Iskanje po katalogu digitalne knjižnice

Opis: Step towards resilience and sustainability through exploring renewable biomass and waste streams to produce higher-added value products and energy is among key aspects for closing the loops, saving resources, and reducing the resource and emission footprints. In that respective, crustacean shells waste can offer rich spectre of valuable compounds such as proteins, chitin, carotenoids. This waste is produced in large quantities worldwide, thus allowing for commercial valorisation. An overview of technologies is undertaken for more sustainable and environmentally friendly chitosan production via chitin isolation and conversion and compared to the conventional processes. Furthermore, an assessment of the environmental burden and energy demand distribution for conventional and more sustainable alternative processes was performed, based on lab-scale experimental data. Three different chitin extraction routes and three distinct chitosan conversion processes were considered and compared for their greenhouse gas footprint, abiotic depletion, acidification, eutrophication and other potentials. Finally, the energy demand distribution was analysed considering electricity production patterns from three European countries, Slovenia, Portugal and Norway. The results showed that alternatives 3-A and 3-B (conventional eco-solvents - conventional deacetylation with 40 % and 50 % NaOH) generate the lowest environmental burden (184 g CO2 eq./g chitosan). Electricity was the main hotspot of the processes, used either for extraction, plasma treatment or deacetylation. The sensitivity analysis proved that the Norwegian electricity mix has the lowest environmental impact (4.2 g CO2 eq./g chitosan). This study highlights the impact of blue biorefineries by transforming marine waste to valuable biopolymers such as chitin and chitosan.
Ključne besede: shrimp shells waste, blue biorefinery, value-added products, chitosan, sustainable production, comparative environmental assessment
Objavljeno v DKUM: 08.01.2025; Ogledov: 1; Prenosov: 3
Celotno besedilo (2,16 MB)

Opis: Japanese knotweed is an invasive alien plant species with characteristic rapid expansion in Europe and North America and resistance to extermination. It displaces autochthonous biodiversity and causes major damage to infrastructure, thus causing global ecological and economic damage. The Japanese knotweed plant is usually eradicated using various chemical, biological, or mechanical techniques, which at a large scale include heavy equipment, usually followed by incineration. Therefore, excavation is preferred to eradication techniques, and as a biomass waste recovery method due to the extraction of high-value biocompounds. This is supported by the fact that the Japanese knotweed possesses various bioactive compounds with beneficial effects on human health. Its rhizome bark extract produces strong and stable antioxidant activity over time, as well as apoptotic, antibacterial, and other beneficial activities. In this work, an environmental impact assessment, including greenhouse gas footprint, acidification, eutrophication, and ecotoxicity for extraction route of the Japanese knotweed rhizome bark, is performed. A comparative case study between the lab-based and proposed pilot-scale production of active added-value extract was evaluated. The results show the pilot-scale production exhibits lower environmental burdens, mainly due to greater electricity requirements for the lab-scale alternative.
Ključne besede: Japanese knotweed rhizome bark extract, invasive alien plant species, bioactive compounds, lab-scale, pilot-scale, life cycle assessment (LCA), environmental burden assessment
Objavljeno v DKUM: 19.03.2024; Ogledov: 236; Prenosov: 20
Celotno besedilo (1,31 MB)
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Opis: Predobdelava je ključna za učinkovito uporabo lignocelulozne biomase za namene proizvodnje biogoriv in biokemikalij. Z njo razklopimo težko razgradljivo ligninsko strukturo in pripomoremo k boljši dostopnosti do celuloze in hemiceluloze v predobdelani biomasi. Raziskali smo, kako različne metode predobdelave vplivajo na vsebnosti izbranih parametrov. Preverjali smo kemijsko potrebo po kisiku (KPK), vsebnosti dušika, fosforja in kalija (NPK), NH3, celotnega organskega ogljika (TOC), prevodnost, vrednost pH in koncentracije plinov CH4, O2, CO2 ter H2S. Testirali smo vzorce blata iz čistilnih naprav, obrečne trave (vrste širokolistni rogoz) in njune kombinacije. Analize smo opravili z dvema tehnikama predobdelave, s predobdelavo pri povišani temperaturi in s fermentacijo z dodatkom vsebine vampa. Prisotnost večine parametrov (KPK, NPK, NH3, celotni organski C) pred in po predobdelavi smo merili s kivetnimi testi, s senzorji smo izmerili pH in prevodnost ter zgolj po predobdelavi smo z analizatorjem plinov merili sestavo plinov. Ugotovili smo, da izbrane tehnike predobdelave vplivajo na vsebnost parametrov v biomasi, ki smo jih analizirali. Večina parametrov se je s predobdelavo spremenila. Vrednosti KPK so se večinoma povečale, predvsem v primeru trave. S predobdelavo je vrednost pH v vzorcih padla. Prevodnost je narastla po predobdelavi in se zmanjšala ob dodatku vsebine iz vampa. Koncentracija CH4 je prav tako narastla po predobdelavi, zlasti pri dodatku vsebine vampa. Analiza NPK je pokazala, da ima najvišjo vrednost makrohranil kombinacija blata in trave. Ko smo vzorcem dodali vsebino vampa ali travo, smo opazili manjši dvig razmerja C/N.
Ključne besede: lignocelulozna biomasa, predobdelava biomase, predobdelava pri povišani temperaturi, fermentacija s vsebino vampa, določanje nekaterih parametrov
Objavljeno v DKUM: 10.10.2019; Ogledov: 1893; Prenosov: 162
Celotno besedilo (3,22 MB)