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Everyday life conveniences and activities such as washing clothing made of synthetic fibers, tire wear, and plastic packaging break down in the environment may serve as an abundant source of microplastic (MP). There is plenty of evidence that microplastic is a problem due to its shape, size, and concentration and the fact that it can easily enter the food chain which causes negative impacts on human health and the environment. An important aspect of this problem is also the fact that microplastic and other contaminants of emerging concern (CEC) present in water can interact, in terms of the adsorption of CEC onto the MP surface. The adverse effect of MP in water is therefore influenced by factors affecting adsorption capacity: particle size, specific surface area, hydrophobicity, and polarity of MP as well as CEC. The aim of this study was to investigate the aquatic toxicity of pristine and photooxidative (UV) aged microplastics and pesticide atrazine samples after the sorption. For that purpose, we investigated the impact of UV aging on polyethylene terephthalate (PET) bottles and correlated it with surface properties. Polyethylene terephthalate was inspected for morphology changes using Scanning Electron Microscopy and Fourier Transformation Infrared Spectroscopy. The specific surface was investigated by using Brunauer-Emmet-Teller Analyzer to determine the adsorption capacity of MP. The fragmentation of PET bottles into microplastic particles has also been investigated. In adsorption tests, using pristine and aged PET MP, the concentration of atrazine in the aqueous phase was monitored using High-Performance Liquid Chromatography Analysis. Aquatic toxicity samples were assessed by exposing freshwater organisms to the aqueous dispersion of pristine and aged MP, without and with adsorbed pollutants. Acute toxicity bioassays were performed with the microalgae Pseudokirchneriella subcapitata (Selenastrum capricornutum) and the crustacean Daphnia magna according to standard procedures (ISO). Obtained results indicated that UV aging resulted in changes in PET bottle morphology and structure. Carboxyl groups are confirmation of surface degradation. The adsorption capacity of MP increases with a higher aging degree. Adsorption capacity is decreasing with an aging degree. Toxicity is increasing with the complexity of samples but decreases with the aging degree. Mixture (MP and CEC) confirmed higher toxicity in comparison to the individual components.

Sources of microplastic (MP) in the environment are various including inefficient wastewater treatment plants, and stormwater runoff. Also, everyday activities that produce municipal plastic waste due to unregulated waste management end up in the aquatic environment which with time can be degraded and fragmented into MP particles. Due to its shape and size, MP can easily enter the food chain and cause negative effects on the organisms. Also, it is important to notice that in atmospheric conditions waste polymer material as well as MP can release additives that are mostly residue from the synthesis or even can be produced in the process of recycling. The aim of this study was to investigate the qualitative content and aquatic toxicity of samples during the leaching process. For that purpose pristine and photooxidative (UV) aged polyethylene terephthalate (PET) bottles were exposed to the enhanced atmospheric conditions. In leaching tests, using pristine and aged MP, the concentration of bisphenol A (BPA) in the aqueous phase was monitored using High-Performance Liquid Chromatography Analysis. Heavy metal concentration was monitored using Inductively Coupled Plasma Mass Spectrometry. Acute toxicity bioassays were performed with the freshwater microalgae Pseudokirchneriella subcapitata (Selenastrum capricornutum) and the crustacean Daphnia magna as well as marine bioluminiscent bacteria Vibrio fischeri, according to standard procedures (ISO). Obtained results indicate that the fragmentation of PET bottles is enhanced for pristine PET bottles in terms of a higher percentage of smaller particles. Leachates that are released from both pristine and aged PET samples were BPA and antimony. The release of antimony was much lower from the UV-aged sample. In general, presence of leached constituents enhances overall toxicity effects in comparison with the samples that consisted of only MP particles. These results will serve as preliminary study for the further investigation of microplastic behaviour in the aquatic environment and the goal is to step forward to the more complex environmentally relevant samples which are considered as a mixture of microplastics and other pollutants.

Pyrolysis Kinetic Study of the Plastic Food Packaging Waste Stream

Microplastics (MPs) are polymer particles smaller than 5 mm, and due to their potentially harmful effects on the environment are considered a global threat. MPs have a large specific surface area, and the most common sorption mechanism of organic pollutants is hydrophobic. The aim of this work was to establish the correlation between the properties of MPs and the adsorption capacity for the investigated pollutants as well as toxicity effects on tested organisms. For that purpose, we investigated the interactions of pristine and UV- aged polypropylene (PP) MPs with pesticide simazine (SMZ). The concentration of the pesticides was monitored by High-Performance Liquid Chromatography coupled with Photodiode Array Detector. Density functional theory (DFT) was applied for the investigation of the interaction energies in order to clarify the nature of the adsorption and the bonding types. Aquatic toxicity was assessed by exposing the MPs samples to crustacean Daphnia magna according to the standard procedure ISO 6341:2012. The adsorption isotherms of SMZ on PP showed the best fit for the Langmuir model which implies a monolayered adsorption process. Aquatic toxicity effects were enhanced in the case of UV-aged MPs, which is noticed as an increase in the dilution factor of such samples.

Microplastic pollution has become a growing problem worldwide. Microplastic (MP) in the aquatic environment enter the food chain and cause negative impacts on human health and the ecosystem. MP serve as a vector for various substances present in water, including emerging and priority pollutants such as pharmaceutics and pesticides. The adverse effect of MP in water is therefore influenced by factors affecting adsorption capacity ; particle size, specific surface area, aging degree, crystallinity, and polarity of MP, and the properties of organic pollutants. In this study, we investigated the interactions of polyethylene terephthalate (PET) MP with pharmaceutics and pesticides in water. The aim was to establish the correlation between the properties of MP and the adsorption capacity for the studied pollutants, and to elucidate the resulting toxic effect. For that purpose, we tested the adsorption of pharmaceutic diclofenac and pesticide atrazine on PET MP of different particle sizes and aging degree. PET was inspected for morphological changes, induced by accelerated aging under UV irradiation, using Fourier Transformation Infrared Spectroscopy and Differential Scanning Spectroscopy techniques. In adsorption tests, using pristine and aged PET MP, the concentration of pollutants in aqueous phase was monitored by HPLC analysis. Aquatic toxicity of MP was assessed by exposing freshwater organisms to the aqueous dispersion of pristine and aged MP, without and with adsorbed pollutants. Acute toxicity bioassays were performed with the microalgae Pseudokirchneriella subcapitata (Selenastrum capricornutum) and the crustacean Daphnia magna according to standard procedures (ISO). It was shown that the toxicity of MP increases with the aging degree which is correlated with enhanced adsorption capacity owing to morphological changes and the formation of surface functional groups during accelerated aging, as confirmed by the observed changes in carbonyl index. Complex samples indicated additive toxicity effects in the case of both organisms, in comparison with the individual components, indicating the complexity of the emerging problem of MPs in the aquatic environment.

Multi-layered plastics are a great challenge for the waste recycling industry. The majority of multi-layered plastics consist of two or more types of polymers, making it difficult to recycle mechanically, which leads to landfill or incineration plant. As a way of thermochemical recycling, pyrolysis is a promising cleaner technology that could use multi-layered waste plastics potential and convert it into valuable products like fuels and chemicals. To better understand the pyrolysis process of multi-layered plastics, thermogravimetric analysis was carried out to determine their thermochemical behaviour and kinetic parameters. Thermogravimetric measurements were conducted in a nitrogen atmosphere at heating rates of 5, 10, 15 and 20 °C/min in the temperature range 40−600 °C. Kinetic analysis was done using the isoconversional model- free Friedman method in combination with an advanced statistical approach. Thermogravimetric analysis revealed how decomposition occurs in the range 350−510 °C and the weight loss >90% indicating high volatile matter content, hence potential for pyrolytic oil production. The results of the kinetic analysis showed how pyrolysis of multi-layered plastics is a complex process consisting of three decomposition stages. The activation energy values determined by Friedman were rising with the degree of conversion from 127 kJ/mol at 0.01 to 219 kJ/mol at 0.95.

The presence of contaminants of emerging concern (CECs) in aquatic environment represents the risk due to potential adverse effects on both human health and the environment. The term CECs does not only apply to chemical contaminants but to the microplastics (MPs) as well. As MP may interact with the co-pollutants present in water through sorption, it may serve as a vector for accumulated chemicals, altering their environmental behavior and overall toxicity. We investigated adsorption behaviour of pharmaceutical by pristine and aged MPs. The study is aimed at establishing correlation between structural characteristics of MPs and adsorption capacity at varied conditions. For that purpose, polyethhylene teraphthalate (PET) MPs were used as the most abundant type in aquatic environment in the combination with diclofenac as the representative of widely used pharmaceuticals. The adsorption experiments were performed according to the statistical planning, whereas the level of MPs aging, as well as pH and temperature were used as influential factors. The results were modelled using the principles of response surface methodology and the corresponding adsorption isotherms were established. The toxicity of MPs/diclofenac was assessed using freshwater green algae Selenastrum capricornutum according to the standard method ISO 8692:1989.

Plastična prehrambena ambalaža veliki je izazov za reciklažnu industriju. Većina prehrambene ambalaže sastoji se od dvije ili više vrsta polimera. Takva višeslojna plastična ambalaža pruža dobra mehanička svojstva s barijerama protiv vlage, svjetlosti i kisika kako bi se osigurao dulji vijek trajanja proizvoda. Međutim, zbog različitog sastava ambalaže, zahtjevno je provesti mehaničko ili kemijsko recikliranje tih materijala, što ih dovodi do odlagališta ili postrojenja za spaljivanje otpada. Piroliza je alternativna tehnologija kojom se termokemijski recikliraju miješani plastični otpad i polimerni materijali koje je teško reciklirati mehanički. Stoga se piroliza javlja kao obećavajuća, ekološki prihvatljiva metoda obrade otpadne prehrambene plastične ambalaže. U usporedbi sa spaljivanjem, u pirolizi se ulazni materijal ne koristi za izravnu proizvodnju energije već se dobiva pirolitičko ulje, plin i kruti ostatak, koji se dalje mogu koristiti za proizvodnju goriva, energije i kemikalija. Za bolje razumijevanje procesa pirolize prehrambene plastične ambalaže, provedena je termogravimetrijska analiza kako bi se utvrdilo termokemijsko ponašanje i kinetički parametri. U ovom istraživanju odabran je skup reprezentativnih uzoraka prehrambene ambalaže s poznatim omjerima polimera. Termogravimetrijska mjerenja provedena su u atmosferi dušika pri brzinama zagrijavanja od 5, 10, 15 i 20 °C/min u temperaturnom rasponu 40- 600 °C. Kinetička analiza provedena je bezmodelnom izokonverzijskom Friedmanovom metodom u kombinaciji s naprednim statističkim pristupom.

Otpadna plastika krajnjih potrošača koja se ne može mehanički reciklirati predstavlja zabrinjavajuće ekološko pitanje. Prema najnovijim dostupnim podacima za Europu (Plastics-the Facts 2019), čak 25% sakupljene otpadne plastike nakon konzumiranja odlaže se na odlagališta, 43% se energetski oporabljuje i 32% reciklira. Jedan od mogućih načina obnavljanja plastike koja se ne može reciklirati (NRP) je piroliza koja se smatra ekološki prihvatljivom tehnologijom za dobivanje goriva ili kemikalija iz plastičnog otpada. Da bi se riješio izazov oporavka NRP-a pirolizom, potrebno je odrediti njegov stvarni sastav. Izvedeno je vizualno odvajanje sakupljenog NRP, a korištena je infracrvena spektroskopija s Fourierovom transformacijom (FT-IR) kako bi se potvrdila točnost vizualnog odvajanja. Pronađena je značajna količina plastike koja je označena kao "ostalo". Budući da sastav te otpadne plastike nije dovoljno istražen, pronađeno je vrlo malo studija o njenoj pirolizi. Stoga je karakterizirana i dodana smjesi s drugim pronađenim polimernim vrstama NRP. Termogravimetrijska analiza (TGA) provedena je kako bi se utvrdilo termokemijsko ponašanje i kinetički parametri, što je potrebno za laboratorijska ispitivanja pirolize. TGA mjerenja provedena su pri brzinama zagrijavanja od 5, 10 i 15 ° C/min u temperaturnom rasponu 40-600 ° C s protokom dušika. Kinetička analiza provedena je izokonverzijskom bezmodelnom Friedmanovom metodom i metodom nelinearne multivarijatne regresije. Cilj ovog rada bio je analizirati kinetiku procesa pirolize NRP uz zeolitne katalizatore (Fe-ZSM i FCC). Otkriveno je kako se razgradnja NRP odvija u dva stupnja. Energija aktivacije NRP-a iznosila je 144 kJ/mol u prvoj fazi razgradnje i 262 kJ/mol u drugoj fazi razgradnje i smanjila se za 34% i 6, 5% nakon dodavanja FCC katalizatora, a za 41% i 18, 3% s dodatkom Fe-ZSM katalizatora.

Tijekom ručnog razvrstavanja plastičnog otpada krajnjih potrošača, u značajnoj količini je pronađena plastika označena kao tip sedam. Većina plastičnog otpada tipa sedam je višeslojna plastika koja se sastoji od dvije ili više vrsta polimera, što otežava mehaničku reciklažu, pa se obično spaljuje. Piroliza, kao način termokemijske reciklaže, danas je široko korištena tehnologija za pretvaranje otpadne plastike u vrijedne proizvode poput goriva i kemikalija. Da bi se dobio optimalni pirolitički proizvod, potrebno je kontrolirati sastav sirovine. Sastav otpadne plastične struje tipa sedam još nije dovoljno istražen. Stoga je karakterizacija te struje izvršena upotrebom infracrvene spektroskopije s Fourierovom transformacijom (FT-IR) za identifikaciju vrsta polimera. Nadalje, provedena je termogravimetrijska analiza (TGA) kako bi se utvrdilo termokemijsko ponašanje i kinetički parametri, što je potrebno za daljnja istraživanja u laboratorijskom reaktoru. TGA mjerenja provedena su u atmosferi dušika pri brzinama zagrijavanja od 5, 10 i 15 ° C/min u temperaturnom rasponu 40-600 ° C na zeolitnim katalizatorima. Kinetička analiza provedena je pomoću izokonverzijske Friedmanove metode u kombinaciji s multivarijantnom metodom nelinearne regresije. Rezultati kinetičke analize pokazali su složeni mehanizam razgradnje otpadne plastike tipa sedam. Vrijednosti prividne energije aktivacije za fleksibilne plastične folije snižene su dodatkom željezovog (III) oksida na ZSM-5 katalizatoru. Isto je postignuto i za krutu plastiku s dodatkom FCC katalizatora.

This paper investigated the mechanical properties of paperboards (GD2, grammage: 230 g/m2, 280g/m2 and 350 g/m2) with biodegradable polymer coating (polycaprolaton) in order to improve the properties of the material. Polycaprolactone (PCL) coating is further modified by the addition of nanoparticles of alumina (Al2O3), silicon dioxide (SiO2) and zinc oxide (ZnO). The investigated mechanical properties were tensile strength, tensile elongation, bending resistance, double folding resistance, and burst resistance and abrasion test. Prepared samples of coated paperboards were exposed to accelerated degradation (120h). During this time every 24h, colorimetric properties were measured to examine the lightfastness of the print. The study proved that the mechanical properties of the coated paperboard were not impaired. Results of tensile strength, tensile elongation, bending resistance, double folding resistance, and burst resistance point to a minor improvement of paperboard properties. There is an evident increase of abrasion resistance thereby achieving better protection of the print. All samples with nanoparticles have achieved a certain increase of lightfastness.

Otpadne vode ekološki su problem jer su vrlo često opterećene nepoželjnim, često i toksičnim organskim spojevima. Zbog toga ih je prije ispuštanja u okoliš potrebno obraditi različitim metodama. U današnje doba se sve više uz klasične mehaničke, fizikalne i biološke metode koriste napredni oksidacijski procesi. Fotokataliza, jedan od naprednih oksidacijskih procesa, zasniva se na razgradnji onečišćavala uz prisutnost katalizatora čije djelovanje aktivira svjetlost. Kao najčešći fotokatalizator koristi se metalni poluvodič titanijev dioksid (TiO2). Zbog velike energije zabranjene zone TiO2 je aktivan samo pod UV svjetlom pa su u radu sintetizirani kompozitni fotokatalizatori na bazi elektrovodljivog polimera poli(3, 4-etilendioksitiofen) (PEDOT) koji zbog male energije zabranjene zone apsorbira vidljivo zračenje, te proširuje aktivnost TiO2 u vidljivi dio spektra. Kemijskom polimerizacijom sintetizirani su kompozitni fotokatalizatori PEDOT-a i TiO2 uz oksidanse željezov(III)klorid i amonijev persulfat (APS), te različite početne molarne udjele monomera EDOT-a od 2, 6 i 10 %. Karakterizirani su infracrvenom spektroskopijom, termogravimetrijskom analizom, pretražnom i transmisijskom elektronskom mikroskopijom, difuznom reflektancijskom spektroskopijom i plinskom adsorpcijsko-desorpcijskom analizom. Fotokatalitička aktivnost ispitana je praćenjem razgradnje modelnog onečišćivala bisfenola A (BPA) pod simuliranim Sunčevim zračenjem na tekućinskoj kormatografiji visoke učinkovitosti. U svrhu optimiranja uvjeta fotokatalize i pronalaska optimalnog pH, udjela PEDOT-a i koncentracije fotokatalizatora osmišljen je Box- Behnken plan eksperimenta. Rezultati su pokazali da je površina TiO2 jednoliko prekrivena slojem PEDOT-a debljine 5 do 10 nm te da se sintetiziranim fotokatalizatorima pod simuliranim Sunčevim zračenjem može ukloniti preko 50 % BPA u 60 minuta.

The biggest producer of plastic products today is the packaging industry which makes up for almost 40% of European plastic converter demand. In one year roughly 80% of produced plastic packaging in Europe turns into waste. In 2016, for the first time, a larger share of overall collected post- consumer plastic waste in Europe was recycled (31%) than landfilled (27%), while the rest was energy recovered (42%) mostly by incineration. Pyrolysis, a thermochemical degradation, is a promising technology used to valorise plastic waste by converting it into valuable products, such as fuels and chemicals. Most common polymers used in the packaging industry are high and low- density polyethylene (HDPE and LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). From those, PVC and PET are not preferable components in the feedstock for pyrolysis process because of the formation of corrosive and toxic compounds. As pyrolysis reactor design is conditioned by prediction of the thermochemical behaviour and kinetic parameters of feedstock, in this research thermogravimetric analysis (TGA) was carried out on various mixtures of waste plastics containing HDPE, LDPE, PP, and PS in ratios that are determined by the actual plastic mix in Europe. TGA was carried out in a nitrogen atmosphere over a set of heating rates (5, 10, 15 and 20 °C/min) within a temperature range 40−600 °C. Kinetic analysis was performed using the isoconversional (Kissinger–Akahira–Sunose) method. Aim of this paper was to investigate the kinetics of the pyrolysis process of polymer mixtures using Ni- or Fe- based catalysts on γ- Al2O3 as a support. The results of the kinetic analysis showed that degradation mechanism of the polymer mixtures was complexed because of the variation in apparent activation energy with the conversion. The value of apparent activation energy for actual plastic mix (22% HDPE, 31% LDPE, 35% PP, 12% PS) was in range 180.8−208.3 kJ/mol. With the addition of catalyst Fe/γ-Al2O3 it lowered to 161.5−182.8 kJ/mol, and to 170.6−183.9 kJ/mol with Ni/ γ- Al2O3 catalyst.

Tijekom posljednjih desetljeća korištenje polimera kao materijala za pakiranje hrane izrazito je poraslo zbog svojih prednosti u odnosu na druge tradicionalne materijale. Život suvremenog čovjeka nije moguće zamisliti bez ambalaže tj. materijala za pakiranje hrane. Pakiranjem se namirnica štiti od različitih vanjskih utjecaja tijekom njezine distribucije od proizvodnje do potrošača, a pritom joj se čuva nutritivna vrijednost i zdravstvena ispravnost. Međutim, usprkos nizu dobrih svojstava polimera kao što su mehanička (žilavi, fleksibilni, čvrsti), kemijska (inertni, netoksični, netopljivi, dobrih barijernih svojstava) i fizikalna (niske gustoće, toplinski postojani), suvremena znanja i tehnologije unaprjeđuju ta svojstava. Tako je za polimernu ambalažu važno da štiti proizvod/namirnicu od mehaničkih utjecaja (udara, loma), a često su od presudnog značaja i toplinska svojstva jer mora podnijeti veliku razliku u temperaturi kao npr. kod sterilizacije i smrzavanja hrane. Danas je posvećena povećana pozornost zdravstvenoj ispravnosti novih polimernih materijala za pakiranje hrane zbog modifikacija različitim aditivima. Također, značajno svojstvo ambalažnih polimernih materijala je njihova niska cijena, tj. ekonomska isplativost i laka dostupnost. No, najveća pažnja poklanja se poboljšanju barijernih svojstva, smanjenju propusnosti na kisik, vodenu paru, ugljikov dioksid i organske pare budući da utječu na kvarenje hrane, promjenu okusa i na značajno smanjenje nutritivne vrijednosti hrane uslijed svjetla, topline, vlage i pojave mikroorganizama. Stoga su suvremena istraživanja o materijalima i nanomaterijalima pristupila rješavanju tog problema s različitih aspekata, kao na primjer modifikacijom polimera tijekom sinteze ili tijekom prerade/pripreme ambalažnih materijala. Prvi korak je odabir polimera zadovoljavajuće primarne molekularne strukture (povećana kristalnost, smanjenje interakcije s permeatom). Zatim ugradnja funkcionalnih skupina u osnovni polimerni lanac ili graftiranje bočnih skupina na lanac, te priprema višeslojnih filmova/folija iz različitih polimera i/ili iz filmova različitih materijala (papir, aluminijska folija), kao i modifikacija polimera mikro i nanočesticama. U tu svrhu mogu se koristiti različite aktivne tvari kao što su: magnetit, cinkov oksid, aluminijev oksid, titanijev dioksid, srebrni ioni, zeolit i montmorilonitna glina s ciljem unaprjeđivanja specifičnih, pojedinih funkcijskih svojstava ambalaže uz zadržavanje zdravstvene ispravnosti.

By in-situ chemical oxidation polymerization polypyrrole/titanium dioxide (PPy/TiO2) nanocomposite photocatalysts were prepared for photocatalytic wastewater purification under simulated solar irradiation. To enhance TiO2 photoactivity under visible light and to reduce economic expenses during wastewater treatment PPy conductive polymer was applied. Conductive PPy polymers with extending conjugated electron systems act as stable photosensitizers injecting electrons into the conduction band of TiO2 (due to their π conjugated electrons). This study aimed to elucidate the stability and loss of conductivity under alkaline conditions during photocatalysis. The deprotonation, which is responsible for conductivity reduction, is discussed on the bases of salt–base transition in polypyrrole due to treatment of nanocomposite by ammonium hydroxide (NH4OH). The stability towards the loss of conductivity by deprotonation was validated by measuring the electrical conductivity and photocatalytic activity. Further, studied PPy/TiO2 nanocomposite photocatalysts were characterized by FTIR and UV/Vis spectroscopy, TG analysis and SEM microscopy. Photocatalytic activity of PPy/TiO2 nanocomposite photocatalysts was estimated by monitoring the discoloration of Reactive Red (RR45) azo dye in wastewater by UV/Vis spectrophotometer at the maximum wavelength (λmax=542 nm). The kinetics of photocatalytic degradation rate of RR45 was studied as well. The mineralization process was followed by determination of total organic carbon (TOC). From the results it was concluded that deprotonation process significantly decreased the conductivity of PPy/TiO2 nanocomposite photocatalysts since the conductivity of 17.6 S/cm was observed after in-situ synthesis and 7.1 x 10-5 S/cm was notified after the deprotonation. The consequence of deprotonation was also lower photocatalytic degradation rate of RR45 dye in wastewater purification.

Jedna od posebnih vrsta aktivnih polimernih materijala su polimerni kompoziti s UV blokirajućim djelovanjem. Da bi se postiglo UV blokiranje, potrebno je u polimernu matricu dodati aktivne komponente koje karakterizira funkcijsko svojstvo UV zaštite. U ovom radu, pripremljeni su kompoziti na bazi polietilena niske gustoće (LDPE) s punilom, tj. aktivnom tvari s potencijalnim svojstvom UV blokiranja. Kao punilo u polimernu matricu dodani su metalni oksidi (TiO2, ZnO i SiO2) ili isti metalni oksidi uz dodatak srebra. Polimerni kompoziti pripremljeni su u Brabender gnjetilici te su zatim isprešani u folije kako bi se provela karakterizacija uzoraka. Tako pripremljeni uzorci karakterizirani su FTIR spektroskopijom, termogravimetrijskom analizom, UV/Vis spektroskopijom te su im ispitana barijerna i mehanička svojstva. Provedene analize pokazale su kako dodatkom punila dolazi do poboljšanja prvotnih svojstava čistog polimera te ga čini prikladnim materijalom za ambalažu. Rezultati pokazuju da se dodatkom punila i u maloj količini može postići zadovoljavajuća UV zaštita. Dodatak srebra povećava apsorpcijsku moć metalnih oksida, a samim time polimerne kompozite čini još stabilnijim na UV/Vis zračenje.

In-situ sintezom, kemijskom oksidacijskom polimerizacijom monomera pirola, pripremljen je polipirol/titanijev dioksid (PPy/TiO2) nanokompozitni fotokatalizator, za fotokatalitičko pročišćavanje otpadnih voda uz simulirano Sunčevo zračenje. Kao oksidans korišten je željezov(III) klorid (FeCl3), a sinteza se odvijala pri temperaturi od 5 °C u trajanju od 270 minuta. Proces deprotoniranja vodljivog polimera PPy u nanokompozitu proveden je uranjanjem u 0, 1 M otopinu amonijevog hidroksida (NH4OH) u vremenskom period od 5 min te 1, 15, 24 i 48 sati. Stabilnost prema deprotoniranju i posljedični gubitak vodljivosti u alkalnim uvjetima utvrđen je određivanjem elektrovodljvosti te fotokatalitičke aktivnosti. Uzorci PPy/TiO2 nanokompozitnih fotokatalizatora, također su dodatno karakterizirani FTIR te UV/Vis spektroskopijom. Fotokatalitička učinkovitost PPy/TiO2 nanokompozitnih fotokatalizatora praćena je razgradnjom Reactive Red 45 (RR45) azo bojila u vodi. Pad koncentracije RR45 bojila s vremenom fotokatalize praćen je UV/Vis spektroskopskim mjerenjem intenziteta apsorbancije na max = 542 nm za RR45 bojilo. Proces mineralizacije RR45 bojila (potpuna razgradnja) praćen je određivanjem ukupnog organskog ugljika (TOC) pomoću TOC analizatora. Nakon in-situ sinteze utvrđena je visoka vodljivost PPy/TiO2 nanokompozita od 17, 6 S/cm, a potom je vidljivo da je proces deprotoniranja značajno utjecao na smanjenje elektrovodljivosti (7, 1 x 10-5 S/cm). Posljedično je smanjena i fotokatalitička razgradnja RR45 bojila u vodi, a proces fotokatalize je usporen.

Fotokataliza je kemijski proces koji uključuje razgradnju onečišćenja uz prisutnost fotokatalizatora pod utjecajem svjetlosti. Najčešće primjenjivani fotokatalizator je TiO2, a kao njegovi aktivatori koriste se elektrovodljivi polimeri koji imaju malu širinu zabranjene zone i zbog toga apsorbiraju vidljivi dio zračenja te proširuju fotokatalitičku aktivnost u vidljivi dio spektra. Kemijskom oksidacijskom polimerizacijom sintetizirani su kompozitni fotokatalizatori vodljivog polimera poli(3, 4- etilendioksitiofena) (PEDOT) i TiO2 uz oksidans FeCl3. Kompoziti su sadržavali različite omjere PEDOT- a i TiO2 jer su sintetizirani uz omjere monomera i nanočestica TiO2 1:2, 1:3, 1:4, 1:5, 1:10 i 1:20. Okarakterizirani su FTIR i UV/VIS spektroskopijom, mjerenjem elektrovodljivosti i ispitivanjem morfologije na SEM mikroskopu. Fotokatalitička aktivnost ispitana je praćenjem razgradnje Acid Blue 25 bojila u vodi uz simulirano Sunčevo zračenje. Nanokompozitni fotokatalizator PEDOT-TiO2 omjera 1:20 iskorišten je za određivanje fotokatalitičke aktivnosti i ukupnog organskog ugljika (TOC) uz različite koncentracije fotokatalizatora (0, 2, 0, 5, 1 i 1, 5 g/L) i Acid Blue 25 bojila (20, 30, 40, 60 mg/L). Rezultati ispitivanja su pokazali da se povećanjem koncentracije katalizatora povećava učinkovitost fotokatalizatora, a s druge strane povećanjem koncentracije Acid Blue 25 bojila dolazi do smanjenja fotokatalitičke aktivnosti nanokompozitnog fotokatalizatora.

The main objective of this study was to develop a supported photocatalyst for wastewater treatment with extended efficiency under solar light. For that purpose titanium dioxide (TiO2) was immobilized by sol–gel synthesis on the surface of the waste fly ash (FA). On such prepared composite material, conductive polymer poly(3, 4- ethylenedioxythiophene) was grafted by in situ chemical oxidative polymerization with different oxidants, ammonium persulfate (APS), and iron(III) chloride, FeCl3. Characterization was performed by Fourier transform infrared spectroscopy, scanning electron microscopy, X- ray diffraction, thermogravimetric analysis, and gas sorption analysis. Photocatalytic activity of composite photocatalyst was evaluated by testing removal efficiency of C.I. Reactive Red 45 (RR45) azo dye in three consecutive photocatalytic cycles under different pH. Discoloration of RR45 was measured using UV/Vis spectroscopy. It was determined that oxidant type plays major role in structure of composite as sample synthesized with APS had higher fraction of polymer and largest pore volume. The same composite had much better photocatalytic efficiency than sample synthesized with FeCl3 oxidant. It was also determined that there is a very strong adsorption of dye molecules on the surface of photocatalyst that quickly causes saturation of photocatalyst and efficiency drop after first cycle.

Polianilin/cinkov oksid (PANI/ZnO) nanokompoziti sintetizirani su in-situ, kemijskom oksidativnom polimerizacijom monomera anilina, za katalitičko pročišćavanje otpadnih voda. Sinteza PANI/ZnO nanokompozita (katalizator-N) u neutralnom provedena je u vodenom mediju s određenim udjelom organskog otapala (dietilen glikol, DEG), koncentracija dietilen glikola bila je 0, 024 mol/dm3. Postupak sinteze PANI/ZnO nanokompozita (katalizator-K) u kiselom mediju modificiran je tako da je prvo kratko sintetiziran čisti PANI polimer, a potom je nastavljena in-situ sinteza uz prisustvo ZnO nanočestica. Čisti ZnO i sintetizirani PANI/ZnO nanokompozitni fotokatalizatori karakterizirani su FTIR spektroskopski te im je određena elektrovodljivost. Fotokatalitička učinkovitost PANI/ZnO nanokompozitnih fotokatalizatora ocijenjena je analizom efikasnosti razgradnje Acid Blue 25 (AB25) bojila u vodi pod djelovanjem simuliranog Sunčevog zračenja. UV/VIS spektrofotometrijski praćeno je obezbojenje u vodi, određivanjem absorbancije na λmax = 622 nm za AB25 bojilo. Rezultati istraživanja pokazuju da PANI/ZnO nanokompozitni fotokatalizatori sintetizirani u neutralnom mediju s DEG otapalom imaju relativno dobru efikasnost fotokatalitičke razgradnje AB25 bojila dok fotokatalizatori sintetizirani u kiselom mediju imaju nižu efikasnost razgradnje uz simulirano Sunčevo zračenje.

TiO2 is an excellent photocatalyst under UV light but its high band gap limits its activity under visible light and restricts the practical application. The PEDOT conductive polymer was used to increase the photocatalytic activity of TiO2 as conductive polymers are known to be efficient electron donor and good electron transporters upon visible-light excitation. For that reason the nanocomposite photocatalysts of conducting polymer poly(3, 4-ethylenedioxythiophene) (PEDOT) and TiO2 nanoparticles were prepared by in-situ synthesis for catalytic waste water treatment. The synthesis was carried out by chemical oxidation polymerization with FeCl3 oxidant with the ratio EDOT monomer:oxidant 1:1, while the ratio of monomer and TiO2 nanoparticles was 1:10 and 1:20. Studied photocatalysts were characterized by FTIR spectroscopy, SEM microscopy, TG analysis and by the determination of conductivity. The photocatalytic activity was assessed through degradation of Acid Blue 25 dye (AB25) under simulated Solar irradiation. Photocatalysis was monitored by measuring discoloration of AB25 using UV/Vis spectroscopy. The kinetics of photocatalytic degradation of AB25 was determined as well. The effect of photocatalytic media on catalysts efficiency was also considered due to strong interactions between catalyst and pollutant. The results indicate the strong interactions of PEDOT polymer and AB25 because very high adsorption of dye onto PEDOT/TiO2 nanocomposite catalysts was observed. The pH media of suspension during catalytic water treatment significantly affected those interactions and photocatalysis process.

Organic synthetic dyes used in textile and food industries are major sources of the environmental contaminations due to high toxicity to aquatic species and negative impact on human health. In order to decrease damage caused by organic dye pollution the use of a semiconductor/conductive polymer nanocomposite for degradation organic compounds in contaminated water or to convert them into harmless chemicals has been extensively studied. The aim of this study was to obtain the efficient photocatalytic composite material of TiO2 and conductive polymer polyaniline (PANI) active in visible light region with core-shell structure. A facile and environmentally friendly approach has been developed for the fabrication of TiO2/PANI core–shell photocatalyst. The PANI shell was formed by in-situ polymerization of monomer aniline adsorbed on the surface of TiO2 nanoparticles. The photocatalytic activity of TiO2/PANI core-shell composite was examined in the process of degradation of the Reactive Red 45 (RR45) and Acid Blue 25 (AB25) dyes under UV and visible light irradiations. Photocatalytic activity of TiO2/PANI core-shell photocatalyst was also compared with pure TiO2 nanoparticles. The TiO2/PANI core-shell photocatalyst was characterized by FTIR spectroscopy, UV/Vis spectroscopy, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Electrical conductivity was also determined by four-point probe method. Results indicated deposition of uniform PANI layer as thin as 4 nm on the surface of TiO2 nanoparticles which improved the photocatalytic activity of pure TiO2 nanoparticles.

Low density polyethylene is a classic material used for food packaging due to numerous advantages it has, but low oxygen barrier property is its main weakness. To improve permeability properties double layer polyethylene/polycaprolactone (PE/PCL) films were prepared with the addition of zeolite or/and magnetite in PCL layer. Zeolite and magnetite nanoparticles were added as the modifiers in PCL film since they slow down the process of oxygen permeability. For the multi- component materials of great importance is matrix-filler interaction that result in better dispersion of particles in the matrix and greater adhesion. The consequence is improved performance for the new formulation strategies to develop composites have potential applications in various types of packaging (dried food, frozen food, etc.). In particularly important for the double layer films is good adhesion between two layered films that can easily separate under the mechanical stress. Food packaging, except good barrier is needed to have good thermal and mechanical properties because they have to be flexible and endure the higher temperatures, like sterilization, etc. For the studied samples oxygen permeability parameters were analyzed but also thermal and mechanical properties were determined. It is found that thermal stability and mechanical properties of double layer films compared to PE film alone were improved, especially for the samples when zeolite is modified with magnetite. Oxygen barrier performance in modified PE/PCL samples was improvement, seen in sample with higher content of magnetite in zeolite.

Paper based materials along with other synthetic polymers are the most common materials used in packaging industry. Its main advantage, that is well known fact is that cellulose materials (paper, paperboard and cardboard), are the main biodegradable fraction of the municipal solid waste (MSW). On the other hand, the biggest setback is its high water permeability when compared with plastic material. This problem can be partly solved by preparing the polymer coating paperboard packaging. Due to this problem the printed paperboard samples coated with biodegradable PCL polymer were studied in this paper. Printed paperboard samples were prepared with modified PCL coating with SiO2 (K/P/2Si), Al2O3 (K/P/1Al) nanoparticles. Characterization of the studied samples has been made by determination of water vapor transmission rate (WVTR), mechanical and visual properties of printed paperboard. Water vapor transmission rate was made with the Herfeld apparatus using 97% sulfuric acid. The mass of the container with the sample and water is measured at the beginning and after 24 and 48 hours. The burst strength (S) was determinate according to ISO 2759 while the difference of reflectance due to the presents of nanoparticle was measured with a spectrometer (380-730nm). The visual spectral reflectance of the full tone process colors of print (Cyan, Magenta, Yellow and Black) was followed. The results show that PCL and PCL coatings with implemented SiO2 and Al2O3 nanoparticles slow down the water vapor transmission rate comparing to the paperboard without coatings.

Titanium dioxide (TiO2 ; Aeroxide® P25) is one of the most famous commercial photocatalyst. TiO2 is non-toxic [1], environment friendly but with relatively high band gap of 3.2 eV that restricts its photocatalytic activity under the visible light. There were several attempts to increase the TiO2 activity under the visible light (> 400 nm) by doping and by controlling the surface/particle size [1]. However, the above attempts require the novel TiO2 preparation. The most promising solution is to prepare P25- compostites by using conductive (-conjugated) polymers such as polyaniline (PANI) [2], since they are non-toxic, thermally stable and they have a high absorption coefficient in the visible light region. When the PANI/TiO2 composite is irradiated by visible light, the PANI excited- state electrons are formed which are easily injected into the TiO2 conduction band (CB) [2]. Consequently, the injected electrons produce the superoxide radicals that oxidize the organic (dye) pollutant. The above mechanism, which enables the TiO2 photoactivity under the visible light, is one part of the synergic PANI/TiO2 effect. PANI/TiO2 composites can be prepared by chemical in situ oxidation of aniline (An) in the presence of TiO2 [3] by using ammonium persulfate (APS). However, the PANI conductivity is governed by the experimental conditions that should be carefully chosen: concentration of An and APS, m(An):m(TiO2), n(An):n(APS), type of acid, pH, etc. [2]. Obtained photocatalytic results (Fig.1) show achieved synergic PANI/TiO2 effect as the dye removal is higher for 10% PANI/TiO2 than for the pure TiO2.

Photocatalysis is the catalytic process classified as chemical method of waste water treatment. It can be carried out by using a photocatalyst such as metal oxides (TiO2, ZnO, ...). Thus, in this paper, in-situ synthesized nanocomposite of conducting polymer poly(3, 4-ethylenedioxythiophene) (PEDOT) in the presence of ZnO nanoparticles was studied. The role of the conducting polymer was to increase the photocatalytic activity of photocatalyst under simulated Solar irradiation. During the synthesis of PEDOT with ammonium persulfate (APS) the ratio of monomer: oxidant was varied (1:2 ; 1:3 ; 1:5) and obtained samples are denoted as PEDOT/ZnO (1:2), PEDOT/ZnO (1:3) and PEDOT/ZnO (1:5). Synthesized photocatalysts were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Photocatalysis is carried out under UV-A and simulated Solar irradiation where the efficacy of azo dye Reactive Red 45 (RR45) removal from water was followed by monitoring discoloration using UV/Vis spectroscopy. From the results of photocatalytic activity it can be seen that the lowest efficiency of degradation show nanocomposite with higher concentration of PEDOT polymer. TGA thermograms of PEDOT/ZnO nanocomposites synthesized by various ratio monomer:APS oxidant indicate different structure of PEDOT and its concentration in samples.

In this study nanocomposite photocatalyst of conducting polymer poly(3, 4-ethylenedioxytiophene) (PEDOT) and TiO2 has been synthesized with the aim of extending photocatalytic activity of TiO2 into the region of visible light irradiation. PEDOT/TiO2 photocatalysts were synthesized by chemical oxidative polymerization with two oxidants ; FeCl3 and ammonium persulfate (APS). Photocatalysts were characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy. Photocatalytic activity has been tested on removal of C.I. Reactive Red 45 (RR45) dye in aqueous solution by UV-A and simulated solar irradiation. UV/Vis spectrophotometric and total organic carbon (TOC) measurements were performed for determination of color removal and the extent of mineralization. It was found that nanocomposite synthesized with FeCl3 was the most efficient with superior photocatalytic activity when compared to pure TiO2. It was able to remove color in just 15 min under the solar irradiation with mineralization extent of 85% after 90 min.

In situ sintezom pirola (Py) u prisustvu nanočestica titanijeva dioksida (TiO2) pripremljeni su nanokompozitni fotokatalizatori polipirol/ TiO2 (PPy/TiO2) za pročišćavanje otpadnih voda. Za sintetizirane katalizatore očekivala se povećana efikasnost katalitičke razgradnje Acid Blue 25 (AB25) bojila u otpadnim vodama pod simuliranim sunčevim zračenjem uslijed pojave sinergističkog djelovanja PPy i TiO2. Stoga, istraživani su uvjeti sinteze fotokatalizatora kako bi se postigla odgovarajuća svojstva elektrovodljivog PPy polimera za povećanu fotokatalitičku aktivnost uz sunčevo zračenje. Tijekom in situ sinteze uzoraka (PPy/TiO2 90, PPy/TiO2 180, PPy/TiO2 270) vrijeme sinteze bilo je 90, 180 i 270 minuta, a omjer monomer: TiO2 kao i omjer monomer:oksidans održavan je konstantnim. Uzorci su karakterizirani FTIR spektrofotometrom, termogravimetrijskom analizom (TGA) te im je određena fotokatalitička efikasnost razgradnje AB 25 bojila. Ocjena njihove fotokatalitičke aktivnosti, pri simuliranom Sunčevom zračenju, određena je praćenjem obezbojenja onečišćene vode UV/VIS spektroskopijom u ovisnosti o vremenu fotokatalize. Rezultati su pokazali povećano fotokatalitičko djelovanje PPy/TiO2 nanokompozitnih fotokatalizatora uz simulrano Sunčevo zračenje u odnosu na čisti TiO2 katalizator.