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The isolation of keratin from poultry feathers using subcritical water was studied in a batch reactor at temperatures (120–250 ◦C) and reaction times (5–75 min). The hydrolyzed product was characterized by FTIR and elemental analysis, while the molecular weight of the isolated product was determined by SDS-PAGE electrophoresis. To determine whether disulfide bond cleavage was followed by depolymerization of protein molecules to amino acids, the concentration of 27 amino acids in the hydrolysate was analyzed by GC/MS. The optimal operating parameters for obtaining a high molecular weight protein hydrolysate from poultry feathers were 180 ◦C and 60 min. The molecular weight of the protein hydrolysate obtained under optimal conditions ranged from 4.5 to 12 kDa, and the content of amino acids in the dried product was low (2.53% w/w). Elemental and FTIR analyses of unprocessed feathers and dried hydrolysate obtained under optimal conditions showed no significant differences in protein content and structure. Obtained hydrolysate is a colloidal solution with a tendency for particle agglomeration. Finally, a positive influence on skin fibroblast viability was observed for the hydrolysate obtained under optimal processing conditions for concentrations below 6.25 mg/mL, which makes the product interesting for various biomedical applications.

The food and plant industry generate large amounts of wastes or by-products annually around the world from a variety of sources. Improper management and illegal dumping of waste, particularly hazardous and toxic waste, possess increasing threats to the environment and human health. Tobacco waste is a by-products produced in large quantities during processing of tobacco and in most cases, represents an inefficient use of valuable compounds. Tobacco waste (type: scrap) in this study was obtained from “Fabrika Duhana Sarajevo” from Bosnia and Herzegovina. A series of operational parameters of supercritical CO2 (SC- CO2) extraction of tobacco waste (pressure: 100– 300 bar, temperature: 40–80 °C), were investigated in a laboratory scale apparatus in order to get extracts rich in nicotine. The CO2 mass flow rate was kept constant during the process. From reused tobacco waste (after SC-CO2 extraction), subcritical water extraction (SWE) under selected conditions (solvent/solid ratio: 28 mL/g, temperature: 150 ˚C, time: 23 min) was sequentially performed to obtain the extracts rich in phenolic compounds. The content of bioactive compounds was determined using High Performance Liquid Chromatography (HPLC) and by gas chromatography (GC-MS) Obtained extracts of tobacco waste after SC-CO2 extraction were characterized by high levels of nicotine, and after SWE extracts were characterized by a high content of phenolic compounds, considerable amounts of nicotinic acid and nicotinamide and reduced content of nicotine. Also, presence of 5- HMF, furfural and 5-MF was detected in SWE extracts.

The influence of pressure and treatment time on cells disruption of different black yeasts and on activities of extracted proteins using supercritical carbon dioxide process was studied. The cells of three different black yeasts Phaeotheca triangularis, Trimatostroma salinum, and Wallemia ichthyophaga were exposed to supercritical carbon dioxide (SC $CO_2$) by varying pressure at fixed temperature (35°C). The black yeasts cell walls were disrupted, and the content of the cells was spilled into the liquid medium. The impact of SC $CO_2$ conditions on secretion of enzymes and proteins from black yeast cells suspension was studied. The residual activity of the enzymes cellulase, $beta$-glucosidase, $alpha$-amylase, and protease was studied by enzymatic assay. The viability of black yeast cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration in the suspension was determined on UV–Vis spectrophotometer at 595 nm. The release of intracellular and extracellular products from black yeast cells was achieved. Also, the observation by an environmental scanning electron microscopy shows major morphological changes with SC $CO_2$-treated cells. The advantages of the proposed method are in a simple use, which is also possible for heat-sensitive materials on one hand and on the other hand integration of the extraction of enzymes and their use in biocatalytical reactions.

Onesnaževanje okolja s težkimi kovinami in reševanje le te problematike na učinkovit in hkrati ekonomsko sprejemljiv način, predstavlja vedno večji izziv v današnjem času. V diplomski nalogi smo preučevali adsorpcijske lastnosti bentonita za adsorpcijo kovinskih ionov (železo, baker, svinec) iz vodne raztopine. Masne koncentracije kovinskih ionov v raztopini smo določili z optično emisijsko spektroskopijo (ICP OES). Prav tako smo preučili karakteristike samega bentonita (velikost delcev, zeta potencial, specifična površina, volumen por). Karakterizacija je pokazala, da je v našem vzorcu bentonita povprečni zeta potencial - 0,257 mV in povprečna velikost delcev 1657 nm. Ugotovili smo, da s spreminjanjem pH raztopin Fe2+, Cu2+ in Pb2+ ionov, bentonit najbolje adsorbira pri pH vrednosti 7. Spreminjali smo tudi koncentracije samih raztopin z Fe2+, Cu2+ in Pb2+ ionov v območju od 1 mM do 13 mM in izmerili, da ima bentonit največjo kapaciteto pri koncentraciji 13 mM. Prav tako smo preizkusili medsebojni vpliv ionov na adsorpcijo in ugotovili, da je učinkovitost adsorpcije vseh treh ionov nad 99 %. Iz rezultatov diplomskega dela lahko sklepamo, da je bentonit odlična izbira za odstranjevanje železovih, bakrovih in svinčevih ionov iz vode. Heavy metal pollution and how to solve this problem in an efficient and economically acceptable way, represents one of the biggest problems in our modern world. In diploma thesis, we examined adsorption capacity of bentonite for the adsorption of metal ions (iron, copper, lead) from aqueous solution. The mass concentrations of the metal ions in the solution has been determinated by optical emission spectroscopy (ICP OES). Furthermore, the characteristics of bentonite (particle size, zeta potential, specific surface area, pore volume) has been examined. Characterization showed that for our sample of bentonite, the average zeta potential was 0.257 mV and the average particle size was 1657 nm. We observed that by changing the pH of Fe2+, Cu2+ and Pb2+ ion solutions, bentonite absorbs best at pH value of 7. By varying the concentration of the solutions of Fe2+, Cu2+ and Pb2+ ions in range from 1 mM to 13 mM it was found that bentonite has the highest capacity at a concentration of 13 mM. In addition, we investigated the interactions of the ions in solution and their influence on adsorption and we realised that the adsorption efficiency of all three ions was above 99 %. The results of the thesis lead to the conclusion, that bentonite is an excellent choice for the removal of iron, copper and lead ions from water.

Diplomsko delo je rezultat preučevanja adsorpcije težkih ionov Pb2+, Cu2+ in Fe2+ na zeolit. Ker so ti ioni zelo močni onesnaževalci okolja, se pojavlja vprašanje kako zaščititi naravo pred njihovimi škodljivimi vplivi. Ena iz med možnosti je adsorpcija ionov na močen adsorbent, kar je v našem primeru zeolit. Tako je bistveno, da dobro spoznamo zeolit, preučimo njegovo strukturo in lastnosti, ter nato z različnimi kemijskimi analizami določimo, kakšne zmožnosti adsorpcije ima zeolit. Namen diplomske naloge je bil določiti adsorpcijske lastnosti zeolita v raztopini za adsorpcijo ionov težkih kovin ( Cu2+, Fe2+, Pb2+ ), določiti masne koncentracije kovinskih ionov z optično emisijsko spektroskopijo (ICP OES), ter preučiti specifiko samega zeolita (zeta potencial, specifična površina, velikost delcev). Za ugotavljanje adsopcijskih lastnosti zeolita smo spreminjali dva ključna parametra, koncentracijo raztopine težkih ionov, ter pH raztopine. S spreminjanjem teh parametrov smo prišli do ugotovitve, da so najbolj optimalni pogoji za adsorpcijo pri koncentraciji 13 mM in pri pH vrednosti 7. S preiskovanjem vpliva koncentracije težkih ionov na adsorbent smo ugotovili, da uspešnost adsorpcije pri višji koncentraciji upada, izjema je le baker. Pri spreminjanju pH vrednosti, pa se je izkazalo, da pH nima takšen velik vpliv na adsorpcijo kot jo ima koncentracija, saj smo ugotovili, da se adsorpcijska sposobnost malo zmanjša le pri zelo nizki pH vrednosti ( pH = 2,5 ). Ugotavljali smo tudi medsebojni vpliv ionov na učinkovitost adsorpcije ionov na zeolit, pri čemer se je izkazalo, da mešanica ionov v raztopini dobro vpliva na adsorpcijo, saj je bila v našem primeru učinkovitost adsorpcije za vse tri ione nad 99%. The diploma thesis is the result of studying the adsorption of heavy metal ions of Pb2+, Cu2+ and Fe2+ on zeolite. Since this ions are very powerful pollutants of the environment, the question arises as how to protect nature from their harmful effects. One of the possibilities is the adsorption of ions on a strong adsorbent, which in our case is zeolite. It is essential to get to know the zeolite well, to study its structure and properties, and then to determine, through various chemical analyzes, what is the zeolite's adsorption capacity. The purpose of this thesis was to determine the adsorption properties of zeolit for adsorption of heavy metal ions (Cu2+, Fe2+, Pb2+) in solution, to determine the mass concentrations of metal ions by optical emission spectroscopy (ICP OES), and to study the specificity of the zeolite itself (zeta potential, specific surface area, particle size). In order to determine the adsorption properties of zeolite, two key parameters, the concentration of the heavy metal ions in solution and the pH of the solution, have been studied. By changing these parameters, the most optimal conditions for adsorption were determined at a concentration of 13 mM and at a pH value of 7. By examining the influence of the concentration of heavy metal ions on the adsorbent, we found that the adsorption efficiency at a higher concentration decreases, with the exception of copper. When changing the pH value, it turned out that pH did not have as much effect on adsorption as the concentration, since we found that the adsorption efficiency decreased only at very low pH (pH = 2.5). We also investigated the interaction of ions on the adsorption efficiency of the zeolite, which showed that the mixture of ions in solution had a good effect on adsorption, since in our case the adsorption efficiency for all three ions was above 99%.

Namen in cilj diplomskega dela je bil raziskati hidrotermično degaradacijo odpadne embalaže iz polipropilena (PP) s pomočjo superkritične vode ter določiti nastale produkte. Izvedena je bila primerjava pisanega in brezbarvnega PP. Proučevali smo vpliv procesnih parametrov, kot so tlak, temperatura, razmerje voda/PP na potek in kinetiko reakcij razgradnje odpadne embalaže iz PP v superkritični vodi. PP je trd termoplastičen polimer z gostoto med 0,9 in 0,92 g/cm3. V mnogih pogledih je podoben polietilenu, vendar z večjo mehansko in natezno trdnostjo ter toplotno stabilnostjo. Odporen je proti polarnim topilom, kislinam, raztopinam soli in olju ter neodporen proti kloriranim ogljikovodikom. Zaradi dobrih mehanskih in fizikalnih lastnosti je eden izmed najbolj zastopanih polimerov v svetu. Uporablja se v različne namene, kot so folije, plastenke za mineralno vodo, povratne plastenke, v ploščah, ceveh, avtomobilski industriji ter v beli tehniki. Zaradi velike zastopanosti tega polimera in vpliva ter kopičenja v okolju smo izvedli hidrotermično degradacijo pisanega PP in brezbarvnega PP. Hidrotermično degradacijo smo izvajali v visokotemperaturnem in visokotlačnem šaržnem reaktorju pri temperaturah 425 °C in 450 °C ter reakcijskih časih od 15 do 240 min. Nastale produkte smo filtrirali ter analizirali s pomočjo plinske kromatografije/masne spektrometrije GC/MS ter določili vsebnost celotnega organskega ogljika (TOC). Ugotovili smo, da je največji izkoristek plina nastal pri 240 min degradaciji – tako barvnega kot brezbarvnega PP v superkritični vodi – najmanj pa ga je nastalo pri 15-minutni degradaciji. Najbolj zastopane komponente so metan, etan, propan, izobutan ter ogljikov dioksid. Dokazali smo, da je največji donos alkanov prisoten le pri višji temperaturi. Majhne razlike v vsebnosti alkanov, ki so prisotni pri isti temperaturi, lahko pripišemo aditivom ter različnim primesem, ki jih vsebuje pisani PP. Izkoristki nastale oljne faze s podaljševanjem reakcijskega časa upadajo, saj se dolgi ogljikovodiki cepijo na krajše. The purpose of the following work was to investigate the hydrothermal degradation of polypropylene waste packaging (PP) using supercritical water, and determine the resulting products. A comparison of a colored and colorless PP has been done. The impact of process parameters, such as pressure, temperature and water/PP proportion on the course of reaction and the kinetics of the decomposition of waste packaging from PP in supercritical water has been studied. Polypropylene (PP) is a solid thermoplastic polymer with density between 0.9 and 0.92 g/cm3. It is quite similar to polyethylene, but with greater mechanical and tensile strength and thermal stability. It is resistant to polar solvents, acids, saline and oil solutions and it is not resistant to chlorinated hydrocarbons. Because of its good mechanical and physical properties, it is one of the most represented polymers in the world. It is used for various purposes, such as foils, mineral water bottles, return bottles, plates, pipes, automotive and white goods. Due to the high abundance of this polymer and his influence and accumulation in the environment, hydrothermal degradation of the coloured PP and colorless PP has been investigated. Hydrothermal degradation was carried out in a high temperature and high pressure batch reactor at temperatures of 425 °C and 450 °C and reaction time of 15–240 min. The resulting products were filtered and analyzed by gas chromatography/GC and MS/mass spectrometry and we determined the total organic carbon content (TOC) has been determined. We found that the maximum gas yield was obtained at 240 min degradation of both the coloured and the colorless PP in supercritical water, and the minimum yield was obtained at 15 minute degradation. The most represented components are methane, ethane, propane, isobutane and carbon dioxide. The results of analyses showed that the maximum yield of alkanes is obtained only at a higher temperature. The small differences in the amount of obtained alkanes at the same temperature can be attributed to additives which are present in a coloured PP. The yield of the resulting oil phase decreases with the prolongation of the reaction time, beacuse the long hydrocarbons are splited into shorter molecules.

Razgradnja odpadne embalaže je v današnjem času zelo aktualna tema, saj se delež komunalnih in industrijskih odpadkov iz dneva v dan povečuje. V zadnjem času so zato raziskave na področju alternativnih, okolju prijaznih metod recikliranja odpadkov zelo intenzivne. Polietilen (PE) predstavlja najbolj razširjeno plastiko na svetovni ravni, ki se nahaja predvsem v embalaži, kot so plastične vrečke, folije, plastenke, tudi v kozmetičnih izdelkih, prehrambeni industriji in energetiki. Sub- in superkritična voda je okolju prijazno topilo in odličen reakcijski medij za depolimerizacijo plastike v različne uporabne produkte. S tem namenom smo v diplomski nalogi proučevali razgradnjo odpadne barvne embalaže iz PE v superkritični vodi (SCW). Postopek smo izvajali v visokotlačnem, visokotemperaturnem šaržnem reaktorju, kjer smo odpadni barvni PE v razmerju z vodo 1/5 (g/mL) izpostavljali temperaturam 425 ºC in 450 °C v časovnih intervalih od 15 do 240 minut. Pri razgradnji odpadne barvne embalaže iz PE v SCW smo dobili štiri faze: oljno fazo ali vosek, vmesno, vodno ter plinsko fazo. Produkte v oljni in plinski fazi smo analizirali z GC/MS metodo, v vodni fazi pa smo določevali totalni ogljik (TC). Ugotovili smo, da se odpadna barvna embalaža iz PE v SCW ni popolnoma razgradila pri temperaturi 425 ºC pri časih 15 in 30 minut. Nastala oljna faza je vsebovala veliko ogljikovodikov, kjer so pri nižjih temperaturah in krajših časih prevladovali dolgi ogljikovodiki, pri višjih temperaturah in daljših časih pa so se pojavljali aromatski ogljikovodiki. Plinska faza je vsebovala različne pline, predvsem alkane in alkene. The decomposition of packaging waste is a very popular topic nowadays because the quantity of municipal and industrial waste is fastly growing. Lately, intensive research work has been devoted to alternative and eco-friendly methods of recycling. Polyethylene (PE) is the most widely used plastic in the world, which is mainly found in packaging, such as plastic bags, foils, bottles, even in cosmetic products, in food industry and energy. Sub- and supercritical water is an eco-friendly solvent and a great reaction medium for the depolymerization of plastic into various useful products. For this purpose, the degradation of colored packaging waste of PE in supercritical water (SCW) has been studied. The procedure was carried out in a high pressure, high temperature batch reactor at the temperatures of 425 °C and 450 °C. The mixture of coloured PE waste and water in a ratio 1/5 (g/mL) was exposed at various intervals ranging from 15 to 240 minutes. During the decomposition of colored packaging waste of PE in SCW four phases were obtained: oil phase or wax, intermediate, water and gas phase. The degradation products in the oil and gas phases were analyzed by gas cromatography and mass spectrometry. The content of total carbon was determined in the aqueoous phase. It was found that colored packaging waste of PE was not completely decomposed at 425 °C for 15 and 30 minutes. The obtained oil phase was composed of many hydrocarbons, where long-term hydrocarbons predominated at lower temperatures and shorter times, and aromatic hydrocabrons appeared at higher temperatures and longer times. The gas phase contained various gases, especially alkanes and alkenes.

Polietilen tereftalat (PET) sodi med najbolj razširjene termoplastične smole. Ima dobre mehanske, toplotne in kemijske lastnosti. Uporabljamo ga predvsem za izdelavo embalaže za pitno vodo in živila. PET je nerazgradljiva plastika, zato se ga vedno več nabira v naravi. Zaradi negativnih posledic kopičenja PET v naravi, dajemo dandanes vse večji pomen ločevanju in recikliranju odpadne PET embalaže. PET lahko recikliramo na več načinov. Eden izmed najučinkovitejših načinov je kemijsko recikliranje s hidrotermično degradacijo. Namen diplomskega dela je bil preučiti recikliranje odpadne PET embalaže s pod in nadkritično vodo. Pod- in nadkritična voda je odličen reakcijski medij za degradacijo odpadne PET embalaže. Odpadna PET embalaža namreč po degradaciji v pod in nadkritičnih vodi razpade na monomere. Glaven monomer, ki nastane je tereftalna kislina (TPA). TPA predstavlja glavno korist recikliranja, iz nje namreč lahko ponovno izdelamo PET. Eksperimentalni del hidrotermične degradacije odpadne PET embalaže smo izvajali v visokotlačnem in visokotemperaturnem šaržnem reaktorju v pod in nadkritični vodi. Reakcije smo izvajali pri štirih različnih temperaturah 250, 300, 350 in 400 °C in reakcijskem času 1, 10 in 30 minut. Nastale produkte hidrotermične degradacije smo analizirali s HPLC, FT-IR in GC-MS metodami. Analize produktov hidrotermične degradacije odpadne PET embalaže so pokazale, da dobimo najvišji izkoristek glavnega produkta TPA pri podkritičnih pogojih, in sicer pri temperaturi 300 °C in času 30 minut. Izkoristek TPA pri degradaciji odpadne barvne PET embalaže je znašal 85%. Za primerjavo izkoristkov smo izvedli še hidrotermično degradacijo brezbarvne odpadne PET embalaže pri enakih pogojih. Dobljen izkoristek je znašal 90%. Z višanjem temperature v nadkritično območje se je izkoristek TPA zniževal, zaradi nastajanja sekundarnih produktov. Polyethylene terephthalate (PET) is one of the most widely used types of plastic resins. It has good mechanical, thermal and chemical properties. We use it primarily for the production of packaging for drinking water and food. PET is non-degradable plastic, which is why it has accumulated so much in the nature. Because of the negative consequences of the accumulation of PET in the nature, it is highly important to recycle PET packaging waste. PET can be recycled in several ways. One of the most effective solution is chemical recycling with hydrothermal degradation. The purpose of the diploma thesis was to examine the recycling of PET packaging waste with sub- and supercritical water. Sub- and supercritical water is an excellent reaction medium for the degradation of PET packaging waste, that can be decomposed into monomers. The main monomer that is produced is terephthalic acid (TPA). TPA is considered to be the main benefit of recycling because it is the compound that can be used fort the synthesis of PET again. The experimental part of the hydrothermal degradation of PET packaging waste was carried out in the high-pressure and high-temperature batch reactor in the sub- and supercritical water. Reactions were carried out at four different temperatures of 250, 300, 350 and 400 °C, and the reaction time was 1, 10 and 30 minutes. The resulting hydrothermal degradation products were analyzed by HPLC, FT-IR and GC-MS methods. The analysis of products of hydrothermal degradation of PET packaging waste showed that the highest yield of the main TPA product was obtained under subcritical conditions at a temperature of 300 °C and 30 minutes of reaction time. The yield of TPA obtained by degradation of coloured PET packaging waste was 85%. For comparison, hydrothermal degradation was carried out under the same conditions using colourless PET packaging waste. The obtained yield of TPA was 90%. By increasing the temperature to the supercritical area, the TPA yield decreased due to the formation of secondary products.