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Abstract: The pandemic of COVID-19 disease has brought many challenges in the field of personal protective equipment. The amount of disposable surgical masks (DSMs) consumed increased dramatically, and much of it was improperly disposed of, i.e., it entered the environment. For this reason, it is crucial to accurately analyze the waste and identify all the hazards it poses. Therefore, in the present work, a DSM was disassembled, and gravimetric analysis of representative DSM waste was performed, along with detailed infrared spectroscopy of the individual parts and in-depth analysis of the waste. Due to the potential water contamination by micro/nanoplastics and also by other harmful components of DSMs generated during the leaching and photodegradation process, the xenon test and toxicity characteristic leaching procedure were used to analyze and evaluate the leaching of micro/nanoplastics. Micro/nanoplastic particles were leached from all five components of the mask in an aqueous medium. Exposed to natural conditions, a DSM loses up to 30% of its mass in just 1 month, while micro/nanoplastic particles are formed by the process of photodegradation. Improperly treated DSMs pose a potential hazardous risk to the environment due to the release of micro/nanoparticles and chloride ion content.
Keywords: DSM, micro/nanoparticles, leaching, artificial weathering, environmental pollution
Published in DKUM: 26.03.2025; Views: 0; Downloads: 1
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Abstract: Since millions of tons of packaging material cannot be recycled in conventional ways, most of it ends up in landfills or even dumped into the natural environment. The researched methods of chemical depolymerization therefore open a new perspective for the recycling of various PET materials, which are especially important for packaging. Food preservative packaging materials made from PET plastics are complex, and their wastes are often contaminated, so there are no sophisticated solutions for them in the recycling industry. After integrating the biopolymer chitosan, which is derived from natural chitin, as an active surface additive in PET materials, we discovered that it not only enriches the packaging material as a microbial inhibitor to reduce the bacteria Staphylococcus aureus and Escherichia coli, thus extending the shelf life of the contained food, but also enables economical chemical recycling by alkaline or neutral hydrolysis, which is an environmentally friendly process. Alkaline hydrolysis at a high temperature and pressure completely depolymerizes chitosan-coated PET packaging materials into pure terephthalic acid and charcoal. The products were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The resulting reusable material represents raw materials in chemical, plastic, textile, and other industries, in addition to the antimicrobial function and recyclability itself.
Keywords: chitosan, active packaging, PET, recycling, reusability
Published in DKUM: 26.03.2025; Views: 0; Downloads: 5
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Abstract: Proizvodnja osebne varovalne opreme (OVO) v zadnjih letih izredno hitro narašča. K tej rasti je zagotovo prispevala pandemija bolezni COVID-19, ki pa ni edini razlog za izredno hitro rast tega sektorja. Po podatkih številnih analitičnih hiš bo trg OVO do leta 2028 imel več kot 60 % rast v primerjavi z letom 2020. Z večanjem proizvodnje OVO, pa se večajo tudi količine tega tipa odpadka in s tem pritisk na prevzemnike odpadkov. Glede na to, da gre pri zaščitnih kirurških maskah (ZKM), za enega najbolj razširjenih kosov OVO, ki ima izredno kratek čas uporabe in je njegova življenjska pot izredno linearno naravnana, so v tej doktorski disertaciji bili analizirani vplivi tega kosa OVO na okolje in predstavljene možnosti recikliranja tega materiala v večvrednostne materiale. Opravljena je bila raziskava rokovanja Slovencev z ZKM v kateri je bilo ugotovljeno, da je v prvem letu pandemije v Sloveniji bilo uporabljenih več kot 344 milijonov kosov ZKM. Prav tako je bila opravljena ocena odpadka in ocena vpliva ZKM na okolje, kadar so te nepravilno odložene. Dokazano je bilo, da so materiali zastopani v ZKM izredno primerni za postopke mehanskega recikliranja. Z namenom zagotavljanja večvrednosti končnega reciklata, so reciklatu ZKM bila dodana naravna polnila. Izbrana so bila polnila na osnovi celuloze in hitozana, saj gre za najbolj razširjena naravna polimera. Med polnili na osnovi celuloze so bili uporabljeni celulozni nanokristali, celulozne nanofibrile in kvaternizirane celulozne nanofibrile, med tem ko sta med hitozani bila uporabljena hitozan z nizko molekulsko maso in kvaterniziran hitozan. Večina polnil, je izkazala pozitiven vpliv na mehanske lastnosti reciklata, saj so nekatera povečala elastičnost reciklata tudi do 100%. Izvedene so bile številne analize površine. Te analize so med drugim pokazale, da prisotnost vseh polnil izkazuje dvig hidrofobnosti materiala, obe kvaternizirani polnili, pa v prisotnosti več kot 10 % izkazujeta tudi zelo dobro antibakterijsko delovanje reciklata, na gram + bakterije Staphylococcus aureus.
Keywords: zaščitne kirurške maske, mehansko recikliranje, večvrednostno recikliranje, naravna polnila, polimerni kompozit
Published in DKUM: 29.11.2024; Views: 0; Downloads: 56
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Abstract: The production of personal protective equipment (PPE) has increased dramatically in recent years, not only because of the pandemic, but also because of stricter legislation in the field of Employee Protection. The increasing use of PPE, including disposable surgical masks (DSMs), is putting additional pressure on waste collectors. For this reason, it is necessary to find high-quality solutions for this type of waste. Mechanical recycling is still the most common type of recycling, but the recyclates are often classified as low-grade materials. For this reason, a detailed analysis of the recyclates is necessary. These data will help us to improve the properties and find the right end application that will increase the value of the materials. This work represents an extended analysis of the recyclates obtained from DSMs, manufactured from different polymers. Using surface and morphology tests, we have gained insights into the distribution of different polymers in polymer blends and their effects on mechanical and surface properties. It was found that the addition of ear loop material to the PP melt makes the material tougher. In the polymer blends obtained, PP and PA 6 form the surface (affects surface properties), while PU and PET are distributed mainly inside the injection-molded samples.
Keywords: mechanical recycling, disposable surgical mask, morphology, surface properties, mechanical properties, nonwoven materials, PPE
Published in DKUM: 09.04.2024; Views: 232; Downloads: 22
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Abstract: The purpose of this bachelor thesis is to optimize pretreatment of a wastewater from cosmetic industry. The current cleaning process in industry consists of two steps, namely i) AOP (Advanced Oxidation Process), and ii) flocculation/flotation (FF). However, as the HEM (n-Hexane Extractable Materials) decreases the efficiency of the AOP process by heavily blocking the light to penetrate in the wastewater to be cleaned, a first FF in acid environment is introduced in the process as pretreatment. The parameters that were varied to carry out the optimization were i) Fe2(SO4)3 content added in first FF and, ii) H2O2 content. To precise, JAR tests werecarried out to make the FF and the sample was put in a 1.8 L reactor and subjected to UV light in the AOP treatment. For the better distribution of the H2O2 and Fe2(SO4)3 addition to the cleaning process the design of experiment was used. The HEM measured wascarried out according to standard method “United States Environmental Protection Agency (EPA), Method 1664, Revision B: n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry”. We found that the percentage of removal is very high, it goes from 96.3% till more that 99.9%. In average, with this new first FF, the percentage of removal is 98.61% which represents a very high enough removal rate of HEM to achieve the WW disposal limits in most cases. Only 3 out of 9 experiments exceeded the emission limit of 100 mg/L of HEM due to the type of surfactant, which we can conclude it has a strong influence in the removal of HEM.
Keywords: AOP, n-hexane extractable material, wastewater pretreatment, flocculation/flotation
Published in DKUM: 22.10.2021; Views: 852; Downloads: 34
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