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Packaging is increasingly becoming a segment of the printing industry with the highest developing rate and market demand. Additionally, the global demand for printed labels and sleeves will strongly grow in the future which will in the end affect the global market of printing equipment, printing ink and print service. Packaging, in this case pressure sensitive labels, communicates with the consumer through its design and becomes a main part of the product. In order to be functional and to give a consumer a proper information about the product, printed labels must be attractive and decorative to consumer. Besides these factors, printed labels must be stabile during their whole life cycle when they can be subjected to heat, moisture during transportation and storage or subjected to UV light or chemicals during shelf life and use. The aim of this study is to evaluate the stability of printed labels upon exposure to UV light and different chemicals. UV light and chemicals can affect the properties of prints causing the loss of labels purpose and attraction to customer.

Although the primary role of packaging is to protect its content, it also acts as the carrier of both relevant information and visual identity. To enhance its properties, packaging materials are often coated with material which could provide barrier against chemicals, atmospheric conditions, or electromagnetic radiation. This paper focuses on the change of surface properties, i.e., wetting of a coated cardboard surface when packaging material is exposed to light induced accelerated ageing. Prepared printed cardboard was coated with nanocomposites composed of commercial water-based varnish and defined mass concentration of nanosized TiO2. The prepared samples were subjected to accelerated ageing in a light chamber equipped with Xenon lamp. The characterization of the samples included determining contact angles with liquids of known surface tension and calculating surface free energy, determining water vapour transfer rate and performing burst resistance tests (Mullen burst test). It can be concluded that the UV radiation influenced the cardboard substrate and varnished samples where AcA made some changes in the polar component due to forming of new oxidation products, which are less polar from its -OH group. However, with the introduction of nanoparticles, the UV influence was lowered in terms of surface parameters. The smallest TiO2 weight ratio (0.25%) lowers the WVTR by 56%. Moreover, with increase of TiO2 nanoparticles weight ratio, water permeability decreases significantly where the 0.5% TI/NC provided the best result (decrease of63%). Regarding the mechanical properties, although bursting strength of samples coated with nanocomposites is higher than the one coated by WB, there is no visible dependence between mechanical properties and weight ratio of nanoparticles. This research showed that addition of TiO2 nanoparticles will improve commercial varnish and will increase protection against UV radiation in terms of adhesion to the substrate and water vapour barrier.

Thermochromic offset prints are exposed to UV light in an aging chamber at different time intervals for 40 hours. A commercially available offset dye (Chameleon) with an activation temperature of 27°C blue color was applied. Measurements of CIELab values ​​showed significant changes already after 1 hour of accelerated aging. The recorded IR spectra are a reflection of the overall structure of the thermochromic ink. In the spectra of illuminated thermochromic print samples in the area of ​​stretching vibrations of OH groups, a broad band originating from the OH groups of cellulose from paper is observed and covers the possibly formed stretching bands of OH groups of oxidation products. The shoulder at 1715 cm –1 , whose intensity increases with irradiation time, can certainly be attributed to carbonyl groups in the formed oxidation products (most likely ketones) and indicates the decomposition of the polymer. For durable materials, such as most coatings and plastics, short-wave UV radiation is the primary cause of cleavage of the primary covalent bonds in the polymer chain. Encapsulation with melamine resin is a common method widely described in the literature. The other materials from which the thermochromic microcapsules are made also contain -OH groups, so photooxidation of the microcapsules can be assumed. Heterogeneity in the photooxidative degradation of polymers is a well-described and established phenomenon. Although it is possible to record the Raman spectrum of a thermochromic ink, unlike ATR spectra, the Raman spectra of thermochromic prints are dominated by paper bands. Therefore, it is not possible to derive information about the structural changes of the samples during UV illumination by means of Raman spectroscopy.

Nowadays, graphic arts bindery sector has shown growing environmental awareness in reaching the targets regarding economic, social, environmental, and technological aspects. Croatian bindery small entrepreneurship sector provides a piece of work done for clients in a sheetfed offset lithographic printing manufacturing which isn’t involved in any manner in bindery manufacturing. On top of that, sustainable bindery concepts are strictly related to effective printed resources usage, in which the generated waste is reduced through numerous binding manufacturing activities. In binding sector, designing concepts help achieve less negative environmental impact. Sustainable awareness is beginning from practical work, from preparing plans and a modelling shape, in which the process of designing the three-dimensional book presents its proposed structure on a printed original scale. Bindery eco-efficiency concepts cope with manufacturing service activities, in which the printed paper sheets (or outputs) together with binding raw materials move in a specific direction through the machine operations (cutting, folding, gathering, binding, trimming, joining and surface finishing), which are predictable in edition binding. This study provides a comprehensive overview on how a new approach in book designing might contribute to reducing “nonhazardous” printed or/and bound paper output residuals which gradually appear in a specific way during book binding process. What’s more, it offers “eco-friendly book binding”, which has “the best book in class” value. This eco-efficient bound production is monitored as well as the indices of graphic arts materials are followed up throughout the working procedures under standardized circumstances. These innovative creative thinking might bring up sustainable engineering solutions or frameworks in which “the business as usual” shifts towards “the eco-friendly business”. Eco-labelled printed paper sheets, from Croatian markets, are a sustainable choice which encourages responsible business and leads to zero pollution and circular economy. However, scientists have been worried about the fact that many manufacturing sectors rely on using adhesives with non-renewable resources, which are harmful to humans. Present published literature gives a general overview on the existing advanced adhesives which have less harmful impact on environment, but at the same time have promising performances.

Thermochromic printing inks are nowdays used in a wide range of different applications, from packaging, commercial printing, protected documents, ceramics to textiles. Their poor stability when exposed to UV radiation limits their stability in external conditions. The stability of polymeric products towards oxidation and hydrolysis is one of the important factors. In this study, one thermochromic offset printing ink was printed on two different papers (wood free coated and wood free uncoated). The prints were exposed to accelerated aging and biodegradation test in order to understand the mechanisms of prints degradation in different environments. All the samples were evaluated for changes by FT-IR spectroscopy and colorimetric properties. FTIR spectroscopy showed higer changes and degradation during biodegradation test (mostly in the case of uncoated paper), implying higer rate of ink binder hydrolysis and oxidation compared to accelerated aeging test. Colorimetric measurements showed higer stability of thermochromic print on uncoated paper during UV degradation.

Papir za recikliranje se uglavnom koristi za proizvodnju recikliranog papira, ali u zadnjem desetljeću također se koristi za proizvodnju celuloznih derivata i bioetanola. Proizvodnja recikliranih vlakana iz papira najčešće se provodi procesom kemijske deinking flotacije. Također, deinking flotacija može se provoditi uporabom enzima, u kombinaciji s predobradom ultrazvukom te uz pomoć sorbensa, ali njihova primjena u postrojenjima za recikliranje papira još uvijek je ograničena. Učinkovitost tih procesa uglavnom ovisi o interakciji između papira i tiskarskih boja. Prisutnost tiskarskih boja u recikliranoj pulpi može uzrokovati probleme vezane uz zdravstvenu sigurnost zbog prisutnosti toksičnih komponenti. Štoviše, otpadne tvari od recikliranja papira također sadrže različite kemijske toksične spojeve, što rezultira visokim organskim opterećenjima. Prikupljeni papir za recikliranje ponekad je kontaminiran hranom ili je vlažan, pa se preporučuju i druge metode kao što je proizvodnja bioetanola i organsko recikliranje (biorazgradnja). Biorazgradnja papira najviše ovisi o prisutnosti kristaline / amorfne celuloze i lignina. Preporučuje se i oporavak energije putem pirolize, plinifikacije i sagorijevanja, ali samo u slučaju ako se proizvedena toplina koristi za druge primjene. U ovom radu stoga će se posebna pozornost posvetiti recikliranju i biorazgradnji termokromnih otisaka koji u današnje vrijeme nalaze primjenu u različitim proizvodima, poput prehrambene industrije gdje se koriste kao indikatori svježine i temperature. One mogu sadržavati neke toksične komponente poput bisfenola A i benzofenona. S obzirom da proces recikliranja u svrhu proizvodnje ovisi o kemijskom sastavu boje i tiskarskom procesu, cilj je ispitati mogućnost recikliranja termokromnih otisaka te analizirati kvalitetu reciklirane pulpe u smislu prisutnosti bisfenola A i teških metala. Rezultati su pokazali da se termokromni offsetni otisci teško recikliraju a dobiveni reciklirani papir sadrži bisfenol A, koji se djelomično uklanja procesom deinking flotacije. Osim proizvodnje recikliranog papira, cilj je istražiti i mogućnost biorazgradnje otisaka u anaerobnim uvjetima. Rezultati su pokazali da biorazgradnja ovisi o interakcijama s tiskarskom podlogom, tj. papirom (upojnosti boje u papir) ali i o kemijskom sastavu veziva u tiskarskoj boji.

Tema znanstvenog rada ima za cilj analitičkom metodom kolorimetrije ispitati dinamički mehanizam reverzibilnosti termokromne (TK) tiskarske boje na recikliranoj tiskovnoj podlozi. Kolorimetrijski parametri dobiveni provedenim eksperimentom interpretacija su rezultata prikupljenih spektrofotometrijskim mjerenjem atributa difuzne refleksije svjetlosti sa površine ispitivanog uzorka. Uzorak papira korišten u istraživanju je 100% reciklirani papir sa apliciranom reverzibilnom termokromnom tiskarskom bojom poznatih fizikalnih svojstava. Otiskivanje reverzibilne TK boje na tiskovnu podlogu izvršilo se ofsetnom tehnikom tiska. Tijekom provođenja eksperimenta uzorak se ponajprije izlagao kontinuiranom povećanju toplinske energije unutar temperaturnog ranga od 15 ˚C do 60˚C. Netom nakon postizanja najviše eksperimentom određene temperature kojoj se ispitivani uzorak izlagao, započela je druga faza procesa u kojemu se uzorak podvrgnuo hlađenjem sustava sa dostignutih 60˚C do 15˚C. Preciznost regulirane i distribuirane temperature definirana je u 1˚C. Boja TK otiska ovisi o temperaturi kao i o termalnoj povijesti uzorka, što ima za posljedicu histerezu boje. Iz L*(T) histereze određene su četiri karakteristične temperature za TK otisak. Površina histereze L*(T) ukazuje na razlike u svjetlini (ΔL*) koje se dešavaju u TK otisku za vrijeme procesa zagrijavanja i hlađenja pri istoj temperaturi. U idealnim bi uvjetima površina histereze bila jednaka nuli što bi ukazivalo na potpuno jednaka zabilježena svojstva svjetlosti u procesu zagrijavanja i hlađenja na jednakim temperaturama. U ovome eksperimentu histereza je opisana razlikom svjetlina između dvije boje, na jednakim temperaturama međusobno različitih procesa.

As the packaging industry is growing lately and the amount of packaging waste increases, it becomes one of the major environmental problems. Packaging waste comprising about one-third of all municipal solid waste, mainly plastic and paper based. Anaerobic degradation is one of the most environmentally friendly methods for solid organic waste treatment and widely applied for bio-energy production. In this study, the influence of screen print thermochromic ink on biodegradability aspect of three different cardboard materials (UmcaColor - UC, Propack - PP, Lux Pack - LP) were studied using the soil burial test under anaerobic conditions. Neat and printed cardboard samples were evaluated for changes over 4 months by visual examination, weight loss measurements, volatile solids reduction and surface properties. The surface free energy (SFE) and adhesion parameters were determined for all samples, and showed a very high binding of ink to all cardboard samples. Thermochromic ink reduces the biodegradation of cardboard due to strong ink adhesion on cardboard. If a large SFE interphase is, separation of ink from the substrate occurs. The highest reduction of biodegradation for printed samples was noticed for UC sample. After 120 days the total weight loss for all three neat cardboard samples was similar (about UC 38.4%, PP 34.8%, LP 31.5%). Printed samples showed lower values of biodegradation, up to 36 % reduction compared to neat samples after 120 days.

Paper is material which is mostly consisted of cellulose, hemicellulose, lignin and different additives (CaCO3, kaoline) can undergo to chemical and physical changes in different environments. This paper evaluates two mechanisms of bulky paper degradation in two conditions, accelerated aging and biodegradation under anaerobic conditions. The changes were accompanied by FT-IR spectra. Significant changes were observed during the biodegradation for cellulose characteristic bands and bands which describes the structure of the polymer, in this case, paper. Changes in the IR spectral range of 1300-1500 cm-1 shows a significant distortion of the paper structure during biodegradation. In this spectral area during accelerated aging of paper no significant changes were observed, or any changes for cellulose characteristic bands. The most significant changes for accelerated aging were observed in the area that shows paper oxidation, in IR spectrum between 1500 -1900 cm-1. In this area, disappearance of certain bands and formation of new (carbonyl group) can be noticed. Observed changes in the IR spectra indicates that hydrolysis and oxidation of organic components of paper occurred, mostly of cellulose and lignin.

Adhesives have a wide range of applications in various industries including the printing industry. Water based emulsion adhesives being used in printing industry are most often based on polyvinyl acetate (PVAc) homopolymers, especially in bookbinding for short run book production and caseing in. Polyvinyl acetate emulsion adhesive formulations are affordable, regarded as being nontoxic and easy to handle. Designing durable and quality short run products requires understanding the interactions between used materials in adhesive joint and the basic components of paper and adhesive. In this study, the adhesive parameters of polyvinyl acetate adhesive on five paper samples containing different shares of inorganic fillers (0%, 18.5%, 20.5%, 21% and 30%) have been investigated. Paper samples were investigated in the terms of surface roughness, moisture, ash and CaCO3 content. The moisture content was similar as well as surface roughness of all paper sample, except roughness of paper with 0% of inorganic fillers – filter paper. Ranking based on ash content was same as one based on CaCO3 content. Besides the different paper properties, the varying amount of water (0%, 2.5% and 5%) in adhesive have been studied as well. Polyvinyl acetate adhesive was applied on all samples under the same conditions (23°C and 50% RH) and method. The analysis of the surface free energy (SFE) and its polar and dispersive components of paper and adhesive was performed by contact angle measurements. Based on those measurements, excluding a hydrophilic filter paper again, all other paper samples showed hydrophobic character and small SFE values (under 40 mJ/m2). There was no large impact on SFE of hydrophilic adhesive samples due to added amount of water. According to the obtained results, the interfacial free energy between two phases and mechanical work of the adhesion was calculated.

The colorimetric properties of one, leuco dye-based thermochromic (TC) ink at 270C activation temperature on four different paper samples were studied. The paper samples are: filter paper, bulky paper, recycled paper and synthetic paper. The each sample was heated from the 15 0C to the 600C and then cooled back to the 150C. The colour of the ink was dependent on temperature as well as the thermal history of the sample, which gives rise to colour hysteresis. Four characteristic temperatures were determined from L*(T) hysteresis and they are the same for TC ink print on all examined papers. The differences in colour that occur on the TC print during the process of heating and cooling at the same temperature, are the highest in the case of TC print on filter paper.

As the packaging industry is growing lately and the amount of packaging waste increases, it becomes one of the major environmental problems. Packaging waste comprising about one-third of all municipal solid waste, mainly plastic and paper based. Anaerobic degradation is one of the most environmentally friendly methods for solid organic waste treatment and widely applied for bio-energy production. In this study, the influence of screen print thermochromic ink on biodegradability aspect of three different cardboard materials (Umca Color - UC, Propack - PP, Lux Pack - LP) were studied using the soil burial test under anaerobic conditions. Neat and printed cardboard samples were evaluated for changes over 3 months by visual examination, weight loss measurements, volatile solids reduction and surface properties. The surface free energy (SFE) and adhesion parameters were determined for all samples, and showed a very high binding of ink to all cardboard samples. Thermochromic ink reduces the biodegradation of cardboard due to strong ink adhesion on cardboard. If a large SFE interphase is, separation of ink from the substrate occurs. The highest reduction of biodegradation for printed samples was noticed for UC sample. After 120 days the total weight loss for all three neat cardboard samples was similar (about UC 38.4%, PP 34.8%, LP 31.5%). Printed samples showed lower values of biodegradation, up to 36 % reduction compared to neat samples after 120 days

A study about the colouring of cellulose pulp and photocopier paper by beetroot (or red beet) betalains has been carried out in this research. Cellulose pulp of 10% consistency was made entirely from cellulose filter paper and coloured using shaking without any additives and after pre-mordanting with mordants and surfactants. Direct soaking was researched as a further method of colouring ; Navigator paper and filter paper made of pure cellulose were coloured. Spectrometric analysis has shown that direct soaking is a much more efficient colouring method than colouring during paper making. Beetroot dyes bind with cellulose fibre, but the betacyanins, which are reddish to violet dyes, have great affinity to water and are easily washed out with water. Betaxanthin dyes, which are yellowish to orange, bind with cellulose fibres with higher attractive forces.

Bisphenol A (BPA ; Figure 1) is an industrial chemical with major applications in the production of polycarbonate plastics and epoxy resins. Polycarbonate is used in food storage containers, while epoxy resins are used in the internal coating for food and beverage cans. Residues of unreacted BPA can migrate into foods, and humans of different age are inevitably exposed to it. BPA acts as endocrine-disrupting compound that perturb the endocrine system either by acting as agonist or antagonist to sex hormone receptors, thus mimicking or preventing the action of endogenous estrogens and androgens. In this work BPA was determined in 3 out of 5 samples of thermochromic printing inks by gradient HPLC method. The samples were sonicated in ultrasound bath, diluted with mobile phase (acetonitrile/water 1/1) and filtered prior to analyses. The mass ratio of BPA in dyes ranged from 2.15 to 4.42 %. Unusually high results were confirmed by comparison of peak areas of BPA in standard and in dyes at two wavelengths (228 nm and 278 nm), and the ratio of peak areas was the same. Limits of detection (LOD) of BPA ranged from 9.5 to 33.5 μg/kg, whereas limits of quantification (LOQ) ranged from 28.6 to 56.0 μg/kg.

The aim of the study was to analyse the possibility of using natural zeolite clinoptilolite as partial substitute of paper filler in order to improve the UV stability of thermochromic ink. Natural zeolite tuff was added to calcium carbonate in mass proportions of 0%, 20% and 60% and laboratory handsheets were prepared with 20% filler addition to fibre paperstock. The printability tester IGT A2 was used in the preparation of thermochromic prints on laboratory handsheets, which were exposed to the process of UV radiation in aging chamber Solarbox 1500e (CO.FO.ME.GRA) at various time intervals during 40 hours. The measurements of the CIELab values (L*, a*, b* and C*) have shown changes as a function of accelerated aging time that are very significant already after 1 hour. The smallest changes were obtained in the case of paper samples with 12% clinoptilolite (20% zeolite tuff addition). It was concluded that small proportions up to 20% of zeolite tuff in paper filler act favorably on the UV stability of printed thermochromic ink, while higher proportions reduce the stability as effect of photocatalytic oxidation features due the presence of Fe-oxides in the sample of natural zeolite tuff.

Chemical properties of cationic biosorbents, the orange peel and the lemon peel, have been studied. ATR and Raman spectra indicated that the functional groups in the peels structure responsible for dye sorption are carboxyl groups (COOH and COOM, M=Na+, K+, Ca2+, Mg2+) and hydroxyl groups (OH). Increasing the mass of the peels in water suspensions a decrease in dissociation of both, the –COOH and –COOM groups was obtained. Sorption isotherms of methylene blue onto the biosorbents had two sorption plateaus. Hence the carboxyl groups interacted with methylene blue up to the first plateau, while sorption by also the hydroxyl groups occurred from the first to the second plateau. A very good agreement between the amounts of the carboxyl groups estimated in the peels and the amounts of the dye molecules sorbed onto the peels was obtained

The aim of this research was to investigate the influence of natural zeolite clinoptilolite used as filler on printability of paper and its print quality. Paper sheets were prepared with the addition of 20% of fillers, where natural zeolite were added to calcium carbonate in different u.w.% (20, 40, 60). The zeolite originates from a sedimentary deposit in Donje Jelenje, Croatia. The zeolite tuff is substantially composed from clinoptilolite. Its particle size distribution is broad and the structure is micro and mezzo porous. The addition of natural zeolite as filler resulted in higher bulk of paper sheets and more porous structure. The absorption capacity and the absorption rate slightly increased too. The roughness of surface increased leading to more hydrophobic surface. Natural zeolite with its broad particle size distribution, higher amount of large particles and yellow-green colour resulted in slightly lower opacity, ISO brightness and CIE whiteness of sheets. When used for inkjet printing the zeolite containing substrates showed positive influence on print quality. Smaller wicking and bleeding effects were noticed. The paper hue does not influence the colour density of CMYK prints.

This study examines the sorption of methylene blue on the cheap unconventional bio sorbents, citrus fruits: oranges and lemons. Bio sorbents which was used was: orange and lemon peel, seeds and pulp. The results are compared with results of sorption to mineral sorbents, zeolite clinoptilolite, Pyrolox and Birm. Sorption kinetics and the influence of pH on the sorption of methylene blue on orange and lemon peel was examined. Sorption isotherm of methylene blue onto the orange end lemon peel was determined at 25oC with the initial concentrations of methylene blue 50 – 1000 mg/dm3. The sorption kinetic data were analyzed using pseudo–first–order and pseudo–second-order models. It was found that the pseudo-second-order kinetic model was the best applicable model to describe the sorption kinetics. When the pH of the solution dyes was 2-3, the sorption of methylene blue was slightly weaker than at pH 3-6. In the studied concentration range 50-1000 mg/dm3 sorption of methylene blue on orange and lemon peel was linear, with sorption efficiency of approximately 100%. The capacity of zeolite for methylene blue was 20 mg/g. Sorption capacity of citrus waste was significantly higher than in the mineral sorbents (zeolite, Pyrolox, Birm).

Removal of synthetic dyestuffs from aqueous solution is necessary because of the frequent appearance of these dyestuffs in wastewaters generated from textile and other industries. The presence of dyes in water is undesirable since even a very small amount of these coloring agents is highly visible and may be toxic to the aquatic environment. Therefore, removal of dyes is an important aspect of wastewater treatment before discharge [1]. The present study explores the ability of orange and lemon peels to remove dye from aqueous solutions. Batch studies were carried out on a laboratory scale to evaluate the adsorption capacity of orange and lemon peels. Sorption isotherm of methylene blue (MB) on the orange and lemon peel was determinated at 250C with the initial concentratons of MB in the range 25-125mg/L. Equlibrium data were fitted to the Langmuir and Freundlich isotherm models and equlibrium was reached within 24 hours. The effects of solution pH, preparation of the sorbent (effects of hydrogen peroxide and drying (80 and 1100C)) and a role of microorganisms which have capacity to reduce MB in wastewater were also studied. Microbal decolorization processes offer a complete cleanup of pollutants in a natural way as it reduces the color components to carbon dioxide, ammonia and water by initiating cleavage of the bonds in the dyes rather than creating possible toxic fragments of dyes[2]. At pH 2.0 the sorption of dye was not favorable, while the sorption at other pHs (4-10) was remarkable. Also, it was carried out the determination of carboxylic acid groups in cellulosic fibers. The method which were used is based on hydrogen ion exchange. In principle, the total ion exchange capacity of the fibers, equivalent to the total number of carboxylic acid groups, is mesured [3]. The mesures were carried out on TOC, colorimeter and FTIR. The result showed that orange nad lemon peel was a promising for the removal of MB from aqueous solution.

The process of removal of copper ions by means of clinoptilolite type natural zeolite has been studied as a function of the particle size and temperature. Results shown that increase temperature and decrease of particle size improves removal of copper from aqueous solutions. The parabolic diffusion model well described process in all examined range of time and shows that calculated diffusion coefficients increases with temperature. This increase is more visible at higher particle sizes what assume diffusion through zeolite particle as main mass transfer mechanism. The film diffusion model provides calculation of initial sorption rate (k´) and dimensionless parameter proportional to the diffusion film thickness (xi), in relation of particle size and temperature. Diffusion from the surface of zeolite particles through the micro and macro pores is well described with homogenous diffusion model, where changes of the calculated overall rate constants is observed at 60 minute of the process. This indicates the change of mass transfer rate trough porous zeolite particle. The activation energy (Ea), activation enthalpy (delta_H), activation entropy (delta_S) and free energy of activation (delta_G) have been calculated based on kinetic data. These thermodynamic parameters characterize process as diffusion dependent, weakly endothermic and nonspontaneous, where structural changes in structure of natural zeolite particle are not observed.

Sorption/desorption interactions of three structurally different triazine herbicides (atrazine, atratone, and ametryn) and three breakdown products of atrazine (deisopropylatrazine, deethylatrazine, and didealkylatrazine) were studied in native, acidified, and organically enriched forms of two representative Mediterranean soils (terra rossa): a surface soil collected in the area of Izmir in Turkey and a subsurface soil collected at a location on the Istrian peninsula in Croatia. The native soils were of clayey to silty-clayey type and differed significantly in mineral composition and cation exchange capacity. Triazine sorption/desorption experiments were performed using a batch equilibration method [1]. Sorbate equilibrium concentrations in the aqueous phase after sorption/desorption were determined by high performance liquid chromatography using an UV diode-array detector. The results of sorption experiments, evaluated in terms of Freundlich isotherm, were compared with respect to the physicochemical properties of sorbates and sorbents. Sorption intensity of all triazines in native soils was very low (ΔG° ≤ -2 kJ/mol) despite relatively high soil organic carbon content (15 %). Acidification of native soils to pH 4 with hydrochloric acid significantly enhanced sorption intensity of more basic herbicides (atratone and ametryn) and of two most polar atrazine degradation products. Enrichment efficiency of native soils with a cationic surfactant (hexadecyltrimethylammonium) was highly influenced by soil cation exchange capacity. Retention of triazines in organically enriched soils increased significantly with triazine hydrophobicity due to additional hydrophobic interactions. The most intensive sorption of triazines was observed in soils fortified with cationic surfactant in an amount corresponding to 65 % of the native soil cation exchange capacity. Sorption capacity of hydrophobically modified soils was for most triazines greater than the capacity of native and acidified soils. Desorption experiments for each pair of sorbate/sorbent were conducted in a single desorption step. The results indicated partially or almost completely irreversible sorption of most sorbates in soils richer in organic carbon, save for polar degradation products, whose sorption was irreversible to a greater extent in acidified soils. Native Mediterranean soil seems to make no use as a permeable and stabile native barrier for hydrophobic pollutants to reach groundwater. Its acidification and organic carbon enrichment however show a promising potential in preventing water supplies pollution with triazine herbicide residues. [1] Stipiĉević, S., Fingler, S. and Drevenkar, V., Arh. Hig. Rada Toksikol. 60, 43-52 (2009).

U radu je predložen postupak direktne sinteze organobentonita u otpadnoj vodi (heksadecilamonijevim kationima) i sorpcije anionskog bojila (Fatusol orange 85 LD) na dobiveni organobentonit. U otpadnoj vodi kationski surfaktant direktno se "troši" za pripravu organobentonita a dobiveni organobentonit odmah je dostupan za sorpciju anionskog bojila. Ispitani jednostupanjski proces obrade je učinkovit postupak uklanjanja organskih polutanata iz otpadnih voda posebno iz proizvodnje papira, tekstila, bojila i pigmenata u kojima kationski surfaktanti često koegzistiraju s bojilima.

The hexadecyltrimethylammonium (HDTMA) bromide was used to modify the surface of natural zeolitized tuff (NZ) from partial monolayer to the bilayer coverage. The modification of NZ resulted in the change of zeta potential of the surface from negative to positive which enhanced the phosphate (P) adsorption capacity. Only in reactors containing the partial monolayer coverage of the surfactant-modified zeolites (SMZs), the P was efficiently removed from wastewater by combined adsorption onto the SMZs and bacterial uptake in the biomass. The SMZs with monolayer, partial bilayer or bilayer coverage showed the bactericidal effect.

The antibacterial effect of commercial zeolite A against the pure culture of phosphate- accumulating bacterium Acinetobacter junii was investigated. The estimated EC50 values of the zeolite for the inhibition of bacterial colony forming units was 0.33-0.37 g/L by investigated initial pH values of 6, 7 and 8. The toxic effect of zeolite is ascribed to the generation of Al (0.38-1.09 x 10-2 g/L) and Si (2.02-2.93 x 10-2 g/L) ionic species during the process of hydrolysis and dissolution of zeolite (leaching of Al, Si and Na). The toxic effect of Al was confirmed in separate experiments, where the aluminum toxicity (in the form of aluminum sulphate) was estimated as EC50 of 3.45-3.89 x 10-4 g/L. These results suggest the importance of controlling the amounts of synthetic zeolites which can be released to different compartments of environment and accumulate there as nondegradable material. Zeolite A may be the important source of Al in influent of the biological wastewater treatment systems, where they can cause unwanted antibacterial effects.

Three types of natural zeolite tuffs of particle size  0.125 mm, originating from Croatia, Turkey and Serbia were examined. The tuff from Croatia consisted of approximately 50% clinoptilolite, subordinate plagioclase feldspars and quartz (10-15% of each) and traces of K-feldspars and celadonite (app. 5% of each). The tuff from Turkey contained approximately 70% clinoptilolite, subordinate opal-CT and quartz (10– 15% of each) and traces of K-feldspars and biotite (app. 5% of each). The tuff from Serbia contained approximately 75% clinoptilolite and several minor constituents were analcime, calcite, plagioclase feldspars, biotite and quartz (app. 5% of each). The tuff from Serbia had the largest cation exchange capacity of 1.71 meq/g, followed by tuff from Croatia with 1.60 meq/g and tuff from Turkey with 1.35 meq/g. The main exchangeable cation in samples of tuffs from Turkey and Serbia was Ca, whereas Na was the main exchangeable cation in the sample of tuff from Croatia. The particles of the tuff from Croatia had the most negative zeta potential of -25.14 mV, followed by tuff from Turkey (-23.12 mV) and tuff form Serbia (-17.60 mV). The phosphate adsorption capacity varied from 22.5 mg P/kg for Serbian tuff, to 30.2 mg P/kg for Croatian tuff and 77.5 mg P/kg for Turkish tuff. The interaction of zeolite tuffs and phosphate-accumulating bacterium Acinetobacter junii in simulated wastewater was investigated. After 24h of contact with minerals, most of the bacterial population was immobilized onto minerals by adsorptive growth, while the rest of the bacteria remained as planktonic cells in supernatant. The highest number of immobilized cells was obtained on the tuff from Turkey (74.91x108 CFU/g), followed by tuff form Croatia (48.39x108 CFU/g), while the tuff from Serbia had the lowest number of immobilized cells (6.14x108 CFU/g). The zeta potential of A. junii (-18.4 mV) was negative, as well as the zeta potential of mineral particles and no correlation with the number of immobilized cells and zeta potential of minerals was obtained. The best bacterial activity measured as phosphate uptake rate per CFU was obtained with tuff from Croatia, followed by tuff from Turkey and tuff from Serbia. As the result of bacterial activity, the final percent of phosphate removal from wastewater decreased in the order: 50.23%, 46.32% and 40.21% for tuff from Croatia, Turkey and Serbia, respectively. It can be concluded that zeolite tuff can be a good carrier of phosphate-accumulating bacteria. The zeta potential of zeolite tuff was not a crucial factor which determined the immobilization of bacteria. The clinoptilolite content in the zeolite tuff was not the prevailing factor for the immobilization of bacteria. Bacterial immobilization on the zeolite tuff was defined by the original structure of material. The extent of bacterial immobilization on single zeolite tuff cannot be predicted by mineralogical and chemical analysis of mineral, its cation exchange capacity or its zeta potential. The phosphate- accumulating bacteria immobilized onto zeolite tuff as a biocarrier can find application in the bioaugmentation of activated sludge in order to achieve better phosphate removal from wastewater.

The paper investigates the possibility of ammonia sorption from air by using natural zeolite (clinoptilolite) from sedimentary ore from the area of Donje Jesenje, Krapina, Croatia. Ammonia sorption on unmodified and modified zeolite samples was established at different initial concentrations of NH3. Natural exchanger was activated with NaCl, KCl, CaCl2 and MgCl2 salts solutions, treatment with HCl acid and NaOH base and was thermally activated at different temperatures. Results have shown that the acid-modified zeolite sample exhibited much better ammonia sorption capacity compared to natural zeolite. Acid treatment of zeolite increased its specific area and micropore volume, which were reduced by the basic and thermal treatments. Among the Na-form, K-form, Ca-form and Mg-form of zeolite, the best ammonia sorption was achieved with Ca- and Mg-forms.

Ispitana je adsorpcija kvaternog amonijevog tenzida ; heksadeciltrimetilamonijevog (HDTMA) bromida na sintetski zeolit mordenit. Ispitano je i bistrenje sintetske otpadne vode tenzidom modificiranim uzorcima zeolita. Sintetska otpadna voda pripremljena je s ink-jet bojilom uz dodatak organskog otapala. Za karakterizaciju tenzida na zeolitnoj površini, korištene su FT infracrvena spektroskopija tehnikama prigušene ukupne refleksije (attenuated total reflection, ATR) i KBr pastile te FT Ramanova spektroskopija. Dok FTIR spektri upućuju na adsorpciju HDTMA molekula s lancima većinom u gauche konformaciji, ATR i FT Ramanove spektre mordenita modificiranog s HDTMA nije bilo moguće snimiti. Organski kation izmjenjuje se s anorganskim Na+ kationom u unutarnjim i vanjskim površinama zeolita. Posljedica modifikacije je promjena površinskog svojstva zeolita – površina se mijenja iz hidrofilne u hidrofobniju. S 0, 5 % (w/w) tenzidom modificiranih uzoraka zeolita, iz otopine bojila s koncentracijom 20 mg/l djelotvornost obezbojenja veća je od 95 %.

Depending on the type of zeolite, different interactions between material and examined PAB A. junii were observed. Natural clinoptilolite tuff is excellent bacterial carrier and the main mechanism of interaction is immobilization of bacteria onto the surface of material and increase of the total bacterial biomass concentration. In spite, the synthetic zeolites display the toxic effect against the same PAB. Future investigations should be done in order to investigate the influence of different types of zeolite on other bacteria.

The aim of this study was to determine the potential of phosphate (P) removal from wastewater by P-accumulating bacteria and organic bentonite. Organic bentonite was prepared by treating bentonite clay with quaternary ammonium salt – cetyltrimetylammonium (CTA) bromide. Cation exchange capacity (CEC) of the bentonite was found to be 179.0 meq/100 g of the dry bentonite. The CTA occupied ca. 175% of the CEC. The modification of bentonite with CTA in amounts higher than 55% of the CEC resulted in the change of zeta potential of particles from negative to positive. Only in reactors containing organic bentonite samples occupied with 3.5 and 28% of the CEC the P was efficiently removed from wastewater by combined adsorption and bacterial uptake in the biomass. The organic bentonite samples with higher CTA loading (from 55 to 175% of the CEC) showed the bactericidal effect. To enhance the P removal from wastewater in the aerated biological system, the organic bentonite can be used, but the special attention should be given to the configuration and location of sorbed CTA molecules and its potential desorption.

Na saniranom odlagalištu otpada Jakuševec u Zagrebu procjedne vode deponije se prikupljaju pomoću drenažnog sustava u dva sabirna bazena. Recirkulacijom procjedne vode kroz tijelo deponija i evaporacijom vrši se redukcija količine vode dok bi se ostatak trebao pročistiti prije ispuštanja u Savu. Do danas je prezentirano nekoliko idejnih rješenja pročišćavanja procjedne vode ali iz tehničkih razloga nisu primjenjivana in situ. U ovom radu prikazana je mogućnost pročišćavanja procjedne vode aeracijom i dodatkom prirodnih tufova. Primjenom aeracije i dodatkom klinoptilolitnog i montmorilonitnog tufa u sirovu procjednu vodu nije postignuto značajno pročišćavanje zbog manjka fosfata u vodi koji je nužan za ostvarenje biološkog pročišćavanja. Nakon dodatka fosfata u procjednu vodu samom aeracijom je postignuto značajno biološko pročišćavanje, koje je dodatno povećano dodatkom klinoptilolitnog tufa. Pri tome je amonijak, koji je glavni polutant procjedne vode u ovom slučaju, smanjen za 67% u vodi iz drenažnog kanala i za 88% u vodi iz retencionog bazena procesima biološke nitrifikacije i uzimanjem u biomasu autohtonih bakterija. Na osnovu postignutih rezultata može se zaključiti da se dodatkom fosfata i prirodnog klinoptilolitnog tufa u procjednu vodu te primjenom aeracije može postići zadovoljavajuće biološko pročišćavanje. Predstavljena metoda samoočišćenja procjedne vode mogla bi biti izvediva s tehničkog gledišta i ekonomski isplativa.

Premda postoji tendencija smanjivanja mase svih vrsta otpada postupcima naprednih tehnologija recikliranja, ipak će deponije morati prihvatiti, teško razgradivi ili toksični otpad koji se ne može reciklirati bez opasnosti za okoliš. Takav otpad mora biti trajno izoliran u tijelu deponije višeslojnim fleksibilnim sintetskim ili prirodnim mineralnim barijerama, uz najmanju moguću emisiju deponijskih eluata u tlo i podzemne vode. Poznavajući geomehanička i fizikalno-kemijska svojstva predloženih materijala (posebno minerala glina i HEU-tipova zeolita i njihovih modificiranih oblika), mogu se modelirati sustavi smjesa s obzirom na sorpcijske, ionsko-izmjenjivačke i hidrauličke karakteristike kakve se pretpostavljaju za fleksibilne multimineralne višeslojne deponijske barijere.Temeljem proračuna iz poznate mase procjednih voda i masenog udjela kontaminanata raspoloživih za sorpciju na zbijene multimineralne barijere, pokazano je da je debljina od 0, 1 m za pojedinačni reaktivni sloj dovoljna za fiksaciju ukupne mase kontaminanata iz tijela sanitarne deponije. Predložena je shema fleksibilne reaktivne zbijene višeslojne bentonitno-zeolitne barijere, koju čini: a) drenažni sloj (granulirani materijal bez minerala kalcita i dolomita), b) zaštitni sloj geomembrane HDPE (kvarcni pijesak ili dijatomejska zemlja), c) geomembrana HDPE (ili neka druga polimerna sintetska membrana visoke gustoće), d) makroporna organofilna i hidrofobna fleksibilna deponijska barijera (HDTMA-modificirani filosilikati i zeolitni tufovi i silikonizirane mineralne vrste), e) bentonitno-zeolitni brtveni kationsko-izmjenjivački sloj, f) brtveni sloj smjese Ca-bentonita i Na- bentonita, g) brtveni sloj smjese ne- ekspanzivnih minerala glina (kaolinit, illit).

In this work the sorption of the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA+Br-) on a natural zeolite clinoptilolite was studied. Clarification of artificial wastewater (AWW) by the surfactant-modified zeolite samples was examined too. Artificial wastewater was prepared with ink-jet dye with addition of organic solvent. The results indicated that the examined surfactant can be significantly sorbed by zeolite. Zeta-potential measurements showed that the surfactant uptake resulted in a reversal of the charge on the zeolite from negative to positive. This is acchieved when surfactant loading on zeolite is approximately equal 0, 145 mmol/g and in this point the zeolite charge is about zero. Untreated zeolite showed little affinity for wastewater clarification. For the wastewater clarification the most efficient are zeolite samples in which surfactant loading was from 0, 022 to 0, 125 mmol/g. With 0, 5 % (w/w) of these surfactant-modified zeolite samples, from the solution with dye concentration of 20 mg/l efficency of clarification is more than 95%.