The influence of conditions of forming composite coating polymer-magnetic powder on physico-mechanical properties of telecommunication optical fibers

Fеrоmаgnеtskа kоmpоzitnа prеvlаkа nа оptičkоm vlаknu оmоgućаvа idеntifikаciјu i dеtеkciјu tеlеkоmunikаciоnih оptičkih vlаkаnа/kаblоvа nаkоn njihоvоg pоlаgаnjа, primеnоm stаndаrdnih mаgnеtskih mеtоdа. U оvоm rаdu su dоbiјаnа оptičkа vlаknа sа kоmpоzitnоm fеrоmаgnеtskоm prеvlаkоm. Dеfinisаn је i оptimizоvаn prоcеsа njihоvоg dоbiјаnjа i vršеnа njеgоvа numеričkа simulаciја. Kоmpоzitnа prеvlаkа fоrmirаnа је prеvlаčеnjеm оptičkih vlаkаnа dispеrziјоm prаhоvа Bа-fеritа i SmCo5 u rаstvоru ЕVA u tоluеnu. Rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе ispitivаnа је kоrišćеnjеm mikrоskоpа sа оdbiјеnоm svеtlоšću. Аnаlizа mikrоskоpskih slikа bilа је оmоgućеnа kоrišćеnjеm sistеmа: mikrоskоp- digitаlnа kаmеrа- pеrsоnаlni rаčunаr sа оdgоvаrајućim prоgrаmоm zа kvаntifikаciјu vizuеlnih infоrmаciја. Rеzultаti dоbiјеni аnаlizоm slikе оbrаđеni su mаtеmаtičkо-stаtističkоm mеtоdоm. Ispitаn је uticај brzinе prеvlаčеnjа, kоncеntrаciје pоlimеrа i mаgnеtnоg prаhа u dispеrziјi nа rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе pоlimеr mаgnеtni prаh. Kао kritеriјum zа dеfinisаnjе unifоrmnе dеblјinе kоmpоzitnе prеvlаkе usvојеnа је nајmаnjа vrеdnоst stаndаrdnе dеviјаciје nајvеrоvаtniје vrеdnоsti prеčnikа оptičkоg vlаknа sа kоmpоzitnоm prеvlаkоm. Nа оsnоvu еkspеrimеntаlnih rеzultаtа, utvrđеnо је dа sе uticај svih istrаživаnih prоcеsnih pаrаmеtаrа nа rаvnоmеrnоst prеvlаkе, mоžе svеsti nа uticај viskоznоsti dispеrziје kојоm sе vrši prеvlаčеnjе. Ustаnоvlјеnа је оptimаlnа vrеdnоst viskоznоsti dispеrziје оd 1,20-1,24 Pas, zа ispitаni sistеm, kоја оmоgućаvа fоrmirаnjе kоmpоzitnе prеvlаkе nајrаvnоmеrniје dеblјinе. Pоtvrđеnо је dа svе prоcеsnе pаrаmеtrе: kоncеntrаciјu pоlimеrа i mаgnеtnоg prаhа, brzinu i tеmpеrаturu prеvlаčеnjа trеbа usklаditi tаkо dа sе prеvlаčеnjе оdviја dispеrziјоm čiја је viskоznоst оptimаlnа. Nа оsnоvu еkspеrimеntаlnо utvrđеnih rеоlоških јеdnаčinа zа pоnаšаnjе dispеrznоg sistеmа (prаhоvi Bа-fеritа ili SmCo5 dispеrgоvаni u rаstvоru ЕVА u tоluеnu) i pоstојеćеg mаtеmаtičkоg mоdеlа zа prеvlаčеnjе оptičkih vlаkаnа pоlimеrnоm prеvlаkоm rаzviјеn је mаtеmаtički mоdеl fоrmirаnjа kоmpоzitnе prеvlаkе nа оptičkоm vlаknu kојi је оmоgućiо numеričku simulаciјu prоcеsа prеvlаčеnjа оptičkih vlаkаnа kоmpоzitnоm prеvlаkоm. Numеričkоm simulаciјоm оmоgućеnо је ispitivаnjе uticаја vеćеg brоја prоcеsnih pаrаmеtаrа i оnih kојi nisu bili еkspеrimеntаlnо ispitivаni. Utvrđеnо је dа dеblјinа prеvlаkе nајvišе zаvisi оd gеоmеtriјskih kаrаktеristikа sistеmа zа prеvlаčеnjе. Vаlidnоst mоdеlа pоtvrđеnа је dоbrim slаgаnjеm rеzultаtа numеričkе simulаciје sа еkspеrimеntаlnim. Dоbiјеnа оptičkа vlаkаnа sа kоmpоzitnоm prеvlаkоm zаdržаvајu trаnsmisiоnа i pоbоlјšаvајu mеhаničkа svојstvа. Pri dејstvu spоlјаšnjеg јеdnоsmеrnоg i nаizmеničnоg mаgnеtnоg pоlја nа оptičkо vlаknо sа fеrоmеgnеtskоm kоmpоzitnоm prеvlаkоm nе dоlаzi dо prоmеnе u snаzi prеnеsеnе svеtlоsti. Ispitаnа оptičkа vlаknа mоgućе је kоristiti kао tеlеkоmunikаciоnа оptičkа vlаknа kоја sе mоgu lоcirаti kоrišćеnjеm mаgnеtnih mеtоdа.The ferromagnetic composite coating on optical fiber enables identification and detection of telecommunication optical fibers/cables after they have been laid down, using standard magnetic methods. In this thesis the optical fibers with composite ferromagnetic coating were obtained. The process of their synthesis was defined and optimized and numerical simulation of this process was performed. The composite coating was formed by coating optical fibers with dispersion of Ba-ferrite and SmCo5 powders in EVA solution in toluene. The coating thickness uniformity was investigated using optical microscope with reflective light. The analysis of microscope images was performed using the system: microscope - digital camera- personal computer with appropriate software for quantification of visual information. These results were evaluated using mathematical-statistic methods. The influence of coating rate, concentration of polymer and magnetic powder in dispersion on polymer-magnetic powder composite coating thickness was investigated. As criteria for defining uniform thickness of composite coating the minimal value of standard deviation of mean value of diameter of optical fiber with composite coating was established. According to experimental results it was found out that the influence of all investigated process parameters on coating uniformity ends up as the influence of viscosity of coating dispersion. For investigated system, the optimal value of viscosity of dispersion that enables forming the composite coating of the most uniform thickness was established as 1.20-1.24 Pa s. It was confirmed that all process parameters: concentration of polymer and magnetic powder and coating rate and temperature should be established in that manner that coating is performed with the evaluated optimal viscosity of dispersion. According to the experimentally estimated rheological equation for behavior of dispersed system (powders of Ba-ferrite and SmCo5 dispersed in EVA solution in toluene) and existing mathematical model for coating optical fibers with polymer coating the mathematical model of forming composite coating on optical fiber was established and enabled the numerical simulation of process of coating optical fibers with composite coating. By using numerical simulation it was possible to investigate higher number of process parameters and those that were not experimentally investigated. It was established that the coating thickness mostly depends on geometrical properties of the coating system. Validity of model was confirmed by good agreement of results obtained with numerical simulation with experimental. The obtained optical fibers with composite coating keep their transmission properties and improve mechanical. No change in the power of the propagated laser beam through the fiber optic with composite ferromagnetic coating was observed when external DC and AC magnetic fields were applied. It is possible to use the developed optical fibers as telecommunication optical fibers detectable by magnetic methods

Makroporozni kopolimer na bazi glicidilmetakrilata funkcionalizovan sa dietilentriaminom kao sorbent tekstilne boje Reactive Black 5

In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine (PGME-deta), was evaluated as Reactive Black 5 (RB5) sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%), decreasing with the increase of pH (dye removal of 24% at pH 11) after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-, pseudo-second-order, intraparticle diffusion and Mckay models). The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g(-1). The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kj mol(-1) was determined, suggesting that chemisorption was also rate-controlling.U okviru ovog rada ispitana je mogućnost korišćenja makroporoznog kopolimera glicidilmetakrilata i etilenglikoldimetakrilata funkcionalizovanog reakcijom otvaranja epoksidnih grupa sa dietilentriaminom (PGME-deta) kao sorbenta reaktivne tekstilne boje Reactive Black 5 (RB5). U šaržnim uslovima je ispitano uklanjanje RB5 iz vodenog rastvora pomoću PGME-deta, variranjem pH, vremena kontakta, mase sorbenta, početne koncentracije boje i temperature. PGME-deta je pokazao afinitet za sorpciju RB5 zbog prisustva protonovanih amino grupa koje privlače anjonske sulfonatne grupe u molekulu boje i mogućnosti stvaranja vodoničnih veza između sorbenta i sorbata. Kinetika sorpcije je analizirana pomoću četiri kinetička modela (pseudo-prvog, pseudo-drugog reda, unutarčestične difuzije i Mekej) da bi se odredilo koji model najbolje opisuje sorpciju RB5. Zapažen je izrazit uticaj pH vrednosti na sorpciju RB5, sa maksimumom na pH 2 (pri čemu je efikasnost uklanjanja boje 85%), i smanjenjem količine sorbovane boje sa povećanjem pH (količina uklonjene boje na pH 11 posle 60 min iznosi samo 24%). Izučavanjem kinetike sorpcije pokazalo se da sorpcija RB5 pomoću PGME-deta sledi kinetički model pseudo-drugog reda (PSO), sugerišući da je brzina sorpcije kontrolisana kapacitetom sorbenta i koncentracijom sorbata. Mehanizam procesa dominantno čini unutarčestična difuzija, uz manji uticaj difuzije kroz film. Ovi mehanizmi difuzije su izraženiji pri nižim temperaturama i većim koncentracijama. Langmirov model najbolje opisuje ravnotežnu izotermu, ukazujući na homogenu raspodelu aktivnih mesta na površini PGME-deta i monoslojnu sorpciju. Maksimalni sorpcioni kapacitet izračunat iz Langmirove izoterme iznosi 353 mg g-1. Zapaženo je da se brzina sorpcije povećava sa povećanjem temperature. Izračunata vrednost aktivacione energije od oko 40 kJ mol-1 potvrđuje da se radi o procesu koji dominantno kontroliše hemisorpcija

The influence of synthesis parameters on textural properties of modified Ni-based catalysts supported on magnesia for production of reducing atmosphere

Reducing gas atmosphere containing CO and H2 as processing gasses is commonly used in the metal processing industry for heat treatment of special metals. For the production of reducing atmosphere conventionally are employed nickel catalysts on various ceramic supports. Since the process takes place at high temperature, thermal stability and textural properties of catalysts are of particular interest. In this work magnesia supported nickel catalysts were synthesized. The catalyst synthesis consisted of single or successive impregnations with nitrate precursor salts of nickel and modifiers (Al, Ca and Mg), followed by thermal catalyst activation. Nickel:- modifier molar ratio was 10:1.The solid to liquid mass ratio was 1:3. The concentration of Ni in impregnation solution varied from 1.0 to 3.0 moldm-3. Mercury intrusion porosimetry was used for textural characterization since the synthesized catalysts were predominantly macroporous. The impregnation led to decrease of total pore volume, broadening and shifting of pore size distribution curve towards smaller pores. These changes were enhanced with the increase of initial concentration of Ni solution and number of successive impregnations as well as the nature of modifier. The Ni-catalyst modified with Al showed the best textural properties

Supplementary data for the article: Ilić, I.; Milutinović-Nikolić, A.; Mojović, Z.; Vuković, Z.; Vulić, P.; Gržetić, I.; Banković, P.; Jović-Jovičić, N. Oxidative Degradation of Aromatic N-Compounds Using Cobalt Containing Montmorillonite-Based Catalysts. Applied Clay Science 2020, 193, 105668. https://doi.org/10.1016/j.clay.2020.105668

Supplementary material for: [https://doi.org/10.1016/j.clay.2020.105668]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4045

Textural properties of macroporous acid modified montmorillonite nanocomposites

Macroporous crosslinked copolymer, poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and its nanocomposites with acid modified montmorillonite (WA) were synthesized by radical suspension copolymerization. Nanocomposites were obtained by introducing various amounts of WA into the reaction system. Textural properties of synthesized samples were analyzed by mercury intrusion porosimetry. The synthesized nanocomposites have significantly higher specific surface area in comparison to the copolymer. Total pore volume and the most dominant pore diameter decrease with incorporation of acid modified montmorillonite in copolymer matrix.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Uticaj modifikacije na strukturna, teksturalna i adsorpciona svojstva bentonita

Natural bentonite clay from the Bogovina locality in Serbia was Na-exchanged and modified using hexadecyll-trimethylammonium bromide as surfactant and organobentonite was obtained. The influence of modifications on the structural, textural and sorption properties of bentonite was investigated. It was estimated that modifications solely replace exchangeable cations in smectite layers, whereas other admixture minerals (quartz, calcite, feldspar) in bentonite remain unaffected. According to X-ray results the modification lead to changes in the smectite structure by either decreasing, for Na-bentonite, or increasing, for organobentonite, the interplanar spacing, d(001). The appearance of three new bands in IR spectra of HDTMA-bentonite comparing to those of raw and Na-bentonite assigned to the methylene vibrations confirmed the embedding of aliphatic cations into smectite structure. In organobentonite a significant change in textural properties was observed. In particular, specific surface area dramatically decreased while originally meso and microporous material became almost completely non-porous. Despite almost insignificant specific surface area the synthesized organobentonite due to gained organophyllity of its surface exhibits exquisite adsorption properties toward investigated textile dyes having adsorption capacity approx. 2 times higher than activated carbon.Prirodna bentonitna glina sa lokaliteta Bogovina u Srbiji je natrijumski izmenjena i modifikovana heksadeciltrimetil amonijum-bromidom kao surfaktantom, pri čemu je dobijen organobentonit. Ispitivan je uticaj modifikacije na strukturu, teksturalna i adsorpciona svojstva bentonita. Utvrđeno je da primenjeni postupci modifikacije dovode isključivo do izmene katjona u medulamelamom sloju smektita, dok modifikacija ne deluje na druge prateće minerale u bentonitu (kvare, kalcit, feldspat). Uprkos neznatnoj specifičnoj površini sintetizovani organobentonit zahvaljujući novodobijenoj organofilnosti površine pokazuje izuzetna adsorpciona svojstva prema tekstilnim bojama, imajući adsorpcioni kapacitet oko 2 puta veći od aktivnog uglja

Synthesis, Characterization and Adsorptive Properties of Organobentonites

In this paper partial and complete substitution of cations in the interlayer region of clay with different amounts of two aliphatic ammonium cations was performed with aim of synthesis of organobentonites with multipurpose adsorption properties. Domestic clay from Bogovina was submitted according to a common procedure used for the obtention of organobentonite, which comprises the following steps: grinding, sieving, Na-exchange, cation exchange and drying. The samples were characterized by X-ray diffraction and infrared spectroscopy. The incorporation of surfactant molecules into smectite structure lead to constant increase of d(001) basal spacing. IR absorption bands assigned to methyl and methylene vibrations increased with the increase of surfactant/bentonite ratio and length of aliphatic chain in surfactant molecules. Adsorptive properties of the obtained materials were in accordance with their organophylicity: the adsorption of organic dye increased while the rate of removal of Pb2+ by adsorption decreased

Supplementary data for article: Andjelković, U.; Milutinović-Nikolić, A.; Jović-Jovičić, N.; Banković, P.; Bajt, T.; Mojović, Z.; Vujčić, Z.; Jovanović, D. Efficient Stabilization of Saccharomyces Cerevisiae External Invertase by Immobilisation on Modified Beidellite Nanoclays. Food Chemistry 2015, 168, 262–269. https://doi.org/10.1016/j.foodchem.2014.07.055

The external invertase isoform 1 (EINV1) was immobilised on eight differently modified beidellite nanoclays, Modifications were composed of organo-modification with different amounts of surfactant - hexadecyl trimethylammonium cation (HDTMA), pillaring with Al/Fe containing polyhydroxy cations and acid modification of Na-enriched and pillared clays. The modified nanoclays were characterised by XRD, N-2-physisorption, SEM and FT-IR spectroscopy. The amount of bound enzyme activity was significantly influenced by the modification of beidellite ranging from 50 to remarkable 2200 U/g. Biochemical characterization was performed for five modified nanoclays showing the highest enzyme activity after invertase immobilisation. The investigation demonstrated that after immobilisation the structure and the catalytic properties of invertase were preserved, while Km values were slightly increased from 26 to 37 mM. immobilisation significantly improved thermal and storage stability of EINV1. Results indicate that beidellite nanoclays obtained by low cost modifications can be applied as a suitable support for the immobilisation of invertase. The immobilizate can be efficiently engaged in sucrose hydrolysis in batch reactor.Supplementary material for: [https://doi.org/10.1016/j.foodchem.2014.07.055]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1865

Supplementary material for the article: Marković, M.; Marinović, S.; Mudrinić, T.; Ajduković, M.; Jović-Jovičić, N.; Mojović, Z.; Orlić, J.; Milutinović-Nikolić, A.; Banković, P. Co(II) Impregnated Al(III)-Pillared Montmorillonite–Synthesis, Characterization and Catalytic Properties in Oxone® Activation for Dye Degradation. Applied Clay Science 2019, 182. https://doi.org/10.1016/j.clay.2019.105276

Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3374]Supplementary material for: [https://www.sciencedirect.com/science/article/pii/S0169131719303345?via%3Dihub#ec0005

Co(II) impregnated Al(III)-pillared montmorillonite–Synthesis, characterization and catalytic properties in Oxone® activation for dye degradation

Aluminum pillared clay was synthesized and impregnated with Co2+ (CoAP), using incipient wetness impregnation method. The obtained CoAP was characterized by chemical analysis, XRPD, SEM with EDS, XPS and low temperature N2 physisorption. By these methods the incorporation of Co2+ was confirmed in both micro and mesoporous region. The synthesized material was investigated as a catalyst in catalytic oxidation of organic water pollutants – dyes – in the presence of Oxone® (peroxymonosulfate). Oxone® is a precursor of sulfate radicals. Tartrazine was chosen as a model dye pollutant. The influence of the mass of the catalyst, temperature and initial pH was investigated. Temperature increase was beneficial for dye degradation rate. The reaction rate was the highest for initial pH values around those corresponding to neutral conditions, somewhat slower for pH 10 decolorization was significantly less expressed. Along with decolorization of tartrazine solution the formation and degradation of tartrazine catalytic oxidation products were monitored using UV–Vis spectroscopy. CoAP was found to be efficient catalyst in Oxone® induced catalytic degradation of both tartrazine and detected products of its degradation.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3375