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Investigation of the possibility of application of natural zeolite for the remediation of mercury-contaminated soil from the Idrija mine site in Slovenia : bachelor thesis
No full textU ovom završnom radu provedeno je ispiranja živom zasićenih prirodnih zeolita (PZ) prema DIN 38414 S4 normi i TCLP proceduri (postupak ispiranja s karakteristikama toksičnosti, engl. Toxicity Characteristic Leaching Procedure). U širokom rasponu pH, 3 ≤ pH o ≤ 11 uočena je minimalna desorpcija Hg(II) iz živom zasićenih zeolita, dok je značajnija uočena pri pH o =2 i pH o =12. Budući da je količina desorbirane Hg(II) prema TCLP proceduri bila veća od propisane granične vrijednosti prema TCLP proceduri (0,2 mg/L) PZ se ne može primijeniti za in situ remedijaciju. TCLP procedura primijenjena je na živom onečišćeno tlo s područja rudnika Idrija u Sloveniji s i bez dodatka PZ kako bi se procijenila potencijalna toksičnost tla. Rezultati su pokazali da je tlo izrazito onečišćeno i predstavlja potencijalnu opasnost za okoliš. Dodatak zeolita smanjio je koncentraciju ukupno eluirane Hg ali nisu postignute granične vrijednosti prema TCLP proceduri.In this bachelor thesis, the leaching test of mercury-saturated natural zeolites (PZ) was carried out according to the DIN 38414 S4 norm and the TCLP procedure (Toxicity Characteristic Leaching Procedure). In a wide pH range, 3 ≤ pH o ≤ 11, minimal desorption of Hg(II) from mercury-saturated zeolites was observed, while a more significant one was observed at pH o =2 and pH o =12. Since the amount of desorbed Hg(II) according to the TCLP procedure was greater than the prescribed criterion (0.2 mg/L), PZ can not be applied for in situ remediation. The TCLP procedure was applied to mercury-contaminated soil from the Idrija mine site in Slovenia with and without the addition of PZ in order to assess the potential toxicity of the soil. The results showed that the soil is extremely polluted and represents potential environmental hazard. The addition of zeolite reduced the concentration of total eluted Hg, but without reaching the TCLP criteria
Electrocatalytic activity of cobalt for hydrogen evolution reaction : bachelor thesis
No full textSimulirano je elektrokemijsko ponašanje kobalta u 1 M otopini NaOH u području razvijanja vodika. Simulacija struja - potencijal odgovora provedena je korištenjem računalnog programa SigmaPlot. Za vrijednosti nagiba katodnog Tafelovog pravca od -115 mV dec -1 i gustoće struje izmjene od 5,6 × 10 -6 A cm -2 modeliran je odziv kobalta pri linearnoj polarizacije te prikazan u obliku odgovarajućih grafova. Simulacija impedancijskog odziva kobalta u istom elektrolitu provedena je korištenjem računalnog programa ZView. Elektrokemijski impedancijski spektri modelirani su primjenom jednostavnog Randlesovog električnog ekvivalentnog kruga i prikazani u Nyquistovom i Bodeovom prikazu. Iz rezultata elektrokemijske impedancijske spektroskopije određeni su hrapavost elektrode, gustoća struje izmjene i nagib katodnog Tafelovog pravca.Simulation of the electrocatalytic activity of cobalt for hydrogen evolution reaction was performed in 1 M NaOH solution. The simulation of current – potential correlation was performed using the SigmaPlot program. For Tafel slope of -115 mV dec -1 and exchange current density of 5.6×10 -6 A cm -2 , a linear polarization response for cobalt was modelled. Simulation of cobalt impedance spectra in 1 M NaOH solution was also performed, using the ZView program. Electrochemical impedance spectra were modelled using Randles simple electrical equivalent circuit and presented in form of Nyquist and Bode plot. From these experimental data, electrode surface roughness, exchange current density and Tafel slope were derived
Influence of storage methods on the aromatic profile of teran wine : bachelor thesis
No full textoai:repozitorij.ktf-split.hr:ktfst_1144Vino je jedan od najstarijih prirodnih pića. To je poljoprivredno-prehrambeni proizvod koji se odlikuje složenim kemijskim sastavom. Aromatični profil vina čini niz spojeva koji pripadaju sljedećim kemijskim skupinama: esteri, aldehidi, kiseline, terpeni, antocijani, šećeri, pirazini, norisoprenoidi, katehini i sl. Na području Istre uzgaja se niz autohtonih sorti vinove loze,a jedna od značajnijih sorti je Teran. Cilj ovog rada bio je izolirati i identificirani hlapljive aromatske spojeve vina Teran iz tri proizvodne godine pri dva različita načina čuvanja (čuvanje pod morem i čuvanje u podrumu). Hlapljivi spojevi su izolirani metodom mikroekstrakcije vršnih para na čvrstoj fazi (HS-SPME) korištenjem plavog vlakna, a identificirani su vezanom tehnikom plinska kromatografija-spektrometrija masa (GC-MS). Identificirano je ukupno 14 hlapljivih spojeva iz skupine alkohola, estera, kiselina i aldehida od kojih je najzastupljeniji 3-metilbutan-1-ol.Wine is one of the oldest natural beverages. It is an agricultural food product characterized by a complex chemical composition. The aromatic profile of the wine consists of a number of compounds belonging to the following chemical groups: esters, aldehydes, acids, terpenes, anthocyanins, sugars, pyrazines, norisoprenoids, catechins, etc. In the territory of Istria, a number of autochthonous grape varieties are grown, and one of the most important varieties is Teran . The aim of this work was to isolate and identify the volatile aromatic compounds of Teran wine from three years of production under two different storage methods (storage under the sea and storage in the cellar). Volatile compounds were isolated by the method of peak vapor microextraction on solid phase (HS-SPME) using a blue fiber, and they were identified by the coupled technique of gas chromatography-mass spectrometry (GC-MS). A total of 14 volatile compounds from the group of alcohols, esters, acids and aldehydes were identified, of which 3- methylbutan-1-ol is the most abundant
Volatile compounds of Lambic beer : diplom athesis
No full textU ovom radu se provodi deskriptivna senzorska analiza, test preferencije te analiza kemijskog sastava hlapljivih spojeva u četiri različite vrste lambic piva. Hlapljivi spojevi izolirani su metodom mikroekstrakcije vršnih para na krutoj fazi (HS-SPME) korištenjem sivog i plavog vlakna te su analizirani vezanim sustavom plinska kromatografija-spektrometrija masa (GC-MS) te su dobiveni rezultati uspoređeni. Identificirani spojevi se mogu svrstat u sljedeće kemijske skupine: alkoholi, esteri i aldehidi, kiseline, ketoni i fenoli.In this paper, a descriptive sensory analysis, a preference test and an analysis of the chemical composition of volatile compounds in four different types of lambic beer are carried out. Volatile compounds were isolated by the method of peak vapor microextraction on a solid phase (HS-SPME) using gray and blue fiber and were analyzed by a coupled gas chromatography- mass spectrometry (GC-MS) system, and the obtained results were compared. The identified compounds can be classified into the following chemical groups: alcohols, esters and aldehydes, acids, ketones and phenols
Hydrothermal synthesis and characterizaton of TiO2 nanostructures : bachelor thesis
No full text: Sinteza nanostrukturiranih čestica TiO 2 u ovom radu je provedena hidrotermalnom metodom. Kao prekursor za sintezu korišten je titanijev (IV) izopropoksid (TTIP), pri čemu je metanol upotrijebljen kao otapalo. Pripravljena smjesa prebačena je u trogrlu tikvicu te je uz dokapavanje vode i refluks tijekom 3 sata pri temperaturama 80°C, 82°C i 85°C provedena sinteza TiO 2 . Nakon kristalizacije provedena je separacija krute faze te je dobiveni produkt sušen i kalciniran pri temperaturama od 500°C i 840°C. Strukturna karakterizacija pripravljenog TiO 2 provedena je primjenom difrakcije X-zraka na praškastima uzrocima (XRD) i infracrvene spektroskopije s Fourierovom transformacijom (FT-IR). Nad uzorkom su provedena mjerenja veličine i distribucije veličine čestica TiO 2 dok je morfologija određena primjenom transmisijskog elektronskog mikroskopa (TEM). Rezultati mjerenja ukazuju da je postupak sinteze nano strukturiranog TiO 2 proveden uspješno uz kristalizaciju dvije polimorfne strukturne forme i anatasa i brukita. Na TEM snimkama je uočeno da su čestice TiO 2 veličine 50-70 nm aglomerirane u čestice čije dimenzije su veće od 280 nm. Na dimenzije aglomerata ukazuju mjerenja dobivena metodom laserske difrakcije gdje se veličine kreću i do mikrometarskih dimenzija.The synthesis of nanostructured TiO 2 particles in this work was carried out using the hydrothermal method. Titanium (IV) isopropoxide (TTIP) was used as a precursor for the synthesis, while methanol was used as a solvent. The prepared mixture was transferred to a three-necked flask and TiO 2 synthesis was carried out with the addition of water and reflux for 3 hours at temperatures of 80°C, 82°C and 85°C. After crystallization, the solid phase was separated and the obtained product was dried and calcined at temperatures of 500°C and 840°C. The structural characterization of the prepared TiO 2 was carried out using powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The size and size distribution of TiO 2 particles were measured over the sample, while the morphology was determined using a transmission electron microscope (TEM). The measurement results indicate that the process of synthesis of nanostructured TiO 2 was carried out successfully with the crystallization of two polymorphic structural forms, anatase and brookite. On TEM images, it was observed that TiO 2 particles with a size of 50-70 nm are agglomerated into particles whose dimensions are greater than 280 nm. The dimensions of the agglomerates are indicated by measurements obtained by the laser diffraction method, where the sizes range up to micrometer dimensions
Stability of anthocyanins and recovery : bachelor thesis
No full textAntocijani su u vodi topljivi pigmenti koji spadaju u fenole, vrlo su važni za rast i razvoj biljaka. Upotrebljavaju se kao prirodni pigmenti u raznim industrijama, a osim toga nedavna istraživanja provedena na antocijanima pokazala su kako imaju vrlo važnu ulogu kod prevencije pojedinih bolesti jer djeluju protuupalno i antioksidacijski. Zbog toga se u posljednje vrijeme javila potreba za povećanom upotrebom antocijana. Budući da su antocijani vrlo nestabilni, to otežava njihovu ekstrakciju i čuvanje. Njihova stabilnost ovisi o mnogim faktorima poput: pH, temperature, svjetla, kopigmentacije, kisika, enzima, askorbinske kiseline, i dr. Rad sadrži informacije temeljene na nizu provedenih eksperimentalnih radova kojima se utvrdilo kakva je stabilnost antocijana pri povišenim temperaturama, različitim pH vrijednostima i svjetlu što omogućava određivanje optimalnih uvjeta za razvoj budućih proizvoda koji sadrže antocijane u cilju očuvanja njihove biološke aktivnosti te prevencije procesa degradacije. Navedene su i tehnike stabilizacije antocijana koji omogućavaju obradu i čuvanje proizvoda s visokim udjelom antocijana pri višim temperaturama i većim pH vrijednostima.Anthocyanins are water-soluble pigments that belong to the group of phenols, and are very important for the mechanisms of many plants. They are used as natural pigments in various industries. In addition, and recent research on anthocyanins has shown that they play an important role in the prevention of certain diseases, as they have anti-inflammatory and antioxidative effects. As a result, there has been an increasing demand for the use of anthocyanins. Because anthocyanins are very unstable, they are more difficult to extract and store. Their stability depends on many factors such as: pH, temperature, light, copigmentation, oxygen, enzymes, ascorbic acid and others. The thesis contains information based on a large number of experiments that confirm the stability of the anthocyanins at higher temperatures, different pH values and under the influence of light. This make it possible to determine optimal conditions for the development of future products containing anthocyanins where degradation processes are prevented. The techniques for stabilising the anthocyanins, allowing the processing of the products containing them at higher temperatures and higher pH values, are also indicated
HEADSPACE PROFILE OF THE BROWN ALGA CYSTOSEIRA COMPRESSA: COMPARISON OF DRYING METHODS : master thesis
No full textAlge su skupina pretežno vodenih, fotosintetskih autotrofnih organizama. Većina algi žive u morima i oceanima dok preostali dio predstavljaju slatkovodne alge. Na osnovu fotosintetskih pigmenata alge dijelimo na smeđe, crvene i zelene. Smeđe alge sadrže pigment fukoksantin koji je zaslužan za njihovu zelenkasto-smeđu boju. Biološki su aktivne što je rezultat prisutnosti mnogih aktivnih spojeva primjerice fukoidana, sulfatiranog polisaharida koji je smješten u staničnoj stjenci smeđih algi. Rod Cystoseira obuhvaća oko 294 vrste i jedan je od najznačajnijih u obitelji Sargassaceae (nastala spajanjem obitelji Sargassaceae i Cystoseiraceae). Alga Cystoseira compressa pripada u razred Phaeophyceae, red Fucales te u rod Cystoseira. Cilj ovog rada bio je provesti analizu vršnih para alge C. compressa upotrebom GC-MS sustava sušene na tri različita načina. Mikroekstrakcijom vršnih para na čvrstoj fazi ekstrahirane su vršne pare uzoraka na DVB/CAR/PDMS i PDMS/DVB vlaknima radi potpunijeg profila vršnih para. Usporedbom dobivenih rezultata primijećeno je da u odnosu na sušene uzorke, svježi uzorci pokazuju višu koncentraciju terpena, norizoprenoida i alifatskih zasićenih spojeva, ali manju koncentraciju alifatskih nezasićenih spojeva. Iako se ukupni postotak identificiranih isparljivih organskih spojeva nije drastično razlikovao s obzirom na tehnike sušenja, primjetne su razlike u zastupljenosti određenih skupina spojeva. Uzorak sušen u pećnici pokazuje veću zastupljenost alifatskih zasićenih spojeva i terpena u usporedbi s liofiliziranim uzorkom, dok liofilizirani uzorak ima viši udio derivata benzena. Okt-1-en-3-ol je najzastupljeniji spoj u sušenim uzorcima izoliranim s oba tipa vlakana, dok ga je u svježem uzorku ima od 1,6-2,5 puta manje. U svježem uzorku, izoliranom na DVB/CAR/PDMS vlaknu, najdominantniji spoj je bio norizoprenoid β-jonon, čija se koncentracija smanjuje 5,9 do 6,9 puta nakon procesa sušenja.Algae are a group of primarily aquatic, photosynthetic autotrophic organisms. Most algae live in seas and oceans, with the remainder being freshwater algae. Based on their photosynthetic pigments, algae are categorized into brown, red, and green types. Brown algae contain the pigment fucoxanthin, which gives them their greenish-brown color. They are biologically active, due in part to the presence of fucoidan, a sulfated polysaccharide located in the cell walls of brown algae. The genus Cystoseira includes about 294 species and is one of the most important in the Sargassaceae family. The aim of this study was to perform an analysis of the headspace volatiles of C. compressa algae using a GC-MS system, dried in three different ways. A comparison of the obtained chemical profile data revealed that, compared to dried samples, fresh samples show a higher concentration of terpenes, norisoprenoids, and aliphatic saturated compounds but a lower concentration of aliphatic unsaturated compounds. Although the overall percentage of identified volatile organic compounds did not differ drastically between different drying techniques, notable differences were observed in the representation of certain compound groups. The oven-dried sample showed higher concentrations of aliphatic saturated compounds and terpenes compared to the lyophilized sample, while the lyophilized sample had a higher proportion of benzene derivatives. Okt-1-en-3-ol was the most abundant compound in the samples dried in the shade, in the oven, and in those that were lyophilized, for both fiber types. Its concentration was 1,6 to 2,5 times lower in the fresh sample. When the DVB/CAR/PDMS fiber was used in the fresh sample, the most dominant compound was the norisoprenoid β-jonone, whose concentration decreases 5,9 to 6,9 times after the drying process
Glucosinolates profile of the plant Alliaria petiolata : diploma thesis
No full textU ovom radu izolirani su i analizirani glukozinolati ljekovite češnjače (Alliaria petiolata). Cilj rada bio je istražiti glukozinolatni profil u različitim biljnim dijelovima. Analiza je provedena prema službenoj ISO 9167-1 metodi u kojoj se analiza provodi preko desulfoglukozinolata korištenjem UHLPC-MS/MS instrumenta. Također UHLPC-MS/MS tehnika je korištena za analizu intaktnih glukozinolata prisutnih u listu. Analizirani su i razgradni produkti glukozinolata nakon autolize biljnog materijala korištenjem GC-MS. UHLPC-MS analiza desulfoglukozinolata pokazala je da su u svim biljnim dijelovima (korijen, stabljika, list, cvijet i komuška) prisutni sinigrin (1,5840 –97,5028 µmol/g) i glukotropeolin (0,0373–1,3406 µmol/g). U komuški, cvijetu i stabljici pronađen je i 4-hidroksiglukobrasicin (0,0078–1,4868 µmol/g), dok je u korijenu pronađen i 4-metoksiglukobrasicin (0,16501µmol/g) i glukosinabin u tragovima. UHPLC-MS tehnika korištena je i za analizu metanol-vodenog ekstrakta lista. Identificirana su 3 spoja, sinigrin, izoviteksin-6''-O-β-D-glukopiranozid i aliarinozid koji je pronađen samo u biljci Alliaria petiolata. GC-MS tehnika korištena je za analizu diklormetanskog ekstrakta biljnog materijala nakon autolize. Identficirano je 12 različitih spojeva među kojima nisu pronađeni razgradni produkti glukozinolata.In this work, glucosinolates from Alliaria petiolata were isolated and analyzed. The aim of the work was to investigate the profile of glucosinolates in different parts of the plant. The analysis was made according to the official ISO 9167-1 method based on the UHPLC-MS/MS analysis of desulfoglucosinolate. The UHLPC- MS/MS technique was also used for the analysis of intact glucosinolates present in the leaf. GC-MS technique was used for analyze of glucosinolate degradation products after autolysis. Sinigrin (1.5840-97.5028 mol/g) and glucotropeolin (0.0373-1.3406 mol/g) were found in all plant parts of A. petiolata using UHLPC-MS/MS analysis of desulfoglucosinolates. 4-Hydroxyglucobrassicin (0.0078-1.4868 mol/g) was found in the siliquae, flower and stem, whereas 4-methoxyglucobrassicin (0.16501 mol/g) and glucosinabin (in traces) were found in the root. The UHPLC-MS technique was also used for the analysis of the methanol-water leaf extract. Three (3) compounds were identified sinigrin, isovitexin-6''-O-β-D-glucopyranoside and alliarinoside, which was found only in Alliaria petiolata plant. The GC-MS technique was used to analyze the dichloromethane extract of the plant sample after autolysis. There were twelve (12) distinct substances found, but none of them were glucosinolate's breakdown products
Volatile compounds of goat cheese in a sack : bachelor thesis
No full textU ovom završnom radu izvršena je analiza sastava i sadržaja hlapljivih spojeva kozjeg sira iz mišine. Izolacija hlapljivih spojeva provedena je mikroekstrakcijom vršnih para na krutoj fazi korištenjem dva vlakna različitog sastava (svjetlo-plavo i sivo) pri tri različite temperature (40, 50 i 60°C). Dobiveno je ukupno šest uzoraka koji su analizirani vezanim sustavom plinska kromatografija-spektrometrija masa na HP-5MS koloni. U svim uzorcima, bez obzira na vrstu vlakna, pronađene su sljedeće klase spojeva: karboksilne kiseline, esteri, ketoni i alkoholi, s tim da su karboksilne kiseline bile najzastupljenije u svim uzorcima. Različite temperature ekstrakcije nisu značajnije utjecale na kemijski sastav i sadržaj hlapljivih spojeva.In this bachelor thesis, the composition and content of volatile compounds from the goat cheese in a sack were analyzed. Isolation of volatile compounds was performed by solid phase microextraction (HS- SPME) using two fibers of different composition (light blue and gray) at three different temperatures (40, 50 and 60°C). A total of six samples were obtained and analyzed by a coupled gas chromatography-mass spectrometry system on an HP-5MS column. In all samples, regardless of the type of fiber, the following classes of compounds were found carboxylic acids, esters, ketones and alcohols, with carboxylic acids being the most abundant in all samples. Different extraction temperatures did not significantly affect the chemical composition and content of volatile compounds
Conventional and microwave-assisted synthesis of nitrobenzene derivative of calix[4]arene : bachelor thesis
No full textOvaj završni rad uspoređuje konvencionalnu i mikrovalovima potpomognutu sintezu nitrobenzenskog derivata kaliks[4]arena. Kaliks[4]areni su kompleksne molekule s čašu-oblikom strukturom koja ima potencijal za različite kemijske aplikacije. Nitrobenzenski derivati su važni u mnogim kemijskim procesima. Istraživanje analizira utjecaj različitih uvjeta reakcije na prinos, selektivnost i brzinu sinteze u oba pristupa. Rezultati će doprinijeti boljem razumijevanju ovih procesa i njihovoj primjeni. Vrijeme sinteze uz mikrovalno zagrijavanje bilo je znatno kraće (2sata) od konvencionalne sinteze (3 dana) pri čemu je iskorištenje reakcije korištenjem mikrovalova bilo više (26,1) u odnosu na konvencionalnu sintezu (1,5%)This research paper compares conventional and microwave-assisted synthesis of nitrobenzene derivative functionalized kalix[4]arene. Kalix[4]arenes are complex molecules with a cup-shaped structure that hold potential for various chemical applications. Nitrobenzene derivatives are important in many chemical processes. The study analyzes the impact of different reaction conditions on yield, selectivity, and synthesis speed in both approaches. The results will contribute to a better understanding of these processes and their application. The synthesis time with microwave heating was significantly shorter (2 hours) than the conventional synthesis (3 days), while the utilization of the reaction using microwaves was higher (26.1) compared to the conventional synthesis (1.5%