| Abstract | U današnje vrijeme sve se više suočavamo s posljedicama dugogodišnjeg negativnog utjecaja na okoliš. Povećanjem ljudske populacije raste potreba za energijom odnosno fosilnim gorivima koja se većinom dobivaju iz neobnovljivih izvora energije. Zbog toga su se kao alternativa fosilnim gorivima razvila tekuća biogoriva koja se dobivaju iz obnovljivih izvora energije. Najrašireniju primjenu među biogorivima našao je biodizel. Biodizel dobiven procesom transesterifikacije iz biljnih ulja ili životinjskih masti, sadrži veliki udio glicerola, kojeg je potrebno odvojiti kako bi se zadovoljile direktive Europske unije. Posebno je kao proces pročišćavanja biodizela zanimljiva kapljevinska ekstrakcija pomoću selektivnog otapala. Kao selektivno otapalo najviše se koriste organska otapala koja su toksična, a time i ekološki neprihvatljiva. Stoga se kao njihova zamjena razvijaju zelena otapala, koja su obnovljiva, ne hlapiva, jednostavna za upotrebu te su kemijski i fizički stabilna. Posljednja dva desetljeća veliku pozornost u zelenoj kemiji privukla su eutektička otapala, koja su svoju primjenu pronašla i u procesima pročišćavanja biodizela. U ovome radu provedeno je pročišćavanje biodizela s eutektičkim otapalima u tri tipa mikroekstraktora, iste konfiguracije ali različite širine (250 μm, 350 μm, 500 μm) i volumena (4,15 μL, 5,81 μL, 8,30 μL) mikrokanala. Biodizel korišten u ovom radu je dobiven transesterifikacijom iz svježeg suncokretova ulja uz komercijalni enzim lipazu. Za potrebe provedbe procesa ekstrakcije u mikroekstraktorima sintetizirana su eutektička otapala kolin klorid/glicerol (u molarnim omjerima 1:2,0; 1:2,5; 1:3,0) i kolin klorid/glicerol/voda (u molarnim omjerima 1:1:0,5; 1:1:1,0; 1:1:2,0). Prije provedbe procesa ekstrakcije ovim eutektičkim otapalima su izmjereni gustoća, viskoznost, pH-vrijednost i vodljivost. Ekstrakcija eutektičkim otapalima u mikroekstraktorima pokazala se kao vrlo učinkovita, relativno jeftina i za okoliš prihvatljiva metoda pročišćavanja biodizela. |
| Abstract (english) | Nowadays we are facing more and more with the repercussions of a long-term negative influence on the environment. With an increase of human's population, there is also growing need for energy, i.e. fossil fuels which are mainly produced from non-renewable energy sources. Due to that, fluid biofuel produced from renewable energy sources appeared as a sort of alternative. Biodiesel has found the broadest use among the other biofuels. Biodiesel is produced by the transesterification from biooils or animal fat and it contains large amount of glycerol which must be separated in order to satisfy the directives of the European Union. Specially interesting as a biodiesel purification process is a liquid extraction with a selective solvent. As a selective solvent, there can be used mostly organic solvents which are known to be toxic and therefore ecologically unacceptable. As a result, green solvents have been developed as their replacement. Green solvents are renewable, non-volatile, chemically and physically stable and easy to use. During the last two decades, deep eutectic solvents, which found their application in the process of biodiesel refining, have received huge attention in the green chemistry. In this thesis biodiesel refining with deep eutectic solvents was carried out in three types of microextractor, with the same configuration but different width (250 μm, 350 μm, 500 μm) and volume (4,15 μL, 5,81 μL, 8,30 μL) of microchannels. Biodiesel used in this study was produced by the transesterification of the fresh sunflower's oil with the commercial enzyme lipase. Different deep eutectic solvents such as choline chloride/glycerol (in molar ratio 1:2,0; 1:2,5; 1:3,0) and choline chloride/glycerol/water (in molar ratio 1:1:0,5; 1:1:1,0; 1:1:2,0) were synthesised and used for extraction in microextractors. Before extraction process density, viscosity, pH value and conductivity of all syntesised deep eutectic solvents were measured. Extraction in microextractors by deep eutectic solvents is very effective, inexpensive and environmentally acceptable for biodiesel purification. |
