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Analysis of the impact of pH change and zeolite addition on the efficiency of municipal wastewater treatment using the intergrated process of electrocoagulation and natural zeolite : bachelor thesis
No full textKomunalne otpadne vode je potrebno pročistiti prije ispuštanja u prirodni recipijent kako bi se spriječilo onečišćenje. U ovom radu ispitan je integrirani proces elektrokoagulacije i prirodnog zeolita za obradu komunalne otpadne vode. Eksperiment je proveden u elektrokoemijskoj čeliji sa elektrodama od aluminija uz dodatak zeolita te vremenom kontakta od 60 minuta. Analiziran je utjecaj dodatka zeolita i podešavanja početne pH vrijednosti (pH=4, pH=9 i bez podešavanja početne pH vrijednosti) na učinkovitost procesa. Rezultati pokazuju da podešavanje početne pH vrijednosti i dodatak zeolita imaju znatan utjecaj na smanjenje mutnoće, brzine taloženja i ukupnog dušika po Kjeldahlu, dok utjecaj na smanjenje KPK i električne vodljivost nije značajan.Municipal wastewater must be purified before discharge into a natural recipient in order to prevent pollution. In this paper, the integrated process of electrocoagulation and natural zeolite for the treatment of minicipal wastewater was examined. The experiment was conducted in an electrochemical cell with aluminium electrodes with the addition of zeolite and a contact time of 60 minutes. The influence of the addition of zeolite and the adjustment of the initial pH value (pH=4, pH=9 and without pH adjustment) on the efficiency of the process was analyzed. Results show that the adjustment of the initial pH value and addition of zeolite have a significant impact on the reduction of turbidity, deposition rate and total Kjeldahl nitrogen, while the impact on the reduction of COD and electrical conductivity is not significant
Corrosion inhibition of copper by non-toxic natural compounds : diploma thesis
No full textU ovom radu ispitana je mogućnost primjene želatine te smjese želatine i alge Padina pavonica kao netoksičnih zaštitnih prevlaka bakra u 0,5 mol dm –3 otopini NaCl pri različitim temperaturama. Prirodni netoksični spojevi naneseni su na površinu bakra sol-gel postupkom uranjanjem. Istraživanja su provedena elektrokemijskim metodama (metoda mjerenja potencijala otvorenog kruga, metoda linearne polarizacije i potenciodinamička polarizacijska metoda), dok je površina ispitivanog materijala analizirana pomoću optičkog mikroskopa. Analize pokazuju kako prevlaka želatine smanjuje brzinu korozije bakra u ispitivanoj otopini, dok prevlaka želatine i Padina pavonica ima veći antikorozivni učinak od sume njihovih pojedinačnih djelovanja, tj. povećava stupanj inhibicije bakra u otopini kloridnih iona. Navedeno je posebno naglašeno kod prevlake želatine i alge masene koncentracije 0,8 g dm –3 , gdje je postignuta inhibicija korozije preko 90 %. Dobiveni rezultati pokazuju kako je smjesa želatine i Padina pavonica mješoviti inhibitor, a veća zaštita bakra u ispitivanim uvjetima može se objasniti sinergizmom ispitivanih netoksičnih organskih spojeva.The possibility of using gelatine and a mixture of gelatine and alga Padina pavonica as non-toxic protective coatings of copper in 0.5 mol dm –3 NaCl solution at different temperatures was studied in the present work. Natural non-toxic compounds were deposited on the copper surface by the dip-coating method. This study was carried out by electrochemical techniques (open circuit potential measurement, linear polarisation, and potentiodynamic polarisation measurement), while the specimen’s surface was examined using optical microscope. Analyses show that the gelatine coating reduces the corrosion rate of copper in the test solution, while the gelatine and Padina pavonica coating have a greater anticorrosive effect than the sum of their individual actions, ie. increases the degree of inhibition of copper in chloride ion solution. This is especially emphasized in the coating of gelatine and alga with a mass concentration of 0.8 g dm –3 , whereby corrosion inhibition of over 90% is achieved. The results obtained showed that the mixture of gelatine and Padina pavonica is a mixed inhibitor, and the higher protection of copper under the tested conditions can be explained by the synergism of the tested non-toxic organic compounds
Processing of hydrogen-rich off gases in the pressure-swing adsorption unit of the hydrogen production plant : bachelor thesis
No full textAdsorpcija uz promjenu tlaka – PSA (engl. Pressure-swing adsorption) jedna je od najvažnijih operacija za razdvajanje i pročišćavanje plinovitih smjesa. U naftnoj i petrokemijskoj industriji najčešće se koristi za izdvajanje vodika iz plinova bogatih vodikom te za razdvajanje smjese zraka na kisik i dušik. U rafineriji Proizvodnja Rafinerije i marketing lokacija Rijeka, adsorpcijska jedinica 380-PSA2 je izgrađena 2010. godine u sklopu postrojenja za proizvodnju vodika 380-HGU (engl. Hydrogen Generation Unit). Na ovoj se jedinci kontinuirano pročišćava sintezni plin u svrhu dobivanja vodika visoke čistoće koji se potom, u ovoj rafineriji, koristi u sekundarnim (konverzijskim i rafinacijskim) procesima prerade nafte. U svrhu smanjenja potrošnje prirodnog plina, na 380-PSA2 jedinci se osim sinteznog plina pročišćavaju i plinovi bogati vodikom s 376-Hidrokreking postrojenja te 313-Platforming2 postrojenja. U ovom radu, u riječkoj rafineriji, analiziran je rad 380-PSA2 adsorpcijske jedinice kada se na njoj obrađuje sintezni plin, ali i smjesa sinteznog plina i plinova bogatih vodikom s 376-Hidrokreking postrojenja te smjesa sinteznog plina, plinova bogatih vodikom s 376-Hidrokreking postrojenja i plina bogatog vodikom s 313-Platforming2 postrojenja. Analiza rada 380-PSA2 adsorpcijske jedinice temeljila se na sagledavanju protoka i sastava pojnih smjesa i produkata, pri različitim radnim kapacitetima postrojenja. Na temelju rezultata, dan je osvrt na utjecaj faktora kapaciteta 380-PSA2 jedinice na čistoću i količinu proizvedenog vodika. U radu su također procijenjene uštede prirodnog plina i smanjenje emitiranja CO 2 kada se osnovna sirovina, sintezni plin, djelomično zamjenjuje plinovima s 376-Hidrokreking postrojenja te 313- Platforming2 postrojenja. Uzimajući u obzir cijene prirodnog plina te cijene emisijske jedinice CO 2 za promatrano ljetno razdoblje 2024. godine, u radu su procijenjene ukupne uštede pri zadanim uvjetima rada 380-PSA2 jedinice.Pressure-swing adsorption (PSA) is one of the most important processes for separating and purifying gaseous mixtures. In the oil and petrochemical industry, it is most commonly used to purify hydrogen from hydrogen-rich gases and to separate air into oxygen and nitrogen. The 380-PSA2 adsorption plant was built at Production Refineries and marketing location Rijeka refinery in 2010, as part of the 380- HGU (Hydrogen Generation Unit). In this plant, synthesis gas is continuously purified to produce high- purity hydrogen, which is then used in secondary (conversion and refining) oil refining processes. To reduce natural gas consumption, the 380-PSA2 unit purifies hydrogen-rich off gases from the 376-Hydrocracking unit and the 313-Platforming2 unit in addition to syngas. This paper analyses the operation of the 380-PSA2 adsorption unit at the Rijeka refinery when processing syngas and a mixture of syngas and hydrogen-rich off gases from the 376-Hydrocracking unit and a mixture of syngas, hydrogen-rich off gases from the 376-Hydrocracking unit and hydrogen-rich off gas from the 313-Platforming2 unit. The 380-PSA2 adsorption unit was analysed by observing the flow rates and composition of the feed gas mixtures and products at different operating capacities of the unit. The results were used to provide an overview of the impact of the capacity factor of the 380-PSA2 unit on the purity and quantity of hydrogen produced. The study also evaluated the savings in natural gas and reduction in CO 2 emissions when the primary feedstock, syngas, is partially replaced by off gases from the 376-Hydrocracking unit and the 313-Platforming2 unit. Taking into account natural gas prices and the price of CO 2 emission allowances during the observed summer period of 2024, the study estimated the total savings under the specified operating conditions of the 380-PSA2 plant
Qualitative and quantitative determination of ibuprofen and carbendazim using UHPLC-DAD-MS/MS : diploma thesis
No full textOvaj rad pruža teorijski uvid u biološki aktivne tvari ibuprofen i karbendazim, te način njihovog dospijevanja u okoliš. Također, opisani su osnovni principi kromatografskih tehnika s naglaskom na UHPLC-DAD-MS/MS te razvoj instrumentalne metode. Kao otapalo za pripravu standardnih otopina ibuprofena i karbendazima odabran je metanol. Eksperimentalno je odabrana kolona te sastav pokretne faze za tekućinsku kromatografiju. Uz to optimiziran je protok, gradijent pokretne faze, temperatura kolone i volumen injektiranja. Na trostrukom četveropolnom spektrometru masa određene su vrijednosti m/z iona prekursora i produkata, odnosno prijelazi karakteristični za svaki analit te pripadajuće vrijednosti energija sraza. Optimiziran je i tlak inertnog plina koji omogućuju disocijaciju molekulskog iona kao i ostali parametri spektrometrije masa. Metoda je u konačnici vrednovana određivanjem: specifičnosti, linearnog dijela krivulje umjeravanja, granica dokazivanja i određivanja, točnosti, preciznosti, prikladnosti sustava, robusnosti i stabilnosti otopine analita. Naposljetku, na temelju dobivenih rezultata, donesen je zaključak o prikladnosti metode za korištenje pri analizi realnih uzoraka.This paper provides a theoretical insight into the biologically active substances ibuprofen and carbendazim and how they enter the environment. Additionally, the basic principles of the chromatography techniques in particular UHPLC-DAD-MS/MS are described, as well as the development of the instrumental method. To prepare standard solutions of ibuprofen and carbendazim, methanol was selected as a solvent. The column and the composition of the mobile phase for the liquid chromatograph were selected experimentally. Additionally, the flow, mobile phase gradient, column temperature and injection volume were optimized too. On the triple quadrupole mass spectrometer, the m/z values of precursor ions and product ions, characteristic transitions for each analyte, and the corresponding collision energy values were determined. Inert gas pressure that enables the dissociation of the molecular ions as well as other mass spectrometry parameters were optimized too. The method was validated by determining specificity, the linear part of the calibration curve, limits of detection and quantification, accuracy, precision, system suitability, robustness, and analyte solution stability. Finally, based on the obtained results, a conclusion about the suitability of the method for use in real samples analysis was made
Modeling and optimization of mercury removal on natural and sulfur-impregnated zeolite : diploma thesis
No full textU ovom diplomskom radu provedena je sorpcija Hg(II) na prirodnom (PZ) i sumporom- impregniranom prirodnom zeolitu (SZ) pri različitim početnim koncentracijama. Sorpcijski kapacitet SZ prema Hg(II) iznosio je 1,02 mmol/g što je za 3,6 puta više u usporedbi s PZ (0,28 mmol/g). Sorpcija Hg(II) na zeolitima analizirana je prema Langmuirovom, Freundlichovom i Temkinovom adsorpcijskom modelu. Utvrđeno je da se eksperimentalni rezultati najbolje opisuju Langmuirovim modelom koji je primijenjen u optimizaciji mase u jednostupanjskom i dvostupanjskom istosmjernom šaržnom reaktoru uz uvjet učinkovitosti uklanjanja u iznosu od 99,9 %. Optimalne minimalne mase PZ i SZ izračunate su za sve sustave te je utvrđena značajna ušteda u potrošnji SZ u odnosu na PZ, a posebice kad se primjenjuje dvostupanjski šaržni reaktorIn this diploma thesis, Hg(II) sorption was performed on natural (PZ) and sulfur-impregnated natural zeolite (SZ) at different initial concentrations. The sorption capacity of SZ towards Hg(II) was 1.02 mmol/g, which is 3.6 times higher compared to PZ (0.28 mmol/g). Sorption of Hg(II) on zeolites was analyzed according to the Langmuir, Freundlich and Temkin adsorption models. It was found that the experimental results are best described by the Langmuir model, which was applied in mass optimization in a one-stage and two-stage cross-current batch reactor with a removal efficiency of 99.9%. The optimal minimum masses of PZ and SZ were calculated for all systems, and a significant saving in the consumption of SZ compared to PZ was determined, especially when a two-stage batch reactor is used
Influence of hydrocracking process parameters on product properties in Rijeka oil Refinery : diploma thesis
No full textHidrokrekiranje je tehnološki proces pretvorbe teških naftnih frakcija u visokokvalitetne lakše frakcije poput kerozina i dizela, a uspješnost procesa ovisi o pravovremenom i preciznom praćenju i optimizaciji procesnih parametara. Diplomski rad sagledava ključne procesne varijable Hidrokreking postrojenja Rafinerije nafte Rijeka te njihov utjecaj na učinkovitost katalizatora i kvalitetu proizvoda. Eksperimentalni dio rada uključuje laboratorijske analize sirovina i produkata poput simulirane destilacije, određivanja količine sumpora, bromnog broja, gustoće i indeksa refrakcije. Analizirana je i povezanost tih rezultata s procesnim parametrima kao što su razlika temperature u katalitičkim slojevima i masena prosječna temperatura katalizatora (WABT-a). Dobiveni rezultati ukazuju na povezanost procesnih parametara s kvalitetom produkata i stabilnošću katalizatora. Uočeno je da pad temperature u četvrtom sloju katalizatora i sniženje indeksa refrakcije teške šarže odražavaju promjene u sastavu sirovine i u reakcijskoj učinkovitosti. Kontinuirano praćenje parametara poput WABT-a, optimizacija reakcijskih uvjeta i kvalitetna analiza sirovina mogu značajno doprinijeti poboljšanju učinkovitosti procesa.Hydrocracking is a technological process that converts heavy petroleum fractions into high-quality lighter fractions such as kerosene and diesel. The success of the process depends on timely and precise monitoring and optimization of process parameters. This thesis examines the key process variables of the Hydrocracking Unit at the Rijeka Oil Refinery and their impact on catalyst efficiency and product quality. The experimental part of the thesis includes laboratory analyses of feedstocks and products, such as simulated distillation, sulfur content determination, bromine number, density, and refractive index measurements. The relationship between these results and process parameters, such as the temperature differential across catalytic beds and the weighted average bed temperature (WABT) of the catalyst, was also analyzed. The results indicate a correlation between process parameters, product quality, and catalyst stability. A drop in temperature in the fourth catalytic bed and a decrease in the refractive index of the heavy feedstock were observed to reflect changes in feedstock composition and reaction efficiency. Continuous monitoring of parameters such as WABT, optimization of reaction conditions, and quality analysis of feedstocks can significantly contribute to improving process efficiency.catalytic hydrocracking, catalyst, hydrogenation, desulfurizatio
Electroanalytic application of the coordination compound Co(II) for determination of adrenaline : diploma thesis
No full textAdrenalin ili epinefrin, hormon je i neurotransmiter kojeg luči nadbubrežna žlijezda. Važan je posrednik u stresnim situacijama, poput anksioznosti i depresije, te se koristi kao lijek za stanja poput anafilaksije, krvarenja i srčanog zastoja. U krvi regulira krvni tlak, broj otkucaja srca i metabolizam glikogena. Njegova prisutnost može ukazivati na zdravstvene probleme, a povišene razine javljaju se kod tjelesnih i emocionalnih trauma, te kod karcinoma i Parkinsonove bolesti. Elektrokemijske metode detekcije korištene su za praćenje neurotransmitera povezanih s bolestima zbog svoje brze reakcije, jednostavnosti uporabe i visoke osjetljivosti. Razvijen je novi elektrokemijski senzor za osjetljivo i selektivno određivanje adrenalina koji se temelji na korištenju elektrode od staklenog ugljika (Glassy carbon electrode - GCE) modificirane kobaltovim(II) kompleksom. Prilikom analize stvarnog uzorka, modificirana elektroda pokazala je dobru elektroanalitičku aktivnost (u smislu oksidacije adrenalina), stabilnost, ponovljivost i potencijalnu primjenjivost u komercijalnim farmaceutskim uzorcima. Dobra selektivnost prema adrenalinu također je dokazana i analizom potencijalnih smetnji, gdje na priređenoj elektrodi nisu zamijećene promjene u odzivu osim za vitamin C.Adrenaline, or epinephrine, is a hormone and neurotransmitter secreted by the adrenal gland. It plays an important role as a mediator in stressful situations, such as anxiety and depression, and is used as a medication for conditions like anaphylaxis, bleeding, and cardiac arrest. In the blood, it regulates blood pressure, heart rate, and glycogen metabolism. Its presence can indicate health issues, with elevated levels observed during physical and emotional trauma, as well as in cases of cancer and Parkinson's disease. Electrochemical detection is used to monitor neurotransmitters associated with diseases due to its fast response, ease of use, and high sensitivity. A newly developed electrochemical sensor was used for the sensitive and selective determination of adrenaline, based on a glassy carbon electrode (GCE) modified with a cobalt(II) complex. When analysing a real sample, the modified electrode demonstrated good electroanalytical performance (in terms of adrenaline oxidation), stability, reproducibility, and potential applicability in commercial pharmaceutical samples. The good selectivity towards adrenmaline was also demonstrated by analysing potential interferences, where no changes in response were observed on the prepared electrode, except for vitamin C
Zolite NaX mass impact on copper sorption in a batch reactor with the proppeller impeller : bachelor thesis
No full textU ovom završnom radu ispitan je utjecaj različitih masa NaX zeolita na kinetiku sorpcije bakrovih kationa u šaržnom reaktoru. U eksperimentima su korištene tri različite mase zeolita NaX promjera čestica između 63 i 90 µm. Suspenzije zeolita NaX i otopine bakrovih kationa miješane su pri kritičnoj brzini vrtnje propelerskog miješala, N JS , i konstantnoj temperaturi suspenzije, T = 25 °C. Za ispitivane mase zeolita NaX, kinetička analiza dobivenih kinetičkih eksperimentalnih podataka Blanchardovim i Weber–Morrisovim kinetičkim modelima pokazala je da Blanchardov model bolje opisuje kinetiku sorpcije bakrovih kationa na zeolitu NaX. Zaključeno je kako se proces odvija u kinetičkom području i da je ispitivana reakcija drugog reda te da brzina sorpcije ovisi o masi zeolita.In this work, the influence of different zeolite NaX masses on the kinetics of the copper cation sorption in a batch reactor was examined. Three different masses of zeolite NaX with particle diameters between 63 and 90 µm were used in the experiments. Suspensions of zeolite NaX and copper cations solutions were mixed at the critical propeller impeller speed, N JS , and at the constant temperature of the suspension, T = 25 °C. For the NaX zeolite masses investigated, the kinetic analysis of the obtained experimental data using the Blanchard and Weber– Morris kinetic models showed that Blanchard model better describes the kinetics of copper cations sorption on the NaX zeolite. It was concluded that the process takes place in the kinetic region and that the investigated reaction is a second-order and that the rate of sorption depends on the mass of the zeolite
Hydrogen evolution Ni-Co alloy : bachelor thesis
No full textIspitivano je elektrokatalitičko djelovanje legure Ni 57 Co 43 u 0.5 mol dm -3 vodenoj otopini NaOH na reakciju razvijanja vodika pomoću metoda cikličke voltametrije, linearne polarizacije i elektrokemijske impedancijske spektroskopije. Metodom cikličke voltametrije istraženo je opće elektrokemijsko ponašanje legure Ni 57 Co 43 od područja razvijanja vodika do područja razvijanja kisika. Detektirana su područja potencijala pri kojima dolazi do nastajanja oksida/hidroksida te njihove redukcije. Glavni kinetički parametri: nagib katodnog Tafelovog pravca i gustoća struje izmjene određeni su metodama kvazipotenciostatske linearne polarizacije i elektrokemijske impedancijske spektroskopije. Impedancijski spektri modelirani su prema modificiranom Randlesovom električnom strujnom krugu i određene su vrijednosti elemenata ekvivalentnog električnog kruga. Pomoću Brugove jednadžbe izračunat je kapacitet elektrokemijskog dvosloja iz kojeg je određena hrapavost elektrode. Rezultati dobiveni metodom linearne polarizacije dobro se slažu s rezultatima elektrokemijske impedancijske spektroskopije. Reakcija razvijanja vodika odvija se po mehanizmu Volmer-Heyrovski, a brzinu ukupne reakcije određuje reakcija Heyrovski.The electrocatalytic activity of the Ni 57 Co 43 alloy in 0.5 mol dm -3 NaOH aqueous solutions on the hydrogen evolution reaction was investigated using cyclic voltammetry, linear polarization and electrochemical impedance spectroscopy. The general behaviour of the Ni 57 Co 43 alloy from the area of hydrogen evolution to the area of oxygen evolution was investigated by cyclic voltammetry method. The potential range in which oxides/hydroxides are formed are detected. The main kinetic parameters: the slope of the Tafel line and the current exchange density were determined by linear polarization and electrochemical impedance spectroscopy. Impedance data were modelled according to the modified Randles electric circuit and the values of the elements of the equivalent electric circuit were determined. Using Brug's equation, the capacity of the electrochemical double layer was calculated and the roughness of the electrode was obtained. The results obtained by the linear polarization method are similar to the results of electrochemical impedance spectroscopy. The hydrogen evolution reaction follows the Volmer-Heyrovsky mechanism, and the overall rate determines the Heyrovsky reaction
Analysis of the hybrid process of electrocoagulation and treatment with synthetic zeolite of different particle sizes in treatment of compost leachate obtained by composting using anaerobic process : master thesis
No full textKorištenjem vode nastaju otpadne vode koje je potrebno na određeni način zbrinuti ili podvrgnuti različitim postupcima pročišćavanja prije ispusta u vodna tijela. U procesu kompostiranja nastaju procjedne vode koje su onečišćene organskim i anorganskim štetnim tvarima i kao takve zahtijevaju obradu/tretman prije njihovog ispuštanja. Uslijed industrijalizacije i porasta standarada, nastaju sve veće količine otpadnih voda složenog sastava, za koje treba primijeniti i složenije postupke obrade. Danas je naglasak na razvoju hibridnih procesa koji kombiniraju ili integriraju dva ili više različitih fizikalnih, kemijskih i bioloških postupaka. U ovom radu analizirat će se hibridni proces elektrokoagulacije i sintetskog zeolita različite veličine čestica. Tijekom procesa određeni su sljedeći pokazatelji: pH vrijednost, električna vodljivost, kemijska potrošnja kisika (KPK), mutnoća, ukupni isparni ostatak. Također je provedena i analiza operativnih troškova korištenjem Faradayeva zakona i podataka o utrošku masa elektroda. Rezultati pokazuju da odabir materijala elektrode, veličina čestica korištenog zeolita i gustoće struje utječu na efikasnost uklanjanja KPK i mutnoće, brzinu taloženja te potrošnju elektroda. Polazna otopina je jako složenog sastava, opterećena s velikom količinom teško razgradljive organske tvari koja se nije značajno razgradila u jednostupanjskom postupku hibridnog ECZ. Rješenja su u dvostupanjskim ili višestupanjskim procesima.The use of water creates wastewater that needs to be disposed of in a certain way or exposed to various purification procedures before being discharged into water bodies. In the process of composting, leachate is produced that is contaminated with organic and inorganic harmful substances and as such requires treatment before its discharge. As a result of industrialization, increasing amounts of wastewater with a complex composition are produced, for which should be applied more complex treatment procedures. Today, the emphasis is on the development of hybrid processes that combine or integrate two or more different physical, chemical and biological processes. This paper will analyze the hybrid process of electrocoagulation and synthetic zeolite with different particle size. During the process, the following indicators were determined: pH value, electrical conductivity, chemical oxygen consumption (COD), turbidity, total solids. The results show that the selection of the electrode material, the particle size of the used zeolite and the current density affect the COD and turbidity removal efficiency, the deposition rate and the electrode consumption. The starting solution has a very complex composition, contains a large amount of hard to degrade organic substances that were not significantly degraded in the one step process of the hybrid ECZ. The solutions are in two-stage or multi-stage processes