Aromas of decaying Lambic beer : diploma thesis

Pivo je jedno od najstarijih i najpopularnijih pića na svijetu. Proces proizvodnje je složen, ali se tijekom povijesti nije značajno mijenjao. S obzirom na proizvodnju, piva se mogu podijeliti na ona koja se proizvode u velikim količinama, a nazivaju se komercijalna ili lager piva, te na craft piva koja se proizvode po tradicionalnim recepturama i u manjim količinama. Procesom spontane fermentacije nastaje i jedinstveno belgijsko lambic pivo karakteristične voćne arome. Bez obzira na način proizvodnje, pivo predstavlja složenu mješavinu sastojaka koja nastaje kuhanjem vode, hmelja i slada, te fermentacijom pripravljene sladovine posredstvom kvasaca. Sadrži visok raspon kemijskih spojeva koji nastaju u svim fazama proizvodnje, a brojni spojevi piva imaju važnu ulogu u formiranju njegova okusa. U ovom su radu identificirani i analizirani spojevi arome iz triju uzoraka lambic piva korištenjem dviju metoda izolacije: mikroekstrakcija vršnih para na krutoj fazi i ekstrakcija tekuće-tekuće. Dobiveni rezultati pokazali su veliku raznolikost identificiranih aromatskih spojeva. Vidljive su određene sličnosti u izoliranim spojevima između uzoraka – najzastupljenije skupine izoliranih spojeva pripadaju alkoholima, kiselinama, aldehidima, ketonima, esterima i fenolima, a 2-feniletanol pojavljuje se u svim ispitivanim uzorcima.Beer is one of the oldest and most popular beverages in the world. The production process is complex, but has not significantly changed throughout history. In terms of production, beers can be divided into those produced in large quantities, known as commercial or lager beers, and craft beers produced according to traditional recipes and in smaller quantities. The process of spontaneous fermentation creates a unique Belgian lambic beer with a characteristic fruity aroma. Regardless of the production method, beer represents a complex mixture of ingredients that is created by boiling water, hops and malt, and by fermenting the prepared wort with the help of yeasts. It contains a wide range of chemical compounds that are formed in all stages of production, and numerous beer compounds play an important role in the formation of its taste. In this study, aromatic compounds from three samples of lambic beer were identified and analyzed using two isolation methods: solid- phase microextraction and liquid-liquid extraction. The results showed a great diversity of identified aromatic compounds. Certain similarities in the isolated compounds between samples are evident – the most prevalent groups of isolated compounds belong to alcohols, acids, aldehydes, ketones, esters, and phenols, with 2- phenylethanol appearing in all tested samples

Methods for obtaining minerals from sea bittern : bachelor thesis

Završni rad predstavlja literaturni pregled metoda dobivanja minerala iz gorke morske vode. Gorka morska voda nastaje kao nusproizvod pri proizvodnji morske soli te predstavlja koncentrirani oblik mnogih soli. Elementi koji sačinjavaju gorku morsku vodu su: Na, Mg, Ca, K, Li, Rb, Pb, U, Zn, a primjenom inovativnih metoda mogu se dobiti iz gorke morske vode. Metode koje se danas primjenjuju su nanofiltracija, elektrodijaliza, elektroliza, precipitacija, ekstrakcija uz primjenu otapala, ionska izmjena, toplinski procesi i kombinirani procesi. Usavršavanjem metoda omogućava se potpuno ili djelomično zbrinjavanje gorke morske vode te se smanjuje štetni utjecaj na okoliš kao i dobivanje minerala visoke čistoće. Glavni cilj je povećanje učinkovitosti, poboljšanje eksploatacije minerala i što veće iskorištenje gorke morske vode.The bachelor thesis presents a literature review of methods for obtaining minerals from sea bittern. Sea bittern is formed as a by-product in the production of sea salt and is a concentrated form of many minerals. Sea bittern contains elements such as: Na, Mg, Ca, K, Li, Rb, Pb, U, Zn, which by applying innovative methods can be exploited. The methods used today are nanofiltration, electrodialysis, electrolysis, precipitation, solvent extraction, ion exchange, thermal processes and combined processes. The improvement of methods enables complete or partial disposal of sea bittern, the reduction of negative environmental impacts as well as the production of minerals of high purity. The main goal is to increase efficiency, improve mineral exploitation and maximize the use of sea bittern

Influence of current density and zeolite particle size on the hybrid process of leachate treatment by electrocoagulation in the presence of zeolite : bachelor thesis

Iako korozija konstrukcijskih materijala predstavlja negativnu pojavu, kada se elektrokemijski postupci koriste za pročišćavanje otpadnih voda, anodno otapanje metala može imati pozitivan učinak. U ovom radu, ispitan je utjecaj različitih gustoća struje nakon primjene u obradi otpadne vode hibridnim procesom elektrokoagulacije i sintetskog zeolita. Ispitan je i utjecaj različitih veličina čestica zeolita na otapanje elektrode, stanje površine elektrode i efikasnost uklanjanja. Površina elektroda analizirana je snimanjem sa svjetlosnim mikroskopom uz različita uvećanja. Ispitan je utrošak aluminijevih elektroda tijekom hibridnog procesa elektrokoagulacije u prisustvu sintetskog zeolita, te su izvedeni zaključci o stanju površine elektroda nakon odvijanja hibridnog procesa. Bolja efikasnost uklanjanja dobivena je provođenjem eksperimenta pri većim gustoćama struje kao i kod sustava koji su se provodili uz dodatak zeolita veće veličine čestica. Značajno veća oštećenja su na elektrodama koje su se koristile u eksperimentu s dvostruko većom gustoćom struje. Također, značajna oštećenja su zamijećena na elektrodi koja su se koristila u eksperimentu s većim česticama zeolita, što se može povezati s njihovim izraženijim abrazivnim djelovanjem.Although the corrosion of structural materials is a negative phenomenon, when electrochemical processes are used for wastewater treatment, anodic dissolution of metals can have a positive effect. In this work, the influence of different current densities was investigated after they were used in wastewater treatment by a hybrid process of electrocoagulation combined with the addition of synthetic zeolite. Also, the influence of different zeolite particle size on electrode dissolution, electrode surface condition and removal efficiency were tested. The surface of the electrodes was analyzed by recording it with a light microscope at different magnifications. The consumption of aluminum electrodes during the hybrid process of electrocoagulation in the presence of synthetic zeolite was examined, and conclusions were drawn about the condition of the surface of the electrodes after the hybrid process. Better removal efficiency was obtained by conducting the experiment at higher current densities and in systems using larger zeolites particles. The electrodes used in the experiment with double current density were significantly more damaged. Significant damage was also observed on the electrode used in the experiment with larger zeolite particles, which can be associated with the stronger abrasive effect

Impact of SBT impeller speed on copper sorption on zeolite : diploma thesis

U ovom radu ispitivan je utjecaj brzine vrtnje turbinskog miješala s ravnim lopaticama tzv. SBT miješalo na sorpciju bakra na zeolitu NaX i utrošak snage miješanja pri konstantnoj temperaturi. Eksperiment je proveden u kotlastom reaktoru s razbijalima virova pri četiri različite brzine vrtnje miješala. Korištenjem Ritchievog modela i Weber-Morrisovog modela izvršena je kinetička analiza dobivenih kinetičkih eksperimentalnih podataka. Vrlo dobro slaganje dobivenih podataka s Ritchijevim modelom ukazuje na to da ispitivana reakcija prati kinetiku drugoga reda i da povećanjem brzine vrtnje SBT raste utrošak snage miješanja.The influence of the mixing speed of a turbine impeller with straight blades (SBT) of copper sorption on NaX zeolite and power consumption at constant temperature were investigated. The experiment was conducted in a batch reactor with baffles at four different impeller speeds. A kinetic analysis of the obtained kinetic experimental data was performed by the Ritchie model and the Weber-Morris model. Good agreement of the obtained data with Ritchie's model indicates that the reaction investigated follows the second-order kinetics and that the power consumption increases with increasing SBT speed

Xanthine oxidase and from nature isolated inhibitors of this enzyme : bachelor thesis

: Cilj ovog završnog rada bio je pregled dostupne znanstvene literature na temu inhibicije enzima ksantin-oksidaze prirodnim spojevima izoliranim iz biljaka. Ksantin-oksidaza je enzim koji ima važnu ulogu u metabolizmu purinskih baza i samim tim u patogenezi gihta. Obzirom da lijekovi koji se koriste u liječenju ove bolesti sadrže i stanovite nuspojave neprestalno se traže iz prirode izolirani inhibitori ovog enzima s ciljem moguće prevencije i / ili tretmana gihta. Kao izvori podataka koristile su se dostupne relevantne znanstvene baze podataka Web of Science Core Collection i Scopus. Pregledom literature utvrđen je veliki broj objavljenih radova na temu inhibicije enzima ksantin oksidaze ekstraktima i spojevima koji ulaze u sastav ekstrakata biljaka. Rezultati su pokazali da su flavonoidi izolirani iz biljnih ekstrakata izvrstan izvor spojeva s inhibicijskim potencijalom na enzim ksantin-oksidazu.The aim of this study was to review available scientific literature on the inhibition of xanthine oxidase enzymes by natural compounds isolated from plants. Xanthine oxidase is an enzyme that plays an important role in the metabolism of purine bases and hence in the pathogenesis of gout. Since medicines used to treat this disease also contain certain side effects, isolated inhibitors of this enzyme are continuously sought from nature with the aim of possible prevention and/or treatment of gout. The relevant scientific databases Web of Science Core collection and Scopus were used as data sources. The literature review revealed that a large number of papers on the inhibition of xanthine oxidase enzymes by extracts and compounds forming part of plant extracts have been published to date. The results showed that flavonoids isolated from plant extracts are an excellent source of compounds with inhibitory potential on xanthine oxidase enzyme

Srtuctural diverity of glucosinolates and their breakdown products in different plant familes : docotral thesis

SAŽETAK Raspodjela glukozinolata unutar biljnih porodica reda Brassicales istražena je UHPLC- DAD-MS/MS analizom desulfoglukozinolata na temelju određenih kvalitativnih i kvantitativnih informacija i to u različitim biljnim tkivima četrdeset osam (48) biljaka iz pet (5) biljnih porodica (Brassicaceae, Capparidaceae, Moringaceae, Resedaceae, Tropaeolaceae) koje rastu u Republici Hrvatskoj i šire. Razvijena je baza MS2 spektara desulfoglukozinolata korištenjem komercijalno dostupnih standarda kao i glukozinolata izoliranih iz prirodnih izvora. Biljna porodica Brassicaceae je sadržavala najraznolikije glukozinolate koje potječu od sedam (7) aminokiselinskih prekursora, i to najčešće od metionina, praćeno s glukozinolatima koji potječu od triptopfana te fenilalanina i/ili tirozina, dok su razgranati alifatski glukozinolati koji potječu od valina, leucina i izoleucina zastupljeni tek u rijetkim vrstama. Jedini poznati glukozinolat, glukokaparin, koji potječe od aminokiseline alanina identificiran je samo u porodici Capparidaceae i to kao glavni u svim istraženim vrstama, dok su ostali glukozinolati u većoj mjeri potjecali od triptofana. Moringa oleifera (porodica Moringaceae) sadržavala je 4-(α-L- ramnopiranoziloksi)benzil-glukozinolat te u manjim količinama tri (3) O-acetilirana izomera istog glukozinolata čiji aminokiselinski prekursor je fenilalanin i/ili tirozin. U vrstama Reseda lutea i R. phyteuma (porodica Resedaceae) identificiran je izomer 4-(α-L-ramnopiranoziloksi)benzil-glukozinolata, 2-(α-L-ramnopiranoziloksi)benzil- glukozinolat karakterističan za biljnu porodicu Resedaceae, koji potječe od fenilalanina, dok je u R. alba kao glavni glukozinolat identificiran 2-hidroksi-2-metilpropil- glukozinolat koji potječe od izoleucina. Tropaeolum majus je sadržavao arilalifatski benzil-glukozinolat kao glavni, praćen sa 3-metoksibenzil-glukozinolatom, a oba potječu od fenilalanina, jedinog poznatog aminokiselinskog prekursora glukozinolata u porodici Tropaeolaceae. Uvidom u kvantitativni sastav glukozinolata odabrane su biljne vrste kao dobri izvori glukozinolata koji su izolirani u obliku desulfoglukozinolata i potvrđeni spektroskopskim tehnikama (MS2, 1 H, 13 C, COSY i HSQC NMR). 3-(Metilsulfinil)propil-glukozinolat je izoliran iz biljke Anastatica hierochuntica (porodica Brassicaceae), 4-hidroksibenzil-glukozinolat iz vrste Sinapis alba (porodica Brassicaceae), metil-glukozinolat iz Capparis orientalis (porodica Capparidaceae), 2-hidroksi-2-metilpropil-glukozinolat iz biljke Reseda alba (porodica Resedaceae) te benzil-glukozinolat iz Tropaeolum majus (porodica Tropaeolaceae). Također, na temelju MS2 spektara i biosintetskih karakteristika identificirana su 4 nova glukozinolata: orto ili meta hidroksi-4-(α-L-ramnopiranoziloksi)benzil-glukozinolat (Moringa oleifera), 4´-O- (β-D-apiofuranoziloksi)benzil-glukozinolat (Hesperis laciniata i Thlaspi perfoliatum), 4- hidroksi-1-metoksiindol-3-ilmetil-glukozinolat (Thlaspi perfoliatum) te 3-hidroksi-(4- metilsulfonil)butil-glukozinolat (Barbarea vulgaris) čije strukture trebaju dodatnu potvrdu NMR-om. Stabilnost desulfo-4-(metilsulfinil)but-3-enil-glukozinolata izoliranog iz biljke Matthiola incana ispitivana je tijekom jednomjesečnog razdoblja te je utvrđena njegova nestabilnost u vodenoj otopini, odnosno drastičan pad sadržaja (do 80 %) praćen spontanom konverzijom u cikličke tioimidatne N-okside. Korištenjem konvencionalnih (enzimska hidroliza i hidrodestilacija) te modernih metoda (mikrovalna destilacija te hidrodifuzija i gravitacija) ispitan je enzimski i termički utjecaj na razgradnju glukozinolata. U uvjetima termičke razgradnje potpomognute mikrovalovima dobiveni su manji prinosi razgradnih produkata u odnosu na termičku razgradnju tijekom hidrodestilacije te enzimsku hidrolizu. Izotiocijanati kao razgradni produkti glukozinolata su se pokazali nestabilnim pri uvjetima GC-MS mjerenja i to za ω-metilsulfinilne C3, C5 i C6 izotiocijanate čiji je raspad rezultirao nastankom odgovarajućih olefinskih izotiocijanata. Dodatno, zbog prisutnosti elektron-donirajuće hidroksilne skupine u para položaju na benzenskom prstenu, kod 4-hidroksibenzil- izotiocijanata i 4-hidroksi-3,5-dimetoksibenzil-izotiocijanata, utvrđena je nestabilnost koja vodi ka nastanku artefakata tijekom GC-MS mjerenja. Također, razgradni produkti indolnih glukozinolata nisu identificirani. Ovime je istaknut nedostatak neizravne metode identifikacije glukozinolata preko razgradnih produkata u biljnim vrstama. U biljci Eruca vesicaria biofortificiranoj selenijem iz natrijevog selenata identificiran je 4-(metilseleno)butil-glukozinolat izveden iz selenometionina na temelju MS2 spektra koji je po prvi puta prikazan. Utvrđeno je da hidroponski uzgojene klice pet (5) odabranih biljaka iz porodice Brassicaceae imaju visoki sadržaj karakterističnih glukozinolata zbog čega predstavljaju dobar izvor za njihovu izolaciju.ABSTRACT Distribution of glucosinolates within plant families of the order Brassicales was investigated using qualitative and quantitative UHPLC-DAD-MS/MS analysis of desulfoglucosinolates in different plant tissues of forty-eight (48) plants from five (5) plant families (Brassicaceae, Capparidaceceae, Moringaceae, Resedaceae, Tropaeolaceae) growing in the Republic of Croatia and worldwide. A database of MS2 spectra of desulfoglucosinolates was developed using commercially available standards as well as glucosinolates isolated from natural sources. The Brassicaceae plant family contained a wide variety of glucosinolates derived from seven (7) different amino acid precursors, most commonly from methionine, followed by glucosinolates derived from tryptophan, phenylalanine and/or tyrosine, while branched aliphatic glucosinolates deriving from valine, leucine and isoleucine were scarce. Glucocapparin, the only known glucosinolate derived from the amino acid alanine, was identified solely in the Capparidaceae family as the main one in all the species studied, while the other glucosinolates largely derived from tryptophan. Moringa oleifera (family Moringaceae) contained 4-(α-L-rhamnopyranosyloxy)benzyl glucosinolate and, in less amount, three O-acetylated isomers of the same glucosinolate derived from phenylalanine and/or tyrosine. In the species Reseda lutea and R. phyteuma (family Resedaceae) an isomer of 4-(α-L-rhamnopyranosyloxy)benzyl glucosinolate, 2- (α-L-rhamnopyranosyloxy)benzyl glucosinolate, was identified characteristic for the plant family Resedaceae, originating from phenylalanine. On the other hand, 2-hydroxy- 2-methylpropyl glucosinolate derived from isoleucine was the major glucosinolate identified in R. alba. The main glucosinolate in Tropaeolum majus was arylaliphatic benzyl glucosinolate followed by 3-methoxybenzyl glucosinolate, both derived from phenylalanine, the only known amino acid precursor of glucosinolates in the Tropaeolaceae family. Insight into the quantitative composition of glucosinolates enabled the selection of the plant species as the sources of glucosinolates for their isolation in the form of desulfoglucosinolates and confirmation by spectroscopic techniques (MS2, 1 H, 13 C, COSY and HSQC NMR). 3-(Methylsulfinyl)propyl glucosinolate was isolated from Anastatica hierochuntica (family Brassicaceae), 4-hydroxybenzyl glucosinolate from Sinapis alba (family Brassicaceae), methyl glucosinolate from Capparis orientalis (family Capparidaceae), 2-hydroxy-2-methylpropyl glucosinolate from Reseda alba (family Resedaceae) and benzyl glucosinolate from Tropaeolum majus (family Tropaeolaceae). Also, based on MS2 spectra and biosynthetic characteristics, four (4) new glucosinolates were identified: ortho or meta hydroxy-4-(α-L- rhamnopyranosyloxy)benzyl glucosinolate (Moringa oleifera), 4´-O-(β-D- apiofuranosyloxy)benzyl glucosinolate (Hesperis laciniata and Thlaspi perfoliatum), 4- hydroxy-1-methoxyindol-3-ylmethyl glucosinolate (Thlaspi perfoliatum) and 3-hydroxy- (4-methylsulfonyl)butyl glucosinolate (Barbarea vulgaris) whose structures need further confirmation by NMR. The stability of desulfo-4-(methylsulfinyl)but-3-enyl glucosinolate isolated from Matthiola incana was studied over a one-month period and its instability in aqueous solution was observed, showing a significant drop in the content (up to 80%) followed by spontaneous conversion to cyclic thioimidate N-oxides. The enzymatic and thermal degradation of glucosinolates was studied by using conventional (enzymatic hydrolysis and hydrodistillation) and modern methods (microwave distillation and hydrodiffusion and gravity). Under microwave-assisted thermal decomposition conditions, lower yields of decomposition products were obtained compared to thermal decomposition during hydrodistillation and enzymatic hydrolysis. Isothiocyanates as degradation products of glucosinolates showed to be unstable at GC-MS conditions for ω-methylsulfinyl C3, C5 and C6 isothiocyanates, which decomposition resulted in the formation of the corresponding olefinic isothiocyanates. Additionally, due to the presence of an electron- donating hydroxyl group in the para position on the benzene ring, in 4-hydroxybenzyl isothiocyanate and 4-hydroxy-3,5-dimethoxybenzyl isothiocyanate, instability lead to formation of artifacts found during GC-MS analysis. Also, degradation products of indole glucosinolates have not been identified. This highlights the disadvantage of an indirect method for the identification of glucosinolates via their degradation products in plant species. In the Eruca vesicaria biofortified by selenium from sodium selenate, 4- (methylseleno)butyl glucosinolate derived from selenomethionine was identified based on the MS2 spectrum shown for the first time. Hydroponically grown sprouts of the five (5) selected plants of Brassicaceae family were found to have a high content of characteristic glucosinolates presenting a good source for their isolation

Copper ions sorption on milled peanut shells : bachelor thesis

U ovom radu ispitivala se ravnoteža sorpcije bakrovih iona na osušenoj i usitnjenoj ljusci kikirikija na klasu čestica promjera između 100 i 200 µm. Eksperimenti su se provodili u pet šaržnih reaktora, u suspenzijama od po 1 g usitnjene ljuske kikirikija te 0,2 L otopine bakrovog(II) klorida dihidrata različitih početnih koncentracija. Pripremljene suspenzije miješane su u vodenoj kupelji s trešnjom pri izotermnim uvjetima (T = 27 °C) i brzini od 200 okr/min. Uzorci suspenzija su uzorkovani i analizirani UV/VIS spektrofotometrom u definiranim vremenskim intervalima tijekom 96 sati kako bi se u ispitivanom sustavu utvrdilo uspostavljanje ravnotežnog stanja. Dobiveni eksperimentalni podatci analizirani su Langmuirovom, Freundlichovom i Sipsovom izotermom. Analiza slaganja eksperimentalnih podataka s adsorpcijskim izotermama te vrijednosti izračunatog RMSE parametra pokazali su kako se Langmuirova izoterma najbolje slaže s eksperimentalnim podatcima te da se učinkovitost sorpcije smanjuje porastom početne koncentracije otopine bakrovog(II) klorida dihidrata. U svim ispitivanim sustavima ravnotežno stanje je postignuto nakon 24 sata; količina bakrovih iona vezanih u ravnoteži neovisna je o početnim koncentracijama otopina i iznosi oko 0,20 mmol/g, osim za najnižu korištenu koncentraciju.In this thesis, the equilibrium of copper ion sorption on dried and milled peanut shell particles with diameter between 100 and 200 µm was investigated. The experiments were carried out in five batch reactors, in suspensions of 1 g of milled peanut shells and 0.2 L of copper(II) chloride dihydrate solution of different initial concentrations. The prepared suspensions were mixed under isothermal conditions (T = 27 °C) and at a speed of 200 rpm. Suspension samples were sampled and analyzed with a UV/VIS spectrophotometer at defined time intervals during 96 hours to verify if an equilibrium state had been established in the systems investigated. The obtained experimental data were analyzed by Langmuir, Freundlich and Sips isotherms. The analysis of the agreement of the experimental data with the adsorption isotherms and the values of the calculated RMSE parameter revealed that the Langmuir isotherm shows the best agreement with the experimental data and that the sorption efficiency decreases with the initial concentration of the copper(II) chloride dihydrate increase. In all systems tested, equilibrium state was reached after 24 hours; the amount of copper ions retained on milled peanut shells in equilibrium is independent of the initial concentrations of the solutions and is about 0.20 mmol/g, except for the lowest concentration used

Aplication of the hybrid process of electrocoagulation and natural zeolite for treatment of compost leachate : bachelor thesis

U ovom radu provedena su ispitivanja hibridnog procesa elektrokoagulacije i prirodnog zeolita za obradu kompostne procjedne vode. Ispitivan je utjecaj početne koncentracije kompostne procjedne vode na efikasnost uklanjanja štetnih tvari praćenih preko kemijske potrošnje kisika (KPK) i mutnoće. Eksperimenti su provedeni u elektrokemijskoj ćeliji, uz korištenje aluminijevih elektroda, pri konstantnoj udaljenosti elektroda od 3 cm i brzine vrtnje miješala od 70 okr/min. Tijekom eksperimenta praćena je promjena pH vrijednosti, temperature i električne vodljivosti, a na početku i kraju eksperimenta određivani su mutnoća, ukupni isparni ostatak, kemijska potrošnja kisika. Nakon provedenog eksperimenta hibridnog procesa elektrokoagulacije s prirodnim zeolitom ispitan je test taloživosti. Rezultati pokazuju da je kod veće početne koncentracije KPK u početnoj kompostnoj procjednoj vodi veća količina uklonjene štetne tvari te se postiže veća brzina taloženja. Ispitani su utrošci aluminijevih elektroda tijekom hibridnog procesa elektrokoagulacije i prirodnog zeolita te su izračunati operativni troškovi.In this paper, the integrated process of electrocoagulation and natural zeolite was applied for compost leachate treatment. The influence of the initial chemical oxygen demand (COD) concentration of compost leachate on the removal efficiency of harmful substances monitored through COD and turbidity was investigated. The experiments were performed in an electrochemical cell, using aluminum electrodes, at a constant electrode distance of 3 cm and at stirring speed of 70 rpm. During the experiment, the change in pH, temperature and electrical conductivity was measured, and at the beginning and end of the experiment, turbidity, total solids, and COD were determined. After conducting an experiment of integrated electrocoagulation with natural zeolite, a settling test was examined. The results show that higher initial concentration of COD in the compost leachate induce higher amount of removed harmful substances and higher settling rate. The consumption of aluminum electrodes during the hybrid process of electrocoagulation and natural zeolite was analyzed, and operation costs were calculated

Determination of residual copper content in soil after the phytoremediation process with the rocket and the garden candytuft : diploma thesis

Globalni napredak stvorio je mnoge probleme u zaštiti i očuvanju okoliša. Kontaminacija tla otrovnim tvarima se povećala i postala globalni problem. Mnogi od zagađivača su kancerogeni i mutageni te predstavljaju ozbiljan problem za ljudsko zdravlje. Zagađenje tla teškim metalima predstavlja jednu od najvećih briga današnjice. Neke vrste teških metala su otrovne i smrtonosne, čak i u malim koncentracijama, dok druge mogu uzrokovati neurološke poremećaje te druga teška oboljenja. Stoga je sanacija tla zagađenih teškim metalima vrlo važna i u današnje vrijeme naglasak se stavlja na fitoremedijaciju kao ekonomičnu i ekološki prihvatljivu metodu. U ovom diplomskom radu određivana je koncentracija zaostalog bakra, kao teškog metala, u humusu u kojemu su rasle dvije biljke; rukola i štitasta ognjica. Obje biljke su služile kao hiperakumulatori bakra. Određen je sadržaj bakra u šest različito pripremljenih humusa (ukupno 12 za obje biljke): čisti humus bez dodataka, humus s dodatkom letećeg pepela na koji je adsorbiran bakar, humus u koji je dodan humus na koji je adsorbiran bakar, humus s dodatkom ljuski jaja na koje je adsorbiran bakar, humus s dodatkom zeolita na koji je adsorbiran bakar te posljednji humus u kojem su biljke bile zalijevane samo s vodenom otopinom bakrovog(II) sulfata. Uočava se povišen sadržaj bakra u svim uzorcima humusa osim u kontrolnim uzorcima. Na temelju izmjerenog sadržaja bakra može se zaključiti kako su biljke ipak, u većoj ili manjoj mjeri, usvojile bakar iz humusa u koji su dodani adsorbensi na koje je prethodno vezan bakar kao teški metal, kao i one koje su zalijevane isključivo vodenom otopinom bakrovog(II) sulfata.Global progress has created many problems in protecting and preserving the environment. Soil contamination with toxic substances has increased and become a global problem. Many of the pollutants are carcinogenic and mutagenic and represent a serious problem to human health. Soil pollution with heavy metals is one of the biggest concerns of today. Some types of heavy metals are toxic and deadly, even in small concentrations, while others can cause neurological disorders and other serious illnesses. Therefore, remediation of soils contaminated with heavy metals is very important and nowadays the emphasis is placed on phytoremediation as an economical and environmentally friendly method. In this diploma thesis, the concentration of residual copper, as a heavy metal, in humus in which two plants grew was determined; rocket and garden candytuft. Both plants served as copper hyperaccumulators. Copper content was determined in six differently prepared humus (a total of 12 for both plants): pure humus without additives, humus with the addition of fly ash on which copper was adsorbed, humus with the addition of humus on which copper was adsorbed, humus with the addition of egg shells on which copper was adsorbed, humus with the addition of zeolite on which copper was adsorbed, and the last, humus in which the plants were watered only with an aqueous solution of copper(II) sulphate. Elevated copper content is observed in all humus samples except in control samples. Based on the measured copper content, it can be concluded that the plants still, to a greater or lesser extent, adopted copper from humus to which adsorbents were added to which copper was previously adsorbed as a heavy metal, as well as those watered exclusively with aqueous copper(II ) sulphate

Corosion behaviour of stainless steel in seawater : master thesis

Utjecaj temperature i koncentracije sulfidnih iona na korozijsko ponašanje nehrđajućih čelika 304L i 316L u morskoj vodi istraživan je različitim elektrokemijskim metodama. Tijekom istraživanja korištena su mjerenja potencijala otvorenog kruga, metode linearne i potenciodinamičke polarizacije. Utvrđeno je da se brzina korozije povećava s povećanjem temperature morske vode, a također i koncentracije sulfidnih iona. Analiza površine svjetlosnim mikroskopom i optičkim profilometrom nakon mjerenja potenciodinamičke polarizacije otkrila je da se broj i dubina jamica također povećavaju na isti način.The effect of temperature and concentration of sulphide ions on the corrosion behaviour of 304L and 316L stainless steels in seawater has been investigated by different electrochemical methods. Open circuit potential measurements, linear and potentiodynamic polarization methods have been employed during the investigation. It has been found that the corrosion rate increases with the seawater’s increasing temperature and the concentration of sulphide ions. Surface analysis with a light microscope and optical profilometer after potentiodynamic polarization measurements reveal that the number and depth of pits also increase in the same way