble samples subject of carbonate substrate, which is more insoluble, and closes the pores and material structural defects.

2.2. METHODS OF CHARACTERIZATION 2.2.1. Fourier Transforms Infrared Spectroscopy and X-Ray Powder Diffraction. In previous spectroscopic studies, the response of FT- Raman spectroscopy to the detection of nontransition metal (Groups I and II) oxalates, including calcium oxalate mono-hydrate and dihydrate and magnesium oxalate dihydrate, was assessed [7]. In this paper we used Bruker Tensor 27 FTIR to assess the precipitation of oxalate on top of calcium carbonate substrate, in form of calcite. In the present study, typically 14220 interferograms were collected covering a spectral range from 4000 to 800 cm-1 at a resolution of 4 cm-1 with standard KBr beam splitter. Interferometer: Rock Solid, Permanent aligned, high stability, Scan Speed 3 velocities, 2.2 - 20 kHz [811]. Also an analysis was made with X-Ray Powder Diffraction evidenced the presence of whewellite crystallites deposited on top of calcite. To determine the marble samples density is used the Archimedes balance which revealed a continuous density increase, determined using ethanol. 3. RESULTS AND DISCUSSION In this paper we investigated the precipitation of oxalate on top of calcium carbonate substrate, in form of calcite in the marble samples. We used three stages of treatment, one sample was left untreated to

Figure 1: Light microscope images of: (a) untreated, (b) 50X treated marble sample, taken with a 50X magnification

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R.Terzu, E. Baraj, S. Yu, C. Förester, H. Kropf, K. Xhaxhiu, M. Come

Figure 2: FT-IR spectra of natural and treated marble samples The comparison of the light microscope images of (a) untreated and (b) 50X treated marble sample, as shown by fig. 1, reveals a clear difference between them. The presence of compact oxalate crystalline layer on top of marble surface, typical for the treated sample is obvious from its visual properties, such as treatments respectively, were analyzed further by Fourier Transform Infrared Spectroscopy. FT-IR spectra of marble samples are presented in Figure 2. The presence of oxalateprecipitated on top of calcium carbonate substrate, revealed two distinguished infra-red bands, at 1316 cm-1 and 1624 cm-1 unsymmetrically located around the carbonate

one at 1426 cm-1. Further detailed investigations by powder XRD are shown in Figure 3 by comparing the measured powder patterns of natural marble (untreated) and treated samples (10X, 20X and 50X). The natural sample consists mainly of Calcite, since the calculated powder pattern (lowest diffratogramme) fits well with powder pattern of the natural marble sample. A better overview of it is exhibited in figure 4. As a consequence of the sample treatments as described above, oxalate monohydrate (whewellite) crystals are formed as shown by the additional reflections compared to the natural sample.

Figure 3: XRD patterns of the natural and treated marble samples compared to the calculated Calcite pattern

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R.Terzu, E. Baraj, S. Yu, C. Förester, H. Kropf, K. Xhaxhiu, M. Come

The intensity of the reflections is proportional to the quantity of oxalate formed, therefore proportional to the number of treatments. This method exhibits a

reliable oxalate coverage of marble sample surfaces which doesn’t influence considerably their water solubility.

Figure 4: Comparison of the measured powder sample of natural marble and calculated diffraction pattern of Calcite from ICSD data. 4. CONCLUSIONS Prevention of the deterioration and degradation of stone as a result of erosion and weatheringhas been the objective of this study. The marble sample from the slabs of the Tirana Cultural Centre “The Pyramid” was used. The marble samples consolidation is done in three stages treatment with chemical solutions (5%) in order to form insoluble precipitates inside them. All samples were subject of: 10, 20, 30, 40, and 50 treatments. In this way, crystallization centers are formed, which grow further as a consequence of the deposition of cations and anions present. After each treatment we used the Archimedes balance which revealed a continuous density increase, determined using ethanol.The natural samples had an initial density of 2.5871 g/cm3, it increased up to 2.6980 g/cm3 for 50 times treatments. Calcium oxalate formed inside pores is highly insoluble; its solubility in water at a temperature of 13°C is 0.00067 g/100 g water [12]. Methods of characterization are FTIR, Xray powder diffraction (XRD). Through of FTIR we investigated the precipitation of oxalate on top of

calcium carbonate substrate, in form of calcite and with X-ray powder diffraction (XRD) evidenced the presence of whewellite crystallites deposited on top of calcite, where their intensity increased as well with the number of treatments. With this method we confirmed that by increasing of the number of chemical treatments an overall reduction of the marble sample porosity can be achieved as a result of the formation of the precipitate formation of calcium oxalate.

REFERENCES

[1] Royer-Carfagni, G., F., (1999). Technical Note On the thermal degradation of marble. International Journal of Rock Mechanics and Mining Sciences, 36, 119–126.

[2] Doherty, B., (2007).

Efficiency and resistance of the artificial oxalate protection treatment on marble against chemical 25 Journal of Engineering & Processing Management|

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weathering. Applied Surface Science, 253, 4477–4484.

[3] Matteini, M., (2007). Conservation of stone monuments and artifacts: new possibilities offered by the ammonium oxalate based treatment. International Meeting on Science and Technology for Cultural Heritage La Havana, Cuba. February 7th-10th.

[4] Doherty, B. (2007). Durability of the

[11]

D. Mudronja. (2013). Efficiency of applying ammonium oxalate for protectionof monumental limestone by poultice, immersion and brushing methods. Appl Phys A,11, 109–119.

[12]

Robert C. Weast. HCR Handbook of chemistry and Physics, 59-th Ed; Publisher: CRC Press, Port Huron, Michigan, United States, pp 67-187.

artificial calcium oxalate protective on two Florentine monuments. Journal of Cultural Heritage, 8,186-192.

[5] Karatasios,

I. (2009). Evaluation of consolidation treatments of marly limestones used in archaeological monuments. Construction and Building Materials, 23, 2803–2812.

[6] Ana P. Ferreira Pinto. (2011). Consolidation of carbonate stones: Influence of treatment procedures on the strengthening action of consolidants. Journal of Cultural Heritage. doi:10.1016/j.culher.2011.07.003

[7] Howell G. M. Edwards. (2003). FT-Raman spectroscopy of lichens on dolomitic rocks: an assessment of metal oxalate formation. The Royal Society of Chemistry,128, 1218– 1221.

[8] Howell G.M. Edwards.(2005). FT–Raman spectroscopic study of calcium-rich and magnesium-rich carbonate minerals. Spectrochimica Acta Part A, 61, 2273–2280.

[9] Diouri, K. (2015). Kinetics of yellow dye adsorption onto marble powder sorbents. J. Mater. Environ. Sci., 6,1,79-92. ISSN : 2028-2508.

[10]

Miriello, D.(2012). Analysis of marble statues from the San Bruno Church (Serra San Bruno, Southern Italy): provenance and degradation. Appl Phys A,106, 171–179.

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DOI: 10.7251/JEPMSR1608027S UDK: 621.184.2 Stručni rad

ODREĐIVANJE ZAPRLJANOSTI KOTLOVSKIH CIJEVI U TERMOENERGETSKIM POSTROJENJIMA Bosiljka Stojanović1

1

[email protected] RiTE Ugljevik, Ugljevik, RS-BiH

Izvod Pouzdan rad opreme je prevashodno bitan za svako postrojenje. Jedna od mjera sigurnog rada parnokotlovskih sistema je čistoća cijevi. Vrlo prihvatljiv metod određivanja zaprljanosti cijevi je metod bajcovanja. U ovom radu je opisano određivanje zaprljanosti kotlovskih cijevi u Termoelektrani Ugljevik nakon decenijskog rada postrojenja. Ključne riječi: bajcovanje, poluprsten, zaprljanost 1. UVOD Ocjene trenutnog stanja ili davanja prognoze ponašanja opreme termoenergetskih postrojenja moguće je ostvariti kroz primjenu metoda i sredstava tehničke dijagnostike. Najveći problem pri uvođenju tehničke dijagnostike u složeni tehnički sistem, kakva su parnoturbinska i parnokotlovska postrojenja je izbor metoda i instrumenata za tehničku dijagnostiku [1]. Za procjenu pouzdanosti rada parnokotlovskog postrojenja u kratkoročnom ili dugoročnom periodu su bitni naslage-inkrustacije u kotlovskim cijevima i korozija u istim.

posebno ako se vrši elektrohemijski. Bez obzira na upotrebljenu kiselinu pri bajcovanju neminovno dolazi do nagrizanja zdrave metalne površine ako se ne upotrebi određeni inhibitor [2-4]. Kotlovske cijevi imaju različite zaprljanosti (naslage) koje mogu biti rastresite, tvrde i tvrde sa šljakom. Stanje cijevi se procjenjuje određivanjem specifične zaprljanosti. Specifična zaprljanost grejnih površina (K) je količina naslaga na 1m2 površine, a izračunava se prema formuli :

2. ODREĐIVANJE ZAPRLJANOSTI CIJEVI Na metalnim površinama se često javljaju nečistoće različitiog hemisjkog sastava koje se uklanjaju i hemijskim putem. Dobro poznata metoda uklanjanja oksidnih slojeva sa površine metala je kiselinsko nagrizanje (bajcovanje). Bajcovanje se izvodi u jednom ili u više koraka zavisno od upotrebljene kiseline. Najčešće se koriste hlorovodonična u prvom koraku, a zatim smjesa fluorovodoniče i azotne kiseline u drugom koraku ili sumporna kiselina pogodna za bajcovanje u jednom koraku. Mehanizmi nagrizanja su isti bilo da se radi sa hlorovodoničnom ili sumpornom kiselinom, ali je efikasnost bajcovanja sa sumpornom kiselinom veća,

K

G (g/m2) F

(1)

gdje je : G - gubitak mase uzorka nakon bajcovanja, odnosno količina naslage (g), F - unutrašnja površina uzorka cijevi (m2)[5]. Specifična zaprljanost kotlovskih cijevi se može odrediti metodom bajcovanja, elektrohemijski.

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Najčešće se koristi katodno bajcovanje, a koje podrazumjeva prethodnu pripremu uzoraka cijevi, pripremu elektrolita i provođenje postupka bajcovanja. Priprema uzorka cijevi podrаzumjeva rezanje cijevi najmanje dužine 400-500mm, a zatim rezanje na prstenove ili poluprstenove. Pri ovim operacijama se ne smije koristiti emulzija ili mehanički uticaji jer oni dovode do odvajanja i narušavanja cjeline naslage. Spoljna površina izrezanih uzoraka cijevi se pokriva ili termootpornim, kiselootpornim lakom ili ako se bajcovanje vrši na niskim temperaturama, uzorak se može zaštiti voskom. Pripremljeni uzorak se suši do konstantne težine u eksikatoru sa žarenim kalcijum hloridom, a zatim mjeri na analitičkoj vagi tačnosti (linearnosti) ±0,2 mg. Ako se želi odrediti rastresiti sloj naslage i ukupna zaprljanost onda se rastresiti sloj skida tvrdom gumicom (za mastilo), ponovo prenese u eksikator i nakon nekog vremena ponovo mjeri.

1100C, a zatim prenesu u eksikator sa žarenim kalcijum hloridom i nakon potpunog hlađenja mjere na analitičkoj vagi. Za katodno bajcovanje uzoraka cijevi sa šljakom priprema se elektrolit 15%-tne koncentracije, elektrolit se grije na 70-800C i dodaju se stimulatori koji rastvaraju šljaku kao: 2-3%-tni vodeni rastvor amonijum bifluorid, 5%-tni vodeni rastvor acetona ili 5%-tni vodeni rastvor formalina. U ovakvim slučajevima bajcovanje se izvodi u trajanju 3-4 sata [5]. Jednostavna šema bajcovanja je prikazana na slici 1.

Masa rastresitog sloja Qp, se izračunava formulom :

Qp 

Po  P1 (g/m2) F

(2)

gdje je : Po - početna masa uzorka (g), P - masa uzorka poslije skidanja rastresitog sloja gumicom (g), F - unutrašnja površina uzorka cijevi (m2). Elektrolit se stavlja u staklenu ili polietilensku kadu, a kao elektrolit je ili 8-10%-tni vodeni rastvor sumporne kiseline uz dodatak inhibitora i olovnu anodu ili 5-10 %-tni vodeni rastvor amonijum citrata pri pH 3,0-5,0 uz grafitnu elektrodu. Uzorak cijevi se priključuje kao katoda na izvor jednosmjerne struje pomoću bakarnog provodnika i kleme. Uobičajeno je da je gustoća struje 2-5 A/dm2 tokom bajcovanja. Zavisno od procjenjene količine naslaga elektrolit se pri bajcovanju može grijati na temperaturu 60-700C, ali može se vršiti i na sobnoj temperaturi. Dužina bajcovanja ne bi trebalo da prelazi 30-40 minuta. Efektivnost skidanja naslaga se prati vizuelno, isključujući i razgledajući izvađeni uzorak cijevi iz rastvora, jednom u 10-15 minuta. Nakon bajcovanja uzorci se vade iz elektrolita, peru se destilovanom vodom i suše u sušnici na 105-

Slika 1. Pojednostavljena šema bajcovanja 3. EKSPERIMENTALNI DIO Pripremljeno je šest uzoraka kotlovskih cijevi sa međupregrijanja, (gdje je P= 36-40 bara, T=5255350C) dužine 610 mm i izrezane su na poluprstenove. Na rubu poluprstena je pripremljena navrtka, kako bi se poluprsten vijkom povezao sa bakarnim provodnikom (slika 2).

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Elektrode, olovna anoda i uzorak katoda, su uronjene u elektrolit i povezane na izvor jednosmjerne struje. Bajcovanje je vršeno na sobnoj temperaturi u toku 40 minuta pri gustini struje 4A/dm2. Zatim je električno kolo prekinuto, katoda izvađena, skinuta zaštita i odvojen vijak. Katoda je isprana sa demineralizovanom vodom, sušena u sterilizatoru 200 SSW proizvođača WIMS-elektrik, na 1100C do konstantne težine,a potom prenijeta u eksikator sa žarenim kalcijum hloridom i nakon potpunog hlađenja ponovo mjerena. Zabilježen je gubitak mase za svaki uzorak pojedinačno kao i dimenzije svakog poluprstena.

4. REZULTATI I DISKUSIJA Slika2. Uzorci cijevi, poluprstenovi, sa pripremljenim navrtkama Poluprstenovi sa formiranom navrtkom su sušeni 60 minuta u eksikatoru sa žarenim kalcijum hloridom, a zatim mjereni na analitičkoj vagi Mettler AE163 Dual range balance 0-30g (readability 0,01mg), 0160g (readability 0,1mg). Spoljašna strana poluprstenova, navrtke i vijci sve do izolacije bakarnog provodnika, je zaštićena voskom (slika 3).

Slika 3. Poluprstenovi cijevi zaštićeni voskom Pripremljen je elektrolit, 10%-tni vodeni rastvor sumporne kiseline uz dodatak 1% inhibitora urotropina (heksametilentetraamin) i olovna anoda.

Izračunata je površina cijevi izložena bajcovanju (F), a zatim zaprljanost cijevi (K)po jednačini (1). Rezultati proračuna su prikazani u tabeli 1. Tabela 1. Pregled podataka o specifičnoj zaprljanosti ispitivanih uzoraka F-površina uzorka izložena bajcovanju (m2)

G gubitak mase (g)

K– specifčna zaprljanost (g/m2)

1.

19,1540 x 10-4

0,4217

220,16

2.

19,1540 x 10-4

0,4068

212,38

3.

19,1540 x 10-4

0,3814

199,12

4.

19,1540 x 10

¯4

0,3852

201,11

5.

19,1540 x 10

¯4

0,3887

202,93

6.

19,1540 x 10¯4

0,3202

167,17

Broj uzorka

Ni na jednom uzorku cijevi nije bilo rastresitog sloja naslaga pa izračunata specifična zaprljanost predstavlja ukupnu zaprljanost cijevi. Specifična zaprljanost se kreće u intervalu 167,17 do 220,16 g/m2 što je daleko manje granične vrijednosti 300g/m2 [5]. Imajući u vidu da efektivni period rada Termoelektrane Ugljevik, od marta 1985. godine do B. Stojanović

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01.oktobra 2016. godine iznosi 170.107,03 sati, a ukupno planirani zastoji, bez neplaniranih, iznose 38.727,22 sati, zaprljanost kotlovskih cijevi je sasvim tolerantna. Ovo potvrđuje da se pri radu TE najvećim dijelom pridržavalo uputstva proizvođača o pripremi napojne vode: ukupna tvrdoća

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