10 results on '"Sežun, Mija"'
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2. Chemical and enzymatic deinking efficiency of agricultural and industrial waste fiber-based paper packaging.
- Author
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Sežun, Mija, Karlovits, Igor, and Kavčič, Urška
- Subjects
- *
WASTE paper , *INDUSTRIAL wastes , *AGRICULTURAL wastes , *INDUSTRIAL efficiency , *PACKAGING materials , *MANUFACTURING processes , *PACKAGING recycling - Abstract
BACKGROUND: Deinking is an important part of paper recycling that involves the removal of ink particles from the paper fibres. This industrial process is important so that the fibres can be recirculated back into paper production, which enables better sustainability as fewer fresh fibres are needed. In this study, we examined five different alternative fibre materials from different agricultural residues and industrial processes for the pilot production of papers. Papers containing fibres from invasive plants (Japanese knotweed), dedicated crops (miscanthus, acacia), agricultural residues (tomato stems), and industrial waste (jute - fibres from coffee bags) were printed with water-based flexo inks and deinked with two separate processes (chemical and enzymes). Mechanical (break and tensile index, breaking length) and optical properties (ISO whiteness, brightness and CIE L*a*b* values) were measured and ink elimination IR700 and deinking efficiency was calculated for the two deinking processes. RESULTS: Enzymatic treatment improved the mechanical properties of deinked pulp in comparison with the classic chemical treatment. Mechanical strength for almost all papers increased slightly (breaking length up to 20% in tomato and jute), and the optical result (brightness) increased similarly for both processes due to the bleaching action of the colour-shaded samples, whereas the deinking efficiency showed mixed results between chemical- and enzyme-type deinking (with chemical achieving better elimination measured at 700 nm) in the typical range of ink elimination values (15-35%) for flexographic inks. This indicates further optimization of the deinking with enzymes is needed due to different alternative fibre compositions and variations of residues in the delignification processes. CONCLUSION: Using a combination of adjusted enzymatic treatment as a precursor for deinking of paper-based packaging materials sourced from alternative fibres showed promising results regarding mechanical properties, whereas the optical properties need to be improved with cellulase optimization or by using mixes of different enzymes. These kinds of paper materials printed with flexo inks were found to be successfully deinkable with the chemical ISO-based deinking protocol. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. REMOVAL INK EFFICIENCY OF FLEXOGRAPHIC PRINTED PAPER PACKAGING MADE FROM DIFFERENT ALTERNATIVE PLANTS
- Author
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Sežun, Mija, Karlovits, Igor, and Kavčič, Urška
- Abstract
m
- Published
- 2021
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4. CROP RESIDUES AS FIBROUS AND FUNCTIONAL COMPOUNDS FOR PAPER PRODUCTION
- Author
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Osojnik Črnivec, Ilja Gasan, Sežun, Mija, Skrt, Mihaela, Kapin, Tea, and Poklar Ulrih, Nataša
- Subjects
crop residues, vegetable residues, bioactive compounds, paper production - Abstract
Due to the high lignocellulose content, as well as the high content of phenolic compounds, agro-industrial vegetable waste is well suited for valorization in packaging materials. As specialized packing materials, these materials may offer competitive advantages to paper producers, utilizing a low cost feedstock to produce a bespoke product of good quality. In our contribution, we focus on the production residues of various plant streams (e.g. growing and processing of onions, olives and pomegranates), to demonstrate how such diverse agro-industrial bio-waste materials could be fully exploited even before their reformulation. Onion skins and olive leaves both showed high antioxidant activity and the possibility to recover relatively high yields of bioactive compounds (roughly 100 mg of quercetin or oleuropein per g of dry extract). However, in pomegranate peel, the content of the antocyanins (roughly 0.3 mg of antocyanins per g of dry extract) was low. All three plant residues sources produced unique paper materials. Olive skins and olive leaves were used as two individual feedstocks, whereas the pomegranate peel was required to be added to cellulose. The resulting papers exhibited good technological properties, as well as interesting texture and appearance and might as such be suited for the production of special papers. The determined characteristics of the samples demonstrate a good potential for cascading use where paper production should be further studied following the extraction of bioactive components.
- Published
- 2021
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5. Extraction of Polyphenols and Valorization of Fibers from Istrian-Grown Pomegranate (Punica granatum L.).
- Author
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Skrt, Mihaela, Albreht, Alen, Vovk, Irena, Constantin, Oana Emilia, Râpeanu, Gabriela, Sežun, Mija, Osojnik Črnivec, Ilja Gasan, Zalar, Uroš, and Poklar Ulrih, Nataša
- Abstract
Pomegranate fruit is an ancient fruit that is used not only because of its deep-red color and tasty arils but also due to the health benefits of its extracts. Pomegranate is a valuable source of bioactive compounds, including colorful anthocyanins and other polyphenols. The main objective of the present study was to gain comprehensive knowledge of the phenolic composition and antioxidative activity of a new pomegranate cultivar, grown in Northwest Istria, a part of the North Adriatic coastal area. Various parts of the pomegranate fruit parts were extracted in 70% ethanol or water. Total phenolic content and antioxidative capacity were respectively determined with Folin–Ciocalteu reagent and ABTS radical. Phenolics were examined and analyzed with TLC, LC-MS, and HPLC. Pomegranate juice was prepared from red arils and after thermal treatment, the stability of anthocyanins was monitored for several months to understand the effect of storage. The highest total phenolics were determined in ethanol pomegranate peel extracts (30.5 ± 0.6 mg GAE/g DM), and water peel extracts exhibited the highest antioxidative activity (128 ± 2 µg TE/g DM). After five months of storage of thermally treated pomegranate juice, 50–60 percentage points increase in anthocyanin degradation was observed. Pomegranate peel was further tested as a sustainable inedible food source for papermaking. Due to the low content of cellulose and the high percentage of extractives, as well as a distinguished texture and appearance, the paper made from pomegranate peel is best suited for the production of specialty papers, making it particularly interesting for bioactives recovery, followed by material restructuring. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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6. Cavitation as a potential technology for wastewater management
- Author
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Sežun, Mija, Kosel, Janez, Zupanc, Mojca, Hočevar, Marko, Vrtovšek, Janez, Petkovšek, Martin, and Dular, Matevž
- Subjects
udc:532.528(045) ,hranila ,nutrients ,razgradnja muljev ,hydrodynamic cavitation ,odpadni biološki mulj ,paper mill plants ,hidrodinamska kavitacija ,obdelala odpadnih voda ,secondary sludge ,papirna industrija - Abstract
Wastewater recycling and sludge removal in the paper industry account for about 60 % of all process costs. New and environmentally friendly wastewater treatment techniques are, therefore, continually being developed. Cavitation exploitation is currently a well-investigated topic that is also interesting for the paper production industry. This study investigates efficiency of hydrodynamic cavitation alone and in combination with the addition of NaOH for the treatment of secondary pulp and paper mill sludge in order to enhance nutrient release. First, two laboratory-scale devices were tested: the blow-through and the rotating hydrodynamic cavitation generator. The latter set-up proved to be more efficient: therefore, further experiments were performed on its pilot-scale version. The results showed an increase of soluble chemical oxygen demand (CODs) by 514 mg/L, total nitrogen (Nt) by 17.4 mg/L, and total phosphorous (Pt) by 2.3 mg/L. To further increase nutrient release combination of cavitation and sludge sample alkalinization was tested. The addition of NaOH and 30 min cavitation of secondary sludge (500 L) significantly improved CODs and Nt release by 2400 mg/L and 120 mg/L, respectively. Microbiological photos revealed a definite disintegration of sludge flocks. According to our estimates, 1.9 kg of released CODs from alkaline pre-treated and cavitated sludge would cost only one euro.
- Published
- 2020
7. BIODEGRADABILITY AND COMPOSTING OF PACKAGING MADE FROM INVASIVE PLANT BASED MATERIALS
- Author
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Sežun, Mija, Karlovits Igor, Daša Medvešček, and Urška Kavčič
- Subjects
lignocellulosic material ,packaging ,biodegradability, ,compostability ,alien plant species - Abstract
Packaging has many useful properties throughout its life cycle. It is used to protect against injuries, contamination and tempering. However, we know that each packaging after its use becomes waste. There are many pathways that we are meeting at the end packaging life cycle. Some have minor and some major environmental impacts. The main impact is how the packaging will be disposed, other environmental impacts depend on the choice of material, eco design and local waste management facilities. In practice we know different ways to remove packaging: reuse, recycle, compost, incineration and landfilling. However, we must be aware that the disposal is unacceptable, the landfills are closing and the negative environmental impacts are high. Composting and recycling have their own requirements, packaging must be biodegradable and must not contain interfering substances. Requirements are determined within the environmental registration and must be taken into account during implementation. In our study, we will present the benefits of using alternative sources and show environmental acceptability. Environmental acceptability will be determined on the basis of compost and recycling test. The study will include paper from the Solidago species, Acacia and Fallopia japanese plants. These plants have good characteristics for paper and cardboard production. In the future, the presence of alternative varieties of lignocellulosic biomass will be a major contribution for paper and packaging industry. 
- Published
- 2019
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8. Cavitation as a Potential Technology for Wastewater Management - An Example of Enhanced Nutrient Release from Secondary Pulp and Paper Mill Sludge.
- Author
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Sežun, Mija, Kosel, Janez, Zupanc, Mojca, Hočevar, Marko, Vrtovšek, Janez, Petkovšek, Martin, and Dular, Matevž
- Subjects
- *
SEWAGE purification , *PAPER mills , *PULP mills , *PAPER pulp , *CAVITATION - Abstract
Wastewater recycling and sludge removal in the paper industry account for about 60% of all process costs. New and environmentally friendly wastewater treatment techniques are, therefore, continually being developed. Cavitation exploitation is currently a well-investigated topic that is also interesting for the paper production industry. This study investigates efficiency of hydrodynamic cavitation alone and in combination with the addition of NaOH for the treatment of secondary pulp and paper mill sludge in order to enhance nutrient release. First, two laboratoryscale devices were tested: the blow-through and the rotating hydrodynamic cavitation generator. The latter set-up proved to be more efficient: therefore, further experiments were performed on its pilot-scale version. The results showed an increase of soluble chemical oxygen demand (CODs) by 514 mg/L, total nitrogen (Nt) by 17.4 mg/L, and total phosphorous (Pt) by 2.3 mg/L. To further increase nutrient release combination of cavitation and sludge sample alkalinization was tested. The addition of NaOH and 30 min cavitation of secondary sludge (500 L) significantly improved CODs and Nt release by 2400 mg/L and 120 mg/L, respectively. Microbiological photos revealed a definite disintegration of sludge flocks. According to our estimates, 1.9 kg of released CODs from alkaline pre-treated and cavitated sludge would cost only one euro. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
9. Hydrolytic and oxidative enzyme production through cultivation of Pleurotus ostreatus on pulp and paper industry wastes.
- Author
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Skočaj, Matej, Gregori, Andrej, Grundner, Maja, Sepčić, Kristina, and Sežun, Mija
- Subjects
CELLULASE ,ENZYMES ,LIPASES ,PAPER ,PLEUROTUS ostreatus ,PEROXIDASE ,XYLANASES - Abstract
The growth of oyster mushroom (Pleurotus ostreatus) on pulp and paper industry wastes was studied. Specifically, the question was investigated whether solid-state fermentation of P. ostreatus on paper-mill deinking sludge and primary sludge substrates is appropriate for production of enzymes, relevant to the pulp and paper industry. Following fermentation, extracellular protein was extracted and the specific activities of four enzymes were determined, namely, the cellulase, xylanase, lipase and peroxidase. Furthermore, the effects of the pH of the extraction buffer on these enzyme activities were determined, along with the effects of the incubation time. The data show that P. ostreatus can grow on solid wastes from the pulp and paper industry, which could help to minimize the waste volume and to decrease the ecological impact. Furthermore, the solid wastes in focus are good substrates for the production of commercially interesting enzymes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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10. Anaerobic Digestion of Brewery Spent Grain in a Semi-Continuous Bioreactor: Inhibition by Phenolic Degradation Products.
- Author
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Sežun, Mija, Grilc, Viktor, Zupančič, Gregor D., and Logar, Romana Marinšek
- Subjects
- *
ANAEROBIC digestion , *BIOREACTORS , *GRAIN , *PHENOLS , *BIODEGRADATION , *LIGNOCELLULOSE , *BIOGAS production , *CRESOL , *INTERMEDIATES (Chemistry) , *MIXTURES - Abstract
In this study anaerobic digestion of selected lignocellulosic substrate, namely brewery spent grain (BSG), was studied In order to facilitate anaerobic digestion several types of pretreatment methods were tested such as: mechanical, chemical (alkali and acid) and thermo-chemical. The anaerobic digestion experiments were carried out in a semi-continuous stirred bioreactors with the organic loading rates between 2.9 and 3.9 kgCODm-3d-1 (1.9 and 2.5 kgVSS m-3d-1 respectively) and corresponding hydraulic retention times of 33-39 days. Biogas production and composition, pH, COD, TSS and VSS, short chain fatty acids and phenolic compounds were measured. A significant inhibition of biogas production occurred, depending on the type of substrate pretreatment. There are indications that p-cresol is responsible for process inhibition when its concentration in the reaction mixture exceeds critical value between 115 and 240 mg L . Anaerobic digestion of chemically pretreated BSG (acid and alkali) and untreated-raw BSG was inhibited between the days 56 and 63 of the experiment, followed by thermo-chemically pretreated BSG on day 112 and mechanically pretreated BSG on day 126. Analyses of the substrates showed no phenolic compounds either in raw-untreated BSG or pretreated substrates, therefore the recorded p-cresol is an intermediate degradation product, responsible for process inhibition. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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