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Modeliranje kontinuirane farmaceutske sinteze u svrhu vođenja procesa
No full textThis work investigates the modelling and sensitivity analysis of the Simmons-Smith reaction, a critical process for the synthesis of cyclopropanes, in a plug flow reactor (PFR) for continuous pharmaceutical synthesis. Using dibromomethane and cyclohexene as substrate, the study replaces the conventional copper catalyst with grated zinc, which represents a simplified and potentially more sustainable approach. A dynamic model was developed to predict the reaction behaviour under different operating conditions, such as temperature and flow rate, allowing better control of the reaction dynamics. The analysis showed that higher temperatures and slower flow rates improve reactant conversion and product yield, while lower temperatures and higher flow rates reduce reaction efficiency. Sensitivity tests revealed a lag between the changes in the input variables and the observable effects, emphasising the importance of understanding transient dynamics. The models for two experimental setups showed agreement with the observed data, although some deviations highlighted the need for refinements, particularly in thermal and kinetic representations.
The results emphasise the potential of PFR systems for scalable, efficient and controlled organometallic reactions. This study advances the application of continuous flow systems in pharmaceutical production and promotes sustainable synthesis technologies.Ovaj diplomski rad istražuje modeliranje i analizu osjetljivosti Simmons-Smithove reakcije, važnog procesa za sintezu ciklopropana, unutar idealnog reaktora s čepolikim strujanjem za kontinuiranu farmaceutsku sintezu. Koristeći dibromometan i cikloheksen kao supstrat, u ovom radu se zamjenjuje bakar kao konvencionalni katalizator s cinkom nudeći pojednostavljeni i potencijalno održiviji pristup. Razvijen je dinamički model za predviđanje vladanja procesa reakcije pod različitim radnim uvjetima, kao što su temperatura i protok. Analiza je otkrila da više temperature i manji protoci povećavaju konverziju reaktanata i prinos proizvoda. Testiranje osjetljivosti utvrdilo je kašnjenje između promjena parametara i vidljivih učinaka, naglašavajući važnost razumijevanja dinamičkog vladanja procesa.
Modeli koji opisuju provedene eksperimente donekle prate eksperimentalne rezultate, iako su neka odstupanja istaknula potrebu za poboljšanjima. Dobiveni rezultati naglašavaju potencijal ovakvih sustava za skalabilne, učinkovite i kontrolirane organometalne reakcije.
Ovo istraživanje unaprjeđuje primjenu protočnih reaktorskih sustava u farmaceutskoj proizvodnji, promičući održive tehnologije sinteze
Preparation of mesoporous glasses via soft template method
No full textU ovom radu opisana je sinteza mezoporoznog kalcij-silikatnog stakla metodom mekog predloška temeljenog na blok kopolimeru P123. Uređena mezostruktura mekog predloška poslužila je za nanošenje gela nastalog sol-gel procesom, a uklanjanjem mekog predloška kemijskom i termičkom obradom kserogela nastala je uređena mezoporozna struktura stakla. Dobiveni uzorci analizirani su PXRD, FTIR, DSC, BET i BJH, SEM-EDS i TEM analizom, pri čemu je utvrđena vrlo visoka specifična površina koja se značajno očuvala i nakon prešanja u pelete. Praškasti uzorak sastoji se od aglomeriranih čestica nepravilnog do sferičnog oblika s izraženim međučestičnim porama dok uzorak prešan u pelete ima zbijenu strukturu i smanjene međučestične prostore, iako je zadržao određenu poroznost. Nakon kontakta sa SBF-om, na površini peleta nastala je slojevita, hrapava struktura, što upućuje na moguće taloženje komponenti SBF-a na površinu stakla.This study describes the synthesis of mesoporous calcium-silicate glass using a soft-templating method based on the block copolymer P123. The ordered mesostructure of the soft template served as a scaffold for gel deposition via the sol-gel process, and its subsequent removal through chemical and thermal treatment of the xerogel resulted in an ordered mesoporous glass structure. The obtained samples were characterized by PXRD, FTIR, DSC, BET, BJH, SEM-EDS and TEM analyses, confirming a very high specific surface area, which remained largely preserved even after pellet compaction. The powder sample is consisted of agglomerated particles with irregular to spherical morphology and pronounced interparticle porosity, whereas the pelletized sample exhibited a denser structure with reduced interparticle voids while retaining same porosity. Upon immersion in simulated body fluid (SBF), a layered, rough structure formed on the pellet surface, suggesting potential deposition of SBF constituents on the surface of the glass
Influence of methacrylate polymer additives synthesized in biofuel on the low-temperature properties of diesel fuel
No full textS obzirom na sve veće zahtjeve za poboljšanjem performansi dizelskog goriva, osobito u hladnim uvjetima rada, istraživanje i razvoj inovativnih aditiva za poboljšanje niskotemperaturnih svojstava ključan su aspekt razvoja moderne energetske industrije.
Ovaj rad istražuje utjecaj metakrilatnih polimernih aditiva sintetiziranih u biogorivu na niskotemperaturna svojstva dizelskog goriva. Metakrilatni polimeri, pokazali su se kao učinkovita rješenja zbog svojih kemijskih svojstava koja omogućuju stabilizaciju i poboljšanje fluidnosti goriva pri niskim temperaturama. Metakrilatni aditivi, sintetizirani u biogorivima, ne samo da poboljšavaju operativne karakteristike dizelskog goriva, već i pridonose održivosti smanjenjem potrebe za fosilnim resursima. Istraživanje uključuje sintezu ukupno šest metakrilatnih aditiva, na osnovi benzil metakrilata uz oktadecil, dodecil te 2-(tert-butilamino) etil metakrilata. Cilj rada bio je sintetizirani polimerne aditive u svrhu poboljšanja niskotemperaturnih svojstava. Polimerni aditivi su sintetizirani u biodizelu kao biootapalu, a rad istražuje i utjecaj različitih prosjeka molekulskih masa na niskotemperaturna svojstva. Upoređivana je i sinteza s komercijalnom reakcijom u toluenu. Polimeri su sintetizirani radikalskom polimerizacijom u otopini toluena uz Peroxan PO 70 kao inicijator te uz n-dodecil merkaptan kao prijenosnik lanca. Sintetiziranim polimerima potvrđena je struktura pomoću 1H nuklearne magnetske rezonancije. Kromatografijom na propusnom gelu određen je prosjek molekulskih masa polimernih aditiva. Nadalje, formulacijama dizelskog goriva s aditivima određena je i gustoća i viskoznost. Toplinska svojstva, odnosno temperatura kristalizacije i promjena entalpije kristalizacije aditiva te formulacija aditiva s dizelskim gorivom ispitana su metodom diferencijalne pretražne kalorimetrije. Provedeno je mjerenje temperatura tecišta smjesa aditiviranog dizelskog goriva, a praćen je i utjecaj aditiva na morfologiju i veličinu kristala n-parafina pomoću mikroskopa s polarizacijom dok se smjesa hladila postoljem s hlađenjem.In response to the increasing demands for enhancing the performance of diesel fuels, particularly under cold operating conditions, exploring innovative additives to improve low-temperature properties has become a crucial aspect of modern energy industry development. This study focuses on the impact of metacrylate-based polymer additives synthesized in biodiesel on the low-temperature properties of diesel fuel. Metacrylate polymers are effective solutions due to their chemical properties that facilitate the stabilization and improvement of fuel fluidity at low temperatures. Metacrylate additives, synthesized in biodiesel, not only enhance the operational characteristics of diesel fuel but also contribute to sustainability by reducing the reliance on fossil resources. The research involves the synthesis of a total of six methacrylate additives based on benzyl methacrylate, along with octadecyl, dodecyl, and 2-(tert-butylamino) ethyl methacrylate. The aim of the study was to synthesize polymer additives for the purpose of improving low-temperature properties. Polymeric additives were synthesized in biodiesel as a biosolvent, and the work also investigates the influence of different distribution of molecular masses on low-temperature properties. The synthesis was also compared with a commercial reaction in toluene. The polymers were synthesized by radical polymerization in a toluene solution using Peroxan PO 70 as the initiator and N-dodecyl mercaptan Š-18DTND719 as the chain transfer agent. The structure of the synthesized polymers was confirmed using 1H Nuclear magnetic resonance. Gel permeation chromatography was used to determine the molecular weight range of the polymer additives. Additionally, the density and viscosity of the diesel fuel formulations with additives were also measured. The thermal properties, specifically the crystallization temperature and the change in crystallization enthalpy of the additives and their formulations with diesel fuel, were examined using differential scanning calorimetry.
The pour point temperatures of the diesel fuel mixtures with additives were measured, and the effect of the additives on the morphology and size of n-paraffin crystals was monitored using a polarized light microscope while the mixture was cooled by a cooling stage
Synthesis and structural characterization of new quinoline and triazole derivatives with potential antitrypanosomal activity
No full textCilj ovog rada je sinteza novih derivata kinolina i triazola i njihovih Re(I) trikarbonilnih kompleksa te sinteza derivata kinolina i heterocikličkih hidrazona. Derivati kinolina i triazola (9a−9c, 10a, 11a−11c) dobiveni su mehanokemijskom sintezom kojom je provedena reakcija cikloadicije azida i alkina katalizirana Cu(I). Spojevi 9a i 10a nadalje su korišteni kao ligandi za kompleksiranje s Re(I) pentakarbonil-kloridom (9aRe, 10aRe). 2-(trifluormetil)kinolin-4-oli dobiveni su Conrad–Limpachovom ciklokondenzacijom te su, kao i 3-nitro-1,2,4-triazol, potom prevedeni u odgovarajuće alkine i azide. Klik reakcija alkina i azida provedena je primjenom azidnih kinolina i N-propargiliranog 1,2,4-triazola te korištenjem O-alkiliranih kinolina i azidnog triazola. Derivati kinolina i hidrazona (15a−15d, 16a−16d) dobiveni su nukleofilnom adicijom hidrazinskih kinolina na karbonilnu skupinu heterocikličkih aldehida, praćenom dehidratiranjem. Strukture spojeva potvrđene su spektroskopijom 1H i 13C NMR, karakteristične apsorpcijske vrpce potvrđene su IR spektroskopijom, a strukture derivata kinolina i hidrazona dodatno su potvrđene visokoučinkovitom spektrometrijom masa. Biološka ispitivanja novosintetiziranih spojeva (9a−9c, 10a, 11a−11c, 9aRe, 10aRe, 15a−15d, 16a−16d) su u tijeku.The aim of this work is the synthesis of novel quinoline and triazole derivatives as well as their Re(I) tricarbonyl complexes. Preparation of quinoline-based hydrazone derivatives was also performed. Quinoline triazole derivatives (9a−9c, 10a, 11a−11c) were synthesized by Cu(I)-catalyzed azide–alkyne cycloaddition using mechanochemistry. Compounds 9a and 10a served as ligands for complexation with Re(I) pentacarbonyl chloride, yielding metal complexes 9aRe and 10aRe. 2-(Trifluoromethyl)quinolin-4-ols were synthesized through Conrad–Limpach cyclocondensation, and together with 3-nitro-1,2,4-triazole, were transformed into corresponding alkynes and azides. Click reactions were performed by reaction of azido-substituted quinolines and N-propargylated 1,2,4-triazole, and O-alkylated quinolines and azido triazoles. Hydrazone derivatives (15a−15d, 16a−16d) were obtained via nucleophilic addition of quinoline hydrazines to the carbonyl group of heterocyclic aldehydes, followed by dehydration. The structures of the synthesized compounds were confirmed by ¹H and ¹³C NMR spectroscopy, characteristic absorption bands were identified by IR spectroscopy and the structures of the quinoline hydrazone derivatives were further confirmed by high resolution mass spectrometry. Biological evaluation of the newly synthesized compounds (9a−9c, 10a, 11a−11c, 9aRe, 10aRe, 15a−15d, 16a−16d) is currently underway
Influence of the reaction parameters on the biodiesel synthesis from palm oil and selected straight-chain alcohols
No full textKroz posljednjih nekoliko desetljeća znanost se intenzivnije posvetila razvoju biogoriva s ciljem smanjenja onečišćenja okoliša uzrokovanog izgaranjem fosilnih goriva. Isto tako, porast broja svjetske populacije, brza industrijalizacija, urbanizacija, samo su neki od čimbenika koji uzrokuju rastuću potražnju za energijom i time potiču sve veću upotrebu fosilnih goriva. Kako su fosilna goriva neobnovljivi izvori energije, istraživanja su usmjerena na gorivo koje bi potjecalo isključivo od obnovljivih izvora. Kao dobra alternativa pokazao se biodizel zbog svoje ekološki prihvatljive prirode. Dobiva se katalitičkom transesterifikacijom – reakcijom biosirovine (biljnih ulja i životinjskih masti) s alkoholom uz prisutnost katalizatora. Sastavni dio masti i ulja su trigliceridi – esteri alkohola glicerola i viših masnih kiselina koji sudjeluju u reakciji transesterifikacije s alkoholom. Nastaju smjese alkilnih estera masnih kiselina (biodizel) i alkohol glicerol kao sporedni produkt. U ovom je radu biodizel sintetiziran transesterifikacijom iz palminog ulja kao glavne biosirovine te odabranih ravnolančanih alkohola: 1-propanola, 1-butanola, 1-pentanola, 1-heksanola, 1-oktanola uz prisutnost baznog katalizatora - kalijeva hidroksida (KOH), budući da svojstva primjene biodizela ovise o strukturi reaktanata korištenih u sintezi. Praćeni su utjecaji određenih parametara na reakciju sinteze, a to su: reakcijsko vrijeme (5, 15, 60 minuta), temperatura
(60 °C), molarni omjer alkohola i ulja (5:1 i 10:1) i maseni udio katalizatora (1 mas.% KOH i 3 mas.% KOH). Osim utjecaja navedenih parametara, praćen je i utjecaj molekulske mase alkohola na iskorištenje reakcije. S obzirom na navedene alkohole, u reakciji sinteze biodizela nastaju propilni, butilni, pentilni, heksilni i oktilni esteri masnih kiselina. Dobiveni rezultati pokazuju da reakcijsko vrijeme ima vrlo malo ili nimalo utjecaja na iskorištenje. Povećanje masenog udjela katalizatora i molarnog omjera alkohola i ulja generalno dovodi do većeg iskorištenja sinteze biodizela. S povećanjem molekulske mase alkohola pada polaritet alkohola, a u konačnici i alkoksidnog aniona koji ima glavnu ulogu u mehanizmu bazne transesterifikacije. Padom polariteta alkoksidnog aniona pada i njegov afinitet prema esterskoj skupini triglicerida i time se iskorištenje reakcije smanjuje.Over the past few decades, science has devoted itself more intensively to the development of biofuels with the aim of reducing environmental pollution caused by the burning of fossil fuels. Likewise, the increase in the number of the world's population, rapid industrialization, urbanization, are just some of the factors that cause the growing demand for energy and thus encourage the ever-increasing use of fossil fuels. As fossil fuels are non-renewable sources of energy, researches aimed for fuel that would come exclusively from renewable sources. Biodiesel proved to be a good alternative due to its environmentally friendly nature. It is obtained by catalytic transesterification - the reaction of feedstocks (vegetable oils and animal fats) with an alcohol in the presence of a catalyst. An integral part of fats and oils are triglycerides - esters of glycerol and fatty acids that participate in the transesterification reaction with an alcohol. Therefore, fatty acid alkyl esters (biodiesel) and also alcohol glycerol as a by-product are produced. In this work, biodiesel was synthesized by base – catalyzed transesterification from palm oil as the main feedstock and selected straight-chain alcohols: 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, in the presence of a base catalyst - potassium hydroxide (KOH), since the application properties of biodiesel depend on the structure of the reactants used in the synthesis. The effects of certain parameters on the synthesis reaction were monitored: reaction time (5, 15, 60 minutes), temperature
(60 °C), molar ratio of alcohol and oil (5:1 and 10:1) and mass fraction of catalyst
(1 wt.% KOH and 3 wt.% KOH). In addition to the influence of the mentioned parameters, the influence of the molecular weight of alcohol on the reaction conversion was investigated, as well. With regard to the mentioned alcohols in the biodiesel synthesis reaction, fatty acid propyl, butyl, pentyl, hexyl and octyl esters were produced. The obtained results show that the reaction time has very little or no influence on the reaction conversion. Increasing the mass fraction of the catalyst and the molar ratio of alcohol to oil generally leads to a higher reaction conversion. As the molecular weight of the alcohol increases, the polarity of the alcohol decreases, and ultimately of the alkoxide anion, which plays a major role in the base transesterification mechanism. As the polarity of the alkoxide anion decreases, its affinity towards the ester group of triglycerides also decreases, and thus the conversion of the reaction decreases
Characterization methods for in situ forming hydrogels applied in extended release drug delivery systems
No full textHidrogelovi su hidrofilne, trodimenzionalne polimerne mreže koje mogu apsorbirati velike količine vode ili bioloških tekućina. Zbog visokog sadržaja vode i fizikalno-kemijske sličnosti s izvanstaničnim matriksom, ovi materijali posjeduju svojstva poput bubrenja i odlikuju se izrazitom biokompatibilnošću. U ovom radu, fokus je na poli(laktid-ko-glikolid) (PLGA) polimerima, koji su biorazgradivi i biokompatibilni kopolimeri mliječne i glikolne kiseline, široko prihvaćeni u farmaceutskim i medicinskim proizvodima. PLGA hidrogelovi su jedni od kandidata za primjenu u sustavima za dostavu lijeka s produljenim oslobađanjem u farmaceutskoj industriji. Cilj ovog završnog rada bio je istražiti metode karakterizacije in situ formiranih hidrogelova na osnovi PLGA polimera. Eksperimentalni dio obuhvaća pripravu hidrogelova koristeći polimerne otopine PLGA kopolimera s različitim molnim omjerom laktida (LA) i glikolida (GA) (LA:GA = 85:15 i 50:50) koristeći dimetil sulfoksid (DMSO) i N-metil pirolidon (NMP) kao biokompatibilna otapala u vodenom mediju (fosfatnom puferu). Provedena je karakterizacija formiranih hidrogelova kroz vrijeme gravimetrijskim testom praćenja promjene mase (bubrenje i fizikalna stabilnost), kinetike izlaska otapala tekućinskom kromatografijom visoke djelotvornosti (HPLC), promjene molekulskih masa polimera uslijed hidrolitičke razgradnje gel permeacijskom kromatografijom (GPC metodom) te morfološka ispitivanja pretražnim elektronskim mikroskopom (ESEM). Iz rezultata provedenih mjerenja vidljivo je kontinuirano smanjenje mase formiranih hidrogelova tijekom 14 dana s najvećim padom u prva 24 sata. Gravimetrijski je pokazano da se polimerima s manjim udjelom laktida masa brže smanjuje u odnosu na polimere s većim LA:GA omjerom. HPLC analiza potvrdila je izlazak DMSO otapala iz hidrogelova unutar prva 4 sata. GPC analiza pokazala je kemijsku razgradnju PLGA polimera kroz vrijeme, pri čemu se PLGA polimer s LA:GA omjerom 50:50 brže razgrađivao u odnosu na PLGA polimer s 85:15 omjerom. ESEM ispitivanja ukazala su na neke morfološke razlike između formiranih PLGA hidrogelova s obzirom na sastav polimera i vrstu otapala.Hydrogels are hydrophilic, three-dimensional polymer networks that can absorb large amounts of water or biological fluids. Due to their high water content and physicochemical similarity to the extracellular matrix, these materials possess properties such as swelling and are characterized by excellent biocompatibility. In this paper, the focus is on poly(lactide-co-glycolide) (PLGA) polymers, which are biodegradable and biocompatible copolymers of lactic and glycolic acids, widely accepted in pharmaceutical and medical products. PLGA hydrogels are one of the candidates for application in sustained-release drug delivery systems in the pharmaceutical industry. The aim of this thesis was to investigate methods for the characterization of in situ formed hydrogels based on PLGA polymers. The experimental part includes the preparation of hydrogels using polymer solutions of PLGA copolymers with different molar ratios of lactide (LA) and glycolide (GA) (LA:GA = 85:15 and 50:50) using dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP) as biocompatible solvents in an aqueous medium (phosphate buffer). The formed hydrogels were characterized over time by gravimetric tests monitoring mass changes (swelling and physical stability), solvent release kinetics by high-performance liquid chromatography (HPLC), changes in polymer molecular weights due to hydrolytic degradation by gel permeation chromatography (GPC), and morphological examinations by scanning electron microscopy (ESEM). The results of the measurements showed a continuous decrease in the mass of the formed hydrogels over 14 days, with the largest decrease in the first 24 hours. Gravimetrically, it was shown that the polymer composition (LA:GA ratio) has a greater influence on the mass reduction than the type of solvent (DMSO and NMP). HPLC analysis confirmed the release of DMSO solvent from the hydrogels within the first 4 hours. GPC analysis showed chemical degradation of PLGA polymers over time, with the PLGA polymer with a LA:GA ratio of 50:50 degrading faster than the PLGA polymer with a ratio of 85:15. ESEM examinations indicated some morphological differences between the formed PLGA hydrogels with respect to on the polymer composition and the type of solvent
Influence of aging on the removal of poly(ethylene terephtalate) microplastics with ferrate (VI)
No full textPlastiku karakterizira visoka kemijska i fizička stabilnost, trajnost i niski troškovi proizvodnje. Zbog tih karakteristika postala je široko korištena u industriji i svakodnevnom životu. Međutim, masovna proizvodnja plastike i loše gospodarenje otpadom rezultirali su njenom sveprisutnošću u okolišu što doprinosi ekološkom problemu mikroplastike. Mikroplastika u okolišu nastaje kroz kemijsku, fizičku i biološku degradaciju, a njezina glavna obilježja uključuju visoku kemijsku stabilnost, sposobnost daljnje fragmentacije u nanoplastiku, te sposobnost adsorpcije drugih onečišćujućih tvari. Zbog potencijala za bioakumulaciju također predstavlja ozbiljan rizik za ekosustave i ljudsko zdravlje. Jedan od glavnih izvora mikroplastike u okolišu su vodeni tokovi koji su prošli sustave pročišćavanja jer se mikroplastika teško uklanja standardnim metodama pročišćavanja. Međutim, istraživanja o učinkovitosti uklanjanja mikroplastike još su u ranoj fazi zbog nemogućnosti pronalaska preciznih metoda kvantifikacije mikroplastike u okolišnim uzorcima. Ferati(VI) poznati su po svojoj multifunkcionalnosti, osobito u pročišćavanju onečišćujućih tvari, gdje zahvaljujući snažnim oksidacijskim svojstvima učinkovito djeluju na širok spektar organskih i anorganskih onečišćujućih tvari, uključujući i mikroplastiku. Poli(etilen-tereftalat) (PET) jedan je od najrasprostranjenijih plastičnih materijala, te je zbog svoje dugovječnosti i otpornosti na razgradnju jedan od glavnih tipova polimera prisutnih u okolišu u obliku mikroplastike. U ovom radu ispitana je mogućnost uklanjanja termički starene i nestarene PET mikroplastike procesom koagulacije feratima(VI) iz vodene otopine u različitim uvjetima pH. Masa istaložene mikroplastike određena je mjerenjem sadržaja organskog ugljika u filtratima uzoraka. Ferati(VI) pokazali su se donekle primjenjivim za uklanjanje mikroplastike, međutim potrebno je ispitati učinkovitost uklanjanja pri istim koncentracijama ali manjim obrocima višekratno.Plastic is characterized by high chemical and physical stability, durability, and low production costs. Due to these properties, it has become widely used in industry and daily life. However, mass production of plastic and poor waste management have led to its ubiquity in the environment, contributing to the ecological problem of microplastics. Microplastics in the environment are formed through chemical, physical, and biological degradation, and their main characteristics include high chemical stability, the ability to further fragment into nanoplastics, and the ability to adsorb other pollutants. Due to their potential for bioaccumulation, microplastics also pose a serious risk to ecosystems and human health. One of the main sources of microplastics in the environment are water bodies that have passed through treatment systems, as microplastics are difficult to remove using standard purification methods. However, research on the effectiveness of microplastic removal is still in its early stages due to the lack of precise methods for quantifying microplastics in environmental samples. Ferrates(VI) are known for their multifunctionality, especially in the treatment of pollutants, where thanks to their strong oxidative properties, they effectively act on a wide range of organic and inorganic contaminants, including microplastics. Polyethylene terephthalate (PET) is one of the most widespread plastic materials, and due to its longevity and resistance to degradation, it is one of the main types of polymers present in the environment in the form of microplastics. This study examines the possibility of removing thermally aged and pristine PET microplastics through a coagulation process with ferrates from aqueous solutions under different pH conditions. The mass of precipitated microplastics was determined by measuring the organic carbon content in the filtrates of the samples. Ferrates(VI) have shown to be somewhat effective in removing microplastics; however, it is necessary to investigate the removal efficiency at the same concentrations but with smaller, repeated doses
Chemical oxidative polymerization of aniline monomer in the presence of ZnO nanoparticles
No full textNanokompozit polianilin/cinkov oksid (PANI/ZnO) sintetiziran je in situ kemijsko oksidativnom polimerizacijom monomera anilina (ANI) u prisustvu nanočestica cinkovog oksida (ZnO). U radu su istraženi optimalni uvjeti sinteze koja je provedena u vodenoj otopini organskog otapala dietilen glikola (DEG) uz dodatak 2,5 mL, 5,0 mL te 10,0 mL DEG-a te pri različitim vremenima polimerizacije: 15 min, 30 min, 45 min, 60 min. Karakterizacija sintetiziranih nanokompozita provedena je infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), difuznom refleksijskom spektroskopijom (DRS), rendgenskom difrakcijskom analizom (XRD), pretražnom elektronskom mikroskopijom (SEM) te određivanjem elektrovodljivosti. Na temelju rezultata uspješno je provedena sinteza vodljivog PANI/ZnO nanokompozita polimerizacijom anilina u neutralnom mediju uz dodatak DEG-a u uvjetima u kojima je izbjegnuto otapanje nanočestica ZnO. Nadalje, XRD analiza potvrdila je prisutnost nanočestica ZnO u obliku vurcita, dok su FTIR i DRS spektroskopija, kao i elektrovodljivost dokazali postojanje PANI-ja u vodljivom obliku kao zelena emeraldinska sol (PANI-ES). Iz dobivenih rezultata karakterizacije, može se zaključiti da najbolja vodljiva svojstva pokazuju nanokompozitni uzorci PANI/ZnO/5,0 mL DEG – 15 min (κ/S·cm^-1=2,066⋅10^-4) i PANI/ZnO/10,0 mL DEG – 60 min (κ/S·cm^-1=6,227⋅10^-4). Ovaj predstavljeni pristup pokazuje značajan napredak u sprječavanju otapanja nanočestica ZnO osjetljivih na nizak pH tijekom in situ sinteze PANI/ZnO nanokompozita, čime se značajno proširuje područje njegove primjene, pogotovo u fotokatalizi i senzorima.Nanocomposite polyaniline/zinc oxide (PANI/ZnO) was synthesized by in situ chemical oxidative polymerization of aniline monomer (ANI) in the presence of zinc oxide (ZnO) nanoparticles. The paper investigated the optimal conditions of the synthesis, which was carried out in an aqueous solution of the organic solvent diethylene glycol (DEG) with the addition of 2,5 mL, 5,0 mL and 10,0 mL of DEG and at different polymerization times: 15 min, 30 min, 45 min, 60 min. The characterization of the synthesized nanocomposites was carried out by Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and determination of electrical conductivity. Based on the results, a conductive PANI/ZnO nanocomposite was successfully synthesized by polymerization of aniline in a neutral medium with the addition of DEG under conditions in which the dissolution of ZnO nanoparticles was avoided. Furthermore, XRD analysis confirmed the presence of ZnO nanoparticles in the form of wurtzite, while FTIR and DRS spectroscopy, as well as electrical conductivity, proved the existence of PANI in a conductive form as green emeraldine salt (PANI-ES). From the obtained characterization results, it can be concluded that the best conductive properties are shown by nanocomposite samples PANI/ZnO/5,0 mL DEG – 15 min (κ/S·cm^-1=2,066⋅10^-4) and PANI/ZnO/10,0 mL DEG – 60 min (κ/S·cm^-1=6.227⋅10^-4). This presented approach demonstrates significant progress in preventing the dissolution of low pH-sensitive ZnO nanoparticles during the in situ synthesis of PANI/ZnO nanocomposite, thereby significantly expanding its application area, especially in photocatalysis and sensors
Synthesis of polymer surfactant in green organic solvent
No full textProvedena je sinteza polimerne površinski aktivne tvari u zelenom organskom otapalu metilnom esteru masnih kiselina (biodizelu), uz različite masene udjele prijenosnika rasta lanca. Korišteni monomeri podrazumijevaju dimetilaminoetil-metakrilat (DMAEMA), metil-metakrilat (MMA), dodecil-metakrilat (DDMA) i oktadecil-metakrilat (ODMA). Konverzija reakcije određena je pomoću nuklearne magnetske rezonancije, a postignute su vrlo visoke vrijednosti (> 96 %). Kromatografijom isključenja po veličini dobivena je raspodjela molekulske mase koja potvrđuje nastanak sve većeg broja polimernih molekula manje molekulske mase povećanjem masenog udjela prijenosnika rasta lanca. Kinematičke viskoznosti polimernih otopina i čistog biodizela dobivenog iz uljane repice, izmjerene putem viskozimetra, ukazuju na to kako dodatak sintetiziranih polimernih površinski aktivnih tvari u čisti biodizel dovodi do porasta u njihovim vrijednostima što je korisno za poboljšanje mazivosti. Toplinska svojstva otopina polimera u zelenom organskom otapalu, karakterizirana su pomoću razlikovne pretražne kalorimetrije. Utvrđeno je kako povećanje masenog udjela prijenosnika rasta lanca i smanjenje molekulske mase polimera uzrokuje povišenje temperature pri kojoj počinje kristalizacija. Vrijednosti niskotemperaturnih svojstava, odnosno tecišta i maglišta, imala su gotovo nepromjenjive vrijednosti, unatoč promjeni masenog udjela polimera i molekulske mase polimera. Iznosi faktora trenja, određeni korištenjem reometra, pokazuju prvotni nagli pad vrijednosti pri niskim brzinama klizanja, potom nagli rast povećanjem brzine klizanja i naposljetku oscilirajuće vrijednosti.Synthesis of a polymeric surfactant was conducted in a green organic solvent of methyl ester fatty acids, with various mass fractions of chain transfer agents. Used monomers include dimethylaminoethyl methacrylate (DMAEMA), methyl methacrylate (MMA), dodecyl methacrylate (DDMA) and octadecyl methacrylate (ODMA). Conversion of the reaction was determined by using nuclear magnetic resonance spectroscopy, obtaining extremely high values (> 96 %). Size exclusion chromatography revealed the molecular weight distribution, confirming the formation of an increasing number of polymer molecules with lower molecular weights as the mass fraction of the chain transfer agent was increased. The kinematic viscosities of polymer solutions and pure biodiesel derived from rapeseed, measured using a viscometer, indicate that the addition of synthesized polymeric surfactants to pure biodiesel leads to an increase in their values, which is beneficial for improving lubricity. Thermal properties of polymer solutions in green organic solvent were characterized by the usage of differential scanning calorimetry. It was found that an increase in the mass fraction of the chain transfer agent and a decrease in the molecular weight of the polymer lead to a rise in the temperature at which crystallization begins. The values of low-temperature properties, namely the pour and cloud points, remained nearly unchanged despite variations in the mass fraction of polymers and molecular weight of polymers. The coefficients of friction, determined by using a rheometer, show an initial sharp decrease in values at low sliding speeds that are followed by a sharp increase with increasing sliding speed and finally values that oscillate
Razgradnja antivirusnih lijekova Ribavirina i Emtricitabina Fentonovom oksidacijom
No full textAlong with all the benefits modern medicine has brought, they have also brought issues pertaining to their disposal. Removing medical pollutants from wastewater protects humans as well as the environment. Fenton oxidation is a quick and relatively inexpensive option to oxidize pollutants in wastewater. This thesis investigates the best conditions for Fenton oxidation to decompose two common antiviral medications: ribavirin and emtricitabine.
The tested conditions were reactant concentrations and pH of the reaction. Fenton oxidation requires an iron (II) ion to hydroxyl radicals from hydrogen peroxide that then oxidize the antivirals. Iron (II) concentrations were tested against concentration of hydrogen peroxide in three concentration levels. Each experiment was conducted at three pH levels: 3, 4, and 5. High-performance liquid chromatography was employed to analyze the results.
Response surface modelling was employed to determine the relationship between reactant and pollutant concentrations and the significance of those results were determined by ANOVA. The ribavirin decomposition was plagued by side reactions that reduced the available radical to decompose the medication, resulting in low decomposition but significant results. Emtricitabine decomposition fared better, resulting in complete and near-complete decomposition in one minute with significant results.Uz sve prednosti koje je donijela suvremena medicina, došli su i problemi kod njihova zbrinjavanja i uklanjanja. Uklanjanje medicinskih onečišćujuća tvar iz otpadnih voda štiti ljude kao i okoliš. Fenton oksidacija je brza i relativno jeftina opcija za oksidaciju zagađivača u otpadnoj vodi. Ovaj rad istražuje najbolje uvjete za Fentonovu oksidaciju za razgradnju dva uobičajena antivirusna lijeka: ribavirin i emtricitabin. Uvjeti u ispitivanju bili su koncentracije reaktanata i pH reakcije. Fentonova oksidacija zahtijeva ion željeza (II) za razgradnju vodikovog peroksida u hidroksilne radijale koji zatim oksidiraju antivirusne lijekove. Ispitane su tri koncentracije iona željeza (II) u odnosu na tri koncentracije vodikovog peroksida.
Svaki eksperiment je proveden na tri razine pH: 3, 4 i 5. Za analizu rezultata korištena je tekućinska kromatografija visoke učinkovitosti. Modeliranje površine odgovora korišteno je za određivanje odnosa između koncentracija reaktanata, a značajnost tih rezultata određena je ANOVA. Razgradnja ribavirina bila je praćena nuspojavama koje su smanjile raspoloživi radikal za razgradnju lijeka, što je rezultiralo slabom razgradnjom, ali značajnim rezultatima. Razgradnja emtricitabina bila je bolja, što je rezultiralo potpunom i gotovo potpunom razgradnjom u jednoj minuti sa značajnim rezultatima