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Theranostic potential asymmetrically substituted amide diphenylanthrancene derivative of calix(4)arene : bachelor thesis
No full textS ciljem da se ispita kompleksacijski afinitet nesimetrično supstrituiranog amidnog difenilantracenskog derivata kaliksarena 5,11,17,23-tetra-tert-butil-25-(9,10-difenilantracen-2-iloksietoksi)- 26,27,28-tris(N,N-dietil-karbamoilmetoksi)kaliks[4]arena, L, prema organskim bojama - rodaminu B, auraminu O i fluoresceinu te aktivnoj tvari – timokinonu, proveden je niz spektrofotometrijskih titracija u acetonitrilu. Određene su i konstante stabilnosti odgovarajuć ih kompleksa koje ukazuju na nastanak relativno stabilnih kompleksa derivata kaliks[4]arena L s istraživanim bojama, pri čemu je spoj L pokazao najveći afinitet prema auraminu O. S druge strane, s timokinonom nije došlo do vezanja zbog njegove strukturne nekomplementarnosti s veznim mjestom liganda. Iako kompleksu [L- fluorescein] nije bilo moguće odrediti konstantu stabilnosti, iz eksperimentalnih je podataka bio vidljiv nastanak kompleksa, te je njena vrijednost procijenjena kao niža u odnosu na odgovarajuće konstante za rodamin B i auramin O. Ispitani derivat kaliksarena demonstrirao je dobre receptorske sposobnosti veznog mjesta koje se sastoji od tercijarnih amidnih skupina i difenilantracenske skupine, pa je za očekivati da bi njegov vodotopivi analog imao velik potencijal u teranostici.In order to investigate the complexation affinity of the asymmetrically substituted amide diphenylanthracene derivative of calixarene 5,11,17,23-tetra-tert-butyl-25-(9,10-diphenylanthracene-2- yloxyethoxy)-26,27,28-tris(N,N-diethyl-carbamoylmethoxy) calix[4]arene, L, towards the organic dyes – rhodamine B, auramine O and fluorescein and the active compound – thymoquinone, a series of spectrophotometric titrations in acetonitrile were carried out. The stability constants of the corresponding complexes were determined and their values indicated that relatively stable complexes of calix[4]arene derivatives L with the studied dyes were formed, with compound L showing the highest affinity for the binding of auramine O. On the other hand, the complex with thymoquinone did not form under the experimental conditions used, due to its structural incompatibility with the ligand's binding site. Although the value of the stability constant for [L-fluorescein] complex could not be determined, there was experimental evidence of the complex formation and its value was estimated to be lower than the corresponding constants for rhodamine B and auramine O. Since the studied calixarene derivative demonstrated good receptor properties of the binding site composed of tertiary amide groups and a diphenylanthracene group, it can be expected that its water-soluble analogue should have great potential for applications in theranostics
The influence of magnesium alginate on the structure and thermal properties of poly(ethylene oxide) : bachelor thesis
No full textModifikacija svojstava poli(etilen-oksida) (PEO) provedena je magnezijevim alginatom (MgAlg) zbog smanjivanja udjela kristalne faze PEO-a čime bi se trebala poboljšati vodljivosti PEO-a. Pomoću ekstrudera s dvopužnim kontrarotirajućim vijcima uspješno su pripravljene mješavine PEO/MgAlg. Infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR) nisu potvrđene jake interakcije između PEO-a i MgAlg-a. Diferencijalnom pretražnom kalorimetrijom (DSC) istraživan je utjecaj MgAlg-a na toplinska svojstva i kristalnost PEO-a. MgAlg ima najveći utjecaj na kristalizaciju PEO-a iz taline. Udio kristalne faze PEO-a kod svih mješavina je velik i gotovo nepromijenjen u odnosu na ekstrudirani čisti PEO-u. Uočena je djelomična mješljivost mješavine PEO/MgAlg. Toplinska postojanost mješavina istraživana je neizotermnom termogravimetrijom (TG). Polimerne mješavine PEO/MgAlg razgrađuju se u tri stupnja razgradnje, a dodatkom i povećanjem udjela MgAlg-a u mješavini dolazi do smanjenja njihove toplinske postojanosti. Najveći potencijal za pripravu SPE s kalcijevim solima ima mješavina 80PEO/20MgAlg.The modification of the properties of poly(ethylene oxide) (PEO) was performed with magnesium alginate (MgAlg) due to the reduction of the crystalline phase of PEO, which should improve the conductivity of PEO. PEO/MgAlg mixtures were successfully prepared using twin-screw counter- rotating screw extruders. Fourier transform infrared spectroscopy (FTIR) did not confirm strong interactions between PEO and MgAlg. Differential scanning calorimetry (DSC) was used to investigate the influence of MgAlg on the thermal properties and crystallinity of PEO. MgAlg has the greatest influence on the crystallization of PEO. The degree of crystallinity of PEO in all mixtures is large and almost unchanged compared to pure extruded PEO. Partial miscibility of the PEO/MgAlg mixture was observed. The thermal stability of the mixtures was investigated by non-isothermal thermogravimetry (TG). Polymer mixtures of PEO/MgAlg decompose in three stages of decomposition, and the addition and increase of the proportion of MgAlg in the mixture leads to deterioration of their thermal stability. The mixture 80PEO/20MgAlg has the greatest potential for the preparation of SPE with magnesium salts
SEPARATION OF MAGNESIUM AND LITHIUM FROM SEAWATER BITTERN : bachelor thesis
No full textZbog povećane potrebe za određenim mineralima razvijaju se brojne metode za njihovo dobivanje iz gorke morske vode. Gorka morska voda predstavlja izvor za brojne minerale, a nusprodukt je proizvodnje NaCl solarnim isparavanjem u solanama. U ovom radu istražene su i analizirane dosadašnje metode odvajanja minerala litija i magnezija. Složenost odvajanja magnezija i litija iz gorke morske vode već duže vrijeme predstavlja izazov za mnoge znanstvenike. Kroz pregled literature procjenjena je učinkovitost odvajanja minerala litija i magnezija elektrodijalizom, precipitacijom, ekstrakcijom otapalom, nanofiltracijom, ionskom izmjenom i modernim procesima. Istraživanja prikazuju izazove i mogućnosti koje pruža gorka morska voda te njeno adekvatno zbrinjavanje kroz dobivanje novih minerala.Due to the increased demand for certain minerals, numerous methods for their extraction from seawater bittern are being developed. Seawater bittern is a source of numerous minerals and are produced as a by-product in the manufacture of NaCl by solar evaporation in salt pans. In this work, current methods for separating lithium and magnesium minerals were investigated and analyzed. The complexity of separating magnesium and lithium from seawater bitterns has long been a challenge for many scientists. A literature review was used to evaluate the efficiency of separating lithium and magnesium minerals by electrodialysis, precipitation, solvent extraction, nanofiltration, ion exchange, and modern techniques. The research highlights the challenges and opportunities presented by seawater bitterns and their appropriate disposal through the extraction of new minerals
Synthesis and crystal structures of cobalt(II) cordination poymers with selected halonicotinate and bispyridil ligands : master thesis
No full textPripravljeni su koordinacijski polimeri kobaltovog(II) iona s miješanim ligandima - derivatima nikotinske kiseline (6-bromnikotinska kiselina (6-BrnicH) i 6-klornikotinska kiselina (6-ClnicH)) te bispiridilnim ligandima 1,2-bis(4-piridil)etanom (1,2-bpetan) i 1,2-bis(4-piridil)etenom (1,2-bpeten). Kao otapalo korišten je N,N-dimetilformamid, DMF. Dobiveni su koordinacijski polimeri: [Co(6- BrnicH) 2 (1,2-bpetan)] n , [Co(6-BrnicH) 2 (1,2-bpeten)] n i [Co(6-ClnicH) 2 (1,2-bpeten)] n . U [Co(6-BrnicH) 2 (1,2-bpetan)] n , kobaltov(II) ion je oktaedarski koordiniran s O1 i O2 atomima karboksilata iz O,O`-kelatirajućeg 6-bromnikotinatnog liganda, s O3 i O4 atomima iz dva različita O,O`- premošćujuća 6-bromnikotinatna liganda te s piridinskim N3 i N4 atomima iz dvije različite molekule 1,2- bis(4-piridil)etana. U [Co(6-BrnicH) 2 (1,2-bpeten)] n , kobaltov(II) ion je oktaedarski koordiniran s O3 i O4 atomima karboksilata iz O,O`-kelatirajućeg 6-bromnikotinatnog liganda, s O1 i O2 atomima iz dva različita O,O`-premošćujuća 6-bromnikotintna liganda te s piridinskim N3 i N4 atomima iz dvije različite molekule 1,2-bis(4-pirdil)etena. U [Co(6-ClnicH) 2 (1,2-bpeten)] n , kobaltov(II) ion je oktaedarski koordiniran s O3 i O4 atomima karboksilata iz O,O`-kelatirajućeg 6-klornikotinatnog liganda, s O1 i O2 atomima iz dva različita O,O`-premošćujuća 6-klornikotinatna liganda te s piridinskim N3 i N4 atomima iz dvije različite molekule 1,2-bis(4-piridil)etena. Molekule 1,2-bpetana i 1,2-bpetena premošćuju kobaltove(II) ione dajući beskonačni jednodimenzijski polimerni lanac. Spojevi su karakterizirani IR spektroskopijom, termogravimetrijskom analizom (TGA) te diferencijalnom pretražnom kalorimetrijom (DSC). Kristalne strukture navedenih spojeva određene su metodom difrakcije rentgenskog zračenja na monokristalu.Cobalt(II) coordination polymers with nicotinic acid derivates (6-bromonicotinic (6-BrnicH) and 6- chloronicotinic acid (6-ClnicH)) and 1,2-bis(4-pyridyl)ethane (1,2-bpethane) and 1,2-bis(4-pyridyl)ethene (1,2-bpethene) were prepared. The solvent used was N,N-dimethylformamide, DMF. The obtained coordination polymers were [Co(6-BrnicH) 2 (1,2-bpethane)] n , [Co(6-BrnicH) 2 (1,2-bpethene)] n and [Co(6-ClnicH) 2 (1,2-bpethene)] n . In [Co(6-Br-nicH) 2 (1,2-bpethane)] n , the cobalt(II) ion is octahedrally coordinated by O1 and O2 carboxylate atoms of the O,O'-chelating 6-bromonicotinate ligand, by O3 and O4 atoms from two different O,O'-bridging 6-bromonicotinate ligand and by pyridine N3 and N4 atoms from two different molecules of 1,2-bis(4-pyridil)ethane. In [Co(6-BrnicH) 2 (1,2-bpethene)] n , the cobalt(II) ion is octahedrally coordinated by O3 and O4 carboxylate atoms of the O,O'-chelating 6-bromonicotinate ligand, by O1 and O2 atoms from two different O,O-bridging 6-bromonicotinate ligand and by pyridine N3 and N4 atoms from two different molecules of 1,2-bis(4-pyridil)ethene. In [Co(6-ClnicH) 2 (1,2-bpethene)] n , the cobalt(II) ion is octahedrally coordinated by O3 and O4 carboxylate atoms of the O,O'-chelating 6-chloronicotinate ligand, by O1 and O2 atoms from two different O,O'-bridging 6-chloronicotinate ligand and by pyridine N3 and N4 atoms from two different molecules of 1,2-bis(4-pyridil)ethene. The bridging 1,2-bpethane and 1,2-bpethene ligands connect cobalt(II) ions into infinite one-dimensional polymeric chains. The compounds were characterized by IR spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The crystal structures of these compounds were determined by the single-crystal X-ray structural analysis
ELECTROCHEMICAL BEHAVIOR OF TIN IN THE NaCl SOLUTION CONCENTRATION 0.1 mol dm-3 : bachelor thesis
No full textIspitano je korozijsko ponašanje kositra u 0,1 mol dm -3 otopini NaCl metodama linearne polarizacije u uskom i širokom području potencijala oko potencijala otvorenog strujnog kruga te metodom elektrokemijske impedancijske spektroskopije tijekom 5 sati boravka elektrode u elektrolitu. Polarizacijske krivulje analizirane su metodom ekstrapolacije Tafelovih pravaca te metodom Stern-Geary i određeni su korozijski kinetički parametri. Impedancijski spektri kositra u elektrolitu modelirani su ekvivalentnim električnim krugom s dvije vremenske konstante.Corrosion behavior of tin in 0,1 mol dm -3 NaCl solution was tested using linear polarization methods in a narrow and wide potential range around the open circuit potential and electrochemical impedance spectroscopy during 5 hours of the electrode immersion in the electrolyte. The polarization curves were analyzed using Tafel line extrapolation method and the Stern-Geary method and the corrosion kinetic parameters were determined. The impedance spectra of tin in the electrolyte are modeled by an equivalent electrical circuit with two time constants
The influence of ultrasound pulse on nucleation kinetics in batch crystallization of borax : master thesis
No full textU radu je ispitan utjecaj pulsnog ultrazvučnog djelovanja na kinetiku nukleacije kod šaržne kristalizacije boraksa u kristalizatoru s kontroliranim hlađenjem. Sva ispitivanja provodila su se u kristalizatoru laboratorijskog mjerila volumena 2,67 dm 3 . Matična otopina zasićena pri temperaturi od 30 °C hladila se brzinom od 6 °C h −1 . Prvi dio eksperimenta odnosio se na provedbu kristalizacije bez primjene ultrazvuka. Zatim se na matičnu otopinu istovremeno djelovalo primjenom mehaničkog miješanja i ultrazvuka. Ispitivanja su provedena pri brzini vrtnje miješala koja je u sustavu osiguravala stanje potpune suspenzije kristala i s amplitudom ultrazvuka od 20 % pri čemu su korištena četiri različita pulsna ultrazvučna djelovanja (20, 50, 70, 100 %). Eksperimentalni rezultati ukazuju da primjenom ultrazvuka u sustavu ranije dolazi do nukleacije. Pri svim analiziranim uvjetima nukleacija se odvija mehanizmom primarne heterogene nukleacije, a njezina brzina, kao i širina metastabilne zone se smanjuje s porastom pulsnog ultrazvučnog djelovanja. Intenziviranjem pulsnog ultrazvučnog djelovanja također se smanjuje i srednji maseni promjer finalnog kristalizacijskog produkta te sužava njegova širina raspodjele, naročito u usporedbi sa sustavom bez ultrazvuka. Pri analiziranim procesnim uvjetima intenzitet pulsnog djelovanja od p = 50 % pokazao se najpogodnijom opcijom s obzirom na to da pri tim uvjetima dobiveni kristali su izrazito pravilnog oblika, odnosno efekt sonofragmentacije nije tako izražen kao kod većih vrijednosti pulsa.The paper examines the influence of pulsed ultrasound action on nucleation kinetics in batch crystallization of borax in a crystallizer with controlled cooling. All tests were performed in a laboratory scale crystallizer with a volume of 2,67 dm 3 . The mother liquor saturated at 30 °C was cooled at a rate of 6 °C h −1 . The first part of the experiment concerned on the implementation of crystallization without the use of ultrasound. The mother liquor was then treated simultaneously with mechanical stirring and ultrasound. The tests were performed at impeller speed that ensured a complete suspension state of crystals in the system and with an ultrasound amplitude of 20 % where four different pulsed ultrasound actions were used (20, 50, 70, 100 %). Experimental results indicate that the application of ultrasound in the system leads to earlier nucleation. Under all analyzed conditions, nucleation takes place by the mechanism of primary heterogeneous nucleation, and its rate, as well as the metastable zone width, decreases with increasing pulsed ultrasound action. Intensifying the pulsed ultrasound irradiation also reduces the weight mean diameter of the final crystallization product and narrows it is span, especially in comparison with a system without ultrasound. Under the analyzed process conditions, the intensity of pulse action of = 50 % proved to be the most suitable option since the crystals obtained under these conditions are extremely regular in shape, apropos the sonofragmentation effect is not as pronounced as at higher pulse values
Seas/oceans as a sustainable mineral resource : bachelor thesis
No full textMorska/oceanska voda posljednjih desetljeća sve više zauzima vrlo bitno mjesto kao depozit i izvor mineralnih sirovina. TakoĊer sve veća potražnja za pitkom vodom i gradnja desalinizacijskih postrojenja, koji koriste tehnologiju reverzne osmoze (RO), stvaraju velike koliĉine koncentrirane slane vode (engl. brine). Koncentrirana ugušćena morska voda sadrži razliĉite ione i soli koje se mogu obnoviti, što potencijalno dovodi do ekonomske koristi i smanjenog odlaganja otpada. Pregledom literaturnih izvora u radu su prikazane metode izdvajanja iz mineralnih depozita ugušćene slane morske/oceanske vode nakon procesa desalinizacije, s posebnim osvrtom na izdvajanje magnezija.In recent decades, sea/ocean water has become increasingly important as a deposit and source of mineral resources. Also, the growing demand for drinking water and the construction of desalination plants using reverse osmosis (RO) technology have generated large quantities of concentrated brine. Concentrated seawater brine contains various ions and salts that can be recovered, resulting in economic benefits and reduced waste disposal. Using literature sources, this paper presents extraction methods from seawater brine produced in desalination plants, with particular emphasis on the extraction of magnesium
The influence of the concentration of the auxiliary electrolyte and the speed of the stirrer on the removal of the Crystal Violet dye by electrocoagulation : bachelor thesis
No full textU ovom radu korištena je metoda elektrokoagulacije (EK) za uklanjanje boje Crystal Violet (CV) iz vodenog medija korištenjem elektroda od aluminijske legure AA2007. Osnovna otopina bila je 4 mg L -1 CV (pH = 3,2) uz dodatak 1, 2 i 3 g L -1 NaCl, uz brzinu vrtnje magnetske miješalice od 100, 300 i 500 okretaja u minuti. Tijekom EK procesa, koji je trajao 50 minuta, mjerene su promjene pH, temperature, električne vodljivosti i koncentracije CV boje. Tijekom EK procesa došlo je do porasta temperature otopine kao i pH vrijednosti otopine, dok je električna vodljivost ostala gotovo konstantna. Uklanjanje boje raslo je s vremenom trajanja procesa, a najveća stopa uklanjanja (99,11%) postignuta je s 1 g NaCl i brzinom vrtnje magnetske miješalice od 100 okretaja u minuti. Utvrđeno je da tijekom EK procesa dolazi do otapanja anode i katode, što se može objasniti kemijskim otapanjem aluminijskih elektroda koje se događa zajedno s elektrokemijskim otapanjem anode. Izgled površina elektroda nakon provedenog procesa (snimljen optičkim mikroskopom) pokazuje da se anode otapaju jednoliko i lokalno tijekom EK procesa, dok su katode uglavnom podložne ravnomjernoj koroziji.In this work, the electrocoagulation method (EC) was used to remove the dye Crystal Violet (CV) from an aqueous medium using AA2007 aluminium alloy electrodes. The base solution was 4 mg L -1 CV (pH = 3.2) with the addition of 1, 2 and 3 g L -1 NaCl and with the rotation speed of the magnetic stirrer of 100, 300 and 500 rpm. During the EC process, which lasted 50 minutes, changes in pH, temperature, electrical conductivity, and CV dye concentration were measured. During the EC process, both solution temperature and pH increased, while electrical conductivity remained nearly constant. Dye removal increased with the duration of the process, and the highest removal rate (99.11%) was achieved with 1 g NaCl and a magnetic stirrer rotation rate of 100 rpm. During the EC process, anodic and cathodic material is consumed, which can be explained by the chemical dissolution of the aluminium electrodes that occurs together with the electrochemical dissolution of the anode. The appearance of the electrode surfaces (taken with an optical microscope) shows that the anodes dissolve uniformly and locally during the EC process, while the cathodes are mostly subject to uniform corrosion
Thermal stability analysis of polylactic acid/sodium alginate blend : bachelor thesis
No full textModifikacija polilaktidne kiseline (PLA) provedena je dodatkom natrijevog alginata (NaAlg) s ciljem određivanja njegovog utjecaja na toplinsku postojanost PLA. Uspješno su pronađeni optimalni uvjeti za predmiješanje PLA i NaAlg, ali i uvjeti ekstrudiranja na dvopužnom ekstruderu s kontrarotirajućim vijcima. Neizotermna termogravimetrija (TG) je primijenjena u svrhu istraživanja utjecaja NaAlg na toplinsku postojanost PLA. Polimerne mješavine PLA/NaAlg razgrađuju se u jednom stupnju razgradnje kao čisti ekstrudirani PLA. Utvrđeno je smanjenje toplinske postojanosti mješavine PLA/NaAlg koje je najznačajnije kod mješavine sa svega 2 mas.% NaAlg.The modification of polylactic acid (PLA) was carried out by adding sodium alginate (NaAlg) with the aim of determining its impact on the thermal stability of PLA. Optimal conditions were successfully identified for pre-blending PLA and NaAlg, as well as for extrusion on a twin-screw extruder with counter-rotating screws. Non-isothermal thermogravimetry (TG) was applied to investigate the influence of NaAlg on the thermal stability of PLA. The polymer blends of PLA/NaAlg undergo a one- stage degradation similar to pure extruded PLA. However, a reduction in the thermal stability of the PLA/NaAlg mixture was observed, with the most significant decrease occurring in the mixture containing only 2 wt.% NaAlg
Chemical composition of essential oils isolated from different parts of the Crithmum maritimum L. : diploma thesis
No full textPetrovac (Crithmum maritimum L.) je halofitna, samonikla biljka, rasprostranjena duž mediteranske i atlantske obale. Kroz povijest je bila poznata po svojoj kulinarskoj i medicinskoj upotrebi s obzirom na bogat sadržaj bioaktivnih spojeva i ljekovitih svojstava. Cilj ovog rada bio je izolirati eterično ulje iz različitih dijelova biljke petrovac (cvijet, list i stabljika) sakupljenih na različitim lokacijama duž Hrvatske te ispitati kemijski profil eteričnih ulja. Izolacija eteričnih ulja provedena je metodom hidrodestilacije u aparaturi po Clevengeru. Kemijski sastav ulja je potom analiziran vezanim sustavom plinska kromatografija – spektrometrija masa (GC- MS). Kao glavni sastojci eteričnog ulja, bez obzira na lokaciju i dijelove sakupljenog biljnog materijala, identificirani su monoterpeni limonen i sabinen. Ulje iz cvjetova uz glavne sastojke sadrži i α-pinen. Ulje iz listova petrovca uz dominante spojeve sadrži i γ-terpinen te terpinen-4-ol. Eterično ulje petrovca sakupljenog duž jadranske obale pripada kemotipu I ili monoterpenskom kemotipu.Sea fennel (Crithmum maritimum L.) is a halophytic, wild plant, distributed along the Mediterranean and Atlantic coasts. Throughout history, it has been known for its culinary and medicinal use due to its rich content of bioactive compounds and health-beneficial properties. The aim of this work was to isolate the essential oil from different parts of the sea fennel plant (flower, leaf and stem) collected at different locations along Adriatic coast and to examine its chemical profile. Isolation of essential oils was carried out by the method of hydrodistillation in the Clevenger apparatus. The chemical composition of the oil was then analyzed by a coupled gas chromatography-mass spectrometry (GC-MS) system. The monoterpenes limonene and sabinene were identified as the main constituents of the essential oils, regardless of the location and parts of the collected plant material. The oil from the flowers contains also α-pinene as a main ingredient. In addition to the dominant compounds, the oil from the sea fennel leaves also contains γ-terpinene and terpinen-4-ol, respectively. The essential oil of sea fennel collected along the Adriatic coast belongs to chemotype I or monoterpene chemotype