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The presence of microplastics in waste sludges
No full textOnečišćenje mikroplastikom (MP) postaje sve veći problem na globalnoj razini. Čestice MP toksična su onečišćivala koja svojom prisutnošću i aglomeriranjem znatno utječu na ekosustav tla, organizme i naposlijetku na zdravlje ljudi. Njihova mogućnost interakcije s drugim onečišćujućim tvarima, sklonost da ih živi organizmi progutaju i dugovječnost predstavlja ozbiljnu prijetnju okolišu. Navedene čestice ulaze u okoliš putem pročišćenih otpadnih voda ili otpadnih muljeva iz uređaja za pročišćavanje. Svrha ovog rada je dati pregled o prisutnosti MP u otpadnim muljevima i njihovog utjecaja na okoliš. Otpadni muljevi su nusprodukti uređaja za pročišćavanje otpadnih voda. Njihova važnost se povećala kako su se počeli promatrati kao izvor energije, a ne kao otpadni proizvodi. Obzirom da uz hranjive tvari sadržavaju i određenu količinu onečišćujućih tvari poput MP, otpadni muljevi djeluju kao ulaz različitih onečišćivala u kopnene i vodene sredine. Ovim radom ukazat će se alternativne metode za održivo upravljanje otpadnim muljevima koje su u skladu sa provođenjem kružnog gospodarstva.Microplastic (MP) pollution is becoming a growing problem globally. MP particles are considered toxic pollutants, which, by their presence and agglomeration, significantly affect the soil ecosystem, organisms and ultimately human health. Their ability to interact with other pollutants, their tendency to be ingested by living organisms and their longevity pose a serious threat to the environment. These particles enter the environment via purified wastewater or waste sludge from treatment plants. The purpose of this paper is to provide an overview of the presence of MP in waste sludge and their impact on the environment. Waste sludge is a byproduct of wastewater treatment plants. Their importance increased as they began to be seen as a source of energy rather than waste products. Given that, in addition to nutrients, they also contain a certain amount of pollutants such as MP, waste sludge acts as an entrance of various pollutants into land and water environments. This work will show alternative methods for the sustainable management of waste sludge that are in accordance with the implementation of a circular economy
Researches in the field of AOP degradation of antiviral substances
No full textAntivirotici su farmaceutici koji se koriste za borbu protiv virusnih oboljenja. Za razliku od cjepiva koja se koriste preventivno za istu svrhu, antivirotici se primjenjuju nakon što je virus već ušao u organizam. Nažalost, antivirotici, kao i ostali farmaceutici, uslijed korištenja djelom završavaju u okolišu gdje mogu uzrokovati neželjene efekte. Antivirotici su po sastavu organske molekule koje često sadržavaju aromatske prstene što ih čini slabo reaktivnima i otpornima na konvencionalne načine obrade otpadnih voda. Jedan od mogućih načina uklanjanja antivirotika su napredni oksidacijski procesi (engl. advanced oxidation process; AOP). AOP-i podrazumijevaju skup procesa koji su integralni dio kemijske obrade najčešće organskih, a ponekad i anorganskih tvari u vodama i otpadnim vodama uz pomoć radikala koji se ponašaju kao jaka oksidacijska sredstva i pretvaraju organsku tvar u CO2, H2O i netoksične spojeve. Radikali se najčešće stvaraju uz primjenu neke vrste katalizatora. Najčešće se primjenjuju fotokemijski, elektrokemijski i sonokemijski procesi ili neka od njihovih kombinacija. AOP-i su u zadnjih nekoliko desetljeća zadobili dosta pažnje znanstvene zajednice radi potencijalne primjene u dezinfekciji, dekolorizaciji i deodorizaciji te najbitnije zbog potencijala da prevodi antropogene i teško biorazgradive organske tvari u forme koje su biorazgradive. Međutim, AOP tretmanom mogu nastati i međuprodukti koji su toksičniji od inicijalnih spojeva. Stoga je svaki AOP tretman poželjno detaljno istražiti. Na uspješnost AOP-a utječu razni faktori poput pH vrijednosti medija, koncentracije i načina uvođenja oksidacijskog sredstva u sustav, brzine reakcije nastajanja radikala, te druge varijable specifične za određenu vrstu AOP-a.Antivirals are pharmaceuticals used to fight against viral diseases. Unlike vaccines that are used preventively for the same purpose, antivirals are applied after the virus has already entered the body. Unfortunately, antivirals, like other pharmaceuticals, end up in the environment as a result of their use, where they can cause unwanted effects. Antivirals are composed of organic molecules that often contain aromatic rings, which makes them weakly reactive and resistant to conventional methods of wastewater treatment. One of the possible ways of removing antivirals is advanced oxidation process (AOP). AOPs include a set of processes that are an integral part of the chemical treatment of mostly organic and sometimes inorganic substances in water and wastewater with the help of radicals that act as strong oxidizing agents and convert organic matter into CO2, H2O and nontoxic compounds. Radicals are most often created with the use of some type of catalyst. Photochemical, electrochemical and sonochemical processes or some of their combinations are most often applied. In the last few decades, AOPs have received a lot of attention from the scientific community due to their potential application in disinfection, decolorization and deodorization, and most importantly because of their potential to convert anthropogenic and difficult-tobiodegradable organic substances into biodegradable forms. However, AOP treatment can also produce intermediate products that are more toxic than the initial compounds. Therefore, it is desirable to investigate each AOP treatment in detail. The success of AOP is influenced by various factors, such as the pH value of the medium, the concentration and method of introduction of the oxidizing agent into the system, the speed of the radical reaction, and other variables specific to a certain type of AOP
Remediation of wastewater polluted with microplastics
No full textSvrha ovog rada je pružiti pregled tehnika i tehnologija koje se trenutno koriste u remedijaciji otpadnih voda onečišćenih mikroplastikom (MP). Mikroplastika, su čestice sitne plastike manje od 5 mm, predstavlja ozbiljan ekološki problem jer može onečišćivati vodne ekosustave i negativno utjecati na živi svijet. U ovom radu dan je pregled biogeokemijskog ciklusa mikroplastike od njenog nastajanja i njenih izvora, metode njene identifikacije i detekcije u otpadnim vodama, tehnike uklanjanja iz otpadnih voda u postrojenjima za obradu otpadnih voda. Istraživanja ukazuju da postrojenja za obradu otpadnih voda imaju važnu ulogu u otpuštanju mikroplastike u okoliš.The purpose of this paper is to provide an overview of techniques and technologies currently used in the remediation of wastewater contaminated with microplastics (MPs). Microplastics are tiny plastic particles smaller than 5 mm, they pose a serious ecological problem as they can pollute aquatic ecosystems and have negative impacts on the environment. This paper presents a comprehensive review of the biogeochemical cycle of microplastics, from their formation and sources, methods of identification and detection in wastewater, removal techniques from wastewater in wastewater treatment plants. Research indicates that wastewater treatment plants play a significant role in the release of microplastics into the environment
Study of specific drug content in tablets
No full textU ovom istraživanju, ispituje se sadržaj specifične djelatne tvari u tabletama. Potrebno je pronaći medij te valnu duljinu snimanja pri kojima će se uspješno spektrofotometrijski odrediti sadržaj specifične djelatne tvari. Analizom rezultata detektirani su uvjeti potrebni za uspješnu karakterizaciju. Određivan je sadržaj dasatiniba u komercijalno dostupnim tabletama točno poznatog sadržaja. Testirane su tri unaprijed validirane UV/Vis spektroskopske metode. Kao diluenti korišteni su: metanol, 0,1 M HCl i acetonitril. Rezultati pokazuju da je sadržaj djelatne tvari u metanolu i 0,1 M HCl ujednačen te da odgovara propisanom sadržaju. U slučaju primjene acetonitrila sadržaj djelatne tvari je prenizak, a apsorpcijski spektar pokazuje interferencije s prisutnim pomoćnim tvarima. Metanol i HCl su pokazuju se kao diluenti pogodni za UV/Vis spektrofotometrijsko određivanje sadržaja dasatiniba u tabletama.In this research, the content of a particular drug in tablets is studied. There is a need to find an optimum medium and wavelength to which the content of this specific drug will be successfully determined spectrophotometrically. The conditions required for this susccessful characterization were detected by analysing the results. Dasatinib content was detected in commercially available tablets with well-defined drug content. Three pre-validated UV/Vis spectrophotometric methods were tested. Methanol, 0,1 M HCl and acetonitrile were used as diluents. The results showed that the content of the drug in methanol and 0,1 M HCl is uniform and corresponds to the prescribed content. For the case of using acetonitrile, the drug content is too low while absorption spectrum indicates interference with excipients present. Methanol and HCl have been found as diluents suitable for UV/Vis spectrophotometric measurement of dasatinib content in tablets
Vmin method for the dividing wall column design
No full textKolone s razdjelnom stijenkom su toplinski potpuno povezani destilacijski nizevi izvedeni unutar jednog plašta. Za razliku od konvencionalnih kontinuiranih destilacijskih kolona, pomoću KRS se može ostvariti oštra separacija tri ili više proizvoda, uz značajne uštede energije i kapitala. S obzirom da su konstrukcijski složene, njihov proračun je bitno kompleksniji. Stoga su približne metode proračuna, kojima se mogu dobiti skupovi podataka potrebnih za inicijalizaciju detaljnih modela, izuzetno važne. Jedina za sad postojeća približna metoda proračuna je tzv. Vmin metoda. Vmin metoda temelji se na Underwoodovom postupku, a pomoću nje se dobiva grafički prikaz minimalnog protoka pare i protoka destilata za postizanje određenog iscrpka ključnih komponenata, što predstavlja osnovu za detaljni proračun. Tema ovog završnog rada je pregled primjene Vmin metode za približni proračun destilacijskih kolona s razdjelnom stijenkom za tri proizvoda.Dividing wall columns are fully thermally coupled distillation sequences realized within a single shell. Unlike conventional continuous distillation columns, a sharp separation of three or more products can be achieved with the help of KRS, with significant energy and capital savings. Since they are structurally complex, their calculation is much more complex. Therefore, approximate calculation methods, by which datasets required behind the initialization of detailed models can be obtained, are extremely important. The only approximate calculation method existing so far is the so-called Vmin method. The Vmin method is based on the Underwood procedure, and it provides a graphical representation of the minimum steam flow and distillate flow required to achieve a certain exhaustion of key components, which is the basis for a detailed calculation. The topic of this final work is an overview of the application of the Vmin method for the approximate calculation of distillation columns with a dividing wall for three products
Climate goals of COP26 conference
No full textPovećanje potrošnje energije i emisija stakleničkih plinova u posljednjih 250 godina pridonijelo je povećanju globalnih temperatura. Globalni porast temperature u nižim slojevima atmosfere sa svojim brojnim posljedicama često se nazivaju globalnim klimatskim promjenama. Posljedice globalnih klimatskih promjena u posljednjih 50 godina, koje su sve jasnije, potaknule su međunarodnu javnost na brojne aktivnosti usmjerene na zaustavljanje globalnog porasta temperature. Ovaj rad ispituje problematiku emisije stakleničkih plinova, klimatskih promjena i međunarodnih aktivnosti koje se poduzimaju u nastojanju da se spriječe klimatske promjene te njihovu uspješnost.The increase in energy consumption and greenhouse gas emissions over the past 250 years has contributed to an increase in global temperatures. The global increase in temperature in the lower layers of the atmosphere with its numerous consequences is often called global climate change. The consequences of global climate changes in the last 50 years, which are increasingly clear, have encouraged the international public to take numerous actions aimed at stopping the global temperature rise. This paper examines the issue of greenhouse gas emissions, climate change and international activities undertaken in an effort to prevent climate change and their effectiveness
Application of Fenton-like processes in the degradation of microplastics
No full textUpotreba plastike iz godine u godinu sve više raste zbog čega je i sve veća njena prisutnost u okolišu uslijed neadekvatnog zbrinjavanja. Posebnu zabrinutost predstavlja mikroplastika zbog svoje veličine i drugih svojstava te štetnog učinka koje ima na cjelokupni ekosustav. Zbog manjka učinkovitosti dosadašnjih metoda za uklanjanje mikroplastike iz okoliša, razmotrena je primjena naprednih oksidacijskih procesa. To su procesi u kojima dolazi do stvaranja reaktivnih radikala koji su u mogućnosti potpuno ili djelomično razgraditi organske onečišćujuće tvari među kojima je i mikroplastika. U ovome radu ispitana je primjena Fentonu sličnog procesa koji koristi nula valentno željezo kao katalizator za razgradnju mikroplastike polietilena niske gustoće, polipropilena i poli(vinil-klorida). Eksperimenti su provedeni prema potpunom faktorskom planu, a ispitana su 3 numerička faktora: pH vrijednost, omjer Fe0 i MP te omjer Fe0 i H2O2, na tri razine (-1, 0 i 1). Za karakterizaciju mikroplastike koristila se FTIR spektroskopija, a za analizu vodenog medija provedena je TOC analiza. Na temelju dobivenih rezultata, određeni su optimalni uvjeti razgradnje za svaku vrstu plastike. Dobiveni rezultati pokazali su kako ispitani napredni oksidacijski proces nije uzrokovao potpunu mineralizaciju niti jedne mikroplastike. Nakon provedbe Fentonu sličnog procesa, došlo je do minimalne površinske razgradnje mikroplastike polietilena niske gustoće i polipropilena dok je kod mikroplastike poli(vinil-klorida) uočena djelomična razgradnja. Iako nije došlo do potpune razgradnje ispitivanih mikroplastika, zaključeno je da učinkovitost Fentonu sličnog procesa ovisi o svim ispitivanim parametrima te da najveći utjecaj na učinkovitost Fentonu sličnog procesa ima pH vrijednost.The use of plastic is increasing through the years causing its wide presence in the environment due to inadequate disposal. Microplastics present the biggest concern because of its size, other properties and because of the harmful effect they have on the entire ecosystem. Due to the lack of efficiency of the current methods for removing microplastics, the application of advanced oxidation processes was considered. These are processes that lead to the formation of reactive radicals that can completely or partially decompose pollutants, including microplastics. This paper examines the application of Fenton-like process using zero-valent iron for the degradation of microplastics of low-density polyetylene, polypropylene and poly(vinyl-chloride). The experiments were conducted according to full factorial design and 3 numerical factors were observed: the pH value, the ratio of Fe0 and MP, and the ratio of Fe0 and H2O2 at three levels (-1, 0 and 1). FTIR spectroscopy was used to characterize these types of plastics. For the aqueous medium, TOC analysis was performed. Based on the obtained results, the optimal conditions that cause degradation of each type of plastic were determined. The obtained results showed that examined advanced oxidation process did not cause complete mineralization of any type of plastic. After the implementation of the Fenton-like process, there was minimal surface degradation of low-density polyethylene and polypropylene microplastics while partial degradation was observed with poly(vinyl-chloride) microplastics. Although the tested microplastics did not completely decompose, it was concluded that the effectiveness of the Fenton-like process depends on all the tested parameters and that the pH value has the greatest influence on the effectiveness of the Fenton-like process
Synthesis of covalently crosslinked conductive polymer PEDOT-g-PEG
No full textOd svog otkrića elektrovodljivi polimeri privukli su pozornost zbog svojstva otpornosti na koroziju, električne vodljivosti i niske gustoće. Svojstvo električne vodljivosti omogućuje naizmjenični raspored jednostruke i dvostruke veze te uvođenje slobodnog nositelja naboja. Jedan od glavnih predstavnika elektrovodljivih polimera je poli(3,4-etilendioksitiofen) (PEDOT) zbog svoje dobre kemijske stabilnosti, biokompatibilnosti, niskih troškova proizvodnje te električne vodljivosti u rangu poluvodiča. Uvođenjem bočnih grana
poli(etilen-glikola) (PEG) poboljšavaju se istezljivost i savitljivost zbog uspostave nekovalentnog umreženja vodikovim vezama što omogućuje potencijalnu primjenu u polju nosive elektronike. Dodatkom sredstva za umrežavanja moguće je ostvariti potpuno kovalentno umreženje što dodatnu povećava istezljivost, a povećava se i otpornost na kemikalije. Sinteza graft kopolimera provodila se u četiri koraka. U prvom koraku sintetizirao se bromom funkcionalizirani monomer tiofena, ThBr, a u drugom makroinicijator PEDOT-Br. Potom je sintetiziran graft kopolimer PEDOT-g-PEG graftiranjem bočnih lanaca PEG-a na glavni lanac PEDOT-Br radikalskom polimerizacijom prijenosom atoma (ATRP). U četvrtom koraku proveden je ponovno ATRP uz dodatak sredstva za umrežavanje
(2-okso-1,3-dioksolan-4-il)metil metakrilat (GCMA) kako bi se dobio kovalentno umreženi vodljivi polimer X-PEDOT-g-PEG. Dobiveni uzorci karakterizirani su nuklearnom magnetskom rezonancijom (NMR), infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), termogravimetrijskom analizom (TGA)i diferencijalnom pretražnom kalorimetrijom (DSC).
Na temelju dobivenih uzoraka pripremljene se tinte za inkjet ispis na savitljivu podlogu poliuretana (PU). Ispisanim slojevima na podlozi ispitana je električna provodnost te mehaničko svojstvo istezljivosti. Rezultati dobiveni FTIR i NMR analizom potvrđuju uspješnost sinteze PEDOT-g-PEG, dok DSC analiza pokazuje temperaturu staklastog prijelaza ispod tjelesne temperature (37 °C) što omogućuje savitljivost graft kopolimera u kontaktu s kožom. Vrijednosti električne provodnosti su u rangu poluvodiča, a istezanjem od 50 % ne zaostaje trajna deformacija te nije uočena značajna promjena elektrokemijske aktivnosti. Na temelju cjelokupnih rezultata sintetizirani graft kopolimer PEDOT-g-PEG mogao bi imati potencijalnu primjenu u polju nosive elektronike.Since their discovery, electrically conductive polymers have attracted attention due to their properties such as corrosion resistance, electrical conductivity, and low density. The property of electrical conductivity is made possible by the alternating arrangement of single and double bonds and the introduction of a free charge carrier. One of the main representatives of electrically conductive polymers is poly(3,4-ethylenedioxythiophene) (PEDOT) due to its good chemical stability, biocompatibility, low production cost and electrical conductivity in the semiconductor field. The introduction of poly(ethylene glycol) side branches (PEG) improves stretchability and flexibility due to the formation of non-covalent cross-links by hydrogen bonding, allowing potential application in the field of portable electronics. With additional crosslinking agents, it is possible to achieve full covalent crosslinking, which further increases the extensibility and also improves the resistance to chemicals. The synthesis of the graft copolymer was carried out in four steps. In the first step, the bromofunctionalized thiophene monomer ThBr was synthesized, and in the second step, the macroinitiator PEDOT-Br was synthesized. The graft copolymer PEDOT-g- PEG was then synthesized by grafting PEG side chains onto the PEDOT-Br main chain by atom transfer radical polymerization (ATRP). In the fourth step, ATRP was performed again with an additional crosslinking agent (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (GCMA) to obtain the covalently crosslinked conducting polymer X-PEDOT-g- PEG. The obtained samples were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The obtained samples were used to prepare inks for inkjet printing on a flexible polyurethane substrate (PU). The printed layers on the substrate were tested for electrical conductivity and mechanical deformability. The results of FTIR and NMR analysis confirm the success of PEDOT-g- PEG synthesis, while DSC analysis shows that the glass transition temperature is below the body temperature (37 °C), which allows the sustainability of the graft copolymer in contact with the skin. The electrical conductivity values are in the range of semiconductors, and a strain of 50% does not cause permanent deformation, while no significant change in electrochemical activity was observed. Based on the overall results, the synthesized graft copolymer PEDOT-g- PEG could have a potential application in the field of wearable electronics
Cleaning of ultrafiltration membranes after textile wastewater treatment
No full textOčuvanje vodenog okoliša gorući je problem modernog društva zbog sve veće industrijalizacije i rastućeg broja stanovništva. U ovom radu ispitivala se obrada tekstilne otpadne vode (TOV) korištenjem ultrafiltracijskih (UF) membrana različitih tipova, GH, GK, PT, PU i MW membrane, i njihovo čišćenje. Analizirane se karakteristike tih membrana, prije obrade TOV-a, nakon obrade TOV-a i nakon čišćenja membrana. Pratio se protok membrana kroz sve faze obrade i čišćenja, zatim su se odredile karakteristike TOV-a i permeata, i na posljetku je napravljena analiza membrana s infracrvenim sprektrofotometrom s Fourierovom transformacijom (FTIR). Ovaj integrirani pristup omogućava bolje razumijevanje i učinkovitiju obradu TOV-a, što ima ključnu važnost za očuvanje okoliša i održivo upravljanje tekstilnom industrijom. Tijekom obrade TOV-a navedenim membranama došlo je do blokiranja što se primijetilo padom protoka. Nakon čišćenja membrana protok se vratio na početne vrijednosti za sve membrane čime čišćenje možemo smatrati uspješnim. FTIR analiza je pokazala da je došlo do interakcija između TOV-a i membrana koja čišćenje nije uspjelo ukloniti, ali to nije utiecalo na protok membrana.The preservation of aquatic environment is an urgent problem of modern society due to increasing industrialization and growing population. In this work, the treatment of textile wastewater (TWW) with ultrafiltration (UF) membranes of different types, GH, GK, PT, PU and MW membranes, and their cleaning were examined. The characteristics of these membranes were analyzed before TWW treatment, after TWW treatment, and after membrane cleaning. The flow of the membranes was monitored at all stages of treatment and cleaning, then the characteristics of TWW and permeate were determined, and finally FTIR analysis of the membranes was performed. This integrated approach allows a better understanding and more efficient processing of TWW, which is crucial for environmental protection and sustainable management of the textile industry. During the treatment of TWW with the mentioned membranes, blocking occurred, which was noticed by the drop in flow. After cleaning the membranes, the flow returned to the initial values for all membranes, which means that we can consider the cleaning successful. FTIR analysis showed that there were interactions between the TWW and the membranes that the cleaning failed to remove, but this did not affect the flow of the membranes
Interactions at the polymer-filler interface
No full textSvojstva višefaznih sustava kao što su polimeri punjeni anorganskim česticama ovise o sastavu, morfologiji i svojstvima pojedinih konstituenata kao i o prirodi interakcija (adheziji) na međupovršini polimer/punilo. U ovom radu cilj je bio istražiti utjecaj neobrađenog Aerosil 200 i heksadecil silanom obrađenog, R816 nanopunila, amorfne pirogene silike na svojstva kompozita s polistirenom visoke udarne žilavosti (HIPS). HIPS+nano-SiO2 kompoziti pripravljeni su s 0,5; 1; 3 i 5% masenih udjela punila u Brabender gnjetilici zamješavanjem u talini. Utjecaj dodatka neobrađenog i silanom obrađenog nano-silika punila na međupovršinske interakcije, toplinska i mehanička svojstva HIPS/A200 i HIPS/R816 kompozita istražen je primjenom tehnike kontaktnog kuta, diferencijalne pretražne kalorimetrije (DSC) i rasteznog ispitivanja. Svojstva međupovršine u kompozitu predviđena su na osnovi proračunatih vrijednosti parametara adhezije: termodinamičkog rada adhezije, slobodne energije međupovršine i koeficijenta razlijevanja.The properties of multiphase systems such as polymers filled with inorganic particles depend on the composition, morphology, and properties of the individual constituents, as well as on the nature of the interaction (adhesion) at the polymer/filler interface. In this work, the influence of untreated Aerosil 200 and hexadecylsilane-treated Aerosil R816 nano-filler, amorphous fumed silica, on the properties of high impact polystyrene (HIPS) composites was investigated. HIPS+nano-SiO2 composites were prepared with 0.5; 1; 3 and 5 % mass fraction of filler by the Brabender kneading by melt mixing. The influence of the addition of untreated and silane-treated nano-silica fillers on the interfacial interactions, thermal and mechanical properties of HIPS/A200 and HIPS/R816 composites was investigated using the contact angle technique, differential scanning calorimetry (DSC) and tensile tests.
The properties of the interface in the composition are predicted based on the calculated values of the adhesion parameters: thermodynamic work of adhesion, free energy of the interface and the spreading coefficient