589 research outputs found
The Ending of the Provincial Service of Tomislav Šagi in Theillyrian Capuchin Province and Its Heritage Throughout History
No full textRad se bavi istraživanjem, prikazom i osvjetljavanjem dosad neistraženog djelovanja i aktivnosti koje je kao provincijal dvojezične i dvonacionalne, hrvatsko-slovenske, Ilirske kapucinske provincije imao tada mladi profesor i intelektualac Tomislav Šagi zadnjih mjeseci svoje provincijalne službe, koja je započela u srpnju 1955., a završila u srpnju 1958. godine. U ovom radu ograničavamo se na završno razdoblje njegove provincijalne službe, od siječnja 1958. godine pa do kraja iste godine budući da smo u prethodnim dvama znanstvenim radovima o tome već pisali. U jednom radu bavili smo se njegovim putom do izbora za provincijala, a u drugom radu smo se bavili samom provincijalnom službom od njegova izbora pa sve do kraja 1957. godine. Ovim radom nastavljamo tamo gdje smo u prethodnim radovima stali. U ovom radu, nakon vrlo kratkog osvrta na povijesni kontekst u kojem se odvijalo njegovo djelovanje koje je predmet našeg rada, istražit ćemo i prikazati ono što je prethodilo provincijalnom kapitulu, njegove pripreme, odvijanje, a zatim ćemo obratiti pažnju i na profesorski rad Tomislava Šagija na Katoličkome bogoslovnom fakultetu Sveučilišta u Zagrebu te na stalne prateće poteškoće u provinciji. U zadnjem dijelu ovoga rada ukazat ćemo na organizacijsko-pravnu baštinu koju je Tomislav Šagi kao provincijal ostavio tada Ilirskoj kapucinskoj provinciji, a koja je kasnije postala i ostala integrirani dio organizacijsko-pravne baštine Hrvatske kapucinske provincije sv. Leopolda Bogdana Mandića.This study delivers analysis and description of the activities of Tomislav Šagi (Tomislav Janko Šagi-Bunić) during the last months of his service as the provincial in the Illyrian Capuchin province. Namely, the study covers only the period between January 1958 and December 1958, since, in the two previous studies, the author has analyzed earlier periods of Šagi’s service (from July 1955 to December 1957). In this study, the author has tried to reveal and describe events that preceded the Provincial Chapter of July 1958. Besides these events, the author describes Šagi’s work at the Catholic Faculty of Theology of the University of Zagreb. In the concluding part of the article, the author emphasizes Šagi’s organizational and legal heritage in the Illyrian Capuchin province that later became part of the Croatian Capuchin province of St. Leopold Bogdan Mandić. Therefore, this article – together with the previous two studies – represents a contribution to our knowledge about the early days of service of Tomislav Šagi, which was up to now little known in the wider community
Grinding away plastic waste: enabling the circular economy of plastics
No full textSingle-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or is being incinerated in a highly unsustainable manner. Plastic waste in the environment endangers ecosystems, and microplastics in babies raise alarming health concerns. Hence, one of the global priorities is circular economy for plastics which does not further exploit fossil fuel feedstocks. However, current technologies like mechanical recycling are inadequate, and innovative ones such as chemical recycling, i.e., converting plastics back to the starting monomers, are essential. For example, we can use the recycled monomers to make new plastics in a circular manner or upcycle them to other value-added functional materials. Here, I will present a sustainable technology we developed for the chemical recycling of polyethylene terephthalate (PET). PET represents 10% of global plastic production and dominates in plastic packaging. The technology relies on mechanochemistry (grinding) which uses mechanical action for the chemical breakdown of plastic polymers in an environmentally friendly way. The next step in our research is to use life cycle and techno-economic assessment to validate the sustainability and commercial viability of our technology with the goal of transferring it to real-world industrial application
Thermo mechanochemistry: merging heat and force for discovering new chemical transformations
No full textMechanochemistry is a hot topic in chemistry, and the number of researchers from academia and industry joining the field is growing. Mechanical action drives chemical reactions forward independently of the solubility of reactants and drastically minimises solvent usage and waste production. Mechanochemistry also provides other advantages, such as faster reaction times, higher yields, altered selectivity, and access to products not obtainable by other methods. Furthermore, recent innovations in mechanochemistry enable conducting chemical reactions by combining force and heat in approach called thermo-mechanochemistry [1]. These conditions typically overcome high activation energies and access products not obtainable by mechanochemistry at ambient temperature conditions. In this talk, I will give an overview to this emerging topic and to our discoveries by thermo-mechanochemistry that include prebiotic peptide bond formation [2], synthesis of amide-based active pharmaceutical ingredient [3], condensation of diamondoid derivatives [4], and manipulation of polymorphic transition temperatures in organic molecular crystals [5]
Breaking the wall of circular plastics economy
No full textTraditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions
Mechanochemical conversion of polyethylene terephthalate into valuable metal-organic frameworks
No full textSingle-use plastics are causing plastic pollution, and less than 10% of plastic waste is recycled globally. Here, we present a sustainable mechanochemical1 protocol for converting post-consumer polyethylene terephthalate (PET) textile and bottles into the porous metal-organic framework (MOF) UiO-66. We used time-resolved in situ synchrotron powder X-ray diffraction and Raman spectroscopy to monitor the depolymerization of PET during ball milling with sodium and potassium hydroxide and water as a liquid additive (Figure 1). For synthesizing UiO-66, we focused on the better performing sodium hydroxide and optimized two distinct synthetic routes to produce high-quality UiO-66. Our results demonstrate the potential of mechanochemistry to enable more circular MOF synthesis using post-consumer PET waste
Breaking the wall of circular plastics economy
No full textTraditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions
Sustainable mechanochemical reaction engineering: from molecular mechanisms to scalable technology
No full textIn this talk, I will present about our quest to fundamentally understand mechanochemical reactions by in situ monitoring studies. Another of our interest is scaling up mechanochemistry. For example, we are now working on developing mechanochemical technology to enable a circular economy of plastics
Mechanochemistry: fundamentals to application
No full textIn the first part, I will talk about the role of mechanochemistry in prebiotic chemistry. For example, prebiotically plausible pathways to peptides from inactivated amino acids are unclear as most oligomerization approaches rely on thermodynamically disfavored reactions in solution. I will show how a combination of mineral surfaces and mechanochemical activation enables the oligomerization of amino acids to oligopeptides (Figure 1). In the second part, I will show how fundamental studies inspired to use mechanochemistry for the sustainable synthesis of commercially relevant compounds, in line with the United Nations Sustainable Development Goals.2 We developed a solvent-free thermo-mechanochemical approach for the direct coupling of carboxylic acids and amines, which avoids activators and additives. We applied our methodology for the quantitative synthesis of the active pharmaceutical ingredient moclobemide (Figure 2)
Waste to value: upcycling PET bottles into MOFs using mechanochemistry
No full textSingle-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or gets incinerated in a highly unsustainable manner. Here, I will present a sustainable mechanochemical protocol for the chemical upcycling of waste polyethylene terephthalate (PET) bottles to porous UiO-66 metal-organic framework (MOF). We used in situ and ex situ characterization to gain a deep understanding of the underlying mechanochemical process leading to high crystallinity and -porosity UiO-66. Our results show the potential of mechanochemistry for the sustainable production of high-quality value-added materials such as UiO-66 from waste PET bottles
Upcycling waste PET bottles to porous UiO-66 by mechanochemistry
No full textSingle-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or gets incinerated in a highly unsustainable manner. Here, I will present a sustainable mechanochemical protocol for the chemical upcycling of polyethylene terephthalate (PET) to porous UiO-66 metal-organic framework (MOF). In the first step, PET is ball-milled with sodium hydroxide and undergoes alkaline hydrolysis to disodium terephthalate (Na2TP). Time-resolved in situ monitoring of ball milling reaction by synchrotron powder X-ray diffraction shows the appearance of crystalline Na2TP after 20 min of milling. However, ex-situ analysis at different milling times by gel permeation chromatography reveals that the depolymerisation step needs more milling for completion. After two hours of ball milling, there are only trace amounts of leftover PET. For upcycling to UiO-66, a zirconium acetate cluster is added to Na2TP together with liquid additives and after milling fo
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