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Ultrasonic synthesis of inorganic oxides
No full textPosljednjih nekoliko desetljeća povećala se zainteresiranost istraživanja u području sinteze i primjene nanočestica . Razlog tomu je mala veličina čestica i njihova velika reaktivnost zbog velike specifične površine. Ultrazvučna sinteza je jedna od načina sinteze nanočestica pri čemu se koriste ultrazvučni valovi te se procesom kavitacije stvaraju visoka temperatura i tlak. U ovom radu opisana je i korištena ultrazvučna sinteza anorganskih oksida iz smjese vodenih otopina L-histidina, niklovog(II) nitrata heksahidrata i natrijevog hidroksida. U literaturnom dijelu opisani su pojmovi zvuka, ultrazvuka, kavitacije i optičkog energijskog procijepa. Metode koje su korištene za analizu spojeva dobivenih ovom sintezom su UV/VIS i infracrvena (IR) spektroskopija te termogravimetrijska analiza (TGA). U eksperimentalnom dijelu prikazan je postupak ultrazvučne sinteze i analiza rezultata. Utvrđeno je nastajanje NiO i Ni(OH)2. Taucovom metodom izračunata je energija indirektnog i direktnog optičkog energijskog procijepa koji ukazuje da je nastali anorganski oksid poluvodič.In the last few decades, the interest in research in the area of nanoparticle synthesis and application has increased. The reason for this is the small size of the particles and their high reactivity due to their large surface area. Ultrasonic synthesis is one of the ways of nanoparticle synthesis, where ultrasonic waves are used, and high temperature and pressure are created through the cavitation process. In this paper, the ultrasonic synthesis of inorganic oxides was described and used from a mixture of aqueous solutions of L-histidine, nickel(II) nitrate hexahydrate, and sodium hydroxide. The literature section describes the concepts of sound, ultrasound, cavitation and optical band gap. The methods used to analyze the compounds obtained from the synthesis are UV/VIS and infrared (IR) spectroscopy and thermogravimetric analysis (TGA). In the experimental part, the ultrasonic synthesis procedure and the analysis of the results are presented. The formation of NiO and Ni(OH)2 was determined. Using the Tauc method, the values of indirect and direct band gaps were calculated, indicating that the formed inorganic oxide is a semiconductor
Synthesis of lanthanide metal-organic frameworks and their derivates
No full textSolvotermalnom sintezom u smjesi otapala N, N - dimetilformamida (DMF) i vode sintetizirane su metalo-organske mreže (MOF) na osnovi lantanoida, itrija i cirkonija s jantarnom kiselinom. Cilj ovog istraživanja je dobiti jednofazne MOF-ove s jednim ili više metala u strukturi kako bi nastali visokoentropijski spojevi te ispitati koji derivati nastaju termičkom razgradnjom istih. Pripremljeni spojevi su okarakterizirani rentgenskom difrakcijom u prahu (PXRD), termogravimetrijskom analizom s razlikovnom pretražnom kalorimetrijom (TGA/DSC), pretražnom elektronskom mikroskopijom s energijski razlučujućom rentgenskom spektroskopijom (SEM-EDS), analizirana im je specifična površina i veličina pora pomoću analizatora specifične površine i veličine pora, te je odabranim spojevima ispitana katalitička aktivnost na fotokatalitičku hidrogenaciju CO2.Metal-organic networks (MOFs) based on lanthanides, yttrium and zirconium with succinic acid were synthesized by solvothermal synthesis in the solvent mixture of N, N - dimethylformamide (DMF) and water. The goal of this research is to synthesize single-phase MOFs with one or more metals in the structure in order to create high-entropy compounds and to investigate the type of derivates that are obtained by their thermal degradation. Obtained compounds were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis with differential scanning calorimetry (TGA/DSC), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), while their specific surface areas and pore sizes were investigated using surface area and pore size analyzer, and the catalytic activity of selected compounds was examined towards the photocatalytic hydrogenation of CO2
Green synthesis of nanoparticles using the fungi extracts
No full textU ovome radu istražena je mogućnost zelene sinteze nanočestica srebra iz vodenog ekstrakta gljive Irpex lacteus. Sintetizirane nanočestice srebra okarakterizirane su metodama UV-Vis i FT- IR spektroskopije. Procijenjena je i sposobnost razlaganja boje vodene otopine berlinskog plavila. Rezultati UV-Vis spektroskopije pokazali su da je maksimum apsorbancije prisutan na 418 nm. Rezultati FT- IR spektroskopije ukazali su na biomolekule odgovorne za sintezu nanočestica srebra. Sintetizirane nanočestice srebra pokazale su dobru sposobnost razlaganja berlinskog plavila. Do potpune razgradnje došlo je nakon 24 sata. Vodeni ekstrakt gljive Irpex lacteus pokazao se kao iznimno dobar reducirajući i stabilizirajući agens.This study explored the potential for green synthesis of silver nanoparticles from the aqueous extract of the fungus Irpex lacteus. The synthesized silver nanoparticles were characterized using UV-Vis and FT-IR spectroscopy. Additionally, the ability to degrade the color of an aqueous solution of methylene blue was evaluated. The results of UV-Vis spectroscopy indicated a maximum absorption peak at 418 nm. The results of FT-IR analysis indicated the possible biomolecules responsible for capping the silver nanoparticles. The synthesized silver nanoparticles exhibited excellent methylene blue degradation capability, with complete degradation occurring after 24 hours. The aqueous extract of Irpex lacteus proved to be an exceptionally effective reducing and stabilizing agent
Environment effects of freons
No full textFreoni, odnosno klorofluorougljici, su spojevi koji su zbog svojih karakteristika imali veliku primjenu u širokom spektru djelatnosti. Iako značajno ne utječu na čovjekovo zdravlje, pokazalo se da su iznimno opasni za ozonski omotač, a time i za organizme na Zemlji. Zbog stvaranja ozonskih rupa, freoni se smatraju indirektnim uzročnikom uništavanja mnogih vrsta organizama, bilo životinjskih bilo biljnih ili patogenih. Svojim djelovanjem također ne utječe direktno na njihovo izumiranje, već na uništavanje njihova staništa ili smanjenje hrane čime onemogućavaju njihovo daljnje obitavanje na nekom prostoru što uvelike utječe na cjelokupnu biosferu. Tako povišenjem temperature dolazi do topljenja ledenjaka na kojem žive polarni medvjedi ili se povećanjem količine UV zračenja uništava fitoplankton. Iako je najprije rečeno kako ovakvi spojevi nisu štetni za čovjeka, potvrđeni su neki slučajevi kod kojih se javio problem sa srcem pri većoj izloženosti ovim spojevima. S obzirom na cjelokupnu štetnost ovih spojeva, doneseni su mnogi zakoni i regulative kojima bi se smanjila njihova koncentracija u atmosferi i na taj način očuvao planet i njegov cjelokupni okoliš.Freons, more precisely chlorofluorocarbons, are compounds which, due to their characteristics, have been widely used. Even though they do not significantly affect human health, it has been shown that they are extremely dangerous for the ozone layer, but also for other organisms on Earth. By creating ozone holes, freons are considered to be an indirect cause of the destruction of many types of organisms, whether animal, plant or pathogenic. By their action, they do not directly affect their extinction, but by destroying their habitat or reducing food, freons make it impossible for them to continue living in a certain area, which greatly affects the entire biosphere. A temperature increase leads to the glaciers melting on which polar bears live and increase of UV radiation destroys phytoplankton. Although it was initially said that such compounds are not harmful to humans, some cases of heart problems have been confirmed due to greater exposure to these compounds. Considering the overall harmfulness of these compounds, many laws and regulations were passed to reduce their concentration in the atmosphere and preserve the planet and its entire environment
Green synthesis of nanoparticles using the extracts of Mistletoe (Viscum album L.)
No full textBiljni su ekstrakti bogat izvor biomolekula koje su korisne ne samo kao antioksidansi, lijekovi ili dodatci prehrani već i kao složeni reagensi za sintezu metalnih nanočestica. U ovom radu provedena je zelena sinteza nanočestica srebra iz metanolnog ekstrakta biljke imele (Viscum album L.) i vodene otopine AgNO3. Sintetizirane nanočestice okarakterizirane su UV-VIS spektrometrijom, FT-IR analizom i rendgenskom difrakcijom na prahu. Katalitička aktivnost dobivenih nanočestica procijenjena je pomoću metilenskog modrila. Utvrđeno je da do potpune razgradnje boje došlo nakon 24 sata. Rezultati karakterizacije sintetiziranih nanočestica ukazuju na uspješnu sintezu nanočestica iz ekstrakta Viscum album s UV-VIS apsorpcijskim maksimumom na 441 nm. Rezultat PXRD analize pokazuje da je prosječna veličina kristalita 21 nm.Plant extracts are a rich source of biomolecules that are valuable not only as antioxidants, medicines or dietary supplements but also as complex reagents for the synthesis of metal nanoparticles. In this study, green synthesis of silver nanoparticles was performed using methanolic extract of the mistletoe plant (Viscum album L.) and an aqueous solution of AgNO3. The synthesized nanoparticles were characterized using UV-VIS spectrometry, FT-IR analysis, and powder X-ray diffraction (PXRD). The catalytic activity of the obtained nanoparticles was assessed using methylene blue. It was found that complete color degradation occurred after 24 hours. The results indicate the successful synthesis of nanoparticles from Viscum album extract with a UV-VIS absorption maximum at 441 nm. The PXRD analysis result shows that the average crystallite size is 21 nm
The synthesis of functionalized multi-walled carbon nanotubes
No full textUgljikove nanocjevčice su relativno novootkrivena alotropska modifikacija ugljika s mnogim izvrsnim svojstvima poput fleksibilnosti, sposobnosti oporavka od ekstremnog uvijanja, električne i toplinske vodljivosti te sposobnosti emisije elektrona. Fokus mnogih znanstvenih istraživanja novoga doba baziran je na ispitivanje i poboljšavanje svojstava ugljikovih nanocjevčica zbog raznih područja u kojima imaju potencijalne primjene. Ograničavajući faktor za ispunjavanje potencijala predstavlja slaba topljivost ugljikovih nanocjevčica u većini otapala, pa se daljnja istraživanja fokusiraju na njihovu modifikaciju na način koji će što manje utjecati na već postojeća svojstva, ali otvoriti vrata novim primjenama poboljšavajući topljivost. Jedan od načina modifikacije u svrhu poboljšanja topljivosti je funkcionalizacija koja može biti kovalentna i nekovalentna. U ovome je radu opisana sinteza MWCNT-OSO3H iz komercijalno dostupnih, već kovalentno funkcionaliziranih MWCNT-OH i klorsulfonske kiseline, uz tetrahidrofuran kao otapalo.Carbon nanotubes are a relatively recently discovered allotropic modification of carbon with many excellent properties, such as flexibility, the ability to recover from extreme twisting, electrical and thermal conductivity, and the ability to emit an electric field. The focus of many scientific researches of the new era is based on testing and improving the properties of carbon nanotubes due to the various areas in which they have potential applications. The limiting factor for fulfilling the potential is the poor solubility of carbon nanotubes in most solvents, so further research focuses on their modification in a way that will affect the existing properties as little as possible, but open the door to new applications by improving solubility. One way of modifying to improve solubility is functionalization, which can be covalent or non-covalent. This paper describes the synthesis of MWCNT-OSO3H from commercially available, already covalently functionalized MWCNT-OH and chlorosulfonic acid, with tetrahydrofuran as a solvent
Blistering warfare agents
No full textKožni bojni otrovi, kao skupina smrtonosnih kemijskih bojnih otrova, korišteni su tijekom povijesti prouzročivši oko 2 milijuna žrtava samo za vrijeme Prvoga svjetskog rata. Stoga je razumijevanje ovih sredstava i njihovog načina djelovanja ključno za razvoj učinkovite dekontaminacije i terapijskih strategija. Kategorizirani su na temelju njihovih kemijskih i bioloških interakcija. Poznato je da ti spojevi uvelike uzrokuju iritaciju i stvaranje mjehurića na koži i sluznicama (uglavnom pluća) zajedno s alkilacijom kontaminirane DNK. Zbog visoke toksičnosti i ograničene uporabe, provedeno je vrlo malo istraživanja. U ovom radu opisuju se kožni bojni otrovi te informacije o njihovim fizičkim, kemijskim i biološkim aspektima. Također se opisuju sinteze otrova te njihovi toksikološki učinci na čovjeka i okoliš.Warfare blister agents, as a group of lethal chemical warfare agents, have been used throughout history and caused approximately 2 million casualties just during the First World War. Therefore, understanding of these agents and their mode of action is essential for the development of effective decontamination and therapeutic strategies. They are categorized based on their chemical and biological interactions. These compounds are known to greatly cause irritation and blisters on the skin and mucous membranes (mainly lungs) followed by alkylation of contaminated DNA. Research has been limited due to their high toxicity and limited use. In this paper, blistering warfare agents and information on their chemical, biological and physical aspects are described. Syntheses and their toxicological effects on humans and the environment are also described
Walnut fruit extract based green synthesis of silver nanoparticles
No full textNanočestice se mogu koristiti u medicini, tekstilnoj industriji, elektronici i brojnim drugim područjima korisnima za čovjeka. U njihovoj sintezi se sve više koristi postupak zelene sinteze jer je jeftin i ekološki prihvatljiv. U ovom radu provedena je zelena sinteza nanočestica srebra iz vodenog ekstrakta jednoga od dijelova ploda oraha (pregrade) i vodene otopine AgNO3. Dobivene nanočestice srebra karakterizirane su FT-IR analizom, UV-Vis spektroskopijom te rendgenskom difrakcijom na prahu - PXRD. Dobiveni su rezultati ukazali na uspješnu sintezu nanočestica srebra. Apsorpcijski maksimum nalazio se na približno 420 nm. Veličina sintetiziranih nanočestica izračunata uz pomoć Scherrer-ove formule iznosila je 9 nanometara. Rezultati FT-IR analize ukazali su na biomolekule odgovorne za uspješnu sintezu nanočestica srebra.Nanoparticles can be used in medicine, textile industry, electronic industry and many other fields useful to humans. The green synthesis is becoming more common in the synthesis of silver nanoparticles because it is cheaper and more ecologically acceptable. In this work, green synthesis of silver nanoparticles was conducted using aqueous extract of a part of a walnut fruit (partitions) and silver nitrate - aqueous solution of AgNO3. Synthesized silver nanoparticles were characterized using FT-IR analysis, UV-visible spectrophotometry and powder X-ray diffraction - PXRD. The results show that silver nanoparticles were produced successfully. The absorption maximum occurs at approximately 420 nm. The size of silver nanoparticles is 9 nm, which was determined using Scherrer's equation. The results of FTIR analysis show which biomolecules are responsible for a successful synthesis of nanoparticles
The influence of ultrasound on the extraction of carnosine from real samples
No full textKarnozin je dipeptid koji je građen od dvije aminokiseline β-alanina i ʟ-histidina. Karnozin i njegovi analozi u prirodi su prisutni kod životinja, a postoji veliki raspon koncentracija u ukupnom sadržaju između različitih sisavaca. Ekstrakcija potpomognuta ultrazvukom je metoda jednostavna za korištenje, relativno jeftina, povećava prijenos mase i kinetiku reakcija, te je prikladna za široki spektar otapala i uzoraka. Tekućinska kromatografija ultra visoke djelotvornosti (UPLC) koristi manje čestice u kolonama, ima veću brzinu i kraće vrijeme razdvajanja, veću rezoluciju i veći vršni kapacitet. U radu je ispitivan utjecaj direktnog i indirektnog djelovanja ultrazvuka na ekstrakciju karnozina iz mesa pilećih prsa u odnosu na ekstrakciju koja koristi homogenizator. Za određivanje sadržaja karnozina i anserina korištena je tekućinska kromatografija ultra visoke djelotvornosti. Kod metode koja koristi homogenizator, najmanja RSD vrijednost dobivena je za uzorke kojima je sadržaj karnozina i anserina određen nakon 60 s. Ekstrakcija indirektnim ultrazvukom pokazala je da se produljenjem vremena ekstrakcije povećava sadržaj karnozina i anserina što ukazuje na poboljšanje ekstrakcije. Najbolje rezultate dala je direktna ultrazvučna ekstrakcija kontinuirano 60 s u odnosu na isto vrijeme ekstrakcije prilikom upotrebe homogenizatora. Također je ispitivana razlika između ekstrakcije karnozina i anserina u usitnjenim i neusitnjenim uzorcima. Veći sadržaj karnozina i anserina određen je u neusitnjenim uzorcima što znači da uzorci mesa ne moraju, prije ekstrakcije direktnim ultrazvukom, biti usitnjeni.Carnosine is a dipeptide made of two amino acids β-alanine and ʟ-histidine. Carnosine and its analogues are naturally present in animals, and there is a wide range of concentrations in the total content between different mammals. Ultrasound-assisted extraction method is easy to use, relatively inexpensive, increases mass transfer and reaction kinetics, and is suitable for a wide range of solvents and samples. Ultra high performance liquid chromatography (UPLC) uses smaller particles in the columns, has faster speed and shorter separation time, higher resolution and higher peak capacity. In this thesis the influence of direct and indirect ultrasound on the extraction of carnosine from chicken breast meat was investigated and obtained results were compared with the results obtained by extraction with homogenizator. Ultra high performance liquid chromatography was used to determine the carnosine and anserine content. In the method that uses a homogenizer, the lowest RSD value was obtained for samples whose carnosine and anserine content was determined after 60 s. Extraction using indirect ultrasound showed that extending the extraction time increases the content of carnosine and anserine, which indicates an improvement in extraction. The best results were obtained by direct ultrasonic extraction continuously for 60 s compared to the same time of using the method with a homogenizer. The difference between the extraction of carnosine and anserine in the minced meat samples and samples where meat was not minced was also investigated. The higher content of carnosine and anserine was determined in samples where meat was not minced, which means that the meat samples do not have to be minced before extraction by direct ultrasound
Heavy metal(loid) concentrations in tissues of wild boar from region of Papuk Nature park (eastern Croatia)
No full textU ovome radu analizirane su koncentracije metala i metaloida u tkivima divljih svinja s područja Parka prirode Papuk, smještenog u istočnoj Hrvatskoj. Uspoređene su koncentracije Cd, Pb, As i Hg u tkivima divljih svinja s područja Papuka s koncentracijama iz drugih dijelova Hrvatske i nekih zemalja EU, a metodom analize glavnih komponenata istražene su međusobne korelacije između koncentracija i mjesta uzorkovanja. Koncentracije Cd, Pb i Hg u uzorcima bubrega, jetara i mišića s područja Papuka nisu se značajno razlikovale od onih u drugim dijelovima Hrvatske. Koncentracije As u uzorcima bubrega (0,09 mg kg-1), jetara (0,08 mg kg-1) i mišića (0,07 mg kg-1) s područja Papuka bile su više u odnosu na ostale dijelove Hrvatske (0,015 - 0,02 mg kg-1). Koncentracije Cd i Pb bile su veće u bubrezima, jetrima i mišićima divljih svinja koje su ulovljene na područjima izvan Hrvatske, odnosno u drugim zemljama EU. Rezultat primijenjene metode analize glavnih komponenata ukazao je na povišene koncentracije arsena u tkivima divljih svinja ulovljenih na zapadnom dijelu Papuka i povišene koncentracije Cd i Hg u tkivima životinja ulovljenih na južnom dijelu Papuka.In this study, concentrations of metals and metalloids in tissues of wild boars from the Papuk Nature Park area, located in eastern Croatia, were analyzed. Concentrations of Cd, Pb, As, and Hg in wild boar tissues from the Papuk area were compared with concentrations from other parts of Croatia and some EU countries. Using the principal component analysis method, correlations between concentrations and sampling locations were explored. Concentrations of Cd, Pb, and Hg in kidney, liver, and muscle samples from the Papuk area did not significantly differ from those in other parts of Croatia. Concentrations of As in kidney samples (0.09 mg kg-1), liver samples (0.08 mg kg-1), and muscle samples (0.07 mg kg-1) from the Papuk area were higher compared to other parts of Croatia (0.015 - 0.02 mg kg-1). Concentrations of Cd and Pb were higher in kidneys, livers, and muscles of wild boars caught outside of Croatia, i.e., in other EU countries. The results of the applied principal component analysis method indicated elevated concentrations of arsenic in wild boar tissues caught in the western part of Papuk and elevated concentrations of Cd and Hg in animal tissues caught in the southern part of Papuk