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Bioactive compounds of olive oil mill wastewater : bachelor thesis
No full textOtpadna voda koja nastaje u uljarama tijekom prerade maslina u ulje je tekućina tamno smeđe boje koju karakterizira visoki sadržaj organskih tvari među kojima treba istaknuti organske kiseline, šećere, pektine te visoki udio fenolnih spojeva. Još uvijek je u većini maslinarskih zemalja uobičajeni način zbrinjavanja ovih voda direktno odlaganje u okoliš čime se povećava negativan utjecaj na sve sastavnice okoliša. U cilju smanjenja negativnog učinka na okoliš razvijene su brojne fizikalne, kemijske, biološke te kombinirane metode obrade ovih otpadnih voda. S druge strane, ukoliko se pristupi ozbiljnoj valorizaciji ovih voda moguće ih je pretvoriti u vrlo vrijedni nusproizvod. Osobit je interes u posljednje vrijeme usmjeren na ekstrakciju bioaktivnih tvari poput fenolnih spojeva zbog njihovih antioksidativnih, antikancerogenih, protuupalnih, kardioprotektivnih i drugih pozitivnih učinaka. Upravo su zbog toga u fokusu pažnje znanstvenika radi njihove potencijalne primjene u prehrambenoj, farmaceutskoj i kozmetičkoj industriji.The wastewater produced in oil mills during the processing of olives into olive oil oil is a dark brown liquid characterized by a high content of organic substances, among which organic acids, sugars, pectins and a high proportion of phenolic compounds should be highlighted. In the most olive-growing countries, the usual way of disposing of this water is to discharge it directly into the environment, which increases the negative impact on all components of the environment. In order to reduce the negative impact on the environment, numerous physical, chemical, biological and combined methods of treating these wastewaters have been developed. On the other hand, if serious valorization of these waters is undertaken, it is possible to turn them into a very valuable by-product. Recently, special interest has been focused on the extraction of bioactive compounds such as phenolic compounds due to their antioxidant, anticancer, anti- inflammatory, cardioprotective and other positive effects. This is precisely why they are in the focus of scientists' attention due to their potential application in the food, pharmaceutical and cosmetic industries
Isolation and identification of kumquat volatile compounds : bachelor thesis
No full textU ovom završnom radu analiziran je sastav i sadržaj hlapljivih spojeva iz kore i pulpe kumkvata. Izolacija hlapljivih spojeva izvršena je mikroekstrakcijom vršnih para na krutoj fazi korištenjem tri vlakna različitog sastava (sivog, rozog i bijelog). Adsorpcija hlapljivih spojeva na vlaknima je vršena u trajanju od 40 i 80 minuta. Svi uzorci analizirani su vezanim sustavom plinska kromatografija-spektrometrija masa na HP-5MS koloni, a dobiveni rezultati su uspoređeni. U svim uzorcima najzastupljeniji spoj je D-limonen.In this bachelor thesis, the composition and content of volatile compounds from the peel and pulp of kumquat were analyzed. The isolation of volatile compounds was performed by solid phase microextraction (HS- SPME) using three fibers of different composition (gray, pink and white). Adsorption of the volatile compounds on the fibers was performed for 40 and 80 minutes. All samples were analyzed by coupled gas chromatography-mass spectrometry system on a HP-5MS column, and the results were compared. In all samples, the most abundant compound was D-limonene
THE EFFECT OF ZrO2 ON MAGNESIUM OXIDE SINTERING : bachelor thesis
No full textZahvaljujući visokom stupnju vatrostalnosti (temperatura taljenja ~2800 o C), magnezijev oksid ima znaĉajnu ulogu u proizvodnji vatrostalnih materijala. Vatrostalni materijali na bazi magnezijeva oksida kemijski su inertni na djelovanje mnogih kiselina, kiselih plinova, baznih troski i neutralnih soli, a s ugljikom reagiraju tek iznad 1800 o C. Magnezijev oksid moţe se dobiti iz razliĉitih sirovina koje se nalaze na kopnu, na primjer magnezita, dolomita i dr. Zbog smanjenja rezervi na kopnu, danas se magnezijev oksid sve više dobiva iz morske vode ili iz gorke morske vode (eng. seawater bittern) zaostale nakon izdvajanja natrijeva klorida. Ispitivanja provedena pri procesu sinteriranja pokazuju da dodatak malih koliĉina drugih materijala pozitivno utjeĉe na svojstva sinteriranog proizvoda. Na temelju dostupne literature, u ovom radu, prikazan je utjecaj dodatka cirkonijeva dioksida na svojstva konaĉnog proizvoda.Given it's high degree of heat resistance (melting point of ~2800 °C), magnesium oxide has a substantial role in the development of heat-resistant materials. Magnesium oxide-based heat-resistant materials are chemically inert when exposed to most acids, acid gasses, basic slags, and pH neutral salts. However, they react with carbon at a temperature above 1800 °C. Magnesium oxide can be obtained from different land-based raw materials such as magnesite or dolomite. Recently, given the depletion of land-based resources, the harvesting of magnesium oxide from seawater or seawater bittern, left over after the extraction of sodium chloride, is becoming a more prominent method. The latest findings show that the addition of other materials positively affects the properties of the sintered product. Based on the available literature, this paper presents the effects that adding zirconium dioxide has on the properties of sintered magnesium oxide
Influence of harmful organisms of fruit quality selected varieties of olive : bachelor thesis
No full textU ovom radu prikazani su rezultati određivanja stupnja zrelosti, težine ploda, randmana ulja i osjetljivosti istraživanih sorti (Oblica, Levantinka, Leccino i Lastovka) na štetne organizme. U razdoblju od listopada do studenog 2022. godine prikupljeni su uzorci plodova u maslinicima na dvije lokacije na području Splitsko - dalmatinske županije (Naklice i Žrnovnica). Plodovi su razvrstani prema sortimentu i vremenskom roku berbe. Od svake sorte izdvojeno je 100 plodova na kojima je provedeno istraživanje. Kod određivanja stupnja zrelosti plodovi svake sorte su razvrstani prema boji kožice. Sorta koja ima najveći postotak zrelih plodova u ranom i kasnom periodu berbe je Leccino, a najmanji postotak Lastovka što se odnosi na oba maslinika. Određivanje težine ploda je provedeno korištenjem digitalne vage. Određivanje randmana ulja je provedeno nakon prerade. Veći randman ulja je dobiven kod perioda kasne berbe na obje lokacije. U oba maslinika zabilježena je prisutnost ekonomski važnih štetnika masline: maslinine muhe (Bactrocera oleae G.) i maslinina svrdlaša (Rhynchites cribripennis D.) te prisutnost gljivičnog oboljenja (antraknoza - Gloeosporium olivarum A.). Ocjena intenziteta zaraze plodova masline provedena je vizualnim pregledom plodova. Kod oba lokaliteta, najosjetljivija sorta na napad maslinine muhe, B. oleae je Oblica dok je na napad maslinina svrdlaša R. cribripennis najosjetljivija sorta Levantinka. Rezultati istraživanja ukazuju da postoje značajne razlike u gospodarskim svojstvima masline (težina ploda, randman ulja) i osjetljivosti na štetne organizme, što potvrđuje značaj lokaliteta kao temeljne agrotehničke mjere kod odabira lokacije za podizanje maslinika.This paper presents the results of the determination of the degree of ripeness, fruit weight, randman and sensitivity of the investigated varieties (Oblica, Levantinka, Leccino and Lastovka) to harmful organisms. In the period from October to November 2022, fruit samples were collected from olive groves at two locations in Split - Dalmatia County (Naklice and Žrnovnica). The fruits were classified according to assortment and time of harvest. From each variety 100 fruits were selected and the tests were carried out. When determining the degree of ripeness, the fruits of each variety are classified according to the color of the skin. The variety with the highest percentage of ripe fruit in the early and late harvest period is Leccino, and the lowest is Lastovka, which applies to both olive groves. The weight of the fruits was determined with a digital scale. The oil content was determined after processing. At both locations, a higher oil yield was obtained in the late harvesting period. In both olive groves, the presence of economically important olive pests was detected: the olive fly (Bactrocera oleae) and the olive borer (Rhynchites cribripennis) as well as the presence of a fungal disease (anthracnose-Gloeosporium olivarum). Evaluation of the intensity of infection of the olive fruits was done by visual examination of the fruits. At both locations, the Oblica variety is most sensitive to infestation by the olive fly B. oleae, while the Levantinka variety is most sensitive to infestation by the olive borer R. cribipennis. The research results show that there are significant differences in the economic characteristics of the olive (fruit weight, oil yield) and sensitivity to environmental factors, confirming the importance of location as a basic agrotechnical measure when choosing a site for growing olive groves
SPME-GC-MS analysis of cheese in a sack : bachelor thesis
No full textU ovom završnom radu analiziran je sastav i sadržaj hlapljivih spojeva sira iz mišine. Izolacija hlapljivih spojeva izvršena je mikroekstrakcijom vršnih para na čvrstoj fazi korištenjem sivog vlakna pri tri različite temperature (40, 50 i 60°C). Dobiveni uzorci su analizirani vezanim sustavom plinska kromatografija- spektrometrija masa na HP-5MS koloni. Svi uzorci sadrže karboksilne kiseline i estere, a u svim uzorcima pronađen je i alkohol etanol.U sva tri uzorka je najveći sadržaj karboksilnih kiselina a zanimljivo je što njihov sadržaj raste sa temperaturom ekstrakcije. Ovakvi rezultati se mogu objasniti time da pri povišenoj temperaturi vjerojatno dolazi do hidrolize estera čime nastaje veći sadržaj kiselina.In this bachelor thesis, the composition and content of volatile compounds from the cheese in a sack were analyzed. Isolation of volatile compounds was performed by solid phase microextraction (HS-SPME) using gray fiber at three different temperatures (40, 50 and 60°C). The obtained samples were analyzed by coupled gas chromatography-mass spectrometry system on an HP-5MS colum. All samples contain carboxylic acids and esters and alcohol ethanol was found in all samples. All three samples have the highest content of carboxylic acids and it is interesting that their content increases with the extraction temperature. Such results can be explained by the fact that at elevated temperature ester hydrolysis is likely to occur, resulting in a higher acid content
Effect of concentration of sodium chloride solution on liquid diffusion coefficient : bachelor thesis
No full textPrijenos tvari je integralni dio brojnih procesa u kemijskom procesnom inženjerstvu. Ovisno o hidrodinamičkim uvjetima u sustavu taj prijenos se može odvijati molekularnim ili vrtložnim mehanizmom. U ovom radu se analizirala brzina prijenosa tvari isključivo molekularnim tj. difuzijskim mehanizmom. Sagledao se utjecaj koncentracije otopine natrijeva klorida, koja difundira kroz demineraliziranu vodu na vrijednost koeficijenta difuzije. Koeficijenti difuzije, čije numeričke vrijednosti daju direktan uvid u brzinu prijenosa difundirajuće tvari, u ovom slučaju određeni su eksperimentalno i primjenom jednadžbe Wilke-Changa. Rezultati eksperimentalnih mjerenja, za razliku od teorijskih, ukazuju da s povećanjem koncentracije otopine NaCl-a koeficijent difuzije poprima veću vrijednost. Eksperimentalno i teorijski određene numeričke vrijednosti tog koeficijenta ne pokazuju dobru podudarnost. Mogući razlozi navedenih odstupanja mogu biti eksperimentalne prirode, ali i u korištenju neodgovarajućeg analitičkog izraza u slučaju kada se radi o otopinama koje su po svojoj prirodi jaki elektroliti. Glavni uzroci eksperimentalnih pogrešaka mogu biti: nedovoljna izmiješanost otopine čija je provodnost određivana, temperaturne varijacije tijekom eksperimenta, pojava zračnih mjehurića u difuzijskoj ćeliji, konduktometrijska mjerenja koja su izvedena samo na jednoj lokaciji u posudi za miješanje, te eventualne pogreške pri pripravi otopina. U daljnjem radu bilo bi korisno svesti navedene eksperimentalne pogreške na najmanju moguću mjeru, te kod teorijskog određivanja koeficijenta difuzije primijeniti neki drugi izraz koji detaljnije uzima u obzir prirodu analizirane otopine.Mass transfer is an integral part of numerous processes in chemical engineering. Depending on the hydrodynamic conditions within the system, that transfer can occur through molecular diffusion or convection mechanism. In this thesis, mass transfer rate was analysed, focusing exclusively on molecular diffusion mechanism. The effect of concentration of sodium chloride solution on the diffusion coefficient was examined. Diffusion coefficients, whose numerical values give a direct insight in the mass transfer rate, in this work were determined experimentally and using Wilke-Chang’s equation. The results of the experimental measurements, as opposed to the theoretical values obtained, indicate that, with increasing NaCl solution concentration, the value of the diffusion coefficient increases as well. Experimentally and theoretically determined numerical values of the diffusion coefficient do not display an adequate congruence. The possible reasons for said deviation can be of experimental nature, but also caused by the utilization of an unsuitable equation, in the case of solutions which are strong electrolytes. The main causes of experimental errors could be: inadequate mixing of the solution whose electrical conductivity is being measured, variation in temperature during the experiment, the occurrence of air bubbles within the diffusion cell, conductometric measurements which were taken in only one position in the mixing vessel and eventual mistakes during the preparation of the solutions. In future work, it would be useful to minimize the effect of the said experimental mistakes, and to utilize a more suitable equation for the calculation of the theoretical diffusion coefficient, which takes into consideration the nature of the analysed solution in a more strict manner
RECYCLING OF DUROMERS AND ELASTOMERS : bachelor thesis
No full textDuromeri su sintetski polimerni materijali koji nastaju tako da se polimerizat u obliku viskozne kapljevine (smole) umreži i oblikuju u kalupima. Širokog su raspona primjene zbog svojih dobrih fizikalnih, kemijskih i mehaničkih svojstava. Elastomeri su niskoumreženi polimerni materijali na bazi prirodnog ili sintetskog kaučuka i drugih polimera. Procesom vulkanizacije ili drugim načinom umreživanja polimerne molekule kaučuka se poprečno povezuju stvarajući elastomere, tj. gumu. Raširenom upotrebom duromernih i elastomernih materijala nastaju velike količine otpada kojeg je potrebno na adekvatan način zbrinuti. Odlaganjem polimernog otpada bez prethodne oporabe i iskorištavanja vrijednih svojstava, gomilaju se na odlagalištima otpada i ne koriste se u svrhu očuvanja resursa. Postoje tri načina oporabe polimernog materijala, a to su: mehanička, kemijska i energijska oporaba. Odabir određene metode oporabe ovisiti će o strukturi pojedinog polimera.Thermosets are synthetic polymeric materials, which appear in the form of liquids or syrups(resins) and are polymerized and formed into molds. They have a wide range of applications due to their good physical, chemical and mechanical properties. Elastomers are polymeric materials of low crosslinking degree based on natural or synthetic rubber and similar polymers. In the process of vulcanization or another type of crosslinking polymer molecules are linked together to form elastomers, i.e. rubber. The widespread use of thermosets and elastomeric materials produces large amounts of waste that need to be adequately disposed of. Disposing of polymer waste without prior recovery and exploitation of valuable properties, waste dumps are piled up and not used for resource conservation. There are three ways to recover a polymer material: mechanical, chemical and energy recovery. The choice of a particular recovery method will depend on the structure of the individual polymer
Effect of grinding time on the milling efficiency of sodium chloride in a ball mill : bachelor thesis
No full textU ovom radu sagledan je utjecaj vremena mljevenja na proces usitnjavanja natrijevog klorida namijenjenog za komercijalnu uporabu u kugličnom mlinu. Mljevenje je provedeno s dvije različite početne veličinske frakcije natrijevog klorida (x sr = 650 µm i x sr = 2500 µm) i to u vremenskim intervalima od 3 minute, a u sveukupnom trajanju procesa od 15 minuta. Po završetku svakog ciklusa mljevenja izvršena je granulometrijska analiza usitnjenog produkta metodom prosijavanja. Iz rezultata provedenih granulometrijskih analiza uočena je izrazita multimodalnost dobivenih funkcija gustoća raspodjele. Ta multimodalnost se ne mijenja s vremenom mljevenja, ali primjetno je izrazito smanjenje udjela većih frakcija čestica tretiranog partikulskog sustava, odnosno porast udjela onih finijih. Vrijednosti stupnja usitnjavanja značajno se povećavaju s vremenom mljevenja. To se potom odražava na smanjenje vrijednosti srednjeg masenog promjera analiziranog materijala, odnosno na povećanje širine raspodjele, kao i njegove specifične površine.In this thesis the influence of grinding time on the process of size reduction of sodium chloride for commercial use in a ball mill has been examined. Grinding was conducted with two fractions of different initial size of sodium chloride (x sr = 650 µm and x sr = 2500 µm) in time intervals of 3 minutes, for a total process duration of 15 minutes. At the end of each grinding cycle, a granulometric analysis of the milled product was performed using the sieving method. From the results of the granulometric analysis, a noticeable multimodality of the obtained density distribution functions was observed. This multimodality does not change with the grinding time, but a significant decrease of larger particle fractions in the treated particle system, i.e. an increase of the finer ones, is noticeable. The values of the degree of size reduction increase significantly with the grinding time. This is then reflected in the decrease in the value of the mean mass diameter of the analyzed material, i.e. in the increase in the span of particle size, as well as its specific surface area
APPLICATION OF REFRACTOMETRY FOR DETERMINING THE CONCENTRATION OF POTASSIUM SULFATE DURING BATCH CRYSTALLIZATION PROCESS : bachelor thesis
No full textU ovom radu izvršeno je baždarenje refraktometra za potrebe određivanja koncentracije kalijevog sulfata tijekom procesa šaržne kristalizacije. Refraktometrijska metoda ne prikazuje izravno koncentraciju otopine te je potrebno izraditi baždarne krivulje koje predstavljaju odnos indeksa loma i koncentracije tvari pri konstantnim temperaturama. Iz baždarnih krivulja je određena osjetljivost refraktometra. Pripremljenim otopinama kalijevog sulfata poznatih koncentracija mjerio se indeks loma u rasponu temperatura od 15 °C do 35 °C kako bi se procijenio utjecaj grijanja, odnosno hlađenja. Primjenom višestruke linearne regresije određen je kalibracijski model/jednadžba za određivanje koncentracije kalijevog sulfata u procesu šaržne kristalizacije. Šaržna kristalizacija otopine kalijevog sulfata se provodila za otopinu zasićenu na 30 °C, postupkom kontroliranog hlađenja, do temperature od 15 °C. Iako je točnost kalibracijske jednadžbe visoka, rezultati su pokazali da je metoda podložna subjektivnosti mjeritelja kada se koristi analogni refraktometar. Međutim, visoka osjetljivost ukazuje na to da se refraktometrijska metoda može koristiti za relativno precizno određivanje početka nukleacije.In this work, the refractometer was calibrated for the purpose of determining the concentration of potassium sulfate during the batch crystallization process. The refractometric method does not directly show the concentration of the solution, and it is necessary to create calibration curves that represent the relationship between the refractive index and the concentration of the analyte at constant temperatures. The sensitivity of the refractometer was determined from the calibration curves. With prepared potassium sulfate solutions of known concentrations, the refractive index was measured in the temperature range from 15 °C to 35 °C to assess the influence of heating and cooling. Calibration model/equation for determining the concentration of potassium sulfate in the process of batch crystallization was determined by applying multiple linear regression. Batch crystallization of the potassium sulfate solution was carried out for a solution saturated at 30 °C, with a controlled cooling process, to a temperature of 15 °C. Although the accuracy of the calibration equation is high, the results showed that the method is prone to the subjectivity of the measurer when using an analog refractometer. However, the high sensitivity indicates that the refractometric method can be used for relatively accurate determination of the onset of nucleation
Effect of NaX zeolite mass concentration and baffle presence on copper sorption : diploma thesis
No full textSorpcija bakra na NaX zeolitu provedena je u šaržnom reaktoru opremljenom turbinskim miješalom s nagnutim lopaticama (PBT) s i bez razbijala virova. Omjer promjera miješala i reaktora (D/d T =0,32) i pozicija miješala (C/H=0,33) održavani su konstantnima. Brzina vrtnje miješala bila je jednaka najnižoj brzini vrtnje miješala potrebnoj za postizanje stanja potpune suspenzije, tj. kritičnoj brzini vrtnje miješala (N JS ) koja je određena prema Zwieteringovom kriteriju „1 s“ za tri različite masene koncentracije zeolita u oba šaržna reaktora. Uz kinetičke sorpcijske eksperimente i kinetičku analizu dobivenih podataka, kako bi se dobio uvid u hidrodinamičko ponašanje sustava simulirana je dinamika fluida. Brzina N JS povezana je s brzinom taloženja čestica i mijenja se ovisno o masenoj koncentraciji suspenzije. Pri višoj masenoj koncentraciji suspenzije, treba se primijeniti veća N JS brzina kako bi se osiguralo stanje potpune suspenzije, tj. mora se primijeniti više energije (P JS ). Razlike u brzinama N JS za ispitivane masene koncentracije suspenzije nisu značajne pa iz tog razloga povećanje intenziteta miješanja za testirane sustave nije značajno. Iz rezultata se može zaključiti da korišteni hidrodinamički uvjeti ne utječu značajno na maksimalnu količinu sorbiranog bakra, ali na nju značajno utječe masena koncentracija zeolita. Rezultati su pokazali i da je reakcija općenito brža u reaktoru bez razbijala virova te da su vrijednosti N JS i P JS veće u reaktoru bez razbijala virova neovisno o masenoj koncentraciji zeolita.Copper sorption on NaX zeolite using a pitched blade turbine (PBT) was carried out in a baffled and unbaffled batch reactor. The impeller to reactor diameter ratio (D/d T =0.32) and the impeller off-bottom clearance (C/H=0.33) were kept constant. Impeller speed was equal to the lowest impeller speed for complete off-bottom suspension i.e. just suspended impeller speed (N JS ) which was determined according to Zwietering 1s criterion for three different zeolite masses in both batch reactors. Besides kinetic sorption experiments and kinetic analyses of gained data, to get insight into the hydrodynamic behaviour of the system, transient multiphase computational fluid dynamics simulations were performed. The N JS speed is related to the particle settling speed, and for that reason it changes depending on the zeolite suspension mass concentration. At higher zeolite suspension mass concentration, a higher N JS speed must be applied to ensure a complete suspension state, i.e. more energy must be applied. The differences in N JS speeds for the zeolite suspension mass concentrations investigated are not substantial, and for this reason, the increase in mixing intensity for the tested systems is not significant. From the results can be concluded that the hydrodynamic conditions used do not significantly affect the maximum amount of copper sorbed, but it is significantly affected by zeolite mass. The results also showed that the reaction is generally faster in the unbaffled reactor, and that the values of N JS and P JS were higher in an unbaffled reactor regardless of the zeolite mass used